JP2024029677A - Robot control method, robot control program, and robot system - Google Patents

Abstract

An object of the present invention is to provide a robot control method, a robot control program, and a robot system that can perform excellent position control. A control method for a robot includes an arm and a motor for rotating the arm, and drives the motor based on a position command, the robot having an angular velocity sensor disposed on the arm. The drive of the motor is controlled based on the difference between a first position of the motor determined from the output of the motor and a second position of the motor determined from the output of a position detector connected to the motor. [Selection diagram] Figure 4

Description

The present invention relates to a robot control method, a robot control program, and a robot system.

The robot system described in Patent Document 1 includes a robot, a sensor, and a robot control device having an operation control section and a learning control section. The robot has six joint shafts, an arm connected by the joint shafts, and a servo motor that drives each joint shaft. The learning control unit calculates a vibration correction amount to correct vibrations that occur in the robot when the movement control unit operates the robot based on a movement command, and applies the calculated vibration correction amount to the next movement command. performs learning control.

Japanese Patent Application Publication No. 2018-130800

However, in a robot system such as that disclosed in Patent Document 1, the position of the robot that actually moves may deviate from the commanded target position due to structural deviations of the joint axes.

A method for controlling a robot according to the present invention is a method for controlling a robot comprising an arm and a motor for rotating the arm, and driving the motor based on a position command, the method comprising:
Based on the difference between a first position of the motor determined from the output of an angular velocity sensor disposed on the arm and a second position of the motor determined from the output of a position detector connected to the motor. Controlling the drive of the motor.

A control program for a robot according to the present invention is a control program for a robot that includes an arm and a motor that rotates the arm, and that drives the motor based on a position command,
Based on the difference between a first position of the motor determined from the output of an angular velocity sensor disposed on the arm and a second position of the motor determined from the output of a position detector connected to the motor. Controlling the drive of the motor.

The robot system of the present invention includes an arm, a motor for rotating the arm, an angular velocity sensor disposed on the arm, and a position detector connected to the motor and detecting the position of the motor. and,
a control device that controls driving of the motor;
The control device controls driving of the motor based on a difference between a first position of the motor determined from the output of the angular velocity sensor and a second position of the motor determined from the output of the position detector. .

1 is an overall diagram of a robot system according to a preferred embodiment. It is a longitudinal cross-sectional view of a 1st joint actuator. FIG. 2 is a block diagram showing a conventional motor control method. FIG. 2 is a block diagram showing a method of controlling a motor according to the present embodiment. It is a flowchart which shows the process of processing the signal of an angular velocity sensor.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a robot control method, a robot control program, and a robot system according to the present invention will be described in detail based on embodiments shown in the accompanying drawings.

FIG. 1 is an overall diagram of a robot system according to a preferred embodiment. FIG. 2 is a longitudinal sectional view of the first joint actuator. FIG. 3 is a block diagram showing a conventional motor control method. FIG. 4 is a block diagram showing the motor control method of this embodiment. FIG. 5 is a flowchart showing the process of processing the signal of the angular velocity sensor. Note that the vertical direction in FIGS. 1 and 2 corresponds to the vertical direction, and the upper side in FIGS. 1 and 2 is also referred to as "upper" and the lower side is also referred to as "lower".

The robot system 1 shown in FIG. 1 includes a robot 2 and a control device 9 that controls driving of the robot 2.

The robot 2 is a SCARA robot, and is used, for example, in various operations such as holding, transporting, assembling, and inspecting workpieces such as electronic components. However, the use of the robot 2 is not particularly limited. Further, the robot 2 may be other than a SCARA robot, such as a six-axis articulated robot, a dual-arm robot, or the like.

The robot 2 has a base 21 and a robot arm 22 connected to the base 21. Further, the robot arm 22 has a first arm 221 as an arm whose base end is connected to the base 21 and rotates around a first rotation axis J1 along a direction perpendicular to the base 21; It has a second arm 222 that is connected to the tip of the first arm 221 and rotates about a second rotation axis J2 that is perpendicular to the first arm 221.

