Control method and control device for a robot system

Abstract

To provide a control method and a control device of a robot system that can perform conveyance of an object with high accuracy.SOLUTION: A control method of a robot system, which holds an object being conveyed by a conveying device and conveys the held object to a target position, includes: a conveyance starting position predicting step of determining a predicted position at which conveyance of the object to the target position is started; a conveyance route generating step of generating a conveyance route for the object from the predicted position to the target position; a conveyance starting step of starting conveyance of the held object to the target position; and a correcting step of correcting the conveyance route, using a difference between a starting position at which the conveyance is started and the predicted position.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a control method and a control device for a robot system.

Background Art

[0002] For example, the tracking control method of a robot described in Patent Document 1 includes steps of continuously imaging a workpiece conveyed by a conveyor with a camera disposed directly above the conveyor, and detecting the position and conveyance speed of the workpiece based on the imaging result; and repeatedly calculating and estimating a target position of a tracking operation from the conveyance speed of the workpiece and the operation time of the robot.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in Patent Document 1, even if the robot can start tracking a workpiece conveyed by a conveyor, thereafter, the robot may not be able to pick up the workpiece and convey the picked-up workpiece to a target position. In particular, when the conveyance path after pickup is predetermined, if the actual position where conveyance after pickup starts deviates from the starting point of the conveyance path, there is a problem that this deviation directly leads to a deviation from the target position.

Means for Solving the Problems

[0005] A control method for a robot system according to the present invention is a control method for a robot system that holds an object conveyed by a conveying device and conveys the held object to a target position, A transport start position prediction step to determine a predicted position where the transport of the object to the target position will begin, A transport path generation step that generates a transport path for the object from the predicted position to the target position, A transport start step in which the transport of the held object to the target position is initiated, The method includes a correction step of correcting the transport path using the difference between the starting position where the transport was initiated and the predicted position.

[0006] The control device of the present invention is a control device for a robot system that holds an object being transported by a transport device and transports the held object to a target position, A transport start position prediction step to determine a predicted position where the transport of the object to the target position will begin, A transport path generation step that generates a transport path for the object from the predicted position to the target position, A transport start step in which the transport of the held object to the target position is initiated, A correction step is performed to correct the transport path using the difference between the starting position where the transport was initiated and the predicted position. [Brief explanation of the drawing]

[0007] [Figure 1] This is an overall configuration diagram of a robot system according to a preferred embodiment. [Figure 2] This flowchart shows the control method for the robot system. [Figure 3] This is a front view showing the state when the conveying device has started transporting the workpiece. [Figure 4] This is a front view showing the imaging unit capturing an image of a workpiece. [Figure 5] This is a top view showing the generated transport path. [Figure 6] This is a front view showing the robot holding the workpiece. [Figure 7] This is a top view showing how positional deviations occur at the target location. [Figure 8]This is a top view showing the transport path for correction. [Figure 9] This is a top view showing the transport path corrected by the first correction method. [Figure 10] This is a top view showing the transport path corrected by the second correction method. [Figure 11] This is a top view showing the transport path corrected by the third correction method. [Figure 12] This figure shows an example of a graphic interface. [Modes for carrying out the invention]

[0008] The control method and control device for the robot system of the present invention will be described in detail below based on the embodiments shown in the accompanying drawings.

[0009] Figure 1 is an overall configuration diagram of a robot system according to a preferred embodiment. Figure 2 is a flowchart showing the control method of the robot system. Figure 3 is a front view showing the state in which the transport device has started transporting the workpiece. Figure 4 is a front view showing the imaging unit imaging the workpiece. Figure 5 is a top view showing the generated transport path. Figure 6 is a front view showing the robot holding the workpiece. Figure 7 is a top view showing the positional deviation of the target position. Figure 8 is a top view showing a corrective transport path. Figure 9 is a top view showing the transport path corrected by the first correction method. Figure 10 is a top view showing the transport path corrected by the second correction method. Figure 11 is a top view showing the transport path corrected by the third correction method. Figure 12 is a diagram showing an example of a graphic interface.

