SIMPLIFIED CONTROLLER FOR A THREE WHEELED OMNI DIRECTIONAL MOBILE ROBOT

摘要

This paper presents the work on developing a controller for the three-wheeled omni-directional mobile robot for the operation on a flat terrain. The controller was designed using layered architecture. Using layered architecture, each layer (world frame, robot frame and motor frame) can be independently controlled without affecting others. The trajectory of the robot is specified as the time variation of the position coordinates and the orientation of the robot with respect to a fixed frame. The trajectory is dictated by the speeds of the three omni-directional wheels. Being a holonomic robot, the designed robot can achieve any continuous trajectory. The trajectory is planned on the fixed world frame. Then, it is transformed to the time-varying robot body frame. The velocities of the wheels are computed with respect to the body frame. A proportional integral derivative (PID) controller is utilized for the control of each parameter. Consequently, nine PID controllers are employed for trajectory control. The MATLAB~® SIMULINK~® platform is used to develop the kinetic model of the system. The designed robot has been implemented in hardware. This can be utilized as a low-cost simple and reliable robot platform to carry out testing with minimum requirements.