NI LabVIEW Research Articles

Fabricating and controlling PCL electrospun microfibers using filament feeding melt electrospinning technique

The process of melt electrospinning has received noteworthy attention due to its ability to fabricate micro scaled polymer fibers. Recently, a melt electrospinning process has been attracting attention for biomedical applications, in particular with scaffold fabrication for tissue engineering. In order to enhance cell attachment and proliferation on scaffolds, it is important to control fiber diameters to create an environment to which cells can attach, grow, and proliferate with ease. However, because electrospinning is a process with many parameters, it is particularly difficult to precisely control the diameter of the resulting fibers. Also, polymer powders or pellets melted in nozzles are typically used for melt electrospinning. However, a filament feeding melt electrospinning process has not been yet been implemented. In this study, we developed a melt electrospinning device which can feed PCL (Polycaprolactone, Mw: 80 000 g mol−1) filaments for advanced electrospun fiber diameter control. The PCL filaments were first fabricated by a small scale micro-compounder and then fed into the melting chamber of the electrospinning device. The system was then heated to a desired temperature, and the melt was extruded through a nozzle. The potential difference between the nozzle and counter electrode then drew down the PCL extrudate, creating fine microfibers. Temperature was controlled and monitored via a customized temperature control system. In order to control the dispensing of the PCL filaments, a customized control algorithm using NI (National Instruments) LabVIEW was used. In order to actively cool PCL filaments, a miniature computer fan was attached on the side of the melting chamber so that the filaments would not buckle. This paper reveals the investigation of significant process parameters that influence fiber diameters and their optimization. For instance, applied voltages, distances between the nozzle and a counter electrode, processing temperatures, and polymer resin flowrates were varied. We also studied and summarized the effect of duty cycle—a ratio of forward and backward motions of the filament within a cycle time—for advanced fiber diameter control. Moreover, the relationship between a flow rate and a duty cycle and their influences on a fiber diameter were studied.

Water Quality Monitoring with Fuzzy Logic Control based on Graphical Programming

Water quality is the most important aspect to ensure success in various aspects of life, for example in the shrimp ponds. On a shrimp pond, water conditions are very vital because it has a very strict threshold. Unstable water conditions will affect growth and condition of shrimps, eat passion of shrimps, until their ability to survive greatly affect the survival of the shrimps. The percentage of farmers harvesting shrimps if the water did not have good conditions then the farmers will suffer significant losses if yields were not as expected, began from the amount of shrimp that was reduced due to death or the quality of the shrimp were judged from the size of the shrimp. So the authors wanted to do research on how to maintain the quality of the water in shrimp pond so that the water quality is maintained. To overcome this, we need to monitor water conditions based on the level of salinity and turbidity of water in order to stay in good condition. In this case, the researchers used fuzzy logic to monitor the amount of water quality and water volume. In this study only conducted water quality monitoring process but to do water changes to a certain condition still conducted manually. As well as the programming language used as the NI LabVIEW graphical programming with the application form to see monitoring of water quality so that water conditions are well preserved.

Discrete wavelet packet transform based controller for liquid level system and its performance analysis

Abstract A new controller based on discrete wavelet packet transform (DWPT) for liquid level system (LLS) has been presented here. In this proposed controller, packet transform is used to decompose the error signal into different frequency nodes at various scales which represents many underlying phenomena such as process dynamics, noise and disturbances. These coefficients are scaled by their respective gains and then added together to generate the control signal. NI DAQ device is used to interface between the PC based controllers simulated in NI LABVIEW software to the real time RC plant analogous to LLS and a second order RLC plant. The performance of this controller has been studied and compared to the PI controller. From hardware results, this controller is shown to perform better than both the discrete wavelet transform (DWT) based proportional integral controller and PI controller. Also, it can handle noise more efficiently.

Sensitive detection of oxygen using a diffused integrating cavity as a gas absorption cell

In this study, an oxygen monitoring system was demonstrated for sensitive oxygen detection. The system is based on tunable diode laser absorption spectroscopy (TDLAS) and wavelength modulation spectroscopy (WMS). Stable 2nd-harmonic signals of oxygen were detected by measuring the oxygen P9 absorption line at 764.38nm. In the detection, a cubic diffuse integrating cavity was employed as a gas absorption cell to increase the optical path length and achieve a higher sensitivity. In addition, to perform automatic gas concentration measurements, a data recording and analyzing program based on the National Instruments LabVIEW software platform was developed. An uncertainty of 0.05% and a detection sensitivity of 350 ppmv were obtained using this system.

