US 11,613,013 B2Granted

Robot control device

AssigneePanasonic Intellectual Property Management Co., Ltd.

InventorsHiroyuki Nakata, Hiroyoshi Ueda, Atsumi Hashimoto, Ryosuke Yamamoto, Yasuyoshi Honuchi

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Abstract

A robot control device includes the following: a main control unit; a servo control unit, which receives a position command θc from the main control unit; and a bending correction block (24), which corrects the bending of the reduction gear connected to the servo motor. The bending correction block (24) includes the following: a first position-correction-value calculation means (63), which finds a first position-command correction value θsgc based on the position command θc; and a second position-command-correction-value calculation means (64), which finds a second position-command correction value θskc based on the interference torque τa. The servo control unit drives the servo motor based on a new position command obtained by adding the first position-command correction value θsgc and the second position-command correction value θskc to the position command θc.

Claims6

Dependent claims

A robot control device for controlling movement of a robot arm having a first joint shaft having a first position response frequency and a second joint shaft having a second position response frequency different from the first position response frequency, the first joint shaft driven through a reduction gear connected to a servo motor, the robot control device comprising:

a hardware processor configured to execute at least one program and cause the robot control device to:
transmit a first position command to the first joint shaft;
and
perform bending correction to correct a position error of the robot arm, the position error being due to bending of the reduction gear, the hardware processor further configured:
to calculate separately a gravitational torque and an interference torque, the interference torque is applied from the second joint shaft, as part of an external torque causing the bending of the reduction gear,
wherein, in the calculation for separating the gravitational torque and the interference torque, the hardware processor is configured:
to calculate, based on the first position command, the external torque causing the bending of the reduction gear by a dynamic calculation,
to calculate, based on the first position command, the gravitational torque as part of the external torque causing the bending of the reduction gear by a gravity calculation, the gravity calculation being performed through the dynamic calculation with a speed and an acceleration component of the first position command set to zero, and
to calculate, by subtracting the gravitational torque calculated by the gravity calculation from the external torque calculated by the dynamic calculation, the interference torque, the interference torque being due to interference to which the first joint shaft is subjected, and
whereby the gravitational torque and the interference torque are calculated separately;
to determine a first position-command correction value based on the separated gravitational torque;
to determine a second position-command correction value by multiplying the separated interference torque by coefficients for amplitude compensation and phase compensation;
and
to perform servo control to drive the servo motor based on a second position command obtained by adding the first position-command correction value determined from the separated gravitational torque and the second position-command correction value determined from the separated interference torque to the first position command.

11 more elements

a hardware processor configured to execute at least one program and cause the robot control device to:
transmit a first position command to the first joint shaft;
and
perform bending correction to correct a position error of the robot arm, the position error being due to bending of the reduction gear, the hardware processor further configured:
to calculate separately a gravitational torque and an interference torque, the interference torque is applied from the second joint shaft, as part of an external torque causing the bending of the reduction gear,
wherein, in the calculation for separating the gravitational torque and the interference torque, the hardware processor is configured:
to calculate, based on the first position command, the external torque causing the bending of the reduction gear by a dynamic calculation,
to calculate, based on the first position command, the gravitational torque as part of the external torque causing bending of the robot arm by a gravity calculation, the gravity calculation being performed through the dynamic calculation with a speed and an acceleration component of the first position command set to zero, and
to calculate, by subtracting the gravitational torque calculated by the gravity calculation from the external torque calculated by the dynamic calculation, the interference torque, the interference torque being due to interference to which the first joint shaft is subjected, and
whereby the gravitational torque and the interference torque are calculated separately;
to determine a first position-command correction value based on the separated gravitational torque;
and
to determine a current compensation value by multiplying the separated interference torque by coefficients for amplitude compensation and phase compensation;
and
to perform servo control to drive the servo motor based on following commands:
a second position command obtained by adding the first position-command correction value determined from the separated gravitational torque to the first position command, and
a new motor current command obtained by adding the current compensation value determined separated from the interference torque to a motor current command generated based on the second position command.

14 more elements

Dependencies are inferred from the claim text.

Facts

Application: 16/726,302Filed 24 Dec 2019 · continuation
Priority: JP JP2017-13562011 Jul 2017
Published: US 2020/0130181 A130 Apr 2020
Granted: 28 Mar 2023
Term ends: Not estimatedThe source records don’t support an estimate.

Classification11 codes

B25J 9/1635
Characterised by the control loop: flexible-arm control
B25J 9/1638
Characterised by the control loop: compensation for arm bending/inertia, pay load weight/inertia
B25J 9/1633
Characterised by the control loop: compliant, force, torque control, e.g. combined with position control
B25J 9/1694
Program controls: characterised by use of sensors other than normal servo-feedback from position, speed or acceleration sensors, perception…