| Cars are usually equipped with reversing images,some vehicles have bad working conditions,so the use of reversing images is not realistic.Even if there is a reverse image,because the image lens generally adopts wide-angle design,the picture will be distorted.For those who lack sense of distance,it is still difficult to turn back safely,so it is necessary to install an ultrasonic reversing radar.At present,the reversing radar on the market can only detect the obstacles in a certain height in the rear,but for large vehicles such as large trucks,the blind area is very large.It is necessary to design a reverse alarm system suitable for large vehicles and other large vehicles.In this context,this paper first introduces some basic characteristics of ultrasonic wave and the commonly used ultrasonic distance measuring scheme.Finally,it designs an ultrasonic reversing auxiliary alarm system based on practical means and actual needs.This system can not only detect obstacles behind the rear part of the car,but also provide a good indication for large obstacles on both sides of the car body.In this paper,by analyzing the basic principle of ultrasonic distance measurement and combining the desired purpose,the ultrasonic transmitting and receiving circuit,display circuit,alarm circuit and so on are designed.In order to improve accuracy in ranging,temperature compensation is also adopted.Finally,through the simulation test,it is found that the system can not only realize the distance of the horizontal positive direction 20cm-400 cm more accurately,when there are obstacles in the rear,it can alarm in time and can determine the general orientation of the object.It also has a certain wake effect on the large obstacles on both sides of the car body.This design has the advantages of low cost and high integration.It has a good effect on the reversing of the auxiliary low end car and the large truck driver,so it still has a certain theoretical and practical value. |
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