Robot control method and robot system

Abstract

To provide a robot control method for allowing a robot to perform a work on an object without correcting meandering of a belt.SOLUTION: A control method for a robot 15 performs a work on workpiece 11 conveyed by a belt conveyor 3 for moving a belt 6 allows a first imaging device 13 to detect inclinations in a first direction 9 to be a reference that the belt 6 travels and a direction where the belt 6 travels, and a first distance 22 that is a distance between the belt 6 in a second direction 18 perpendicular to the first direction 9 at a first reference position 19a, and the first reference position 19a, calculates a position of the workpiece 11 when the workpiece 11 is moved from the first position 11a to a second position 11b apart by a second distance 26 relative to the first direction 9 by the belt conveyor 3 on the basis of the inclinations and the first distance 22 detected by the first imaging device 13, and allows the robot 15 to perform a work on the workpiece 11 at the calculated second position 11b.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a robot control method and a robot system. [Background technology]

[0002] Conventionally, a robot system is known in which a robot picks up an object transported by a belt conveyor. If the belt of the belt conveyor meanders, the robot may fail to pick up the object. Patent Document 1 discloses a belt conveyor equipped with a correction mechanism for correcting the meandering of the belt. According to this, a detection roller detects the edge of the belt and outputs a detection signal to a carrier actuator. The carrier actuator corrects the meandering of the belt by adjusting the traveling direction of the belt. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 62-100306 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in order to carry out the method of Patent Document 1, it is necessary to provide the belt conveyor with a mechanism for correcting meandering of the belt. Since various structures are attached to the robot and the belt conveyor, it may not be possible to install a mechanism for correcting meandering. Therefore, there has been a demand for a robot control method that allows the robot to perform work on an object without correcting the meandering of the belt. [Means for solving the problem]

[0005] A method for controlling a robot is a method for controlling a robot that performs work on an object transported by a conveyor along a moving belt, in which a detection unit detects an inclination between a first direction that is the reference for the belt's travel and the direction in which the belt is traveling, and a first distance that is the distance between the belt and the detection reference position in a second direction perpendicular to the first direction at a detection reference position, and based on the inclination and first distance detected by the detection unit, a position of the object when the object moves by the conveyor from a first position to a second position a second distance away in the first direction is calculated, and the robot performs work on the object at the calculated second position.

[0006] The robot system includes a conveyor along which a belt carrying an object moves to transport the object, a detection unit that detects an inclination between a first direction that is the reference direction for the belt to travel and the direction in which the belt is traveling, and a first distance that is the distance between the belt and the detection reference position in a second direction perpendicular to the first direction at a detection reference position, and a calculation unit that calculates a position of the object when the object moves from a first position to a second position a second distance away in the first direction by the conveyor based on the inclination and the first distance detected by the detection unit, and a robot that performs work on the object at the second position calculated by the calculation unit. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a schematic side view showing a configuration of a robot system according to a first embodiment. [Diagram 2] FIG. 2 is a schematic plan view showing the configuration of a belt conveyor. [Diagram 3] FIG. 2 is a schematic plan view showing the configuration of a belt conveyor. [Figure 4] Electrical block diagram of the robot system. [Diagram 5] 1 is a flowchart of a method for controlling a robot. [Figure 6] 1 is a flowchart of a method for controlling a robot. [Figure 7]10 is a flowchart of a robot control method according to a second embodiment. [Figure 8] 13 is a flowchart of a robot control method according to a third embodiment. [Figure 9] FIG. 13 is a schematic plan view showing the configuration of a belt conveyor according to a fourth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] First embodiment In this embodiment, a characteristic example of a robot system equipped with a belt conveyor and a method for controlling a robot in this robot system will be described.

[0009] As shown in Fig. 1, the robot system 1 is provided with a belt conveyor 3 as a conveyor on a base 2. The belt conveyor 3 is provided with a first pulley 4 and a second pulley 5. A belt 6 is hung between the first pulley 4 and the second pulley 5. The belt conveyor 3 is provided with a first motor 7. The torque of the first motor 7 is transmitted to the first pulley 4 by a transmission mechanism including a timing belt 8 and the like. When the shaft of the first motor 7 rotates, the first pulley 4 rotates and the belt 6 moves.

