Validation of a multivariable relay-based PID autotuner with specified robustness

C

Application of iterative feedback tuning

Master'sMASTER OF ENGINEERIN

Universal direct tuner for loop control in industry

This paper introduces a direct universal (automatic) tuner for basic loop control in industrial applications. The direct feature refers to the fact that a first-hand model, such as a step response first-order plus dead time approximation, is not required. Instead, a point in the frequency domain and the corresponding slope of the loop frequency response is identified by single test suitable for industrial applications. The proposed method has been shown to overcome pitfalls found in other (automatic) tuning methods and has been validated in a wide range of common and exotic processes in simulation and experimental conditions. The method is very robust to noise, an important feature for real life industrial applications. Comparison is performed with other well-known methods, such as approximate M-constrained integral gain optimization (AMIGO) and Skogestad internal model controller (SIMC), which are indirect methods, i.e., they are based on a first-hand approximation of step response data. The results indicate great similarity between the results, whereas the direct method has the advantage of skipping this intermediate step of identification. The control structure is the most commonly used in industry, i.e., proportional-integral-derivative (PID) type. As the derivative action is often not used in industry due to its difficult choice, in the proposed method, we use a direct relation between the integral and derivative gains. This enables the user to have in the tuning structure the advantages of the derivative action, therefore much improving the potential of good performance in real life control applications

DC motorun otomatik ayarlamalı PID ile hız kontrolünün gerçekleştirilmesi

Although advanced controllers are used in control applications, proportional-integral-derivative (PID) controllers are preferred in industry due to their simple structure and ease of application. However, it can difficult to set these controller parameters for the controlled platform. These parameters tuning with trial-error method leads to time and job loss, and the parameters determined in this way cannot provide a sufficiently efficient operating characteristic. In order to overcome this problem related to PID parameter tuning many automatic tuning methods have been developed. In this paper, the automatic tuning method proposed by Aström and Hagglund was applied to a DC motor speed control system. The DC motor speed control system was implemented in an interface designed on Laboratory Virtual Instrument Electronic Workbench (LabVIEW) environment and CompactRIO unit. The PID parameters obtained with trial-error and two types auto-tuning methods were tested in the DC motor control system and achieved results were compered. The results showed that performance of the PID controller tuned with LAbVIEW auto-tuning method is better than others.Kontrol uygulamalarında gelişmiş kontrolörler kullanılsa da PID (Proportional-Integral-Derivative) kontrolörler basit yapısından ve kolay uygulanabildiğinden dolayı endüstride tercih edilmektedir. Ancak kontrol edilecek platforma uygun PID parametrelerinin ayarlanması oldukça güç olabilmektedir. Bu parametrelerin deneme yanılma yöntemiyle ayarlanması zaman ve iş kaybına sebep olmakla birlikte bu yolla tespit edilen parametrelerle ayarlanan kontrolörler yeterince verimli bir çalışma karakteristiği sunmayabilmektedir. PID parametrelerinin ayarıyla ilgili bu sorunların üstesinden gelebilmek için çok sayıda otomatik ayar yöntemi geliştirilmiştir. Bu makalede Åström ve Hägglund tarafından önerilen otomatik ayar yöntemi bir DC motoru hız kontrol sistemine uygulanmıştır. Bu DC motor hız kontrol sistemi LabVIEW (Laboratory Virtual Instrument Electronic Workbench) ortamında geliştirilen ara yüz ve CompactRIO ünitesi üzerinde gerçekleştirilmiştir. Deneme yanılma ve iki farklı otomatik ayarlama yöntemiyle elde edilen PID parametreleri DC motor kontrol sistemi üzerinde denenmiş ve elde edilen sonuçlar karşılaştırılmıştır. Sonuçlar, LabVIEW otomatik ayarlama yöntemiyle elde edilen parametrelerle işletilen PID kontrolörün daha iyi performans gösterdiğini göstermişti

PI/PID Controller Relay Experiment Auto-Tuning with Extended Kalman Filter and Second-Order Generalized Integrator as Parameter Estimators

This paper presents a method for the estimation of key parameters of limit cycle oscillations (amplitude and frequency) during a relay experiment used for automatic tuning of proportional-integral (PI) and proportional-integral-derivative (PID) feedback controllers. The limit cycle parameter estimator is based on the first-order extended Kalman filter (EKF) for resonance frequency estimation, to which a second-order generalized integrator (SOGI) is cascaded for the purpose of limit cycle amplitude estimation. Based on thus-obtained parameters of the limit cycle oscillations, the ultimate gain and the ultimate period of the limit cycle oscillations are estimated. These are subsequently used for the tuning of PI and PID controller according to Takahashi modifications of Ziegler-Nichols tuning rules. The proposed PI and PID controller auto-tuning method is verified by means of simulations and experimentally on the heat and air-flow experimental setup for the case of air temperature feedback control. The results have shown that the proposed auto-tuning system based on relay control experiment for the heat and air-flow process PI/PID temperature control can capture the ultimate gain and period parameters fairly quickly in simulations and in experiments. Subsequent controller tuning according to Takahashi modifications of Ziegler-Nichols rules using thus-obtained ultimate point parameters can provide favourable closed-loop load disturbance rejection, particularly in the case of PID controller

PI/PID Controller Relay Experiment Auto-Tuning with Extended Kalman Filter and Second-Order Generalized Integrator as Parameter Estimators

This paper presents a method for the estimation of key parameters of limit cycle oscillations (amplitude and frequency) during a relay experiment used for automatic tuning of proportional-integral (PI) and proportional-integral-derivative (PID) feedback controllers. The limit cycle parameter estimator is based on the first-order extended Kalman filter (EKF) for resonance frequency estimation, to which a second-order generalized integrator (SOGI) is cascaded for the purpose of limit cycle amplitude estimation. Based on thus-obtained parameters of the limit cycle oscillations, the ultimate gain and the ultimate period of the limit cycle oscillations are estimated. These are subsequently used for the tuning of PI and PID controller according to Takahashi modifications of Ziegler-Nichols tuning rules. The proposed PI and PID controller auto-tuning method is verified by means of simulations and experimentally on the heat and air-flow experimental setup for the case of air temperature feedback control. The results have shown that the proposed auto-tuning system based on relay control experiment for the heat and air-flow process PI/PID temperature control can capture the ultimate gain and period parameters fairly quickly in simulations and in experiments. Subsequent controller tuning according to Takahashi modifications of Ziegler-Nichols rules using thus-obtained ultimate point parameters can provide favourable closed-loop load disturbance rejection, particularly in the case of PID controller

Tuning and auto-tuning of fractional order controllers for industry applications

This paper deals with the design of fractional order PI²Dμ controllers, in which the orders of the integral and derivative parts, λ and μ, respectively, are fractional. The purpose is to take advantage of the introduction of these two parameters and fulfill additional specifications of design, ensuring a robust performance of the controlled system with respect to gain variations and noise. A method for tuning the PI²Dμ controller is proposed in this paper to fulfill five different design specifications. Experimental results show that the requirements are totally met for the platform to be controlled. Besides, this paper proposes an auto-tuning method for this kind of controller. Specifications of gain crossover frequency and phase margin are fulfilled, together with the iso-damping property of the time response of the system. Experimental results are given to illustrate the effectiveness of this method