刮刀及撕裂刀磨损实时监测系统

为降低人工检修的风险,提高施工效率,辅助盾构操作司机判断是否需要更换刀具,对刮刀磨损量的可视化管理系统进行研发。通过对电阻排式的磨损传感器进行研究,介绍传感器如何很好地将信号传至接收仪器并在上位机实时显示,并对刮刀及撕裂刀磨损实时监测系统进行详细阐述。将此套系统应用于北京新机场线地铁项目,结果表明： 磨损传感器精确度较高,通用性较强,磨损量可实时在上位机界面上显示,提高了盾构施工的效率。     

基于kinect的隧道三维重建技术及其应用研究

为解决传统地质素描技术在隧道中施作效率低、数据不连续且原始数据难以再现的问题,采用基于kinect传感器和kintinuous算法的隧道岩体三维重建方法,基于物理模型试验,确定三维重建过程中光源、TSDF立方体等主要参数指标,将模型试验重建误差控制在1.9%~2.5%,并将该参数指标应用于现场试验,重建出良好的隧道三维模型。结果表明,该方法在重建模型的全局鲁棒性和细节还原方面较好,具有可视化程度高、数据连续性强、操作简易等优点,有效改善了传统地质素描对裂缝、结构面等数据记录不够准确和不完善的问题。     

A Novel Practical Cooperative Diversity Method for the Power-Limited Wireless Sensor Network

A novel practical cooperative diversity method for power-limited wireless sensor network system was proposed. At first, the system model was presented and the cooperation problem is formulated under the minimum outage probability criterion, then the focus was put on the power efficiency of system, such as the relay selection, cooperation strategy and power allocation etc. At last the uniform procedure of the proposed method was given. The results of the simulation clearly demonstrate that our method not only has the properties of simple operation and wide applying scope, but also outperforms those of current classical methods on the aspect of outage probability under the basis of the same power limitation.     

A Distributed Virtual Backbone Formation for Wireless Ad Hoc and Sensor Networks

The virtual backbone is an approach for solving routing problems in wireless ad hoc and sensor networks. A connected dominating set (CDS) was proposed as a virtual backbone to improve the performance of wireless networks. The quality of a virtual backbone is measured not only by approximation factor, which is the ratio of its size to that of minimum CDS, but also time complexity and message complexity. In this paper, a distributed algorithm is presented to construct a minimum CDS for ad hoc and sensor networks. By destroying triangular loops in the virtual backbone, the proposed algorithm can effectively construct a CDS with smaller size. Moreover, our algorithm, which is fully localized, has a constant approximation ratio, linear message and time complexity, and low implementation complexity. The simulation results and theoretical analysis show that our algorithm has better efficiency and performance than conventional approaches.     

Optical fiber based slide tactile sensor for underwater robots

In the underwater environment, many visual sensors don’t work, and many sensors which work well for robots working in space or on land can not be used underwater. Therefore, an optical fiber slide tactile sensor was designed based on the inner modulation mechanism of optical fibers. The principles and structure of the sensor are explained in detail. Its static and dynamic characteristics were analyzed theoretically and then simulated. A dynamic characteristic model was built and the simulation made using the GA based neural network. In order to improve sensor response, the recognition model of the sensor was designed based on the ‘inverse solution’ principle of neural networks, increasing the control precision and the sensitivity of the manipulator.     

Development of a retrofit layer with an embedded array of piezoelectric sensors for transient pressure measurement in maritime applications

Measurement of transient pressure distribution on maritime structures is important for the assessment of the hydrodynamic loads applied. The commonly used pressure sensors are mostly bulky, need to be bolted to the structure, and/or only provide point-wise measurements. In this paper, an elastic matrix layer with a network of embedded piezoelectric sensors is proposed to address these issues. For experimental validation, a 400 × 400 × 5 mm epoxy layer is fabricated embedding 25 piezoelectric sensors on a square grid in accordance with Gauss-Lobatto-Legendre points. A finite element based inverse procedure is developed to reconstruct the pressure field from the electric potentials measured by the piezoelectric transducers. Feasibility of the concept is evaluated by measuring and reconstructing the pressure field generated by a travelling wave in a water tank. Sensitivity of the layer is also investigated through the experiments. The results indicate that the retrofit layer is capable of pressure field reconstruction, and that the presence of disturbances on the sensing surface does not affect the measurements in a notable way, while non-ideal conditions of the mounting can have a significant impact on the accuracy of the measurements. The results highlight the potential of the concept in pressure distribution measurements.     

基于物联网的无人水面艇航行状态监测系统设计

针对无人水面艇(Unmanned Surface Vessel, USV)航行状态监测及试航性能评估试验中的参数获取问题,设计一套USV航行状态监测系统。以物联网(Internet of Things, IoT)3层架构为基础,设计小尺寸、低功耗的监测方案。以多源传感器和STM32微控制器作为感知层,以远距离无线电(Long Range Radio, LoRa)网关及LoRa终端作为数据远程传输途径,以传输控制协议(TCP)作为数据远程传输协议,以云平台作为系统应用层,实现数据采集、传输和应用功能。基于监测系统要求,在应用层设置阈值实现航行状态预警功能。对系统功能及性能进行测试,结果表明,系统横、纵摇精度为±0.02°RMS,风速为(0.2±0.03) m/s,风向为±2.5°,所有监测参数技术指标均符合要求,且丢包率在通信距离小于1.4 km时为1.5%,较传统方法降低约22%。该系统可为进一步完善USV航行状态监测提供技术支持。