[0010] The direction from the first pulley 4 to the second pulley 5 is the X positive direction. The width direction of the belt conveyor 3 is the Y direction. The direction from the base 2 to the belt conveyor 3 is the Z positive direction. The X direction, Y direction, and Z direction are perpendicular to each other.

[0011] When the belt conveyor 3 is installed on the base 2, the belt 6 is adjusted so that it does not meander. The direction in which the belt 6 moves at this time is the first direction 9. In other words, the first direction 9 can be said to be the reference direction in which the belt 6 moves. With respect to the belt 6, the first pulley 4 side is the upstream side, and the second pulley 5 side is the downstream side. The first direction 9 is the positive X direction. A workpiece 11 is placed on the belt 6 as an object. The workpiece 11 is transported by the belt conveyor 3 along which the belt 6 moves. The direction of travel of the belt 6 may meander due to aging. When the belt 6 meanders, the direction of travel of the belt 6 deviates from the first direction 9.

[0012] A first rotary encoder 12 is installed on the first pulley 4 as a detection unit. The first rotary encoder 12 detects the rotation angle of the first pulley 4. The rotation angle of the first pulley 4 and the amount of movement of the belt 6 are directly proportional to each other. Therefore, the amount of movement of the workpiece 11 in the first direction 9 is detected from the output of the first rotary encoder 12.

[0013] A first imaging device 13 serving as a detector and an imaging device is disposed downstream of the first pulley 4 in the positive Z direction of the belt 6. A second imaging device 14 serving as a detector and an imaging device is disposed upstream of the second pulley 5 in the positive Z direction of the belt 6. The first imaging device 13 photographs the upstream side of the belt 6, and the second imaging device 14 photographs the downstream side of the belt 6.

[0014] The workpiece 11 is placed upstream of the imaging range of the first imaging device 13. Therefore, after the workpiece 11 is placed on the belt 6, the workpiece 11 is imaged by the first imaging device 13.

[0015] A robot 15 is installed between the first imaging device 13 and the second imaging device 14. The robot 15 includes a robot body 15a and a control device 15b. The robot body 15a is installed on an installation stand 16 installed on the base 2. The robot body 15a includes a plurality of arms 15c that are connected to each other. The arms 15c include actuators 17 at their tips.

[0016] The robot body 15a includes a plurality of second motors 15d and a second encoder 15e for rotating the arms 15c. The control device 15b drives the second motors 15d and the second encoders 15e to control the position of the actuator 17.

[0017] The arm 15c has an elevator 15f at its tip. The elevator 15f raises and lowers the actuator 17. The control device 15b drives the elevator 15f to control the position of the actuator 17 in the Z direction.

[0018] The actuator 17 is, for example, a hand that grips the workpiece 11, a motor driver, etc. The control device 15b controls the driving of the actuator 17.

[0019] The robot 15 is omitted in Fig. 2. As shown in Fig. 2, a direction perpendicular to the first direction 9 in the XY plane is defined as a second direction 18. The second direction 18 is the negative Y direction. Fig. 2 shows a first imaging range 19 which is the range imaged by the first imaging device 13. Furthermore, a second imaging range 21 which is the range imaged by the second imaging device 14 is shown. The first imaging range 19 and the second imaging range 21 are rectangular.

[0020] On the side of first shooting range 19 on the Y positive direction side, the midpoint of first shooting range 19 in first direction 9 is set to first reference position 19a as a detection reference position. On the side of second shooting range 21 on the Y positive direction side, the midpoint of second shooting range 21 in first direction 9 is set to second reference position 21a as a detection reference position. First reference position 19a and second reference position 21a are located on both ends of belt 6 in first direction 9.

[0021] The belt 6 has a center line 6a that is a line along the direction in which the belt 6 travels. The center line 6a is disposed at the center of the belt 6 in the Y direction. When the belt 6 is not meandering, the center line 6a is a line that is along the first direction 9.

