Robot control methods, robot systems

Abstract

To provide a robot control method that can reliably attach an object even if the object is not fixed in place. [Solution] A robot control method comprising a robot having an end-effector and a force sensor provided at the tip of a robot arm, and a control device, wherein the control device controls the operation of the robot when attaching an object to the end-effector, the method includes: (1) moving the position of the end-effector in a first direction in a first posture state; (2) if the end-effector comes into contact with the object based on the detection value of the force sensor, performing a tracing motion with the end-effector on the object; (3) determining whether the end-effector has moved a predetermined distance or more in the first direction; and (4) if the determination is no, moving the end-effector in a second direction opposite to the first direction to move it away from the object, and repeating steps (1) to (4) with respect to the object.

Description

Technical Field

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

Background Art

[0002] For example, Patent Document 1 discloses an assembling method in which a flexible assembly is deformed by a robot and assembled to an object to be assembled. According to this document, with the object to be assembled fixed to a fixing jig, the assembly held by a robot arm is brought into contact with the object to be assembled in an inclined posture different from the assembled state, and then the assembly is rotated to perform the assembly.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] [[ID=……]] However, in the assembling method of Patent Document 1, when the object to be assembled is not fixed, if the posture of the assembly is rotated, the position of the object to be assembled will shift, and there is a problem that it is difficult to perform the work of properly assembling and inserting. For example, in a dispensing system, it is necessary to attach a disposable chip to a pipette at the tip of a robot arm, but the chip is stored in a rack with play, and it was difficult to properly attach the chip using the above assembling method. That is, there has been a demand for a method for controlling a robot that can reliably attach an object even when the object is not fixed.

Means for Solving the Problems

[0005] A robot control method according to one aspect of the present invention comprises a robot arm, a robot having an end-effector and a force sensor provided at the tip of the robot arm, and a control device for controlling the movement of the robot, wherein the control device controls the movement of the robot when attaching a work object to the end-effector, and includes: (1) moving the position of the end-effector in a first direction in a first posture state; (2) if the end-effector comes into contact with the object based on the detection value of the force sensor, performing a tracking motion with the end-effector on the object; (3) determining whether the end-effector has moved a predetermined distance or more in the first direction; and (4) if the determination is no, moving the end-effector in a second direction opposite to the first direction to move it away from the object, and repeating (1) to (4) again with respect to the object.

[0006] A robot system according to one aspect of the present invention comprises a robot arm, a robot having an end-effector and a force sensor provided at the tip of the robot arm, and a control device for controlling the movement of the robot, wherein the control device causes the robot to move the position of the end-effector in a first direction while in a first posture when attaching a work object to the end-effector, and based on the value detected by the force sensor, if the end-effector comes into contact with the object, the control device causes the end-effector to perform a tracing motion with respect to the object, and determines whether the end-effector has moved a predetermined distance or more in the first direction, and if the determination is no, moves the end-effector in a second direction opposite to the first direction, and repeats this until the end-effector has moved a predetermined distance or more in the determination. [Brief explanation of the drawing]

[0007] [Figure 1] A schematic diagram of the robot system according to Embodiment 1. [Figure 2] A perspective view of a robot to be installed in a robotic system. [Figure 3] Block diagram of the control unit. [Figure 4]A flowchart illustrating the procedure for attaching the chip. [Figure 5] A diagram showing one aspect of the chip attachment process. [Figure 6] A diagram showing one aspect of the chip attachment process. [Figure 7] A diagram showing one aspect of the chip attachment process. [Figure 8] A graph showing force sensor detection data when the chip is successfully attached. [Figure 9] A diagram illustrating one example of a failed installation. [Figure 10] A graph showing force sensor detection data when chip installation fails. [Figure 11] A diagram illustrating how the starting position of a copying motion can be changed. [Modes for carrying out the invention]

[0008] Embodiment 1 ***Dispensing System Configuration*** Figure 1 is a schematic diagram of the robot system according to Embodiment 1. Figure 2 is a perspective view of the robot mounted on the robot system. The configuration of the robot system 200 according to this embodiment will be explained using Figures 1 and 2. Each figure shows the three mutually orthogonal axes: the X-axis, Y-axis, and Z-axis. In this embodiment, the Z-direction refers to both the Z-positive and Z-negative directions along the Z-axis. The same applies to the X-direction and Y-direction. In a preferred example, the Z-direction is defined as the vertical direction, with the Z-positive direction also referred to as "up" and the Z-negative direction as "down." However, the Z-direction is not limited to being defined as the vertical direction. Furthermore, in the following explanation, "position" refers to the translational position in the XYZ orthogonal coordinate system, and attitude changes are assumed to involve rotational motion. In the following figures, dimensions and scales may differ from actual dimensions for the sake of clarity.

[0009] The robot system 200 shown in Figure 1 is an example of laboratory automation technology that automates experimental operations related to ink development, and is a dispensing system consisting of a dispensing device 100, a control device 80, and the like. It should be noted that the robot system 200 is not limited to ink development; it can be applied to applications requiring high-precision dispensing, and is suitable for use in life science fields such as medicine and biotechnology.

