Proceedings of the 10th International Conference on Mechatronics
Bucharest, May 19-22, 2011
Preview of Selected Papers
Abstracts of the Proceedings of the 10th International Conference on Mechatronics and Precision Engineering are available at the conference web site, Comefim 10, or here. Selected papers of the conference are published by:
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Journal of Optoelectronics and Advanced Materials. The Journal of Optoelectronics and Advanced Materials is abstracted in Cambridge Scientific Abstracts, and Chemical Abstracts Service – Division of American Chemical Society. JOAM is indexed in Science Citation Index Expanded – Thompson Reuters, Institute for Scientific Information – Thompson ISI Alerting Services, and Materials Science Citation Index – Thompson Reuters.
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Journal of Control Engineering and Applied Informatics. The Journal of Control Engineering and Applied Informatics is indexed in Science Citation Index Expanded - Thompson Reuters, and Index Copernicus International.
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Scientific Bulletin of University Politehnica of Bucharest, Series D - Mechanical Engineering . The Scientific Bulletin of University Politehnica of Bucharest is indexed in Ulrich's Periodical Directory, Scopus, Elsevier SciVerse, and Cambridge Scientific Abstracts.
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Romanian Review Precision Mechanics, Optics and Mechatronics. The Romanian Review Precision Mechanics, Optics and Mechatronics is indexed in EBSCOhost, Ipswich, Massachusetts.
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Mecatronica, Journal of the Romanian Society of Mechatronics.
Previews of 30 selected papers of the conference in pdf format are available below. Full access to the papers may be granted by the authors:
01. Detection of Bio-Chemical Reactions through Micro Structural Interactions
M. Changizi*, D. Roman*, I. Stiharu*
* - Department of Mechanical and Industrial Engineering, Concave Research Centre, Concordia University, Montreal, Canada
This paper presents a highly accurate and repeatable method to detect micro-level bio-chemical reactions using the interaction between microstructure and the reactant mixed with the chemical marker. The method produces a recognizable deflection signature of the cantilever beam. Such deflections could be very large such that they exceed the linear deflection range. For determination of the large deflections of the tip of cantilever beams, an exact method is proposed. This method is using symmetry groups for finding the closed-form solution which could be applied for any boundary condition case. The open literature provides solution only for two particular loading cases: point force and point moment.
Corresponding author: M. Changizi
02. Comparative Study of Electromechanical Response in Some Dielectric Elastomers
V. Carlescu*, D. Olaru**, F. Breabana**, Gh. Prisacaru**
* - Université Lille Nord de France, F-59000 Lille, France; Université d’Artois, LGCgE, F-62400 Béthune, France, CRITTM2A – IUTB/S2T-EHVL
** - Machine Elements and Mechatronic Department, Gheorghe Asachi Tehnical University of Iasi, RomaniaDielectric elastomers, a subclass of electroactive polymers EAP materials, are very promising for actuator and sensor applications due to their interesting properties such as high energy density, high strain levels from 10 to 380 % and fast response in order of milliseconds. Polymer films were sandwich between two rigid electrodes and subjected to high DC electric fields. We investigate the transverse strain responses of some dielectric elastomer actuators DEA using an eddy current displacement sensor. Electric-field-induced thickness strains in order of micrometers were measured at different high DC step voltage and a quadratic dependence was observed. A comparison has been made between three categories of elastomers. The preliminary results show that performance of the actuators not only depends on the material properties but it is also a function of the actuator structure and electrode materials. We also concluded that these materials may be candidates for actuator materials in micro-actuation mechatronic systems.
Corresponding author: Vlad Carlescu
03. Nanorobotic Systems for Nanomanipulation and Nanopositioning
G. Gheorghe*, L. Badita**, S. Istriteanu*, V. Despa**
* - National Institute of Research and Development in Mechatronics and Measurement Technique, Bucharest, Romania
** - Faculty of Materials Engineering, Mechatronics and Robotics, University of Targoviste, RomaniaNanorobotics is currently a much studied field by the international scientific world. Numerous applications of nanorobotics make it to expand in several areas. This occurs through the integration of several disciplines, including nanofabrication processes used to produce nanorobots, nanoactuators, nano-sensors and nanometer scale physical modeling. Some of the most important applications of nanorobotics are nanopositioning and nanomanipulation. These, in turn, find many other applications to produce different MEMS/NEMS systems, in materials science, biomedical sciences, engineering sciences, etc. Taking into account the importance of this field, we wrote this review in order to present a part of actual nanorobotic systems technology.
