气动系统元件结构参数对系统结露的影响的研究

气动系统的结露严重影响系统的性能和寿命,正确判别和预防系统的结露是工程实际面临的难题。气动系统的结露和很多因素有关,至今为止没有完善的、简便的判别方法。对1000多种由不同容积的容器和管路组成的气动系统进行了试验研究,提出元件结构参数中影响气动系统结露的主要参数为容器容积V、放气管过流面积A和长度l。引进放气管量纲一的体积和容器出口处量纲一的有效过流面积,对试验结果进行研究的结果表明,放气管量纲一的体积可作为系统是否发生结露和发生何种结露的判据,十分简便易用。以量纲一的体积为横轴,外部结露系统、不结露系统和内部结露系统从左到右依次排列。外部结露区、不结露区和内部结露区的临界点数值与运行条件有关,而与气动元件结构参数无关。     

6A02铝合金压气缸的热处理工艺改进

研究6A02锻铝合金压气缸的热处理工艺参数对6A02铝合金固溶时效处理硬度和抗拉强度的影响,通过采用优化热处理工艺和改进加工尺寸效应,解决了6A02铝合金压气缸硬度偏低的问题。     

气压位置控制系统研究现状及展望

回顾了气压位置控制系统的研究历史,总结了在基本特性研究、控制阀开发和控制策略研究方面的工作。研究工作表明：气体通过阀口和管道的流动复杂、缸内热力过程为指数变化的多变过程、摩擦力与系统运动速度、驱动压力和背压有关。在开发了相关控制阀后,进行了针对系统的各种特性的控制策略的研究,如针对非线性的非线性补偿措施、针对摩擦力的振颤补偿、针对模型误差的鲁棒设计和针对开关阀系统的同向PWM设计等,效果明显。研究工作使得气压位置控制系统已具有良好的性能,能满足工业生产的需要。     

A method of accurate position control with a pneumatic cylinder driving apparatus

In this paper, a method of accurate position control using a pneumatic cylinder driving apparatus is presented. To overcome the effect of friction force and transmission line, low friction type cylinder applied externally pressurized air bearing structure is used and two control valves attached both side of the cylinder directly. To compensate nonlinear characteristics of control valves, linearized control input derived from the relation between control input and effective area of control valve, and dither signal are applied to the valve. The controller applied to the pneumatic cylinder driving apparatus is composed of a state feedback controller and a disturbance observer. Experimental results show that the effectiveness of the proposed method and position control error of 5 μm accuracy could be obtained easily.     

基于自编码器和支持向量机的气压传动系统气缸泄漏故障诊断

气压传动系统在制造领域应用广泛,对智能化故障诊断与节能有较大需求。泄漏是气动系统最常见的故障类型及能量浪费的最主要因素之一。以最具代表性的执行元件气缸为研究对象,通过对其上游压力与流量信号进行处理分析,实现对下游气缸常见的内外泄漏故障的有效诊断。信号特征提取通过栈式自编码器完成,提取的特征进行聚类处理评估后送入支持向量机(Support Vector Machine, SVM)分类器进行分类,从而对气缸泄漏故障进行分类和定位。结果表明：通过分析上游信号来确定下游元器件故障状态是可行的;且对于泄漏故障实验,在同等条件下,基于流量信号的平均分类准确率可达到96%,基于压力信号的平均分类准确率为87%。     

气动单轨吊驱动部设计研究

在煤矿开采中，气动单轨吊运行灵活，无防爆问题，得到较广运用。通过对驱动部结构设计及主要元件的设计选型，对气动单轨吊驱动部进行设计研究。运用FluidSIM软件进行气动系统建模及仿真分析，得到气动马达转速曲线及制动缸活塞位移曲线。利用MATLAB软件编程，得到轨道坡度与载荷关系曲线。结合驱动部运行原理，分析所得曲线，验证设计可以实现所需动作，且系统反应迅速，运行过程中系统压力稳定，符合驱动部所需技术要求。     

ANALYTICAL SOLUTION OF FILLING AND EXHAUSTING PROCESS IN PNEUMATIC SYSTEM

The filling and exhausting processes in a pneumatic system are involved with many factors, and numerical solutions of many partial differential equations are always adapted in the study of those processes, which have been proved to be troublesome and less intuitive. Analytical solutions based on loss-less tube model and average friction tube model are found respectively by using fluid net theory, and they fit the experimental results well. The research work shows that: Fluid net theory can be used to solve the analytical solution of filling and exhausting processes of pneumatic system, and the result of loss-less tube model is close to that of average friction model, so loss-less rube model is recommended since it is simpler, and the difference between filling time and exhausting time is determined by initial and final pressures, the volume of container and the section area of tube, and has nothing to do with the length of the tube.     

