Positioning control of an underwater robot with tilting thrusters via decomposition of thrust vector

Positioning control of an underwater robot is a challenging problem due to the high disturbances of ocean flow. To overcome the high disturbance, a new underwater robot with tilting thrusters was proposed previously, which can compensate for disturbance by focusing the thrusting force in the direction of the disturbance. However, the tilting motion of the thrusters makes the system nonlinear, and the limited tilting speed sometimes makes the robot unstable. Therefore, an optimized controller is necessary. A new positioning controller is proposed for this robot using a vector decomposition method. Based on the dynamic model, the nonlinear force input term of the tilting thrusters is decomposed in the horizontal and vertical directions. Based on the decomposition, the solution is determined by a pseudo-inverse and null-space solution. Using the characteristics of the decomposed input matrix, the final solution can be found by solving a simple second-order algebraic equation to overcome the limitations of the tilting speed. The positioning was simulated to validate the proposed controller by comparing the results with a switching-based controller. Tracking results are also presented. In future work, a high-level control strategy will be developed to take advantage of the tilting thrusters by focusing the forcing direction toward the disturbance with a limited stability margin.

     

基于USB的卫星通用化地面测试软件的设计

针对当前卫星地面测试设备研制任务剧增、研制需求周期短、密度大、技术更新快的问题,将软件工程中的组件技术引入卫星测试软件领域,提出利用测试功能组件构建通用化测试软件的设计思路;首先,对现有卫星型号的地面测试任务做共性研究;然后,分析研究现有卫星数传分系统和测控分系统单机地面测试涵盖的所有测试功能,描述通用化测试软件的研制需求;以通用化和模块化的设计思路进行软件概要设计;通过分析软件组成、设计流程图、搭建软件界面等步骤进行软件详细设计;最后,软件实现;提出的基于USB接口的卫星通用化地面测试软件,通过某型号功放级地面测试和某型号Ka应答机地面测试,经验证,通用性强,覆盖功能全面,能较好地满足多个分系统单机设备的测试要求。     

基于安卓平台的电力作业信息系统的设计

文章实现了电力作业信息系统的设计,包括电力作业软件的设计以及Webservice服务器的组成结构。文章着重描述了电力作业手机软件GUI的设计、电子地图开发、数据库的设计方法;详细介绍了服务器端WebService的搭建及服务发布流程、服务器接口的设计。系统服务器采用Linux、Oracle数据库及Axis2＋Tomcat搭建WebService平台,采用第三方类库提供轻量级SOAP客户端的Ksoap2实现服务器与Android客户端数据的交互。本系统已经在义乌电力局进行试用,系统性能稳定、兼容性好、具有良好的可扩展性和广泛的应用价值。     

面向汽车零部件产业链云服务平台的采购订单整合技术

针对汽车零部件产业链供应商企业群的订单整合集成问题,提出了面向云服务平台订单整合的技术方案.在抽象出订单整合多级映射关系的基础上,建立了多层级订单映射树模型.采用弹性化的动态可配置接口,构建出面向汽车零部件产业链云服务平台的映射规则库,将复杂映射转换为直接映射.运用订单映射树的层级关系,采用映射整合算法,将来自不同整车厂的大批量异构订单整合为供应商企业群所需的零部件生产计划集.结果表明,运用多层级订单映射树模型能支撑面向汽车零部件产业链云服务平台订单整合的扩展应用.     

基于Google Earth的数字城市快速建模——以扬州科技学院扬子津校区为例

以扬州科技学院扬子津校区为例, 以Google Earth为数据源, 以ArcGIS和天正软件为平台, 针对建筑施工图是否佚失, 分别从两条路径制定数字城市建模方案, 一是利用ArcGIS进行建筑物空间位置控制, 二是在空间控制的基础上或利用ArcGIS建模并在SketchUp软件中对模型进行细化处理, 或是直接将建筑施工图导入GIS平台中, 最终将两类数据在ArcGIS平台加以融合, 从而使三维数字城市建模变得快速, 高效, 极大降低了数字城市建设的成本, 同时还对该成果在城市规划、楼盘营销、数字导航领域中的应用进行了初步探讨.     

