Null SpaceBased Formation Control with Leader Change Possibility This work discusses the implementation and experimentation of a control system designed to guide a multirobot formation of one aerial and three ground robots, in a trajectory tracking task. The implementation considers three partial formations of two robots, each one associated to a virtual structure, a straight line in the 3D space with its own formation controller. Two of the partial line formations are homogeneous formations of two ground vehicles, and the third one is a heterogeneous formation, involving a ground and an aerial vehicles. All the partial formations have the same reference for position, which is one of the ground vehicles. This also allows to discuss what would happen if this ground vehicle, the reference for all the line formations, and thus for the whole formation, presents a failure, what is considered here, in connection to an escorting mission. The result is that the designed control system is effectively able to accomplish the mission, even upon a failure of the reference robot, what is validated by experimental results also discussed here.

Nonlinear control of a group of tracked robots The paper presents a solution of the problem of nonlinear control law design for a group of mobile robots. The paper also provides a survey of modern methods and approaches to group control, discusses the use of methods for optimizing collective behavior, artificial potential fields, heuristic methods based on the recognition of the situation and the development of appropriate actions and methods based on the use of fuzzy logic. It is shown that when applying these methods, the problem of analyzing the stability of the obtained closedloop control system is complex. From the survey of modern methods, the basic conditions imposed on the synthesized law of group control of robots are highlighted. These conditions are adaptability to the external environment and asymptotically stable movement of mobile robots to a given point in space with a given type of order. Therefore, the paper presents a method which is based on new nonlinear approaches to the control of mobile robotsxe2x80x99 group, in particular, synergetic control theory. The main aspects of the proposed method are providing a stable moving of a group of tracked robots to the desire position, therefor in the result it makes a specified formation.