Motor Control Apparatus Torque Limiting Feedforward Stability
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Solution Overview
Problem
Existing motor control systems face instability due to the lack of external interference torque consideration in feedforward control, leading to uncontrolled torque instruction values that exceed motor limits, resulting in reduced model tracking performance and unstable behavior of controlled objects.
Innovation Solution
A motor control apparatus with both feedback and feedforward control systems, where the feedforward control includes a first torque limiting part to limit model torque instruction values within a defined range, and optionally a compensation part to adjust torque limits based on driving states and characteristics, ensuring stable torque instruction values are generated.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the feedforward control system generates model torque signal without considering external interference torque, then the control system is simple, but the torque instruction value greatly exceeds allowable range and model tracking performance is reduced
Solution Approach 1:
The patent applies preliminary action by introducing a torque limiting part in the feedforward control system that proactively limits the model torque instruction value before it is output to the feedback control system. This prevents the torque instruction value from exceeding the allowable range in the first place, rather than correcting it after the fact. The torque limiting part compares the generated model torque instruction value with a predetermined limit value and outputs only the limited value, ensuring reliability is maintained while keeping the system structure relatively simple.
2Stability of the object's composition
If torque limiting processing is performed only in feedback control system, then the feedback control is stable, but the model torque value greatly deviates from limit range and model tracking performance is reduced
Solution Approach 1:
The patent implements preliminary action by placing the torque limiting function in the feedforward control path before the feedback control system. The torque limiting part预先 limits the model torque instruction value generated by the feedforward control, ensuring it stays within the allowable range before being processed by the feedback control system. This preliminary limitation prevents large deviations and maintains model tracking performance while allowing the feedback control system to operate stably with smaller correction tasks.
Solution Approach 2:
The torque limiting part acts as an intermediary between the feedforward control system and the feedback control system. It receives the model torque instruction value from the feedforward control, applies limitation processing, and outputs the limited value to the feedback control system. This intermediary component ensures that the feedback control system receives torque values within the allowable range, improving model tracking performance while maintaining feedback control stability.
3Speed
If no torque limiting is applied to model torque instruction value, then the control system responds quickly, but the torque instruction value exceeds motor limits and controlled object behavior becomes unstable
Solution Approach 1:
The patent applies preliminary action by implementing torque limiting in the feedforward control path, which proactively constrains the model torque instruction value before it reaches the motor control system. The torque limiting part compares the generated torque value with a predetermined limit and outputs only the limited value, preventing excessive torque that would cause instability. This approach maintains quick response by not adding complex feedback correction loops, while ensuring stability through the preliminary torque constraint.
Data Source
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AI summary
The present invention implements a model-tracking motor control apparatus for stabilizing behavior of a controlled object. The control apparatus (1) includes: a feedback control part (20), generating a driving torque instruction value used to enable the servo motor (2) to perform driving based on a detection value of an encoder (4) that performs detection on a rotational state of a servo motor (2); and a feedforward control part (10), generating a model torque instruction value, and outputting the model torque instruction value to the feedback control part (20), where the feedforward control part (10) has a model torque limiter (104) that limits the model torque instruction value within a first limit range.