Design On Omni-directional Robotic Mobile Platform With Mecanum Wheels

Currently,mobile robot is one of research focus that has been more widely adopted in the automation field and other areas like the military,aerospace,industrial production.This thesis studies on the design of mobile platform for mobile robot,to design an omnidirectional mobile platform that can be utilized in laboratory environment and has the ability to be equipped with robot arm module.Generally,the ordinary four wheel mobile platform has only two turning wheels to complete the movement,which makes them can only realize two degrees-of-freedom movement.However,the robot may face various forms of environment in practical applications,and two DOF movement obviously can not meet the requirements.For this reason,this thesis uses a new type of omni-directional wheels to achieve three degrees of freedom movement,and any complex motion on two dimensional plane can be realized by three DOF movement.This kind of platform will be able to expand the working radius of robots,so that it can be applied to a variety of narrow space.This thesis chooses Mecanum wheel mobile platform as final scheme through considering advantages and disadvantages of wheeled,crawler and multi-joint mobile platform.And we creatively added hydraulic-spring damping suspension system to the platform for reducing the mechanical vibration.Then,structure of Mecanum wheel was analyzed in this thesis for finding control arithmetic of inverse kinematics,which is a solution about how to control the movement of platform by controlling the rotation of four DC brushless motors.In order to realize the intended function,control system was designed in this paper,and we use Cortex-M4STM32F407 as a main control chip in module and circuit design.Motion controller is also applied for decreasing memory footprints of main controller.We use fuzzy logic control PID algorithm to avoid instability that caused by wheel-slippage and load-disturbance.Eventually,the simulation and experiments on this mobile platform prove that this algorithm is reliable and available to complete precise motion control of the whole platform.