Experimental study on total dissolved gas supersaturation in water

More and more high dams have been constructed and operated in China. The total dissolved gas (TDG) supersaturation caused by dam discharge leads to gas bubble disease or even death of fish. Through a series of experiments, the conditions and requirements of supersaturated TDG generation were examined in this study. The results show that pressure (water depth), aeration, and bubble dissolution time are required for supersaturated TDG generation, and the air-water contact area and turbulence intensity are the...     

Safe driving in a green world: A review of driver performance benchmarks and technologies to support ‘smart’ driving

Road transport is a significant source of both safety and environmental concerns. With climate change and fuel prices increasingly prominent on social and political agendas, many drivers are turning their thoughts to fuel efficient or ‘green’ (i.e., environmentally friendly) driving practices. Many vehicle manufacturers are satisfying this demand by offering green driving feedback or advice tools. However, there is a legitimate concern regarding the effects of such devices on road safety – both from the point of view of change in driving styles, as well as potential distraction caused by the in-vehicle feedback. In this paper, we appraise the benchmarks for safe and green driving, concluding that whilst they largely overlap, there are some specific circumstances in which the goals are in conflict. We go on to review current and emerging in-vehicle information systems which purport to affect safe and/or green driving, and discuss some fundamental ergonomics principles for the design of such devices. The results of the review are being used in the Foot-LITE project, aimed at developing a system to encourage ‘smart’ – that is safe and green – driving.     

Distraction 'on the buses': a novel framework of ergonomics methods for identifying sources and effects of bus driver distraction

Driver distraction represents a significant problem in the public transport sector. Various methods exist for investigating distraction; however, the majority are difficult to apply within the context of naturalistic bus driving. This article investigates the nature of bus driver distraction at a major Australian public transport company, including the sources of distraction present, and their effects on driver performance, through the application of a novel framework of ergonomics methods. The framework represents a novel approach for assessing distraction in a real world context. The findings suggest that there are a number of sources of distraction that could potentially distract bus drivers while driving, including those that derive from the driving task itself, and those that derive from the additional requirements associated with bus operation, such as passenger and ticketing-related distractions. A taxonomy of the sources of bus driver distraction identified is presented, along with a discussion of proposed countermeasures designed to remove the sources identified or mitigate their effects on driver performance.     

Approaches to extended non-quadratic stability and stabilization conditions for discrete-time Takagi–Sugeno fuzzy systems

This paper provides simple and effective linear matrix inequality (LMI) characterizations for the stability and stabilization conditions of discrete-time Takagi–Sugeno (T–S) fuzzy systems. To do this, more general classes of non-parallel distributed compensation (non-PDC) control laws and non-quadratic Lyapunov functions are presented. Unlike the conventional non-quadratic approaches using only current-time normalized fuzzy weighting functions, we consider not only the current-time fuzzy weighting functions but also the l-step-past (l?0) and one-step-ahead ones when constructing the control laws and Lyapunov functions. Consequently, by introducing additional decision variables, it can be shown that the proposed conditions include the existing ones found in the literature as particular cases. Examples are given to demonstrate the effectiveness of the approaches.     

Development of panel generation system for seakeeping analysis

In this paper, a panel generation system for analyzing seakeeping performance of a ship is developed. Given a set of offset data representing the ship hull, the system first creates a surface model of the ship. From the surface model, the wetted part of the ship is obtained by computing the intersection between the water surface and the hull, which is then processed to generate quadrilateral panels for the hull and the water surface. The system is designed to handle various kinds of ships such as ships with a mono-skeg, a twin-skeg and/or a bulbous bow in either an automatic or an interactive manner. Moreover, it can generate input panels for three different seakeeping analysis methods. Examples are provided to demonstrate the capabilities of the system.