A method of detecting vehicle speed and acceleration

Abstract

The application discloses a kind of methods for detecting vehicle speed and acceleration, comprising the following steps: S1, after detecting trigger, judge trigger point position;S2, after detecting trigger, judge trigger point position;S3, after detecting trigger, judge trigger point position;S4, after detecting trigger, judge trigger point position;S5, after detecting trigger, judge trigger point position, the judgment identification logic of the three-point laser speed measurement method is modified again, so that it is more accurate and effective when calculating the speed and acceleration of large passenger and freight cars with more complex underbody structure, the three-point laser speed measurement method can be adapted to more complex measurement environment, so that the test result is more accurate and effective.

Description

Technical Field

[0001] This invention belongs to the field of motor vehicle exhaust emission testing technology, specifically relating to a method for detecting vehicle speed and acceleration. Background Technology

[0002] PM2.5 and nitrogen oxides emitted by motor vehicles have become primary sources of pollution. With the continuous improvement of the stability and accuracy of telemetry equipment, coupled with the accumulation of application experience, relevant telemetry standards have been developed and applied to control urban exhaust emissions. Telemetry equipment needs to measure vehicle speed and acceleration, and the three-point laser speed measuring device is one of the mainstream speed measuring devices. In a three-point laser speed measuring device, the distance between the three lasers is fixed. By collecting the time it takes to pass through the three laser points, two speeds, V1 and V2, can be calculated. The average speed of the vehicle passing through the three-point speed measuring device can then be calculated using V1 and V2. The acceleration of the vehicle during this passage can then be calculated using V1 and V2. The three laser points in the three-point laser speed measuring method are named A, B, and C. Normally, triggering points A, B, and C sequentially, or C, B, and A sequentially, is the correct order. However, due to the high chassis and complex undercarriage structure of large passenger and freight vehicles, the three-point speed measurement method may result in multiple consecutive triggers at a single point or an incorrect triggering sequence, making it impossible to accurately calculate speed and acceleration. Therefore, this application proposes a method for determining the speed and acceleration of large vehicles based on the three-point laser speed measurement method to solve the aforementioned problems. Summary of the Invention

[0003] In order to overcome the shortcomings of the prior art, the present invention aims to provide a method for detecting vehicle speed and acceleration to solve the problems mentioned in the background art.

[0004] The technical solution adopted by this invention to solve its technical problem is as follows: a system for detecting vehicle speed and acceleration, using a vehicle parameter measuring device for detection, wherein the vehicle parameter measuring device includes:

[0005] The system comprises a main unit, a laser emitting module, and a reflector. The laser emitting module is mounted on the main unit and includes a laser emitting module at point A, a laser emitting module at point B, and a laser emitting module at point C. The reflector has three surfaces, each corresponding to one of the positions of the laser emitting modules at points A, B, and C.

[0006] The detection method includes the following steps:

[0007] S1, When the laser emitting module detects a trigger, it determines the trigger point;

[0008] S1-1, When the trigger point is point A, record the data of point A and proceed to step S2;

[0009] S1-2, When the trigger point is point B, clear the current detection record and close the detection process;

[0010] S1-3, when the trigger point is point C, record the data at point C;

[0011] S2, When the laser emitting module detects a trigger, it determines the trigger point;

[0012] S2-1, When the trigger point is point B, record the data of point B and proceed to step S3;

[0013] S2-2, When the trigger point is point A, clear the current detection record and return to step S2;

[0014] S2-3: When the trigger point is point C, record the data at point C, delete the data for point A recorded in S1-1, and proceed to S4;

[0015] S3, when the laser emitting module detects a trigger, it determines the trigger point;

[0016] S3-1, When the trigger point is point C, record the data at point C, end the detection, and calculate the result;

[0017] S3-2, When the trigger point is point A or point B, clear the current detection record and return to step S3;

[0018] S4, When the laser emitting module detects a trigger, it determines the trigger point;

[0019] S4-1, When the trigger point is point B, record the data of point B and proceed to step S5;

[0020] S4-2, when the trigger point is point A, record the data of point A, delete the data of point C in step S1-3 or step S2-3, and return to step S2;

[0021] S4-3, When the trigger point is point C, delete the current detection record and return to step S4;

[0022] S5, when the laser emitting module detects a trigger, it determines the trigger point;

[0023] S5-1: When the trigger point is point A, record the data at point A, end the detection, and calculate the result;

[0024] S5-2, When the trigger point is point B or point C, delete the current detection record and return to step S5.

[0025] Preferably, the time interval between adjacent steps in the detection method is less than or equal to 1 second.

[0026] More preferably, the host and the reflector are mounted on the same plane via a base, which increases detection accuracy and reduces error.

[0027] More preferably, the laser emitting modules at points A, B, and C are all used to emit laser beams outward.

[0028] More preferably, the surface of the reflector is set perpendicular to the direction in which the laser beams emitted by each laser emitting module are emitted, thereby increasing detection accuracy and reducing errors.

