Nicolae Craciunoiu

AcuBot: a robot for radiological interventions

We report the development of a robot for radiological percutaneous interventions using uniplanar fluoroscopy, biplanar fluoroscopy, or computed tomography (CT) for needle biopsy, radio frequency ablation, cryotherapy, and other needle procedures. AcuBot is a compact six-degree-of-freedom robot for manipulating a needle or other slender surgical instrument in the confined space of the imager without inducing image artifacts. Its distinctive characteristic is its decoupled motion capability correlated to the positioning, orientation, and instrument insertion steps of the percutaneous intervention. This approach allows each step of the intervention to be performed using a separate mechanism of the robot. One major advantage of this kinematic approach is patient safety. The first feasibility experiment performed with the robot, a cadaver study of perispinal blocks under biplanar fluoroscopy, is presented. The main expected application of this system is to CT-based procedures. AcuBot has received Food and Drug Administration clearance (IDE G010331/S1), and a clinical trial of using the robot for perispinal nerve and facet blocks is presently underway at Georgetown University, Washington, DC.

Design of a Test Rig for Vehicle Stabilizer Bar Fatigue Study

In this paper the design, experimental and numerical simulation of a test rig for stabilizer bars fatigue resistance study is presented. A virtual CAD of the test rig is developed, for design and simulation purposes. A dynamic simulation model is developed in ADAMS software, to study the stabilizer bar durability. Strain gauge transducers are used to measure the deformations of the stabilizer bar.

Elastodynamic Analysis of the Sucker Rod Pumping System Mechanism

The paper aims to identify the dynamic response of the oil pumping unit system mechanism using the analytical method and the experimental method. By numerical processing of the developed mathematical models for longitudinal and transverse vibrations of the mechanism connecting rod and walking beam, the time variation diagrams of the linear elastic displacement were obtained in the Maple programming environment. In order to confirm the theoretical results but also for a complex analysis of the entire pumping system, there was determined the force acting upon the polished rod and there were compared the values obtained by calculus and the values experimentally determined for the angle of rotation of the walking beam. Permanent monitoring of the pumping rod mechanical stress and vibration acceleration might contribute to more efficient operation of oil deep extraction wells.

On the Temperature and Chips Types in Milling of an Austenitic Stainless Steel

The cutting process of austenitic alloy is very difficult due to the low conductivity and tendency for built up edge. For this reason is very important to analyze the temperature and chips shape during cutting process. This paper try, based on some experimental results, to study the influence of cutting parameters on the temperature developed during the cutting process. For this, both infrared pyrometer and thermocouple are used to measure in the same time the temperature. Also the chips types is analyzed.

On the Cutting Tool and Workpiece Temperature in Turning of Titanium Parts Used in Automotive Industry

Although they have a high cost, titanium and its alloys have begun to be very used in automotive industry, due to the lightweight and high strength. As is known, an important role to increase the tool life and reduce the wear of cutting tool is the temperature during the cutting process. This paper presents the some researches on the cutting tool and workpiece temperature during the turning process of pure titanium.

Study on the Cutting Temperature and Chips Formation during the Milling of Pure Titanium

In this paper some experimental determinations on the temperature during the milling process of pure titanium is conducted, using different cutting conditions. The results are presented as graphical dependencies and also as a screen capture of the values obtained using an adequate technique for temperature of the cutting process. Some pictures of the chips shape captured during milling process of the pure titanium bare are presented.

Nonlinear Analysis of Temperature during Orthogonal Turning

In this paper orthogonal turning processes are analyzed for different depth of cut. The temperature during the machining is analyzed. The nonlinear dynamics of the orthogonal turning are characterized with fft, phase plane, time delay, embedding dimension and largest Lyapunov exponents. The Lyapunov exponents can be used as a dynamic stability index for the system. The largest Lyapunov exponents for two different depth of cut show the chaotic behavior of the system.

Wavelet Analysis of Humans with Osteoarthritis

In this research proposal we want to develop from kinematic data, measures using thewavelets theory to characterize normal and osteoarthritis knee locomotion. The kinematic data of theradio-carpal flexion-extension angles were analyzed using the wavelet transform. The experimentaldata was acquired with a complex goniometer system. The detail energy for the level 5 is an importantfactor to characterize the osteoarthritis patients and normal subjects.

Dynamics of a Pumping System

In this paper a pumping systems for deep extraction is simulated using SolidWorks and ADAMS. The elastic displacement of a point on the flexible moving cable is analyzed. The dynamics of the system is characterized with phase plane, Poincaré maps, and Lyapunov exponents. The Lyapunovexponents represent the dynamic stability of the system. The largest Lyapunov exponents for three different angular velocity show the chaotic motion of the system

Study on the Applied Tolerances Using Computer Aided Design

Based on the ISO standards, that give the geometric definition and interpretation of tolerances, this paper propose o representation and interpretation for the geometric tolerances applied to the real pieces. In order to do that, based on the 2D layout of the part, a 3D model of the real piece (skin model) is developed. Then, the datum surface and tolerance zone are applied and explained.