Robotic system including a mobile robot

Abstract

A robot system comprises at least one robot (1; 1A, 1B, 1C) that moves actively or passively between at least a first position and a second position (A, B, ..., E), and a first safety configuration is defined at least for the first position (A). A first data carrier (9A) associated with the first safety configuration is located in the first position (A), and the robot (1; 1A, 1B, 1C) comprises a reader (8) that is suitable for reading the first data carrier (9A) when the robot (1; 1A, 1B, 1C) is in the first position (A).

Description

Technical Field

[0001] The invention relates to a robot system in which at least one robot can be used successively in different locations, or in which a given location can be occupied by different robots at different times. Background Art

[0002] The robot conventionally comprises a controller, a base and an end effector which can be moved relative to the base by the controller. The base can be stationary, it can be equipped with casters or the like that facilitate passive movement of the robot from one position to another, or it can include a travel mechanism that facilitates active movement of the robot. In the following description, if nothing else is said, any change in position of the end effector relative to the base will be referred to as movement or displacement of the end effector, and movement of the robot will be referred to as a change in position of the robot as a whole (including its base).

[0003] In order to ensure the safety of the operation of the robot, and in particular to minimize the risk of injury to humans working with the robot, a safety configuration must be defined that imposes limits on operating parameters (such as the robot's speed, position or force) that, while not restricting the freedom of movement of the robot's end effector more than necessary, will ensure that contact between humans and the robot is avoided or at least can occur at harmless speeds or force levels. The safety configuration may also impose limits on the operation of other equipment at the location (e.g., conveyors), and / or may specify the presence of specific perimeter protection equipment. The safety configuration is essentially location-specific, i.e., when the robot moves from one location to another, it will have to implement a new safety configuration associated with the new location.

[0004] Designing a safety configuration requires specialized labor and is therefore costly.

[0005] Quite often, the productivity of a robot is so high that it will not be constantly busy with the work to be done at a particular location, so it may be desirable to move it to a new location from time to time in order to use the robot efficiently. For regulatory reasons, it may be necessary to have skilled employees ensure that the proper safety configuration is implemented when the robot is put into use in a new location, making moving the robot expensive and time consuming.

[0006] While in the past robots tended to move passively and infrequently, the problem has been exacerbated with the advent of active mobile robots that can autonomously select and move to where they are needed. Any productivity gains to be achieved through the robot's ability to figure out where it is needed and move there will be frustrated if no personnel are present at the new location to verify implementation of the proper safety configuration and authorize the robot's operation. Summary of the invention

[0007] It is therefore an object of the present invention to provide a robotic system and an operating method which enable a mobile robot to operate efficiently while respecting any safety-related constraints.

[0008] According to a first aspect of the invention, the object is achieved by a robot system comprising at least one robot that moves actively or passively between at least a first position and a second position, a first safety configuration being defined at least for the first position, characterised in that a first data carrier associated with the first safety configuration is located in the first position, and in that the robot comprises a reader that is suitable for reading the first data carrier when the robot is in the first position.

[0009] Thus, each time the robot moves to a first position, it can access the data carrier via the reader to identify the safety configuration associated with this position, i.e. the first safety configuration. To ensure that the data carrier is read correctly, a rated reader (PLd / Cat3 or higher) can be used; such readers are commercially available; therefore, verification by a dedicated person is obsolete.

[0010] Various types of readers may be used, and the invention is not limited as to the means used to achieve the desired degree of reliability or as to the reading technique.

[0011] Regarding reading technology, the reader can be an optical device such as a camera, laser scanner, etc.

[0012] In that case, the data carrier can be a printed label, such as a QR code sticker. By placing the data carrier in a certain way so as not to be visible from other positions, it can be ensured that the safety configuration it refers to will be implemented when and only when the robot is in the first position.

[0013] Alternatively, the reader may be a radio device adapted to communicate with the data carrier by means of radio waves. By using a short-range radio communication technology (such as NFC, RFID or Blue tooth) it can be ensured that the first data carrier cannot be read from any other position (except the first position), thus ensuring that the mentioned safety configuration of the first data carrier will be implemented when and only when the robot is in the first position.

