Actuator Control Method Using Feedback-Updated Time Optimal Trajectory

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Solution Overview

Problem

Conventional actuator control methods, such as PID control, face instability and overshoot due to load fluctuations, and time optimal control lacks feedback mechanisms, making it difficult to accurately reach target positions without modifying the output pattern.

Innovation Solution

An actuator control method that incorporates feedback by calculating and updating the switching time and end time of acceleration and deceleration outputs using measured maximum acceleration and deceleration values, allowing for recalculation at preset intervals to adjust the control trajectory based on deviation and velocity, ensuring stable control.

Engineering Contradictions & Design Principles

VSEngineering 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 and overshoot occurs due to load fluctuation

Engineering Contradiction:
Improvecontrol stabilityVSAvoidcontrol speed
Core Design Contradiction:
Stability of the object's compositionVSSpeed

Solution Approach 1:

The patent incorporates feedback elements into time optimal control by continuously calculating the deviation between target position and actual position, and updating control parameters (switching time t1 and end time t2) based on this feedback. This allows the system to maintain stability while achieving fast response, resolving the contradiction between stability and speed.

Inventive Principle:
Principle #23Feedback

2Speed

If time optimal control is used to achieve fastest response, then control speed is improved, but control accuracy deteriorates due to lack of feedback mechanism

Engineering Contradiction:
Improvecontrol speedVSAvoidcontrol accuracy
Core Design Contradiction:
SpeedVSManufacturing precision

Solution Approach 1:

The patent adds feedback calculation to time optimal control by computing deviation X between target and actual position at each control period, and using this feedback to recalculate switching time t1 and end time t2. This modification enables the system to maintain both fast response and high accuracy by adapting the control trajectory based on actual system state.

Inventive Principle:
Principle #23Feedback

3Stability of the object's composition

If sliding mode control is used to eliminate load fluctuation influence, then control stability is improved, but control complexity increases due to infinite switching speed requirement

Engineering Contradiction:
Improvecontrol stabilityVSAvoidcontrol complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The patent changes the control parameters (switching time t1 and end time t2) dynamically based on system state feedback, rather than requiring infinite switching speed. This parameter adaptation approach achieves stability under load fluctuation with practical, implementable control complexity.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2733554B1Actuator control method and actuator control device
Publication Date: 2021.09.29 ISUZU MOTORS LTD
  • EP2733554B1 patent drawingFigure 1
  • EP2733554B1 patent drawingFigure 2~3
  • EP2733554B1 patent drawingFigure 4

AI summary

Time optimal control is used and there are provided: a calculation step of calculating a switching time t1 at which an acceleration output is switched to a deceleration output and an end time t2 of the deceleration output expressed by time elapsed from a calculation time t0 at which calculation for control is performed using a maximum acceleration αp and a maximum deceleration αm, which are measured in advance, at the time of the maximum output of control force of an actuator; and a control output step of setting the control force of the actuator to a maximum acceleration output from the calculation time t0 to the switching time t1, setting the control force of the actuator to a maximum deceleration output from the switching time t1 to the end time t2, and ending the output of the control force at the end time t2, and there is also provided an update step of calculating and updating the switching time t1 and the end time t2 by repeating the calculation step at each preset time. Due to this, there are provided an actuator control method and an actuator control device that incorporate the element of feedback control in time optimal control.