基于观测器的全方位平台滑模轨迹跟踪控制

Trajectory Tracking Based on Observer and Sliding Mode Control for Omnidirectional Platform

以Mecanum轮型全方位移动平台为对象,建立运动学和动力学模型,研究机器人的观测目标优化控制问题。针对全方位轮特有的滑移和平台的重心偏移等不确定和非线性因素对运动的影响,采用多体动力学软件RecurDyn,构建了包含各种非线性因素的虚拟样机模型。提出采用等效控制的滑模控制器,通过非线性扩张状态观测器,可以实现对系统不确定项和干扰的估计,有效地降低了切换增益。引入双曲正切函数代替符号函数,消除了输出抖振。通过仿真分析,取得了良好的轨迹跟踪效果,表明该方法是有效和可行的。

In order to solve the problem of optimized control for observed object,a kind of robot called omnidirectional platform using Mecanum wheels was researched by kinematic and dynamic models in this paper.Uncertain and unlinear factors such as wheel＇s special slippgage and barycenter shift of the platform were considered,so that virtual prototyping including those factors was constructed by multi-body dynamic software RecurDyn.A sliding mode controller based on equivalent control was proposed.The uncertain part and disturbance can be estimated by nonlinear extended state observer（ESO）,which results in reduction of switch gain effectively.The symbols function was replaced by tanh function and the chattering phenomenon was eliminated.Simulations were carried out and the result is satisfied,which indicates that this method is effective and feasible.