Naci Zafer

Eskişehir Osmangazi University | ESOGU · Department of Mechanical Engineering

Background and PurposeSeverity of vibrations encountered in Armored Tracked Vehicles (ATV) is comparatively much higher as compared to those in wheeled vehicles. Because ATV hull structures transmit these vibrations to various mechanically connected sub-systems, the transfer of vibrations to weapon systems through the body and mechanical components...

Haptic devices are electromechanical systems designed for achieving real-time interactions with virtual or teleoperation environments. They are used in applications where both position tracking and force feedback are required for creating realistic kinesthetic perceptions to users. Depending on their architecture, these devices may have serial, par...

This article is concerned with the haptic deformation display of discrete viscoelastic surfaces by means of a human fingertip. The virtual surface of a deformable quadrilateral mesh is interactively deformed by a Kelvin–Voigt soft fingertip model attached to the end-effector of a haptic interface device. In achieving this task, a nonlinear constitu...

This paper is concerned with compliant haptic contact and deformation of soft objects. A human soft fingertip model is considered to act as the haptic interface and is brought into contact with and deforms a discrete surface. A nonlinear constitutive law is developed in predicting normal forces and, for the haptic display of surface texture, motion...

This work presents the design and implementation of a genuine mechatronic system enabling contact free tracking of an operator’s finger position. The variation in finger-position is detected by means of a micro-processor-based ring-shaped optical sensing system and the obtained data is then used to actuate a one DOF device driven by a unipolar step...

Bu çalışmada, viskoelastik yüzeylerin haptik olarak algılanması ve deformasyonu ele alınmıştır. Haptik temas, yumuşak yapıda bir parmak modeli ile sanal viskoelastik bir yüzey arasında tanımlanmış ve lineer olmayan gerçekçi bir model geliştirilerek formüle edilmiştir. Gerçeklik algısı kalitesinin arttırılması amacıyla yüzey üzerindeki harekete LuGr...

In this article, a constraint-based controller is developed for two-manifold oriented viscoelastic surfaces that guarantees smooth and compliant haptic rendering. The approach is direct and uses a pseudo-inverse projection of the haptic device end effector onto the virtual surface. The rendering algorithm enables the user to freely move a soft fing...

In this work, stability of chatter in orthogonal cutting is investigated in order to identify the critical spindle speeds. The process is modeled by a second-order linear delay-differential equation and the characteristic equation is analyzed in formulating the continuous stability boundaries, explicitly for any given range of the spindle speeds. M...

Gas pressure regulators are widely used in both commercial and residential applications to control the operational pressure of the gas. One common problem in these systems is the tendency for the regulating apparatus to vibrate in an unstable manner during operation. These vibrations tend to cause an auditory hum in the unit, which may cause fatigu...

This paper presents a new stable controller design for use with a general 6-d.o.f. robotic haptic device. A virtual manipulator concept is developed that couples the haptic device kinematics with the constraints of a simulated manipulator. Using impedance-based constraints, the haptic device is controlled to oppose applied forces in directions orth...

This paper presents a direct method for haptic rendering of a virtual object in which the object is represented as a virtual kinematic chain (virtual manipulator). The joint angles of the virtual manipulator (VM) are considered as parameters for the object's surface. The present algorithm is based on a closest-point approach that determines the joi...

This work presents a commentary, of the article published by Asl and Ulsov (2003, ASME J. Dyn. Syst., Meas., Control, 125, pp. 215-223). We show by an example that their method leads to inaccurate results and is therefore erroneous.

Stabilization of time delay systems is currently a mainstream of research. In this paper, a delayed feedback controller is considered for internet-based teleoperation, where the master and the slave manipulators are bilaterally connected through a communication channel. A frequency based approach is employed for the stability analysis of teleoperat...

A robotic exoskeleton is coupled with the human operator's hand. The purpose is to maintain the relative positioning between the exoskeleton and the human operator's hand as it moves freely. A microprocessor-based optical sensor is utilized as part of a feedback control system for the high-speed guidance of the robotic exoskeleton. A photo voltaic...

In machine tools, there is always the trend of increase in the desired spindle speed or the number of workpieces machined in a given time. This trend calls for an increase in the amount of material removed in a given time from the workpiece surface. High spindle speed and the increase of cutting depth cause undesirable vibrations known as chatterin...

İmalat sektöründe çalışan işçiler kullandıkları makina veya takım tezgahında bir arıza olması durumunda, arızanın bir an önce giderilmesi için bu işten sorumlu bakım mühendisine başvururlar. Bakım mühendisi aslında sadece sorun çıktığında devreye girmez, diğer zamanlarda da rutin bakım işinin başındadır. Rutin bakım aslında imalat sektöründe önemi...

Bu çalışmada makine imalat sanayinde vazgeçilmez yeri olan konvensiyonel takım tezgahlarının tasarımına örnek olarak bir vargel tezgahının tasarlanması incelenmiştir. Bunun için de Makine Kimya Endüstrisinin PY 600 tipli MKE FRITZWERNER lisanslı 4 kW motor gücündeki vargel tezgahı ele alınmıştır. İstenen özellikteki bir vargel tezgahı ve literatüre...

Bu makale, bir vargel tezgahına ait kulis mekanizmasını baz alarak, takım tezgahlarının dinamik dengelenme problemini ele almaktadır. Dinamik analiz için iki farklı metot kullanılmış ve bu metotların karşılaştırılması yapılarak en uygun çözümün aranması yoluna gidilmiştir. Bu metotlardan ilki, grafo-analitik (N.I. Mersalov yöntemi), ikincisi de Kan...

In the approach presented in this research, a six DOF industrial manipulator is used as the master device to provide haptic feedback to the operator. In order develop effective constraints between the motion of the slave and master, a virtual manipulator concept is developed that couples the actual robotic kinematics with the constraints of the sim...

Mechanical manipulators are commonly used in manufacturing applications to aid in the handling of large, bulky, or dangerous materials. Often these heavy lift assist devices are designed to lift a variety of payloads and are controlled by a human operator A recent trend has been to automate more of the function of the manipulator and collocate the...

A recent progression of heavy lift assist device is to place the human operator closer to the end effector to provide close coupling of the operator input and the payload. This close coupling of the human for control and the power of a heavy lift assist device provides improved accuracy with ease of handling in the case of heavy and bulk objects. H...

Assembly operations require high speed and precision with low cost. The manufacturing industry has recently turned attenuation to the possibility of investigating assembly procedures using graphical display of CAD parts. For these tasks, some sort of feedback to the person is invaluable in providing a real sense of interaction with virtual parts. T...