[0022] The distance between the first reference position 19a and the center line 6a in the second direction 18 is defined as a first distance 22. The first distance 22 is the distance between the first reference position 19a and the center line 6a in the second direction 18. A line along the direction in which The first imaging device 13 detects a first distance 22, which corresponds to the distance between the first reference position 19a and the first imaging device 13.

[0023] The distance between the second reference position 21a and the center line 6a in the second direction 18 is defined as a third distance 23. The third distance 23 is the distance between the second reference position 21a and the center line 6a in the second direction 18. A line along the direction in which The second imaging device 14 detects a third distance 23, which corresponds to the distance between the first reference position 21a and the second reference position 21a.

[0024] According to this configuration, the detection unit of the robot system 1 includes the first imaging device 13 and the second imaging device 14. The position of the belt 6 in the second direction 18 can be detected from the position of the center line 6a of the belt 6 in the images captured by the first imaging device 13 and the second imaging device 14.

[0025] A line connecting the first reference position 19a and the second reference position 21a is defined as a virtual line 24. The virtual line 24 passes through the first reference position 19a and extends in the first direction 9. The distance between the first reference position 19a and the second reference position 21a in the first direction 9 is defined as an inter-reference distance 25. The inter-reference distance 25 is a known value that is set based on the positions of the first imaging device 13 and the second imaging device 14.

[0026] The distance between the first reference position 19a and the workpiece 11 in the first direction 9 is defined as a second distance 26. In the first direction 9, the first imaging device 13 detects the workpiece 11 at the timing when the workpiece 11 passes a position overlapping with the first reference position 19a. The first rotary encoder 12 detects the distance the belt 6 moves the workpiece 11 from the position where the first imaging device 13 detects the workpiece 11. The second distance 26 is detected by the first rotary encoder 12 and the first imaging device 13.

[0027] FIG. 3 shows the belt 6 meandering. The center line 6a is inclined with respect to the imaginary line 24. The first distance 22 is Y1. The third distance 23 is Y2. The reference distance 25 is L. The inclination of the belt 6 with respect to the imaginary line 24 is expressed as (Y1-Y2) / L. In this way, the belt 6 in the second direction 18 with respect to the imaginary line 24 A line along the direction in which By detecting the position, the inclination between the first direction 9 and the direction in which the belt 6 moves is detected.

[0028] According to this configuration, the belt 6 is A line along the direction in which The position of the belt 6 is detected by the first imaging device 13 and the second imaging device 14. Therefore, the inclination of the belt 6 with respect to the traveling direction can be detected with high accuracy.

[0029] The second distance 26 is designated as Xcnv. The distance that the workpiece 11 moves in the second direction 18 due to the inclination of the belt 6 is expressed as (Y1-Y2) x Xcnv / L. In this manner, when the belt 6 meanders and is inclined, the distance that the workpiece 11 moves in the second direction 18 can be detected.

[0030] 4, the control device 15b includes a CPU 27 (Central Processing Unit) that performs various calculation processes, and a memory 28 that stores various information. A robot driving device 29, the first imaging device 13, the second imaging device 14, the belt conveyor 3, the input device 31, and the output device 32 are connected to the CPU 27 via an input / output interface 33 and a data bus 34.

[0031] The robot driving device 29 is a device that drives the robot body 15a. The robot driving device 29 drives the second motor 15d, the second encoder 15e, the lifting device 15f, and the actuator 17 of the robot body 15a.

[0032] Data of the images captured by the first imaging device 13 and the second imaging device 14 is transmitted to the CPU 27 via the input / output interface 33 and the data bus 34 .

[0033] The output of the first rotary encoder 12 of the belt conveyor 3 is transmitted to the CPU 27 via an input / output interface 33 and a data bus 34 .

[0034] The input device 31 is a keyboard, a joystick, etc. An operator operates the input device 31 to input various instructions.

[0035] The output device 32 is a display device, an external output device, etc. The operator checks various information by looking at the display device. The output device 32 has an external interface for communicating with an external device.

