CN114910660A

CN114910660A - Device and method for measuring speed and acceleration

Info

Publication number: CN114910660A
Application number: CN202210464478.4A
Authority: CN
Inventors: 吴凯扬; 詹强; 左昌余
Original assignee: Anhui Qingyu Photoelectric Technology Co ltd
Current assignee: Anhui Qingyu Photoelectric Technology Co ltd
Priority date: 2022-04-29
Filing date: 2022-04-29
Publication date: 2022-08-16

Abstract

The invention discloses a device and a method for measuring speed and acceleration, and belongs to the technical field of running acceleration measurement. The measuring device comprises a main machine part and an auxiliary machine part, wherein the main machine part and the auxiliary machine part are respectively arranged on two sides of a region to be measured, the main machine part comprises a main machine and a photosensitive element arranged in the main machine, the auxiliary machine part comprises an auxiliary machine and at least two laser emitters arranged in the auxiliary machine, a light path conducting assembly is arranged in the main machine, the light path conducting assembly comprises a reflector and a semi-reflecting and semi-transparent mirror, one laser beam is reflected to a reflecting surface of the semi-reflecting and semi-transparent mirror through the reflector, the other laser beam directly penetrates through the semi-transparent mirror of the semi-reflecting and semi-transparent mirror, and the two laser beams finally irradiate the same photosensitive element. The technical scheme of the invention is that through a special light path design, all laser changes are sensed by a photosensitive element, so that the time difference of light change in different light paths can be accurately recorded, and an accurate calculation result is obtained.

Description

Device and method for measuring speed and acceleration

Technical Field

The invention belongs to the technical field of running acceleration measurement, and particularly relates to a device and a method for measuring speed acceleration.

Background

Currently, for road traffic safety, it is necessary to measure the speed and acceleration of a vehicle traveling, i.e., to measure the traveling speed and acceleration of a traveling vehicle at a specified road monitoring point. The common vehicle speed and accelerometer use infrared or radar measurement techniques, which are expensive, generally heavy, require manual alignment, and are not self-measuring.

Through retrieval, the application with the Chinese patent application number of 201320122735.2 discloses a vehicle speed and acceleration measuring instrument, the measuring instrument in the application comprises two sets of induction measuring devices and a set of handheld measuring device, the induction measuring devices comprise three first shells which are sequentially and movably connected, wherein an infrared inductor is arranged on one side panel of each first shell, and the three infrared inductors and a first wireless information transmission module are connected with a first single chip microcomputer; the handheld measuring device comprises a second shell, a second single chip microcomputer and a second wireless signal transmission module are installed in the second shell, the measuring instrument senses a vehicle through an infrared sensor, acceleration is calculated through the speed of three sensors, the system is slow in response, and measuring accuracy is not accurate enough.

For another example, chinese patent application No. 202011404404.9 discloses a system for measuring the speed and acceleration of a motor vehicle based on photoelectric detection, in which a receiving device receives laser light emitted from an emitting device to form a light path. Then, the passing vehicle is captured through the on-off signal of the light path, the on-off of the light signal of the light path is converted into an electric signal, the electric control system of the receiving device can record the connection time and the disconnection time of each light path, and the speed and the acceleration of the vehicle are calculated according to the distance between the left speed laser transmitter and the right speed laser transmitter, the length of the vehicle, the connection time and the disconnection time. Two paths of emitters and two paths of photoelectric detectors are adopted for detection in the application, and the measurement precision still cannot be guaranteed.

Disclosure of Invention

1. Problems to be solved

The invention provides a device and a method for measuring speed and acceleration, aiming at the problems mentioned above, the technical scheme of the invention is that all laser changes are sensed by a photosensitive element through a special light path design, so that the time difference of light changes in different light paths can be accurately recorded, and an accurate calculation result is obtained.

2. Technical scheme

In order to solve the problems, the technical scheme adopted by the invention is as follows:

the invention discloses a device for measuring speed and acceleration, which comprises a main machine part and an auxiliary machine part, wherein the main machine part and the auxiliary machine part are respectively arranged at two sides of a region to be measured, the main machine part comprises a main machine and a photosensitive element arranged in the main machine, the auxiliary machine part comprises an auxiliary machine and at least two laser transmitters arranged in the auxiliary machine, a light path conduction assembly is also arranged in the main machine, and after laser emitted by the laser transmitters is conducted by the light path conduction assembly, multiple paths of laser are concentrated on the same photosensitive element.

