基于速度闭环的自适应力位控制算法

Adaptive force/position control algorithm with closed loop of velocity for the haptic device

摘要:

针对力觉主手力控制中接触刚度时变的特殊要求,提出了一种含有速度闭环的自适应力/位混合控制算法.通过构造系统特定的标量函数,证明可以通过选择合适的自适应参数更新律,使得在该控制律和更新律的共同作用下追踪力误差是有界的,力误差的导数是平方可积的.利用Barbalat引理证明了该控制算法具有全局渐近稳定性.给出了主手力控制系统的体系结构,并对不同频率正弦力信号进行了跟踪实验.实验结果表明:对于同样频率的力信号,所提出的方法跟踪误差小于常规阻抗控制方法,整个控制系统稳定并具有良好的控制特性.实验分析了控制律中各关键参数对控制品质的影响.

Abstract:

Aiming at the time-varying contact stiffness in haptic force/position control,an adaptive force/position control algorithm with closed loop of velocity is presented.Based on the definition of the specific scalar function of the system,the proper adaptive update law can be fixed.With the control law and update law,it can be proved that the error of tracking force is finite limit and its derivative function is square integrable. Then with Barbalat lemma the whole control algorithm is proved to be globally asymptotically stable.The architecture of hardware of the whole control system is given.The result of experiments of sinus force tracking shows that the tracking error of this algorithm is less than that of the normal impendence control algorithm at the same signal frequency.The whole control system is stable and has an excellent control quality.Effects of key parameters of the control law are also presented by analyzing the experimental results.