Technical Field

The present invention relates to a limb por tion, a limb comprising the limb portion, a legged robot comprising the limb, and a first and a second method for cooling the limb portion.

Background Art

Robots are designed for a specific application but can further conduct specific missions or take over a specific task. In particular robots can comprise one or more limb such as one or more arms and/or one or more legs to be able to conduct such a specific task or mission.

The limbs are often designed to mimic the move ment of a human or animal limb. To design a robot limb in a way to have multiple degrees of movement, it consist of multiple limb portions that are connected with each other to form a well manoeuvrable and movable limb that is able to conduct even complex movement patterns.

Document Zhong et al., "Analysis and Research of Quadruped Robot Leg's: A comprehensive Review", Int. J. of Adv. Robotic Systems, vol. 16, pages 1-15, discloses a quadruped robot, wherein each limb of the robot comprises multiple limb portions.

Tasks assigned to such a robot might require that the robot enters rough terrain where it is exposed to heat, water and dirt, or an explosive environment.

The often complex design of the limbs compris ing electronic connections, chips and logic circuits might be very sensitive to such an environment. In particular if logic circuits or cables are exposed to violent shocks or extreme heat, this can lead to damages of the limb or in the worst case to the failure of the whole robot. Disclosure of the Invention

The problem to be solved by the present inven tion is therefore to provide a design for a limb portion that protects the limb portion against damages during a mission.

The problem is solved by the subjects of the independent claims concerning a first, a second, a third a fourth, and a fifth aspect of the invention.

Unless otherwise stated, the following defini tions shall apply in this specification:

The terms "a", "an", "the" and similar terms used in the context of the present invention are to be construed to cover both the singular and plural unless otherwise indicated herein or clearly contradicted by the context. Further, the terms "including", "containing" and "comprising" are used herein in their open, non-limiting sense. The term "containing" shall include both, "compris ing" and "consisting of".

Advantageously, the term "arranged in a line" refers to an arrangement, wherein a line can be drawn through all parts in a three dimensional room.

Advantageously, the term "torso of a robot" or "torso" refers to a main body of a robot comprising the logic components for controlling the robot and wherein the limb section or limb is attached to the torso. In partic ular, wherein the torso might comprise multiple limbs, e.g. for a quadruped robot.

These definitions are not limiting the scope of protection.

A first aspect of the invention concerns a limb portion for a robot comprising a first actuator, a second actuator and a housing. The housing encloses, in particular only partially encloses, a first heat source of the first actuator and a second heat source of the second actuator. Furthermore, the housing forms a cavity.

In addition, the housing comprises a first air opening, in particular an air inlet, and a second air open ing, in particular an air outlet, for an airstream to vent the cavity.

The first actuator is adapted to pivot the limb portion around a first pivot axis and to pivotably couple it to a first further section of the robot limb.

The second actuator is adapted to pivot the limb portion around a second pivot axis and to pivotably couple it to a second further section of the robot limb.

In an advantageous embodiment of the invention, the cavity thermally couples to the first heat source of the first actuator and to the second heat source of the second actuator.

In a further advantageous embodiment of the invention, the housing forms further a second cavity, wherein the housing comprises a third air opening and a fourth air opening for an airstream to vent the second cavity. In particular in this embodiment, the cavity ther mally couples to the second heat source and the second cavity thermally couples to the first heat source. In par ticular, in such an embodiment, the cavity and the second cavity are separated by a separating wall. In particular, the separating wall is arranged essentially in the middle of the limb portion.

Advantageously, the actuators are adapted to mechanically and/or electrically couple to another section of the limb, another limb portion, or to the robot torso.

The limb portion is advantageously a thigh of the robot limb, coupled with the first actuator to a shank and with the second actuator to a hip abduction adduction.

In particular, the cavity refers to space within the limb portion that is enclosed by a housing. The housing might be fully enclosing the cavity or might have openings. In particular, the housing might comprise multi ple housing parts that form a cavity, wherein the cavity does not need to be fully enclosed by the multiple housing parts.

In an advantageous embodiment of the invention, the first heat source of the first actuator is a first electric drive and/or the second heat source of the second actuator is a second electric drive that generates heat. Since the heat sources are in thermal connection with the cavity, the air within the cavity heats up.

Therefore, the first air opening and the second air opening allow to vent the cavity with air that means that the air within the cavity is exchanged for cooling down the air temperature within the cavity and therefore cooling the first and second heat source.

Advantageously, the first air opening is ar ranged close to the first actuator and the second air open ing is arranged close to the second actuator.

