Adaptive robust steady-state tracking control

Author(s):  
V.F. Sokolov ◽  
S.M. Veres
Author(s):  
Y. Chida ◽  
R. Hara

In the present paper, we discuss a setpoint tracking control problem for a plant with discrete actuators. When a conventional linear servo controller is applied to the plant, undesirable periodic vibrations similar to the limit cycle occasionally occur in the output response caused by synergy with the integration of the steady-state tracking errors and the quantized errors of the control inputs. To prevent an undesirable response, a novel control method is proposed, in which the controller switches the control structure based on the value of the Lyapunov function. The effectiveness of the proposed method was verified through numerical simulations.


2021 ◽  
Vol 11 (3) ◽  
pp. 1211
Author(s):  
En-Chih Chang ◽  
Chun-An Cheng ◽  
Rong-Ching Wu

This paper develops a full-bridge DC-AC converter, which uses a robust optimal tracking control strategy to procure a high-quality sine output waveshape even in the presence of unpredictable intermissions. The proposed strategy brings out the advantages of non-singular fast convergent terminal attractor (NFCTA) and chaos particle swarm optimization (CPSO). Compared with a typical TA, the NFCTA affords fast convergence within a limited time to the steady-state situation, and keeps away from the possibility of singularity through its sliding surface design. It is worth noting that once the NFCTA-controlled DC-AC converter encounters drastic changes in internal parameters or the influence of external non-linear loads, the trembling with low-control precision will occur and the aggravation of transient and steady-state performance yields. Although the traditional PSO algorithm has the characteristics of simple implementation and fast convergence, the search process lacks diversity and converges prematurely. So, it is impossible to deviate from the local extreme value, resulting in poor solution quality or search stagnation. Thereby, an improved version of traditional PSO called CPSO is used to discover global optimal NFCTA parameters, which can preclude precocious convergence to local solutions, mitigating the tremor as well as enhancing DC-AC converter performance. By using the proposed stable closed-loop full-bridge DC-AC converter with a hybrid strategy integrating NFCTA and CPSO, low total harmonic distortion (THD) output-voltage and fast dynamic load response are generated under nonlinear rectifier-type load situations and during sudden load changes, respectively. Simulation results are done by the Matlab/Simulink environment, and experimental results of a digital signal processor (DSP) controlled full-bridge DC-AC converter prototype confirm the usefulness of the proposed strategy.


2018 ◽  
Vol 41 (3) ◽  
pp. 883-884 ◽  
Author(s):  
Seyed Majid Esmaeilzadeh ◽  
Mehdi Golestani

An adaptive control of MEMS gyroscopes with guaranteed transient and steady-state performance has been presented in Lu and Fei (2016). A performance function characterizing the convergence rate, maximum overshoot and steady-state error is used for the output error transformation, such that stabilizing the transformed system is sufficient to achieve the tracking control of the original system with a priori prescribed performance. The main objective of this comment is to point out a mistake occurred through the paper, resulted in the ineffectiveness of the proposed controller.


2016 ◽  
Vol 36 (4) ◽  
pp. 1725-1734 ◽  
Author(s):  
Azam Khalili ◽  
Amir Rastegarnia ◽  
Md Kafiul Islam ◽  
Tohid Yousefi Rezaii

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