FiELD OF THE !NVENTIOM

The present invention relaies to a safety system for a robot with one or more arms working to move loads from one position to another, in particular where the task is to stack layers of objects or goods on to pallets or vehicles, or to take objects {i.e. cans or boxes with different contents) from a multitude of positions to one packing position to provide the mix specified by a control program.

BACKGROUND OF THE SNVEOTSGN

The moving of objects from one position to another in a controlled way poses, to some degree, a problem. Many transport options exist today as commercially available products, where the movement and packing operations are manual due to the complexify of handling more than two iypes of objects. Stationary robots are used in situations where the number of objects to be handled is lo and the height of the deposition position is exceeding the human reach.

Such a robot is placed on or above a floor with one or a multitude of conveyer bands or roller tracks situated in such a way that if can move objects (for exampl cans or boxes) from one conveyer band to another. The conveyer bands may transport boxes, pallets or similar collecting containers, and the robot may be used for stacking of such containers up to a certain height. Such a system is described in a prior art application EP2 221 152 At.

Similarly, the robot can be mounted on a movable base plate connected to a rail track on a gantry. The gantry is placed on or above a floor with one or a multitude of conveyer bands or roller tracks situated alongside or perpendicula to the gantry on one o both sides of the gantry in such a way that it can move objects (for example cans or boxes) from one conveyer band to another, for example from a multitude of feeder conveyers with different types of objects to one (or more) collector conveyer(s) with mixed object content, for example on the opposite side o the gantry. The conveyer bands may transport boxes, pallets or similar collecting containers, and the robot may be used for stacking of such containers up to a certain height. Sn such prior art systems, the robot must be surrounded by a fence or a light fence to prevent humans from entering the work zone. The fence is creating problems as work items are not allowed to move in or out of openings in the fence, and the robot wi! stop working if a human activates the fence alarm. As the gantry may have a span across several supply conveyor bands, it will be working inside a large working area, which means there will be parts of this working area, where it will be safe for humans to enter, while the robot is working elsewhere {for example to supply special goods, to correct position for misplaced or faiien-off objects, for exchange of conveyor bands etc).

Sn this situation it is convenient that persons can enter the working space in a safe way. which means the robot must be stopped while the persons are within the active range of the robot, but the robot can go on in its process afte the persons have left the active range. Although there is a significant economic incentive to introduce systems enabling human access to areas inside the working zone where the robot is not presently working, relatively little progress has been made towards creating cost competitive collaborative solutions,

DE 102005003827 A1 discloses a stationary robot working by one or more robot arms to move objects from one or more supply positions to target position(s) with a scanner or sensor attached to a mechanism on or following the robot arm(s), the scanner signal being connected to a control system used for establishing a safe zone around the load attached to the arm(s).

US 2006/0049939 A1 discloses a stationary robot with safety zones adapted to the robot arm movements i such a way as to minimize the safety zone and aliow human access close to the tool attached to the robot arm. SUMMARY OF THE INVENTION

According to the present invention, the safety of persons is provided by a scanner, which scans the active range of the robot below the load, when the robot is working from a gantry. The present invention replaces the fence by ^' creating a safety zone around the robot's load by using a scanner in such a way that work items can move in and out of the zone, but the robot is stopped if a human or any other object is penetrating the zone limit. Sn the present invention, a Sow-cost scanner with a vertically narrow scanner beam width is moved up and down (and horizontally) with the load in such a way that it does not detect the load itself. This is achieved by the scanning plane being kept at a small distance below the load. At the same time, th horizontal scanner field is defining a safety area equal to the movement limits for the robot arm and its load (e.g. a grabber or other tool). As the robot arm moves, the safety area moves with it, thereby allowing people or other objects to enter the work zone outside the safety area without interfering with the load. If the load is carried to a height of 2,5 meters or higher it is considered to be out of reach and therefore safe to move without further safety measures, In a first embodiment, the scanner beam is following the load but scanning under the load, thereby securing that no vehicle or person can enter the safety zone without causing a scanner signal, said signal is then, via a control system, used to slow down or stop the robot motion in a controlled way. The scanner is mounted on a reverse guide rail mechanism using a motor and a toothed rack and pinion transmission (SMC-system) in such a way that the lower end of the rail is moved in the vertical direction at the same rate as the load, using either a counterweight via a wire and pulley system or a constant force spring to ease the load on the motor. This arrangement enables the scanner to move the entire length from the fioor to the upmost position of the load and at the same time allows the space under the gantry to be free for passage of conveyer belts, vehicles or goods while the robot ioad is moving along the gantry.

In this situation it is convenient that persons can enter the working space to correct things or suppl special goods in a saf way, which means the robot must be stopped while the persons are within the active range of the robot, but the robot can go on in its process after the persons have left the active range.

