Accuracy Of Position Detection Research Articles

Design and Implementation of the Motor Position Detection System Based on CAN Bus

The rotor position of switched reluctance motor (SRM) is an essential information, and especially in high-performance SRM drive, it is important to achieve high resolution and real-time position detection. However, opto-coupler and linear encoder cant meet the demand of position detection accuracy. Moreover, if the controller detects the position directly, it is difficult to achieve a controller for remote control of the position detecting because of interference. In this paper, a novel position detecting method is proposed. Absolute encoder is used to achieve high resolution rotor position signal. MCU collects position signal from encoder, and The position information is transmitted to the master controller DSP via the Controller Area Network (CAN) bus. The experimental results show that the position detecting method meet the requirement of high-precision and real-time function of high-performance SRM drive.

The Target Vehicle Movement State Estimation Method with Radar Based on Kalman Filtering Algorithm

In this paper, based on Kalman filtering algorithm, a method of target vehicle motion state radar estimation with radar (or lidar) is presented. The state equations is established based on rigid plane dynamics theory, and then with a Kalman filter to do radar data processing, the position, velocity and acceleration of the target vehicle can be estimated at the same time, so that to cover the shortage that acceleration information can not be gained with radar system. Through simulation and field tests it is verified that the detection accuracy of position and velocity of target vehicle is increasing, and the acceleration of target vehicle can be estimated effectively and accurately.

Research of the Precision Positioning Method for Electric Locomotive Automatic Control System

The operation control of coke oven electric locomotive is an essential component of automatic control of coking manufacture. It is the main problem that coking enterprises should deal with in order to ensure the safety of production. In order to change and improve the actuality of manual driving, low positioning precision, high labor intensity and low producing efficiency, this paper proposes a practical and reliable automatic control scheme of electric locomotive based on successful experiences domestic and oversea.This scheme solves the key problem of electric locomotive automatic control-precision positioning, which containes a three-laser contraposition sensor and a positioning and lightproof piece used to ensure the accuracy of parking position detection, and a segmented deceleration control method used to ensure the automatism of parking brake. According to calculations and analysis, it is shown that the scheme could meet the system precision positioning requirements.

Research of PMSM Rotor Absolute Position Detection System Based on AU6802N1

Permanent magnet synchronous motor (PMSM) has the advantages such as high power density, simple structure and easy to maintain in the field of hybrid vehicle drive, and has been widely used in many areas. PMSM control methods include Space Vector Pulse Width Modulation (SVPWM), Direct Torque Control (DTC) and Maximum Torque per Current (MTPA) and so on. In these control methods, speed and accuracy of PMSM rotor absolute position detection is the key of its perfect control. The rotor absolute position information is more accurate, the amplitude of its torque ripple will be lower, which means better performance of PMSM control. In this paper, a PMSM rotor absolute position detection system based on AU6802N1 has been designed and produced, and laid a solid foundation for its calibration and improvement.

Development of Automatic 3D Blood Vessel Search and Automatic Blood Sampling System by Using Hybrid Stereo-Autofocus Method

We developed an accurate three-dimensional blood vessel search (3D BVS) system and an automatic blood sampling system. They were implemented into a point-of-care system designed for medical care, installed in a portable self-monitoring blood glucose (SMBG) device. The system solves problems of human error caused by complicated manual operations of conventional SMBG devices. We evaluated its accuracy of blood-vessel position detection. The 3D BVS system uses near-infrared (NIR) light imaging and the stereo and autofocus hybrid method to determine blood vessel locations accurately in three dimensions. We evaluated the accuracy of our 3D BVS system using a phantom of human skin, blood vessels, and blood. Additionally, we established an automatic blood sampling system for SMBG and assessed its performance in relation to punctures, blood suction, transport, and discharge on an enzyme sensor. The 3D BVS and automatic blood sampling system are adequate for use in a portable SMBG device.

