ELONGATED MANIPULTOR.

TECHNICAL FIELD

The present invention relates to a method of moving a first rod and a second rod of a first actuating unit of a fluid actuator arrangement. The present invention also relates to an interlinked elongated manipulator and to a fluid actuator arrangement comprising a first actuating unit which comprises a first piston of a first cylinder, a second piston of a second cylinder, a first rod engagable to the first piston by a first clamping body of the first piston and to the second piston by a second clamping body of the second piston, a second rod engagable to the first piston by a third clamping body of the first piston and to the second piston by a fourth clamping body of the second piston, a fluid supply is coupled to the first and second cylinder and to the first, second, third, fourth clamping body, and is configured to pressurize the first cylinder for moving the first piston and to pressurize the first clamping body for engaging the first piston to the first rod and to pressurize the second cylinder for holding the second piston and to pressurize the fourth clamping body for engaging the second piston to the second rod.

The invention concerns the industry using hydraulic actuators in compact systems having a fluid actuator that can perform pitch/yaw action. It also concerns the robot industry manufacturing interlinked elongated manipulators comprising using fluid actuators and components thereof.

Preferably, the invention concerns the industry producing and using snake arm robots configured for confined spaces, such as the interior of aircraft structures, drift mines and complex narrow tunnels.

BACKGROUND ART

Current fluid actuator arrangements applied to e.g. robot arms are not cost-effective to produce and operate. The current fluid actuator arrangements are also bulky and require additional actuators and additional valves for controlling the relative rotational motions, e.g. pitch or yaw motion of the actu- ating units of fluid actuator arrangement.

There is a need for snake-arm robots (interlinked elongated manipulators) that are capable of sealing, drilling, inspecting the inside of confined spaces of aircraft structures.

There is a need for an interlinked elongated manipulator that can be used for drifting in mining where access only is possible through confined spaces or drifts following a vein. US 4 107 948 discloses a flexible robot arm comprising a number of mutually connected rigid links and operatively adapted to perform controlled bending movements driven by robot drive means.

SUM MARY OF THE INVENTION

There is an object to provide a compact fluid actuator arrangement of the type defined in the introduction.

There is an object to provide a compact fluid actuator arrangement of the type defined in the intro- duction that is cost-effective to produce and operate.

A yet further object is to provide a fluid actuator arrangement that can be used for operating e.g. robot snake arm or other type of interlinked elongated manipulator or other manipulator. A yet further object is to provide a lightweight fluid actuator arrangement.

One object is to provide a multi-piston rod fluid actuator arrangement designed as single unit.

Fluid actuator arrangements of today use several components, such as a plurality of pistons and cylinders, several valves, which make them costly to produce and maintain.

This or at least one of said objects has been achieved by a method of moving a first rod and a second rod of a first actuating unit of a fluid actuator arrangement, the first actuating unit comprises, a first piston of a first cylinder housing, a second piston of a second cylinder housing, the first rod is engagable to the first piston by a first clamping body of the first piston and is engagable to the second pis- ton by a second clamping bod of the second piston, the second rod is engagable to the first piston by a third clamping body of the first piston and is engagable to the second piston by a fourth clamping body of the second piston, a fluid supply is coupled to the first and second cylinder housing and to the first, second, third, fourth clamping body, the method comprises the steps of pressurizing the first cylinder housing for moving the first piston, pressurizing the first clamping body for engaging the first piston to the first rod, pressurizing the second cylinder housing for holding the second piston; pressurizing the fourth clamping body for engaging the second piston to the second rod.

Suitably, the first rod is adapted to translate its longitudinal motion in a first longitudinal direction into a yaw motion of the first holding member relatively the first actuating unit and the second rod is adapted to translate its longitudinal motion in the first longitudinal direction into a pitch motion of the first holding member relatively the first actuating unit.

In such way is achieved a compact, lightweight, cost-effective fluid actuator arrangement adapted for an interlinked elongated manipulator.

In such way there is achieved a compact fluid actuator arrangement (an interlinked elongated manipulator) that is less bulky than any common electrical interlinked elongated manipulator. Current electrical interlinked elongated manipulators require bulky disc-shaped electrical motors in each pivotal joint.

Preferably, the first cylinder housing is rigidly coupled to the second cylinder housing. Preferably, the first actuating unit comprises a first end and a second end.

Preferably, a first holding member is coupled to the first rod via a first pivot joint and to the second rod via a second pivot joint.

Preferably, the first end of the first actuating unit is coupled to the first holding member via a first pivot joint arrangement.

Preferably, the first rod is adapted to translate its longitudinal motion in the first longitudinal direction into a yaw motion of the first holding member relatively the first actuating unit.

Preferably, the second rod is adapted to translate its longitudinal motion in the first longitudinal direction into a pitch motion of the first holding member relatively the first actuating unit.

Suitably, the fluid actuator arrangement comprises a second actuating unit pivotally coupled to the first actuating unit and configured to move a third rod and a fourth rod, the second actuating unit comprises a third piston of a third cylinder housing, a fourth piston of a fourth cylinder housing, the third rod is engagable to the third piston by a fifth clamping body of the third piston and is engagable to the fourth piston P4 by a sixth clamping body of the fourth piston, the fourth rod is engagable to the third piston by a seventh clamping body of the third piston and is engagable to the fourth piston by a eight clamping body of the fourth piston, the fluid supply is coupled to the third and fourth cylinder housing and to the fifth, sixth, seventh and eight clamping body, the method further comprises the steps of pressurizing the third cylinder housing for moving the third piston; pressurizing the fifth clamping body for engaging the third piston to the third rod; pressurizing the fourth cylinder housing for holding the fourth piston; pressurizing the eight clamping body for engaging the fourth piston to the fourth rod. Suitably, the third rod is adapted to translate its longitudinal motion in a second longitudinal direction into a yaw motion of the second holding member relatively a second actuating unit and the fourth rod is adapted to translate its longitudinal motion in the second longitudinal direction into a pitch motion of the second holding member relatively the second actuating unit. Preferably, the third cylinder housing is rigidly coupled to the fourth cylinder housing.

Preferably, the second actuating unit comprises a first end and a second end.

Preferably, a second holding member is coupled to the third rod via a third pivot joint and to the fourth rod via a fourth pivot joint.

Preferably, the first end of the second actuating unit is coupled to the second holding member via a second pivot joint arrangement.

In such way is achieved an interlinked elongated manipulator comprising actuating units mounted in series, whereby the actuating units are operated by the control unit to perform pivotal motion (pitch and yaw) relative each other.

Preferably, the third rod is adapted to translate its longitudinal motion in the second longitudinal di- rection into a yaw motion of the second holding member relatively the second actuating unit.

Preferably, the fourth rod is adapted to translate its longitudinal motion in the second longitudinal direction into a pitch motion of the second holding member relatively the second actuating unit.

Suitably, the fluid actuator arrangement comprises a fifth and a sixth rod each extending through the respective first and second piston, the fifth rod is engagable to the first piston by a ninth clamping body of the first piston and is engagable to the second piston by a tenth clamping body of the second piston; the sixth rod is engagable to the first piston by a eleventh clamping body of the first piston and is engagable to the second piston by a twelfth clamping body of the second piston; the fluid supply is coupled to the ninth, tenth, eleventh, twelfth clamping body, the method further comprises the steps of pressurizing the first cylinder housing for moving the first piston; pressurizing the ninth clamping body for engaging the first piston to the fifth rod; pressurizing the second cylinder housing for holding the second piston; pressurizing the twelfth clamping body for engaging the second piston to the sixth rod.

