15 Mobile Robot Navigation Control in Moving Obstacle Environment Using A^* Algorithm

The pace of development and automation urge the need of robots controlling much of the work which used to be done mainly by humans. The modern technology has emphasized on the need to move a robot in an environment which is dynamically changing. An example of such an application is the use of robots in industry to carry tools and other materials from one place to other. Since many robots would be working together, we need to ensure a collision free navigation plan for each of the robots. In this paper we find out the nearly most optimal path of the robot using A^* algorithm at each instant of time. The algorithm ensures that under any circumstance, there would not be any collision of the robot with any of the dynamically changing obstacles. The mobile robot navigation control has huge industrial application. It is used by the industry to send robots for surveys, data acquisition, doing specific work etc. The collision free movement of robot in a moving obstacle environment can be used to move robot in a world of robots. Hence it takes us closer to a fully robot control production∕service system, where robots do all the work without external help. The algorithm takes its input as a grid. This grid may be formed by scanning the surroundings. The positions of obstacles are known in this grid. We assume that the robot can make a limited number of moves, restricted to moving forward a unit step or turning (clockwise or anticlockwise) a unit direction. The A^* algorithm calculates the most efficient next move. When this algorithm was simulated, we saw the robot traveling without collision and reaching the destination. The path traced by the robot was very efficient and short even when robot was placed in a highly chaotic environment. Hence this algorithm can be used for efficient navigation control for robots.