Study On The Characteristics Of Obstacle Avoidance Sonar In Rhinolophus Ferrumequinum

Bats are the only mammal that have evolved its ability to fly,and it belongs to Chiroptera.Bats' biological sonar system is the result of long-term evolution,and bats use their unique biological sonar system for navigation,positioning,and obstacle avoidance.Bats constantly receive the reflected signals to judge their surroundings and adjust accordingly.This study is the first to analyze the speech signals of Rhinolophus Ferrumequinum during feeding and the relationship between the speech signals and ultrasonic signals.In this paper,the characteristics of FM-CF-FM signal emitted by Rhinolophus Ferrumequinum during obstacle avoidance are analyzed.This thesis mainly includes two parts:(1)Capture Rhinolophus Ferrumequinum at a specific address and bring it back to the lab for feeding in a special bat cage.At the same time,experiments are carried out during the feeding process to study the relationship between their acoustic signals.The first part of the experiment was to record the bread worm from the head of the bat to be tested from far to near,and record the changes in the ultrasonic signal emitted by the genus.In the second part of the experiment,the acoustic signals emitted by the bats to be tested during the eating process were recorded,and the detected spectrograms were analyzed to study the relationship between the speech signals and the ultrasonic signals.(2)Study on the characteristics of the scorpion bat obstacle avoidance.The escaping flight trajectory of the horse daisy head bat obstacle is extracted and the data processing is carried out later,and the two-dimensional flight curve of the obstacle gauge is simulated and its evasive characteristics are determined.The audio data in the process of avoiding the obstacles of the horse bats were analyzed,and the changes of the FM-CF-FM signals emitted by the obstacles were analyzed.The relationship between the ultrasonic signal frequency and the body parameters was analyzed.The findings of the research work are as follows:(1)The Doppler effect is inseparable from the process of using Echolocation tolocate the target and complete the predation.In the process of the distance between the target object and Rhinolophus Ferrumequinum to be tested is far and near,Rhinolophus Ferrumequinum will reduce the frequency of the emitted ultrasonic waves to compensate the Doppler effect,so as to achieve accurate positioning.In this experiment,in the process of bread worms approaching Rhinolophus Ferrumequinum to be tested from far to near,the frequency of the ultrasonic waves emitted by the bats in the four groups of experiments did not find any obvious Doppler effect compensation phenomenon.The speech signal from Rhinolophus Ferrumequinum is multi-harmonic and can clearly distinguish its fundamental and multiple harmonics.The bat's acoustic signal has a wealth of information.In the acoustic signal it emits,the speech signal sometimes appears synchronously with the ultrasonic signal,and sometimes the ultrasonic signal and the speech signal appear separately.(2)Whether there is no obvious relationship between the collision of the copper wire and the horizontal distance of the obstacle avoidance action in the obstacle avoidance experiment,and the vertical distance and the average flight angle are relatively large.The collision probability of the copper wire passing through different diameters increases with the decrease of the diameter.The wavelength of ultrasonic signal obtained by calculation is about 3-5mm.The smaller the obstacle scale is compared with the wavelength of ultrasonic signal,the lower the detection probability and the lower the pass rate.In the experiment,the sound intensity of Rhinolophus Ferrumequinum was positively correlated with the body shape parameters,that is,Rhinolophus Ferrumequinum with large body,long head and long forelimb,and the sound intensity was large.On the contrary,the sound intensity is small.The main frequency of the acoustic signal of the horse buds was not significantly related to the body length,body weight and forelimb length.In this experiment,Rhinolophus Ferrumequinum will emit 6-8 sets of short pulse groups before passing through the copper wire.It has not been found that the number of short pulses in the short pulse group varies significantly with the distance from the copper wire.