In such way is achieved clean outer environment by the use of one common cylinder housing for several rods. Preferably, the second holding member is coupled to the fifth rod via a fifth pivot joint and to the sixth rod via a sixth pivot joint.

Preferably, the second end of the first actuating unit is coupled to the second holding member via a third pivot joint arrangement. Preferably, the fifth rod is adapted to translate its longitudinal motion in the first longitudinal direction into a yaw motion of the second holding member relatively the first actuating unit.

Preferably, the sixth rod is adapted to translate its longitudinal motion in the first longitudinal direction into a pitch motion of the second holding member relatively the first actuating unit.

Suitably, the fluid actuator arrangement comprises a seventh and an eighth rod each extending through the respective third and fourth piston, the seventh rod is engagable to the third piston by a thirteenth clamping body of the third piston and is engagable to the fourth piston by a fourteenth clamping body of the fourth piston, the eighth rod R8 is engagable to the third piston by a fifthteenth clamping body of the third piston and is engagable to the fourth piston by a sixteenth clamping body of the fourth piston, the fluid supply is coupled to the thirteenth, fourteenth, fifthteenth, sixteenth clamping body, the method further comprises the steps of pressurizing the third cylinder housing for moving the third piston, pressurizing the thirteenth clamping body for engaging the third piston to the seventh rod, pressurizing the fourth cylinder housing for holding the fourth piston, pressurizing the sixteenth clamping body for engaging the fourth piston to the eight rod.

Preferably, a third holding member is coupled to the seventh rod via a seventh pivot joint and to the eighth rod via an eighth pivot joint.

Preferably, the second end of the second actuating unit is coupled to the third holding member via a fourth pivot joint arrangement.

Preferably, the seventh rod is adapted to translate its longitudinal motion in the second longitudinal direction into a yaw motion of the third holding member relatively the second actuating unit. Preferably, the eighth rod is adapted to translate its longitudinal motion in the second longitudinal direction into a pitch motion of the third holding member relatively the second actuating unit.

In such way is achieved an interlinked elongated manipulator comprising actuating units mounted in series, whereby the actuating units are operated by the control unit to perform pivotal motion (pitch and yaw) relative each other and which interlinked elongated manipulator is suitable for confined spaces (aircraft structure interiors, narrow drift mines etc.). Preferably, the first piston is slidable arranged in the first cylinder housing along a first longitudinal axis.

Preferably, the second piston is slidable arranged in the second cylinder housing along the first longitudinal axis. Preferably, the third piston is slidable arranged in the third cylinder housing along a second longitudinal axis.

Preferably, the fourth piston is slidable arranged in the fourth cylinder housing along the second longitudinal axis.

Preferably, the first and second rods extend along the first longitudinal axis. Preferably, the fifth and sixth rods extend along the first longitudinal axis.

Preferably, the third and fourth rods extend along the second longitudinal axis.

Preferably, the seventh and eight rods extend along the second longitudinal axis.

Preferably, a first end of the first rod is coupled to a first holding member (holding member may also be called intermediate linkage member). Preferably, the first end of the first rod and the first end of the second rod may be coupled to a first holding member, which may comprise an end effector or tool carrying member.

Preferably, a first end of the second rod is coupled to the first holding member.

Preferably, a first end of the fifth rod is coupled to a second holding member.

Preferably, a first end of the sixth rod is coupled to the second holding member. Preferably, the first cylinder housing is rigidly coupled to the second cylinder housing.

Preferably, the first cylinder housing comprises a first outer cap end.

Preferably, the second cylinder housing comprises a second outer cap end.

Preferably, the third cylinder housing is rigidly coupled to the fourth cylinder housing.

Preferably, the third cylinder housing comprises a third outer cap end. Preferably, the fourth cylinder housing comprises a fourth outer cap end. Preferably, the first and second outer cap ends face away from each other along the first longitudinal axis.

Preferably, the third and fourth outer cap ends face away from each other along the second longitudinal axis. Preferably, a first end of the third rod is coupled to the second holding member.

Preferably, a first end of the fourth rod is coupled to the second holding member.

Preferably, a first end of the seventh rod is coupled to a third holding member.

Preferably, a first end of the eighth rod is coupled to the third holding member.

Preferably, the first end of the first rod faces away in an opposite direction relative the direction of that the first end of the fifth rod faces way along the first longitudinal axis.

Preferably, the first end of the second rod faces away in an opposite direction relative the direction of that the first end of the sixth rod faces way along the first longitudinal axis.

Preferably, the first end of the third rod faces away in an opposite direction relative the direction of that the first end of the seventh rod faces way along the second longitudinal axis. Preferably, the first end of the fourth rod faces away in an opposite direction relative the direction of that the first end of the eighth rod faces way along the second longitudinal axis.

Preferably, the fluid actuator arrangement comprises a third actuating unit configured to move a ninth, tenth, eleventh, twelfth rod, the third actuating unit comprises a fifth piston of a fifth cylinder housing, a sixth piston of a sixth cylinder housing, the ninth rod is engagable to the fifth piston by a seventeenth clamping body of the fifth piston and is engagable to the sixth piston by an eighteenth clamping body of the sixth piston, the tenth rod is engagable to the fifth piston by a nineteenth clamping body of the fifth piston and is engagable to the sixth piston by a twentieth clamping body of the sixth piston, the fluid supply is coupled to the fifth and sixth cylinder housing and to

the seventeenth, eighteenth, nineteenth and twentieth clamping body, the method further com- prises the steps of pressurizing the fifth cylinder housing for moving the fifth piston, pressurizing the seventeenth clamping body for engaging the fifth piston to the ninth rod, pressurizing the sixth cylinder housing for holding the sixth piston, pressurizing the twentieth clamping body for engaging the sixth piston to the tenth rod. Preferably, the eleventh rod is engagable to the fifth piston by a twenty-first clamping body of the fifth piston and is engagable to the sixth piston by a twenty-second clamping body of the sixth piston.

Preferably, the twelfth rod is engagable to the fifth piston by a twenty-third clamping body of the fifth piston and is engagable to the sixth piston by a twenty-fourth clamping body of the sixth piston. Preferably, the fluid supply is coupled to the fifth and sixth cylinder housing and to the twenty-first, the twenty-second, the twenty-third and the twenty-fourth clamping body.

Preferably, the fifth piston is slidable arranged in the fifth cylinder housing along a third longitudinal axis.

Preferably, the sixth piston is slidable arranged in the sixth cylinder housing along the third longitudi- nal axis.

Preferably, the respective ninth and a tenth rod extends along the third longitudinal axis.

Preferably, the respective eleventh and twelfth rod extends along the third longitudinal axis.

Preferably, a first end of the ninth rod is coupled to the third holding member.

Preferably, a first end of the tenth rod is coupled to the third holding member. Preferably, a first end of the eleventh rod is coupled to a fourth holding member.

Preferably, a first end of the twelfth rod is coupled to the fourth holding member.

Preferably, the fifth cylinder housing is rigidly coupled to the sixth cylinder housing.

Preferably, the fifth cylinder housing comprises a fifth outer cap end.

Preferably, the sixth cylinder housing comprises a sixth outer cap end. Preferably, the fifth and sixth outer cap ends face away from each other along the third longitudinal axis.

Preferably, the first end of the ninth rod faces away in an opposite direction relative the direction of that the first end of the eleventh rod faces way along the third longitudinal axis.

Preferably, the first end of the tenth rod faces away in an opposite direction relative the direction of that the first end of the twelfth rod faces way along the third longitudinal axis. Preferably, the fluid supply is coupled to the first and second cylinder housing and to the first, second, third and fourth clamping body via valve arrangement.

