Simultaneous convergence of position and orientation of wheeled mobile robots using trajectory planning and robust controllers

Abstract

This article is devoted to the design of robust position-tracking controllers for a perturbed wheeled mobile robot. We address the final objective of pose-regulation in a predefined time, which means that the robot position and orientation must reach desired final values simultaneously in a user-defined time. To do so, we propose the robust tracking of adequate trajectories for position coordinates, enforcing that the robot’s heading evolves tangent to the position trajectory and consequently the robot reaches a desired orientation. The robust tracking is achieved by a proportional–integral action or by a super-twisting sliding mode control. The main contribution of this article is a kinematic control approach for pose-regulation of wheeled mobile robots in which the orientation angle is not directly controlled in the closed-loop, which simplifies the structure of the control system with respect to existing approaches. An offline trajectory planning method based on parabolic and cubic curves is proposed and integrated with robust controllers to achieve good accuracy in the final values of position and orientation. The novelty in the trajectory planning is the generation of a set of candidate trajectories and the selection of one of them that favors the correction of the robot’s final orientation. Realistic simulations and experiments using a real robot show the good performance of the proposed scheme even in the presence of strong disturbances.

Robust contour tracking of nonholonomic mobile robots via adaptive velocity field motion planning scheme

“…Consider a mobile robot equipped with two parallel steering wheels, whose forward differential kinematic model is described in previous studies [15][16][17] (see also Figure 1). …”

“…In addition, following the work of Becerra et al, 15 consider a reference in the vehicle body given by In addition, following the work of Becerra et al, 15 consider a reference in the vehicle body given by…”

“…The kinematic parameters r 1 , r 2 , and L are in general uncertain due to inherent issues in measurement and variations in the terrain and traction model, as well as to the unavoidable flexibility of the mechanical structure of the robotic vehicle. In addition, following the work of Becerra et al, 15 consider a reference in the vehicle body given by…”

Steering-angle computation for the multibody modelling of differential-driving mobile robots with a caster

“…Due to their simple and reliable propulsion mechanism, DDMRs are adopted in almost all research fields: pathtracking, [5][6][7][8][9] trajectory-planning, [10][11][12][13][14] position-estimation, 15,16 navigation control [17][18][19] and multi-robot control. [20][21][22] Robot models are the indispensable basis for the various applications mentioned earlier.…”

“…[20][21][22] Robot models are the indispensable basis for the various applications mentioned earlier. Generally speaking, kinematics models are more popular in applications, not only for estimation 15,16 and planning, 11,13,14 but also for control. 8,17,18,20 Most kinematics models involve differential equations due to the nonholonomic constraints of DDMRs, 7,14,15,19,22 while some kinematics models are based on geometric relations that rely on the instantaneous centre of curvature or trajectory approximation at each sampling instant.…”