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EN
With the emergence of the Industry 4.0 concept, machine vibration monitoring and diagnostics systems based on the so-called smart vibration sensors using MEMS accelerometers become very popular on the market. Many automation companies use specifically designed for CbM industrial vibration sensors based on electronic chips with enclosed MEMS accelerometers. However, in the commercial vibration sensors datasheets very often are not provided detailed metrological parameters like frequency response in the declared frequency band. The article presents the results of research concerned to identification of frequency response of an exemplary available on market digital accelerometer dedicated to machines condition monitoring. The determined characteristics indicate that the sensor can be used for basic diagnostics of machines in accordance to the series of vibration standards ISO 10816 and ISO 20816. On the basis of the determined characteristics, it can be concluded that there are some non-linarites of the frequency response functions at the boundaries of the declared measurement band. It shows that application of that sensor to precise measurements conducted during scientific research could be limited.
EN
The study presents the finite element (FE) model update of the existing simple-spans steel-concrete composite bridge structure using a particle swarm optimisation (PSO) and genetic algorithm (GA) approaches. The Wireless Structural Testing System (STS-WiFi) of Bridge Diagnostic, Inc. from the USA, implemented various types of sensors including: LVDT displacement sensors, intelligent strain transducers, and accelerometers that the static and dynamic historical behaviors of the bridge structure have been recorded in the field testing. One part of all field data sets has been used to calibrate the cross-sectional stiffness properties of steel girders and material of steel beams and concrete deck in the structural members including 16 master and slave variables, and that the PSO and GA optimisation methods in the MATLAB software have been developed with the new innovative tools to interface with the analytical results of the FE model in the ANSYS APDL software automatically. The vibration analysis from the dynamic responses of the structure have been conducted to extract four natural frequencies from experimental data that have been compared with the numerical natural frequencies in the FE model of the bridge through the minimum objective function of percent error to be less than 10%. In order to identify the experimental mode shapes of the structure more accurately and reliably, the discrete-time state-space model using the subspace method (N4SID) and fast Fourier transform (FFT) in MATLAB software have been applied to determine the experimental natural frequencies in which were compared with the computed natural frequencies. The main goal of the innovative approach is to determine the representative FE model of the actual bridge in which it is applied to various truck load configurations according to bridge design codes and standards. The improved methods in this document have been successfully applied to the Vietnamese steel-concrete composite bridge in which the load rating factors (RF) of the AASHTO design standards have been calculated to predict load limits, so the final updated FE model of the existing bridge is well rated with all RF values greater than 1.0. The presented approaches show great performance and the potential to implement them in industrial conditions.
EN
This paper presents the concept of diagnosing the technical condition of mechanical devices. The test is based on a non-invasive vibration analysis technique combined with the use of artificial intelligence method. The object of the research is an electric motor for which vibrations were recorded by a vibration sensor based on four 3-axis digital accelerometers and MPU-6050 gyroscopes. The effectiveness of classification methods using the two-class and one-class classification was compared. It has been shown that the use of an incomplete pattern of the vibration model and a single-class classifier allows for effective detection of anomalies in the operation of an induction motor. Satisfactory classification efficiency was achieved, despite the limitation of the teaching set only to the information obtained during the correct operation of the device. The described method is universal and can be used to diagnose the technical condition of many different types of technical devices.
4
Content available remote Zastosowanie efektu tunelowego w akcelerometrach o wysokiej czułości
PL
We wstępie artykułu opisano kwantowo-mechaniczny efekt tunelowy. Wykonano obliczenia strzałki ugięcia mikrobelki krzemowej pod wpływem przyspieszenia. Obliczono też natężenie prądu tunelowego, płynącego przez złącze utworzone między końcem igły o atomowej grubości ostrza zamocowanej na mikrobelce i powierzchnią Przedstawiono projekt czujnika przyspieszenia o wysokiej czułości, w którym zastosowano układy takich złącz połączone szeregowo i równolegle. Przedyskutowano otrzymane wyniki oraz możliwości zastosowania takich czujników przyspieszenia w szczególności jako precyzyjnych grawimetrów.