[0036] The memory 28 is composed of semiconductor memories such as RAM (Random Access Memory) and ROM (Read Only Memory). The memory 28 stores a program 35 in which the operation procedure of the robot main body 15a is described. In addition, the memory 28 stores belt measurement data 36. The belt measurement data 36 is data indicating meandering and positional deviation of the belt 6. In addition, the memory 28 stores work position data 37. The work position data 37 is data indicating the position of the work 11 on the belt 6. In addition, the memory 28 stores image data 38. The image data 38 is data of images captured by the first imaging device 13 and the second imaging device 14. In addition, the memory 28 has a memory area that functions as a work area for the operation of the CPU 27, a temporary file, etc., and various other memory areas.

[0037] The CPU 27 drives the robot system 1 in accordance with a program 35 stored in the memory 28. The CPU 27 on which the program 35 runs has a robot control unit 41 as a specific function realization unit. The robot control unit 41 controls the operation of the robot main body 15a.

[0038] Additionally, the CPU 27 has an imaging control unit 42 as a detection unit. The imaging control unit 42 controls the timing of imaging by the first imaging device 13 and the second imaging device 14. The imaging control unit 42 detects the first distance 22 from the image captured by the first imaging device 13. The imaging control unit 42 detects the third distance 23 from the image captured by the second imaging device 14.

[0039] According to this configuration, the belt 6 has a center line 6a along the traveling direction. The first imaging device 13 captures an image of the center line 6a. The imaging control unit 42 can detect the position of the belt 6 in the second direction 18 from the position of the center line 6a in the captured image.

[0040] Additionally, the CPU 27 has a position correction calculation unit 43 as a detection unit and a calculation unit. The position correction calculation unit 43 detects the inclination between the first direction 9 and the direction in which the belt 6 travels.

[0041] The position correction calculation unit 43 calculates the position of the workpiece 11 based on the inclination between the detected first direction 9 and the direction in which the belt 6 travels, and the first distance 22. In other words, the position correction calculation unit 43 calculates the amount of correction when the position of the workpiece 11 fluctuates due to meandering and positional deviation of the belt 6.

[0042] Additionally, the CPU 27 has a work position calculation unit 44. The work position calculation unit 44 calculates the position of the work 11 when the belt 6 is not meandering.

[0043] Additionally, the CPU 27 has a belt control unit 45. The belt control unit 45 controls the moving speed of the belt 6. The belt control unit 45 receives the output of the first rotary encoder 12 and recognizes the moving speed and amount of movement of the belt 6.

[0044] Next, a control procedure of the robot system 1, including a control method for the robot 15, will be described. Fig. 5 shows the preparation work carried out before the robot system 1 is put into operation. In Fig. 5, calibration is carried out in step S1. The positional relationship of the coordinate system for controlling the robot main body 15a with respect to the first shooting range 19, the second shooting range 21, and the first direction 9 is measured and stored in the memory 28. Next, the process proceeds to step S2.

[0045] The belt 6 is adjusted to a state where it is not meandering. In step S2, the first distance 22, the third distance 23, and the reference distance 25 are measured when the belt 6 is not meandering. The first imaging device 13 and the second imaging device 14 capture images of the center line 6a. The imaging control unit 42 measures the first distance 22 and the third distance 23 from the captured images. The first distance 22 in the calibration process is Y1cal. The third distance 23 is Y2cal. The reference distance 25 is L. The imaging control unit 42 stores the values ​​of Y1cal, Y2cal, and L in the memory 28 as one of the belt measurement data 36. Since the value of L is a constant, the value is updated only when it changes.

[0046] Fig. 6 shows a procedure in which the robot 15 picks up the workpiece 11 being transported on the belt 6. In Fig. 6, the first imaging device 13 photographs the workpiece 11 in step S3. In Fig. 2, when the workpiece 11 is transported to the first imaging range 19, the first imaging device 13 photographs the workpiece 11. The position of the workpiece 11 at this time is referred to as a first position 11a.

[0047] The imaging control unit 42 detects the first position 11a and the first distance 22. The first distance 22 is set as Y1img. The imaging control unit 42 stores Y1img in the memory 28 as one piece of the belt measurement data 36. Next, the process proceeds to step S4.

