Combined Measurement System Research Articles

Unmanned Ground Vehicle Energy Efficiency Validation in Territory Surveillance Mission

This paper describes test case of an energy efficiency validation method. Test case is selected as surveillance mission which is simple and common case for universal unmanned ground vehicle where environment dynamics has major influence. The prototype UGV platform is equipped with combined measurement system providing data about dynamic parameters of platform physical movement as well as real-time energy consumption. Platform energy efficiency is evaluated on several stages, enabling to evaluate both mechanical design and control system algorithms. In addition, environment interaction with the vehicle is measured also for analyzing the vehicle limitations and scope of use. Real-condition missions are used for vehicle design validation purposes.

A Rapid Coordinate Transformation Method Applied in Industrial Robot Calibration Based on Characteristic Line Coincidence.

Coordinate transformation plays an indispensable role in industrial measurements, including photogrammetry, geodesy, laser 3-D measurement and robotics. The widely applied methods of coordinate transformation are generally based on solving the equations of point clouds. Despite the high accuracy, this might result in no solution due to the use of ill conditioned matrices. In this paper, a novel coordinate transformation method is proposed, not based on the equation solution but based on the geometric transformation. We construct characteristic lines to represent the coordinate systems. According to the space geometry relation, the characteristic line scan is made to coincide by a series of rotations and translations. The transformation matrix can be obtained using matrix transformation theory. Experiments are designed to compare the proposed method with other methods. The results show that the proposed method has the same high accuracy, but the operation is more convenient and flexible. A multi-sensor combined measurement system is also presented to improve the position accuracy of a robot with the calibration of the robot kinematic parameters. Experimental verification shows that the position accuracy of robot manipulator is improved by 45.8% with the proposed method and robot calibration.

A combined liquid sodium flow measurement system

A combined liquid sodium flow measurement system

A combined liquid sodium flow measurement system

A combined liquid sodium flow measurement system

Development of a Combined Measurement System for Torque and Angular Position

In this article a combined contactless measurement method is presented which is based on angle differences. The aim is the development of a combined, optical measurement system to determine the angular position of a shaft and the applied torque on it as well as an appropriate production technology to apply markings. Two independent modules are used which separately allow the measurement of angular position and rotational speed and if combined can measure torque. To ensure a simple integration of the system into any application, position markings are directly applied on the shaft using a laser. The selected technological approach is based on a contactless measurement method using angle differences. The concept as well as first research results are presented.

Digital combined measuring technology assisted quality inspection for aircraft assembly

Aimed at the issues,including that detail features of the large size aircraft panel components couldn't be achieved directly and the low measuring efficiency by using a laser tracker separately in large size aircraft panel shape measurement,a combined measurement method based on the laser tracker and the articulated arm coordinate measuring machine( AACMM) was proposed. Under the premise of the measurement precision,by adding the AACMM to the measurement field of laser tracker,the detailed forming information of large size aircraft panel could be acquired comprehensively. According to the characteristics of the aircraft panel assembly process,some combined measurement tools were developed based on the Spatial Analyzer software,which could process all measurement data from the combined measurement system. Some examples are also given to illustrate the effectiveness and the efficiency of the method.

Visualization of Chemical Grout Permeation in Transparent Soil

This paper presents an experiment that visualizes the permeation of chemical grout in transparent soil. The low initial viscosity (5 mPa · s) urea-formaldehyde resin (UFR) was chosen as grouting material in this experiment. The transparent soil used in this study is made of fused silica and a calcium bromide solution with the same refractive index. Triaxial and permeability tests are carried out to demonstrate that the geotechnical properties and hydraulic permeability of this transparent soil are typical of granular soils and suitable for modeling natural sand in permeation problem. A combined grouting and optical measurement system is developed for this study, which consists of an air pressure driven grout injection station to inject grout into a transparent soil model, laser to illuminate the cross-section of interest inside the model, and a charge-coupled device (CCD) camera to capture a series of images during the whole grout injection and permeation process. Image processing techniques including digital image correlation (DIC) are applied to sequence of images to detect the edges of the grout bulb and displacement distribution. The relationship of the grouting radius and grouting time corresponds to Maag's formula on permeation grouting. As a result, the validity of this innovative experiment has been verified.

