Trajectory Control Using Fuzzy Logic Applied to a Parallel Robot

Abstract

This work presents the development of Mamdani-type fuzzy controllers for tracking linear trajectories in the workspace of a delta-type linear parallel robot. The system comprises three positioner actuators driven by direct current motors with incremental encoders for displacement reading. A multifunctional data module made the interface between the computer and the machine, capturing the signals coming from the encoders and supplying the control signals to the power circuits that drive the motors. Labview® software was used to implement the controller, using the fuzzy logic toolkit, and Matlab® to analyze and present the experimental results. There are three phases of control: velocity control, position control with trajectory tracking, and trajectory generation. In the analysis of the system's response curves and the obtained data, it was verified a very satisfactory performance of the controllers acting with 100 mm/s. The maximum steady-state error was -1.50mm for X-axis motion, -1.76mm for Y-axis motion, and 1.02mm for Z-axis motion, resulting in a trajectory tracking error of 1.26%.