Mekatronik Mühendisliği Bölümü Yayın Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12416/255
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Conference Object Citation - WoS: 0Citation - Scopus: 0Controller Design for CACC with Time-varying Communication Delays(Ieee, 2023) Bingol, Hilal; Bingöl, Hilal; Soysal, Gokhan; Schmidt, Klaus Werner; 218795; Mekatronik MühendisliğiCooperative Adaptive Cruise Control (CACC) aims at the safe and comfortable travel of vehicles at short distances in the form of platoons. Hereby, it is generally desired to attenuate disturbances along vehicles in a platoon, which is captured by different string stability conditions. In this paper, we focus on L-infinity string stability. This condition ensures reducing the magnitude of the acceleration signal along the platoon, which helps to avoid actuator saturation and increases driving comfort. Since the performance of CACC is adversely affected by time-varying communication and actuator delays, we develop the first controller design method for L-infinity-string stability, combining the Lyapunov-Krasovskii method and our custom bisection algorithm. Simulation experiments demonstrate the effectiveness of our method.Conference Object Citation - Scopus: 0Comprehensive Comparison of Various Machine Learning Algorithms for RF Fingerprints Classification(Institute of Electrical and Electronics Engineers Inc., 2023) Gundogan, B.; Ergezer, Halit; Ergezer, H.; 293396; Mekatronik MühendisliğiIn these days, the use of drones has become quite common. Remote controls can do the control of these drones with RF signals. It is important to prevent security vulnerabilities caused by using drones in our daily lives. A complex dataset was created by extracting the characteristics of the RF signals and preprocessing them. To solve this complex data set and problem, the application of models including Support Vector Machine (SVM), Random Forest, Decision Tree, Gradient Boosting, XGBoost and Neural Network (NN) models, including various ML models and comparison of optimization studies of these applied models are examined in this article. In addition, a wide range of studies was carried out to compare ML models, including comparison metrics such as Accuracy, Precision, Recall, Mean Squared Error (MSE), F1 Score, $R^{2}$ and Training Time. In line with these results, the highest score was obtained in the $\mathrm{R}^{2}$ comparison metric (97%) in the Neural Network (NN). Compared to the others, the results of Neural Network (NN) were more successful, but the Training Time (245 sec) in the Neural Network (NN) method is by far more than the other ML methods, which shows us that the NN method requires a very high computing process. As a result of the comparison, another outstanding Ensemble-based ML method is Decision Tree. This is because besides the very low Training Time $(5\sec)$, it has managed to be the 2nd ML algorithm with the highest $\mathrm{R}^{2}$ score (96%). Apart from these, among other ML methods, SVM performed slightly less well $(\mathrm{R}^{2}$ 91%) in solving this complex problem. The advanced Gradient Method (95%) and XGBoost (96%), which also have the Ensemble structure, showed a head-to-head performance regarding $\mathrm{R}^{2}$ scores. However, XGBoost (30 sec) has a very short Training Time compared to Gradient Boosting (180 sec). As a result, the approach of each ML method to solving the complex problem differed from each other, and the success rates and Training Time also differed equally. The most important work to be done here is to choose which ML method you want to achieve according to the limited system in hand and the performance-accuracy dilemma. © 2023 IEEE.Article Citation - WoS: 2Citation - Scopus: 2String Stability Under Actuator Saturation on Straight Level Roads: Sufficient Conditions and Optimal Trajectory Generation(Ieee-inst Electrical Electronics Engineers inc, 2022) Bingol, Hilal; Schmidt, Klaus Werner; 218795The heterogeneity of vehicles is an important factor when realizing cooperative adaptive cruise control (CACC) in practice. Specifically, it has to be considered that platoons generally consist of vehicles with both different dynamic properties and actuator limits on the engine and braking force, which is expected to have a negative impact on important properties such as string stability. Accordingly, the subject of this paper is the preservation of string stability for CACC in heterogeneous vehicle strings with potential actuator saturation. To this end, the paper formulates a velocity-dependent force bound that enables the derivation of sufficient conditions for preserving string stability during velocity changes of heterogeneous platoons. These conditions are then used for the analytical computation of trajectories for time-optimal velocity changes. The formal