Position Detection Error Research Articles

A Synchronous and Accurate Detection Method for Gas Pipeline Leakage Position and Flow Rate Based on Double Fiber Bragg Gratings

Fast and accurate detection of pipeline leaks plays an important role in reducing economic losses and ensuring the safety of personnel. However, for the two important indicators of gas pipeline detection, how to effectively detect the leakage location and leakage rate simultaneously is a serious challenge. In this paper, we present an innovative optical fiber detection method based on double fiber Bragg gratings (FBGs) string to solve this problem. Combined with the theory of material mechanics and fluid mechanics, the binary equations are derived as the demodulation formula. In the detection, the corresponding physical quantities can be calculated by substituting the center wavelength of the two FBGs after drift. The experiments demonstrate that this sensor’s gas flow rate sensitivity in different positions can be up to 466.67 pm∙s/m. Meanwhile, at the same flow rate and different leakage positions, the sensor has sensitive symmetrical performance. The error results manifest that the velocity error is not more than 0.13 m/s, and the relative position detection error is not more than 0.167%. Overall, besides the extended measurement range and excellent linearity, our method also has the advantages of low production cost, simple structure and ease of production, which is more suitable for gas pipeline health monitoring in the future.

位置センサ付き超多極・永久磁石同期モータ向け電流脈動抑制制御

Permanent magnet synchronous motors (PMSMs) are employed in numerous applications as high-power-density and highly efficient drive sources. Notably, multipole PMSMs are key in achieving high output densities for PMSMs. However, multipole PMSMs decrease the sensor resolution and increase the error. In this study, we developed a control technology to reduce the position detection error of a resolver with a specific frequency for a PMSM drive system with a position sensor and verified its effect with HILS and through an experiment.

A Large-Area Flexible Tactile Sensor for Multi-Touch and Force Detection Using Electrical Impedance Tomography

For large area robot skin design, the distribution of rigid components and wires in traditional array sensors leads to the decrease of the flexibility and extensibility of sensors. The flexible sensors based on non-invasive electrical impedance tomography (EIT) can avoid these shortcomings. However, design of a large-area flexible tactile sensors using EIT technique is still challenging due to the tradeoff between manufacturability and spatial resolution. In this study, we proposed a novel non-array EIT-based tactile sensor which is made of a porous elastic polymer and ionic liquid. The sensor free from internal array electrodes is straightforward to manufacture and can cover a large area with low cost. To improve the spatial resolution and touch sensitivity, we adopted a deep learning scheme Pyramid Scene Parsing Network (PSPNet) to postprocess the originally reconstructed images to enhance the sensor tactile perception. With this data-driven method, we achieved a single-point position detection error of 7.5± 4.5 mm without using internal electrodes. To overcome the location dependency of EIT sensing problems, we proposed a method of sub-regional fitting to calibrate the distributed forces for the large-area flexible tactile sensor and obtained a quantitative relationship between the touch force and EIT measurement for the entire sensing area for continuous sensing. The real-time performance of the proposed prototype sensor system demonstrated that we can achieve more accuracy of multi-touch and distributed force detection on the non-array sensors with a temporal resolution of about 1.3 frames/sec for potential applications in human-robot interfaces.

Visual Collaboration Leader-Follower UAV-Formation for Indoor Exploration.

UAVs operating in a leader-follower formation demand the knowledge of the relative pose between the collaborating members. This necessitates the RF-communication of this information which increases the communication latency and can easily result in lost data packets. In this work, rather than relying on this autopilot data exchange, a visual scheme using passive markers is presented. Each formation-member carries passive markers in a RhOct configuration. These markers are visually detected and the relative pose of the members is on-board determined, thus eliminating the need for RF-communication. A reference path is then evaluated for each follower that tracks the leader and maintains a constant distance between the formation-members. Experimental studies show a mean position detection error (5 × 5 × 10cm) or less than 0.0031% of the available workspace [0.5 up to 5m, 50.43° × 38.75° Field of View (FoV)]. The efficiency of the suggested scheme against varying delays are examined in these studies, where it is shown that a delay up to 1.25s can be tolerated for the follower to track the leader as long as the latter one remains within its FoV.