In a further advantageous embodiment, the first air opening, the first heat source, the second heat source and the second air opening are aligned in a line.

In a further advantageous embodiment of the invention, the first pivot axis is arranged parallel to the second pivot axis.

In a further advantageous embodiment of the invention, a first rotation direction of the first pivot axis and a second rotation direction of the second pivot axis are directing in opposite directions.

In a further advantageous embodiment of the invention, the first heat source and/or the second heat source is at least one cooling rib thermally connected to a stator, a circuitry, and/or a gear box of the respective first and/or second electric drive.

In an advantageous embodiment of heat source, the first and/or second electric drive comprises cooling ribs to transport the heat away from the hot parts of the respective electric drive. The cooling ribs are the heat sink of the electric drive respectively the actuator.

In an advantageous embodiment of the invention, first cooling ribs of the first actuator and/or second cooling ribs of the second actuator are arranged within the airstream between the first air opening and the second air opening.

In particular, the cooling ribs are oriented in a direction of the airflow. Therefore, advantageously, the first air opening, the first cooling ribs and/or the second cooling ribs and the second air opening are arranged in a line.

In a further advantageous embodiment of the invention, at least one fan is arranged within the cavity to actively vent the cavity.

In particular, the at least one fan might be a pull fan for pulling the air from the first air opening into the cavity. The at least one fan is advantageously arranged between the first actuator and the second actua tor, advantageously closer to the first actuator and/or closer to the first air opening.

In a further embodiment, the at least one fan might be a push fan for pushing the air out of the cavity towards the second air opening , in particular towards an air outlet. The at least one fan is advantageously arranged between the first actuator and the second actuator, advan tageously closer to the second actuator and/or closer to the second air opening.

In a further advantageous embodiment of the invention, a second fan is arranged within the cavity. Advantageously, in such an embodiment, the at least one fan is a pull fan for pulling the air into the cavity and the second fan is a push fan for pushing the air out of the cavity.

In a further advantageous embodiment of the invention, a second fan is arranged within the second cav ity, to actively vent the second cavity. In a further advantageous embodiment of the invention, the cavity might comprise a temperature sensor for measuring a temperature T _max , for controlling the over heating within the cavity. In particular, the fan is only activated, if the temperature within the cavity exceeds a certain threshold temperature T _max , with T _max > 40°, in par ticular with T _max ³ 50°.

In a further advantageous embodiment of the invention, the limb portion comprises further a third ac tuator coupled to the second actuator.

In particular, the second and/or third actuator is mechanically and/or electrically coupleable to a torso of the robot.

In partiuclar, the first, second, and/or third actuator are torque density proprioceptive actuators. Each actuator integrates a drive and a gear. Each actuator has appropriate torque output and high efficiency and enables force control in all applications.

In a further advantageous embodiment of the invention, the first actuator is pivotably coupled to a shank.

In particular, such a coupling might be done by means of the knee flexion extension joint mechanism. In particular, the knee joint between the first actuator and the shank is driven by the actuator and knee flexion ex tension joint mechanism.

In particular, a coupling mechanism is designed to move the first further limb section, in particular a shank, with an angle from 0 to 360°.

In particular, the knee flexion extension joint mechanism supports a knee-like movement of the shank in relationship to the first actuator.

In a further advantageous embodiment of the invention, the second actuator together with a second link age mechanism is a hip flexion extension, in particular of a legged robot or a quadruped robot. In a further advantageous embodiment of the invention, the second actuator is pivotably coupled to the third actuator, in particular by means of a hip flexion extension mechanism. In particular, the abduction/adduc- tion joint of the hip joint is driven by the actuator and the hip flexion extension mechanism.

Advantageously, the hip flexion extension mechanism allows a hip-like movement, meaning a movement with multiple degrees of freedom, of the second actuator versus the third actuator or the robot torso respectively.

In a further advantageous embodiment of the invention, at least one cable that connects the first ac tuator to the second actuator or to the torso of the robot passes through the cavity. In particular, all cables that are connected to the first actuator pass through the cav ity.

In a further advantageous embodiment of the invention, the first actuator comprises a first tubular opening extending along the first pivot axis. The tubular opening of the first actuator is in particular adapted to serve as a first cable duct.

The second actuator comprises a second tubular opening extending along the second pivot axis. The tubular opening of the second actuator is in particular adapted to serve as a second cable duct.

In particular, the first cable duct is adapted to feed through at least one cable of the first further section that connects the first further section to the torso of the robot via the first tubular opening, the cav ity, and the second tubular opening.

In particular, the second tubular opening is adapted to feed through at least one cable that connects the first actuator and/or a first further section to the robot torso or to the third actuator.

