Control method of a robot and robot system

Abstract

Control procedures for a robot, comprehensive: an inertial information reception step (S1) of receiving an output signal from an inertial sensor (24) that measures an actuation of an arm (22); a first step (S2) for adjusting a feedback gain, in which an adjustment is made to increase a feedback gain to be multiplied by the output signal or a signal generated from the output signal, according to a change in the actuation of the arm (22); a drive control step (S3) of controlling a drive of the arm (22) using the feedback gain increased in the first step (S2) to set a feedback gain; and a second step (S4) for adjusting a feedback gain, in which an adjustment is made to decrease the feedback gain after a predetermined time has elapsed since the first step (S2) for adjusting a feedback gain.

Description

[0001] The present application is based on and claims priority of JP application serial number 2023-156379, filed on 21 September 2023, the disclosure of which is hereby incorporated by reference in its entirety. BACKGROUND 1. Technical field

[0002] The present disclosure relates to a control method for a robot and a robot system. 2. State of the art

[0003] A robot described in JP 2005-242794 A includes a base, a first arm coupled to the base to be rotatable, a first motor driving the first arm, a first angle sensor detecting a rotation angle of the first motor, a first angular velocity sensor detecting an angular velocity of the first arm relative to the base, a second arm coupled to the first arm to be rotatable, a second motor driving the second arm, a second angle sensor detecting a rotation angle of the second motor, and a second angular velocity sensor detecting an angular velocity of the second arm relative to the first arm.The rotational angle of the first arm is detected using the output of the first angle sensor and the first angular velocity sensor, and the rotational angle of the second arm is detected using the output of the second angle sensor and the second angular velocity sensor. Furthermore, the detection results are fed back to perform vibration damping control of the robot.

[0004] However, the method described above can reduce vibrations in the operating directions of the first and second arms, but it cannot reduce vibrations in other directions, for example, vibrations along a rotational axis. Furthermore, if vibrations occur in a direction different from the operating direction, the method described above feeds them back, which can lead to instability in the operation of the first and second arms, thus potentially reducing the vibration damping effect. Therefore, the method described in JP 2005-242794 A does not achieve excellent vibration damping control.

[0005] EP 3 124 183 B1 relates to a robot system comprising a robot and a control device.

[0006] EP 2 703 130 B1 relates to a robot that can suppress vibrations in the robot, even when the number of sensors used is reduced.

[0007] US 11 167 415 B2 concerns a control device, a horizontal articulated robot arm, and a robot system.

[0008] US 9 999 974 B2 relates to a robot with multiple joints whose axes of rotation have different directions, whereby the robot suppresses vibrations.

[0009] US 9 481 088 B2 relates to a robot control device, a robot and a robot system.

[0010] US 2010 / 0 318 223 A1 concerns a robot that is capable of moving an end device attached to an arm to a desired position. SUMMARY

[0011] To solve the aforementioned problems, a method for a robot with the features of claim 1 and a robot system with the features of claim 10 are proposed according to the invention.

[0012] Dependent claims relate to preferred embodiments of the present invention.

[0013] According to one aspect of the present disclosure, a robot control method is provided which includes: an inertial information reception step of receiving an output signal from an inertial sensor that measures an actuation of an arm; a first step for setting a feedback gain, in which an adjustment is made to increase a feedback gain that is to be multiplied by the output signal or a signal generated from the output signal, according to a change in the actuation of the arm; a drive control step of controlling a drive of the arm using the feedback gain increased in the first step for setting a feedback gain;and a second step for adjusting a feedback gain, in which an adjustment is made to decrease the feedback gain after a predetermined time has elapsed since the first step for adjusting a feedback gain.

[0014] According to another aspect of the present disclosure, a robot system is provided which includes: a base; an arm which is driven with respect to the base; an inertial sensor which detects an actuation of the arm; and a controller which controls the drive of the arm, wherein the controller receives an output signal from the inertial sensor, performs an adjustment to increase a feedback gain which is to be multiplied by the output signal or a signal generated from the output signal, according to a change in the actuation of the arm, controls the drive of the arm using the feedback gain after the adjustment, and performs an adjustment to decrease the feedback gain after a predetermined time has elapsed since the increase in the feedback gain. BRIEF DESCRIPTION OF THE DRAWINGS Fig. Figure 1 shows a block diagram illustrating a configuration of a robot system according to a first embodiment. Fig. Figure 2 shows a diagram illustrating a robot that is part of the robot system of Fig. 1 is provided. Fig. Figure 3 shows a block diagram illustrating a control system used in the robot system of Fig. 1 is provided. Fig. Figure 4 shows a diagram illustrating a two-inertia system model of a rotary motion section of the robot. Fig. Figure 5 shows a diagram illustrating changes in an angular acceleration command, an angular velocity of a drive element, an angular velocity of a driven element, and a deflection angular velocity during a PTP actuation of an arm. Fig. Figure 6 shows a time diagram illustrating an example of the processing of a setting of a deflection angular velocity feedback gain. Fig. Figure 7 shows a diagram illustrating a residual vibration suppression effect of the arm. Fig. Figure 8 shows a flowchart illustrating a control procedure of the robot. Fig. Figure 9 shows a timing diagram illustrating an example of the processing of a setting of the deflection angular velocity feedback gain, which is carried out in a robot system according to a second embodiment. Fig. Figure 10 shows a timing diagram illustrating an example of the processing of a setting of the deflection angular velocity feedback gain, which is carried out in a robot system according to a third embodiment. Fig. Figure 11 shows a timing diagram illustrating an example of processing a setting of the deflection angular velocity feedback gain, which is performed in a robot system according to a fourth embodiment. Fig. Figure 12 shows a timing diagram illustrating an example of processing a setting of the deflection angular velocity feedback gain, which is performed in a robot system according to a fifth embodiment. Fig. Figure 13 shows a timing diagram illustrating an example of processing a setting of the deflection angular velocity feedback gain, which is performed in a robot system according to a sixth embodiment. Fig. Figure 14 shows a timing diagram illustrating an example of processing a setting of the deflection angular velocity feedback gain performed in a robot system according to a seventh embodiment. Fig. Figure 15 shows a timing diagram illustrating an example of processing a setting of the deflection angular velocity feedback gain, which is performed in a robot system according to an eighth embodiment. Fig. Figure 16 shows a timing diagram illustrating an example of the processing of a setting of the deflection angular velocity feedback gain, which is carried out in a robot system according to a ninth embodiment. Fig. Figure 17 shows a timing diagram illustrating an example of processing a setting of the deflection angular velocity feedback gain, which is carried out in a robot system according to a tenth embodiment. Fig. Figure 18 shows a timing diagram illustrating an example of the processing of a setting of the deflection angular velocity feedback gain, which is carried out in a robot system according to an eleventh embodiment. Fig. Figure 19 shows a diagram illustrating a robot provided in a robot system according to a twelfth embodiment. Fig. Figure 20 shows a block diagram illustrating a control system used in the robot system of Fig. 19 is provided. Fig. Figure 21 shows a diagram illustrating a two-inertia system model of a linear motion section of the robot. Fig. Figure 22 shows a diagram illustrating changes in an acceleration command, velocity, and speed during the actuation of a splined shaft. Fig. Figure 23 shows a time diagram illustrating an example of the processing of a setting of the deflection angular velocity feedback gain. Fig. Figure 24 shows a diagram illustrating a residual vibration suppression effect of the splined shaft. Fig. Figure 25 shows a diagram illustrating a robot provided in a robot system according to a thirteenth embodiment. Fig. Figure 26 shows a diagram illustrating a robot provided in a robot system according to a fourteenth embodiment. DESCRIPTION OF EXECUTION FORMS

[0015] A robot control method and a robot system of the present disclosure are described in detail below based on embodiments illustrated in the accompanying drawings.

[0016] Fig. Figure 1 shows a block diagram illustrating a configuration of a robot system according to a first embodiment. Fig. Figure 2 shows a diagram illustrating a robot that is part of the robot system of Fig. 1 is provided. Fig. Figure 3 shows a block diagram illustrating a control system used in the robot system of Fig. 1 is provided. Fig. Figure 4 shows a diagram illustrating a two-inertia system model of a rotary motion section of the robot. Fig. Figure 5 shows a diagram illustrating changes in an angular acceleration command Aref, an angular velocity ωm of a driving element, an angular velocity ωl of a driven element and a deflection angular velocity ωd during a PTP actuation of an arm. Fig. Figure 6 shows a time diagram illustrating an example of the processing of a setting of a deflection angular velocity feedback gain Kgp. Fig. Figure 7 shows a diagram illustrating a residual vibration suppression effect of the arm. Fig. Figure 8 shows a flowchart illustrating the robot's control procedure.

[0017] A robot system 1, which is in Fig. Figure 1 illustrates a robot 2, a control device 3, a host computer 4, and a programming handheld 5. A program for operating the robot 2 is created on the host computer 4. The programming handheld 5 is used to teach the robot 2 actions. Furthermore, the control device 3 includes a controller 30, which controls the robot 2's movement based on the program created by the host computer 4.

[0018] Fig. Figure 2 shows a diagram illustrating robot 2.

[0019] As in Fig. As illustrated in Figure 2, the robot 2 comprises a base 21, which is attached to a floor; an arm 22, which includes a base end section coupled to the base 21 and which rotates about a rotational axis J along a vertical direction relative to the base 21; a drive mechanism 23, which rotates the arm 22 about the rotational axis J relative to the base 21; and an inertial sensor 24, which is located at a tip end section of the arm 22. Furthermore, the drive mechanism 23 includes a reduction gear 231, which couples the base 21 and the arm 22; a motor 232, which includes a rotating shaft coupled to an input side of the reduction gear 231; and a position detector 233, which detects a rotation angle of a rotating shaft of the motor 232. Furthermore, the inertial sensor 24 is an angular velocity sensor that detects an angular velocity of the arm 22 around the axis of rotation J.Here, the inertial sensor 24 can be reformulated as an inertial sensor that measures the actuation of the arm, during which the arm 22 rotates about the axis of rotation J. An output signal from the inertial sensor 24 contains information regarding the inertia generated in the arm 22 by the actuation of the arm 22, i.e., inertial information. Additionally, the inertial information provides details about the inertia, such as angular velocity and acceleration, and the inertial sensor 24 can be reformulated as a sensor that transmits the inertial information. In the present embodiment, the angular velocity is used as the inertial information.

[0020] For the sake of simplicity of description, the rotation angle of the motor shaft of the motor 232 will in the following be referred to simply as the "rotation angle of the motor 232", and the motor shaft of the motor 232 will also be referred to simply as the "motor shaft".

[0021] The control device 3, for example, is configured with a computer and includes a processor that processes information, a memory that communicates with the processor, and an external interface. Furthermore, 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.

[0022] Such a control device 3 includes the controller 30, which controls the drive of the drive mechanism 23. The controller 30 has a circuit configuration that is described in Fig. Figure 3 illustrates the control system 30, which includes a position command generation unit 31, a position control unit 32, a velocity control unit 33, a current control unit 34, and a deflection angular velocity feedback generation unit 35.

[0023] The deflection angular velocity feedback generation unit 35 first obtains a motor shaft-equivalent arm angular velocity 912 by multiplying an angular velocity 911 of the arm 22, detected by the inertial sensor 24, by an arm angular velocity scaling coefficient Kgs. Furthermore, the deflection angular velocity feedback generation unit 35 obtains a motor shaft angular velocity 913, which is an angular velocity of the motor shaft, by temporally differentiating a motor shaft position 902, which is the rotation angle of the motor 232, detected by the position detector 233. Next, the deflection angular velocity feedback generation unit 35 obtains a deflection angular velocity 914 by subtracting the motor shaft angular velocity 913 from the motor shaft-equivalent arm angular velocity 912.Next, the deflection angular velocity feedback generating unit 35 receives a deflection angular velocity feedback 915 by multiplying the deflection angular velocity 914 by the deflection angular velocity feedback gain Kgp (a deflection angular velocity feedback base gain Kgpb and a deflection angular velocity feedback feedback gain coefficient Kgpc), which is a feedback gain. By using the deflection angular velocity feedback 915 obtained in this way, the vibration suppression effect of the arm 22 can be improved, as described below.

