基于8051的公交车自动门系统的设计

随着科技的发展,人们对生活质量的要求也越来越高,生活的很多领域都开始实现自动化、智能化,公交车自动门系统就是其中之一。本文设计了基于单片机的公交车自动门,主要应用8051作为控制主体,直流电机、PWM调速、转速测量为核心,直流电机采用双极性H桥驱动,磁开关等相结合。通过程序对直流伺服电机的正转、反转进行控制,从而对门进行开、关的控制;通过检测电机转速,测得转速为零时向单片机发出堵转信号,从而自动开门,并发出事故报警提醒驾驶员,形成了防挤压功能,充分发挥了单片机的性能。加入关门后发出报警声,提示乘客汽车即将启动,提高了乘客安全进出的保证,实现了公交车门安全的自动控制。     

8098单片机定量输送泵控制器

本文介绍了利用８０９８单片机组成定量输送泵控制器的方法，给出了检测电机转速及直流电机调速的硬件电路。     

直流电机转速及电流检测显示系统设计

直流电动机的控制需要检测实时转速、电流等信息,本文设计了一个单片机采样显示系统,包括电流传感器、速度传感器检测电路的设计、显示电路设计,在此硬件平台上对直流电机进行了闭环控制,实验结果表明所设计系统的有效性,为小型直流驱动系统的硬件设计提供一种方案。     

直流无刷电机对机器人行走机构的控制

设计系统以直流无刷电机专用集成控制芯片MC33035为主控制器,通过软件编程实现由AT90S8535单片机输出控制器所需要的PWM波,实现对直流电机转速的控制,近而实现对机器人行走机构的控制.设计系统大大简化了硬件电路,被广泛应用于机器人的行走机构的控制.     

基于Proteus智能小车的仿真设计

以AT89C52单片机为核心设计无线遥控小车控制系统。本系统主要包括单片机最小系统模块、按键模块、无线收发模块、直流电机驱动模块和舵机转向模块。按键输入舵机、直流电机控制指令,单片机处理后产生PWM脉冲控制小车的转向和直流电机驱动脉冲,经L298电流放大后驱动直流电机,数码管实时显示直流电机的运行状况。并通过Proteus仿真小车的启动/停止、加速、减速、反向及转向等功能。     

基于单片机的直流电机数字控制系统研究

本设计介绍了基于单片机控制的PWM直流电机调速调向系统,系统以STCl2C5A08S2单片机为核心,模型直流电机为控制对象,并采用独立键盘输入有关控制信号,以实现直流电机的启停、正反转、加速减速、急停等功能。同时在系统中加入了过热保护模块,解决了系统由于长时间工作高温而造成的元器件损坏问题。     

基于单片机的直流电机控制系统在动态送风装置中的应用

介绍一种基于单片机的动态送风控制系统。该控制系统以C8051F330单片机为处理器，配合控制电路，采用脉宽调制技术，根据自然风特性，对直流电机的转速进行控制，从而实现风机出风的动态化。     

基于 STC 单片机的直流电机调速系统设计

根据巡线避障小车用的直流电机的具体要求,本文设计了以 STC12C5A60S2单片机为核心控制单元器件,运用 STC12C5A60S2单片机的 PWM模块结合 L9110加外围元器件电路来驱动直流电动机,运用红外槽型开关检测电路结合单片机计数器功能来检测电动机的实时转数,通过按键设定转速,通过PID 控制算法实现电机速度调节。模拟结果证明该系统具有精确、可靠、调节方便、稳定性高等特点。     

智能自动避障小车设计

本文介绍了一种智能自动避障小车的设计方法,采用8位单片机STC80C51对直流电机控制,通过I／O输出的脉冲作为直流电机的控制信号,同时采用红外传感器检测前方的障碍物并通过相关程序实现避障功能,用汇编语言实现其设计。     

采用模糊控制的直流电机软启动及调速系统

介绍了以单片机为核心的直流电机软启动及调速系统,系统采用模糊控制策略,将转速偏差与偏差率模糊化并作为模糊控制器的输入量,根据所制定的模糊控制规则生成控制量。实验结果表明,该系统启动时间可以根据需要调整,具有良好的静态和动态性能。     

Analysis of a Premature Failure of a Hub from a Diesel Generator of a High-Speed Motor Ship

Failure analysis is carried out on a fractured hub obtained from a diesel generator of a high-speed motor ship. Macrofractography, microfractography, standard optical metallography, material characterization techniques, and numerical modeling were used to verify the findings of the current investigation. Cracking initiation is attributed to fretting fatigue caused by a modification performed in the vicinity of the fractured hub. Operational vibrations contributed to the propagation of the cracks as typical fatigue cracks until final fracture.     

