Doğrusal mantık uslamlamasının sürekli kısıtlar varlığında kullanımı ile dinamik robotlarda otonom davranış progralaması

TÜBİTAK EEEAG Proje01.03.201

Karmaşık mekanik sistemlerin modellenmesi ve denetlenmesi

TÜBİTAK TBAG Proje01.05.1994Bu projede katı ve esnek kısımları olan karmaşık mekanik sistemlerin modellenmesi ve denetlenmesi problemleri incelenmiştir. Araştırmaya temel olması açısından bir ucun-dan katı bir yapıya sıkı bağlı, diğer ucu serbest bir esnek çubuk ele alınmıştır. Basit-lik açısından bu sistemin düzlemde döndüğü ve katı cismin ağırlık merkezinin zamanla değişmediği varsayılmıştır. Bu sistem için ele alman denetleme problemleri kararlılık, yönlendirme, sabit açısal hız izleme ve bozucu bastırma problemleridir. Bu problemleri çözmek için katı cisme uygun bir denetleme momenti, esnek çubuğun serbest ucuna da uygun denetleme kuvveti ve momenti uygulanabildiği varsayılmıştır. Katı cismin açısal hızının ve esnek çubuğun serbest ucunun hızının ölçülebildiği varsayılarak bu büyüklükleri giriş olarak kabul edip uygun denetleme momentleri ve kuvvetini üreten ve yukarda anılan denetleme problemlerini çözen denetleyiciler tasarlanmıştır

Robust LQ Control for Harmonic Reference/Disturbance Signals

Linear Quadratic (LQ) controller design is considered for continuous-time systems with harmonic signals of known frequencies and it is shown that the design is reducible to an interpolation problem. All LQ optimal loops are parametrized by a particular solution of this interpolation problem and a (free) stable/proper transfer function. The appropriate choice of this free parameter for optimal stability robustness is formulated as a multiobjective design problem and reduced to a Nevanlinna-Pick interpolation problem with some interpolation points on the boundary of the stability domain. Using a related result from the literature, it is finally shown that, if there is sufficient penalization on the power of the control input, the level of optimum stability robustness achievable with LQ optimal controllers is the same as the level of optimum stability robustness achievable by arbitrary stabilizing controllers

Adaptif Kontrol Yöntemiyle Bacaklı Robotlarda Yüksek Performanslı Koşma Davranışı Geliştirilmesi

TÜBİTAK EEEAG Proje01.03.2017Model tabanlı ve dinamik kararlılıga ihtiyaç duyan bacaklı yürüme ve kosma davranıslarınınfiziksel robotlarda gerçeklenmesi statik kararlılık özelligine sahip davranıslara göre oldukçazordur. Bu zorlugun temel nedenlerinden birisi ilgili dinamiklerin sistem parametrelerinehassas bagımlılık göstermesidir. Bu parametrelerin hassas bir sekilde ölçülememesi vemalzeme yorulması veya asırı kullanım nedeniyle zamanla degisim göstermesi de problemidaha da kötü bir hale getirmektedir.Bu çalısmanın temel amacı tek bacaklı zıplayan bir robot platformu için çevrimiçi parametrekestirimi yaparak model-tabanlı yüksek performanslı kosu davranısını destekleyen bir adaptifkontrolcü yapısı ortaya koymaktır. Aslında daha önceki çalısmalarımızda benzetimortamlarında basit Yaylı Ters Sarkaç (YTS) modeli için çevrimiçi parametre kestirimi yaparakkalıcı hal takip hatalarını gideren bir adaptif kontrolcü gelistirilmistir. Bu noktada amacımızöncelikle bu adaptif kontrolcü yapısının Tork-Tahrikli ve Kayıplı Yaylı Ters Sarkaç (TTK-YTS)modeline uyarlanmasını saglamak ve ardından gelistirilen adaptif kontrolcü yapısının testedilebilecegi tek bacaklı zıplayan robot platformunu ortaya koymaktır.Bu amaçla öncelikle daha önce laboratuvarımızda gelistirmis oldugumuz tek bacaklı zıplayanrobot platformu üzerinde yüksek performanslı kosma davranısını destekleyecek mekanik veelektronik revizyonlar yapılmıstır. Daha sonra öncelikle TTK-YTS modeli için gelistirilen biryakınsamalı analitik çözümün gerçek robot verileri üzerinde dogrulaması yapılmıstır. Buamaçla robotun tek adımlık testleri üzerinden veri toplanmıs, ardından bu matematiksel modeliçin parametrik sistem tanılaması yapılarak robot parametrelerinin kestirimi saglanmıstır. Bumodelin robot gezingelerini ne kadar iyi tahmin ettigi fiziksel testler aracılıgıyla detaylıcagösterilmistir.Projenin son asamasında, fiziksel olarak dogrulanmıs yakınsamalı analitik çözüm kullanılarakrobotun istenen hız ve yükseklikte kosmasını saglayacak model-tabanlı tam hedef kontrolcüyapısı gelistirilmistir. Bu kontrolcünün robot üzerindeki performansı farklı deneylerleincelenmis ve bu sekilde robotun basarılı bir biçimde kosması saglanmıstır. Böyleceprojemizde bir sonraki safhaya geçebilmek amacıyla robotumuz revize edilmis ve daha öncebenzetim ortamlarında dogrulaması yapılmıs birçok çalısmamız deneysel olarak dadogrulanmısır. Projenin bitimini takiben adaptif kontrolcü yapılarının robot üzerinde detaylıincelenmesine baslanacaktır.Practical realization of model-based dynamic legged walking and running behaviors onphysical robot platforms is more challenging than their statically stable counterparts. The mainreason behind this difficulty is the critical dependence of related dynamics to systemparameters. This problem is aggravated by the inevitably inaccurate measurements of theseparameters and their time varying nature due to extensive use and associated material fatigue.The main goal in this work is to develop an adaptive controller that supports model-based highperformance running behavior for a one legged hopping robot platform via online once-perstepparameter correction. Actually, in our previous works, we developed an adaptive controllerthat eliminates the steady state tracking error via online parameter adjustment for the Spring-Loaded Inverted Pendulum (SLIP) model in simulation studies. At this point, our aim is to firstextend the proposed adaptive controller strategy for the Torque-Actuated Dissipative Spring-Loaded Inverted Pendulum (TAD-SLIP) model and then present a one-legged hopping robotplatform as a test bench for the proposed method.To this end, we first performed necessary mechanical and electronical revisions on our onelegged hopping robot platform, which was previously developed in our laboratory, to supportits high performance running behavior. Then, we worked on experimental validation of anapproximate analytical solution for the TAD-SLIP dynamics on our robot data. In this context,we first collected single stride tracectories of the robot platform and performed parametricsystem identification to estimate the physical system parameters. After that, we showed howsuccessfully these models can represent robot trajectories.As a last step, we developed a model-based deadbeat controller to regulate the velocity andheight of the robot by using the experimentaly validated approximate analytical solution. Weinvestigated the performance of this model-based controller in various experiments and it hasbeen shown that the robot can successfully track the desired trajectories. Thus, in this project,we presented the revised one-legged hopping robot platform as well as our experimentalinvestigations of some previous studies on the new robot platform. Subsequent to this project,we plan to investigate the performance of the adaptive controllers on our physical robotplatform