[0010] The dispensing device 100 consists of a robot 40, a reagent holder 71, a container holder 73, a reagent table 72, a lid opening / closing unit 76, a container table 75, a lid opening / closing unit 74, a pipette holder 77, a tip holder 78, an electronic balance 79, and the like.

[0011] As shown in Figure 2, in a preferred example, the robot 40 employs a vertical articulated robot with six drive axes, capable of performing complex movements similar to those of a human arm. The robot 40 comprises a base 210 fixed to the floor, a robot arm 220 connected to the base 210, and hands 5a and 5b attached to the end arm 226.

[0012] The robotic arm 220 is a robotic arm in which multiple arms 221, 222, 223, 224, 225, and 226 are rotatably connected, and it has six joints J1 to J6. Of these, joints J2, J3, and J5 are bending joints, and joints J1, J4, and J6 are torsional joints. In addition, each of joints J1, J2, J3, J4, J5, and J6 is equipped with a motor M, which is the drive source, and an encoder E that detects the amount of rotation of the motor M (the rotation angle of the arm).

[0013] A pair of hands 5a and 5b capable of gripping a cylindrical object are attached to the tip arm 226. A C-shaped recess for gripping the cylindrical object is provided at the tip of the hand 5a. A recess that mates with the recess of the hand 5a is provided at the tip of the hand 5b. The hands 5a and 5b are provided so that the gap between them can be adjusted according to the diameter of the cylindrical object. For example, in the example of FIG. 2, the cylindrical pipette 7 is being gripped by the hands 5a and 5b. The pipette 7 is a tip device and corresponds to an end effector. A chip 8 as an object is attached to the tip of the pipette 7.

[0014] The robot 40, in accordance with a command from the control device 80, after gripping the optimal pipette 7 according to the dispensing volume, as shown in FIG. 2, mounts the chip 8 on the tip of the pipette 7 and then performs the dispensing operation. The chip 8 is an object and is a disposable part that is replaced each time one reagent is dispensed. Note that the pipette 7 with the chip 8 attached is called a nozzle 10. Also, the hands 5a and 5b can grip a cylindrical object, and for example, can also suitably grip the reagent bottle 1 and the container 3. The hands 5a and 5b are also collectively referred to as the hand 5.

[0015] A force sensor 15 is attached between the tip arm 226 and the arm 225. The force sensor 15 detects one or both of the force or moment received by the hand 5. When the hand 5 is gripping the pipette 7, it detects one or both of the force or moment received by the pipette 7. The force sensor 15 uses a piezoelectric force sensor. The piezoelectric force sensor, for example, compared to an electrostatic method or a strain gauge method, has high rigidity and can reduce errors and improve accuracy. In a preferred example, a force sensor 15 using a crystal element as a piezoelectric element is used. Thereby, errors can be reduced and accuracy can be improved. Note that the force sensor 15 is not limited to the piezoelectric method, and any sensor capable of detecting force or moment may be used. For example, a torque sensor or an inertial sensor unit may be used. Also, something other than crystal may be used as the piezoelectric element.

[0016] In other words, the robot system 200 includes a robot arm 220, a robot 40 having a pipette 7 and a force sensor 15 as tip devices provided at the tip of the robot arm 220, and a control device 80 that controls the operation of the robot 40.

[0017] Return to FIG. 1. As shown in FIG. 1, the dispensing device 100 is substantially square planar, and when the square is divided into four, the robot 40 is arranged in one section in the X plus direction and the Y minus direction. The hand 5 of the robot 40 is provided so as to be able to reach all of the remaining three sections. The test solution placement area 71 is arranged in one section in the X minus direction and the Y minus direction, and is a test solution placement area where a plurality of test solution bottles 1 are stocked. For example, in the example of FIG. 1, six types of test solutions from test solution bottle 1a to test solution bottle 1f are stocked. Each bottle contains a different test solution with different components. Let the test solution in test solution bottle 1a be the first test solution, the test solution in test solution bottle 1b be the second test solution, and so on, and the third to sixth test solutions are assumed to be contained in the order of the branch numbers of the test solution bottles. Note that the number of test solution bottles 1 is not limited to six, and may be a plurality of bottles, for example, 20 or more. Note that the test solution is also referred to as a liquid. In a preferred example, the test solution bottle 1 is made of glass. Note that it is not limited to being made of glass, and it may be made of plastic or pottery.

