摘要
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 has characteristics such as time-varying, strong coupling and nonlinearity, and its dynamic model has large amount of calculation and is time-consuming. It is difficult to achieve effective real-time control. In this paper, for the dynamic control problem of a new 3-DOF parallel robot with redundant actuation, Lagrange method is used to get an accurate dynamic model. With this model, we design the dynamic sliding mode controller based on the exponential reaching law. At the same time, in order to weaken the chattering of the sliding mode control and improve the controller performance, arctangent function is introduced to improve the traditional sliding mode control based on the exponential reaching law. Finally, the dynamic model is analyzed through simulation and trajectory tracking is conducted in the presence of initial errors. The results show that the proposed model is correct. The running speed of the improved sliding mode controller is greatly improved. Besides, the tracking is fast with high precision. Its advantages lie in the minimal speed chattering and the stable output force. The system chattering is weakened effectively. It has better performance than the traditional sliding mode controller based on the exponential reaching law.
出处
《控制工程》
CSCD
北大核心
2015年第5期946-952,共7页
Control Engineering of China
基金
国家自然科学基金资助项目(51375210)
江苏高校优势学科建设工程资助项目(苏政办发〔2011〕6号)
镇江市工业科技支撑项目(GY2013062)
关键词
并联机器人
LAGRANGE
法
滑模控制
变参趋近率
反正切函数
Parallel robot
Lagrange method
Sliding mode control
Variable-parameter reaching law
Arctangent function