Position detection accuracy of a novel linac-mounted intrafractional x-ray imaging system

The authors have developed a system that monitors intrafractional target motion perpendicular to the treatment beam with the aid of radioopaque markers by means of separating kV image and megavoltage (MV) treatment field on a single flat-panel detector. They equipped a research Siemens Artiste linear accelerator (linac) with a 41 × 41 cm(2) a-Si flat-panel detector underneath the treatment head. The in-line geometry allows kV (imaging) and MV (treatment) beams to share closely aligned beam axes. The kV source, usually mounted directly across from the flat-panel imager, was retracted toward the gantry by 13 cm to intentionally misalign kV and MV beams, resulting in a geometric separation of MV treatment field and kV image on the detector. Two consecutive images acquired within 140 ms (the first with MV-only and the second with kV and MV signal) were subtracted to generate a kV-only image. The images were then analyzed "online" with an automated threshold-based marker detection algorithm. They employed a 3D and a 4D phantom equipped with either a single radioopaque marker or three Calypso beacons to mimic respiratory motion. Measured room positions were either cross-referenced with a phantom voltage signal (single marker) or the Calypso system. The accuracy of the back-projection (from detected marker positions into room coordinates) was verified by a simulation study. A phantom study has demonstrated that the imaging framework is capable of automatically detecting marker positions and sending this information to the tracking tool at an update rate of 7.14 Hz. The system latency is 86.9 ± 1.0 ms for single marker detection in the absence of MV radiation. In the presence of a circular MV field of 5 cm diameter, the latency is 87.1 ± 0.9 ms. The total RMS position detection accuracy is 0.20 mm (without MV radiation) and 0.23 mm (with MV). Based on the evaluated motion patterns and MV field size, the positional accuracy and system latency indicate that this system is suitable for real-time adaptive applications.

Designing of Solar Cell Panel Sun Chasing System on Basis of MSP430 Micropower Single Chip Microcomputer

The system uses MSP430 micropower single chip microcomputer as controller and data processing chip in order to improve power generation efficiency of solar panel. Sunlight analog quantity measured by sensor is sampled by AD with skillful using of circular array light sensor to determine sunlight position on basis of obtained coding. Therefore, 2 steering engines can seek sunlight in 2 free degrees and make solar cell panel to generate the maximum output generation by pointing at direct sunshine position. Meanwhile, application of adaptive algorithm helps to improve detection accuracy of sunlight position. This essay focuses on discussing hardware realization method and software algorithm for accurate positioning of sun chasing system.

TU-C-214-08: Position Detection Accuracy of a Novel Linac-Mounted Intra-Fractional X-Ray Imaging System

Purpose: We have developed a system that monitors intra‐fractional target motion perpendicular to the treatment beam with the aid of metallic markers by means of separating kV image and MV treatment field on a single flat‐ panel detector. Methods: We equipped a research Siemens Artiste linac with a 41×41cm2 a‐Si flat‐panel detector underneath the treatment head. The inline geometry allows kV (imaging) and MV (treatment) beams to share closely aligned beam axes. The kV source, usually mounted directly across from the flat‐panel imager, was retracted towards the gantry by 13cm to intentionally misalign kV and MV beams, resulting in a geometric separation of MV treatment field and kV image on the detector. Two consecutive frames acquired within 140ms (the first with MV‐only and the second with kV and MV) were subtracted to generate a kV‐only image. The images were then analyzed ‘online’ with an automated threshold‐based marker detection algorithm. We employed a 2D phantom equipped with either a single metallic marker or three Calypso beacons to mimic respiratory motion. Measured room positions were either cross‐referenced with a phantom voltage signal (single marker) or the Calypso system. Results: A phantom study has demonstrated that our imaging framework is capable of automatically detecting marker positions and sending this information to our tracking tool at an update rate of 7.14Hz. The system latency is 111.35+/−2.6ms for single marker detection in the absence of MV radiation. In the presence of a 7×7cm2 300MU/min MV field, the latency increases to 117.23+−12.57ms. The position accuracy is −0.19+/−0.21mm (without MV radiation) and −0.26+/−0.27mm (with MV). The detection of three markers increased latency by 10–15ms. Conclusions: Positional accuracy and system latency strongly indicate that this system is suitable for real‐time adaptive applications. In the future, we hope to utilize the full imageinformation and substitute metallic with anatomical markers. Supported by Siemens Healthcare/CR.

