软体手臂刚度特性分析

气动肌肉驱动的软体机器人具有质量轻、功率密度比高、人机交互安全性高等优点。提出了一种由伸长型及收缩型气动肌肉组成的变刚度软体机器人手臂,能够实现位置与刚度的解耦。针对单根收缩型及伸长型气动肌肉进行了刚度测试实验,利用最小二乘法建立了单根气动肌肉气压、位移及刚度关系模型。基于所建立的单根气动肌肉刚度模型,针对所设计的软体手臂,建立了手臂刚度模型。搭建了手臂刚度测试实验平台,通过实验验证可知理论模型与实验模型的刚度变化趋势一致,平均相对误差为3.60%,最大相对误差为6.17%。

Analysis of Stiffness Characteristics of Soft Arm

Soft robot arm driven by pneumatic artificial muscles can possess the ability of high ratio of power to weight, important for performance and light weight, and a vital component of the inherent safety approach to physical human-robot interaction. One of the main drawbacks of pneumatically actuated soft arm is that their stiffness cannot be varied independently from their position in space. Based on these reasons, a novel variable stiffness soft robotic arm composed of both three contractile and one extensor pneumatic artificial muscles was presented. This arm combined the light weight, high ratio of power to weight and robustness of pneumatic actuation with the adaptability and versatility, and stiffness can be adjusted independently of its length. Experiment platform of single contractile and extensor pneumatic artificial muscles was setup, and the static characteristic was identified for contractile and extensor pneumatic artificial muscles through quasi-static experiments. By using the least square method, the relational model of pressure, distance and stiffness for single contractile and extensor pneumatic artificial muscles was established. In order to analyze the stiffness characteristic of this arm, stiffness model of the designed soft arm was established. Stiffness experiment platform of this soft arm was setup. Experiment data was compared with theoretical model, and they possessed the same trend, the mean relative error was 3.60%, and the maximum relative error was 6.17%.