张庭, 姜力, 刘宏. 仿生假手抓握力控制策略[J]. 机器人, 2012, 34(2): 190-196. DOI: 10.3724/SP.J.1218.2012.00190
引用本文: 张庭, 姜力, 刘宏. 仿生假手抓握力控制策略[J]. 机器人, 2012, 34(2): 190-196. DOI: 10.3724/SP.J.1218.2012.00190
ZHANG Ting, JIANG Li, LIU Hong. A Grasping Force Control Strategy for Anthropomorphic Prosthetic Hand[J]. ROBOT, 2012, 34(2): 190-196. DOI: 10.3724/SP.J.1218.2012.00190
Citation: ZHANG Ting, JIANG Li, LIU Hong. A Grasping Force Control Strategy for Anthropomorphic Prosthetic Hand[J]. ROBOT, 2012, 34(2): 190-196. DOI: 10.3724/SP.J.1218.2012.00190

仿生假手抓握力控制策略

A Grasping Force Control Strategy for Anthropomorphic Prosthetic Hand

  • 摘要: 为了使仿生假手完成各种精细作业,提出一种抓握力控制策略. 在自由空间和约束空间中分别使用基于位置的阻抗控制和力跟踪阻抗控制. 在过渡过程中使用模糊观测器切换控制模式.两种控制模式采用同一个基于位置的阻抗控制器, 在约束空间向阻抗控制器中引入参考力,以满足约束空间的抓握力控制要求.这种方法可 以使关节在自由空间和约束空间中分别实现良好的轨迹跟踪和力矩跟踪,在过渡过程中实 现控制模式的可靠切换和系统的稳定过渡.提出一种自适应滑模摩擦力补偿方法,利用终 端滑模思想设计了滑模函数,使得系统跟踪误差在有限时间内收敛,避免了传统线性滑模 面状态跟踪误差无法在有限时间内收敛至0的问题.根据指数形式摩擦力的特点,利用终端 滑模控制思想获得包含摩擦力参数估计的滑模控制律,并基于李亚普诺夫稳定性定理推导了估计参 数的在线自适应律. 对该抓握力控制策略在HIT假手上进行了抓取实验,实验结果证明了控制策略的有效性.

     

    Abstract: A grasping force control strategy is proposed in order to complete various fine manipulations by using anthropomorphic prosthetic hand. The position-based impedance control and force-tracking impedance control are used in free and constrained spaces, respectively. The fuzzy observer is adopted in transition in order to switch control mode, and a same position-based impedance controller is used in those two control modes. In order to achieve grasping force control, a reference force is added to the impedance controller in the constrained space. Trajectory tracking in free space and torque tracking in constrained space are realized, and reliability of mode switch and stability of system are achieved in transition. An adaptive sliding mode friction compensation method is proposed. The terminal sliding mode idea is used to design sliding mode function, which makes the tracking error converge to zero in finite time and avoids the problem of conventional sliding surface that the state tracking error can not converge to zero in finite time. Based on the characteristic of the exponential form friction, the sliding mode control law including the estimation of friction parameter is obtained through terminal sliding mode idea, and the on-line parameter update laws are obtained based on Lyapunov stability theorem. The experiments on the HIT prosthetic hand IV are carried out to evaluate the grasping force control strategy, and the experiment results verifies the effectiveness of this control strategy.

     

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