FBE- Makine Mühendisliği Lisansüstü Programı
Bu topluluk için Kalıcı Uri
Makina Mühendisliği Ana Bilim Dalı altında bir lisansüstü programı olup, sadece doktora düzeyinde eğitim vermektedir.
Gözat
Yayın Türü "Doctoral Thesis" ile FBE- Makine Mühendisliği Lisansüstü Programı'a göz atma
Sayfa başına sonuç
Sıralama Seçenekleri
-
ÖgeHigh precision motion control of mechatronic systems in presence of general uncertainties: Application with a heavy-duty parallel robot(Lisansüstü Eğitim Enstitüsü, 2022) Sancak, Kamil Vedat ; Bayraktaroğlu, Zeki Yağız ; 723041 ; Makine MühendisliğiThis thesis study is focused on precise control of heavy duty 6 DoF 5.500 kg payload Stewart_Gough platform which is designed and manifactured at Altınay company. Experimental work aiming to identify frictions in linear actuators of Stewart_Gough platform in order to improve tracking accuracy performances brought out significant amount of nonlinear friction. The parallel mechanism consists of six linear actuators with identical kinematic chains, coupling the moving upper and the fixed lower platforms through universal joints. The linear module actuaters of SGP contain a ball-screw mechanism mounted to frameless AC servo motors which are equipped with failsafe electromagnetic brakes and high resolution absolute encoders. Thes linear modules are subjected to gravitational forces that increase the effect and importance of elastic deformations in ball screw mechanisms. An inverse dynamical model derived using the Newton-Euler approach for similar Stewart_Gough platforms includes the dynamics of the linear modules. Since the rotor inertia of frameless AC servo motors can not be neglected due to their magnitudes linear module dynamics is included to the dynamic model of SGP. The mathematical model determines the driving forces acting on the legs according to the dynamic formulation. The LuGre and GMS (Generalized Maxwell Slip) dynamic friction models proposed in related literature are used to calculate friction forces of thelinear model actuators. Using experimental data and dynamical model of GSP, friction model parameters are identified. The system performance is experimentally evaluated as well by comparising of two different dynamic friction models. The identified models offer the possibility of further advanced studies of the platform structure in order to evaluate dynamic behaviors and designing controllers for high tracking accuracy Model-based control and non-model-based control methods are applied with the assistance of Luenberger-like observer and extended state observer (ESO). The Nonlinear PD and nonlinear computed torque control methods enabled to have precise position tracking of 6 DoF SGP.
-
ÖgeInvestigation of fabrication optimization and physical and mechanical properties of metallic syntactic foams manufactured by cold chamber die casting(Graduate School, 2022-01-07) Bolat, Çağın ; Gökşenli, Ali ; 503152030 ; Mechanical EngineeringIn recent years, metallic foams (MFs) have become considerably attractive for their unique features such as low density, high porosity, perfect energy absorption ability, good ductility, damping isolation, and sound isolation. From automotive and aviation to aerospace and defense, many different sectors can be thought of as target applications areas if the great potential of these advanced engineering materials is taken into the account. Considering the increasing competitiveness and worries on the environment, MFs can be perfect alternative materials for future projects. Metal matrix syntactic foams (MMSFs) are a subgroup of the closed-cell MFs. Also, they can be interpreted as particle reinforced composites since MMSFs compose of two main phases: a metallic matrix and cellular/porous/hollow ceramic reinforcement particles. Owing to their synergetic properties that reflect both MFs and particle reinforced composites, MMSFs have begun to replace standard foams and composites in real applications. The most important property of MMSFs is to provide high strength and energy absorption capability with little weight increment. This thesis is divided into six different sections and it is edited by obeying the process flow sequence. Initially, a detailed literature survey and technical background for the research thesis will be shared in the first chapter. The second, third, and fourth chapters are a copy of published articles. All experimental details and findings will also be given in these chapters. The fifth chapter is another section that reflects additional findings apart from the published papers. In the last section, all results and findings will be collected and shared in the light of experimental results and probable future works. In the second chapter, casting optimization studies were carried out by using three different expanded glass sizes.