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—We describe a framework for cooperative control of a group of nonholonomic mobile robots that allows us to build complex systems from simple controllers and estimators. The resultant modular approach is attractive because of the potential for reusability. Our approach to composition also guarantees stability and convergence in a wide range of tasks. There(More)
—This paper addresses the control of a team of nonholonomic mobile robots navigating in a terrain with obstacles while maintaining a desired formation and changing formations when required, using graph theory. We model the team as a triple, (), consisting of a group element that describes the gross position of the lead robot, a set of shape variables that(More)
In this paper we investigate feedback laws used to control multiple robots moving together in a formation. We propose a method for controlling formations that uses only local sensor-based information, in a leader-follower motion. We use methods of feedback linearization to exponentially stabilize the relative distance and orientation of the follower, and(More)
This paper uses geometric methods to study basic problems in the mechanics and control of locomotion. We consider in detail the case of \undulatory locomotion," in which net motion is generated by coupling internal shape changes with external nonholonomic constraints. Such locomotion problems have a natural geometric interpretation as a connection on a(More)
We present control methods for an autonomous four-rotor helicopter, called a quadrotor, using visual feedback as the primary sensor. The vision system uses a ground camera to estimate the pose (position and orientation) of the helicopter. Two methods of control are studied one using a series of mode-based, feedback linearizing controllers, and the other(More)
— We describe a method of generating and utilizing visual landmarks that is well suited for SLAM applications. The landmarks created are highly distinctive and reliably detected, virtually eliminating the data association problem present in other landmark schemes. Upon subsequent detections of a landmark, a 3-D pose can be estimated. The scheme requires a(More)
Analysis and simulations are performed for a simpliied model of a commercially available variant of the skateboard, known as the Snakeboard 1. Although the model exhibits basic gait patterns seen in a large number of locomotion problems, the analysis tools currently available do not apply to this problem. The diiculty lies primarily in the way in which the(More)