Tang, Y., He, M., Wang, Z.-P., & Xia, L. (2026). Nonlinear topology optimization design of compliant mechanisms with tailored input/output stiffness. Mechanism and Machine Theory, 219, 106330. https://doi.org/10.1016/j.mechmachtheory.2025.106330
Abstract:
Topology optimization of compliant mechanisms (CMs) typically seeks to maximize input stiffness while minimizing output stiffness to achieve optimal geometric advantage (GA). However, simultaneously tailoring input and output stiffness inherently conflicts with these objectives, a challenge that is exacerbated under nonlinear conditions. To address this, we propose a nested optimization framework incorporating geometric and material nonlinearities, which decouples the problem into two levels: the outer loop maximizes GA, while the inner loop enables precise input/output stiffness customization. An adaptive volume control strategy is further introduced to suppress hinge-like features and improve material efficiency. Numerical examples demonstrate that the method yields hinge-free topologies with input and output stiffness closely matching the targets. Finally, a series of CMs with varying stiffness ratios were designed and fabricated. Experimental results confirm the effectiveness of proposed method in tailoring input/output stiffness, while verifying the output-end resistance to external excitations and the required input actuation force. The method is applicable to mechanisms with specific performance demands, such as low-actuation, high-output-stability robotic grippers and medical instruments with both high input and output stability.
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Funding Info:
This research / project is supported by the Agency for Science, Technology and Research - RIE2025 Manufacturing, Trade And Connectivity (MTC) Programmatic Fund - 4D Additive Manufacturing (4DAM) of Smart Structures
Grant Reference no. : M24N3b0028
This research / project is supported by the Agency for Science, Technology and Research - Start-up Fund
Grant Reference no. : N.A.