CN108001345A - Reversing early warning system and its control method based on STM32 microcontrollers - Google Patents

Abstract

The invention discloses a kind of reversing early warning system and its control method based on STM32 microcontrollers, including gear position sensor, data processing module, apart from display module, ultrasonic distance measuring module, warning module, emergency braking module, vehicle speed sensor, temperature-measuring module and power module, gear position sensor is installed on automobile gears executor, ultrasonic distance measuring module is mounted obliquely on automobile tail, temperature-measuring module is installed on automobile external, gear position sensor is connected with data processing module, vehicle speed sensor is connected with data processing module, data processing module respectively with apart from display module, ultrasonic distance measuring module, warning module, emergency braking module, temperature-measuring module is connected with power module；The present invention can accomplish the presence of the detection chase that reversing early warning system cannot accomplish at present, can calculate and show real-time range of the automobile in reversing process between chase, have certain forewarning function to driver.

Description

Reversing warning system and its control method based on STM32 microcontroller

technical field

The invention relates to a backing warning system, in particular to a backing warning system based on an STM32 single-chip microcomputer and a control method thereof.

Background technique

While automobiles bring convenience to human beings, they also bring potential safety hazards to human life. Traffic accidents occur from time to time, causing many people to lose their precious lives. Many accidents are caused by the driver's negligence and failure to brake in time. In addition, changes in road conditions, weather conditions, and driver misuse are also one of the reasons for traffic accidents. Road traffic accidents have brought huge losses to the country, collectives and families. Therefore, the development and improvement of automobile safety technology needs to be solved urgently.

In the prior art, there is an automatic braking system, which is often used for early warning braking when the car is reversing. Generally, it is used to detect obstacles behind the car so as to effectively brake the car. However, a series of traffic accidents may occur if the existence of the groove is not detected when the car is reversing. Therefore, there is an urgent need for a reversing warning system and its control system that can detect the groove and brake in time. method.

Contents of the invention

The technical problem to be solved by this invention is to provide a kind of reversing warning system based on STM32 single-chip microcomputer and its control method for the above-mentioned deficiencies in the prior art. It is impossible to detect the existence of the groove, and it can calculate and display the real-time distance between the car and the groove during the reversing process, so that the driver can have a more accurate understanding of the position of the groove when reversing.

For realizing above-mentioned technical purpose, the technical scheme that the present invention takes is:

A kind of reversing early warning system based on STM32 single-chip microcomputer, comprises gear position sensor, data processing module, distance display module, ultrasonic ranging module, early warning module, emergency brake module, vehicle speed sensor, temperature measurement module and power supply module, described gear position The sensor is installed on the car gear manipulator, the data processing module and the power supply module are installed in the trunk of the car, and the distance display module, early warning module, vehicle speed sensor and emergency braking module are all installed in the cab of the car. The ultrasonic ranging module is installed obliquely at the rear of the car, the temperature measuring module is installed outside the car, the gear position sensor is connected to the data processing module, the vehicle speed sensor is connected to the data processing module, and the data processing module The modules are respectively connected with the distance display module, ultrasonic distance measurement module, early warning module, emergency braking module, temperature measurement module and power supply module;

Described data processing module comprises STM32 single-chip microcomputer, crystal oscillator circuit and reset circuit, and described ultrasonic ranging module comprises ultrasonic transmitter, ultrasonic receiver, filter circuit, amplifying circuit and shaping circuit, and described crystal oscillator circuit and reset circuit and described STM32 The single-chip microcomputer is connected, the STM32 single-chip microcomputer is connected with the ultrasonic transmitter, the ultrasonic receiver is connected with the filter circuit, the filter circuit is connected with the amplifying circuit, the amplifying circuit is connected with the shaping circuit, and the shaping circuit is connected with the STM32 microcontroller connection.

As a further improved technical solution of the present invention, the temperature measurement module adopts a DS18B20 digital temperature sensor.

As a further improved technical solution of the present invention, the early warning module adopts an audible and visual alarm circuit.

As a further improved technical solution of the present invention, the gear position sensor adopts MLX92232 programmable digital Hall effect sensor.

