圆锥滚子蜗形凸轮轮廓曲面的数学模型

蜗形凸轮是电子工业专用设备中的重要机构，它用来实现交错轴间的分度运动。本文应用齐次变换和微分几何的理论及方法建立了圆锥滚子蜗形凸轮轮廓曲面的数学模型。该模型运用矩阵算法，理论正确，计算精确，便于在计算机上计算。由于蜗形凸轮在使用中，滚子多为圆锥形，因比该模型有较强的实用性，是转位凸轮ＣＡＤ／ＣＡＭ系统的重要基础。     

某型号凸轮型线的参数选取及优化

以MFB2型凸轮为例,讲述了它的优点及参数的选取,然后应用matlab,再以某柴油机为例计算出多组进、排气升程曲线,最后应用GT-power仿真计算功能进行优化,并以外特性为优化目标,得出合适的凸轮型线参数,进而优化出合理的凸轮升程曲线。     

Ku波段宽带平行耦合微带线带通滤波器的设计

阐述了平行耦合微带线滤波器的原理,利用Matlab编程计算,结合ADS2009的原理图与Momentum进行联合优化仿真,同时给出了中心频率在16.1 GHz、宽带为1.6 GHz的滤波器设计实例与步骤。仿真结果显示,该设计满足工程需求,并计划投入生产。     

变焦凸轮曲线的优化设计方法

变焦凸轮是变焦镜头中驱动各个镜组运动的关键部件,凸轮曲线的设计结果决定了变焦系统的运动性能、系统精度以及系统成像等方面的特性,因此,变焦凸轮的设计是变焦距镜头设计中重要环节之一,优良的凸轮性能是实现镜头光学设计像质目标和连续变焦过程的基本要求。为了设计出优良的曲线形态以确保凸轮具有较小的压力角,使变焦过程平滑稳定、运动流畅,既能有效减小变焦系统的驱动力矩,又可以确保变焦成像的稳定性。在凸轮设计过程中,分别构造凸轮变倍组和补偿组驱动力矩与各自压力角的函数表达式,再以它们的函数组合构造整体目标优化函数,优化计算变倍曲线压力角与补偿曲线压力角的最优值,优化计算结果表明,优化后凸轮等效驱动力矩显著减小,能够有效改善变焦凸轮的整体性能。     

平行耦合微带线带通滤波器的研究与设计

由于其优越的性能,微带线形式的各种滤波器已成为广泛使用的射频器件.本文重点研究平行耦合微带线带通滤波器的原理和设计方法,并且对其不足之处,提出了全等宽平行耦舍微带线带通滤波器的设计思路.最后,结合具体应用实例,通过仿真计算,对两种形式的滤波器进行比较.结果表明全等宽平行耦合微带线带通滤波器适用带宽较宽,且结构简洁,大大降低了设计及仿真调试的复杂度.     

平面盘型凸轮机构CAD系统的开发及三维运动仿真

应用Visual C^ 6．0为开发工具并结合SolidWork三维实体造型软件，开发出了平面盘型凸轮机构设计CAD系统，实现了凸轮机构设计的自动化、三维实体造型与运动仿真。     

平行板波导CTS 天线的设计与分析

采用传输线理论的方法分析设计了平行板波导CTS 天线。建立平行板波导天线的等效电路模型,利用传输线方 程计算天线上的电压分布、电流分布以及辐射阻抗,进而分析远场的辐射特性。最后用Ansoft HFSS 软件仿真验证了该 方法的正确性。     

用于160×120元非制冷热像仪的红外连续变焦镜头

文中设计了一种用于非制冷焦平面热像仪的连续变焦镜头,并在此基础上编制了用于计算两组元连续变焦凸轮曲线的程序,该程序基于光学设计软件Code V的Macro语言,它可以直观描绘凸轮曲线的形状,为凸轮的设计与加工提供参考。     

双波段航空相机红外调焦机构的设计

为了补偿双波段航空相机在复杂环境下产生的离焦,设计了一套调焦机构。该调焦机构通过采用蜗轮蜗杆和 偏心凸轮的传动方式,将凸轮的旋转运动转化为调焦镜的直线运动,解决了离焦问题。该机构具有传动比大、运行平 稳,结构紧凑,抗振、抗冲击,可实现自锁以及模块化等优点。通过计算可知,该机构的调焦镜的位移 精度为0.0026mm,满足使用要求。仿真分析结果表明,该方法具有可行性。     

连续变焦光机系统凸轮轮廓设计

介绍了光学连续变焦物镜的工作原理以及光路计算过程。对绘图法设计凸轮轮廓产生误差的原因进行了简单分析。利用Pro/E设计软件,对凸轮零件轮廓进行了三维详细设计,准确还原了连续变焦光学系统中变倍组和补偿组透镜的运动规律,提高了凸轮轮廓的设计精度。     

一种连续变焦凸轮优化设计及试验验证

具备连续变焦功能是目前先进红外热像仪的重要特征之一,而变焦凸轮是驱动连续变焦光学系统中各镜组运动的关键部件。为了设计出良好性能的变焦凸轮结构,本文首先应用动态光学理论推导出变焦光学系统的像移补偿组公式得到像移补偿组的轨迹曲线,然后利用序列二次规划法（sequential quadratic programming, SQP）优化算法来减小动态光学曲线的压力角,结合光机设计理论运用Creo进行凸轮曲线生成及凸轮槽切除从而获得变焦凸轮结构。再基于有限元分析理论对凸轮结构进行分析,最终通过变焦系统运动及成像结果确认本文方法可行。     

