Industrial robot and method for controlling the same

Abstract

This invention provides an industrial robot and its control method. In a robot with a multi-stage lifting section, vibrations generated by the movement of the lifting section can be suppressed, thus achieving correct movement. In a robot comprising a robot body (10) and a robot control device (50) for controlling the robot body (10), the robot body (10) includes: a base (20); an arm assembly (40); and a lifting section that allows the arm assembly (40) to move relative to the base (20). The lifting section has a structure in which multiple lifting components (21-23), each driven by a motor (31-33) and capable of moving vertically, are connected in series. The robot control device (50) independently controls each stage of the motors (31-33) of the lifting section of the robot body (10).

Description

Technical Field

[0001] This invention relates to an industrial robot (hereinafter referred to as a robot) used in the conveying of workpieces and the like, and its control method. Background Technology

[0002] Industrial robots for transporting workpieces such as semiconductor wafers or glass substrates typically consist of a base, a hand holding the workpiece, an arm assembly with the hand mounted at its front end, and a lifting unit connected to the base that allows the arm assembly to move vertically. The arm assembly is configured to connect multiple arms, each of which can rotate in a horizontal plane. The lifting unit, for example, includes a columnar or cylindrical lifting member extending vertically, on which the arm assembly is mounted. By moving the lifting member vertically relative to the base, the arm assembly also moves vertically, allowing the height of the hand to be arbitrarily varied. In such robots, to sufficiently increase the movable distance in the vertical direction compared to the total height of the robot when the lifting unit is in its lowest position, the lifting unit is sometimes configured as a multi-stage structure, allowing the arm assembly to move significantly vertically by extending and retracting the lifting unit. For example, Patent Document 1 discloses a robot having a first lifting member that moves vertically relative to a base, and a second lifting member capable of moving vertically relative to the first lifting member. The second lifting member serves as an arm support, and the arm assembly is mounted on the second lifting member. The robot described in Patent Document 1 has a two-stage lifting mechanism, but it is also possible to consider a multi-stage lifting mechanism with three or more stages.

[0003] In robots, the lifting mechanism only performs vertical movement. Therefore, even when the lifting mechanism is configured as a multi-stage structure, it is sometimes constructed with only one motor driving the lifting mechanism, using a chain to drive each stage of the lifting member. In this case, if the first-stage lifting member moves a distance h relative to the base, the second-stage lifting member also moves a distance h relative to the first-stage lifting member, and each stage of the lifting member moves simultaneously and relatively by the same amount. Alternatively, sometimes different motors are used to drive each of the multiple lifting members constituting the lifting mechanism. In this case, multiple motors are also driven simultaneously, and each stage of the lifting member moves simultaneously. Furthermore, in the robot's coordinate system, the vertical direction is often referred to as the Z-axis, so the movement of the lifting mechanism is sometimes called movement in the Z-axis direction, and the motor driving the lifting mechanism is called a Z-axis motor.

[0004] [Existing technical documents]

[0005] [Patent Literature]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 2012-40650 Summary of the Invention

[0007] [The problem the invention aims to solve]

[0008] In robots, when the lifting mechanism that moves the arm assembly vertically between the base and the arm assembly is configured as a multi-stage structure, vibration is easily generated when the lifting mechanism is activated. In robots used for transporting workpieces, where Z-axis movement (i.e., movement of the lifting mechanism) is required for workpiece handover, this vibration can prevent proper handover or waste time waiting for vibration to decay. Even when configured with only one motor driving the lifting mechanism and a chain driving each stage of the lifting components, the positional relationship of the motor or chain can cause an imbalance in the drive source positions of each stage of the lifting mechanism within the lifting unit, sometimes inducing vibration.

[0009] The purpose of this invention is to provide a robot and its control method, wherein the robot has a multi-stage lifting mechanism that can suppress vibrations generated by the movement of the lifting mechanism and achieve correct movements.

[0010] [Technical means to solve the problem]

[0011] One embodiment of the robot includes: a robot body; and a robot control device that controls the robot body. The robot body includes: a base; an arm assembly; and a multi-stage lifting mechanism that allows the arm assembly to move relative to the base. Let N be an integer greater than or equal to 2, and i be an integer greater than or equal to 2 but less than N. The lifting mechanism has a structure that connects N lifting members, each capable of moving vertically, in series. Each lifting member includes a motor that moves the lifting member vertically. A first-stage lifting member is mounted on the base, an i-th-stage lifting member is mounted on the (i-1)-th-stage lifting member, and the arm assembly is mounted on the N-th-stage lifting member. The robot control device independently controls each stage of the motor.

