膜片式气制动阀静动特性

对我国拖拉机挂车气制动系主要控制元件之一—膜片式气制动阀静动特性做了理论分析和试验研究,通过适当改变气制动阀内部参数的方法,提高了其静动特性指标和拖拉机挂车机组的制动性能。试验表明气制动阀静特性不仅与几何尺寸、平衡弹簧刚度、输入气压及行程有关,还与制造精度、装配质量、调整误差有关,气制动阀的动特性不仅与平衡弹簧刚度有关,而且还与进气阀口内径和阀座硬度有关。     

膜片弹簧式气制动阀动特性的研究

对我国拖拉机挂车气制动系主要控制元件之一——膜片弹簧式气制动阀动特性做了理论分析和试验研究，通过适当改变气制动阀内部参数的方法，提高了其动态特性性能指标。提高了拖拉机挂车机组的制动性能。试验表明膜片弹簧式气制动阀的动特性不仅与平衡弹簧刚度有关，而且还与讲气阀口内释和径座硬度有关。     

膜片弹簧式气制动阀静特性的研究

膜片弹簧式气制动阀作为控制阀已广泛地应用于拖拉机挂车制动系统。气制动阀静特性直接影响拖拉机挂车机组的制动性能。对我国拖拉机挂车气制动系主要控制元件——膜片弹簧式气制动阀静特性做了理论分析和试验研究,表明气制动阀静特性不仅与几何尺寸、平衡弹簧刚度、输入气压及行程有关,还与制造精度、装配质量、调整误差有关。     

拖拉机挂车气制动阀静特性的研究

对拖拉机挂车气制动系统主要控制元件之一－－活塞式和膜片式气制动阀的静特性做了理论分析和试验研究,表明活塞式和膜片式气制动阀静特性不仅与几何尺寸、输入力和行程有关,还与制造精度、装配质量和调整误差有关。     

喷涂机器人手臂静动特性研究

近年来我国机器人技术的研究发展较快,相继研制出各种各类工业机器人。从我国研制机器人的产品来看,大多数是仿制国外同类产品,尚未形成一个完整的机器人操作机的设计方法。对于机器人而言,机器人手臂是其关键部件,所以对机器人手臂性能的研究是保证机器人性能的主要问题。本文以喷涂机机器人为例,研究机器人手臂的动、静特性。     

拖拉机挂车制动气室的研究

我国拖拉机挂车气制动执行机构主要采用膜片的制动气室，对其推力进行理论分析和试验研究后，得出膜片式制动气室推力不仅与几何尺寸和气压有关，还与工作行程有关。     

制动气室有效承压面积的探讨

我国拖拉机挂车气制动系统执行机构主要采用膜片式制动气室,对拖拉机挂车机组气制动系的制动性能完全满足强制性国家标准GB16151-2008《农业机械运行安全技术条件》和GB7258-2004《机动车运行安全技术条件》中规定要求的膜片式制动气室有效承压面积进行理论分析和试验研究后,得出膜片式制动气室有效承压面积不仅与几何尺寸和气压有关,还与工作行程有关.试验按照国家行业标准JB/T9840.1-1998《拖拉机挂车气制动系统制动气室技术条件》进行,找到了膜片式制动气室有效承压面积的变化规律.膜片式制动气室有效承压面积不是一个固定不变的数值.指出了不同型式的膜片式制动气室推杆有效工作行程范围.     

拖拉机组制动系统的协调控制措施

针对拖拉机机组中常见的液-气混合制动系统(拖拉机为静液压制动,挂车为气压制动),探讨了液-气混合制动系统的协调控制措施及典型解决方案.     

客车车身及车架的静动特性分析

本文介绍了用有限元法对客车车身进行静力分析和动力分析的方法 ,探讨了分析结果在车身改进设计中的应用。对HB6 790客车进行的计算分析及试验表明 ,文中所涉及的建模和分析手段是行之有效的。     

先导式气动截止阀的设计

论述了自动控制截止阀的工作原理，以实例计算分析了先导式气动截止阀的特点。     

考虑电磁特性的电磁开关阀动静态性能仿真研究

为研究电磁特性下电磁阀的动静态性能,针对设计中使用到的电磁开关阀,首先分析了电磁铁的结构参数和电磁开关阀动力学模型,然后应用Ansoft Maxwell和AMESim建立了电磁开关阀仿真模型,对不同占空比以及不同频率下的脉宽调制(PWM)输入控制信号进行了仿真,分析了其动态响应过程及静态性能(空载流量、空载压力等),最...     