Further, a working head 23 is provided at the tip of the second arm 222. The work head 23 includes a spline nut 231 and a ball screw nut 232 that are coaxially arranged at the tip of the second arm 222, and a spline shaft 233 that is inserted through the spline nut 231 and the ball screw nut 232. There is. The spline shaft 233 is rotatable with respect to the second arm 222 around a third rotation axis J3 that is a central axis of the second arm 222 and extends in the vertical direction, and is movable up and down along the third rotation axis J3.

Further, the end effector 24 is attached to the lower end of the spline shaft 233. The end effector 24 is removable and is selected as appropriate for the intended work.

The robot 2 also includes an angular velocity sensor 6 placed on the first arm 221. The angular velocity sensor 6 is arranged at a position offset from the first rotation axis J1 of the first arm 221, and detects the angular velocity ω around the first rotation axis J1 of the first arm 221. By integrating the angular velocity ω detected by the angular velocity sensor 6, the position of the first arm 221 (rotation angle around the first rotation axis J1) can be calculated.

The robot 2 also includes a first joint actuator 251 that connects the base 21 and the first arm 221 and rotates the first arm 221 with respect to the base 21 around a first rotation axis J1; and a second joint actuator 252 that connects the second arm 222 and rotates the second arm 222 with respect to the first arm 221 around a second rotation axis J2.

The robot 2 also includes a first drive mechanism 253 that rotates the spline nut 231 to rotate the spline shaft 233 around the third rotation axis J3, and a first drive mechanism 253 that rotates the ball screw nut 232 to rotate the spline shaft 233 around the third rotation axis J3. It has a second drive mechanism 254 that moves up and down in the direction along J3.

Next, the first joint actuator 251 will be explained. The first joint actuator 251 is housed within the base 21. As shown in FIG. 2, the first joint actuator 251 includes a reducer 3 that connects the base 21 and the first arm 221, a motor 4, and an encoder 5 as a position detector. .

The motor 4 is fixed to the base 21. Further, the motor 4 is, for example, an AC servo motor. However, the motor 4 is not particularly limited, and for example, a DC servo motor, a stepping motor, or the like may be used. Such a motor 4 has a shaft 41 that is an output shaft, a stator (not shown) that rotates the shaft 41, and a housing 43 that accommodates these.

The encoder 5 is arranged in line with the motor 4 along the first rotation axis J1, and is located below the motor 4. The encoder 5 includes an optical scale 51 fixed to the shaft 41 and an optical sensor 52 that detects the rotational state of the optical scale 51.

The optical scale 51 rotates together with the shaft 41 around the first rotation axis J1. Furthermore, a detection pattern (not shown) that can detect the rotation angle of the optical scale 51 is formed on the lower surface of the optical scale 51. On the other hand, the optical sensor 52 includes a light emitting element 521 that emits light toward a detection pattern on the optical scale 51, and a light receiving element 522 that receives light reflected by the detection pattern. In the encoder 5 having such a configuration, the waveform of the output signal from the light receiving element 522 changes as the optical scale 51 rotates around the first rotation axis J1. Therefore, the position (rotation angle) of the motor 4 can be detected based on this output signal.

However, the configuration of the encoder 5 is not particularly limited. For example, in this embodiment, the light-receiving element 522 is a reflective optical encoder that receives the light reflected by the detection pattern, but the light-receiving element 522 is a transmission-type optical encoder that receives the light that has passed through the detection pattern. It may also be an encoder. Alternatively, it may be an image recognition type encoder that images a detection pattern with a camera and detects the position of the motor 4 from the image taken using template patching.

The speed reducer 3 is arranged in line with the motor 4 along the first rotation axis J1, and is located above the motor 4. The speed reducer 3 reduces and outputs the rotation of the shaft 41 at a high reduction ratio, and generates high torque proportional to the reduction ratio.