In an advantageous embodiment of the invention, the at least one cable that connects the first actuator and/or the first further section to the robot torso passes the cavity and the second cable duct.

Advantageously, one or more power cables con nect the limb portion and/or the limb directly or indi rectly to a power source of the torso.

Further advantageously, one or more logic ca bles connect the limb portion and/or the limb directly or indirectly to a logic processing unit of the torso.

In a further advantageous embodiment of the invention, at least one first cable, in particular a power cable, for connecting the first actuator to the torso of the robot, passes through the cavity and through the second cable duct.

In a further advantageous embodiment of the invention, at least one second cable, in particular a power cable, for connecting the second actuator to the torso of the robot, passes through the second cable duct.

In a further advantageous embodiment of the invention, an at least one third cable, in particular a logic cable, for connecting the first actuator to the sec ond actuator, passes through the cavity.

In a further advantageous embodiment of the invention, an at least one fourth cable, in particular a logic cable, for connecting the second actuator to the third actuator or to the torso of the robot, passes through the second cable duct.

A second aspect of the invention refers to a limb of a robot. The limb comprises a limb portion accord ing to a first aspect of the invention, a first further limb section and a second further limb section.

Advantageously, the limb portion is a thigh.

Advantageously, the first further limb section is a shank, pivotably coupled with a proximal end to the thigh by means of the first actuator or the knee flexion extension respectively. Advantageously, the second further limb sec tion is a third actuator, in particular a hip abduction aduction, coupled to the thigh by means of the second ac tuator or the hip flexion extension respectively.

The abduction/adduction joint of the hip joint is driven by the actuator and a linkage mechanism, which enables the robot to realize the swinging and twisting motion.

In a further advantageous embodiment of the invention according to the second aspect, the limb com prises a hoof that is arranged at a distal end of the shank, opposite to the proximal end of the shank.

A third aspect of the invention refers to a legged robot comprising a limb according to the second aspect, in particular comprising four limbs according to the second aspect.

A fourth aspect of the invention refers to a method for cooling the limb portion according to the first aspect of the invention. The method comprises the step of activating the at least one fan only if a temperature sen sor arranged within the cavity measures a temperature T _max > 40°C, in particular T _max ³ 50°C.

In a further advantageous embodiment, if the fan and the second fan are arranged within one cavity, the method comprises the step of activating the second fan only if T _max > 100°C.

In particular, if the at least one fan is ar ranged within a first cavity and the second fan is arranged within the second cavity, the method comprises the steps of activating the at least one fan and/or second fan inde pendently from each other if a temperature sensor in the cavity or second cavity measures a a temperature T _max > 40°C, in particular T _max > 50°C. A fifth aspect of the invention refers to a method for cooling the limb section according to the first aspect of the invention, wherein the at least one fan is arranged close to the first actuator and the second fan is arranged close to the second actuator. The method comprises the steps of activating the at least one fan 410 if a first temperature sensor close to the first actuator measures a temperature T _max ³ 40°C, and/or activating the second fan 420 if a second temperature sensor close to the second actuator measures a temperature T _max ³ 40°C, in particular T _max > 50°.

Other advantageous embodiments are listed in the dependent claims as well as in the description below.

Brief Description of the Drawings

The invention will be better understood and objects other than those set forth above will become ap parent from the following detailed description thereof. Such description makes reference to the annexed drawings, wherein:

Fig. la shows a schematic cross section of a limb portion according to an embodiment of the first as pect of the invention;

Fig. lb shows a schematic cross section of a further limb portion according to a further embodiment of the first aspect of the invention;

Fig. 2 shows a schematic cross section of a limb portion according to a further embodiment of the first aspect of the invention;

Fig. 3a shows a schematic view of a limb por tion according to a further embodiment of the inventions wherein a housing that covers the cavity is removed, Fig. 3b shows a schematic view of a limb por tion according to a further embodiment of the invention wherein the housing for covering the cavity is in place;

Fig. 4a shows a schematic view of a limb por tion according to a further embodiment of the inventions wherein a housing that covers the cavity is removed,

Fig. 4b shows a schematic view of a limb por tion according to a further embodiment of the invention wherein the housing for covering the cavity is in place;

In addition, Fig. 4a and 4b show an embodi ment according to the second aspect of the invention;

Modes for Carrying Out the Invention

Fig. la shows a schematic cross section of a limb portion 1000 according to an embodiment of the in vention. The limb portion 1000 comprises a first actuator 1, a second actuator 2, and a housing 4.

