# US 10,919,150 B2 · Motor control system, control method for motor control system, and robot system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,919,150 B2 - Document ID: US10919150B2 - Status: Granted - Kind: B2 - Application number: 16/614,410 - Filed: 2018-05-17 - Published: 2020-06-11 - Granted: 2021-02-16 - Earliest claimed: 2017-05-18 - Assignees: Kawasaki Jukogyo Kabushiki Kaisha - Applicants: Kawasaki Jukogyo Kabushiki Kaisha - Inventors: Nobutaka Tsuboi - Web page: https://patentgrep.com/patent/US10919150B2 ## CPC - B25J 9/1628: {characterised by the control loop} - H02P 6/10: Arrangements for controlling torque ripple, e.g. providing reduced torque ripple - B25J 9/126: {Rotary actuators} - B25J 13/00: Controls for manipulators (program controls B25J9/16) - G05B 19/19: characterised by positioning or contouring control systems, e.g. to control position from one programmed point to another or to control movement along a programmed continuous path - G05B 19/416: characterised by control of velocity, acceleration or deceleration (G05B19/19 takes precedence) - G05D 3/12: using feedback - H02P 29/40: Regulating or controlling the amount of current drawn or delivered by the motor for controlling the mechanical load - B25J 9/1641: {compensation for backlash, friction, compliance, elasticity in the joints} - G05B 2219/41059: Play in gear, screw backlash, lost motion - G05B 2219/50391: Robot - B25J: MANIPULATORS; CHAMBERS PROVIDED WITH MANIPULATION DEVICES ({manipulators specially adapted for use in surgery A61B34/70; manipulators used in cleaning hollow articles B08B9/04}; manipulators associated with rolling mills B21B39/20; manipulators associated with forging machines B21J13/10; {manipulators associated with picking-up and placing mechanisms B23P19/007}; means for holding wheels or parts thereof B60B30/00; {vehicles with ground-engaging propulsion means, e.g. walking members B62D57/02, B62D57/032; devices for picking-up and depositing articles or materials between conveyors B65G47/90, B65G47/91; manipulators with gripping or holding means for transferring packages B65H67/065}; cranes B66C; {manipulators used in the protection or supervision of pipe-line installations F17D5/00; walking equipment adapted for nuclear steam-generators F22B37/006}; manipulators specially adapted for, or associated with, nuclear reactors G21C; {apparatus used for handling wafers during manufacture or treatment of semiconductor H10P72/50}) - H02P: CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS - G05B: CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS (systems for controlling or regulating non-electric variables G05D; systems for regulating electric or magnetic variables G05F; control devices or systems insofar as characterised by mechanical features only G05G) - G05D: SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES ## Abstract A motor control system including an input shaft connected to an output shaft of the motor and an output shaft connected to a load, the system including: a detection unit for detecting a rotation speed of the output shaft; a speed deviation generation unit generating a speed command position and calculates a speed deviation between the speed command and rotation speed of the output shaft; an angular transmission error compensation unit estimated between a rotation angle of the output shaft and of the speed reducer, and corrects the speed command, speed deviation, or rotation speed of the output shaft detected based on the event detected by the detection unit, based on the estimated angular transmission error; a current command generation unit generates a current command based on the speed deviation; and a current control unit controls a current supplied to the motor based on the current command. ## Claims ### Claim 1 A motor control system that controls a motor by controlling a current supplied to the motor based on a position command input from a host device and controls an operation of a speed reducer including an input shaft connected to an output shaft of the motor and an output shaft connected to a load, the motor control system comprising: a detection unit that detects an event for detecting a rotation speed of the output shaft of the motor; a speed deviation generation unit that generates a speed command based on the position command and calculates a speed deviation which is a deviation between the speed command and the rotation speed of the output shaft of the motor detected based on the event detected by the detection unit; an angular transmission error compensation unit that estimates an angular transmission error between a rotation angle of the output shaft of the motor and a rotation angle of the output shaft of the speed reducer, and corrects the speed command, the speed deviation, or the rotation speed of the output shaft of the motor detected based on the event detected by the detection unit, based on the estimated angular transmission error; a current command generation unit that generates a current command based on the speed deviation; and a current control unit that controls a current supplied to the motor based on the current command. ### Claim 2 (depends on 1) The motor