[0029] More preferably, the reflector has multiple areas on its surface that can receive laser beams, thereby increasing the receiving area and reducing errors.

[0030] As can be seen from the above, the beneficial effects of this invention are as follows: This invention discloses a method for judging the speed acceleration of large vehicles based on the three-point laser speed measurement method, which solves the problem in the field of motor vehicle exhaust remote sensing technology that the three-point laser speed measurement method cannot effectively and accurately detect large passenger and freight vehicles. The key technical point is to modify the judgment and recognition logic of the three-point laser speed measurement method, making it more accurate and effective when calculating the speed acceleration of large passenger and freight vehicles with more complex undercarriage structures. This invention can make the three-point laser speed measurement method adapt to more complex measurement environments, making its test results more accurate and effective. Attached Figure Description

[0031] Figure 1 This is a flowchart of a method for detecting vehicle speed and acceleration according to the present invention;

[0032] Figures 2-3 This is a schematic diagram of the vehicle parameter measuring device in this invention.

[0033] The attached diagram is labeled as follows: 1. Main unit; 2. Laser emitting module; 2a. Point A emitting module; 2b. Point B emitting module; 2c. Point C emitting module; 3. Reflector surface; 4. Reflector. Detailed Implementation

[0034] The present application will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, only the parts relevant to the invention are shown in the accompanying drawings.

[0035] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0036] Example

[0037] Please see Figure 1A method for detecting vehicle speed and acceleration, the method using a vehicle parameter measuring device; the vehicle parameter measuring device includes: a host 1, a laser emitting module 2, and a reflector 4, the laser emitting module 2 being mounted on the host 1, the laser emitting module 2 including a laser emitting module 2a at point A, a laser emitting module 2b at point B, and a laser emitting module 2c at point C, the reflector 4 having three surfaces corresponding one-to-one with the positions of the laser emitting modules 2a, 2b, and 2c respectively.

[0038] When a vehicle passes the vehicle parameter measuring device, the laser emitting module 2 first detects a trigger. It then determines whether the trigger is from laser emitting module 2b at point B. If it is, the time data for passing through point B is deleted, and the detection process is closed. If it is from laser emitting module 2a at point A or laser emitting module 2c at point C, the data is saved. If laser emitting module 2a at point A is triggered, the ABC trigger sequence is entered, meaning laser emitting modules 2a, 2b, and 2b at point C are triggered sequentially to detect and save vehicle data. If laser emitting module 2c at point C is triggered, the CBA trigger sequence is entered, meaning laser emitting modules 2c, 2b, and 2c at point A are triggered sequentially to detect and save vehicle data.

[0039] When the vehicle passes the vehicle parameter measuring device, the laser emitting module 2 detects the vehicle signal. When the vehicle sequentially triggers the laser emitting modules 2a at point A, 2b at point B, and 2c at point C, or sequentially triggers the laser emitting modules 2c at point C, 2b at point B, and 2a at point A to detect the vehicle speed, the feedback is sent to the host 1. The distance, time, and speed of the vehicle passing through the laser emitting modules 2a at point A and 2b at point B are s1, t1, and v1, respectively. The distance, time, and speed of the vehicle passing through the laser emitting modules 2b at point B and 2c at point C are s2, t2, and v2, respectively. The vehicle speed is v = v1 + v2 / 2 = s1 / t1 + s2 / t2 / 2, and the vehicle acceleration is a = v1 - v2 / t1 + t2.

[0040] Example 2

[0041] When the laser emitting module at point A is triggered, the data of laser emitting module 2a at point A is saved, and a timer starts, waiting for the next trigger. It then determines whether the next trigger is triggered by laser emitting module 2a at point A or laser emitting module 2c at point C. If it is triggered by laser emitting module 2a at point A, the data for this trigger at point A is deleted. If it is triggered by laser emitting module 2c at point C, the previous data for point A is deleted, and the current data for point C is recorded, entering the CBA judgment sequence. If neither laser emitting module 2a at point A nor laser emitting module 2c at point C is triggered, then laser emitting module 2b at point B is triggered. Next, it checks whether the current trigger interval exceeds 1 second. If it exceeds 1 second, the data is invalid, and all the above data is deleted. If it is within 1 second, the trigger data for point B is saved. The timing data of laser emitting module 2b is recorded. When laser emitting module 2b at point B is triggered, timing begins, waiting for the next trigger. It is then determined whether the next trigger is laser emitting module 2c at point C. If so, the data at point C is recorded. Next, it is determined whether the current trigger interval exceeds 1 second. If it exceeds 1 second, the data is invalid, and all the above data is deleted. Otherwise, the vehicle speed and acceleration are calculated according to the formula in Example 1. If laser emitting module 2b at point B or laser emitting module 2a at point A is triggered, the current recording process is cleared, and the detection is repeated until laser emitting module 2c at point C is triggered. Then, it is determined whether the current trigger interval exceeds 1 second. If it exceeds 1 second, the data is invalid, and all the above data is deleted. Otherwise, the vehicle speed and acceleration are calculated according to the formula in Example 1.

