Motor Control System for Dynamic Inertia Adaptation
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Solution Overview
Problem
Conventional motor control systems fail to quickly adapt to changes in load inertia, leading to increased time required for achieving fixed-position stop control, which is essential for improving processing efficiency in working machines.
Innovation Solution
A method that uses a position controller, speed controller, and torque controller to compute the deviation between rotational speed and acceleration, determining the gain of the position controller based on the maximum value of absolute acceleration, allowing for high-speed detection of load inertia changes and stable fixed-position stop control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If control parameters are adjusted based on large load inertia to prevent overshoot, then stability is improved, but the time required for fixed-position stop control increases
Solution Approach 1:
The position control gain is made dynamically adjustable based on detected load inertia. The system detects inertia by analyzing the relationship between torque command and acceleration feedback, then automatically adjusts the position control gain accordingly. This allows the system to optimize stopping performance for each specific load without manual parameter adjustment, resolving the contradiction between stability and response time.
Solution Approach 2:
The system changes the position control gain parameter based on detected load characteristics. By detecting load inertia through torque-acceleration analysis and adjusting the gain parameter accordingly, the system adapts to different tool weights and inertia values, achieving both stability and fast response without compromising either aspect.
2Measurement precision
If multiple acceleration and deceleration steps are used for inertia estimation, then measurement precision is improved, but the time required for estimation increases
Solution Approach 1:
The system performs inertia detection during normal operation phases (acceleration and deceleration) without requiring separate dedicated detection phases. By utilizing existing operational data (torque commands and acceleration feedback) that are already available during tool exchange operations, the system achieves inertia estimation without adding extra time-consuming steps, thus maintaining both accuracy and efficiency.
3Adaptability or versatility
If conventional inertia estimation methods are used, then adaptability to load changes is improved, but processing speed decreases
Solution Approach 1:
The system replaces complex multi-step mechanical testing methods with a simplified computational approach. By using torque command and acceleration feedback data already available in the control system, and applying iterative least squares calculation, the system achieves fast inertia detection without requiring separate mechanical testing procedures, thus maintaining adaptability while significantly improving processing speed.
Data Source
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AI summary
Provided herein is a motor control system capable of detecting a change in the load inertia of a motor at high speed and achieving fixed-position stop control at high speed even when the load inertia of the motor is changed. After the rotational speed of a rotor of a motor M is reduced to orientation speed, a control section 17 gives a deviation between a speed designated by a position loop speed command vc and a 2 squared speed v2 to a speed controller 14. Before start of orientation control, an automatic tuning section 18 computes the acceleration of the rotor and determines a gain C of a position controller 15 based on the maximum value of the absolute value of the acceleration.