IoMT-Enabled Fusion-Based Model to Predict Posture for Smart Healthcare Systems

Smart healthcare applications depend on data from wearable sensors (WSs) mounted on a patient’s body for frequent monitoring information. Healthcare systems depend on multi-level data for detecting illnesses and consequently delivering correct diagnostic measures. The collection of WS data and integration of that data for diagnostic purposes is a difficult task. This paper proposes an Errorless Data Fusion (EDF) approach to increase posture recognition accuracy. The research is based on a case study in a health organization. With the rise in smart healthcare systems, WS data fusion necessitates careful attention to provide sensitive analysis of the recognized illness. As a result, it is dependent on WS inputs and performs group analysis at a similar rate to improve diagnostic efficiency. Sensor breakdowns, the constant time factor, aggregation, and analysis results all cause errors, resulting in rejected or incorrect suggestions. This paper resolves this problem by using EDF, which is related to patient situational discovery through healthcare surveillance systems. Features of WS data are examined extensively using active and iterative learning to identify errors in specific postures. This technology improves position detection accuracy, analysis duration, and error rate, regardless of user movements. Wearable devices play a critical role in the management and treatment of patients. They can ensure that patients are provided with a unique treatment for their medical needs. This paper discusses the EDF technique for optimizing posture identification accuracy through multi-feature analysis. At first, the patients’ walking patterns are tracked at various time intervals. The characteristics are then evaluated in relation to the stored data using a random forest classifier.

2D Position-Sensitive Hybrid-Perovskite Detectors.

Hybrid organic-inorganic perovskites (HOIPs) have emerged as a versatile class of semiconductors for numerous optoelectronic applications. Here, we demonstrate light-excitation-dependent two-dimensional (2D) position-sensitive detectors (PSDs) using a mixed-phase perovskite, FA0.83Cs0.17Pb(I0.9Br0.1)3, as the active semiconductor, incorporated within a five-terminal device geometry. The light-induced lateral photovoltage, which is initiated by selective charge transfer across the metal-perovskite barrier interface, is utilized to achieve the excitation-position-dependent electric response. The 2D PSD devices exhibit a spatially dependent linear variation of the photosignal with sensitivity >50 μV mm-1 and a low position detection error (1-2%), making them suitable for applications such as quadrant detectors. Further, it is observed that the device architecture plays a key role in controlling the dynamics and linearity of the HOIP PSDs. The large active area devices (up to ∼2 cm × 2 cm) exhibit a distinct spatial variation of the photosignal. We utilize the functionality of the PSD device for light-tracking applications by implementing a continuous detection scheme.

Development of solar cell for large area position detection: proof of concept

Detecting and analyzing a moving body position are helpful in many fields, such as medicine, sports performance, virtual reality and many more. Therefore, researchers try to develop a tool or a system that helps to detect the motion and tracking its position. This paper shows how a Si solar cell can be modified to function as a Position Sensitive Detector (PSD), which could be used as a large area detector in a position detection system. To develop the new detector, we modeled and simulated the modified solar cell by TCAD simulation tools to calculate the detected photocurrent as a function of the position of an incident laser beam sourced by the moving object. Further, an optical position detection system is implemented containing the modified solar cell, a signal amplifier and a microcontroller. The output is then displayed on a Laptop. By measuring the same simulated output photocurrents, it is found that the measured system output matches the simulation results. This proposed position detection system is relatively cheap because it does not contain high precision optical image building components such as lenses and mirrors. Besides, the proposed system could substitute the optical system by using a large area PSD made from a broad array of solar cells. The electronics are also much more straightforward than those in systems based on image processing. So, it has a high-speed response. The error assessment of the proposed system showed a low position detection error of less than 10%.

Position and Speed Detection Method Based on Cross-Decoupling Network Filtering for Gearless Traction Motor Drives at Low-Speed Operation

This article proposes a position and speed detection method based on the cross-decoupling network filtering (CDNF) method combined with phase-locked loop (PLL). This method is used to enhance the detection precision of position and reduce the speed fluctuations at low-speed operation for gearless traction motor drives with an ordinary-resolution encoder. The harmonic distributions of the discontinuous orthogonal position signal in low-speed region are analyzed. On this basis, the position and speed detection method based on CDNF with PLL is presented to obtain the harmonics of the discontinuous position signal adaptively for eliminating the position detection error and improving the accuracy of the speed feedback. The criteria of the filter parameter design are presented based on the maximum phase margin theory to maintain the stability of the system. Experiments were carried out on an 11.7 kW permanent magnet gearless traction motor drive with an ordinary-resolution encoder installed. The experimental results verify the effectiveness of the proposed method at low-speed operation.