EN
The quantum-mechanical tunneling effect is described in introduction of the article. Computation of the bending arrow of the microcantilever undergo acceleration are conducted. A tunneling current intensity flowing in the junction between tip of the needle witch atomic size thickness connected with the microcantilever made of silicone and surface are also executed. The project of the high sensitivity accelerometer based on systems of the junction connected parallel and in series is presented. Obtained results and feasibility of the application of the considered system in accelerometers, especially in precision gravimeters are discussed.
PL
W artykule przedstawiono algorytm opracowany do przetwarzania sygnałów pomiarowych z 3-osiowego akcelerometru, które przyjęto do opisu ruchu pióra podczas odręcznego pisania cyfr. Do rozpoznawania wspomnianych symboli zastosowano metodę DTW z uwzględnieniem różnych kryteriów detekcji. W artykule zaprezentowano wyniki oceny dokładności rozpoznawania cyfr arabskich. Wykazano, że dokładność rozpoznawania cyfr arabskich metodą DTW zależy od przyjętego kryterium detekcji.
EN
The article presents an algorithm developed for processing measurement signals from a 3-axis accelerometer, which was adopted to describe the movement of the pen when writing digits by hand. The DTW method was used to recognize these symbols, taking into account different detection criteria. The article presents the results of the assessment of the accuracy of digits recognition. It has been shown that the accuracy of digits recognition using the DTW method depends on the adopted detection criterion.
EN
When driving on a road with an uneven surface, the tractor receives shocks and oscillates. The main components that protect the tractor from the dynamic action of the road and reduce fluctuarions and vibrations to an acceptable level are the steered axle and tires. A serviceable steered axle of a wheeled tractor provides optimal controllability, traffic safety, durability and reliability of work. The work with faulty components of the steered axle impairs the controllability and stability of the tractor, reduces the safety of its movement, impairs ergonomic indications. A faulty steered axle contributes to the vibration of the tractor frame, as a result of which riveted and threaded connections are weakened, the alignment of the engine and gearbox is disturbed, and additional loads occur in the body parts. Vibration of the whole tractor accelerates wear and causes breakage of many parts. Therefore, monitoring the technical condition of the steered axle of a wheeled tractor is an actual task in the field of exploitation and repair of equipments. The article presents a method for determining the location of accelerometers for vibration diagnostics of steered axles of wheeled tractors.
PL
Podczas jazdy po drodze o nierównej nawierzchni ciągnik ulega wstrząsom i drganiom. Głównymi elementami, które chronią ciągnik przed dynamicznym działaniem drogi i redukują do akceptowalnego poziomu wahania i wibracje, są oś kierowana i opony. Sprawna oś skrętna ciągnika kołowego zapewnia optymalną sterowność, bezpieczeństwo ruchu, trwałość i niezawodność pracy. Praca z wadliwymi elementami osi pogarsza sterowność i stabilność ciągnika, zmniejsza bezpieczeństwo jego poruszania się, pogarsza ergonomię wskazań. Wadliwa oś przyczynia się do wibracji ramy ciągnika, w wyniku czego osłabione są połączenia nitowane i gwintowane, zaburzone jest osiowanie silnika i skrzyni biegów, a w częściach nadwozia występują dodatkowe obciążenia. Dlatego monitorowanie stanu technicznego osi ciągnika kołowego jest rzeczywistym zadaniem w zakresie eksploatacji i naprawy urządzeń. W artykule przedstawiono metodę wyznaczania położenia akcelerometrów do diagnostyki drganiowej osi k ciągników.
PL
Artykuł przedstawia zastosowanie metody Monte Carlo do parametrycznej identyfikacji akcelerometrów w dziedzinie częstotliwości. Omówione zostały dwie metody identyfikacji: intuicyjna, realizowana wyłącznie w oparciu o punkty pomiarowe charakterystyki amplitudowo-częstotliwościowej i bazująca na klasycznej metodzie najmniejszych kwadratów oraz procedura oparta na punktach pomiarowych obu charakterystyk częstotliwościowych (amplitudowej i fazowej), realizowana przy wykorzystaniu uogólnionej metody najmniejszych kwadratów. Przedstawiono wyniki identyfikacji dla wybranego akcelerometru typu Althen 731-207, a dla potrzeb realizacji obu metod identyfikacji zastosowano oprogramowanie Mathcad 14.