According to the present invention, the safety of persons is provided by a scanner, which scans the active range of the robot below the load, in this way It is secured that persons cannot by mistake "hide" behind a load or a vehicle and go undetected into the robot's work zone.

In a particuiariy important ease the robot is working from a gantry. The robot is mounted on a movable base plate connected to a rail track on the gantry. The gantry is placed on or above a floor with one o a multitude of conveyer bands or ro!ier tracks situated alongside or perpendicular to the gantry on one or both sides of the gantry in such a way that it can move objects (for example cans or boxes) from one conveyer band to another, for example from a multitude of feeder conveyers with different types of objects to one (or more) collector conveyer(s) with mixed object content, for example on the opposite side of the gantry. The conveyer bands may transport boxes, pallets or similar collecting containers, and the robot ma be used for stacking of such containers up to a certain height, in a prior art system the robot must be surrounded by a fence or a light fence to prevent humans from entering the work zone. The fence is creating problems as work items are not allowed to move in or out of openings in the fence. The present invention replaces the fence by creating a safety zone around the robot by using a scanner in such a way that work items can move in and out of the zone, but the robot is stopped if a human or any other object is penetrating the zone limit.

Sn a prior art patent application JP2G10-61772, a stationary scanner is used to detect bodies inside a defined 2-dimensionai horizontal zone using a scanner beam with small vertical width. To allow vehicles to enter the scanned area without being detected, the scanner beam is deflected out of the scanner reception plane by an inclined "mirror" on the front of the vehicle, in this way, the vehicle can enter the safety zone without interfering with the working robot, but other object or persons entering the safety zone will cause the robot to stop working. in a second prior art application DE102012108418, a device comprises Iwo robotic controllers that are attached to a robot. One of two robotic controllers is provided with an additional safety control unit. The additional safety control unit is cross-linked with a safety sensor such as safety laser scanner, in this system, a separate safety system is stopping the work action, when objects move into the safety zone scanned by the scanner.

In the present invention shown in Fig, 1, a scanner (4) with a. small vertical scanner beam width is moved up and down (and horizontally) with the load in such a way that it does no detect the load itself. This is achieved by the scanning plane being kept at a small distance below the load. At the same time, the horizontal scanner field is defining a safety area equal to the movement limits for the robot arm and its ioad (e.g. a grabber o other too!}. When the robot arm moves, the safety area moves with it, thereby allowing people or other object to enter the work zone outside th safety area without interfering with th load. If the load is carried to a height of 2.5 meters or higher it is considered to be out of reach and therefore safe to move without further safety measures.

In a first embodiment shown in Fig, 2c, the scanner beam is following the load but scanning under the load, thereby securing that no vehicles or person can enter the scanned zone without giving a scanner signal, which is used to stop the robot. The scanner {4) is mounted on a vertical guide rail mechanism (5) which is programmed to follow the vertical robot head tool path using a motor and a toothed rack and pinion transmission (7).

Sn a second embodiment shown in Fig. 2a and 2b especially well-suited for use with a robot moving along a gantry (9), the scanner (4) is mounted on a reverse guide rail mechanism (S, 8, 7) in such a way that the lower end of the rail is moved in the vertical direction at the same rate as the load (using a counterweight via a pulley system or a spring to ease the load on the motor). This enables the space under the gantry to be free for passage of conveyer belts, vehicles or goods while the robot load is away from the passageway, In a third embodiment, the scanner (4) can also be placed on the end of the tool hanging low enough to scan a certain distance under the load. In this cas a rail for the scanner can either be avoided or be a small one mounted on the too! so the scanner can pull up to the same height as the tool, allowing the tool to grab toads f mm conveyers or flat surf aces without the scarifier being in the way.

In a preferred embodiment of the present invention there is provided a robot system comprising:

* a robot working by one or more robot arms;

^» a work arrangement in which objects are to be moved from one or more suppl positions in a wo area to target position (s) in a second work area by means of said on or more robot arms;

* a mechanism or fixture (5) arranged to follow the one or more robot arms with load in its movements at a defined distance below the load;

a scanner or sensor (4) which is positioned on said mechanism or fixture (5), and configured with a beam, so as to detect persons or other objects entering the active range of the one or more robot arms with load, said scanner or sensor {4) is mounted on a vertical guide rai! mechanism (6);

* a control system which is programmed with one or more safety range distances of the one or more robot arms with load and which will stop the movement or reduce the velocity of the robot movement when detection of persons or other objects occur;

wherein the beam of the scanner is following the one or more robot arms with load while scanning below the one or more robot arms with load, thereby ensuring that the movement of the robot is stopped or reduced in its movement speed if vehicles or persons enter the active range of the scanned zone; and

wherein the scanner {4) is mounted on a cart {5) and guided by a vertical guide rail (6) attached to a toothed rack and pinion transmission (7, 8} mounted to the base of the robot {1), and using a wire (3) and trolley / pulley (2) connection allowing for doubling the travel ratio of distance and speed,