[0024] The position command generation unit 31 generates a position command 901 for the motor 232 based on the program created by the host computer 4.

[0025] The position control unit 32 first receives a position deviation 903, which is obtained by subtracting the motor shaft position 902 (the rotation angle of the motor 232), detected by the position detector 233, from the position command 901. Next, the position control unit 32 receives a speed command 904 by multiplying the position deviation 903 by a position loop proportional gain Kpp.

[0026] The speed control unit 33 is configured with proportional-integral control. The speed control unit 33 first receives a speed loop instruction 905 by adding the speed instruction 904 and the deflection angular velocity feedback 915, which is generated by the deflection angular velocity feedback generation unit 35. Next, the speed control unit 33 receives a current instruction 906 by adding an integral term, obtained by multiplying an integral value of the speed loop instruction 905 by a speed loop integral gain Kvi, to a proportional term, obtained by multiplying the speed loop instruction 905 by a speed loop proportional gain Kvp.

[0027] The current control unit 34 controls a current 907 to drive the motor 232 in accordance with the current command 906; that is, it controls the current 907 to follow the current command 906. The motor 232 is driven by the current 907, which is controlled by the current control unit 34, and a load 29, coupled to the motor 232, rotates. Here, the load 29 is the sum of the moments of inertia of the motor shaft and the drive elements (the reduction gear 231, the arm 22, the inertia sensor 24, and the like) that are coupled to the motor shaft.

[0028] The circuit configuration of controller 30 is briefly described above. Next, it is illustrated... Fig. 4 A two-inertia system model 600 of a rotary motion section of the robot 2. In such a two-inertia system model 600, a drive element 601, which has a motor-shaft-side moment of inertia Jm, and a driven element 602, which has a load-side moment of inertia JI, are connected by a spring element 603, which has a spring constant Ks. In such a two-inertia system model 600, the drive element 601 and the driven element 602 rotate about a rotary motion axis 604, and the spring element 603 is twisted and deformed by the rotary motion about the rotary motion axis 604.

[0029] In robot 2, the spring element 603 is primarily configured with the motor shaft, the reduction gear 231, and the arm 22. Therefore, the spring constant Ks is a combined value of the spring constants resulting from the deformation of the motor shaft, the reduction gear 231, and the arm 22. Furthermore, in robot 2, the motor shaft-side moment of inertia Jm is primarily the moment of inertia of the motor shaft. Additionally, in robot 2, the load-side moment of inertia JI is the sum of the moments of inertia about the axis of rotation J of the drive elements coupled to the motor shaft, namely primarily the reduction gear 231, the arm 22, and the inertial sensor 24.

[0030] Additionally, in robot 2, the motor shaft equivalent arm angular velocity 912, obtained by multiplying the angular velocity 911 of arm 22, detected by the inertial sensor 24, by the arm angular velocity scaling coefficient Kgs, corresponds to the angular velocity of the driven element 602 about the axis of rotation 604, i.e., the angular velocity ωl of the driven element. Meanwhile, in robot 2, the motor shaft angular velocity 913, obtained by differentiating the motor shaft position 902, detected by the position detector 233, corresponds to the angular velocity of the drive element 601 about the axis of rotation 604, i.e., the angular velocity ωm of the drive element. Furthermore, a drive torque for the drive element 601, in order to rotate the driven element 602, acts on the spring element 603. Therefore, the spring element 603 is twisted.The deflection angular velocity ωd, which is the velocity at which the spring element 603 is twisted, can be obtained by subtracting the angular velocity ωm of the driving element 601 from the angular velocity ωl of the driven element 602, as shown in equation (1) below. ωd=ωl−ωm

[0031] Here, if the oscillation of the driven element 602, caused by the twisting of the spring element 603, is defined as a "deflection oscillation," then this "deflection oscillation" is the primary cause of the oscillation of the arm 22. Therefore, by damping the displacement oscillation, the oscillation of the arm 22 can be effectively suppressed, and an excellent vibration suppression effect can be demonstrated. The displacement angular velocity feedback 915, generated by the displacement angular velocity feedback generation unit 35, has a damping effect on such a displacement oscillation, and the damping rate of the displacement oscillation is adjusted by changing the displacement angular velocity feedback gain Kgp according to the angular velocity of the arm 22.

[0032] Next, the deflection angular velocity feedback gain Kgp is described in detail. The deflection angular velocity feedback gain Kgp is obtained by multiplying the deflection angular velocity feedback base gain Kgpb, which is a feedback base gain, by the deflection angular velocity feedback feedback gain coefficient Kgpc, which is a feedback gain coefficient. That is, the deflection angular velocity feedback gain Kgp is represented by equation (2) below. Kgp=Kgpc×Kgpb

[0033] Among these, the deflection angular velocity feedback base gain Kgpb is adjusted according to the load 29 or the orientation of the arm 22 and is kept constant in the present embodiment. On the other hand, the deflection angular velocity feedback gain coefficient Kgpc is changed according to the direction of rotation of the arm 22, that is, the angular velocity about the axis of rotation J. As described above, the deflection angular velocity feedback gain coefficient Kgpc is easily adjusted by the method of changing it while keeping the deflection angular velocity feedback base gain Kgpb constant. The timing of the change in the deflection angular velocity feedback gain coefficient Kgpc is described in detail below.

[0034] Fig. Figure 5 illustrates changes in the angular acceleration command Aref, the angular velocity ωm of the drive element, the angular velocity ωl of the driven element, and the deflection angular velocity ωd during the point-to-point (PTP) actuation of the arm 22. For the sake of simplicity, the deflection angular velocity ωd is shown on an enlarged scale relative to the angular velocity ωl of the driven element and the angular velocity ωm of the drive element.

[0035] As in Fig. As illustrated in Figure 5, the angular acceleration command Aref changes at the start of acceleration if the angular acceleration increase point is N1s and the angular acceleration increase endpoint is N1e; at the end of acceleration if the angular acceleration decrease point is N2s and the angular acceleration decrease endpoint is N2e; at the start of deceleration if the angular acceleration increase point is N3s and the angular acceleration increase endpoint is N3e; and at the end of deceleration if the angular acceleration decrease point is N4s and the angular acceleration decrease endpoint is N4e. Additionally, there is a constant velocity section between the angular acceleration decrease endpoint N2e and the angular acceleration increase start point N3s.

[0036] The oscillation of the displacement angular velocity ωd (hereinafter also referred to as "displacement oscillation") increases at points of change in angular acceleration where the angular acceleration command Aref changes, namely the starting point of the angular acceleration increase N1s, the end point of the angular acceleration increase N1e, the starting point of the angular acceleration decrease N2s, the end point of the angular acceleration decrease N2e, the starting point of the angular acceleration increase N3s, the end point of the angular acceleration increase N3e, the starting point of the angular acceleration decrease N4s, and the end point of the angular acceleration decrease N4e. This phenomenon occurs because the drive torque for accelerating and decelerating the driven element 602 is transmitted to the drive element 601 via the spring element 603, causing the spring element 603 to twist at the eight points described above.

[0037] In this context, in the robot system 1, the deflection angular velocity feedback gain Kgp is increased at a time determined based on each of the eight points N1s, N1e, N2s, N2e, N3s, N3e, N4s and N4e described above, where the deflection oscillation increases, thereby reducing the oscillation of the driven element 602, i.e., the arm 22.

[0038] In particular, the deflection angular velocity feedback gain Kgp is increased with a first time point T1, determined based on the angular acceleration increase start point N1s, a second time point T2, determined based on the angular acceleration increase end point N1e, a third time point T3, determined based on the angular acceleration decrease start point N2s, a fourth time point T4, determined based on the angular acceleration decrease end point N2e, a fifth time point T5, determined based on the angular acceleration increase start point N3s, a sixth time point T6, determined based on the angular acceleration increase end point N3e, a seventh time point T7, determined based on the angular acceleration decrease start point N4s, and an eighth time point T8, determined based on the angular acceleration decrease end point N4e, as starting points.which reduces the vibration of arm 22.

[0039] In the prior art, although the deflection angular velocity feedback gain Kgp is set according to the orientation of the robot 2 or the size of the load 29, the deflection angular velocity feedback gain Kgp is not set according to the angular velocity of the arm 22 as in the present embodiment.

[0040] In the present embodiment, the first time point T1 is set to the same time point as the angular acceleration increase starting point N1s, the second time point T2 is set to the same time point as the angular acceleration increase end point N1e, the third time point T3 is set to the same time point as the angular acceleration decrease starting point N2s, the fourth time point T4 is set to the same time point as the angular acceleration decrease end point N2e, the fifth time point T5 is set to the same time point as the angular acceleration increase starting point N3s, the sixth time point T6 is set to the same time point as the angular acceleration increase end point N3e, the seventh time point T7 is set to the same time point as the angular acceleration decrease starting point N4s, and the eighth time point T8 is set to the same time point as the angular acceleration decrease end point N4e.As a result, the deflection angular velocity feedback gain Kgp can be increased without delay for each of the angular acceleration change points: the angular acceleration increase start point N1s, the angular acceleration increase end point N1e, the angular acceleration decrease start point N2s, the angular acceleration decrease end point N2e, the angular acceleration increase start point N3s, the angular acceleration increase end point N3e, the angular acceleration decrease start point N4s and the angular acceleration decrease end point N4e, thereby obtaining a higher vibration suppression effect.

[0041] However, the present disclosure is not limited to this, and, for example, the first time T1 can be a time that is later than the angular acceleration increase starting point N1s by a predetermined time Δt, or it can be a time that is earlier than the angular acceleration increase starting point N1s by a predetermined time Δt. The same applies to the second, third, fourth, fifth, sixth, seventh, and eighth times T2, T3, T4, T5, T6, T7, and T8, which differ from the first time T1. In addition, the predetermined time Δt can differ between two or more times that are optionally selected from the first, second, third, fourth, fifth, sixth, seventh, and eighth times T1, T2, T3, T4, T5, T6, T7, and T8.

[0042] For the sake of simplicity, the first time point T1 is described below as the starting point N1s for the increase in angular acceleration, the second time point T2 is described as the endpoint N1e for the increase in angular acceleration, the third time point T3 is described as the starting point N2s for the decrease in angular acceleration, the fourth time point T4 is described as the endpoint N2e for the decrease in angular acceleration, the fifth time point T5 is described as the starting point N3s for the increase in angular acceleration, the sixth time point T6 is described as the endpoint N3e for the increase in angular acceleration, the seventh time point T7 is described as the starting point N4s for the decrease in angular acceleration, and the eighth time point T8 is described as the endpoint N4e for the decrease in angular acceleration.

[0043] Here, destabilization factors of the control system that can occur due to an increase in the deflection angular velocity feedback gain Kgp are considered, for example, (A) a destabilization of the physical control system due to elements forming a drive system, and (B) a reduced control stability due to the wrapping of oscillations in directions other than a rotational direction. Destabilization factor (A) refers to a destabilization of the deflection angular velocity feedback control system, which is determined by the motor shaft-side moment of inertia Jm, the load-side moment of inertia JI, and the spring constant Ks in the two-inertia system model 600.Meanwhile, the destabilization factor (B) refers to a destabilization of the deflection angular velocity feedback control that occurs when the arm 22 oscillates in directions other than the rotational direction due to the elastic deformation of each element forming the robot 2, particularly in the vertical direction. The inertial sensor 24 detects this oscillation (hereinafter also referred to as "non-rotational oscillation") as noise, and the controller 30 uses this noise for control. The non-rotational oscillation occurs due to the wrapping of the deflection oscillation in the rotational direction. Therefore, the non-rotational oscillation increases with a delay relative to the deflection oscillation in the rotational direction.