Improving dynamic performances of PWM-driven servo-pneumatic systems via a novel pneumatic circuit

In this paper, the effect of pneumatic circuit design on the input–output behavior of PWM-driven servo-pneumatic systems is investigated and their control performances are improved using linear controllers instead of complex and costly nonlinear ones. Generally, servo-pneumatic systems are well known for their nonlinear behavior. However, PWM-driven servo-pneumatic systems have the advantage of flexibility in the design of pneumatic circuits which affects the input–output linearity of the whole system. A simple pneumatic circuit with only one fast switching valve is designed which leads to a quasi-linear input–output relation. The quasi-linear behavior of the proposed circuit is verified both experimentally and by simulations. Closed loop position control experiments are then carried out using linear P- and PD-controllers. Since the output position is noisy and cannot be directly differentiated, a Kalman filter is designed to estimate the velocity of the cylinder. Highly improved tracking performances are obtained using these linear controllers, compared to previous works with nonlinear controllers.     

带卸压槽的微摩擦气缸Fluent仿真分析

针对超低频模态测试悬挂系统中微摩擦气缸抗侧向能力不足的问题,提出一种在活塞尾部增加环形卸压槽的新结构。建立了活塞外表面与气缸内表面之间气膜流场特征参数的仿真模型,并进行Fluent仿真计算,结果表明,增加环形卸压槽改善了气膜的气压分布,在两排节流孔之间形成了具有一定宽度且稳定的承载区,使活塞的轴线与气缸的轴线基本保持平行,提高了抗侧向能力及气膜刚度,从而使气缸工作更为稳定。试验结果进一步验证了仿真结果,证明带环形卸压槽的微摩擦气缸的性能得到了提高。     

Measurement of friction force in pneumatic cylinders

Although the performance and reliability of pneumatic cylinders depend to a great extent on the friction generated at the seals, the friction characteristics have not been widely studied. Both the literature and manufacturers' catalogues rarely discuss the friction characteristics of pneumatic cylinders, and the lack of friction models limits the design, optimisation, and analysis of pneumatic cylinder systems. In seeking to improve the characteristics of pneumatic cylinders and to clarify the friction phenomenon, this paper describes friction force measurement tests carried out in pneumatic cylinders of six different diameters, from 32 to 100 mm. An experimental apparatus was designed to assess the effect of a broad range of operating conditions, where the velocity and pressure of the cylinder chambers are controlled independently. Measurements of friction force are shown for velocities of up to 0.5 m/s and pressures of up to 0.8 MPa. The data obtained will be useful for developing a suitable friction model, and the experimental apparatus will allow study of the effects on the friction force of different types of seal, lubricant, and cylinder barrel.     

A review on recent research trends in servo pneumatic positioning systems

Servo pneumatic systems are widely utilized for obtaining accurate position control in many industrial drives. Such technology has the potential to replace electro mechanical and hydraulic drives in many applications. The main drawback of this technology is the high nonlinear nature of pneumatic drives which affects the system dynamics. It is very necessary to enhance the pneumatic drives by reducing its stochastic nature. The major causes for the non-linearity in pneumatic drives are owing to the pressure dynamics inside the pneumatic cylinder chambers, the frictional force variations and the compressed air flow rates through the valves. In the present study, an endeavor has been made to perform a detailed survey on various aspects in the efficient position control of the pneumatic cylinder. The history, applications, performance tests, component selection, modelling and accurate control of the servo pneumatic systems have also been discussed with the aim to improve the efficiency and the positioning accuracy of the linear pneumatic drive. It has been inferred that a lot of research attentions has to be given for enhancing the performance measures in servo pneumatic positioning systems by reducing the nonlinear nature of the pneumatic systems.     

双滑块机构在爬升机械手中的应用

本机构由两组曲柄滑块机构串接而成,双作用气缸驱动。实现机械手的主爬升运动。本机构结构简单,动作灵活,可以实现正反爬升动作,能在气缸较小的行程内实现大的爬升距离。并具有力的放大作用。给出了机构的结构原理、机构尺度与行程的关系,以及驱动力的计算方法。     

基于等离子体朗缪尔流效应的新型微机械陀螺仪

首次将等离子体作为敏感元件应用于微机械陀螺仪中,取代目前微机械陀螺仪中所采用的固体、液体或气体等元件。利用气体放电产生的等离子体朗缪尔流效应来使敏感元件产生一定速度的运动,不需另外的驱动元件。介绍了等离子体朗缪尔流效应,探讨了应用朗缪尔流效应的新型微机械陀螺仪的原理,根据Langmuir-Drugvesteyn理论推算朗缪尔流速度可达到6 m/s,给出了该新型微机械陀螺仪的微加工与封装方案和工艺参数优化试验系统。     