[0010] The robot system 1 shown in Figure 1 comprises a robot 2, an imaging unit 3, a control device 4, a transport device 6, and a display device 8. The robot 2, imaging unit 3, and transport device 6 have all been calibrated, and their relative positions to each other are known.

[0011] In the robot system 1, the conveying device 6 conveys the work W as an object along the conveying direction A, the control device 4 detects the conveying status of the work W based on the image G acquired by the imaging unit 3 and the conveying speed of the work W, and based on the detected conveying status, the robot 2 holds the work W being conveyed while traveling parallel (tracking) to the work W and conveys the held work W to the target position. In addition, in the present embodiment, as shown in FIG. 1, the work W is conveyed while being housed in a box-shaped case C. However, it is not limited to this, and for example, the work W may be conveyed in an exposed state.

[0012] As shown in FIG. 1, the robot 2 is a six-axis vertical articulated robot having six drive shafts, and includes a base body 21, a robot arm 22 rotatably connected to the base body 21, and an end effector 23 attached to the tip of the robot arm 22. The robot arm 22 is a robotic arm in which a plurality of arms 221, 222, 223, 224, 225, 226 are rotatably connected, and is provided with six joints J1 to J6. Among these, joints J2, J3, and J5 are bending joints, and joints J1, J4, and J6 are twisting joints. The end effector 23 is appropriately selected according to the target work. In the illustrated configuration, the end effector 23 is configured to adsorb and hold the work W by an air chuck.

[0013] In addition, a motor M and an encoder E for detecting the rotation amount of the motor M are installed in each of the joints J1, J2, J3, J4, J5, and J6. During the operation of the robot system 1, the control device 4 performs servo control (feedback control) to match the rotation angles of the joints J1 to J6 indicated by the output of the encoder E with the control targets for each of the joints J1 to J6.

[0014] The conveying device 6 is a belt conveyor and includes a belt 62, a conveying roller 63 for sending the belt 62, a motor 61 for driving the conveying roller 63, and an encoder 64 that outputs a signal corresponding to the rotation amount of the belt 62 to the control device 4. During the operation of the robot system 1, the control device 4 performs servo control (feedback control) to make the conveying speed of the workpiece W indicated by the output of the encoder 64 match the target conveying speed, which is the control target.

[0015] The imaging unit 3 is a camera that images the workpiece W from above the conveying device 6 and outputs the captured image to the control device 4. The imaging area of the imaging unit 3 is located upstream of the working area of the robot 2 in the conveying direction A. The position of each pixel in the image output from the imaging unit 3 is associated with the position in the conveying path by the control device 4. Therefore, when the workpiece W exists within the viewing angle of the imaging unit 3, based on the position of the workpiece W in the image of the imaging unit 3, the coordinates (position) of the workpiece W at the time when the image was captured (hereinafter, also referred to as "image acquisition time Ti") can be specified.

[0016] The control device 4 controls the driving of the robot 2, the imaging unit 3, and the conveying device 6 respectively. The control device 4 is composed of, for example, a computer and includes a processor (CPU) for processing information, a memory communicably connected to the processor, and an external interface for connecting to an external device. Various programs executable by the processor are stored in the memory, and the processor can read and execute various programs and the like stored in the memory. Note that some or all of the components of the control device 4 may be arranged inside the housing of the robot 2. Also, the control device 4 may be composed of a plurality of processors.

[0017] The configuration of the robot system 1 has been briefly described above. Such a robot system 1 operates as follows. First, the control device 4 operates the conveying device 6 so that the conveying speed of the workpiece W detected based on the output of the encoder 64 becomes the target conveying speed. Conveying device 6The control device 4 controls the drive of the robot 2. In this state, the workpiece W is supplied to the transport device 6, and the transport device 6 starts transporting the workpiece W. Next, the control device 4 uses the imaging unit 3 to image the workpiece W as it passes through the imaging area and acquires an image G in which the workpiece W is captured. Next, the control device 4 detects the coordinates of the workpiece W at the time the image G was acquired from the image G. Next, the control device 4 calculates the position of the workpiece W at each future time from the coordinates of the workpiece W at the time the image G was acquired and the transport speed of the workpiece W, and calculates a control signal for the robot 2 based on the calculated position. Then, the control device 4 drives the robot 2 with the calculated control signal and causes the robot 2 to perform a predetermined operation on the workpiece W that is being transported.