An experimental investigation of vibration characteristics of compression ignition engine running with neem methyl ester

Reduction of fossil fuel reserves, environmental deterioration, global warming, and rigorous emission norms have necessitated the need for alternate fuel such as biodiesels. Diesel engines produce a higher vibration which leads to a reduced engine life span. In the present study, the vibration of a compression ignition engine has been measured for both diesel and Neem methyl ester. The experiments were carried out at 0%, 25%, 50%, 75%, and 100% load when the engine runs at a constant speed of 1500 rpm and with a compression ratio of 16. Triaxial accelerometer is used for measuring engine vibration along vertical, lateral, and longitudinal directions. Data acquisition and analysis are obtained by NI LabVIEW. It has been observed that an engine running with NME produces lower combustion induced vibration acceleration compared to diesel fuel. It is also noticed that higher peak amplitudes are observed at the frequency of 25 Hz for both diesel and NME, within the range of 0–100 Hz and along three directions. Within the range of 100–3000 Hz, the highest peak amplitudes are observed for engine running with diesel compared to neem methyl ester. At a 100% load, the change in vibration amplitude is 64.94 %, 86.41%, and 17% along vertical, lateral, and longitudinal directions when fuel is changed from NME to diesel. Combustion characteristics such as maximum cylinder pressure, heat release rate, and rate of pressure rise are also measured for both diesel and NME in order to find the relationship between combustion and vibration. At full load conditions, the maximum combustion pressure and maximum rate of pressure rise are increased by 2.1% and 8.33% with pure diesel compared to neem methyl ester. The experimental work suggests that neem methyl ester can be directly used in diesel engines in view of a lesser engine vibration and higher engine life.

Force and Flow Field Measurement System for Tandem Flapping Wings

A test rig is developed to investigate the force and flow field characteristics of tandem flapping wings. The setup comprises a low Reynolds number recirculating water tunnel, two sets of plunge and pitch motion rigs, and a force and flow field acquisition system. A program for the motion and data acquisition is developed based on the NI LabVIEW platform. The water tunnel mainly consists of a water tank, a contraction section, a test section, and a centrifugal pump system. Many kinematic parameters of the tandem flapping motion can be adjusted in our developed test rig. These parameters are the phase angle between flapping motions of the forewing and hindwing, as well as the spacing distance, flapping frequency, and amplitude of the forewing and hindwing. The prominent feature of the motion rigs is that the phase angle can be adjusted continuously from 0 to 360°. The thrust and lift on the flapping wing are measured by a three-dimensional force sensor. A square wave produced by the program is used to identify the start of the flapping motion. The flow field around the flapping wing can be captured by a digital particle image velocimetry (DPIV) at the desired phases of the motion because the DPIV can be triggered by a square wave at any time within a cycle. The boundary of a vortex is determined according to the λ2-criterion with DPIV measurement data, and then its circulation can be computed.

Development of a set of structural acoustic teaching demonstrations using a simply supported rectangular plate

As part of the Sound-Structure Interaction course, offered through the Penn State Graduate Program in Acoustics, a set of demonstrations was developed to help reinforce structural acoustics theory. A common test article, a simply supported plate, was developed for a set of four demonstrations. The simply supported plate was used to demonstrate the concepts of mobility functions, radiated sound directivity, fluid loading and acoustic transmission loss. A modal impact hammer, accelerometers, microphones, a sound level meter and a sound intensity probe were used in combination with National Instruments compact DAQ systems and LabVIEW software to develop these custom demonstrations. Basic theory and setup of the demonstrations are presented as well as links to the videos of the demonstrations themselves.

FPGA based Signal Generation using LabVIEW software

In this paper there is a study on the FPGA, its advantages and disadvantages and an application based on FPGA using software and hardware. Now-a-days FPGA has been widely used in industrial and commercial fields. In domestic purpose FPGA is also used in our day to day life. FPGAs used in software makes thing easier and simpler when the program is dumped into the hardware. FPGA is considered to be dynamic, robust, and flexible which can be easily reconfigurable and can run in real time. The paper also includes an application which generates signal for basic communication purposes. The software includes NI LabVIEW and NI PXIe 1075 as hardware. By the effective use of this application we can apply this in various fields like digital communications, military and defence area for communication as well as security purpose.

