Variable Stiffness Actuator With Segmented Conductive Wires
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Solution Overview
Problem
Existing variable stiffness actuators for flexible members, such as endoscopes, lack efficient control over bending stiffness changes, leading to suboptimal performance in adapting to external forces and environments.
Innovation Solution
A variable stiffness actuator comprising a shape-memory member and a heater, with conductive wires of varying thickness and resistance to improve responsiveness by efficiently supplying power and controlling phase transitions, allowing for precise adjustment of stiffness states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a single uniform conductive wire is used to supply power to the heater, then the structure is simple, but the power supply efficiency is insufficient and responsiveness is poor
Solution Approach 1:
The conductive wire is divided into two distinct segments: a first conductive wire with higher electrical resistance per unit length and a second conductive wire with lower electrical resistance per unit length. This segmentation allows different portions of the power supply system to perform optimized functions, improving overall power supply efficiency and responsiveness without excessive complexity
Solution Approach 2:
Different sections of the power supply system are assigned different electrical resistance characteristics. The first conductive wire (with higher resistance) is positioned in specific locations while the second conductive wire (with lower resistance) is positioned in other locations, creating local quality variations that optimize power distribution and heat generation where needed
2Manufacturing precision
If power is supplied inefficiently to the heater, then the structure remains simple, but the bending stiffness control precision is poor
Solution Approach 1:
The electrical resistance parameter of the conductive wire is changed by using two different types of wires with distinct resistance characteristics. This parameter change enables more efficient power supply to the heater, which in turn provides precise control over the bending stiffness of the flexible member through controlled phase transition
3Adaptability or versatility
If the heater cannot efficiently control phase transition, then the system remains simple, but the adaptability to external forces is poor
Solution Approach 1:
The power supply system is designed to dynamically control the phase transition of the shape-memory member by efficiently supplying power to the heater. This enables the flexible member to dynamically adapt its bending stiffness in response to external forces, improving adaptability while maintaining reasonable system complexity
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 solution enables improved responsiveness and precise control over bending stiffness, enhancing the actuator's ability to adapt to external forces and environments, thereby optimizing the performance of flexible members like endoscope insertion sections.
Implementation Method 1
a heater configured to receive power to heat the shape-memory member so as to cause the shape-memory member to change from a first phase as a low stiffness state to a second phase as a high stiffness state
Implementation Method 2
an inducing member causes the shape-memory member to undergo a phase transition by virtue of the power (current) supplied to the inducing member from a power supply section
Data Source
AI summary
A variable stiffness actuator includes a shape-memory member, and a heater configured to receive power to heat the shape-memory member so as to cause the shape-memory member to change from a first phase as a low stiffness state to a second phase as a high stiffness state showing a higher stiffness than the low stiffness state. The actuator also includes a first conductive wire having one end connected to the heater and constituting a part of a power supply line for the heater, and a second conductive wire having one end connected to the other end of the first conductive wire, thicker than the first conductive wire, and having an electrical resistance per unit length lower than that of the first conductive wire.