非完全对称气动柔性弯曲关节力学特性实验

Experimental Study on Mechanical Properties of Flexible Pneumatic Bending Joint

为改进柔性机器人驱动器结构及数学模型,提出了一种非完全对称气动柔性弯曲关节及其数学模型。为了实现其实时闭环控制系统,进一步简化了原有数学模型,并对其力学特性进行了实验研究。搭建了力学特性实验平台,并对两种不同规格(长度分别为40、60 mm)的关节进行了测试。采用Matlab曲线及曲面工具箱对测试结果进行分析,得到了新型气动柔性弯曲关节的经验模型。该经验模型表明气动柔性弯曲关节的弯曲角度与初始长度、关节内外气压差、输出力之间存在非线性关系。与简化的数学模型比较,该经验模型具有更高的精度,其中输出角度模型相对误差平均值小于6.7%,输出力模型相对误差平均值小于2%。同时,该经验模型纠正了原有数学模型中,认为关节初始长度与弯曲角呈正比的错误结论。

A new type of flexible pneumatic bending joint （FPBJ） and its mathematical model were proposed. To implement its real-time closed-loop control system, its mathematical model was simplified, and the mechanical characteristics were studied experimentally. An experimental platform for mechanical characteristics testing was set up, and two FPBJs with different length（40 mm and 60 mm） were tested. The experimental results were analyzed with Matlab curve and surface fitting toolbox, and the FPBJ empirical model was derived. The model showed a non-linear relationship among the bending angle, the FPBJs internal and external pressure difference, joint length and the output force of the FPBJs. Contrast to the simplified mathematical model, the empirical model was more precise, the mean relative error of output angle model was less than 6.7% , and the mean relative error of output force model was less than 2%. Meanwhile, an error, the joint length is proportional to the bending angle in the mathematical model, was avoided in the empirical model.