速度受限/力矩饱和条件下基于观测器的移动机器人滑模控制

Observer Based Sliding Mode Control for Mobile Robots Under Speed Limited/Torque Saturation Conditions

  • 摘要: 针对轮式移动机器人速度受限/力矩饱和约束下的稳定控制问题,同时考虑建模误差和外界干扰等不确定性,提出了一种基于扰动观测器的自适应滑模控制方法. 建立四阶运动学模型,利用双曲正切函数的饱和特性设计运动学控制器,实现受限下的速度控制. 针对建模误差等模型不确定性,设计基于积分滑模控制器;考虑到力矩饱和非线性造成的输出受限,设计基于力矩差值的动态力矩调节器,同时设计基于误差信号的自适应扰动观测器,实现对外界扰动的实时估计. 构建Lyapunov函数保证系统的全局渐进稳定. 通过对比试验进一步验证了所提算法的有效性,且包含扰动观测器的控制算法具有更高的控制精度.

     

    Abstract: A disturbance observer-based adaptive sliding mode control method is proposed to address the stability control problem of wheeled mobile robots under speed constraints/torque saturation constraints, while considering uncertainties such as modeling errors and external disturbances.To achieve velocity control under constraints, we establish a fourth-order kinematic model, and design a kinematic controller via the saturation characteristics of hyperbolic tangent function. We design an integral sliding mode controller to address model uncertainties such as modeling errors. Considering the output limitation caused by torque saturation nonlinearity, a dynamic torque regulator based on torque difference is designed. An adaptive disturbance observer based on error signal is designed to achieve real-time estimation of external disturbances. Lyapunov functions is constructed to ensure the global asymptotic stability of the system. The effectiveness of the proposed algorithm is further verified through comparative experiments, and the control algorithm with disturbance observer has higher control accuracy.

     

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