农机用负载敏感系统故障分析及优化仿真研究

阐述了农机常用的LS及LUDV负载敏感液压系统的工作原理,利用AMESim仿真软件建立其仿真模型,对两者动态特性及故障现象进行仿真分析.针对LUDV负载敏感液压系统缺点,设计了一种新的支路并联压力切断阀的LUDV负载敏感液压改进系统.仿真结果表明:改进后的LUDV负载敏感系统,能够有效解决系统工作支路卡死或者运动到行程...     

介绍一种压差补油增压缸增压回路

在一般夹具增压缸增压回路的设计和应用中,都要附带补油箱(图1),以补偿增压支路工作时产生的微量内泄漏。我们通过实践,设计的压差补油增压缸增压回路,以简单压差补袖支路代替了造价高于其数倍的补油箱,缩小了液压系统的占用空间,使整个液压系统的结构和工作性能更加紧凑。     

一种液压增压缸的应用

为节省能源消耗,介绍一种增压回路,用于提高机床液压系统中某一支路工作压力,以满足局部工作机构需要.     

一种带式传输装置智能控制系统的设计

以补偿带传输装置的液压系统压力损失、提高带传输装置的稳定性为目标,设计一种能够改善液压系统压力损失的智能补偿系统。阐述带传输装置的结构与工作原理,利用FLuidSIM软件对其进行仿真分析。利用比例换向阀、传感器设计一种具有比例反馈环节的智能压力补偿系统。利用AMESim分别建立普通带传输系统与智能补偿带传输系统的仿真模型。仿真结果表明：在相同的工作压力下,智能补偿系统可对带传输系统进行有效的压力损失补偿,保持带传输装置所需压力的稳定供给。     

开中心式负载传感系统在甘蔗收割机的应用研究

甘蔗收割机在工作过程中能耗很大。为了减少甘蔗收割机液压系统中的压力损失,该文对采用调速阀和三通压力补偿阀的两种压力补偿系统的静动态特性进行了分析研究。结果表明:三通压力补偿阀系统能够根据负载的变化实时调整系统压力,从而有效地减少甘蔗收割机液压系统在工作过程中的压力损失。在相同工况下,其功率损失比调速阀压力补偿系统少46%左右。     

密炼机转子端面密封装置增速及同步性能提升研究

为解决密炼机转子密封处容易出现的渗漏故障,对X（S）M系列密炼机现有的转子端面密封装置方案的液压系统进行了增压方案、增速方案、多缸工作控制技术设计,首先进行在增大压力后的增加速度设计,以补偿因增压导致的工作速度降低,接着考虑4个以900间隔方式排列的液压缸同步动作,在四个点位均匀施压,保证密封效果,以全面提升密炼机液压机构工作性能。     

一种深海液压系统压力补偿装置的建模与应用

设计了一种应用于深海环境的液压系统的压力补偿装置,在分析其工作原理的基础上,对压力补偿过程进行了建模与分析。结果表明,硅油补偿体积与水压成单调递增的函数关系,从而为压力补偿装置的设计提供了定量的依据。根据此设计依据研制的压力补偿装置在深海热液pH值原位探测器上得到了成功的应用,从而证明了该压力补偿装置设计方法的正确性和有效性。     

基于 AMESim 飞机液压能源系统用户可用压力仿真计算

对飞机液压能源系统中存在的压力损失进行了理论分析,并运用AMESim软件建立了飞机液压能源系统元件、管路以及用户的流量压降模型。基于仿真模型对典型飞行阶段液压能源系统各用户支路的压力损失进行仿真计算。该仿真分析模型可用于飞机液压能源系统用户可用压力计算。     

基于AMESim飞机液压能源系统用户可用压力仿真计算

对飞机液压能源系统中存在的压力损失进行了理论分析,并运用AMESim软件建立了飞机液压能源系统元件、管路以及用户的流量压降模型。基于仿真模型对典型飞行阶段液压能源系统各用户支路的压力损失进行仿真计算。该仿真分析模型可用于飞机液压能源系统用户可用压力计算。     

