Motor Control Device Vibration Suppression via Predistorter Adjustment
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Solution Overview
Problem
Conventional motor control devices are influenced by vibrations attributed to roughness in detecting resolution and mechanical resonance, leading to reduced following performance and inability to suppress these vibrations effectively.
Innovation Solution
The motor control device includes a state quantity detector, feedforward controller, variable predistorter, feedback controller, vibration suppression controller, manipulation quantity controller, and adjustment calculator, which adjusts the predistorter's transfer characteristic to match the manipulation-quantity command value, using IIR or FIR filters and adaptive algorithms to minimize deviations and control gain reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If predistorter adjustment is performed using conventional methods, then transfer characteristic matching is improved, but vibrations occur due to roughness in detecting resolution and mechanical resonance
Solution Approach 1:
The vibration suppression controller performs preliminary action by suppressing vibrations before they affect the predistorter adjustment process. The controller predicts manipulation quantities that would cause vibrations and subtracts these from the command values, preventing vibration generation during the adjustment process rather than correcting it afterward.
Solution Approach 2:
The vibration suppression controller acts as an intermediary between the feedforward controller and the manipulation quantity controller. It receives manipulation quantity command values, suppresses vibration components, and outputs corrected command values to the manipulation quantity controller, thereby mediating the conflict between accurate predistorter adjustment and vibration suppression.
2Object-generated harmful factors
If feedback controller gain is reduced during predistorter adjustment, then vibrations are suppressed, but following performance deteriorates
Solution Approach 1:
The vibration suppression controller performs preliminary vibration suppression by predicting and subtracting vibration-causing manipulation quantities from the command values before they reach the manipulation quantity controller. This allows the feedback controller to maintain its original gain without causing vibrations, as the vibration suppression is already performed in advance by the vibration suppression controller.
Solution Approach 2:
The vibration suppression controller creates a copy of the manipulation quantity command value and processes it separately to extract vibration components. By working with a copy rather than the original command value, it can suppress vibrations without affecting the overall control loop's following performance.
3Measurement precision
If state quantity detector resolution is improved, then measurement precision is enhanced, but device complexity increases
Solution Approach 1:
The vibration suppression controller replaces the need for high-resolution mechanical detectors by using computational methods to predict and suppress vibrations. Instead of relying on hardware with higher resolution, the system uses software-based vibration prediction and suppression algorithms to achieve smooth operation without requiring more complex detection hardware.
Data Source
AI summary
A motor control device of the present invention includes a position detector (107), a feedforward controller, a predistorter, a feedback controller, a vibration suppression controller, a torque controller, a torque estimator, and an adjustment calculator. The vibration suppression controller receives a manipulation-quantity command value derived by addition of a feedforward manipulation quantity and a feedback manipulation quantity, and outputs an actual manipulation-quantity command value corresponding to the received manipulation-quantity command value. The torque controller controls a manipulation quantity generated by the motor so that the manipulation quantity matches the actual manipulation-quantity command value. The adjustment calculator adjusts a transfer characteristic of the predistorter such that the transfer characteristic becomes equal to a transfer characteristic from the manipulation-quantity command value to the manipulation quantity.