Establish Measurement System for Vibration Lab Unit Using Arduino

Journal of Engineering Research and Reports 15(2): 43-50, 2020; Article no.JERR.59516 ISSN: 2582-2926 Establish Measurement System for Vibration Lab Unit Using Arduino Haithem Elderrat1, Nasseradeen Ashwear1*, Omr Aweib1 and Ali Elmahrouq1 1 Mechanical Engineering Department, Faculty of Engineering, Misurata University, Misurata, Libya. Authors’ contributions This work was carried out in collaboration among all authors. Authors HE and NA designed the study, performed the statistical analysis, wrote the protocol and wrote the first draft of the manuscript. Authors HE and OA managed the analyses of the study. Authors NA and AE managed the literature searches. All authors read and approved the final manuscript. Article Information DOI: 10.9734/JERR/2020/v15i217143 Editor(s): (1) Dr. Guang Yih Sheu, Chang-Jung Christian University, Taiwan. Reviewers: (1) Marcos Aurélio Ayres da Silva, Federal University of Piauí, Brazil. (2) Odilon Linhares Carvalho Mendes, Instituto Tecnológico de Aeronáutica, Brazil. Complete Peer review History: http://www.sdiarticle4.com/review-history/59516 Original Research Article Received 24 May 2020 Accepted 31 July 2020 Published 07 August 2020 ABSTRACT As science and technology develop quickly, suitable measurement system is becoming more achievable. In dynamics of structures, measuring vibrations take a serious view during the process of design and construction to avoid resonance. The main objective of this study is to establish a vibration measurement system for a laboratory vibration unit by using a virtual instrumentation system. The Arduino microcontroller is used as the receiver of the electrical signals coming from the displacement sensor, which is connected to the vibration unit. The microcontroller then processes the electrical signals and send it to LabVIEW software on the computer for processing. The established measurement system is able to calculate the vibration of the moving body. Hence, the natural frequency of the system could be determined, and shock absorber for the unit could be designed. Results have been validated using calculated theoretical results of the unit. Thus, the unit is ready to conduct laboratory experiments on the concept of mechanical vibration. Keywords: Mechanical vibrations; vibration measurements; structures dynamics. _____________________________________________________________________________________________________ *Corresponding author: Email: ashwear@mech.kth.se; Elderrat et al.; JERR, 15(2): 43-50, 2020; Article no.JERR.59516 1. INTRODUCTION hardware equipment and some software programs are available in the university. Lab’s vibration unit is one of the equipment. However, the measurement system of this unit is not available; such missing makes the unit useless. Therefore, this article aims to establish a measurement system for the vibration unit lab at the university by using an Arduino microcontroller and LabVIEW software. This paper is consisted of presenting the importance of measurement system with paying more attention to vibration measurement system by virtual instrumentation. Then, presenting establish measurement system for the lab vibration unit by using Arduino. Finally, the theoretical calculations and experimental results are presented and compared. A suitable measurement system is essential in the field of technology. It has an important effect for the engineering system, such as control systems in electrical plants, performance monitoring of machines, measurement of the roughness of vehicle roads, and monitoring nuclear plant [1-2]. There are a large number of previous studies in the metrology field and design measurement instrumentation, for instance; assessment of surface roughness using the Linear Variable Differential Transformer (LVDT) and an Arduino mega microcontroller as a receiver for data transmission to the computer was introduced [3]; Such system was developed an efficient and cost-effective approach to measuring surface roughness. Muhammad et al. [4] published a study on liquid level detection techniques. The study included the creation of a small range by LVDT, which is used in detecting water, petroleum and gasoline levels, through the sensitivity of the differential converter resulting from the linear displacement works with good precision. Joshi et al. [5] studied the measurement system in civil application such as the extensive use of the rail to measure dynamic displacement and detect vibrations in structures. Masi et al. [6] studied the effect of magnetic fields and they argue that fixed or variable magnetic fields could affect the performance of the measurement system. 2. MEASUREMENT OF VIBRATION Vibration means the state of an object moving repetitively back/forward, right/ left or up/down and is generally expressed by Frequency (Hz), Displacement (μm, mm), Velocity (mm/s, cm/s), 2 and Acceleration (m/s , g). Measurement of vibration is an important topic in applications and equipment. An important reason is to avoid resonant conditions such as those that destroyed the Tacoma Narrows Bridge in 1940, three months after its construction. In addition, measurement of input and output vibrations of any system enables engineers to determine the model parameters (mass, stiffness, and damping) of a system, and with these parameters determine the natural frequency of the system. Vibration measurement is used not only when the problem occurs but also when the daily maintenance is performed. The production system is kept in operation by detecting the deterioration or possible failure of a part through adverse vibration patterns. In the automotive and dynamic systems, researchers paid significant attention to measure the vibrations of moving bodies on roughness surface [7]. Elderrat have used the compression