Compliant joints can provide safer physical human–robot interaction. To effectively balance the response bandwidth and output impedance, variable stiffness joints have been studied by many researchers. Leaf spring-based variable stiffness joint (LSVSJ) has the advantages of easy construction and large stiffness range. This article presents the design and validation of a novel LSVSJ with reconfigurability (LSJR). Compared with most of the existing LSVSJ, this novel LSJR ensures the contact performance between the roller and the leaf spring, uses a novel effective length adjustment mechanism, and provides multiple stiffness ranges. The compliance of the LSJR is generated by leaf springs. The spring is bent by two rows of rollers integrated on an adjustable slider, where the distance between the rollers can be changed so as to achieve a tighter contact between the roller and the spring. The effective length of the spring can be adjusted by changing the position of the slider locating at the intersection between a straight rail and an arcuate rail. A reconfigurable number of leaf springs provide six different stiffness ranges (e.g., 138.55–396.08 N·m/rad for single leaf spring, and 384.56–1222.60 N·m/rad for a combination of three leaf springs). By integrating a high-resolution angle sensor, the LSJR can also measure the joint torque. Moreover, the hollow shaft structure of the joint is beneficial for passing cables through it. Experiments were performed to measure the stiffness of the LSJR under different configurations, validate its efficacy in unexpected collisions, and investigate its potential to be a one-degree-of-freedom torque sensor.

中文翻译：

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具有可重构性的新型板簧变刚度接头的设计与验证

合规的关节可以提供更安全的人机交互。为了有效地平衡响应带宽和输出阻抗，许多研究人员已经研究了可变刚度接头。基于板簧的可变刚度接头（LSVSJ）具有易于构造且刚度范围大的优点。本文介绍了具有可重新配置性（LSJR）的新型LSVSJ的设计和验证。与大多数现有的LSVSJ相比，这种新颖的LSJR确保滚子和板簧之间的接触性能，使用新颖的有效长度调节机制，并提供多个刚度范围。LSJR的柔顺性是由板簧产生的。弹簧由集成在可调滑块上的两排滚子弯曲，可以改变滚子之间的距离，从而使滚子和弹簧之间的接触更紧密。弹簧的有效长度可以通过改变位于直线导轨和弧形导轨之间的交点处的滑块的位置来调节。可重新配置的板簧数量提供了六个不同的刚度范围（例如，单板簧为138.55–396.08 N·m / rad，三个板簧的组合为384.56–1222.60 N·m / rad）。通过集成高分辨率角度传感器，LSJR还可以测量关节扭矩。此外，接头的空心轴结构有利于使电缆穿过接头。进行实验以测量LSJR在不同配置下的刚度，验证其在意外碰撞中的功效，