Contraction-Type Gel Actuator Displacement Control via Feedback
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Solution Overview
Problem
Contraction-type gel actuators face challenges in achieving high-precision control due to their hysteresis characteristics, which affect the accuracy of displacement control, limiting their application in position control and other precise operations.
Innovation Solution
A feedback control method is implemented using the equation E=kp(xd−x)+Ed, where E is the applied voltage, xd is the target displacement, Ed is obtained through linear approximation of voltage and displacement measurements, and kp is the proportional gain, to accurately control the displacement of the gel actuator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If feedback control is implemented to achieve high-precision displacement control, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The patent implements feedback control by measuring the actual displacement of the gel actuator and comparing it with the target displacement, then adjusting the applied voltage based on the error signal. This closed-loop control system continuously monitors and corrects displacement errors, achieving high-precision control despite the hysteresis characteristics of the gel material.
Solution Approach 2:
The patent changes the control parameter from direct voltage control to error-based voltage adjustment. By using the displacement error (difference between target and actual displacement) as the control parameter, the system adapts to the hysteresis behavior of the gel actuator and achieves accurate positioning through dynamic parameter adjustment.
2Ease of operation
If linear approximation is used to simplify the voltage-displacement relationship, then ease of operation is improved, but manufacturing precision deteriorates
Solution Approach 1:
The feedback mechanism compensates for the inaccuracies introduced by linear approximation. By continuously measuring actual displacement and adjusting voltage based on the error between target and actual positions, the system maintains high precision despite using a simplified linear control equation rather than a complex nonlinear model.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The feedback control method effectively achieves high-accuracy displacement control, enabling the contraction-type gel actuator to be used in precise position control applications by accounting for its hysteresis characteristics.
Implementation Method 1
a gel that is driven by an effect of electric field is sandwiched with a mesh-type anode and a foil-type cathode. When a voltage is applied between the electrodes, the gel is drawn into a gap of the mesh of the anode.
Implementation Method 2
the contraction-type gel actuator has a hysteresis characteristic in the relationship between the applied voltage and the displacement, when the applied voltage is gradually increased and then gradually lowered.
Data Source
AI summary
A method for controlling a displacement in the thickness direction of the contraction-type gel actuator having an effect of contraction in the thickness direction by applying a voltage between an anode and a cathode between which a gel which includes a dielectric polymeric material is interposed, which includes performing feedback control of an applied voltage, with a sampled value of a displacement when the applied voltage acts on the contraction-type gel actuator, according to the following equation (1):E=kp(xd−x)+Ed (1)In the equation, xd represents a target displacement of the contraction-type gel actuator; Ed represents an applied voltage with respect to the target displacement xd obtained by the linear approximation of the applied voltage and the displacement from a measured result of the displacement in accordance with the applied voltage of the contraction-type gel actuator; and kp represents a proportional gain.