Preferably, the fluid supply is coupled to the third and fourth cylinder housing and to the fifth, sixth, seventh, eighth clamping body via the valve arrangement. Preferably, the fluid supply is coupled to the fifth and sixth cylinder housing and to the seventeenth, eighteenth, nineteenth, twentieth clamping body via the valve arrangement.

Preferably, the fluid supply is coupled to the ninth, tenth, eleventh, twelfth, thirteenth, fourteenth, fifthteenth, sixteenth clamping body via the valve arrangement.

Preferably, the respective valve arrangement coupled to the respective clamping body comprises an on/off valve and/or 3/2-valve or other suitable valve.

Preferably, the respective on/off valve and/or 3/2-valve is arranged within the respective piston.

In such way is achieved a minimum number of hydraulic cables exterior fluid actuator arrangement.

In such way is achieved a reliability in operation of the fluid actuator arrangement as the risk of breaking hydraulic fluid hoses exterior the fluid actuator arrangement being minimized. Preferably, the respective on/off valve and/or 3/2-valve arranged within the respective piston is coupled for fluid communication with the respective clamping body via a channel system provided in the respective piston.

Suitably, the first actuating unit is coupled to the second actuating unit via a pivot joint arrangement and/or a double pivot joint arrangement and/or a linkage pivot joint arrangement assembly. Preferably, the second actuating unit is coupled to the third actuating unit via a pivot joint arrangement and/or a double pivot joint arrangement and/or a linkage pivot joint arrangement assembly.

Preferably, the first piston divides the first cylinder housing in a first and second cylinder chamber, each first and second cylinder chamber is coupled to the fluid supply via the valve arrangement for controlling the pressurization of the respective first and second cylinder chamber.

Preferably, the second piston divides the second cylinder housing in a first and second cylinder chamber, each first and second cylinder chamber is coupled to the fluid supply via the valve arrangement for controlling the pressurization of the respective first and second cylinder chamber. Such dividing of the cylinder house may be a configuration of the other actuating units as well (third cylinder housing, fourth cylinder housing, fifth cylinder housing, sixth cylinder housing etc.).

In such way is achieved high rigidity and precision of the interlinked elongated manipulator.

Preferably, the fluid actuator arrangement comprises a control unit coupled to the valve arrangement for controlling the motion of the first piston and of the second piston by pressurization of the respective first and second cylinder chamber of the first actuating unit. Preferably, the valve arrangement for controlling the motion of the first piston and of the second piston by pressurization of the respective first and second cylinder chamber of the first actuating unit comprises a servo valve and/or a logic valve or other suitable valve.

Preferably, the control unit is coupled to the valve arrangement for controlling the motion of the third piston and of the fourth piston by pressurization of the respective first and second cylinder chamber of the second actuating unit.

Preferably, the valve arrangement comprises a logic valve member, spool type logic valves, directional control valves, a spring biased logic valve, etc.

Preferably, the valve arrangement controls the pressurization of the respective clamping body.

In such way is achieved a switching time of milliseconds. The use of logic valve members (on /off valves such as 3/2 valves) implies that small valves can be used having low power consumption be- cause of the low flow operation and small volume changes in the respective space of each clamping element and/or clamping member during pressurization.

Preferably, the logic valve members are arranged within the respective piston and may be designed as logic valve cartridges. Preferably, the respective clamping body comprises a flexible membrane formed by an inner wall of the respective piston body for forming a space of the piston body, which respective space is expandable and is coupled for fluid communication with the fluid supply. Preferably, the engaging and/or disengaging of the respective clamping body to and/or from the respective rod being achieved by pressurizing the respective flexible membrane with a first and/or second fluid pressure.

Preferably, the first fluid pressure being higher than the second fluid pressure, wherein the first fluid pressure expands the respective space for pressing the flexible membrane toward the rod providing a clamping of the piston to the rod.

Preferably, the fluid actuator arrangement comprises a cushioning valve arrangement for providing a dampening feature of the piston.

This or at least one of said objects has been achieved by a fluid actuator arrangement comprising a first actuating unit which comprises a first piston of a first cylinder; a second piston of a second cylinder; a first rod engagable to the first piston by a first clamping body of the first piston and to the second piston by a second clamping body of the second piston; a second rod engagable to the first pis- ton by a third clamping body of the first piston and to the second piston by a fourth clamping body of the second piston; a fluid supply is coupled to the first and second cylinder and to the first, second, third, fourth clamping body, and is configured to pressurize the first cylinder for moving the first piston and to pressurize the first clamping body for engaging the first piston to the first rod and to pressurize the second cylinder for holding the second piston and to pressurize the fourth clamping body for engaging the second piston to the second rod.

In such way is achieved an energy-efficient fluid actuator arrangement adaptable to perform pitch/yaw movements.

Suitably, the first actuating unit is pivotally coupled to a second actuating unit which comprises a third piston of a third cylinder; a fourth piston of a fourth cylinder; a third rod engagable to the third piston by a fifth clamping body of the third piston and engagable to the fourth piston by a sixth clamping body of the fourth piston; a fourth rod engagable to the third piston by a seventh clamping body of the third piston and engagable to the fourth piston by an eighth clamping body of the fourth piston; the fluid supply is coupled to the third and fourth cylinder and to the fifth, sixth, seventh, eighth clamping body, and is configured to pressurize the third cylinder for moving the third piston and to pressurize the fifth clamping body for engaging the third piston to the third rod and to pressurize the fourth cylinder for holding the fourth piston and to pressurize the eighth clamping body for engaging the fourth piston to the fourth rod. Preferably, the first actuating unit is coupled to the second actuating unit via a pivot joint arrangement and/or a double pivot joint arrangement and or a linkage pivot joint arrangement assembly.

Suitably, the fluid actuator arrangement comprises a fifth and a sixth rod each extending through the respective first and second piston; the fifth rod is engagable to the first piston by a ninth clamp- ing body of the first piston and is engagable to the second piston by a tenth clamping body of the second piston; the sixth rod is engagable to the first piston by a eleventh clamping body of the first piston and is engagable to the second piston by a twelfth clamping body of the second piston; the fluid supply is coupled to the ninth, tenth, eleventh, twelfth clamping body.

Suitably, the fluid actuator arrangement comprises a seventh and an eighth rod each extending through the respective third and fourth piston; the seventh rod is engagable to the third piston by a thirteenth clamping body of the third piston and is engagable to the fourth piston by a fourteenth clamping body of the fourth piston; the eighth rod is engagable to the third piston by a fifthteenth clamping body of the third piston and is engagable to the fourth piston by a sixteenth clamping body of the fourth piston; the fluid supply is coupled to the thirteenth, fourteenth, fifthteenth and six- teenth clamping body.

Suitably, a second holding member is coupled between the first and second actuating unit, and is coupled to the respective third, fourth, fifth, sixth rod.

Preferably, there is provided a fluid actuator arrangement comprising actuating units (Al, A2, A3...A _n ) of nth numbers, wherein each actuating unit comprises a first piston of a first cylinder housing; a second piston of a second cylinder housing; a first rod engagable to the first piston by a first clamping body of the first piston and to the second piston by a second clamping body of the second piston; a second rod engagable to the first piston by a third clamping body of the first piston and to the second piston by a fourth clamping body of the second piston; a fluid supply is coupled to the first and second cylinder housing and to the first, second, third and fourth clamping body and is configured to pressurize the first cylinder housing for moving the first piston and to pressurize the first clamping body for engaging the first piston to the first rod and to pressurize the second cylinder housing for holding the second piston and to pressurize the fourth clamping body for engaging the second piston to the second rod.

Suitably, the second holding member serves as an elongated passive (slave) member. Suitably, the second holding member serves as a hollow elongated passive (slave) member configured to encompass functional components for operating the fluid actuator arrangement or parts thereof. Suitably, a first holding member comprises an end effector and is coupled to the first actuating unit via a pivot joint arrangement.

