Motion Control Research Of A Three-wheeled Omnidirectional Mobile Robot

With the development of "Made in China 2025" in our country.Robots are playing an important role in our daily life.Mobile robot is one of the most important branches in robot family.According to the mobile properties,it can be divided as holonomic and nonholonomic ones and Omnidirectional mobile robot is one of the holonomic wheeled mobile robots.Compared to most of the car-like Robots,Omnidirectional mobile robot provide superior maneuvering capability.For getting rid of the restrict of the turning radius,it is able to turn in confine space and move in any direction,especially in places that need accurate positioning and heading direction.So more and more researchers are devoting themselves to the researching of the omnidirectional mobile robot.A three wheeled omnidirectional mobile robot is chosen as the research goal in this paper,which is steered by three separate motor.The kinematic and dynamic models of it are presented.Based on these models,the maximum velocity and acceleration that the robot can achieve when it moves in different directions are discussed and verified.For the special structure of the rolls around the omnidirectional wheel,sliding dynamic model of these rolls are revealed and the velocity error caused by it is discussed.The velocity error will,finally,leads to the trajectory error of the robot when it moves from the initial point to the terminal point.In order to eliminate the velocity error,virtue prototype of the mobile robot is established and analysed in ADAMS.Based on the PID velocity control algorithm in MATLAB/simulink,a co-simulation strategy is created by ADAMS&MATLAB.TMS320F2812 chip is used to build the motion control system.The hardware of it is designed.Meanwhile,the software is programmed in CCS6.0.Two different experiment are carried out on the robot platform and the results are compared.The experiment results indicate that the design model of the three wheeled mobile robot is correct and the strategy of co-simulation can make the velocity of the robot follow the reference velocity in real time.the motion trajectory error of the robot is decreased and its moving efficiency is improved at the same time.Based on the summary of this thesis,the future research work is envisioned.