Fuzzy Modeling of a Piezoelectric Actuator

Morteza Mohammadzaheri,Steven Grainger,Mohsen Bazghaleh 한국정밀공학회 2012 International Journal of Precision Engineering and Vol. No.

In this research, a piezoelectric actuator was modeled using fuzzy subtractive clustering and neuro-fuzzy networks. In the literature, the use of various modeling techniques (excluding techniques used in this article) and different arrangements of inputs in black box modeling of piezoelectric actuators for the purpose of displacement prediction has been reported. Nowadays, universal approximators are available with proven ability in system modeling; hence, the modeling technique is no longer such a critical issue. Appropriate selection of the inputs to the model is, however, still an unsolved problem, with an absence of comparative studies. While the extremum values of input voltage and/or displacement in each cycle of operation have been used in black box modeling inspired by classical phenomenological methods, some researchers have ignored them. This article focuses on addressing this matter. Despite the fact that classical artificial neural networks, the most popular black box modeling tools, provide no visibility of the internal operation, neuro-fuzzy networks can be converted to fuzzy models. Fuzzy models comprise of fuzzy rules which are formed by a number of fuzzy or linguistic values,and this lets the researcher understand the role of each input in the model in comparison with other inputs, particularly, if fuzzy values (sets) have been selected through subtractive clustering. This unique advantage was employed in this research together with consideration of a few critical but subtle points in model verification which are usually overlooked in black box modeling of piezoelectric actuators.

Double-command fuzzy control of a nonlinear CSTR

Morteza Mohammadzaheri,Lei Chen 한국화학공학회 2010 Korean Journal of Chemical Engineering Vol.27 No.1

In this research, double-command control of a nonlinear chemical system is addressed. The system is a stirred tank reactor; two flows of liquid with different concentrations enter the system through two valves and another flow exits the tank with a concentration between the two input concentrations. Fuzzy logic was employed to design a model-free double-command controller for this system in the simulation environment. In order to avoid output chattering and frequent change of control command (leading to frequent closing-opening of control valves, in practice) a damper rule is added to the fuzzy control system. A feedforward (steady state) control law is also derived from the nonlinear mathematical model of the system to be added to feedback (fuzzy) controller generating transient control command. The hybrid control system leads to a very smooth change of control input, which suits real applications. The proposed control system offers much lower error integral, control command change and processing time in comparison with neuro-predictive controllers.

Double-command feedforward-feedback control of a nonlinear plant

Morteza Mohammadzaheri,Lei Chen 한국화학공학회 2010 Korean Journal of Chemical Engineering Vol.27 No.5

A design approach is proposed for feedforward-feedback control systems. The basis of the proposed approach is a steady state control law which maintains the desired control output of the system and is employed as the feedforward controller. With this feedforward controller, for a wide class of systems, the stability of the control system is proved if the feedback controller is a gain with an arbitrarily high value; that is, the only limit for the feedback (transient)control command is the actuator’s practical limit. Moreover, in continuous domain, there will be no overshoot. In this article, the proposed method has been applied to a catalytic stirred tank reactor (CSTR) to control the output concentration through adjusting the flow of two valves simultaneously and resulted in an excellent control response.

Fault diagnosis of an automobile cylinder head using low frequency vibrational data

Maryam Taajobian,Morteza Mohammadzaheri,Mojtaba Doustmohammadi,Amirhosein Amouzadeh,Mohammadreza Emadi 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.7

This paper proposes a vibration-based fault-diagnosis method for mechanical parts. This method, after algorithm development, only requires a single inexpensive test to inspect the part which could take as short as half a second. The algorithm is developed in three major stages, (i) exciting specimens without or with known faults using a controlled force and recording acceleration of a single point for a short time (ii) finding a signature for each faulty specimen, using Fourier transform and statistical analysis. (iii) Developing a multi-layer perceptron, as a mathematical model, using the results of stage (ii). The elements of a part signature are the inputs to the model. The location (and possibly size and shape factor) of the fault is model output. Stage (i) can be performed experimentally or alternatively with a validated FEM, one experiment or simulation per specimen. The proposed technique was examined to locate (isolate) a fault on an automobile cylinder head. The presented accuracy is considerable, and the data collected at fairly low frequency range (below 1200 Hz) were found to be sufficient for this technique. In the case study of this paper, possible fault locations are on a line; as a result, fault location has one dimension. It is shown that the technique can be extended to higher dimensions.

A fuzzy virtual temperature sensor for an irradiative enclosure

Dalileh Mehrabi,Morteza Mohammadzaheri,Ali Firoozfar,Mohammadreza Emadi 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.10

This paper presents the idea of virtual temperature sensors for irradiative enclosures. Such a virtual sensor is an algorithm which receives the temperature of a number of points on surfaces of an enclosure and estimates the temperature of another point (or a number of other points) within enclosure. This paper proposes a data-driven method based on fuzzy inference systems to develop temperature virtual sensing algorithms. The proposed method is validated on an experimental setup exhibiting excellent estimation accuracy with no need to thermo-physical properties of the enclosure. In this research, the designed and validated algorithm estimates the temperature of a single point; however, the methodology can be evidently extended to multiple points.

Dynamic analysis and performance optimization of permendur cantilevered energy harvester

Mojtaba Ghodsi,Hamidreza Ziaiefar,Morteza Mohammadzaheri,Farag K. Omar,Issam Bahadur 국제구조공학회 2019 Smart Structures and Systems, An International Jou Vol.23 No.5

The development of the low power application such as wireless sensors and health monitoring systems, attract a great attention to low power vibration energy harvesters. The recent vibration energy harvesters use smart materials in their structures to convert ambient mechanical energy into electricity. The frequent model of this harvesters is cantilevered beam. In the literature, the base excitation cantilevered harvesters are mainly investigated, and the related models are presented. This paper investigates a tip excitation cantilevered beam energy harvester with permendur. In the first section, the mechanical model of the harvester and magneto-mechanical model of the permendur are presented. Later, to find the maximum output of the harvester, based on the response surface method (RSM), some experiments are done, and the results are analyzed. Finally, to verify the results of RSM, a harvester with optimum design variables is made, and its output power is compared. The last comparison verifies the estimation of the RSM method which was about 381 uW/cm3. The development of the low power application such as wireless sensors and health monitoring systems, attract a great attention to low power vibration energy harvesters. The recent vibration energy harvesters use smart materials in their structures to convert ambient mechanical energy into electricity. The frequent model of this harvesters is cantilevered beam. In the literature, the base excitation cantilevered harvesters are mainly investigated, and the related models are presented. This paper investigates a tip excitation cantilevered beam energy harvester with permendur. In the first section, the mechanical model of the harvester and magneto-mechanical model of the permendur are presented. Later, to find the maximum output of the harvester, based on the response surface method (RSM), some experiments are done, and the results are analyzed. Finally, to verify the results of RSM, a harvester with optimum design variables is made, and its output power is compared. The last comparison verifies the estimation of the RSM method which was about 381 µW/cm3.