results of the paper are supported by an illustrative simulation study.Conference Object Investigation of Electrical Discharge Drilling (EDD) Performance of Ti-6Al4V Super Alloy(2018) Çoğun, Can; Çoğun, Can; Uslan, İbrahim; 3837; Mekatronik MühendisliğiTi-6Al-4V super alloy (Ti64) is widely used in many engineering applications such as automotive, aviation and aerospace owing to its low density and high strength properties. Because of its high toughness and high melting temperature, Ti64 is regarded as a difficult-to-machine material in conventional machining. Furthermore, it is also difficult to machine in Electrical Discharge Drilling (EDD) due to its high electrical resistance and low thermal conductivity. The EDD performance is quantified by material removal rate (MRR), electrode wear rate (EWR), relative wear (RW), surface roughness (SR) and surface characteristic of drilled workpiece. The main goal of this study is to experimentally investigate the performance outputs (MRR, EWR, RW and SR) of Ti64 super alloy in EDD operation.Conference Object Image-Based Remote Control Using FPGA(2014) Bingöl, Hilal; Yengel, Emre; Başayar, Tuğba; Genç, Fatih; Yengel, Emre; 218795; Mekatronik Mühendisliği; Elektrik-Elektronik MühendisliğiArticle Elektrokimyasal Jet İşleme (EJİ) Parametrelerinin İşlenen Kanal Geometrilerine Etkisi(2021) Ayhan, Emre; Çoğun, Can; Yurdakul, Mustafa; Çoğun, Can; 3837; Mekatronik MühendisliğiBu çalışmada alışılmamış imal usullerinden elektrokimyasal jet işleme yöntemi (EJİ) kullanılarak HSS malzeme üzerine kanallar oluşturularak, işleme parametrelerinin kanal kesit geometrisine etkileri incelenmiştir. Çalışmada, işleme parametreleri olarak takım ilerleme hızı, işleme gerilimi, elektrolit sıvı basıncı ve elektrolit tuz derişimi ele alınmıştır. Her deneye ait kanal kesit geometrileri için profil tamlık değerleri, ortalama kanal derinliği ve genel uyum değerleri hesaplanmıştır. Hesaplanan genel uyum değerlerinde en iyi sonuçların işleme geriliminin 20 V olduğu deneylerde elde edildiği görülmüştür. Takım ilerleme hızının 0,5 mm/dak olduğu deneylerde genel uyum değerlerinin daha yüksek olduğu görülmüştür.Conference Object Elektrolitik ve alaşım bakır elektrotların elektro-erozyon ile işleme performansına etkisi(2014) Çoğun, Can; Şimşek, Ülke; 3837; Mekatronik MühendisliğiElektro erozyon ile işlemenin (EEİ) en önemli maliyet unsuru elektrotun üretilmesidir. EEİ’de en yaygın kullanılan elektrot malzemeleri bakır ve alaşımlarıdır. Maliyeti arttırmadan EEİ yapmanın yolu, hammadde maliyeti düşük, işlemesi kolay ve elektriksel aşınma direnci yüksek bakır alaşımlarını tespit etmektir. Bu çalışmada, EEİ’de elektrot olarak kullanılan elektrolitik bakır, CuCr1Zr ve CuCo2Be bakır alaşımları için işleme hızı, elektrot aşınma hızı, bağıl aşınma ve işparçası yüzey pürüzlülüğü gibi performans çıktıları deneysel olarak incelenmiştir. Ayrıca, CuCr1Zr alaşımına uygulanan yaşlandırma işlemi sonrası artan elektriksel iletkenliğin EEİ performans çıktılarına etkileri incelenmiştir. Performans çıktılarının alaşım türünden ve uygulanan yaşlandırma işleminden etkilendiği görülmüştür.Conference Object Elektro Erozyon İle İşlemede Döner Elektrot İle Delik Delmede Dielektrik Sıvısına Karıştırılan Tozların Ve Isıtmanın İşleme Performansına Etkisi(2013) Çoğun, Can; Çoğun, Can; Uslan, İbrahim; Urtekin, Levent; Özerkan, Hacı Bekir; 3837; Mekatronik MühendisliğiConference Object Electro discharge machining performance of chromium copper powder metal electrodes(2014) Çoğun, Can; Uslan, İbrahim; Usta, Yusuf; Çoğun, Can; 3837; Mekatronik MühendisliğiIn electro discharge machining used frequently in tool production, copper and graphite is commonly used as electrode material. The reason of this is high melting temperatures and excellent electrical and thermal conductivity of these materials. But, the low wear resistance of these materials makes it necessary to investigate different materials that have more wear resistance. Up to now, apart from copper, materials like brass, chromium, tungsten, steel, titanium have been used in electrode production. Apart from different materials, different production techniques have been investigated to increase production time. Powder metallurgy is one of these techniques. Electrode production with powder metallurgy becomes more advantageous than other production techniques due to the possibility of different powder combinations and controlling of thermal, electrical, mechanical and micro structure properties of produced electrodes with pressing pressure and sintering temperature. In the present study, chromium-copper composite electrodes produced with powder metallurgy will be used for electro discharge machining of SAE 1040 steel and material removal rate, electrode wear rate and surface roughness values will be compared with values from machining with