比例调压阀PWM控制气动力感的再现装置

提出一种气动装置以实现在主从式机器手系统中产生力觉临场感。该装置由机械气动结构与PWM控制器两部分组成。详细介绍了力感再现装置力感形成原理与控制方法,搭建了压力修正实验与应力采集实验。实验结果表明,所设计的PWM控制器精确实现了力感驱动气缸的压力控制。该装置用在主从式机器手系统中,能够良好地实现力觉临场感。     

液压控制带压作业试验台研制

研制的液压控制带压作业试验系统由液压起升装置、井口防喷密封装置、管枉接箍探测装置、压力平衡装置、高压流体循环系统、液压动力系统和实验台基础装置组成；采用S7-200型PLC作为液压控制系统的控制器，可以实现模拟带压作业工艺流程试验的自动控制。     

消声器气密性检测装置研制

基于直接压力检测法,推导出了泄漏流量计算公式,设计了检测装置的气动回路.装置中电控部分采用PLC作为控制器,计算泄漏流量并控制装置操作,采用触摸屏输入和显示参数,微型打印机打印检测结果.PLC通过RS232C通讯口与后两者连接.     

减阻装置对厢式货车气动特性的影响

针对某厢式货车的简化模型,基于计算流体力学理论和方法分别对原始货车模型、加装尾部减阻装置和顶部减阻装置的货车模型进行了数值模拟,获得了原始模型与改进模型的气动阻力系数、速度矢量分布、压力分布以及湍动能分布等气动特性。结果表明:尾部减阻装置及顶部减阻装置均可改善厢式货车的气动特性,降低气动阻力。其中顶部减阻装置改善了驾驶室和货厢之间的气流分布,尾部减阻装置改善了货车尾部的涡流状态,从而降低了风阻。     

尾部减阻装置对厢式货车尾部流场的影响

为了降低某厢式货车的气动阻力,基于气动减阻机理设计了9种新型的尾部气动减阻装置。采用数值模拟的方法研究了尾部气动减阻装置对厢式货车尾部流场的影响,对比分析了安装9种尾部减阻装置的厢式货车的气动阻力系数、速度分布、压力分布及湍动能分布等流场特性,并对两种较好减阻装置的结构参数进行优化。研究结果表明:安装9种尾部减阻装置后整车气动阻力系数均有降低,降幅最大为7.96%,获得了较好的减阻效果。尾部减阻装置主要是通过减弱尾部涡流,增大尾部气压,从而来降低压差阻力。     

触点式气功自动测量装置的设计与应用

在主动检测法中采用直接测量装置,对触点式气动自动测量装置的结构设计和工作原理以及在外圆磨削加工中的应用进行了阐述.触点式气动测量装置利用量杆结构上的弹性变形,由光电控制器和光电传感器控制浮动气动量仪,达到自动检测工件的目的.     

基于MIMO滑模的气动伺服系统控制

针对非线性气动伺服系统的轨迹跟踪和柔顺控制问题,采用MIMO滑模控制器实现气动系统多输出的跟踪控制。对气动伺服系统基于流量控制策略的动力学进行建模,将其状态方程转换为严格反馈系统形式;设计用于轨迹跟踪和内腔压力跟踪的双滑模面,基于传统的滑模控制率构造用于气动系统的双控制输入,实现气动系统控制器的设计。基于Simulink搭建控制仿真平台,仿真结果验证了控制器对系统多输出的有效跟踪控制。     

模糊自适应PID控制在润滑油压力气动控制中的应用

针对实验室中某型航空发动机燃油泵调节器润滑油压力控制的需要,设计了一套基于模糊自适应PID控制的润滑油压力气动控制系统。模糊自适应PID控制是将模糊控制原理与常规的PID算法相结合,实现了对PID参数的自适应调整。实验结果表明,该控制器应用于润滑油压力气动控制系统中可取得良好的控制品质。     

基于单纯形法的PID整定及其在气动压力伺服系统中的应用

利用无需计算梯度值的单纯形法进行PID控制器的参数整定,并且巧妙地利用MATLAB最优化工具箱加以实现,避免了复杂的编程计算。将其应用于气动压力伺服系统的控制器设计中,实验结果表明,利用该方法设计的PID控制器响应速度快,超调量小,精度高,完全可以满足气动压力伺服系统的控制要求。     

