Tuning of Fractional Order Controller and Prefilter in MIMO Robust Motion Control: SCARA Robot

Author(s):  
Mohamed Allagui ◽  
Najah Yousfi ◽  
Nabil Derbel ◽  
Pierre Melchior

Designing and automation of a robust controller and pre-filter for multi-variable processes are a very challenging task. In this study, an automated and simple conception of multivariable QFT (QFT: Quantitative Feedback Theory) is proposed using fractional order controllers design. Contrary to the traditional manual QFT design, our methodology consists of obtaining all required performances in QFT without going to the QFT loop shaping process.A non-integer order proportional derivative controller PDµ is conceived for a robust control of MIMO (Multi Input Multi Out- put) systems through multi-objective optimization based genetic algorithm . In the designed approach an implicit fractional order pre-filter FBLFD (FBLFD : Frequency Band Limited Fractional Differentiator) is adopted and its parameters are optimized. A diagonal version of this fractional order pre-filter and a non diagonal one are proposed. The problem of loop interactions is eliminated by the non diagonal designed pre-filter. Consequently, the procedure of fractional controller and pre-filter parameters optimization is illustrated. A comparative study and the efficiency of the developed methodologies are considered through SCARA robot.


2021 ◽  
Vol 4 (3) ◽  
pp. 50
Author(s):  
Preeti Warrier ◽  
Pritesh Shah

The control of power converters is difficult due to their non-linear nature and, hence, the quest for smart and efficient controllers is continuous and ongoing. Fractional-order controllers have demonstrated superior performance in power electronic systems in recent years. However, it is a challenge to attain optimal parameters of the fractional-order controller for such types of systems. This article describes the optimal design of a fractional order PID (FOPID) controller for a buck converter using the cohort intelligence (CI) optimization approach. The CI is an artificial intelligence-based socio-inspired meta-heuristic algorithm, which has been inspired by the behavior of a group of candidates called a cohort. The FOPID controller parameters are designed for the minimization of various performance indices, with more emphasis on the integral squared error (ISE) performance index. The FOPID controller shows faster transient and dynamic response characteristics in comparison to the conventional PID controller. Comparison of the proposed method with different optimization techniques like the GA, PSO, ABC, and SA shows good results in lesser computational time. Hence the CI method can be effectively used for the optimal tuning of FOPID controllers, as it gives comparable results to other optimization algorithms at a much faster rate. Such controllers can be optimized for multiple objectives and used in the control of various power converters giving rise to more efficient systems catering to the Industry 4.0 standards.


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