一种柔性机械臂末端轨迹跟踪的预测控制算法

针对柔性机械臂末端轨迹跟踪的内动态不稳定和模型不精确问题,提出一种用于柔性臂末端轨迹跟踪的预测控制算法.利用输入-输出线性化的方法使得柔性臂末端变量和弹性变量解耦,并根据状态反馈设计出一个非线性预测控制系统,将轨迹跟踪问题转换为状态跟踪问题.该控制系统通过平衡末端跟踪误差、弹性变量和控制力矩3个最优指标来克服内动态不稳定性,并采用最优控制律求解和力矩求解相分离的策略来提高运算速度,同时引入了实际输出数据进行误差补偿以减少模型误差对末端轨迹跟踪精度的影响.仿真结果表明,所提出的预测控制算法在保证柔性臂内动态稳定的同时,能有效解决模型失配引起的控制精度下降问题,并具有较快的运算速度.

Real time predictive control algorithm for endpoint trajectory tracking of flexible manipulator

A novel predictive control algorithm was proposed to solve the problems of internal dynamics instability and model inaccuracy encountered in endpoint trajectory tracking of flexible manipulators. The end variables of a flexible manipulator were decoupled from its elastic variables using the technique of input-output linearization, based on which a nonlinear predictive control system was designed through state feedback to transform the trajectory tracking problem to a state tracking problem. A trade-off among the endpoint tracking error, the elastic variables and the control input were made in the control system to avoid the unstable internal dynamics. The optimal control law and the torques to drive the joints of the flexible manipulator were separately computed to improve computation speed. The actual output data were introduced for tracking error compensation in order to reduce the effects of model deviation on the endpoint tracking accuracy. Simulation results show that the predictive control algorithm can effectively overcome the internal dynamics instability and solve the problem of control performance deterioration made by model-mismatch with desirable real-time computation speed.