The first actuator 1 is adapted to pivotably couple with a first further limb section. The second ac tuator 2 is adapted to pivotably couple to a second fur ther limb section.

The housing 4 encloses a first heat source 10 of the first actuator 1 and a second heat source 20 of the second actuator 2.

In the embodiment as shown in Fig. la, the housing 4 comprises three parts that form the cavity 40.

The housing 4 forms a cavity 40 that ther mally couples to the first heat source 10 of the first actuator 1 and to the second heat source 20 of the second actuator 2.

The housing 4 comprises further an first air opening 41, in particular an air inlet, and a second air opening 42, in particular an air outlet, for an airstream to vent the cavity 40. Advantageously, a first pivot axis 100 of the first actuator 1 is arranged parallel to a second pivot axis 200 of the second actuator.

Further advantageously, a first rotation di rection of the first pivot axis 100 and a second rotation direction of the second pivot axis 200 are directing in opposite directions.

In an advantageous embodiment of the embodi ment, the first actuator 1 is a first electric drive and/or the second actuator 2 is a second electric drive.

In a further advantageous embodiment of the invention, the first heat source 10 and/or the second heat source 20 is one or more cooling rib thermally con nected to a stator, a circuitry, and/or a gearbox of the respective first/and or second electric drive. In partic ular, the first 10 and/or second 20 heat source are cool ing ribs arranged on the surface of a first 1 and/or sec ond 2 actuator respectively electronic drive.

Fig. lb shows a schematic of a cross section according to a further embodiment of the limb portion 1000. The housing 4 forms further a second cavity 40', wherein the housing comprises a third air opening 43 and a fourth air opening 44 for an airstream to vent the sec ond cavity 40'. In particular the cavity 40 thermally couples to the second heat source 20 and the second cav ity thermally couples to the first heat source 10.

As shown in Fig. lb, the second air opening 42 for this embodiment is arranged in center region of the limb portion. A separating wall 444 separates the first cavity 40 from the second cavity 40'.

In an advantageous embodiment, the limb por tion comprises a fan 410 arranged within the first cavity 40 to actively vent the first cavity 40, and/or comprises a second fan 420 arranged within the second cavity 40' to actively vent the second cavity 40'. Fig . 2 shows a schematic cross section of a limb portion 1000 according to a further embodiment of the invention.

In addition, to the features as described for Fig. la, the limb section 1000 comprises further at least one fan 410 that is arranged within the cavity 4. The at least one fan 410 is advantageously a pull fan for pull ing air into the cavity 4 or a push fan for pushing air out of the cavity 4.

Advantageously, the embodiment comprises fur ther a second fan 420. In an advantageous embodiment of the invention, the at least one fan 410 is a pull fan for pulling air into the cavity 4 and the second fan 420 is a push fan for pushing air out of the cavity 4.

Advantageously, the embodiment in Fig. 2 com prises further a third actuator 3. The second actuator 2 pivotably couples to third actuator 3.

In particular, the second 2 and/or third 3 actuator is adapted to mechanically and electrically cou ple to a torso of the robot 1001.

In particular, the embodiment of the limb section 1000 as shown in the figure can further comprise a temperature sensor arranged within the cavity 40. In particular, the at least one fan 410 arranged within the cavity 40 is only activated if the temperature in the cavity 40 reaches a certain temperature T _max with T _max ³ 40°C, in particular T _max > 50°C.

Further advantageously, the second fan 420 is only activated if T _max > 100°C.

In a further advantageous embodiment of the invention, the at least one fan is arranged close to the first actuator and the second fan is arranged close to the second actuator. The at least one fan is activated if a first temperature sensor close to the first actuator 1 measures a temperature T _max > 40°C, and/or the second fan 420 is activated, if a second temperature sensor close to the second actuator 2 measures a temperature T _max ³ 40°C, in particular T _max ³ 50°.

Fig . 3a shows a schematic of a limb portion 1000 according to a further embodiment of the invention, wherein a housing that forms the cavity and comprises the first air opening 41 and the second air opening 42, is removed. The limb portion 1000 comprises the first actua tor 1 and the second actuator 2 with the corresponding first 10 and second 20 heat sources.

Cooling ribs that correspond to the first heat source 10 of the first actuator 1 and cooling ribs that correspond to the second heat source 20 of the sec ond actuator 2 are visible.

In a further advantageous embodiment of the invention, the first actuator 1 comprises a tubular open ing extending along the first pivot axis 100. In particu lar, the opening is adapted to serve as a first cable duct 110.

In a further advantageous embodiment of the invention, the second actuator 2 comprises a second tubu lar opening extending along the second pivot axis 200. In particular, the second opening is adapted to serve as a second cable duct 210.