EN
The paper presents an application of the Monte Carlo method for parametric identification of accelerometers in the frequency domain. Two identification methods are discussed here. The first one is intuitive and implemented only based on measuring points of amplitude-frequency response and employs the classical least squares method. The second one is the procedure based on measuring points of both frequency responses (amplitude and phase) and implemented by using the generalized least squares methods. Identification results for the selected accelerometer of type Althen 731-207 are presented and discussed. Mathcad 14 software was used for the needs of both identification methods.
8
EN
Limb tremor measurements are one factor used to characterize and quantify the severity of neurodegenerative disorders. These tremor measurements can also provide dosage-response feedback to guide medication treatments. Here, we propose a system to automatically measure limb tremors in home or clinic settings. The key feature of proposed method is that it is contactless; not requiring a user to wear or hold a device or marker. Our sensor is a Kinect 2, which measures color and depth and estimates rough limb motion. We show that its pose accuracy is poor for small limb tremors below 10 mm amplitude, and so we propose an additional level of tremor tracking that recovers limb motion at a higher precision. Our method upgrades the sensitivity to achieve detection and analysis for tremors down to 2 mm amplitude. We include empirical experiments and measurements showing improved tremor amplitude and frequency estimation using our proposed Pose and Optical Flow Fusion (POFF) algorithm.
EN
The aim of this study was to analyse absolute and relative reliability of a number of postural static stability measures obtained from a GYKO inertial sensor system in young adults. Methods: The study examined 29 healthy non-athlete young adults. A test was performed for 30 s while standing on one foot, without moving, with eyes open and arms relaxed along the sides of the body. The examinations were performed twice, with a one-week interval. Relative reliability was measured using the intraclass correlation coefficient (ICC) and the 95% confidence interval (95% CI), whereas the absolute reliability was evaluated based on the standard error of measurement (SEM) and the minimal detectable change (MDC). Results: The results of this study showed moderate to good relative reliability scores for all the postural stability measures, with ICC values ranging from 0.62 to 0.70. For most of the analysed variables, SEM% ranged from ca. 10 to 14%. Relatively high SEM% values were obtained only for two variables (Area, Convex Hull Area). Conclusions: The low costs of GYKO inertial sensor systems, the fast and easy installation, the mobility and high reliability of the measurement of postural stability show that it can be effective alternative to stabilographic platforms.
10
Content available remote Badanie modułu przyspieszenia na potrzeby diagnostyki czujników inercyjnych
PL
W artykule przedstawione zostały wyniki badań stabilności modułu przyspieszenia grawitacyjnego czujników inercyjnych wykonanych w technologii MEMS (Micro Electro Mechanical Systems). Tego typu pomiary analizowane są w szczególności na potrzeby tzw. nawigacji inercyjnej. W referacie zaprezentowano badania porównawcze dwóch czujników wykonanych w technologii MEMS, na podstawie których wybrano najlepsze rozwiązanie pod względem stabilności modułu przyspieszenia grawitacyjnego.
EN
The article presents the results of the stability study of the gravitational acceleration module of inertial sensors performed in MEMS (Micro Electro Mechanical Systems) technology. Such measurements are analysed in particular for the needs of inertial navigation. The paper presents comparative studies of two sensors made in MEMS technology, based on which the best solution in relation to stability of the gravitational acceleration module has been selected.
PL
Artykuł dotyczy dokładności pomiaru kątów z wykorzystaniem czujników inercyjnych w trójwymiarowym układzie współrzędnych. Jako system odniesienia wykorzystano system akwizycji ruchu firmy Vicon. W artykule opisano przebieg badania, aplikację, która posłużyła do zbierania danych ze smartfona. W artykule zawarto także metody, wzory oraz algorytm, których użyto, aby porównać uzyskane dane.
