Abstract
A cooperative control method for multiple robots of single object transportation is proposed, which is applicable to unknown environment. In this method, all robots are controlled by the same algorithm, and they can have different objective tasks simultaneously. A task is expressed as the desired position of the object and the associated weight matrix, and each robot can set its own desired position and weight matrix independently of the other robots' tasks. By the proposed method, the robots can cooperatively transport the object to the composite desired position which is the weighted mid point of the desired positions set by all robots, without communicating their tasks with one another. The forces between the robots and the object are controlled as equally as possible during transportation. Furthermore, the internal forces can be suppressed only if some robots in danger of applying large forces broadcast on/off signal to the other robots. Accordingly, this method requires little amount of real-time communication among the robots and does not depend on the number of robots. Owing to these features, the method can deal with the situation where one robot has “path tracking task” and another robot which detects an obstacle has “obstacle avoidance task”; that allows cooperative object transportation with obstacle avoidance in unknown environment. The effectiveness and usefulness of the method are ascertained by computer simulation and experiment.