PXIe based data acquisition and control system for ECRH systems on SST-1 and Aditya tokamak

In Steady State Superconducting (SST-1) tokamak, various RF heating sub-systems are used for plasma heating experiments. In SST-1, Two Electron Cyclotron Resonance Heating (ECRH) systems have been installed for pre-ionization, heating and current drive experiments. The 42GHz gyrotron based ECRH system is installed and in operation with SST-1 plasma experiments. The 82.6GHz gyrotron delivers 200kW CW power (1000s) while the 42GHz gyrotron delivers 500kW power for 500ms duration. Each gyrotron system consists of various auxiliary power supplies, the crowbar unit and the water cooling system. The PXIe (PCI bus extension for Instrumentation Express)bus based DAC (Data Acquisition and Control) system has been designed, developed and under implementation for safe and reliable operation of the gyrotron. The Control and Monitoring Software applications have been developed using NI LabView 2014 software with real time support on windows platform.

A New, Scalable and Low Cost Multi-Channel Monitoring System for Polymer Electrolyte Fuel Cells.

In this work a new, scalable and low cost multi-channel monitoring system for Polymer Electrolyte Fuel Cells (PEFCs) has been designed, constructed and experimentally validated. This developed monitoring system performs non-intrusive voltage measurement of each individual cell of a PEFC stack and it is scalable, in the sense that it is capable to carry out measurements in stacks from 1 to 120 cells (from watts to kilowatts). The developed system comprises two main subsystems: hardware devoted to data acquisition (DAQ) and software devoted to real-time monitoring. The DAQ subsystem is based on the low-cost open-source platform Arduino and the real-time monitoring subsystem has been developed using the high-level graphical language NI LabVIEW. Such integration can be considered a novelty in scientific literature for PEFC monitoring systems. An original amplifying and multiplexing board has been designed to increase the Arduino input port availability. Data storage and real-time monitoring have been performed with an easy-to-use interface. Graphical and numerical visualization allows a continuous tracking of cell voltage. Scalability, flexibility, easy-to-use, versatility and low cost are the main features of the proposed approach. The system is described and experimental results are presented. These results demonstrate its suitability to monitor the voltage in a PEFC at cell level.

Algorythm of out-of-band radiation reduction

The paper represents regular method of synthesis of a bit signal for the wireless communication networks using frequency manipulation for coding of the transferred information. The synthesized signal has two-level envelope and low sidelobe level in the set area of a spectrum. The synthesis method is based on repeated operations of a delay and addition of initial sequence of pulses with rectangular envelope. As a result of synthesis the signal with pulse-width modulation is obtained. Software implementation of the algorithm was created using development environment NI LabVIEW. Temporal and spectral properties of the signal are researched. The signal can also find application in Doppler's ultrasonic systems that use high-powered nonlinear amplifiers.

Development of a field-based high-throughput mobile phenotyping platform

In this study, a mobile, field-based, high-throughput phenotyping platform was developed for rapid measurement of plant characteristics. The platform consisted of three sets of sensors mounted on a high-clearance vehicle. Each set contained two infrared thermometers (IRT), one ultrasonic sensor, one Crop Circle multi-spectral crop canopy sensor, and one GreenSeeker crop sensing system. Each sensor set measured canopy temperature, crop height, and canopy spectral reflectance of a plant plot. Thus, three plots were measured simultaneously in a single pass. In addition to the sensors, the platform was equipped with a laser distance sensor to measure the height of the sensor beam and an RTK-GPS system that provided precise, accurate position data for georeferencing sensor measurements. Software for collecting, georeferencing, and logging sensor data was developed using National Instruments LabVIEW on a laptop computer. The hardware and software design was modular, allowing easy addition and removal of sensors and flexible system expansion. The fast sampling rates for sensors allowed the phenotyper to operate in field at a ground speed of 3.2km/h. Two verification tests were conducted to evaluate the phenotyping system. In the first test, data timestamps were analyzed to determine if the system could collect data at the required rates and if the time delays would cause significant position errors. Test results showed that data from all sensors were received within the desirable time frame and the largest position error was 17.9cm when the phenotyper was moving at a speed of 3.2km/h. The position errors can be corrected during data post processing. The second test determined whether changes in ambient light and ambient temperature had statistically significant effects on the accuracy of the sensor measurements. For the IRT sensors, a correction method using ground truth temperature measurement made during two periods within a day was recommended to correct the errors in surface temperature measured by the IRTs.