采用单片机控制的太阳能玻璃管自动环切装置的研究

针对太阳能玻璃管定长切断的工艺要求,开发研制了一种基于单片机控制的太阳能玻璃管自动环切装置.该装置采用一只气缸作为直线往复运动的执行元件,选用步进电动机作为环切刀的驱动器件,应用电磁铁作为对玻璃管的夹持和玻璃刀的定位.控制系统留有低层的信号接口,能很好地与现有玻璃管生产线组合使用.该玻璃管自动环切装置可广泛应用在不同直...     

数控气动爬梯子机器人

提出了一种仿生新型气动的爬梯子消防机器人的设计方案。该方案以气动作为动力,采用单片机控制电磁阀调节气路驱动气缸有序运动,用气缸活塞的运动带动连杆机构运动,来实现机器人自动沿梯子上下爬动,配合摄像头、水枪等消防器具使用,实现高空消防救援的目地。具体分析了该机器人的结构原理、气动系统、电路控制系统的设计。它结构简单,制造成本低,性能可靠。使用表明该控制策略可行、响应快速、控制可靠。因而这种仿生机器人在很多领域有着广泛的应用前景。     

供气压力波动自适应缓冲高速气缸的研究

缓冲是研制高速气缸要解决的关键难题。针对内置缓冲式气缸的缓冲过程建立了数学模型,从吸收能量和冲击能量之间的关系研究供气压力波动对缓冲的影响,仿真结果和试验结果基本吻合。根据分析结果,研制了内置供气压力反馈缓冲结构的新型高速气缸。试验结果表明该新型气缸的缓冲在一定供气压力波动范围内具有良好自适应能力。     

正交增力偏心轮夹紧的气动夹具

介绍了一种基于无杆活塞缸的二次正交增力机构与偏心轮组成的绿色夹具系统,分析了其工作原理和性能特点,给出了夹紧力的计算公式.该夹具能延长气动元件的使用寿命,节能效果明显.对环境的污染小,是清洁的绿色夹具.     

Practical and intuitive controller design method for precision positioning of a pneumatic cylinder actuator stage

The present paper describes a practical and intuitive controller design method for precision positioning of pneumatic cylinder actuator stages. Pneumatic actuators are easy to use and have numerous advantages, which has led to these actuators having a wide variety of applications. However, pneumatic actuators have notable nonlinear characteristics, which make precision positioning difficult to achieve. The purpose of the present study is to clarify a practical and intuitive controller design procedure for precision positioning of a pneumatic cylinder actuator. In addition to positioning performance, the present study focuses on the realization of easy controller design without the need for the exact model parameters or knowledge in control theory for general-industrial-use pneumatic cylinder actuators with friction characteristics. These considerations are important in order to fully exploit the advantages of pneumatic cylinder actuators in a wide variety of applications. As such, three elements are added to the conventional continuous-motion nominal characteristic trajectory following (CM NCTF) controller. A new design procedure of the improved CM NCTF controller for pneumatic cylinder actuator stages is introduced, and the positioning performance of the designed control system is examined experimentally under several conditions. The positioning results generally indicate a positioning error of 50 nm, which is equal to the sensor resolution.     

气缸摩擦力的颤振补偿与仿真

针对气缸摩擦力对系统控制性能造成的不良影响,提出了一种新的摩擦力补偿方法。首先对气缸的摩擦力进行测试分析,然后通过在控制信号上叠加颤振信号来补偿气缸摩擦力,消除了气缸摩擦力对系统稳定性及定位精度的影响。最后通过MATLAB仿真表明所用的补偿方法的正确性和有效性。该补偿方法具有较高的工程应用价值。     

清洗油封一体化试验装置的设计

针对飞机作动筒生产中的清洗和油封要求，应用液压与气动的相关理论，采用PLC及触摸屏构成的电气控制操作系统，设计了自动化程度较高的清洗油封一体化试验装置。这是一个液压与气动相结合的系统，利用活塞式蓄能器存储油封用液压油，通过对不同功能、型号作动筒的一次装夹，完成清洗、油封两道工序的复杂要求，并完成作动筒生产中要求的启动压力特性试验、低压力泄漏试验、耐压试验、内泄试验。试验结果表明：经过对作动筒多次往复的冲洗，生产、组装过程中的杂质得到有效清理，满足飞机对液压元件清洁度的要求。设备大大减轻了操作人员的劳动强度，结构紧凑，人机交互界面良好，功能完善，生产效率及自动化程度较高，具有一定的通用性。