针对一台车用天然气发动机排气能量的变化规律,建立了带回热器有机朗肯循环系统,对比分析了采用纯工质R245fa和非共沸混合工质R416A时,带回热器有机朗肯循环系统的净输出功率、热效率、效率和单位工质能量输出密度。结果表明,采用非共沸混合工质R416A时上述各项性能指标均优于采用纯工质R245fa。最后,构建了天然气发动机-带回热器有机朗肯循环联合系统,采用非共沸混合工质R416A,分析了联合系统的热效率。结果表明,加装带回热器有机朗肯循环系统后,发动机热效率最大可提高7%。

关键词：天然气发动机；余热回收；有机朗肯循环；非共沸混合工质

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In the paper a robust Model Predictive Control structure for speed regulation of a drive system with an elastic transmission is proposed. A methodology for robust design based on suitable selection of the explicit form of MPC which enables the drive's safety and physical limitations to be directly incorporated into control synthesis is presented. The simulation results show that the controller is very effective in regulating load speed for a wide-range of the changes of the load side inertia. The simulation studies are confirmed through a variety of experimental tests.

关键词：鲁棒模型；预测；控制器

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Security is an important aspect of modern information management systems. The crucial role of security in this systems demands the use of tools and applications that are thoroughly validated and verified. However, the testing phase is an effort consuming activity that requires reliable supporting tools for speeding up this costly stage. Access control systems, based on the integration of new and existing tools are available in the Service Development Environment (SDE). We introduce an Access Control Testing toolchain (ACT) for designing and testing access control policies that includes the following features: (ⅰ) the graphical specification of an access control model and its translation into an XACML policy; (ⅱ) the derivation of test cases and their execution against the XACML policy; (ⅲ) the assessment of compliance between the XACML policy execution and the access control model. In addition, we illustrate the use of the ACT toolchain on a case study.

关键词：安全性；控制器；信息化管理系统

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为了有效控制柴油机NOx排放量,采用等体积浸渍法制备了一系列不同组合含量的钨基催化剂及掺杂不同过渡金属M的改性催化剂M-V2O5-WO3/TiO2(其中M可以是Ni,Zr,Fe,Cu),分别对两类催化剂进行了SCR脱硝活性测试,并进一步用XRD,TEM和NH3-TPD对催化剂进行了表征。研究表明,催化剂掺杂金属Zr时的催化效率较高,在低温(150℃)时也有较高的活性。催化剂活性增加的原因可能是掺杂金属Zr加强了V,W及载体TiO2的分散性,提高氧化还原能力和表面酸性,从而促进SCR性能。

关键词：氮氧化物；选择性催化还原；浸渍法；钒钨金属氧化物；催化剂

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为抑制不确定参数汽车制动器的制动噪声,基于区间分析理论,将响应面法与优化技术相结合,提出了一种降低系统复模态负阻尼比以提高汽车制动器稳定性的优化方法。该方法采用拉丁超立方试验设计在设计变量和不确定参数构成的混合空间内采样,建立了包含不确定参数的制动器系统复模态负阻尼比的响应面近似模型;以系统结构参数为设计变量,以最小化系统复模态负阻尼比为优化目标,利用基于区间分析的不确定性优化方法对响应面近似模型进行优化。对某型车的浮钳盘式制动器的优化结果表明,采用该方法对汽车制动器进行优化,能在整个使用周期内有效减小制动器不稳定模态的负阻尼比,从而提高制动器的稳定性。

