轮式移动焊接机器人输出反馈线性化控制

Control of the Wheeled Mobile Welding Robot Based on Output Feedback Linearization

针对目前基于运动学模型的焊缝跟踪控制已经不能满足焊缝跟踪的高精度要求的问题,以一种后两轮差速驱动的5自由度轮式移动焊接机器人为对象,给出其动力学模型及其输出反馈线性化的过程,并提出一种基于此动力学的轮式移动焊接机器人路径跟踪控制方法。建立轮式移动机器人具有非完整力学系统形式的动力学模型,并推导出对应的状态反馈精确线性化模型。在此线性化模型基础上,考虑机器人动力学模型参数的不确定性,利用滑模变结构控制方法来设计动力学控制规律,选取线性切换函数和指数趋近律,设计滑模变结构控制器。并利用Lyapunov稳定性理论证明系统的稳定性且跟踪误差收敛,满足了移动机器人的轨迹跟踪要求,且具有设计方法简单、鲁棒性强的特点。通过仿真验证所提控制律的有效性和正确性。

As the requirement of high accuracy in trajectory tracking,the control result which based on the kinematics model can＇t meet the requirements,a five free degree wheeled mobile welding robot is concerned,which is differential driven by two behind wheels.The dynamics model and the output feedback linearization process are researched.A trajectory tracking control method for a wheeled mobile welding robot is also presented.The non-complete dynamic model for the four wheeled mobile welding robot is established.The exact feedback linearization model is proposed based on the nonlinear model.The control law is developed by variable structure control of sliding mode for ensuring the robot velocity asymptotically approaching to the desired velocity in uncertain system dynamics.A sliding mode controller is designed by selecting linear sliding surface and exponent reaching law.Used the Lyapunov stability theory to prove the stability of the robot and its tracking error convergence.The control law satisfies the trajectory tracking requirements for the wheeled mobile robot and has good robustness.Simulation results prove the effectiveness and correctness of the control law.