It is well-recognized that a transfer system response delay that reduces the test stability inevitably exists in real-time dynamic hybrid testing （RTDHT）. This paper focuses on the delay-dependent stability and adde...It is well-recognized that a transfer system response delay that reduces the test stability inevitably exists in real-time dynamic hybrid testing （RTDHT）. This paper focuses on the delay-dependent stability and added damping of SDOF systems in RTDHT. The exponential delay term is transferred into a rational fraction by the Pad6 approximation, and the delay-dependent stability conditions and instability mechanism of SDOF RTDHT systems are investigated by the root locus technique. First, the stability conditions are discussed separately for the cases of stiffness, mass, and damping experimental substructure. The use of root locus plots shows that the added damping effect and instability mechanism for mass are different from those for stiffness. For the stiffness experimental substructure case, the instability results from the inherent mode because of an obvious negative damping effect of the delay. For the mass case, the delay introduces an equivalent positive damping into the inherent mode, and instability occurs at an added high frequency mode. Then, the compound stability condition is investigated for a general case and the results show that the mass ratio may have both upper and lower limits to remain stable. Finally, a high-emulational virtual shaking table model is built to validate the stability conclusions.展开更多
The need for efficient and reproducible development processes for sensor and perception systems is growing with their increased use in modern vehicles. Such processes can be achieved by using virtual test environments...The need for efficient and reproducible development processes for sensor and perception systems is growing with their increased use in modern vehicles. Such processes can be achieved by using virtual test environments and virtual sensor models. In the context of this, the present paper documents the development of a sensor model for depth estimation of virtual three-dimensional scenarios. For this purpose, the geometric and algorithmic principles of stereoscopic camera systems are recreated in a virtual form. The model is implemented as a subroutine in the Epic Games Unreal Engine, which is one of the most common Game Engines. Its architecture consists of several independent procedures that enable a local depth estimation, but also a reconstruction of a whole three-dimensional scenery. In addition, a separate programme for calibrating the model is presented. In addition to the basic principles, the architecture and the implementation, this work also documents the evaluation of the model created. It is shown that the model meets specifically defined requirements for real-time capability and the accuracy of the evaluation. Thus, it is suitable for the virtual testing of common algorithms and highly automated driving functions.展开更多
为解决传统座舱试验台结构同质化及模块化设计不足等问题,采用亲和图法整理了汽车故障及用户初始需求;采用模糊Kano模型进行需求指标权重计算,并结合质量特性要素进行用户核心需求汇总;通过功能分析系统技术(Function Analysis System T...为解决传统座舱试验台结构同质化及模块化设计不足等问题,采用亲和图法整理了汽车故障及用户初始需求;采用模糊Kano模型进行需求指标权重计算,并结合质量特性要素进行用户核心需求汇总;通过功能分析系统技术(Function Analysis System Technique,FAST)黑箱模型将用户需求转化为功能需求,并引入公理设计(Axiomatic Design,AD)理论与功能-行为-结构(Function-Behavior-Structure,FBS)模型进行逐级映射,最终确定智能座舱柔性试验台的结构设计要素。该设计过程以用户核心需求为导向,通过FAST-AD-FBS集成方法的应用,克服了传统产品概念设计中用户需求与产品功能结构设计间存在矛盾的问题,为提高产品创新设计的完整性及准确性提供了理论参考。展开更多
基金State Key Laboratory of Hydroscience and Engineering Under Grant No.2008-TC-2National Natural Science Foundation of China Under Grant No.90510018,50779021 and 90715041
文摘It is well-recognized that a transfer system response delay that reduces the test stability inevitably exists in real-time dynamic hybrid testing （RTDHT）. This paper focuses on the delay-dependent stability and added damping of SDOF systems in RTDHT. The exponential delay term is transferred into a rational fraction by the Pad6 approximation, and the delay-dependent stability conditions and instability mechanism of SDOF RTDHT systems are investigated by the root locus technique. First, the stability conditions are discussed separately for the cases of stiffness, mass, and damping experimental substructure. The use of root locus plots shows that the added damping effect and instability mechanism for mass are different from those for stiffness. For the stiffness experimental substructure case, the instability results from the inherent mode because of an obvious negative damping effect of the delay. For the mass case, the delay introduces an equivalent positive damping into the inherent mode, and instability occurs at an added high frequency mode. Then, the compound stability condition is investigated for a general case and the results show that the mass ratio may have both upper and lower limits to remain stable. Finally, a high-emulational virtual shaking table model is built to validate the stability conclusions.
文摘The need for efficient and reproducible development processes for sensor and perception systems is growing with their increased use in modern vehicles. Such processes can be achieved by using virtual test environments and virtual sensor models. In the context of this, the present paper documents the development of a sensor model for depth estimation of virtual three-dimensional scenarios. For this purpose, the geometric and algorithmic principles of stereoscopic camera systems are recreated in a virtual form. The model is implemented as a subroutine in the Epic Games Unreal Engine, which is one of the most common Game Engines. Its architecture consists of several independent procedures that enable a local depth estimation, but also a reconstruction of a whole three-dimensional scenery. In addition, a separate programme for calibrating the model is presented. In addition to the basic principles, the architecture and the implementation, this work also documents the evaluation of the model created. It is shown that the model meets specifically defined requirements for real-time capability and the accuracy of the evaluation. Thus, it is suitable for the virtual testing of common algorithms and highly automated driving functions.
文摘为解决传统座舱试验台结构同质化及模块化设计不足等问题,采用亲和图法整理了汽车故障及用户初始需求;采用模糊Kano模型进行需求指标权重计算,并结合质量特性要素进行用户核心需求汇总;通过功能分析系统技术(Function Analysis System Technique,FAST)黑箱模型将用户需求转化为功能需求,并引入公理设计(Axiomatic Design,AD)理论与功能-行为-结构(Function-Behavior-Structure,FBS)模型进行逐级映射,最终确定智能座舱柔性试验台的结构设计要素。该设计过程以用户核心需求为导向,通过FAST-AD-FBS集成方法的应用,克服了传统产品概念设计中用户需求与产品功能结构设计间存在矛盾的问题,为提高产品创新设计的完整性及准确性提供了理论参考。
文摘为研究弓网离线电弧对机场广播式自动相关监视(automatic dependent surveillance broadcast,ADS-B)地面站系统的影响同时给出电分相对ADS-B地面站系统的保护距离,实测并分析了动车组弓网离线电弧典型辐射特性。测试结果表明,弓网离线电弧电磁发射,电分相处强度最大。距离电分相拉弧点23.3 m处实测数据结果为峰值检波的最大场强值达66 d BμV/m;准峰值检波较峰值检波降低约20 d B;平均值检波较准峰值又降低约14 d B。依据GB 6364(航空无线电导航台(站)电磁环境要求)的一般保护率条件,分析各种影响因素,给出电分相拉弧点距离ADS-B地面站系统的保护距离为537 m。本研究结果能够对动车邻近机场区域的线路设计与布局提供依据;同时也对国标的修订提供重要参考。