Further, light path conduction subassembly include speculum and half reflection and half mirror, half reflection and half mirror is located the place ahead at photosensitive element, laser emitter be two ways, laser is reflected to the plane of reflection of half reflection and half mirror through the speculum all the way, another way directly passes the half mirror of half reflection and half mirror, two ways laser all shine on same photosensitive element finally.

Further, the optical path conduction assembly further comprises an adjusting bracket, the adjusting bracket comprises a base and an adjusting frame, the adjusting frame is provided with an inclined installation surface, and the reflector and the semi-reflecting and semi-transmitting mirror are fixed on the inclined installation surface.

Furthermore, a convex lens is arranged between the semi-reflecting and semi-transparent mirror and the photosensitive element.

Furthermore, a calibration piece is arranged between the reflector and the semi-reflecting and semi-transmitting mirror, and a calibration hole for reflected light to pass through is formed in the calibration piece.

Further, the host computer still include host computer dustcoat, host computer baffle and first mount pad, wherein, processing has the logical unthreaded hole that supplies the light to get into on the host computer baffle, photosensitive element sets up on first mount pad.

Further, the length of the light through hole is 9-11mm, the width of the light through hole is 1-3mm, and the length of the light through hole is formed along the long edge perpendicular to the host machine baffle.

Furthermore, the auxiliary machine further comprises an auxiliary machine outer cover and an auxiliary machine baffle, the auxiliary machine outer cover is fixed on the auxiliary machine truss through a fastener, and the laser emitter is fixed in the auxiliary machine through a second mounting seat.

The invention also provides a measuring method of the speed and the acceleration, which utilizes the measuring device to measure and comprises the following steps,

s1, when the vehicle enters the test area and blocks the first beam of light, the first timer and the second timer start timing;

s2, when the vehicle shields the two paths of light, the first timer finishes timing, and the third timer starts timing;

s3, when the vehicle releases the first beam of light, the second timer finishes timing, and the fourth timer starts timing;

s4, when the vehicle completely leaves the test area, the third timer and the fourth timer are both timed to be finished;

s5, the time values of the first timer, the second timer, the third timer and the fourth timer are t1, t2, t3 and t4 respectively, the speed v and the acceleration a are obtained through calculation,

wherein L is the distance between the two beams of laser light.

Further, the acceleration

Wherein, T1 ═ T1+ tsu 1; t2 ═ T2+ tsu1+ tsu 2; t3 ═ T3+ tsu2+ tsu 3; tsu1, tsu2, tsu3 are times of the process of variation in the amplitude value of the sensor output level per time period.

3. Advantageous effects

Compared with the prior art, the invention has the beneficial effects that:

(1) according to the device for measuring the speed and the acceleration, the light path conducting component is arranged in the host, multiple paths of laser are concentrated on the same photosensitive element after the laser emitted by the laser emitter is conducted by the light path conducting component, and compared with the traditional method that each path of laser changes is sensed by one photosensitive element, the design enables the time difference of light changes of different light paths to be accurately recorded, so that an accurate calculation result is obtained;

(2) according to the measuring device for the speed and the acceleration, the specific structure of the light path conducting assembly is further optimized, the light path conducting assembly comprises the reflecting mirror and the semi-reflecting and semi-transmitting mirror, two paths of laser emitted by the laser emitter are reflected to the reflecting surface of the semi-reflecting and semi-transmitting mirror, the other path of laser directly penetrates through the semi-transmitting mirror of the semi-reflecting and semi-transmitting mirror, and the two paths of laser finally irradiate onto the same photosensitive element; in addition, a convex lens is arranged between the semi-reflecting and semi-transparent mirror and the photosensitive element, and the arrangement of the convex lens can ensure that the two laser beams finally irradiate the photosensitive element with one beam of light so as to enhance the intensity of the irradiating light;

(3) according to the measuring device for the speed and the acceleration, the calibration piece is arranged between the reflector and the semi-reflecting and semi-transmitting mirror, the calibration piece is provided with the calibration hole for reflected light to pass through, if the light passes through the calibration hole, the light path is correct, if the light hits a solid structure around the calibration hole, the light path is deviated, and at the moment, the calibration hole is used as a target and is matched with the adjusting bracket, so that the angle of the reflector is conveniently adjusted;

(4) according to the device for measuring the speed and the acceleration, the main machine and the auxiliary machine are respectively composed of the outer cover and the baffle plate, a sealed environment is formed, all the parts are located in the sealed inner cavity, the ambient light interference and dust and rainwater pollution can be effectively prevented, the measurement precision is guaranteed, and meanwhile the service lives of all the parts are prolonged.