Combined non-contact coordinate measurement system and calibration method

A combined non-contact measurement system comprising attitude angle sensor, angle encoder, laser rangefinder, and total station is adopted to measure the spatial coordinate of the hidden zones in large-scale space. The laser from the total station is aimed at the optical system of the attitude angle sensor to obtain the spatial coordinate and the spatial attitude angles. Then, the angle encoder driven by a stepping motor is rotated to drive the laser rangefinder to direct at the measured point. This approach is used to obtain the distance from the rangefinder to the measured point and the angle of the angle encoder. Finally, the spatial coordinates of the measured point can be calculated by using these measured parameters. For the measurement system, we propose a weighted least squares (WLS) calibration method, in which weights are determined for the angular distribution density. Experimental results show that the measurement system could expand the scale and achieve reliable precision during combined measurement and the measurement error of the weighted least squares method is less than that of the ordinary least square (OLS) method.

PM2.5 emissions from light-duty gasoline vehicles in Beijing, China

As stricter standards for diesel vehicles are implemented in China, and the use of diesel trucks is forbidden in urban areas, determining the contribution of light-duty gasoline vehicles (LDGVs) to on-road PM2.5 emissions in cities is important. Additionally, in terms of particle number and size, particulates emitted from LDGVs have a greater health impact than particulates emitted from diesel vehicles. In this work, we measured PM2.5 emissions from 20 LDGVs in Beijing, using an improved combined on-board emission measurement system. We compared these measurements with those reported in previous studies, and estimated the contribution of LDGVs to on-road PM2.5 emissions in Beijing. The results show that the PM2.5 emission factors for LDGVs, complying with European Emission Standards Euro-0 through Euro-4 were: 117.4±142, 24.1±20.4, 4.85±7.86, 0.99±1.32, 0.17±0.15mg/km, respectively. Our results show a significant decline in emissions with improving vehicle technology. However, this trend is not reflected in recent emission inventory studies. The daytime contributions of LDGVs to PM2.5 emissions on highways, arterials, residential roads, and within urban areas of Beijing were 44%, 62%, 57%, and 57%, respectively. The contribution of LDGVs to PM2.5 emissions varied both for different road types and for different times.

Acute effect of heel-drop exercise with varying ranges of motion on the gastrocnemius aponeurosis-tendon’s mechanical properties

The objectives of this study was to investigate the acute effects of various magnitudes of tendon strain on the mechanical properties of the human medial gastrocnemius (MG) in vivo during controlled heel-drop exercises. Seven male and seven female volunteers performed two different exercises executed one month apart: one was a heel-drop exercise on a block (HDB), and the other was a heel-drop exercise on level floor (HDL). In each regimen, the subjects completed a session of 150 heel-drop exercises (15 repetitions×10 sets; with a 30 s rest following each set). Before and immediately after the heel-drop exercise, the ankle plantar flexor torque and elongation of the MG were measured using a combined measurement system of dynamometry and ultrasonography and then the MG tendon strain and stiffness were evaluated in each subject. The tendon stiffness measured prior to the exercises was not significantly different between the two groups 23.7±10.6N/mm and 24.1±10.0N/mm for the HDB and HDL, respectively (p>.05). During the heel-drop exercise, it was found that the tendon strain during the heel-drop exercise on a block (8.4±3.7%) was significantly higher than the strain measured on the level floor (5.4±3.8%) (p<.05). In addition, the tendon stiffness following the heel-drop exercise on a block (32.3±12.2N/mm) was significantly greater than the tendon stiffness measured following the heel-drop exercise on the level floor (25.4±11.4N/mm) (p<.05). The results of this study suggest that tendon stiffness immediately following a heel-drop exercise depends on the magnitude of tendon strain.

Simulations for the Development of Thermoelectric Measurements

In thermoelectricity, continuum theoretical equations are usually used for the calculation of the characteristics and performance of thermoelectric elements, modules or devices as a function of external parameters (material, geometry, temperatures, current, flow, load, etc.). An increasing number of commercial software packages aimed at applications, such as COMSOL and ANSYS, contain vkernels using direct thermoelectric coupling. Application of these numerical tools also allows analysis of physical measurement conditions and can lead to specifically adapted methods for developing special test equipment required for the determination of TE material and module properties. System-theoretical and simulation-based considerations of favorable geometries are taken into account to create draft sketches in the development of such measurement systems. Particular consideration is given to the development of transient measurement methods, which have great advantages compared with the conventional static methods in terms of the measurement duration required. In this paper the benefits of using numerical tools in designing measurement facilities are shown using two examples. The first is the determination of geometric correction factors in four-point probe measurement of electrical conductivity, whereas the second example is focused on the so-called combined thermoelectric measurement (CTEM) system, where all thermoelectric material properties (Seebeck coefficient, electrical and thermal conductivity, and Harman measurement of zT) are measured in a combined way. Here, we want to highlight especially the measurement of thermal conductivity in a transient mode. Factors influencing the measurement results such as coupling to the environment due to radiation, heat losses via the mounting of the probe head, as well as contact resistance between the sample and sample holder are illustrated, analyzed, and discussed. By employing the results of the simulations, we have developed an improved sample head that allows for measurements over a larger temperature interval with enhanced accuracy.

