Ultrasonic radar system based on silicon microphone array and obstacle detection method

Abstract

The invention discloses an ultrasonic radar system based on a silicon microphone array and an obstacle detection method, and the ultrasonic radar system comprises at least one ultrasonic sensor which is configured to transmit an ultrasonic signal; a silicon microphone array configured to receive a reflected signal of the ultrasonic wave; the silicon microphone array is formed by arranging three silicon microphone sensors on the periphery of each ultrasonic sensor, and comprises two silicon microphone sensors arranged in the horizontal direction and a silicon microphone sensor arranged in the vertical direction; the processing unit is configured to calculate the horizontal position of the obstacle based on the phase difference between the two silicon microphone sensors in the horizontal direction, calculate the vertical position L of the obstacle based on the phase difference between the silicon microphone sensor in the vertical direction and the silicon microphone sensor in the horizontal direction and determine the height h of the obstacle based on the installation height H of the ultrasonic sensor, and h = H-L. The installation number of ultrasonic sensors can be reduced, the cost is reduced, and the positions of obstacles in the horizontal and vertical directions are accurately measured.

Description

Technical Field

[0001] This invention relates to the field of ultrasonic technology, specifically to an ultrasonic radar system and obstacle detection method based on a silicon microphone array. Background Technology

[0002] To meet specific requirements for use in vehicles, automotive ultrasonic radar sensors employ ceramic plates mounted inside an aluminum housing to achieve both transmitting and receiving capabilities while remaining waterproof.

[0003] See Figure 1 As shown, the ultrasonic radar sensor, or ultrasonic sensor 10 for short, includes a ceramic plate 11, which is housed within an aluminum shell 12 and sealed with waterproof adhesive 13. The working principle of this ultrasonic sensor is to apply an alternating pulse voltage (such as 51kHz, 58kHz, etc.) to the ceramic plate 11. Under the action of the alternating voltage, the ceramic plate 11 undergoes mechanical deformation, causing the aluminum shell in close contact with it to deform. The aluminum shell 12, in turn, causes the surrounding air to deform, transmitting signals into the air. When the deformed air encounters an obstacle 20, it is reflected back and acts on the surface of the aluminum shell 12, causing a slight deformation of the aluminum shell 12 and resulting in a slight voltage signal generated by the mechanical deformation of the ceramic plate 11. This voltage signal is amplified and processed by a DSP to identify the obstacle signal and its distance and orientation, thus realizing the ultrasonic sensor's detection function.

[0004] To achieve better transmit power and receive sensitivity, please refer to the above. Figure 2 As shown, holes are typically made in the bumper 30 to expose the aluminum housing of the ultrasonic sensor to the air, which results in the following drawbacks:

[0005] Disadvantage 1: If holes need to be drilled in the bumper, the bumper manufacturer needs to make a punching mold, which is not cheap and will also increase the labor cost of punching.

[0006] Disadvantage 2: Car bumpers are usually painted the same color as the car body. The bumper will be painted the same color as the car body. Since the ultrasonic sensor is attached to the bumper, the surface of the ultrasonic sensor's aluminum shell must also be painted the same color as the bumper. In other words, the ultrasonic sensor also needs to be painted, which increases the cost of the ultrasonic sensor.

[0007] Disadvantage 3: Because the bumper needs to have holes, there will be some gap between the ultrasonic sensor and the bumper, which will make the bumper look less attractive than when there are no holes.

[0008] Disadvantage 4: Existing ultrasonic sensors generally have a horizontal angle of only about 120 degrees. In order to achieve detection around the vehicle, the system usually needs to install 12 sensors, which increases the system cost.

[0009] Shortcoming 5: Existing ultrasonic sensors, in order to meet automotive requirements (such as waterproofing), adopt a transceiver integration, with a maximum detection distance of only about 5 meters. Summary of the Invention

[0010] In view of this, in order to solve the above-mentioned technical problems, the purpose of this invention is to propose an ultrasonic radar system and obstacle detection method based on a silicon microphone array, which can reduce the number of ultrasonic sensors installed, reduce costs, and accurately measure the horizontal and vertical positions of obstacles.