The speed reducer 3 is a wave gear device. Such a reduction gear 3 includes a wave generator 31, a flex spline 33, a circular spline 36, and a cover member 39. In the speed reducer 3, the wave generator 31 serves as an input side to which the power of the motor 4 is input, and the circular spline 36 serves as an output side that decelerates and outputs the power of the motor 4.

The circular spline 36 is an annular internal gear made of a rigid body that does not substantially bend. The circular spline 36 also includes an inner main bearing 361 fixed to the base 21 and an outer main bearing 362 located outside the inner main bearing 361 and fixed to the first arm 221 via the cover member 39. ,have. Further, the inner main bearing 361 and the outer main bearing 362 are connected by a bearing 363, and the outer main bearing 362 and the inner main bearing 361 are rotatable. Furthermore, internal teeth 361b that mesh with the flexspline 33 are formed on the inner peripheral portion of the inner main bearing 361.

The flex spline 33 is arranged inside the circular spline 36. The flex spline 33 includes a flexible cylindrical part 331 that can be flexibly deformed along the outer periphery of the wave generator 31, and an annular flange part 332 connected to the upper end of the cylindrical part 331. There is. External teeth 331a that mesh with internal teeth 361b of the circular spline 36 are formed on the outer circumference of the cylindrical portion 331. The number of teeth of the external teeth 331a is set to be smaller than the number of teeth of the internal teeth 361b. The flange portion 332 is fixed to the cover member 39 together with the outer main bearing 362.

The wave generator 31 also includes a wave generation section 311 that is fixed to the shaft 41 and rotates in conjunction with the rotation of the shaft 41, and a bearing 312 that is fitted between the wave generation section 311 and the flexspline 33. are doing. The wave generation section 311 has an elliptical or oval outer circumference when viewed from above in a direction along the first rotation axis J1. That is, the wave generator 31 has a shape having a longitudinal direction and a lateral direction perpendicular to the longitudinal direction.

The wave generator 31 is in contact with the inner circumferential surface of the cylindrical portion 331 of the flex spline 33, bends the cylindrical portion 331 into an elliptical or oval shape, and connects the external teeth 331a of the cylindrical portion 331 to the internal teeth 361b of the circular spline 36. partially engage. As a result, the teeth mesh with the circular spline 36 on the long axis, and the teeth are completely separated from each other on the short axis.

When the driving force from the motor 4 is input to the wave generator 31, the engagement positions of the flex spline 33 and the circular spline 36 move sequentially in the circumferential direction, and due to the difference in the number of teeth, the flex spline 33 and the circular spline 36 move toward the first rotation axis due to the difference in the number of teeth. Rotates relatively around J1. In this embodiment, the flexspline 33 and the outer main bearing 362 are fixed to the first arm 221 via the cover member 39, and the inner main bearing 361 is fixed to the base 21, so that the first arm 221 is fixed to the base 21. It rotates around the first rotation axis J1 with respect to the first rotation axis J1.

According to such a reducer 3, the rotation input from the motor 4 to the wave generator 31 is reduced and output from the outer main bearing 362 of the circular spline 36, and it is possible to obtain a torque proportional to the reduction ratio on the output side. can.

Although the reduction gear 3 has been described above, the reduction gear 3 is not particularly limited, and may be, for example, a cyclo reduction gear (registered trademark), a planetary gear reduction gear, or the like.

The control device 9 controls the driving of the robot 2. Specifically, the control device 9 independently controls the driving of the first joint actuator 251, the second joint actuator 252, the first drive mechanism 253, and the second drive mechanism 254. Such a control device 9 is composed of, for example, a computer, and includes a processor (CPU) that processes information, a memory that is communicably connected to the processor, and an external interface that connects to an external device. ing. Various programs executable by the processor are stored in the memory, and the processor can read and execute the programs stored in the memory.

