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In industrial control processes, it requires fast response for transient state and for steady state it is necessary to maintain user-specified control performance to achieve desired productivity. Moreover, the Proportional-Integral-Derivative(PID) control algorithm is widely used in industrial control processes. Hence, in this paper an algorithm to tune PID control parameters that can improve control...
Conventional controllers with fixed tuning fail to perform satisfactorily for processes with time varying nature. In such cases adaptive controllers are preferred as they are capable to provide suitable corrective measure according to the changes of process dynamics and undesired process upsets. In model reference adaptive control (MRAC) desired process output specifications are provided in the form...
Repetitive control (RC) is a widely used effective approach for periodic reference tracking and periodic disturbance rejection. In this paper, its use for periodic disturbance rejection and piecewise constant reference tracking is analyzed in a continuous-time framework. First, two previously proposed repetitive control structures, namely the basic repetitive controller and the current iteration repetitive...
Fuzzy logic controllers (FLCs) utilize fuzzy logic to convert the linguistic control strategy based on expert knowledge into an automatic control strategy. The dynamic of nonlinear processes can be easy controlled using FLCs. The paper presents a method to design the structure of a fuzzy logic controller (FLC) based on decision tables. To achieve the proposed FLC the mathematical models of the nonlinear...
This paper discusses the online technique to estimate the process frequency response without breaking the closed-loop control. The extended method of relay feedback using fast Fourier transform (FFT) is measured input and output responses without disconnecting the controller from the loop, which significantly reduces the time required for the autotuning test. The method utilizes step response information...
Control performance and cost optimization can be conflicting goals in the management of industrial processes. Even when optimal or optimization-based control synthesis tools are applied, the economic cost associated with plant operation is often only optimized according to static criteria that pick, among all feasible steady states, those with minimal cost. In mathematical terms, an economic cost...
Predictive controllers are used frequently with PI backup controllers. As the two algorithms (PI and predictive) are different a switch between them can cause big jumps. A bumpless switch is a very important issue. A smooth switch is desired to avoid any discontinuity in the manipulated and the controlled variables. A common strategy is to let run the backup controller in such a way that the calculated...
Industrial processes are characterized by changing dynamics associated to different operating points. Control systems usually face this behavior by adapting the control parameters or switching among controllers, in order to achieve high performance of the system in the whole process operation range. Different methods have been developed to avoid undesirable transients in the closed loop output signal...
A modification of Smith predictor for controlling the higher order processes with integral action & long dead-time is proposed in this paper. The controller used in this Smith predictor is an Integral-Proportional Derivative controller, where the Integrator is in the forward path & the Proportional and Derivative control are in the feedback, acting on the feedback signal. The main objective...
This paper describes the adaptive prediction and control of a non-linear process with time delay. The process can be described approximately by a non-minimum phase linear system with time varying coefficients. An adaptive control strategy is needed to adapt to time-varying behavior of the process. An adaptive prediction and control scheme is used to accomplish this objective. Algorithms are described,...
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