Movement control of robot traveling on track
Patent Information
- Application Number
- JP2024229912
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2016-11-02
- Filing Date
- 2024-12-26
- Publication Date
- 2025-05-02
AI Technical Summary
The prior art is difficult to maintain the steady movement of the remotely controlled robot along the track during movement, especially when the wheels are driven independently, which is prone to uneven movement due to inconsistent rotation speeds.
By setting up a main controller and local controller in the robot, monitoring the speed and angle bits of each wheel with the speed and angle bit sensor, setting the speed drive sequence of each pair of wheels to ensure smoothness during the movement from the start point to the end point.
It is achieved to maintain the smooth movement of the robot along the track during the movement from the starting point to the end point, and avoid the unstable problem caused by inconsistent wheel rotation speed.
Smart Images
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Abstract
Description
[Technical field]
[0001] The present invention relates to a teleoperated robot that moves on a track laid on a frame structure, and more specifically to a method and controller for controlling each wheel and synchronizing pairs of wheels of the robot in order to move it smoothly from a start position to a stop position relative to the frame structure. [Background technology]
[0002] Remotely operated vehicles or robots for picking up storage containers from a storage system are known. A detailed description of a related prior art storage system is presented in EP1037828B1, and details of a prior art vehicle suitable for such a storage system are disclosed in detail in Norwegian Patents NO317366B1 and WO2015193278A1. Such prior art storage systems comprise a three-dimensional storage grid containing storage containers stacked on top of each other to a certain height. The storage grid is usually constructed as an aluminium row interconnected by a top rail or track on which a number of remotely operated vehicles or robots are arranged to move laterally. Each vehicle is equipped with a motor for moving the vehicle from one position to another and for driving a lifting device adapted to pick up, transport and place the containers stored in the storage grid. A power supply provides power to the motors and drives provided in the vehicle, and is, for example, a rechargeable battery. The vehicle communicates with the control system, typically via a wireless link, and can be recharged at a charging station when required.
[0003] The rotation of the wheels may be driven by belts connected to the wheels or by individual drive means located on or at least partially within the wheels. A final embodiment would provide a responsive robot with a high degree of control of acceleration and deceleration between start and stop positions.
[0004] When the wheels of a robot moving on a straight track are individually controlled and operated, they must be controlled as if they were one entity in order to move the robot in a steady motion without driving the robot out of its lead angle.
[0005] Ideally, wheels of similar size would rotate at the same speed as the robot moves. However, there are several factors that can contribute to different rotational speeds for the wheels when each wheel is driven separately. Such factors can be spin, skidding, and different loads on the wheels. When this occurs, the robot's movement will not be smooth and may be driven out of the lead angle.
[0006] It is therefore an object of the present invention to provide a method and device for optimal control of the movement of a robot, to move it smoothly from a start position to a stop position on a track, regardless of any disturbances that may occur with respect to the wheels as they rotate on the track. This is achieved by setting a velocity drive sequence for a controller controlling each wheel of the robot, which synchronizes pairs of wheels according to the velocity drive sequence to move the robot smoothly from a start position to a stop position. [Prior art documents] [Patent documents]
[0007] [Patent Document 1] European Patent No. 1037828 [Patent Document 2] Norwegian Patent No. 317366 [Patent Document 3] International Publication No. 2015193278 Summary of the Invention [Means for solving the problem]
[0008] The invention is defined by a method for controlling the movement of a robot from a start position to a stop position, the robot moving on a track laid on a frame structure forming a grid, the robot having pairs of wheels controlled by a local controller connected to individual drive means for each wheel.
[0009] The method is characterized by monitoring each wheel using speed and angular position sensors connected to a local controller controlling a pair of wheels, and comprises the following steps: receiving a start position and a stop position of the robot; - receiving the current speed and angular position of each wheel from a local controller; - receiving a global position of the robot relative to a frame structure; - setting an individual velocity drive sequence for each pair of wheels based on the current velocity and angular position of each wheel, the current global position of the robot, and the start and stop positions of the robot; - transmitting a speed drive sequence to each of the local controllers for controlling the acceleration and deceleration of each pair of wheels; - repeating the above steps to control the movement of the robot from a start position to a stop position; is implemented in a master controller that communicates with each of the local controllers.
