CN104002676A - Automobile accelerator wrong-pressing judgment method based on DSP2812 controller - Google Patents

Abstract

The invention discloses a DSP2812 controller-based judging method for wrongly stepping on the accelerator of an automobile. This method can quickly and accurately judge the real intention of the driver to quickly step on the accelerator through two judgment conditions, that is, the pedal acceleration and the information of the obstacle in front of the vehicle, plus the relationship with the real-time vehicle speed; Control and control the braking process of the car precisely, so that the reliability and response speed of the whole system are higher; the control part of the system has a simple structure, fast response speed, and the control method is fast and effective. To achieve the purpose of preventing accidental stepping on the accelerator.

Description

A Judgment Method of Vehicle Accelerator Misstepping Based on DSP2812 Controller

technical field

The invention relates to the field of automobile safety protection, in particular to a method for judging wrongly stepping on the accelerator of an automobile based on a DSP2812 controller. the

Background technique

At present, with the continuous improvement of people's living standards and the rapid growth of car ownership, more and more people choose to travel by car, and accordingly, traffic accidents also increase. According to reports from NISSAN Corporation, about 7,000 accidents are caused by mistakenly stepping on the accelerator pedal as a brake pedal in Japan every year. Since the automatic transmission car does not have a clutch pedal, it cannot use the clutch to cut off the power like a manual transmission car. Both the accelerator and the brake pedal are controlled by the right foot, so the driver uses the right foot to step on the accelerator when driving, and needs to lift the right foot when braking. , move towards the brake and depress the pedal to brake the car to slow down. However, in an emergency situation, if there is an obstacle suddenly appearing ahead, the driver is in a state of high tension at this time, especially the first-time driver, it is easy to use the accelerator as a brake in a panic and step on the accelerator hard, causing the vehicle not only will not Stop, but rapidly speed up, resulting in quite serious accidents, not only will cause major economic losses, and even casualties. As a kind of active safety technology of automobiles, anti-acceleration technology can reduce or avoid traffic accidents caused by drivers accidentally stepping on the accelerator when they want to brake suddenly. After research and design, this technology can be widely used in civilian vehicles to improve the personal safety of drivers. the

Contents of the invention

The object of the present invention is to provide a kind of method for judging the wrong stepping on the accelerator of a car based on the DSP2812 controller, which is easy to implement, the system responds quickly, and has high accuracy and reliability; Braking can achieve the purpose of preventing the driver from stepping on the accelerator by mistake. the

The present invention adopts the following technical solutions: a method for judging the wrong step on the accelerator of a car based on a DSP2812 controller, which is characterized in that it includes an acceleration sensor, a radar sensor and a speed sensor, and the acceleration sensor, the radar sensor and the speed sensor are connected with the DSP2812 controller Connection also includes the following steps:

1) Set the accelerator pedal acceleration threshold value at 55-85m/s2;

2) The DSP2812 controller calculates the vehicle distance threshold between the radar sensor and the obstacle according to the sampled value of the real-time speed V of the vehicle measured by the speed sensor;

3) The acceleration sensor collects the acceleration of the accelerator pedal, the radar sensor collects the distance to the obstacle, and then sends it to the DSP2812 controller;

4) The DSP2812 controller performs the following operations:

[1] If the accelerator pedal acceleration a<accelerator pedal acceleration threshold a0, the system does not execute the command;

[2] If the accelerator pedal acceleration a>accelerator pedal acceleration threshold a0 and the distance between the radar sensor and the obstacle L>the distance threshold L0 between the radar sensor and the obstacle, the system does not execute the command, and the driver intends to step on the accelerator quickly;

[3] If the accelerator pedal acceleration a>acceleration pedal acceleration threshold a0 and the distance between the radar sensor and the obstacle L<the distance between the radar sensor and the obstacle threshold L0, the system executes the command, the system judges that the driver stepped on the brake by mistake, and the vehicle Stop fuel supply and apply emergency brakes. the