Active beam position stabilization of pulsed lasers for long-distance ion profile diagnostics at the Spallation Neutron Source (SNS)

A high peak-power Q-switched laser has been used to monitor the ion beam profiles in the superconducting linac at the Spallation Neutron Source (SNS). The laser beam suffers from position drift due to movement, vibration, or thermal effects on the optical components in the 250-meter long laser beam transport line. We have designed, bench-tested, and implemented a beam position stabilization system by using an Ethernet CMOS camera, computer image processing and analysis, and a piezo-driven mirror platform. The system can respond at frequencies up to 30 Hz with a high position detection accuracy. With the beam stabilization system, we have achieved a laser beam pointing stability within a range of 2 μrad (horizontal) to 4 μrad (vertical), corresponding to beam drifts of only 0.5 mm × 1 mm at the furthest measurement station located 250 meters away from the light source.

Noncontact common-path Fourier domain optical coherence tomography method for in vitro intraocular lens power measurement

We propose a novel common-path Fourier domain optical coherence tomography (CP-FD-OCT) method for noncontact, accurate, and objective in vitro measurement of the dioptric power of intraocular lenses (IOLs) implants. The CP-FD-OCT method principle of operation is based on simple two-dimensional scanning common-path Fourier domain optical coherence tomography. By reconstructing the anterior and posterior IOL surfaces, the radii of the two surfaces, and thus the IOL dioptric power are determined. The CP-FD-OCT design provides high accuracy of IOL surface reconstruction. The axial position detection accuracy is calibrated at 1.22 μm in balanced saline solution used for simulation of in situ conditions. The lateral sampling rate is controlled by the step size of linear scanning systems. IOL samples with labeled dioptric power in the low-power (5D), mid-power (20D and 22D), and high-power (36D) ranges under in situ conditions are tested. We obtained a mean power of 4.95/20.11/22.09/36.25 D with high levels of repeatability estimated by a standard deviation of 0.10/0.18/0.2/0.58 D and a relative error of 2/0.9/0.9/1.6%, based on five measurements for each IOL respectively. The new CP-FD-OCT method provides an independent source of IOL power measurement data as well as information for evaluating other optical properties of IOLs such as refractive index, central thickness, and aberrations.

Effects of Crystal Pixel Size and Collimator Geometry on the Performance of a Pixelated Crystal -Camera Using Monte Carlo Simulation

Dedicated γ-cameras based on pixelated scintillators have long been used for breast tumor imaging. Intercrystal scattering (ICS) increases the background counting rate and degrades the image quality when small crystal pixels are used. Because of the small size of applied collimators, scattered radiation and septal penetration are high, and therefore collimator characteristics must be carefully considered. In our study, we investigated the influence of ICS events on position-detection accuracy (PDA) for pixelated crystals and the effects of different geometries of hexagonal-hole collimators on the performance of these cameras, using Monte Carlo simulation to optimize camera design. The arrays of thallium-doped cesium iodide detectors with different pixel dimensions that had been exposed to 140-keV photons of isotropic point source, 50 mm from the collimator surface, were simulated. Hexagonal-hole collimators were 10.5, 15, and 21 mm long. The septal thickness varied from 0.1 to 0.5 mm, with 3 different hole diameters. The results confirmed that by increasing the crystal pixel size, ICS was decreased and change of detection efficiency was negligible, but PDA, contrast-to-noise ratio, and spatial resolution (full width at half maximum) were increased. Our experiences confirmed that 2 × 2 mm was an optimum crystal pixel size, especially for a lower ICS fraction and an appropriate full width at half maximum. Because collimators are the limiting factor for spatial resolution and sensitivity, careful collimator design is of great importance.

