Design And Implementation Of Omnidirectional All-wheel Drive Mobile Robot

With the further development of today's social intelligence level,the advantages of mobile robots are gradually emerging in various fields.As a kind of omnidirectional wheeled mobile robot,omnidirectional full drive mobile robot plays an important role in the field of mobile robots because of its more flexible motion characteristics.Aiming at omnidirectional full drive mobile robot system,the following main work has been carried out and completed:Firstly,the mechanical structure of omnidirectional full drive mobile robot is designed by SOLIDWORKS,and the virtual assembly of omnidirectional full drive mobile robot is completed.The finite element analysis software ANSYS Workbench is used to carry out static analysis of load bearing components to meet the requirements of strength and stiffness.Then the forward and inverse kinematics equations of omnidirectional full drive mobile robot are given,and the kinematics characteristics of the mobile robot under three modes of straight line motion,fixed-axis rotation motion and steering motion are analyzed concretely.Then,the dynamic characteristics of the mobile robot are analyzed,and the dynamic equation of the mobile robot is given.According to the kinematics simulation results,the optimal motion mode of the mobile robot under different curvatures of the trajectory is given.According to the dynamic simulation results,the parameters of the selection of the direct motor in the system are given.Secondly,according to the structural characteristics of four direct motors which need to be controlled simultaneously during the movement of omnidirectional full drive mobile robot,the method of multimotor cooperative control is applied in omnidirectional full drive mobile robot system to further improve the motion performance of mobile robots.Firstly,the mathematical model of brush DC motor is established.Aiming at the speed closed loop control system of single motor,a fuzzy PID controller is designed to make the single motor system have the advantages of small overshoot,fast response speed and strong anti-interference performance.Aiming at the multimotor cooperative control system,a deviation coupling controller based on fuzzy PI speed compensator is designed by using the deviation coupling control method of multimotor.When the direct motor is disturbed by different magnitudes,the synchronization error between the direct motors in the system is smaller.Then,aiming at the unique structure of omnidirectional full drive,the dead reckoning model of mobile robot in three cases of straight line motion,origin rotation motion andsteering motion is established.Then,an improved square root unscented Kalman filter fusion algorithm is proposed,which integrates trajectory estimation and laser location algorithm to eliminate the accumulative error of dead reckoning and solve local optimal solution caused by traditional laser matching positioning.The simulation results show that mobile robot can obtain more accurate position and attitude angle data.Finally,a three-storey frame structure of omnidirectional full drive mobile robot control system is designed,including the monitoring layer,the control layer and the execution layer.Then,the hardware design and the software design of the control system of each framework layer are carried out respectively.Finally,the experiment of multimotor coordinated control and system positioning is carried out,the validity of the designed control system is verified.