[0018] The container placement area 73 is arranged on the X minus side of the test solution placement area 71, and is a container placement area where a plurality of containers 3 are stocked. For example, in the example of FIG. 1, three empty containers 3 are arranged. Note that the number of containers 3 is not limited to three, and may be a plurality of containers, for example, 10 or more. In a preferred example, the container 3 is made of glass. Note that it is not limited to being made of glass, and it may be made of plastic or pottery. The reagent table 72 is located in a section in the X-minus direction and Y-plus direction, and is the stage on which the reagent bottles 1 containing the reagents to be dispensed are placed. The target reagent bottles 1 are grasped from the reagent storage area 71 by the robot 40 and set on the reagent table 72. The reagent bottles 1 set on the reagent table 72 are transported in the Y-plus direction by the lid opening / closing unit 76, the lids are removed, and then the bottles are placed back on the reagent table 72. After dispensing is completed, the lids are closed by the lid opening / closing unit 76 and then returned to the reagent storage area 71 by the robot 40.

[0019] The container table 75 is located on the X-plus side of the reagent table 72 and is the stage where empty containers 3 are placed. The target container 3 is grasped from the container storage area 73 by the robot 40 and set on the container table 75. The container 3 set on the container table 75 is transported in the Y-plus direction by the lid opening / closing unit 74, the lid is removed, and then it is placed back on the container table 75.

[0020] ***Pipet and tip arrangement*** The pipette holder 77 is located on the X-minus side of the reagent table 72 and is a pipette holder where multiple pipettes 7 are placed. The pipettes 7 are electric pipettes, and several types of pipettes with different suction capacities are prepared. For example, in the example in Figure 1, pipettes 7a, 7b, and 7c are arranged in this order in the Y-plus direction. The suction volume of pipette 7a is smallest, and that of pipette 7c is largest. The suction volume of pipette 7b falls between that of pipette 7a and pipette 7c. Pipettes 7a, b, and c have different diameters, so different sized tips are fitted to them.

[0021] A tip storage area 78 is located in the Y-minus direction of the pipette storage area 77. Multiple types of tip boxes are placed in the tip storage area 78. For example, in the example shown in Figure 1, tip boxes 78a, 78b, and 78c are arranged in this order in the X-plus direction. Nine pipette tips 8a are arranged in a matrix in tip box 78a. The tip box 78a is precisely positioned in a designated location on the dispensing device 100, and the reference position coordinates of each tip 8a are stored in the storage unit 35 of the computer 30. The chip box 78a is a storage rack for the chips 8a, and in the preferred example, the chip box 78a is the original box that the chips came in. Note that the number of chips 8a stored in the chip box 78a is not limited to 9; multiple chips can be arranged in rows and columns, for example, 8 rows x 12 columns = 96 chips.

[0022] The tip box 78b contains nine pipette tips 8b arranged in a matrix. The tip box 78b is precisely positioned in a designated location on the dispensing device 100, and the reference position coordinates of each tip 8b are stored in the memory unit 35 of the computer 30. The rest is the same as described for tip box 78a. The tip box 78c contains nine pipette tips 8c arranged in a matrix. The tip box 78c is precisely positioned in a designated location on the dispensing device 100, and the reference position coordinates of each tip 8c are stored in the memory unit 35 of the computer 30. The rest is the same as described for tip box 78a. Although not shown in the diagram, a disposal area for the tips 8 is provided near the pipette holder 77.

[0023] The electronic balance 79 is positioned in one section in the X-positive and Y-positive directions and is an electronic balance that accurately weighs the mass of container 3. In a preferred example, by weighing container 3 before dispensing and weighing container 3 after dispensing, it is possible to confirm whether the desired mass has been dispensed.

[0024] ***Overview of the control system*** Figure 3 is a block diagram of the control device. The control device 80 consists of a computer 30 and a robot controller 50. In a preferred example, the computer 30 is a notebook computer equipped with a display unit 31 consisting of a liquid crystal panel and an operation unit 32 consisting of a keyboard. The operation unit 32 may be a touch panel provided on the display unit 31 or a mouse. The computer 30 also includes an IF unit 33, a control unit 34, and a storage unit 35.

[0025] The IF unit 33 is an interface unit with the robot controller 50 and is equipped with multiple connection terminals and interface circuits. The control unit 34 consists of one or more processors and is connected to various parts of the computer 30, including the storage unit 35, via bus lines.

[0026] The memory unit 35 is comprised of RAM (Random Access Memory) and ROM (Read Only Memory). The RAM is used for temporary storage of various data, while the ROM stores control programs for controlling the operation of the robot 40, as well as associated data. The control programs include a startup program that instructs the order and content of the processing when starting the robot 40, and a dispensing program 75a, which includes the chip mounting program 75b described later. The associated data includes chip coordinate data 75d, coordinate data for tracing, and a dispensing recipe file 75c. The dispensing recipe file 75c is a recipe file that specifies a list of reagents to be dispensed and the amount (g) to be dispensed for each reagent. Since the nozzle 10 manages by volume, the specific gravity of each reagent is also stored in the dispensing recipe file, and a volume corresponding to the specific gravity is aspirated during dispensing.