As an improvement, the radar sensor includes a waveform generating module, a millimeter wave transmitting and receiving module, an antenna and an intermediate frequency preprocessing module, the waveform generating module generates a waveform modulation voltage and outputs it to the millimeter wave transmitting and receiving module, and the millimeter wave transmitting and receiving module The module generates the transmit waveform in the millimeter wave frequency band and radiates it through the antenna. At the same time, the target reflected echo is received through the antenna. After the echo is passed through the millimeter wave transmitting and receiving module, the frequency is down-converted to output the intermediate frequency beat signal. The intermediate frequency preprocessing module automatically performs the intermediate frequency beat signal. Gain control, the output signal is sampled and analyzed by the DSP2812 controller. the

As an improvement, the radar sensor is a millimeter wave radar sensor, the detection angle of the radar sensor is 34-36 degrees, and the minimum detection distance of the radar sensor is 120 meters. the

As an improvement, the vehicle speed V is 0-10km/h, the vehicle distance threshold L is 4.2m, the vehicle speed V is 10-30km/h, the vehicle distance threshold L is 16m, and the vehicle speed V is 30-40km/h. The distance threshold L is 22.9m, the vehicle speed V is 40-50km/h, the vehicle distance threshold L is 31.3m, the vehicle speed V is 50-60km/h, the vehicle distance threshold L is 40.7m, and the vehicle speed V is 60-70km /h, the vehicle distance threshold L is 51.2m, the vehicle speed V is 70-80km/h, the vehicle distance threshold L is 62.8m, the vehicle speed V is 80-90km/h, the vehicle distance threshold L is 75.4m, and the vehicle speed V 90-100km/h, vehicle distance threshold L is 89.1m, vehicle speed V is 100-110km/h, vehicle distance threshold L is 103.9m, vehicle speed V is 110-120km/h, vehicle distance threshold L is 120m . the

As an improvement, the formula for calculating the distance threshold L0 between the radar sensor and the obstacle is

$\mathrm{<span\; class="notranslate">\; S</span>}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>\frac{{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}}{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span>\frac{\mathrm{<span\; class="notranslate">\; \&mu;g</span>}{{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{\mathrm{<span\; class="notranslate">\; twenty\; four</span>}}<span\; class="notranslate">\; +</span>\frac{{{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; \&mu;g</span>}}$

V1: the driving speed of the car before braking;

t1: The reaction time of the driver, the action time of most people in an emergency is about 1 second;

t2: the time from depressing the pedal to generating the braking force, the value is 0.10-0.15s;

After the car generates braking force, the car acceleration a increases linearly, and a ₁ = μg;

$\mathrm{<span\; class="notranslate">\; a</span>}<span\; class="notranslate">\; =</span>\frac{{{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}^{\mathrm{<span\; class="notranslate">\; t</span>}}}{{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; \&mu;gt</span>}}{{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}}$

a1: the maximum value of the vehicle acceleration a;

μ: coefficient of friction between the vehicle and the ground, take μ=0.8;

g: gravity coefficient, take g=9.8m/s ² ;

t3: Vehicle acceleration growth time, the value is 0.15-0.20s. the

Compared with the prior art, the present invention precisely controls the braking process of the automobile through DSP control during emergency braking; the reliability and response speed of the whole system are higher; the present invention adopts DSP as the signal processing controller, and the acceleration Sensors and radar sensors are directly connected to DSP; compared with single-chip microcomputers, DSP has higher integration and faster CPU, so the response speed and reliability of this system are also higher. At the same time, the power consumption of DSP is very low, which saves energy. DSP has more bus structures, powerful external communication interfaces (SCI, SPI, CAN) to facilitate the formation of large control systems, higher operating speed and flexibility, pipeline operation mode and faster CPU make the data processing capacity of the system And the response speed is higher; the system can quickly and accurately judge the real intention of the driver to step on the accelerator quickly and accurately through two judgment conditions, namely the pedal acceleration and the obstacle information in front of the vehicle, plus the relationship with the real-time vehicle speed. The control part of the system has a simple structure, fast response, and the control method is fast and effective. It not only cuts off the oil circuit to stop the car from accelerating, but also brakes in an emergency to prevent accidental stepping on the accelerator. the