关键词：制动噪声；不确定性；区间分析；优化

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In the present investigation novel needle-processed S2-glass laminates are fabricated and several key failure modes are characterized. Double cantilever beam testing shows that mode I fracture toughness improves up to 270% compared to non-needled baseline material. In-plane compressive strength of needled material improves by up to 475%. In plane tensile strength shows mixed results, improving by 6% for moderate volume fractions of through- thickness reinforcement (TTR) and decreasing by 6% at larger volume fractions. Double lap shear tests show that interlaminar shear strength improves as much as 17% for TTR inserted at 45 relative to the laminate plane. X-ray micro- computed tomography (micro-CT) is used to investigate the unique 3D microstructure resulting from the needling process for 90 TTR samples. The micro-CT reconstructions show that the dimensions of the disturbances of the inplane fabric are significantly smaller than those imparted by the conventional tufting or stitching processes at each penetration site. Micro-CT reveals that some penetration sites are aggregates of closely spaced neighbors, resulting from the lack of precise spatial control with the needling process used in the present research. At these aggregate locations the in-plane disturbances are roughly equal in size to those from tufting/stitching.

关键词：表征；复合材料；抗压强度；层间

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Stability of a fuzzy control system is closely related to the analytical structure of the fuzzy controller, which is determined by its components such as input and output fuzzy sets and fuzzy rules. We first characterize the mathematical input-output structure of fuzzy controllers and then utilize the structure characteristics to advance stability analysis. We study how the components of a general class of Mamdani fuzzy controllers dictate the controller's input-output relationship. The controllers can use input fuzzy sets of any types, arbitrary fuzzy rules, arbitrary inference methods, either Zadeh or the product fuzzy logic AND operator, singleton output fuzzy sets, and the centroid defuzzifier. We theoretically prove that regardless of the choices for the other components, if and only if Zadeh fuzzy AND operator and piecewise linear (e.g., trapezoidal or triangular) input fuzzy sets are used, the fuzzy controllers become a peculiar class of nonlinear controllers with the following interesting characteristics: (1) they are linear with respect to input variables; (2) their control gains dynamically change with the input variables; and (3) they become linear controllers with constant gains around the system equilibrium point. These properties make the fuzzy controllers suitable for analysis and design using conventional control theory. This necessary and sufficient condition becomes a sufficient condition if the product AND operator is employed instead. We name the fuzzy controllers of this peculiar class type-A fuzzy controllers. Taking advantage of this new structure knowledge, we have established a necessary and sufficient local stability condition for the type-A fuzzy control systems. It can be used not only for the stability determination, but also for practically designing a type-A fuzzy control system that is at least stable at the equilibrium point even when model of the controlled system is mathematically unknown. Three numerical examples are provided to demonstrate the utility of our new findings.

关键词：控制器；模糊控制系统；稳定性

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The integration of fuzzy systems, Wavelet theory, and neural networks has recently become a popular approach in the engineering fields for control of nonlinear systems. Therefore, the application of Fuzzy Wavelet Neural Network controllers is clearly obvious to investigators. A lot of research has been done in the control of nonlinear systems by using the models based on type-1 Fuzzy Logic Systems (FLS). However, they are regularly unable to handle uncertainties in the rules. This chapter develops a novel structure of Type-2 Fuzzy Wavelet Neural Networks (T2FWNN) to control a nonlinear system. This has been performed by invoking some of the specific advantages of wavelets, such as dynamic compatibility, compression, and step parameter adaptation along with a combination of type-2 fuzzy concepts regarding the neural networks abilities. The proposed network is constructed based on a set of TSK fuzzy rules that includes a wavelet function in the consequent part of each rule. This can provide appropriate tools on adaptation of plant output signal to follow a desired one. In this regard, the merits of utilizing wavelets and type-2 FLS simultaneously have been discussed and explored to efficiently handle the uncertainties. It is worth mentioning that the stability of the system is effectively dependent on the learning procedure and the initial values of the network parameters. Here, an adaptive gradient descent strategy is used to adjust the unknown parameters. Furthermore, the performance of the proposed T2FWNN is compared with the type-1 FLS networks. As investigated, this method has gained considerably high levels of accuracy with the reasonable number of parameters. Finally, the efficiency of the proposed approach is demonstrated via the simulation results of two nonlinear case studies.