[0027] The robot controller 50 is a device that provides overall control of the robot 40, lid opening / closing unit 74, lid opening / closing unit 76, container table 75, electronic balance 79, and other components. The robot controller 50 is a control circuit configured with one or more processors, and it provides overall control of the operation of each part of the dispensing device 100 by operating according to a control program stored in a memory circuit (not shown). The robot controller 50 is connected to the computer 30 and controls each part, including the robot 40, according to the dispensing recipe file in the computer 30, causing the dispensing device 100 to perform the dispensing operation. Each time dispensing is performed, the tip attachment program 75b, described later, is executed, and the tip 8 is attached to the pipette 7. Peripheral equipment such as the pipette 7 and electronic balance 79 are controlled by the computer 30 upon request from the robot controller 50. In addition, detection data from the force sensor 15 is transmitted to the computer 30 via the robot controller 50.

[0028] Furthermore, although the above description assumes that the computer 30 executes the control program for the robot 40, including the chip mounting program 75b, the system is not limited to this, and the robot controller 50 may execute various control programs. In this case, the detection data from the force sensor 15 may not be transmitted to the computer 30 via the robot controller 50, but rather processed within the robot controller 50. Additionally, the robot controller 50 may be configured to store the dispensing program 75a, including the chip mounting program 75b, the chip coordinate data 75d, and the dispensing recipe file 75c in its storage unit. The computer 30 may also function as an operation input unit that issues commands for various tasks.

[0029] ***How ​​to attach the tip*** Figure 4 is a flowchart showing the process of attaching the chip. Figures 5 to 7 show one aspect of the chip attachment process. Here, the method for attaching the tip 8 to the pipette 7 will be explained, primarily using Figure 4, with other diagrams interspersed as needed. Each of the following steps is executed by the robot controller 50 controlling the robot 40 according to the tip attachment program 75b. The tip attachment program 75b is included in the dispensing program 75a, and the appropriate tip 8 is attached to the designated pipette 7 each time dispensing is performed. In other words, the method for attaching the tip 8 is a robot control method in which the control device 80 controls the operation of the robot 40 when attaching the tip 8, which is the workpiece, to the pipette 7, which is the tip device.

[0030] In step S10, the hand 5 grasps the designated pipette 7. For example, Figure 5 shows the hand 5 grasping pipette 7b. In Figure 5, tip 8b is shown with a dashed line. Tip 8b is a slender, pointed conical tube that gradually widens from the tip and has a slightly wider head 4 at the rear end. As shown in Figure 5, the tip 2 of pipette 7b is frustoconical, and tip 8b can be attached by inserting its upper base into the head 4 of tip 8b and pushing it in. Note that the shape of tip 8b is the same as tips 8a and 8c except for the size difference, so the sub-numbers will be omitted in the following explanation. The same applies to pipettes.

[0031] In step S11, the robot arm 220 is driven to move the pipette 7 onto the corresponding tip box 78b. Figure 6 shows the tip box 78b containing the tips 8 and the pipette 7 moved onto it. The tip box 78b is fitted with a guide plate 20 for aligning the tips 8. The guide plate 20 has nine holes 21 arranged in a matrix, into which the tips 8 are inserted. The diameter of the holes 21 is set to be smaller than the diameter of the head 4 of the tip 8 and larger than the part of the neck below the head 4. Therefore, the tip 8 has a gap G of play within the hole 21. Note that tips without heads may also be used. In other words, the object is the tip 8, the tip device is the pipette 7, and the tip 8 is housed in a tip box 78b that can accommodate multiple tips 8.

[0032] In step S12, the robot arm 220 is driven to move the pipette 7 onto the target tip 8 to be attached. The position of the target tip 8 is determined by referencing the reference position coordinates from the coordinate data 75d in the storage unit 35 of the computer 30. The reference position coordinates are design value coordinates, and the planar XY coordinates are the center coordinates of the hole 21 in the guide plate 20. The height coordinate Z of the tip 8 is the design height of the head 4 when the tip 8 is inserted into the guide plate 20. In a preferred example, as shown in Figure 6, the center of the tip 2 of the pipette 7 is moved to a starting position p1 which is a distance L0 from the upper surface 4a of the tip 8 in the reference position coordinates of the target tip 8. The distance L0 is, for example, 2 mm. In Figure 6, the line segment passing through the center of the hole 21 in the guide plate 20 and along the Z axis is defined as the center line 60. The line segment along the Z axis with the pipette 7 in an upright position is defined as the center line 62 of the pipette 7. The point passing through the center line 62 that serves as the operating reference for the pipette 7 is defined as the reference point 65. In Figure 6, the center line 62 coincides with the center line 60, and both the reference point 65 and the starting position p1 are located on the center line 60. The position of the pipette 7 when the center line 62 coincides with the center line 60 and the pipette is upright is called the first position.

[0033] In step S13, the tracking motion is performed using the detection data from the force sensor 15. First, as shown in Figure 6, the pipette 7 in the first position with its tip 2 at the starting position p1 is moved in the Z-minus direction, which is the first direction. In the preferred example, the distance L1 moved is, for example, 3 mm. The force sensor 15 detects the force and moment during the movement. Figure 7 shows one example of a successful attachment, where the tip 2 of the pipette 7 is inserted into the head 4 of the tip 8 by a distance L2. In the preferred example, the distance L2 is, for example, 1 mm.