load cells sensors and displacement transducer connected with MTS software and MTS Flex Test controller for continuous data acquisition to measuring the vibrating parameters in FFFluid vibration isolators [8]; while Al-Zughaibi et al. [9] have used accelerometer sensor with MATLAB software as the measurement system to study the effects of bearing’s body friction in diminishing or removing the fluctuation of the body for quarter car test rig in cooperated with suspension system units. Both measurement systems in these studies have a possibility to record the input displacement against the output force of the test rig. Subsequently, the displacement vs force diagram could be obtained for both static and dynamic load. They have achieved acceptable results in the experimental test. Measuring the condition of things was first performed by human sense, then simple devices such as rulers were used, but nowadays measuring the parameters of a machine need complex and huge applications and consists of different components. All measurement application can be divided into three main tasks; data acquisition, data processing, and data distribution [10]. These processes are shown in Fig. 1. The term ‘data acquisition’ is used for elements which obtain information or signals relating to the quantity of a parameter being measured. The term ‘data processing’ is used for elements that amplify or reduce data and then digitalize making it ready to be accepted by a Misurata University is concerned in the equipment of experimental labs, different 44 Elderrat et al.; JERR, 15(2): 43-50, 2020; Article no.JERR.59516 modern phase, where the hardware and software are integrated into the measurement system. A virtual instrument is defined as a layer of software and hardware added to a generalpurpose computer that users can interact with the computer as though it were their own custom-designed traditional electronic instrument [11]. This phase is considered much convenience one in the structures dynamic systems and it is used in highly technical areas, such as biomedical [11]. Hence, such instrumentation is used in this study. computer. ‘Data distribution’ is where the data is displayed, recorded or transmitted to some control system. As with any modern science, instrumentation systems improved quickly during the last century. The development period had been divided into four phases [11]. The first period uses analog measurement devices. It is represented by pure analogue system devices, for example, oscilloscopes, which consist of power supply, sensors, translators, and screen displays. This system was completely closed, so they needed a manual setting. Data acquisition and processing devices are part of the second phase. In this phase, the measurement system was incorporated with a control system such as an array or Proportional–integral–derivative (PID) controller. The third phase is digital processing, where the measurement system becomes computer based and needed to digitalize the signal to convey to a computer. This stage also begins using interfaces to communicate between instruments and computers and includes the rapid development of measurement methods and tools, especially of those that are computerbased or assisted. The last phase is the distributed virtual instrumentation. It is the most 3. DESIGN OF THE INSTRUMENTATION MEASUREMENT The lab vibration unit consists of a cantilever beam fixed at one end and a suspended with a spring at the other end. An exciter (vibrating force) is placed at the middle of the beam, as shown in Fig. 2-a. The unit has been designed to add shock absorbers and remove them as needed, as shown in Fig. 2-b. To carry out experimental dynamic investigations, it is important to measure the amplitudes of the vibrating beams and to establish virtual instrumentation for such unit. Fig. 1. Elements of the measurement system (a) (b) Fig. 2. Vibration unit lab: (a) Single beam, (b) Beam with shock absorber 45 Elderrat et al.; JERR, 15(2): 43-50, 2020;; Article no.JERR.59516 no. The idea of the measurement system is to use the Linear Variable Differential Transformer (LVDT)) sensor which is essentially a differential inductive sensor. The magnetic core moves through the energized windings, producing both a voltage and a phase. In other words, this sensor can sense the amplitude and convert it to electrical signal [12]. Then, the Arduino was used as a receiver for the data received by LVDT to be digitalized. After that, this data is sent to a computer to be processed by using the Arduino IDE program and viewed by using the LABVIEW program. Fig. 3 shows the network connecting he parts of the measurement system. the mathematical equation, which describes the calibration curve, is also found. This equation used the data (the electrical signal) coming from the sensor. Fig. 5 shows the code written on the Arduino IDE program for reading the signall of LVDT and displaying the results on the screen, taking into consideration the writing of the calibration equation to obtain reliable results. In addition, LABVIEW is used to display the measurement results. Hence, the program of LABVIEW is designed for results demonstration. The instrumentation system connected with the vibration unit lab is showing in Fig. 6. 