[0014] The data carrier should be adapted to respond to inquiries from the reader. In that way, the availability of the data is ensured without the data carrier having to broadcast them continuously. In that way, radio pollution is minimized and the radio bandwidth required for reading the data carrier can be kept small. Further, since the energy consumption of the data carrier is thus kept low, wiring the data carrier to a power supply can be avoided. In practice, in particular if an RFID transponder is used as data carrier, the energy required for broadcasting the data stored in the first data carrier can be harvested by the data carrier from the inquiry signal.

[0015] The reader may be located at any suitable position on the robot; it may be fixed relative to the base of the robot, in which case its position at a given location is predictable, and the position of the tag at that location may be chosen so that the tag is easily read from the reader's predicted position.

[0016] Alternatively, it may be advantageous to place the reader near the end effector so as to be movable together with the end effector; in that case, if the reader initially fails to detect the data carrier, the reader can be moved to a position where it can detect the data carrier.

[0017] At the second position, a second safety configuration may be defined, and a second data carrier associated with the second safety configuration may be arranged at the second position and adapted to be read by the reader when the robot is in the second position. In that way, each time the robot moves from the first position to or to the second position or back, it can update its safety configuration. In practice, there is no upper limit to the number of positions and associated safety configurations that the robot may have.

[0018] The first data carrier should be positioned so as not to be readable by said reader when the robot is in said second position, and / or vice versa. In that way, implementation of a safety configuration which is not associated with the position in which the robot is located can be safely prevented.

[0019] In order to safely prevent inappropriate movement of the robot in case a data carrier cannot be correctly read, the robot may store a backup safety configuration and be adapted to use it in case an attempt to read a data carrier fails, for example because there is no direct line of sight between the reader and the data carrier or because the nearest data carrier is outside the detection range of the reader. In the simplest case, the backup configuration may prohibit any operation of the robot, but since this situation cannot be directly distinguished from some technical failure, it is preferred that the backup configuration allows a limited mobility of the end effector. If the reader can be moved together with the end effector as described above, the mobility allowed by the backup configuration should at least be sufficient to move the reader to a position from which the data carrier can be read.

[0020] In a preferred embodiment, the backup configuration imposes no restrictions on the positions the end effector can take relative to the base, but the speed and force with which the end effector moves are set to sufficiently low levels to ensure that a person is not struck or crushed.

[0021] In the case where the robot is actively moving, particularly if it is designed to move autonomously from one location to another, the backup configuration may also be applicable while the robot is moving.

[0022] At least if the robot is moved passively, it will have to stop working while it is moving. Therefore, any interruption in work may indicate that the robot has moved to a new location. In order to ensure that a suitable safety configuration is implemented, the robot should be adapted to attempt to read the data carrier when resuming work after an interruption.

[0023] If the robot is actively moving, it should be adapted to attempt to read the data carrier after having actively moved a predetermined distance. If such a data carrier is found, its associated safety configuration may, for example, allow the robot to move to the target position faster than the backup configuration would, thus minimizing the time spent unproductively on the shift.

[0024] According to a second aspect of the present invention, the object is achieved by a method of operating a robot in a robotic system, the robotic system comprising at least a first position and a second position, and at least one robot that moves actively or passively between the first position and the second position, the method comprising the following steps:

[0025] a) moving the robot to a first position, the first position having a first safety configuration associated therewith;

[0026] b) searching for a first data carrier in said first location using a reader of said robot;

[0027] c) when the first data carrier is found, reading it in order to retrieve the first security configuration; and

[0028] d) When the first safety configuration is retrieved, it is implemented in the robot.

[0029] Unless the first safety configuration has been implemented, the robot should be prohibited from executing the work program.

[0030] Finally, according to a third aspect, the object is achieved by a software product comprising instructions which, when executed by a robot, cause the robot to carry out the method described above.