[0018] Next, a predetermined operation will be described. In this embodiment, the predetermined operation includes a holding step of holding (picking) a workpiece W being transported by the transport device 6, and a transport step of transporting the held workpiece W to a target position Pe. The control method of the robot system 1 when performing such an operation includes a workpiece transport step S1 in which the transport device 6 transports the workpiece W, a transport start position prediction step S2 in which a predicted position Ps is determined to start the transport of the workpiece W to the target position Pe, a transport path generation step S3 in which a transport path E1 of the workpiece W is generated from the predicted position Ps to the target position Pe, a workpiece holding step S4 in which the workpiece W is held, a transport start step S5 in which the transport of the held workpiece W to the target position Pe is started, and a correction step S6 in which the transport path E1 is corrected using the difference between the start position Ps' in which the transport of the workpiece W was actually started in the transport start step S5 and the predicted position Ps predicted in the transport start position prediction step S2. Hereinafter, each of these steps S1 to S6 will be described in detail based on the flowchart shown in Figure 2.

[0019] [Workpiece transport step S1] First, the control device 4 starts driving the transport device 6 and adjusts the transport speed Vs of the workpiece W, as indicated by the output of the encoder 64, to match the target transport speed. As a result, as shown in Figure 3, the workpiece W placed on the transport device 6 is transported at the target transport speed. The method of supplying the workpiece W to the transport device 6 is not particularly limited and can be done using, for example, a robot or a parts feeder. Alternatively, it may be supplied manually by an operator.

[0020] [Prediction step S2 of transport start position] When the transport device 6 starts transporting the workpiece W, the control device 4 uses the imaging unit 3 to image the workpiece W as it passes through the imaging area and acquires an image G of the workpiece W. Next, based on the acquired image G, the control device 4 determines the position (coordinates) of the workpiece W at the time the image G was acquired, i.e., the image acquisition time Ti. Then, as shown in Figure 4, the control device 4 determines the predicted position Ps, which is the position to start the transport start step S5, based on the image acquisition time Ti, the position of the workpiece W at the image acquisition time Ti, the transport speed Vs, the time required for the workpiece holding step S4, etc. Note that the predicted position Ps refers to the position of the robot 2, and more specifically, it refers to the position of the TCP (tool center point) set at the tip of the robot arm 22.

[0021] However, the method for determining the predicted position Ps is not particularly limited. For example, the method described above uses a preset target transport speed Vs for the transport speed Vs of the workpiece W, but is not limited to this. For example, the control device 4 continuously images the workpiece W at a predetermined frame rate using the imaging unit 3 while the workpiece W passes through the imaging area, and acquires multiple images of the workpiece W. Next, the control device 4 may determine the position of the workpiece W in each image and determine the transport speed Vs of the workpiece W based on the amount of displacement of the workpiece W between images (the distance the workpiece W has traveled) and the frame rate.

[0022] [Transport route generation step S3] In the transport path generation step S3, the control device 4 generates a transport path E1 for the workpiece W from the predicted position Ps obtained in the transport start position prediction step S2 to the target position Pe, as shown in Figure 5, and sets the operation start time Ts to start the transport start step S5. The transport path E1 can be set appropriately based on the state of the workpiece W, the range of motion of the robot 2, the surrounding environment of the robot 2 (presence or absence of obstacles, etc.), etc. The transport path E1 is a parameter that defines the direction of movement and the distance of movement of the robot 2.

[0023] [Workpiece holding step S4] In the workpiece holding step S4, the control device 4 controls the drive of the robot 2, as shown in Figure 6, to hold the workpiece W being transported on the transport device 6 with the end effector 23. Specifically, the end effector 23 is held by moving it parallel to the workpiece W and positioning it directly above the workpiece W, lowering the end effector 23 to make contact with the workpiece W, and then using the end effector 23 to hold the workpiece W by suction. As mentioned above, since the workpiece W is housed in the case C, the end effector 23 continues to move parallel to the workpiece W even after holding the workpiece W. If the parallel movement is stopped, the workpiece W may collide with the case C, potentially causing damage to the workpiece W or operational errors.