Drawings

FIG. 1 is a schematic structural diagram of a velocity and acceleration measuring device according to the present invention;

FIG. 2 is a schematic diagram of a main body of the measuring device of the present invention;

FIG. 3 is a schematic diagram of an auxiliary machine of the measuring device of the present invention;

FIG. 4 is a schematic diagram of the measuring device of the present invention for measuring the running speed and acceleration of the vehicle;

FIG. 5 is a state transition diagram of the light path blocking situation in the method for measuring velocity and acceleration according to the present invention;

FIG. 6 is a time chart of the process of changing the amplitude value of the sensor output level in the present invention.

In the figure: 1. a host portion; 11. a host truss; 12. a host; 121. a host housing; 122. a host baffle plate; 1221. a light through hole; 123. a first mounting seat;

131. a mirror; 132. a half-reflecting and half-transmitting mirror; 133. a convex lens; 134. adjusting the bracket; 1341. a base; 1342. an adjusting frame; 135. a calibration piece; 14. a photosensitive element;

2. an auxiliary machine section; 21. an auxiliary machine truss; 22. a laser transmitter; 23. a second mounting seat;

24. an auxiliary machine; 241. an auxiliary machine outer cover; 242. an auxiliary machine baffle;

3. a fastener.

Detailed Description

The invention is further described with reference to specific examples.

Example 1

As shown in fig. 1, the device for measuring speed and acceleration of the present embodiment includes a main machine portion 1 and an auxiliary machine portion 2, the main machine portion 1 and the auxiliary machine portion 2 are respectively disposed at two sides of a region to be measured, wherein the main machine portion 1 includes a main machine 12 and a photosensitive element 14 disposed in the main machine 12, the auxiliary machine portion 2 includes an auxiliary machine 24 and at least two laser emitters 22 disposed in the auxiliary machine 24, a light path conducting assembly is further disposed in the main machine 12, and after laser emitted by the laser emitters 22 is conducted by the light path conducting assembly, multiple paths of laser are concentrated on the same photosensitive element 14. Compared with the traditional method, each path of laser change is sensed by a photosensitive element, and the design enables the time difference of light changes of different paths to be accurately recorded, so that an accurate calculation result is obtained.

As shown in fig. 2, the host 12 further includes a host housing 121, a host baffle 122 and a first mounting seat 123, wherein the host housing 121 is mounted on the host truss 11 by a fastener 3, a light hole 1221 for light to enter is formed in the host baffle 122, and the photosensitive element 14 is disposed on the first mounting seat 123. In order to prevent the interference of ambient light, light can enter the inside of the host except the light through hole 1221, and other parts cannot transmit light.

Since the light emitted from the laser spreads with the distance and the light spot spreads to a light spot, which affects the light blocking effect when the vehicle passes through the light path, the size of the light hole 1221 in the horizontal direction should be as narrow as possible. However, the excessively narrow light-passing hole 1221 may cause a decrease in the amount of light entering, so that the light-sensing element 14 operates in a non-linear region, and thus the change in the amount of light entering may cause an insignificant change in the electrical signal. The clear aperture 1221 is therefore selected to have a length (perpendicular to the long side of the host baffle 122 in FIG. 2) of 9-11mm and a width (parallel to the long side of the host baffle 122 in FIG. 2) of 1-3 mm.

The parameters of the light-passing hole 1221 are selected and mainly considered based on two factors of vehicle speed and laser diffusion angle of the laser. In the embodiment, the application scene is mainly urban roads, and the use scenes from one lane road to three lane roads are possible. When the laser emits laser, the light beam can be diffused outward at a certain angle, so that the light through hole 1221 is enlarged in the direction perpendicular to the driving direction to ensure the light entering amount, and the diffused light spot can enter the light through hole with the least interference of ambient light. According to the experiment, 10mm was selected as the vertical parameter of the clear hole 1221. Since enlarging the light inlet in the horizontal direction of the vehicle would lead to a longer shading process (theoretically should be instantaneous shading), 2mm was chosen as the horizontal parameter of the light inlet. In addition, the parameter of the light-passing hole 1221 is selected according to the time required for the light-sensing element 14 to change the level after the light change, i.e., tsu value, which is not more than 5 ms. The width of the clear aperture 1221 also affects the magnitude of the actual change time of the level, that is, tsu _1, and when the clear aperture 1221 is too wide, the time of the intensity change of the blocking light when the vehicle passes through is lengthened, and if the width of the clear aperture 1221 is h and the vehicle speed is v, tsu _1 is h/v. To ensure that the results are relatively accurate, it is then necessary to ensure that tsu _1< tsu. If the vehicle shields the light path with 1.4km/h, the shielding time is just 5ms, and the normal vehicle speed is far beyond 1.4km/h, so that the accuracy can be ensured not to be influenced.

