Method for distinguishing low obstacles on ground applied to ultrasonic detection

Abstract

The invention provides a method for distinguishing low obstacles on the ground applied to ultrasonic detection, which is used for distinguishing whether an object is a low obstacle or not by utilizing the characteristic that the sensor detects angle change under different driving frequencies while ensuring the detection degree of a vertical obstacle on the premise of not changing the mounting position of the sensor. If the obstacle is judged to be a low obstacle, the obstacle is filtered out through a software algorithm, the ultrasonic system is prevented from making an excessive reaction, and the system performance is improved. According to the method applied to ultrasonic detection and used for distinguishing the low obstacles on the ground, the same sensor is used for sending waves at different frequencies for three times, the obstacles are judged according to echo results, and the height of the obstacles is judged according to the echo height ratio of the last two frequencies. Low obstacles can be detected by one sensor, the detection efficiency is improved, and the detection cost is reduced.

Description

Technical Field

[0001] The invention relates to a method for distinguishing low obstacles on the ground by ultrasonic detection. Background Art

[0002] Due to the characteristics of ultrasonic waves, low obstacles on the ground usually form a collection of sound waves, making them easier to be detected by the system. However, due to their low height, this type of obstacle has little impact on the vehicle's driving. From the driver's perspective, they often do not want the ultrasonic system to overreact to these obstacles, such as issuing a warning sound to indicate that an obstacle is approaching, interrupting the automatic parking process, or even initiating automatic braking to avoid a collision.

[0003] In order to solve this problem, the existing foundation mainly adopts the following two methods: 1. Adjust the gain and threshold of echo signal processing, such as setting a lower gain, a larger threshold voltage or width, to filter low obstacles. However, this method often does not work or does not make up for the gains. The reason is that the echo of ground obstacles is very strong. If forced filtering is used, although low obstacles can be shielded, there is also a side effect - the detection of vertical obstacles becomes lower. This makes it easier for vehicles to collide with vertical obstacles, affecting the safety of vehicles and drivers.

[0004] 2. By adjusting the installation position of the sensor on the vehicle, such as increasing the upward tilt angle and height from the ground when the sensor is installed. This method is often difficult to implement because the installation position is limited by the vehicle's styling design. In addition, car manufacturers do not want the sensor to have a very abrupt appearance relative to the vehicle's appearance, otherwise it will affect the overall appearance of the vehicle.

[0005] At the same time, some manufacturers use algorithms to perform regional filtering in order to distinguish low obstacles, such as patent: CN111610531A. Although the distinction can be achieved, it is necessary to divide the detection area around the vehicle. Therefore, its detection threshold is limited. The data center can only divide the threshold for each different detection area before using the sensor. Once the obstacle is no longer within the divided threshold, it cannot be detected, which also affects the use of the sensor. Summary of the invention

[0006] The technical problem to be solved by the present invention is to provide a method for distinguishing low obstacles on the ground by ultrasonic detection, which ensures the detection degree of vertical obstacles without changing the installation position of the sensor, and distinguishes whether the object is a low obstacle by using the characteristic of the sensor detecting angle changes under different driving frequencies. If it is determined to be a low obstacle, it is filtered out by software algorithm to avoid the ultrasonic system from overreacting to it, thereby improving the system performance.

[0007] In order to solve the above technical problems, the technical solution of the present invention is: A method for distinguishing low obstacles on the ground by ultrasonic detection is provided. The ultrasonic sensor used integrates a microcontroller, an ultrasonic driving module and an ultrasonic receiving module. A piezoelectric transducer is extended outward from the ultrasonic sensor, and the other side is connected to the main controller. The detection method is as follows: The first step is to turn on the main controller and control the ultrasonic sensor to emit waves; In the second step, the main controller drives the sensor to emit ultrasonic waves of the first frequency; The third step is to detect whether the sensor detects an obstacle; if it is not detected, the detection ends; if it is detected, the next step of detection is carried out; Step 4: the main controller drives the sensor to emit ultrasonic waves of the second frequency; The fifth step is to detect whether the sensor detects an obstacle; if it is determined that there is no obstacle, the detection ends; if it is determined that there is an obstacle, the next step of detection is carried out; Step 6: Record the height of the first echo; Step 7: The main controller drives the sensor to emit ultrasonic waves of the third frequency; Step 8: Check whether the sensor detects an obstacle; if it is detected as no obstacle, the detection ends; if it is detected as yes, the next step of detection is performed; Step 9, record the height of the second echo; Step 10: Calculate and judge the ratio of the height of the first echo to the height of the second echo. If the ratio exceeds 0.5, the obstacle is judged to be a non-low obstacle, i.e., a valid obstacle. If the ratio is less than 0.5, the obstacle is judged to be a low obstacle, i.e., an invalid obstacle. Complete detection.

