Combined Path-following and Obstacle Avoidance Control of a Wheeled Robot

Abstract

This paper proposes an algorithm that drives a unicycle type robot to a desired path, including obstacle avoidance capabilities. The path-following control design relies on Lyapunov theory, backstepping techniques and deals explicitly with vehicle dynamics. Furthermore, it overcomes the initial condition constraints present in a number of path-following control strategies described in the literature. This is done by controlling explicitly the rate of progression of a “virtual target” to be tracked along the path; thus bypassing the problems that arise when the position of the path target point is simply defined as the closest point on the path. The obstacle avoidance part uses the Deformable Virtual Zone (DVZ) principle. This principle defines a safety zone around the vehicle in which the presence of an obstacle induces an “intrusion of information” that drives the vehicle reaction. The overall algorithm is combined with a guidance solution that embeds the path-following requirements in a desired intrusion information function, which steers the vehicle to the desired path while the DVZ ensures minimal contact with the obstacle, implicitly bypassing it. Simulation and experimental results illustrate the performance of the control system proposed.

A reactive collision avoidance algorithm for nonholonomic vehicles

“…Lemma 2: Consider the vehicle described by (1), and an obstacle modeled by (3). If Assumptions 1 and 3-5 hold, then, for ψ (j) dca (t) given by (17),ψ (j) dca (t) is bounded by…”

Receding Horizon Model-Predictive Control for Mobile Robot Navigation of Intricate Paths

“…[9] presents a reactive path following controller for a unicycle type mobile robot built with a Deformable Virtual Zone to navigate paths without the need for global path replanning.…”

Path Following with an Optimal Forward Velocity for a Mobile Robot

“…For example, in (Bak et al, 2001), the forward velocity decreases as the robot rotates around a sharp corner by scaling the forward velocity. In (Lapierre et al, 2007), the forward velocity is controlled when an obstacle is detected. In this paper, the velocity profile is shaped to comply with environmental constraints and robot dynamics along some lookahead distance corresponding to the N -step prediction horizon of the MPC framework.…”

“…To avoid the obstacle, a sensory system should detect the obstacle, measure its distance and orientation for replanning the robot's path. In (Lapierre et al, 2007), an obstacle avoidance algorithm based on the use of a continuous Deformable Virtual Zone (DVZ) is combined with a path following controller. In (Maček et al, 2009), global path planning, path following, and a collision avoidance scheme are integrated in a unified framework, namely the Traversability-anchored Dynamic Path Following (TADPF).…”