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Intelligent Mechatronic Model Reference Theory for Robot End-effector Control
Mohammad sadegh Dahideh,Mohammad Najafi,AliReza Zarei,Yaser Barmayeh,Mehran Afshar 보안공학연구지원센터(IJUNESST) 2015 International Journal of u- and e- Service, Scienc Vol.8 No.1
The control problem for manipulators is to determine the joint inputs required to case the end-effector execute the commanded motion. The nonminimum phase characteristic of a rigid manipulator makes the design of stable controller that ensures stringent tracking requirements a highly nontrivial and challenging problem. A useful controller in the computed torque family is the gravity controller. To compensate the dynamic parameters, fuzzy logic methodology is used and applied parallel to this method. When the arm is at rest, the only nonzero terms in the dynamic is the gravity. Proposed method can cancels the effects of the terms of gravity. In this case inorder to decrease the error and satteling time, higher gain controller is design and applied to nonlinear system.
Mohammad J. Zarei,Shahabeddin Hatami,Mohammad Gholami 국제구조공학회 2022 Steel and Composite Structures, An International J Vol.44 No.4
Sandwich structures with the superior mechanical properties such as high stiffness and strength-to-weight ratio, good thermal insulation, and high energy absorption capacity are used today in aerospace, automotive, marine, and civil engineering industries. These structures are composed of moderately stiff, thin face sheets that withstand the majority of transverse and in-plane loads, separated by a thick, lightweight core that resists shear forces. In this research, the finite element technique is used to simulate a sandwich panel with a truss core under axial compressive stress using ABAQUS software. A review of past experimental studies shows that the bondline between the core and face sheets plays a vital role in the critical failure load. Therefore, this modeling analyzes the damage initiation modes and debonding between face sheet and core by cohesive surface contact with traction-separation model. According to the results obtained from the modeling, it can be observed that the adhesive stiffness has a significant influence on the critical failure load of the specimens. To achieve the full strength of the structure as a continuum, a lower limit is obtained for the adhesive stiffness. By providing this limit stiffness between the core and the panel face sheets, sudden failure of the structure can be prevented.
Hajmohammad, Mohammad Hadi,Zarei, Mohammad Sharif,Farrokhian, Ahmad,Kolahchi, Reza Techno-Press 2018 Advances in nano research Vol.6 No.4
A layerwise shear deformation theory is applied in this paper for buckling analysis of piezoelectric truncated conical shell. The core is a multiphase nanocomposite reinforced by carbon nanotubes (CNTs) and carbon fibers. The top and bottom face sheets are piezoelectric subjected to 3D electric field and external voltage. The Halpin-Tsai model is used for obtaining the effective moisture and temperature dependent material properties of the core. The proposed layerwise theory is based on Mindlin's first-order shear deformation theory in each layer and results for a laminated truncated conical shell with three layers considering the continuity boundary condition. Applying energy method, the coupled motion equations are derived and analyzed using differential quadrature method (DQM) for different boundary conditions. The influences of some parameters such as boundary conditions, CNTs weight percent, cone semi vertex angle, geometrical parameters, moisture and temperature changes and external voltage are investigated on the buckling load of the smart structure. The results show that enhancing the CNTs weight percent, the buckling load increases. Furthermore, increasing the moisture and temperature changes decreases the buckling load.
Internal Combustion Engine Control Based on CFM Strategy
Ali Reza Zarei,Mohammad Sadegh Dahideh,Mohammad Najafi,Mehran Afshar,Yaser Barmayeh 보안공학연구지원센터 2015 International Journal of Hybrid Information Techno Vol.8 No.2
Internal combustion (IC) engines are optimized to meet exhaust emission requirements with the best fuel economy. The mean-value engine model can be used to validate control strategies for different types of controllers that are model-based. The equations that are used to calculate the outputs of the model are approximated over an engine cycle. A significant advantage of the mean-value engine model is its low computational throughput which makes it possible for real-time simulation. In order to reduce engine emissions and improving engine fuel economy, closed loop combustion control, which requires cycleto-cycle combustion measurement such as cylinder pressure, is a necessity. The addition of a cylinder pressure signal to a mean value engine model will allow for developing closed loop combustion control strategies (or other strategies that involve cylinder pressure) to be validated. This is because the cylinder pressure model can produce a cylinder pressure signal for a complete engine operational map and a mean value engine model can produce real world engine parameters and conditions. The performance of the baseline computed fuel controller is compared with that of a baseline proportional, integral, and derivative (PID) controller.
