实时测温系统中测温精度的提高措施

在介绍一种利用InGaAs/I半导体激光器实现的实时测温系统的基础上,着重从硬、软两方面研究了在该系统中所采取的提高其温度测量精度的若干措施:一是精选探测器、优化设计调制盘并进行选频放大;二是在调制盘与探测器之间置一窄带滤光片;三是采用水冷遮蔽板并进行电气补偿;四是提高系统的采样精度。进行了一些必要的分析和讨论。     

Surface plasmon excitation in fiber-optics sensors: a noveltheoretical approach

A theoretical method for the study of surface plasmon excitation in metallic layers, as used in fiber-optics sensors, is presented. It is based in the calculation of the propagated fields in the waveguide structure and allows us to compute the loss of optical power in the fiber (which is the measured parameter) from energy conservation considerations. The agreement with experimental data obtained with real sensors is good. The method is conceptually simple and can be adapted to different configurations of the sensors     

Enhancing the audience experience during sport events: real-time processing of multiple stereoscopic cameras

From video acquisition to 3D rendering, most of the hardware and software modules required for stereoscopy are currently available in academic or industrial R&D laboratories. Some are even features of open-source libraries. However, designing a stereoscopic architecture able to perform this acquisition followed by geometrical calibration and colour correction, disparity maps computation, multi-view coding and transmission for several cameras into one dedicated server remains a challenge. This was achieved for the SkyMedia project which aimed at providing an enhanced experience for the audience, organising staff and performers of an event. Compromises were required, from lower-resolution depth estimation to limited MultiView Coding predictions, but in the end the project system was fit to the task and delivered contents to the various people evolving around the 2012 Turin Marathon.     

Design of a hardware accelerator for real-time moment computation:a wavefront away approach

In image processing, pattern recognition, and computer vision, one of the most powerful techniques for feature extraction is to use moments. Real-time applications of this method, however, have been prohibited due to the intensive computation encountered in calculating the moments. One solution to this problem is to adopt specially designed hardware accelerators. This paper describes, from a practical standpoint, the design of a custom hardware accelerator for speeding up the moment computation. The design of the core functional units and the design of the overall system based on a wavefront array architecture are discussed. The moment accelerator can be easily configured into different sizes to meet diverse application requirements cost effectively. Testing results based on implementation using field-programmable gate array devices show that, at an affordable cost, the proposed hardware accelerator can deliver real-time speeds for moment computation. Elimination of this computational bottleneck makes it possible to use moments-based features in real-time industrial applications     

Parallel and local feature extraction: a real-time approach to roadboundary detection

Presents a system for the extraction of road boundaries from an image taken in an out-of-town environment. In this application, computational speed and performance play a fundamental role in the selection of the hardware platform and the design of algorithms. The algorithm has been designed to be implemented on a special-purpose mesh-connected SIR ID architecture, PAPRICA, which will be fitted to the vehicle. This presentation focuses on the algorithms and in particular on processing speed.     

MEMS传感器的应用走势及提高精度的方法探讨

近日,ST(意法半导体)大中华暨南亚区模拟和MEMS产品部市场总监吴卫东先生在京介绍了ST MEMS传感器的发展概况,提高传感器精度的方法,以及汽车、工业等市场对传感器的需求特点.     

Toward a decision informatics paradigm: a real-time, information-based approach to decision making

The focus of this paper is on decision making; more specifically, on what decision making requirements are needed in the future. We augur for a decision informatics paradigm; it is a real-time, information-based approach to decision making. The paradigm is supported by two sets of technologies (i.e., information and decision technologies) and underpinned by three disciplines (i.e., data fusion/analysis, decision modeling, and systems engineering). We begin by considering the context - and needs - for decision making as the economies of the world change and evolve, especially in regard to emerging services; then our proposed decision informatics paradigm is detailed and illustrated, together with an in-depth review of a critical, underpinning research area (dealing with real-time fusion and analysis of multiple nonhomogeneous data sources), followed by several concluding remarks.     

Noninvasive glucose sensing utilizing a digital closed-looppolarimetric approach

A polarimetric glucose sensor utilizing a digital closed-loop controller was designed and implemented during this study. Its potential as a noninvasive glucose sensor was evaluated in vitro for both glucose doped water and bovine aqueous humor mediums. A physiological hyperglycemic concentration range was used in both calibration and validation of each set of experiments. Ideally, the end application of this system could estimate blood glucose concentrations indirectly by measuring the amount of rotation of a light beam's polarization state after it propagates through the aqueous humor contained within the anterior chamber of the eye. The polarimeter designed in this study differs from similar investigated systems in that it utilizes a digital closed-loop control system. This type of controller was implemented in order to further improve system repeatability and stability without sacrificing accuracy. Unique to this investigation, independent validation sets other than those used to create each respective calibration model were obtained. The results of the glucose-doped water experiments yielded mean standard errors of prediction for calibration and validation of 6.91 and 8.84 mg/dl, respectively. The mean standard errors of prediction during calibration and validation of the glucose-doped aqueous humor experiments were higher at 27.20 and 27.47 mg/dl, respectively, due to medium degradation over time while exposed to air     