Non-diffracting beam based probe technology for measuring coordinates of hidden parts

A probe technique based on non-diffracting beam was proposed. The probe was combined with a total station or a laser tracker to form a combined measuring system that realized the coordinate measurement of hidden parts in large spaces. In the combined measurement system, the probe stylus was first set to touch the point of measurement, and the optical system of the probe was targeted by the total station or the laser tracker. This was used to measure the spatial coordinates of the probe. The probe transformed the laser that was used to measure distance into a non-diffracting beam through the axicon lens, and non-diffracting images were produced in CCD plane. The center of the non-diffracting beam mapped one to one to the incident direction of the laser, and the horizontal angle the probe were obtained via center fitting of the non-diffracting images. The inclinometer was used to measure the rolling angle and the pitching angle of the probe. Finally, all the measured attitude angles and position coordinates were combined and coordinate transformation was used to calculate the spatial coordinates of the measured point. Our results show that the probe could achieve milliradian-level precision when measuring the attitude angles, demonstrating more flexibility and reliable precision during combined measurement.

Investigation of droplet size distribution in two-phase flows using a combined method for recording droplet fluorescence and diffraction scattering of light

A prototype of a combined measurement system (MS) based on the fluorescent and small-angle methods of determining the parameters of a fuel-air spray using a pulsed laser as a light source and a color digital video camera to record spray sections was designed and tested. The tests of the MS showed that it has good performance and is suitable for determining the characteristics of advanced atomizers in a pressure chamber. Spatial concentration distributions of aerosols generated by a centrifugal atomizer were studied. Distributions of time-averaged Sauter diameters of droplets, their concentration, and the circumferential inhomogeneity of droplet concentration in the spray cross section were obtained. A study of fuel atomization from a plate was performed showing the possibility of using this device in power plants to improve the atomization performance compared to the atomization of a free jet in crossflow.

Design of Ultrasound Infrared Compound Distance Measurement System Based on LabVIEW

In order to meet the mobile robot’s accuracy and speed requirements in processing obstacle information based on the study of the principle of ultrasonic and infrared distance measurement, the ultrasonic infrared measurements system is designed using Mega16L microcontroller. The hardware of the system, data fusion and software components were studied. Bayes estimation for the data fusion, which can greatly improve the measurement accuracy, was used. The human-computer interface and back panel algorithm were developed with the development language of LabVIEW. Experimental results show that the measurement error of the combined measurement system is in ± 1mm between 0 ~ 300cm, which can meet the design requirements and flexible operation.

Identification of simultaneously active partial discharge sources using combined radio frequency and IEC60270 measurement

Using a newly developed measurement system, partial discharge (PD) activity has been recorded simultaneously on a pulse-by-pulse basis in terms of radiated radio frequency (RF) energy and the conducted apparent charge measured according to the IEC60270 standard. Two epoxy resin insulation samples containing voids have been activated separately and in parallel and the resulting PD was measured using the combined system. It has been shown that the combined measurement system has the ability to distinguish between discharges occurring simultaneously in each of the respective samples. This is evident in the appearance of separate clusters when the energy of the radio frequency discharge signal is plotted against the apparent charge for a large number of pulses. The identity of the defect producing each cluster has been confirmed by modelling the complete response of a gas-insulated-switchgear chamber to simulated Gaussian current pulses of known charge. The combined technique has also shown potential to distinguish between additional simultaneously active defects, including free metallic particles in oil. The combination of the two measurement systems may enable the classification of PD activity with a greater degree of confidence than conventional phase-resolved measurements allow when more than one defect is present.

In-situ observation of dynamic water behavior in polymer electrolyte fuel cell by combined method of Small-Angle Neutron Scattering and Neutron Radiography

In-situ observation was conducted on an operating polymer electrolyte fuel cell with a combined method of small-angle neutron scattering (SANS) and neutron radiography (NR). The combined measurement system has been recently developed to visualize water in a wide length scale from nano- to millimeter and successfully detected a spatial distribution of the water generated in individual cell elements; NR macroscopically detected the water in a gas diffusion layer and a flow-field, whereas SANS microscopically did in a membrane electrode assembly. In particular SANS was found to be a strong tool to make a rather precise analysis on the water content inside of ion conducting channels of polymer electrolyte membrane.

