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- Inertial navigation system (4)
- Magnetic field (4)
- Embedded systems (3)
- Fiber Bragg grating (3)
- Inertial measurement unit (3)
- Magnetostriction (3)
- Person tracking (3)
- Sensor calibration and validation (3)
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- 3D sensor (2)
- Air-coupled (2)
- Cellular polypropylene (2)
- Digital image correlation (DIC) (2)
- Digitale Bildkorrelation (DIC) (2)
- Dynamic testing (2)
- Dynamische Tests (2)
- Ferroelectret (2)
- Fiber bragg grating (2)
- Funksensorik (2)
- Hazardous scenarios (2)
- Magnetostrictive metal coating (2)
- RSSI (2)
- SHM (2)
- Self-diagnostic fiber optical sensor (2)
- Sensornetzwerk (2)
- Spannungs-Dehnungs-Kurve (2)
- Split Hopkinson pressure bar (SHPB) (2)
- Stress-strain curve (2)
- Strukturüberwachung (2)
- Transducer (2)
- Wireless sensor network (WSN) (2)
- 3D calibration method (1)
- ACC (1)
- Accelerometer (1)
- Accelerometers (1)
- Actuators (1)
- Adhesive joint (1)
- Air-based (1)
- Air-coupled ultrasonic testing (1)
- Auto-validation (1)
- Automatic 3D calibration (1)
- BLE (1)
- Bluetooth (1)
- Bluetooth Low Energy (1)
- Calibration (1)
- DDS (1)
- Data fusion (1)
- Data-fusion (1)
- Dead reckoning (1)
- Deep learning (1)
- Early damage detection (1)
- Early-damage-detection (1)
- Fatigue behaviour (1)
- Ferroelectrets (1)
- Fiber Bragg gratings (1)
- Fibre Bragg grating (1)
- Finite element methods (1)
- Focused sound fields (1)
- Focused transducers (1)
- Focusing (1)
- GYRO (1)
- Global Positioning System (1)
- Guided wave (1)
- Gyroscope (1)
- Gyroscopes (1)
- Indoor localization (1)
- Indoor positioning (1)
- Indoor positioning error reduction (1)
- Inertial navigation (1)
- Inertial tracking (1)
- Lamb wave (1)
- Lamb-waves (1)
- Localization (1)
- Long-Term Monitoring (1)
- MAG (1)
- Machine learning (1)
- Magnetic field measurement (1)
- Magnetic field sensor (1)
- Magnetic sensors (1)
- Measurement (1)
- Measurement uncertainty (1)
- Mesh routing (1)
- Modeling and simulation (1)
- Moisture (1)
- Moisture Measurement (1)
- Monitoring (1)
- Moving person localization (1)
- Multi-Hop WSN (1)
- Multi-hop (1)
- Multi-sensor (1)
- Multi-sensor device (1)
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- Multihop (1)
- Multisensor system (1)
- Network (1)
- Non-destructive evaluation (1)
- Patch (1)
- Rosette (1)
- Schadensfrüherkennung (1)
- Self-calibration-method (1)
- Self-diagnosis (1)
- Sensor (1)
- Sensor fusion (1)
- Strain gauge factor (1)
- Structural Health Monitoring (1)
- Structural health monitoring (1)
- Temperature and Frequency Compensation (1)
- Temperaturkompensation (1)
- Ultrasonic (1)
- Ultrasonic testing (1)
- Ultrasound (1)
- Validation (1)
- WSN (1)
- Water dipoles (1)
For the accuracy of inertial navigation systems for indoor localization it is important to get high quality sensor data of the multi-sensor system. This can be realized using high quality sensors or the developed 3D-self-calibration-method for low cost sensors. Based on the calibration procedure of the accelerometer (ACC) and the magnetic field sensor (MAG), the additional integration of the gyroscope (GYRO) leads to a reduction of the indoor positioning error. This improves both the approximation for the accelerometer, the magnetic field sensor and the gyroscope so that the standard deviation of a single sensor is minimized. There are errors in the whole system. To determine these error sources it is important to define the measurement uncertainty. In this paper it is presented that the measurement uncertainty can be reduced by the application of the developed 3D-self-calibration method.
Sensor based person tracking is a challenging
topic. The main objective is positioning in areas without
GPS connection, i.e. indoors. A research project is carried
out at BAM, Federal Institute for Materials Research and
Testing, to develop and to validate a multi-sensor system for
3D localization. It combines body motion sensing and a
guard system for the tracking and recording of the status of
persons. The so named BodyGuard system was designed for
sensor-based monitoring and radio-based transmission of
the movement of a person. Algorithms were developed to
transform the sensor data into a spatial coordinate. This
paper describes how the BodyGuard system operates, which
main components were used in the system, how the
individual sensor data are converted into 3D motion data,
with which algorithms the individual sensors are processed,
how individual errors are compensated and how the sensor
data are merged into a 3D Model. Final objective of the
BodyGuard system is to determine the exact location of a
person in a building, e.g. during fire-fighting operations.
