A remark on passivity-based and discontinuous control of uncertain nonlinear systems

We address the problem of robust stabilisation of nonlinear systems affected by time-varying uniformly bounded (in time) affine perturbations. Our approach relies on the combination of sliding mode techniques and passivity-based control. Roughly speaking we show that under suitable conditions the sliding mode variable can be chosen as the passive output of the perturbed system. Then we show how to construct a controller which guarantees the global uniform convergence of the plant's outputs towards a time-varying desired reference, even in the presence of permanently exciting time-varying disturbances. We illustrate our result on the tracking control of the van der Pol oscillator

Exponential tracking control of a mobile car using a cascaded approach

In this paper we address the problem of designing simple global tracking controllers for a kinematic model of a mobile robot and a simple dynamic model of a mobile robot. For this we use a cascaded systems approach, resulting into linear controllers that yield global K-exponential stability of the closed loop system

Compositional modelling of distributed-parameter systems

The Hamiltonian formulation of distributed-parameter systems has been a challenging reserach area for quite some time. (A nice introduction, especially with respect to systems stemming from fluid dynamics, can be found in [26], where also a historical account is provided.) The identification of the underlying Hamiltonian structure of sets of p.d.e.s has been instrumental in proving all sorts of results on integrability, the existence of soliton solutions, stability, reduction, etc., and in unifying existing results, see e.g. [11], [24], [18], [17], [25], [14]

Null-space impedance control for physical human-robot interaction

In this paper two approaches for the correct task exe- cution during null-space impedance control of a kinematically re- dundant robot are presented. The algorithms guarantee safe and dependable reaction of the robot during deliberate or accidental interaction with the environment, thanks to null-space impedance control. Moreover, the correct execution of the task assigned to the end-effector is ensured by control laws relying on two different ob- servers. One is based on task space information and the other on the generalized momentum of the robot. The performance of the proposed control is verified through numerical simulations on 7R KUKA lightweight robot arm