杠杆、死点脱离式助力机构在剪式升降车中的应用

基于杠杆原理、死点原理设计了一种适用于剪式手动液压升降车的助力机构。该设计主要是为降低升降车在最低点时的液压系统压力,针对这种特殊结构建立了助力机构的数学模型,通过该数学模型计算出助力机构能够将升降车在最低点时液压系统压力降低70%以上,并通过数据对比及实物样机验证了该机构的合理性。     

单兵武器系统协同仿真方法

为提高单兵武器系统整体设计性能,缩短设计周期,在内弹道仿真、外弹道仿真及人枪相互作用仿真模型二次开发的基础上,采用基于接口的协同仿真技术,建立了单兵武器系统协同仿真模型.通过对单兵武器系统协同仿真模型的研究,获得了单兵武器系统整体性能参数,并验证了协同仿真技术的有效性.该研究为单兵武器系统的仿真研究提供了新的思路.     

外骨骼装备在未来单兵系统中的应用前景

当前世界上很多国家为了应对新军事变革,都在制定和实施未来单兵系统的发展计划,抢占军事制高点,由于这些系统融入了各种先进的军事装备,士兵的负重也大大增加,不利于任务的及时完成,外骨骼装备的出现及应用将改变这种局面.外骨骼装备既可以为士兵增强负重能力,也可以作为一个非常不错的武器搭载平台,通过集成多种先进武器装备使普通士兵成为一个强大的作战单元,同时无需考虑过多的负重对士兵的影响.外骨骼装备将在未来单兵系统中起到重要作用,具有广阔的应用前景.     

浅谈工业机械手设计

介绍了工业机械手设计,包括机械设计,气动传动系统设计,电气控制系统设计等部分.四自由度,抓重为50N的圆柱坐标工业机械手,由气压系统驱动,工作循环由PLC控制,可以通过改变程序来改变动作循环的顺序,其动作有手臂的伸缩、旋转、上升,手腕的回转和手指的夹紧放松等五部分.     

箔带轧制的三维接触有限元分析

基于对三维多体接触问题有限元混合法基本原理及接触面的定解条件和判定条件的分析 ,本文将箔带轧机辊系及轧件组成的辊带系统视为三维多体接触问题 ,建立了接触有限元分析模型。对某厂四辊铝箔轧机初轧工况进行了数值计算 ,求得了辊缝内轧制压力的真实分布规律 ,充分揭示了箔带轧制过程中非轧制辊面存在压靠的事实。最后 ,针对来料板凸度对轧件板形的影响进行了有限元仿真分析 ,得出了与轧制规程图分析法一致的结论     

Small-scale in vivo imaging of soft tissues by radioscopy using single X-ray photon counting

A method has been developed for routine laboratory visualisation of small‐scale soft tissue by means of transmission X‐ray radioscopy and tomography. Using termites as models, imaging quality with a spatial resolution of about 3 μm was achieved and 3D tomographic reconstruction was demonstrated. A termite worker individual was visualized before and after its metamorphosis towards the soldier caste. The developed methodology represents a non‐invasive and real‐time way of acquiring 3D anatomic data with a high contrast so that it is a promising candidate to become a tool for routine investigations in life sciences.     

Comparison study of a cluster of four dynamic flow pattern discrimination techniques for multi-phase flow

Four frequently used measurement methods for flow pattern discrimination were identified, developed and implemented in the constructed vertical experimental system. This computer-aided experimental system (CAES) was used to generate all typical flow patterns in vertical flow and measure all chosen dynamic parameters (concentration, pressure, and interfacial phenomenon) simultaneously and in the same space. In this CAES, the flow pattern discrimination system is composed of the application of two different electromagnetic methods (capacitive and resistive), a static pressure method and an optical method. In the reported experimental research on adiabatic air–water flow in a circular vertical channel, results were obtained using a cluster of four chosen measurement systems simultaneously. The results allowed a direct comparison of the ability of each method in terms of application as a flow pattern discriminator. The different abilities of individual methods to detect flow patterns were documented and discussed.     

