Position / force control of systems subjected to communicaton delays and interruptions in bilateral teleoperation

Thesis (Master)--Izmir Institute of Technology, Mechanical Engineering, Izmir, 2012Includes bibliographical references (leaves: 65-68)Text in English; Abstract: Turkish and Englishix, 76 leavesTeleoperation technology allows to remotely operate robotic (slave) systems located in hazardous, risky and distant environments. The human operator sends commands through the controller (master) system to execute the tasks from a distance. The operator is provided with necessary (visual, audio or haptic) feedback to accomplish the mission remotely. In bilateral teleoperation, continuous feedback from the remote environment is generated. Thus, the operator can handle the task as if the operator is in the remote environment relying on the relevant feedback. Since teleoperation deals with systems controlled from a distance, time delays and package losses in transmission of information are present. These communication failures affect the human perception and system stability, and thus, the ability of operator to handle the task successfully. The objective of this thesis is to investigate and develop a control algorithm, which utilizes model mediated teleoperation integrating parallel position/force controllers, to compensate for the instability issues and excessive forcing applied to the environment arising from communication failures. Model mediation technique is extended for three-degrees-of-freedom teleoperation and a parallel position/force controller, impedance controller, is integrated in the control algorithm. The proposed control method is experimentally tested by using Matlab Simulink blocksets for real-time experimentation in which haptic desktop devices, Novint Falcon and Phantom Desktop are configured as master and slave subsystems of the bilateral teleoperation. The results of these tests indicate that the stability and passivity of proposed bilateral teleoperation systems are preserved during constant and variable time delays and data losses while the position and force tracking test results provide acceptable performance with bounded errors

A macro-micro mechanism design for laser cutting process

This paper is organized to provide the novel approaches during the design of a machine to shorten the laser cutting process. Macro-micro manipulation concept is employed for the design of this machine both in the mechanical design and in devising the trajectory planning algorithm. Micro-mechanism design along with its calibration process are also explained since they involve novel approaches in this application domain. Trajectory planning algorithms, which are developed in this work, are discussed based on their applicability to CNC system architecture. Finally, experimental results based on a benchmark workpiece are given and the system design is discussed with respect to these results.Republic of Turkey Ministry of Science, Industry and Technology and Coşkunöz Metal Form Inc. (Project code: 01668.STZ.2012-2

Applying model mediation method to a mobile robot bilateral teleoperation system experiencing time delays in communication

Teleoperation systems consist of two subsystems namely, the master and the slave. Master is used by the human operator to send commands to the slave to achieve a task. In bilateral teleoperation, the interaction forces acquired from the slave sub-system is sent to the master to increase the level of tele-presence. In this kind of a setting, data has to be transferred through a communication line in which package losses and time delays occur. Such deficiencies in the communication line results in stability problems in the system. In this paper, HIPHAD desktop haptic device as the master sub-system and an omni-directional mobile robot as the slave subsystem is used to develop an unlimited workspace teleoperation system. The system’s stability and tracking performance under a constant time delay is measured for direct teleoperation and when model mediation method is applied to ensure stability. The results of the tests are given and the conclusions are derived.The Scientific and Technological Research Council of Turke

Use of hidden robot concept for calibration of an over-constrained mechanism

Overconstrained mechanisms prove useful in applications where high stiffness and low weight is required against high amount of forces while keeping high precision. This study issues a planar two degrees-of-freedom overconstrained parallel manipulator for positioning the end-effector with high acceleration values (>5g) with a positioning precision in the order of 30 micrometers. Since the manufacturing errors were compatible with the end-effector positioning errors, it was required to perform some system identification before the precision and repeatability tests. For the system identification, the end-effector position and motor input values are recorded. However, since the mechanism is overconstrained, the link lengths could not be obtained due to the lack of analytical inverse kinematics solution. In order to cope with this problem, the hidden robot concept is utilized in order to fit a simple kinematic model between the task space and the joint space of the manipulator. Further calibration studies are carried out using the error correction matrix. The test results are presented