Online Extraction of Pose Information of 3D Zigzag-Line Welding Seams for Welding Seam Tracking.

Three-dimensional (3D) zigzag-line welding seams are found extensively in the manufacturing of marine engineering equipment, heavy lifting equipment, and logistics transportation equipment. Currently, due to the large amount of calculation and poor real-time performance of 3D welding seam detection algorithms, real-time tracking of 3D zigzag-line welding seams is still a challenge especially in high-speed welding. For the abovementioned problems, we proposed a method for the extraction of the pose information of 3D zigzag-line welding seams based on laser displacement sensing and density-based clustering point cloud segmentation during robotic welding. after thee point cloud data of the 3D zigzag-line welding seams was obtained online by the laser displacement sensor, it was segmented using theρ-Approximate DBSCAN (Density-Based Spatial Clustering of Applications with Noise) algorithm. In the experiment, high-speed welding was performed on typical low-carbon steel 3D zigzag-line welding seams using gas metal arc welding. The results showed that when the welding velocity was 1000 mm/min, the proposed method obtained a welding seam position detection error of less than 0.35 mm, a welding seam attitude estimation error of less than two degrees, and the running time of the main algorithm was within 120 ms. Thus, the online extraction of the pose information of 3D zigzag-line welding seams was achieved and the requirements of welding seam tracking were met.

A Method for Improving the Detection Accuracy of the Spot Position of the Four-Quadrant Detector in a Free Space Optical Communication System.

In a free space optical communication system, the beacon light will lose most of its energy after long-distance transmission, and the background light from the universe will strongly interfere with it. The four-quadrant detector (4QD) has been widely used in optical communication systems as a high-precision spot position detection sensor. However, if the light signal falling on the 4QD is too weak, the electrical signal of the output position will be very weak, and it will easily be affected by or even submerged in noise. To solve this problem, we propose a method for improving the spot position detection accuracy. First, we analyzed the solution relationship between the actual position of the spot and the output signal of the 4QD, with a Gaussian spot as the incident light model. The output current signal of the detector was then transimpedance-amplified by an analog circuit and the output voltage signal with noise was digitally filtered. An error compensation factor and the gap size of the detector were introduced into the traditional spot position detection model. High-precision spot position information for the 4QD in a complex environment was then obtained using the improved spot position detection model. Experimental results show that the maximum spot position detection error for this method was only 0.0277 mm, and the root mean square error was 0.0065 mm, when the 4QD was in a high background noise environment. The spot position detection accuracy was significantly improved compared with traditional detection algorithms. Real-time detection can therefore be achieved in practical applications.

Investigation of high-precision algorithm for the spot position detection for four-quadrant detector

In this paper, we propose a new polynomial fitting algorithm to improve the spot position detection accuracy based on four-Quadrant Detector (4QD) when the circular spot with Gaussian energy is used as the incident light model. The traditional polynomial fitting method is difficult to ensure high spot position detection accuracy in a wide detection range. To solve this problem, we analyze and compare the characteristics of different algorithms for spot position detection, and consider the influence of the 4QD gap size in the model. Based on the initial solution of the geometric approximation method, we introduce the error compensation factor function, a new spot position detection model is designed. The results of simulation and experiment show that the new algorithm can greatly reduce the position detection error of 4QD for Gaussian spot. When the radius of incident spot is 0.5 mm and within the detection range of [-0.5 mm∼0.5 mm], the maximum error is 0.001353 mm and the root-mean-square error is 0.0004596 mm with the new five-order polynomial fitting algorithm which are reduced 56.7% and 69.7% than traditional nine-order polynomial fitting algorithm. Moreover, the computational complexity of the new algorithm is much less than traditional algorithm and the new algorithm also has good prospects in laser communication, high energy laser weapons or others.

