Motion Control Method Reducing Motor Overshoot
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Solution Overview
Problem
The Proportional Integral Derivative (PID) control method in motor servo systems often results in overshoot and instability due to changes in system parameters and external disturbances.
Innovation Solution
A motion control method that calculates current acceleration based on the difference between the current and target positions, and current velocity, using the formula a(t)=K2(s0−s(t))−2Kv(t), to iteratively control the motor, ensuring smooth acceleration and deceleration, thereby stabilizing the system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If PID control method is used to control motor servo system, then the control of duty cycle of voltage output PWM signal can be realized, but the system produces greater overshoot or even becomes unstable due to change of system parameters and external disturbances
Solution Approach 1:
The patent changes the control parameters from traditional PID (position error-based) to model-based parameters (velocity and acceleration). By using a motion model that directly calculates velocity v(t) and acceleration a(t) based on position s(t), the system adapts to parameter changes and external disturbances more effectively, reducing overshoot and improving stability.
Solution Approach 2:
The patent implements feedback by continuously measuring current position s(t) and using it to update velocity and acceleration calculations in real-time. The iterative process repeatedly measures position, calculates new velocity and acceleration, and adjusts motor output, creating a closed-loop feedback system that maintains stability despite disturbances.
2Ease of operation
If PID control method is used, then the duty cycle of voltage output PWM signal can be controlled, but the system becomes unstable under external disturbances
Solution Approach 1:
The patent replaces the traditional PID control mechanism with a model-based control approach. Instead of using complex PID algorithms that require tuning and are sensitive to disturbances, the system uses direct mathematical relationships from motion models (v(t) = ∫a(t)dt, s(t) = ∫v(t)dt) to control motor output, simplifying the control implementation while improving reliability.
3Manufacturing precision
If traditional position control is used, then the target position can be reached, but vibration and overshoot occur during motion
Solution Approach 1:
The patent transitions from static position control to dynamic control by incorporating velocity and acceleration into the control loop. By calculating and controlling v(t) and a(t) based on current position s(t), the system dynamically adjusts motion parameters to achieve smooth acceleration and deceleration, eliminating vibration and overshoot while maintaining position accuracy.
Data Source
AI summary
A motion control method includes: (a) obtaining a current position and a current velocity of a control object at a current time; (b) obtaining a current acceleration based on the current position and the current velocity, wherein the current acceleration has a positive correlation with a difference between the current position and a target position as well as a negative correlation with the current velocity; (c) controlling a motor for driving the control object utilizing the current acceleration; and (d) iteratively performing the steps (a)-(c) until the control object reaches the target position. A motion trajectory planning method and a motion control device are further provided. Through the above-mentioned way, the present disclosure could realize the smooth acceleration and smooth deceleration of the motor. As a result, smooth motion trajectory, less vibration, and stable motor with less overshoot could be achieved.