机载三维成像激光雷达实时探测精度分析

为了提高机载增益调制型三维成像激光雷达系统实时探测时的测距精度,推导了该激光雷达的测距公式,可以得出距离精度与探测器探测到的光强密切相关,机载实时探测时各种运动引起的像移会通过强度图来影响测距精度和成像质量。基于光学成像原理和坐标变换矩阵原理,分析了该激光雷达实时探测时飞行器姿态变化对成像质量的影响,分析结果显示,飞行器姿态变化对z方向的位移影响最大为0.0298个像素,可以忽略不计,而对x,y方向像移影响比较大。研究了飞行器同一个姿态变化对地面点的像移影响,研究结果表明,像移会随着地面物点对光轴的夹角和飞行方向的夹角改变而改变。     

实时测温系统中采样精度的提高措施

在介绍一种利用InGaAs/I半导体激光器并采用钽酸锂热释电探测器实时测量比辐射率及温度的系统的基础上,着重讨论了从光、电干扰及其抑制这两方面所采取的提高其采样精度的措施：一是在抑制光干扰的基础上选择合适的采样时机并优选采样结果;另一是在抑制电干扰的基础上选择合适的采样周期并进行信号平均。给出了系统的采样硫程图,进行了一些必要的分析和讨论。     

Intelligent sensors: a functional view

This paper presents the generic model of intelligent instruments and specifies it for intelligent sensors, from a functional point of view, i.e., from the point of view of the services they offer to the system designer. Basic services are concerned with data estimation and data characterization, both based on local transducers and on the availability of remote signals. Advanced services are concerned with data validation, through fault detection and isolation procedures, and with fault tolerance, by means of accommodation and reconfiguration strategies. Finally, the integration of intelligent sensors in distributed control systems is discussed.     

Neural-based approach for localization of sensors in indoor environment

Location of wireless sensor nodes is an important piece of information for many applications. There are many algorithms present in literature based on Received Signal Strength (RSSI) to estimate the location. However the radio signal propagation is easily influenced by diffraction, reflection and scattering. Therefore algorithms purely based on RSSI may not accurately predict the position of the node. In the present work, an algorithm for estimating the position of mobile nodes is proposed which is based on a combination of Received Signal Strength (RSSI) and Link Quality Indicator (LQI). Artificial Neural Networks are used to establish the relationship between the location of the mobile node and the experimentally obtained values of RSSI and LQI. Two different algorithms namely, Bayesian Regularization and Gradient Descent are used to develop the neural network model. Proposed algorithms improve the localization accuracy and perform better than other state-of-the-art algorithms.     

Enhancing localization accuracy of collaborative cognitive radio users by internal noise mitigation

Location information of mobile primary users is one of the essential requirements for an underlay cognitive radio user to utilize the licensed spectrum efficiently. The performance of various location-based applications such as global navigation satellite system, device to device communication in dense urban 5G network also depends on the localization accuracy. In this paper, a collaborative localization scheme based on received signal strength has been proposed. The weighted centroid localization algorithm has been applied in the proposed network scenario to compute location coordinates of the mobile primary user. Since the channel noise effects are random and unavoidable, this paper has focused on the mitigation of the internal noise by designing a suitable reconfigurable FIR filter after the demodulator stage of a cognitive radio receiver circuit to improve precision of signal measurement during primary user localization. The localization error rate has come down to (1.3–1.62) % after internal noise mitigation. The enhancement in the localization accuracy improves the overall spectrum utilization efficiency and reduces the miss detection and false detection probabilities in the proposed underlay network.

     

Enhancing kinematic accuracy of redundant wheeled mobile manipulators via adaptive motion planning

An increasing demand for wheeled mobile manipulators (WMMs) in fields that require high precision tasks has introduced new requirements as far as their kinematic accuracy. A WMM consists of a manipulator mounted on a mobile base. This configuration usually makes the WMM a redundant robotic system. One limiting factor is that the kinematic accuracy of the mobile base is often lower than that of the manipulator because of modeling errors and disturbances such as slippage. Thus, it makes sense to distribute more of a given set of motion requirements for the entire mobile manipulator to the manipulator when possible — this is usually done using a weighting matrix that sums the mobile base motion and the manipulator motion. In this paper, considering a redundant WMM, a novel adaptive motion planning method is proposed as a secondary objective in the null space of the primary objective (improvement of the WMM’s kinematic accuracy) for the WMM. Also, a tertiary objective to move the manipulator away from its singularity is proposed. This objective is activated if the secondary objective is feasible and the WMM still has remaining redundant degrees of freedom. The proposed method is implemented at the acceleration level to circumvent the discontinuity of the commanded joint velocity due to the adaptive motion planning algorithm. The advantages and effectiveness of the proposed approach are demonstrated with a traditional motion planning approach through experiments.     

