Mekatronik Mühendisliği Bölümü Yayın Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12416/255
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Conference Object Citation Count: Bingöl, Hilal; Soysal, Gökhan; Schmidt, Klaus Werner. Controller Design for CACC with Time-varying Communication Delays, 31st IEEE Conference on Signal Processing and Communications Applications, SIU 2023, 31st IEEE Conference on Signal Processing and Communications Applications, SIU 2023, Istanbul, 5 July 2023through 8 July 2023.Controller Design for CACC with Time-varying Communication Delays(2023) Bingöl, Hilal; Soysal, Gökhan; Schmidt, Klaus Werner; 218795Cooperative 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∞ 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 timevarying communication and actuator delays, we develop the first controller design method for L∞-string stability, combining the Lyapunov-Krasovskii method and our custom bisection algorithm. Simulation experiments demonstrate the effectiveness of our method.Conference Object Citation Count: Gündoğan, Boran; Ergezer, Halit (2023). Comprehensive Comparison of Various Machine Learning Algorithms for RF Fingerprints Classification. 2023 Innovations in Intelligent Systems and Applications Conference, ASYU 2023, 2023 Innovations in Intelligent Systems and Applications Conference, ASYU 2023, Sivas, 11 October 2023through 13 October 2023.Comprehensive Comparison of Various Machine Learning Algorithms for RF Fingerprints Classification(2023) Gündoğan, Boran; Ergezer, Halit; 293396In 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.Article Citation Count: Bingol, Hilal; Schmidt, Klaus W. (2022). "String Stability Under Actuator Saturation on Straight Level Roads: Sufficient Conditions and Optimal Trajectory Generation", IEEE Transactions on Intelligent Transportation Systems, Vol.23, No.12, pp. 24588-24598.String Stability Under Actuator Saturation on Straight Level Roads: Sufficient Conditions and Optimal Trajectory Generation(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.Article Citation Count: Bingöl, Hilal; Çankaya, Erkam; Schmıdt, Klaus W. (2016). "Eyleyici doyumu altında dizi kararlı kooperatif otomatik seyir kontrolü", Pamukkale Üniversitesi Mühendislik Bilimleri Dergisi, Vol.22, No.8, pp.636-642.Eyleyici doyumu altında dizi kararlı kooperatif otomatik seyir kontrolü(2016) Bingöl, Hilal; Çankaya, Erkam; Schmıdt, Klaus Werner; 218795Kooperatif otomatik seyir kontrolü (CACC), araçtan araca haberleşme yöntemiyle veri iletilmesini ve uzaklık ölçümlerine göre yoğun trafikte güvenilir araç takibinin yapılmasını sağlar. Kullanılan CACC dizaynları dizi kararlılığının temel özelliklerini sorunsuz bir şekilde yerine getirirken doğrusal araç modelleri için sınırlıdır. Bu makalede ise, doğrusal olmayan araç modeli kullanıldığında ve lider araca uygulanan giriş sinyali doyuma uğramadığında dizi kararlılığının korunabildiği gösterilmiştir.Article Citation Count: Özgedik, Ali; Çoğun, C. (2014). "Farklı İşleme Derinliklerinde Uygulanan Titreşimlerin Elektro-Erozyon ile İşleme Performansına Etkisi", Makine Teknolojileri Elektronik Dergisi (elektronik), Vol.11, No.3Farklı İşleme Derinliklerinde Uygulanan Titreşimlerin Elektro-Erozyon ile İşleme Performansına Etkisi(2014) Özgedik, Ali; Çoğun, Can; 3837Bu çalışmada, Elektro-Erozyon ile İşleme (EEİ) tekniğinin performans çıktılarını iyileştirmek amacı ile işparçasına farklı frekansta titreşimlerin uygulandığı boşalım akımı ve işleme derinliği gibi farklı işleme koşullarında deneyler yapılmıştır. Deneylerde titreşimsiz koşullara göre elektrot aşınma hızı (EAH) ve bağıl aşınma (BA) değerlerinde belirgin azalma elde edilmiştir. Titreşimli deneylerde işparçası işleme hızı (İİH) ve ortalama yüzey pürüzlülüğü (Ra) değerlerinde EAH ve BA değerlerine göre daha küçük değişimler tespit edilmiştir.Conference Object Citation Count: Özkan, Ekin Cansu; Ergezer, Halit. "Kinematic Analysis and