This paper deals with the observability analysis and the observer synthesis of a class of nonlinear systems. The observer that we consider has a constant gain and concerns a class of uniformly observable systems. A sufficient condition permitting to design such a constant gain observer is given. The calculation of this gain is based on LMI technics.Copyright c © 2008 IFAC

Normal industrial PD control of robot has two drawbacks, it needs joint velocity sensors; it cannot guarantee zero steady state error. In this paper we make two modifications to overcome these problems. High-gain observer is applied to estimate the joint velocities, and a RBF neural network is used to compensate gravity and friction. We give a new proof for high-gain observer, which explains a ...

The main weakness of all control methodologies is the dependency of feedbacks to full state measurements. In practical situations, measuring the states of a given system may fail because sometimes the measurements are impossible and sometimes, possible, but too expensive. Observer design for highly nonlinear dynamics is an important issue, particularly when the locally observable dynamics are n...

For the purpose to estimate the state of nonlinear continuous-time systems, we focus on the increasing-gain observer regarded as generalization of the well-known high-gain observer. As compared with the previous results on increasing-gain observers, the assumptions under which the global asymptotic stability of the estimation error is proved are relaxed. The stability analysis is drawn by using...

Based on the techniques of high gain observer and adaptive estimation, an algorithm is proposed in this paper for sensor fault estimation in nonlinear systems. It is essentially assumed that a high gain observer exists for the fault-free system. A high gain adaptive observer is then designed for sensor fault estimation. The convergence of the algorithm is established under a persistent excitati...

A state observer is proposed for a class of multi-output nonlinear systems. The gain of this observer involves a design function that has to satisfy some mild conditions which are given. Different expressions of such a function are proposed. Of particular interest, it is shown that high gain observers and sliding mode like observers can be derived by considering particular expressions of the de...

Underactuated mechanical systems are systems with less actuators than degrees of freedom. Therefore, it is complicated to measure all states, i.e. angular positions or angular velocities, of the mechanical system. Alternative solution consists in an observer design such that unmeasurable states are estimated. For this purpose, a high gain observer for an Acrobot was introduced. By virtue of an ...

A hybrid static gain observer for systems described by a linear time-delay continuous part under impulsive feedback is suggested. The purpose of the observer is to asymptotically drive the state estimation error in the continuous states to zero and synchronize the sequence of modulated jump instants estimated by the observer with that of the plant. Conditions on the observer gain matrix to loca...