Abstract A variable stiffness mechanism is of great significance for simplifying the control scheme of a robot for a polishing process, which requires that the mechanism complies with the displacement variation along its axial axis while keeping the output force constant. To meet this demand, this paper addresses the design and optimization of a variable stiffness mechanism for producing constant output forces. The conceptual design of the variable stiffness mechanism is introduced, which is based on the principle of varying the effective length of a leaf spring. Then, the stiffness model of the mechanism is derived based on Euler-Bernoulli beam theory, in which the small sliding displacement of the leaf spring that affects the effective length is specifically addressed. For parameter optimization, a nonlinear multiobjective optimization problem is formulated to achieve a larger range of stiffness variation and higher transmission efficiency. Utilizing the optimized design parameters, a finite element analysis model and a prototype of the variable stiffness mechanism are developed. The effectiveness of the proposed stiffness model and the validity of the designed variable stiffness mechanism are demonstrated by numerical simulations and experimental studies.

中文翻译：

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用于产生恒定输出力的变刚度机构的概念设计和参数优化

摘要 变刚度机构对于简化机器人抛光过程的控制方案具有重要意义，这要求该机构在保持输出力恒定的同时，顺应其轴向位移变化。为了满足这一需求，本文讨论了用于产生恒定输出力的可变刚度机构的设计和优化。介绍了变刚度机构的概念设计，它基于改变板簧有效长度的原理。然后，基于欧拉-伯努利梁理论推导了机构的刚度模型，其中特别解决了影响有效长度的板簧的小滑动位移。对于参数优化，制定了非线性多目标优化问题，以实现更大范围的刚度变化和更高的传输效率。利用优化后的设计参数，开发了有限元分析模型和变刚度机构原型。数值模拟和实验研究证明了所提出的刚度模型的有效性和设计的可变刚度机构的有效性。