Neuro-fuzzy-based smart DSS for crop specific irrigation control and SMS notification generation for precision agriculture

A feed forward neural network and fuzzy logic-based hybrid smart decision support system (DSS) for crop specific irrigation notification and control in precision agriculture (PA) is proposed in this paper. This proposed neuro-fuzzy smart DSS can be implemented in any farm land, green-house and poly-house for efficient irrigation management and control for PA. A feed forward neural network is trained and linear regression is performed to predict soil moisture content (MC) in hourly basis. The predicted soil MC is utilised by fuzzy logic-based smart DSS model to produce SMS notification to the farmer. The proposed DSS model can work on real-time mode using National Instruments LabVIEW. This hybrid smart DSS prediction algorithm is implemented using data group of 24 cases measured in the farming land located in Bhubaneswar, the southern part of India. Crop wise evapotranspiration is also calculated using Blaney-Criddle method to notify the farmers via SMS service.

PWM Algorithms Synthesis

The paper describes various modified algorithms of classical sinusoidal pulse width modulation (PWM) serving for a three-phase two-level inverter control. The paper presents the results of a research of 3 PWM versions with varying duty cycle parameters and frequency of the pulse signal modulation. The method is to divide the modulated sinusoidal signal cycle (half-cycle) into intervals in order to change the modulation frequency within the separate sectors of forming the quasi-sinusoidal output voltage waves. In addition, algorithmic ways to compensate the additional losses in the inverter and the induction motor at high modulation frequencies of a discrete control signal are investigated and described in the paper. Calculations and simulations are performed by NI Multisim simulation program and NI LabVIEW visual programming environment. Theoretical studies are performed using the electric drive theories, discrete control systems and spectral analysis. The practical implementation performed by Texas Instruments Stellaris Launchpad using the Energia prototyping platform, field-programmable gate arrays (FPGA) of National Instruments CompactRIO-9074 and NI Single-Board RIO GPIC (sbRIO-9606, NI 9683 (GPIC), LX45 FPGA) using NI LabVIEW software and add-on modules (LabVIEW Real Time, LabVIEW FPGA). The suggested inverter control methods make it possible to reduce the distortion of the output quasi-sinusoidal signal and reduce the power consumption of the DC link while significantly reducing the number of inverter transistor switching in comparison with the classical method without premodulation or technical devices (filter-compensating devices).

Testing System for Analog Devices Direct Digital Synthesizer

The paper is devoted to the setup for controlling and testing of Direct Digital Synthesizer (DDS) Integrated Circuits (ICs). Control and measurement setup is designed on the basis of National Instruments module equipment PXI-4110, PXI-7841R and LabVIEW development environment. Block diagram of the developed system and software structure are depicted as well as test results for several ICs.