[0024] [Transportation start step S5] In the transport start step S5, the control device 4 first determines whether the operation start time Ts has arrived. If it has arrived, it starts driving control of the robot 2 so that the workpiece W moves along the transport path E1 generated in the transport path generation step S3. However, due to various reasons such as variations in the time required for the calculation processing of the control device 4, variations in the time required for communication between each part, and variations in the transport speed Vs relative to the target transport speed, the starting position Ps' at which step S5 is actually started may deviate from the predicted position Ps predicted in the transport start position prediction step S2, as shown in Figure 7. In particular, in this embodiment, when the robot 2 is running parallel to the workpiece W to avoid contact between the case C and the workpiece W, and then the next operation, i.e., transport to the target position Pe of the workpiece W is started, the starting position Ps' is more likely to deviate from the predicted position Ps.

[0025] If the starting position Ps' deviates from the predicted position Ps in this way, that deviation will occur at the target position Pe. In other words, the actual transport position Pe' will deviate from the target position Pe by the same amount as the deviation of the starting position Ps' from the predicted position Ps. Therefore, accurate transport operations cannot be performed. To address this, the control device 4 performs a correction step S6 to correct the transport path E1 based on the difference ΔPs (deviation) between the predicted position Ps and the starting position Ps' so that the transport position Pe' coincides with the target position Pe.

[0026] [Correction step S6] In the correction step S6, the control device 4 first determines the starting position Ps' at which the transport start step S5 was initiated. The method for determining the starting position Ps' is not particularly limited, but in this embodiment, it is determined based on the output from the encoders E of each joint J1, J2, J3, J4, J5, and J6 of the robot 2. This method allows the starting position Ps' to be determined easily and with high accuracy. Next, as shown in Figure 8, the control device 4 generates a correction transport path E2 to move the workpiece W from the starting position Ps' to the predicted position Ps. Next, the control device 4 corrects the transport path E1 using the correction transport path E2 in one of the following three ways. By correcting the transport path E1 using the correction transport path E2 in this way, the difference ΔPs between the predicted position Ps and the starting position Ps' can be easily canceled.

[0027] -First correction method- In the first correction method, as shown in Figure 9, the control device 4 combines the transport path E1 and the correction transport path E2, that is, adds the transport path E1 and the correction transport path E2 together to generate a new transport path E3. At this time, the robot 2 has already started moving based on the transport path E1. Therefore, the transport path E3 is generated little by little as the robot 2 transports the workpiece W, and each time the robot 2 receives the generated transport path E3, it updates the transport path E3 and transports the workpiece W. As a result, the difference ΔPs between the predicted position Ps and the starting position Ps' is canceled, and the workpiece W can be transported to the target position Pe.

[0028] This first correction method allows for a shorter total travel distance of the workpiece W compared to the second and third correction methods described later, thereby reducing the time required for transport (cycle time).

[0029] -Second correction method- In the second correction method, as shown in Figure 10, the control device 4 transports the workpiece W along the correction transport path E2 before transporting the workpiece W along the transport path E1. In other words, the control device 4 performs a correction by adding the correction transport path E2 before the transport path E1, and generates a new transport path E3. As a result, the difference ΔPs between the predicted position Ps and the starting position Ps' is canceled, and the workpiece W can be transported to the target position Pe.

[0030] This second correction method ensures that the approach direction to the target position Pe remains unchanged, and appropriate transport can be performed even when there are limitations on the approach direction to the target position Pe, such as when it is surrounded by walls on three sides. Furthermore, it makes it easier for the user to predict the route, making it easier to avoid problems such as contact with obstacles during transport.

[0031] -Third correction method- In the third correction method, as shown in Figure 11, the control device 4 transports the workpiece W along the transport path E1, and then transports the workpiece W along the correction transport path E2. In other words, the control device 4 performs a correction by adding the correction transport path E2 after the transport path E1, and generates a new transport path E3. As a result, the difference ΔPs between the predicted position Ps and the starting position Ps' is canceled, and the workpiece W can be transported to the target position Pe.