For realizing above-mentioned technical purpose, another technical scheme that the present invention takes is:

A control method of a reverse warning system based on STM32 single-chip microcomputer, comprising the following steps:

Step 1: The gear sensor monitors the gear of the car in real time and sends a signal to the STM32 microcontroller. The STM32 microcontroller judges whether the gear of the car monitored by the gear sensor is a reverse gear according to the received signal. If so, go to step 2 ;

Step 2: The STM32 MCU sends control signals to the ultrasonic distance measuring module and the temperature measurement module at the same time. The temperature measurement module monitors the ambient temperature and sends the signal to the STM32 MCU. The STM32 MCU processes the received ambient temperature and matches the sound velocity corresponding to the ambient temperature. The STM32 single-chip microcomputer drives the ultrasonic transmitter in the ultrasonic ranging module to emit ultrasonic waves obliquely downward. The ultrasonic signal propagates in the air and is reflected after encountering the ground. Wave, and then through the filter circuit, amplifier circuit and shaping circuit to enter the external interrupt port of the STM32 MCU to generate an interrupt, the STM32 MCU stops timing, and the STM32 MCU calculates the distance between the car and the ground according to the sound velocity corresponding to the ambient temperature and the timing time Distance, the distance display module displays the distance between the car and the ground in real time according to the STM32 microcontroller control command;

Step 3: The STM32 microcontroller judges the calculated distance. If the calculated distance changes suddenly and the distance value of the sudden change exceeds the preset sudden change threshold, the STM32 microcontroller judges that the ground behind the rear of the car is a groove, and executes Step 4: If the calculated distance continues to increase, then the STM32 single-chip microcomputer judges that the ground behind the rear of the car is a descending gentle slope, and the early warning module reports to the police according to the STM32 single-chip microcomputer control command, and ends;

Step 4: When the STM32 MCU judges that the back of the car is a concave ditch, the early warning module will alarm according to the STM32 MCU control command. At the same time, the STM32 MCU controls the vehicle speed sensor to start working. Calculate the real-time distance between the rear of the car and the groove;

Step 5: When the real-time distance between the rear of the car and the groove calculated by the STM32 microcontroller is less than the preset distance threshold range, the STM32 microcontroller controls the emergency braking module, which brakes the car.

As a further improved technical solution of the present invention, the real-time distance between the rear of the car and the concave groove is calculated according to the vehicle speed information detected by the vehicle speed sensor by the STM32 single-chip microcomputer:

(1) STM32 MCU calculates the horizontal distance between the groove and the rear of the car:

S=D*sin(A);

Among them, S is the horizontal distance between the groove calculated by the STM32 microcontroller and the rear of the car, D is the distance between the car and the ground measured by the ultrasonic ranging module before detecting the groove, and A is the distance emitted by the ultrasonic ranging module. The angle between the ultrasonic wave and the vertical downward direction;

(2) According to the vehicle speed detected by the vehicle speed sensor in real time, the distance traveled by the vehicle when reversing is calculated;

(3) The horizontal distance between the groove and the rear of the car calculated by the STM32 microcontroller minus the distance traveled by the car when reversing is equal to the real-time distance between the rear of the car and the groove.

The beneficial effects of the present invention are as follows: the present invention proposes an improvement to the reversing warning system based on the STM32 single-chip microcomputer, which can detect the existence of grooves that cannot be achieved by the current reversing warning system, and can calculate and show that the car is in the process of reversing The real-time distance between the center and the groove allows the driver to have a more accurate understanding of the position of the groove when reversing. And it can be realized that when the driver knows the existence of the concave groove and cannot perform artificial braking in time due to subjective reasons, emergency braking measures can be taken.

Description of drawings

Fig. 1 is a schematic diagram of the circuit principle of the present invention.

Fig. 2 is a schematic structural diagram of the ultrasonic waves emitted by the ultrasonic ranging module before the groove is detected in the present invention.

Fig. 3 is a schematic structural diagram of the ultrasonic waves emitted by the ultrasonic ranging module when the present invention detects a groove.

Fig. 4 is a schematic structural diagram of the ultrasonic waves emitted by the ultrasonic ranging module before the detection of the descending gentle slope according to the present invention.

Fig. 5 is a schematic structural diagram of the ultrasonic waves emitted by the ultrasonic distance measuring module when the present invention detects a gentle descending slope.

Fig. 6 is a working flowchart of the present invention.

