This study introduces a mixed 2 fuzzy output feedback control design method for nonlinear systems with guaranteed control performance. First, the Takagi and Sugeno fuzzy model is employed to approximate a nonlinear system. Next, based on the fuzzy model, a fuzzy observer-based mixed 2 controller is developed to achieve the suboptimal 2 control performance with a desired disturbance rejection co...

Various methods are presented to control the attitude of satellite due to lack of information of yaw axis attitude so far.&#10In this paper, a new method is used which is more general and is applicable to all types of satellites, with at least one controller. &#10This method is not limited to YAW axis and can control the two other axes as well. One feature of this approach is the ability to be ...

In this article, a mixed robust/optimal control approach is proposed to treat the active vibration control (or active vibration suppression) problems of flexible structural systems under the effects of mode truncation, linear time-varying parameter perturbations and nonlinear actuators. A new robust stability condition is derived for the flexible structural system which is controlled by an obse...

In this work, we address the problem of global attitude control using direct inertial measurements. When using direct inertial measurement to observe the rigid body attitude, it is shown that due to a geometrical obstruction, it is impossible to achieve global asymptotic stability. In fact, for a particular initial condition the tracking error quaternion converges to a pure imaginary quaternion...

In this paper, an observer-based direct adaptive fuzzy-neural network (FNN) controller with supervisory mode for a certain class of high order unknown nonlinear dynamical system is presented. The direct adaptive control (DAC) has the advantage of less design effort by not using FNN to model the plant. By using an observer-based output feedback control law and adaptive law, the free parameters o...

This paper deals with the design of the minimal functional observer for linear time invariant systems. The proposed minimal functional observer estimates the linear function characterizing a state feedback controller law. A synthesis procedure of a minimum observer which has the same dimension as the control vector is then presented and a condition of such observer existence is stated. The effe...

This article proposes an observer-based current controller for virtual synchronous generators (VSG) in the presence of unmeasured and unpredictable loads. First, considered models are described, notably selected VSG model, as well grid-connected inverter. Then, proposed is detailed, which consists a linear quadratic regulator incorporating integrator state observer. Finally, experimental result...

Brushless Direct Current (BLDC) motors are widely used for high performance control applications. Conventional PID controller only provides satisfactory performance for set-point regulation. In this paper, a discrete time optimal tracking control of BLDC motor is presented. Modeling of the BLDC motor is expressed in state equation. A discrete time full-order state observer is designed to observ...

This paper deals with the problem of suppression of stick-slip oscillations in oil well drill-strings. The backstepping technique is used to design two control schemes for the system. The first controller is a typical backstepping controller; the second controller is a sliding back-stepping controller. Moreover, a reduced order observer is proposed to estimate the unmeasurable states of the sys...

This paper presents a design procedure for a reduced-order observer-based controller dedicated to n-joint robot manipulators. It is assumed that only the joint angular positions are measured. The joint angular velocities are estimated via an exponential reduced-order observer. Two types of control laws based on this observer are studied: point-to-point control with gravity compensation and traj...