Performance improvement of pneumatic artificial muscle manipulators using magneto-rheological brake

A novel pneumatic artificial muscle actuator (PAM actuator), which has achieved increased popularity to provide the advantages such as high strength and high power/weight ratio, low cost, compactness, ease of maintenance, cleanliness, readily available and cheap power source, inherent safety and mobility assistance to humans performing tasks, has been regarded during the recent decades as an interesting alternative to hydraulic and electric actuators However, some limitations still exist, such as the air compressibility and the lack of damping ability of the actuator bring the dynamic delay of the pressure response and cause the oscillatory motion Then it is not easy to realize the performance of transient response of pneumatic artificial muscle manipulator (PAM manipulator) due to the changes in the external inertia load with high speed In order to realize satisfactory control performance, a variable damper — Magneto-Rheological Brake (MRB), is equipped to the joint of the manipulator Superb mixture of conventional PID controller and a phase plane switching control method brings us a novel controller This proposed controller is appropriate for a kind of plants with nonhnearity, uncertainties and disturbances. The experiments were carried out in practical PAM manipulator and the effectiveness, of the proposed control algorithm was demonstrated through experiments, which had proved that the stability of the manipulator can be improved greatly in a high gain control by using MRB with phase plane switching control method and without regard for the changes of external inertia loads     

注塑机械手机身振动特性分析与动力学分析

注塑机械手床身是机床的重要基础部件,它的动态特性和静态特性直接影响注塑机械手稳定性。以某注塑机械手为研究对象,采用Pro-E Wildfire 3.0建立机械手床身的三维实体模型,借助大型有限元软件ANSYS建立机械手的有限元模型,对其进行网格划分、边界条件加载和求解计算,在有限元的后处理中进行协响应分析与瞬态动力学分析。根据有限元分析结果,得到各阶响应的时间-位移曲线和振幅频率特性曲线,为改进注塑机械手机身受力状况和结构优化设计提供理论依据。     

比例阀控气动伺服系统的建模与仿真研究

介绍了比例阀控气动伺服系统的工作机理;通过对该系统元件特性的分析,推导并建立了该系统的数学模型.采用比例控制的方法,对系统进行了仿真,得到了模型在低频工作频段内的动态响应.     

A bulk-flow analysis of static and dynamic characteristics of floating ring seals

The bulk-flow model was used to calculate the static and the dynamic characteristics of floating ring seals because the solutions based on the numerical integration of the complete Navier–Stokes equations can be very time consuming. A steepest-descent method is used to find the seal's equilibrium position efficiently. The bulk-flow model is governed by three partial differential equations on eccentric working conditions. A finite-difference scheme has been used to solve the nonlinear governing equations. Compared to Nelson and Nguyen's fast fourier transform method, this scheme has better consistency. Perturbation analysis of the flow variables yields a set of zeroth and first-order equations. The SIMPLE algorithm is used to integrate the system of bulk-flow equations. Comparisons of the numerical predictions (lock-up eccentricity ratio, leakage flow rate and rotordynamic coefficients) with Ha's results, which were formulated using the Fourier series, and experimental data are presented subsequently.     

Measurement of flow rate characteristics of pneumatic components based on the dynamic regularity of polytropic exponents

To improve the measurement precision of flow rate characteristics of pneumatic components, a new measurement method is proposed, which is based on the dynamic regularity of instantaneous polytropic exponents during discharge. The dynamic regularity of polytropic exponents is obtained by the stop method, and it can be concluded as two change stages based on pressure time constant. According to piecewise polynomial fitting curves of instantaneous polytropic exponents, a new algorithm for the identification of flow rate characteristics is proposed. This method can accurately measure some components with a large sonic conductance and a small critical pressure ratio. Four pneumatic components are measured to compare the identification precision of those different methods. The results of comparison show that the new polytropic exponent method and its new algorithm have the higher precision than other alternative methods for the ISO6358 method. The identification errors of sonic conductance of the new method are less than 3%, and the identification errors of critical pressure ratio of the new algorithm are less than 15%.     

Investigation on the dynamic characteristics and control accuracy of a novel proportional directional valve with independently controlled pilot stage

The pilot operated directional valves are widely used in hydraulic systems. For the purpose to improve the dynamic characteristics and control accuracy of the traditional valve, this paper proposes a novel pilot valve that employs two independent valve spools instead of the traditional port coupled valve spool. Due to the new structure, the influence of deadzone and damping on the performance of the valve is lightened; the dynamic characteristics and control accuracy of the valve are improved. Both of the open-loop simulation and experimental closed-loop position control of the entire valve demonstrate that the novel valve has impressive performance improvement of the entire valve. The results of experiments show that the -3dB-frequency of novel valve improves 61.5% in the case of single side control mode (SS) and 57.1% in the case of both side control mode (BS); the tracking error decreases from 6.21% to 2.6% in the case of SS and from 7.48% to 3.96% in case of BS.