Fig . 3b shows the embodiment of Fig. 3a with a housing to build the cavity 3.

Under the housing 4, as shown in Fig. 3a at least one cable 61 that connects to the first actuator 1 passes through the cavity 40.

Advantageously, at least one first cable 61, in particular a power cable, for connecting the first ac tuator 1 to the robot torso 1001 passes through the cav ity 40 and through the second cable duct 210. Further advantageously, at least one second cable 62, in particular a power cable, adapted for con necting the second actuator 2 to the robot torso 1001, is passes through the second cable duct 210.

Further advantageously, at least one third cable 63, in particular a logic cable, for connecting the first actuator 1 to the second actuator 2, passes through the cavity 40.

Further advantageously, at least one fourth cable 64, in particular a logic cable, adapted for con necting the second actuator 2 to the third actuator 3 or to the robot torso 1001, passes through the second cable duct 210.

Fig . 4a shows a schematic of a limb portion 1000 according to a further embodiment of the invention, wherein a housing that forms the cavity and comprises the first air opening 41 and the second air opening 42, is removed. The limb portion 1000 comprises the first actua tor 1 and the second actuator 2 with the corresponding first 10 and second 20 heat sources.

Cooling ribs that correspond to the first heat source 10 of the first actuator 1 and cooling ribs that correspond to the second heat source 20 of the sec ond actuator 2 are visible.

Advantageously, the first actuator 1 pivot ably couples to a shank 5, in particular by means of a knee flexion extension mechanism 51. The knee flexion ex tension mechanism 51 supports a knee-like movement of the shank 5 in relationship to the first actuator 1.

Further advantageously, the second actuator 2 pivotably couples to the third actuator 3 by means of a hip flexion extension mechanism 31. The hip flexion ex tension mechanism 31 supports a hip-like movement of the third actuator 3 in relationship to the second actuator 2. Fig . 4b shows the embodiment of Fig. 4a with a housing 4 to build the cavity 3.

Under the housing 4, as shown in Fig. 4a at least one cable 61 that connects to the first actuator 1 passes through the cavity 40.

Advantageously, at least one first cable 61, in particular a power cable, for connecting the first ac tuator 1 to the robot torso 1001 passes through the cav ity 40 and through the second cable duct 210.

Further advantageously, at least one second cable 62, in particular a power cable, for connecting the second actuator 2 to the robot torso 1001, passes through the second cable duct 210.

Further advantageously, at least one third cable 63, in particular a logic cable, for connecting the first actuator 1 to the second actuator 2, passes through the cavity 40.

Further advantageously, at least one fourth cable 64, in particular a logic cable, for connecting the second actuator 2 to the third actuator 3 or to the robot torso 1001, passes through the second cable duct 210.

Advantageously, the at least one first cable 61 and the at least one second cable 62 are connected to a main body feedthrough 1002 arranged within the robot torso 1002.

In particular, an at least one fifth cable 65, in particular comprising a power connection and a logic connection, from the third actuator 3 connect to the main body feedthrough 1002.

The embodiment as shown in Fig. 4b corre sponds further to an embodiment according to the second aspect of the invention, an embodiment of a limb of a ro bot 1100. The limb 1100 comprises the limb portion 1000 according to a first aspect of the invention, wherein the limb portion 1000 is in particular a thigh. In addition, the limb 1100 comprises a first further limb section, in particular a shank 5, coupled with a proximal end to the limb section. In particular, the shank 5 is coupled to the limb section 1000 by means of a knee flexion exten sion joint mechanism 51. The limb 1100 further comprises a second fur ther limb section, in particular a third actuator 3 cou pled to the second actuator 2. In particular, the third actuator 3 is coupled to the second actuator 2 by means of a hip flexion extension mechanism 31. A legged robot comprises at least one limb according to the second aspect of the invention. In par ticular, a legged robot might comprise a robot torso 1001 and one limb 1100, as shown in Fig. 4a and Fig. 4b.

Reference List

First actuator 1

First heat source 10

First pivot axis 100

First cable duct 110

Limb portion 1000

Robot torso 1001

Limb of a robot 1100

Second actuator 2

Second heat source 20

Second pivot axis 200

Second cable duct 210

Third actuator 3

Hip flexion extension mechanism 31

Housing 4

Cavity 40

First air opening 41

At least one fan 410

Second air opening 42

Second fan 420

Separation wall 444

Shank 5 Hoof 50 Knee flexion extension joint mechanism 51 At least one first cable 61 At least one second cable 62 At least one third cable 63 At least one fourth cable 64