Servo Gain Switching for Stable Oscillation Machining
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Solution Overview
Problem
Existing oscillation machining technologies face instability during machining operations, leading to inefficiencies and idle operations where chips are not effectively shredded.
Innovation Solution
A servo controller system that includes an oscillation command generating unit, position control unit, speed control unit, current control unit, and a gain changing unit, which adjusts control gains during oscillation operations to stabilize machining by modifying the oscillation frequency and amplitude, ensuring efficient chip shredding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If oscillation machining is performed with fixed control gain, then the control system maintains consistent response characteristics, but machining stability deteriorates due to oscillation-induced vibrations and trackability issues
Solution Approach 1:
The control gain is dynamically adjusted based on the machining state. When oscillation machining is detected, the control gain is reduced to a predetermined value to suppress vibrations and improve stability. When oscillation machining is not performed, the control gain is restored to its original value to maintain high trackability. This dynamic adjustment resolves the contradiction between stability during oscillation and trackability during normal operation.
Solution Approach 2:
The control gain parameter is changed based on the machining mode. By detecting whether oscillation machining is being performed and adjusting the control gain accordingly, the system optimizes performance for each machining state. This parameter change approach allows the system to achieve both high stability during oscillation and high trackability during conventional machining.
2Measurement precision
If high control gain is used to improve trackability, then position accuracy improves, but oscillation-related instabilities increase leading to machining disruptions
Solution Approach 1:
The control gain is dynamically switched between high and low values based on the machining mode. During oscillation machining, the gain is reduced to prevent instabilities. During conventional machining, the gain is maintained at high levels for superior position accuracy and trackability. This dynamic switching resolves the contradiction between position accuracy and oscillation stability.
3Reliability
If control gain is reduced to suppress oscillation vibrations, then machining stability improves, but position accuracy and trackability deteriorate
Solution Approach 1:
The control gain is dynamically adjusted based on the machining state. During oscillation machining, the gain is reduced to suppress vibrations and maintain stability. During conventional machining, the gain is restored to high values to ensure high position accuracy and trackability. This conditional dynamic adjustment resolves the contradiction between stability during oscillation and precision during normal operation.
Data Source
AI summary
A servo controller 20 includes: an oscillation command generating unit 23 that generates an oscillation command for causing the workpiece W and the tool 14 to relatively oscillate; at least one of a position control unit 22 that generates a position command for causing the workpiece W and the tool 14 to relatively move, a speed control unit 24 that generates a speed command for causing the workpiece W and the tool 14 to relatively move, and a current control unit 25 that generates a torque command for driving the plurality of axes; and a gain changing unit 21 that changes a control gain, in which the oscillation command generating unit 23 transmits a signal outputted when oscillating operation is started to the gain changing unit 21, and the gain changing unit 21 changes the control gain.