Corresponding author: L. Badita
04. Electrothermic Carbon Microactuator
M. Ignat*, G. Hristea*, P. Budrugeac*
* - National Institute of Electrical Engineering Research –Advanced Research, Micro and
Nanoelectrotechnologies, Bucharest RomaniaThis paper provides the first study of the electrothermic behavior of a carbon material based on formic acid-GIC (formic acid-graphite intercalation compound) and presents some electrothermic micro actuator functional structures.
Corresponding author: M. Ignat
05. Piezoelectric Microgenerators for Body Energy Harvesting
M. Ignat*, G. Zarnescu*, A. Catanescu*
* - National Institute for R&D in Electrical Engineering ICPE-CA, Department of Micro and Nanoelectrotehnolog, Bucharest, Romania
The authors are approaching the energy harvesting concept - which includes piezoelectric microgenerators and represents the recovery of energy from the environment and the conversion of mechanical, acoustic, or chemical energy into electrical energy. Piezoelectric microgenerators are used to power wireless microsensors used for monitoring resistance systems in buildings, or physiological and environmental parameters.
Corresponding author: M. Ignat
06. Modeling of Material Properties for MEMS Structures
G. Ionascu*, C. Comeaga*, L. Bogatu*, A. Sandu**, E. Manea***, D. Besnea*
* - Mechatronics and Precision Mechanics Department, Politehnica University of Bucharest, Romania
** - Department of Strength of Materials, Politehnica University of Bucharest, Romania
*** - National Institute for Research & Development in Microtechnology of Bucharest, RomaniaThe paper presents a combined experimental and theoretical study to determine the effective dynamic Young’s modulus for the mechanical structure of a silicon microaccelerometer. The resonance – natural - frequencies of the suspension arms of accelerometer were measured using MSA-500 Micro System Analyzer and, then, introduced in analytical expressions in order to find the effective dynamic Young’s modulus. The obtained results were used to validate the model of numerical simulation relative to the measured resonance frequencies of analyzed MEMS accelerometer.
Corresponding author: Georgeta Ionascu
07. Recent Achievements and Trends in Laser Welding of Thin Plates
D. Iordachescu*, M. Blasco*, R. Lopez*, A. Cuesta*, M. Iordachescu**, J. L. Ocana**
* - UPM Laser Centre, Polytechnic University of Madrid, Spain
** - Materials Science Department, ETSI Caminos, Polytechnic University of Madrid, SpainLaser Welding (LW) is more and more chosen as manufacturing process due to its advantages, namely capability of joining small dimension parts, opportunities for joining of special materials, less Heat Affected Zone, good repeatability, high speed etc. Nowadays, LW is of particular interest in manufacturing small mechatronics parts of mechanic, electric or electronic nature. This paper underscores several achievements in three key-processes, namely classical LW, laser hybrid welding (LHW) and remote laser welding (RLW). These results were obtained at the UPM Laser Centre (CLUPM) of Polytechnic University of Madrid (Universidad Politécnica de Madrid) with a CO2 laser of 3350 W dedicated to RLW of thin sheets for automotive and other sectors, and with a Nd:YAG laser of 3300 W, respectively. The second is operated by a 6-axis ABB robot and is meant for various laser processing methods, including welding. Several important applications experimented at CLUPM and recently implemented in industry are briefly presented: RLW of coated sheets (with Zn or Al), LW of thin sheets of stainless steel and carbon steel (dissimilar joints), LW of high strength automotive sheets, LW versus laser hybrid welding of Double Phase steel thin sheets, LW of Shape Memory Alloys (NiTi). The way in which the team of CLUPM has addressed some knowledge gaps related to LW, LHW and RLW are underscored, together with the benefits of the new technologies for both science and industry.
Corresponding author: Jose Luis Ocana
08. Refractive Index Discontinuities in Fiber Optic Connectors
N. Lambrache*, J. Pereira*, A. Torobin*
* - Alef Photonics, Ottawa, Canada
Connector loss variability has an important impact on planning and developing fiber optics networks. Interdisciplinary design considering optical and contact mechanics phenomena at the interface between connected waveguides with physical contact is a key element in providing sound recommendations for technology. The authors focus on studying the influence of refractive index discontinuities occurring on fiber optic connectors with physical contact and suggest design and manufacturing approaches for controlling it.
