Affiliation:
1. Robotics, Automatic Control and Cyber-Physical Systems Laboratory, Department of Digital Industry Technologies, School of Science, National & Kapodistrian University of Athens, Euripus Campus, 34400 Euboea, Greece
Abstract
Differential drive mobile robots, being widely used in several industrial and domestic applications, are increasingly demanding when concerning precision and satisfactory maneuverability. In the present paper, the problem of independently controlling the velocity and orientation angle of a differential drive mobile robot is investigated by developing an appropriate two stage nonlinear controller embedded on board and also by using the measurements of the speed and accelerator of the two wheels, as well as taking remote measurements of the orientation angle and its rate. The model of the system is presented in a nonlinear state space form that includes unknown additive terms arising from external disturbances and actuator faults. Based on the nonlinear model of the system, the respective I/O relation is derived, and a two-stage nonlinear measurable output feedback controller, analyzed into an internal and an external controller, is designed. The internal controller aims to produce a decoupled inner closed-loop system of linear form, regulating the linear velocity and angular velocity of the mobile robot independently. The internal controller is of the nonlinear PD type and uses real time measurements of the angular velocities of the active wheels of the vehicle, as well as the respective accelerations. The external controller aims toward the regulation of the orientation angle of the vehicle. It is of a linear, delayed PD feedback form, offering feedback from the remote measurements of the orientation angle and angular velocity of the vehicle, which are transmitted to the controller through a wireless network. Analytic formulae are derived for the parameters of the external controller to ensure the stability of the closed-loop system, even in the presence of the wireless transmission delays, as well as asymptotic command following for the orientation angle. To compensate for measurement noise, external disturbances, and actuator faults, a metaheuristic algorithm is proposed to evaluate the remaining free controller parameters. The performance of the proposed control scheme is evaluated through a series of computational experiments, demonstrating satisfactory behavior.
Subject
Artificial Intelligence,Control and Optimization,Mechanical Engineering
Reference57 articles.
1. Cobos Torres, E.O., Konduri, S., and Pagilla, P.R. (2014, January 4–6). Study of wheel slip and traction forces in differential drive robots and slip avoidance control strategy. Proceedings of the 2014 American Control Conference (ACC), Portland, OR, USA.
2. Cobos Torres, E.O. (2013). Traction Modeling and Control of a Differential Drive Mobile Robot to Avoid Wheel Slip. [Master’s Thesis, Oklahoma State University].
3. Dynamic Modelling of Differential-Drive Mobile Robots using Lagrange and Newton-Euler Methodologies: A Unified Framework;Dhaouadi;Adv. Robot. Autom.,2013
4. Anvari, I. (2013). Non-holonomic Differential Drive Mobile Robot Control & Design: Critical Dynamics and Coupling Constraints. [Master’s Thesis, Arizona State University].
5. Kouvakas, N.D., Koumboulis, F.N., and Sigalas, J. (2022, January 6–9). Manoeuvring of Differential Drive Mobile Robots on Horizontal Plane through I/O Decoupling. Proceedings of the 2022 IEEE 27th International Conference on Emerging Technologies and Factory Automation (ETFA), Stuttgart, Germany.