[0034] Next, based on the values ​​detected by the force sensor 15, if the tip 2 of the pipette 7 comes into contact with the tip 8, the tip 2 of the pipette 7 performs a tracing motion relative to the tip 8. Tracing motion is the process of slightly moving the tip 2 of the pipette 7 in the opposite direction to the force and moment detected by the force sensor 15. Details of the tracing motion will be described later.

[0035] In step S14, it is determined whether the tip 2 of the pipette 7 has moved more than a predetermined distance in the Z-minus direction. The predetermined distance is, for example, distance L1. If it has moved more than the predetermined distance (step S14 / Yes), proceed to step S15. If it has not moved more than the predetermined distance (step S14 / No), record the coordinates and detection data at that position, and proceed to step S16. Alternatively, if there has been no movement more than the predetermined distance, proceed to step S16 after a predetermined time has elapsed. The predetermined time is, for example, approximately 5 seconds.

[0036] In step S15, the pipette 7 is moved in the Z-minus direction, and the tip 8 is attached to the tip 2. At this time, the force applied to the pipette 7 should be stronger than the force applied during the movement in the tracing motion. For example, the force applied should be 20N to 30N. In other words, if the pipette 7 has moved beyond a predetermined distance in the determination in step S14, the pipette 7 is moved in the Z-minus direction, and the tip 8 is attached.

[0037] In step S16, move pipette 7 in the Z-plus direction, separating tip 2 from tip 8. The distance moved should be, for example, to the same height as the starting position p1.

[0038] In step S17, the position of the tip 2 of pipette 7 is moved in a direction intersecting the Z direction to change the next starting position. The method for changing the starting position will be described later. In other words, the method for attaching the tip 8 includes: (1) moving the position of the pipette 7 as the tip device in the Z-minus direction as the first direction while in the first position; (2) if the pipette 7 comes into contact with the tip 8 based on the detection value of the force sensor 15, performing a tracking motion with the pipette 7 relative to the tip 8; (3) determining whether the pipette 7 has moved a predetermined distance or more in the Z-minus direction; and (4) if the determination is no, moving the pipette 7 in the Z-plus direction as the second direction opposite to the Z-minus direction, away from the tip 8, and repeating steps (1) to (4) again with respect to the tip 8.

[0039] ***If installation is successful*** Figure 8 is a graph showing the force sensor detection data when the chip is successfully attached, with the horizontal axis representing time (seconds) and the vertical axis representing force (N). Graph 91x shows the detected values ​​in the X direction, graph 91y shows the detected values ​​in the Y direction, and graph 91z shows the detected values ​​in the Z direction. In graph 91z, the detected value is approximately zero until about 1.4 seconds, from which a force in the Z-minus direction is applied, and from about 2.5 seconds a force of approximately -30N is applied. This indicates that because the detected value from force sensor 15 is approximately zero, it was determined in step S14 that movement had occurred beyond a predetermined distance, and the pushing operation in step S15 was performed. In other words, the section in graph 91z where the detected value is approximately zero until 1.4 seconds corresponds to the case where movement exceeded a predetermined distance in step S14, and the section from approximately 2.5 seconds onwards where a force of approximately 30N is applied corresponds to the pushing operation in step S15. Note that graphs 91x and 91y remain approximately zero and do not change.

[0040] Furthermore, if the tip 8 moves within the hole 21 due to the tracing motion, causing the tip 2 of the pipette 7 to move a predetermined distance, the graph will be approximately the same as that shown in Figure 8, and the attachment of the tip 8 will be successful.

[0041] ***In case of installation failure*** Figure 9 shows one example of a failed installation and corresponds to Figure 7. Figure 10 is a graph showing the force sensor detection data when the chip installation fails and corresponds to Figure 8. In Figure 9, the tip 8 is positioned in the X-minus direction within the hole 21, and during the tracing motion, the tip 2 of the pipette 7 contacts the X-plus side wall of the head 4 of the tip 8. Figure 9 shows a state where further movement is not possible even with the tracing motion, and the centerline 62 of the pipette 7 is tilted from the centerline 60. At this time, a force f1, which is a reaction force due to contact with the side wall, is acting on the reference point 65 of the pipette 7. Force f1 is the sum of the force and moment in the Z-plus and X-minus directions.

[0042] In Figure 10, graph 92x shows the detected values ​​in the X direction, graph 92y shows the detected values ​​in the Y direction, and graph 92z shows the detected values ​​in the Z direction. In graph 92z, the detected value is approximately zero until about 3 seconds, at which point a force is applied in the Z-minus direction, and from about 5 seconds onwards, a force of approximately -5N is applied. This indicates that the tip 2 of pipette 7 is stuck against the head 4 of tip 8 and cannot move, and cannot be moved even if a tracing motion is performed. Note that graphs 92x and 92y remain approximately zero and do not change. In this case, the coordinates and detection data at the position where movement is impossible are recorded, step S16 moves in the Z-plus direction away from chip 8, and step S17 moves the starting position.