[0048] In step S4, the position correction calculation unit 43 calculates the amount of deviation of the belt 6 after calibration from Y1img. The amount of deviation of the belt 6 after calibration is indicated by Y1cal-Y1img. Next, the process proceeds to steps S5, S7, and S8.

[0049] Steps S5, S7, and S8 are performed in parallel. In step S7, the workpiece 11 moves on the belt 6 of the belt conveyor 3. In FIG. 2, the position to which the workpiece 11 moves on the belt 6 of the belt conveyor 3 is the second position 11b. The first position 11a and the second position 11b are separated by a second distance 26. Next, the process proceeds to step S9. In step S8, the robot 15 moves the actuator 17 toward the workpiece 11. Next, the process proceeds to step S9.

[0050] In step S5, the first imaging device 13 and the second imaging device 14 capture images of the center line 6a. The first distance 22 is Y1pic. The third distance 23 is Y2pic. The position correction calculation unit 43 calculates the amount of tilt of the meandering of the belt 6 after calibration from Y1pic and Y2pic. The amount of tilt indicating the change in the tilt of the belt 6 after calibration due to meandering is expressed as ((Y1cal-Y1pic)-(Y2cal-Y2pic)) / L. Next, proceed to step S6.

[0051] In step S6, the work position calculation unit 44 calculates the second position 11b when the belt 6 is not meandering. Furthermore, the position correction calculation unit 43 corrects the pickup position based on the deviation amount of the belt 6 calculated in step S4 and the tilt amount calculated in step S5. The correction amount is expressed as ((Y1cal-Y1pic)-(Y2cal-Y2pic))×Xcnv / L+(Y1cal-Y1img).

[0052] In this way, based on the inclination detected by the first imaging device 13, the second imaging device 14, etc. and the first distance 22, the position correction calculation unit 43 calculates the position of the workpiece 11 when the workpiece 11 moves from the first position 11a to the second position 11b, which is the second distance 26 away in the first direction 9, by the belt 6 of the belt conveyor 3. Next, the process proceeds to step S8.

[0053] In step S8, the robot 15 moves the actuator 17 toward the workpiece 11 to the location of the second position 11b corrected by the position correction calculation unit 43. After the workpiece 11 passes through the first shooting range 19, the robot 15 moves the actuator 17 toward the pre-correction second position 11b calculated by the workpiece position calculation unit 44 until the calculation result of the corrected second position 11b is output from the position correction calculation unit 43. Next, the process proceeds to step S9.

[0054] In step S9, the robot control unit 41 receives the signal output by the second encoder 15e and calculates the position of the actuator 17. The robot control unit 41 then determines whether the actuator 17 has reached the upper side of the workpiece 11. If the actuator 17 has not reached the upper side of the workpiece 11, the process proceeds to step S5, step S7, and step S8. If the actuator 17 has reached the upper side of the workpiece 11, the process proceeds to step S10. Here, the upper side of the workpiece 11 refers to the Z positive direction side of the workpiece 11.

[0055] In step S10, the robot 15 performs an operation on the workpiece 11 at the calculated second position 11b. That is, the actuator 17 picks up the workpiece 11. Through the above steps, the procedure for the robot 15 to pick up the workpiece 11 is completed.

[0056] According to the configuration of the robot system 1 and the control method of the robot 15, the inclination between the first direction 9, which is the reference for the movement of the belt 6, and the direction in which the belt 6 is moving, and the distance that the belt 6 moves in the second direction 18 are detected. The workpiece 11 is moved by the belt 6 of the belt conveyor 3. The position of the workpiece 11 at the place where the robot 15 works on the workpiece 11 is calculated from the inclination of the belt 6 and the moving distance in the second direction 18. Therefore, even when the belt 6 meanders, the robot 15 can move the actuator 17 to work on the workpiece 11 at the meandering position. As a result, even when the belt 6 meanders, the robot 15 can work on the workpiece 11 without the need to correct the belt 6.