[0011] The technical solution adopted is as follows:

[0012] The present invention provides an ultrasonic radar system based on a silicon microphone array, comprising:

[0013] At least one ultrasonic sensor configured to emit ultrasonic signals;

[0014] A silicon microphone array configured to receive reflected signals from ultrasonic waves; the silicon microphone array consists of three silicon microphone sensors arranged around each ultrasonic sensor, including two horizontally arranged silicon microphone sensors and one vertically arranged silicon microphone sensor.

[0015] The processing unit is configured to calculate the horizontal position of the obstacle based on the phase difference Δϕ1 between two silicon microphone sensors in the horizontal direction, calculate the vertical position L of the obstacle based on the phase difference Δϕ2 between the vertical silicon microphone sensor and the horizontal silicon microphone sensor, and determine the height h of the obstacle based on the installation height H of the ultrasonic sensor and the detected vertical position L of the obstacle, where h=HL.

[0016] Furthermore, the processing unit combines the horizontal position of the obstacle with a comparison between the obstacle height h and a threshold to determine whether to avoid the obstacle. When the horizontal position of the obstacle is on the driving path and the vertical height h of the obstacle is less than or equal to the threshold, a driving operation of running over the obstacle is performed. When the horizontal position of the obstacle is on the driving path and h is greater than the threshold, an avoidance operation is performed. When the horizontal position of the obstacle is not on the driving path, a driving operation is performed regardless of the obstacle height h.

[0017] Furthermore, the threshold is 25cm.

[0018] Furthermore, the vertically arranged silicon microphone sensor is located below the two horizontally arranged silicon microphone sensors.

[0019] Furthermore, the ultrasonic sensors are installed on the front and rear bumpers of the vehicle, and the number of ultrasonic sensors on the front and rear bumpers is less than 6 each.

[0020] Furthermore, the ultrasonic sensor is embedded inside the bumper using a hole-free installation method.

[0021] An obstacle detection method of the present invention uses the aforementioned ultrasonic radar system based on a silicon microphone array for detection, and the detection steps include the following:

[0022] S1. The ultrasonic sensor emits ultrasonic signals;

[0023] S2. The silicon microphone array receives the reflected signal of the ultrasonic wave;

[0024] S3. The processing unit calculates the horizontal position of the obstacle based on the phase difference Δϕ1 between the two silicon microphone sensors in the horizontal direction, calculates the vertical position L of the obstacle based on the phase difference Δϕ2 between the vertical silicon microphone sensor and the horizontal silicon microphone sensor, and determines the height h of the obstacle based on the installation height H of the ultrasonic sensor and the detected vertical position L of the obstacle, where h=HL.

[0025] Furthermore, in S3, the processing unit combines the horizontal position of the obstacle with a comparison between the obstacle height h and a threshold to determine whether to avoid the obstacle. When the horizontal position of the obstacle is on the driving path and the vertical height h of the obstacle is less than or equal to the threshold, a running operation is performed. When the horizontal position of the obstacle is on the driving path and h is greater than the threshold, an avoidance operation is performed. When the horizontal position of the obstacle is not on the driving path, a driving operation is performed regardless of the obstacle height.

[0026] The present invention provides a computer-readable storage medium storing a computer program configured to perform the steps involved in the obstacle detection method when the program is run.

[0027] The beneficial effects of this invention are as follows:

[0028] Because a silicon microphone array is set up, which is configured to receive reflected ultrasonic signals; the silicon microphone array consists of three silicon microphone sensors arranged around each ultrasonic sensor, including two horizontally arranged silicon microphone sensors and one vertically arranged silicon microphone sensor, so that the processing unit can accurately measure the horizontal and vertical positions of obstacles based on the silicon microphone array; and the use of silicon microphone array can reduce the number of ultrasonic sensors installed, and the ultrasonic sensors can be installed without openings, thus reducing costs. Attached Figure Description

[0029] To more clearly illustrate the technical solution of the present invention, the following will briefly introduce the background technology and the drawings used in the specific embodiments. The drawings in the description are only for the purpose of facilitating technical understanding. For those skilled in the art, other drawings can be obtained by appropriate modifications based on these drawings without creative effort.