基于Labview的高速数据采集与存储系统的设计

针对市面上现有的一般的数据采集卡采样位数不高和采样内存不够，从而不能进行长时间对信号进行有效的连续采样等问题。本文设计了基于labview的高速数据采集和存储系统。该系统能够实现高精度、高数据率，还可以采用软件和硬件同步触发的方式来完成对周期信号进行多通道连续实时监测采集和存储，使数据采集存储系统的采样内存扩展至电脑的内存。本系统以NI公司的高速数据采集卡为基础，以labview 2012为上位机软件开发平台，由数据采集卡对周期信号进行数据采集再通过串口将采集到的数据上传到上位机，上位机对采集的数据进行存储、显示和分析实现了多通道模拟量的实时监测。该设计最终实现了采样通道数为2，采样速率为200 M/s，采样精度为12位，采样深度达到2000。平台有效性验证了该采集平台兼容性好、性能稳定采集信号误差小，能够尽量做到对实际信号源数据的无失真还原。本文为高速数据采集提供了一种便携的设计方案，可以广泛的应用到现代测试测量技术工程中。 In view of the existing general data acquisition card in the market, it is not enough to have high sampling and sampling memory, so that the acquisition system cannot be carried out for a long time. The design of high speed data acquisition and storage system is based on Labview. It can not only achieve high accuracy and high data rate but also use the software and hardware synchronization trigger to complete the multi-channel continuous real-time monitoring of the acquisition and storage of periodic signal which is similar to the function of the oscilloscope. This system is based on high speed data acquisition card of NI company and Labview 2012 for PC software development platform. Data acquisition card is used for data acquisition of periodic signal through the serial port and collect data upload to upper computer. Upper computer collects data for storage, display and analysis to realize the real-time monitoring of mul-ti-channel analog. The design of the sampling channel is 2, the sampling rate up to 200 M/s, the sampling precision is 12, and the sampling depth is 2000. Platform validation of the collection platform has good compatibility, performance and stability of the collection signal error is ignorable, which can be as far as possible to the actual signal source data without distortion reduction. This paper provides a portable design for high speed data acquisition, which can be widely used in the engineering of modern test and measurement technology.

Automated Data Processing System for Oscilloscope Measurements during an Environmental Test

The paper discusses the automation of the processing of images obtained with an oscilloscope using National Instruments LabVIEW software. The mathematical background is presented as well as standard hardware communication interface. The block diagram of the electrical signal acquisition and processing system and the front panel with an example of processed waveforms is shown in the paper.

Development of a Desktop Hybrid Multipurpose Grinding and 3D Printing Machine for Educational Purposes

Manufacturing is a constantly changing field where new innovations and continuous improvements ensure competitiveness. Recent manufacturing revolutions include additive manufacturing and the empowerment of Do It Yourself (DIY) users. This paper reports on the development of a desktop hybrid machine that incorporates subtractive and additive manufacturing principles, in particular grinding and wire extrusion. Due to the small machine size of less than 1 m3 and use of modular components it will be applicable in small scale operations and will have a low energy footprint. The article discusses the initial design and further improvements which have been done as senior design capstone projects, through summer internships and team work of graduate and undergraduate students. The first generation machine will be improved by stronger motor modules of up to 1.8Nm torque compared to 0.7Nm and new module connections that can be 3D printed instead of sheet metal connections. Future versions of the machine will have even more printable components. The machine control has been built on NI LabVIEW to enable path planning, machine control, manual steering, and integration of closed-loop algorithms on one standard platform.

An intelligent technique for condition based self-maintenance of aluminum electrolytic capacitors

This paper presents an intelligent technique for condition based self-maintenance of aluminum electrolytic capacitors. In-circuit condition of capacitors is monitored by calculating its remaining useful life in real time. On the basis of capacitor condition, self-maintained operation is performed by controlling the case temperature using thermo-electric cooling (TEC) module. Temperature difference between two plates of TEC module is obtained by varying duty ratio of its input voltage waveform that is capacitor case temperature dependent. Temperature of capacitor is controlled by maintaining cold side temperature of TEC as function of change in case to ambient temperature. The proposed scheme is implemented in National Instruments LabVIEW software and a low cost microcontroller board is used for data acquisition and control. To make the developed system more flexible in use, it has two different modes of operation: monitoring mode and self-maintenance mode. There are provisions for auto shut down of test circuit at critical condition of capacitor and also manual shut down for maintenance or other purposes. The scheme is equipped with web based remote monitoring and maintenance feature. The proposed technique can be customized for condition monitoring and maintenance of critical components in any power electronic system.

A Nonlinear Friction Model for an Electromechanical Actuator Valve

In this work we have extended a basic linear model of the Electromechanical Throttle Valve to a nonlinear friction model, which captures the most important friction phenomenon of interest for fault detection. In our examination we have implemented the Tustin’s friction model. This nonlinear friction model has only 4 parameters but describes the friction phenomenon of the Stribeck effect also it includes both the Stick and Slip regimes. To the validation of the actuator model and examination of the friction models we have performed experiments using the experimental setup of NI LabVIEW CompactRIO. The friction phenomenon as hysteresis, stick-slip and Stribeck effects, are an interest for fault detection of the Actuator Valve. The experimental results have shown, that Tustin’s model provides a good approach for modeling of the friction behaviour of the Electromechanical Throttle Valve.