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Hard-Stop Synthesis for Multi-Degrees-of-Freedom Compliant Mechanisms
Dean Chen1, Armin Pomeroy1, Brandon T Peterson1
1Department of Mechanical and Aerospace Engineering, University of California, Los Angeles, 420 Westwood Plaza, Los Angeles, CA 90095.
Journal of Mechanical Design (New York, N.Y. : 1990)
|August 15, 2026
Summary
This study introduces a novel design method for compliant mechanisms, enhancing overload protection with integrated multi-DOF motion limits. This innovation prevents mechanical failure in complex applications, paving the way for wider real-world use.
Area of Science:
- Mechanical Engineering
- Materials Science
- Biomechanics
Background:
- Compliant mechanisms offer precision motion but are prone to fatigue and failure.
- Real-world applications require robust overload protection, especially under uncertain loads.
- Conventional hard stops limit multi-DOF (degree-of-freedom) systems excessively.
Purpose of the Study:
- To develop a systematic design method for overload protection in compliant mechanisms.
- To integrate coupled multi-DOF motion limits into compact hard-stop surfaces.
- To optimize hard-stop geometry for maximum working space while ensuring safety.
Main Methods:
- Developed a theoretical and practical framework for hard-stop design synthesis.
- Optimized contact surface geometry for compliant mechanisms.
- Applied the method to a caged-hinge mechanism for orthopaedic implants.
- Validated the design through numerical and experimental analysis.
Main Results:
- Achieved reliable overload protection against fatigue, yielding, and buckling.
- Maximized the multi-DOF working space of the compliant mechanism.
- Demonstrated the effectiveness of integrated coupled motion limits.
- Validated the design's performance in a relevant orthopaedic application.
Conclusions:
- The proposed design synthesis method enables robust overload protection in compliant systems.
- This work provides a foundation for precision hard-stop design in compliant mechanisms.
- Enables wider application of compliant mechanisms in real-world scenarios with uncertain loads.
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