[0008] Furthermore, the third frequency is smaller than the first frequency, and the first frequency is smaller than the second frequency.

[0009] Furthermore, the first frequency is set to 58KHZ±0.5KHZ.

[0010] Furthermore, the second frequency is set to 60KHZ±0.5KHZ.

[0011] Furthermore, the third frequency is set to 56KHZ±0.5KHZ.

[0012] Furthermore, the ultrasonic sensor is configured as one, and the main controller drives the sensor to emit ultrasonic waves of different frequencies.

[0013] Furthermore, the ultrasonic receiving module is used to receive echoes of different frequencies and record echo heights.

[0014] Compared with the prior art, the present invention provides a method for distinguishing low ground obstacles by ultrasonic detection. The method uses the same sensor to send waves three times at different frequencies, judges the obstacles based on the echo results, and uses the echo height ratio of the last two frequencies to judge the height of the obstacle. This enables one sensor to detect low obstacles, improves detection efficiency, and reduces detection costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Attached Figure 1 A schematic flow chart of the method of the present invention is shown.

[0016] Attached Figure 2 A schematic structural diagram of the ultrasonic sensor used in the present invention is shown.

[0017] Attached Figure 3 A schematic diagram showing the -6 dB angle of the sound pressure emitted by the known ultrasonic sensor in the present invention, and the decrease in the detection angle caused by the increase in frequency.

[0018] Attached Figure 4 An experimental schematic diagram of the present invention for detecting low obstacles is shown.

[0019] Attached Figure 5 A schematic diagram showing the echo intensity of low-frequency waves emitted by the present invention to low obstacles.

[0020] Attached Figure 6 A schematic diagram showing the echo intensity of a low obstacle caused by the high-frequency wave of the present invention.

[0021] Attached Figure 7 An experimental schematic diagram of the present invention for detecting non-low obstacles is shown.

[0022] Attached Figure 8 A schematic diagram showing the echo intensity of low-frequency waves emitted by the present invention to non-low obstacles.

[0023] Attached Fig. 9 A schematic diagram showing the echo intensity of a high-frequency wave emitted to a non-low obstacle in the present invention.

[0024] Attached Fig.10 A graph showing experimental data of the relationship between the -6dB angle of the emitted sound pressure and the frequency of the present invention.

[0025] Attached Fig.11 The experimental data of the echo intensity against obstacles in the present invention are shown.

[0026] Among them: 1. Main controller, 2. Ultrasonic sensor, 3. Microcontroller, 4. Ultrasonic drive module, 5. Ultrasonic receiving module, 6. Piezoelectric transducer. DETAILED DESCRIPTION

[0027] In one embodiment, Figure 1 and 2 , a method for distinguishing low obstacles on the ground by ultrasonic detection, wherein the ultrasonic sensor used integrates a microcontroller 3, an ultrasonic driving module 4 and an ultrasonic receiving module 5: wherein the ultrasonic sensor extends outwardly with a piezoelectric transducer 6, and the other side is connected to the main controller 1, and the detection method thereof is as follows: The first step is to turn on the main controller 1 and control the ultrasonic sensor to emit waves; In the second step, the main controller drives the sensor to emit ultrasonic waves of the first frequency; The third step is to detect whether the sensor detects an obstacle; if it is not detected, the detection ends; if it is detected, the next step of detection is carried out; Step 4: the main controller drives the sensor to emit ultrasonic waves of the second frequency; The fifth step is to detect whether the sensor detects an obstacle; if it is determined that there is no obstacle, the detection ends; if it is determined that there is an obstacle, the next step of detection is carried out; Step 6: Record the height of the first echo; Step 7: The main controller drives the sensor to emit ultrasonic waves of the third frequency; Step 8: Check whether the sensor detects an obstacle; if it is detected as no obstacle, the detection ends; if it is detected as yes, the next step of detection is performed; Step 9, record the height of the second echo; Step 10: Calculate and judge the ratio of the height of the first echo to the height of the second echo. If the ratio exceeds 0.5, the obstacle is judged to be a non-low obstacle, i.e., a valid obstacle. If the ratio is less than 0.5, the obstacle is judged to be a low obstacle, i.e., an invalid obstacle. Complete detection.