electrolytic copper.Conference Object Effect of the Material Properties on the Yielding of the Two-Layered Composite Cylinder with Free Ends(2013) Yalçın, F.; Öztürk, A.; Gülgeç, M.; 4168Article Effect of Machining on Workpiece Surface Characteristics in Electric Discharge Drilling (EDD)(2019) Çoğun, Can; Erdem, Oguz; Çoğun, Can; Uslan, İbrahim; 3837; Mekatronik MühendisliğiElektro erozyon ile delik delmede (EEDD), işparçası yüzeyinin elektriksel boşalmalar yoluyla hızlı bir şekilde bölgesel olarak ısıtılması ve soğutulması, yüzey katmanlarına (tekrardan katılaşmış, ısıl etkilenmiş ve ana malzeme) neden olur. Bu çalışmada, ana işparçası yüzey dokusu, yani tekrardan katılaşmış katman kalınlığı (RLT) ve ortalama yüzey pürüzlülüğü (Ra) özellikleri, farklı işleme parametreleri için (boşalım akımı ve vurum süresi) araştırılmıştır. Yapılan deneyler, yüzey özelliklerinin işleme parametrelerine kuvvetle bağımlılığını ortaya koymuştur.Conference Object EDM Performance of B4C Cu Based Sintered Tool Electrodes(2016) Çoğun, Can; Uslan, İbrahim; Usta, Yusuf; Çoğun, Can; 3837; Mekatronik MühendisliğiArticle Citation - WoS: 5Citation - Scopus: 6Dynamic flat-topped laser beam shaping method using mixed region amplitude freedom algorithm(Springer Heidelberg, 2022) Alsaka, Dina Yaqoob; Arpali, Çağlar; Arpali, Caglar; Arpali, Serap Altay; Altemimi, Mohammed Fawzi; 20809; Mekatronik MühendisliğiA dynamic beam shaping method is proposed for the generation of flat-top beams (FTBs) in the far field. Using the mixed-region amplitude freedom algorithm, this new method is used to design the required phase distribution encoded on a spatial light modulator for the generation of FTB profiles. The characteristics of these new beam shaping methods are used as beam parameters, such as the laser beam size, the beam intensity of square FTBs, and the root-mean-square error (RMSE). Using our proposed method, the theoretical performance of beam intensity shaping is improved to an RMSE < 0.02 with a minimum number of iterations of phase reconstruction. Using the phase hologram of dynamic beam shaping, theoretical and experimental comparisons of edge steepness and plateau uniformity were established for the square FTBs of variable beam sizes. It is shown that the dynamic beam shaping of FTBs can produce high intensity uniformity in the plateau region with steep edges, which makes it an effective tool, especially for laser machining applications.Conference Object Computation of Reduced Diagnosers for the Fault Diagnosis of Discrete Event Systems(2014) Kart, Bora Eser; Schmidt, KlausMany complex systems in different areas such as manufacturing, telecommunications or transportation can be modeled as discrete event systems (DES). In this paper, we consider the fault diagnosis for DES which is concerned with detecting fault occurrences in a DES within a bounded number of event occurrences by a diagnoser automaton. Hereby, such diagnoser is able to observe a subset of the system events and the maximum required number of event occurrences until a fault detection is denoted as the worst case detection delay (WCDD). The main contribution of the paper is an approach for reducing the number of required observations for fault diagnosis without increasing the WCDD. As a result, it is possible to determine a diagnoser with a small size which is essential in practical applications. We first develop an algorithm for computing the WCDD and then adapt an approach for the reduction of the observable event set in order to obtain a reduced diagnoser. The application of our method to a communication system example demonstrates its practicability.Article Citation - WoS: 2Citation - Scopus: 2Development of air-to-ground engagement analysis model of fighter aircrafts(Gazi Univ, Fac Engineering Architecture, 2022) Erdogan, Sinem; Ergezer, Halit; Bektas, Almila; Ergezer, Halit; 293396; Mekatronik MühendisliğiIn operational analysis studies; it is possible to model and simulate at an engineering level, engagement level, task level and campaign forces level. In this study, modelling and simulation studies are performed in engagement-level allowing the analysis of air-to-ground engagement effectiveness of fighter aircraft according to the operational environment. The operating environment of the combat aircraft, which provides survivability analysis based on low visibility and electronic mixing capabilities, is created. The search radar and tracking radar models for ground-to-air threats have been designed in accordance with the engagement level. The dynamic model of the fighter aircraft and the ground-to-air missile have been modelled using pseudo 5 degree-of-freedom. Modelling has been carried out to allow the use of changes in the Radar Crosssectional Area (RCS), which is one of the most important factors affecting the survivability of the