Trajectory Tracking Control Strategy Of Wheeled Mobile Robot

In recent years,Wheeled Mobile Robots(WMR)are widely used.As one of auto guide ground mobile robots,WMR attracts unprecedented attentions that numerous scholars bring up different points of view on the control mechanism on different aspects because of its unique advantages.Nevertheless,it is hard to design a controller based on a single model to meet the requirements,because the motion control of mobile robot faces variety of challenges such as environmental complexities,the strain of communication band,etc.Many researchers design the effective trajectory tracking controllers on either dynamic or kinematic.However,this thesis provides a new law of trajectory tracking control from the perspective of kinematics.This thesis further considers network control,dynamics,sideslip and sliding in the real world and then provides related control law to integrate the control systems and complete the trajectory tracking control.The specific contents are as follows:1.In allusion to the WMR system,this thesis builds up a dynamic mathematical model and designs a continuous feedback control mechanism based on back-stepping and Lyapunov method from perspective of kinematics combining with related theoretical knowledge of stability to demonstrate that the control law enables the uniformly stability for the system.Meanwhile,through the numerical simulation,this thesis also demonstrates that WMR can follow the established trajectory with the proposed control law.2.Considering the control of network with strain of communication band,it is to select representative event-triggered mechanism(ETM).Based on kinetic model of the mobile robot in ideal environment,this thesis respectively designs static and dynamic ETM.As the stability analytical result shows that it demonstrates that dynamic ETM has larger interexecution and static ETM indicates better control effect.3.Only generalized velocity control variables are computed on perspective of kinematics.Considering friction,rotational inertia and more factors in a real world environment,in order to achieve a better control effect,this thesis from perspective of kinematics introduces non-linear extended state observer to estimate disturbance;and designs self-adaptive sliding mode controller which improves the buffetings in traditional sliding mode control.The numerical simulation also proves that.By introducing non-linear extended state observer,which can greatly estimate disturbance and provide disturbance estimation with small error,the controller achieves a better control accuracy.4.Considering that wheels deform leading to sideslip and sliding due to gravity,turning of the mobile robot and other factors in a real world environment,in allusion to the trajectory tracking control under the situations of sideslip and sliding,this thesis respectively establishes dynamic mathematical models and designs the different trajectory tracking controllers for situations of sideslip and sideslip and sliding.The proof of stability demonstration and numerical simulation verify that the proposed control law can enable such mobile robot to complete trajectory tracking under the conditions of the mobile robot occurring sideslip and sliding.