Combination of optical shape measurement and augmented reality for task support: I. Accuracy of position and pose detection by ARToolKit

The introduction of information technology in manufacturing can provide valuable support. As such, we have developed a method for supporting a plate bending process that incorporates a line heating method that combines optical shape measurement and an augmented reality (AR) system using a head-mounted display. The accuracy of optical tracking using a fiducial marker is important for such a system. Experiments were conducted to clarify the position and pose errors of a marker detected by the AR system. Marker detection was performed using the ARToolKit software library. Systematic errors caused by misreading a marker edge were theoretically analyzed, and the direction dependence of the experimental errors was found to be well described.

SU-GG-BRC-03: Real Time 3D Tracking of the HDR Source Using Flat Panel Detector

Purpose: This is a proof of concept study with the objective of reconstructing the position of an HDR source in 3D in real‐time using a flat panel detector(FPD). It can potentially become the new standard in Quality Assurance (QA) for treatment delivery. Method and Materials: A matrix of markers (Ball Bearings 4mm in diameter) with precisely known locations was mounted on the cover of a flat panel detector(Acuity, Varian Inc) at variable height. Images acquired with the x‐ray source were used to calibrate the system. A plan with three dwell positions, well defined in 3D was created and delivered. Images were acquired with the FPD during the delivery of ‘treatment’. In house software was created to automatically segment and label the markers' images. A mathematical solution for the ‘near‐intersection’ of two 3D lines was implemented and used to determine the ‘true’ 3D source position. Each line was defined by the 3D positions of each marker and its projection on the FPD. A matrix with N markers will produce N*(N‐1)/2 points of intersection and their mean will result in a more accurate source position. The HDR source was placed on a 5cm solid water to mimic the patient and the FPD was placed at distances varying from 50 to 70cm. Results: The best imaging geometry was determined and images of markers obtained with the HDR source (strength of 6.2Ci) were properly segmented at all distances. During delivery, the source was located at [0,0,50], [0.5,0,50] and [2.0, 0, 50]. The reconstructed positions were [0,0,50.130], [0.497,−0.008,50.106] and [1.984, −0.005,50.053] with a standard deviation of [0.027,0.019,0.115]cm. When intersecting lines in 3D, the mean shortest distance between any two lines was 0.025cm with standard deviation 0.016cm. Conclusion: We proved that the accuracy of source position detection in 3D using a FPD is sub‐millimeter.

Numerical Study on the Improvement of Detection Accuracy for a Wireless Motion Capture System

A detection technique having an accuracy of better than 1 mm is required for body motion analysis in the field of medical treatment. A wireless magnetic motion capture system is one such effective detection technique. We propose a candidate system using an LC resonant magnetic marker (LC marker). Previous studies have showed that the system is capable of repeatable position detection accuracy of better than 1 mm if the system has an adequate signal-to-noise (S/N ratio). However, there are some cases in which the detection results include unignorable errors because some approximations, e.g. a magnetic dipole assumption of the LC marker, are applied to solve the inverse problem to determine the position and orientation of the LC marker. Therefore, a numerical analysis is employed to realize a motion capture system having a high detection accuracy. To elucidate the problem of detection error, the influence of variations in the sizes of the LC marker and the pick-up coil are considered in the numerical simulation. After studying the analysis, the main cause of detection error is determined to be the size of the pick-up coil rather than the size of the LC marker. It was also is found that a pick-up coil measuring 10 mm in diameter with a wound coil width of 1 mm achieves a detection accuracy of better than 0.1 mm.