[0044] In this respect, in robot system 1, by using the property that the oscillation in the non-rotational direction increases with a delay relative to the displacement oscillation in the rotational direction, the displacement angular velocity feedback gain Kgp is temporarily increased at the eight angular acceleration change points described above, where the displacement oscillation increases in the rotational direction. These points are the angular acceleration increase start point N1s, the angular acceleration increase end point N1e, the angular acceleration decrease start point N2s, the angular acceleration decrease end point N2e, the angular acceleration increase start point N3s, the angular acceleration increase end point N3e, the angular acceleration decrease start point N4s, and the angular acceleration decrease end point N4e, which serve as the starting points to dampen the displacement oscillation in the rotational direction.This suppresses the destabilization of the control system due to the amplification of the oscillation in the non-rotational direction. As described above, by temporarily increasing the deflection angular velocity feedback gain Kgp, the deflection angular velocity feedback gain Kgp can be reduced again when the oscillation in the non-rotational direction increases, thereby reducing or preferably eliminating the influence of the destabilization factor (B).

[0045] In the prior art, due to the destabilization factor (B), the deflection angular velocity feedback gain Kgp cannot be increased to a limit (maximum value) of the destabilization factor (A). On the other hand, with the control method of the present embodiment as described above, the influence of the destabilization factor (B) is reduced, so that the deflection angular velocity feedback gain Kgp can be increased to the limit of the destabilization factor (A). Therefore, the deflection angular velocity feedback gain Kgp can be set higher than in the prior art without destabilizing the control system, and the vibration suppression effect of the arm 22 can be improved.

[0046] Fig. Figure 6 shows a time diagram illustrating an example of the processing of a setting of the deflection angular velocity feedback gain Kgp with the eight points described above, which are the change points of the angular acceleration command Aref, that is, the angular acceleration increase start point N1s, the angular acceleration increase end point N1e, the angular acceleration decrease start point N2s, the angular acceleration decrease end point N2e, the angular acceleration increase start point N3s, the angular acceleration increase end point N3e, the angular acceleration decrease start point N4s and the angular acceleration decrease end point N4e, as the starting points. Fig. Figure 6 illustrates changes to the angular acceleration command Aref, a velocity command Vref, and the deflection angular velocity feedback gain coefficient Kgpc.

[0047] In the illustrated example, the deflection angular velocity feedback gain coefficient Kgpc is increased from 1, which is the reference value, to 3 for a time dt (seconds) with all points—the angular acceleration increase start point N1s, the angular acceleration increase end point N1e, the angular acceleration decrease start point N2s, the angular acceleration decrease end point N2e, the angular acceleration increase start point N3s, the angular acceleration increase end point N3e, the angular acceleration decrease start point N4s, and the angular acceleration decrease end point N4e—as the starting points. The deflection angular velocity feedback gain coefficient Kgpc is increased from 1 to 3, and then, after the time dt has elapsed, the deflection angular velocity feedback gain coefficient Kgpc is decreased from 3 back to 1, i.e., to the reference value.Therefore, the controller 30 controls the drive of the motor 232 using the deflection angular velocity feedback gain coefficient Kgpc = 3 until the deflection angular velocity feedback gain coefficient Kgpc is increased from 1 to 3 and then decreased back to 1, and controls the drive of the motor 232 using the deflection angular velocity feedback gain coefficient Kgpc = 1 at other times. As described above, the deflection angular velocity feedback gain coefficient Kgpc is easily adjusted by increasing and decreasing it relative to the reference value of 1.

[0048] The deflection angular velocity feedback gain Kgp is obtained by multiplying the deflection angular velocity feedback base gain Kgpb by the deflection angular velocity feedback gain coefficient Kgpc, as shown in equation (2) above. Therefore, increasing the deflection angular velocity feedback gain coefficient Kgpc to 3 increases the deflection angular velocity feedback gain Kgp by a factor of three.By increasing the deflection angular velocity feedback gain Kgp by three times, the effect of damping the deflection oscillation is increased, and it is possible to reduce the deflection oscillation that increases during operation with each of the angular acceleration change points: the angular acceleration increase start point N1s, the angular acceleration increase end point N1e, the angular acceleration decrease start point N2s, the angular acceleration decrease end point N2e, the angular acceleration increase start point N3s and the angular acceleration increase end point N3e, as the start points, and the residual oscillation that increases during stopping with each of the angular acceleration change points, that is, the angular acceleration decrease start point N4s and the angular acceleration decrease end point N4e, as the start points.

[0049] Adjusting the deflection angular velocity feedback gain coefficient Kgpc at the angular acceleration increase start point N1s and the angular acceleration increase end point N1e reduces the deflection oscillation of the arm 22 during acceleration operation. Similarly, adjusting the deflection angular velocity feedback gain coefficient Kgpc at the angular acceleration decrease start point N2s and the angular acceleration decrease end point N2e reduces the deflection oscillation of the arm 22 during constant velocity operation. Furthermore, adjusting the deflection angular velocity feedback gain coefficient Kgpc at the angular acceleration increase start point N3s and the angular acceleration increase end point N3e reduces the deflection oscillation of the arm 22 during deceleration operation.Furthermore, adjusting the deflection angular velocity feedback gain coefficient Kgpc at the angular acceleration decrease start point N4s and the angular acceleration decrease end point N4e has the effect of reducing the residual oscillation of the arm 22.

[0050] In the illustrated example, the deflection angular velocity feedback gain coefficient Kgpc is increased from 1 to 3 with all points—the angular acceleration increase start point N1s, the angular acceleration increase end point N1e, the angular acceleration decrease start point N2s, the angular acceleration decrease end point N2e, the angular acceleration increase start point N3s, the angular acceleration increase end point N3e, the angular acceleration decrease start point N4s, and the angular acceleration decrease end point N4e—as the starting points. However, the present disclosure is not limited to this, and the deflection angular velocity feedback gain coefficient Kgpc only needs to be increased from 1 to 3 with at least one of the eight points as the starting point. Consequently, at least the oscillation that increases with the point as the starting point can be effectively suppressed.Additionally, in the illustrated example, the deflection angular velocity feedback gain coefficient Kgpc is increased to 3, but the value of the deflection angular velocity feedback gain coefficient Kgpc is not particularly limited.

[0051] If the time dt during which the deflection angular velocity feedback gain coefficient Kgpc is increased to 3 is too long, the oscillation in the non-rotational direction may increase during this time, potentially destabilizing the deflection angular velocity feedback control. Conversely, if the time dt is too short, the vibration suppression effect described above may not be sufficiently effective. The time dt is not particularly limited and varies depending on the configuration of the robot 2 and the actuation of the arm 22. However, for example, the time dt is preferably approximately 0.1 seconds or more and 2 seconds or less, which corresponds to 0.1 to 2 times the natural oscillation period of the deflection oscillation.Additionally, in the present embodiment, the time dt is the same at all points: the angular acceleration increase start point N1s, the angular acceleration increase end point N1e, the angular acceleration decrease start point N2s, the angular acceleration decrease end point N2e, the angular acceleration increase start point N3s, the angular acceleration increase end point N3e, the angular acceleration decrease start point N4s, and the angular acceleration decrease end point N4e. This simplifies the processing of setting the deflection angular velocity feedback gain coefficient Kgpc.

[0052] Fig. Figure 7 shows a diagram illustrating the residual vibration suppression effect of the arm 22 and comparing the residual vibration in the direction of rotation occurring at the tip end section of the arm 22 between A, where the deflection angular velocity feedback gain Kgp is kept constant, and B, where the deflection angular velocity feedback gain Kgp is changed synchronously with the angular acceleration change as in the present embodiment. When the deflection angular velocity feedback gain Kgp is kept constant, overshoot beyond the target position occurs, and then the residual vibration is damped, and operation stops at the target position.On the other hand, if the deflection angular velocity feedback gain Kgp is changed synchronously with the angular acceleration change, as in the present embodiment, the operation stops immediately at the target position with almost no overshoot or residual vibration. Therefore, it can be seen that an excellent vibration suppression effect is demonstrated.

[0053] For example, if partial assembly work or similar tasks are performed using robot 2, excessive force is exerted on the workpiece due to overshoot, leading to workpiece damage or variations in the position of the workpiece being picked up, thus reducing product quality. Additionally, residual vibration increases the cycle time of the assembly work, resulting in decreased productivity. Therefore, a high-quality product with high productivity can be manufactured using robot system 1, which does not produce overshoot.

[0054] In the present embodiment, the angular acceleration increase start point N1s, the angular acceleration increase end point N1e, the angular acceleration decrease start point N2s, the angular acceleration decrease end point N2e, the angular acceleration increase start point N3s, the angular acceleration increase end point N3e, the angular acceleration decrease start point N4s, and the angular acceleration decrease end point N4e are detected based on the angular acceleration command Aref, which is the position command of the arm 22. With this method, each of the points N1s, N1e, N2s, N2e, N3s, N3e, N4s, and N4e can be detected more accurately. Therefore, a higher vibration suppression effect with excellent reproducibility can be demonstrated.

[0055] The method for acquiring each of the points N1s, N1e, N2s, N2e, N3s, N3e, N4s, and N4e is not particularly limited. For example, each of the points N1s, N1e, N2s, N2e, N3s, N3e, N4s, and N4e can be acquired using the acceleration obtained by second-order differentiation of the motor shaft position 902, which is acquired by the position detector 233. However, the acceleration obtained by second-order differentiation of the motor shaft position 902 exhibits significant ripple (pulsating AC components), which can lead to poorer acquisition accuracy for each of the points N1s, N1e, N2s, N2e, N3s, N3e, N4s, and N4e compared to acquisition based on the angular acceleration command Aref. Therefore, it is preferable to capture each of the points N1s, N1e, N2s, N2e, N3s, N3e, N4s and N4e based on the angular acceleration command Aref.

[0056] From the above description, as in Fig. As shown in Figure 8, the control method of the robot 2, as described above, comprises an inertial information reception step S1 for receiving the angular velocity 911, which is the output signal from the inertial sensor 24 that measures the actuation of the arm 22; a first step S2 for adjusting a feedback gain, in which an adjustment is made to increase the deflection angular velocity feedback gain Kgp, which is to be multiplied by the angular velocity 911 or the signal generated from the angular velocity 911, in the present embodiment the deflection angular velocity 914 generated from the angular velocity 911 according to the change in the angular velocity of the arm 22.The system includes a drive control step S3 for controlling the drive of the arm 22 using the deflection angular velocity feedback gain Kgp increased in the first step S2 for setting a feedback gain, and a second step S4 for setting a feedback gain, in which an adjustment is made to decrease the deflection angular velocity feedback gain Kgp after the time dt has elapsed since the first step S2 for setting a feedback gain. With such a control method, the

[0057] The deflection angular velocity feedback gain Kgp can be increased to the limit of the destabilization factor (A) without destabilizing the control system. Therefore, the deflection angular velocity feedback gain Kgp can be set higher than in the prior art, and the vibration of the arm 22 can be suppressed more effectively.

[0058] The robot system 1 is described above. The control method of the robot 2, used in such a robot system 1, includes, as described above, the inertial information reception step S1 for receiving the angular velocity 911, which is contained in the output signal from the inertial sensor 24 that measures the actuation of the arm 22; the first step S2 for setting a feedback gain, in which an adjustment is made to increase the deflection angular velocity feedback gain Kgp, which is the feedback gain to be multiplied by the angular velocity 911 or the signal generated from the angular velocity 911, in the present embodiment the deflection angular velocity 914 generated from the angular velocity 911 according to the change in the actuation of the arm 22.The drive control step S3 of controlling the drive of the arm 22 uses the deflection angular velocity feedback gain Kgp increased in the first step S2 for setting a feedback gain, and the second step S4 for setting a feedback gain, in which an adjustment is made to decrease the deflection angular velocity feedback gain Kgp after the time dt, which is the predetermined time, has elapsed since the first step S2 for setting a feedback gain. With such a control method, the deflection angular velocity feedback gain Kgp can be increased to the limit of the destabilization factor (A) without causing destabilization of the control. Therefore, the deflection angular velocity feedback gain Kgp can be set higher than in the prior art, and the vibration of the arm 22 can be suppressed more effectively.