EN
This article discusses angle measurement accuracy assessment using inertial sensors in three-dimensional coordinate system. Vicon's acquisition system was used as a reference system. The article describes conduct of the study and application that was used for collecting data from the smartphone. The article also contains methods, formulas and algorithms that were used to compare obtained data.
PL
W ramach pracy przedstawiono układ pomiarowy umożliwiający zbieranie oraz zapis parametrów ruchu pojazdu. Do budowy układu, wykorzystano moduł nawigacji inercyjnej składający się z trójosiowych akcelerometrów oraz żyroskopów wykonanych w technologii MEMS. Wykonano badania oraz opracowano metody obliczeniowe pozwalające na odniesienie zebranych danych, do punktu w przestrzeni trójwymiarowej, w celu wyznaczenia trajektorii ruchu pojazdu. Zbudowany układ pomiarowy wykorzystuje trzy rodzaje czujników: akcelerometr, żyroskop, magnetometr. Każdy z tych czujników pozwala na pomiar wielkości fizycznej, w trzech prostopadłych osiach kartezjańskiego układu współrzędnych. Dodatkowo w pracy wykorzystano moduł nawigacji satelitarnej (GPS), jako odniesienie w skali „makro” (układ współrzędnych związany ze środkiem kuli ziemskiej o promieniu wynoszącym ok. 6371 km) dla modułu nawigacji inercyjnej (INS/IMU), umożliwiającej dokładny pomiar w skali „mikro” (układ współrzędnych związany z punktem początkowym ruchu dla trasy, której długość nie przekracza kilkuset metrów). W artykule przedstawiono przegląd dostępnych czujników pomiarowych ze szczególnym uwzględnieniem parametrów wybranych sensorów oraz błędów wprowadzanych do układu pomiarowego.
EN
As part of the work, a measuring system is presented that allows collecting and recording vehicle motion parameters. To build the system, an inertial navigation module was used, consisting of two-axis accelerometers and gyroscopes made in MEMS technology. The tests were carried out and calculation methods were developed to allow the collected data to be referenced, to a point in the three-dimensional space, in order to determine the trajectory of the vehicle's movement. The built-in measuring system uses three types of sensors: accelerometer, gyroscope, magnetometer. Each of these sensors allows the measurement of the physical size in three orthogonal axes of the Cartesian coordinate system. In addition, the work uses a satellite navigation module (GPS), as a reference on the "macro" scale (coordinate system related to the center of the globe with a radius of about 6371 km) for the inertial updating module (INS / IMU), enabling accurate measurement in the "micro" scale (the coordinate system associated with the starting point of the traffic for the route, the length of which does not exceed several hundred meters). The article presents an overview of available measuring sensors with special consideration of the parameters of selected sensors and errors introduced into the measurement system.
EN
It is well known that postural stability is influenced by visual stimuli. The influence of saccadic eye movement on postural control has been described, however, a specific response of different body segments has not been studied yet. Therefore, the aim of this study was to assess the effect of horizontal and vertical saccadic eye movements on postural stability with specific focus on upper trunk, lower trunk and lower limbs movement variability and complexity. Methods: Eighteen elderly participants (aged 70.3 ± 7.7 years) stood in bipedal stance in three visual conditions – horizontal saccades, vertical saccades and fixation. Accelerometers were attached to their lower back, sternum and shanks. Movement variability of each body segment was described by root-mean-square and sample entropy of acceleration. Results: The results of the present study revealed significant influence of saccadic eye movements on anterior-posterior and vertical shanks, and vertical lower trunk movement variability described by root-mean-square. Conclusions: The correlations between results of the observed segments showed segment-specific variability patterns but generalised complexity pattern.
PL
Celem pracy jest zaprezentowanie sprawdzenia poprawności tezy, czy możliwe jest określenie wartości chwilowych mocy pojazdu pod kątem ich wykorzystania do wyznaczenia charakterystyki mechanicznej silnika spalinowego, elektrycznego lub napędu hybrydowego, podczas eksperymentów ruchowych pojazdu. Artykuł poświęcony jest różnym sposobom przetwarzania danych pomiarowych, uzyskanych z akcelerometru 3D w trakcie ruchu pojazdu.