다중 자기센서를 이용한 실내 자기 지도 기반 보행자 위치 검출 정확도 향상 알고리즘

This research proposes a indoor magnetic map matching algorithm that improves the position accuracy by employing multiple magnetic sensors and probabilistic candidate weighting function. Since the magnetic field is easily distorted by the surrounding environment, the distorted magnetic field can be used for position mapping, and multiple sensor configuration is useful to improve mapping accuracy. Nevertheless, the position error is likely to increase because the external magnetic disturbances have repeated pattern in indoor environment and several points have similar magnetic field distortion characteristics. Those errors cause large position error, which reduces the accuracy of the position detection. In order to solve this problem, we propose a method to reduce the error using multiple sensors and likelihood boundaries that uses human walking characteristics. Also, to reduce the maximum position error, we propose an algorithm that weights according to their importance. We performed indoor walking tests to evaluate the performance of the algorithm and analyzed the position detection error rate and maximum distance error. From the results we can confirm that the accuracy of position detection is greatly improved.

Rotor-Position Detection in Permanent-Magnet Wheel Motor to Ensure Smooth Startup From Standstill

In this paper, an innovative rotor-position-detection method for a permanent-magnet wheel motor (PMWM) that operates from standstill to low speed is presented. The neutral voltage, which is sensed through phaseshifted pulse width modulation, overcomes the limitations of the conventional back electromotive force (EMF)-based position-detection method, which is more suitable for high-speed operation. In addition, a technique that ensures a transition between the two position-detection methods is presented to cover the full speed range. Computer simulations are employed to design and assess the neutral-voltage-based and EMF-based position-detection methods. The results of the position detection and angle error are presented starting from standstill to low speed. A step current (iq) corresponding to motor torque demand is applied for the starting process in the two position-detection methods. The experimental studies of the new position-detection method are conducted. The method is successfully applied to drive a 60-kW PMWM that operates from standstill to high speed. This demonstrates the effectiveness and performance of the presented method.

An Automatic Recognition and Positioning Method for Point Source Targets on Satellite Images

Currently, the geometric and radiometric calibration of on-board satellite sensors utilizes different ground targets using some form of manual intervention. Point source targets provide high precision geometric and radiometric information and have the potential to become a new tool for joint geometric and radiometric calibration. In this paper, an automatic recognition and positioning method for point source target images is proposed. First, the template matching method was used to effectively reduce nonpoint source target image pixels in the satellite imagery. The point source target images were then identified using particular feature parameters. Using the template matching method, the weighted centroid method, and the Gaussian fitting method, the positions of the centroid of the point source target images were calculated. The maximum position detection error obtained using the three methods was 0.07 pixels, which is comparably better than artificial targets currently in use. The experimental results show point source targets provide high precision geometric information, which can become a suitable alternative for automatic joint geometric and radiometric calibration of spaceborne optical sensors.

Scheme based on buck‐converter with three‐phase H‐bridge combinations for high‐speed BLDC motors in aerospace applications

High reliability and safety are critical in aerospace applications. This study introduces a novel high-reliable inverter scheme based on buck-converter with three-phase H-bridge combinations and a high-accurate commutation instant shift correction method for high-speed brushless direct current (BLDC) motors. First, the traditional three-phase inverter and buck-converter-based BLDC motor drive system are analysed. Second, the zero-crossing points of back-electromotive force detection circuit are designed and the position detection error is analysed. Third, a speed measurement with enhanced detection frequency and accuracy is proposed. Then, a fast two-stage commutation instant shift compensation method is designed based on the unique speed measurement method. High-reliable and accurate commutations are achieved especially in the high-speed steady state, which improves the speed control precision and decreases the motor driving loss. Finally, the control system design process is proposed and a fault-tolerant-control strategy is presented to enhance the reliability of the system. Experimental results illustrate the effectiveness and practicability of the proposed inverter scheme and the position sensorless control method.

