Ahmet Kuzu

Automatic interlocking table generation from railway topology

In this paper, an algorithm for automatic interlocking table generation and its implementation is introduced. The specially developed software generates an interlocking table conforming to Turkish Railway regulations. Pseudo codes of the method and their descriptions are given. The method is demonstrated on a small station area, and sample outputs are presented.

Automated interlocking algorithm generation from interlocking tables for railway signalization systems

In this paper, an algorithm for automated interlocking generation and its implementation in Microsoft Visual Basic is introduced. The software developed generates an automaton model and necessary pseudo code to realize a given railway interlocking table. The method is demonstrated on the interlocking table of a small station area, and sample outputs are presented.

Multipurpose wireless sensor network platform for research and training in data fusion, and multi-feature target tracking

This paper introduces a multipurpose wireless sensor network (WSN) platform for education and research. The WSN platform is designed with state-of-the-art multiple sensor modules with high processing capability and can support a variety of research and education projects in sensor/data fusion and target tracking algorithms. The modules comprise of odor sensors in combination with different motion, sound, and temperature sensors to address multi-level research and education projects in plume source localization (for odor and/or temperature), and non-odor based target detection and tracking, as well as efficient communication strategies in WSNs. A novelty of the platform is that it offers a combination of odor, and non-odor based sensors, which facilitate research in mobile odor source tracking. The platform has been established as part of a MS thesis project, and is currently under development with the addition of odor sensors to allow for an increased variety of graduate studies as thesis projects and in sensor fusion courses.

Control and measurement delay compensation in bilateral position control

The main aim of this study is the improvement of the previously presented disturbance observer based bilateral control approaches of the authors with a delay regulator and a model tracking control (MTC) that runs on the slave side. These improvements eliminate the problems related to variable time delay inherent to such systems and model mismatch, respectively, and, hence, addressing the control and measurement delay problems in bilateral control applications. The performance is evaluated experimentally on a single-link arm controlled over the internet. The results demonstrate a significant improvement over the previously presented results obtained under load uncertainties and randomly varying network delays both in the control and feedback loop.

Fast locking of PLLs using sliding mode control

In this study, a chattering free sliding mode controller (SMC) is designed for the control of PLL based frequency synthesizers. Due to fast locking requirement of PLL based frequency synthesizers in frequency hopping spread spectrum communication and radar applications, a sliding mode control approach is demonstrated to be more suitable with its high gain property, over classical control methods. The obtained simulation results are compared with those of a PID controller, and traditional controller design and it has been concluded that the settling time of the frequency synthesizer can be improved using the developed SMC.

WPT based compression for bilateral control

This paper introduces a codec scheme for compressing control and feedback signals especially for bilateral control systems. The method uses a low pass filter and Wavelet Packet Transform (WPT) for coding and Inverse Wavelet Packet Transform (IWPT) for decoding. Data compression is handled in low pass filter output by reducing sampling rate; and in high pass filter output by reducing wavelet outputs. Codec works on both data paths, which flows between a master system and a slave system over a networked control architecture. With the proposed scheme, a greater percent of the compressed data can be recovered using the same compression rate. It is confirmed that the controller using compressors and decompressors performs similarly as the uncompressed one while enabling transmission of much less data over network. The viability of the proposed scheme is proven by experiments on a single-DOF motion control system controlled over network. Proposed method is also compared with a benchmark method which uses DFT for compression.

Performance comparison of compression techniques used in bilateral control

This paper analyzes two recently proposed compression decompression algorithms used in networked motion control systems. The algorithms contain discrete cosine transform (DCT) based and discrete fourier transform (DFT) based codecs for the realization of signal transmission over network. The backgrounds of the algorithms are presented along with a discussion on the advantages and disadvantages. Comparison of the performances of both algorithms are presented based on three different evaluation criteria including compression ratio, buffer size and power error. The differences between the algorithms are validated with results obtained from a series of experiments. Theoretical details regarding the differences between the results obtained from experiments are provided to present a complete analysis between two approaches.

Calibration and test of DIFAR sonobuoys

In this paper, a method for calibrating and testing DIFAR sonobuoy multiplexer without sea or water is proposed. For this purpose; the architecture of DIFAR sonobuoy is introduced, calibration factors are expressed, calibration and test environment in terms of hardware and software are described, calibration and test procedure is explained, and finally, advantages and disadvantages of the proposed calibration and test method is discussed.

Comparative evaluation of two chattering-free sliding mode controllers for the control of MEM optical switches

This study presents the design and simulation based comparison of two chattering-free SMC approaches for the position control of MEM microactuators The obtained results are benchmarked against a previously published chattering free SMC study, also for the control of micromirrors. Although crucial for increased reliability in MEM actuators, chattering free SM based controllers are rare in this area. The proposed chattering free SMCs proposed and tested in this study .provide a faster settling time as well as increased reliability, which are both critical performance criteria for the control of micromirrors.

Comparative Analysis of a Selected DCT-Based Compression Scheme for Haptic Data Transmission

In this study, a novel compression and decompression algorithm, namely the selected discrete cosine transform (DCT), is presented for implementation in networked motion control systems. The proposed method relies on the utilization of a selection algorithm based on bubble sorting to choose the highest power coefficients of the signal obtained by using DCT. In order to better illustrate the effectiveness of the proposed method, comparisons are made with the methods existing in the literature. To this aim, the basics of the compression schemes used in the comparison, namely, the DCT, discrete Fourier transform, and wavelet packet transform, are also briefly discussed followed by the derivation of the proposed method. The algorithmic bases of all four schemes are given to provide further reference for practical applications. The proposed method is tested on an experimental platform consisting of a single-single-degree-of-freedom master and slave systems, and the results are comparatively analyzed based on relevant performance evaluation metrics. The obtained results demonstrate the improvement achieved by the proposed compression scheme over the existing compression methods used in network-based motion control applications, hence proving the feasibility of the approach in teleoperation systems.