PID Tuning of Plants With Time Delay Using Root Locus (original) (raw)
Related papers
A Comparative Study of Pid Controller Tuning Techniques for Time Delay Processes
2019
The Proportional-Integral-Derivative (PID) controllers are used in process/plant for controlling their parameters such as thermal or, electrical conductivity. By adjusting three parameters of PID controller, both transient and steady response can be improved, and better output can be obtained. There are many PID controller tuning techniques available in the literature and designing PID controllers for small delay processes with specified gain and phase margin is a well-known design technique. If the gain margin and phase margin are not specified, the system may not be optimum. A system with large gain and phase margins is more robust and gives better performance. When the system is robust, there will be no effect of slight changes in system parameters on the system performance. This paper describes a comparative analysis, among different types of tuning techniques available for first order plus delay time systems (FOPDT) on the basis of the various time integral performance criteria...
PID control design for first-order delay systems via MID pole placement: Performance vs. robustness
Automatica, 2022
The PID control is favored in controlling industrial processes for its ease of implementation. In this paper we present an analytical study, with an aim at stability robustness, tracking performance, and pole placement of first-order unstable plants under PID control. We employ a multiplicity-induced dominancy (MID) strategy to design and tune PID controller gains, which is shown to possess desirable properties that ensure specified decay rate of the closed-loop response and the stability robustness of the closed-loop system in spite of variations in the delay parameter. We also study the tradeoff between delay robustness and tracking performance of PID controllers. We show that under the constraint of steady-state tracking, the maximal delay robustness range can be computed by solving a unimodal pseudo-concave optimization problem.
International Journal of Automation and Control, 2020
To achieve satisfactory set-point tracking and load disturbance rejection, two approaches for PID controller design is presented in this paper. With a PD type controller, conventional IMC techniques fail to provide a satisfactory regulatory response for integrating processes and use of an integral action may lead to a large overshoot in servo response. To address this issue, a modified IMC structure with a second compensation for integrating processes is proposed to achieve desired servo as well as regulatory responses. Next, a frequency loop-shaping based design is proposed and the guidelines for choosing the desired loop-shape are also presented. To obtain the controller parameters in frequency loop-shaping framework, the optimisation problem is solved with primal-dual interior point method. To demonstrate the effectiveness of the proposed controllers, simulation comparisons with some recently developed methods are included. Moreover, the proposed method is experimentally validated on a temperature control process.
Insights on Pole-Placement of Dynamical Systems by PID Control with Guaranteed Delay Robustness
IFAC-PapersOnLine
The PID control is favored in controlling industrial processes for its ease of implementation. In this paper, the multiplicity-induced-dominancy property is used in the design of stabilizing PID controllers for some delayed reduced-order plants. More precisely, the controllers gains are tuned using the multiplicity's algebraic constraints allowing to assign analytically the closed-loop solutions' decay rate. Furthermore, the robustness of the control against uncertain delays is also addressed. An illustrative example completes the presentation.
Closed-Loop PI/PID Controller Tuning for Stable and Integrating Process with Time Delay
The objective of this study is to develop a new online controller tuning method in closed-loop mode. The proposed closed-loop tuning method overcomes the shortcoming of the well-known Ziegler-Nichols (1942) continuous cycling method and it can be an alternative for the same. This is a simple method to obtain the PI/PID setting which gives the acceptable performance and robustness for a broad range of the processes. The method requires a closed-loop step set-point experiment using a proportional only controller with gain Kc0. On the basis of simulations for a range of first-order with time delay processes, simple correlations have been derived to give PI/PID controller settings. The controller gain (Kc/Kc0) is only a function of the overshoot observed in the set-point experiment. The controller integral and derivative time (τI and τD) is mainly a function of the time to reach the first peak (tp). The simulation has been conducted for a broad class of stable and integrating processes, and the results are compared with a recently published paper of Shamsuzzoha and Skogestad (2010).1 The proposed tuning method gives consistently better performance and robustness for a broad class of processes.
International Journal of Advanced Science and Technology
Time delays are inherent in process industry. The presence of time delays limits and degrades the possible performance of the system and also leads to instability. The states of the delay system not only depend on the present state, they also depend on the previous states. With the help of a suitable controller design, the delay systems can be controlled for getting fruitful results. In all industrial feedback control applications most commonly and practically used controllers are Proportional Integral Derivative (PID) controllers. With proper parameter tuning of the controller, required performance can be achieved from the system. In general, the first order processes with time delay can be easily controlled with PI controllers. By choosing the proper controller gains the effect of time delays can be avoided. In this paper, PI controller design with Lambert W function analysis in smith configuration has been proposed. After the selection of dominant poles, the PI controller gains were chosen accordingly to shift the desired eigen values to required positions using the Lambert W function based analysis. A first order process with time delay has been considered in this paper and the comparative analysis of proposed tuning algorithm with Smith predictor (SP) and Zeigler-Nichols (ZN) methods has been done. By using the time response performance specifications and errors, the performance of different tuning algorithms has been analyzed. From the simulation and different performance indices results, it has been observed that proposed smith configured Lambert W based controller tuning approach gives improved results compared to remaining methods in terms of the measures like overshoot, peak time, settling time, rise time, errors etc.
Tuning of PID-type controllers for stable and unstable systems with time delay
1994
A graphical technique for tuning PID-type controllers based on the method of D-partition is proposed for single-input-single-output linear time invariant systems. The tuning method shifts all the roots of the characteristic equation of the controlled system to a certain desirable region in the left half of the complex plane (LHP) to achieve a specified least absolute and least relative stability margin. The method can be used to tune a precompensator, in a two degree of freedom structure, so as to improve tracking behaviour. The method can be used for both stable and unstable systems, for systems with significant time delay and for various controller configurations, including derivative in the feedback path.
Comparison of Pi Controller Performance for First Order Systems with Time Delay
2017
Delays appear often in all real world engineering systems. Delay systems have the property that the rate of variation in the system state depends on the previous states also. They are frequently a source of instability and poor system performance. In order to get the required performance from the delay system controller design plays a vital role. Because of the robust nature, easy structure Proportional Integral Derivative (PID) controllers are extensively used in many industrial loops. Parameter tuning of the PID controller is an essential task. Numerous industrial processes, whose transfer function is of first order, can be easily controlled with PI controllers. This paper presents the comparative analysis of an approach based on Lambert W function for PI controller design for first order systems with time delay among Smith predictor (SP) and ZeiglerNichols (ZN) methods of design. Performance of the considered methods in terms of various performance specifications through simulati...
A PID Controller Design Approach for Robust Stability of Arbitrary Order Plants with Time Delays
2015
A controller designed specifically for a nominal process model often works well for the nominal plant model, but may fail even by a little change in it. Robust control deals with analysis and controller design for such imperfect system with bounded modelling errors. A lot of research has been done and many methods are available for robust design of the plants. In this paper, a graphical technique is followed to find all PID controller gains that satisfy the robust stability constraint of a given DC motor model with time delay.