Corresponding author: Nicholas Lambrache
09. Mode Transforming Properties of Taper Microlensed Fibers
N. Lambrache*, H. Teimoori*
* - Alef Photonics, Ottawa, Canada
Drowned tapered and microlensed single-mode fibers offer significant manufacturing advantages as waveguide couplers. However, controlled manufacturing requires a better understanding of beam propagation in such photonics devices. The authors investigate the mode transforming properties of drowned tapered and microlensed fiber optics and suggest optimal geometries.
Corresponding author: Nicholas Lambrache
10. Micromachining of 2D-3D Structures with High Intensity Laser Pulses
J. L. Ocana*, C. Molpeceres*, J. Garcia-Ballesteros*, S. Lauzurica*, D. Iordachescu*
UPM Laser Centre, Polytechnic University of Madrid, Spain
Nowadays MEMS, fluidic devices, advanced sensors, biomedical devices and instruments etc. are important applications for strategic sectors. These are demanding suitable tools for materials processing, especially for developing tasks in different kind of materials and geometries around the micron, since this dimensional range emerged at the crossroad of nanotechnologies and conventional fabrication techniques. Specific laser based machines for each process of interest (initially working only in 2D) were rapidly developed, and an important gap has been generated, from the fabrication point of view, in targeting fully 3D applications. This paper briefly describes the design and notable applications of a multi-axis laser micromachining workstation based on the main concept of flexibility that was developed at the UPM Laser Centre of the Polytechnic University of Madrid (Universidad Politécnica de Madrid). This system integrates an advanced 6-axis positioning system and two UV laser sources, excimer and DPSS working in nanoseconds pulse regime, for precision 3D micro-machining of complex parts. A short description of the most relevant features of this micro-manufacturing cell is provided. Advanced materials (including composites) were machined at a dimensional range of microns for the processed zones. The main issues overcame by the authors in generation of 2D/3D structures by high intensity laser pulses with direct incidence are briefly described. Several examples of the applications achieved with this system, including processing of advanced sensors, organic materials for biomedical devices and metallic materials for important industrial sectors are presented.
Corresponding author: Jose Luis Ocana
11. 3D Imaging of Indoor Environments with Mobile Photocamera
A. O. Trufasu*, A. N. Cuta*, A. Trufasu**
* - University Politehnica Bucharest, 050098, Romania
** - Gunnar Optiks, 705 Palomar Airport Road, Suite 100, Carlsbad, CA, 92011, California, USAThis paper presents an algorithm for full 3D imaging of indoor environments with mobile shooting camera. Data is acquired by slow-moving photo-camera equipped with two 2D laser range finders. Present approach combines an efficient scan matching routine for camera pose estimation with an algorithm for approximating environments using flat surfaces.
Corresponding author: A. O. Trufasu
12. A Test Bench to Study Bio-Inspired Control for Robot Walking
K. B. Arikan*, B. Irfanoglu*
* - Mechatronics Engineering Department, Atilim University, Ankara, Turkey
Test bench to study robot walking within the predicted structures of biological control systems is discussed. Physical system is briefly presented with components. Kinematic model and evolutionary way of gait generation for the leg structure in test bench is discussed. Different forms of gaits can be found by genetic optimization using patterns formed by central pattern generators.
Corresponding author: K. B. Arikan
13. Hardware and Software Structure of a Pneumo-Hydraulic Positioning System
M. Avram*, D. Duminica*, C. Bucsan*, V. Constantin*
* - Mechatronics and Precision Mechanics Department, Politehnica University of Bucharest, Romania
The paper presents the hardware and software structure of a linear unit for pneumo-hydraulic positioning, developed by the authors. The unit features two identical cylinders, one pneumatic and one hydraulic, mounted in parallel. The speed control is achieved by the use of two check valves of original construction. Mathematical model, simulation results and experimental results are also provided.
Corresponding author: Mihai Avram
14. Adaptive Control of a Virtual Mini Robot with Autonomous Displacement Using a Virtual Sensor System
D. Bacescu*, S. Petrache*, N. Alexandrescu*, D. Duminica*
* - Mechatronics and Precision Mechanics Department, Politehnica University of Bucharest, Romania
The paper presents the latest version of a family of optoelectronic sensors used for the control of mini robots without embarked sensors. The optoelectronic sensors are based on the concept of virtual sensor. The last section of the paper focuses on the technical solution developed for the transfer of the light source attached to the mini robot on the tracking and control equipment, using a laser directed to a reflecting sphere attached to the mini robot.