Efficacy of different devices in removing calcium hydroxide from the root canal

Objectives: The aim was to compare the efficiency of removing calcium hydroxide (CH) with different devices and irrigants. Materials and Methods: Ten roots were served as positive and negative controls, the remaining roots (n=75) were assigned into 5 respect to the removal techniques: Group (G) I, Master apical file- manual needle irrigation (MNI); GII, Canal Brush (CB)-MNI; GIII, RinsEndo; GIV, Self-adjusting file(SAF)-Vatea; GV, CB+MNI, followed by SAF+Vatea. The roots were grooved longitudinally and split into halves.  Three specimens from each group were randomly selected to evaluate CH remnants under the SEM. A digital camera acquired images of each half of the canal. A scoring system was used to assess amount of residue. Data were analyzed using Kruskal–Wallis and Mann–Whitney U tests (p < 0.05). Results: Remnants of CH were found in all experimental groups. Examining the efficacy of CH removal from the each third of the canal showed that there was a statistically significant difference between the middle (p=0,003) and cervical (p=0,006) thirds. Conclusions: None of the techniques removed the CH medicament completely; the use of the RE and SAF facilitated removal of CH especially from the cervical third

Design and analysis of a parallel mechanism for kinematically redundant hybrid planar laser cutting machine

Conventional planar laser cutting machines cannot achieve high accelerations, because the required precision values cannot be achieved due to the high inertial loads. Machines configured as kinematically redundant mechanisms are able to reach 5-6 g acceleration levels since they include a parallel mechanism with a smaller workspace which is exposed to smaller inertial loads. The study presented in this paper focuses on the design of a parallel planar mechanism to be integrated to the main axes of conventional planar laser cutting machines to achieve higher accelerations of the laser head up to 6 g. Parallel mechanism’s conceptual design and dynamic balancing studies are provided along with the joint clearance effect on precision due to having more joint structures.Republic of Turkey Ministry of Science, Industry and Technology & Coşkunöz Metal Form (Project code: 01668.STZ.2012-2

Bakışımsız bir düzlemsel 5R eyleyicisinin bağlama açına göre tasarımı

İki serbestlik dereceli düzlemsel 5R (R: döner mafsal) mekanizmasının uç noktasının işlevsel çalışma alanına göre mekanizma tasarımı çok farklı başarım ölçütlerine göre yapılabilmektedir. Bu çalışmada uç noktasının yerleşimi nedeni ile kinematik yapısı ve çalışma alanı bakışımsız olan bir 5R mekanizmasının bağlama açısının dik açıya yakın tutulması ölçütü uyarınca işlevsel çalışma alanının tespiti ve de istenilen çalışma alanına boyutuna göre uzuv boyutlarının seçimi ele alınmıştır. Mekanizmanın çalışma alanının tespiti için gerekli kinematik model oluşturulmuş, bağlama açısına göre işlevsel çalışma alanı tespiti irdelenmiş, çalışma alanına gör uzuv boyutlarının belirlenmesi açıklanmış ve de bağlama açısının kuvvet iletimine etkisi tartışılmıştır.There are many performance indices defined for the design of two degrees-of-freedom planar 5R (R: revolute joint) mechanisms according to the dexterous workspace of the end effector. In this study, the performance index was chosen as the transmission angle in order to determine the dexterous workspace of an asymmetric planar 5R mechanism. Also design of link lengths according to a desired dexterous workspace is explained. First, the necessary kinematic model for determining the workspace of the mechanism is constructed. Then the formulation is presented for determining the dexterous workspace according to transmission angle. Finally the effect of the transmission angle on force transmission characteristics is discussed

Comparison of Apically Extruded Debris Associated with Different Nickel–Titanium Systems