[0059] Additionally, as described above, in the control procedure of robot 2, in the first step S2, the deflection angular velocity feedback gain coefficient Kgpc is changed from 1, which is the reference value, to a value higher than the reference value, and in the second step S4, the deflection angular velocity feedback gain coefficient Kgpc is reset to 1, which is the reference value. As a result, the deflection angular velocity feedback gain Kgp is slightly adjusted.

[0060] Furthermore, as described above, the output signal from the inertial sensor 24 contains the inertial information, which is the information regarding the inertia generated in the arm 22 by the actuation of the arm 22, that is, the angular velocity. In the control procedure of the robot 2, the first step S2 for setting a feedback gain is performed at at least one of the following: the angular acceleration increase start point N1s, which is the first time T1 at which the increase in angular velocity begins at the start of the acceleration of the arm 22; the angular acceleration increase end point N1e, which is the second time T2 at which the increase in angular velocity ends at the start of the acceleration of the arm 22; the angular acceleration decrease start point N2s, which is the third time T3 at which the decrease in angular velocity begins at the end of the acceleration of the arm 22.the angular acceleration decrease endpoint N2e, which is the fourth time T4, at which the decrease in angular velocity ends at the end of the acceleration of arm 22; the angular acceleration increase start point N3s, which is the fifth time T5, at which the increase in angular velocity begins at the beginning of the deceleration of arm 22; the angular acceleration increase endpoint N3e, which is the sixth time T6, at which the increase in angular velocity ends at the beginning of the deceleration of arm 22; the angular acceleration decrease start point N4s, which is the seventh time T7, at which the decrease in angular velocity begins at the end of the deceleration of arm 22; and the angular acceleration decrease endpoint N4e, which is the eighth time T8, at which the decrease in angular velocity ends at the end of the deceleration of arm 22. As a result, the oscillation, which increases with each of the points as the starting point,can be effectively reduced.

[0061] Additionally, as described above, in the control procedure of robot 2, the deflection angular velocity feedback gain Kgp is obtained by multiplying the deflection angular velocity feedback base gain Kgpb, which is the feedback base gain that serves as the reference for the deflection angular velocity feedback gain Kgp, by the deflection angular velocity feedback gain coefficient Kgpc, which is the feedback gain coefficient. In the first step S2 for setting a feedback gain and in the second step S4 for setting a feedback gain, the deflection angular velocity feedback gain Kgp is adjusted by changing the deflection angular velocity feedback gain coefficient Kgpc. As a result, the deflection angular velocity feedback gain Kgp is easily adjusted.

[0062] Furthermore, as described above, the robot 2's control method detects the change in the angular velocity of arm 22 based on the angular acceleration command Aref, which is the position command for arm 22. This method allows for more precise detection of the angular acceleration increase start point N1s, the angular acceleration increase end point N1e, the angular acceleration decrease start point N2s, the angular acceleration decrease end point N2e, the angular acceleration increase start point N3s, the angular acceleration increase end point N3e, the angular acceleration decrease start point N4s, and the angular acceleration decrease end point N4e. Therefore, a higher vibration suppression effect with excellent reproducibility can be demonstrated.

[0063] Furthermore, as described above, the robot system 1 includes the base 21, the arm 22 which is driven in relation to the base 21, the inertial sensor 24 which detects the angular velocity which is the actuation of the arm 22, and the controller 30 which controls the drive of the arm 22.The controller 30 receives the angular velocity 911, which is the output signal from the inertial sensor 24, performs an adjustment to increase the deflection angular velocity feedback gain Kgp, which is the feedback gain to be multiplied by the angular velocity 911 or the signal generated from the angular velocity 911, in the present embodiment the deflection angular velocity 914 generated from the angular velocity 911 according to the change in the angular velocity of the arm 22, controls the drive of the arm 22 using the deflection angular velocity feedback gain Kgp after the adjustment, and performs an adjustment to decrease the deflection angular velocity feedback gain Kgp after the time dt, which is the predetermined time, has elapsed since the increase in the deflection angular velocity feedback gain Kgp.With such a configuration, the deflection angular velocity feedback gain Kgp can be increased to the limit of the destabilization factor (A) without destabilizing the control system. Therefore, the deflection angular velocity feedback gain Kgp can be set higher than in the prior art, and the vibration of the arm 22 can be suppressed more effectively.

[0064] Furthermore, as described above, the robot system 1 includes the motor 232, which rotates the arm 22 about the axis of rotation J with respect to the base 21, and the position detector 233, which detects the rotation angle of the motor 232. Additionally, the inertial sensor 24 detects the angular velocity of the arm 22 about the axis of rotation J. Furthermore, the controller 30 receives the deflection angular velocity 914 based on the motor shaft equivalent arm angular velocity 912, which is the angular velocity of the arm 22 detected by the inertial sensor 24, and the motor shaft angular velocity 913, which is the angular velocity of the motor 232 detected by the position detector 233, and multiplies the deflection angular velocity 914 by the deflection angular velocity feedback gain Kgp.By using the deflection angular velocity feedback 915 obtained in this way, the vibration suppression effect of the arm 22 can be improved.

[0065] Fig. Figure 9 shows a timing diagram illustrating an example of the processing of a setting of the deflection angular velocity feedback gain Kgp, which is carried out in a robot system according to a second embodiment.

[0066] The present embodiment is the same as the first embodiment described above, except that the method for adjusting the deflection angular velocity feedback gain Kgp differs. In the following description, the present embodiment is described with a focus on its differences from the first embodiment described above, and the description of identical items is not repeated. Additionally, in the drawings of the present embodiment, the same configurations as those of the embodiment described above are designated with the same reference numerals.

[0067] In the first step S2 for setting a feedback gain of the present embodiment, the deflection angular velocity feedback gain Kgp is set so that it differs between any two points selected from the angular acceleration increase start point N1s, the angular acceleration increase end point N1e, the angular acceleration decrease start point N2s, the angular acceleration decrease end point N2e, the angular acceleration increase start point N3s, the angular acceleration increase end point N3e, the angular acceleration decrease start point N4s and the angular acceleration decrease end point N4e.

[0068] In the Fig. In the illustrated example 9, the deflection angular velocity feedback gain coefficient Kgpc is set to 3 at the angular acceleration increase start point N1s, 2 at the angular acceleration increase end point N1e, 1 at the angular acceleration decrease start point N2s, 3 at the angular acceleration decrease end point N2e, 2 at the angular acceleration increase start point N3s, 3 at the angular acceleration increase end point N3e, 3 at the angular acceleration decrease start point N4s, and 2 at the angular acceleration decrease end point N4e. As described above, by setting the deflection angular velocity feedback gain coefficient Kgpc for each angular acceleration change point, the oscillation of arm 22 during acceleration operation, the oscillation during deceleration operation, and the residual oscillation after stopping can be effectively suppressed.

[0069] As described above, in the control procedure of the robot 2 of the present embodiment, in the first step S2, the deflection angular velocity feedback gain Kgp is set so that it differs between any two time points selected from the angular acceleration increase start point N1s, which is the first time T1, the angular acceleration increase end point N1e, which is the second time T2, the angular acceleration decrease start point N2s, which is the third time T3, the angular acceleration decrease end point N2e, which is the fourth time T4, the angular acceleration increase start point N3s, which is the fifth time T5, the angular acceleration increase end point N3e, which is the sixth time T6, the angular acceleration decrease start point, which is the seventh time T7, and the angular acceleration decrease end point N4e, which is the eighth time T8.As described above, by adjusting the deflection angular velocity feedback gain Kgp for each angular acceleration change point, the oscillation of the arm 22 during acceleration operation, the oscillation during deceleration operation, and the residual oscillation after stopping can be effectively suppressed.

[0070] Even in the second embodiment, as described above, the same effect as in the first embodiment described above can be demonstrated.

[0071] Fig. Figure 10 shows a timing diagram illustrating an example of the processing of a setting of the deflection angular velocity feedback gain Kgp, which is carried out in a robot system according to a third embodiment.

[0072] The present embodiment is the same as the first embodiment described above, except that the method for adjusting the deflection angular velocity feedback gain Kgp differs. In the following description, the present embodiment is described with a focus on its differences from the first embodiment described above, and the description of identical items is not repeated. Additionally, in the drawings of the present embodiment, the same configurations as those of the embodiment described above are designated with the same reference numerals.

[0073] In the first step S2 for setting a feedback gain of the present embodiment, the rise and fall of the deflection angular velocity feedback gain coefficient Kgpc are gradually or continuously changed for at least one of the angular acceleration increase start point N1s, the angular acceleration increase end point N1e, the angular acceleration decrease start point N2s, the angular acceleration decrease end point N2e, the angular acceleration increase start point N3s, the angular acceleration increase end point N3e, the angular acceleration decrease start point N4s and the angular acceleration decrease end point N4e.

[0074] In the Fig. In the illustrated example 10, the increase in the deflection angular velocity feedback gain coefficient Kgpc at the angular acceleration increase start point N1s and the angular acceleration increase end point N1e is continuously increased. Additionally, the decrease in the deflection angular velocity feedback gain coefficient Kgpc at the angular acceleration decrease start point N2s and the angular acceleration decrease end point N2e is continuously decreased. Furthermore, the increase in the deflection angular velocity feedback gain coefficient Kgpc at the angular acceleration increase start point N3s and the angular acceleration increase end point N3e is continuously increased, and the decrease is continuously decreased.Furthermore, at the angular acceleration decrease start point N4s, the increase in the deflection angular velocity feedback gain coefficient Kgpc is continuously increased and at a lower rate of change than at the angular acceleration increase start point N1s, the angular acceleration increase end point N1e, the angular acceleration increase start point N3s, and the angular acceleration increase end point N3e. Conversely, at the angular acceleration decrease end point N4e, the decrease in the deflection angular velocity feedback gain coefficient Kgpc is continuously decreased and at a lower rate of change than at the angular acceleration decrease start point N2s, the angular acceleration decrease end point N2e, the angular acceleration increase start point N3s, and the angular acceleration increase end point N3e.

[0075] As described above, by continuously increasing the rate of change of the deflection angular velocity feedback gain coefficient Kgpc, the processing of an increase in the deflection angular velocity feedback gain Kgp for the point of change in angular acceleration can be delayed. Therefore, the influence of the twisting of the spring element 603 due to the change in angular acceleration can be suppressed, and the destabilization of the control system can be effectively suppressed. Conversely, by continuously decreasing the rate of change of the deflection angular velocity feedback gain coefficient Kgpc, the processing of a decrease in the deflection angular velocity feedback gain Kgp can be delayed, thereby correspondingly extending the vibration suppression effect.

[0076] Even in the third embodiment, as described above, the same effect as in the first embodiment described above can be demonstrated.

[0077] Fig. Figure 11 shows a timing diagram illustrating an example of the processing of a setting of the deflection angular velocity feedback gain Kgp, which is carried out in a robot system according to a fourth embodiment.

[0078] The present embodiment is the same as the first embodiment described above, except that the method for adjusting the deflection angular velocity feedback gain Kgp differs. In the following description, the present embodiment is described with a focus on its differences from the first embodiment described above, and the description of identical items is not repeated. Additionally, in the drawings of the present embodiment, the same configurations as those of the embodiment described above are designated with the same reference numerals.

[0079] In the third embodiment described above, the rise and fall of the deflection angular velocity feedback gain coefficient Kgpc are changed linearly. That is, the rate of change is constant. On the other hand, in the present embodiment, as described in Fig. Figure 11 illustrates the rise and fall of the deflection angular velocity feedback gain coefficient Kgpc in a quadratic curve.

