Obstacle-crossing strategy and formation parameters optimization of a multi-tracked-mobile-robot system with a parallel manipulator

Abstract

Multiple robots collaborative transportation is a new trend of robotic research in unmanned logistics area. Existing researches focus on the collaborative transportation on the flat ground, but usually neglect the obstacle-crossing problems in real-world environments. This paper designs a novel multi-robotsystem composed of tracked mobile robots used for collaborative transportation and investigatesits stairs climbing process. The robots are combined with each other by a parallel manipulator which is implemented to carry payloads. Meanwhile, actuated by the robots, the manipulator could achieve a 6 degrees of freedom configuration. A cable-driven unit is designed to provide extratension among these robots to improve the climbing capability. The statics model of the stair climbing process of a monorobot is analyzed. The climbing orientation of the robot is optimized and the stair climbing capabilityis improved by changing the climbing yaw angle. Based on the optimized mono robotclimbing process, the stair climbing formations of the multi-robot system are analyzed and the formationparameters are optimized with the maximal support angle.The climbing strategy is proposed according to the mass of payload and the height of the stair. The effectiveness of the climbing strategy is validated by the stair climbing experiments.