基于模型不确定性自适应估计的工业机械臂改进TDE控制策略

Improved time-delay estimation-based control strategy of industrial robotic manipulators based on adaptive estimation of model uncertainty

在对工业机械臂进行控制时,采用传统的基于时延估计的控制(TDEC/TDC)方法难以有效平衡控制精度与输入抖振,针对这一问题,提出了一种基于模型不确定性自适应估计的改进TDEC策略。首先,结合多自由度机械臂动力学模型,构建了时延估计(TDE)控制器;然后,利用动力学模型扰动项的时延估计值及时延估计梯度值,提出了机械臂动力学模型不确定性自适应估计器,并将TDEC及滑模控制作为辅助控制策略,与所提出的自适应估计器相结合,形成了完整的工业机械臂改进TDEC方法;基于Lyapunov方法,对改进的TDEC控制策略进行了稳定性分析;最后,通过仿真分析和实验的方式,验证了改进的TDEC控制方法的优越性。研究结果表明:相较于传统的TDEC方法,改进的TDEC控制策略在机械臂加载/未加载条件下的控制精度平均分别提高了62.29%及45.38%;相较于已有的自适应TDEC方法,改进的TDEC控制策略在机械臂加载/未加载条件下的控制精度平均分别提高了23.31%及36.40%;同时,通过测量计算控制输入能耗的平方值积分,表明了改进的TDEC控制策略能够在保留TDEC优势的基础上有效抑制输入抖振,且能够有效地与已有自适应TDEC方法相结合,提升了对工业机械臂的控制效果,其具有良好的灵活性。

Aiming at the problem that the traditional time-delay estimation-based control(TDEC/TDC)method is difficult to effectively balance the control accuracy and the input chattering phenomenon when controlling industrial robot arms.An improved TDEC strategy based on adaptive estimation of model uncertainty was proposed.First,the time delay estimation(TDE)controller was constructed by combining the dynamic model of a multi-degree-of-freedom manipulator.Then,an adaptive estimator for the uncertainty of the manipulator dynamic model was proposed by using the TDE and the corresponding gradient value of the disturbance term.TDEC and sliding mode control was used as auxiliary control strategies and combined with the proposed adaptive estimator to form a complete improved TDEC framework for the manipulator.Further,the stability analysis of the improved TDEC control strategy was carried out based on Lyapunov method.Finally,the superiority of the improved TDEC control method was verified by simulation analysis and experiment.The results show that compared with the traditional TDEC method,the control accuracy of the improved TDEC control strategy can be improved by 62.29%and 45.38%respectively under the loading and unloading conditions.Comparing with the existing adaptive TDEC method,the control accuracy of the improved TDEC strategy can be improved by 23.31%and 36.40%respectively under the loading and unloading conditions.At the same time,by measuring and calculating the square value integral of the control input energy consumption,it is shown that the improved TDEC control method can effectively suppress the input chattering phenomenon on the basis of retaining the advantages of conventional TDEC,and can be effectively combined with the existing adaptive TDEC method for improving the control effect,showing its flexibility.