Multi-DOF Hard-Stop Design for Compliant Mechanisms

Compliant mechanisms offer precise contactless motion control for applications ranging from robotics to biomedical devices. However, their translation to applications is constrained by inherent vulnerability to fatigue and mechanical failure under complex, uncertain service loads. Traditional hard-stop solutions, built from stacked single-DOF limits, impose overly restrictive protection to multi-DOF motion, limiting device performance and increasing wear risk. In this project, we propose a systematic design framework for integrated multi-DOF overload protection, embedding coupled motion limits into a single pair of compact hard-stop surfaces. The framework combines analytical modeling with shape optimization of the contact geometry to preserve elastic operation while maximizing workspace. By shifting from conservative, segmented stops to a unified design, this method paves the way for robust, high-performance compliant systems capable of safely operating under unpredictable loading, accelerating their translation into demanding real-world environments.

  • Project Lead: Dean Chen
  • Surgical Collaborator: Drs. Nelson SooHoo and Alexandra Stavrakis (Orthopaedic Surgery, UCLA)
  • Project Team: He Kai Lim, Brandon Peterson, WIll Flanagan, Armin Pomeroy, Prof. Jonathan B. Hopkins

Relevant Publications

  • Chen, D., Pomeroy, A., Peterson, B.T., Flanagan, W., Lim, H.K., Stavrakis, A., SooHoo, N.F., Hopkins, J.B., & Clites, T.R., Hard-Stop Synthesis for Multi-DOF Compliant Mechanisms. Journal of Mechanical Design. (under review)