In particular, in this embodiment, a control program PP for the robot 2 is stored in the memory, and the control program PP for the robot 2, which will be described later, is realized by the processor executing this control program PP.

Next, based on FIG. 3, the conventionally used control circuit 8 for the first joint actuator 251 and its problems will be briefly described. As shown in the figure, the control circuit 8 includes a position command generation section 81, a position control section 82, a speed control section 83, and a current control section 84.

The position command generation unit 81 generates a position command for the motor 4 at every control cycle interval. The position control unit 82 generates a speed command so that the position command generated by the position command generation unit 81 and the position (rotation angle) of the motor 4 detected by the encoder 5 match. The speed control unit 83 generates a current command so that the speed determined from the position of the motor 4 detected by the encoder 5 matches the speed command. The current control unit 84 controls the current so that the current that drives the motor 4 matches the current command.

According to such feedback control, the motor 4 can be moved in accordance with the position command, and the first arm 221 is considered to be at the target position. However, since the reducer 3 is interposed between the motor 4 and the first arm 221, backlash (lost motion) of the reducer 3 and torsion ( Even if the position of the motor 4 matches the position command, the position of the first arm 221 may deviate from the target position due to the influence of factors such as hysteresis.

Therefore, the robot system 1 further controls the position of the first arm 221 to match the target position by feeding back the detection result of the angular velocity sensor 6 disposed on the first arm 221. This will be explained in detail below.

As shown in FIG. 4, the control device 9 includes a control circuit 91 that controls driving of the first joint actuator 251. The control circuit 91 also includes a position command generation section 911 that generates a position command P0 for the motor 4 at each control cycle interval, and a speed command V0 for the motor 4 based on the position command P0 generated by the position command generation section 911. a position control unit 912 that generates an acceleration command A0 to the motor 4 based on a speed command V0 from the position control unit 912; and a current control unit 914 that generates a current command E0 to 4.

Up to this point, the control circuit 91 is similar to the conventional control circuit 8, but the control circuit 91 further includes a first speed signal generation section 915 that generates the first speed signal V1 of the motor 4 based on the output of the angular velocity sensor 6; A first position signal generation section 916 that integrates the first speed signal V1 from the first speed signal generation section 915 to generate a first position signal P1 of the motor 4; a second position signal generation section 917 that generates a position signal P2; and a second speed signal generation section that differentiates the second position signal P2 from the second position signal generation section 917 to generate a second speed signal V2 of the motor 4. 918.

The first velocity signal generation unit 915 generates the first velocity signal V1 based on the output of the angular velocity sensor 6. Note that the first joint actuator 251 includes a speed reducer 3 interposed between the motor 4 and the first arm 221. Therefore, in the first speed signal generation unit 915, the speed of the first arm 221 detected from the output of the angular velocity sensor 6 is converted into the speed of the motor 4 based on the reduction ratio of the reducer 3, and the result is the first speed signal V1. Generate as. This allows the first speed signal V1 to be compared with the second speed signal V2.

The first position signal generation section 916 is an integrator, and integrates the first speed signal V1 from the first speed signal generation section 915 to generate the first position signal P1 of the motor 4. In this way, by using an integrator as the first position signal generation section 916, the first position signal P1 can be easily generated from the first velocity signal V1. However, the method of generating the first position signal P1 from the first speed signal V1 is not particularly limited, and for example, the first position signal P1 may be generated by multiplying the first speed signal V1 by a predetermined coefficient. good.

Note that the first speed signal V1 and the first position signal P1 are generated by, for example, the steps shown in FIG. First, in step S1, the control device 9 determines whether it is a request timing to acquire the angular velocity ω from the angular velocity sensor 6. If it is the request timing, the control device 9 requests the angular velocity ω from the angular velocity sensor 6 in step S2, and stores the received angular velocity ω in the storage unit in step S3. On the other hand, if it is not the request timing, the control device 9 moves to step S4. Then, in step S4, the control device 9 generates the first velocity signal V1 and the first position signal P1 by processing the angular velocity ω stored in the storage section. However, the method of generating the first speed signal V1 and the first position signal P1 is not particularly limited.