[0012] One embodiment of the control method is a robot control method, the robot including: a base; an arm assembly; a hand mounted on the front end of the arm assembly; and a multi-stage lifting unit that allows the arm assembly to rise and fall relative to the base, where N is an integer greater than or equal to 2, and i is an integer greater than or equal to 2 and less than N. The lifting unit has a structure in which N lifting members, each capable of moving in a vertical direction, are connected in series, and each lifting member includes a motor that moves the lifting member in a vertical direction. A first-stage lifting member is mounted on the base, an i-th-stage lifting member is mounted on an (i-1)-th-stage lifting member, and the arm assembly is mounted on an N-th-stage lifting member. In the robot control method, for the action that the robot is to perform, the method selects, depending on the content, whether to run the motors simultaneously to generate the lifting amount of each stage in all lifting members, or to run the motors to generate the lifting amount of each stage only in a subset of stages.

[0013] [The effects of the invention]

[0014] According to the present invention, in a robot with a multi-stage lifting section, vibrations generated by the movement of the lifting section can be suppressed, and correct movements can be achieved. Attached Figure Description

[0015] Figure 1 This is a diagram showing the main body of a robot in one embodiment of a robot. Figure 1 (a) is a plan view. Figure 1 (b) is a plan view with the hand and arm components removed. Figure 1 (c) is a front view of the arm assembly in its lowest position. Figure 1 (d) is a front view of the arm assembly in the state where it is moved upward to the maximum extent.

[0016] Figure 2 It is a block diagram representing the circuit structure of a robot.

[0017] Figure 3 This is a flowchart illustrating the process of driving the Z-axis based on instructions.

[0018] Explanation of icon numbers

[0019] 10: Robot Body

[0020] 20: Abutment

[0021] 21: Lifting component / First lifting component

[0022] 22: Lifting component / Second lifting component

[0023] 23: Lifting component / Third lifting component

[0024] 26, 27, 28: Ball screws

[0025] 31, 32, 33, 34, 35, 36, 37: Motor

[0026] 40: Arm assembly

[0027] 41: Arm / First Arm

[0028] 42: Arm / Second Arm

[0029] 43: Arm / Third Arm

[0030] 45: Hands

[0031] 50: Robot control device

[0032] 51: Control and operational circuit

[0033] 61, 62, 63, 64, 65, 66, 67: Servo drivers

[0034] 101, 102, 103, 104: Steps

[0035] L1, L2, L3, L4, Z, Z1, Z2, Z3: Axis Detailed Implementation

[0036] Next, preferred embodiments of the present invention will be described with reference to the accompanying drawings. Figure 1 This illustrates a robot body 10 in a robot according to one embodiment. The robot body 10 and the robot control device 50 that controls the robot body 10 (see reference 50) Figure 3 These can be combined to form a robot in one implementation method.

[0037] The robot of this embodiment is configured as a horizontal, multi-jointed transport robot for transporting plate-shaped workpieces such as semiconductor wafers or glass substrates while maintaining their horizontal position. The robot body 10 includes: a base 20; a lifting unit including a first lifting member 21 to a third lifting member 23; an arm assembly 40 connected to the lifting unit; and a hand 45 disposed at the front end of the arm assembly 40 and carrying the workpiece to be transported. The lifting unit is provided to enable the arm assembly 40 to move in the vertical direction (Z-axis direction), i.e., to rise and fall. Figure 1 (c) indicates the state in which the arm assembly 40 is in its lowest position due to the movement of the lifting unit. Figure 1 (d) indicates the state in which the arm assembly is in the uppermost position.

