The problem considered is an initially stressed viscoelastic cable with small sag. The cable material is assumed to be constituted by the hereditary differential type. The partial differential equations of motion is d...The problem considered is an initially stressed viscoelastic cable with small sag. The cable material is assumed to be constituted by the hereditary differential type. The partial differential equations of motion is derived first. Then by applying Galerkin's method, the governing equations are reduced to a set of third order nonlinear ordinary differential equations which are solved by Runge-Kutta numerical integration procedures. Only after the transverse vibration of the plane is considered and the nonlinear terms are neglected, can the nonlinear ordinary differential equations be expressed as a continuous state equation in the state space. The matrix of state transition is approximated stepwise by the matrix exponential; in addition, the state equation is discretized to a difference equation to improve the computing efficiency. Furthermore, an optimal control of procedure system based on the minimization of a quadratic performance index for state vector and control forces is developed. Finally, the effect of dynamic response of the cable, which is produced by viscoelastic parameters, is testified by the research of digital simulation.展开更多
舰船动力设备系统产生的持续低频振动会严重影响舰船的声隐身性能及舰船精密设备的工作性能。以自主设计研制的电磁主动吸振器为对象,为了匹配电磁主动吸振器的实际使用工况,在滤波-x最小均方(Filter-x Least Mean Square,FxLMS)控制算...舰船动力设备系统产生的持续低频振动会严重影响舰船的声隐身性能及舰船精密设备的工作性能。以自主设计研制的电磁主动吸振器为对象,为了匹配电磁主动吸振器的实际使用工况,在滤波-x最小均方(Filter-x Least Mean Square,FxLMS)控制算法中引入抑制因子,对主动控制力的输出进行限幅。首先通过数值仿真分析验证匹配优化后的控制算法对振动控制的抑制效果,然后介绍基于电磁主动吸振器工程样机搭建的主动控制实验台架系统,以单频激励工况为基础开展主动控制效果验证实验,证明电磁吸振器与匹配优化后的控制算法对低频机械振动控制的有效性。数值仿真和实验结果表明,针对自主设计研制的电磁主动吸振器而提出的匹配优化主动控制算法能够有效抑制低频机械振动响应,在时域和频域均可以取得显著的振动控制效果。展开更多
文摘The problem considered is an initially stressed viscoelastic cable with small sag. The cable material is assumed to be constituted by the hereditary differential type. The partial differential equations of motion is derived first. Then by applying Galerkin's method, the governing equations are reduced to a set of third order nonlinear ordinary differential equations which are solved by Runge-Kutta numerical integration procedures. Only after the transverse vibration of the plane is considered and the nonlinear terms are neglected, can the nonlinear ordinary differential equations be expressed as a continuous state equation in the state space. The matrix of state transition is approximated stepwise by the matrix exponential; in addition, the state equation is discretized to a difference equation to improve the computing efficiency. Furthermore, an optimal control of procedure system based on the minimization of a quadratic performance index for state vector and control forces is developed. Finally, the effect of dynamic response of the cable, which is produced by viscoelastic parameters, is testified by the research of digital simulation.
文摘舰船动力设备系统产生的持续低频振动会严重影响舰船的声隐身性能及舰船精密设备的工作性能。以自主设计研制的电磁主动吸振器为对象,为了匹配电磁主动吸振器的实际使用工况,在滤波-x最小均方(Filter-x Least Mean Square,FxLMS)控制算法中引入抑制因子,对主动控制力的输出进行限幅。首先通过数值仿真分析验证匹配优化后的控制算法对振动控制的抑制效果,然后介绍基于电磁主动吸振器工程样机搭建的主动控制实验台架系统,以单频激励工况为基础开展主动控制效果验证实验,证明电磁吸振器与匹配优化后的控制算法对低频机械振动控制的有效性。数值仿真和实验结果表明,针对自主设计研制的电磁主动吸振器而提出的匹配优化主动控制算法能够有效抑制低频机械振动响应,在时域和频域均可以取得显著的振动控制效果。
