Optimal design and applicability of electric power steering system for automotive platform

The ongoing need for better fuel economy and lower exhaust pollution of vehicles has increased the employment of electric power steering(EPS)in automotives.Optimal design of EPS for a product family reduces the development and fabrication costs significantly.In this paper,the TOPSIS method along with the NSGA-Ⅱis employed to find an optimum family of EPS for an automotive platform.A multi-objective optimization problem is defined considering road feel,steering portability,RMS of Ackerman error,and product family penalty function(PFPF)as the conflicting objective functions.The results for the single objective optimization problems and the ones for the multi-objective optimization problem,as well as two suggested trade-off design points are presented,compared and discussed.For the two suggested points,performance at one objective function is deteriorated by about 1%,while the commonality is increased by 20%–40%,which shows the effectiveness of the proposed method in first finding the non-dominated design points and then selecting the trade-off among the obtained points.The results indicate that the obtained trade-off points have superior performance within the product family with maximum number of common parts.

Optimal Design of Stewart Platform Safety Mechanism

A safety mechanism capable of moving at will within the range of its whole link lengths is designed based on the link space. Sixteen extreme poses are obtained in a Stewart platform. The singular points of the extreme poses are solved by using homotopy method as well as the judgment condition of singular points, and thereby the maximum link lengths are achieved. The rotation angles of joints and the distances between two neighboring links are analyzed in a calculation example in which that the mechanism moves among the extreme poses is assumed. Then an algorithm to test the safety mechanism is presented taking the constraint conditions into account. A safety mechanism having optimal properties of global movement is worked out by optimizing all structural parameters through minimizing the average condition number of extreme poses.

Concept Design,Modeling and Station-keeping Attitude Control of an Earth Observation Platform

The stratosphere airship provides a unique and promising platform for earth observation. Researches on the project design and control scheme for earth observation platforms are still rarely documented. Nonlinear dynamics, model uncertainties, and external disturbances contribute to the difficulty in maneuvering the stratosphere airship. A key technical challenge for the earth observation platform is station keeping, or the ability to remain fixed over a geo-location. This paper investigates the conceptual design, modeling and station-keeping attitude control of the near-space earth observation platform. A conceptual design of the earth observation platform is presented. The dynamics model of the platform is derived from the Newton-Euler formulation, and the station-keeping control system of the platform is formulated. The station-keeping attitude control approach for the platform is proposed. The multi-input multi-output nonlinear control system is decoupled into three single-input single-output linear subsystems via feedback linearization, the attitude controller design is carried out on the new linear systems using terminal sliding mode control, and the global stability of the closed-loop system is proven by using the Lyapunov theorem. The performance of the designed control system is simulated by using the variable step Runge-Kutta integrator. Simulation results show that the control system tracks the commanded attitude with an error of zero, which verify the effectiveness and robustness of the designed control system in the presence of parametric uncertainties. The near-space earth observation platform has several advantages over satellites, such as high resolution, fast to deploy, and convenient to retrieve, and the proposed control scheme provides an effective approach for station-keeping attitude control of the earth observation platform.

Optimum Design of Jacket Platforms Considering Structure-Pile-Soil Interaction

This paper proposes an optimum design model for the offshore jacket platform considering multidesign criteria, multi-design constraints and the structure-pile-soil interaction, and gives an optimum design procedure in which the proposed optimum design model is used together with structural analysis software SAP91 and optimum algorithm software OPB1. The Chengbei (#)11 offshore platform, which lies in the Shengli oilfield, is designed by use of the above optimum design model. The results show that the optimum design model is stable, and it depends on neither the optimization algorithm nor initial values of design variables. All values of the objective function converge to the same minimum value, and the speed of convergence is high, showing that the proposed optimum design model is reasonable.

Finite Element Method for Design of Reinforced Concrete Offshore Platforms

A design method of reinforced concrete (R. C.) offshore platforms with nonlinear finite element analysis is proposed. According to the method, a computer program is developed. In this program nonlinear constitutive relationships and strength criteria of concrete and steel bars are included, and the progressive cracking and crushing of the concrete are taken into account. Based on the stress distribution obtained by the nonlinear finite element analysis, the amount of reinforcement in the control sections can be computed and adjusted automatically by the program to satisfy the requirement of the design. The amount of reinforcement required in the control sections, which are obtained with the nonlinear finite element analysis, is agreeable to that obtained in the experiment. This shows that the design method of R. C. offshore platform with the nonlinear finite element method proposed by the authors is reliable for practical use.

Investigation of Allowable Stresses for Fatigue Design of Fixed Offshore Platforms

Fatigue design method is usually used for estimating whether a platform structure meets the requirements of fatigue resistance. It is described in API RP-2A and ZC rules for fixed offshore platforms, in which the allowable stresses for fatigue design are defined. In this paper discussed are the allowable stresses related factors, such as wave climate, structural response, fatigue behaviour of structural members.

