浅析农村剩余劳动力的转移途径

通过对重庆市农村劳动力质量的现状分析 ,探讨两种农村剩余劳动力转移模式的利弊和可行性。指出通过农业产业的发展带来的农业增长才是实现农村剩余劳动力转移的根本途径     

我国城乡就业存在的问题及解决途径

面对我国农村剩余劳动力增加和城市失业率提高的就业的压力,探讨缓解我国城乡就业压力的途径,即城乡互动,内部吸收,外部转移,政府保障。缓解城乡就业压力的措施是推进小城镇建设,发展非正规部门、非农产业经济,加强基础设施建设,促进教育事业的发展,变消极就业为积极就业。     

万向联轴器法兰叉架的法兰强度计算及厚度确定

分析了万向联轴器法兰叉架的法兰破坏的原因 ,对法兰不同轴向截面进行受力分析 ,提出法兰厚度的计算公式。用这个计算公式可以对承担任何公称扭矩的任何轴向截面的法兰叉架的法兰进行强度计算及厚度确定。     

新型智能扭矩转速传感器及其实验研究

提出了一种新型智能的具有网络通信接口的非接触扭矩转速传感器;通过光电方法精密测量旋转轴的扭转角获得动态扭矩和转速;研究了动态扭矩的温度补偿和初始相位补偿问题;采用神经元芯片Neuron3150处理测试信号和组建传感器的网络通信接口。传感器校准实验结果显示:传感器的测量准确度达到0.4%     

Design of a Drilling Torque Controller for a Machining Center

In the drilling process, cutting torque control through feedrate manipulation has significant benefits in prevention of tool breakage and reduction of machine tool vibration and tool wear. In this paper, a PID torque controller was designed for real time drilling torque control in a machining centre. The drilling torque was estimated from the spindle motor current and regulated by feedrate control. The plant including the feed drive system, cutting process, and spindle system was modelled for controller design. For a certain cutting condition, the Ziegler-Nichols method was used to determine the proportional gain and derivative and integral control action times of the controller. Also, the root locus plot was used to tune the proportional gain of the controller. A simple method was also suggested to obtain the tuned controller gain instead of the Ziegler-Nichols method and the root locus plot for an arbitrary cutting condition. Experimental works have been performed to verify the performance of the proposed controller. It is shown that the gain tuning is essential for enhancement of the controller performance and the designed controller can regulate the drilling torque well at a given reference level.Nomenclature G_fc(s) transfer function of combined system of feed drive and cutting process - G_s(s) transfer function of spindle system - G_p(s) transfer function of plant - G_CL(s) transfer function of closed loop system - G_con(s) transfer function of controller - _fc1, _fc2 time constants of combined system of feed drive and cutting process - _s time constant of spindle system - K controller gain - K_c cutting process gain - K_s spindle motor current gain - K_plant plant gain - K_cr critical gain - K_p proportional gain of controller - K_{p_tune} tuned proportional gain of controller - I_s spindle motor current - I_u,v,w u, v, and w phase current of spindle motor - I_idle idling current of spindle motor - damping ratio - T oscillation period of system response - T_c cutting torque - T_m motor torque - T_idle idling torque of spindle motor - T_i integral control action time - T_d derivative control action time     

EPS快速转向性能对ESC性能影响的分析

目前,ESC系统基本成为汽车的标准配置,ECE R140规定了ESC的性能要求。测试方法中的过度转向干涉正弦延迟测试对方向盘的转速要求较高,EPS在方向盘高转速下的性能对ESC性能测试的影响较大,而在EPS设计时对此和ESC性能的考虑较少。基于此,详细分析ESC的测试性能要求和EPS性能的相关性,对ESC和EPS系统的联合开发及测试提供参考。     

刚度、惯性负载对电液负载仿真台性能影响的研究

为提高电液负载仿真台的性能 ,根据电液负载仿真台的数学模型 ,研究了电液负载仿真台中多余力矩的产生机理和影响因素 ,得出多余力矩干扰与舵机系统轴转角的速度、加速度有关的结论。在分析电液负载仿真台的刚度、惯性负载对系统性能影响的基础上 ,提出了电液负载仿真台的一些设计原则 ,为电液负载仿真台及其它被动加载系统的设计提供了参考依据。     

PHEV模糊逻辑控制策略的建模与仿真

提出了基于模糊逻辑控制扭矩分配策略，建立了各功能组件模型，并利用ADVISOR2002的仿真环境，完成了该模糊逻辑扭矩控制策略和电气辅助控制策略仿真比较。结果表明，此策略对提高混合动力汽车的动力性和燃油经济性、改善排放有明显的作用。     

直接驱动低速横向磁场开关磁阻电机研究

为了提高开关磁阻电机(switched reluctance motor,SRM)的转矩密度,实现低速、大转矩输出,满足伺服和电动车等直接电气驱动系统的要求,提出一种新型横向磁场开关磁阻电机(transverse flux switched reluctance motor,TFSRM)。将横向磁场电机的原理应用于开关磁阻电机,简化电机结构复杂程度,提高电机的转矩密度。详细介绍该电机工作原理及结构特点,运用三维等效磁网络法分析样机定、转子不同相对位置时的磁场分布,计算恒电流控制时电机的矩角特性。设计基于DSP(digital signal processor)的电流闭环控制系统,并对样机进行试验。试验结果与理论分析相吻合,理论分析与设计方法的可行性和有效性得到验证。     

摩托车片式离合器性能综合测试系统

开发了摩托车片式离合器综合测试系统,详细介绍了测试系统的工作原理和技术特点.测试系统采用2台变频电机分别驱动,能够进行静摩擦力矩测量、动摩擦力矩测量,以及离合器分离过程试验, 提出了一种离合器的轴向压紧力的测量方法.利用磁粉制动器和惯性轮,分别模拟摩托车在4°35′坡道上、处于满载常用起步档时折算到离合器的坡道阻力矩和当量惯量,进行离合器耐久试验,试验表明,测试系统可靠性高,测量精度高.