Modular SMA Actuator with Nested Wires for Extended Displacement
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Solution Overview
Problem
Existing shape memory alloy (SMA) actuator systems are limited by their short actuation distance and slow cooling times, which restrict their power and efficiency, especially in applications requiring compact designs with limited installation space.
Innovation Solution
A modular actuator system comprising multiple shaft elements and blade elements with SMA wires, where the blade elements are arranged to allow for rotational and non-rotational mounting configurations, enabling increased actuation distances and faster cooling through the use of dual SMA wires and resilient elements, while maintaining a compact design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If SMA wires with large diameters are used to increase actuator power, then the actuator becomes more powerful, but the cooling time increases significantly
Solution Approach 1:
The patent divides the single large-diameter SMA wire into multiple smaller-diameter SMA wires (first SMA wire and second SMA wire). This segmentation allows each wire to cool down faster while collectively providing the same or greater actuation force, thus resolving the contradiction between power and cooling time.
Solution Approach 2:
The patent arranges the first and second SMA wires in a nested configuration where they are positioned concentrically or in close proximity. This nesting allows both wires to share the same thermal environment and cooling pathways, maximizing the cooling efficiency while maintaining compact spacing that preserves actuation power.
2Volume of moving object
If the actuator design is made compact to fit limited installation space, then the installation space requirement is reduced, but the actuation distance is limited
Solution Approach 1:
The patent transitions from a single-linear SMA wire arrangement to a multi-dimensional configuration with multiple SMA wires arranged at different positions and orientations. By adding the second SMA wire in a different spatial dimension (nested or parallel arrangement), the system achieves extended actuation distance through combined displacement while maintaining a compact overall volume.
Solution Approach 2:
The patent combines the actuation effects of multiple SMA wires (first SMA wire and second SMA wire) to achieve greater total actuation distance. The blade element integrates the mechanical output of both wires, merging their individual contributions into a coordinated rotational movement that extends the effective actuation range within a compact footprint.
3Device complexity
If a single SMA wire is used to simplify the actuator design, then the device complexity is reduced, but the actuation distance is limited
Solution Approach 1:
The blade element is designed as a multi-functional component that serves multiple purposes: it is mounted on the shaft element, holds both the first and second SMA wires, and converts the linear contraction of the SMA wires into rotational movement. This universal blade element integrates multiple functions into a single component, adding minimal complexity while enabling extended actuation distance through coordinated wire activation.
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 modular design provides a powerful actuator system with extended actuation distances and rapid cooling, enhancing efficiency and adaptability to various applications with limited space constraints.
Implementation Method 1
at least three shape memory alloy, SMA, wires to connect the blade elements with each other and a fixed position
Implementation Method 2
use the memory effect of SMA material that can be transitioned back and forth between an activated and a deactivated shape
Implementation Method 3
The actuator system may further comprise at least one resilient element
Data Source
AI summary
The present invention relates to a modular actuator system including at least two shaft elements arranged parallel to each other and extending in a first direction, at least two blade elements mounted on each shaft element in different horizontal levels substantially perpendicular to the first direction, with all blade elements mounted on one of the shaft elements being fixedly secured thereto, whereas at least one of the blade elements mounted on another shaft element can rotate around the axis of this other shaft element, and at least three SMA wires to connect the blade elements with each other and a fixed position, with power being supplied to one of the SMA wires leading to a rotation of all blade elements.