[0080] By increasing the rate of change of the deflection angular velocity feedback gain coefficient Kgpc in a quadratic curve, the deflection angular velocity feedback gain Kgp can be increased in a short time, thus improving the vibration suppression effect. Additionally, the rate of change of the deflection angular velocity feedback gain Kgp decreases over time, thus suppressing control destabilization. Conversely, by decreasing the rate of change of the deflection angular velocity feedback gain coefficient Kgpc in a quadratic curve, the processing of a decrease in the deflection angular velocity feedback gain Kgp can be delayed, thereby prolonging the vibration suppression effect.

[0081] Even in the fourth embodiment, as described above, the same effect as in the first embodiment described above can be demonstrated.

[0082] Fig. Figure 12 shows a timing diagram illustrating an example of processing a setting of the deflection angular velocity feedback gain Kgp, which is performed in a robot system according to a fifth embodiment.

[0083] The present embodiment is the same as the first embodiment described above, except that the method for adjusting the deflection angular velocity feedback gain Kgp differs. In the following description, the present embodiment is described with a focus on its differences from the first embodiment described above, and the description of identical items is not repeated. Additionally, in the drawings of the present embodiment, the same configurations as those of the embodiment described above are designated with the same reference numerals.

[0084] In the present embodiment, as in Fig. Figure 12 illustrates a process where an upper limit, Lim, is set for the deflection angular velocity feedback gain, Kgp, and the deflection angular velocity feedback gain, Kgp, is adjusted so that it does not exceed the upper limit, Lim. The adjustment procedure is not particularly restricted and could, for example, be a method for adjusting the deflection angular velocity feedback gain coefficient, Kgpc, so that it does not exceed the upper limit, Lim. Additionally, a method can be used in which the deflection angular velocity feedback gain coefficient, Kgpc, is set independently of the upper limit, Lim, and if the deflection angular velocity feedback gain, Kgp, exceeds the upper limit, Lim after the adjustment, the deflection angular velocity feedback gain, Kgp, is adjusted to the upper limit, Lim.As described above, by setting the upper limit Lim for the deflection angular velocity feedback gain Kgp, the destabilization of the control due to the excessively high deflection angular velocity feedback gain Kgp can be effectively suppressed.

[0085] Even in the fifth embodiment, as described above, the same effect as in the first embodiment described above can be demonstrated.

[0086] Fig. Figure 13 shows a timing diagram illustrating an example of processing a setting of the deflection angular velocity feedback gain Kgp, which is carried out in a robot system according to a sixth embodiment.

[0087] The present embodiment is the same as the first embodiment described above, except that the method for adjusting the deflection angular velocity feedback gain Kgp differs. In the following description, the present embodiment is described with a focus on its differences from the first embodiment described above, and the description of identical items is not repeated. Additionally, in the drawings of the present embodiment, the same configurations as those of the embodiment described above are designated with the same reference numerals.

[0088] In the first step S2 for setting a feedback amplification of the present embodiment, the time dt differs between any two points selected from the angular acceleration increase start point N1s, the angular acceleration increase end point N1e, the angular acceleration decrease start point N2s, the angular acceleration decrease end point N2e, the angular acceleration increase start point N3s, the angular acceleration increase end point N3e, the angular acceleration decrease start point N4s and the angular acceleration decrease end point N4e.

[0089] In the Fig. In the 13 illustrated example, compared to the time dt at the angular acceleration increase start point N1s, the angular acceleration decrease start point N2s, the angular acceleration increase end point N3e, and the angular acceleration decrease end point N4e, the time dt is longer at the angular acceleration increase end point N1e and the angular acceleration decrease end point N2e, and conversely, the time dt is shorter at the angular acceleration increase start point N3s and the angular acceleration decrease start point N4s. Since the increasing time dt prolongs a state in which the displacement angular velocity feedback gain Kgp is high, the vibration suppression effect can be improved. On the other hand, shortening the time dt can suppress the wrapping of the oscillation in the non-rotational direction, as described above, and the destabilization of the control system can be effectively suppressed.Therefore, by setting the time dt for each angular acceleration change point, a balance can be struck between the vibration suppression effect and the destabilization of the control at each angular acceleration change point.

[0090] As described above, in the control method of the robot 2 of the present embodiment, in the first step S2 for setting a feedback amplification, the time dt differs as the predetermined time between any two time points selected from the angular acceleration increase start point N1s, which is the first time point T1, the angular acceleration increase end point N1e, which is the second time point T2, the angular acceleration decrease start point N2s, which is the third time point T3, the angular acceleration decrease end point N2e, which is the fourth time point T4, the angular acceleration increase start point N3s, which is the fifth time point T5, the angular acceleration increase end point N3e, which is the sixth time point T6, the angular acceleration decrease start point N4s, which is the seventh time point T7, and the angular acceleration decrease end point, which is the eighth time point T8.With such a method, a balance can be struck between the vibration suppression effect and the destabilization of the control system at any given time.

[0091] Even in the sixth embodiment, as described above, the same effect as in the first embodiment described above can be demonstrated.

[0092] Fig. Figure 14 shows a timing diagram illustrating an example of the processing of a setting of the deflection angular velocity feedback gain Kgp, which is carried out in a robot system according to a seventh embodiment.

[0093] The present embodiment is the same as the first embodiment described above, except that the method for adjusting the deflection angular velocity feedback gain Kgp differs. In the following description, the present embodiment is described with a focus on its differences from the first embodiment described above, and the description of identical items is not repeated. Additionally, in the drawings of the present embodiment, the same configurations as those of the embodiment described above are designated with the same reference numerals.

[0094] In the present embodiment, as in Fig. Figure 14 illustrates that if the setting of the deflection angular velocity feedback gain coefficient Kgpc is continued with the angular acceleration increase start point N1s as the starting point until the angular acceleration increase end point N1e, the setting of the deflection angular velocity feedback gain coefficient Kgpc is canceled with the angular acceleration increase end point N1e as the starting point. That is, if the setting of the deflection angular velocity feedback gain coefficient Kgpc is continued with a specific angular acceleration change point as the starting point until the next angular acceleration change point, the setting of the deflection angular velocity feedback gain coefficient Kgpc is canceled with the next angular acceleration change point as the starting point.With such processing, the adjustment of the deflection angular velocity feedback gain coefficient Kgpc can be performed continuously, thus suppressing an increase in the time required to increase the deflection angular velocity feedback gain Kgp. Therefore, control destabilization can be effectively suppressed.

[0095] Even in the seventh embodiment, as described above, the same effect as in the first embodiment described above can be demonstrated.

[0096] Fig. Figure 15 shows a timing diagram illustrating an example of processing a setting of the deflection angular velocity feedback gain Kgp, which is performed in a robot system according to an eighth embodiment.

[0097] The present embodiment is the same as the first embodiment described above, except that the method for adjusting the deflection angular velocity feedback gain Kgp differs. In the following description, the present embodiment is described with a focus on its differences from the first embodiment described above, and the description of identical items is not repeated. Additionally, in the drawings of the present embodiment, the same configurations as those of the embodiment described above are designated with the same reference numerals.

[0098] In Fig. In section 15, there is no section where the arm 22 operates at a constant speed. In this case, a point where the speed command Vref changes from an increase to a decrease corresponds to the angular acceleration decrease endpoint N2e and the angular acceleration increase start point N3s. In the present embodiment, the adjustment of the deflection angular velocity feedback gain coefficient Kgpc is not performed with the two points N2e and N3s as the starting points. This is because there is no increase in deflection oscillation due to no change in angular acceleration at points N2e and N3s, resulting in a low vibration suppression effect, which is achieved by adjusting the deflection angular velocity feedback gain Kgp.As described above, by not adjusting the deflection angular velocity feedback gain coefficient Kgpc at a point where the vibration suppression effect is low, control destabilization can be suppressed.

[0099] Even in the eighth embodiment, as described above, the same effect as in the first embodiment described above can be shown.

[0100] Fig. Figure 16 shows a timing diagram illustrating an example of the processing of a setting of the deflection angular velocity feedback gain Kgp, which is carried out in a robot system according to a ninth embodiment.

[0101] The present embodiment is the same as the first embodiment described above, except that the method for adjusting the deflection angular velocity feedback gain Kgp differs. In the following description, the present embodiment is described with a focus on its differences from the first embodiment described above, and the description of identical items is not repeated. Additionally, in the drawings of the present embodiment, the same configurations as those of the embodiment described above are designated with the same reference numerals.

[0102] In the present embodiment, the deflection angular velocity feedback gain coefficient Kgpc is set with a point at which the angular acceleration of the arm 22 exceeds a predetermined threshold, for example ±Ahys, as the starting point. In the Fig. In the illustrated example 16, the adjustment to increase the deflection angular velocity feedback gain coefficient Kgpc is performed at a point where the angular acceleration begins to increase from a constant state and exceeds the threshold. This threshold is reached at the times (the first time T1, the third time T3, the fifth time T5, and the seventh time T7) that are slightly delayed from the angular acceleration increase start point N1s, the angular acceleration decrease start point N2s, the angular acceleration increase start point N3s, and the angular acceleration decrease start point N4s, respectively. As a result, the oscillation of arm 22 can be suppressed more effectively.

[0103] In such processing, since the angular acceleration change point is detected, there is a risk of erroneous detection of the angular acceleration change point due to noise contained in the angular acceleration. In this respect, by providing a hysteresis property of ±Ahys for determining the angular acceleration change point, the erroneous detection of the angular acceleration change point can be suppressed. Additionally, in the present embodiment, the deflection angular velocity feedback gain coefficient Kgpc is set with a point at which the angular acceleration of arm 22 transitions from a changing state to a constant state as the starting point. In the Fig. In the 16 illustrated example, the adjustment to increase the deflection angular velocity feedback gain coefficient Kgpc is carried out with a point at which the angular acceleration transitions from a changing state to a constant state, that is, the time points (the second time T2, the fourth time T4, the sixth time T6 and the eighth time T8) that are slightly delayed from the angular acceleration increase endpoint N1e, the angular acceleration decrease endpoint N2e, the angular acceleration increase endpoint N3e and the angular acceleration decrease endpoint N4e, than the starting points.

[0104] As described above, in the control method of robot 2 of the present embodiment, the first time point T1, the third time point T3, the fifth time point T5, and the seventh time point T7 are the times at which the angular acceleration, which is the inertial information, exceeds the threshold value. As a result, the oscillation of arm 22 can be suppressed more effectively.

[0105] Even in the ninth embodiment, as described above, the same effect as in the first embodiment described above can be demonstrated.

[0106] Fig. Figure 17 shows a timing diagram illustrating an example of the processing of a setting of the deflection angular velocity feedback gain Kgp, which is carried out in a robot system according to a tenth embodiment.

[0107] The present embodiment is the same as the first embodiment described above, except that the method for adjusting the deflection angular velocity feedback gain Kgp differs. In the following description, the present embodiment is described with a focus on its differences from the first embodiment described above, and the description of identical items is not repeated. Additionally, in the drawings of the present embodiment, the same configurations as those of the embodiment described above are designated with the same reference numerals.

[0108] In the present embodiment, if the adjustment to increase the deflection angular velocity feedback gain Kgp is not performed, the deflection angular velocity feedback gain coefficient Kgpc is set to zero. That is, the reference value of the deflection angular velocity feedback gain coefficient Kgpc is set to zero. In the Fig. In the illustrated example 17, the angular velocity detection range of the inertial sensor 24 is limited to Vmax or less. For the angular acceleration increase start point N1s, the angular acceleration decrease end point N2e, the angular acceleration increase start point N3s, and the angular acceleration decrease end point N4e, where the angular velocity is Vmax or less, the setting to increase the deflection angular velocity feedback gain coefficient Kgpc is performed with each of the points as the starting point.On the other hand, for the angular acceleration increase endpoint N1e, the angular acceleration decrease start point N2s, the angular acceleration increase endpoint N3e, and the angular acceleration decrease start point N4s, where the angular velocity exceeds Vmax, the adjustment to increase the deflection angular velocity feedback gain coefficient Kgpc is not performed with each of these points as the starting point. With such processing, even if the inertial sensor 24 is used with an insufficient angular velocity detection range, a sufficient vibration suppression effect can be demonstrated.