[0031] Further features and advantages of the present invention will become apparent from the following description of embodiments thereof with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 is a schematic plan view of a location in which a robot may be located in order to perform a specific task;

[0033] Figure 2 is a schematic plan view of a robotic system including a plurality of locations and a plurality of robots that can be moved from one of the locations to another in order to perform assigned tasks; and

[0034] Figure 3 is Figure 2 Flow chart of a method for operating a robot in a system. DETAILED DESCRIPTION

[0035] Figure 1 Schematically illustrated is a position in which a robot 1 is placed for carrying out a predetermined work procedure on a workpiece 2, the workpieces may be held in position in an inventory so that the robot 1 picks up a new workpiece 2 from the inventory after completing work on a previous workpiece, or the workpieces may be brought into the reach of the robot by a conveyor or the like.

[0036] The robot 1 has: an articulated arm of conventional design, which includes a base 3, an end effector 5 and a plurality of links 4 connected to each other, the base 3 and the end effector 5 by revolute joints or prismatic joints; and a controller 6 for controlling the movement of the arm, that is, the movement of the end effector 5 relative to the base 3. Incidentally, the arm and the controller 6 are mounted on a travel mechanism such as a carriage 7 having a plurality of motorized casters or tracks (not shown), and the controller 6 is adapted to control the orientation and speed of the casters or to control the speed of the tracks so that the robot 1 can be moved to another position when necessary.

[0037] An optical reader 8 (e.g., a barcode or QR code scanner) is mounted on bracket 7. Such readers are widely used in POS equipment and are known to be able to recognize and read codes at a wide range of angles and with high reliability. A label 9 (with a code printed thereon that is compatible with reader 8) is attached to the surface at a selected location so as to be visible from the perspective of reader 8.

[0038] In principle, for Figure 1The complete safety configuration for the location shown in can be encoded in the tag 9. Preferably, encoded in the tag 9 is a reference (e.g., an address or link) to a centralized storage device 10 where the safety configuration can be accessed and downloaded to the controller 6, or a site ID that is unique to the location where the robot is currently placed and can be read by the reader 8 and used by the controller 6 to query the safety configuration associated with that location from the centralized storage device 10. Thus, the safety configuration can be updated at any time without having to replace the tag 9.

[0039] The safety configuration may impose various types of restrictions on the mobility of the arm. It may define an area 11 that the end effector 5 is not allowed to leave when working at a location, it may impose acceleration limits on the parts of the robot 1 outside of the area 11, it may define an area 12 surrounding a wall or other fixed object of the location that may not be entered by any part of the robot in order to prevent people from being squeezed between the robot and the fixed object. The safety configuration may further identify perimeter guards 13 that are required to handshake with the controller 6 in order to prove that they are present and effective, so that if the perimeter guards 13 detect that someone has intruded into the area reserved for the robot 1, for example, an emergency shutdown of the robot 1 may be triggered.

[0040] In an alternative embodiment, the reader 8 is mounted on the distal link 4 of the arm together with the end effector 5. That way, if the reader 8 fails to read the tag 9 (e.g., due to an intervening obstacle blocking the line of sight), the robot can carefully move the reader by referring to the alternate configuration and try to find a position from which it can read the tag 9. In this embodiment, it may be advantageous to facilitate finding the tag by attaching clear tags 9 at various locations in the location.

[0041] In a further alternative embodiment, the tag 9 is an RFID tag and the reader 8 is an RFID reader. The RFID reader can read the RFID tag even if the line of sight between the two is blocked. The RFID tag can be designed to harvest the energy it needs to transmit its data to the reader 8 from the query signal transmitted by the reader 8.

[0042] It is also possible to combine visual and radio detection, for example by using a tag 9 that is both visually unique and capable of radio communication, so that in a first step the camera of the robot 1 can be used to detect the tag 9 and control the movement of the RFID reader so that its detection range overlaps with the tag 9.

[0043] Figure 2is a schematic plan view of a robot system comprising a plurality of positions AD at which robots 1A-1C of the type described above can perform specific tasks. For simplicity, it will be assumed that each of the robots 1A-1C is suitable for each task. Since there are fewer robots than positions for performing tasks, workpieces will accumulate at unoccupied positions (e.g., position B). Therefore, at a certain moment, when the supply of workpieces at position A has been exhausted, the robot 1A has moved from position A to position B and has been connected to the mains voltage source 14 there (see FIG. 1 ). Figure 1 ).