Description of drawings

Figure 1 is a schematic diagram of the structure realized by this method. the

Figure 2 is a schematic diagram of the implementation of this method. the

Fig. 3 is a schematic diagram of the braking distance of the method. the

Detailed ways

Specific embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings. the

As shown in Fig. 1, Fig. 2 and Fig. 3, the following steps are included: a kind of specific implementation of the method for judging wrong stepping on the automobile accelerator based on DSP2812 controller, including acceleration sensor 1, radar sensor 2 and speed measuring sensor 3, so The acceleration sensor 1, the radar sensor 2 and the speed sensor 3 are connected with the DSP2812 controller 4, and the following steps are also included:

1) Set the accelerator pedal acceleration threshold a0 at a value of 55-85m/s2;

2) The DSP2812 controller 4 calculates the vehicle distance threshold L0 between the radar sensor 2 and the obstacle according to the real-time speed V sampling value of the vehicle measured by the speed sensor 3;

3) The acceleration sensor 1 collects the accelerator pedal acceleration a, and the radar sensor 2 collects the distance L from the obstacle, and then sends it to the DSP2812 controller 4;

4) DSP2812 controller 4 performs the following operations:

[1] If the accelerator pedal acceleration a<accelerator pedal acceleration threshold a0, the system does not execute the command;

[2] If the accelerator pedal acceleration a>accelerator pedal acceleration threshold a0 and the distance between radar sensor 2 and the obstacle L>the distance threshold L0 between the radar sensor and the obstacle, the system does not execute the command, and the driver intends to step on the accelerator quickly ;

[3] If the accelerator pedal acceleration a>acceleration pedal acceleration threshold a0 and the distance between the radar sensor and the obstacle L<the distance between the radar sensor and the obstacle threshold L0, the system executes the command, the system judges that the driver stepped on the brake by mistake, and the vehicle Stop fuel supply and apply emergency brakes. the

After the above method is adopted, the system judges that the accelerator pedal is accidentally stepped on and can respond quickly, so that the engine is turned into an idle state to achieve the purpose of reducing the speed of the vehicle, and at the same time, the brake is activated, which overcomes the shortcomings of the judgment system of mistakenly stepping on the accelerator pedal in the prior art: one is The device is developed according to mechanical principles, and the judgment conditions are single. It is impossible to accurately judge the real purpose of the driver's stepping on the accelerator, and because the individual's physical fitness is different, the force of stepping on the pedal is also different, so the reliability and practicability of the system are not high; one is Based on the electronic control device of the single-chip microcomputer, for example, when the driver steps on the accelerator, if the pedal stepping voltage signal collected by the single-chip microcomputer exceeds the reference value, the braking function will be executed and maintained for 2s, and the judgment conditions are relatively simple, and the accuracy and reliability are not high. And the key technology is still immature. The acceleration range is 5-40m/s2 in normal or when the accelerator is stepped on. In order to ensure that the system will not accidentally cause the car to brake suddenly due to normal or overtaking accelerator pedal, the acceleration threshold a0 should be greater than 40m/s2. The acceleration range is 100-140m/s2. In order to ensure the reliability of the system, the acceleration threshold a0 should be less than 100m/s2. Therefore, the value of a0 should be 55-85m/s2. , the conditions under which the system operates when the accelerator is accidentally stepped on in an emergency. At the same time, according to the real-time value of the vehicle speed and the vehicle distance threshold L selected and set, the speed is fast, the amount of calculation is small, the implementation is simple, and the effect is good. the

As an improved specific implementation, the radar sensor 2 includes a waveform generating module, a millimeter wave transmitting and receiving module, an antenna and an intermediate frequency preprocessing module, the waveform generating module generates a waveform modulation voltage and outputs it to the millimeter wave transmitting and receiving module, The millimeter-wave transmitting and receiving module generates the transmitting waveform in the millimeter-wave frequency band and radiates it through the antenna. At the same time, the antenna receives the reflected echo of the target. Automatic gain control is performed on the beat signal, and the output signal is sampled and analyzed by the DSP2812 controller 4 . Millimeter-wave radar can actively obtain information such as distance and speed from obstacles in front. It has the advantages of small size, light weight, high resolution in both azimuth and distance, and has a strong ability to penetrate fog, smoke, and dust. , has the characteristics of all-weather and all-day time. In addition, the anti-jamming and anti-stealth capabilities of millimeter-wave radar are also superior to other microwave radars. In the past two decades, millimeter-wave radar has been widely developed and applied, especially in the fields of meteorology, traffic control, and vehicle collision avoidance. the