EN
Currently, accelerometers are installed in the majority of commercially available smartphones. The paper proposes the use of a 3D accelerometer installed in a smartphone to measure vehicle motion parameters. The measured values obtained were subjected to filtration using an approximation of the spline function, so that they could be used for further testing. The main purpose of the work is to check if it is possible to estimate the instantaneous power of the vehicle, which can be used to determine the mechanical characteristics of an internal combustion engine, electric engine or hybrid drive during physical experiments. The tests carried out allowed the estimation of vehicle motion parameters.
PL
W pracy przedstawiono prototyp zdigitalizowanego systemu pomiarowego do diagnostyki biomechaniki ludzkiego ciała. System pomiarowy zostanie zbudowany w ramach projektu dofinansowanego ze środków Unii Europejskiej, pod tytułem „Mobilne urządzenie do ortopedycznej diagnostyki biomechaniki i motoryki ludzkiego ciała”. W pracy przedstawiono dwie metody obliczania orientacji obiektu w przestrzeni 3D: metodę Madgwicka i filtr Kalmana. Zaprezentowano również stanowisko laboratoryjne do testowania zaproponowanych algorytmów oraz uzyskane wyniki badań.
EN
This paper presents assumptions and a prototype of a digitized measurement system for the diagnosis of human body biomechanics. The measurement system will be built as part of a project subsidized by the European Union, titled "Mobile device for orthopedic diagnostics of biomechanics and motility of the human body". The paper presents two methods for calculating the orientation of an object in 3D space: the Madgwick method and the Kalman filter. A laboratory stand for testing the proposed algorithms and obtained test results were also presented.
EN
MEMS are one of the fastest developing branch in microelectronics. Many integrated sensors are widely used in smart devices i.e. smartphones, and specialized systems like medical equipment. In the paper we present the main parts of a system for measuring human movement which can be used in human balance disorder diagnosis. We describe our design of capacitive accelerometers and dedicated switched capacitor readout circuit. Both will be manufactured as separate chips in different technological processes. The principle of operation, schematics and layouts of all parts of the system are presented. Preliminary simulations show that the proposed designs are applicable for the considered medical device.
EN
A gravity damper is a one-way valve, employed for regulating the airflow rate in ducts, generally constituted by a series of rectangular panels (closure sections), connected to an articulated quadrilateral synchronizing the movements. If the device needs to process large masses of high speed air, as common in the case of energy conversion systems, disadvantageous dynamic effects can occur. In this study, vortexinduced vibration (VIV), occurring on a gravity damper for high values of the Reynolds number, is investigated. The analysis of this work couples numerical methods (Computational Fluid Dynamics with Large-Eddy Simulation turbulence model and Finite Element Method) to experiments: a full-scale accelerometric measurement campaign is actually performed at the wind tunnel facilities of the University of Perugia. VIVs are diagnosed and quantified through the experimental vibration analysis, which is interpreted through numerical simulations. The large amplitude of VIV is interpreted as due to a tendency towards lockin because of the approaching of the vortex shedding frequency to a natural vibration mode of the system. The integrated numerical and experimental framework finally inspires two different design solutions for mitigating the amplitude of VIV: these strategies are tested at the wind tunnel and they are indeed shown to be effective.
PL
Praca dotyczy porównania regularności próbkowania trójosiowych czujników przyspieszenia w popularnych smartphone'ach, przedstawiono zestawienie czujników niektórych telefonów. Podstawowym analizowanym parametrem jest stabilność częstotliwości próbkowania w zależności od używanego systemu operacyjnego i producenta urządzenia. Analizę prowadzono tak by wybrane smartphony były wyposażone w różne czujniki pomiarowe - akcelerometry. Zaprezentowano przykład zastosowania pomiarowego - porównawczy pomiar drogowy.
