Shape Memory Alloy Actuator Oscillation Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional shape memory alloy actuators using resistance feedback control for position control of a moving body suffer from oscillation issues when the resistance of the alloy approaches a target value, making it difficult to completely restrain the moving body's position.
Innovation Solution
A shape memory alloy actuator design that incorporates a fixed member, a moving body pushing member, first and second bias members, and stoppers to mechanically restrain the moving body's position by utilizing the shape change of the alloy due to temperature changes, ensuring the moving body is kept stationary at predetermined positions without being affected by oscillations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If resistance feedback control is used to control the position of a moving body, then the position control function is achieved, but oscillation occurs when the resistance approaches the target resistance
Solution Approach 1:
A moving body pushing member is introduced as an intermediary mechanical element between the shape memory alloy and the moving body. This mediator transmits the shape change force while allowing mechanical restraint through stoppers, separating the control function from the positioning function to eliminate oscillation
Solution Approach 2:
Stoppers are pre-positioned to mechanically restrain the moving body at predetermined positions before oscillation can occur. This preliminary mechanical constraint prevents the oscillation that would otherwise occur during resistance feedback control
2Speed
If the moving body is continuously in contact with the moving body pushing member, then the actuator can respond to shape changes, but oscillation is transmitted to the moving body
Solution Approach 1:
The contact state between the moving body and pushing member is made dynamic rather than static. The moving body can be in contact during normal operation for responsive actuation, but can be separated when mechanical restraint is applied, allowing the system to adapt its coupling state based on operational requirements
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
Effectively prevents oscillation of the moving body by mechanically restraining its position, allowing precise control and stability in position maintenance, even when the shape memory alloy's resistance approaches a target value.
Implementation Method 1
A shape memory alloy changes its shape with phase transformation caused by a change in the temperature
Implementation Method 2
a first bias member that exerts an external force on the moving body pushing member in a direction opposite to a direction of change in the shape of the shape memory alloy caused by heating, a second bias member that exerts an external force on the moving body in a direction same as the direction of change in the shape of the shape memory alloy caused by heating
Data Source
AI summary
To provide a shape memory alloy actuator using a shape memory alloy that mechanically restrains a moving body in position to prevent oscillation, the actuator has a moving body pushing member adapted to be capable of abutting to the moving body, a bias spring for the moving body pushing member that exerts an external force on the moving body pushing member in the direction opposite to the direction of change in the shape of a shape memory wire caused by heating, a bias spring for the moving body that exerts an external force on the moving body in the direction same as the direction of change, a first stopper that restricts the movement of the moving body to a predetermined position upon cooling. One end of the shape memory wire is fixed, the other end is mechanically linked with the moving body pushing member. The moving body pushing member and the moving body are moved by deformation caused by heating, and the moving body and the moving body pushing member are separated, when the moving body is stopped at the position of the first stopper.