[0043] ***Methods of changing the starting position*** Figure 11 shows how the starting position of the copy movement is changed, and is an XY coordinate diagram centered on the initial starting position p1. The following methods can be used to set the starting position for the copy motion during a retry. The first method involves moving the starting position to coordinate p11. The orientation of the pipette 7 is returned to the first orientation. Coordinate p11 is a position moved approximately 0.2 mm in the X-positive direction from the starting position p1. Note that the amount of movement is not limited to 0.2 mm and can be set appropriately according to the size of the tip 8. For example, in the case of tip 8b, it is preferable to set the amount of movement to 0.5 mm or less, taking into account the amount of play with the hole 21. In other words, in the repeated process, with the pipette 7 separated from the tip 8, the position of the tip 2 of the pipette 7 is moved in the X direction, which is a third direction intersecting the Z-minus direction, which is a first direction, and then the tracing operation of step S13 is performed. According to this, performing the second tracing operation from coordinate p11 increases the likelihood of successfully attaching the chip 8.

[0044] The second method involves moving the starting position to coordinate p12. The orientation of pipette 7 is returned to the first orientation. Coordinate p12 is the position moved approximately 0.3 mm in the negative X direction from the starting position p1, for example, as a predetermined distance. Coordinate p12 is the position moved by a predetermined distance in the direction in which a force (e.g., force f1) was applied, based on the detection data when the pipette became immobile during the previous tracing motion. In other words, the third direction is the direction in which the reference point 65 of pipette 7 changed due to the change in the orientation of tip 8 during the previous tracing motion. A change in posture during the tracing motion indicates a high probability that pipette 7 is in contact with the side wall of tip 8. In this case, inserting the pipette 7 into a position aligned with the direction of the posture change can increase the likelihood of successful tip attachment.

[0045] The third method involves moving the starting position to coordinate p13. The orientation of pipette 7 is returned to the first orientation. Coordinate p13 is a position moved approximately 0.2 mm in the negative X direction and approximately 0.2 mm in the positive Y direction from the starting position p1. Coordinate p13 is a position in a random direction intersecting the negative Z direction, which is the first direction. In other words, in the iterative process, with pipette 7 separated from tip 8, the position of the tip 2 of pipette 7 is moved in a random direction intersecting the negative Z direction, which is the first direction, and then the tracing operation of step S13 is performed. According to this method, by randomly changing the starting position, it becomes possible to attempt insertion at various positions, thereby increasing the likelihood of successful placement.

[0046] A fourth method is to start again from the starting position p1 without changing the starting position p1. The orientation of pipette 7 is returned to the first orientation. In other words, in the repeated process, with pipette 7 detached from tip 8, the tracing action of step S13 is performed without moving the starting position p1 of pipette 7. As mentioned above, since the chip 8 can move within the range of play in the hole 21 of the guide plate 20, the position of the chip 8 may change when the tracing motion is performed. In this case, if the robot tries again from the same starting position p1, it may be possible to successfully insert the chip 8, whose position has changed since the previous attempt. This allows for energy-saving re-insertion by minimizing the movement of the robot 40.

[0047] The fifth method involves setting the starting position to a coordinate obtained by changing only the Z coordinate of the coordinate at which the tip 2 of the pipette 7 hits the tip 8 and becomes immobile, as shown in Figure 9. The pipette 7 is returned to its first position. In other words, the starting position is set to a coordinate where only the Z coordinate is at the same height as the starting position p1 in the XY plane coordinates of the coordinate at which it became immobile, and the test is retried. As shown in Figure 9, the position at which the tip 2 of the pipette 7 hits the tip 8 and becomes immobile is set to p15', and the starting position p15 is set to a coordinate obtained by changing only the Z coordinate of p15' to +2mm. The starting position p15 is located approximately 0.1 mm away from the starting position p1 in the negative X direction. Here, the coordinate at which the tip 2 of the pipette 7 hits the tip 8 and becomes immobile is based on the position of the tool center point set on the robot 40. The tool center point is the reference position for controlling the robot 40. The coordinates of the reference position can be obtained by changing only the Z coordinate by +2mm from the position p15' where the tip 2 of pipette 7 hits the tip 8 and becomes immobile, and using that as the coordinate of the starting position p15. Since the chip 8 can move within the range of play in the hole 21 of the guide plate 20, the position of the chip 8 may change when a copying motion is performed. This method makes it possible to successfully insert the chip 8 into a position that has changed since the previous time.

