针对无线传感器网络对目标声源的定位问题,依据无线声传感器网络建立了比例向量迭代目标定位算法,每个传感器节点仅配备一个声音传感器作为其感知设备,通过移动向量迭代使得按照接收能量值计算的距离比例和按照估计位置计算的距离不断靠...针对无线传感器网络对目标声源的定位问题,依据无线声传感器网络建立了比例向量迭代目标定位算法,每个传感器节点仅配备一个声音传感器作为其感知设备,通过移动向量迭代使得按照接收能量值计算的距离比例和按照估计位置计算的距离不断靠近,从而使估计位置逐渐逼近目标真实位置,初始估计位置通过加权质心法获得。根据比例向量迭代算法确定了4节点模型的节点选择方法,并仿真分析了算法的定位过程和定位精度。结果表明,比例向量迭代定位算法能够利用至少3个节点对目标声源进行定位,且平均定位精度为-15 d B,满足无线声传感器网络对目标的定位要求。展开更多
Calculating the flow coefficient of a spool-valve is complicated due to the coupling–throttling effect in the throttling grooves of a proportional–directional valve.In this paper,a methodology for expressing the flo...Calculating the flow coefficient of a spool-valve is complicated due to the coupling–throttling effect in the throttling grooves of a proportional–directional valve.In this paper,a methodology for expressing the flow coefficient of coupled throttling grooves is proposed to resolve that difficulty.With this purpose,an approach of a 3 D numerical simulation and an experimental bench were introduced based on the prototype of a commercial proportional valve.The results show consistency between the numerical simulation and the bench test.Based on that,the concept of‘saturation limit’is introduced to describe the value gap between the current and saturated flows,so that the flow-coefficient saturation limit of the prototype in the process can be deducted.Accordingly,an approximate flow coefficient suitable for coupled throttling grooves within finite variable space,which is based on three typical throttling structures(i.e.O-shape,U-shape,and C-shape)of the coupled throttling grooves,is obtained based on an orthogonal test.The model results are consistent with the numerical and experimental results,with maximum errors of less than 5.29%and 5.34%,respectively.This suggests that the proposed method is effective in approximating the flow coefficient.展开更多
文摘针对无线传感器网络对目标声源的定位问题,依据无线声传感器网络建立了比例向量迭代目标定位算法,每个传感器节点仅配备一个声音传感器作为其感知设备,通过移动向量迭代使得按照接收能量值计算的距离比例和按照估计位置计算的距离不断靠近,从而使估计位置逐渐逼近目标真实位置,初始估计位置通过加权质心法获得。根据比例向量迭代算法确定了4节点模型的节点选择方法,并仿真分析了算法的定位过程和定位精度。结果表明,比例向量迭代定位算法能够利用至少3个节点对目标声源进行定位,且平均定位精度为-15 d B,满足无线声传感器网络对目标的定位要求。
基金Project supported by the National Key R&D Program of China(No.2018YFC0810203)。
文摘Calculating the flow coefficient of a spool-valve is complicated due to the coupling–throttling effect in the throttling grooves of a proportional–directional valve.In this paper,a methodology for expressing the flow coefficient of coupled throttling grooves is proposed to resolve that difficulty.With this purpose,an approach of a 3 D numerical simulation and an experimental bench were introduced based on the prototype of a commercial proportional valve.The results show consistency between the numerical simulation and the bench test.Based on that,the concept of‘saturation limit’is introduced to describe the value gap between the current and saturated flows,so that the flow-coefficient saturation limit of the prototype in the process can be deducted.Accordingly,an approximate flow coefficient suitable for coupled throttling grooves within finite variable space,which is based on three typical throttling structures(i.e.O-shape,U-shape,and C-shape)of the coupled throttling grooves,is obtained based on an orthogonal test.The model results are consistent with the numerical and experimental results,with maximum errors of less than 5.29%and 5.34%,respectively.This suggests that the proposed method is effective in approximating the flow coefficient.