[0030] Figure 1This is a schematic diagram illustrating the working principle of an ultrasonic sensor in the background art.

[0031] Figure 2 This is a schematic diagram of the installation structure of an ultrasonic sensor in the background art.

[0032] Figure 3 This is a schematic diagram of a structure with a silicon microphone array and an ultrasonic sensor installed on the guardrail.

[0033] Figure 4 This is a structural block diagram of the ultrasonic radar system of the present invention.

[0034] Figure 5 This is a schematic diagram of the ultrasonic radar system of the present invention for detecting the height of obstacles.

[0035] Figure 6 This is a flowchart illustrating an obstacle detection method. Detailed Implementation

[0036] The present invention will be described in detail below through specific embodiments. However, the uses and purposes of these exemplary embodiments are only for illustrating the present invention and do not constitute any limitation on the actual protection scope of the present invention, nor are they intended to limit the protection scope of the present invention to this.

[0037] Example 1

[0038] See Figure 3 As shown, this embodiment of an ultrasonic radar system based on a silicon microphone array includes an ultrasonic sensor 10, a silicon microphone array 40, and a processing unit 50. The ultrasonic sensors are mounted on the front and rear bumpers of the vehicle. The number of ultrasonic sensors on the front and rear bumpers is less than six, for example, three, four, or five. The ultrasonic sensors are embedded inside the bumpers using a hole-free mounting method. Figure 4 The ultrasonic sensor is shown by dashed lines as it is installed inside the bumper without the need for drilling.

[0039] An ultrasonic sensor is configured to emit ultrasonic signals. In one specific implementation, the transmitting function of the ultrasonic sensor may be retained only, i.e., it may be configured to emit only ultrasonic signals.

[0040] The silicon microphone array 40 is configured to receive reflected signals from ultrasonic waves. The silicon microphone array consists of three silicon microphone sensors arranged around each ultrasonic sensor, including two horizontally arranged silicon microphone sensors 41 and one vertically arranged silicon microphone sensor 42. The silicon microphone sensors are MEMS silicon microphone sensors with a horizontal receiving angle ≥180°, and theoretically up to 360°.

[0041] The processing unit 50 is configured to calculate the horizontal position of the obstacle based on the phase difference Δϕ1 between two silicon microphone sensors 41 in the horizontal direction, calculate the vertical position L of the obstacle based on the phase difference Δϕ2 between the silicon microphone sensor 42 in the vertical direction and the silicon microphone sensor 41 in the horizontal direction, and determine the height h of the obstacle based on the installation height H of the ultrasonic sensor and the detected vertical position L of the obstacle, where h=HL.

[0042] The processing unit combines the horizontal position of the obstacle with a comparison between the obstacle's height h and a threshold to determine whether to avoid the obstacle. The specific execution operations are as follows:

[0043] When the obstacle is horizontally located in the driving path and the vertical height of the obstacle h is less than or equal to the threshold, the driving operation of crushing is performed.

[0044] When the obstacle is horizontally located within the driving path, an avoidance operation is performed if h > the threshold.

[0045] When the obstacle is not located in the driving path, the driving operation is performed regardless of the obstacle's height h.

[0046] The threshold is generally below 30cm, including but not limited to, for example, a threshold of 25cm.

[0047] In one specific implementation, the vertically arranged silicon microphone sensor is located below the two horizontally arranged silicon microphone sensors.

[0048] With the silicon microphone array, ultrasonic sensors can be embedded inside the bumper without the need for drilling.

