Path tracking control for a four wheel differentially steered vision robot

A robotic platform for spraying in fields was used to demonstrate control problem for autonomous vehicle in agriculture. The approach presented here is a simple and effective solution for the path tracking problem of a 4-Wheel Differentially Steered (4WDS) vision mobile robot using a fuzzy-PID controller. The proposed control strategy uses a simple method to avoid motion interference among the four wheels. The synthesis procedure is simple and allows the fuzzy controller and PID controller to switch freely according to a switch index. Control of the platform is provided through a platform computer (PC104 system). Experiment results demonstrate that this controller can ensure the robot to turn at small radius and adjust its speed as turning automatically.