[0044] Upon detection ( Figure 3 , step S1) when the mains voltage has been reconnected, the controller 6 of the robot 1A determines that a position change may have occurred and that the previously stored safety configuration is likely to be invalid. (In an alternative embodiment, the controller 6 may be programmed to periodically poll for the presence of a tag 9 within the detection range of the reader 8, and if no tag 9 is found within the detection range or if a tag 9 is found but its identity is different from the identity of the tag detected in the previous polling, the previously stored safety configuration is invalidated. Therefore, it switches (S2) to an alternate configuration, if any, which allows the end effector 5 to move only at a very low speed or with very little force. It then instructs the reader 8 to read a reference to the valid safety configuration from the tag 9 (S3). If the read is successful (S4), the controller 6 retrieves (S5) the safety configuration identified by the reference from the storage device 10 and implements the safety configuration (S6). The controller 6 further downloads (S1) a program defining the movements to be implemented by the end effector 5 in order to complete the work at position B, and starts the work (S8).

[0045] Assuming that the workpiece at position B is prepared at position A, position B will sooner or later run out of supply while position A is empty. Therefore, at some later time, the workpiece currently busy Figure 3 The robot 1C of step S8 of the method will stop working (S9) and leave position D in order to occupy position A. When it is found (S10) that the carriage 7 of the robot 1B has moved more than a predetermined distance (thus leaving the allowed working range of position D), the safety configuration of position D becomes invalid and the robot 1B uses the reader 9 to find a reference to the new safety configuration (S11).

[0046] If the attempt fails, the method returns to step S2, i.e. the robot 1B is forced to implement the alternative configuration and thus moves slowly. If the entire path to position A has to be traversed at such a low speed, the movement to position A may go terribly wrong. To avoid this, a robot highway E ( Figure 2), humans are not allowed to enter this robot highway, and therefore the robot can move quickly on this highway. At each entry point 15 to the highway E, there is a tag 9E to be read by the robot 1B, which the robot looks for in step S3. The safety configuration referenced by the tag 9E can be valid for the entire highway E, preferably it is only valid for a specific section of the highway E following the tag 9E. The implementation of this safety configuration (S4-S6) enables the robot 1B to circulate on the highway E at the maximum speed defined in the safety configuration. Therefore, the highway E is manipulated like one of the positions AD, with the only exception that there is no work program to be implemented, i.e., steps S7 and S8 are invalid when implemented by the robot 1C passing through one of the highway entry points 15.

[0047] The tags 9E' are placed along the highway E so that they are visible to the robot after a predetermined distance has passed, i.e., so that when the robot 1C moving along the highway calls step S11, there is a tag 9E' to be found and the reading step S12 can be successfully implemented. In that way, the robot 1C can continue to run at high speed while on the highway E. If the robot 1C fails to find a new tag 9E', it will return to the backup configuration (S2). In this way, it can be ensured that even if the robot 1B leaves the highway E by accident, it will stop traveling at high speed and will not cause a safety threat (even if it has left the highway E by accident).

[0048] Furthermore, tags 9E' distributed along the highway allow different safety configurations to be imposed on different sections of the highway E, such as speed limits at turns or intersections.

[0049] When robot 1C has successfully reached position A, the tag it will see in step S11 is tag 9A of position A, causing it to return to step S5 and thereby download and implement (S6) the safety configuration of position A, download the work program of position A (S1) and execute the work program (S8).

