Saturated Proportional-integral-type Control of UWMRs with Experimental Evaluations

In this paper, a saturated proportional-integral (PI)-type controller for unicycle-type wheeled mobile robots (UWMRs) is designed. The advantages of the novel controller are the robustness to external disturbances and the ability to keep the control into admissible limits. The desired trajectory should satisfy the so-called virtual reference system and be bounded for all time. Lyapunov’s theory and Barbalat’s lemma are used to prove the convergence of the tracking errors. An analysis of when the system is affected by disturbances is also given. To assess the performance of the proposed controller, an experimental real-time comparison of five schemes, including the proposed one, is presented. All the tested controllers guarantee the motion control goal and can produce saturated control action. A circular reference trajectory for the tracking task is used to perform the comparison. The proposed PI-type controller presents the best trajectory tracking performance, while the generated control action remains bounded.