一类具有多种不确定性机器人系统的自适应控制

机器人系统含有不同类型的不确定性因素,这些因素的存在可能会影响系统的控制精度,甚至引起系统不稳定。针对具有外部干扰、内部动力学参数不确定性以及未知死区特性的一类不确定性机器人系统,提出了一种基于干扰观测器的自适应控制器。首先建立具有外部干扰的机器人系统非线性数学模型,并对模型中内部动力学参数不确定性和未知死区特性进行了分析。采用非线性干扰观测器对系统所受到的外部干扰进行估计和补偿,在干扰观测器的基础上设计自适应控制器用来处理内部动力学参数的不确定性以及未知的死区特性。最后采用李雅谱诺夫函数法从理论上证明了系统的稳定性和位置跟踪误差的收敛性,并采用数值仿真验证了所设计方法的有效性。

Adaptive Control for a Class of Robotic Systems with Multiple Uncertainties

Robotic systems suffer from different types of uncertainties which may affect the system control accuracy and even cause the system unstable. In this paper, for a class of uncertain robotic systems with external disturbance, internal dynamic parametric uncertainty and unknown dead-zone, an adaptive controller based on disturbance observer is proposed. First, the nonlinear mathematical model of robotic systems subject to external disturbance is established and the internal dynamic parametric uncertainty and unknown dead-zone in the system are analyzed. Then nonlinear disturbance observer is employed to estimate and compensate for the external disturbance. Based on the disturbance observer, an adaptive controller is then designed to deal with the uncertain dynamic parameters and unknown dead-zone. Finally, the stability and the convergence of the position tracking error of the system are proved via Lyapunov function analysis. Digital simulations demonstrate the validity of the proposed approach.