A mechatronic sensing system for vehicle guidance and control

Magnetic sensing is used for control and guidance in intelligent transportation systems (ITS). This includes vehicle applications such as lane-keeping in intelligent cruise control as well as driver assistance in highway maintenance functions such as snow removal. This paper presents a new mechatronic magnetic sensing system for ITS. The new system has several advantages both in terms of its hardware design and its underlying reference detection algorithms, providing a significant improvement in performance, maintainability, and upgradability over existing systems. It is a mechatronic system in that it combines mechanical position sensing with electronics implementation of the hardware and the underlying algorithms.     

A two-frequency radar for vehicle automatic lateral control

The use of a side-looking radar in conjunction with a sidewall reflector is one means of obtaining lateral position information for use in vehicle automatic lateral control. The principle of operation of a two-frequency radar for such use is presented along with a discussion of the reflector design and construction difficulties. Some results of the full-scale testing of this radar using two different types of reflecting surfaces are included. The performance of this radar system is compared with that of the highly accurate wire follower. In general, tracking errors on the order of twice those obtained with the wire follower were achieved. It appears that with some redesign of the radar, performance equal to or better than that of the wire follower should eventually result.     

A silicon-thermopile-based infrared sensing array for use in automated manufacturing

This paper describes a new low-cost infrared detector array that has been realized using standard silicon MOS process technology and micromachining. This array uses thermopiles as infrared detecting elements and multiple layers of silicon oxide and silicon nitride for diaphragm windows measuring 0.4 mm × 0.7 mm × 1.3 µm. Each thermopile consists of 40 polysilicon-gold thermocouples. A high fill factor for this array structure has been achieved by using the boron etch-stop technique to provide 20-µm thick silicon support rims. The array shows a response time of less than 10 ms, a responsivity of 12 V/ W; and a broad-band input spectral sensitivity. The process is compatible with silicon MOS devices, and a 16 × 2 staggered array with on-chip multiplexers has been designed for applications in process monitoring. The array theoretically achieves an NETD of 0.9°C and an MRTD of 1.4°C at a spatial frequency of 0.2 Hz/mrad in a typical imaging system.     

A new active position sensing method for ropeless elevator

Traditional cable driven elevators perform poorly in high-rise buildings because the weight of the cable limits the payload, and its elasticity degrades control performance. Further, it is not mechanically possible to include several elevator cars in the same hoistway because of the cable. However such multi-car elevator systems are desirable since they reduce passenger waiting time and reduce the space requirements of the elevator system. A promising solution is to use long armature linear motors spanning the hoistway to directly drive elevator cages. In such applications, the mover position sensing method must be explicitly addressed since most active position sensing methods require traveling cables, which are also an obstacle for multi-car elevator systems.In this paper, the linear-motor active position sensing method is formally introduced and the principle of operation, design and real-time operation methods are presented. The proposed method is used to measure the position of the mover of a long armature permanent magnet linear synchronous motor requiring no active components on the mover, thus traveling cables are eliminated. The principle of operation is inspired by linear variable differential transformer: A magnetic shunt positioned at a fixed distance ahead of the mover deforms the magnetic field created by one of the armature coils. The deformation can be determined by measuring the induced voltages on the neighboring coils, and the position of the shunt, and thus the mover, can be calculated.A design method for the optimal dimensions of the shunt for a given armature to provide long measurement range and small maximum position error is presented, accompanied by a real-time measurement algorithm that will enable the motor to be driven using the method. Finally the method is verified by simulations and experimental results conducted on a full scale linear-motor elevator prototype that was constructed in the laboratory.     

基于北斗定位的智能公交车载系统的设计

介绍了一种新型智能公交车载系统,以Cortex-M3处理器STM32为硬件核心,运用北斗定位、GPRS和MP3语音播放等技术,实现了公交车智能语音报站、LCD液晶显示、实时定位和远程监控等功能。文章主要对智能公交车载系统的总体方案、硬件设计和软件实现进行了详细的介绍。     

A control system for automated multiscale measuring systems

Quality inspection of micro systems on wafer scale must cope with conflicting demands: nanometer accuracy and high velocity in a comparatively large workspace. An Automated Multiscale Measuring System (AMMS) combines multiple sensors that operate at specific scales by an intelligent measurement strategy in order to balance speed and accuracy. The AMMS demonstrator is based on a modified Mahr MFU 100 with a position and tilt deflection measurement resolution of 1 nm. In this paper multiscale models of a horizontal axis with an operating range of 200 mm and their application to state linearization and control parameterization of the residual dynamics according to multiscale sensor system characteristics are developed and discussed. Main modeling issues are sliding and submicron presliding friction for model-based compensation and control, reaching from submicron positioning to high-velocity trajectory tracking with desired performance. A new experimental design for the identification of presliding friction parameters and a higher-order friction calculator are presented. Experimental results show the effectiveness of this approach.     

