Path following of a piezo-driven miniature robot based on fuzzy logic

This paper studied the path following case of a PZT-driven electromagnetic miniature robot which is used as a locomotion platform in a “Desktop Micro Robots Factory”. Considering the nonlinearity of the locomotive characteristics according to the difference equation describing the position and orientation changes of the robot, a fuzzy logic controller was designed to calculate the driven voltage amplitude applied to the two piezoelectric elements to fulfill the task. To overcome the overshoot when the robot joined the path from a far starting position, an improved method, which introduced a simple coarse initial pose error adjustment before the fuzzy controller took action, was proposed, resulting in a tracking error reduction preferably.