The second position signal generation section 917 generates a second position signal P2 of the motor 4 based on the output of the encoder 5. The second speed signal generation section 918 is a differentiator, and generates the second speed signal V2 of the motor 4 by differentiating the second position signal P2 from the second position signal generation section 917. In this way, by using a differentiator as the second velocity signal generation section 918, the second velocity signal V2 can be easily generated from the second position signal P2. However, the method of generating the second speed signal V2 from the second position signal P2 is not particularly limited, and for example, the second speed signal V2 may be generated by multiplying the second position signal P2 by a predetermined coefficient. good.

Then, the second position signal P2 generated by the second position signal generation unit 917 is subtracted and combined with the first position signal P1 generated by the first position signal generation unit 916, and the first position signal P1 and the second position signal P2 are combined. A differential position signal P' is generated.

Further, the second speed signal V2 generated by the second speed signal generation section 918 is subtracted and synthesized with the first speed signal V1 generated by the first speed signal generation section 915, and the first speed signal V1 and the second speed signal V2 are combined. A differential velocity signal V' is generated. Further, this differential speed signal V' is multiplied by k by a predetermined gain constant k, and then subtracted and synthesized with the second speed signal V2 generated by the second speed signal generation section 918, and the actual speed signal V of the motor 4 is ” is generated.

The position command generation unit 911 generates a position command P0 for the motor 4 at every control cycle interval.

The position control unit 912 feeds back (subtracts and synthesizes) the second position signal P2 from the encoder 5, that is, the actual position of the motor 4, to the position command P0. Then, the position control unit 912 generates a speed command based on the difference between the position command P0 and the second position signal P2, that is, so that the second position signal P2 matches the position command P0. Furthermore, the position control unit 912 generates a speed command V0 by feeding back (subtracting and combining) the differential position signal P' to this speed command and correcting it.

The speed control unit 913 feeds back (subtracts and synthesizes) the actual speed signal V'', that is, the actual speed of the motor 4, to the speed command V0.The speed control unit 913 then calculates the difference between the speed command V0 and the actual speed signal V''. In other words, the acceleration command A0 is generated so that the actual speed signal V'' matches the speed command V0.

Current control section 914 generates current command E0 based on acceleration command A0. Then, the current command E0 generated by the current control section 914 is applied to the motor 4, and the motor 4 is driven.

As described above, not only is position control performed to feed back the second position signal P2 to position command P0, but also position control is performed to feed back differential position signal P' to position command P0. That is, in the method of controlling the robot 2 of this embodiment, the first position signal P1, which is the first position of the motor 4 determined from the output of the angular velocity sensor 6 disposed on the first arm 221, and the first position signal P1, which is the first position of the motor 4, The drive of the motor 4 is controlled based on a differential position signal P' which is the difference between the second position signal P2 which is the second position of the motor 4 determined from the output of the encoder 5 which is the second position of the motor 4. Therefore, the position of the first arm 221 can be accurately aligned with the target position regardless of the presence or absence of backlash of the reducer 3, twisting between the input side and the output side of the reducer 3, etc.

Furthermore, in this embodiment, speed control is performed by feeding back the actual speed signal V" to the speed command V0. In other words, in the control method of the robot 2 of this embodiment, the angular velocity sensor 6 disposed on the first arm 221 Difference between a first speed signal V1, which is the first speed of the motor 4 determined from the output, and a second speed signal V2, which is the second speed of the motor 4, determined from the output of the encoder 5 connected to the motor 4. The drive of the motor 4 is controlled based on the actual speed signal V'' obtained from the differential speed signal V'. Therefore, the position of the first arm 221 can be more precisely aligned with the target position without being affected by backlash of the reducer 3 or twisting between the input side and the output side of the reducer 3.