Resistance of a sphere in a slow flow of a viscoelastic fluid

The authors have obtained an approximate solution of the problem of the resistance of a rigid sphere in a slow flow of a Maxwell viscoelastic fluid that is in good agreement with experimental data [1] for Weissenberg numbers We ≤ 0.7. It is shown that the effect of a decrease in the coefficient of resistance of a sphere in the interval 0.1 ≤ We ≤ 0.7 established experimentally is determined in full measure by the linear viscoelastic properties of the Maxwell fluid. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 71, No. 6, pp. 1138–1140, November–December, 1998.     

Dispersion of a solute in a Poiseuille flow of a viscoelastic fluid

Gill and Sankarasubramanian's analysis of the dispersion of Newtonian fluids in laminar flow between two parallel walls is extended to the flow of non-Newtonian viscoelastic fluids (known as Phan-Thein-Tanner (PTT)). Using a generalized dispersion model which is valid for all times after the solute injection, the diffusion coefficient K_i(t) is obtained exactly and numerically for linearized and exponential forms of the PTT fluids, respectively. The analysis leads to the novel result for K₁ and K₂(t) (which is a measure of the longitudinal dispersion coefficient of the solute). It is found that the value of K₂(t) depends on the value of Deborah number (De=a measure of the level of elasticity in the fluid) whereas the value of K₁ is constant in both cases. Finally, the effect of the Deborah number on the axial distribution of the mean concentration θ_m is investigated in detail.     

聚醚砜四元制膜液体系的相图计算

以Ｆｌｏｒｙ－Ｈｕｇｇｉｎｓ理论为基础，对ＰＥＳ－ＰＧ－ＮＭＰ＿Ｈ２Ｏ＿）聚醚砜丙二醇－Ｎ－甲基－２－哟咯烷酮水）四元制液体系的相图进行了计算，利用三元相图考察Ｈ２Ｏ和ＰＧ对液－液相分离的影响，在三元的理论的基础上提出了低分子量添加剂的卤元改性Ｆｌｏｒｙ－Ｈｕｇｇｉｎｓ理论，并提出了一种获得四元相图的方法，利用四元相图能较争地描述四元体系，利用改性的四元理论，能了地理解该种体系的液－液相分离行为。     

Flow of a thin film of a viscous liquid in a gas jet

An approximate formulation is considered for the steady-state wave flow of a thin film of viscous liquid subject to tangential frictional stresses at the boundary. Measurements have been made on the stability limit for droplet detachment, and it has been found that the detachment rate and fractional composition of the droplets are dependent on the boundary conditions.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 40, No. 4, pp. 622–630, April, 1981.     

Drag of a plate in a uniform flow of a weak polymer solution

The problem of the drag of a plate moving in a weak polymer solution is solved on the basis of a three-layer schematization of the velocity distribution in the turbulent boundary layer.Translated from Inzhenerno-Fizicheskii Zhurnal, Vo. 41, No. 5, pp. 819–826, November, 1981.     

Heat exchange of a swirled stream of a gas suspension in a pipe

The results of an experimental investigation of heat exchange during turbulent flow of a gas containing suspended particles of a solid material in a horizontal pipe are presented.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 51, No. 2, pp. 198–202, August, 1986.     

Heat Transfer of a Sphere in a Constrained Flow of a Viscous Fluid

Results of an experimental investigation of the average heat transfer of a sphere in the region of Reynolds numbers 0.1–40 are given. The increase in the Nusselt number with increase in the constraint parameter of flow is established. Based on the fractal theory, the influence of the degree of constraint on the heat transfer is physically explained and a quantitative correction is introduced.     

Calculation of a transient in a two-pole network with a thermistor

An analytical expression is derived which describes the variation of the thermistor temperature during a relay-effect transient process following an instantaneous change in the supply voltage in an R — R_T two-pole network.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 38, No. 3, pp. 465–472, March, 1980.