[0049] This embodiment of an obstacle detection method employs an ultrasonic radar system based on a silicon microphone array for detection. The detection steps include the following:

[0050] S1. The ultrasonic sensor emits ultrasonic signals;

[0051] S2. The silicon microphone array receives the reflected signal of the ultrasonic wave;

[0052] S3. The processing unit calculates the horizontal position of the obstacle based on the phase difference Δϕ1 between the two silicon microphone sensors in the horizontal direction, calculates the vertical position L of the obstacle based on the phase difference Δϕ2 between the silicon microphone sensor in the vertical direction and the silicon microphone sensor in the horizontal direction, and determines the height h of the obstacle based on the installation height H of the ultrasonic sensor and the detected vertical position L of the obstacle, where h=HL;

[0053] The processing unit combines the horizontal position of the obstacle with a comparison between the obstacle height h and a threshold to determine whether to avoid the obstacle. When the horizontal position of the obstacle is on the driving path and the vertical height h of the obstacle is less than or equal to the threshold, the driving operation of running over the obstacle is performed. When the horizontal position of the obstacle is on the driving path and h is greater than the threshold, the avoidance operation is performed. When the horizontal position of the obstacle is not on the driving path, the driving operation is performed regardless of the obstacle height.

[0054] In response to the five shortcomings mentioned in the background art, the following will explain step by step how the ultrasonic radar system based on silicon microphone array in this embodiment overcomes the above five shortcomings.

[0055] I. Regarding shortcomings 4 and 5 mentioned in the background technology:

[0056] 1. Without changing the existing ultrasonic sensor and installation method, a silicon microphone sensor is added to the bumper to replace the ultrasonic sensor and receive or simultaneously receive ultrasonic signals reflected by obstacles;

[0057] 2. Silicon microphone sensors are commonly used for receiving sound waves, such as in mobile phone microphones and conference equipment microphones. Compared to earlier electret microphone sensors, their advantages are high sensitivity and wide angle (theoretically up to 360 degrees).

[0058] 3. As mentioned in point 2 above, the high sensitivity of the silicon microphone sensor allows for a longer detection distance without changing the ultrasonic sensor and its installation method. For example, the original maximum detection distance of 5 meters can be increased to 9 meters or even further. If this is used in the AEB emergency braking function of automobiles, it can detect distant obstacles earlier, thus providing more reaction time, improving AEB performance, reducing collision accidents, and reducing property damage (vehicles, other objects on the road, etc.) and personal injury (drivers, passengers, pedestrians, etc.).

[0059] 4. As mentioned in point 2 above, the silicon microphone sensor has a wider receiving angle, theoretically capable of 360-degree reception. Compared to the original ultrasonic sensor, which only has a receiving angle of about 120 degrees and requires 12 ultrasonic sensors in the entire vehicle, the silicon microphone sensor can reduce the number of ultrasonic sensors. In extreme cases, it is possible to reduce the original 12 ultrasonic sensors (6 in the front bumper and 6 in the rear bumper) to 8. For example, if there were originally 6 sensors in the front or rear bumper, adding the silicon microphone sensor can reduce the number of ultrasonic sensors to 4. Figure 3 As shown.

[0060] Using silicon microphones enables longer detection ranges and reduces the number of ultrasonic sensors required.

[0061] II. Regarding the shortcomings mentioned in the background technology:

[0062] 1) Keep the ultrasonic sensor the same, change the installation method, and add a silicon microphone sensor;

[0063] 2) The original bumper installation with holes has been changed to a hole-free installation;

[0064] 3) Installation without drilling holes will result in reduced transmission power and shortened detection range;

[0065] 4) To address the issue in point 3), a silicon microphone sensor is added to receive ultrasonic signals. Because the silicon microphone sensor has high receiving sensitivity, it can effectively compensate for the reduced transmission power and shortened detection distance caused by not having an opening. Ultimately, the system's maximum detection distance is comparable to the previous system, such as a maximum detection distance of about 5 meters.