EN
The work is a description of metrological properties and their comparison for triaxial acceleration sensors (MEMS - MicroElectro-Mechanical System, IMU - Inertial Measurement Unit) in popular and modern smartphones. A comparison of the components of some phones is presented. The stability of the sampling time is the basic parameter which is analyzed. Sampling time in analog-to-digital converters (inside MEMS units) depends on the operating system of smartphone and its components (processor, RAM) which are used in its construction. The analysis was performed in order to select smartphones which are equipped with different measuring systems - MEMS accelerometers. The Android and iOS operating systems are used in research. The comparative road measurement is presented as an example of measuring application with smartphones. Physics Toolbox Sensor Suite software (free software for iOS and Android) used in the measurement of a vehicle motion. Results for 3D acceleration signals processing with variable sampling time are presented and compared for different smartphones.
EN
Currently, triaxial (3D) accelerometers are installed in every smartphone, so paper proposes to use such an accelerometer in vehicle motion measurement. The work describes a conception of the utilization of 3D accelerometer in smartphone to the determination of the car speed and the estimation of a power on the vehicle wheels. The analysis of the results was conducted based on road measurements. The basic issues which were discussed: calibration of acceleration sensor and processing of acceleration signals with variable sampling time resulting from the properties of the smartphone operating system. The smartphone (iPhone 4s) uses the accelerometer LIS331DLH (in Microelectromechanical systems technology MEMS) 12-bit analog-to-digital converter for ±2g range. Moreover, the iOS system (ver. 9.3.5) was chosen because of the more stable sampling time than in the Android system. The article presents the following signal processing: 3D acceleration → longitudinal vehicle acceleration → vehicle speed →resultant power → power transmitted from the propulsion system.
PL
Praca opisuje koncepcję wykorzystania akcelerometru trójosiowego, instalowanego w smartphonie, do pomiaru prędkości pojazdu samochodowego oraz oszacowania mocy napędu przekazywanej na koła pojazdu. Analizę wyników przeprowadzono na podstawie pomiarów drogowych. Podstawowymi opisywanymi zagadnieniami są: kalibracja czujnika przyspieszenia oraz przetwarzanie sygnałów przyspieszenia o zmiennym czasie próbkowania urządzenia mobilnego.
20
Content available Fuzja sensoryczna IMU metodą filtra Kalmana
PL
W pracy przedstawiono metody pomiaru orientacji obiektu w przestrzeni. Na potrzeby określenia orientacji obiektu (attitude) estymowano lotnicze kąty Eulera RPY - Roll, Pitch, Yaw. Do pomiaru poszukiwanych wielkości wykorzystano mikroprocesorowy inercyjny układ pomiarowy (IMU). Dzięki fuzji sensorycznej zintegrowano dane pochodzące z fizycznie odseparowanych, niezależnych czujników IMU. W celu sprawdzenia poprawności fuzji sensorycznej zaimplementowano filtrację Kalmana w środowisku inżynierskim Matlab oraz na mikrokontrolerze a uzyskane wyniki pomiarów przedstawiono na przebiegach czasowych. W wyniku modelowania procesu pomiarowego oraz jego implementacji i filtracji w sterowniku cyfrowym uzyskano odfiltrowane przebiegi wielkości określających orientację obiektu w przestrzeni.
EN
The article describes method of measurement of 6DOF object’s attitude. For the purposes of determining the object orientation (attitude) estimation of airline Euler angles Roll, Pitch, Yaw. There are three types of sensor using for this purpose: accelerometer, gyroscope and magnetometer. Working as a measurement system uses a microprocessor RAZR IMU 9-DOF. Three types of independent signals are connected using Kalman Filter Fusion developed on the basis of designated signal models and their dependencies in space state. The validity of the assumptions made by implementing the Kalman filter engineering environment of Matlab. The results of numerical experiments are presented in the form of time passes selected parameters that describe the orientation of the object. Designed filtration system is implemented in the electronic layout of the IMU and test research. As a result of the study was obtained from the sensor signals are filtered out. Registered time characteristics were presented in work.
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