[0038] Lifting components 21 to 23 are all four-cornered cylindrical components extending along the vertical direction, such as... Figure 1 As shown in (c), in the most retracted state of the lifting section, the first lifting member 21 is stored within the base 20, the second lifting member 22 is stored within the first lifting member 21, and the third lifting member 23 is stored inside the second lifting member 22. The first lifting member 21 is connected to a ball screw 26 driven by a motor 31 disposed within the base 20, and can move vertically by the motor 31 driving the ball screw 26, protruding from or being pulled into the upper end of the base 20. Figure 1As indicated by the arrow in (d), this movement of the first lifting member 21 is referred to as the movement of the Z1 axis in the robot. Similarly, the second lifting member 22 is connected to a ball screw 27 driven by a motor 32 located within the first lifting member 21, and can move vertically by the motor 32 driving the ball screw 27, protruding from or being pulled into the upper end of the first lifting member 21. This movement of the second lifting member 22 is referred to as the movement of the Z2 axis. The third lifting member 23 is connected to a ball screw 28 driven by a motor 33 located within the second lifting member 22, and can move vertically by the motor 33 driving the ball screw 28, protruding from or being pulled into the upper end of the second lifting member 22. This movement of the third lifting member 23 is referred to as the movement of the Z3 axis.

[0039] The arm assembly 40 is formed by sequentially connecting the first arm 41, the second arm 42, and the third arm 43. One end of the first arm 41 is connected to the upper end of the third lifting member 23, and this connection position is set as the L1 axis. The first arm 41 can rotate around the L1 axis in the horizontal plane. A motor 34 is provided to drive the rotation of the first arm 41 around the L1 axis (see reference). Figure 2 The other end of the first arm 41 is positioned at axis L2, and one end of the second arm 42 is connected to the other end of the first arm 41 at axis L2, so that the second arm 42 can rotate around axis L2 in the horizontal plane. A motor 35 is provided to drive the rotation of the second arm 42 around axis L2 (see reference). Figure 2 The other end of the second arm 42 is positioned at axis L3, and one end of the third arm 43 is connected to the other end of the second arm 42 at axis L3, so that the third arm 43 can rotate around axis L3 in the horizontal plane. A motor 36 is provided to drive the rotation of the third arm 43 around axis L3 (see reference). Figure 2 The hand 45 is forked to hold the plate-shaped workpiece horizontally. The other end of the third arm 43 is positioned at the L4 axis, and the base of the hand 45 is connected to the other end of the third arm 43 at the L4 axis, allowing the hand 45 to rotate horizontally around the L4 axis. A motor 37 is provided to drive the rotation of the hand 45 around the L4 axis (see reference). Figure 2 Axis L1 to L4 are all axes that extend in the vertical direction.

[0040] The robot control device 50 includes: a control processing circuit 51, which generates position commands (or speed commands) for each axis as internal commands based on externally input instructions (external commands); and servo drives 61 to 67, respectively configured to correspond to motors 31 to 37 of the robot body 10. The servo drives 61 to 67 perform servo control on their respective motors 31 to 37 based on the internal commands generated by the control processing circuit 51. Each motor 31 to 37 is equipped with an encoder, and the motor position detected by the encoder is fed back to the corresponding servo drive 61 to 67.

[0041] In the robot of this embodiment, motors 31 to 33, which drive the first lifting member 21 to the third lifting member 23, are independently controlled within the robot body 10. When the control calculation circuit 51 receives an external command that moves the arm assembly 40 in the height direction and generates internal commands for each axis in the robot body 10 based on the external command, the control calculation circuit 51 may not necessarily need to generate internal commands for simultaneous movement of the axes related to the lifting members, namely the Z1, Z2, and Z3 axes. For example, the control calculation circuit 51 generates internal commands related to motors 31 to 33 and outputs them to servo drivers 61 to servo drivers 63, such that only the first lifting member 21 is raised and lowered relative to the base 20 by driving only the motor 31 on the Z1 axis of motors 31 to 33, while the second and third lifting members 22 and 23 do not move relative to the first lifting member 21. In other words, the control calculation circuit 51 can generate internal commands to rotate one or both of the three motors 31 to 33 when raising and lowering the arm assembly 40. Of course, if all three motors 31 to 33 are driven and rotated at the same time, causing the first lifting component 21 to the third lifting component 23 to move in the same direction at the same time, the arm assembly 40 will lift and lower at the highest speed, and the height position of the workpiece placed on the hand 45 can also be changed at the highest speed.

