Unified multi-domain modelling and simulation of space robot for capturing a moving target

Space robotic systems are expected to play an increasingly important role in the future on-orbit service. The applications include repairing, refueling or de-orbiting of a satellite, or removal of the space debris. The dynamical performances of space robotic system result from the multi-physics interactions between mechanical, electrical, electronic, control, etc. In this paper, we developed a unified multi-domain modelling and simulation system. The system is composed of the following modules: the path planner, joint controllers, motor and its driver, gearing mechanism of the space manipulators, the Guidance, Navigation, and Control (GNC) system, the actuators of the base, and the orbital environment, orbital dynamic and the multi-body dynamic of the whole system, etc. Based on this system, the operation during different stages, including far range rendezvous, close range rendezvous (is usually divided into two sub-phases: closing and final approach) and target capturing can be studied from the view of multi-physics domains. The key algorithms, such as pose (position and attitude) measurement, GNC of the base, path planning and control of the space manipulator, and so on, can be validated using the system. As examples, the capturing processes of a moving target under free-floating and attitude-controlled modes are simulated and the simulation results are given.     

An approach for moving object recognition based on BPR and CI

A recognition and classification method of multiple moving objects in traffic based on the combination of the Biomimetic Pattern Recognition (BPR) and Choquet Integral (CI) is proposed. The recognition process consists of three stages. At the first stage, vehicles and pedestrians are detected in video images and the area, the shape and the velocity features are obtained by classical methods. At the second stage, BPR is used to classify the Zernike moments extracted at the first stage. At the last stage, CI is then adopted for multi-features fusion based on the output of BPR, and the area and the velocity features obtained at the first stage to improve the recognition accuracy. Experiment results show that this approach is efficient.     

A tree-based particle swarm optimization for multicast routing

QoS multicast routing is a non-linear combinatorial optimization problem. It tries to find a multicast routing tree with minimal cost that can satisfy constraints such as bandwidth, delay, and delay jitter. This problem is NP-complete. The solution to such problems is often to search first for paths from the source node to each destination node and then integrate these paths into a multicast tree. Such a method, however, is slow and complex. To overcome these shortcomings, we propose a new method for tree-based optimization. Our algorithm optimizes the multicast tree directly, unlike the conventional solutions to finding paths and integrating them to generate a multicast tree. Our algorithm also applies particle swarm optimization to the solution to control the optimization orientation of the tree shape. Simulation results show that our algorithm performs well in searching, converging speed and adaptability scale.     

Video analysis based on volumetric event detection

During the past decade, feature extraction and knowledge acquisition based on video analysis have been extensively researched and tested on many applications such as closed-circuit television(CCTV)data analysis, large-scale public event control, and other daily security monitoring and surveillance operations with various degrees of success. However, since the actual video process is a multi-phased one and encompasses extensive theories and techniques ranging from fundamental image processing, computational geometry and graphics, and machine vision, to advanced artificial intelligence, pattern analysis, and even cognitive science, there are still many important problems to resolve before it can be widely applied. Among them, video event identification and detection are two prominent ones. Comparing with the most popular frame-to-frame processing mode of most of today's approaches and systems, this project reorganizes video data as a 3D volume structure that provides the hybrid spatial and temporal information in a unified space. This paper reports an innovative technique to transform original video frames to 3D volume structures denoted by spatial and temporal features. It then highlights the volume array structure in a so-called "pre-suspicion" mechanism for a later process. The focus of this report is the development of an effective and efficient voxel-based segmentation technique suitable to the volumetric nature of video events and ready for deployment in 3D clustering operations. The paper is concluded with a performance evaluation of the devised technique and discussion on the future work for accelerating the pre-processing of the original video data.     

复杂系统故障预测与健康管理(PHM)技术研究

目前PHM技术存在应用范围小,适用技术开发少的问题,限制其在普通民用设备中的推广应用,为扩大PHM技术的应用范围,提高复杂系统的经济可承受性,在深入研究PHM技术的概念和内涵的基础上,针对复杂系统的具体特点,分析了PHM技术推广应用的重大意义和存在问题;通过归纳总结,得出PHM应用于复杂系统的方法和流程,从建模角度提出基于PHM的故障预测模型设计的基本思路,为复杂系统的开发研制和维修保障应用PHM技术提供理论基础和支持.     

基于主从多机通信的机器人控制系统开发

为了实现对机器人的实时控制,要求主控制器与各个感应机构和执行机构之间高效稳定的通信;对机器人控制系统的开发,需要设计一种满足实时性和高效性要求的多机通信系统;控制系统采用二级分布式结构,主控制器作为上位机,各传感器和电机内置的微处理器作为下位机;基于AVR单片机的主从多机通信方式,利用半双工的异步串行方式通信;这种数字化的通信方式具有高效,稳定的优点,可以大大简化控制程序的开发;实验证明,应用这种控制系统的小型机器人具有灵活性高、开发周期短且稳定性高的特点.     

模糊控制动态过程能耗分析与优化

为计算和降低模糊控制算法影响下系统动态过程能量消耗,提出了模糊控制系统动态过程的能耗计算公式和一种节能优化设计算法.能耗计算公式采用模糊控制器输出量作为积分对象、采用动态过程调节时间作为积分区间;模糊控制系统节能优化设计算法包括4步;首先,在规定的性能指标下根据系统响应曲线的一般形式拟合出目标曲线;再根据目标曲线计算此时模糊控制系统动态过程能耗;然后,根据上升时间、超调对能耗的影响,调整目标曲线减小系统能耗;最后,用相平面法调整模糊规则使实际响应曲线符合节能目标曲线,从而得到节能的模糊控制算法;在温度控制系统设计中使用该能耗计算公式和优化算法,系统动态过程实际能耗降低15%,验证了公式的正确性和优化算法的有效性.     

基于C8051F330的机动车速度监测及无线传输系统

为实现对高速公路机动车行驶速度的全程监测及预警,设计了一种以C8051F330为控制核心的机动车速度监测及无线传输系统;详细叙述了系统设计原理与软硬件的实现方法,系统利用C8051F330单片机控制传感器实时采集机动车行驶速度信号并进行处理,通过RFID标签和读写器无线传输车辆速度、身份信息以及前方路况限速信息,从而实现对高速公路机动车速度的实时监测和预警功能;实验调试表明系统反应速度快、运行可靠且成本低,具有良好的应用前景.     

基于WIA-PA的无线网络低功耗设计与实现

能量问题是工业无线网络设计的一个核心问题;WIA-PA节点通常是通过自身携带能量非常有限的电池供电,而它们工作的环境通常是非常复杂甚至于人类是不可及的,通过更换电池的方式补给能量几乎是不可能的,因此,如何合理高效的使用有限的能量,最大限度的延长WIA-PA网络的生命周期,成为了人们研究的热点;介绍了中国无线工业联盟新推出的具有自主知识产权的WIA-PA技术规范,并从硬件设计和软件设计两个方面来降低网络节点的能量消耗,在不影响整体网络性能的基础上延长WIA-PA网络寿命.     

可持续发展教学团队建设的思考

可持续性发展的教学团队具有合理的教学体制,可以整合教学资源,推进教学改革,因此,建设可持续性发展教学团队是提高本科教学质量的重要举措。结合目前教学团队的建设情况,提出建设可持续性发展教学团队的几条建设性意见。