The robot system 1 of this embodiment has been described above. The control method for the robot 2 applied to such a robot system 1 includes a first arm 221 as an arm and a motor 4 that rotates the first arm 221, and drives the motor 4 based on a position command P0. A method of controlling a robot 2 in which a first position signal P1, which is a first position of a motor 4 determined from an output of an angular velocity sensor 6 disposed on a first arm 221, and a position connected to the motor 4 are provided. The driving of the motor 4 is controlled based on a differential position signal P' which is the difference between the second position signal P2 which is the second position of the motor 4 determined from the output of the encoder 5 which is a detector. According to such a control method, the position of the first arm 221 can be precisely aligned with the target position.

Further, as described above, in the method for controlling the robot 2, the first position, that is, the first position signal P1, is obtained by integrating the output of the angular velocity sensor 6. Thereby, the first position signal P1 can be easily generated.

Further, as described above, in the control method for the robot 2, the first speed signal V1, which is the first speed of the motor 4 determined from the output of the angular velocity sensor 6, and the second speed of the motor 4, determined from the output of the encoder 5, are used. The driving of the motor 4 is controlled based on the differential speed signal V' that is the difference between the second speed signal V2 and the second speed signal V2. According to such a control method, the position of the first arm 221 can be precisely aligned with the target position. In this way, by performing speed control in addition to position control, the above-mentioned effects become more significant.

Furthermore, as described above, in the control method for the robot 2, the actual speed is the difference between the second speed signal V2 and the differential speed signal V', which is the difference between the first speed signal V1 and the second speed signal V2. The drive of the motor 4 is controlled based on the signal V''. According to such a control method, the position of the first arm 221 can be precisely aligned with the target position.

Furthermore, as described above, the second velocity, that is, the second velocity signal V2, is obtained by differentiating the output of the encoder 5. Thereby, the second speed signal V2 can be easily generated.

Further, as described above, the first arm 221 is connected to the motor 4 via the reducer 3. As a result, the position of the motor 4 and the position of the first arm 221 are likely to be misaligned due to backlash of the reducer 3, twisting between the input side and the output side of the reducer 3, and the like. Therefore, the method of controlling the robot 2 of this embodiment is particularly effective.

Further, as described above, the control program PP for the robot 2 applied to the robot system 1 includes the first arm 221 as an arm and the motor 4 that rotates the first arm 221, and is based on the position command P0. This is a control program for the robot that drives the motor 4, and includes the first position of the motor 4 determined from the output of the angular velocity sensor 6 disposed on the first arm 221, and the position detector connected to the motor 4. The drive of the motor 4 is controlled based on the difference between the second position of the motor 4 determined from the output of the encoder 5. According to such a control program PP, the position of the first arm 221 can be precisely aligned with the target position.

Further, as described above, the robot system 1 includes a first arm 221 that is an arm, a motor 4 that rotates the first arm 221, an angular velocity sensor 6 disposed on the first arm 221, and a motor 4. The robot 2 includes an encoder 5 that is a position detector connected to the robot 2 and detects the position of the motor 4, and a control device 9 that controls the drive of the motor 4. Further, the control device 9 controls the drive of the motor 4 based on the difference between the first position of the motor 4 determined from the output of the angular velocity sensor 6 and the second position of the motor 4 determined from the output of the encoder 5. . According to such a robot system 1, the position of the first arm 221 can be precisely aligned with the target position.

Although the robot control method, robot control program, and robot system of the present invention have been described above based on the illustrated embodiments, the present invention is not limited thereto, and the configurations of each part have similar functions. It can be replaced with any configuration having the following. Moreover, other arbitrary components may be added to the present invention.

Further, in the embodiment described above, the robot control method of the present invention is applied to the first joint actuator 251, but the present invention is not limited to this, and the robot control method of the present invention may also be applied to the second joint actuator 252. good. In this case, the angular velocity sensor 6 may be placed at a position offset from the second rotation axis J2 of the second arm 222.

