小型无人机振动特性对超声波传感器的影响

【目的】安全避障是目前无人机(Unmanned aerial vehicle,UAV)领域迫切需要解决的一个难题,利用超声波传感器是无人机避障的重要手段之一,针对无人机飞行过程中机械振动的特性以及对超声波测距传感器的影响进行了研究,以提高超声波测距传感器的精准度,改善无人机作业稳定性。【方法】通过采集无人机不同油门开度的振动数据,进行多信号分析,得到无人机振动强度的空间和频域分布,并根据振动强度的空间分布,测定无人机振动对于超声波测距传感器的误差影响。【结果】随着离无人机中心距离的增加,无人机机臂上振动强度的空间分布存在减弱和加强交替出现的现象,离无人机中心最远处出现最大振动强度;振动幅度随着频率的增加而降低;无人机在载桨运行过程中对于机载超声波测距传感器水平测距影响最大,最大误差达到0.69 m,垂直方向的误差最大为0.20 m。【结论】随着离无人机中心距离和油门的增大,振动强度增大;调整传感器的振动频率可以减少无人机振动对传感器的影响。本研究结果为超声波传感器在农业无人机安全避障方面的应用提供了参考。

Impacts of small-size unmanned aerial vehicle vibration characteristics on ultrasonic transducers

Objective]Obstacle avoidance is a crucial issue in unmanned aerial vehicle( UAV) operation. Ultrasonic transducers are critical components in UAV obstacles avoidance system.The vibration charac-teristics of UAV are important to increase UAV obstacles avoidance capability.Research was conducted to understand the vibration characteristics of small-size UAV( SUAV) and impacts of vibration on ultra-sonic sensors.Method]Spatial distributions of SUAV vibration strength and the distributions in frequen-cy domain were derived by acquiring SUAV vibration data at multiple test points with different throttles. The impact of SUAV vibration characteristic on ultrasonic transducer performance was detected through the spatial distribution of vibration strength.Result]With the distance away from the center and along the arms of SUAV, the increase and decrease of vibration strength occurred alternatively.Equipped with propellers , the ultrasonic transducer had a max error of 0 .69 m in horizontal direction while the maximum error only reached 0.20 m in vertical direction.Conclusion]With the distance away from center and throttles increasing, the amplitude of vibration is strengthened.To avoid the effect of vibration, it is nec-essary to adjust the vibrational frequency of sensor.Findings reported in this paper may provide guidance for applications of ultrasonic transducer in agricultural SUAVs.