[0109] Even in the tenth embodiment, as described above, the same effect as in the first embodiment described above can be demonstrated.

[0110] Fig. Figure 18 shows a timing diagram illustrating an example of the processing of a setting of the deflection angular velocity feedback gain Kgp, which is carried out in a robot system according to an eleventh embodiment.

[0111] The present embodiment is the same as the first embodiment described above, except that the method for adjusting the deflection angular velocity feedback gain Kgp differs. In the following description, the present embodiment is described with a focus on its differences from the first embodiment described above, and the description of identical items is not repeated. Additionally, in the drawings of the present embodiment, the same configurations as those of the embodiment described above are designated with the same reference numerals.

[0112] In the present embodiment, conditions for setting the deflection angular velocity feedback gain Kgp are switched between when the arm 22 performs point-to-point (PTP) actuation and when the arm 22 performs continuous displacement (CP) actuation. All of the embodiments described above describe when the arm 22 performs PTP actuation. On the other hand, illustrates Fig. 18 a change in angular acceleration when arm 22 performs the CP actuation. As from Fig. As can be seen in Figure 18, the angular acceleration changes continuously when the arm 22 performs CP actuation. This means there is an infinite number of continuous points of change in angular acceleration. In such a case, if the setting to increase the deflection angular velocity feedback gain coefficient Kgpc is performed in the same way as when the arm 22 performs PTP actuation, a state in which the deflection angular velocity feedback gain Kgp is high is continuously maintained, which can lead to control destabilization. Therefore, by switching the conditions for setting the deflection angular velocity feedback gain Kgp between CP actuation and PTP actuation, the control destabilization during CP actuation can be suppressed, and the vibration suppression effect can be maintained.

[0113] As described above, in the control procedure of robot 2 of the present embodiment, the conditions for setting the deflection angular velocity feedback gain Kgp are varied in the first step S2 to adjust the feedback gain, between when arm 22 performs the CP actuation and when arm 22 performs the PTP actuation. As a result, the destabilization of the control during CP actuation can be suppressed, and the vibration suppression effect can be maintained.

[0114] Even in the eleventh embodiment, as described above, the same effect as in the first embodiment described above can be demonstrated.

[0115] Fig. Figure 19 shows a diagram illustrating a robot provided in a robot system according to a twelfth embodiment. Fig. Figure 20 shows a block diagram illustrating a control system used in the robot system of Fig. 19 is provided. Fig. Figure 21 shows a diagram illustrating a two-inertia system model of a linear motion section of the robot. Fig. Figure 22 shows a diagram illustrating changes in an acceleration command Aref', a velocity V1 and a velocity V2 during an actuation of a splined shaft. Fig. Figure 23 shows a time diagram illustrating an example of the processing of a setting of the deflection angular velocity feedback gain Kgp. Fig. Figure 24 shows a diagram illustrating a residual vibration suppression effect of the splined shaft.

[0116] The present embodiment is the same as the first embodiment described above, except that the configuration of robot 2 is different. In the following description, the present embodiment is described with a focus on the differences from the first embodiment described above, and the description of identical items is not repeated. Additionally, in each of the drawings of the present embodiment, the identical configurations as those of the embodiment described above are designated with the same reference numerals.

[0117] As in Fig. As illustrated in Figure 19, the robot 2 further includes a splined shaft 253 as a motion section, which is arranged at the tip end section of the arm 22, and a ball screw nut 252. When the ball screw nut 252 rotates, the splined shaft 253 is raised and lowered along a central axis Jg of the splined shaft 253. An end effector suitable for an intended operation is mounted at the tip end section (lower end section) of the splined shaft 253.

[0118] Furthermore, the robot 2 also includes a drive mechanism 27 that rotates the ball screw nut 252 to raise and lower the splined shaft 253. The drive mechanism 27 includes a motor 271, a position detector 272 that detects the rotation angle of a rotating shaft of the motor 271, and a power transmission mechanism 273 that transmits power from the motor 271 to the ball screw nut 252. The power transmission mechanism 273 includes a pulley 273a mounted on the rotating shaft of the motor 271 and a toothed belt 273b wound around the pulley 273a and the ball screw nut 252. In reality, a splined nut and a drive mechanism that rotates the splined nut to rotate the splined shaft 253 about the central axis Jg are provided. However, since this is not closely related to the present embodiment, its description and illustration are omitted.

[0119] Furthermore, the inertial sensor 24 attached to the arm 22 is an angular velocity sensor that detects an angular velocity about a detection axis Js that is orthogonal to an extension direction of the arm 22 and the central axis Jg.

[0120] The control device 3 is further described as follows.

[0121] In the Fig. In the illustrated control unit 30, the deflection angular velocity feedback generation unit 35 first receives a deflection angular velocity 932 by multiplying an angular velocity 931 of the arm 22, detected by the inertial sensor 24, by the arm angular velocity scaling coefficient Kgs. Next, the deflection angular velocity feedback generation unit 35 receives a deflection angular velocity feedback 933 by multiplying the deflection angular velocity 932 by the deflection angular velocity feedback gain Kgp (the deflection angular velocity feedback base gain Kgpb and the deflection angular velocity feedback feedback gain coefficient Kgpc).

[0122] The position command generation unit 31 generates a position command 921 for the motor 271 based on the program created by the host computer 4.

[0123] The position control unit 32 first receives a position deviation 923, which is obtained by subtracting a motor shaft position 922, which is the rotation angle of the motor 271 detected by the position detector 272, from the position command 921. Next, the position control unit 32 receives a speed command 924 by multiplying the position deviation 923 by the position loop proportional gain Kpp.

[0124] The speed control unit 33 is configured with proportional-integral control. The speed control unit 33 first receives a motor shaft angular velocity 925, which is the angular velocity of the motor shaft, by differentiating the motor shaft position 922 over time, which is detected by the position detector 272. Next, the speed control unit 33 receives a speed deviation 926, which is obtained by subtracting the motor shaft angular velocity 925 from the speed command 924.Next, the speed control unit 33 receives a current command 927 by adding an integral term, obtained by multiplying an integral value of the speed deviation 926 with the speed loop integral gain Kvi, to a proportional term, obtained by multiplying the speed deviation 926 with the speed loop proportional gain Kvp, and further subtracting the deflection angular velocity feedback 933.

[0125] The current control unit 34 controls a current 928 to drive the motor 271 in accordance with the current command 927; that is, it controls the current 928 to follow the current command 927. The motor 271 is driven by the current 928, which is controlled by the current control unit 34, and a load 28 coupled to the motor 271 moves linearly. Here, the load 28 is mainly the sum of the inertial masses of the motor shaft, the drive mechanism 27, the ball screw nut 252, and the splined shaft 253.

[0126] The circuit configuration of controller 30 is briefly described above. Next, it is illustrated... Fig. 21 a two-inertia system model 700 of the linear motion section of the robot 2. In such a two-inertia system model 700, a drive element 702, having an inertial mass m2, is arranged on a base element 701, having an inertial mass m1, and the base element 701 is coupled to an installation surface via a spring element 703, having a spring constant Ks. The inertia sensor 24 is arranged on the base element 701 and detects the velocity V1 of the base element 701 in an x1 direction.

[0127] In robot 2, the spring element 703 primarily corresponds to the stiffness of the vertical displacement (displacement in the direction along the axis of rotation J) of the base 21 and the arm 22. Furthermore, in robot 2, the base element 701 is primarily configured with the base 21 and the arm 22. Additionally, in robot 2, the drive element 702 is primarily configured with the splined shaft 253. When the drive element 702 is operating, a reaction force acts on the base element 701, which supports the drive element 702, and the base element 701 is displaced. A thrust force Fs, proportional to the displacement of the spring element 703, acts on the base element 701.

[0128] The main cause of the vibration of the tip end section of the splined shaft 253 in the direction along the central axis Jg is the vibration of the tip end section of the arm 22. In this respect, by using the deflection angular velocity feedback 933, which is obtained by multiplying the deflection angular velocity 932, which is detected by the inertial sensor 24, by the deflection angular velocity feedback gain Kgp, the vibration of the arm 22 can be damped for the control of the motor 271 by using the reaction force to drive the splined shaft 253.

[0129] Fig. Figure 22 illustrates changes in the acceleration command Aref', the velocity V2 of the drive element 702, and the velocity V1 of the base element 701 during the point-to-point (PTP) actuation of the arm 22. As shown in Fig. Figure 22 illustrates that the acceleration command Aref' changes at the start of acceleration if the acceleration increase point is N1s' and the acceleration increase endpoint is N1e'; at the end of acceleration if the acceleration decrease point is N2s' and the acceleration decrease endpoint is N2e'; at the start of deceleration if the acceleration increase point is N3s' and the acceleration increase endpoint is N3e'; and at the end of deceleration if the acceleration decrease point is N4s' and the acceleration decrease endpoint is N4e'. Additionally, there is a constant-velocity section between the acceleration decrease endpoint N2e' and the acceleration increase start point N3s'.

[0130] The oscillation of velocity V1 (hereinafter also referred to as "displacement oscillation") increases with each acceleration change point, where the acceleration command Aref' changes, i.e., the acceleration increase start point N1s', the acceleration increase end point N1e', the acceleration decrease start point N2s', the acceleration decrease end point N2e', the acceleration increase start point N3s', the acceleration increase end point N3e', the acceleration decrease start point N4s', and the acceleration decrease end point N4e'. This is a phenomenon that occurs when the reaction force caused by the acceleration and deceleration of the drive element 702 acts on the base element 701.

[0131] In this context, in the robot system 1, the deflection angular velocity feedback gain Kgp is increased at a time determined based on each of the eight points N1s', N1e', N2s', N2e', N3s', N3e', N4s' and N4e' described above, where the deflection oscillation of velocity V1 increases, thereby reducing the oscillation of the base element 701, i.e., the arm 22.

[0132] In particular, the deflection angular velocity feedback gain Kgp is increased with a first time T1', which is determined based on the acceleration increase start point N1s', a second time T2', which is determined based on the acceleration increase end point N1e', a third time T3', which is determined based on the acceleration decrease start point N2s', a fourth time T4', which is determined based on the acceleration decrease end point N2e', a fifth time T5', which is determined based on the acceleration increase start point N3s', a sixth time T6', which is determined based on the acceleration increase end point N3e', a seventh time T7', which is determined based on the acceleration decrease start point N4s', and an eighth time T8', which is determined based on the acceleration decrease end point N4e', as the starting points,which reduces the vibration of arm 22.

[0133] In the present embodiment, the first time point T1' is set to the same time point as the acceleration increase start point N1s', the second time point T2' is set to the same time point as the acceleration increase end point N1e', the third time point T3' is set to the same time point as the acceleration decrease start point N2s', the fourth time point T4' is set to the same time point as the acceleration decrease end point N2e', the fifth time point T5' is set to the same time point as the acceleration increase start point N3s', the sixth time point T6' is set to the same time point as the acceleration increase end point N3e', the seventh time point T7' is set to the same time point as the acceleration decrease start point N4s', and the eighth time point T8' is set to the same time point as the acceleration decrease end point N4e'.As a result, the deflection angular velocity feedback gain Kgp can be increased without delay for each of the acceleration change points: the acceleration increase start point N1s', the acceleration increase end point N1e', the acceleration decrease start point N2s', the acceleration decrease end point N2e', the acceleration increase start point N3s', the acceleration increase end point N3e', the acceleration decrease start point N4s' and the acceleration decrease end point N4e', thereby obtaining a higher vibration suppression effect.