aircraft, with respect to azimuth and elevation angles. The Radio Frequency (RF) jamming capability of the fighter aircraft has also been modelled in accordance with the engagement level. The results of the generic scenarios for the analysis of the effect of these models' parameters on the survivability of fighter aircraft have been presented.Article Citation - WoS: 6Citation - Scopus: 6Design and implementation of an electrode feed rate control system in the electrochemical drilling process(Springer Heidelberg, 2022) Ozerkan, Haci Bekir; Çoğun, Can; Cogun, Can; 3837; Mekatronik MühendisliğiThe interelectrode gap distance control is essential for preventing short circuit and spark discharge occurrences in the machining gap and ensuring a constant distance between the tool electrode (shortly electrode) and the workpiece throughout the electrochemical drilling (ECD) process. In this study, a gap distance control system was designed and implemented in the constructed ECD machine tool. The gap distance control strategy was based on the machining current's discrete measurement (in microsecond intervals) and changing the gap distance according to a set current value by feeding the electrode towards the workpiece or retracting it during the ECD process. The small diameter deep hole ECD experiments were conducted using 0.5 mm diameter side insulated tubular rotational electrodes with through-hole electrolyte flushing to drill Hadfield and AISI 1040 steels. The experimental results demonstrated the success of the developed control system in ECD operations yielding uniform hole geometries and smooth hole surfaces. The use of the control system eliminated the undesirable formations of spark discharges and short circuit pulses.Article Çoklu ˙IHA Kullanımı ile Kabloya Asılı Yük Ta¸sınımı Transportation of Cable Suspended Slung Load System Using Multiple UAVs(2022) Ergezer, Halit; Leblebicioğlu, M. Kemal; Ergezer, Halit; 293396; Mekatronik MühendisliğiBu çalı¸smada, kablolar ile asılı esnemeyen bir yükün ortakla¸sa ta¸sınımı için kontrolcü tasarımı tanıtılmı¸stır. Yük, birden çok insansız hava aracına (˙IHA) yükün kablo ile baglanması ˘ ile ta¸sınmakta olup, istenen üç boyutlu rota üzerinde hareket etmesi saglanmaktadır. Sistemde yük lider olarak alınmaktadır. ˘ Hiyerar¸sik ve merkezcil bir yapıda kontrol edilmektedir. Ta¸sıma görevi, bir optimizasyon problemi olarak ele alınmı¸stır. Sistemi istenen rotada hareket ettirebilmek için bir otopilot algoritması tasarlanmı¸s olup PD yapıları kullanılarak olu¸sturulmu¸stur. Pozisyon kontrolcüsünün çıktısı kontrol atama matrisi tarafından ele alınmaktadır ve uygun kuvvet dagılımını sistemin istenen ˘ davranı¸slarına uygun olacak ¸sekilde türetmektedir. Kontrolcü performansları, takip edilmesi istenen bir rota üzerinde test edilmektedir.Article A comparison of iterative Fourier transform algorithms for image quality estimation(2018) Arpali, Çağlar; Arpali, Çağlar; Arpali, Serap Altay; 20809; Mekatronik MühendisliğiA comparison was established between two iterative Fourier transform algorithms (IFTAs), such as the original Gerchberg–Saxton (GS) and the mixed-region amplitude freedom (MRAF) algorithms, for the hologram reconstruction of different target images through the full reference image quality estimation (IQE) and pixel homogeneity in the Fourier plane presented theoretically and experimentally. The comparison was applied depending upon both algorithms based on a computer-generated hologram (CGH) implemented utilizing a reflective phase-modulated liquid-crystal spatial light modulator (LC-SLM) to obtain the digital kinoform holograms of the desired intensity distributions. These digital holograms were applied to reconstruct the intensity patterns for 852 nm, which represents a laser beam source. The theoretical and experimental results of the reconstructed patterns obtained using the MRAF algorithm were found to be smoother and better than the patterns obtained using the GS algorithm. Unmodulated light beam (dc term) is removed from the reconstructed patterns attributed to digital kinoform holograms of MRAF algorithm as an alternative to the theoretical and experimental results without using any additional optic equipment at the light path. Moreover, this paper discussed the full reference objective quality estimations, such as mean square error (MSE), peak signal-to-noise ratio (PSNR), structural content (SC), normalized absolute error (NAE), normalized cross correlation (NK), and homogeneity of pixels, through the contrast (Cont) and inverse difference moment (IDM) for numerical and experimental results. According to the two desired intensity distributions processed theoretically and experimentally, the results of MRAF algorithm were found to be in the highly accurate recovered phase, the quality of image was enhanced, and the dc term was