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并联机构具有时变、强耦合、非线性特性,其动力学模型计算量大、耗时长,难以实现有效的实时控制。针对新型驱动冗余三自由度并联机器人的动力学控制问题,首先,采用Lagrange方法进行了完整精确的动力学建模,在此模型的基础上设计了基于指数趋近率的动力学滑模控制器,同时,为消弱滑模控制的抖振、提高控制器性能,引入反正切函数对传统指数趋近率滑模控制进行改进。最后对动力学模型进行仿真分析,并在存在初始误差的情况下进行轨迹跟踪。结果表明,所建模型正确,改进后的滑模控制器程序运行速度大大提高,跟踪快速、精度高,其突出优点是速度抖振极小、输出力输出平稳,能有效消弱系统抖振,较传统指数趋近率滑模控制器性能更好。
Parallel mechanism with time-varying, strong coupling, nonlinear characteristics, the kinematic model calculation of large, time-consuming and difficult to achieve effective real-time control. In order to solve the problem of dynamics control of a new type of redundant 3-DOF parallel robot, a complete and accurate dynamic modeling method based on Lagrange method is presented. Based on this model, a dynamic sliding mode control based on exponential approach rate is designed At the same time, in order to weaken the chattering of sliding mode control and improve the performance of the controller, the arctangent function is introduced to improve the traditional index approach rate sliding mode control. Finally, the dynamic model is simulated and trajectory tracking is carried out in the presence of initial errors. The results show that the proposed model is correct and the improved sliding mode controller greatly improves the running speed of the program and has the advantages of fast tracking and high accuracy. The outstanding advantages of the proposed sliding mode controller are that the speed of chattering is extremely small, the output force is stable, A better performance than the traditional index approach sliding mode controller.