[0042] Furthermore, the robot for transporting workpieces such as semiconductor wafers or glass substrates is used to move workpieces between processing devices that perform various processes on the workpieces, such as vapor deposition or cleaning. Each processing device is provided with a loading / unloading outlet for receiving workpieces. The robot transfers workpieces by having its hand 45 enter the interior of the processing device through the loading / unloading outlet. When the hand 45 has moved to a position in front of the loading / unloading outlet (called the standby position), and a workpiece is to be placed on the hand 45 from the processing device, the hand 45 is inserted below the workpiece, which is held horizontally in a clamp or the like, inside the loading / unloading outlet. Then, the hand 45 is raised a small distance, approximately a few millimeters to a few centimeters, thereby transferring the workpiece from the clamp to the hand 45. Then, the hand 45, holding the workpiece, is pulled outward from the loading / unloading outlet, returning the hand 45 to its original standby position. The action of moving the hand 45 from the standby position, placing the workpiece on the hand 45, and returning the workpiece to the standby position is called a get action. Conversely, when unloading a workpiece from the hand 45 into the processing device, assuming the hand 45 has already moved to the standby position, the hand 45, with the workpiece on it, enters the inlet / outlet of the processing device so that the hand 45 is above the fixture on the processing device side. Then, by lowering the hand 45, for example, by a few mm to a few cm, the workpiece is transferred from the hand 45 to the fixture. Then, the now unloaded hand 45 is pulled out from the inlet / outlet, returning the hand 45 to its original standby position. The action of moving the hand 45 with the workpiece on it from the standby position, placing the workpiece on the fixture, and returning the hand 45 to the standby position is called a put action. In the actions of acquiring and releasing, the actions of moving the hand 45 into the loading / unloading outlet and pulling the hand 45 out of the loading / unloading outlet are achieved by controlling the rotation of the arms 41 to 43 around the L1 axis to the L3 axis and the rotation of the hand 45 around the L4 axis by the control calculation circuit 51. The raising and lowering of the hand 45 are achieved by controlling the lifting part by the control calculation circuit 51.

[0043] During the picking action, it is required to correctly position and mount the workpiece on the hand 45, and during the lowering action, it is required to correctly position and unload the workpiece onto the fixture. When the hand 45 vibrates due to the lifting action, it is difficult to correctly position the workpiece. Therefore, in this embodiment, when the hand 45 is raised and lowered to perform the picking and lowering actions inside the loading / unloading outlet of the processing device, the motors 31 to 37 on the Z1 to Z3 axes are controlled so that only the uppermost lifting member, namely the third lifting member 23, moves, and the remaining lifting members, namely the first lifting member 21 and the second lifting member 22, do not move. Considering the mass borne by each of the lifting members 21 to 23, the first lifting member 21 bears the mass from the second lifting member 22 to the workpiece on the hand 45. In contrast, the third lifting member 23 bears only the mass of the arm assembly 40, the hand 45, and the workpiece on the hand 45, and the third lifting member 23 bears the least mass. As described above, the lifting distance during the acquisition or placement actions is small, and is sufficient to handle even if only one lifting member is activated. Therefore, when the lifting part is activated to raise or lower the hand 45, by moving only the third lifting member 23, the vibration generated in the hand 45 can be reduced, and the positioning accuracy of the workpiece can be improved.

[0044] Figure 3This is a flowchart illustrating the control using only the third lifting member 23 when performing the acquisition or placement actions, showing the processing of the control calculation circuit 51 when controlling the lifting unit. In the robot control device 50, the control calculation circuit 51 interprets external commands and generates internal commands for each axis. Therefore, when an external command is input, in step 101, the control calculation circuit 51 determines whether the external command includes a command that changes the height position of the hand 45, i.e., a command related to the Z-axis. If the command is not related to the Z-axis, the control calculation circuit 51 terminates the control related to the lifting unit. On the other hand, when the external command is a command related to the Z-axis, in step 102, the control calculation circuit 51 determines whether it is a command under a specific condition. Here, commands under specific conditions include at least commands for acquisition and placement actions. Since the lifting distance of the hand 45 in the acquisition or placement actions is short and at most a few centimeters, for example, a threshold can be set to 10cm, and commands that cause the lifting unit to move in a manner where the lifting distance of the hand 45 is below the threshold can be determined as commands under specific conditions. If the instruction is determined to be a specific condition, the control circuit 51 controls motors 31 to 33 in step 103, so that only the uppermost lifting member (the third lifting member 23 of the Z3 axis in this example) moves with respect to the Z-axis, while the other lifting members (lifting members 21 and 22 of the Z1 and Z2 axes in this example) remain in their original positions. Then, the control related to the lifting section ends. Conversely, if the instruction is determined not to be a specific condition, the control circuit 51 controls motors 31 to 33 in step 104, so that all lifting members of the Z-axis (lifting members 21 to 23 in this case) move simultaneously. Then, the control related to the lifting section ends.