[0057] Second embodiment This embodiment differs from the first embodiment in that step S5 is performed before steps S7 and S8.

[0058] 7, steps S3 and S4 are the same as those in the first embodiment. The deviation amount of the belt 6 after the calibration is indicated by Y1cal-Y1img. Next, the process proceeds to step S5.

[0059] The content of step S5 is the same as that of the first embodiment. The amount of inclination of the belt 6 after calibration due to meandering is represented by ((Y1cal-Y1pic)-(Y2cal-Y2pic)) / L. Next, the process proceeds to steps S6, S7, and S8. Steps S6, S7, and S8 are performed in parallel.

[0060] In step S6, the work position calculation unit 44 calculates the second position 11b when the belt 6 is not meandering. Furthermore, the position correction calculation unit 43 corrects the pickup position based on the deviation amount of the belt 6 calculated in step S4 and the tilt amount calculated in step S5. The correction amount is expressed as ((Y1cal-Y1pic)-(Y2cal-Y2pic))×Xcnv / L+(Y1cal-Y1img). Since the tilt amount of the belt 6 is not calculated in step S6, the load on the CPU 27 can be reduced.

[0061] The other steps are the same as those in the first embodiment, and therefore the description will be omitted. This method also allows the robot 15 to perform work on the object without the need for correction when the belt 6 meanders.

[0062] Third embodiment This embodiment differs from the first embodiment in that a step corresponding to step S4 is performed in parallel with steps S7 and S8.

[0063] 8, step S3 is the same as in the first embodiment. Next, the process proceeds to step S14, step S7, and step S8. Steps S7 and S8 are the same as in the first embodiment, and therefore the description thereof will be omitted.

[0064] In step S14, the first imaging device 13 and the second imaging device 14 capture images of the center line 6a. The first distance 22 is set to Y1pic. The third distance 23 is set to Y2pic. The position correction calculation unit 43 calculates the amount of deviation of the belt 6 after calibration from Y1pic. The amount of deviation of the belt 6 after calibration is indicated by Y1cal-Y1pic. Next, the process proceeds to step S15.

[0065] In step S15, the position correction calculation unit 43 calculates the amount of inclination of the belt 6 after calibration due to meandering from Y1pic and Y2pic. The amount of inclination of the belt 6 after calibration due to meandering is represented by ((Y1cal-Y1pic)-(Y2cal-Y2pic)) / L. Next, the process proceeds to step S6.

[0066] In step S6, the work position calculation unit 44 calculates the second position 11b when the belt 6 is not meandering. Furthermore, the position correction calculation unit 43 corrects the pickup position based on the amount of deviation of the belt 6 calculated in step S14 and the amount of inclination calculated in step S15. The amount of correction is expressed as ((Y1cal-Y1pic)-(Y2cal-Y2pic))×Xcnv / L+(Y1cal-Y1pic). Next, the process proceeds to step S8.

[0067] The subsequent steps S8, S9, and S10 are the same as those in the first embodiment, and therefore the description thereof will be omitted. Even with this method, the robot 15 can perform work on the target object without the need to correct the belt 6 when the belt 6 meanders. The first distance 22 and the third distance 23 are measured in parallel with the transportation of the workpiece 11. Since the deviation amount and the tilt amount of the belt 6 are calculated, the correction amount can be detected with high accuracy.

[0068] Fourth embodiment The present embodiment differs from the first embodiment in that in the robot system 51, the device that detects the amount of deviation and tilt of the belt 6 is not the first imaging device 13 and the second imaging device 14, but a length measuring device detects the amount of deviation and tilt of the belt 6. Although the robot system 51 includes the first imaging device 13, the first imaging device 13 is disposed to detect the position of the workpiece 11.

[0069] 9, the robot system 51 includes a first length measuring device 52 as a detection unit and a length measuring device, and a second length measuring device 53 as a detection unit and a length measuring device. The surface of the first length measuring device 52 facing the belt 6 is a first detection reference position 52a as a detection reference position. The surface of the second length measuring device 53 facing the belt 6 is a second detection reference position 53a as a detection reference position.

