Dynamic Signal Analyzer Research Articles

DSP‐based resolver‐to‐digital conversion system designed in time domain

Resolver is an absolute angle measurement and is mounted on the motor shaft to acquire the motor's absolute angular position. This study presents an equivalent circuit of the resolver neglected rotational back electromotive force. The transfer function of the resolver is derived from the equivalent circuit. The frequency response of the resolver is measured by a dynamic signal analyser to obtain the adequate frequency of resolver's reference signal. Furthermore, a digital signal processor (DSP)-based resolver-to-digital conversion system is designed in time domain. A pulse signal generated by the DSP is utilised as a reference signal coupled into the resolver's rotor winding and provides primary excitation. The sine and cosine modulated output signals are sampled by the analogue-to-digital converter of the DSP within 1 μs. The sampled frequency of outputs signals are the same frequency as the pulse signal. The angular position is derived by the inverse tangent of the quotient of the demodulated sine and cosine samples. Test results are presented to validate the performances of the proposed scheme.

LabVIEWⓇ기반 6축 수직다관절 로봇의 게인스케쥴링 구현 연구

Recent years have witnessed a growing demand for a wide variety of high-performance industrial robots. In this paper, for accurate gain tuning of a 6-axis articulated industrial robot with reduced noise, a program routine for a dynamic signal analyzer (DSA) using the frequency response method will be programmed using <TEX>$LabVIEW^{(R)}$</TEX>. Then, robot transfer functions can be obtained experimentally using the frequency response method with the DSA program. Data from the robot transfer functions are transformed into Bode plots, based on which an optimal gain tuning will be executed. Gain tuning can enhance the response quality of the output signal for a given input signal during real-time control of the robot. The effectiveness of our proposed technique will be verified by implementation with a (lab-manufactured) 6-axis articulated industrial robot (hereinafter called "RS2") and comparison with the zero position gain tuning, as well as other positions.

The hydraulic mechanism of the unfolding of hind wings in Dorcus titanus platymelus (order: Coleoptera).

In most beetles, the hind wings are thin and fragile; when at rest, they are held over the back of the beetle. When the hind wing unfolds, it provides the necessary aerodynamic forces for flight. In this paper, we investigate the hydraulic mechanism of the unfolding process of the hind wings in Dorcus titanus platymelus (Oder: Coleoptera). The wing unfolding process of Dorcus titanus platymelus was examined using high speed camera sequences (400 frames/s), and the hydraulic pressure in the veins was measured with a biological pressure sensor and dynamic signal acquisition and analysis (DSA) during the expansion process. We found that the total time for the release of hydraulic pressure during wing folding is longer than the time required for unfolding. The pressure is proportional to the length of the wings and the body mass of the beetle. A retinal camera was used to investigate the fluid direction. We found that the peak pressures correspond to two main cross-folding joint expansions in the hind wing. These observations strongly suggest that blood pressure facilitates the extension of hind wings during unfolding.

Dynamic Faraday cup signal analysis and the measurement of energetic ions emitted by plasma focus

A theoretical model is developed to study the signals from a typical dynamic Faraday cup, and using this model the output signals from this structure are obtained. A detailed discussion on the signal structure, using different experimental conditions, is also given. It is argued that there is a possibility of determining the total charge of the generated ion pulse, the maximum velocity of the ions, ion velocity distribution, and the number of ion species for mixed working gases, under certain conditions. In addition, the number of different ionization stages, the number of different pinches in one shot, and the number of different existing acceleration mechanisms can also be determined provided that the mentioned conditions being satisfied. An experiment is carried out on the Filippov type 90 kJ Sahand plasma focus using Ar as the working gas at the pressure of 0.25 Torr. The data from a typical shot are fitted to a signal from the model and the total charge of the related energetic ion pulse is deduced using the values of the obtained fit parameters. Good agreement between the obtained amount of the total charge and the values obtained during other experiments on the same plasma focus device is observed.