Preferably, a third holding member is coupled between the second and third actuating unit, and is coupled to the respective seventh, eighth, ninth and tenth rod.

Preferably, a fourth holding member is coupled to the eleventh and twelfth rod.

Suitably, the first holding member is coupled to the first and/or second and/or third and/or fourth rod via a wire arrangement.

Preferably, the wire is a cable or a piano wire and may be guided through the respective first and second piston. The wire may be metal wire or may be made of any non-metallic material.

Suitably, the cable or a piano wire is guided through a bronze sleeve configured to guide the cable or a piano wire with low friction.

Suitably, the first holding member is coupled to the first and/or second and/or third and/or fourth rod via a band and/or strip arrangement.

Suitably, the band and/or strip arrangement comprises steel or other metallic material or may be made of any non-metallic material.

Suitably, the first rod comprises a holding member joining end that is flexible.

Suitably, the first rod tapers toward a holding member joining end providing flexibility.

Preferably, the first rod is coupled to the first holding member via a pivot joint arrangement.

Preferably, the second holding member is configured as a first intermediate linkage member comprising an electronic device and/or a valve member and/or fluid supply means.

Preferably, the first piston body comprises at least three rods.

Preferably, the fluid actuator arrangement comprises a third actuating unit and/or a series of actuating units pivotally coupled to the second actuating unit

Preferably, the fluid actuator arrangement comprises an assembly of corresponding components similar to that of the first and second actuating unit; the fluid supply is coupled to the third actuating unit. Preferably, the actuating units are pivotally coupled to each other via a pivot joint for permitting yaw and pitch rotational motion.

Preferably, the actuating units is pivotally coupled to each other in a repetitive manner, wherein the principle of each actuating unit and each rod is the same or at least similar. Preferably, the first actuating unit is pivotally coupled (for performing pitch and yaw motion relative the second actuating unit) to the second actuating unit.

Preferably, the second actuating unit is pivotally coupled (for performing pitch and yaw motion relative the third actuating unit) to the third actuating unit.

Preferably, the third actuating unit is pivotally coupled (for performing pitch and yaw motion relative the fourth actuating unit) to the fourth actuating unit.

Preferably, the fourth actuating unit is pivotally coupled (for performing pitch and yaw motion relative the fifth actuating unit) to the fifth actuating unit.

Preferably, the first actuating unit is pivotally coupled (for performing pitch and yaw motion relative the second actuating unit) to the second actuating unit via a passive member. Preferably, the fluid actuator arrangement comprises a series of actuating units each pivotally coupled to the other via a respective holding member and/or passive member.

Preferably, the passive member encompasses operational equipment, such as fluid supply and/or electrical fluid pump device and/or valve arrangement and/or control unit etc.

In such way is achieved a cost-effective robot operation for performing yaw and pitch motion. Preferably, the respective rod coupled to the holding member is coupled to the holding member via a universal joint.

Preferably, the respective rod coupled to the holding member is coupled to a first side of the holding member via a first wire and/or strip arrangement, wherein the other end of the rod is coupled to a second wire and/or strip arrangement in turn coupled to a second side of the holding member, thus providing a rigid closed loop.

Preferably, the (first, second, third, etc.) clamping body comprises an expandable space (first, second, third, etc.) configured to provide a clamping action of the piston (first, second, third, etc.) to the rod when the expandable space is pressurized by the fluid supply. Preferably, a flexible rod engagement wall of the piston is configured to move in radial direction inward toward the outer envelope surface of the rod for providing a clamping action.

Preferably, the (first, second, third, etc.) clamping body may be configured as any suitable configuration for providing a clamping action between the piston and the respective rod. This or at least one of said objects has been achieved by an interlinked elongated manipulator comprising fluid actuator arrangement according to any of claims 5 to 14, the fluid actuator arrangement comprises a control unit coupled to a valve arrangement and configured to control the moving of a first rod and a second rod of a first actuating unit of a fluid actuator arrangement according to any of the method claims 1 to 4. Preferably, the control unit is coupled to a valve arrangement and is configured to control the moving of the third rod and/or the fourth rod and/or the third rod and/or the fourth rod and/or fifth rod and/or sixth rod.

In such way is achieved that cost-effective use of directional valves and PLC (Programmable logic controller) can be used for the fluid actuator arrangement. This or at least one of said objects has been achieved by a data medium storing program adapted for controlling the moving of a first rod and a second rod of a first actuating unit of a fluid actuator arrangement of the interlinked elongated manipulator according to claim 15, wherein said data medium storing program comprises a program code stored on a medium, which is readable on a computer, for causing the control unit to perform the method steps of pressurizing the first cylinder housing for moving the first piston; pressurizing the first clamping body for engaging the first piston to the first rod; pressurizing the second cylinder housing for holding the second piston; pressurizing the fourth clamping body for engaging the second piston to the second rod.

This or at least one of said objects has been achieved by a data medium storing program product comprising a program code stored on a medium, which is readable on a computer, for performing the method steps according to the method claims 1 to 4, when a data medium storing program according to claim 18 is run on the control unit.

The definition of pivot joint arrangement may comprise universal joint, double universal joint, pivot joint linkage etc. BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will now be described by way of examples with references to the accompanying schematic drawings, of which:

Fig. 1 illustrates a fluid actuator arrangement according to a first example of the invention and/or a portion of the first example;

Fig. 2 illustrates a fluid actuator arrangement according to a second example of the invention;

Fig. 3 illustrates a fluid actuator arrangement according to a third example of the invention;

Fig. 4 illustrates a feedback loop diagram according to a fourth example of the invention;

Fig. 5 illustrates a fluid actuator arrangement according to a fifth example of the invention;

Fig. 6 illustrates a fluid actuator arrangement according to a sixth example of the invention;

Fig. 7 illustrates a fluid actuator arrangement according to a seventh example of the invention;

Fig. 8a illustrates a fluid actuator arrangement according to an eighth example of the invention;

Fig. 8b illustrates a fluid actuator arrangement according to a further example of the invention;

Fig. 9 illustrates a fluid actuator arrangement according to a ninth example of the invention;

Fig. 10 illustrates a fluid actuator arrangement according to a tenth example of the invention;

Fig. 11 illustrates a fluid actuator arrangement according to an eleventh example of the invention;

Fig. 12 illustrates a fluid actuator arrangement according to a twelfth example of the invention;

Fig. 13 illustrates a fluid actuator arrangement according to a thirteenth example of the invention;

Fig. 14 illustrates a fluid actuator arrangement according to a fourteenth example of the invention;

Fig. 15 illustrates a flow chart of a method according to a fifthteenth example of the invention;

Fig. 16 illustrates a flow chart of a method according to a sixteenth example of the invention; and

Fig. 17 illustrates a CPU device of a fluid actuator arrangement according to a seventeenth example of the invention. DETAILED DESCRIPTION

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings, wherein for the sake of clarity and understanding of the invention some details of no importance may be deleted from the drawings. Same reference may indicate similar detail, even though it refers to another embodiment.

Fig. 1 schematically illustrates components of a fluid actuator arrangement 1 comprising a first actuating unit Al. The first actuating unit Al comprises a first piston PI of a first cylinder CI and a second piston P2 of a second cylinder C2. The first actuating unit 1 further comprises a first rod Rl which is engagable to the first piston PI by means of a first clamping body Bl of the first piston PI. The first rod Rl is engagable to the second piston P2 by means of a second clamping body B2 of the second piston P2. The first actuating unit Al further comprises a second rod R2 that is engagable to the first piston PI by means of a third clamping body B3 of the first piston PI and that is engagable to the second piston P2 by a fourth clamping body B4 of the second piston P2.

