多自由度遥操作机器人可靠性控制研究

Reliable control for tele-robotics with multi degree of freedom

本文针对多自由度遥操作机器人的可靠性控制问题进行了研究,采用时延估计在线获得机器人系统的未知动力学和外界干扰,并在控制过程中加以补偿.这里,我们利用一些满足一定概率分布的不相关的随机变量来表示遥操作机器人的概率性执行器故障.通过考虑遥操作机器人的概率性执行器故障和控制时变时延,我们建立了新的遥操作机器人模型.在此基础上,研究了遥操作机器人的可靠性控制.通过使用Lyapunov稳定性方法和随机系统理论,得到了遥操作机器人的执行器概率分布依赖的渐近均方稳定的充分性条件,其中该条件是以线性矩阵不等式的形式给出,从而非常便于计算机转化为凸优化问题进行求解.最后用一个仿真算例来验证本文给出方法具有以下作用:首先,在考虑遥操作机器人的概率性执行器的故障的情况下,本文提出方法可以很容易地得到控制输入时延的上界;其次,在不考虑遥操作机器人执行器故障时,本文提出方法依然可以使用;最后,在考虑遥操作机器人的概率性执行器故障时,本文提出的方法都可以为其设计理想的控制器.

In this paper, the reliable controller design is considered for multi-degree of freedom-based tele-robotics. Time-delay estimation is employed to obtain the unknown dynamics and the external disturbances of robots online and to perform a compensation during the control. The faults of each actuator occur randomly and their failure rates are governed by a set of unrelated stochastic variables satisfying some certain probabilistic distribution. A new unified tele-robotics model is built by assuming the probabilistic distribution-based actuator fault and the input time varying delay. By considering the input time varying delay and the probabilistic actuator faults, we study the problem of the reliable control. By using Lyapunov functional method and stochastic systems theory, actuator distributed-dependent sufficient conditions for the exponentially mean square stability of tele- robotics system are obtained in the form of linear matrix inequalities, which can be solved easily by the application of convex optimization algorithms. A simulation example is given to show that： firstly, using the distribution information of the actuator, the maximum effective delay bound can be easily obtained for the tele-robotics system; secondly, the proposed design procedures can also be used when the tele-robotics is without actuator faults; lastly, the proposed reliable controller can stabilize the tele-robotics system with probabilistic actuator faults, which may be unstable under the designed controller without considering the faults of actuator.