Path Following and Velocity Optimizing for an Omnidirectional Mobile Robot

In this paper, the path following controller of an omnidirectional mobile robot (OMR) has been extended in such a way that the forward velocity has been optimized and the actuator velocity constraints have been taken into account. Both have been attained through the proposed model predictive control (MPC) framework. The forward velocity has been included into the objective function, while the actuator saturation has been considered as hard constraints. As shown in the simulation results, the OMR can converge to and follow a reference path successfully and safely. The forward velocity of the robot was close to the desired one and the desired orientation angle was achieved at a given point on the path, while the actuator constraints were not violated. Furthermore, to show the effectiveness of our proposed framework, a comparison with conventional approaches used to bound actuator constraints has been conducted. Mean squared error (MSE), integral squared error (ISE), and traveling distance were used as performance indices. As seen in the results, the proposed control strategy outperforms the conventional approaches. The proportion between translational and rotational velocities was optimized, although the limitation of the rotational and translational velocities was coupled via the OMR’s orientation angle.