[0010] Further features of the method are defined in the dependent claims.
[0011] The invention is further defined by a master controller for controlling the movement of a robot from a start position to a stop position, the robot moving on a track laid on a frame structure forming a grid, the robot having pairs of wheels controlled by local controllers connected to individual drive means for each wheel, the master controller is connected to a local controller controlling each pair of wheels, the local controllers providing the master controller with the speed and angular position of each wheel by means of speed and angle sensors connected to the local controllers, the master controller: input means for receiving the start and stop positions of the robot and the current speed and angular position of each wheel, provided by a local controller; - input means for receiving a global position of the robot relative to the frame structure; - calculation means for setting an individual speed drive sequence for each pair of wheels based on the current speed and angular position of each wheel, the current global position of the robot, and the start and stop positions of the robot; - output means for transmitting a speed drive sequence to each of the local controllers controlling the acceleration and deceleration of each pair of wheels; Equipped with.
[0012] Further features of the master controller are defined in the dependent claims. The present invention provides, for example, the following: (Item 1) A method for controlling the movement of a robot 50 from a start position to a stop position, said robot 50 moving on a track 20 laid on a framework forming a grid 40, said robot 50 having individual drive means Drive 1 , Drive 2 , Drive 3 , Drive 4 The local controller connected to 1-2 , Controller 3-4 Controlled by the wheel pair W 1-2and W 3-4 having Wheel Pair W 1-2 and W 3-4 The above local controller 1-2 , Controller 3-4 The present invention is characterized in that each wheel 60 is monitored using speed and angular position sensors connected to the receiving the start and stop positions of said robot 50; - The current speed and angular position of each wheel 60 is transmitted to the local controller 1-2 , Controller 3-4 receiving from - receiving the position of said robot 50 relative to said frame structure; - Calculate the speed and angular position of each pair of wheels W based on the current speed and angular position of each wheel 60, the current position of the robot 50, and the starting and stopping positions of the robot 50. 1-2 and W 3-4 For the speed drive sequence V seq1-2 , V seq3-4 setting - each pair of wheels W 1-2 and W 3-4 In order to control the acceleration and deceleration of seq1-2 , V seq3-4 The above local controller 1-2 , Controller 3-4 and transmitting the repeating the above steps to control movement of said robot 50 from said start position to said stop position. However, the above local controller Controller 1-2 , Controller 3-4 The method is implemented in a master controller in communication with each of the (Item 2) 2. The method of claim 1, wherein the position of the robot 50 is a global x,y position of the robot 50 provided by external tracking of the robot 50 relative to a track. (Item 3) 2. The method of claim 1, wherein the position of the robot 50 is an absolute local position of the robot 50 relative to the track, the local position being provided by a tracking sensor included within the robot 50. (Item 4) The method of claim 1, wherein a velocity drive sequence defines an acceleration for moving the robot 50 from a start position, a deceleration for moving the robot 50 toward a stop position, and a constant velocity for moving the robot 50 between the start position and the stop position. (Item 5) Each local controller 1-2 , Controller 3-4 If the current speed of one wheel 50 deviates from the set speed of the wheel pair set by the speed drive sequence, the wheel pair W 1-2 and W 3-4 The method according to any of the preceding claims, further comprising adjusting the speed of one of the wheels 60. (Item 6) 13. The method of any preceding claim, wherein the velocity drive sequence is transmitted at a predetermined rate. (Item 7) 2. The method of claim 1, wherein the velocity actuation sequence comprises different start and stop positions according to a route followed by the robot 50. (Item 8) A master controller for controlling the movement of a robot 50 from a start position to a stop position, said robot 50 moving on a track 20 laid on a framework forming a grid 40, said robot 50 having individual drive means Drive 1 , Drive 2 , Drive 3 , Drive 4 Local Controller connected to Controller 1-2, Controller 3-4 Controlled by the wheel pair W 1-2 and W 3-4 having The master controller controls each pair of wheels W 