抽油杆减震器的碟形弹簧系统动力学仿真研究

弹性元件"增载压缩,卸载即恢复"的特性来储存能量和释放能量原理是防抽油杆疲劳断裂和脱扣的有效途径之一,但目前只有定性研究.定量研究抽油杆减震器中的蝶形弹簧组成的多体动力学系统,并建立了动力学方程.采用Fortran语言编程进行了动力学仿真,证明了抽油杆减震器可以有效地降低抽油杆作用于抽油机系统的附加动载荷,从而降低抽油机系统对抽油杆的位移激励,进而有效地避免抽油杆的脱扣和断裂.计算机仿真结果与现场试验结果相一致,定量研究为抽油杆减震器在工程中的应用提供了理论支持.     

虚拟原型多体动力学中设计模式仿真模型研究

通过分析机械系统多体动力学解算模型特点。从机械产品的协作开发与仿真角度。研究了基于组件方法建立机械系统虚拟原型,提出利用MVC设计模式构建多体动力学解算仿真模型。这种解算模式,实现了多体动力学解算仿真中。模型与解算逻辑的分离,维护了系统仿真中构件、铰约束、力元等组件的状态一致性。利于在不同的解算逻辑下组件和仿真方案的配置,方便了基于组件的协同开发与仿真。结果表明,基于组件的机械虚拟原型模型与多体动力学MVC仿真模型是可行的。     

铁道车辆减振器的数字设计

应用适用于现代车辆悬挂系统的设计与制造的液压减振器动态数学模型,有效描述研究模型参数与减振器的内部结构、零部件设置与减振器动态特性的关系. 将液压减振器动态数学模型作为用户模型加入MSC Adams,进行车辆系统动力学数值仿真研究. 以提速客车转向架CW 200为实例,应用液压减振器动态数学模型进行车辆悬挂系统参数的数值优化研究. 线路试验表明,应用新研制的减振器可明显改进车辆系统动力学性能.     

采用AMBA总线的SoC中UART的设计与实现

在“双向有线DTV信道传输SoC芯片”中,采用了AMBA总线作为片上总线,为了与外部设备进行串行通讯,必须设计采用AMBA总线接口的UART。介绍了UART的功能结构与实现方法。采用Top—Down的设计方法进行模块化设计,使用Verilog语言进行描述．最终用FPGA验证通过并投入使用。     

摩托车减震器动态复原阻尼特性测控系统设计

介绍了一种应用于摩托车减震器动态复原阻尼特性的检测新方法,及测控系统的功能、硬件组成、软件设计和测试结果分析.测控系统集传感器、数据采集和计算控制技术于一体,操作简单,实现了测试评价自动化,对产品质量提高具有重要意义,强化了减震器舒适性评价指标,是保证高端减震器性能和开发新型减震器的必要检测设备.     

Modelling of an hydraulic excavator using simplified refined instrumental variable (SRIV) algorithm

Instead of establishing mathematical hydraulic system models from physical laws usually done with the problems of complex modelling processes, low reliability and practicality caused by large uncertainties, a novel modelling method for a highly nonlinear system of a hydraulic excavator is presented. Based on the data collected in the excavator's arms driving experiments, a data-based excavator dynamic model using Simplified Refined Instrumental Variable (SRIV) identification and estimation algorithms is established. The validity of the proposed data-based model is indirectly demonstrated by the performance of computer simulation and the real machine motion control experiments.     

Modelling of an hydraulic excavator using simplified refined instrumental variable （SRIV） algorithm

Instead of establishing mathematical hydraulic system models from physical laws usually done with the problems of complex modelling processes, low reliability and practicality caused by large uncertainties, a novel modelling method for a highly nonlinear system of a hydraulic excavator is presented. Based on the data collected in the excavator＇s arms driving experiments, a data-based excavator dynamic model using Simplified Refined Instrumental Variable （SRIV） identification and estimation algorithms is established. The validity of the proposed data-based model is indirectly demonstrated by the performance of computer simulation and the.real machine motion control exoeriments.     

船舶集成平台中嵌入式CAN/Ethernet网关的设计与实现

本文研究了CANBus和Ethernet在船舶集成平台管理系统中的应用,设计了嵌入式CAN/Ethernet网关,用来实现CANBus和Ethernet之间的数据交换和信息集成。     

Design of suspension and swing arm for improved shock resistance in the micro optical disk drives

One of the trends on information storage device is focused on the development of micro optical disk with optical flying head (OFH). The OFH in the small form factor ODD consists of optical slider, suspension, swing arm, and so on. In order for a slider with OFH to be successfully implemented in the system, the shock performance of the head-gimbal assembly should be guaranteed for mobile applications. We design development model of suspension and swing arm for improved shock resistance using topology optimization and shape optimization. The objective of the suspension design is to decrease the equivalent mass with increasing first torsional frequency. The objective of the swing arm design is mass reduction for reducing power consumption and fast access time. In this paper, we suggest a design method for the improvement of the dynamic performance of suspension and swing arm for the OFH considering shock characteristics.     

Existence and stability of limit cycles in control of anti-lock braking systems with two boundaries via perturbation theory

This paper presents a two-phase control logic for anti-lock braking systems (ABS). ABS are by now a standard component in every modern car, preventing the wheels from going into a lock situation where the wheels are fixed by the brake and the stopping distances are greatly prolonged. There are different approaches to such control logics. An ABS design proposed in recent literature controls the wheel's slip by creating stable limit cycles in the corresponding phase space. This design is modified via an analytical approach that is derived from perturbation theory. Simulation results document shorter braking distance compared to available tests in the literature.     