An in vitro Model of a System of Electrical Potential Compensation in Extracorporeal Circulation

Extracorporeal circulation (ECC) in patients undergoing cardiac surgery induces systemic immune-inflammatory reaction that results in increased postoperative morbidity. Many factors are responsible for the adverse response after ECC. The present in vitro study aimed to investigate electric charges (ECs) generated during ECC, to set a device compensating the ECs, and checking its effect on red blood cells (RBC). The electrical signals of blood in ECC were collected by a custom developed low-noise electronic circuit, processed by a digital oscilloscope (DSO) and a dynamic signal analyzer (DSA). The compensation of ECs was performed using a compensation device, injecting a nulling charge into the blood circuit. The compensation effect of the ECs on RBCs was evaluated by scanning electron microscope (SEM). The electrical analysis performed using both the DSO and the DSA confirmed the EC formation during ECC. The notable electric signals recorded in standard ECC circuits substantially nulled once the compensation device was used, thus confirming efficient EC compensation. After two hours of ECC, the SEM non-blended test on human RBC samples highlighted morphological changes in acanthocytes of the normal biconcave-shaped RBC. The outcomes confirm the development of parasitic ECs during ECC and that a suppressor system may decrease the potential damage of ECs. Nevertheless, further studies are ongoing in order to investigate the complex mechanisms related to lymphocytes and platelet morphological and physiological chances during triboelectric charges in ECC.

Mechanism of electro-hydraulic exciter for new tamping device

A new tamping device which is driven by an electrohydraulic exciter was proposed to overcome the limitations of mechanically driven devices. The double-rod oscillation cylinder drives the tamping arm to realize vibration. A new spin valve was designed in order to fulfill dynamic state requirements of the oscillation cylinder. Parametric analysis was carried out by establishing mathematic model. Then, the relationships among the structure of valve port and the frequency, amplitude, output shock force of the cylinder were researched. An experimental device of the electrohydraulic exciter was established to validate the theoretical results. The signals were acquired by AVANT dynamic signal analyser of vibration. The results show that new tamping device can satisfy all kinds of complex working conditions with the flexible adjustment of frequency and amplitude.

A Current-Controlled PCB Integrated MEMS Tilt Mirror

Introduction: MEMS Tilt Mirror - a miniature planar micro-mirror that can experience a 1-D or 2-D tilt in response to a control signal. Commonly used technologies- electrostatic, piezoelectric, electrothermal bimorph. Applications - laser beam steering, interferometers, dynamic signal analyzers, opticcal cross-connect switches. This paper describes the design, key features and applications of a System On Chip (SOC) ASIC (Application Specific Integrated Circuit) that has been developed under an Air Force SBIR program. The SOC device has been implemented by Honeywell International using their High Temperature SOI (Silicon On Insulator) Process. The objective of the Air Force SBIR program {1} was to investigate the potential for use of available High Temperature SOI technology devices for aerospace propulsion control system applications. Several prototype designs implemented by Embedded Systems LLC (ES-LLC) using available SOI devices identified significant limitations in the performance capability and level of integration. The diversity of propulsion system interfacing requirements demanded generic solutions so that they could be deployed in multiple applications without changes. The available devices were also not affordable due to the limited size of the market for this technology. It was therefore decided to develop a generic, reconfigurable SOC chipset {2} that could be implemented using Honeywell's HT200 Family of ASIC Gate Arrays. The paper will describe the architecture and key features of the SOC chipset solution which can be reconfigured to interface with most typical aerospace control system sensors and actuators. The SOC chipset captures all of the necessary functions required to interface with sensors such as RTD (resistance Temperature Detectors), Strain Gauges (SG) and thermocouples (TC), mass flow, speed and LVDT (Linear Variable Differential Transducer) position. The excitation circuitry required to power these interfaces is embedded in the chipset and can be reconfigured as required. The SOC chipset also contains all of the pre- and post-processing functions to convert electrical signals into digital words and send them on a data bus under the control of a host microprocessor. The SOC chipset can be powered from a Mil-Std 704F compliant power source or a conditioned DC power source. The SOC chipset when combined with other external devices can be implemented as a “Smart Node” for localized management of sensors and actuators as a part of a distributed architecture or used as a scalable building block in a more complex function such as a FADEC (Full Authority Digital Engine Control). The SOC chipset thus completes the set of all High Temperature SOI Integrated circuits required for implementation of typical Smart Nodes. It is believed that the versatility of the SOC chipset makes it a well suited, affordable, scalable building block for not only aerospace controls but also for diverse applications such as down-hole drilling, energy exploration, wind farms etc. where high temperature electronics is required.

Narrowband low frequency pressure and vibration inside homes in the proximity to wind farms

Narrowband fast Fourier transform measurements made outside and inside homes indicate that unlike audible tones, low frequency pressure waves penetrate homes virtually un-attenuated. Simultaneous multi-channel linear weighted pressure measurements were made in various locations as well as seismic floor velocities using various dynamic signal analyzers and sensors. Several areas of concern would include harmonics of blade pass frequencies and also modulation at 20, 30, and 40 Hz (audible). Traditional acoustic models do not predict or measure low frequencies as raw un-weighted pressure. Measurements to be presented indicate pressure levels much higher than the audible tone pressure levels. Similar signatures were measured as seismic ground vibration in the basements of homes at relatively low levels. In order to minimize the effects in the homes and to locate wind turbines properly, it may be important to establish measurement standards for low frequencies before locating wind turbine developments.

