Actuator Control Using Time Optimal Feedback for Stability
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Solution Overview
Problem
Conventional actuator control methods, such as PID control and time optimal control, face instability and difficulty in converging control outputs due to lack of feedback elements, especially when external forces change, leading to issues with control speed and stability.
Innovation Solution
An actuator control method that incorporates feedback elements by calculating and updating switching times and end times using maximum acceleration and deceleration values, incorporating residual energy reduction to converge control outputs to zero, thereby balancing control speed and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If PID control is used to ensure stability, then control stability is improved, but control speed deteriorates due to delay
Solution Approach 1:
The patent pre-calculates the optimal control trajectory and switching times before control execution. By determining the entire control sequence in advance based on system parameters and target state, the control actions are prepared beforehand, eliminating real-time calculation delays and achieving both fast response and stability.
Solution Approach 2:
The patent incorporates feedback by measuring the actual controlled variable and comparing it with the target value. Based on the deviation, the system adjusts the control trajectory and switching times in real-time, ensuring the controlled object reaches the target accurately while maintaining fast response through continuous correction.
2Speed
If control gains are increased to improve control speed, then control speed is improved, but control stability deteriorates
Solution Approach 1:
The patent determines the complete control trajectory and switching times in advance based on system parameters, eliminating the need for high control gains. The pre-calculated optimal path ensures fast response without requiring aggressive gain adjustments that would compromise stability.
Solution Approach 2:
The patent dynamically adjusts control parameters by recalculating the trajectory and switching times based on actual system state and deviations. This dynamic adaptation allows the system to maintain optimal performance across varying conditions without relying on fixed high gains that could cause instability.
3Measurement precision
If sliding mode control is used to eliminate load fluctuation influence, then control accuracy is improved, but control complexity increases due to infinite speed requirement
Solution Approach 1:
The patent pre-calculates the optimal control trajectory and switching times before execution, eliminating the need for infinite-speed switching required by sliding mode control. By determining the complete control sequence in advance, the system achieves accurate load fluctuation compensation without requiring impractically fast switching mechanisms.
Solution Approach 2:
The patent uses feedback to measure actual position and velocity, then recalculates the trajectory and switching times based on deviations from the target. This feedback mechanism provides accurate load fluctuation compensation through practical, finite-speed adjustments rather than theoretical infinite-speed switching.
4Speed
If time optimal control without feedback is used, then control speed is improved, but control accuracy deteriorates due to inability to handle target deviations
Solution Approach 1:
The patent pre-calculates the optimal control trajectory and switching times based on system parameters and target state, enabling fast response. The feedforward component provides the speed advantage of time optimal control while the subsequent feedback ensures accuracy by correcting any deviations from the target.
Solution Approach 2:
The patent incorporates feedback by measuring the actual controlled variable and comparing it with the target value. Based on the deviation, the system adjusts the control trajectory and switching times in real-time, ensuring the controlled object reaches the target accurately while maintaining the fast response characteristics of time optimal control.
Data Source
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AI summary
In an actuator control method and an actuator control device, time optimal control is used, and a switching time (t1) at which an acceleration output is switched to a deceleration output, and an end time (t2) of the deceleration output are calculated using a maximum acceleration (αp) and a maximum deceleration (αm) at the time of a maximum output of a control force, the control force of an actuator is set as a maximum acceleration output from the calculation time (t0) to the switching time (t1), the control force of the actuator is set as a maximum deceleration output from the switching time (t1) to the end time (t2), output of the control force is ended at the end time (t2), and the switching time (t1) and the end time (t2) are repeatedly calculated, and updated for each preset time, further, the control output is reduced along with decrease of residual energy, which is a sum of remaining work and kinetic energy of a control system. From this, an element of feedback control is incorporated in the time optimal control, and the control output is converged after the end of the control.