[0032] This third correction method ensures that the starting direction of movement from the starting position Ps' remains unchanged from that of the transport path E1, allowing for proper transport even when there are restrictions on the starting direction, such as when the area is surrounded by walls on three sides. Furthermore, it makes it easier to predict the path, making it easier to avoid problems such as contact with obstacles during transport.

[0033] The control device 4 corrects the transport path E1 using one of the three correction methods described above, and then controls the drive of the robot 2 so that the workpiece W is transported along the corrected transport path E3. With this control method, even if there is a discrepancy between the predicted position Ps and the starting position Ps', this discrepancy is canceled out during the transport of the workpiece W, and the workpiece W can be transported to the target position Pe. Therefore, the workpiece W can be transported with excellent accuracy.

[0034] Returning to Figure 2, in this correction step S6, the control device 4 first determines the starting position Ps' based on the output from the encoders E of each joint J1, J2, J3, J4, J5, and J6 of the robot 2 as step S61. Next, the control device 4 determines the difference ΔPs between the predicted position Ps and the starting position Ps' as step S62. Next, the control device 4 determines whether to correct the transport path E1 based on the result of comparing the difference ΔPs with a preset tolerance range as step S63. The preset tolerance range can be a tolerance range set by the user, a tolerance range stored in the memory unit of the robot from the time of shipment, or an optimal tolerance range stored in the memory unit of the robot through machine learning.

[0035] In step S63, if it is determined that the transport path E1 does not need to be corrected, the control device 4 controls the drive of the robot 2 so that the workpiece W moves along the transport path E1 without correcting the transport path E1. For example, if the difference ΔPs is within the allowable range, the control device 4, in step S64, controls the drive of the robot 2 so that the workpiece W moves along the transport path E1 without correcting the transport path E1. In this way, by not correcting the transport path E1 when the difference ΔPs is within the allowable range, the workpiece W can be quickly transported to the target position Pe, and the transport time (cycle time) can be shortened.

[0036] In response to this, if it is determined in step S63 that the transport path E1 should be corrected, the control device 4 generates a corrective transport path E2 for transporting the workpiece W from the starting position Ps' to the predicted position Ps in step S65. For example, if the difference ΔPs is outside the acceptable range, the control device 4 generates a corrective transport path E2 for transporting the workpiece W from the starting position Ps' to the predicted position Ps in step S65. Next, in step S66, the control device 4 selects one of the first, second, and third correction methods described above as a method for correcting the transport path E1. The selection method is not particularly limited, but in this embodiment, the user is allowed to select it in advance.

[0037] For example, in this embodiment, the display device 8 displays a graphic interface 80 as shown in Figure 12, and is configured to accept input from the user via the graphic interface 80. The graphic interface 80 displays a field for selecting one of three correction methods: a first correction method, a second correction method, and a third correction method. Therefore, the user can select one of the three correction methods, taking into consideration the work content, work environment, etc. However, it is not limited to this, and the control device 4 may automatically set the correction method based on the work content, work environment, etc. By providing a configuration that allows the correction method to be selected in this way, the transport path E1 can be corrected using a method appropriate to the situation, thereby enabling more reliable transport of the workpiece W.

[0038] If the first correction method is selected, the control device 4, in step S671, combines the transport path E1 and the correction transport path E2 to generate a new transport path E3. Next, in step S672, the control device 4 controls the drive of the robot 2 so that the workpiece W moves along the transport path E3. As a result, the workpiece W is transported to the target position Pe. With this method, even if the starting position Ps' deviates from the predicted position Ps, the difference ΔPs between the predicted position Ps and the starting position Ps' is canceled out, and the workpiece W can be transported to the target position Pe.

[0039] If the second correction method is selected, the control device 4 controls the drive of the robot 2 in step S681 so that the workpiece W moves along the correction transport path E2. Next, the control device 4 controls the drive of the robot 2 in step S682 so that the workpiece W moves along the transport path E1. As a result, the workpiece W is transported to the target position Pe. With this method, even if the starting position Ps' deviates from the predicted position Ps, the difference ΔPs between the predicted position Ps and the starting position Ps' is canceled out, and the workpiece W can be transported to the target position Pe.