基于Fluent外混式气动雾化喷嘴改进与仿真研究

为了有效降低喷嘴气体能量的损耗，需要对气动雾化装置整体结构进行雾化速度和压力流场的仿真分析，通过改进局部设计来减少非必要的能量损失，以此来提高气体能量利用率，提升喷嘴雾化性能。为此，对外混式气动雾化装置的内外流场进行了数值研究。首先，对该气动雾化装置内部气相通道进行了数值模拟，找到了原设计中最大能量损失的原因；然后，根据流场的压力和速度分布规律，对壶体与喷嘴连接处的气相通道进行了局部结构改进，分析了装置改进前后内外流场的压力与速度变化情况；最后，通过模拟喷雾过程，对比了不同气压下原喷嘴和改进后的喷嘴内外流场的雾化特性，对喷嘴局部结构改进的合理性与改进后气动雾化装置性能的优越性进行了验证。研究结果表明：通过掏空雾化喷嘴主体和改变雾化喷嘴进气口形状的方式，可以有效改善气相通道的节流情况，减少气体能量的损失，缩短改进后的喷嘴气相通道内部高速气体路径，并且增加喷嘴气相出口附近的流场速度，最大增幅为11.49%;改进后的喷嘴雾化性能得到了提升，当气压在0.3 MPa附近时，其雾化效果最佳。     

Control system design for the mock ventricle with aortic and mitral valve resistance uncertainty

Reproducing the native left ventricle’s contractile behavior is the key ingredient for the mock cardiovascular circulatory system. It can be achieved by controlling either mock ventricle’s pressure or volume so that it could follow the reference signal calculated by the Elastance waveform. However, due to inherent uncertainties of the parameter values of the mock ventricle, such as check valve resistance, it is difficult to achieve high quality control performance. In this paper, we present an adaptive control scheme to overcome this parameter value uncertainty and to achieve high quality control performance. To the best knowledge of the author, it is the first report that reproduces the mock ventricle pumping dynamics precisely considering the resistance of the aortic/mitral check valves and overcoming the uncertainty of them. In the paper, along with the detailed design of the controller, rigorous proof of the stability and the convergence is presented as well. Computer simulation was performed using an electrical-analog cardiovascular circulatory system model and a piston pump mock ventricle model. Results confirmed that adaptive control achieved almost perfect tracking performance in spite of large parameter uncertainty and high bandwidth dynamic characteristics of the mock ventricle. Performance comparison verified the superiority of the adaptive controller over PID controllers.     

Adaptive backstepping slide mode control of pneumatic position servo system

With the price decreasing of the pneumatic proportional valve and the high performance micro controller, the simple structure and high tracking performance pneumatic servo system demonstrates more application potential in many fields. However, most existing control methods with high tracking performance need to know the model information and to use pressure sensor. This limits the application of the pneumatic servo system. An adaptive backstepping slide mode control method is proposed for pneumatic position servo system. The proposed method designs adaptive slide mode controller using backstepping design technique. The controller parameter adaptive law is derived from Lyapunov analysis to guarantee the stability of the system. A theorem is testified to show that the state of closed-loop system is uniformly bounded, and the closed-loop system is stable. The advantages of the proposed method include that system dynamic model parameters are not required for the controller design, uncertain parameters bounds are not need, and the bulk and expensive pressure sensor is not needed as well. Experimental results show that the designed controller can achieve better tracking performance, as compared with some existing methods.     

The possibility of the hydrodynamic evaluation of bio-pumps with the use of a hybrid-digital model of the circulatory system

The paper presents a new prototype of a bio-pump which can support a failing heart; the bio-pump is powered by a skeletal muscle. The typical, mechanical system for circulatory support, need external power sources which are not comfortable for patients and cause infection risk. These advantages of biomechanical support systems show that this kind of support has to be developed. A hydrodynamic evaluation of the prototype was carried out with the use of a hybrid-digital model of the circulatory system. The constructed bio-pump prototype improves the values of pressure in the arterial system, eases volumetrically the left ventricle of the heart, and enhances the end-diastolic and end-systolic parameters of the left ventricle. The hybrid-digital model of the circulatory system is a useful tool for a non-invasive evaluation of the systems which can support the circulatory system.     

Development of a piezoelectric high speed on/off valve and its application to pneumatic closed-loop position control system

The use of smart materials-based high speed on/off valve has exhibited the potential to replace traditional servo and proportional valves in fluid power systems. In this paper, a novel pneumatic high speed on/off valve driven by a piezoelectric stack actuator is developed and its dynamics are studied. For an upstream gauge pressure of 0.5 MPa, the valve exhibited a large flow rate of up to 86 L/min. Furthermore, to study the ability of this novel high speed on/off valve to be applied in closed-loop control systems, a real-time position control system is realized using a PID controller. In order to prove its feasibility and effectiveness, a number of closed-loop trajectory tracking experiments are conducted on a pneumatic cylinder. The system is proved feasible and the results demonstrate good tracking performance.