Quantitative EEG analysis using error reduction ratio-causality test; validation on simulated and real EEG data

ObjectiveTo introduce a new method of quantitative EEG analysis in the time domain, the error reduction ratio (ERR)-causality test. To compare performance against cross-correlation and coherence with phase measures. MethodsA simulation example was used as a gold standard to assess the performance of ERR-causality, against cross-correlation and coherence. The methods were then applied to real EEG data. ResultsAnalysis of both simulated and real EEG data demonstrates that ERR-causality successfully detects dynamically evolving changes between two signals, with very high time resolution, dependent on the sampling rate of the data. Our method can properly detect both linear and non-linear effects, encountered during analysis of focal and generalised seizures. ConclusionsWe introduce a new quantitative EEG method of analysis. It detects real time levels of synchronisation in the linear and non-linear domains. It computes directionality of information flow with corresponding time lags. SignificanceThis novel dynamic real time EEG signal analysis unveils hidden neural network interactions with a very high time resolution. These interactions cannot be adequately resolved by the traditional methods of coherence and cross-correlation, which provide limited results in the presence of non-linear effects and lack fidelity for changes appearing over small periods of time.

Dynamic Response Analysis of Passive Wireless Surface Acoustic Wave (SAW) Strain Sensors Used for Force Measurement in Turning

Passive wireless surface acoustic wave (SAW) strain sensors offer significant advantages over alternative well known sensing technologies and can enable sensing applications robustly in very harsh environments. The passive wireless operation of SAW sensors is especially relevant given there is a drive for more robust and diverse sensing technologies in more complex and high performance applications. Wireless passive dynamic SAW strain sensing has been realised and has enabled force measurement during CNC turning. This paper demonstrates the SAW performance alongside two state of the art Kistler sensing technologies designed for this application area. Direct analysis and investigation of both static and dynamic signals is important for establishing bench-mark performancemetrics and the operational bandwidth of the SAW system.

Kinetics of gene derepression by ERK signaling

ERK controls gene expression in development, but mechanisms that link ERK activation to changes in transcription are not well understood. We used high-resolution analysis of signaling dynamics to study transcriptional interpretation of ERK signaling during Drosophila embryogenesis, at a stage when ERK induces transcription of intermediate neuroblasts defective (ind), a gene essential for patterning of the nerve cord. ERK induces ind by antagonizing its repression by Capicua (Cic), a transcription factor that acts as a sensor of receptor tyrosine kinases in animal development and human diseases. A recent study established that active ERK reduces the nuclear levels of Cic, but it remained unclear whether this is required for the induction of Cic target genes. We provide evidence that Cic binding sites within the regulatory DNA of ind control the spatial extent and the timing of ind expression. At the same time, we demonstrate that ERK induces ind before Cic levels in the nucleus are reduced. Based on this, we propose that ERK-dependent relief of gene repression by Cic is a two-step process, in which fast reduction of repressor activity is followed by slower changes in nuclear localization and overall protein levels. This may be a common feature of systems in which ERK induces genes by relief of transcriptional repression.

Design of Quasi-Logarithmic Multisine Excitations for Robust Broad Frequency Band Measurements

The logarithmic distribution of spectral lines in excitation signals is widely used to measure the transfer functions of dynamic systems over a wide frequency band, covering several decades. Periodic signals are very popular in many advanced dynamic signal analyzers. Generating multitone periodic signals requires an equidistant frequency grid which conflicts with the logarithmic distribution, particularly at the low frequencies. In this paper, we offer an elegant solution to get around this problem using an improved choice for the amplitude spectrum of the multitone. We also offer a simple way to tune the frequency spacing of such a signal to allow for robust identification of the system under test.