Detailed ways

Below according to Fig. 1 to Fig. 6, the specific embodiment of the present invention is further described:

Referring to Figure 1, a reversing warning system based on STM32 single-chip microcomputer, including a gear sensor, a data processing module, a distance display module, an ultrasonic ranging module 4, an early warning module, an emergency braking module, a vehicle speed sensor, a temperature measurement module and a power supply module , the gear sensor is installed on the gear manipulator of the car 1, the data processing module and the power supply module are installed in the trunk of the car 1, the distance display module, early warning module, vehicle speed sensor and emergency braking module All are installed in the cab of the automobile 1, and the ultrasonic ranging module 4 is installed obliquely at the rear of the automobile 1, so that the installation angle of the transmitting probe in the ultrasonic ranging module 4 is A, so that the ultrasonic ranging module 4 can be launched to the ground The angle between the ultrasonic wave 2 of 3 and the vertical downward direction is A, as shown in Figure 2, the temperature measurement module is installed on the outside of the car 1, mainly detects the ambient temperature outside the car 1, the gear sensor and the The data processing module is connected, the gear sensor is used to send the vehicle 1 gear information to the data processing module, the vehicle speed sensor is connected to the data processing module, the vehicle speed sensor is used to send the reverse speed to the data processing module, and the data processing Module is connected with distance display module, ultrasonic ranging module 4, early warning module, emergency brake module, temperature measurement module and power supply module respectively; Described data processing module comprises STM32 single-chip microcomputer, crystal oscillator circuit and reset circuit, described ultrasonic ranging module 4 includes an ultrasonic transmitter, an ultrasonic receiver, a filter circuit, an amplifying circuit and a shaping circuit, the crystal oscillator circuit and the reset circuit are connected to the STM32 single-chip microcomputer, the STM32 single-chip microcomputer is connected to the ultrasonic transmitter, and the ultrasonic receiver is connected to the Described filtering circuit is connected, and described filtering circuit is connected with amplifying circuit, and described amplifying circuit is connected with shaping circuit, and described shaping circuit is connected with described STM32 one-chip computer.

In this embodiment, the temperature measurement module uses a DS18B20 digital temperature sensor.

In this embodiment, the early warning module adopts an audible and visual alarm circuit.

In this embodiment, the gear position sensor adopts MLX92232 programmable digital Hall effect sensor. The vehicle speed sensor adopts a Hall type vehicle speed sensor.

The present invention also provides a control method for the reverse warning system based on the STM32 single-chip microcomputer. Starting with the car 1 in the reverse gear, the ultrasonic ranging module 4 and the temperature measurement module work synchronously, and the measured data are transmitted to the STM32 single-chip microcomputer for development. The board is processed, and the STM32 single-chip microcomputer compares and analyzes the processed data with the preset data, and obtains the work to be carried out in the next step. If it meets the pre-set range value, it will perform early warning and emergency braking.

Referring to Figure 6, it specifically includes the following steps:

Step 1: The gear position sensor (using MLX92232 programmable digital Hall effect sensor, which has high reliability, small package, provides various output options and is easy to implement) monitors the gear position of the car 1 in real time and sends a signal to the STM32 microcontroller, STM32 Whether the single-chip microcomputer judges whether the gear position of the automobile 1, which the gear position sensor monitors, is a reverse gear position according to the received signal, if so, then perform step 2;

Step 2: The STM32 MCU sends control signals to the ultrasonic distance measuring module 4 and the temperature measurement module at the same time (the ultrasonic distance measurement module 4 and the temperature measurement module work synchronously, and the temperature measurement module uses a temperature sensor), the temperature measurement module monitors the ambient temperature and sends signals to STM32 single-chip microcomputer, STM32 single-chip microcomputer processes the received ambient temperature and matches the sound velocity corresponding to the ambient temperature to ensure the accuracy of measurement; the STM32 single-chip microcomputer drives the ultrasonic transmitter in the ultrasonic ranging module 4 to emit ultrasonic waves 2 obliquely downward, and the ultrasonic signals are It propagates in the air and reflects when it encounters the ground 3. The STM32 single-chip microcomputer starts timing at the same time as the ultrasonic wave 2 is emitted. The external interrupt port generates an interrupt, the STM32 single-chip microcomputer stops timing, and the STM32 single-chip microcomputer calculates the distance between the car 1 and the ground 3 reflected by the ultrasonic wave 2 according to the sound velocity corresponding to the ambient temperature and the timing time, and the distance display module displays it in real time according to the STM32 single-chip microcomputer control command The distance between the car 1 and the ground 3 reflected by the ultrasonic wave 2;

Step 3: The STM32 microcontroller judges the calculated distance, if the calculated distance changes suddenly and the distance value of the sudden change exceeds the preset sudden change threshold (in this embodiment, the preset sudden change threshold is set to 20 CM) , then the STM32 single-chip microcomputer judges that the ground 3 behind the rear of the car 1 is a groove 5, as shown in Figures 2 and 3, and executes step 4; if the calculated distance continues to increase, and the range of continuous increase is less than or equal to 20 CM, then The STM32 microcontroller judges that the ground 3 behind the rear of the car 1 is a gentle slope 6, as shown in Figures 4 and 5. The early warning module issues an alarm according to the STM32 microcontroller control command. The early warning module uses LED light alarm and buzzer sound alarm, LED (can be set Green light) and the buzzer flash and sound intermittently, and the LED and buzzer can also adjust the corresponding frequency according to the remaining distance, end;