The fluid actuator arrangement 1 further comprises a fluid supply 3 that is coupled to the first CI and second C2 cylinder. The fluid supply 3 is also coupled to the first, second, third and fourth clamping body. The fluid supply comprises a valve arrangement (not shown) and is configured to pressurize the first cylinder CI for moving the first piston PI forward or backward along the longitudinal direction X. The fluid supply 3 is also configured to pressurize the first clamping body Bl for engaging the first piston PI to the first rod Rl, wherein a first flexible membrane (not shown) is pressed toward the first rod Rl. The first rod Rl will thus be moved. The fluid supply 3 is furthermore configured to pressurize the second cylinder C2 for holding the second piston P2 in a locked position relative the second cylinder C2. The fluid supply 3 is configured to pressurize the fourth clamping body B4 for engaging the second piston P2 to the second rod R2 for locking the second rod R2.

Preferably, the respective clamping body comprises a flexible membrane formed by an inner wall of the respective piston body for forming a space of the piston body, which respective space is expandable and is coupled for fluid communication with the fluid supply.

Preferably, the engaging and/or disengaging of the respective clamping body to and/or from the respective rod being achieved by pressurizing the respective flexible membrane with a first and/or second fluid pressure. Preferably, the first fluid pressure being higher than the second fluid pressure for providing that the first fluid pressure expands the respective space and press the respective flexible membrane toward the rod providing a clamping of the piston to the respective rod that is required to be engaged. Preferably, the piston divides the respective cylinder in a first and second cylinder chamber, each first and second cylinder chamber is coupled to the fluid supply 3 via the valve arrangement for controlling the pressurization of the respective first and second cylinder chamber.

The fluid supply 3 is furthermore configured to pressurize the second cylinder C2 for moving the sec- ond piston P2 forward or backward along the longitudinal direction X. The fluid supply 3 is also configured to pressurize the fourth clamping body B4 for engaging the second piston P2 to the second rod R2, wherein a fourth flexible membrane is pressed toward the second rod R2. The second rod R2 will thus be engaged. The fluid supply is furthermore configured to pressurize the second cylinder C2 for holding the second piston P2. The second rod is thereby locked.

A first end of the first rod Rl and a first end of the second rod R2 being coupled to a first holding member H I. The first holding member H I is coupled to the first actuating unit 1 via a first pivot joint arrangement J l. The first holding member H I may comprise an end effector or tool carrying member. The first holding member H I is coupled to the first and/or second and/or third and/or fourth rod via a wire arrangement 5. Accordingly, by means of said pressurization, the first holding member H I will perform a pitch and/or yaw rotational motion.

Fig. 2 schematically illustrates components of a fluid actuator arrangement 1 according to a second example of the invention. The fluid actuator arrangement 1 comprises a first actuating unit Al comprising a first piston PI of a first cylinder CI, a second piston P2 of a second cylinder C2, a first rod Rl is engagable to the first piston PI by a first clamping body Bl of the first piston PI and to the second piston P2 by a second clamping body B2 of the second piston P2, a second rod R2 engagable to the first piston PI by a third clamping body B3 of the first piston PI and to the second piston P2 by a fourth clamping body B4 of the second piston P2, a fluid supply 3 is coupled to the first CI and second cylinder C2 and to the first Bl, second B2, third B3, fourth B4 clamping body, and is configured to pressurize the first cylinder CI for moving the first piston PI and to pressurize the first clamping body Bl for engaging the first piston PI to the first rod Rl and to pressurize the second cylinder C2 for holding the second piston P2 and to pressurize the fourth clamping body B4 for engaging the second piston P2 to the second rod R2. The first piston PI extends with a cylinder shaped body out from the first cylinder CI first end cap in one direction and from the first cylinder second end cap in another direction in the longitudinal direction X. The first piston PI further comprises a sleeve shaped protrusion that extends in radial direction from the cylinder shaped body envelope surface mid-section. The protrusion extends toward an inner cylinder wall of the first cylinder CI.

The second piston P2 extends with a cylinder shaped body out from the second cylinder C2 first end cap in one direction and from the second cylinder second end cap in another direction in the longitudinal direction. The second piston P2 further comprises a sleeve shaped protrusion that extends in radial direction from the cylinder shaped body envelope surface mid-section. The protrusion extends toward an inner cylinder wall of the second cylinder C2.

The first actuating unit is coupled to a second actuating unit (not shown in Fig. 2, an example is shown in Fig. 3) which comprises a third piston of a third cylinder and a fourth piston of a fourth cylinder.

The direction of travel of the respective piston is preferably controlled by means of a directional servo control valve or a proportional servo valve.

The fluid actuator arrangement 1 comprises a fifth R5 and a sixth rod R6 each extending through the respective first PI and second piston P2, the fifth rod R5 is engagable to the first piston PI by a ninth clamping body B9 of the first piston PI and is engagable to the second piston P2 by a tenth clamping bod BIO of the second piston P2, the sixth rod R6 is engagable to the first piston PI by a eleventh clamping body Bll of the first piston PI and is engagable to the second piston P2 by a twelfth clamping body B12 of the second piston P2, the fluid supply 3 is coupled to the ninth B9, tenth BIO, eleventh Bll and twelfth B12 clamping body via a valve arrangement 5. A control unit CU is arranged and configured to control the motions of the piston rods. The control unit CU is coupled to the valve arrangement 5 and is coupled to a sensor arrangement (not shown) for detecting of actual piston rod motion values and/or holding member angular values.

Fig. 3 illustrates a fluid actuator arrangement 1 of an interlinked elongated manipulator according to a third example of the invention. The fluid actuator arrangement 1 comprises a first actuating unit Al including a first piston PI of a first cylinder CI, a second piston P2 of a second cylinder C2 and including a first rod Rl and a second rod R2. The first actuating unit Al is coupled to a second actuating unit A2 via a second holding member H2 (it may also be called a first intermediate member). The second actuating unit A2 comprises a third piston P3 of a third cylinder C3, a fourth piston P4 of a fourth cylinder C4, a third rod R3 engagable to the third piston P3 by a fifth clamping body B5 of the third piston P3 and engagable to the fourth piston P4 by a sixth clamping body B6 of the fourth piston P4, a fourth rod R4 engagable to the third piston P3 by a seventh clamping body B7 of the third piston P3 and engagable to the fourth piston P4 by an eighth clamping body B8 of the fourth piston P4. A fluid supply (not shown) is coupled to the cylinders and clamping bodies via a valve arrangement (not shown) for providing individual movement of the respective rod, whereas they utilize common pistons. A control unit CU is provided to the interlinked elongated manipulator for control- ling the operation of a valve arrangement (not shown) coupled to a fluid supply (not shown) and to cylinder chambers of the cylinders and to the clamping bodies.

By means of moving the first Rl, second R2, third R3, fourth R4 rods and a fifth R5, sixth R6, seventh R7 and eighth rod R8 independently of each other by specific commands and sharing common pistons, there is achieved a pitch/yaw motion of a first HI, the second holding member H2 and a third holding member H3 coupled to an end effector. Accordingly, by means of said pressurization, an end effector of the third holding member H3 will perform a pitch and/or yaw rotational motion. Position sensors (not shown) and angular sensors (not shown) are arranged to the respective rod and to the respective holding member pivotal joint.

