Employing disturbance observers is an effective way of enhancing the stability and performance of the control systems subject to disturbances. Disturbance observers have been extensively used for control of mechatronic systems since their introduction in the 1980s. This thesis studies the design of nonlinear disturbance observers for robotic manipulators and their applications in the control of...

We consider the almost disturbance decoupling problem (ADDP) and/or almost D-bounded disturbance decoupling problem ((ADDP) D) with internal stability for linear systems subject to input saturation and input-additive disturbance via linear static state feedback. We show that the almost D-bounded disturbance decoupling problem with local asymptotic stability ((ADDP/LAS) D) is always solvable via...

This paper presents an attitude control strategy and a newnonlinear tracking controller for a spacecraft carrying a large object, such as an asteroid or a boulder. If the captured object is larger or comparable in size to the spacecraft and has significant modeling uncertainties, conventional nonlinear control laws that use exact feedforward cancellation are not suitable because they exhibit a ...

This paper proposes a control parametrization under Model Predictive Controller (MPC) framework for constrained linear discrete time systems with bounded additive disturbances. The proposed approach has the same feasible domain as that obtained from parametrization over the family of time-varying state feedback policies. In addition, the closed-loop system is stable in the sense that the state ...

Categorizes three direct-axis and four quadrature-axis models, along with the basic transient reactance model. Discusses some of the assumptions made in using various models and presents the fundamental equations and concepts involved in generator/system interfacing. Covers, generally, the various attributes of power system stability, recognizing two basic approaches. The first is categorized u...

Analysis of advanced displacement in construction progress of tunnel excavation with weak surrounding rock is carried out by numerical method and comparison of model test result. In allusion to the problems of regional landslides and extruded large-deformation seriously impacting the stability of rock mass in construction process of large-section tunnel with weak surrounding rock, the elastic-p...

Disturbance observer based robot control algorithms provide good control performance while giving a straightforward method of gain selection. Unfortunately, the stability of these algorithms has not been shown rigorously for nonlinear systems such as robots. This paper demonstrates that a disturbance observer based algorithm can be made equivalent to the well-known passivity-based approaches of...

The stability of spacecraft attitude is studied with considering sinusoidal disturbance. A passive attitude controller without angular velocity measurement for spacecraft described by quaternion is designed. The passive controller has no information related to system parameters. So it has robustness to model error and uncertainty of model parameters. The stability of spacecraft attitude control...

Abstract: In this paper, a decentralized control problem is considered for multimachine power systems with nonlinear interconnections and disturbances. A direct feedback linearization compensator is employed to cancel most of the nonlinearities, and then a backstepping procedure is applied to deal with the interconnections and to reduce the effects of a disturbance that does not satisfy the mat...

As well known, robot manipulator is utilized in many industrial fields. However manipulator motion has a single function at most and is so limited because of low degree-offreedom motion. To improve this issue, it is necessary for the robot manipulator to have redundant degree-of-freedom motion. The motion spaces of redundant manipulator are divided into work space motion and null space motion. ...