Motor controller and method for controlling motor
A motor controller includes memory, and processing circuitry that controls a motor based on a position command and based on a position detection value corresponding to a detected position of the motor, calculates a tolerance position error in a successive manner based on the position command and based on a control parameter used to control the motor, calculates a position error maximum threshold that depends on the tolerance position error, detects an abnormality based on the position error maximum threshold, and triggers an indication when the abnormality is detected.
1. A motor controller, comprising:
memory; and
processing circuitry configured to
control a motor based on a position command and based on a position detection value corresponding to a detected position of the motor,
calculate a tolerance position error in a successive manner based on the position command and based on a control parameter used to control the motor,
calculate a position error maximum threshold that depends on the tolerance position error,
detect an abnormality based on the position error maximum threshold, and
trigger an indication when the abnormality is detected, wherein
the processing circuitry is further configured to fix the position error maximum threshold at a predetermined timing, and stop fixing the position error maximum threshold at a point of time when a position command velocity that is rate of change in time of the position command restarts increasing.
2. The motor controller according to claim 1 , wherein the processing circuitry is further configured to calculate the position error maximum threshold by adding a predetermined quantity to the tolerance position error in a direction of the position command velocity.
3. The motor controller according to claim 1 , wherein the predetermined timing comprises a timing at which the position command velocity starts decreasing.
4. The motor controller according to claim 1 , wherein the processing circuitry is further configured to fix the position error maximum threshold at a present value of the position error maximum threshold.
5. The motor controller according to claim 1 , wherein the control parameter comprises at least one gain from among a position loop gain and a feedforward gain that are used in the control of the motor.
6. The motor controller according to claim 1 , wherein the processing circuitry is further configured to detect the abnormality by comparing the position error maximum threshold with a position error that is a difference between the position command and the position detection value.
7. A method for controlling a motor, comprising:
controlling the motor based on a position command and based on a position detection value corresponding to a detected position of the motor;
calculating a tolerance position error in a successive manner based on the position command and based on a control parameter used in the controlling the motor;
calculating a position error maximum threshold that depends on the tolerance position error;
fixing the position error maximum threshold at a predetermined timing, and stopping fixing the position error maximum threshold at a point of time when a position command velocity that is a rate of change in time of the position command restarts increasing;
detecting an abnormality based on the position error maximum threshold; and
triggering an indication when the abnormality is detected.
8. The motor controller according to claim 3 , wherein the processing circuitry is further configured to fix the position error maximum threshold at a present value of the position error maximum threshold.
9. The motor controller according to claim 2 , wherein the control parameter comprises at least one gain from among a position loop gain and a feedforward gain that are used in the control of the motor.
10. The motor controller according to claim 4 , wherein the control parameter comprises at least one gain from among a position loop gain and a feedforward gain that are used in the control of the motor.
11. The motor controller according to claim 3 , wherein the control parameter comprises at least one gain from among a position loop gain and a feedforward gain that are used in the control of the motor.
12. The method according to claim 7 , wherein the calculating calculates the position error maximum threshold by adding a predetermined quantity to the tolerance position error in a direction of the position command velocity.
13. The method according to claim 7 , wherein the fixing fixes the position error maximum threshold at a present value of the position error maximum threshold.
14. The method according to claim 7 , wherein the detecting detects the abnormality by comparing the position error maximum threshold with a position error that is a difference between the position command and the position detection value.