Servo Speed Command Damping for Low-Frequency End Oscillation
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Solution Overview
Problem
In motor control systems with semi-closed configurations, especially in the FA field, it is challenging to realize damping control within the servomotor control device responsible for the speed control system due to equipment replacement and maintainability issues, as the position controller cannot perform damping control, leading to oscillations at low frequencies.
Innovation Solution
A motor control device that includes a position command estimator and a speed command generator to calculate and output an actual speed command, which is used by a speed controller to prevent oscillations at the mechanical end, without relying on position command processing by the upper layer system control device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If damping control is implemented by processing position command in upper layer system control device, then oscillation of end section can be suppressed, but device complexity increases and maintainability deteriorates
Solution Approach 1:
The damping control function is extracted from the upper layer system control device and relocated to the servomotor control device. This extraction eliminates the need for complex filter switching mechanisms and command direction detecting means in the upper layer device, thereby reducing device complexity while maintaining the ability to suppress end section oscillation through speed command processing alone.
Solution Approach 2:
The servomotor control device performs damping control independently using its own speed command processing capability, without requiring external intervention from the upper layer system control device. The position command estimator and speed command generator work autonomously within the servomotor control device to estimate position commands and generate damped speed commands,实现ing self-service damping control.
2Object-affected harmful factors
If position controller processes position command for damping control, then damping effect is achieved, but ease of operation deteriorates due to inability to realize damping control in speed control system
Solution Approach 1:
Instead of processing the position command to achieve damping control, the invention inverts the approach by processing the speed command. The position command estimator estimates the position command from speed command and position response, then the speed command generator uses this estimate to generate a damped speed command. This inversion allows damping control to be realized within the speed control system, improving ease of operation.
3Object-affected harmful factors
If damping filter is applied to position command, then oscillation is suppressed, but response time increases due to low-pass filtering
Solution Approach 1:
The invention changes the parameter being filtered from position command to speed command. By applying the damping filter to the speed command rather than the position command, the system avoids the severe phase lag and response delay introduced by low-pass filtering of position commands. The position command estimator provides the necessary filtering effect on position information without directly filtering the position command, thereby maintaining faster response time while still suppressing oscillation.
Data Source
AI summary
This motor control device receives a speed command from an upper layer system control device having a position controller, the motor control device having: a position command estimator that calculates an estimate of a position command on the basis of the speed command and a motor axis position response; and a speed command generator that generates an actual speed command on the basis of the estimate so that an end section of a machine connected to the motor does not oscillate, wherein the actual speed command is output from the speed command generator to a speed controller.