     

无模型控制器在气缸压力控制系统中的应用研究

气动伺服系统存在纯时延、非线性、时变等特点,传统的控制策略(如PID控制)在解决非线性系统时效果不理想,因此提出一种无模型控制算法。此方法在被控对象结构复杂、参数时变时控制效果较好。首先对气动伺服系统进行建模,建模过程包括阀口流量、比例流量阀及缸内压力建立一个二阶模型;其次设计无模型自适应控制器(Model-Free Adaptive Controller,MFAC)用于气动伺服系统压力控制;最后利用LabWindows/CVI平台进行试验验证。结果表明,针对气动伺服系统设计的无模型控制器是有效的,相比于传统PID控制有更快的响应速度和更高的控制精度。     

高压气动系统负载容腔压力伺服控制仿真研究

为满足某气体发生系统安装空间小、重量轻、动态响应快、控制精度高等要求,设计了高压气动压力伺服控制系统,并采用高压电-气伺服阀实现了负载压力的高响应高精度控制。建立了系统数学模型,包括高压气瓶热力学方程、高压电-气伺服阀传递函数与流量方程、负载容腔压力变化与排气流量方程等子模型,并设计了反馈线性化PID控制器。基于MATLAB/Simulink平台建立了高压气动系统仿真模型,仿真研究了高压气瓶容积与初始气源压力、负载容腔排气孔通径等参数对系统负载压力控制性能的影响规律。研究结果为该系统的优化设计与实验研究提供重要理论依据。     

气力集尘装置变频调节自动控制系统设计

针对家具生产车间的气力除集装置由于生产负荷多变而风机工况调整困难造成能耗高的问题,设计了一种基于压力传感器和变频器的变速调节自动控制系统。该控制系统采用两个压力传感器检测通风总管的负压,以4个开关量将通风主管风压的变化输入给可编程控制器,控制器根据压力偏差程度以多段速方式控制变频器变速,从而实现根据生产负荷变化自动调节风机工况以降低风机能耗的目的。     

用于气动伺服系统的自适应神经模糊控制器

研究了一种基于压力比例阀的气动伺服系统自适应神经模糊控制器。其中的神经网络辨识器（NNI）通过高线训练可以充分逼近非线性动态系统的模型,并能够在线调整模糊控制器的控制规则。系统的位置控制精度和伺服特性有了很大改善。试验结果表明,所提出的控制器对该气动伺服系统具有很好的控制特性以及很强的自适应能力。     

Asymmetric Fuzzy Control of a Positive and Negative Pneumatic Pressure Servo System

The pneumatic pressure control systems have been used in some fields. However, the researches on pneumatic pressure control mainly focus on constant pressure regulation. Poor dynamic characteristics and strong nonlinearity of such systems limit its application in the field of pressure tracking control. In order to meet the demand of generating dynamic pressure signal in the application of the hardware-in-the-loop simulation of aerospace engineering, a positive and negative pneumatic pressure servo system is provided to implement dynamic adjustment of sealed chamber pressure. A mathematical model is established with simulation and experiment being implemented afterwards to discuss the characteristics of the system, which shows serious asymmetry in the process of charging and discharging. Based on the analysis of the system dynamics, a fuzzy proportional integral derivative (PID) controller with asymmetric fuzzy compensator is proposed. Different from conventional adjusting mechanisms employing the error and change in error of the controlled variable as input parameters, the current chamber pressure and charging or discharging state are chosen as inputs of the compensator, which improves adaptability. To verify the effectiveness and performance of the proposed controller, the comparison experiments tracking sinusoidal and square wave commands are conducted. Experimental results show that the proposed controller can obtain better dynamic performance and relatively consistent control performance across the scope of work (2–140 kPa). The research proposes a fuzzy control method to overcome asymmetry and enhance adaptability for the positive and negative pneumatic pressure servo system.     

气动肌肉关节的刚度分析及变刚度运动控制

根据人腿髋关节、膝关节骨骼结构及拮抗肌肉运动发力特点,设计一种拮抗气动肌肉驱动的仿生单腿机器人;由三元素模型求单根肌肉及关节摆动下被动刚度特性,分析关节角度/刚度关系;为实现仿生腿膝关节刚度可控的角度控制,建立仿生关节关于角度/刚度的基本气压解算模型;基于计算力矩控制对非线性对象具有高度补偿线性化性,提出含力矩项补偿的改进气压解算模型。搭建仿真及样机实验平台,结果表明,含两种气压解算模型的双闭环控制算法均能较好跟随膝关节角度/刚度,含带力矩项补偿模型的双闭环控制算法对膝关节的角度/刚度控制精度优于含基本模型的双闭环控制算法。该算法适用拮抗气动肌肉关节的类人运动,可满足人机协作时可靠性、柔顺性、仿生性等要求。