Ghost-goal Algorithm for Reactive Safe Navigation in Outdoor Environments

A force field algorithm based on inclinometer readings is presented. It leads the robot to the goal by preventing it from turning upside down because of the inclination of the terrain. The method is supported by a navigation algorithm, which helps the system to overcome the well known local minima problem for force field-based algorithms. By appropriately selecting the "ghost-goal" position, known local minima problem can be solved effectively. When the robot finds itself in danger of local minimum, a "ghost-goal" appears while the true goal temporarily disappears in order to make the robot go outside dangerous configurations. When the robot escapes the possible dangerous configuration the system makes the true goal appear again and the robot is able to continue on its journey by heading towards it. Simulation results showed that the Ghost-Goal algorithm is very effective in environments with complex rugged terrain for a robot only equipped with an inclinometer.