Spacecraft Payload Alignment Using Shape Memory Alloy Wires
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Solution Overview
Problem
Existing devices for holding and aligning optical or thruster components in space travel are prone to errors, complex, and require extensive testing due to their weight and reliance on stepping motors and sensors, making them costly and inefficient.
Innovation Solution
A device using shape memory alloy wires as actuators, where the resistance change during phase transformation is used as a control variable to adjust the position of the components, eliminating the need for additional sensors and reducing complexity by leveraging the inherent properties of the wires for position determination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If stepping motors and optical sensors are used for positioning, then positioning precision is improved, but device weight increases significantly
Solution Approach 1:
The patent removes optical sensors and complex positioning systems from the device. Instead, it uses the inherent resistance properties of shape memory alloy wires themselves to determine position, extracting only the essential function needed while eliminating unnecessary components that add weight.
Solution Approach 2:
The shape memory alloy wires serve dual functions: they act as both actuators (providing mechanical force through phase transformation) and as position sensors (through their inherent resistance changes). This self-service capability eliminates the need for separate sensing components, reducing overall device weight while maintaining positioning precision.
2Ease of operation
If multiple stepping motors and gears are used for alignment, then alignment capability is improved, but device complexity increases
Solution Approach 1:
The patent extracts and removes gears, multiple motors, and complex transmission mechanisms from the alignment system. It replaces them with a simplified configuration using only shape memory alloy wires that directly adjust component positions through their phase transformation properties.
Solution Approach 2:
The patent replaces the mechanical system of gears and multiple stepping motors with a smart material-based system. The shape memory alloy wires use electro-thermo-mechanical phase transformation to achieve alignment, substituting complex mechanical transmissions with a more integrated and controllable material-based actuation mechanism.
3Measurement precision
If conventional positioning systems with multiple components are used, then positioning accuracy is improved, but the number of components and testing requirements increases
Solution Approach 1:
The patent merges the actuator function and the sensing function into a single component - the shape memory alloy wire. By combining these functions that were previously performed by separate components (motors and sensors), the system achieves positioning accuracy with fewer total components, reducing testing requirements while maintaining precision.
4Weight of moving object
If shape memory alloy wires are used as actuators, then device weight is reduced, but control precision must be maintained
Solution Approach 1:
The patent implements a control loop that uses the resistance behavior of the shape memory alloy wires as feedback. By continuously monitoring resistance changes and using this information to adjust the actuation, the system maintains precise control despite using lightweight shape memory alloy wires instead of heavier traditional actuators with built-in sensors.
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
This solution results in a lightweight, scalable, and reliable system with reduced complexity, enabling precise alignment and maintenance of components without the need for extensive testing, and allows for efficient use of mechanical energy in a compact space.
Implementation Method 1
The tilting device comprises a number of wires made of a shape memory alloy as an actuator
Implementation Method 2
The change in the specific resistance of the number of wires during the phase transformation from martensite to austenite
Implementation Method 3
The invention thus proposes using the electro-thermo-mechanical behavior of a number of wires made of a shape memory alloy (SMA) as a motor or actuator. The resistance behavior of the shape memory alloy is fed back as a control variable in a control loop
Data Source
Figure 1~2
Figure 3~4
Figure 5a~5b
AI summary
The invention relates to a device for holding and aligning a user component, in particular an optical element or an electrical or chemical thrust nozzle. The device comprises a first and a second housing part (1, 2) and a tilting device (36). The first housing part (1) is configured at a first end (18) for stationary mounting on a support, in particular a spacecraft. The second housing part (2) is configured at a second end (19) for connection with the user component. The first end (18) and the second end (19) are located on opposite sides of the device with respect to a longitudinal axis (17).The tilting device (36) mechanically connects the first and second housing parts (1, 2) and enables a defined alignment and holding of the relative position of the second housing part (2) relative to the first housing part (1), wherein the tilting device (36) as an actuator comprises a number of wires (6, 7, 16) made of a shape memory alloy, wherein the length of each of the number of wires (6, 7, 16) is individually adjustable by a respective determination of the resistance, which can be processed as a controlled variable in a control loop.