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This paper presents an efficient numerical method to obtain optimal PI tuning formulae for first order plus dead time processes. The design method is based on optimal load disturbance rejection. In order to obtain a robust controller, a constraint on the maximum sensitivity is used. In addition, the design method deals with setpoint response using a two degree of freedom structure. In order to show...
PID control schemes still continue to be widely used for most industrial control systems. This is mainly because PID controllers have simple control structures, and are simple to maintain and tune. However, it is difficult to find a set of suitable control parameters in the case of time-varying and/or nonlinear systems. For such a problem, the robust controller has been proposed. Although it is important...
We present nonlinear model predictive control design for a type of discrete-time nonlinear system. Range constraints are imposed on input, output and input rate. When states are not available, an observer based on Newton's algorithm is used to estimate all states. We also present an idea to improve robustness of the control system when plant is subjected to modeling uncertainties. By using past information,...
A new robust AQM strategy for dynamically varying TCP/AQM networks is proposed. The developed AQM is designed based on coefficient diagram method (CDM), which is a new indirect pole placement approach that considers the speed, stability and robustness of the closed loop system in terms of the time domain specifications. Computer simulation results are presented to compare the performance of the proposed...
This paper discusses methodologies for designing limited lookahead supervisory controllers for a class of embedded systems that can be modeled as switching hybrid system (SHS). In the limited lookahead control approach, a limited forward horizon of possible behaviors is explored at each time step. The controller uses a cost function to determine the immediate action that moves the system toward the...
Model predictive control (MPC) based on mixed logical dynamical (MLD) systems was proposed as a suitable approach to the control problem of hybrid systems. In this paper, we study some extensions of the basic structure in order to gain precision in the regulation problem. We study the robustness of the resulting controlled system using simulations of a three-tank benchmark
Static synchronous compensator (STATCOM) controls are known to enhance damping of a power system. The graphical loop-shaping procedure used in designing a robust STATCOM controller can be significantly improved by embedding some optimization procedure in it. In this article a particle swarm optimization (PSO) technique has been employed to find the fixed parameter robust controller parameters. PSO...
For linear systems with structured uncertainties, the unknown input fault detection observer (UIFDO) provides a robust diagnostic approach by decoupling the fault signals from the unknown input term. However, in real applications, detection performance of the UIFDO degrades seriously as nonlinearities become significant in a wide dynamic operating range. In this paper, a novel UIFDO design and the...
This paper deals with fault detection observer design for linear time-invariant systems with unknown inputs. The design objective is set to minimize a combined performance index Hinfin/H- which means to achieve a good compromise between robustness to the disturbance and sensitivity to the fault. Hence, the fault detection observer is designed to detect the fault of smallest energy possible. In this...
A nonlinear adaptive-robust scheme is presented to control a class of nonlinear systems. It effectively combines the design techniques of adaptive and robust control to improve performance by retaining the advantages of both techniques. It enhances transient performance and eliminates robustness problems compared to a parameter adaptive control. It also improves tracking performance by reducing modeling...
This paper develops a nonlinear backstepping design for the control of rotary drilling system, in order to arrive at a robust controller capable of dealing with the torsional oscillations (stick-slip). This work is motivated by the complex problem of the nonlinearity in drillstring, which is rotated at a constant angular velocity by an electric motor, but exhibits superimposed torsional vibrations...
This paper demonstrates a good application of SDRE technology to propose optimal controllers for a flexible transporter system with arbitrarily varying lengths. A model for a flexible cable transporter system with varying cable lengths is developed using Hamilton's principle. Galerkin's method is applied to transform the infinite dimensional system into a set of finite dimensional ordinary differential...
This paper presents a new approach for the synthesis of robust digital guidance. The resulting guidance laws achieve stable and accurate missile guidance despite parametric uncertainties in the missile flight control system dynamics, prescribed limits on missile acceleration, and digital implementation at possibly slow sampling rates. A robust continuous-time guidance law is first designed using mixed...
The control logic of a modern jet engine consists of many control loops and the design of control system must account for the uncertainties in the model. In both commercial and military jet engines, the complexity of control system results in a series of single input single output controllers. In this paper, a new approach using interval analysis is proposed for design of a robust compensator for...
Input shaping technique is well used for reducing residual vibrations of flexible systems. However, the strategies of both the time domain and the vector diagram are complex to improve the robustness of an input shaper. Zero placement method in the z-plane is utilized to design multi-hump robust input shapers. Two or more shaper zeros are placed nearby the system pole to work out the typical symmetric...
Active vibration control is one of the interesting problems for control engineers. The problem is tackled by making a smart, adaptive and self-controlling structure that requires robust controller. The newly invented second order sliding mode controller (SSMC) not only retains the robustness properties of the classical sliding mode controller (SMC) but also eliminates the drawback of the SMC that...
The control of dynamical systems with inherent non-linear characteristics has motivated research in non-linear control theory. Two main approaches to dealing with uncertainties in control systems design are adaptive and robust control. In this paper, discrete direct adaptive control of unknown non-linear SISO systems is considered. The controller is implemented using a fuzzy neural network. The control...
In this paper, switching control of linear time-invariant systems using generalized sampled-data hold functions is investigated. It is assumed that the plant model belongs to a finite set of known plants. The output of the system is periodically sampled and a control signal is being generated by means of a suitable hold function which solves the robust servomechanism problem for a family of plant...
The problem of designing a robust dynamical controller for solving the tracking control problem for a flexible-link manipulator is studied. The design methodology is based on construction of a two-time scale dynamical motion of the closed-loop system. It is shown that for a sufficiently small perturbation parameter associated with the dynamical controller consisting of high order derivatives of the...
In this paper, we elaborate a sliding mode control from a simplified linear model of a heavyweight torpedo. Then, we use this control law with the torpedo's nonlinear model in order to evaluate the robustness of the control law in relation to the parametric uncertainties of the model (the hydrodynamics coefficients...), and to the sea current's perturbation. The development of the first and second...
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