凸轮轴自动检测仪的研制

介绍了凸轮轴检测仪的原理，硬件电路及软件的设计。该仪器采用计算机控制技术，能够按凸轮轴任意基准进行换算，可检测凸轮轴上齿轮的螺旋角，还具有分析对称或非对称凸轮总误差，相邻差、偏心差、凸轮夹角、圆柱度及凸轮斜度等功能。     

Condition assessment for automatic tool changer based on sparsity-enabled signal decomposition method

Automatic tool changer (ATC) is one of the key basic parts in CNC machining centers, and the globoidal indexing cam and the groove cam are the functional units for tool changing. Thus the condition monitoring is important for highly efficient and precision machining. In this paper, a condition monitoring system is constructed for the ATC, especially for the globoidal indexing cam, including vibration signal acquisition, fault feature extraction and localization, and condition assessment. In the constructed system, sparsity-enabled signal decomposition method is introduced to extract transient component and reduce noises in the complex vibration signals, and the transient component is always a key feature for fault localization. Simulation study shows that the sparsity-enabled signal decomposition method is effective in transient feature extraction. The experimental application in condition assessment for the ATC demonstrates that the constructed condition monitoring system has the potential to assess the working condition of the ATC in practical application.     

一种高精度角度定位装置

高精度角度定位装置是基于多齿分度技术,通过控制电路对转位电机和升降电机的控制,实现多位置高精度角度定位。该文详细介绍了高精度角度定位装置的结构设计和实现途径。实验结果表明,该装置最大分度误差小且重复定位精度高,可广泛应用于多位置法陀螺寻北。     

Hybrid cam mechanisms

This paper investigates the problem of driving a machine with several reciprocating heavy inertias. The drive should also realize some programmable flexibility of the motion, so that the operation of the machine, e,g., synchronization between different motions and duration of standstills, can easily be modified. The use of a single servomotor for every motion is not the best solution, since it does not allow for energy recuperation. This means that the installed servomotor power will be much higher than the required net peak power for the machine as a whole. The presented solution, however, reduces the servomotor peak torque and power by one order of magnitude, and makes energy transfer between the motions possible. The hybrid cam mechanism consists of a hybrid drive, which is a combination of a servomotor, a constant velocity motor and a cam follower mechanism. The operation principle exploits the nonlinear characteristics of the cam to add flexibility at low cost of energy. The hybrid solution is particularly successful for motions involving high peak acceleration. In addition, the concept can be used to reject disturbances. Simulations show the performance of the hybrid cam mechanism.     

Data Organization and Retrieval on Parallel Air Channels: Performance and Energy Issues

Our interest in the global information sharing process is motivated by the advances in communication and computation technologies, the marriage between the two technologies, and the almost limitless amount of information available on the network. Within the scope of the global information sharing process, when a user's request (potentially mobile) is directed to public data, broadcasting has been suggested as an effective mechanism to access data. The effectiveness of the schemes to retrieve public data is determined by their ability to reduce the access latency and power consumed by the mobile unit. Various indexing techniques can be used to further improve the effectiveness of retrieving broadcast data.This paper addresses the application of object indexing in parallel broadcast channels. In addition, to further reduce access latency, it proposes several scheduling schemes to order accesses to the data objects on parallel channels. The proposed schemes are simulated, and analyzed. Our simulation results indicate that the employment of indexing scheme and proper scheduling of object retrieval along the parallel channels drastically reduces both the access latency and power consumption at the mobile unit.     

Energy optimization of a certain class of incremental motion DCdrives

A joint approach to the design and control of energy-optimal incremental motion, load-invariant DC drives is presented. The drive is to rotate a given load through a definite angle in limited time, at minimum energy dissipation in the motor windings. It is required that the motor be of the minimum possible rating. An energy-optimal multimode control strategy for the drive is developed, and its microprocessor-based implementation is proposed. The motor and the so-called key parameters of the drive are determined by graphical solution of a nonlinear constrained optimization problem. A design example is included to illustrate the theoretical considerations     

经纬仪调焦机构设计

调焦机构是变焦距镜头中重要的组成部分,为了满足经纬仪测量中对变焦距镜头的要求,针对目前对变焦距镜头的调焦主要采用凸轮机构的变焦方式体积大、效率低、精度差缺点,本文提出了采用直线驱动的方式进行调焦的原理与方法,介绍了一种应用系统,主要由步进电机、直线导轨、直线位移传感器、DSP控制器等组成,由步进电机驱动,通过齿轮变速和精密丝杠速比变换机构,利用直线位移传感器作为检测元件,带动镜组前后移动来进行距离调焦和温度调焦,从而改变了传统的调焦机械结构。具体给出了测量系统的组成结构和实验结果,并进行了精度影响因素分析。实验结果表明,测量精度可保证在0.005mm内,满足经纬仪测量所需要的结构紧凑、位移精度好的要求。     

THE Drive-Wave Shape Influence on the Class C Tuned HF High-Power Amplifiers

The paper investigates the drive-wave shape influence on the performances of tuned HF high-power amplifiers. Using the linear model of high-power HF triode and changing the drive wave shape (cosine, triangular, trapezoidal and pulse) under the same conditions (conducting angle, drive level), the balance of power for the high efficiency design, representing the normalized maximum output power and the efficiency versus the conducting angle or other parameter, are compared.