Shape Memory Alloy Actuator Resistance Control
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Solution Overview
Problem
Conventional shape memory alloy actuator systems face challenges in accurately and quickly determining the change point of resistance value, leading to inaccurate position control due to the time required for temperature stabilization during resistance value changes.
Innovation Solution
A shape memory alloy actuator system incorporating a resistance control circuit that includes a detecting section, calculating section, output section, and control section to rapidly calculate and apply electric current based on detected resistance values, allowing for precise position control by identifying key resistance values associated with unit temperature changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If temperature stabilization is waited for during resistance value measurement, then measurement accuracy is improved, but response time deteriorates
Solution Approach 1:
The system pre-stores the relationship between resistance values and temperatures in a lookup table before actual operation. This preliminary action allows the control device to quickly retrieve temperature information without waiting for temperature stabilization during runtime, thus improving response time while maintaining measurement accuracy through the pre-established relationship data.
Solution Approach 2:
The patent replaces the physical temperature stabilization process with an information-based solution. Instead of physically waiting for temperature to stabilize and then measuring, the system uses stored resistance-temperature relationship data to determine temperature from resistance measurements instantly, substituting a mechanical/thermal process with an information retrieval process.
2Speed
If change point search is performed quickly, then response time is improved, but measurement accuracy deteriorates due to unstable resistance values
Solution Approach 1:
The control device continuously monitors resistance values and compares them against the pre-stored relationship data to detect change points. This feedback mechanism allows the system to identify change points rapidly by detecting when resistance values deviate from expected patterns, while maintaining accuracy through continuous comparison with established reference data rather than relying on single unstable measurements.
Solution Approach 2:
The resistance-temperature relationship data is pre-stored in a lookup table before operation begins. This preliminary action enables the system to quickly compare real-time resistance measurements against known relationships to identify change points, achieving both fast detection speed and high accuracy without waiting for temperature stabilization during the search process.
3Ease of operation
If conventional temperature-based control is used, then position control is achieved, but system complexity increases due to temperature stabilization requirements
Solution Approach 1:
The patent substitutes the complex temperature-based control system with a resistance-based control system. By using the pre-stored resistance-temperature relationship data, the control device can determine position directly from resistance measurements without needing complex temperature stabilization mechanisms, thermal sensors, or temperature control hardware, thereby simplifying the overall system while maintaining position control capability.
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
Enables accurate and rapid determination of resistance change points, improving position control accuracy and controllability of the shape memory alloy actuator system, reducing the need for temperature stabilization and enhancing system responsiveness.
Implementation Method 1
a shape memory alloy wire of which, a length changes by being contracted due to heating by supplying an electric power, and by being elongated due to cooling
Implementation Method 2
heating by supplying an electric power
Implementation Method 3
a detecting section which detects a resistance value of the shape memory alloy wire when the shape memory alloy actuator contracts and elongates
Data Source
AI summary
A shape memory alloy actuator system includes a shape memory alloy actuator, a mobile object, an elastic member, a first regulating member, and a second regulating member, a detecting section which detects a resistance value of the shape memory alloy wire, a calculating section which calculates an electric current applied, an output section, a control section which controls the detecting section, the calculating section, the output section. The calculating section calculates a first resistance value at which, a proportion of a resistance change with respect to a change in a unit temperature changes from a first proportion to a second proportion which differs from the first proportion, and the control section carries out a position control of the shape memory alloy actuator by the first resistance value, when the shape memory alloy wire is to be elongated.