Study On Motion Control Technique Of An Omni-directional Mobile Platform

With the progress of robotics, on different environment people have different requirements with mobile robots,the various machenical structures of mobile robot have been studied and built constantly. The well-known wheeled robot generally has two independent driving wheels, which can only move as arc movement or pivoting-turn on a certain terrain, but can’t complete integral process, including lateral movement, in order to move ineffectively in narrow area. To overcome this defect, people presented the an omni-directional locomotion method for the mobile robot. The omni-directional-wheeled mobile robot is a robotic system that can freely move on a plane at random time with three modes of movement. It is very suitable for working in more narrow and crowded spaces. This ability makes the omni-directional robot the special movement characteristics, and attracted the attention of many researchers, used in place of full of static or dynamic obstacles, such as robot soccer match, workshop, warehouse, hospital, etc. Mecanum wheel is an omni-directional mobile mechanism that has good performance and is widely used. It can successfully complete complex tasks like AGV, transportation and assembling mission in the fields that require precise positioning and high-precision navigation. This thesis includes the following aspects:Firstly, a lot of domestic and foreign papers were read, and the structure of the omni-directional-wheeled mobile robot was careful analyzed and studied including ultrasonic ranging and mobile devices etc. And a set of easy disassembling robot moving mechanism has been designed for narrow area;Secondly, the kinematics equation for a four-wheeled omni-directional mobile robot and the dynamic model for four-wheeled mobile mechanism combination are deduced with the Lagrange equation. The simulation model of the robot has been established for the control system building.Finally, based on the STM32, a high real-time control system has been built to achieve walking motor servo-control of the driving of detection of position and velocity, and to programm for sensor information acquisition and processing; In addition, the accuracy of the omni-directional prototype platform was proved by the experiments, and the route optimization and the control stability was tested.