In this paper we describe an experimental apparatus developed in our laboratory for research and advanced teaching purposes. The device consists in an untethered spherical vehicle that autonomously rolls on the laboratory floor, and can reach arbitrary positions and orientations in the environment. The kinematics of the vehicle are nonholonomic, and result from the combination of the kinematics...

This paper investigates the problem of global stabilization by state-feedback for a class of high-order nonholonomic systems in power chained form with time-varying delays. By using input-state-scaling, and adding a power integrator techniques, and choosing an appropriate Lyapunov-Krasoviskii functional, a state-feedback controller is constructed. Based on switching strategy to eliminate the ph...

Robust hybrid controller design is presented in this paper for motion/force control of mechanical systems subjected to a set of holonomic or classical nonholonomic constraints and in the presence of uncertainties about plant parameters. A uni ed and systematic procedure is employed to derive the controllers for both holonomic and nonholonomic constrained mechanical systems, respectively. The pr...

The paper deals with the robust energy-based stabilization of a wheeled inverted pendulum, which is an underactuated, unstable mechanical system subject to nonholonomic constraints. The equilibrium to be stabilized is characterized by the length of the driven path, the orientation, and the pitch angle. We use the method of Controlled Lagrangians which is applied in a systematic way, and is very...

Formation control is an important problem in multi-agent systems. In this paper, it is assumed that a target is moving with a disturbed dynamics, and then, a k-coverage formation control is designed for every nonholonomic agent to improve tracking qualities. A virtual agent approach is adopted in the formation control design. The stability of the tracking error system is analyzed. Finally, some...

The paper presents the first result on ISS properties of dynamic unicycle models describing nonholonomic mobile robots. It is known that ISS is related to smooth stabilizability, however this relation cannot exclude the possibility of non smoothly stabilizable systems to possess ISS properties. In fact, it is shown that in a certain topology that seems to suit the nonholonomic nature of the mob...

This note describes a logic-based hybrid controller for the well-studied nonholonomic integrator. Our controller provides Lyapunov stability and is designed so that the control signals remain uniformly bounded and have at most a nite number of discontinuities in any nite interval. In particular, no \chattering" occurs. Two alternative controllers, which use only partial state information, are a...