Further, in the embodiment described above, the angular velocity sensor 6 is arranged on the first arm 221, but the arrangement of the angular velocity sensor 6 is not limited to this. For example, the angular velocity sensor 6 may be placed on the second arm 222. In this case, the positional deviation caused by the first joint actuator 251 and the positional deviation caused by the second joint actuator 252 can be corrected together without distinction by drive control of the first joint actuator 251. Therefore, positional deviation of the end effector 24 from the target position can be effectively suppressed.

DESCRIPTION OF SYMBOLS 1... Robot system, 2... Robot, 21... Base, 22... Robot arm, 221... First arm, 222... Second arm, 23... Work head, 231... Spline nut, 232... Ball screw nut, 233... Spline shaft, 24... End effector, 251... First joint actuator, 252... Second joint actuator, 253... First drive mechanism, 254... Second drive mechanism, 3... Reduction gear, 31... Wave generator, 311... Wave generation unit, 312 ...Bearing, 33...Flex spline, 331...Cylindrical part, 331a...External tooth, 332...Flange part, 36...Circular spline, 361...Inner main bearing, 361b...Inner tooth, 362...Outer main bearing, 363...Bearing, 39... Cover member, 4... Motor, 41... Shaft, 43... Housing, 5... Encoder, 51... Optical scale, 52... Optical sensor, 521... Light emitting element, 522... Light receiving element, 6... Angular velocity sensor, 8... Control circuit , 81... Position command generation section, 82... Position control section, 83... Speed control section, 84... Current control section, 9... Control device, 91... Control circuit, 911... Position command generation section, 912... Position control section, 913 ...Speed control section, 914...Current control section, 915...First speed signal generation section, 916...First position signal generation section, 917...Second position signal generation section, 918...Second speed signal generation section, A0...Acceleration Command, E0...Current command, J1...First rotation axis, J2...Second rotation axis, J3...Third rotation axis, P'...Difference position signal, P0...Position command, P1...First position signal, P2...second position signal, PP...control program, S1...step, S2...step, S3...step, S4...step, S5...step, V'...differential speed signal, V''...actual speed signal, V0...speed command , V1...first speed signal, V2...second speed signal, ω...angular velocity

Claims (8)

A method for controlling a robot, comprising an arm and a motor for rotating the arm, and driving the motor based on a position command, the method comprising:
Based on the difference between a first position of the motor determined from the output of an angular velocity sensor disposed on the arm and a second position of the motor determined from the output of a position detector connected to the motor. A method for controlling a robot, comprising controlling the drive of the motor. 2. The robot control method according to claim 1, wherein the first position is determined by integrating the output of the angular velocity sensor. 2. The driving of the motor is controlled based on a difference between a first speed of the motor determined from the output of the angular velocity sensor and a second speed of the motor determined from the output of the position detector. robot control method. 4. The robot control method according to claim 3, wherein driving of the motor is controlled based on a difference between the second speed and a difference between the first speed and the second speed. 4. The robot control method according to claim 3, wherein the second speed is obtained by differentiating the output of the position detector. 2. The robot control method according to claim 1, wherein the arm is connected to a motor via a speed reducer. A control program for a robot comprising an arm and a motor for rotating the arm, and driving the motor based on a position command, the program comprising:
Based on the difference between a first position of the motor determined from the output of an angular velocity sensor disposed on the arm and a second position of the motor determined from the output of a position detector connected to the motor. A robot control program, characterized in that the program controls driving of the motor. A robot comprising an arm, a motor for rotating the arm, an angular velocity sensor disposed on the arm, and a position detector connected to the motor and detecting the position of the motor;
a control device that controls driving of the motor;
The control device controls driving of the motor based on a difference between a first position of the motor determined from the output of the angular velocity sensor and a second position of the motor determined from the output of the position detector. A robot system characterized by:

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