Road Pavement Stiffness Determination using SASW Method

The Spectral Analysis of Surface Waves (SASW) method is an in-situ seismic technique for the evaluation and assessment of road pavement. The method is based on the theory of stress waves propagating in elastic media with the key elements being the generation and detection of Rayleigh wave motion. A set of transient impact source with a range of frequencies is used to generate the Rayleigh wave energy that is able to propagate along the surface layer of the pavement. Through two vertical accelerometers, the motion of the wave for each range of frequency is recorded and calculated using a dynamic signal analyzer. A dispersion curve is then constructed from the cross-power spectrum of the Fast Fourier Transform (FFT) that results in the phase velocity versus wavelength plot. An iterative inversion is then carried out to obtain the shear wave velocity profile with depth and the corresponding dynamic modulus of each pavement units. This paper presents a case study carried out on a new road pavement construction site. It was found that the profile of the dynamic shear and Young’s modulus versus depth obtained from SASW method

Fault Diagnosis for Rack Vibration of Brush Roll in Washing Section of Galvanization Unit in Cold Rolling Plant by Means of HP35670A Dynamic Signal Analyzer

The paper determines the real-time location of and the real-time reasons for equipment failures on the premise of the integration of equipment, through the online detection and the real-time analysis of the vibration abnormities and faults in the driving side as well as the service side of rack of brush roll in the washing groove that lies in washing section 2# of the galvanization unit in a plant, by employing the HP35670A dynamic signal analyzer.

System Identification Using Embedded Dynamic Signal Analyzer

The effect of model uncertainty is increased in optical disc drives (ODDs) because the mechanical and electrical components are manufactured with a wide error tolerance to reduce production costs. In this paper, we introduce a new technique for system identification whereby an embedded dynamic signal analyzer (EDSA) is used for the estimation of the system frequency characteristics. The estimated transfer function can be utilized to adapt a controller and improve the performance and stability of the system in terms of the model uncertainty. The EDSA comprises a sine generator, system identifier, and band-pass filter. A design methodology is proposed for the production of an accurate and cost-effective sine signal, which minimizes error and prevents overflow. Moreover, the proposed algorithms are implemented in a system-on-chip for an ODD. The experimental results show that the EDSA exhibits good performance and reliability.

Resonance Suppression on Nanoscale Viscoelasticity Measurement

During the broadband viscoelasticity measurement process, when the frequency of the excitation force become high relative to the resonant frequency or the bandwidth of the instrument dynamics, the adverse instrument dynamics is motivated, which causes the cantilever resonance and generates large measurement errors in the measurement data. To solve this problem, an approach to suppress the cantilever resonance on the broadband viscoelasticity measurement is proposed. Firstly, Atomic force microscope (AFM) system dynamic is analyzed by using a dynamic signal analyzer (DSA) in the z-axis. And a notch filter is designed as a prefilter of the AFM system to filter the input drive voltage in order to offset the resonance peak in the AFM model. Secondly, an adaptive filter based on LMS is designed to further eliminate the residual cantilever resonance effects on the complex compliance of soft materials, referring to the Hertz contact model. Finally, the proposed approach is illustrated by implementing it to remove the cantilever resonance effects on the broadband viscoelasticity measurement of a polydimethylsiloxane (PDMS) sample using AFM.

Magnetic Resonance Perfusion of the Myocardium

The aim of this study was to investigate if a quantitative evaluation of a magnetic resonance (MR) perfusion examination of the myocardium can achieve a comparable diagnostic accuracy as a semiquantitative evaluation. A total of 31 patients with suspected coronary artery disease underwent MR imaging and conventional coronary angiography. Stenoses with a diameter reduction between 50% and 75% were evaluated by an intracoronary pressure wire examination (fractional flow reserve) for assessment of their hemodynamic relevance. A 0.05 mmol/kg contrast material bolus (gadopentetate dimeglumine) was applied during adenosine-induced stress (140 μg/kg/min) and at rest with a flow rate of 5 mL/s. Signal intensity time curves of the first-pass MR perfusion images, acquired at rest and under adenosine stress with a Saturation Recovery-turbo Fast Low Angle Shot Magnetic Resonance Imaging sequence, were analyzed by Argus Dynamic Signal Analysis (Siemens Healthcare, Erlangen, Germany). For the semiquantitative evaluation, the upslope value of a linear fit from the foot point to the signal maximum was calculated for 18 segments (signal intensity units per second). For the quantitative evaluation, a model-independent deconvolution was used to calculate coronary blood flow (MBF in mL/100 g/min). For each segment for the stress and rest examination, upslope value and MBF were determined. In addition, the ratio of the stress and rest value for each segment was determined (myocardial perfusion reserve index [MPRI]). The mean value of the 2 segments with the lowest value was calculated for each patient. Coronary artery stenosis greater than 75% or greater than 50% with positive fractional flow reserve less than 0.75 was considered as hemodynamically relevant. Receiver-operator-curves were calculated. The values of the area under the ROC curves were 0.74, 0.66, and 0.92 for the US(Stress), US(Rest), and US(MPRI) evaluations (semiquantitative evaluation). The values for the MBF(Stress), MBF(Rest), and MBF(MPRI) evaluations (quantitative evaluation) were 0.92, 0.68, and 0.84, respectively. Comparing US(MPRI) and MBF(Stress), identical values and no significant difference were found for the area under the ROC curves. A quantitative evaluation using a model-free deconvolution provides identical diagnostic performance when only a stress examination is used, much similar to a semiquantitative evaluation, if both stress and rest examinations are used.