Sn a further aspect X1 of the present invention there is provided in a robot system provided in a work environment

- A robot system comprising:

A robot working by one or more robot arms

A work arrangement i which objects are to be moved from one or more supply positions in a work area to target position(s) in a second work area by means of said robot arm{$) A mechanism or fixture (3) arranged to follow the robot armf ) with load in its movements af a defined distance below the load

A scanner or sensor (4) which is positioned on said mechanism or fixture (3) in such a way as to detect persons or other objects entering the active range of the robot arm{s) with load

A control system which is prc¾mmmed with the safe range distances of the robot arm{s) wit load and which will stop the movement or reduce the velocity of the robot movement whe detection of persons or other objects occur. Aspect X2; A robot system according to aspect X1 , wherein the robot is mounted on a movable platform moving along a gantry (9), comprising:

A mechanism {2, 3, 5, 6, 7) arranged to folow the robot arm(s) in its (their) movements at a defined distance below th load

Said mechanism arranged in such a way as to allow positioning of conveyor belts, transport vehicles or other objects unde the gantry (9) without danger of collision with said mechanism

A scanner or sensor (4) which is positioned on said mechanism in such a way as to detect persons or other objects entering the active range of the robot arm(s) with load

A control system which is programmed with the safe range distances of the robot arm(s) with load and which will stop the movement or reduce the velocity of the robot movement when detection of persons or othe objects occur.

Aspect X3: A robot system according to aspect X1 and X2, wherein the vertical position of the scanner is variable in relation to the ioad position.

Aspect X4: A robot system according to aspect Χ to X3, wherein the scanner (4) is able to scan a horizontal plane and has defined area limits, where a signal is generated when a object is inside said limits, the area limits being of circuiar, rectangular or other geometrical shapes, said signal to be transmitted to a controller which causes the robot to change speed of movement or to stop, depending on programmed conditions. Aspect XS: A robot system acoofdirsg to Aspect X4, wherein the scanning area limits are variable by pre-programmed conditions, e.g. wide when the robot Is moving in horizontal directions and narrow when moving in vertical direction. Aspect X6: A robot system according to Aspect X4 to X5, wherein the scanner (4) is able to scan multiple area limits, e.g. wide when only a reduction of movement speed is defined, and narrower when a stop of the robot movement is defined.

Aspect X7: A robot system according to Aspect X4 to X6, wherein the scanner (4) is able to scan in a horizontal plane plus to tilt said piane from horizontal to vertical and thereby scan a volume when needed (2 ½ D).

Aspect X8: A robot system according to Aspect X4 to X6, wherein th scanne (4) is able to scan a 3D volume when needed.

Aspect XS: A robot system according to Aspect X1 to X7, wherein the scanner (4) is used to detect the positio of the setting-off surface for the load and ensure safe and accurate set- down through feed-back to the robot control system. Aspect XI 0: A robot system according to Aspect X1 to X7, wherein the scanner (4) is used to detect the position of the gripping surface for the ioad and ensure safe and accurate gripping through feed-back to the robot control system.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 shows the general arrangement of the robot arranged on a gantry. Figure 2 shows details of the first embodiment of the Invention,

Figure 3 shows the emitted warning zones from the safety scanner.

Figure 4 shows the positioning of the warning zones reiative to the robot arms position. Figure 5 shows a scenario of unloading while a person stands underneath.

Figure 6 shows the red warning zone being activated by a person underneath th load,

Figure 7 shows the robot arm unloading onc the person is clea of the warning zone.

Figure 8 shows the robot arm travelling horizontally along with the warning 2©nes. Figure 9 shows the warning zone activating once reaching a person during its horizontal travel

Figure 10 shows the safety scanner mounted on a tool for the robot arm sti!l able to scan underneath the workload Figure 11 shows a diagram explaining how the robot arm and safety scanner should act according to signals received from warning zones.

DETAILED DESCRIPTION OF THE INVENTION

Figure 1 shows the general arrangement of the robot (1, 2} arranged on a gantry (9) and with a sensor or scanner (4) mounted on a guide mechanism (10).

Figure 2a and 2b show the base for the robot (1) with arms and tool holder, the guide rail (6) with cart (5), the (SMC) rack and pinion rail (7) and raii base (8) attached to the robot plinth (1 ), the sensor (scanner) (4), the pulley (2) with the wire (3), the gantry (9) of a first embodiment of the invention, wherein two positions of the sensor or scanner (4) are illustrated.