1-2 and W 3-4 The above local controller 1-2 , Controller 3-4 The local controller is connected to 1-2 , Controller 3-4 The above local controller Controller 1-2 , Controller 3-4 , providing the speed and angular position of each wheel 60 to the master controller, which in turn - the start and stop positions of the robot 50 and the local controller 1-2 , Controller 3-4 input means for receiving the current speed and angular position of each wheel 60 provided by input means for receiving the position of said robot 50 relative to said frame structure; - Calculate the speed and angular position of each pair of wheels 60 based on the current speed and angular position of each wheel 60, the current position of the robot 50, and the starting and stopping positions of the robot 50. 1-2 and W 3-4 For the speed drive sequence V seq1-2 , V seq3-4 A calculation means for setting - Each pair of wheels 60W 1-2 and W 3-4 In order to control the acceleration and deceleration of seq1-2 , V seq3-4 The above local controller 1-2 , Controller 3-4 and an output means for transmitting the A master controller comprising: (Item 9) 9. A controller as described in item 8, characterized in that it is connected to a tracking sensor provided in the robot 50. (Item 10) 10. The controller according to item 8 or 9, characterized in that it is embodied in the robot 50. (Item 11) A software program product which, when executed by a processor, performs the methods described in items 1-7. [Brief description of the drawings]
[0013] The present invention will now be described with reference to the figures. [Figure 1] FIG. 1 shows a section of a storage system in which several robots are arranged directly above individual storage rows. [Diagram 2] FIG. 2 shows an example of a teleoperated robot with a set of individually driven wheels. [Diagram 3] FIG. 3 shows an overview of the master and local controllers for controlling the pairs of wheels of the robot. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0014] The present invention is defined by a method and controller for controlling each wheel and synchronizing pairs of wheels of a robot to move smoothly from a start position to a stop position. Controlled smooth movement of the robot is important especially when the robot moves on a track to move efficiently from one point to another while avoiding movement out of lead angle. Figures 1 and 2 illustrate a robot moving on a track on top of a storage system.
[0015] 1 shows a section of a storage system 10 in which several teleoperated robots 50 are arranged directly above individual storage rows 30 created by a framework that creates a receptacle storage grid 40. The upper portion of the receptacle storage grid 40 includes a dedicated support track 20 for the robots 50 to travel on. The robots 50 are configured to move on the tracks 20 in the x and y directions to receive storage receptacles from the storage rows 30 within the receptacle storage grid 40.
[0016] 2 shows an embodiment of a teleoperated robot 50. The robot 50 is adapted to pick up a storage container from the lower storage system 10. The body of the robot 50 comprises a cavity for receiving the storage container. In this embodiment, the cavity is arranged centrally within the robot 50 and is surrounded by the body of the robot 50. The body of the robot 50 further comprises a lifting device for raising and lowering the storage container. However, the invention is applicable to any type of robot with wheels.
[0017] The robot 50 further comprises wheels 60 which allow movement of the robot 50 along first and second directions x, y on the underlying storage system 10. The wheels 60 are connected to drive means located at or at least partially within the wheels 60 for providing driving force to the robot 50. This configuration will occupy minimal space within the robot 50, thereby freeing up space for other installations within the robot 50.
[0018] The robot 50 further comprises control means configured to control the movement of the robot 50. The control means for each wheel 60 is connected to drive means, which are connected to each wheel 60. The robot 50 further comprises wireless communication for receiving and transmitting signals.
[0019] 3 shows an overview of the master controller according to the invention. The master controller is adapted to control the movement of a robot 50 from a start position to a stop position, the robot 50 moving on a track laid on a frame structure forming a grid, the robot 50 being controlled by a local controller, Controller 3, as illustrated in the figure. 1-2 , Controller 3-4 Controlled by the wheel pair W 1 and W 2 , W 3 and W 4 and the individual drive means Drive 1 , Drive 2 , Drive 3 , Drive 4 Each individual drive means controls the speed and force applied to the connected wheel.