Step 4: When the STM32 single-chip computer judges that there is a groove 5 behind the car 1, the early warning module will give an alarm according to the control command of the STM32 single-chip computer. Judging the car by observing the color of the LED lights of the early warning module in the cab 1) and the buzzer flashes and sounds intermittently, and at the same time the STM32 MCU controls the speed sensor to start working, the STM32 MCU receives the signal from the speed sensor, and the STM32 MCU according to the speed sensor The detected vehicle speed information calculates the real-time distance between the tail of the automobile 1 and the groove 5;

Step 5: When the real-time distance between the tail of the car 1 and the groove 5 calculated by the STM32 microcontroller is within the preset distance threshold range (in this embodiment, the preset distance threshold range is set to be less than or equal to 100CM and greater than 50CM) , the brightness of the LED red light in the early warning module reaches the highest, the volume of the buzzer reaches the maximum and continues to whistle to warn the driver that if the car continues to reverse, it will reverse into the ditch. When the real-time distance is less than the preset distance threshold range (less than or equal to 50CM), the STM32 single-chip microcomputer controls the emergency braking module, and the emergency braking module brakes the car 1 .

In the present embodiment, referring to Fig. 2 and Fig. 3, described STM32 single-chip microcomputer calculates the real-time distance between automobile 1 rear end and groove 5 according to the vehicle speed information that vehicle speed sensor detects and comprises:

(1) The STM32 microcontroller calculates the horizontal distance between the groove 5 and the rear of the car 1:

S=D*sin(A);

Where S is the horizontal distance between the groove 5 calculated by the STM32 microcontroller and the rear of the car 1, and D is the distance between the car 1 and the ground 3 reflected by the ultrasonic wave 2 measured by the ultrasonic ranging module 4 before detecting the groove 5, A is the angle between the ultrasonic wave 2 emitted by the ultrasonic ranging module 4 and the vertical downward direction;

(2) Calculate the distance traveled by the car 1 when reversing according to the speed of the car 1 detected in real time by the speed sensor;

(3) The horizontal distance between the groove 5 and the tail of the car 1 calculated by the STM32 microcontroller minus the distance traveled by the car 1 when reversing is equal to the real-time distance between the tail of the car 1 and the groove 5 .

In this embodiment, when the car 1 is reversing and encounters a groove 5 with an angle of about 90°, the distance D1 measured by the ultrasonic wave 2 will undergo a sudden change. In this design, the sudden change distance △D= When D2-D1>20CM, it is considered as concave groove 5 (when the angle A is 30 degrees, it can be obtained by the Pythagorean theorem that H>10CM at this time), the reason why △D and H are set so small is because Safety considerations, when the set value is smaller, the autonomous safety of car 1 is higher.

As shown in Figure 4 to Figure 5, when the car 1 is continuously reversing and encounters a gentle slope, it can be seen that the distance measured by the ultrasonic wave 2 is gradually increasing. In this case, there is still a certain risk of blind reversing, so the existence of the gentle slope is detected and Early warning is very necessary.

The present invention proposes an improvement to the reversing warning system based on the STM32 single-chip microcomputer. It can detect the existence of the groove 5, which cannot be done by the current reverse warning system, and can calculate and display the real-time distance between the car 1 and the groove 5 during the reversing process, so that the driver can check the groove 5 when reversing. The location has a more precise cognition. And it can be realized that when the driver knows the existence of the concave groove 5 and cannot perform artificial braking in time due to subjective reasons, emergency braking measures can be taken.

The scope of protection of the present invention includes but is not limited to the above embodiments. The scope of protection of the present invention is based on the claims. Any replacement, deformation, and improvement that are easily conceived by those skilled in the art for this technology fall within the scope of the present invention. protected range.