关键词：模糊神经网络；非线性系统；控制

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In the last decade, the demand of micro products and miniaturization has seen a wide spread growth. Currently, micro products and micro features are produced through conventional macro scale ultra-precision machines and MEMS manufacturing techniques. These technologies have limitations as conventional machining centers consume large energy and space. For mass production of micro components using non-silicon materials and real 3D shapes or free-form surfaces, mechanical micro manufacturing technology based machine tools are developed as an alternative method. The principle of "Small equipment for small parts" is gaining trend towards the investigation on micro-machine tools. One example of miniaturization of manufacturing equipment and systems is the Japanese micro-factory concept. Few micro-machines and associated handling micro grippers and transfer arms are developed to create micro-factory. The manufacturing processes are performed in a desktop factory environment. To explore the micro-factory idea, large number of micro machines can be installed in a small work-floor. The control of this micro factory concept for operation, maintenance and monitoring becomes a Cyber-physical system capable of producing micro-precision products in a fully-automated manner at low cost. Manufacturing processing data and condition monitoring of micro machine tools in a micro factory are the variables of interest to run a smooth process flow. Every machine out of hundreds of micro machines will have sensing equipment and the sensors data is being compiled at one place, ideally using wireless communication systems. One or two operators can run and monitor the whole micro-factory and access the machine if the fault alarms receive from any station. A variety of sensors will be employed for machine control, process control, metrology and calibration, condition monitoring of machine tools, assembly and integration technology at the micro-scale resulting in smooth operation of micro-factory. Single machine can be designed with a computer numerical control, but, flexible reconfigurable controllers are envisioned to control variety of processes that will lead to the development of open architecture controllers to operate micro-factory. Therefore, the control effort and algorithms have to utilize process models to improve the overall process and, ultimately, the product. Thus, we aim to introduce machine to machine (M2M) communication in the micro factory test bed. M2M communication enables micro actuator/sensor & controller devices to communicate with each other directly i.e., without human intervention, automating management, monitoring, and data collection between devices, as well as communicating with neighboring machines. All micro sensors communicate with a local short distance wireless network e.g. via Bluetooth piconet as well as with a centralized controller via WLAN 802.11 to exchange control/command from it. In this chapter, inherent issues are first highlighted where bulk micro-part manufacturing is carried out using large size machines. State-of-the-art micro machine tool systems designed and developed so far are discussed. With the help of precision engineering fundamentals and miniaturization scaling issues, a design strategy is formulated for a high precision 3-axis CNC micro machine tool as a model for micro-factory working. Based on this, a mathematical model is built that includes machine's design variables and its inherent errors. The volumetric error between tool/work-piece is evaluated from the machine's mathematical model and further used as an objective function to be minimized. Robust design optimization at micro machine development stage reveals the sensitivity analysis of each design variable. The optimization analysis employs different design of Experiment (DOE) techniques to make initial population that is governed by multi-objective genetic algorithm. Hence, the robust design is achieved for 3-axis micro machine tool using the essential knowledge base. The technique is used to remove the machine's repeatable scale errors via calibration and is known as error mapping. These errors are entered into the machine controller, which has the capability of compensating for the error. The machine does not need any extra hardware. Error mapping is a cost-effective tool in achieving volumetric accuracy in a micro manufacturing system.

关键词：微工厂；微型计算机；机器人网络物理系统

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Approximately 89% of the paved-road network in Kansas is asphalt surfaced (bituminous and composite). According to the Kansas Department of Transportation (KDOT), typical design performance period of hot-mix asphalt (HMA) pavement for new construction or reconstruction is approximately 12 years. In most cases, these pavements are overlaid as they reach the end of their design life. Both bituminous and composite pavements are usually overlaid with Superpave HMA for pavement preservation. The new highway program of KDOT also emphasizes pavement preservation. KDOT is currently seeking to extend the lives of Superpave mixes for these overlays through educated better selection of asphalt and aggregates. Thus, KDOT is contemplating use of the Hamburg Wheel Tracking Device (HWTD) as a performance tester.

关键词：沥青；路面；试验设备；骨料；建筑

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