[0020] The method of the present invention for controlling each wheel of the robot 50 and synchronizing the wheel pairs includes several steps implemented by a master controller. The master controller is preferably housed inside the robot 50, but may also be located outside it. However, this requires more wireless communication between the master controller and the individual local control means housed within the robot 50.
[0021] The first step is to receive the start and stop positions for the robot 50.
[0022] The start and stop positions will depend on the route established for the robot 50 prior to picking a box from a storage row 30 and placing it in another storage row 30. The route for a particular robot 50 will be established by a supervisory system that has control of all storage bins and their contents.
[0023] The starting position of the robot 50 will be the position where it is resting. The robot 50 will track this position at all times. This position can be obtained in different ways. One way is to track the x,y position of the robot 50 relative to a track on the top of the framework. This will be the global position of the robot 50. This position can be obtained using a tracking device located external to the robot 50 or by a device integrated within the robot 50. A combination of external and integrated tracking devices will increase the accuracy of the position determination.
[0024] By using the integrated tracking device, the robot 50 will be able to track its position as it moves on a track laid out as a grid on top of the frame structure by detecting the number of traverses it has made in the x and y-directions from a known starting position, i.e. movements like those between cells in a spreadsheet.
[0025] In addition to the starting position, the master controller must also receive stopping location information in order to control the movement of the robot 50.
[0026] If the robot 50 has to move in only one direction along the route to perform a complete operation to pick up a storage container from one storage row and drop it into another storage row, there will be only one start and stop position for the complete operation. However, it is more likely that the robot 50 will move in different x- and y-directions along the route to reach the final destination. This may be the case if the complete route extends along different directions or due to other robots blocking the shortest route from the start position to the stop position. In this case, the first start position will be the position where the robot 50 picks up or drops the storage container. The first stop position will then be the position on the route where the robot 50 has to change direction to follow the route. This stop position will then be the next start position, and so on. If the robot 50 has to change direction three times, there will be three start and stop positions, i.e., the first, second, and third legs of the route.
[0027] After the start and stop positions of the first leg of the robot's 50 route have been established, the next step is to have the master controller record the current speed V of each wheel of the robot 50. 1 , V 2 , V 3 , V 4 and the angular position pos 1 , pos 2 , pos 3 , pos 4 This information is provided by means of speed and angular position sensors on each wheel that measure these parameters.
[0028] The current speed and angular position for each pair of wheels is stored in the local controller Controller 1-2 , Controller 3-4 which are input to the wheel pair W 1 and W 2 , W 3 and W 4 Controls synchronization.
[0029] As the robot 50 moves along the route, its position relative to the frame structure is continuously tracked and provided to the master controller.
[0030] In one embodiment, the position of the robot 50 is a global x,y position provided by an external tracking device that tracks the robot 50 relative to the track.
[0031] In another embodiment of the present invention, the robot 50 further comprises a tracking sensor to detect its absolute position relative to the track it is currently driving on. Combining the absolute position of the robot 50 with the global position will improve the accuracy of the determined position.
[0032] The master controller determines the start and stop positions and the position of each wheel W 1 , W 2 , W 3 , and W 4 Upon receiving the current velocity and angular position of each pair of wheels W and the current position of the robot 50, the master controller 1-2 and W 3-4 For each individual speed drive sequence V seq1-2 , V seq3-4 The ISP will use this information to set
[0033] Each speed drive sequence V seq1-2 , V seq3-4 is established for each pair of wheels based on the velocity and angular position data in relation to the set start and stop positions and the current position of the robot 50.
[0034] These velocity-driven sequences V seq1-2 , V seq3-4 is the local controller 1-2 , Controller 3-4 This in turn transmits the drive to each pair of wheels. 1 , Drive 2 , Drive 3 , Drive4 Control.
[0035] Each drive sequence will define a set of velocity data that defines the acceleration, constant velocity, and deceleration for each pair of wheels during the movement from a start position to a stop position. 1-2 , Controller 3-4 Drive means for each wheel 1 , Drive 2 , Drive 3 , Drive 4 To control the speed drive sequence V seq1-2 , V seq3-4 would be used.
