Synthetic-analytic behavior-based control framework: Constraining velocity in tracking for nonholonomic wheeled mobile robots

This work presents a genetic programming control design methodology that extends the traditional behavior-based control strategy towards a synthetic-analytic perspective. The proposed approach considers the internal and external dynamics of the system, providing solutions to a general structure, and including analytic functions, which can be studied within the Control Theory framework. The method is illustrated for the tracking control problem under bounded velocity restrictions of a nonholonomic wheeled mobile robot. A classic Control Theory (CT) based controller that solves the tracking problem (but not the velocity constraint requirement) is chosen from the literature; based on its stability properties, a modified structure where the search of suitable analytic basis behaviors, fulfilling both control objectives simultaneously, can be introduced. The proposed framework takes the form of a learning process based on Genetic Programming (GP) which generates a set of nonlinear tracking controllers satisfying pre-specified velocity bounds. A collection of 9113 suitable nonlinear solutions were obtained to augment the ground controller. Simulations and real-time experiments are performed to illustrate the effectiveness of the methodology through the testing of the models with the best performance, as well as those with lower structural complexity. (C) 2019 Published by Elsevier Inc.