A PC-based imaging system for automated platelet identification

In this communication, a PC-based imaging system was developed for automatically identifying fluorescence-labeled individual platelets adherent to protein-coated surface under flow conditions. It is to eliminate the laborious and time-consuming task, and the subjective error of manual measurements. Based upon the features of adherent platelets, three passes of the image processing were developed for platelet identification. From the results, 90-95% accuracy could be routinely obtained. The platelet distribution and other related parameters could be easily extracted and investigated.     

A novel sliding-mode observer for indirect position sensing ofswitched reluctance motor drives

A switched reluctance motor (SRM) drive generally requires a rotor position sensor for commutation and current control. However, the use of this position sensor increases both cost and size of the motor drive and causes limitations for industrial applications. In this paper, a novel indirect position sensing technique, namely, the sliding-mode observer, is proposed for SRM drives. The corresponding design approach and operating performance are provided to illustrate the fast convergence and high robustness of the observer against disturbances and variations     

An evolutionary approach to visual sensing for vehicle navigation

This paper presents an evolutionary approach able to process a digital image and detect tracks left by preceding vehicles on ice and snow in Antarctica. Biologically inspired by a colony of ants able to interact and cooperate to determine the shortest path to the food, this approach is based on autonomous agents moving along the image pixels and iteratively improving an initial coarse solution. The unfriendly Antarctic environment makes this image analysis problem extremely challenging, since light reflections, abruptly varying brightness conditions, and different terrain slopes must be considered as well. The ant-based approach is compared to a more traditional Hough-based solution and the results are discussed.     

Real-time sensing of tooth position for dental digital subtractionradiography

Dental digital subtraction radiography requires accurate repositioning of the patient and X-ray source in order to facilitate correct diagnostic of bone loss. Present mechanical repositioning systems do not allow radiography of posterior teeth, and are uncomfortable for the patient. A new repositioning system that utilizes a six degrees of freedom position sensor and a robot arm with X-ray source is proposed. A mathematical model for the system is given, and the robot arm solution is obtained based on patient position. An error analysis is performed in order to determine the influence of sensor and robot errors on system accuracy. A series of experiments to determine sensor noise and accuracy are described. These tests showed relatively small errors over the work envelope of the sensor. Further tests showed that there is no adverse effect due to the presence of metal work in the patient's mouth. The high bandwidth of the sensor may allow real time tracking of small movements of the patient's head.     

Wire-reference configurations in vehicle lateral control

Lateral control is an essential function for all forms of individual automated ground transport. Here two aspects of such control--the magnetic field distributions associated with a guideway-based, wire-reference configuration, and the associated vehicle-based sensors--are reviewed. Two wire-reference schemes have thus far been suggested. In the first, the amplitude characteristics of the magnetic field are employed to obtain the lateral control signal. In this paper, a theoretical analysis and detailed field measurements are used to define both "ideal" characteristics and those which would be encountered in a realistic operating environment. The resulting problems, which involve amplitude distortions of the field due to the proximity of steel-reinforcing materials, are defined, and their effects on vehicle control--poor tracking and passenger discomfort--are discussed. In the second approach, the lateral control signal is primarily dependent on the phase characteristics of the magnetic field. A theoretical analysis and a corresponding experimental field study, which are discussed herein, indicated that the problems associated with the first approach were largely overcome, as evidenced by successful full-scale tests of an automatically steered vehicle.     

A statistical self-organizing learning system for remote sensing classification

A new learning system called a statistical self-organizing learning system (SSOLS), combining functional-link neural networks, statistical hypothesis testing, and self-organization of a number of enhancement nodes, is introduced for remote sensing applications. Its structure consists of two stages, a mapping stage and a learning stage. The input training vectors are initially mapped to the enhancement vectors in the mapping stage by multiplying with a random matrix, followed by pointwise nonlinear transformations. Starting with only one enhancement node, the enhancement layer incrementally adds an extra node in each iteration. The optimum dimension of the enhancement layer is determined by using an efficient leave-one-out cross-validation method. In this way, the number of enhancement nodes is also learned automatically. A t-test algorithm can also be applied to the mapping stage to mitigate the effect of overfitting and to further reduce the number of enhancement nodes required, resulting in a more compact network. In the learning stage, both the input vectors and the enhancement vectors are fed into a least squares learning module to obtain the estimated output vectors. This is made possible by choosing the output layer linear. In addition, several SSOLSs can be trained independently in parallel to form a consensual SSOLS, whose final output is a linear combination of the outputs of each SSOLS module. The SSOLS is simple, fast to compute, and suitable for remote sensing applications, especially with hyperspectral image data of high dimensionality.     

