增强型超声波周向旋转扫描节点参数优化

Parameter optimization of enhanced ultrasonic circumferential scanning node in WSN

无线传感器网络(WSN)节点具有的全向感知能力决定了网络覆盖性能,故先对增强型超声波传感器的尺寸和外形进行了优化仿真。仿真结果表明:优化后的号筒对超声波发射声场的指向性提升较为明显,在中心轴线上辐射的声压比普通传感器大3.5倍。然后利用增强型超声波传感器设计了单发单收超声波旋转扫描系统,建立了针对超声波测距的最高扫描转速模型,确定了扫描转速与超声波脉冲频率的匹配关系,并分析了该系统的目标捕获率。计算结果表明:超声波旋转扫描系统在具有较好匹配度的情况下,最高转速为215r/min,可捕获速度低于64.5km/h的目标。

Directional Sensor Network（DSN）node with stability of omnidirectional perception plays a decisive role in network coverage.Using the optimization method of SNOPT,the dimensions and shape of enhanced ultrasonic transducer were optimized first.With optimized horn the directivity was promoted obviously and the radiated sound pressure in the central axis was 3.5times bigger than that of normal transducer.Then a new rotational circumferential scanning program of single-beam was designed based on the enhanced ultrasonic transducer.The model of the highest scanning speed for ultrasonic ranging was built,and the highest scanning speed of 253r/min was achieved for monitoring the target in 6 m away.In order to get stabilized prospecting effect,the matching relationship between scanning speed and pulse frequency was established for constant number of ultrasonic beams in one scanning period.At last,target acquisition rate was analyzed.Calculation results demonstrate that the highest speed of the ultrasonic circumferential scanning system is 215r/min in the case of good compatibility,which can acquire the target with a speed lower than 65.5km/h.