The fluid supply is thus also coupled to the third C3 and fourth cylinder C4 and to the fifth B5, sixth B6, seventh B7 and eighth clamping body B8, and is configured to pressurize the third cylinder C3 for moving the third piston P3 and to pressurize the fifth clamping body B5 for engaging the third piston P3 to the third rod R3 and to pressurize the fourth cylinder C4 for holding the fourth piston P4 and to pressurize the eighth clamping body B8 for engaging the fourth piston P4 to the fourth rod R4.

The fluid actuator arrangement 1 comprising the seventh R7 and the eighth rod R8 each extends through the respective third P3 and fourth piston P4. The seventh rod R7 is engagable to the third piston P3 by a thirteenth clamping body B13 of the third piston P3 and is engagable to the fourth piston P4 by a fourteenth clamping body B14 of the fourth piston P4. The eighth rod R8 is engagable to the third piston P3 by a fifthteenth clamping body B15 of the third piston P3 and is engagable to the fourth piston P4 by a sixteenth clamping body B16 of the fourth piston P4. The fluid supply (not shown) is coupled to the thirteenth B13, fourteenth B14, fifthteenth B15 and sixteenth B16 clamping body.

The first holding member HI is coupled to the first rod Rl via a first pivot joint Jl and to the second rod R2 via a second pivot joint J2. A first end of the first actuating unit Al is coupled to the first holding member HI via a first pivot joint arrangement Ul. The first rod Rl is adapted to translate its longitudinal motion in the first longitudinal direction XI into a yaw motion of the first holding member HI relatively the first actuating unit Al. The second rod R2 is adapted to translate its longitudinal motion in the first longitudinal direction into a pitch motion of the first holding member HI relatively the first actuating unit Al. The second holding member H2 is coupled to the third rod P3 via a third pivot joint J3 and to the fourth rod P4 via a fourth pivot joint J4. A first end of the second actuating unit A2 is coupled to the second holding member H2 via a second pivot joint arrangement U2. The third rod R3 is adapted to translate its longitudinal motion in the second longitudinal direction X2 into a yaw motion of the second holding member H2 relatively the second actuating unit A2. The fourth rod R4 is adapted to translate its longitudinal motion in the second longitudinal direction X2 into a pitch motion of the second holding member relatively the second actuating unit A2.

The fluid actuator arrangement 1 further comprises a fifth R5 and a sixth rod R6 each extending through the respective first PI and second piston P2. The fifth rod R5 is engagable to the first piston PI by a ninth clamping body B9 of the first piston PI and is engagable to the second piston P2 by a tenth clamping body BIO of the second piston P2, the sixth rod R6 is engagable to the first piston PI by a eleventh clamping body Bll of the first piston PI and is engagable to the second piston P2 by a twelfth clamping body B12 of the second piston P2. The fluid supply (not shown) is coupled to the ninth B9, tenth BIO, eleventh Bll and twelfth B12 clamping body: The fluid actuator arrangement 1 is configured for pressurizing the first cylinder housing CI for moving the first piston PI, pressurizing the ninth clamping body B9 for engaging the first piston PI to the fifth rod R5, pressurizing the second cylinder housing C2 for holding the second piston P2, pressurizing the twelfth clamping body B12 for engaging the second piston P2 to the sixth rod R6. The second holding member H2 is coupled to the fifth rod R5 via a fifth pivot joint J5 and to the sixth rod R6 via a sixth pivot joint J6. A second end of the first actuating unit Al is coupled to the second holding member H2 via a third pivot joint ar- rangement U3. The fifth rod R5 is adapted to translate its longitudinal motion in the first longitudinal direction XI into a yaw motion of the second holding member H2 relatively the first actuating unit Al. The sixth rod R6 is adapted to translate its longitudinal motion in the first longitudinal direction XI into a pitch motion of the second holding member H2 relatively the first actuating unit Al.

The fluid actuator arrangement comprises 1 a seventh R7 and an eighth rod R8 each extending through the respective third P3 and fourth piston P4. The seventh rod R7 is engagable to the third piston P3 by a thirteenth clamping body B13 of the third piston P3 and is engagable to the fourth piston P4 by a fourteenth clamping body B14 of the fourth piston P4. The eighth rod R8 is engagable to the third piston P3 by a fifthteenth clamping body B15 of the third piston P3 and is engagable to the fourth piston P4 by a sixteenth clamping body B16 of the fourth piston P4. The fluid supply (not shown) is coupled to the thirteenth B13, fourteenth B14, fifthteenth B15 and sixteenth B16 clamping body. The fluid actuator arrangement 1 is configured for pressurizing the third cylinder housing C3 for moving the third piston P3, pressurizing the thirteenth clamping body B13 for engaging the third piston P3 to the seventh rod R7, pressurizing the fourth cylinder housing C4 for holding the fourth piston P4, pressurizing the sixteenth clamping body B16 for engaging the fourth piston P4 to the eight rod R8. A third holding member H3 is coupled to the seventh rod R7 via a seventh pivot joint J7 and to the eighth rod R8 via an eighth pivot joint J8. A second end of the second actuating unit A2 is coupled to the third holding member H3 via a fourth pivot joint arrangement U4. The seventh rod R7 is adapted to translate its longitudinal motion in the second longitudinal direction X2 into a yaw mo- tion of the third holding member H3 relatively the second actuating unit A2. The eighth rod R8 is adapted to translate its longitudinal motion in the second longitudinal direction X2 into a pitch motion of the third holding member H3 relatively the second actuating unit A2.

Fig. 4 schematically illustrates a feedback loop diagram according to a fourth example of the invention. Preferably, the fluid actuator arrangement 1 is adapted for a feedback loop or closed loop using a sensor arrangement being coupled to a control unit CU controlling the valve arrangement (not shown) for regulating the fluid supply to the cylinder housings and individual clamping bodies. As being shown in Fig. 4, the control unit is fed with an input signal (command). The control unit CU commands the valve arrangement to pressurize a specific cylinder chamber for moving a specific piston. The piston P is engaged with the intended rod R and moves the rod R to a position defined by a desired position value and/or desired angular value. The actual sensor value AS of the rod and/or actual angular value of the holding member being measured by means of a position sensor and/or angular sensor. The actual sensor value is compared with the desired position value and/or desired angular value by means of the control unit. The output signal thus may comprise an adjustment command for correction of the fluid actuator arrangement position. Fig. 5 illustrates a fluid actuator arrangement 1 according to a fifth example of the invention. The fluid actuator arrangement 1 comprises a first actuating unit Al including a first piston PI of a first cylinder CI, a second piston P2 of a second cylinder C2 and including a first rod Rl and a second rod (not shown). The first actuating unit Al is coupled to a second actuating unit A2 via an intermediate member H2. The second actuating unit A2 comprises a third piston P3 of a third cylinder C3, a fourth piston P4 of a fourth cylinder C4 and comprises a third rod R3 and a fourth rod (not shown).

The first Al and second A2 actuating unit each comprises four rods. Only the rods Rl, R3 are shown. The first rod Rl is arranged through the first PI and second P2 piston of the first actuating unit Al along a first longitudinal direction XI. A third rod R3 is arranged through the third P3 and fourth P4 piston of the second actuating unit A2 along a second longitudinal direction X2. The first rod Rl is engagable to the first piston PI by a first clamping body Bl of the first piston PI and engagable to the second piston P2 by a second clamping body B2 of the second piston P2. The third rod R3 is engagable to the third piston P3 by a third clamping body B3 of the third piston P3 and engagable to the fourth piston P4 by a fourth clamping body B4 of the fourth piston P4.