A fibre Bragg grating (FBG) strain patch specially adapted for long-term and high-strain applications was developed and characterised. Additionally, in the case of unknown main stress axis, two fibre optic strain rosettes were developed. The design concept for the patch and the rosettes is based on a glass fibre reinforced plastic (gfrp) carrier material. The patches were characterised due to their strain gauge factor and fatigue behaviour. As a result, FBG strain patches with linear strain behaviour and excellent fatigue resistance were developed and can be used as part of a monitoring system for aerospace structures or wind turbine power plants. The rosettes were designed to be small in geometrical size and their strain transfer behaviour was characterised.
Damage to buildings occurs if a construction component fails. The result is a partial or total collapse which can be dangerous for people for example if it's a bridge or a large hall. The collapse of the terminal building at the Airport Charles de Gaulle in Paris and the damage at the historic City Archives of Cologne are typical examples of such accidents. Another problem is the contradiction of the increasing volume of traffic (particularly heavy traffic) and the great age of bridges. The probability increases that the load-bearing capacity of a bridge decreases. For example the collapses of the Mississippi Bridge and of the Inntal Motorway Bridge can be seen as results. Therefore it is necessary to control endangered structures during their life span.
In order to prevent these kinds of accidents, the Federal Institute for Materials Research and Testing developed a radio-based, self-configuring measuring system in cooperation with the ScatterWeb Company, Berlin (Germany). This measuring system consists of identically designed sensor modules which are self-sustaining, wireless, act as transmitters and receivers and are equipped with a special sensor technology for long-term monitoring of buildings or engineering facilities. The sensor unit uses strain gauges for stress analysis and contains interfaces for additional sensors. The system in particular applies to buildings and structures for transport and traffic and large-scale industrial facilities, where a subsequent wiring installation is difficult or impossible.
A multi-sensor system for 3D localization was developed and named BodyGuard. It combines body movement sensing and a guard system for the tracking and recording of the status of persons. BodyGuard was designed to monitor and transmit the movement of a person radio-based and to transform that data into a spatial coordinate. This paper describes how the BodyGuard system works, what components the system consists of, how the individual sensor data is converted into 3D motion data, with which algorithms the individual sensors are processed, how individual errors are compensated and how the sensor data are fused into a 3D Model.
In this study a method for early damage detection is investigated based on the directed excitation and measuring of Lamb waves (guided waves). The objective is to make a statement about the practicability of a Lamb wave generator (LWG) and about the application relevant parameters (specimen materials and dimensions, wave characteristics, excitation, transmission und reflection). Guided waves enable an effective differentiation of structural and defective indications as well as a classification of different defect types. For the investigations, a LWG was developed which combines the advantages of the single excitation of a piezoelectric actuator and the possibility of a group excitation. Algorithms were developed to identify and analyze damage patterns (cracks, wholes, weakening).
Limited access to the object of relevance is often an essential problem in testing routines, e.g. for non-destructive testing of industry facilities or components of means of transportation. The presented project is about the development of a non-destructive testing method for application over great distances (up to 100 m). The method is based on directed excitation and measuring of Lamb waves (guided waves). It enables an effective differentiation of structural and defective indications as well as a classification of different defect types.
The advantage of guided waves is the ability of propagation over great distances. This offers innovative possibilities for the investigation of large or difficult to access constructions. The testing method can be helpful in a broad variety of applications. It is useable for the characterization of plane or cylindrical, thin-walled surfaces of metal or fiber laminated materials. Particularly the investigation of aircraft wings and other aerospace components as well as the investigation of pipelines are addressed fields of application.
Wireless sensor network for long-term structural health monitoring of buildings and infrastructures
(2009)
Damage commonly occurs in buildings when a component fails suddenly with a
partial or total collapse as a consequence. This type of event leads to serious damage to property
and if it is a bridge or a large hall, then people in particular are at risk. The often great age of
bridges and the increasing volume of traffic (particularly heavy traffic) which they are expected
to carry are in clear contradiction to each other. Thus the probability increases that the loadbearing
capacity of a bridge decreases rapidly and often unnoticed with sometimes dire
consequences.
In order to prevent such accidents, the Federal Institute for Materials Research and Testing is
currently developing a special radio-based, self-configuring measuring system in cooperation
with the Berlin-based ScatterWeb Company. This measuring system consists of a number of
identically designed sensor nodes which are self-sustaining, need no wiring, can act as both
transmitters and receivers and are equipped with a special sensor technology making long-term
monitoring of buildings or engineering facilities possible. The sensor unit uses strain gauges for
stress analysis and contains interfaces for additional sensors. The system in particular applies to
buildings and structures for transport and traffic and large-scale industrial facilities, where a
subsequent wiring installation is difficult or impossible.
Fiber optic sensors have gained increasing importance in recent years and are well established in many areas of industrial applications. In this paper, we introduce a concept of a self-diagnostic fiber optic sensor. The presented sensor is to resolve the problems of embedded fiber optic sensors in complex structures and to enable the validation under operational conditions. For this purpose, different magnetostrictive coated fiber optic sensors were developed and various experiments were performed to verify their mode of Operation and to determine the respective reproducibility. The measuring principle is illustrated by obtained experimental results, which showed a change in wavelength from 1 pm at a magnetic field strength change of 0.25 mT.
In addition, the temperature characteristics of the implemented magnetostrictive sensor were analyzed and an experimental factor of 1.5 compared to a reference fiber optic sensor was determined.