ABSTRACTObjective: The aim of this study is to evaluate the influence of different instrument systems on the amount of extruded debris. Materials and methods: A total of 30 extracted mandibular molars with two separate canals and apical foramina in the mesial roots were selected. The root canals (n=10) were randomly assigned to the six groups of file systems as follows: ProTaper Next (PTN), WaveOne (WO), WaveOne Gold (WOG), One Shape (OS), Reciproc (R) and Reciproc Blue (RB). The extruded debris during the instrumentation was collected into Eppendorf tubes, which were weighed and then stored in an incubator at 70°C over a period of five days to evaporate the irrigant. After the incubation process, the Eppendorf tubes were weighed again. The difference between these two measurements, the first one before and the second one after the incubation process, was calculated. Data were statistically analyzed, and the significance level was set at p<0.05. Results: R produced less debris compared to WO. R and PTN files produced significantly less debris compared to the OS files (p < 0.05). Extruded debris in RB and WO groups were not significantly different, while RB produced less debris than WOG and OS (p<0.05). Conclusions: All instrumentation systems allowed for the apical extrusion of the debris. Keywords: Apically extruded debris, Endodontics, Ni-Ti systems   ÖZ Amaç: Bu çalışmanın amacı, farklı nikel titanyum eğe sistemlerini apikalden taşan debris miktarı açısından değerlendirmektir. Gereç ve Yöntemler: Bu çalışmada mesial köklerinde iki ayrı kanal ve apikal foramene sahip toplam 30 adet mandibular molar diş seçildi. Kök kanalları (n = 10) aşağıdaki altı eğe sistemine göre rastgele ayrılmıştır: ProTaper Next (PTN), WaveOne (WO), WaveOne Gold (WOG), One Shape (OS), Reciproc (R) ve Reciproc Blue (RB). İnstrümantasyon sırasında ekstrüde edilmiş debrisler önceden boş ağırlıkları ölçülmüş eppendorf tüplerinde toplandı ve sonra irrigantı buharlaştırmak için beş günlük bir süre boyunca 70 ° C'de bir inkübatörde saklandı. İnkübasyon sürecinden sonra, eppendorf tüpleri tekrar tartıldı. Bu iki ölçüm arasındaki fark hesaplandı. Veriler istatistiksel olarak analiz edildi ve anlamlılık düzeyi p <0,05 olarak belirlendi. Bulgular: R, WO ile karşılaştırıldığında daha az debris taşmasına sebep oldu. R ve PTN eğeleri, OS eğelere göre anlamlı derecede daha az debris taşımına sebep oldu (p <0,05). RB ve WO gruplarında apikalden taşan debris miktarı anlamlı ölçüde farklı değildi ancak RB WOG ve OS'den daha az debris taşmasına sebep oldu (p <0.05). Sonuç: Bütün eğe sistemleri apikalden debris taşırmıştır. Anahtar Kelimeler: Apikal taşma, Endodonti, Ni-Ti sistemler

On kinematically redundant planar laser cutting machines

Alışılagelmiş düzlemsel lazer kesme tezgahları XY düzleminde hareket için X ve Y doğrultularında doğrusal kızaklar üstünde eylemi gerçekleştirirken yüksek atalet kuvvetleri etkisi ile hassasiyet kaybı meydana geldiği için yüksek ivmelere çıkamamaktadır. Son yıllarda bazı yurt dışı bazlı firmalar geleneksel düzlemsel lazer kesme tezgahlarına fazladan eyleyici sistem ekleyerek kinematik olarak artıksıl hibrit mekanizmalar oluşturmuş ve kesici kafa için yüksek ivme seviyelerine çıkabilmişlerdir. Bu çalışmada geçmiş çalışmalarda ve piyasada bulunan yüksek ivmeli lazer kesim makinaları incelenmiştir. Lazer kesim makinalarında kullanılabilecek farklı mekanizmalar, bunların birleşimleriyle hibrit makina oluşturulması ve hassasiyet arttırıcı önlemler bildiri kapsamında irdelenmiştir. Makinanın işi en kısa sürede bitirmesi için eyleyici hareketlerini eniyileyecek kinematik olarak artıksıl robot denetleyicileri de bu çalışma kapsamında araştırılmıştır.Conventional planar laser cutting machines with Cartesian XY motion systems cannot achieve high acceleration values while preserving the desired precision values due to high inertial forces. Recently some foreign companies have integrated redundant manipulators to the conventional planar laser cutting machines and hence obtained kinematically redundant hybrid mechanisms in order to achieve high acceleration values for the laser cutting head. This study reviews high acceleration laser cutting machines that appear in previous studies and in the market. Various types of mechanisms that can be used in laser cutting applications, the hybrid machines hence obtained and the measures for increasing precision are investigated. Also the kinematically redundant robot controllers are investigated for optimization of the manipulator motion in order to minimize the process time.İzmir Yüksek Teknoloji Enstitüsü ve Coşkunöz Metal Form Endüstri ve Ticaret A.Ş

