为了使假手能够完成对不同刚性物体的柔顺抓取,提出了一种带有刚度模糊观测的反演控制策略,以满足假手在自由空间内的速度比例控制和在约束空间内的柔性握力控制,两个控制过程采用同一个反演控制器实现.设计了轨迹规划器,对假手的期望开合速度、握力进行规划,将速度控制和握力控制转换为位置控制;设计了基于位置的反演控制器,并采用李亚普诺夫稳定性理论证明了该反演控制器的稳定性;设计了刚度模糊观测器,实时调整假手模型参数,均衡被抓握物体对假手控制策略的影响,并实现假手在自由空间和约束空间控制过程的过渡.对所提出的控制策略进行了实验验证,实验结果证明了该控制策略的有效性.
In order to make the prosthetic hand complete compliant grasp of different rigid objects, a prosthetic hand control strategy based on fuzzy observation of stiffness is proposed to meet the needs of the speed ratio control in free space and the grip force flexible control in constraint space. Both control process are realized by the same backstepping controller. The expected opening and closing speed, and grip strength are planned by the designed trajectory planner. The conversion from the speed control and the grip force control to the position control is realized. The position backstepping controller is designed and its stability is proved based on Lyapunov stability theory. The designed fuzzy stiffness observer adjusts the parameters of the model in real time, balances the influence of the grasped objects on the control strategy, and switches the control process between free space and constraint space. The control strategy is verified by experiments, and the effectiveness of the control strategy is proved.