Design optimization of an enzymatic assay in an electrokinetically-driven microfluidic device

Microfluidic systems are increasingly popular for rapid and cheap determinations of enzyme assays and other biochemical analysis. In this study reduced order models (ROM) were developed for the optimization of enzymatic assays performed in a microchip. The model enzyme assay used was β-galactosidase (β-Gal) that catalyzes the conversion of Resorufin β-d-galactopyranoside (RBG) to a fluorescent product as previously reported by Hadd et al. (Anal Chem 69(17): 3407–3412, 1997). The assay was implemented in a microfluidic device as a continuous flow system controlled electrokinetically and with a fluorescence detection device. The results from ROM agreed well with both computational fluid dynamic (CFD) simulations and experimental values. While the CFD model allowed for assessment of local transport phenomena, the CPU time was significantly reduced by the ROM approach. The operational parameters of the assay were optimized using the validated ROM to significantly reduce the amount of reagents consumed and the total biochip assay time. After optimization the analysis time would be reduced from 20 to 5.25 min which would also resulted in 50% reduction in reagent consumption.     

Design sensitivities of fatigue performance and structural dynamic response in an automotive application

Direct accounting for durability rarely finds its way into multidisciplinary optimization. Though reduction of loads by some means can certainly have a beneficial influence on the fatigue performance of a structure, changes in load levels are not a direct measure of the influence of design changes on fatigue performance. In this paper, an assessment is made of an approach to the calculation of design sensitivities of a fatigue performance index namely, number of damaging cycles to failure. The approach makes use of analytical sensitivities of structural dynamic response, and a standard approach to the calculation of fatigue performance. The method is demonstrated using a simple nine degree-of-freedom structural model of an automobile in a conceptual representation of the industrial practice of road testing and road simulation. Results suggest that the estimates of changes in fatigue life are of sufficient quality for typical fatigue life evaluations, and open the door for the incorporation of a direct measure of fatigue performance in formal structural optimization. Received January 27, 2000 Communicated by J. Sobieski     

基于多体系统动力学和有限元法的联合仿真在车桥耦合振动研究中的应用*

为了实现车桥耦合振动精细化仿真研究,利用多体系统动力学软件SIMPACK建立完整的车辆空间模型,采用空间杆系和板壳混合单元有限元方法建立桥梁的动力分析模型;然后将车辆和桥梁两个子系统在轮轨接触面离散的信息点上进行数据交换,实现车桥耦合振动联合仿真分析。以高速铁路上的简支梁桥为研究对象,采用基于多体系统动力学和有限元法结合的联合仿真技术,计算了弹性轮轨接触时动车组列车以不同车速通过桥梁的空间耦合振动响应,证明了该研究方法的可行性。     

粒子模拟中一种非结构化通用并行通信模式的研究和范型实现

中国科学院过程工程研究所多相反应实验室,建立了一个通用粒子模拟平台并已开始应用。目前类似的并行模拟系统采用的Shift并行通信模式往往有一些问题,需要一种新的通信模式来弥补它的不足。本文设计具有良好通用性的非结构化通信模式All2All,用来完成通用粒子方法模拟平台中计算节点问的通信。本文的算例证明这种通信模式可解决在粒子并行模拟Shift通信模式所不能处理的,具有复杂拓扑关系的相邻节点间的数据通信问题。本文设计的All2All通信模式方法只需稍加修改,就可以方便地应用于其它领域的并行计算系统。     

逆向工程中基于BP网络的自动特征识别器的设计与实现

应用BP网络技术设计了一种具有良好扩展性的基于前向反馈网络的自动特征识别器．该特征识别器能依据从三角网格模型中提取的输入信号自动识别出机械零件中常见的凸块、圆台、型腔、圆孔、台阶、直槽、T型槽、燕尾槽、V型槽等几何特征,并具有响应速度快、适应性广等优点．     

Design of fractional order modeling based extended non-minimal state space MPC for temperature in an industrial electric heating furnace

In this paper, an improved approach of extended non-minimal state space (ENMSS) fractional order model predictive control (FMPC) is presented and tested on the temperature model of an industrial heating furnace. In the fractional order model predictive control algorithm, fractional order single-input single-output (SISO) system is discretized via fractional order Grünwald-Letnikov (GL) definition. The ENMSS fractional order model that contains the state variable and the fractional order output tracking error is formulated by choosing appropriate state variables. Meanwhile, the fractional order integral is introduced into the cost function and the GL definition is used to obtain the discrete form of the continuous cost function. Then the control signals are derived by minimizing the fractional order cost function. Lastly, the temperature process control of a heating furnace is illustrated to reflect the performance of the proposed FMPC method. Simulation results show the effectiveness of the proposed FMPC method.     

Advancements in the design and validation of an air pollution integrated assessment model for Spain

This paper describes the design and application of the Atmospheric Evaluation and Research Integrated model for Spain (AERIS). Currently, AERIS can provide concentration profiles of NO₂, O₃, SO₂, NH₃, PM, as a response to emission variations of relevant sectors in Spain. Results are calculated using transfer matrices based on an air quality modelling system (AQMS) composed by the WRF (meteorology), SMOKE (emissions) and CMAQ (atmospheric-chemical processes) models. The AERIS outputs were statistically tested against the conventional AQMS and observations, revealing a good agreement in both cases. At the moment, integrated assessment in AERIS focuses only on the link between emissions and concentrations. The quantification of deposition, impacts (health, ecosystems) and costs will be introduced in the future. In conclusion, the main asset of AERIS is its accuracy in predicting air quality outcomes for different scenarios through a simple yet robust modelling framework, avoiding complex programming and long computing times.