decreased. Image quality estimation of full reference objective relay on the feedback algorithms experimental attestation has not been implemented yet.Article Citation - WoS: 2Citation - Scopus: 3Window length insensitive real-time EMG hand gesture classification using entropy calculated from globally parsed histograms(Sage Publications Ltd, 2023) Algüner, Ayber Eray; Alguner, Ayber Eray; Ergezer, Halit; Ergezer, Halit; 293396; Mekatronik MühendisliğiElectromyography (EMG) signal classification is vital to diagnose musculoskeletal abnormalities and control devices by motion intention detection. Machine learning assists both areas by classifying conditions or motion intentions. This paper proposes a novel window length insensitive EMG classification method utilizing the Entropy feature. The main goal of this study is to show that entropy can be used as the only feature for fast real-time classification of EMG signals of hand gestures. The main goal of this study is to show that entropy can be used as the only feature for fast real-time classification of EMG signals of hand gestures. Additionally, the entropy feature can classify feature vectors of different sliding window lengths without including them in the training data. Many kinds of entropy feature succeeded in electroencephalography (EEG) and electrocardiography (ECG) classification research. However, to the best of our knowledge, the Entropy Feature proposed by Shannon stays untested for EMG classification to this day. All the machine learning models are tested on datasets NinaPro DB5 and the newly collected SingleMyo. As an initial analysis to test the entropy feature, classic Machine Learning (ML) models are trained on the NinaPro DB5 dataset. This stage showed that except for the K Nearest Neighbor (kNN) with high inference time, Support Vector Machines (SVM) gave the best validation accuracy. Later, SVM models trained with feature vectors created by 1 s (200 samples) sliding windows are tested on feature vectors created by 250 ms (50 samples) to 1500 ms (300 samples) sliding windows. This experiment resulted in slight accuracy differences through changing window length, indicating that the Entropy feature is insensitive to this parameter. Lastly, Locally Parsed Histogram (LPH), typical in standard entropy functions, makes learning hard for ML methods. Globally Parsed Histogram (GPH) was proposed, and classification accuracy increased from 60.35% to 89.06% while window length insensitivity is preserved. This study shows that Shannon's entropy is a compelling feature with low window length sensitivity for EMG hand gesture classification. The effect of the GPH approach against an easy-to-make mistake LPH is shown. A real-time classification algorithm for the entropy features is tested on the newly created SingleMyo dataset.Article Citation - WoS: 3Citation - Scopus: 5Two Majority Voting Classifiers Applied to Heart Disease Prediction(Mdpi, 2023) Karadeniz, Talha; Maraş, Hadi Hakan; Karadeniz, Talha; Maras, Hadi Hakan; Tokdemir, Gül; Tokdemir, Gul; Ergezer, Halit; Ergezer, Halit; 34410; 293396; Bilgisayar Mühendisliği; Mekatronik Mühendisliği; Yazılım MühendisliğiTwo novel methods for heart disease prediction, which use the kurtosis of the features and the Maxwell-Boltzmann distribution, are presented. A Majority Voting approach is applied, and two base classifiers are derived through statistical weight calculation. First, exploitation of attribute kurtosis and attribute Kolmogorov-Smirnov test (KS test) result is done by plugging the base categorizer into a Bagging Classifier. Second, fitting Maxwell random variables to the components and summating KS statistics are used for weight assignment. We have compared state-of-the-art methods to the proposed classifiers and reported the results. According to the findings, our Gaussian distribution and kurtosis-based Majority Voting Bagging Classifier (GKMVB) and Maxwell Distribution-based Majority Voting Bagging Classifier (MKMVB) outperform SVM, ANN, and Naive Bayes algorithms. In this context, which also indicates, especially when we consider that the KS test and kurtosis hack is intuitive, that the proposed routine is promising. Following the state-of-the-art, the experiments were conducted on two well-known datasets of Heart Disease Prediction, namely Statlog, and Spectf. A comparison of Optimized Precision is made to prove the effectiveness of the methods: the newly proposed methods attained 85.6 and 81.0 for Statlog and Spectf, respectively (while the state of the heart attained 83.5 and 71.6, respectively). We claim that the Majority Voting family of classifiers is still open to new developments through appropriate weight assignment. This claim is obvious, especially when its simple structure is fused with the Ensemble Methods' generalization ability and success.