The wire (3) is fastened through a hole in the plinth (1) and goes over the trolley / pulley (2) and down to the outer rail cart (5) where the safet scanner (4) is mounted. Using the wire {3} and pulley (2) connectio allows for double the travel ratio of distance and speed. Having th SMC rail (7) move up to the same height as the gantry (9) allows having a conveyor or other objects going under the gantry without blocking the robot as it travels along the gantry (9). Figure 2c shows a second embodiment of the invention. If there are no obstacles or conveyors under the gantry (9) then the SMC rail (7) can move aiong the gantry {9), so the SMC rail (7} is mounted directly on the robot base (1 ) and the scanner {4} is then mounted on its cart (8). The SMC rail will then determine the travel velocity and distance.

Robot and scanner collaboration:

Figures 3 and 4 show the warning zones. The scanner (4) is programmed to detect three different warning zones with each their purpose.

Warning zone (11 ) is the yellow zone which is there to warn the robot in case someone or something is nearing its working area and therefore to drop down to half speed to avoid risk of collision, Warning zone (12) is the red zone which is there to warn the robot that someone or something is to dose to its load and causes the robot to stop all motion to avoid danger of collision.

Warning zone (13) is the orange zone is there to warn the robot of someone or something getting too close to the gantry (9) while the robot moves along the gantry. This is to avoid collision with robot and the platform which it is mounted to.

The scanner (4) ensures with the help of the warning zones that the robot can travel and move freel as long as nothing is near it or i its way, Scenario examples:

Figure 5 shows a scenario, when the robot is reaching down to unload or grab a load, the robot arm with load will continue its movement until it reaches the person underneath, unless it is stopped. When the warning zone(s) (11 or 12) reach the person it will activate the robot control system and immediately stop the robots' movement.

Figure 6 shows a scenario where the robot load moves downward and the person touches the red zone (12), which activates the control system and stops the robots' movement for as long as the person is inside the zone. Once the worker has removed himself from the scanner warning area(s) {11 and 12) and no longer stands in the path of the load, the robot can reactivate and automatically resume its operation.

Figure 7 shows a scenario where the robot is able to reach down to the floor while the worker is out of the way .

Figure 8 shows a scenario where a worker happens to be in the robots' working area without paying attention to the robots' movement as it changes pallet position. The warning zone (11) will defect the worker as the robot moves toward him. The signal from the warning zone will then tell the robot to slow down to half speed. The warning zone (12) will detect the worker as the robot moves further toward him. The signal from the warning zone will then tell the robot to immediately stop.

The activatio of the red warning zone (12) ensures that the load and robot will not collide with the inattentive worker. The robot will remai still until the worker gets clear of the scanners' warning zones (11 and 12) but will resume its operation once the path again is clear. Figure 9 shows a scenario In which the red zone (12) is activated and thereby forcing the robot to stop and stay still for as long as the worker is present in the warning zone.

Figure 10 shows a scenario with an alternative mounting of the scanner (4), Given the scanner (4) is capable of projecting a plane in at least a 180 degree angle, th scanner {4} can alternatively be mounted on the end of the tool (14) (e.g. a grabbing tool) and still use the same warning zones to secure workers and robot.

Use of scanner functions: There are various ways to use the functions of the scanner depending o the scenario the user prefers. in case the user wishes the robot arm to move along the gantry {9} as soon as the scanner (4) is clear of obstacles along the way, a wider yellow warning zone (11) can be implemented to ensure that the robot will reduce sis speed to half before the obstacle reaches the red warning 2one (12).

So case that the gantr (9) has one or both ends up against a wall, the orange warning zone (13) can be reduced to shorter length along the gantry (9) and be replaced wit a yellow warning zone (11) to reduce its speed to half before reaching the orange zone (13). This will also ensure that the robot can make use of the fuii length of the gantry (9) without the waiis at the end blocking the orange warning zone (13) causing the robot to stop ai! movement.

Depending on the programming of the scanner (4), various warning zones couid be implemented according to the robots' movement. For example it can have wider zones. (1 , 2) during horizontal movement along the gantry (9) and slimmer zones (1 , 2} when moving vertically.

Assuming the scanner projecting plane can be tilted up and down to have a warning zone in what is referred to as 2.5 dimensions, as the scanner (4) moves slower than the robot, it can be capable of compensating by changing the angle of its projected warning zone(s), thereby reducing its necessary travel distance and check for persons or objects below the scanner height.

Assuming the technology is available for safety purposes a scanner capable of scanning 3D volumes and creating a 3 dimensional warning zone can be mounted on the robot providing better detection of persons or obstacles.

Figure 11 shows in a diagram how the safety controller needs to interpret signals from the scanner and how to act upon them to make the work area safe.