[0036] As the robot 50 moves along its route, the data defining the velocity drive sequence will be continually updated according to the acceleration, constant velocity, and deceleration of the robot 50. This means that the drive sequence defining the speed for the wheel pairs may vary along the route. The update rate of the velocity drive sequence can be set and transmitted at a pre-defined rate, and may vary along the route of the robot 50 as it moves from a start position to a stop position.
[0037] The different steps defined above are repeated until the robot 50 reaches its destination or when the direction should be changed, i.e. the steps will be repeated between the start position and the stop position for the robot 50.
[0038] In one embodiment of the present invention, the local controller controlling the wheel pair will control the drive of the wheels to adjust the speed of the wheels 60 if the current speed of one wheel 50 deviates from the set speed of the wheel pair set by the speed drive sequence. This means that the wheel pair along the same axis normal to the drive direction will be synchronized to the speed set by the speed drive sequence at all times, regardless of possible causes of wheel speed slowdown, e.g. spinning, skidding, obstacles, etc.
[0039] The local controller will therefore keep the wheel pairs synchronized according to the set speed drive sequence, which will provide precise control of the movement of the robot 50 even if the speed of one or several wheels deviates, for some reason, from the speed set by the speed drive sequence.
[0040] Synchronization can be performed at a fast rate to ensure that the wheel pairs are globally synchronized. Typically, the speed and angular position of each wheel is measured 60,000 times per second to ensure that the wheel pairs remain synchronized to the speed set by the speed drive sequence, and corresponding continuous calculations are performed to control the drive of each wheel.
[0041] The method described above provides optimal control of the movement of the robot 50 to move smoothly from a start position to a stop position without deviation from the angle going forward, regardless of any disturbances that may occur with respect to the wheels as they rotate on the track.
[0042] The invention is also defined by a software program product which, when executed by a processor implementing the method described above, the processor being part of or connected to the master controller.
[0043] The present invention is also defined by a controller for controlling the movements of the robot 50 described above when moving from a start position to a stop position. This will act as a master controller for the movements of the robot 50.
[0044] The master controller controls the wheel pair W 1-2 and W 3-4 Local Controller 1-2 , Controller 3-4 Connected to the local controller 1-2 , Controller 3-4 provides speed and angular position data for each wheel 60 to the master controller using speed and angle sensors connected to the local controllers.
[0045] The master controller determines the start and stop positions of the robot 50 and the local controllers 1-2 , Controller 3-4 and the current speed and angular position of each wheel 60 provided by: a) the current speed and angular position of each wheel 60 provided by: b) the current speed and angular position of each wheel 60 provided by: c) the current speed and angular position of each wheel 60 provided by:
[0046] The master controller further determines the speed and angular position of each pair of wheels 60, i.e., W, based on the current speed and angular position of each wheel 60, the current position of the robot 50, and the starting and stopping positions of the robot 50. 1-2 and W 3-4 For the speed drive sequence V seq1-2 , V seq3-4 The device further comprises a calculation means for setting
[0047] The master controller also controls the speed drive sequence V seq1-2 , V seq3-4 Local Controller 1-2 , Controller 3-4 , whereby each pair of wheels 60, i.e. W1-2 and W 3-4 The speed data is therefore controlled by the master controller and is preferably updated every 5 ms.
[0048] The master controller, in one embodiment, is stored inside the robot 50. It then controls the pair of wheels W 1-2 and W 3-4 A local controller that controls the wheels and reads the speed and angular position data from each wheel. 1-2 , Controller 3-4 is connected to.
[0049] The master controller, in one embodiment, may be connected to a device that provides the global position relative to the frame structure. In another embodiment, this information may be provided by an external means that transmits position data of the robot 50 to the master controller. A combination of on-board and external means for providing the global position of the robot 50 is also feasible.
[0050] The accuracy for determining the position of the robot 50 can be improved by providing local position data provided by tracking sensors included within the robot 50 .
