气动肌肉的三元素模型辨识研究

摘要

基于Reynolds所提出的气动肌肉三元素模型理论,通过实验对自制的气动肌肉进行了模型参数辨识,结果表明三元模型的有效力系数F与压力P呈近似线性关系,弹簧系数K与压力P呈近似的分段线性关系,且随P的增加先减小后增大.因此,采用分段模型对Reynolds三元素模型进行了改进.考虑到阻尼系数B数值相对较小,对气动肌肉动力学方程的贡献较小,改进的模型采用有界的函数来表示阻尼系数B.最终,设计了两种不同的滑模控制方法,通过控制实验证明了辨识模型的有效性.%Based on the three-element model for pneumatic muscle (PM) proposed by Reynolds,the experiments were conducted to identify the parameters of the PM model.The experimental results demonstrate that the contractile element Fce increases linearly with the pressure P,but a piecewise linear relationship is shown between the pressure P and the spring factor K,which rises up first and then declines with respect to the consistent increase of the pressure P.Therefore,the improved segmented three-element model was used to describe the PM model.In consideration of the small effect on the output force of PM,the damping factor B was treated as a bounded function.Finally,two different sliding mode controllers were designed and the control experiments demonstrated the effectiveness of the proposed model.