Corresponding author: Daniel Bacescu
15. Design and Testing of Two Mechatronic Systems for Robotized Neurorehabilitation
G. Belforte*, G. Eula*, S. Sirolli*, S. Appendino**
* - Department of Mechanics, Politecnico di Torino, Technical University of Turin, Italy
** - IIT - Italian Institute of Technology - Center for Space Human Robotics, Turin, ItalyThis paper illustrates the design and the testing of two mechatronics prototypes useful for robotized neurorehabilitation and for motor training assessment. The two machines are called Bra.Di.P.O. (Brain Discovery Pneumatic Orthosis) and P.I.G.R.O. (Pneumatic Interactive Gait Rehabilitation Orthosis). They are electro-pneumatically controlled. This approach offers many of advantages: pneumatic systems give comfortable interaction between machine and patient; they are safe, clear and easy to connect to hospital plant; they are MR-compatible. These prototypes have been tested both in laboratory and at hospital and results obtained are good.
Corresponding author: Gabriella Eula
16. Virtual Prototyping of a Car System Used for Impact Simulations
G. Gherghina*, D. Popa*, St. Ciunel*
* - Faculty of Mechanical Engineering, University of Craiova, Romania
This paper presents issues concerning the use of 3D CAD systems in virtual prototyping, in this case a complex virtual model for a car system used for impact simulations. Virtual prototyping is a process that uses a virtual prototype instead of the physical prototype for testing and evaluating specific elements of the designed product. Virtual prototype is created on the computer closer to the actual characteristics and operating conditions so as to allow the simulation to perform the role for which it was designed. The 3D model has been exported into simulation software able to perform kinematics simulations and finite element analysis, at the same time. With that virtual model were analyzed different situations similar with car crash. Results of simulations have been analysed and compared with measurements made on the real models.
Corresponding author: George Gherghina
17.Vision Based Autonomous Navigation in Unstructured Static Environments for Mobile Ground Robots
D. Novischi*, C. Ilas*, S. Paturca*, M. Ilas**
* - Department of Electrical Engineering, Politehnica University of Bucharest, Romania
** - Department of Electronics and Telecommunications, Politehnica University of Bucharest, RomaniaThis paper presents an algorithm for real-time vision based autonomous navigation for mobile ground robots in an unstructured static environment. The obstacle detection is based on Canny edge detection and a suite of algorithms for extracting the location of all obstacles in robot’s current view. In order to avoid obstacles we designed a reasoning process that successively builds an environment representation using the location of the detected obstacles. This environment representation is then used for making optimal decisions on obstacle avoidance.
Corresponding author: Constantin Ilas
18. Hybrid Micro-Nano Robot for Cell and Crystal Manipulations
F. Ionescu*, K. Konstadinov **, St. Arghir***, D. Arotaritei ****
* - Steinbeis Transfer Institute Dynamic Systems, University of Applied Sciences HTWG Konstanz, Germany.
** - Bulgarian Academy of Sciences-Sofia
*** - University Politehnica Bucharest, Romania
**** - University of Medicine and Pharmacy of Iasi, RomaniaThe paper presents some Computer Assisted Engineering (CAE) aspects concerning the achievement of a hybrid actuated micro-nano robot. Starting from a unitary concept Control- Design, different kinematic solutions were developed and compared, before a decision upon the structure was selected. Multiple closed loop simulations were performed via MATLAB/Simulink, Solid Dynamics and ANSYS software. The experimental results for the nano-stages/actors were run for two XY orientations with a range of 240 arcsec and for translation in Z direction in a stroke range of 65μm, with a system resolution of 10nm. Additional identification and reconstruction of the hysteresis curves were obtained and implemented in the model by using a Neuro-Fuzzy technique. Two hardware systems were developed for the micro and Nan robot respectively. Corresponding software HMI capable also of joystick tele-manipulation was developed.
Corresponding author: Florin Ionescu
19. Lung Ventilators Parameters Determination
B. M. Ciurea*, D. D. Palade** and S. Kostrakievici***
* - Dräger Medical Romania, Bucharest, Romania
** National Institute of Research & Development for Mechatronics and Measurement Technique, Bucharest, Romania
*** University Politehnica of Bucharest, Dept. of Bioengineering and Biotechnology, RomaniaAn integrated test unit that can automatically determine the ventilators parameters provided by pulmonary ventilation equipment is being developed. Several sensors mounted to a computer via a data acquisition card are used for automatic determination of the parameters. A program that can automatically extract the ventilator's parameters is developed using the LabView software.
