基于交叉四杆机构的变刚度执行器优化设计与仿真验证
Optimization Design and Simulation Validation of a Variable Stiffness Actuator Based on a Crossed Four-Bar Mechanism
AI总结：
本文提出一种基于交叉四杆柔性单元的拮抗变刚度执行器，通过多目标优化实现轻量化与低惯量，仿真验证其扭矩精度与可行性。
AI中文摘要：
本文提出了一种基于两个交叉四杆柔性传动弹性单元（CFB-CTEs）的生物启发式拮抗变刚度执行器（VSA）。该设计解决了拮抗式VSA机构中非线性弹性整形与低结构惯性相结合的难题。受膝关节屈曲过程中前、后交叉韧带交叉约束行为的启发，所提出的执行器利用几何传动、弹性储能和双侧拮抗布置来塑造输出扭矩和等效刚度。建立了多目标优化模型，以平衡扭矩跟踪精度、等效惯量和质量。选定的折中设计方案实现了扭矩均方根误差（RMSE）为$0.883~\text{N·mm}$，总质量为$50.2~\text{g}$。与仅以扭矩为目标的独立优化设计相比，其平均等效惯量降低了约78%。进一步建立了ADAMS多体模型，以验证在单输入、对向输入和同向输入条件下的结构响应。结果支持所提出的交叉四杆弹性单元作为拮抗式VSA的轻量化非线性弹性分支的可行性。
英文摘要：
This paper presents a bio-inspired antagonistic variable stiffness actuator (VSA) based on two crossed four-bar compliant transmission elastic units (CFB-CTEs). The design addresses the difficulty of combining nonlinear elastic shaping with low structural inertia in antagonistic VSA mechanisms. Inspired by the crossed constraint behavior of the anterior and posterior cruciate ligaments during knee flexion, the proposed actuator uses geometric transmission, elastic energy storage, and bilateral antagonistic arrangement to shape the output torque and equivalent stiffness. A multi-objective optimization model is established to balance torque tracking accuracy, equivalent inertia, and mass. The selected compromise design achieved a torque root-mean-square error (RMSE) of $0.883~\mathrm{N\,mm}$ and a total mass of $50.2~\mathrm{g}$. Its average equivalent inertia was reduced by about 78% compared with an independent torque-only optimized design. An ADAMS multibody model was further built to verify the structural response under single-input, opposite-input, and same-input conditions. The results support the feasibility of the proposed crossed four-bar elastic unit as a lightweight nonlinear elastic branch for antagonistic VSAs.