As an improved specific implementation, the radar sensor 2 is a millimeter wave radar sensor, the detection angle of the radar sensor 2 is 34-36 degrees, and the minimum detection distance of the radar sensor 2 is 120 meters. The angle is calculated, and the detection range of the radar can cover a vehicle with a width of 2m at a distance of at least 3m from obstacles. Most of the emergencies that occur during driving can be prevented. the

As an improved specific implementation, the vehicle speed V is 0-10km/h, the vehicle distance threshold L is 4.2m, the vehicle speed V is 10-30km/h, the vehicle distance threshold L is 16m, and the vehicle speed V is 30-40km /h, the vehicle distance threshold L is 22.9m, the vehicle speed V is 40-50km/h, the vehicle distance threshold L is 31.3m, the vehicle speed V is 50-60km/h, the vehicle distance threshold L is 40.7m, and the vehicle speed V 60-70km/h, vehicle distance threshold L is 51.2m, vehicle speed V is 70-80km/h, vehicle distance threshold L is 62.8m, vehicle speed V is 80-90km/h, vehicle distance threshold L is 75.4 m, vehicle speed V is 90-100km/h, vehicle distance threshold L is 89.1m, vehicle speed V is 100-110km/h, vehicle distance threshold L is 103.9m, vehicle speed V is 110-120km/h, vehicle distance valve The value L is 120m. Since the vehicle distance threshold L0 is dynamically calculated according to the vehicle speed V, and the vehicle speed V is collected in real time, the obtained data is highly applicable, accurate and effective. The speed calculation range is from 0-120km/h, covering all possible speeds during daily driving, which is highly practical. the

As an improved specific implementation, the formula for calculating the distance threshold L0 between the radar sensor 2 and the obstacle is

$\mathrm{<span\; class="notranslate">\; S</span>}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>\frac{{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}}{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span>\frac{\mathrm{<span\; class="notranslate">\; \&mu;g</span>}{{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{\mathrm{<span\; class="notranslate">\; twenty\; four</span>}}<span\; class="notranslate">\; +</span>\frac{{{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; \&mu;g</span>}}$

V1: the driving speed of the car before braking;

t1: The reaction time of the driver, the action time of most people in an emergency is about 1 second;

t2: the time from depressing the pedal to generating the braking force, the value is 0.10-0.15s;

After the car generates braking force, the car acceleration a increases linearly, and a ₁ = μg;

$\mathrm{<span\; class="notranslate">\; a</span>}<span\; class="notranslate">\; =</span>\frac{{{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}^{\mathrm{<span\; class="notranslate">\; t</span>}}}{{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; \&mu;gt</span>}}{{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}}$

a1: the maximum value of the vehicle acceleration a;

μ: coefficient of friction between the vehicle and the ground, take μ=0.8;

g: gravity coefficient, take g=9.8m/s ² ;

t3: car acceleration growth time, generally 0.15-0.20s. the

Assuming that the braking distance S is calculated from when the driver encounters an emergency, S can be divided into the following parts: the distance S1 from when the driver encounters an emergency to when the driver suddenly steps on the brake pedal; The distance S2 from the brake pedal to the braking force generated by the car; the distance S3 from the beginning of the braking force generated by the car to the maximum value, the distance S4 from the maximum braking force to the stop of the car, and a is the acceleration of the car after the braking force is generated. As shown in Figure 3,

S ₁ =V ₁ t ₁

S ₂ =V ₁ t ₂

V1: the driving speed of the car before braking;

t1: The reaction time of the driver: about 0.5 seconds under normal conditions, and about 1 second for most people in emergency situations;

t2: the time from depressing the pedal to generating braking force, this system is 0.10-0.15s;

After the car generates braking force, the car acceleration a increases linearly, and a ₁ = μg;

$\mathrm{<span\; class="notranslate">\; a</span>}<span\; class="notranslate">\; =</span>\frac{{{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}^{\mathrm{<span\; class="notranslate">\; t</span>}}}{{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; \&mu;gt</span>}}{{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}}$

a1: the maximum value of the vehicle acceleration a;