Air Pollution Reduction Based on Intelligent Nonlinear Control Methodology
Yaser Barmayeh,Mehran Afshar,Mohammad Sadegh Dahideh,Mohammad Najafi,Ali Reza Zarei 보안공학연구지원센터 2015 International Journal of Hybrid Information Techno Vol.8 No.1
This paper expands a Multi Input Multi Output (MIMO) fuzzy baseline control (FBC) which controller coefficient is off-line tuned by gradient descent algorithm. The main goal is to adjust the optimal value for fuel ratio (FR) in motor engine. The fuzzy inference system in proposed methodology is works based on Mamdani-Lyapunov fuzzy inference system (FIS). To reduce dependence on the gain updating factor coefficients of the fuzzy methodology, PID baseline method is introduced. This new method provides an optimal setting for other factors which created by PID baseline method. The gradient descent methodology is off-line tune all coefficients of baseline fuzzy based on mathematical optimization methodology. Simulation results signify good performance of fuel ratio in presence of different torque load and external disturbance.
Evaluating Performance and Applicability of Several Drought Indices in Arid Regions
Mohammad Mehdi Moghimi,Abdol Rassoul Zarei 한국기상학회 2021 Asia-Pacific Journal of Atmospheric Sciences Vol.57 No.3
Drought is a complex phenomenon that strong indices should be used to quantifying it. Reconnaissance drought index (RDI) is very strong index that extensively used in drought investigating researches. Major problem to calculate this index especially in arid and semi-arid regions at undeveloped countries is lack of data for calculating evapotranspiration. This study investigated this problem’s solution via simulating monthly RDI using other indices (PN, DI, SPI, CZI, MCZI and Z-Score) that in order to calculate these indices, only precipitation data is used. To simulate RDI, Generalized Estimating Equations (GEE) was used. For validation of estimating equations, different indices of goodness of fit were used (NSE, RMSE, MAE, R2, QIC and QICC). Results of this study indicated that the SPI, CZI, MCZI and DI indices had the most appropriateness for simulating RDI. When the SPI index (the best index for simulating RDI) was used to simulate the RDI, according to the results of T-Test, the observed and simulated data series hadn’t significantly difference (P value >0.05) in all stations. The average values of NSE, R2, RMSE, MAE, QIC and QICC obtained 0.976, 0.139, 0.088, 0.976, 21.24 and 17.82 sequential.
Chronic Pain and Its Determinants: A Population-based Study in Southern Iran
Zarei, Safar,Bigizadeh, Shiva,Pourahmadi, Mohammad,Ghobadifar, Mohamed Amin The Korean Pain Society 2012 The Korean Journal of Pain Vol.25 No.4
Background: Prevalence of chronic pain and its association with demographic characteristics have been reported by different studies from different geographical regions in the world. However, data from many Middle East countries including Iran (especially southern Iran) are scare. The aim of the present study was to demonstrate the prevalence of chronic pain and its association with demographic, psychological and socioeconomic factors in an Iranian population. Methods: In this population-based survey, the target population was comprised of subjects aged 20 to 85 years residing in Jahrom, southern Iran during 2009-2011. All eligible subjects were invited to participate in the study. Before a detailed questionnaire was given; face to face interviews were done for each individual. Results: There were 719 men and 874 women with an average age of 40.5 years at the onset of the study. Among the study population, 38.9% (620/1,593) complained of chronic pain, of whom 40.8% (253/620) were men and 59.2% (367/620) were women. Foot and joint pain were observed in 31.9%. Hip and spine pain, migraine and tension headaches, heart pain, and abdomen pain were observed in 21.5%, 15.5%, 9.5%, and 8.0% of chronic pain cases, respectively. There was a significant association among the covariables age, sex, overweight, educational level, income, and type of employment with chronic pain as the dependent variable (P < 0.0001). Conclusions: Our findings show the prevalence of chronic pain and its association with demographic, psychological and socioeconomic factors. Individuals with low incomes and less education became accustomed to pain due to a lack of knowledge.
Zarei, Seyed Amir,Akhtari, Keivan,Hassanzadeh, Keyumars,Piltan, Mohammad,Saaidpour, Saadi,Abedi, Marjan Korean Chemical Society 2013 대한화학회지 Vol.57 No.3
The geometry structures of hexa-coordinated [NiLX]X complexes ($X=Cl^-,\;Br^-,\;I^-$) {L = 8,9,18,19-tetrahydro-7H,17H-dibenzo[f,o] [1,5,9,13]dioxadiaza cyclohexadecine-8,18-diol} are optimized by density functional theory (DFT) using B3LYP/LANL2DZ. The calculated geometric parameters are in good agreement with the corresponding experimental values. Calculation results about these complexes show that dipole moment decreases, and the energy levels of HOMOs descend from iodo-complex to chloro-complex. The energy levels of HOMOs descend gently from iodo-complex to chloro-complex, while the energy levels of LUMOs in the present complexes are almost similar; therefore the energy gapes between HOMOs and LUMOs increased from iodo-complex to chloro-complex.