Design and Development of System Platform of "Study on Relationship between Natural Phenology and Climate Change" Based on WEB and GIS

[Objective] The research aimed to study design and development of system platform of 'study on relationship between natural phenology and climate change' based on WEB and GIS. [Method] Relied on the technologies of WEB and GIS, a set of system platform of 'study on relationship between natural phenology and climate change' was developed based on the hybrid architecture of C/S (Client/Server) and B/S (Browser/Server). Moreover, its establishing process and functional module were detailedly introduced. [Result] The natural phenology and climate change in Guangxi were research objects of system platform of 'study on relationship between natural phenology and climate change'. By combining WEB and GIS with database, the primary application of 'study on relationship between natural phenology and climate change' was realized. The system used hybrid architecture of C/S and B/S. The four-layer architectures were independent to improve security, stability and maintainability of system. The visual interface on the foreground was simply, clear and easy to use. The generating program of GIS three-dimensional graph on the background was real-time and high-efficiency, providing powerful guarantee for stable and safe operation of phenology research work process. The system had functions of inquiry, analysis, statistical diagram, GIS three-dimensional graph and data export. Through the analysis of natural phenology observation data, the system could find variation rule of natural phenology as three-dimensional space (longitude, latitude and altitude) and its relationship with climate change. [Conclusion] The research laid good foundation for further deeply carrying out application of 'study on relationship between natural phenology and climate change', and also provided reference basis for recognizing nature and using change rule of phenology to execute production scheduling and strategic decision (seed-introduction and regionalization).

A preliminary study on seismic design criteria of offshore platforms in Bohai Sea of China

This paper analyzes the seismicity in Bohai Sea,introducing a shape factor K to characterize the seismic risk distribution in sub-regions of the sea. Based on the seismic design ground motions for 46 platforms located in the Bohai Sea,a statistical analysis was performed for different peak ground acceleration (PGA) ratios at two different probability levels. In accordance with the two-stage design method,a scheme of two seismic design levels is proposed,and two seismic design objectives are established respectively for the strength level earthquake and the ductility level earthquake. By analogy with and comparison to the Chinese seismic design code for buildings,it is proposed that the probability level for the strength level earthquake and ductility level earthquake have a return period of 200 and 1000 - 2500 years,respectively. The validity of these proposed values is discussed. Finally,the PGAs corresponding to these two probability levels are calculated for different sub-regions of the Bohai Sea.

An Agent-Based Multimedia Intelligent Platform for Collaborative Design

Collaborative design can create added value in the design and production process by bringing the benefit of team work and cooperation in a concurrent and coordinated manner. However, distributed design knowledge and product data make the design process cumbersome. To facilitate collaborative design, an agent-based intelligent CAD platform is implemented. Intelligent agents are applied to the collaborative design. Adopting the JADE platform as framework, an intelligent collaborative design software (Co-Cad platform for short) is designed. In this platform, every man, design software, management software, equipment and resource is regarded as a single agent, the legacy design can be abstracted to be interaction between agents. Multimedia technology is integrated into Co-Cad platform, communication and identity authentication among collaborative designers from different areas are more convenient. Finally, an instance of collaborative design using Co-Cad platform is presented.

Multilevel Optimal Design of Prestressed Lightweight Concrete-Steel Platform Structures

The concrete-steel platform structure is rather complicated because it involves such materials as concrete, reinforcing bars, steel, and so on. If the traditional dimension optimization method is employed, the optimal design of the platform will meet many handicaps, even it cannot be implemented at all. The multilevel optimal design approach is an efficient tool for the solution of large-scale engineering structures. In this paper, this approach is applied to the optimal design of a concrete-steel platform, which is formulated as a system level optimal design problem and a set of uncoupled substructure level optimal design problems. The process of optimization is a process of iteration between system level and substructure level until the objective function converges. An illustrative example indicates that this method is effective in the optimal design of concrete-steel platforms.

Design of A Bionic Spudcan and Analysis of Penetration and Extraction Performances for Jack-up Platform

The mechanisms of soil structure interaction have drawn much attention in the past years in the installation and operation of jack-up platform. A bionic spudcan produced by biomimetic of egg and snail shell is proposed, and the performance of the penetration and extraction are analyzed by numerical method. The geometric contour of egg and snail shell is measured, and its mathematical model is established respectively. According to the structure of existing spudcan of jack-up platform, three kinds of typical biomimetic spudcan are designed. Furthermore, numerical analysis models of biomimetic spudcan are established respectively to study the soil structure interaction mechanism in the process of penetration and extraction, and contrastive analysis of resistance characteristics are carried out. To conclude, the results show that the biomimetic spudcan facilitates the platform installation, and it is also beneficial to the improvement of the bearing capacity of spudcan.

Reliability-Based Full-Life Cycle Optimum Design of Offshore Jacket Platform

Based on the consideration of operation environment and structural property, an optimum design model of offshore jacket platform is developed in this paper, namely, the reliability-based full-life cycle optimum design model. In this model, the time-dependent reliability assessment method for structural members is established by combination of the decrease of sectional size and performance deterioration of material. The initial investment, maintenance cost and failure loss cost are assembled into the model. The total cost of the platform structure system in its full service period is chosen as the objective function, and the initial reliabilities of the layer elements partitioned in advance are taken as the design variables. Different models are obtained, depending on whether the system reliability constraint is considered or not. This optimum design model can result in the lowest full-life cost and the optimal initial layer reliability of an offshore jacket platform in the design of marine structures. The feasibility of this model is illustrated with an actual jacket platform in the Liaodong Gulf as an example.