μ: coefficient of friction between the vehicle and the ground, take μ=0.8;

g: gravity coefficient, take g=9.8m/s ² ;

t3: car acceleration growth time, generally 0.15-0.20s;

${\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; =</span>{<span\; class="notranslate">\; \&Integral;</span>}_{\mathrm{<span\; class="notranslate">\; 0</span>}}^{{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}}\mathrm{<span\; class="notranslate">\; vdt</span>}<span\; class="notranslate">\; =</span>{<span\; class="notranslate">\; \&Integral;</span>}_{\mathrm{<span\; class="notranslate">\; 0</span>}}^{{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}}{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; \&Integral;</span>\mathrm{<span\; class="notranslate">\; atdt</span>}<span\; class="notranslate">\; =</span>{<span\; class="notranslate">\; \&Integral;</span>}_{\mathrm{<span\; class="notranslate">\; 0</span>}}^{{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; -</span>\frac{{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}{\mathrm{<span\; class="notranslate">\; 2</span>}{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}}{\mathrm{<span\; class="notranslate">\; t</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span>\mathrm{<span\; class="notranslate">\; dt</span>}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; -</span>\frac{\mathrm{<span\; class="notranslate">\; \&mu;g</span>}}{\mathrm{<span\; class="notranslate">\; 6</span>}}{{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}$

${\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; -</span>{<span\; class="notranslate">\; \&Integral;</span>}_{\mathrm{<span\; class="notranslate">\; 0</span>}}^{{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}}\mathrm{<span\; class="notranslate">\; adt</span>}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; -</span>{<span\; class="notranslate">\; \&Integral;</span>}_{\mathrm{<span\; class="notranslate">\; 0</span>}}^{{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}}\frac{{{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}^{\mathrm{<span\; class="notranslate">\; t</span>}}}{{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}}\mathrm{<span\; class="notranslate">\; dt</span>}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; -</span>\frac{{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}}{\mathrm{<span\; class="notranslate">\; 2</span>}}$

V3: the final velocity of the t3 stage;

${\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; v</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}}{{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; v</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}{{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}<span\; class="notranslate">\; -</span>\frac{{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}}{\mathrm{<span\; class="notranslate">\; 2</span>}}$

${\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}<span\; class="notranslate">\; =</span>{<span\; class="notranslate">\; \&Integral;</span>}_{\mathrm{<span\; class="notranslate">\; 0</span>}}^{{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}}\mathrm{<span\; class="notranslate">\; vdt</span>}<span\; class="notranslate">\; =</span>\frac{{{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{\mathrm{<span\; class="notranslate">\; 2</span>}{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; 2</span>}{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; (</span>{{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; +</span>\frac{{{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}{{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{\mathrm{<span\; class="notranslate">\; 4</span>}}<span\; class="notranslate">\; )</span>$

$\mathrm{<span\; class="notranslate">\; S</span>}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>\frac{{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}}{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span>\frac{\mathrm{<span\; class="notranslate">\; \&mu;g</span>}{{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{\mathrm{<span\; class="notranslate">\; twenty\; four</span>}}<span\; class="notranslate">\; +</span>\frac{{{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; \&mu;g</span>}}$

According to the above formula, the dynamic calculation of the vehicle distance threshold L0 is very accurate and the error is small. As an active safety system, the accelerator anti-misstepping system should be calculated as close as possible to the actual situation. In this process, the braking process is accurately divided into sections, and the sum is calculated separately by using the integral form. The value is accurate, the error is small, and the calculation result is close to the actual situation. It is an ideal calculation method. the

Claims (5)

1. the gas based on DSP2812 controller is stepped on determination methods by mistake, it is characterized in that including acceleration pick-up (1), radar sensor (2) and tachogenerator (3), described acceleration pick-up (1), radar sensor (2) and tachogenerator (3) are connected with DSP2812 controller (4), also include following steps:

1) set Das Gaspedal acceleration/accel threshold values (a0) at value 55-85m/s2;

2) automobile real-time speed (V) sampled value that DSP2812 controller (4) is surveyed according to tachogenerator (3) is calculated the spacing threshold values (L0) between radar sensor (2) and obstacle;

3) acceleration pick-up (1) gathers Das Gaspedal acceleration/accel (a), and distance (L) between radar sensor (2) collection and obstacle, is then transported to DSP2812 controller (4);