[0040] If the third correction method is selected, the control device 4 controls the drive of the robot 2 in step S691 so that the workpiece W moves along the transport path E1. Next, the control device 4 controls the drive of the robot 2 in step S692 so that the workpiece W moves along the correction transport path E2. As a result, the workpiece W is transported to the target position Pe. With this method, even if the starting position Ps' deviates from the predicted position Ps, the difference ΔPs between the predicted position Ps and the starting position Ps' is canceled out, and the workpiece W can be transported to the target position Pe.

[0041] The robot system 1 has been described above. As previously mentioned, the control method for this robot system 1 is a method for holding a workpiece W as an object to be transported by the transport device 6 and transporting the held workpiece W to a target position Pe, and includes: a transport start position prediction step S2 for determining a predicted position Ps to start transporting the workpiece W to the target position Pe; a transport path generation step S3 for generating a transport path E1 for the workpiece W from the predicted position Ps to the target position Pe; a transport start step S5 for starting the transport of the held workpiece W to the target position Pe; and a correction step S6 for correcting the transport path E1 using the difference ΔPs between the start position Ps' and the predicted position Ps. With this control method, even if there is a discrepancy between the start position Ps' and the predicted position Ps, the discrepancy is canceled during the transport of the workpiece W, and the workpiece W can be transported to the target position Pe. Therefore, the workpiece W can be transported with excellent accuracy.

[0042] Furthermore, as mentioned above, in the control method of the robot system 1, the correction step S6 is performed based on the result of comparing the difference ΔPs with a preset tolerance range. For example, when the difference ΔPs is outside the tolerance range, the transport path E1 is corrected, and when the difference ΔPs is within the tolerance range, the transport path E1 is not corrected. In this way, if the transport path E1 is corrected as a result of comparing the difference ΔPs with the preset tolerance range, the difference ΔPs between the predicted position Ps and the starting position Ps' can be canceled and the workpiece W can be transported to the target position Pe. If the transport path E1 is not corrected, the workpiece W can be transported to the target position Pe quickly, and the time required for transport (cycle time) can be shortened.

[0043] Furthermore, as mentioned above, in correction step S6, a correction transport path E2 is generated from the starting position Ps' to the predicted position Ps, and the transport path E1 is corrected using the correction transport path E2. This makes it easy to cancel out the difference ΔPs between the predicted position Ps and the starting position Ps'.

[0044] Furthermore, as mentioned above, in correction step S6, the transport path E1 is corrected by combining the transport path E1 and the corrected transport path E2. With this correction method, the total travel distance of the workpiece W can be shortened compared to the second and third correction methods, and the time required for transport (cycle time) can be reduced.

[0045] Furthermore, as mentioned above, in correction step S6, the transport path E1 is corrected by adding a corrective transport path E2 after the transport path E1. With this correction method, the direction of movement from the starting position Ps' remains the same as that of the transport path E1, and appropriate transport can be performed even when there are restrictions on the direction of movement, such as when the area is surrounded by walls on three sides. In addition, the path becomes easier to predict, making it easier to avoid problems such as contact with obstacles during transport.

[0046] Furthermore, as mentioned above, in correction step S6, the transport path E1 is corrected by adding a corrective transport path E2 before the transport path E1. With this correction method, the approach direction to the target position Pe does not change, and appropriate transport can be performed even when there are restrictions on the approach direction to the target position Pe, such as when it is surrounded by walls on three sides. In addition, the path becomes easier to predict, making it easier to avoid problems in advance, such as contact with obstacles during transport.

[0047] Furthermore, as mentioned above, the system provides multiple methods for correcting the transport path E1, and in correction step S6, the transport path E1 is corrected using one of the methods pre-selected from the multiple methods. By providing a configuration that allows selection of the correction method, the transport path E1 can be corrected using a method appropriate to the situation, thereby enabling more reliable transport of the workpiece W.