[0045] Consider the scenario where a robot is used for workpiece transfer between two different processing units. The height positions of the inlet / outlet points differ significantly between the outgoing and incoming processing units, necessitating a change in the hand height (45°) between the standby positions in the outgoing and incoming processing units. If this situation arises, the robot's operation... Figure 3 According to the described process, the lifting motion of the hand 45 between the standby positions on the take-out side and the take-in side can be performed at high speed using all lifting components 21 to 23. Therefore, even when performing... Figure 3 The processing shown does not increase the time required for workpiece transport. Therefore, the processing described here can improve the positioning accuracy of both the placement and acquisition actions without extending the workpiece transport time.

[0046] In the robot of this embodiment described above, the lifting members 21 to 23 constituting the lifting section are driven independently by motors 31 and 33 respectively. Depending on the situation, it is possible to select whether to move the lifting members 21 to 23 simultaneously, or to move one or both of them. This allows for the suppression of vibrations caused by the movement of the lifting section, thus enabling accurate robot movements. In particular, it improves the positioning accuracy of the workpiece during the lowering and acquiring actions. Furthermore, by allowing the lifting members 21 to 23 to be moved individually, interference between the robot and other objects during its movements is more easily avoided. Since the lifting members 21 to 23 are driven by motors 31 and 33 respectively via ball screws 26 and 28, the drive sources for the lifting members 21 to 23 can be evenly distributed within the lifting section, thereby suppressing vibrations induced by imbalances in their distribution.

[0047] In the above description, the lifting unit is described as a three-stage structure including lifting members 21 to 23. However, regardless of whether the lifting unit has a two-stage or four-stage structure, by configuring it so that each stage of the lifting member is driven independently by a motor, the same effect as the structure in this embodiment can be obtained. That is, in the robot that achieves the same effect as the structure in this embodiment, in the robot body, N is set to be an integer of 2 or more, i is an integer of 2 or more and less than N, the lifting unit has a structure in which N lifting members, each capable of moving in the vertical direction, are connected in series, and each lifting member includes a motor that moves the lifting member in the vertical direction. The first-stage lifting member is mounted on the base, the i-th-stage lifting member is mounted on the (i-1)-th-stage lifting member, and the arm assembly is mounted on the N-th-stage lifting member. Furthermore, the robot control device independently controls each stage of the motor.

[0048] The above describes one example of a structure for implementing the present invention, but the technology can be implemented using the following structures.

[0049] [1] A robot includes: a robot body; and a robot control device for controlling the robot body, wherein the robot,

[0050] The robot body includes: a base; an arm assembly; and a multi-stage lifting mechanism that allows the arm assembly to move up and down relative to the base.

[0051] Let N be an integer greater than or equal to 2, and i be an integer greater than or equal to 2 but less than or equal to N. The lifting unit has a structure in which N lifting components, each capable of moving in the vertical direction, are connected in series. Each lifting component includes a motor for moving the lifting component in the vertical direction.

[0052] The first-stage lifting component is mounted on the base platform, the i-th-stage lifting component is mounted on the (i-1)-th-stage lifting component, and the arm assembly is mounted on the N-th-stage lifting component.

[0053] The robot control device independently controls each stage of the motors.

[0054] According to the structure in [1], in a robot with a multi-level lifting section, the lifting member that is less likely to cause vibration can be selectively operated from among the lifting members set in the multi-level structure, which can suppress the vibration generated by the operation of the lifting section and achieve correct operation. In addition, it is easier to avoid interference between the robot and other objects that accompany the robot's operation.

[0055] [2] According to the robot described in [1], when the robot control device controls the robot body according to the input instructions, it selects, according to the content of the instructions, whether to make the motor run simultaneously to generate the lifting amount of each stage in all the lifting components, or to make the motor run to generate the lifting amount of each stage only in a portion of the lifting components.

[0056] Here, the so-called lifting amount per level, when the lifting component is the first-level lifting component, refers to the relative lifting amount generated between the base and the first-level lifting component; when the lifting component is the i-th level lifting component, it refers to the relative lifting amount generated between the (i-1)-th level lifting component and the i-th level lifting component. The so-called lifting amount per level, if it is the first-level lifting component, means that there is a relative lifting movement between it and the base; if it is the i-th level lifting component, it means that there is a relative lifting movement between it and the (i-1)-th level lifting component. According to the structure of [2], when the vibration of the lifting part can be ignored, all lifting components can be used to perform lifting actions, thus preventing the time required for the robot to move from becoming longer.

