Disturbance Rejection In Linear Systems Research Articles

Event-triggered equivalent-input-disturbance estimation and control for disturbance attenuation

A novel three-channel event-triggered equivalent-input-disturbance (EID) estimation approach is proposed for active exogenous disturbance rejection in linear systems. The overall system governing equations consisting of the physical plant, disturbance estimator, internal model, and event-triggering mechanisms (ETMs) are modeled as an augmented closed-loop system with multiple time-varying delays using an input delay method. Sufficient conditions for asymptotic stability of the augmented closed-loop system are derived together with a procedure for co-designing the controller and state observer gains and the ETM parameters that satisfy the sufficient conditions for asymptotic stability. Numerical simulations on a DC motor system are provided to illustrate the effectiveness and potential of the proposed design approach.

Observer‐based disturbance rejection for linear systems by aperiodical sampling control

This paper is devoted to introduce integral-based triggering condition to design the observer-based controller for linear systems with disturbances. A model-based form is employed to generate the control signals. Based on the different cases of communication channels, the controller and the observer are implemented by three different architectures. Furthermore, for all the architectures, the designed closed-loop systems satisfy a prescribed L 2 − L ∞ performance and exclude Zeno behaviour. Finally, a numerical example is provided to illustrate the efficiency and the feasibility of the proposed results.

Rejection of Periodic Wind Disturbances on a Smart Rotor Test Section Using Lifted Repetitive Control

A repetitive control method is presented that is implemented in real-time for periodic wind disturbance rejection for linear systems with multiple inputs and multiple outputs and with both repetitive and non-repetitive disturbance components. The novel repetitive controller can reject the periodic wind disturbances for fixed-speed wind turbines and variable-speed wind turbines operating above-rated and we will demonstrate this on an experimental “smart” rotor test section. The “smart” rotor is a rotor where the blades are equipped with a number of control devices that locally change the lift profile on the blade, combined with appropriate sensors and controllers. The rotational speed of wind turbines operating above-rated will vary around a defined reference speed, therefore methods are given to robustify the repetitive controllers for a mismatch in the period. The design of the repetitive controller is formulated as a lifted linear stochastic output-feedback problem on which the mature techniques of discrete linear control may be applied. For real-time implementation, the computational complexity can be reduced by exploiting the structure in the lifted state-space matrices. With relatively slow changing periodic disturbances it is shown that this repetitive control method can significantly reduce the structural vibrations of the “smart” rotor test section. The cost of additional wear and tear of the “smart” actuators are kept small, because a smooth control action is generated as the controller mainly focuses on the reduction of periodic disturbances.

On the Design of Robust Disturbance Observers for Mechatronic Systems

High speed and high accuracy mechanical systems pose an increasing demand on the control systems to eliminate the influence of disturbances like cogging and friction. One way to incorporate additional disturbance rejection for linear systems is to extend the controller with a disturbance observer. By virtue of the separation property, the disturbance observer and the controller can be designed separately.In this paper, an overview is given of choices to be made to design a disturbance observer, and the consequences of every step are discussed. It follows that, despite the separation property, knowledge about the feedback controller is needed to design the disturbance observer (and vice versa), in order to guarantee robust stability. Existing disturbance observer design techniques are extended to account for model uncertainty. Experimental results on a linear permanent magnet motor demonstrate the effectiveness and robustness of the disturbance observer design method.

Simultaneous Decoupling and Disturbance Rejection for Systems Modelled by Bond Graph

The aim of this paper is to solve the combined problem of decoupling and disturbance rejection for linear systems modelled by bond graph. A graphical characterization of the infinite structure is proposed in terms of input-output causal paths in the associated bond graph model. Then we derive directly on the bond graph model necessary and sufficient conditions for the existence of a state feedback controller that rejects the disturbances and simultaneously decouples the closed loop system.

Adaptive quantization: solution via nonadaptive linear control

A common nonlinear adaptive quantization problem is posed as a corresponding linear quadratic control problem. Adaptive quantizer algorithms are generated using methods of disturbance rejection in linear systems. Simulation with speech data shows that these algorithms can outperform a previous well-known method. The new approach subsumes and extends previous algorithms in a logical fashion. >

Necessary conditions for optimal disturbance rejection in linear systems

Disturbance rejection is an important factor in the synthesis of controllers for several practical systems. In this paper we derive necessary conditions which need to be satisfied by the controller in order to yield maximum disturbance rejection. Necessary conditions for maximum disturbance rejection are also derived in the case of an observer-based controller. These conditions are useful in the synthesis of a controller that maximizes the disturbance rejection capacity of the system. The problem considered has connections to H∞ control theory. An example is given.

Comment on ‘ Disturbance rejection in linear systems ’

Comment on ‘ Disturbance rejection in linear systems ’

Disturbance rejection in linear systems †

The problem of making the transfer function between disturbances and controlled outputs identically zero by using state feedback, feedforward control and dynamic compensation in u linear timo invariant system is treated and a constructive solve ability condition is presented.