Exploration and map-building by cooperating robots

• Main Author: Khawaldah, Mohammad Mansour Deeb Al
• Published: University of Hertfordshire 2010
• Subjects: 629.82
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.606827

Exploration and map-building of an unknown environment is one of the main issues in mobile robotics due to its wide range of practical applications. Among them: search and rescue, hazardous material handling, military actions, planetary exploration, path-planning, and devastated area exploration. The purpose of this research work is to investigate the field of exploration and map-building with cooperating mobile robots. New and efficient exploration and mapping techniques are proposed by employing simple robot sensors. The research work also aims to integrate existing techniques and newly proposed ones to increase the exploration efficiency (i.e. to reduce the environment exploration time and the energy consumed by the robots to accomplish the exploration task). The goal of the proposed method is to have two cooperating mobile robots exploring a given unknown environment as fast as they can, while coordinating their actions and sharing their local maps in a continuous way to save time and robot motor energy. The new suggested exploration algorithms combine methods of line-of-sight, frontier-based, and wall-following exploration. Frontier-based and wall-following are important to guide the robots during the exploration. Wall-following is more relevant at the beginning of the exploration. Line-of-sight is an important way to detect free spaces. Combining these three methods represents an innovative exploration method that is not available in the current literature. Furthermore, it is proposed to use line-of-sight to generate grid-based maps. A new factor was introduced to enhance the performance of the frontier-based exploration. A general algorithm to optimize the exploration process is also proposed. The new algorithms were assessed through extensive testing. Test trials considered environments with different shapes, sizes and number of obstacles. The experimentation included a comparison with exploration algorithms available in the literature. The experimentation also included real robots implementing the proposed exploration and map-building algorithms which combine line-of-sight and wall following exploration techniques to generate grid-based maps. The results of the real experimentation confirmed the benefits of the proposed technique and led to promising results.