Position Control of Motor Grader Blade Mechanism for Automatic Levelling", International Conference on Control, Decision and Information Technologies (CoDIT), pp. 237-242, 202.Kinematic Analysis and Position Control of Motor Grader Blade Mechanism for Automatic Levelling(2022) Özkan, Ekin Cansu; Ergezer, Halit; 293396In this study, mechanism analysis, which is one of the necessary steps for automatic function control in construction machines, is emphasized. Motor grader construction machine has been chosen because there are a minimal number of studies in the literature. The blade mechanism of the motor grader has high degrees of freedom; it can perform various rotations and orientations in the XYZ axis. For this mechanism, which is very challenging to control and make kinematic analysis, functions that specify the motion behavior of the cutting-edge points are obtained using the polynomial surface fitting method. PI controllers were created for the MIMO system to reduce the existing steady-state error. Tests were performed for various scenarios on the actual machine, and the results were compared.Conference Object Citation Count: Erdem, Oğuz; Çoğun, Can; Uslan, İbrahim. "Investigation of Electrical Discharge Drilling (EDD) Performance of Ti-6Al4V Super Alloy", 1. International Symposium on Light Alloys and Composite Materials (ISLAC’18), March 22-24, 2018.Investigation of Electrical Discharge Drilling (EDD) Performance of Ti-6Al4V Super Alloy(2018) Erdem, Oğuz; Çoğun, Can; Uslan, İbrahim; 3837Ti-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 Citation Count: Bingöl, Hilal...et al. "Image-Based Remote Control Using FPGA", 7th Enginnering and Technology Symposium, 2014.Image-Based Remote Control Using FPGA(2014) Bingöl, Hilal; Kısa Işık, Gizay; Başayar, Tuğba; Genç, Fatih; Yengel, Emre; 218795Article Citation Count: Ayhan, Emre; Yurdakul, Mustafa; Çoğun, Can. (2021). "Elektrokimyasal Jet İşleme (EJİ) Parametrelerinin İşlenen Kanal Geometrilerine Etkisi", Gazi Mühendislik Bilimleri Dergisi, Vol.7, No.3, pp.213-221.Elektrokimyasal Jet İşleme (EJİ) Parametrelerinin İşlenen Kanal Geometrilerine Etkisi(2021) Ayhan, Emre; Yurdakul, Mustafa; Çoğun, Can; 3837Bu çalışmada alışılmamış imal usullerinden elektrokimyasal jet işleme yöntemi (EJİ) kullanılarak YHÇ 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.Article Citation Count: Gülcan, Orhan;...et.al. (2015). "Elektro Erozyon İle İşlemede Cu-Cr T/M Elektrot Kullanımının İşleme Performansına Etkisi", Gazi Üniversitesi Mühendislik Mimarlık Fakültesi Dergisi, Vol.30, No.3, pp.381-394.Elektro Erozyon İle İşlemede Cu-Cr T/M Elektrot Kullanımının İşleme Performansına Etkisi(2015) Gülcan, Orhan; Uslan, İbrahim; Usta, Yusuf; Çoğun, Can; 3837Bu çalışmada, Cu-Cr toz metal (T/M) elektrot kullanımının elektro erozyon ile işleme (EEİ) performans çıktılarından işparçası işleme hızı (İİH), elektrot aşınma hızı (EAH), işlenmiş yüzeyin ortalama ve azami yüzey pürüzlülükleri (Ra ve Rz) ve işparçası yüzey katman kalınlıklarına etkileri deneysel olarak incelenmiştir. Farklı toz karıştırma oranları, sıkıştırma basınçları ve sinterleme sıcaklıklarında elde edilen Cu-Cr T/M elektrotlar SAE 1040 çeliğinin işlenmesinde kullanılmıştır. Analizler, elektrot malzemesinin işparçası yüzeyinde katman halinde alaşımlandığını ve karıştırma oranı, sıkıştırma basıncı ve sinterleme sıcaklığının EEİ performans çıktılarını etkilediğini göstermiştir.Conference Object Citation Count: Çoğun, Can; Şimşek, Ülke. "Elektrolitik ve alaşım bakır elektrotların elektro-erozyon ile işleme performansına etkisi", 16th Int Conf on Machine Design and Production, İzmir TURKEY, 2014.Elektrolitik ve alaşım bakır elektrotların elektro-erozyon ile işleme performansına etkisi(2014) Çoğun, Can; Şimşek, Ülke; 3837Elektro 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 Citation Count: Oğuz, Erdem...et al. "Elektro Erozyon İle İşlemede Döner Elektrot İle Delik Delmede Dielektrik Sıvısına