[0057] [3] According to the robot described in [2], wherein when the instruction is a specific instruction, the robot control device controls the motor to produce the lifting amount of each stage only in the Nth stage lifting member.

[0058] [4] According to the robot described in [3], the specific instruction is an instruction to make the lifting part perform a lifting action, and the lifting amount of the lifting part as a whole is below a predetermined threshold.

[0059] According to the structure in [3], by setting the instructions for the robot to perform actions that are easily affected by vibration as specific instructions, and by inputting such specific instructions to move only the top-level lifting component, the mass of the part of the robot that moves through the lifting action can be minimized, and the generation of vibration can be suppressed more effectively. Since such specific instructions are usually related to lifting actions with small lifting amounts as a whole lifting part, the structure in [4] is adopted, and it is determined whether it is a specific action only by comparing with a threshold, thereby reducing the computational processing required for control.

[0060] [5] The robot according to [3] or [4], wherein the robot is a transport robot including a hand for carrying a workpiece and for transporting the workpiece.

[0061] The arm assembly is constructed by connecting multiple arms in a manner that allows each arm to rotate in the horizontal plane.

[0062] The hand is connected to the arm at the front end of the arm assembly in a manner that allows it to hold a workpiece and rotate in the horizontal plane.

[0063] [6] According to the robot of [5], the specific instruction includes at least one of an instruction to perform a lowering action of unloading the workpiece by lowering the hand on which the workpiece is mounted, and an instruction to perform an acquisition action of mounting the workpiece on the hand by raising the unloaded hand.

[0064] Transport robots, especially horizontal articulated robots used for transporting workpieces, are robots for which it is desirable to reduce the impact of vibration during workpiece positioning. By adopting the structure of [5], the impact of vibration accompanying the movement of the lifting part in the transport robot can be reduced. In addition, by adopting the structure of [6], the positioning accuracy of the workpiece during the lowering and picking movements in the transport robot can be improved.

[0065] [7] A control method is a robot control method, the robot comprising: a base; an arm assembly; a hand mounted on the front end of the arm assembly; and a multi-stage lifting unit for raising and lowering the arm assembly relative to the base, wherein N is an integer greater than or equal to 2, and i is an integer greater than or equal to 2 and less than N, the lifting unit having a structure for connecting N lifting components that are each capable of moving in a vertical direction in series, and each lifting component including a motor for moving the lifting component in a vertical direction, the first stage lifting component being mounted on the base, the i-th stage lifting component being mounted on the (i-1)-th stage lifting component, and the arm assembly being mounted on the N-th stage lifting component, in the robot control method

[0066] In the action that the robot is to perform, depending on the content, the choice is to run the motors simultaneously to produce the lifting amount per stage in all of the lifting components, or to run the motors to produce the lifting amount per stage only in a subset of stages.

[0067] According to the structure of [7], in a robot with a multi-level lifting unit, when performing an action in the robot that is easily affected by vibration, the lifting member that is not easily the cause of vibration can be selectively operated from the lifting members set in the multi-level structure. When the influence of vibration can be ignored, all lifting members can be used to perform the lifting action. Therefore, the vibration generated by the action of the lifting unit can be suppressed, the correct action can be achieved, and the time required for the robot to move can be prevented from becoming longer.

[0068] [8] According to the control method described in [7], when the instruction given for controlling the robot is a specific instruction, the motor is controlled to produce the lifting amount of each stage only in the Nth stage lifting member.

[0069] [9] According to the control method described in [8], the specific instruction is an instruction to make the lifting part perform a lifting action, and is an instruction that the lifting amount of the lifting part as a whole is below a predetermined threshold.

[0070]

[10] According to the control method described in [8] or [9], wherein, when the robot is a transport robot including a hand for carrying a workpiece and for transporting the workpiece, the arm assembly is configured to connect multiple arms in such a way that each arm can rotate in a horizontal plane, and the hand is connected to the arm at the front end of the arm assembly in such a way that it can carry a workpiece and can rotate in a horizontal plane, the specific instruction includes at least one of an instruction to perform a lowering action of unloading the workpiece by lowering the hand carrying the workpiece, and an instruction to perform an acquisition action of loading the workpiece onto the hand by raising the unloaded hand.