[0048] As mentioned above, the control device 4 is a control device for a robot system 1 that holds a workpiece W as an object to be transported by the transport device 6 and transports the held workpiece W to a target position Pe. The control device 4 performs the following steps: a transport start position prediction step S2 to determine a predicted position Ps to start transporting the workpiece W to the target position Pe; a transport path generation step S3 to generate a transport path E1 for the workpiece W from the predicted position Ps to the target position Pe; a transport start step S5 to start transporting the held workpiece W to the target position Pe; and a correction step S6 to correct the transport path E1 using the difference ΔPs between the start position Ps' and the predicted position Ps. With such a control device 4, even if there is a discrepancy between the start position Ps' and the predicted position Ps, the discrepancy is canceled during the transport of the workpiece W, and the workpiece W can be transported to the target position Pe. Therefore, the workpiece W can be transported with excellent accuracy.

[0049] Although the robot system control method and control device of the present invention have been described above based on the illustrated embodiments, the present invention is not limited thereto, and the configuration of each part can be replaced with any configuration having a similar function. Furthermore, any other components may be added to the present invention. [Explanation of Symbols]

[0050] 1...Robot system, 2...Robot, 21...Base, 22...Robot arm, 221...Arm, 222...Arm, 223...Arm, 224...Arm, 225...Arm, 226...Arm, 23...End effector, 3...Imaging unit, 4...Control device, 6...Transport device, 61...Motor, 62...Belt, 63...Transport roller, 64...Encoder, 8...Display device, 80...Graphic interface, A...Transport direction, C...Case, E...Encoder, E1...Transport path, E2...Correction transport path, E3...Transport path, G...Image, J1...Joint, J2...Joint, J3...Joint, J4...Joint, J5...Joint, J6 ...joint, M...motor, Pe...target position, Pe'...transport position, Ps...predicted position, Ps'...start position, S1...workpiece transport step, S2...transport start position prediction step, S3...transport path generation step, S4...workpiece holding step, S5...transport start step, S6...correction step, S61...step, S62...step, S63...step, S64...step, S65...step, S66, S671...step, S672...step, S681...step, S682...step, S691...step, S692...step, Ti...image acquisition time, Ts...operation start time, W...workpiece, ΔPs...difference

Claims

1. A control method for a robot system that holds an object being transported by a transport device and transports the held object to a target position, A transport start position prediction step to determine a predicted position where the transport of the object to the target position will begin, A transport path generation step involves generating a transport path for the object from the predicted position to the target position, and setting an operation start time to begin transporting the object to the target position. A transport start step in which, when the aforementioned operation start time arrives, the transport of the held object to the aforementioned target position is started based on the transport path, A method for controlling a robot system, characterized by including a correction step of correcting the transport path using the difference between the starting position where the transport was initiated and the predicted position.

2. The method for controlling a robot system according to claim 1, wherein the correction step is performed based on the result of comparing the difference with a preset tolerance range.

3. The control method for a robot system according to claim 1, wherein the correction step involves generating a correction transport path from the starting position to the predicted position, and correcting the transport path using the correction transport path.

4. The control method for a robot system according to claim 3, wherein the transport path is corrected by combining the transport path and the corrected transport path in the correction step.

5. The control method for a robot system according to claim 3, wherein the correction step involves correcting the transport path by adding the corrective transport path after the transport path.

6. The control method for a robot system according to claim 3, wherein the correction step involves correcting the transport path by adding the corrective transport path before the transport path.

7. The system includes multiple methods for correcting the aforementioned transport path. The control method for a robot system according to claim 1, wherein the correction step involves correcting the transport path using one of the correction methods selected in advance from a plurality of correction methods.

8. A control device for a robot system that holds an object being transported by a transport device and transports the held object to a target position, A transport start position prediction step to determine a predicted position where the transport of the object to the target position will begin, A transport path generation step involves generating a transport path for the object from the predicted position to the target position, and setting an operation start time to begin transporting the object to the target position. A transport start step in which, when the aforementioned operation start time arrives, the transport of the held object to the aforementioned target position is started based on the transport path, A control device characterized by performing a correction step of correcting the transport path using the difference between the starting position where the transport was initiated and the predicted position.

Images