Estimating tropical cyclone precipitation from station observations

In this paper, an objective technique for estimating the tropical cyclone (TC) precipitation from station observations is proposed. Based on a comparison between the Original Objective Method (OOM) and the Expert Subjective Method (ESM), the Objective Synoptic Analysis Technique (OSAT) for partitioning TC precipitation was developed by analyzing the western North Pacific (WNP) TC historical track and the daily precipitation datasets. Being an objective way of the ESM, OSAT overcomes the main problems in OOM, by changing two fixed parameters in OOM, the thresholds for the distance of the absolute TC precipitation (D 0) and the TC size (D 1), into variable parameters. Case verification for OSAT was also carried out by applying CMORPH (Climate Prediction Center MORPHing technique) daily precipitation measurements, which is NOAA’s combined satellite precipitation measurement system. This indicates that OSAT is capable of distinguishing simultaneous TC precipitation rain-belts from those associated with different TCs or with middle-latitude weather systems.

Simultaneous scanning tunneling microscopy and stress measurements to elucidate the origins of surface forces

We have developed a new combined measurement system to investigate the underlying origins of forces on solid state surfaces from the viewpoint of atomic surface morphology. This system consists of two main parts: the measurements of force based on displacements and detailed atomic resolution observations of the surface morphology. The former involves a large sample cantilever and a capacitive detection method that provide sufficient resolution to detect changes of a few meV/atom or pN/atom at surfaces. For the latter, a scanning tunneling microscope was incorporated to observe structural changes occurring on the surface of the cantilever sample. Although this combined observation is not trivial, it was accomplished by carefully designing sample dimensions while suppressing the self-oscillation of the cantilever. To demonstrate the performance of this system a preliminary study of the room temperature adsorption of Br(2) on the clean Si(111)-7x7 surface is presented.

Simultaneous flux and current measurement from single plant protoplasts reveals a strong link between K+ fluxes and current, but no link between Ca2+ fluxes and current

We present a thorough calibration and verification of a combined non-invasive self-referencing microelectrode-based ion-flux measurement and whole-cell patch clamp system as a novel and powerful tool for the study of ion transport. The system is shown to be capable of revealing the movement of multiple ions across the plasma membrane of a single protoplast at multiple voltages and in complex physiologically relevant solutions. Wheat root protoplasts are patch clamped in the whole-cell configuration and current-voltage relations obtained whilst monitoring net K+ and Ca2+ flux adjacent to the membrane with ion-selective electrodes. At each voltage, net ion flux (nmol m(-2) sec(-1)) is converted to an equivalent current density (mA m(-2)) taking into account geometry and electrode efficiency, and compared with the net current density measured with the patch clamp system. Using this technique, it is demonstrated that the K+-permeable outwardly rectifying conductance (KORC) is responsible for net outward K+ movement across the plasma membrane [1:1 flux-to-current ratio (1.21 +/- 0.14 SEM, n = 15)]. Variation in the K+ flux-to-current ratio among single protoplasts suggests a heterogeneous distribution of KORC channels on the membrane surface. As a demonstration of the power of the technique we show that despite a significant Ca2+ permeability being associated with KORC (analysis of tail current reversal potentials), there is no correlation between Ca2+ flux and KORC activity. A very significant observation is that large Ca2+ fluxes are electrically silent and probably tightly coupled to compensatory charge movements. This analysis demonstrates that it is mandatory to measure flux and currents simultaneously to investigate properly Ca2+ transport mechanisms and selectivity of ion channels in general.

A combined system for measuring animal motion activities

In this study, we have developed a combined animal motion activity measurement system that combines an infrared light matrix subsystem with an ultrasonic phase shift subsystem for animal activity measurement. Accordingly, in conjunction with an IBM PC/AT compatible personal computer, the combined system has the advantages of both infrared and ultrasonic subsystems. That is, it can at once measure and directly analyze detailed changes in animal activity ranging from locomotion to tremor. The main advantages of this combined system are that it features real time data acquisition with the option of animated real time or recorded display/playback of the animal’s motion. Additionally, under the multi-task operating condition of IBM PC, it can acquire and process behavior using both IR and ultrasound systems simultaneously. Traditional systems have had to make separate runs for gross and fine movement recording. This combined system can be profitably employed for normative behavioral activity studies and for neurological and pharmacological research.