[0051] The present invention will provide controlled smooth movement of a moving robot 50. The robot will move uniformly along the track at all times, i.e., will prevent the robot 50 from moving out of the lead angle due to distortion loads, slippage, or friction problems.
Claims
1. A computer-implemented method for controlling movement of a robot on a plurality of tracks laid on a frame structure forming a grid, the method comprising: receiving a current speed of a first wheel in a first pair of wheels of the robot; receiving a current position of the robot relative to at least a portion of the frame structure; setting a drive sequence for the first pair of wheels based on the current velocity of the first wheel and the current position of the robot; A method comprising:
2. The method described in claim 1, wherein the drive sequence defines a set speed for the first pair of wheels. and adjusting a speed of the first wheel such that movement of the first pair of wheels is synchronized if the current speed received for the first wheel deviates from the set speed defined by the drive sequence. The method of claim 2 , further comprising:
4. A method according to any one of claims 1 to 3, wherein receiving the current velocity, receiving the current position, and setting the drive sequence are performed in a master controller, the master controller being within the robot or configured to communicate wirelessly with the robot.
5. The method of claim 3, wherein adjusting the speed is performed in a local controller within the robot configured to control a first pair of wheels of the robot.
6. A method according to any one of claims 1 to 3, further comprising receiving a stopping position of the robot, wherein the drive sequence for the first pair of wheels is further based on the stopping position of the robot.
7. The method described in claim 6, wherein the drive sequence defines an acceleration, a set speed, and a deceleration for moving the robot to the stop position.
8. A method according to any one of claims 1 to 3, further comprising receiving a starting position of the robot, wherein the drive sequence for the first pair of wheels is further based on the starting position of the robot.
9. A method according to any one of claims 1 to 3, further comprising receiving a current speed of a second wheel in the first pair of wheels of the robot, and setting the drive sequence is further based on the current speed of the second wheel.
10. The method of claim 1, further comprising repeating the method to update the drive sequence.
11. A system for controlling the movement of a robot on a plurality of tracks laid on a frame structure forming a grid, the system comprising: receiving a current speed of a first wheel in a first pair of wheels of the robot; receiving a current position of the robot relative to at least a portion of the frame structure; setting a drive sequence for the first pair of wheels based on the current velocity of the first wheel and the current position of the robot; A system configured to:
12. The system of claim 11, wherein the drive sequence defines a set speed for the first pair of wheels. If the current speed received for the first wheel deviates from the set speed defined by the drive sequence, adjusting the speed of the first wheel such that movements of the first pair of wheels are synchronized. The system of claim 12 , further configured to:
14. A system as described in any of claims 11 to 13, wherein the system includes a master controller that is located within the robot or configured to communicate wirelessly with the robot, and wherein receiving the current velocity, receiving the current position, and setting the drive sequence are performed in the master controller.
15. The system described in claim 13, further comprising a local controller within the robot configured to control a first pair of wheels of the robot, and adjusting the speed is performed in the local controller.
16. A system as described in any of claims 11 to 13, wherein the system is further configured to receive a stopping position of the robot, and the drive sequence for the first pair of wheels is further based on the stopping position of the robot.
17. The system described in claim 16, wherein the drive sequence defines acceleration, a set speed, and deceleration for moving the robot to the stop position.
18. The system further configured to receive a starting position of the robot; The system of any of claims 11 to 13, wherein the actuation sequence for the first pair of wheels is further based on the starting position of the robot.
19. A system as described in any of claims 11 to 13, wherein the system is further configured to receive a current speed of a second wheel in the first pair of wheels of the robot, and setting the drive sequence is further based on the current speed of the second wheel.
20. A non-transitory computer readable medium storing a software program product that, when executed by one or more processors of a computing system, causes the computing system to perform a method, the method comprising: receiving a current speed of a first wheel of a first pair of wheels of the robot; receiving a current position of the robot relative to at least a portion of the frame structure; setting a drive sequence for the first pair of wheels based on the current velocity of the first wheel and the current position of the robot; 16. A non-transitory computer readable medium comprising: