Virtual Obstacle Parameter

Virtual Obstacle Parameter Optimization for Mobile Robot Path Planning: A Case Study

Hussein Hamdy Shehata# Josef Schlattmann

Robotics and Mechatronics Department Systems Technology and Design Methodology, AmP

Benha Faculty of Engineering, Benha University Hamburg University of Technology, TUHH

13512 Benha, Egypt 21073 Hamburg, Germany

[e-mail] [e-mail]

Abstract— Path planning algorithms play a vital role in the field of robotics. Amongst these, the potential field algorithm is widely used due to its simplicity, elegant mathematical model and computationally efficient. Although it serves the basic purpose of avoiding obstacles and movement towards the goal,

It is first proposed by Khatib [1] for manipulators and mobile robots. This method creates a repulsive potential field around the obstacles and an attractive potential field around the goal. As the robot travels, the repulsive forces from obstacles drive the robot away from them. The attractive force field pulls the robot towards the goal. Koren and Borenstein [2] described the Virtual Force Field (VFF) concept. A mathematical representation of the robot with the environment was derived and used to analyze the limitations of the potential field. The following limitations were identified: local minima resulting in cyclic behavior, no passage between closely spaced obstacles, oscillations in presence of obstacles and oscillations in narrow passages [2], [3]. Velagic et al. [4] combined the potential field method with an obstacle pruning method that used the concept of visibility field to solve the problem of Goals Not Reachable due to Obstacles Nearby (GNRON). An improved wall following behavior coupled with potential field was proposed by Zhu et al. [5]. Li et al. [6] also included the goal distance in the obstacle potential. However, the repulsive potential was modified to change exponentially with the distance from the obstacle. The exponential decrease of potential around the obstacle can however cause the paths to be very close to obstacle raising safety issues. Jia and Wang [7] represented obstacles as a set of linear segments along their boundary and defined the repulsive potential as a line integral along its contour. Calculating linear integral increases the computational cost during online path planning. Yin and Yin [8] modified the attractive potential by including the relative acceleration in the goal potential field. To tackle this situation, a virtual obstacle concept for obstacle avoidance was proposed