[0070] The end face of the belt 6 on the second direction 18 side is defined as the measurement surface 6b. The first length measuring device 52 detects the distance between the first detection reference position 52a and the measurement surface 6b, and defines this as a first distance 54. The second length measuring device 53 detects the distance between the second detection reference position 53a and the measurement surface 6b, and defines this as a third distance 55.

[0071] According to this configuration, the robot system 51 includes a first length measuring device 52 and a second length measuring device 53 as a detection unit. The length measuring device 52 detects the distance between the measurement surface 6b at the end of the belt 6 and the first detection reference position 52a and the second detection reference position 53a, thereby detecting the length of the belt 6 in the second direction 18. A line along the direction in which The position and inclination of the object can be detected.

[0072] In step S2, the first distance 54 is set to Y1cal. The third distance 55 is set to Y2cal. In step S4, the first distance 54 is set to Y1img. In step S5, the first distance 54 is set to Y1pic. The third distance 55 is set to Y2pic.

[0073] Even in this configuration, the first length measuring device 52 and the second length measuring device 53 detect the amount of deviation and inclination caused by the meandering of the belt 6. As a result, even if the belt 6 meanders, the robot 15 can perform work on the target object without needing to correct the belt 6.

[0074] Fifth embodiment In the first embodiment, the inclination of the belt 6 is detected using the first imaging device 13 and the second imaging device 14. The inclination of the belt 6 may be detected using only the first imaging device 13. For example, when the length of the belt 6 is 1 m and there is an inclination of 1 mm, it is sufficient to detect the first distance 22 of 0.2 mm for the first shooting range 19 of 20 mm x 20 mm. Even with this method, when the belt 6 meanders, the robot 15 can perform work on the target object without needing to correct the belt 6. [Explanation of symbols]

[0075] 3...belt conveyor as conveyor, 6...belt, 6a...center line as line, 9...first direction, 11...work as target, 12...first rotary encoder as detection unit, 13...first imaging device as detection unit and imaging device, 14...second imaging device as detection unit and imaging device, 15...robot, 18...second direction, 19a...first reference position as detection reference position, 21a...second reference position as detection reference position, 22, 54...first distance, 24...virtual line, 26...second distance, 42...photography control unit as detection unit, 43...position correction calculation unit as detection unit and calculation unit, 52...first length measuring device as detection unit and length measuring device, 53...second length measuring device as detection unit and length measuring device.

Claims

1. Control of robots that perform tasks on objects transported by a moving conveyor belt The method is as follows: an inclination between a first direction serving as a reference for the movement of the belt and a direction in which the belt is moving; At the detection reference position, the belt advances in a second direction perpendicular to the first direction. A first distance, which is a distance between a line along the direction and the detection reference position, is detected by a detection unit. 、 Based on the inclination detected by the detection unit and the first distance, The object is moved by the conveyor to a second position a second distance away in the first direction. Calculating the position of the object at The robot performs an operation on the object at the calculated second position, the detection unit is an imaging device, The line along the direction in which the belt moves is the center line of the belt. A method for controlling a robot.

2. A method for controlling a robot according to claim 1, comprising: The detection units are provided at both ends of the belt in the first direction before passing through the detection reference position. along the direction in which the belt travels in the second direction with respect to a virtual line extending in the first direction The inclination between the first direction and the direction in which the belt is moving is detected by detecting the position of the line. A method for controlling a robot, comprising the steps of: detecting a position of the robot;

3. A conveyor along which a belt carrying an object moves to transport the object; an inclination between a first direction serving as a reference for the movement of the belt and a direction in which the belt is moving; At the detection reference position, the belt advances in a second direction perpendicular to the first direction. a detection unit that detects a first distance, which is a distance between a line along a direction and the detection reference position; Based on the inclination detected by the detection unit and the first distance, The object is moved by the conveyor to a second position a second distance away in the first direction. a calculation unit for calculating the position of the object when the a robot that performs work on the object at two positions; the detection unit is an imaging device, The line along the direction in which the belt moves is the center line of the belt. A robot system.

Images