New approach for the low-speed operation of PMSM drives withoutrotational position sensors

A new approach to the position sensor elimination of permanent magnet synchronous machine (PMSM) drives for low-speed operation is presented in this paper. Using the position sensing characteristics of the PMSM itself, the actual rotor position, as well as the machine speed, can be obtained even in the transient state. Since the essential back-EMF information is obtained from direct measurement during a special test cycle called MCDI, the operating speed range of the sensorless drives can be extended to 10 RPM. Moreover, the chronic starting problem of PMSM drives can be simply settled by the proposed algorithm. In order to verify the feasibility of the proposed scheme, experimental results in the low-speed range of about 10~100 RPM are also presented     

Schedulability analysis of real-time traffic in WorldFIP networks: an integrated approach

The WorldFIP protocol is one of the profiles that constitute the European fieldbus standard EN-50170. It is particularly well suited to be used in distributed computer-controlled systems where a set of process variables must be shared among network devices. To cope with the real-time requirements of such systems, the protocol provides communication services based on the exchange of periodic and aperiodic identified variables. The periodic exchanges have the highest priority and are executed at run time according to a cyclic schedule. Therefore, the respective schedulability can be determined at pre-run-time when building the schedule table. Concerning the aperiodic exchanges, the situation is different since their priority is lower and they are bandied according to a first-come-first-served policy. In this paper, a response-time-based schedulability analysis for the real-time traffic is presented. Such analysis considers both types of traffic in an integrated way, according to their priorities. Furthermore, a fixed-priorities-based policy is also used to schedule the periodic traffic. The proposed analysis represents an improvement relative to previous work and it can be evaluated online as part of a traffic online admission control. This feature is of particular importance when a planning scheduler is used, instead of the typical offline static scheduler, to allow online changes to the set of periodic process variables.     

Effects of the surface morphologies of ZnO nanotube arrays on the performance of amperometric glucose sensors

Amperometric glucose sensors have been fabricated with glucose oxidase (GOx) immobilized on ZnO nanotubes (ZnONTs) by physical adsorption. The ZnONTs were formed through selective dissolution of ZnO nanorods (ZnONRs) which were hydrothermally synthesized on Au cylindrical spiral (AuCS) electrodes. With the etching temperature regulated, the surface morphologies of the ZnONT arrays were tailored and their effects on the performance of the corresponding glucose sensors were investigated. It is found that at 65 °C the as-prepared ZnONT arrays show a Gaussian rough surface with larger surface area and better hydrophilicity, and have an effective solid–liquid interface with GOx solution, which further results in desirable GOx immobilization. Therefore favorable performance of the ZnONT-based glucose sensor was obtained, such as the sensitivity 2.63 μA/(mM cm²), linear range 0–6.5 mM, low detection limit 8 μM (S/N=3) and Michaelis-Menten constant 5.24 mM, which are superior to that of the ZnONR-based one. Moreover, the ZnONT-based glucose sensor exhibits good long-term stability, and excellent anti-interference ability to uric acid and ascorbic acid. The results can also be used for the performance optimization and the process standardization of other ZnONT-based amperometric biosensors.     

A unified approach to the real-time implementation ofmicroprocessor-based PWM waveforms

A method for real-time implementation of any two-level three-phase pulse-width-modulator (PWM) invertor waveform is discussed. The hardware and software of the scheme are built around the 16 b 8086 microprocessor and its peripherals, with a few additional digital ICs. The suggested scheme realizes the PWM waveforms without harmonic distortion. The implementation procedure is a universal one and it generates in real time any two-level three-phase PWM waveform with the chosen hardware structure. There is no need for hardware alteration for realization of different types of PWM waveforms     

环境辐射对实时测温仪测温精度的影响及抑制

在简要介绍一种利用半导体发光器件作辅助测量光源、以InGaAs光电二极管作光电转换器件实现的实时测温仪(工作波长1.5μm、波长带宽20nm、测温范围400℃至1100℃)的基础上,着重讨论了环境辐射体的辐射对其测温精度的影响,提出了抑制环境辐射体的辐射对仪器测温精度影响的三条措施:一是采用遮蔽板和孔径光阑;二是尽可能地使探测器正对待测面;三是进行电气补偿。进行了一些必要的分析与讨论,得到了采用遮蔽板和孔径光阑、尽可能地使探测器正对待测面和进行电气补偿可有效抑制环境辐射体的辐射对仪器测温精度的影响的结论。实验表明,采取这些措施后在仪器的测温范围内,其测温精度不低于0.2%、符合设计要求。