Note: Mechanical and electrical characterization of nanowires in scanning electron microscope

This note presents two experimental techniques for mechanical and electrical characterization of individual nanowires inside a scanning electron microscope (SEM). Tensile testing is realized by transferring a nanowire to a microelectromechanical systems device that stretches the nanowire and measures the elongations and tensile forces. The device consists of an electrostatic actuator and two capacitive sensors, capable of acquiring all measurement data (force and displacement) electronically without relying on electron microscopy imaging. For electrical characterization, four-point probe measurement of individual nanowires is performed automatically by controlling four nanomanipulators with SEM visual feedback. A feedforward controller is incorporated into the control system to improve the response time. This work represents advances in nanomaterial testing and automated nanomanipulation.     

Sensory structures on the antenna of soldier and worker castes of the termite species Odontotermes parvidens (Termitidae: Isoptera: Blattaria)

Odontotermes parvidens is a commonly found important pest species of termite that primarily feed on a range of cellulosic sources. In termites, communication among the nestmates is the basis of all their daily activities and the sensory structures present on the sensory appendages play a crucial role in different social behaviors perceiving and processing various signals of the nestmates and external environments. So, it is essential to understand in detail their sensory structures in order to understand the sensory system of the species O. parvidens. Thus, we have studied the antenna which is one of the primary sensory appendages of both soldier and worker individuals of the species to elucidate various antennal sensory structures and their distribution using scanning electron microscopy. Based on the morphological features of various sensilla, we observed seven types of sensilla as sensilla chaetica (subtypes I, II, III, and IV), sensilla trichodea (subtypes I and II), sensilla trichodea curvata (subtypes I and II), sensilla basiconica, sensilla capitula, Böhm bristles, and sensilla campaniformia (subtypes I and II) along with numerous glandular pores on the antenna of soldier and worker castes. We have also discussed the putative functions of all the sensilla observed based on their external morphology and distributional characteristics on the antenna of soldier and worker castes of the species O. parvidens. Furthermore, the abundance of sensillar types on the antenna of both the castes has also been discussed.     

基于慧鱼模型纽扣式电池检测系统的设计

纽扣电池作为电池的一类,它有着不可替代的地位和较广的应用范围。而传统的纽扣电池检测方式却是单一、低效的,且不合格电池使用率较高。为了能够提高电池检测的工作效率,降低不合格电池的使用率,同时改善电池的检测方式,设计了一个代替传统检测电池方式的作品。利用送料装置、检测装置和接料装置这三个分支结构来完成整个系统的工作,从而达到检测的目的。通过这个系统的设计,可以使电池检测过程中的不合格率降低,检测更连续,人工检测的弊端得以消除。     

Laminar flow in the gap between two rotating parallel frictional plates in hydro-viscous drive

The velocity,pressure and temperature distributions of the flow in the gap between hydro-viscous drive friction disks are the key parameters in the design of hydro-viscous drive and angular velocity controller.In the previous works dealing with the flow in the gap between disks in hydro-viscous drive,few authors considered the effect of Coriolis force on the flow.The object of this work is to investigate the flow with consideration of the effects of centrifugal force,Coriolis force and variable viscosity.A simplified mathematical model based on steady and laminar flow is presented.An approximate solution to the simplified mathematical model is obtained by using the iteration method assuming that the fluid viscosity remains constant.Then the model considering the effect of variable viscosity is solved by means of computational fluid dynamics code FLUENT.Numerical results of the flow are obtained.It is found that radial velocity profile diverges from the ideal parabolic curve due to inertial forces and tangential velocity profile is nonlinear due to Coriolis force,and pressure has two possible solution branches.In addition,it is found that variable viscosity plays an important role on pressure profiles which are significantly different from those of fluid with constant viscosity.The experimental device designed for this work consists of two disks,and one of them is fixed.Experimental pressure and temperature of the flow within test rig are obtained.It is shown that the trend of numerical results is in agreement with that of experimental ones.The research provides a theoretical foundation for hydro-viscous drive design.