Notion of Control-Law Module and Modular Framework of Cooperative Transportation Using Multiple Nonholonomic Robotic Agents With Physical Rigid-Formation-Motion Constraints.

Consider cooperative manipulation and transportation of a rigid body by multiple two-wheeled nonholonomic robotic agents that attached to it, the agents are then physically constrained to maintain rigid-formation-motion (RFM); thus the system has two physical motion-constraints at two levels: 1) the nonholonomic constraint at the individual level and 2) the RFM constraint at the system level. First, we provide a novel notion: the encapsulation of a category of control with certain constraints for one motion-mode as a control-law module (CLM), any concrete control law with such constraints is called an instance of the CLM; here two CLMs are provided as the examples. Then we provide an RFM control framework by decomposing a feasible RFM configuration-path as a concatenation of partitions, with one type of CLMs for each partition; thus any instance for each partition can be designed separately and incorporated easily with the interchangeable property, which makes the framework modular, flexible, and adaptive, to satisfy different kinematics requirements. As a result, the transportation is achieved by RFM control of agents. Also, the RFM framework implies a valuable rigid-closure-method for accurate rigid body manipulation even when agents are not attached to the body.