A study of phase/frequency-locked servo system by fuzzy control technique

Tower cranes are very complex mechanical systems and have been the subject of research investigations for several decades. Research on tower cranes has focused on the development of dynamical models (linear and nonlinear) as well as control techniques to reduce the swaying of the payload. Inherently, the dynamical model of the tower crane is highly nonlinear and classified as under-actuated. The crane system has potentially six degrees of freedom but only three actuators. Also, the actuators are far from the payload which makes the system non-colocated. The dynamic model describing the motion of the payload from point to point is affected by uncertainties, time delays and external disturbances which may lead to inaccurate positioning, reduce safety and efficacy of the overall system. It is proposed here to use an H∞ based adaptive fuzzy control technique to control the swaying motion of a tower crane. This technique will overcome modeling inaccuracies, such as drag and friction losses, effect of time delayed disturbances, as well as parameter uncertainties. The proposed control law for payload positioning is based on indirect adaptive fuzzy control. A fuzzy model is used to approximate the dynamics of the tower crane; then, an indirect adaptive fuzzy scheme is developed for overriding the nonlinearities and time delays. The advantage of employing an adaptive fuzzy system is the use of linear analytical results instead of estimating nonlinear system functions with an online update law. The adaptive fuzzy scheme fuses a Variable Structure (VS) scheme to resolve the system uncertainties, and the external disturbances such that H∞ tracking performance is achieved. A control law is derived based on a Lyapunov criterion and the Riccati-inequality to compensate for the effect of the external disturbances on tracking error so that all states of the system are uniformly ultimately bounded (UUB). Therefore, the effect can be reduced to any prescribed level to achieve H∞ tracking performance. Simulations are presented here to illustrate the performance of the proposed control design.

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Fuzzy Control of the Permanent Magnet Synchronous Machine Singularly Perturbed Fed By a Three Level Inverter

Journal of Electrical Engineering ◽

10.2478/v10187-012-0027-5 ◽

2012 ◽

Vol 63 (3) ◽

pp. 186-190 ◽

Cited By ~ 2

Author(s):

Ahmed Massoum ◽

Abdelkader Meroufel ◽

Patrice Wira ◽

Mohammed Fellah

Keyword(s):

Fuzzy Control ◽

Permanent Magnet ◽

Perturbation Technique ◽

Digital Simulation ◽

Synchronous Machine ◽

Singularly Perturbed ◽

Control Technique ◽

Permanent Magnet Synchronous Machine ◽

Singular Perturbation Technique ◽

Decoupled Control

Fuzzy Control of the Permanent Magnet Synchronous Machine Singularly Perturbed Fed By a Three Level InverterIn this paper, we present the control technique based on the singular perturbation technique controlled by a fuzzy regulator applied to the permanent magnet synchronous machine (PMSM). This technique applied to the PMSM conducts to a separation of the variables into disjoined subset or two separated models: one having a slow dynamics, and the other a fast dynamics. To ensure certain robustness to the decoupled control system based on these techniques, the control speed and theIdcurrent is carried out by fuzzy regulators. A qualitative analysis of the principal variables evolution describing the behavior of the global system (PMSM-Inverter with MLI-Control) and its robustness is developed by several tests of digital simulation in last stage.

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