Design On The Inner Wheel Blind Spot Detection System Based On Millimeter Wave Radar

Safety,environmental protection and energy saving are the three major themes of automotive technology development.With the rapid development of smart cars,how to ensure the safety of cars in a more intelligent and effective way has become the key to the development of modern cars.Inner wheel difference is a dangerous area that cannot be eliminated when the vehicle turns,especially for large vehicles,the impact is greater,,and more prone to traffic safety accidents.In this paper,a blind area monitoring system of inner wheel difference based on millimeter wave radar is designed.The specific research contents are as follows:1)inside the wheel traditional calculation mathematical model,and on this basis,the establishment of a more accord with the actual driving conditions within the wheel model,obtained the rear wheel track and the minimum turning radius,wheelbase and the relationship between the speed,the rear wheel curve fitting equation was established,and calculation of the wheel in the poor area,analyzed the reasons of influence within the wheel area size.The dead Angle of the field of vision in the process of driving is calculated and its variation law is explored.The results show that the larger the wheelbase is,the larger the difference area of the inner wheel is,and the dead Angle of the field of vision is the "big-small-big" variation law,and the maximum value is 22.39°.2)automotive safety brake model and calculate the braking safety distance of 25.5 m,sensor detection range is much greater than 25.5 m,on the basis of millimeter wave radar is chosen as the blind spot monitoring sensor,identified 77 GHZ as working band of millimeter wave radar,design and arrangement of the sensor combination scheme,each hardware module determines the required by the system,the system works,this paper introduces the principle of blind spot monitoring,millimeter wave radar to static and dynamic target range and speed measuring principle.The calculation formulas of target frequency,velocity and distance are obtained.3)has carried on the overall design to the signal processing hardware circuit;the signal processing requirements were analyzed,and the surround:ing STM32F103 core chip,gives a system hardware solution,the design includes filtering amplifying circuit,the adjustable gain amplification circuit,dc bias circuit,signal processing circuit,using the multisim simulation platform for the joint simulation signal processing performance,and has carried on the system of the micro controller module,power module,CAN communication module,a buzzer module PCB design.4)designed the signal algorithm based on the library function programming of C language,designed the 100hz triangular wave modulation signal algorithm,observed the output curve with oscilloscope,designed the AD sampling algorithm,and uploaded the sampling results to the computer through the serial port to observe the sampling characteristics.The fdatool toolbox in matlab is used to design digital.filter,and the bandpass filter coefficient is obtained.The difference frequency is calculated by using the base 4-fft algorithm of 1024 points for the digitally filtered signal.The system warning algorithm is designed,the distance and speed of the target are calculated,and the logic judgment is m ade.5)Experimental verification of the blind spot monitoring system was carried out,site simulation detection experiments were carried out on static targets and lateral dynamic targets,and the experimental data was recorded.After calculation,the static target ranging error and azimuth error were about 5%and 6%,respectively.The maximum speed detection error is 7.8%,which meets the application requirements.