[0066] 5. Based on 1)-4) above, under the condition that the detection distance remains unchanged, the silicon microphone sensor can effectively solve the appearance problems of needing to open holes in the bumper, needing to paint the probe, and having gaps between the probe and the bumper;

[0067] Furthermore, as discussed in the first point, the number of system probes can be reduced, thereby lowering the system cost.

[0068] III. While overcoming shortcomings 1-5, performance is improved.

[0069] (1) To detect the position of obstacles in the horizontal direction or the height of obstacles in the vertical direction, ultrasonic sensors can only be implemented by system-level algorithms, not by ultrasonic sensors alone. Moreover, the detection accuracy of system-level algorithms is limited. In contrast, a single silicon microphone sensor only supports the measurement of the horizontal azimuth angle and does not have the ability to detect the vertical height.

[0070] (2). In order to enable the ultrasonic sensor to detect the position of obstacles in the horizontal direction and the height of obstacles in the vertical direction, three silicon microphone sensors are arranged around each ultrasonic sensor, two in the horizontal direction and one in the vertical direction. The silicon microphone sensor arranged in the vertical direction is below the two silicon microphone sensors arranged in the horizontal direction.

[0071] (3) Based on the detection principle of silicon microphone sensors, when two silicon microphone sensors are about 3mm apart, the principle of phase difference can be used to detect the horizontal or vertical position of obstacles. Knowing the vertical position of the obstacle is equivalent to knowing its height, because the installation height H of the ultrasonic sensor is known in advance. Subtracting the vertical position L of the obstacle from the installation height gives the obstacle height h, i.e., h=HL. Knowing the obstacle height, the system can determine whether the ground obstacle can be run over or collide with the vehicle's bumper during parking algorithm control, thus parking the car better without damaging the bumper. For example, if the system recognizes that the limit bar is low enough to run over, it should consider avoiding it if it recognizes a 30cm high curb, to prevent the 30cm curb from damaging the bumper, because the lowest position of a typical vehicle bumper is below 30cm, such as 25cm. This lowest position can be stored in the system as a threshold for comparison and judgment.

[0072] See Figure 5 As shown, if the installation height is H and the vertical position of the detected obstacle is L, then the obstacle height h = HL.

[0073] The position of an obstacle in three-dimensional space needs to be determined by two independent dimensions:

[0074] Horizontal position: calculated from the phase difference Δϕ1 of the horizontal silicon microphone pair;

[0075] Vertical position: calculated from the phase difference Δϕ2 between the vertical silicon microphone pairs.

[0076] The horizontal position is used to determine whether it is on the path, and the vertical position L is the vertical distance from the top of the obstacle to the ultrasonic sensor, which is used to further calculate the obstacle height h.

[0077] The algorithm is executed as shown in Table 1 below, taking a threshold of 25cm as an example.

[0078] Table 1

[0079] Horizontal position obstacle height h Control Action On the path ≤25cm Rolling driving On the path >25cm Emergency braking / steering (evasive maneuver) Not on the path any height Normal driving

[0080] In summary, using a silicon microphone array can achieve several technical benefits, including longer detection distance, no need to drill holes in the bumper, no need to paint the probe, better appearance, obstacle position detection in both horizontal and vertical directions, and reduced system cost by reducing the number of ultrasonic sensors in the system.

[0081] Example 2

[0082] This embodiment provides a computer-readable storage medium storing a computer program, wherein the computer program is configured to execute the steps involved in the obstacle detection method described in Embodiment 1 above when it is run.

[0083] Computer-readable storage media can be magnetic random access memory (FRAM), read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), flash memory, magnetic surface memory, optical disc, or compact disc read-only memory (CD-ROM), etc.; it can also be various devices including one or any combination of the above-mentioned memories, such as mobile phones, computers, tablet devices, personal digital assistants, etc. When the computer program stored in the computer-readable storage medium is executed by a processor, it implements the steps involved in the obstacle detection method described in Embodiment 1 above, such as... Figure 6 The control logic flow is shown below.