4. THEORETICAL CALCULATIONS By establishing the measurement system and connecting it with the vibration unit lab, it is important to validate its results. This unit aims to find the natural frequency of the system and to determine the mass added to a shock absorber that minimizes the amplitude of vibration beam experimentally. Therefore, it is vital to calculate these parameters theoretically to compare between the experimental and theoretical results. Fig. 3. Elements connection ction of the measurement system To calculate the natural frequency of the unit that a, it is important was previously shown in Fig. 2-a, to find the equivalent mass and stiffness element of the system. The beam is made from steel, with young's modulus = 210 / and has a width = 25 , height ℎ = 12 , and length = 838 . The stiffness of the cantilever beam is can be calculated as in [10]: After connecting the elements of the measurement system, the calibration process is an essential activity. Therefore, LVDT is calibrated to ensure that it sends signals with the same amount of the changes in displacement and has zero displacement (from stable position) at zero voltage. Fig. 4 shows the relationship between the output signal of LVDT and the ment. The third-order changes of displacement. third = Fig. 4. Calibration of LVTD 46 = ∗ ( ∗ ) = 3.85 / (1) Elderrat et al.; JERR, 15(2): 43-50, 2020; Article no.JERR.59516 Fig. 5. Code of arduino IDE Fig. 6. Instrumentation system connected with the vibration unit lab 5. EXPERIMENTAL RESULTS This beam is connected in parallel with the spring. Therefore, equivalent stiffness of all system is = 6.56 / . The mass of exciter = 4.607 , while the mass of the (vibrator) is = 2.097 . So, the total equivalent beam is = 6.704 . mass at the middle system is Hence, the natural frequency of the system is: = = . . / = 31.29 ( / ) = 298.8 The working mechanism of the measurement system and its connection with the vibration device located in the laboratory, is showing in Fig. 6. The procedures of the test were as the following: the vibration force with frequency of 100 rpm was applied to the beam; then the amplitude was recorded. Subsequently, this procedure is repeated several times with increasing the frequency by 20 rpm at each time. (2) 47 Elderrat et al.; JERR, 15(2): 43-50, 2020;; Article no.JERR.59516 no. Thus, the relationship between frequency frequ and amplitude is plotted. After that, the shock absorber was installed and repeating the previous procedures. 4018.83 / . The natural frequency from Fig. 7 = 298.8 RPM.Therefore, to find the attached mass to the shock absorber, it’s should be: = To find the natural frequency experimentally, Fig. frequ 7 shows the relationship between the frequency and amplitude. The maximum amplitude of the beam occurs when the frequency of force is equal to the natural frequency of the beam [13]. Hence, from Fig. 8, the natural frequency of the system is 300 rpm, which is close to the theoretical results 298.8 rpm (Equation 2). ∗ ( ∗ / ) . = 2.009 / . . ) ( / / ) = 4.5 (4) For validation, the experiment was repeated by using different types of beams, and the results of rimental data matched with the the experimental theoretical calculations. Fig. 9 shows the result of the experimental procedure of one of these beams. The natural frequency of such beam is 185 rpm. This beam has the following = 210 / specification: Young's modulus: , Width = 12.5 , height ℎ = 6 , length = 1048 . Thus, its natural frequency from the theoretical calculations is 200 rpm. Therefore, such instrumentation has a trustworthy result and it could be used for further experiments. The absorber has the following specification: = 210 / and the width = 25 , the . The length = 590 and height ℎ = 3.4 beam is fixed at the middle; hence it acts as dual r. Therefore, the stiffness constant of cantilever. single one is: = ( To check the calculated mass of the shock absorber in Equation 4, the minimum amplitude should have occurred at the natural frequency of the system when the shock absorber is installed. Fig. 8 shows the relationship between the frequency and amplitude of the system with shock absorber. From this figure, it is clear that mum value in the the amplitude has minimum frequency range between 280 and 320 rpm. Therefore, the mass 4.5kg is an appropriate mass for designing the correct shock absorber. The test device has been designed to add shock absorbers if needed, to design the shock absorber properly as shown in Fig. 2-b. 2 The natural frequency of the system with shock absorber should be equal or close to the natural frequency of the system without the shock absorber (Fig. 2-b,a). = = (3) The total stiffness of the shock absorber is ] = 4.018 / = 2 ∗ [2.009 / = Fig. 7. Spe Speed vs amplitude for single beam 48 Elderrat et al.; JERR, 15(2): 43-50, 2020;; Article no.JERR.59516 no. Fig. 8. Speed vs amplitude for a beam with shock absorber Fig. Fig 9. The result of the new beam 6. CONCLUSION be designed. The recorded results from the established system have proved and validated with the calculated theoretical results. Thus, the unit is ready to conduct laboratory experiments on the concept of mechanical vibration. The measurement system is an essential activity in the vibrating and structures dynamics to avoid failure of breakdown. In this study, the main objective was to establish a vibration measurement system for laboratory vibration unit. The vibration measurement measureme was successively achieved by using virtual instrumentation system. Such system consists of: LVTD sensor, Arduino microcontroller, Arduino IDE program and LabVIEW software. The established measurement system is able to precisely calculate the amplitude of the vibrating beam, so the natural frequency of the system could be determined. Also shock absorber could COMPETING INTERESTS Authors have interests exist. declared that no competing REFERENCES 1. 49 Collacott R. Mechanical fault diagnosis and condition monitoring springer science & business media; 2012. Elderrat et al.; JERR, 15(2): 43-50, 2020; Article no.JERR.59516 2. 3. 4. 5. 6. Childs PRN. 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Publishing as Prentice Hall, USA. 2011:4. © 2020 Elderrat et al.; This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Peer-review history: The peer review history for this paper can be accessed here: http://www.sdiarticle4.com/review-history/59516 50