The intermediate member H2 is coupled to the first Rl and the third rod R3 via a wire arrangement W. A first end of the first rod Rl is coupled to a first wire Wl in turn coupled to the intermediate member H2 in a first position. A second end of the first rod Rl is coupled to a second wire W2 in turn coupled to the intermediate member H2 in a second position. The second wire W2 is guided around a first pulley 9. A first end of the second rod R2 is coupled to a third wire W3 in turn coupled to the intermediate member H2 in a first position. A second end of the third rod is coupled to a fourth wire W4 in turn coupled to the intermediate member H2 in a second position. The fourth wire W4 is guided around a second pulley 11.

The first actuating unit Al is coupled to the second actuating unit A2 via a linkage pivot joint arrangement assembly U2.

Fig. 6 illustrates a fluid actuator arrangement 1 according to a sixth example of the invention. There is shown a wire arrangement W guided around a third pulley 13, which wire arrangement W is cou- pled to a third rod R3 of the first actuating unit Al.

Optionally, a rod 32 is coupled between the wire (outgoing from the pulley 13) and the wire coupled to the holding member H.

Fig. 7 illustrates a fluid actuator arrangement 1 according to a seventh example of the invention. A wire arrangement W is guided around a common spherical wire guiding ball 15 arranged to a first actuating unit 1.

Fig. 8a illustrates a fluid actuator arrangement 1 according to an eighth example of the invention. A spring member 17 is coupled to an intermediate member H.

Fig. 8b illustrates a fluid actuator arrangement 1 according to a further example of the invention. The gravity force G influencing an intermediate or holding member H and/or additional member (not shown) coupled to the intermediate or holding member H provides a motion of the intermediate or holding member with rotation "pitch down".

Fig. 9 illustrates a fluid actuator arrangement 1 according to a ninth example of the invention. A first rod Rl comprises a holding member joining end 19 that is coupled to a holding member H. The holding member joining end 19 of the first rod Rl is flexible and tapers in a direction toward the holding member H for providing flexibility of the end of the first rod Rl following the pivoting properties of the holding member. The holding member joining end 19 is coupled to the holding member H via a first universal joint Jl. The flexibility is adaptive to the pitch and yaw motion of the holding member.

Fig. 10 illustrates a fluid actuator arrangement 1 according to a tenth example of the invention. A first rod Rl comprises a holding member joining end 19 that is coupled to a pivot joint arrangement assembly 21 of a linkage member 23 in turn coupled to a holding member H via a first universal joint Jl. The linkage member 23 adaptive to the pitch and yaw motion of the holding member.

Fig. 11 illustrates a fluid actuator arrangement 1 according to an eleventh example of the invention. A first rod Rl comprises a holding member joining end 19 that is rigidly mounted to a flexible operating rod 25 adaptive to the pitch and yaw motion of the holding member.

Fig. 12 illustrates a fluid actuator arrangement 1 according to a twelfth example of the invention. There is shown an assembly of actuating units A1-A7 coupled to each other constituting an interlinked elongated manipulator IEM comprising an end effector 29, which interlinked elongated manipulator IEM is configured for operation in confined spaces S. An elongated holding member HI (may also be called passive member) encompasses electronic devices 31, fluid supply means, valves etc. for operation of the interlinked elongated manipulator IEM. An elongated holding member H2 encompasses other equipment. The size of the respective actuating unit decreases in a direction toward the end effector 29 due to lower requirements for taking up high forces and high moments.

Fig. 13 illustrates a fluid actuator arrangement 1 according to a thirteenth example of the invention. A dual assembly 35 of left and right holding members HL, HR is coupled to a first actuating unit Al A first rod Rl operates the left holding member HL (for pitch motion PM) and a second rod R2 operates a right holding member HR (for pitch motion PM). A third rod (not shown) operates the left holding member (for yaw motion) and a fourth rod (not shown) operates the right holding member (for yaw motion).

Fig. 14 illustrates a fluid actuator arrangement 1 according to a fourteenth example of the invention. A quad joint assembly 41 of holding members H', H", H'", H"" is coupled to a first actuating unit Al. The first holding member H' is coupled to a first rod Rl (for pitch motion) and a second rod R2 (for yaw motion). The second holding member H" is coupled to a third rod R3 (for pitch motion) and a fourth rod R4 (for yaw motion). The third holding member H'" is coupled to a fifth rod R5 (for pitch motion) and a sixth rod R6 (for yaw motion). The fourth holding member H"" is coupled to a seventh rod R7 (for pitch motion) and to an eight rod R8 (for yaw motion).

Fig. 15 illustrates a flow chart of a method according to a fifthteenth example of the invention of moving a first rod and a second rod of a first actuating unit of a fluid actuator arrangement, wherein the first actuating unit comprises a first piston of a first cylinder housing, a second piston of a second cylinder housing, the first rod is engagable to the first piston by a first clamping body of the first piston and is engagable to the second piston (P2) by a second clamping body of the second piston, the second rod is engagable to the first piston by a third clamping body of the first piston and is engaga- ble to the second piston by a fourth clamping body of the second piston, a fluid supply is coupled to the first and second cylinder housing and to the first, second, third, fourth clamping body.

The method shown in Fig. 15 illustrates a first step 1501 comprising the start of the method. A second step 1502 illustrates a method for moving a first rod and a second rod of a first actuating unit of the fluid actuator arrangement. A third step 1503 illustrates a stop of the method. The second step 1502 may comprise the steps of pressurizing the first cylinder housing for moving the first piston, pressurizing the first clamping body for engaging the first piston to the first rod, pressurizing the second cylinder housing for holding the second piston; pressurizing the fourth clamping body for engaging the second piston to the second rod.

The second step 1502 may comprise that the first rod is adapted to translate its longitudinal motion in a first longitudinal direction into a yaw motion of the first holding member relatively the first actuating unit and the second rod is adapted to translate its longitudinal motion in the first longitudinal direction into a pitch motion of the first holding member relatively the first actuating unit.

According to one example of flow chart of a method of the invention, the fluid actuator arrangement comprises a second actuating unit configured to move a third rod and a fourth rod, wherein the sec- ond actuating unit comprises a third piston of a third cylinder housing; a fourth piston of a fourth cylinder housing; the third rod is engagable to the third piston by a fifth clamping body of the third piston and is engagable to the fourth piston by a sixth clamping body of the fourth piston; the fourth rod is engagable to the third piston by a seventh clamping body of the third piston and is engagable to the fourth piston by a eight clamping body of the fourth piston; the fluid supply is coupled to the third and fourth cylinder housing and to the fifth, sixth, seventh and eight clamping body.

The second step 1502 may comprise the steps of pressurizing the third cylinder housing for moving the third piston, pressurizing the fifth clamping body for engaging the third piston to the third rod, pressurizing the fourth cylinder housing for holding the fourth piston, pressurizing the eight clamping body for engaging the fourth piston to the fourth rod. Fig. 16 illustrates a flow chart of a method according to a sixteenth example of the invention for moving a first rod and a second rod of a first actuating unit of a fluid actuator arrangement. The fluid actuator arrangement further comprises a second actuating unit configured to move a third rod and a fourth rod, the second actuating unit comprises a third piston of a third cylinder housing; a fourth piston of a fourth cylinder housing; the third rod is engagable to the third piston by a fifth clamping body of the third piston and is engagable to the fourth piston by a sixth clamping body of the fourth piston; the fourth rod is engagable to the third piston by a seventh clamping body of the third piston and is engagable to the fourth piston by a eight clamping body of the fourth piston; the fluid supply is coupled to the third and fourth cylinder housing and to the fifth, sixth, seventh and eight clamping body,

The fluid actuator arrangement comprises a fifth and a sixth rod each extending through the respective first and second piston the fifth rod is engagable to the first piston by a ninth clamping body of the first piston and is engagable to the second piston by a tenth clamping body of the second piston; the sixth rod is engagable to the first piston by a eleventh clamping body of the first piston and is engagable to the second piston by a twelfth clamping body of the second piston; the fluid supply is coupled to the ninth, tenth, eleventh, twelfth clamping body.