[0084] The detailed descriptions listed above are merely specific illustrations of feasible embodiments of the present invention and are not intended to limit the scope of protection of the present invention. All equivalent embodiments or modifications made without departing from the spirit of the present invention should be included within the scope of protection of the present invention.

Claims

1. A silicon microphone array based ultrasonic radar system, characterized by The application comprises: at least one ultrasonic sensor configured to emit ultrasonic signals; a silicon microphone array configured to receive reflected signals of the ultrasonic waves; the silicon microphone array is arranged with three silicon microphone sensors around each ultrasonic sensor, including two silicon microphone sensors arranged horizontally and one silicon microphone sensor arranged vertically; a processing unit configured to calculate the horizontal position of the obstacle based on the phase difference ΔΦ1 of the two silicon microphone sensors arranged horizontally, calculate the vertical position L of the obstacle based on the phase difference ΔΦ2 of the silicon microphone sensor arranged vertically and the silicon microphone sensor arranged horizontally, and determine the height h of the obstacle based on the installation height H of the ultrasonic sensor and the detected vertical position L of the obstacle, where h=H-L.

2. The silicon-based matrix array based ultrasonic radar system of claim 1, wherein, The processing unit combines the horizontal position of the obstacle and determines whether to avoid the obstacle based on the comparison between the height h of the obstacle and a threshold value; when the horizontal position of the obstacle is located on the driving path and the vertical height h of the obstacle is less than or equal to the threshold value, the rolling driving operation is performed; when the horizontal position of the obstacle is located on the driving path and h is greater than the threshold value, the avoidance operation is performed; when the horizontal position of the obstacle is not located on the driving path, the driving operation is performed regardless of the height h of the obstacle.

3. The silicon microphone array based ultrasonic radar system of claim 1, wherein, The threshold value is 25 cm.

4. The silicon microphone array based ultrasonic radar system of claim 1, wherein, The silicon microphone sensor arranged vertically is located below the two silicon microphone sensors arranged horizontally.

5. The silicon microphone array based ultrasonic radar system of claim 1, wherein, The ultrasonic sensors are installed on the front and rear bumpers of the vehicle, and the number of ultrasonic sensors on the front and rear bumpers of the vehicle is less than 6 respectively.

6. The silicon microphone array based ultrasonic radar system of claim 1, wherein, The ultrasonic sensors are embedded in the bumpers in a non-penetrating installation mode.

7. An obstacle detection method, which is detected by the silicon microphone array-based ultrasonic radar system of any one of claims 1-6, and the detection steps comprise the following: S1. The ultrasonic sensor emits ultrasonic signals; S2. The silicon microphone array receives reflected signals of the ultrasonic waves; S3. The processing unit calculates the horizontal position of the obstacle based on the phase difference ΔΦ1 of the two silicon microphone sensors arranged horizontally, calculates the vertical position L of the obstacle based on the phase difference ΔΦ2 of the silicon microphone sensor arranged vertically and the silicon microphone sensor arranged horizontally, and determines the height h of the obstacle based on the installation height H of the ultrasonic sensor and the detected vertical position L of the obstacle, where h=H-L.

8. The obstacle detection method according to claim 7, wherein In S3, the processing unit combines the horizontal position of the obstacle and determines whether to avoid the obstacle based on the comparison between the height h of the obstacle and a threshold value; when the horizontal position of the obstacle is located on the driving path and the vertical height h of the obstacle is less than or equal to the threshold value, the rolling driving operation is performed; when the horizontal position of the obstacle is located on the driving path and h is greater than the threshold value, the avoidance operation is performed; when the horizontal position of the obstacle is not located on the driving path, the driving operation is performed regardless of the height h of the obstacle.

9. A computer readable storage medium, characterized in that, The storage medium stores a computer program, which is set to execute the steps involved in the obstacle detection method of claim 8 when running.

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