Occupant Position Recognition with Seat Surface Pressure Distributions and Support Vector Machines Classifier

In the intelligent airbag system, the detection accuracy of occupant position is the precondition and plays a vital role in controlling airbag detonation time and inflation strength during the crash. Through accurately analyzing the seat surface pressure distributions of different occupant sitting position and types, an occupant position recognition algorithm which purely uses occupant pressure distribution information measured by seat pressure sensors is presented with the method of support vector machine. The distribution samples with different occupant sitting positions and types are used to train and test the recognition algorithm, thus verifying its validity and accuracy.

2P2-E06 Augmented Realityを用いた作業支援II : ARToolKitによる位置・姿勢検出精度(VRとインタフェース)

2P2-E06 Augmented Realityを用いた作業支援II : ARToolKitによる位置・姿勢検出精度(VRとインタフェース)

Comparison of PM Motor Structures and Sensorless Control Techniques for Zero-Speed Rotor Position Detection

The rotor position of a synchronous permanent magnet (PM) motor can be detected by means of the injection of a high-frequency stator voltage superimposed to the fundamental component. Thanks to the rotor anisotropy, the corresponding high-frequency current is modulated and used to determine the rotor position. Two techniques are considered: the first one adopts a pulsating voltage vector in the estimated synchronous reference frame, while the second one adopts a rotating voltage vector. These techniques are effective at zero and at low motor speed. The accuracy of the rotor position detection depends strictly on the rotor saliency, that is, on the geometry of the PM rotor. In fact both saturation and d-and q-axis cross-coupling have a heavy influence on the correct rotor position detection. The aim of this paper is to compare the two sensorless control techniques, together with two rotor geometries, that is, IPM and inset rotor. In order to highlight the effectiveness of the sensorless technique, the tests are carried out at various operating conditions. It is found that the effectiveness of the sensorless rotor position detection strongly depends on the PM rotor geometry. Conversely, the choice of the sensorless control technique affects slightly the rotor position detection.

Development of cosmic-ray tracker for KASKA neutrino oscillation experiment

A cosmic-ray tracking system to trace the cosmic muon passage will be installed in the detector for the planned reactor-neutrino oscillation experiment KASKA. Background events due to isotopes produced in the spallation reaction by the cosmic muons can be estimated by their association to the cosmic-ray track. For this detector, we propose a scheme of a cosmic-ray tracker consisting of extruded plastic scintillators with wavelength-shifting fiber readout. It aims at an improvement of position uniformity, detection efficiency, and detection accuracy by using the time difference between both sides of scintillator bar. Some basic performances of prototype detector were measured by beam test at the 12-GeV Proton Synchrotron in High Energy Accelerator Research Organization (KEK).

1P1-D06 触覚GUIを可能とする視覚障害者用入出力装置の開発 : 第三試作機の開発

A basic device combining a tactile display function and a touch position/force direction sensing function is proposed. The first trial device consists of two major components, a tactile graphic display and a 6-axis force/torque sensor. The proposed device is substituted for the mouse function of a click and scrolling, and it provides a fundamental GUI operation. From the knowledge acquired from the first trial device, the new tactile input/output device which forcused on enlargement of tactile presentation area, the improvement in position detection accuracy, and improvement in easy-to-transport is developed. In this paper, we explain the structure of the device, and development of a 3-axis force sensor. Since the newly position detection principle is drawn with change of the device mechanism, we also illustrate the position detection method.

A center detection algorithm for Shack–Hartmann wavefront sensor

A modified center position detection algorithm of the spot image for the Shack–Hartmann wavefront sensor was experimentally investigated. The modified center of weight algorithm uses some power from the gray level intensity of the spot images instead of the gray level intensity itself. From the experiments, the repeatability and accuracy of the center position detection of the spot images which used the algorithm were improved when compared with those using the conventional center of weight algorithm. Applications of the algorithm to the measurement of the displacement of the spot images of the Shack–Hartmann wavefront sensor and the experimental results of the closed-loop wavefront correction are described in this paper.