Makro-mikro robotik manipülasyon: Bir lazer kesim çalışması

Thesis (Doctoral)--Izmir Institute of Technology, Mechanical Engineering, Izmir, 2019Includes bibliographical references (leaves: 121-130)Text in English; Abstract: Turkish and EnglishThis dissertation focuses on investigation and devising of proper methodology to utilize a special type of kinematic redundancy, namely macro–micro manipulation, in the scope of robotic science. Briefly, macro-micro manipulation is comprised of two kinematically different mechanisms that have distinct characteristics, which work on macro and micro-scale. Aim of this dissertation is to present the most convenient motion planning and control algorithm to resolve kinematic redundancy for macro-micro manipulation concept. Controller designs, including the motion planning algorithms are devised taking into account the selected industrial case study. Additionally, a general framework controller is developed for macro-micro manipulation. Experiments with industrial setup and simulation verifications are done for the proposed methodologies. It is proven with simulation test results and experiments that the task completion duration for a laser cutting machine is reduced by enhancing the acceleration capability with the macro-micro manipulation. Although the proposed methodologies are implemented for a specific case, it can also be used for other systems considering the versatility of the proposed methodology. The core novelty of this research is the introduction of methodologies in order to achieve the maximum efficiency for the combined use of macro and micro-scaled manipulators. As an outcome of this study, a redundant laser cutting machine that can move with higher accelerations by making use of macro-micro manipulation is developed as a first of its kind in the Turkish machine industry and third of its kind in the world.Bu tez, robotik bilimi kapsamında, özel bir kinematik fazlalık türü olan makromikro manipülasyon için uygun metodolojinin araştırılması ve tasarlanmasına odaklanmaktadır. Kısaca, makro-mikro manipülasyon, makro ve mikro ölçekte çalışan ve belirgin avantajlara sahip kinematik olarak farklı iki mekanizmadan oluşur. Bu tezin amacı, makro-mikro manipülasyon konsepti için kinematik fazlalığı kullanarak en uygun hareket planlama ve kontrol algoritmasını sunmaktır. Endüstriyel uygulama çalışması göz önüne alınarak, hareket planlama algoritmaları dahil olmak üzere denetleyici tasarımları geliştirilmiştir. Ek olarak, makro-mikro manipülasyon için genel bir çerçeve denetleyicisi geliştirilmiştir. Önerilen yöntemler için endüstriyel kurulum ve simülasyon doğrulamaları ile deneyler yapılmıştır. Sayısal sonuç ve deneylerle, bir lazer kesme makinesinin görev tamamlama süresinin, makro-mikro manipülasyon ile hızlanma yeteneğini artırarak, azaltıldığı kanıtlanmıştır. Önerilen metodolojiler belirli bir durum için uygulanmakla birlikte, metodolojinin çok yönlülüğü dikkate alınarak, diğer sistemler için de kullanılabilir. Bu araştırmanın temel yeniliği makro ve mikro ölçekli iki tip manipülasyonun birleşik kullanımı ile maksimum verimliliği sağlayacak metodolojilerin sunumudur. Yapılan çalışmaların bir sonucu olarak, makro-mikro manipülasyon konseptini kullanarak daha yüksek ivmelere ulaşabilen Türkiye makina endüstrisinde ilk, dünyada ise üçüncü lazer kesim makinası uygulaması geliştirilmiştir.TUBITAK (116M272