This paper deals with the tracking control problem of flexible joint robots under the assumption that the link and robot positions are the only measured signals. A globally asymptotically stable state feedback controller and a nonlinear observer is proposed which guarantees the semiglobal asymptotic tracking of the system obtained by the designed dynamic output feedback controller. Examples ill...

In this paper, we present a global state feedback tracking controller for underactuated surface marine vessels. This controller is based on saturated control inputs and, under an assumption on the reference trajectory, the closed-loop system is globally asymptotically stable (GAS). It has been designed using a 3 Degree of Freedom benchmark vessel model used in marine engineering. The main featu...

This paper discusses the design of a repetitive feedback controller for a grid-connected two-level three-phase voltagesource inverter connected between a DC source and the grid through an LCL filter. The controller incorporates a classical two loop feedback of the output current and the capacitor current in addition to a repetitive feedback loop. The results show that the proposed technique imp...

The static output feedback problem is one of the most important open questions in control engineering, [13]. Several solutions to this problem are available. The necessary and sufficient conditions for static output feedback stabilizability of linear continuous or discrete-time systems are given in [6] and [10] with iterative procedure to output feedback controller design. An approach based on ...

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...

A discrete time fault tolerant control system (DTFTCS) model in noisy environments driven by a delayed state feedback controller is developed. Delay-independent results are obtained using Lyapunov function approach and formulated as feasibility solution for a set of linear matrix inequalities (LMIs). In particular, second moment stability for the proposed feedback-delayed DTFTCS is considered. ...

This note considers the problem of stabilization by output feedback for a class of nonlinear Differential-Algebraic-Equation systems. The output feedback controller is constructed which ensures the closed-loop systems asymptotically stable. Not based on separation-principle that is commonly adopted in the literature, the output feedback controller design is coupled with that of the non-initiali...

For non-minimum phase plants, integral controller design based on disturbance cancellation is discussed. A new partial loop transfer recovery (LTR) technique is proposed. The target of the output feedback design is a minimum phase state feedback controller including a disturbance estimator. It is shown that the feedback property of the target can be recovered by a formal procedure using a Ricca...

The discrete-time robust repetitive control (RC, or repetitive controller, also designated RC) problem for nonlinear systems is both challenging and practical. This paper proposes a discrete-time output-feedback RC design for a class of systems subject to measurable nonlinearities to track reference robustly with respect to the period variation. The design relies on additive state decomposition...