Claims (6)

1. A reversing warning system based on STM32 single-chip microcomputer, it is characterized in that: comprise gear position sensor, data processing module, distance display module, ultrasonic ranging module, early warning module, emergency braking module, vehicle speed sensor, temperature measurement module and power supply module, the gear position sensor is installed on the car gear manipulator, the data processing module and power supply module are installed in the trunk of the car, and the distance display module, early warning module, vehicle speed sensor and emergency braking module are all installed in the In the cab of a car, the ultrasonic distance measuring module is installed obliquely at the rear of the car, the temperature measuring module is installed outside the car, the gear position sensor is connected to the data processing module, and the vehicle speed sensor is connected to the data processing module connected, the data processing module is respectively connected with the distance display module, the ultrasonic ranging module, the early warning module, the emergency braking module, the temperature measurement module and the power supply module; Described data processing module comprises STM32 single-chip microcomputer, crystal oscillator circuit and reset circuit, and described ultrasonic ranging module comprises ultrasonic transmitter, ultrasonic receiver, filter circuit, amplifying circuit and shaping circuit, and described crystal oscillator circuit and reset circuit and described STM32 The single-chip microcomputer is connected, the STM32 single-chip microcomputer is connected with the ultrasonic transmitter, the ultrasonic receiver is connected with the filter circuit, the filter circuit is connected with the amplifying circuit, the amplifying circuit is connected with the shaping circuit, and the shaping circuit is connected with the STM32 microcontroller connection. 2. the reversing warning system based on STM32 single-chip microcomputer according to claim 1, is characterized in that: described temperature measurement module adopts DS18B20 digital temperature sensor. 3. The reversing warning system based on STM32 single-chip microcomputer according to claim 1, characterized in that: said warning module adopts sound and light alarm circuit. 4. The reversing warning system based on STM32 single-chip microcomputer according to claim 1, characterized in that: the gear position sensor adopts MLX92232 programmable digital Hall effect sensor. 5. a kind of control method based on the reversing warning system of STM32 single-chip microcomputer as claimed in claim 1, it is characterized in that: comprise the following steps: Step 1: The gear sensor monitors the gear of the car in real time and sends a signal to the STM32 microcontroller. The STM32 microcontroller judges whether the gear of the car monitored by the gear sensor is a reverse gear according to the received signal. If so, go to step 2 ; Step 2: The STM32 MCU sends control signals to the ultrasonic distance measuring module and the temperature measurement module at the same time. The temperature measurement module monitors the ambient temperature and sends the signal to the STM32 MCU. The STM32 MCU processes the received ambient temperature and matches the sound velocity corresponding to the ambient temperature. The STM32 single-chip microcomputer drives the ultrasonic transmitter in the ultrasonic ranging module to emit ultrasonic waves obliquely downward. The ultrasonic signal propagates in the air and is reflected after encountering the ground. Wave, and then through the filter circuit, amplifier circuit and shaping circuit to enter the external interrupt port of the STM32 MCU to generate an interrupt, the STM32 MCU stops timing, and the STM32 MCU calculates the distance between the car and the ground according to the sound velocity corresponding to the ambient temperature and the timing time Distance, the distance display module displays the distance between the car and the ground in real time according to the STM32 microcontroller control command; Step 3: The STM32 microcontroller judges the calculated distance. If the calculated distance changes suddenly and the distance value of the sudden change exceeds the preset sudden change threshold, the STM32 microcontroller judges that the ground behind the rear of the car is a groove, and executes Step 4: If the calculated distance continues to increase, then the STM32 single-chip microcomputer judges that the ground behind the rear of the car is a descending gentle slope, and the early warning module reports to the police according to the STM32 single-chip microcomputer control command, and ends; Step 4: When the STM32 MCU judges that the rear of the car is a concave ditch, the early warning module will alarm according to the STM32 MCU control command. At the same time, the STM32 MCU controls the vehicle speed sensor to start working. Calculate the real-time distance between the rear of the car and the groove; Step 5: When the real-time distance between the rear of the car and the groove calculated by the STM32 microcontroller is less than the preset distance threshold range, the STM32 microcontroller controls the emergency braking module, which brakes the car. 6. the control method of the reversing warning system based on STM32 single-chip microcomputer according to claim 5, is characterized in that: described STM32 single-chip microcomputer calculates the real-time distance between the tail end of the car and the concave groove according to the vehicle speed information that vehicle speed sensor detects and comprises: (1) STM32 MCU calculates the horizontal distance between the groove and the rear of the car: S=D*sin(A); Among them, S is the horizontal distance between the groove calculated by the STM32 microcontroller and the rear of the car, D is the distance between the car and the ground measured by the ultrasonic ranging module before detecting the groove, and A is the distance emitted by the ultrasonic ranging module. The angle between the ultrasonic wave and the vertical downward direction; (2) According to the vehicle speed detected by the vehicle speed sensor in real time, the distance traveled by the vehicle when reversing is calculated; (3) The horizontal distance between the groove and the rear of the car calculated by the STM32 microcontroller minus the distance traveled by the car when reversing is equal to the real-time distance between the rear of the car and the groove.