The fluid actuator arrangement further comprises a seventh and an eighth rod each extending through the respective third and fourth piston; the seventh rod is engagable to the third piston by a thirteenth clamping body of the third piston and is engagable to the fourth piston by a fourteenth clamping body of the fourth piston; the eighth rod is engagable to the third piston by a fifthteenth clamping body of the third piston and is engagable to the fourth piston by a sixteenth clamping body of the fourth piston; the fluid supply is coupled to the thirteenth, fourteenth, fifthteenth, sixteenth clamping body.

Step 1601 illustrates start of the method. Step 1602 illustrates pressurizing the third cylinder housing for moving the third piston. Step 1603 illustrates pressurizing the fifth clamping body for engaging the third piston to the third rod. Step 1604 illustrates pressurizing the fourth cylinder housing for holding the fourth piston. Step 1605 illustrates pressurizing the eight clamping body for engaging the fourth piston to the fourth rod. Step 1606 illustrates pressurizing the first cylinder housing for moving the first piston. Step 1607 illustrates pressurizing the ninth clamping body for engaging the first piston to the fifth rod. Step 1608 illustrates pressurizing the second cylinder housing for holding the second piston. Step 1609 illustrates pressurizing the twelfth clamping body for engaging the second piston to the sixth rod. Step 1610 illustrates pressurizing the third cylinder housing for moving the third piston. Step 1611 illustrates pressurizing the thirteenth clamping body for engaging the third piston to the seventh rod. Step 1612 illustrates pressurizing the fourth cylinder housing for holding the fourth piston. Step 1613 illustrates pressurizing the sixteenth clamping body for engaging the fourth piston to the eight rod. In Step 1614 the method is fulfilled and stopped. Fig. 17 illustrates a CPU device 1000 according to one aspect of the invention. The CPU device 1000 may be adapted to a control unit CU of a fluid actuator arrangement 1. The control unit CU is configured to control the moving a first rod l and a second rod R2 of a first actuating unit and to control the moving a third rod R3 and a fourth rod R4 of a second actuating unit providing that the first rod translates its longitudinal motion (in a first longitudinal direction) into a yaw motion of a first holding member relatively the first actuating unit and that the second rod translates its longitudinal motion (in the first longitudinal direction) into a pitch motion of the first holding member relatively the first actuating unit and that the third rod translates its longitudinal motion (in a first longitudinal direction) into a yaw motion of the second holding member relatively the second actuating unit and that the fourth rod translates its longitudinal motion (in the first longitudinal direction) into a pitch motion of the second holding member relatively the second actuating unit.

Preferably, the control unit CU is furthermore configured to control the moving a fifth rod a sixth of the first actuating unit and to control the moving a seventh rod and a eight rod of the second actuating unit providing that the fifth rod translates its longitudinal motion (in the first longitudinal direc- tion) into a yaw motion of a second holding member relatively the first actuating unit and that the sixth rod translates its longitudinal motion (in the first longitudinal direction) into a pitch motion of the second holding member relatively the first actuating unit.

The control unit CU thus comprises the CPU device 1000 of a computer. The CPU device 1000 comprises a non-volatile memory NVM 1020, which is a computer memory that can retain stored infor- mation even when the computer is not powered. The CPU device 1000 further comprises a processing unit 1010 and a read/write memory 1050. The NVM 1020 comprises a first memory unit 1030. A computer program (which can be of any type suitable for any operational data) is stored in the first memory unit 1030 for controlling the functionality of the CPU device 1000. Furthermore, the CPU device 1000 comprises a bus controller (not shown), a serial communication left (not shown) providing a physical interface, through which information transfers separately in two directions. The CPU device 1000 may comprise any suitable type of I/O module (not shown) providing input/output signal transfer, an A/D converter (not shown) for converting continuously varying signals from e. g. a sensor arrangement (not shown) of the pivot joint arrangement is configured for detecting of the angular value of the holding members relatively the actuating units, into binary code suitable for the computer. Other operational data may be actual loads on the end effector, pitch/yaw motion velocity of the holding members etc.

The CPU device 1000 also comprises an input/output unit (not shown) for adaptation to time and date. The CPU device 1000 comprises an event counter (not shown) for counting the number of event multiples that occur from independent events in operation of the fluid actuator arrangement. Furthermore, the CPU device 1000 includes interrupt units (not shown) associated with the computer for providing a multi-tasking performance and real time computing for automatically adapting the speed of the first, second, third piston rods etc. and other features in accordance with programed data.

The NVM 1020 also includes a second memory unit 1040 for external controlled operation. A data medium storing program P may comprise routines for automatically adapting the speed of the common piston body in accordance with the actual fluid pressure and is provided for operating the CPU device 1000 for performing the method. The data medium storing program P comprises a program code stored on a medium, which is readable on the computer, for causing the control unit CU to perform the method.

The data medium storing program P further may be stored in a separate memory 1060 and/or in the read/write memory 1050. The data medium storing program P, in this embodiment, is stored in executable or compressed data format. It is to be understood that when the processing unit 1010 is described to execute a specific function that involves that the processing unit 1010 may execute a certain part of the program stored in the separate memory 1060 or a certain part of the program stored in the read/write memory 1050.

The processing unit 1010 is associated with a data port 999 for communication via a first data bus 1015. The non-volatile memory NVM 1020 is adapted for communication with the processing unit 1010 via a second data bus 1012. The separate memory 1060 is adapted for communication with the processing unit 1010 via a third data bus 1011. The read/write memory 1050 is adapted to communicate with the processing unit 1010 via a fourth data bus 1014. The data port 999 is preferably con- nectable to data links of the control unit. When data is received by the data port 999, the data will be stored temporary in the second memory unit 1040. After that the received data is temporary stored, the processing unit 1010 will be ready to execute the program code, according to the above-mentioned method.

Preferably, the signals (received by the data port 999) may comprise information about operational status of the fluid actuator arrangement, such as operational status regarding the position of the respective rod and/or piston relative each other and relative the respective cylinder housing. The signals may also comprise information about e.g. operational data regarding fluid pressure data and/or load data and/or fluid temperature, etc. According to one aspect, signals received by the data port 999 may contain information about actual angular positions of the actuating units relative each other and relative the holding members.

The received signals at the data port 999 can be used by the CPU device 1000 for controlling and monitoring the speed and/or motion schedule of the respective piston and/or angular adjustments of the respective actuating unit relative each other.

The signals received by the data port 999 can be used for automatically moving the piston between two end positions. The signals can be used for different operations of the fluid actuator arrangement, such as operating the pressurization of each individual clamping body. The information is preferably measured by means of suitable angular sensor arrangements of the fluid actuator arrangement. The information can also be manually fed to the control unit CU via a suitable communication device, such as a computer display or a touchscreen.

The present invention is of course not in any way restricted to the preferred embodiments described above, but many possibilities to modifications, or combinations of the described embodiments, thereof should be apparent to a person with ordinary skill in the art without departing from the basic idea of the invention as defined in the appended claims.

The clamping bodies configured to engage and disengage the respective piston to and/or from the respective rod can be of any suitable number. The fluid actuator arrangement may comprise three or more cylinder housings arranged in each actuating unit, wherein each cylinder housing comprises a respective piston. Preferably, all examples of the invention may involve that the first rod is adapted to translate its longitudinal motion in a first longitudinal direction into a yaw motion of the first holding member relatively the first actuating unit and the second rod is adapted to translate its longitudinal motion in the first longitudinal direction into a pitch motion of the first holding member relatively the first actuating unit.