4) DSP2812 controller (4) is carried out following operation:

[1] if Das Gaspedal acceleration/accel (a) < Das Gaspedal acceleration/accel threshold values (a0) system executive command not;

[2] if distance (L) > radar sensor and obstacle spacing threshold values (L0) between Das Gaspedal acceleration/accel (a) > Das Gaspedal acceleration/accel threshold values (a0) and radar sensor (2) and obstacle, system is executive command not, and driver intention is anxious step on the accelerator;

[3] if distance (L) < radar sensor and obstacle spacing threshold values (L0) system executive command between Das Gaspedal acceleration/accel (a) > Das Gaspedal acceleration/accel threshold values (a0) and radar sensor and obstacle, system is judged as chaufeur and touches on the brake by mistake, vehicle stop fuel feeding emergency braking.

2. a kind of gas based on DSP2812 controller according to claim 1 is stepped on determination methods by mistake, it is characterized in that described radar sensor (2) includes waveform generation module, millimeter wave transmitting and receiver module, antenna and intermediate frequency pre-processing module, waveform generation module produces waveform modulated Voltage-output to millimeter wave transmitting and receiver module, millimeter wave transmitting and receiver module produce millimeter wave frequency band transmitted waveform and go out by aerial radiation, simultaneously by antenna reception target reflection echo, echo is down coversion output intermediate frequency Beat Signal after millimeter wave transmitting and receiver module, intermediate frequency pre-processing module is clapped signal to middle frequency difference and is carried out automatic gain control, output signal is sampled and analyzing and processing through DSP2812 controller (4).

3. the gas based on DSP2812 controller according to claim 2 is stepped on determination methods by mistake, it is characterized in that described radar sensor (2) is millimeter wave radar sensor, described radar sensor (2) search angle is 34-36 degree, and described radar sensor (2) detection range minimum value is 120 meters.

4. the gas based on DSP2812 controller according to claim 3 is stepped on determination methods by mistake, it is characterized in that the speed of a motor vehicle (V) is for 0-10km/h, spacing threshold values (L) is 4.2m, the speed of a motor vehicle (V) is 10-30km/h, spacing threshold values (L) is 16m, the speed of a motor vehicle (V) is 30-40km/h, spacing threshold values (L) is 22.9m, the speed of a motor vehicle (V) is 40-50km/h, spacing threshold values (L) is 31.3m, the speed of a motor vehicle (V) is 50-60km/h, spacing threshold values (L) is 40.7m, the speed of a motor vehicle (V) is 60-70km/h, spacing threshold values (L) is 51.2m, the speed of a motor vehicle (V) is 70-80km/h, spacing threshold values (L) is 62.8m, the speed of a motor vehicle (V) is 80-90km/h, spacing threshold values (L) is 75.4m, the speed of a motor vehicle (V) is 90-100km/h, spacing threshold values (L) is 89.1m, the speed of a motor vehicle (V) is 100-110km/h, spacing threshold values (L) is 103.9m, the speed of a motor vehicle (V) is 110-120km/h, spacing threshold values (L) is 120m.

5. the gas based on DSP2812 controller according to claim 3 is stepped on determination methods by mistake, it is characterized in that spacing threshold values (L0) computing formula between described radar sensor (2) and obstacle is

$S=S_1+S_2+S_3+S_4=V_1(t_1+t_2+\frac{t_3}{2})-\frac{\mathrm{\&mu;g}{t_3}^2}{24}+\frac{{V_1}^2}{2\mathrm{\&mu;g}}$

V1: the moving velocity before braking automobile;

T1: chaufeur reacts opening time, in emergency circumstances approximately needs 1 second the opening time of most people;

T2: from push down on the pedal to the time that produces braking force, value is 0.10-0.15s;

Automobile produces after braking force, and pickup a is linear growth, and a ₁=μ g;

$a=\frac{{a_1}^t}{t_3}=\frac{\mathrm{\&mu;gt}}{t_3}$

A1: be the maxim of pickup a;

μ: the friction coefficient on car and ground, get μ=0.8;

G: gravity coefficient, get g=9.8m/s ²;

T3: pickup build up time, value is 0.15-0.20s.