[0134] However, the present disclosure is not limited to this, and, for example, the first time point T1' can be a time point that is later than the acceleration increase starting point N1s' by the predetermined time Δt, or it can be a time point that is earlier than the acceleration increase starting point N1s' by the predetermined time Δt. The same applies to the second, third, fourth, fifth, sixth, seventh, and eighth times point T2', T3', T4', T5', T6', T7', and T8', which differ from the first time point T1'. In addition, the predetermined time Δt can differ between two or more times point in time that are optionally selected from the first, second, third, fourth, fifth, sixth, seventh, and eighth times point T1', T2', T3', T4', T5', T6', T7', and T8'.

[0135] For the sake of simplicity, the first time point T1' is described as the acceleration increase starting point N1s', the second time point T2' is described as the acceleration increase end point N1e', the third time point T3' is described as the acceleration decrease starting point N2s', the fourth time point T4' is described as the acceleration decrease end point N2e', the fifth time point T5' is described as the acceleration increase starting point N3s', the sixth time point T6 is described as the acceleration increase end point N3e', the seventh time point T7' is described as the acceleration decrease starting point N4s', and the eighth time point T8' is described as the acceleration decrease end point N4e'.

[0136] Here, destabilization factors of the control system that can occur due to an increase in the deflection angular velocity feedback gain Kgp are considered, for example, (A) a destabilization of the physical control system due to elements forming a drive system, and (B) a reduced control stability due to the wrapping of oscillations in directions other than a linear direction of motion. Destabilization factor (A) refers to a destabilization of the deflection angular velocity feedback control system, which is determined by the inertial mass m2 of the drive element 702, the inertial mass m1 of the base element 701, and the spring constant Ks in the two-inertia system model 700.Meanwhile, the destabilization factor (B) refers to a destabilization of the deflection angular velocity feedback control that occurs when the arm 22 oscillates in directions different from the linear direction of motion of the splined shaft 253 due to the elastic deformation of each element forming the robot 2. The inertial sensor 24 detects the oscillation (hereinafter also referred to as "oscillation in a non-linear direction of motion") as noise, and the controller 30 uses the noise for control. The oscillation in the non-linear direction of motion occurs due to the wrapping of the deflection oscillation in the linear direction of motion. Therefore, the oscillation in the non-linear direction of motion increases with a delay relative to the deflection oscillation in the linear direction of motion.

[0137] In this respect, in robot system 1, by using the property that the oscillation in the non-linear direction of motion increases with a delay relative to the displacement oscillation in the linear direction of motion, the displacement angular velocity feedback gain Kgp is temporarily increased with the eight acceleration change points described above, at which the displacement oscillation in the linear direction increases, that is, the acceleration increase start point N1s', the acceleration increase end point N1e', the acceleration decrease start point N2s', the acceleration decrease end point N2e', the acceleration increase start point N3s', the acceleration increase end point N3e', the acceleration decrease start point N4s' and the acceleration decrease end point N4e', as the starting points to dampen the displacement oscillation in the linear direction of motion.This suppresses the destabilization of the control system due to the amplification of the oscillation in the non-linear direction of motion. As described above, by temporarily increasing the deflection angular velocity feedback gain Kgp, the deflection angular velocity feedback gain Kgp can be reduced again when the oscillation in the non-linear direction of motion increases, thereby reducing or preferably eliminating the influence of the destabilization factor (B).

[0138] In the prior art, due to the destabilization factor (B), the deflection angular velocity feedback gain Kgp cannot be increased to a limit (maximum value) of the destabilization factor (A). On the other hand, with the control method of the present embodiment as described above, the influence of the destabilization factor (B) is reduced, so that the deflection angular velocity feedback gain Kgp can be increased to the limit of the destabilization factor (A). Therefore, the deflection angular velocity feedback gain Kgp can be set higher than in the prior art without destabilizing the control system, and the vibration suppression effect of the arm 22 can be improved.

[0139] Fig. Figure 23 shows a time diagram illustrating an example of processing a setting of the deflection angular velocity feedback gain Kgp with the eight points described above, which are the change points of the acceleration command Aref', that is, the acceleration increase start point N1s', the acceleration increase end point N1e', the acceleration decrease start point N2s', the acceleration decrease end point N2e', the acceleration increase start point N3s', the acceleration increase end point N3e', the acceleration decrease start point N4s' and the acceleration decrease end point N4e', as the starting points. Fig. Figure 23 illustrates changes to the acceleration command Aref', a velocity command Vref', and the deflection angular velocity feedback gain coefficient Kgpc.

[0140] In the illustrated example, the displacement angular velocity feedback gain coefficient Kgpc is increased from 1, which is the reference value, to 3 for dt seconds with all points—the acceleration increase start point N1s', the acceleration increase end point N1e', the acceleration decrease start point N2s', the acceleration decrease end point N2e', the acceleration increase start point N3s', the acceleration increase end point N3e', the acceleration decrease start point N4s', and the acceleration decrease end point N4e'—as the starting points. The displacement angular velocity feedback gain coefficient Kgpc is increased from 1 to 3 and then decreased from 3 to 1, i.e., back to the reference value, after dt seconds have elapsed.Therefore, the controller 30 controls the drive of the motor 271 using the deflection angular velocity feedback gain coefficient Kgpc = 3, until the deflection angular velocity feedback gain coefficient Kgpc is increased from 1 to 3 and then decreased back to 1, and controls the drive of the motor 271 using the deflection angular velocity feedback gain coefficient Kgpc = 1 at other times.

[0141] The deflection angular velocity feedback gain Kgp is obtained by multiplying the deflection angular velocity feedback base gain Kgpb by the deflection angular velocity feedback gain coefficient Kgpc, as shown in equation (2) above. Therefore, increasing the deflection angular velocity feedback gain coefficient Kgpc to 3 increases the deflection angular velocity feedback gain Kgp by a factor of three.By increasing the displacement angular velocity feedback gain Kgp by three times, the effect of damping the displacement oscillation is increased, and it is possible to reduce the displacement oscillation that increases during operation with each of the acceleration change points: the acceleration increase start point N1s', the acceleration increase end point N1e', the acceleration decrease start point N2s', the acceleration decrease end point N2e', the acceleration increase start point N3s' and the acceleration increase end point N3e', as the start points, and the residual oscillation that increases after stopping with each of the acceleration change points: the acceleration decrease start point N4s' and the acceleration decrease end point N4e', as the start points.

[0142] Adjusting the deflection angular velocity feedback gain coefficient Kgpc at the acceleration increase start point N1s' and the acceleration increase end point N1e' reduces the deflection oscillation of the splined shaft 253 during acceleration operation. Similarly, adjusting the deflection angular velocity feedback gain coefficient Kgpc at the acceleration decrease start point N2s' and the acceleration decrease end point N2e' reduces the deflection oscillation of the splined shaft 253 during constant-speed operation. Furthermore, adjusting the deflection angular velocity feedback gain coefficient Kgpc at the acceleration increase start point N3s' and the acceleration increase end point N3e' reduces the deflection oscillation of the splined shaft 253 during deceleration operation.Furthermore, adjusting the deflection angular velocity feedback gain coefficient Kgpc at the acceleration decrease start point N4s' and the acceleration decrease end point N4e' has the effect of reducing the residual vibration of the splined shaft 253.

[0143] In the illustrated example, the displacement angular velocity feedback gain coefficient Kgpc is increased from 1 to 3 with all points—the acceleration increase start point N1s', the acceleration increase end point N1e', the acceleration decrease start point N2s', the acceleration decrease end point N2e', the acceleration increase start point N3s', the acceleration increase end point N3e', the acceleration decrease start point N4s', and the acceleration decrease end point N4e'—as the starting points. However, the present disclosure is not limited to this, and the displacement angular velocity feedback gain coefficient Kgpc only needs to be increased from 1 to 3 with at least one of the eight points as the starting point. Consequently, at least the displacement oscillation that increases with the point as the starting point can be effectively suppressed.Additionally, in the illustrated example, the deflection angular velocity feedback gain coefficient Kgpc is increased to 3, but the value of the deflection angular velocity feedback gain coefficient Kgpc is not particularly limited.

[0144] Fig. Figure 24 shows a diagram illustrating the residual vibration suppression effect of the tip end section of the splined shaft 253 and comparing the residual vibration in the linear motion direction occurring in the tip end section of the splined shaft 253 between C, where the deflection angular velocity feedback gain Kgp is kept constant, and D, where the deflection angular velocity feedback gain Kgp is changed synchronously with the acceleration change as in the present embodiment. It can be seen from Fig. 24 can be seen that the overshoot is reduced in the present embodiment, and an excellent vibration suppression effect is shown.

[0145] As described above, in the present embodiment of the robot system 1, the splined shaft 253 is the motion section that moves linearly along a predetermined operating direction with respect to the arm 22. Additionally, the inertial sensor 24 detects the angular velocity about the detection axis Js, which is orthogonal to the operating direction of the splined shaft 253. This angular velocity is caused by the elastic deformation of the arm 22. Furthermore, the controller 30 obtains the deflection angular velocity 932 based on the angular velocity of the arm 22 detected by the inertial sensor 24 and multiplies the deflection angular velocity 932 by the deflection angular velocity feedback gain Kgp. By using the deflection angular velocity feedback 933 obtained in this way, the vibration suppression effect of the splined shaft 253 can be improved.

[0146] Even in the twelfth embodiment, as described above, the same effect as in the first embodiment described above can be demonstrated.

[0147] In the present embodiment, the processing of an adjustment of the deflection angular velocity feedback gain Kgp is the same as the processing of the first embodiment described above, but the present disclosure is not limited thereto, and the processing method described in the second to eleventh embodiments described above can also be applied. As a result, the same effects as those described in each of the embodiments can be shown.

[0148] Fig. Figure 25 shows a diagram illustrating a robot provided in a robot system according to a thirteenth embodiment.

[0149] The present embodiment is the same as the first embodiment described above, except that the robot configuration differs. In the following description, the present embodiment is described with a focus on the differences from the first embodiment described above, and the description of identical items is not repeated. Additionally, in the drawings of the present embodiment, the same configurations as those of the embodiment described above are designated with the same reference numerals.

[0150] As in Fig. As illustrated in Figure 25, a robot 2100 of the present embodiment is a horizontally articulated robot (SCARA robot) and includes a base 2110 which is attached to the floor and an arm 2120 which is coupled to the base 2110. Furthermore, the arm 2120 includes a first arm 2121, which includes a base end section coupled to the base 2110 and which rotates about a first axis of rotation J1 with respect to the base 2110, and a second arm 2122, which includes a base end section coupled to a tip end section of the first arm 2121 and which rotates about a second axis of rotation J2 parallel to the first axis of rotation J1 with respect to the first arm 2121. An inertial sensor 2190, which detects an angular velocity about an axis along the vertical direction and an angular velocity about an axis orthogonal to the vertical direction, is arranged on the second arm 2122.

[0151] Furthermore, a working head 2130 is provided at the tip end section of the second arm 2122. The working head 2130 includes a wedge nut 2131 and a ball screw nut 2132, which are arranged coaxially at the tip end section of the second arm 2122, and a splined shaft 2133, which is inserted through the wedge nut 2131 and the ball screw nut 2132. The splined shaft 2133 rotates about a third axis of rotation J3, which is a central axis of the splined shaft 2133 with respect to the second arm 2122, and is raised and lowered along the third axis of rotation J3. An end effector suitable for the work is mounted at a lower end section (tip end section) of the splined shaft 2133. The third axis of rotation J3 is parallel to the first axis of rotation J1 and the second axis of rotation J2 and extends along the vertical direction.