Road vehicle communication system for vehicle control using leakycoaxial cable

A new road vehicle communication (RVC) system that provides continuous communication between vehicles and control centers using a leaky coaxial cable is presented. The system operates in the quasi-microwave band providing high-quality communication through a well-designed communication protocol. An experimental setup and future directions are also included in this article     

A new position sensing X-ray detector: working principle andexperimental results

The working principle and the first experimental characterization of a new fully depleted X-ray detector, called controlled-drift detector (CDD), are presented. The detector is operated in integrate-readout mode. During the integration phase the signal electrons generated by the incident X-ray are stored in suitably engineered potential wells. During the readout phase the potential wells are removed and replaced by a uniform drift field that transports the signal electrons to the readout electrode. The drift time gives the position of incidence. Full depletion of the detector wafer allows for high X-ray efficiency and for backward illumination. The first experimental measurements demonstrate the fast readout of the integrated signal electrons achievable with a static drift field. At a drift field of 300 V/cm the measured readout speed is 0.35 cm/μs. The expected charge handling capacity is 10⁵-10⁶ electrons per pixel. The new detector provides unambiguous two-dimensional (2-D) position measurement with readout times of the order of 10 μs     

陆用车载组合导航系统里程仪快速标定

为减小里程仪刻度因子误差对组合导航精度的影响,分析了安装误差以及轮胎内外温度与里程仪刻度因子的关系,提出组合导航系统中里程仪快速标定法,推导出组合导航系统卡尔曼滤波方程,进行系统仿真。结果表明,将里程仪刻度系数进行标定后,里程仪刻度系数误差明显提高两个量级,里程仪测量输出数据的准确度也明显提高,同时组合导航的定位精度也得到了提高。     

Development of an automated steering vehicle based on roadwaymagnets-a case study of mechatronic system design

Automated steering control is a crucial element of vehicle automation. The California PATH Program at the University of California at Berkeley has developed one such system using magnetic markers embedded under the roadway for lateral guidance. This system was demonstrated during the August 1997 National Automated Highway System Consortium Feasibility Demonstration, San Diego, CA, without a single failure. Developing a successful demonstration system not only required theoretical understanding of the various control problems involved, but also strong appreciation of all practical issues. In the paper, the comprehensive process of developing such automated steering control system is described. This process consists of control objectives' determination, system structure definition, vehicle dynamics validation, lateral sensing system development, steering actuator design, test track installation, control algorithm development, software/hardware integration, and vehicle testing. The entire process also serves as a good case study for mechatronic system design integrating mechanical components, electronic devices, intelligence, and feedback control to perform vehicle automation functions     

声光滤波原理在光纤光栅中的应用

光纤光栅波长信号的解调是当前光纤传感领域中的关键技术之一,也是研究的热点。文中介绍了一种基于光纤光栅反射滤波技术,利用声光滤波器（AOTF）对反射谱进行动态扫描的波长解调方案,并给出了详细的理论推导和分析。本方案采用全光纤结构,数据经计算机处理,有效地提高了波长解调精度和系统稳定性。通过将波长的变化量转化为相对光强的变化,避免了使用光谱仪等昂贵设备,便于光纤光栅传感器的实际应用。     

FLASH: A disabled vehicle detection system

The flash lights and send help (FLASH) system uses an electro-optical detector designed to enable passing drivers to conveniently summon assistance for motorists in distress. The driver signals at designated reporting stations by flashing his high-beam lights three times. A roadside unit detects the headlight flashes and transmits an identifying tone signal to a central monitoring station, whose operator dispatches a service vehicle to the section of road under that detector's jurisdiction. The detector performs reliably over a range of 1000 feet during daylight or darkness, bridging an illumination ratio of up to 1:10 000 000 without a mechanical iris. The concept, design, and mechanical construction of the system is discussed in relation to the technical fulfillment of practical operational requirements. These include day and night operation, variations in temperature and weather conditions, random reflections, public safety, pranksters, vandalism, and repair and maintenance. A detector knockdown alarm, system test mode, and an audio alarm are incorporated on an illuminated road-status display panel located at the central monitoring station. A prototype system is presently being installed on a 50-mile (80-km) section of Interstate 4 between Tampa and Orlando in Florida, and will be operated by the Florida highway patrol during a 1-year evaluation period.     

一种车辆移动位置和姿态的精确测量方法

驾驶人场地驾驶技能考试需要实时检测考车在场地中的位置及其与场地标志、标线、测试物之间的距离,针对这一要求,本文基于RTK GPS定位技术,采用二点定位法,对考车的位置和姿态进行精确测量,进而求出考车车身上任意一点的位置,结合测绘得到的考场电子地图,求出考车车身与场地上任意一点的距离,实现场地驾驶技能考试的自动检测。本文给出该方法工作原理和具体应用。