基于虚拟弹簧的欠驱动手指的动力学建模和控制

Virtual spring based dynamic model and control of underactuated hand

采用虚拟弹簧对2关节欠驱动手指进行了动力学建模。并使用该方法建立实际的3关节欠驱动手指的动力学模型,通过动态控制实验验证了动力学模型的正确性。该方法不仅避免了求解微分几何方程,并且直接派生出可解耦的动力学模型。可直接进行逆动力学分析、仿真和实时控制。同时,建立了基于动力学模型的速度观测器,用于轨迹跟踪,弥补了欠驱动手没有速度传感器的缺点,补偿了欠驱动环节造成的不确定因素。与PID或计算力矩法相比较,其轨迹跟踪误差更小,动态控制效果更好。

A dynamic model was established for the underactuated 2-joint finger using the virtual spring approach,and a dynamic model for the underactuated 3-joint finger was deduced hereform.The dynamic models were verified by dynamic control experiments.The suggest approach not avoids the solution of the differential-geometrical equations,but also leads to a completely decoupled dynamic model which is ideal for the inverse dynamic analysis,simulation and real-time control directly. Meantime,a velocity observer was constructed based on the dynamic model to track the trajectory to make up the drawback of short of velocity sensors in the underactuated hand and the uncertain factors by the underactuated links.Comparing with the PID control or the control by the computed torque method,the observer is characterized by less trajectory tracking error and better dynamic control results.