[0028] In one embodiment, when the ultrasonic sensor's transmission wave comment increases, the -6dB angle of its transmitted sound pressure decreases, such as Figure 3 As shown, Figure 8 The specific experimental data is shown; therefore, when detecting a PVC water pipe with a length of 1m and a diameter of 70mm placed horizontally on the ground, that is, detecting a low obstacle, the echo height of the low-frequency wave and the high-frequency wave has obvious changes, such as Figure 4 and 5 shown.

[0029] However, when detecting a PVC water pipe with a length of 1m and a diameter of 70mm placed on the ground, that is, detecting a non-low obstacle, there is no obvious difference in the echo height of the low-frequency wave and the high-frequency wave; the specific experimental data are as follows: Fig. 9 shown.

[0030] Therefore, during the detection process, the height of the obstacle can be determined by the ratio of the echo heights of waves with different frequencies, which can more quickly and effectively determine whether the height of the obstacle affects the driving of the vehicle.

[0031] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than a limiting technical solution. Those skilled in the art should understand that those modifications or equivalent substitutions of the technical solution of the present invention that do not depart from the purpose and scope of the technical solution should be included in the scope of the claims of the present invention.

Claims

1. A method for distinguishing low obstacles on the ground by ultrasonic detection, wherein the ultrasonic sensor used integrates a microcontroller, an ultrasonic driving module and an ultrasonic receiving module: wherein a piezoelectric transducer is extended outward from the ultrasonic sensor, and the other side is connected to a main controller, and the characteristics are: The detection method is as follows: The first step is to turn on the main controller and control the ultrasonic sensor to emit waves; In the second step, the main controller drives the sensor to emit ultrasonic waves of the first frequency; The third step is to detect whether the sensor detects an obstacle; if it is not detected, the detection ends; if it is detected, the next step of detection is carried out; Step 4: the main controller drives the sensor to emit ultrasonic waves of the second frequency; The fifth step is to detect whether the sensor detects an obstacle; if it is determined that there is no obstacle, the detection ends; if it is determined that there is an obstacle, the next step of detection is carried out; Step 6: Record the height of the first echo; Step 7: The main controller drives the sensor to emit ultrasonic waves of the third frequency; Step 8: Check whether the sensor detects an obstacle; if it is detected as no obstacle, the detection ends; if it is detected as yes, the next step of detection is performed; Step 9, record the height of the second echo; Step 10: Calculate and judge the ratio of the height of the first echo to the height of the second echo. If the ratio exceeds 0.5, the obstacle is judged to be a non-low obstacle, i.e., a valid obstacle. If the ratio is less than 0.5, the obstacle is judged to be a low obstacle, i.e., an invalid obstacle. Complete detection.

2. The method for distinguishing low obstacles on the ground by ultrasonic detection according to claim 1, characterized in that: The third frequency is smaller than the first frequency, and the first frequency is smaller than the second frequency.

3. The method for distinguishing low obstacles on the ground by ultrasonic detection according to claim 1, characterized in that: The first frequency is set to 58KHZ±0.5KHZ.

4. The method for distinguishing low obstacles on the ground by ultrasonic detection according to claim 1, characterized in that: The second frequency is set to 60KHZ±0.5KHZ.

5. The method for distinguishing low obstacles on the ground by ultrasonic detection according to claim 1, characterized in that: The third frequency is set to 56KHZ±0.5KHZ.

6. The method for distinguishing low obstacles on the ground by ultrasonic detection according to claim 1, characterized in that: The ultrasonic sensor is arranged as one, and the main controller drives the sensor to emit ultrasonic waves of different frequencies.

7. The method for distinguishing low obstacles on the ground by ultrasonic detection according to claim 1, characterized in that: The ultrasonic receiving module is used to receive echoes of different frequencies and record the echo heights.

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