[0048] In other words, the robot system 200 comprises a robot arm 220, a robot 40 having a pipette 7 as an end-effector and a force sensor 15 attached to the tip of the robot arm 220, and a control device 80 that controls the movement of the robot 40. The control device 80 causes the robot 40 to move the position of the pipette 7 in the Z-minus direction as a first direction when attaching a tip 8 as a workpiece to the pipette 7, and based on the value detected by the force sensor 15, if the pipette 7 comes into contact with the tip 8, the control device 80 causes the pipette 7 to perform a tracking motion with the tip 8, and determines whether the pipette 7 has moved more than a predetermined distance in the Z-minus direction. If the determination is no, the control device 80 causes the pipette 7 to move in the Z-plus direction as a second direction opposite to the Z-minus direction, and repeats this process until the pipette 7 has moved more than a predetermined distance in the determination.

[0049] As described above, the robot control method and robot system 200 of this embodiment provide the following advantages. A robot control method comprising a robot arm 220, a robot 40 having a pipette 7 as an end-effector and a force sensor 15 attached to the tip of the robot arm 220, and a control device 80 for controlling the movement of the robot 40, wherein the control device 80 controls the movement of the robot 40 when attaching a tip 8 as a work object to the pipette 7, the method includes: (1) moving the position of the pipette 7 as an end-effector in the Z-minus direction as a first direction in a first posture state; (2) if the pipette 7 comes into contact with the tip 8 based on the detection value of the force sensor 15, performing a tracking motion with the pipette 7 toward the tip 8; (3) determining whether the pipette 7 has moved a predetermined distance or more in the Z-minus direction; and (4) if the determination is no, moving the pipette 7 in the Z-plus direction as a second direction opposite to the Z-minus direction to move it away from the tip 8, and repeating (1) to (4) again toward the tip 8.

[0050] Since the object is not fixed, its position may change when the tracking motion is performed. In this case, if the insertion motion is performed again at the same insertion position as before, there is a possibility that insertion into the object, whose position has changed from the previous position, will be successful. For example, if the object is a tip 8 stored in a tip box 78b, the pipette 7 will move within the range of play in the hole 21 of the guide plate 20 as it makes contact through the tracking motion, changing its position. Therefore, even if the insertion position is the same as before, there is a possibility that insertion will be successful in the next insertion motion. Thus, the robot motion can be reduced to a minimum number of repetitions, and re-insertion can be performed efficiently with energy savings. Therefore, it is possible to provide a robot control method that can reliably attach an object even if the object is not fixed in place.

[0051] Furthermore, in the repeated process, with the pipette 7 separated from the tip 8, the position of the tip 2 of the pipette 7 is moved in the X direction, which is a third direction intersecting the Z-minus direction, which is a first direction, and then the tracing operation of step S13 is performed. According to this, performing the second tracing motion from coordinate p11, which is moved in the X direction, increases the likelihood of successfully attaching the chip 8.

[0052] Furthermore, the third direction is the direction in which the reference position of the pipette 7 changed due to the change in the orientation of the tip 8 during the preceding tracing motion. A change in posture during the tracing motion indicates a high probability that pipette 7 is in contact with the side wall of tip 8. In this case, inserting the pipette 7 into a position aligned with the direction of the posture change can increase the likelihood of successful tip attachment.

[0053] Furthermore, in the repeated process, with the pipette 7 separated from the tip 8, the position of the tip 2 of the pipette 7 is moved in a random direction intersecting the Z-minus direction as the first direction, and then the tracing operation of step S13 is performed. According to this method, by randomly changing the starting position, it becomes possible to attempt insertion at various positions, thereby increasing the likelihood of successful placement of chip 8.

[0054] Furthermore, the repeated process includes performing the tracing action of step S13 with the pipette 7 detached from the tip 8 and without moving the starting position p1 of the pipette 7. Since the chip 8 can move within the range of play in the hole 21 of the guide plate 20, the position of the chip 8 may change when the tracing motion is performed. In this case, if the robot tries again from the same starting position p1, it may be possible to successfully insert the chip 8, whose position has changed since the previous attempt. This allows for energy-saving re-insertion by minimizing the movement of the robot 40.

[0055] Furthermore, if the pipette 7 has moved beyond a predetermined distance during the determination in step S14, the pipette 7 is moved in the Z-minus direction and the tip 8 is attached. According to this, the tip 8 can be securely attached to the tip 2 of the pipette 7.

[0056] Furthermore, the object is a tip 8, the tip device is a pipette 7, and the tip 8 is housed in a tip box 78b that can accommodate multiple tips 8. According to this, it is possible to provide a robot control method that ensures the chip 8 is securely attached, even if the chip 8 is not fixed in place.

[0057] The robot system 200 comprises a robot arm 220, a robot 40 having a pipette 7 as an end-effector and a force sensor 15 attached to the tip of the robot arm 220, and a control device 80 that controls the movement of the robot 40. The control device 80 controls the robot 40 to move the position of the pipette 7 in the Z-minus direction, which is the first direction, when the robot 40 attaches a tip 8 as a workpiece to the pipette 7, and based on the value detected by the force sensor 15, if the pipette 7 comes into contact with the tip 8, the control device 80 controls whether the pipette 7 has moved more than a predetermined distance in the Z-minus direction, and if the determination is no, the control device 80 controls the robot 40 to move the pipette 7 in the Z-plus direction, which is the second direction opposite to the Z-minus direction, and repeats this process until the pipette 7 has moved more than a predetermined distance in the determination.