control system according to claim 1, wherein the speed command is a speed feedforward command obtained by time-differentiating the position command. ### Claim 3 (depends on 2) The motor control system according to claim 2, wherein the angular transmission error compensation unit corrects the speed command by correcting the speed feedforward command based on the estimated angular transmission error. ### Claim 4 (depends on 1) The motor control system according to claim 1, wherein the detection unit detects an event for detecting a rotation angle and a rotation speed of the output shaft of the motor, and wherein the speed command is a value obtained by adding a speed feedforward command obtained by time-differentiating the position command, and a gain speed command obtained by multiplying a deviation between the position command and the rotation angle of the output shaft of the motor detected based on the event detected by the detection unit by a position proportional gain. ### Claim 5 (depends on 4) The motor control system according to claim 4, wherein the angular transmission error compensation unit corrects the speed command by correcting the speed feedforward command based on the estimated angular transmission error. ### Claim 6 (depends on 5) The motor control system according to claim 5, wherein the angular transmission error compensation unit further corrects the position command based on the estimated angular transmission error, and wherein the speed command is a value obtained by adding a speed feedforward command obtained by time-differentiating the position command input from the host device and a gain speed command obtained by multiplying a deviation between the corrected position command and the rotation angle of the output shaft of the motor detected based on the event detected by the detection unit by a position proportional gain. ### Claim 7 (depends on 1) The motor control system according to claim 1, wherein the angular transmission error compensation unit estimates the angular transmission error based on a periodic function that models a periodic variation of the angular transmission error. ### Claim 8 (depends on 1) The motor control system according to claim 1, wherein the speed reducer is a strain wave gearing. ### Claim 9 A control method for a motor control system that controls a motor by controlling a current supplied to the motor based on a position command input from a host device and controls an operation of a speed reducer including an input shaft connected to an output shaft of the motor and an output shaft connected to a load, the motor control system comprising: a detection unit that detects an event for detecting a rotation speed of the output shaft of the motor; a speed deviation generation unit that generates a speed command based on the position command and calculates a speed deviation which is a deviation between the speed command and the rotation speed of the output shaft of the motor detected based on the event detected by the detection unit; an angular transmission error compensation unit that estimates an angular transmission error between a rotation angle of the output shaft of the motor and a rotation angle of the output shaft of the speed reducer, and corrects the speed command, the speed deviation, or the rotation speed of the output shaft of the motor detected based on the event detected by the detection unit, based on the estimated angular transmission error; a current command generation unit that generates a current command based on the speed deviation; and a current control unit that controls a current supplied to the motor based on the current command. ### Claim 10 A robot system comprising: a robot arm; a motor which is a drive source of a joint of the robot arm; a speed reducer including an input shaft connected to an output shaft of the motor and an output shaft connected to the joint of the robot arm; a command unit that generates a position command; and a motor control system that controls an operation of the motor by controlling a current supplied to the motor based on the position command generated by the command unit, wherein the motor control system includes: a detection unit that detects an event for detecting a rotation speed of the output shaft of the motor; a speed deviation generation unit that generates a speed command based on the position command and calculates a speed deviation which is a deviation between the speed command and the rotation speed of the output shaft of the motor detected based on the event detected by the detection unit; an angular transmission error compensation unit that estimates an angular transmission error between a rotation angle of the output shaft of the motor and a rotation angle of the output shaft of the speed reducer, and corrects the speed command, the speed deviation, or the rotation speed of the output shaft of the motor detected based on the event detected by the detection unit, based on the estimated angular transmission error; a current command generation unit that generates a current command based on the speed deviation; and a current control unit that controls a current supplied to the motor based on the current command.