[0050] Reference numerals

[0051] 1. 1A, 1B, 1C Robots

[0052] 2 Workpiece

[0053] 3 Base

[0054] 4 Connecting rod

[0055] 5 End Effector

[0056] 6 Controller

[0057] 7 Bracket

[0058] 8 Reader

[0059] 9, 9A, 9E, 9E labels

[0060] 10 Storage Devices

[0061] 11 Region

[0062] 12 Regions

[0063] 13 Peripheral protection devices

[0064] 14 Mains voltage source

[0065] 15 Highway access points

Claims

1. A robot system comprising at least one robot (1; 1A, 1B, 1C) that moves actively or passively between at least a first position and a second position (A, B, ..., E), wherein a first safety configuration is defined at least for the first position (A), characterized in that A first data carrier (9A) associated with the first safety configuration is located in the first position (A), and the robot (1; 1A, 1B, 1C) comprises a reader (8) suitable for reading the first data carrier (9A) when the robot (1; 1A, 1B, 1C) is in the first position (A), and the robot is also configured to: invalidate the first safety configuration in response to moving a predetermined distance and leaving the working range of the first position, recognizing that at least one of the robots has been reconnected to the mains voltage source, and attempt to read a second data carrier to retrieve a second safety configuration of the second position.

2. A robot system according to claim 1, wherein the data carrier (9A) stores one of the first safety configurations and a reference to a storage device (10), which is accessible to the robot (1; 1A, 1B, 1C) and stores the first safety configuration.

3. The robotic system according to claim 1 or 2, wherein the reader (8) is an optical device.

4. The robotic system according to claim 1 or 2, wherein the reader (8) is a radio device.

5. The robotic system according to claim 4, wherein the data carrier (9) is adapted to respond to queries from the reader.

6. A robot system according to any one of the preceding claims 1 to 2, 5, wherein the robot (1) comprises a base (3) and an end effector (5) capable of moving relative to the base (3), and wherein the reader (8) is fixed relative to the base.

7. A robot system according to any one of claims 1 to 2 and 5, wherein the robot (1) comprises a base (3) and an end effector (5) capable of moving relative to the base (3), and wherein the reader (8) is installed adjacent to the end effector (5) so as to also be capable of moving relative to the base (3).

8. A robot system according to any one of the preceding claims 1 to 2 and 5, wherein the second safety configuration is defined for the second position (B, C, D, E), and the second data carrier (9B, 9C, 9D, 9E, 9E') associated with the second safety configuration is arranged at the second position (B, C, D, E) and is suitable for being read by the reader (8) when the robot is in the second position (B, C, D, E).

9. A robot system according to claim 8, wherein said first data carrier (9A) is positioned so as not to be readable by said reader (8) when said robot (1; 1A, 1B, 1C) is in said second position (B, C, D, E).

10. A robot system according to any one of the preceding claims 1 to 2, 5, wherein the robot (1; 1A, 1B, 1C) stores a backup safety configuration and is adapted (S2) to use the backup safety configuration when an attempt to read (S4, S12) a data carrier (9; 9A, 9B, 9C, 9D, 9E, 9E') fails.

11. A robot system according to any one of the preceding claims 1 to 2, 5, wherein the robot (1; 1A, 1B, 1C) is adapted to attempt to read (S1) a data carrier (9; 9A, 9B, 9C, 9D, 9E, 9E') when resuming work after an interruption.

12. A method for operating a robot (1; 1A, 1B, 1C) in a robot system, the robot system comprising at least a first position (A) and a second position (B, C, D, E), and at least one robot (1; 1A, 1B, 1C) moving actively or passively between the first position and the second position (A, B, ..., E), the method comprising the following steps: a) moving the robot (1; 1A, 1B, 1C) to a first position, the first position having a first safety configuration associated therewith; b) searching (S3, S11) for a first data carrier (9A) in said first location (A) using a reader of said robot; c) when said first data carrier (9A) is found, reading (S4, S12) it in order to retrieve (S5) said first security configuration; as well as d) when said first safety configuration is retrieved, implementing (S6) it in said robot (1; 1A, 1B, 1C); and e) in response to the robot moving a predetermined distance, out of the working range of the first position and recognizing that the robot has been reconnected to a mains voltage source, invalidating the first safety configuration and attempting to read a second data carrier to retrieve a second safety configuration for the second position.

13. The method according to claim 12, wherein the robot (1; 1A, 1B, 1C) is inhibited from executing a work program unless the first safety configuration has been implemented.

14. A software product comprising instructions which, when executed by a robot (1; 1A, 1B, 1C), cause the robot (1; 1A, 1B, 1C) to implement the method according to claim 12 or 13.

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