[0058] For example, if the target object is a tip 8 stored in a tip box in the tip holder 78, the pipette 7 will move within the range of play in the hole 21 of the guide plate 20 as it makes contact through its tracking motion, changing its position. Therefore, even if the insertion position is the same as the previous time, there is a possibility that the next insertion operation will be successful. Thus, the robot operation can be reduced to a minimum number of repetitive movements, enabling energy-saving and efficient re-insertion. Therefore, it is possible to provide a robot system 200 that can reliably attach an object even if the object is not fixed in place. [Explanation of symbols]

[0059] 1...Reagent bottle, 1a...Reagent bottle, 1b...Reagent bottle, 1f...Reagent bottle, 2...Tip, 3...Container, 4...Head, 4a...Top, 5...Hand, 5a...Hand, 5b...Hand, 7...Pipette, 7a...Pipette, 7b...Pipette, 7c...Pipette, 8...Tip, 8a...Tip, 8b...Tip, 8c...Tip, 10...Nozzle, 15...Force sensor, 20...Guide plate, 21...Hole, 30...Computer, 31...Display unit, 32...Operation unit, 33...IF unit, 34...Control unit, 35...Memory unit, 40...Robot, 50...Robot controller, 60...Centerline, 62...Centerline, 65...Reference point, 71...Reagent storage area, 72...Reagent table, 73...Container storage area, 74...Lid opening / closing unit, 75...Container table, 75a...Dispensing pipe Program, 75b...Tip attachment program, 75c...Dispensing recipe file, 75d...Coordinate data, 76...Lid opening / closing unit, 77...Pipette holder, 78...Tip holder, 78a...Tip box, 78b...Tip box, 78c...Tip box, 79...Electronic balance, 80...Control device, 91x...Graph, 91y...Graph, 91z...Graph, 92x...Graph, 92y...Graph, 92z...Graph, 100...Dispensing device, 200...Robot system, 210...Base, 220...Robot arm, 221,222,223,224,225,226...Arm, f1...Force, J1...Joint, J2...Joint, L0...Distance, L1...Distance, L2...Distance, p1...Starting position, p11...Coordinates, p12...Coordinates, p13...Coordinates, p15...Starting position.

Claims

1. A robot arm, and a robot having an end-effector and force sensor attached to the tip of the robot arm, The system includes a control device for controlling the operation of the robot, A robot control method in which the robot's movements are controlled by the control device when attaching an object to be worked on to the aforementioned advanced device, (1) Moving the position of the tip device in the first position in the first direction, (2) When the tip device comes into contact with the object based on the value detected by the force sensor, the tip device performs a tracing motion with respect to the object. (3) Determining whether the tip device has moved a predetermined distance or more in the first direction, (4) If the determination is negative, move the tip device in a second direction opposite to the first direction and move it away from the object, This includes repeating steps (1) to (4) above on the object, Robot control methods.

2. In the aforementioned iterative process, The procedure described in (4) above involves moving the tip device away from the object, then moving the position of the tip device in a third direction intersecting the first direction, and then performing (1), A method for controlling a robot according to claim 1.

3. The third direction is the direction in which the reference position of the tip device changes due to the change in the posture of the object in the preceding tracing motion. The robot control method according to claim 2.

4. In the aforementioned iterative process, The procedure described in (4) above involves moving the tip device away from the object, then moving the position of the tip device in a random direction intersecting the first direction, and then performing (1), A method for controlling a robot according to claim 1.

5. In the aforementioned iterative process, The above (4) includes performing (1) while the tip device is separated from the object, without moving the position of the tip device, A method for controlling a robot according to claim 1.

6. In the determination described in (4) above, if the tip device moves beyond a predetermined distance, the tip device is moved in the same direction as before, and the object is attached. A method for controlling a robot according to claim 1.

7. The aforementioned object is a chip, The aforementioned tip device is a pipette, The chip is housed in a chip box capable of arranging multiple chips. A method for controlling a robot according to any one of claims 1 to 6.

8. A robot arm, and a robot having an end-effector and force sensor attached to the tip of the robot arm, The system includes a control device for controlling the operation of the robot, The control device is When the robot attaches the work object to the end device, In the first posture, the position of the tip device is moved in the first direction. Based on the force sensor's detection value, if the tip device comes into contact with the object, the tip device performs a tracing motion relative to the object. It is determined whether the tip device has moved a predetermined distance or more in the first direction. If the above determination is negative, the tip device is moved in a second direction opposite to the first direction, and this process is repeated until the tip device moves a predetermined distance or more in the determination. Robot system.

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