Design of Simulation Competition Platform Based on Cognitive Behavior Modeling

Cognitive behavior modeling of agent is an important component of simulation system,and there are some difficulties in the simulation of course teaching.When students make simulation experiments about cognitive behavior modeling,such as algorithm design and model construction,there is no simulation competition platform that is controllable,flexible and scalable.To solve this problem,we propose a simulation competition platform based on cognitive behavior modeling,called TankSim,for undergraduate and graduate students.This platform aims to cultivate studenfs team collaboration and innovation capability,and improve their learning motivation.This paper elaborates the proposed platform from three aspects,including demand analysis,platform design,and content design.

Process-oriented knowledge-sharing platform for chemical engineering design projects

A process-oriented knowledge-sharing platform is studied to improve knowledge sharing and project management of chemical engineering design enterprises. First, problems and characteristics of knowledge sharing in multi-projects of chemical engineering design are analyzed. Then based on theories of project management, process management, and knowledge management, a process-oriented knowledge-sharing platform is proposed. The platform has three characteristics: knowledge is divided into professional knowledge and project management knowledge; knowledge sharing is integrated with the project process, which makes knowledge sharing a necessary part of the project process and ensures the quantity of knowledge shared; the platform provides quantitative measurements of incentive mechanisms for knowledge providers and users which ensures the quality of knowledge shared. This knowledge-sharing platform uses two knowledge management tools, a knowledge map and a knowledge base, to support the platform.

Optimum Design for Offshore Platform Structural Reliability

In this paper, the main problems concerning reliability design of offshore platform structure are described and the general steps for the use of Safety Coefficient Method are presented.

基于介质响应原理的变压器油纸绝缘测试实验平台设计

油纸绝缘作为电力变压器中的主绝缘设备,在工业生产和电力传输应用中尤为重要,为验证油纸绝缘的性能状态,该文研制了基于介质响应原理的现场可编程电力电子控制实验平台。平台以LabVIEW编程环境和三电极测试装置作为载体,采用状态机框架设计了回复电压谱与极化谱测量流程,并嵌入聚类云模型算法实现油纸绝缘状态精准分类。该实验平台可促进理论知识与实践经验相结合的教学模式革新,满足实验探索、科学研究等多层次需求。

触摸振动反馈模拟教学实验平台设计与实现

设计并实现基于国产GD32 MCU的触摸振动反馈模拟教学实验平台。该平台采用GD32 MCU通过RS232串口接收触摸屏的点击触摸动作,通过控制微型线性振动电机的运动对触摸后的手感效果进行模拟。同时,研究PWM频率、占空比、持续时间等不同控制参数对触觉反馈模拟效果的影响。教学实验平台具有知识点综合性好、小型化、实验效果易于体验,可以用于电工电子类课程的课堂演示实验、本科课程设计、学生创新实践等教学环节。

服务设计视角下校园服务平台设计研究--以“校帮帮”APP为例

随着信息技术的不断发展,移动智能设备与互联网服务已成为校园生活的重要组成部分。为达成更全面、高效的校园服务愿景,文章从服务设计视角出发,梳理现有校园服务平台的服务内容及发展现状,提出以用户模型图驱动个性化服务、用户旅程图挖掘服务痛点、服务蓝图优化服务流程的设计策略。从关注用户个性化需求、融合情感化服务设计、优化界面设计三个维度拓展校园服务平台的设计思路。以期在最大程度满足用户需求的同时,提供更简洁便利的综合性服务,为高校校园服务平台建设提供价值的参考。

海洋石油平台仪表气系统工艺流程优化

海洋石油平台上部组块和钻机模块分别单独使用空气压缩机制造仪表气已有多年经验。文章从降本增效理念出发,将上部组块和钻机模块的仪表气系统进行一体化工艺设计,详细阐述了仪表气一体化工艺设计原则和注意事项;通过引入高压氮气工艺流程,优化密封隔离性仪表气罐尺寸,解决了因密封隔离性仪表气罐尺寸较大而影响平台总体布置的难题。

大数据平台在市域治安风险防控中的设计与应用

通过对大数据技术在市域治安风险防控应用中的现状与不足进行剖析,深度挖掘市域治安风险源头和应对方法.探讨了适用于市域治安风险防范的大数据平台设计的要素基础与设计基础,对市域治安风险防控大数据平台进行结构设计、流程设计和功能设计,给出了矛盾纠纷风险防控、平安校园风险防控、重点关注人员时空轨迹分析等功能的实现方法,深度分析了由矛盾纠纷引起刑事案的内在因素(变量)及各因素的特征.为大数据在市域治安风险防控中的应用提供支撑.