Corresponding author: B. M. Ciurea
20. Contact Mechanics and Friction on Novel Linear-Motion Bearing with Helical Insert
N. Lambrache*, M. Nistor**, N. Alexandrescu**
* - Alef Photonics, Ottawa, Canada, e-mail: Nicholas.Lambrache@alefphotonics.com
** - Politehnica University of Bucharest, Dept. of Mechatronics, Bucharest, e-mail: mircea.nistor@upbHelical inserts provide convenient service on low-friction linear-motion bearings. However, effective design requires a better understanding of contact mechanics and friction phenomena involved in the functioning of such bearings. The authors assume predominantly elastic contacts between the elements of the bearing, analyze the local deformations and pressure distribution and discuss experimental solutions for the evaluation of the friction coefficient in such bearings.
Corresponding authors: Nicholas Lambrache, Mircea Nistor
21. A Method for Forward Displacement Analysis of 3-RRP and 3-PRP Planar Parallel Manipulators
Sevasti Mitsi*, Konstantinos D. Bouzakis*, Gabriel Mansour*, Iulian Popescu**
* - Mechanical Engineering Department, Aristotle University of Thessaloniki, Greece
** - Faculty of Mechanics, University of Craiova, RomaniaThe paper presents a method for the forward displacement analysis of 3-RRP and 3-PRP planar parallel manipulators including the RP-RP-RP third-class Assur group. The aim of this analysis is to find all possible configurations of the parallel planar mechanism for one given set of input joints values. The proposed method leads to a non-linear system of three equations with three unknown parameters. Using a successive elimination procedure, a polynomial equation of eighth order in one unknown is obtained. The real solutions of the polynomial equation correspond to the assembly modes of the planar parallel mechanism. The maximum number of the assembly modes of the investigated manipulators is two. Furthermore, a numerical application of the proposed method is presented.
Corresponding author: Sevasti Mitsi
22. Control System for Pneumatic Robot
V. Constantin*, M. Avram*, S. Miu*, C. Bucsan*
* - Faculty of Mechanical Engineering, University Politehnica of Bucharest, Romania
The paper deals with a control system built for a pneumatic robot with 5 mobility ranks. The robot is controlled using a USB-6009 USB board connected to a PC, along with circuitry needed to adapt the signals. The paper shows how the difference between the number of available DIO lines on the DAQ board and the number of signals needed to control the system is resolved using regularly available integrated circuits and the program developed in LabVIEW to control the robot.
Corresponding author: Constantin Bucsan
23. A Novel Approach to Master and Slave Control by Force Feedback Based Virtual Impedance Controller
Nobuhiro Iwase*, Ryosuke Horie**, Toshiyuki Murakami***
* - Keio University, Japan
A field of research which deals with tactile sensation is called haptics. Many researchers have been investigated haptics in recent years. In the past research, 4ch bilateral controller based on torque/force sensorless approach is developed so as to achieve high transparency as teleoperation systems. In actual system with geared motor, however, the high transparency leads to instability because of disturbances. In particular, the geared motor has a large joint friction which affects the torque/force sensorless control, though its cost is low. This means that the high quality of tactile sensation is not expected in case the geared motor is used in experimental system. To improve the effect of friction, linear motor is often utilized in the past research, though its cost is high. To address this issue, this paper focuses on a novel control strategy to realize low cost teleoperation systems based on the geared motor, that is, master and slave systems. To reduce the effect of joint friction, a novel approach to master and slave control by force feedback based virtual impedance controller is proposed. By using the proposed method, position and force controllers can be designed independently and it is one of remarkable features. To verify the validity of proposed method, the performance of the controller is analyzed and evaluated by using Reproducibility and Operationality. Furthermore experimental validation is conducted with 1-DOF manipulator.
Corresponding author: Toshiyuki Murakami
24. Locomotion and Reconfiguration of a Modular Robotic Chain
G. M. Bobocea*, C. Niţu*, B. Grămescu*
* - Department of Mechatronics and Precision Mechanics, University Politehnica of Bucharest, Romania
The paper deals with a modular robotic system, which is designed for reconfiguring, in order to achieve both walking and crawling locomotion. Its mechanical architecture and control system are presented. A modified robotic module, with 2 degrees of freedom, is proposed, for which the influence of the robot geometry upon the locomotion and self reconfiguration strategy is pointed out, by simulations performed in a virtual environment.
