Nonlinearity of Electronic Throttle and Its Control

This paper introduces the development of the electronic throttle control system (ETCS) , the structure and the principle of the system are also involved. After analyzing the nonlinearity problem existing in the mechanical structure of the system, a mathematical model of the ETCS is built up. Then three controllers (PID controller, Fuzzy controller, sliding mode controller) were designed and simulated in the matlab simulink. The result indicates that the PID controller has an overshoot,but the Fuzzy controller and the sliding mode controller can settle the nonlinearity problem better.     

Nonlinear FEM Analysis of RC Staggered Joint by Using APDL Language

In order to settle some problems involved in applying ANSYS into nonlinear Finite Element Analysis of RC structure,this paper discusses the nonlinear FEM method for staggered joint,incorporating its experimental result.The main solved problems are as follows:(1) The fundamental process of nonlinear FEM analysis;(2) How to model the behaviors of reinforcement and concrete respectively;(3) How to model the bond-slip relationship between reinforcement and concrete.     

基于门限自回归的我国羊肉价格波动分析

羊肉价格的适度上涨会刺激我国羊肉产业的发展,但上涨过快,则会损害我国羊肉市场的稳定,对于政策制定者来说,确定羊肉价格大幅上涨的先期指标,以在恰当时机进行合理和适度地调控是非常必要的,可通过建立两体制TAR 模型为政府实施调控的时机提供参考值。选取的羊肉月度价格时间序列样本区间为1994 年6 月至2014 年2 月,TAR 模型估计结果表明,我国羊肉价格同比指数序列门限值为4.678,对应的价格同比指数为107.57%;如果羊肉价格同比指数高于107.57%,羊肉价格波动幅度将会增大,此时会对羊肉市场产生较大冲击,政府需要及时采取调控措施;如果羊肉价格同比指数低于107.57%,那么价格指数的波动相对较为稳定,此时政府不必采取调控措施。另外,政府在制定调控政策时还要充分考虑政策实施效果的时滞性,避免推动羊肉价格产生较大波动。     

基于门限自回归的我国羊肉价格波动分析

羊肉价格的适度上涨会刺激我国羊肉产业的发展,但上涨过快,则会损害我国羊肉市场的稳定,对于政策制定者来说,确定羊肉价格大幅上涨的先期指标,以在恰当时机进行合理和适度地调控是非常必要的,可通过建立两体制TAR模型为政府实施调控的时机提供参考值.选取的羊肉月度价格时间序列样本区间为1994年6月至2014年2月,TAR模型估计结果表明,我国羊肉价格同比指数序列门限值为4.678,对应的价格同比指数为107.57％;如果羊肉价格同比指数高于107.57％,羊肉价格波动幅度将会增大,此时会对羊肉市场产生较大冲击,政府需要及时采取调控措施;如果羊肉价格同比指数低于107.57％,那么价格指数的波动相对较为稳定,此时政府不必采取调控措施.另外,政府在制定调控政策时还要充分考虑政策实施效果的时滞性,避免推动羊肉价格产生较大波动.     

分层正交各向异性板壳非线性有限元分析

采用三维退化等参中厚壳元和分层模型，建立了分析弹塑性和几何非线性各向异性板壳的有限单元法，为克服退化壳元出现剪切和薄膜自锁问题，采用９节点Ｈｅｔｅｒｏｓｉｓ单元并采用选择积分方法，文末算例表明所编程序的可靠性和通用性。     

复杂非线性电阻电路小信号分析法的研究

利用小信号分析法，对复杂线性电阻网络与数个非线性电阻元件联接的电路进行了分析求解，进而得出了复杂非线性电阻电路的一般分析方法。     

Seismic Response Analysis of Transmission Tower-line System under Multi-component Ground Motion Excitations

Seismic responses of power transmission tower-line system under multi-component excitations were analyzed by numerical simulation. A three-dimensional finite element model of transmission tower-line coupled system considering the geometric nonlinearity of transmission line was established. Twelve seismic records of different soil types were selected based on Code for Design of Seismic of Electrical Installations. Seismic responses of power transmission tower-line system under single component, two horizontal component and multi-component excitations were investigated using nonlinear time history analysis method, respectively. The results show that the responses of transmission tower-line system under multi-component excitations are significantly larger than those under single component excitation only, especially for considering vertical ground motion excitation only, and neglecting multiple nature of ground motion in analysis will underestimate the responses of the structure. To obtain an accurate seismic response and a better seismic design of transmission tower-line system, multi-component ground motion inputs need to be considered. The results provide reference for seismic design of transmission line practical engineering.     

非线性惯容器-弹簧-阻尼悬架系统隔振性能分析

以滚珠丝杠式惯容器为研究对象,基于非线性因素对惯容器力流传播过程的影响机理,建立了考虑滚珠丝杠副中的摩擦以及丝杠弹性效应的惯容器非线性力学模型。进行了惯容器的实际力学性能试验,根据试验结果确定了摩擦力的幅值,在此基础上,建立了不含摩擦的惯容器输出力模型,并采用最小二乘递推算法对模型参数进行了辨识。建立了包含惯容器非线性的惯容器-弹簧-阻尼（ inerter-spring-damper ）悬架数学模型,基于Matlab/Simulink和车辆双轴振动模型对ISD悬架性能进行了仿真分析,仿真结果表明,惯容器非线性在一定程度上降低了ISD悬架的隔振性能,但最大降幅不超过10%,同时,相对于三元件并联式ISD悬架,两级串联式ISD悬架不仅表现出较高的综合性能,而且其性能受惯容器非线性的影响程度较小。研究结果可为评估惯容器非线性对ISD悬架性能的影响以及ISD悬架的结构选型提供一定参考。     

渠道运行神经网络控制

针对渠道运行的不确定性和非线性,在渠道自动控制系统的观测器回路上并联一个BP神经网络,通过实测水位的学习,修正控制系统数学模型的不准确性;在控制器增益回路上并联一个BP神经网络,补偿控制增益的不精确。与传统的线性二次调节(LQR)最优控制相比,渠道运行控制过渡过程更为平稳,达到稳定的时间缩短,闸门运行的振动和超调大为改善。     

一类具有变号非线性项的Schr(o)dinger方程的解

利用山路定理讨论了一类带变号非线性项的Schr(o)dinger方程解的存在性.