Friction and wear behaviour of implanted AISI 316L SS and comparison with a substrate

Ion implantation creates alterations in surface composition or morphology of solids which yield to a modification of physical and especially mechanical properties;, such as hardness and modulus of elasticity. The aim of this study is to focus on the friction and wear behaviour of N-2 and Zr implanted and TiN coated 316L stainless steel and compare with a substrate, Particularly, stainless steels were of interest, because they often display a poor tribological behaviour, which can be improved when they are hardened by incorporating N-2, TiN and Zr and forming a hardened surface zone. The present implantations were shown to improve the friction coefficient as well as the wear resistance of the stainless steel surface. (C) 2002 Elsevier Science Ltd. All rights reserved

Effects of the Mechanical Properties of Composite Laminated Plates on the Free Vibrations

In this study, the effects of mechanical properties for plate's material on the linear free vibrations and the free nonlinear vibrations are investigated using symmetrical modes considering three different types of composite plates. The effects of the mechanical properties of the plate materials on the plate vibrations are shown. The analysis is performed via a simulation program written in Matlab and the finite element method is used

Analytical and Experimental Investigation of the Rotary Inertia Effects of Unequal End Masses on Transverse Vibration of Beams

In this study, the transverse vibration of free–free slender beams with two unequal end masses attached were studied. The effects of the rotary inertia of the end masses on the free vibration of the beam were investigated. An exact frequency equation and the boundary conditions were obtained by using the Euler–Bernoulli beam theory and Hamilton’s principle. Natural frequencies and mode shapes of the beams in transverse vibrations were calculated for various combinations of physical and geometrical parameters, such as mass ratios, the distances between the attachment point and the center of the masses, etc. The effects of an increase in the rotational inertia of the end masses and different mass ratios on the natural frequencies and mode shapes of the beam are presented. It is shown that the increase in the rotational inertia of the end masses had a greater effect at low frequencies of the beam. In addition, experimental tests were performed to validate the obtained analytical results. A good agreement was obtained between the analytical and experimental results. The main scope of this study was to reveal the effects of the rotary inertia of the end masses on the dynamic behavior of the beam. Thus, the aim is to contribute to the understanding of the properties of the end mass and the effect of rotary inertia on the dynamics of end-mass-attached structures. Furthermore, the results obtained from this research are helpful for designing end-mass-attached structures, such as micromechanical sensors, energy harvesters, and Stockbridge-type dynamic absorbers

Tribological properties of coated ASME 316L SS and comparison with a substrate

Coating is a process applied to surface of materials to have thermal insulation, hot corrosion, erosion and oxidation resistance. Due to their combination of high hardness and chemical stability thin titanium nitride and Tinalox PVD coatings have been successfully established in surface engineering. In the present study, wear and friction characteristics of TiN and Tinalox PVD coated ASME 316L stainless steel were investigated and compared with the substrate. To do this, friction and wear tests were done using Tribotester, S/N: 07-128 CSEM machine. Also, hardness variation was determined by means of CSEM Nano-Hardness Tester S/N: 4-113. It was seen that hardness was increased in TiN and Tinalox coated substrates, while friction coefficient and wear rate decreased