Simulatneous Path Following and Obstacle Avoidance Control of a Unicycle-type 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 technics and deals explicitly with vehicle dynamics. Furthermore, it overcomes initial condition constraint 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 is using the Deformable Virtual Zone principle, that 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, that steers the vehicle to the desired path while the DVZ is virtually keeping a minimal contact with the obstacle, implicitly bypassing it. Simulation and experimental results illustrate the performance of the control system proposed.

Autonomous wheelchair navigation with real time obstacle detection using 3D sensor

“…The system reaction is made in order to reform the risk zone to its nominal shape. The main characteristic of this approach is that there is no geometrical modelling of the obstacles, but rather a vector representation of the interaction between the robot and its environment [10]. On the other hand, experiments carried out on real robots with sensors have shown that there is never a real symmetry in the deformation of the DVZ and then it couldn't fall into local minima [11].…”

“…This problem can degrade the robot's performance and in some cases causes robot instability [16]. In other works, path following control set up the vehicle's forward velocity tracks a desired speed profile, while the controller acts on the vehicle orientation to drive it to the path [10,17]. These methods deal with the kinematic, dynamic and parameter uncertainty of the mobile robot.…”

Coordinated trajectory tracking and collision-avoidance in dynamic environment for robots with double-integrated nonlinear dynamics

“…Refer to [12] for more investigation about DVZ concept. In [13] authors propose an algorithm for path following which includes obstacle avoidance capabilities. The obstacle-avoidance part utilizes deformable virtual zone concept to define a safety zone around the robot.…”

A redundancy-based approach for visual navigation with collision avoidance

“…In [19], a laser range finder and monocular vision enable navigation in an office environment. Simultaneous obstacle avoidance and path following is presented in [20], where the geometry of the path (a curve on the ground) is perfectly known. The authors of [21] deform the desired trajectory to avoid sensed obstacles.…”