Detection of a static eccentricity fault in a closed loop driven induction motor by using the angular domain order tracking analysis method

In this study, a new method was presented for the detection of a static eccentricity fault in a closed loop operating induction motor driven by inverter. Contrary to the motors supplied by the line, if the speed and load, and therefore the amplitude and frequency, of the current constantly change then this also causes a continuous change in the location of fault harmonics in the frequency spectrum. Angular Domain Order Tracking analysis (AD-OT) is one of the most frequently used fault diagnosis methods in the monitoring of rotating machines and the analysis of dynamic vibration signals. In the presented experimental study, motor phase current and rotor speed were monitored at various speeds and load levels with a healthy and static eccentricity fault in the closed loop driven induction motor with vector control. The AD-OT method was applied to the motor current and the results were compared with the traditional FFT and Fourier Transform based Order Tracking (FT-OT) methods. The experimental results demonstrate that AD-OT method is more efficient than the FFT and FT-OT methods for fault diagnosis, especially while the motor is operating run-up and run-down. Also the AD-OT does not incur any additional cost for the user because in inverter driven systems, current and speed sensor coexist in the system. The main innovative parts of this study are that AD-OT method was implemented on the motor current signal for the first time.

The Design of Embedded AeroEngine Measurement and Test System Based on ARM and FPGA

Present Measurement and test system for aeroengine rig testing is primarily based on DSP and PC104 industrial computer, which have the disadvantages of large volume, high power consumption, single function and less-generic. So it is a valuable job to promote the performance of the system employing the latest methods of collaborative design and embedded hardware and software technology. For designing of the new type improved aeroengine test system, a hardware and software co-design strategy is employed. After a thorough trade-off analysis and comparison among different hardware and software systems, an embedded aeroengine test system based on ARM and FPGA is designed, by using S3C2440A CPU with ARM920T core and FPGA from Xilinx as fundamental hardware data acquisition and process platform, using Linux as real time operating system. The data transmission between ARM and FPGA take the path of dual-port RAM, during which the read-write operation is coordinated by means of interruption. The system uses U-Boot to initialize hardware and load operating system. FPGA is used as foreside of data acquisition system, which sampling parameter setting is loaded by reading configuration file during start-up and read into inner register by SPI bus. Data is exported from flash-chip of test system by means of U-disk or network, and analyzed in PC equipped with specialized software. Strong post-proceeding capacity for multi parameters of aeroengine rig testing can be realized, especially for dynamic signal analysis in time domain, frequency domain. Because of the use of the new platform, a big promotion has been achieved. I) the capacity of data processing increases by 15%. II) The new system allows numbers of the sampling channels to double. III) Abundant functions of software can realize more professional, intelligent and generic tests. IV) Sampling frequencies increases by 20%, meeting the demand of monitoring dynamic random signals such as noise and vibration, on fluctuating pressure with wide frequency band. The embedded aeroengine test system based on ARM and FPGA is successful and the prototype is manufactured and tested. It is found that the performance of the new system is promoted significantly, which shows the effectiveness and reliability of the method employed.

Simple Harmonic Excitation Numerical Analysis and Experimental Study of Space Bidirectional Beam String Structure

In this paper,a two-way winding-beam space-harmonic excitation beam string under the action of the dynamic response has been studied to capture the dynamic response of the structure of the law, identify the structure of the weak components,and for the design and construction to provide the necessary theoretical data. Using ANSYS finite element software to numerical analysis and reduced scale quarter ratio of model test research methodology to study,using experimental test results and finite element numerical analysis of mutual authentication.Numerical analysis taking into account the geometric non-linear structure,carried out static analysis,modal analysis,harmonic analysis and transient response time-history analysis. Experimental studies of the dynamic signal acquisition and analysis and processing, through the comparative analysis of data, master of the winding space for a two-way steel beam string dynamic response law obtained structural response of the frequency response range,weak location and distribution of components of type of structural design and construction process were proposed.