System identification and modeling of gyro-stabilized IR/EO gimbal system in frequency domain /

Download
2014
Özdoğan, Gökhan
The field of system identification takes a fundamental place in control engineering. In order to design an efficient robust controller, one requires an accurate mathematical model with its uncertainty for the dynamical system of interest. It is crucial that experiments are well designed so that parameters to be estimated through statistical methods result in least possible bias and minimum variance. In this study, four axes gyro stabilized Infrared Electro Optic gimbal system is modeled in the frequency domain through experimental investigation. The input and output signals are logged using xPC Target of MATLAB with a sampling frequency of 3kHz. The communication with real system is realized with RS-422 protocol. In system identification, the first step is experiment design. Various perturbation signals are analyzed and compared. A cost function is offered to optimize power spectrum for the input excitation signal while satisfying device specific constraints. Second step is frequency response function measurement. By averaging techniques, it is possible to reduce the variance of frequency response function measurement and decrease the error. Moreover, the averaging in the frequency domain provides the nonparametric noise model of the system. Periodic excitation signals are used and an integer number of signal periods have been measured. Before passing to the next step, a robust method to detect and quantify nonlinear distortion on frequency response functions measurements is studied. In the final step, real system is modeled by its parametric transfer function with plenty of different estimation techniques and their efficiencies, convergence properties, bias errors are compared and discussed.

Suggestions

A Control System Architecture for Control of Non-Affine in Control, Open-Loop Unstable Underactuated Systems
Marangoz, Alp; Kutay, Ali Türker (2017-07-25)
In this paper, a control system architecture for control of non-affine in control, open-loop unstable underactuated system is discussed. Passivization of the unactuated (internal) system dynamics achieved through perturbation of trajectories of the actuated states, which are calculated through adaptive dynamic inversion technique, based on Tikhonov's theorem. Performance of the controller is shown through simulation of two open-loop unstable and locally uncontrollable example problems.
Model Updating of a Nonlinear System: Gun Barrel of a Battle Tank
Canbaloglu, Guvenc; Özgüven, Hasan Nevzat (2016-01-28)
Nonlinearities in a structural system make the use of model updating methods developed for linear systems difficult to apply nonlinear systems. If the FRFs of the underlying linear systems in a nonlinear system could be experimentally extracted, then the linear model updating methods could easily be applied to nonlinear systems as well. When there are complex nonlinearities in a structure together with frictional type of nonlinearity, linear FRFs cannot be accurately obtained by using low level forcing. In ...
Development of a new adaptive harmonic balance method and its comparison
Sert, Onur; Ciğeroğlu, Ender; Department of Mechanical Engineering (2018)
Nonlinear systems are encountered in many areas of science. In order to study these systems on a theoretical level, many approaches regarding the solution of nonlinear equation systems have been developed. Harmonic Balance Method (HBM) is one of the most powerful and popular methods for solving nonlinear differential equations in frequency domain. The main idea of the method is representation of the time-periodic response and nonlinear internal forces in terms of Fourier series and balancing each harmonic t...
Utility analysis and computer simulation of RFID technologies in the supply chain applications of production systems
Bolatlı, Yurtseven; Eren, Pekin Erhan; Department of Information Systems (2009)
In this thesis, the feasibility of deploying RFID technologies in the case of “lowvolume high-value” products is considered by focusing on the production processes of a real company. First, the processes of the company are examined and associated problems are determined. Accordingly, a simulation of the current situation is constructed by using the discrete event simulation technique, in order to obtain an accurate model. In addition to modeling the current situation, this simulation model provides a flexib...
Localization and Identification of structural nonlinearities using neural networks
Yumer, Mehmet Ersin; Koyuncu, Anıl; Ciğeroğlu, Ender; Özgüven, Hasan Nevzat (2013-02-14)
In this study, a new approach is proposed for identification of structural nonlinearities by employing neural networks. Linear finite element model of the system and frequency response functions measured at arbitrary locations of the system are used in this approach. Using the finite element model, a training data set is created, which appropriately spans the possible nonlinear configurations space of the system. A classification neural network trained on these data sets then localizes and determines the ty...
Citation Formats
G. Özdoğan, “System identification and modeling of gyro-stabilized IR/EO gimbal system in frequency domain /,” M.S. - Master of Science, Middle East Technical University, 2014.