[0042] Example 3

[0043] When laser emission module 2c at point C is triggered, the data at point C is recorded. The system then enters the CBA trigger sequence, begins timing, and waits for the next trigger. It checks whether the next trigger is from laser emission module 2a at point A or laser emission module 2c at point C. If it is from laser emission module 2a at point A, the previous data at point C is deleted, the data at point A is recorded, and the ABC trigger sequence is restarted. If it is from laser emission module 2c at point C, the current data at point C is deleted, and the detection is repeated until laser emission module 2b at point B is triggered. If neither laser emission module 2a at point A nor laser emission module 2c at point C is triggered... If the triggering interval is B-point laser emitting module 2b, then it is determined whether the triggering interval exceeds 1 second. If it exceeds 1 second, the data is invalid and all data is deleted. If it is within 1 second, the triggering time data of B-point laser emitting module 2b is saved. The system then waits for the next trigger and determines the next triggering position. If the next trigger is A-point laser emitting module 2a, the data at point A is recorded, and it is determined whether the triggering interval exceeds 1 second. If it exceeds 1 second, the data is invalid and all data is deleted. Otherwise, the vehicle speed and acceleration are calculated according to the formula in Example 1. If the next trigger is B-point laser emitting module 2B or C-point laser emitting module 2c, the current detection record is deleted, and the detection is repeated until A-point laser emitting module 2a is triggered. Then it is determined whether the triggering interval exceeds 1 second. If it exceeds 1 second, the data is invalid and all data is deleted. Otherwise, the vehicle speed and acceleration are calculated according to the formula in Example 1.

[0044] The above description is merely a preferred embodiment of this application and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of the invention involved in this application is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the inventive concept. For example, technical solutions formed by substituting the above features with (but not limited to) technical features with similar functions disclosed in this application.

[0045] Apart from the technical features described in the specification, the other technical features are known to those skilled in the art. To highlight the innovative features of this invention, the other technical features will not be described in detail here.

Claims

1. A method for detecting vehicle speed and acceleration, characterized in that, The detection is performed using a vehicle parameter measuring device, which includes: The host (1), laser emitting module (2) and reflector (4) are installed on the host (1). The laser emitting module (2) includes, from top to bottom, a laser emitting module A (2a), a laser emitting module B (2b) and a laser emitting module C (2c). The reflector (4) has three surfaces, which correspond one-to-one with the positions of the laser emitting modules A (2a), B (2b) and C (2c). The detection method includes the following steps: S1, when the laser emitting module (2) detects a trigger, it determines the trigger point; S1-1, When the trigger point is point A, record the data of point A and proceed to step S2; S1-2, When the trigger point is point B, clear the current detection record and close the detection process; S1-3, when the trigger point is point C, record the data of point C and proceed to step S4; S2, when the laser emitting module (2) detects a trigger, it determines the trigger point; S2-1, When the trigger point is point B, record the data of point B and proceed to step S3; S2-2, When the trigger point is point A, clear the current detection record and return to step S2; S2-3: When the trigger point is point C, record the data at point C, delete the data for point A recorded in S1-1, and proceed to S4; S3, when the laser emitting module (2) detects a trigger, it determines the trigger point; S3-1, When the trigger point is point C, record the data at point C, end the detection, and calculate the result; S3-2, When the trigger point is point A or point B, clear the current detection record and return to step S3; S4, when the laser emitting module (2) detects a trigger, it determines the trigger point; S4-1, When the trigger point is point B, record the data of point B and proceed to step S5; S4-2, When the trigger point is point A, record the data of point A, delete the data of point C in step S1-3 or step S2-3, and return to step S2; S4-3, When the trigger point is point C, delete the current detection record and return to step S4; S5, when the laser emitting module (2) detects a trigger, it determines the trigger point; S5-1: When the trigger point is point A, record the data at point A, end the detection, and calculate the result; S5-2, When the trigger point is point B or point C, delete the current detection record and return to step S5.

2. The method for detecting vehicle speed and acceleration according to claim 1, characterized in that, The time interval between adjacent steps in the detection method is less than or equal to 1 second.

3. The method for detecting vehicle speed and acceleration according to claim 1, characterized in that, The host (1) and the reflector (4) are respectively mounted on the same plane via the base.

4. The method for detecting vehicle speed and acceleration according to claim 1, characterized in that, The laser emitting module at point A (2a), laser emitting module at point B (2b), and laser emitting module at point C (2c) are all used to emit laser beams outward.

5. The method for detecting vehicle speed and acceleration according to claim 1, characterized in that, The reflector surface (3) of the reflector (4) is set perpendicular to the direction in which each laser emitting module emits a laser beam.

6. The method for detecting vehicle speed and acceleration according to claim 1, characterized in that, The reflector (4) has multiple areas on its surface that can receive laser beams.

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