Compliance: encoded information and behavior in a team of cooperative object-handling robots

The role of compliant elements in a team of distributed object handling robots is discussed from the information, robot behavior, and cooperation protocol points of view. Also main benefits and some limitations on implementing compliant units in a group of distributed cooperative object handling robots are shown. It is proved that, any error in position of the stiff robots executing the Constrain-Move strategy [1] to transport an object will cause a movement lock in the system. Also, difficulties in stabilizing the robot-object contact in a team of distributed mobile object handling robots with stiff arms are discussed. It is verified that, specially designed compliant arms can be used to simplify the robotobject stabilization task and to remove the movement lock. Doing so, the system would be less sensor dependent and the robot control system is simplified. In addition, a distributed method is developed to help the compliant robots to solve the lock problem when there is a limitation on possible softness of the arms. Based on the discussions, a novel compliant arm is introduced and its main features are reviewed. Moreover, the role of this compliant mechanism in simplifying the distributed cooperation and coordination protocols, the robot information system, and the robot controller for executing the cooperative object transportation and object lifting tasks are given. Simulation results are provided to support the discussion.