[0152] Furthermore, the robot 2100 includes a drive mechanism 2140, which rotates the first arm 2121 about the first axis of rotation J1 relative to the base 2110, and a drive mechanism 2150, which rotates the second arm 2122 about the second axis of rotation J2 relative to the first arm 2121. The drive mechanism 2140 and the drive mechanism 2150 have the same configuration as the drive mechanism 23 described above. That is, the drive mechanism 2140 includes a reduction gear 2141, which couples the base 2110 and the first arm 2121, a motor 2142, which includes a rotating shaft coupled to an input side of the reduction gear 2141, and a position detector 2143, which detects the rotation angle of the rotating shaft of the motor 2142.Likewise, the drive mechanism 2150 includes a reduction gear 2151 that couples the first arm 2121 and the second arm 2122, a motor 2152 which includes a rotating shaft that is coupled to an input side of the reduction gear 2151, and a position detector 2153 that detects a rotation angle of the rotating shaft of the motor 2152.

[0153] Furthermore, the robot 2100 includes a drive device 2160, which rotates the wedge nut 2131 to rotate the splined shaft 2133 about the third axis of rotation J3, and a drive device 2170, which rotates the ball screw nut 2132 to raise and lower the splined shaft 2133 along the third axis of rotation J3. The drive devices 2160 and 2170 have the same configuration as the drive mechanism 27 described above. That is, the drive device 2160 includes a motor 2161, a position detector 2162, which detects a rotation angle of a rotating shaft of the motor 2161, and a power transmission mechanism 2163, which transmits power from the motor 2161 to the wedge nut 2131.Likewise, the drive device 2170 includes a motor 2171, a position detector 2172 that detects a rotation angle of a rotating shaft of the motor 2171, and a power transmission mechanism 2173 that transmits power from the motor 2171 to the ball screw nut 2132.

[0154] In the robot 2100 with the configuration as described above, the vibrations of the first and second arms 2121 and 2122 can be effectively suppressed by using the control method of the first to eleventh embodiments described above to control the motors 2142 and 2152 to drive the first and second arms 2121 and 2122.

[0155] The deflection angular velocity 914 of the first arm 2121 can be obtained by subtracting the motor shaft angular velocity 913 of the motor 2152, which drives the second arm 2122, and the motor shaft angular velocity 913 of the motor 2142, which drives the first arm 2121, from the angular velocity detected by the inertial sensor 2190.

[0156] Furthermore, the deflection angular velocity 914 of the second arm 2122 can be obtained by subtracting the motor shaft angular velocity 913 of the motor 2142, which drives the first arm 2121, and the motor shaft angular velocity 913 of the motor 2152, which drives the second arm 2122, from the angular velocity detected by the inertial sensor 2190.

[0157] Furthermore, in the robot 2100 with the configuration as described above, the control method of the twelfth embodiment described above can also be used to control the motor 2171 to raise and lower the splined shaft 2133 along the third rotary axis J3.

[0158] With such a configuration, the vibration of the tip end section of the splined shaft 2133 can be effectively suppressed.

[0159] Even in the thirteenth embodiment, as described above, the same effect as in the first embodiment described above can be demonstrated.

[0160] Fig. Figure 26 shows a diagram illustrating a robot provided in a robot system according to a fourteenth embodiment.

[0161] The present embodiment is the same as the first embodiment described above, except that the robot configuration differs. In the following description, the present embodiment is described with a focus on the differences from the first embodiment described above, and the description of identical items is not repeated. Additionally, in the drawings of the present embodiment, the same configurations as those of the embodiment described above are designated with the same reference numerals.

[0162] As in Fig.As illustrated in Figure 26, a robot 2200 of the present embodiment is a six-axis vertically articulated robot comprising six drive axes and a base 2210 attached to the floor, and an arm 2220 coupled to the base 2210 to be rotatable. Furthermore, the arm 2220 is configured such that a first arm 2221, a second arm 2222, a third arm 2223, a fourth arm 2224, a fifth arm 2225, and a sixth arm 2226 are coupled to one side of the base 2210 to be rotatable. An end effector suitable for the task is mounted on the sixth arm 2226.

[0163] Furthermore, the robot 2200 includes a drive mechanism 2231 that rotates the first arm 2221 about a first rotational axis J21 relative to the base 2210, a drive mechanism 2232 that rotates the second arm 2222 about a second rotational axis J22 relative to the first arm 2221, a drive mechanism 2233 that rotates the third arm 2223 about a third rotational axis J23 relative to the second arm 2222, a drive mechanism 2234 that rotates the fourth arm 2224 about a fourth rotational axis J24 relative to the third arm 2223, a drive mechanism 2235 that rotates the fifth arm 2225 about a fifth rotational axis J25 relative to the fourth arm 2224, and a drive mechanism 2236 that rotates the sixth arm 2226 about a sixth axis of rotation J26 rotates in relation to the fifth arm 2225.

[0164] Although not illustrated, each of the drive mechanisms 2231, 2232, 2233, 2234, 2235 and 2236 has the same configuration as that of the drive mechanism 23 described above and includes a reduction gear, a motor which includes a rotating shaft coupled to an input side of the reduction gear, and a position detector which detects a rotation angle of the rotating shaft of the motor.

[0165] Additionally, the robot 2200 also includes an inertial sensor 2241, which is located on the first arm 2221, and an inertial sensor 2242, which is located on the third arm 2223. The inertial sensor 2241 detects the angular velocity of the first arm 2221 about the first axis of rotation J21. The inertial sensor 2242 detects a combined angular velocity of the second arm 2222 about the second axis of rotation J22 and of the third arm 2223 about the third axis of rotation J23.

[0166] In the robot 2200 with the configuration as described above, the vibrations of the first and second arms 2221 and 2222 can be effectively suppressed by using the control method of the first to eleventh embodiments described above to control the motors for driving the first and second arms 2221 and 2222.

[0167] The deflection angular velocity 914 of the first arm 2221 can be obtained by subtracting the motor shaft angular velocity 913 of the motor driving the first arm 2221 from the angular velocity detected by the inertial sensor 2241. As a result, the vibration of the first arm 2221 can be effectively suppressed.

[0168] Furthermore, the deflection angular velocity 914 of the second arm 2222 can be obtained by subtracting the motor shaft angular velocity 913 of the motor driving the third arm 2223 and the motor shaft angular velocity 913 of the motor driving the second arm 2222 from the angular velocity detected by the inertial sensor 2242.

[0169] Furthermore, the deflection angular velocity 914 of the third arm 2223 can be obtained by subtracting the motor shaft angular velocity 913 of the motor driving the second arm 2222 and the motor shaft angular velocity 913 of the motor driving the third arm 2223 from the angular velocity detected by the inertial sensor 2242.

[0170] With such a configuration, the vibration of the tip end section of the arm 2220, i.e. the sixth arm 2226, can be effectively suppressed.

[0171] Even in the fourteenth embodiment, as described above, the same effect as in the first embodiment described above can be shown.

[0172] The thirteenth embodiment described above describes an application example for the horizontal-jointed robot, and the fourteenth embodiment describes an application example for the six-axis vertical-jointed robot, but the present disclosure is not limited thereto. For example, the present disclosure can be applied to an orthogonal-type robot or a seven-axis vertical-jointed robot. The present disclosure can be applied to any robot that includes at least one rotary joint or one linear joint.

[0173] As described above, the robot control method and the robot system of the present disclosure are described on the basis of the illustrated embodiments.

Claims

[1] Control procedures for a robot, including: an inertial information reception step (S1) of receiving an output signal from an inertial sensor (24) that measures an actuation of an arm (22); a first step (S2) for adjusting a feedback gain, in which an adjustment is made to increase a feedback gain to be multiplied by the output signal or a signal generated from the output signal, according to a change in the actuation of the arm (22); a drive control step (S3) of controlling a drive of the arm (22) using the feedback gain increased in the first step (S2) to set a feedback gain; and a second step (S4) for adjusting a feedback gain, in which an adjustment is made to decrease the feedback gain after a predetermined time has elapsed since the first step (S2) for adjusting a feedback gain. [2] Control method of a robot according to claim 1, wherein In the first step (S2) of setting a feedback gain, the feedback gain is changed from a reference value to a value that is higher than the reference value, and In the second step (S4) of setting a feedback gain, the feedback gain is reset to the reference value. [3] Control method of a robot according to claim 1, wherein the output signal contains inertial information, which is information regarding the inertia generated in the arm (22) by the actuation, and The first step (S2) to adjust feedback gain is performed on at least one of the following: a first time point (T1, T1') at which an increase in inertial information begins at the start of the acceleration of the arm, a second time point (T2, T2') at which the increase in inertial information ends at the start of the acceleration of the arm, a third time point (T3, T3') at which a decrease in inertial information begins at one end of the acceleration of the arm, a fourth time point (T4, T4') at which the decrease in inertial information ends at the end of the acceleration of the arm, a fifth time point (T5, T5') at which the increase in inertial information begins at the start of the slowing of the arm, a sixth time point (T6, T6') at which the increase in inertial information ends at the beginning of the slowing of the arm, a seventh time point (T7, T7') at which the decrease in inertial information begins at the end of the slowing of the arm, and an eighth time point (T8, T8') at which the decrease in inertial information ends with the end of the slowing down of the arm. [4] Control method of a robot according to claim 1, wherein The feedback gain is obtained by multiplying a feedback base gain, which is a reference for the feedback gain, by a feedback coefficient, and In the first step (S2) to set a feedback gain and in the second step (S4) to set a feedback gain, the feedback gain is set by changing the feedback coefficient. [5] Control method of a robot according to claim 3, wherein in the first step (S2) to adjust a feedback gain the feedback gain is adjusted such that it differs between any two time points selected from the first time point (T1, T1'), the second time point (T2, T2'), the third time point (T3, T3'), the fourth time point (T4, T4'), the fifth time point (T5, T5'), the sixth time point (T6, T6'), the seventh time point (T7, T7') and the eighth time point (T8, T8'). [6] Control method of a robot according to claim 3, wherein in the first step (S2) for setting a feedback gain the predetermined time differs between any two time points selected from the first time point (T1, T1'), the second time point (T2, T2'), the third time point (T3, T3'), the fourth time point (T4, T4'), the fifth time point (T5, T5'), the sixth time point (T6, T6'), the seventh time point (T7, T7') and the eighth time point (T8, T8'). [7] Control method of a robot according to claim 1, wherein the change in inertial information is detected based on a position command for the arm (22). [8] Control method of a robot according to claim 3, wherein the first time point (T1), the third time point (T3), the fifth time point (T5) and the seventh time point (T7) are times at which the inertial information exceeds a threshold. [9] Control method of a robot according to claim 1, wherein in the first step (S2) for setting a feedback gain conditions for setting the feedback gain are varied between when the arm (22) performs a CP actuation and when the arm (22) performs a PTP actuation. [10] Robot system (1), comprising: a base (21); an arm (22) which is driven in relation to the base (21); an inertial sensor (24) that detects an actuation of the arm (22); and a controller (30) that controls the drive of the arm (22), wherein the controller (30) receives an output signal from the inertial sensor (24), an adjustment is made to increase a feedback gain that is to be multiplied by the output signal or a signal generated from the output signal, according to a change in the actuation of the arm (22), controls the drive of the arm (22) using the feedback amplification after the setting, and performs an adjustment to decrease the feedback gain after a predetermined time has elapsed since the increase in feedback gain. [11] Robot system (1) according to claim 10, further comprising: a motor (232) that rotates the arm (22) about an axis of rotation relative to the base (21); and a position detector (233) that detects a rotation angle of the motor (232), wherein the controller (30) obtains a deflection angular velocity based on an angular velocity of the arm (22) about the axis of rotation, which is detected by the inertial sensor (24), and an angular velocity of the motor (232), which is detected by the position detector (233), and multiplies the deflection angular velocity by the feedback gain. [12] Robot system (1) according to claim 10, further comprising: a movement segment that moves linearly along a predetermined operating direction with respect to the arm (22), wherein the inertial sensor (24) detects an angular velocity in a direction orthogonal to the operating direction of the motion section, the angular velocity being caused by elastic deformation of the arm (22), and The controller (30) receives a deflection angular velocity based on an angular velocity of the arm (22) detected by the inertial sensor (24) and multiplies the deflection angular velocity by the feedback gain.

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