Gridded duo‐lateral position sensitivity detector with high linearity to low energetic electrons in vacuum environment

Characterising a position sensitive detector in a vacuum environment without beam position monitoring devices can be challenging and expensive. With this in mind, the authors have designed and fabricated a duo-lateral position sensitive detector (PSD) incorporated with simple and inexpensive surface features. It was evaluated using scanning electron microscopy. To assist in pinpointing precise positioning as well as acting as path guide during the sweeping of electrons, multiple grids were lithographically patterned on the top layer of the duo-lateral PSD. By sweeping electrons along two axes of the detector, the position detection error of both axes was determined from the signals recorded using a transimpedance amplification circuit. They were able to characterise the linearity over the x - and y -axis of the PSD and the results show a very high linearity over two-dimensions of the PSD's active area and that accurate beam monitoring for spectroscopic measurement without additional beam position monitoring devices is possible.

Power spectral analysis for optical trap stiffness calibration from high-speed camera position detection with limited bandwidth

The use of camera imaging enables trap calibration for multiple particles simultaneously. For stiff traps, however, blur from image integration time affects the detected particle positions significantly. In this paper we use power spectral analysis to calibrate stiff optical traps, taking the effects of blur, aliasing and position detection error into account, as put forward by Wong and Halvorsen [Opt. Express 14, 12517 (2006)]. We find agreement with simultaneously obtained photodiode data and the expected relation of corner frequency fc with laser power, up to fc = 3.6 kHz for a Nyquist frequency of 1.25 kHz. Spectral analysis enables easy identification of the contribution of noise. We demonstrate the utility of our approach with simultaneous calibration of multiple holographic optical traps.

Simultaneous PES Generation, Timing Recovery, and Multi-Track Read on Patterned Media: Concept and Performance

This paper presents new work on the performance of the method for simultaneously detecting the position and timing error in bit patterned media (BPM). The regular spatial arrangement of bits in BPM allows position information and timing information to be extracted from the data. Our method exploits interference between adjacent tracks by employing a read head wider than the track pitch. The method also provides the capability of reading data from two tracks at the same time. Here we employ a more realistic read head field and more realistic shapes of the bit islands in simulations than in prior work. We determine the sensitivity of the position detection, timing recovery, and bit error rate of the method to manufacturing variations in the locations and sizes of bits.

Position and orientation detection of capsule endoscopes in spiral motion

In this paper, a position and orientation detection method for the capsule endoscopes devised to move through the human digestive organs in spiral motion, is introduced. The capsule is equipped with internal magnets and flexible threads on their outer shell. It is forced to rotate by an external rotating magnetic field that produces a spiral motion. As the external magnetic field is generated by rotating a permanent magnet, the 3-axes Cartesian coordinate position and 3-axes orientation of the capsule endoscopes can be measured by using only 3 hall-effect sensors orthogonally installed inside the capsule. However, in this study, an additional hall-effect sensor is employed along the rotating axis at a symmetrical position inside the capsule body to enhance measurement accuracy. In this way, the largest position detection error appearing along the rotating axis of the permanent magnet could be reduced to less than 15mm, when the relative position of the capsule endoscope to the permanent magnet is changed from 0mm to 50mm in the X-direction, from −50mm to +50mm in the Y-direction and from 200mm to 300mm in the Z-direction. The maximum error of the orientation detection appearing in the pitching direction ranged between −4° and +15°.

Stretching Single DNA Molecules and using High-Speed Camera Power Spectral Analysis to Demonstrate High Force Capabilities of Holographic Optical Tweezers

Holographic optical tweezers (HOTs), in which a Spatial Light Modulator is used to change the phase pattern of the laser light, enable the manipulation in three dimensions of many particles simultaneously. This can be used for the probing of extended structures such as cells and extended protein networks. To allow for quantitative force measurements, the HOT traps need to be calibrated. However, nanometer-scale position modulations are introduced by the Spatial Light Modulator. In power spectral analysis, modulations at specific frequencies and drift can be readily identified in the spectrum and omitted before analysis, making this the preferred method of calibration for our HOTs. We use high-speed camera imaging for position detection of multiple trapped particles simultaneously, from which we obtain power spectra with 1.25 kHz bandwidth. For stiff traps, however, blur due to image integration time affects the detected particle positions significantly. Taking the effects of blur, aliasing and position detection error into account, as put forward by Wong and Halvorsen [Opt. Express 14, 12517, 2006], we are able to obtain the corner frequency fc of the power spectrum for stiff traps with fc up to 3.5 kHz. We demonstrate the utility of our calibration approach by measuring the force-extension curve for 4-micrometer-long DNA.