| Mobile robot technology has made great strides in recent years in China’s manufacturing,service,and medical industries.Mecanum wheeled mobile robots have become more and more widely used due to their unique wheels,which are easy to manipulate,efficient,and omnidirectional mobile.Due to the high pair contact be tween the roller of the Mecanum wheel and the ground,non-continuous contact inevitably causes vibration during movement.Therefore,the stress concentration and deformation of the roller have a significant impact on the stability of the robot’s motion,due to the existence of axial force on the roller and the influence of the ground,the wheel body may also slip,affecting the motion accuracy of the robot,In order to solve the above problems,this paper takes the Mecanum wheeled mobile robot as the resear ch object,and conducts research from two aspects: the structure and motion control of the Mecanum wheeled mobile robot.The specific research content is as follows:(1)Based on the structural and kinematic characteristics of the Mecanum wheel,a transient dynamic analysis of the Mecanum wheel was conducted to obtain the deformation and stress changes of the roller during movement.The results showed that when the roller alternately moved,contact fatigue and wear at the end of the roller were prone to occur,which was the main reason for the vibration of the Mecanum wheel and laid the foundation for the optimization method of the roller structure in the following article.(2)Based on Hertz contact theory,a contact model between Mecanum’s wheel roll and the ground is analyzed.Through the analysis of the forces acting on the roller when contacting the ground,contact simulation experiments are conducted.From the perspective of changing the outer layer material and end thickness of the roller,orthogonal experiments for roller optimization are designed based on the ANSYS Workbench platform to obtain the optimal roller optimization scheme.By comparing and analyzing the results before and after the optimization,It was found that the contact stiffness at different contact points along the roller axis after roller optimization has better uniformity,thereby verifying the correctness of roller optimization.(3)Kinematic analysis of a Mecanum four-wheel system was performed to derive the kinematic relationship between wheel speed and vehicle speed for a mobile robot equipped with Mecanum wheels.The Lagrange equation was used to analyze the dynamics of the robot,and a dynamic state space model was determined.Subsequently,ADAMS software was used to conduct kinematic simulation analysis of the Mecanum wheeled robot before and after roller optimization.The optimized simulation results showed that the vibration amplitude of the robot in the vertical direction decreased,The speed fluctuation is also more stable th an before optimization,which improves the motion stability of the robot and further validates the rationality of roller optimization.(4)Based on the analysis of errors in the simulation of robot motion,the effect of sliding factors on the motion accura cy of a mobile robot equipped with a mecanum wheel is considered,a kinematics equation for the slipping of the Mecanum wheeled mobile robot is established.Subsequently,a sliding model of the robot is built using MATLAB/Simulink modules.Finally,a PID c ontrol program is designed.When the robot moves longitudinally,a lateral interference signal is given to simulate the slipping phenomenon during movement.The simulation results show that,This control program can effectively and timely correct the posit ion deviation generated during the robot movement process,thereby improving the robot motion accuracy. |