Karıştırılan Tozların Ve Isıtmanın İşleme Performansına Etkisi," Makine İmalat Teknolojileri Kongresi , Vol.2, pp.212-221, 2013.Elektro Erozyon İle İşlemede Döner Elektrot İle Delik Delmede Dielektrik Sıvısına Karıştırılan Tozların Ve Isıtmanın İşleme Performansına Etkisi(2013) Oğuz, Erdem; Çoğun, Can; Uslan, İbrahim; Urtekin, Levent; Özerkan, Hacı Bekir; 3837Conference Object Citation Count: Gülcan, Orhan...et al. "Electro discharge machining performance of chromium copper powder metal electrodes", 7th. International Powder Metallurgy ConferenceAt: Ankara, 2014.Electro discharge machining performance of chromium copper powder metal electrodes(2014) Gülcan, Orhan; Uslan, İbrahim; Usta, Yusuf; Çoğun, Can; 3837In 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 Citation Count: Yalçın, F.; Ozturk, A.; Gulgec, M. ko“Effect of the Material Properties on the Yielding of the Two-Layered Composite Cylinder with Free Ends”, 13th International Conference Computational and Mathematical Methods in Science and Engineering (CMMSE-2013), June 24- 27 2013, Almería, Spain.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 Citation Count: Erdem, Oğuz; Çoğun, Can; Uslan, İ. (2019). "Effect of Machining on Workpiece Surface Characteristics in Electric Discharge Drilling (EDD)", International journal of advances in engineering and pure sciences (Online), Vol.31, No.1, pp.11-16.Effect of Machining on Workpiece Surface Characteristics in Electric Discharge Drilling (EDD)(2019) Erdem, Oğuz; Çoğun, Can; Uslan, İbrahim; 3837In electric discharge drilling (EDD), rapid local heating and cooling of the workpiece surface by means of electric discharges results insurface layers (recast, heat affected and base material). In this study, the main workpiece surface texture measures, namely the recast layerthickness (RLT) and average surface roughness (Ra) characteristics were investigated for varying machining parameters (discharge currentand pulse on time). The conducted experiments revealed the strong dependence of surface characteristics on machining parameters.Conference Object Citation Count: Gülcan, Orhan;...et.al. (2016). "EDM Performance of B4C Cu Based Sintered Tool Electrodes", Journal of Material Science and Technology, Vol.24, No.1, pp.3-10.EDM Performance of B4C Cu Based Sintered Tool Electrodes(2016) Gülcan, Orhan; Uslan, İbrahim; Usta, Yusuf; Çoğun, Can; 3837Article Citation Count: Alsaka, Dina Yaqoob;...et.al. (2022). "Dynamic flat-topped laser beam shaping method using mixed region amplitude freedom algorithm", Applied Physics B: Lasers and Optics, Vol.128, No.8.Dynamic flat-topped laser beam shaping method using mixed region amplitude freedom algorithm(2022) Alsaka, Dina Yaqoob; Arpali, Çağlar; Arpali, Serap Altay; Altemimi, Mohammed Fawzi; 20809A 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 Citation Count: Kart, Bora Eser; Schmidt, Klaus. "Computation of Reduced Diagnosers for the Fault Diagnosis of Discrete Event Systems", Engineering and Technology Symposium, 2014.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 Count: Erdoğan, S.; Bektaş, a.; Ergezer, H. (2022). "Development of air-to-ground engagement analysis model of fighter aircrafts", Journal of the Faculty of Engineering and Architecture of Gazi University, Vol.37, No.4, pp.2225-2239.Development of air-to-ground engagement analysis model of fighter aircrafts(2022) Erdoğan, Sinem; Bektaş, Almila; Ergezer, Halit; 293396In 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 Count: Özerkan, Hacı Bekir; Çoğun, Can. (2022). "Design and implementation of an electrode feed rate control system in the electrochemical drilling process", Journal of the Brazilian Society of Mechanical Sciences and Engineering, Vol.44, No.9.Design and implementation of an electrode feed rate control system in the electrochemical drilling process(2022) Özerkan, Hacı Bekir; Çoğun, Can; 3837The 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.