[0071] According to the structure of [8], by setting the instructions for the robot to perform actions that are easily affected by vibration as specific instructions, and by inputting such specific instructions to move only the uppermost lifting component, the mass of the part of the robot that moves through the lifting action can be minimized, and the generation of vibration can be suppressed more effectively. Since such specific instructions are usually related to lifting actions with small lifting amounts as a whole lifting part, the structure of [9] is adopted, and it is determined whether it is a specific action only by comparing with a threshold, thereby reducing the computational processing used for control. According to the structure of

[10] , the positioning accuracy of the workpiece during the lowering action and the acquisition action in the robot used for transport can be improved.

Claims

1. A robot, comprising: Robot body; and a robot control device to control the robot body, wherein the robot, The robot body includes: a base; an arm assembly; And a multi-stage lifting mechanism that allows the arm assembly to move up and down relative to the base. Let N be an integer greater than or equal to 2, and i be an integer greater than or equal to 2 but less than or equal to N. The lifting unit has a structure in which N lifting components, each capable of moving in the vertical direction, are connected in series. Each lifting component includes a motor for moving the lifting component in the vertical direction. The first-stage lifting component is mounted on the base platform, the i-th-stage lifting component is mounted on the (i-1)-th-stage lifting component, and the arm assembly is mounted on the N-th-stage lifting component. The robot control device independently controls each stage of the motors.

2. The robot according to claim 1, wherein, When the robot control device controls the robot body according to the input instructions, it selects, based on the content of the instructions, whether to make the motors run simultaneously to generate the lifting amount of each stage in all the lifting components, or to make the motors run to generate the lifting amount of each stage only in a portion of the lifting components.

3. The robot according to claim 2, wherein, When the instruction is a specific instruction, the robot control device controls the motor to produce the lifting amount of each stage only in the Nth stage lifting component.

4. The robot according to claim 3, wherein, The specific instruction is an instruction to cause the lifting unit to perform a lifting action, and the lifting amount of the lifting unit as a whole is below a predetermined threshold.

5. The robot according to claim 3 or 4, wherein, The robot is a transport robot that includes a hand for carrying workpieces and for transporting the workpieces. The arm assembly is constructed by connecting multiple arms in a manner that allows each arm to rotate in the horizontal plane. The hand is connected to the arm at the front end of the arm assembly in a manner that allows it to hold a workpiece and rotate in the horizontal plane.

6. The robot according to claim 5, wherein, The specific instruction includes at least one of the following: an instruction to perform a lowering action by causing the hand carrying the workpiece to lower, and an instruction to perform a picking action by causing the unloaded hand to raise, and placing the workpiece on the hand.

7. A control method, which is a robot control method, the robot comprising: abutment; arm assembly; The hand is mounted on the front end of the arm assembly; The robot control method includes a multi-stage lifting mechanism that allows the arm assembly to move relative to the base. N is an integer greater than or equal to 2, and i is an integer greater than or equal to 2 and less than N. The lifting mechanism has a structure that connects N lifting members, each capable of moving vertically, in series. Each lifting member includes a motor for moving vertically. The first-stage lifting member is mounted on the base, the i-th-stage lifting member is mounted on the (i-1)-th-stage lifting member, and the arm assembly is mounted on the N-th-stage lifting member. In the action that the robot is to perform, depending on the content, the choice is to run the motors simultaneously to produce the lifting amount per stage in all of the lifting components, or to run the motors to produce the lifting amount per stage only in a subset of stages.

8. The control method according to claim 7, wherein, When the instructions given for controlling the robot are specific, the motor is controlled to produce the lifting amount of each stage only in the Nth stage lifting component.

9. The control method according to claim 8, wherein, The specific instruction is an instruction to cause the lifting unit to perform a lifting action, and the lifting amount of the lifting unit as a whole is below a predetermined threshold.

10. The control method according to claim 8 or 9, wherein, When the robot is a transport robot including a hand for carrying a workpiece and for transporting the workpiece, and the arm assembly is configured to connect multiple arms in a manner that allows each arm to rotate in a horizontal plane, and the hand is connected to the arm at the front end of the arm assembly in a manner that allows it to carry a workpiece and rotate in a horizontal plane, the specific instruction includes at least one of the following: an instruction to perform a lowering action by lowering the hand carrying the workpiece to unload the workpiece, and an instruction to perform a picking action by raising the unloaded hand to load the workpiece onto the hand.

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