Corresponding author: Constantin Nitu
25. Object Recognition Using a Smart Camera
C. Pop*, A. Davidescu*, F. Moldovan*
* - Mechatronics Department, University Politehnica of Timisoara, Romania
This paper presents a general approach regarding the computer vision and object recognition and emphasizes the importance of the subject. The most common applications involving object recognition are also described. In this context the authors are introducing an application developed with Vision Builder for Automated Inspection and linked with a smart camera for identifying typical objects. The proposed method can be implemented in further research for automated assembly operations with industrial robots.
Corresponding author: Cristian Pop
26. UV Light Curing Adhesive for Optical Assembly Application
G. Sorohan *, A. O. Trufasu **, D. Rizescu**
* - ProOptica SA, Bucharest, Romania
** - Department of Mechatronics, University Politehnica Bucharest, RomaniaUV light-curable adhesives cure in seconds upon exposure to long wave ultraviolet light and/or visible light, heat, or with an activator. Light-curable adhesives optimize the speed of automated assembly, enable 100% in-line inspection, and increase product throughput. Industrial adhesives are available for glass assembly, plastic sealing, metal bonding, and as well as for joining dissimilar substrates.
Corresponding author: Georgeta Sorohan
27. Mechatronic System Used for Flow Controlling of Hydraulic Pumps with Axial Pistons
Alina Spanu*, N. Alexandrescu*
* - University Politehnica of Bucharest, Romania
The paper aims to emphasize the main technical performances of the mechatronic system designed in order to control the flow of hydraulic pump with axial pistons. The control method is a continuous one and refers to a very accurate positioning system with mechanical feedback. By solving the mathematical model of the entire system with dynamic conditions, we have concluded that the theoretical piston displacement is inside an acceptable range. This could be a method for improving the efficiency of the hydraulic pump and of the actuated system too.
Corresponding author: Alina Spanu
28.ZigBee Wireless Network Based Monitoring Systems
Sever Pasca*, Mihaela Cârjeu**, Istvan Sztojanov*
* - University Politehnica of Bucharest, Department of Applied Electronics and Information Engineering, Bucharest, Romania
** - Technical University of Aachen, GermanyApplications that transfer data wirelessly tend to be more complex than wired ones. Wireless protocols make stringent demands on frequencies, data formats and timing of data transfers, security and other issues. Application development has to consider the requirements of the wireless network in addition to the product functionality and user interfaces. Using wireless networks in Mechatronics can be very useful and challenging in order to improve the general performance. The authors studied the opportunity of setting up Monitoring Systems based on a ZigBee Wireless Network Standard. The proposed systems were set up, tested and the minimal Hardware and Software requirements for them were determined.
Corresponding authors: Istvan Sztojanov, Sever Pasca, Mihaela Carjeu
29.Fault Diagnosis of Roller Bearings Using the Wavelet Transform
I. Tsiafis*, K. Bouzakis*, A. Kaplanis**, A. Karamanidis**, T. Xenos **
* - Mechanical Engineering Department, Aristotle University of Thessaloniki, Thessaloniki, Greece
** - Department of Electrical & Computer Engineering, Aristotle University of Thessaloniki, GreeceBall bearings are perhaps the most widely used machine elements and a lot of important and expensive mechanic systems are based on them. Thus, it is necessary to establish a method to detect faults in order to keep the systems running properly. Fault identification of rolling element bearings employing condition monitoring techniques has been the subject of extensive research for the last two decades. Vibration signals of machines provide the dynamic information of the machine condition taking into account the fact that whenever the rolling element encounters a defect, a short duration impulse is generated. These signals are very useful for fault diagnosis. In this paper, the Fast Fourier Transform FFT is initially employed for a first comparison between healthy and defective bearings. Then, the main signal analysis is performed using the Wavelet Transform Method WTM which proves very effective in problems of this type.
Corresponding author: Ioannis Tsiafis
A.Zaid *, D. Besnea**, N. Baran **, Al. Patulea**
* - Al-Balqa Applied University of Engineering Technology Amman Jordan
** - Department of Precision Engineering, and Mechatronics, University Politehnica of Bucharest, RomaniaThe paper justifies the need for measuring the concentration of oxygen dissolved in stationary waters; in order to perform accurate measurements, the oxygen probe must be displaced inside water with a speed greater than 0.3m/s. The constructive solution of the driving mechanism, its function and the results of the performed measurements are exposed.
Corresponding author: A. Zaid