As shown in fig. 3, the auxiliary machine 24 further includes an auxiliary machine housing 241 and an auxiliary machine baffle 242, the auxiliary machine housing 241 is fixed to the auxiliary machine truss 21 by the fastener 3, and the laser emitter 22 is fixed in the auxiliary machine 24 by the second mounting base 23. The light that two laser emitter 22 sent should keep the parallelism, and in this embodiment, the preferred fastening bolt that has of fastener 3, host computer 12 and auxiliary engine 24 all have dustcoat and baffle to constitute, form sealed environment, and each part is located this sealed inner chamber, can effectively prevent ambient light interference and dust rainwater pollution, guarantees measurement accuracy, simultaneously, prolongs the life of each part.

As shown in fig. 1, the optical path conducting assembly includes a reflector 131 and a half-reflecting and half-transmitting mirror 132, wherein the reflector 131 and the half-reflecting and half-transmitting mirror 132 are horizontally distributed, and the half-reflecting and half-transmitting mirror 132 is located right in front of the photosensitive element 14, the laser emitter 22 in this embodiment is two paths, one path of laser light is reflected to the reflecting surface of the half-reflecting and half-transmitting mirror 132 through the reflector 131, the other path of laser light directly passes through the half-transmitting mirror of the half-reflecting and half-transmitting mirror 132, and the two paths of laser light finally irradiate the same photosensitive element 14.

The optical path conducting assembly further comprises an adjusting bracket 134, and the adjusting bracket 134 comprises a base 1341 and an adjusting bracket 1342, wherein the adjusting bracket 1342 has an inclined mounting surface, the inclination angle is preferably 45 °, and the reflector 131 and the half-reflecting and half-transmitting mirror 132 are both fixed on the inclined mounting surface. The adjusting bracket 134 is mainly used for fine-tuning the intensity of the light entering the sensor, keeping the light intensity of the single light approximately the same, and controlling the combined light intensity to be within the linear range of the photoelectric conversion function of the sensor.

A convex lens 133 is arranged between the half-reflecting and half-transmitting mirror 132 and the photosensitive element 14, the convex lens 133 is also arranged on the first mounting seat 123, and light reaches the photosensitive element 14 through a through hole of the first mounting seat 123 after reaching the convex lens 133. Inside two bundles of light got into host computer 12 via logical unthreaded hole 1221, reached the plane of reflection of semi-reflecting semi-transparent mirror 132 all the way via the reflection of speculum 131, made up into a bundle of light with the light of the lens face of other all the way through semi-reflecting semi-transparent mirror 132, through the focus of convex lens 133, gathered together dispersed light, made two bundles of light assemble into a light spot and shine on the sensor, finally shine and convert the signal of telecommunication into on photosensitive element.

When the half-reflecting and half-transmitting mirror 132 receives the light reflected by the reflector 131, in order to adjust the light easily, a calibration piece 135 is provided between the reflector 131 and the half-reflecting and half-transmitting mirror 132, and a calibration hole for the reflected light to pass through is provided on the calibration piece 135 as a target. At this time, the angle of the reflector 131 is finely adjusted only by adjusting the bracket 134 so that the reflected light passes through the calibration hole again, and the calibration is completed.

Example 2

In the method for measuring the speed and the acceleration of the embodiment, the measuring device in embodiment 1 is used for measuring, and the specific measuring steps are as shown in fig. 4, when a vehicle enters a test area and blocks a first beam of light (position 1), a first timer and a second timer start to time; when the vehicle shields the two paths of light rays (position 2), the first timer finishes timing, and the third timer starts timing; when the vehicle releases the first beam of light (position 3), the second timer finishes timing, and the fourth timer starts timing; when the vehicle completely leaves the test area (position 4), the third timer and the fourth timer are counted to be over. According to t1, t2, t3 and t4 and the width of the test area (i.e. the distance L between two laser beams), wherein t1, t2, t3 and t4 are the timing time values of the first timer, the second timer, the third timer and the fourth timer, respectively, so that the speed v and the acceleration a can be obtained. The formula is as follows:

in this embodiment, in the data acquisition process, three fixed parameters are set: timeout time, threshold 1, threshold 2. The overtime time can be obtained by calculation according to the maximum speed of the vehicle and the distance between two paths of parallel light rays, the threshold value 1 is a preset light intensity sampling value under the condition of single-path illumination, and the threshold value 2 is a preset light intensity sampling value under the condition of no illumination. In a specific determination process, as shown in fig. 5, after power is turned on, the situation that both of the two paths of light are released (i.e., both of the two paths of light irradiate the photosensitive element) is defaulted, at this time, if a sampling value is smaller than a threshold value 1, it is determined that one of the two paths of light are blocked, and if the sampling value is smaller than a threshold value 2, it is determined that both of the two paths of light are blocked. After the execution is completed in this order, three time signals t1, t2, t3 and a data valid signal sp _ valid are output. If the time kept in a certain state in the shielding process exceeds the set time, the acquired data is invalid, and the initial state is returned.

However, in the actual working process, a certain time tsu is required in the process of changing the output level amplitude value of the sensor, as shown in fig. 6, the waveform is captured by an oscilloscope of the data acquisition result, and the time of the process of changing the output level amplitude value of the sensor in each time period can be obtained and is respectively recorded as tsu1, tsu2 and tsu 3; according to the change time tsu1, tsu2 and tsu3 shown by the oscilloscope, the change time is less than 5ms, the change time difference is small and is relatively fixed, so that the time precision of each stage is improved, and the precision of the calculation result is improved. Specifically, the actual acceleration is calculated by the formula,

wherein, T1 is T1+ tsu 1; t2 ═ T2+ tsu1+ tsu 2; t3 ═ T3+ tsu2+ tsu 3; as can be seen from the above formula, the value of tsu is exponentially amplified and ultimately severely affects the calculation result of the acceleration.

When multichannel laser measures the speed acceleration among traditional remote sensing equipment, every way laser adopts the sheltering from and the release of a photosensitive original paper response laser, and the characteristic curve of different photosensitive original papers when to the light spot conversion is different. Therefore, even at the same time, the change time of the same electrical signal generated by different photosensitive elements receiving the same light change is different, so the time of the light change measured in this way is inaccurate, and the calculated velocity and acceleration values are also inaccurate, especially for the acceleration, the time error is exponentially amplified in the formula. The invention makes all the changes of the laser sensed by a photosensitive element through a special light path design, thus the time difference of the light changes in different light paths can be accurately recorded, and an accurate calculation result is obtained.

The present invention and its embodiments have been described above schematically, without limitation, and what is shown in the drawings is only one of the embodiments of the present invention, and the actual structure is not limited thereto. Therefore, if the person skilled in the art receives the teaching, without departing from the spirit of the invention, the person skilled in the art shall not inventively design the similar structural modes and embodiments to the technical solution, but shall fall within the scope of the invention.

Claims

1. A measuring device of speed and acceleration comprises a main machine part (1) and an auxiliary machine part (2), wherein the main machine part (1) and the auxiliary machine part (2) are respectively arranged at two sides of a region to be measured, and the measuring device is characterized in that: the main machine part (1) comprises a main machine (12) and a photosensitive element (14) arranged in the main machine (12), the auxiliary machine part (2) comprises an auxiliary machine (24) and at least two laser transmitters (22) arranged in the auxiliary machine (24), wherein a light path conduction assembly is further arranged in the main machine (12), and after laser emitted by the laser transmitters (22) is conducted by the light path conduction assembly, multiple paths of laser are concentrated on the same photosensitive element (14).

2. A velocity and acceleration measuring apparatus according to claim 1, wherein: light path conduction subassembly include speculum (131) and half reflection semi-transparent mirror (132), half reflection semi-transparent mirror (132) are located the place ahead of photosensitive element (14), laser emitter (22) be two ways, laser of the same way reflects the plane of reflection to half reflection semi-transparent mirror (132) through speculum (131), another way directly passes the semi-transparent mirror of half reflection semi-transparent mirror (132), two way laser are finally all shone on same photosensitive element (14).

3. A velocity and acceleration measuring apparatus according to claim 2, wherein: the optical path conduction assembly further comprises an adjusting bracket (134), wherein the adjusting bracket (134) comprises a base (1341) and an adjusting bracket (1342), the adjusting bracket (1342) is provided with an inclined mounting surface, and the reflector (131) and the semi-reflecting and semi-transmitting mirror (132) are fixed on the inclined mounting surface.

4. A velocity and acceleration measuring apparatus according to claim 3, wherein: and a convex lens (133) is arranged between the semi-reflecting and semi-transparent mirror (132) and the photosensitive element (14).

5. The apparatus for measuring velocity and acceleration according to claim 4, wherein: a calibration piece (135) is arranged between the reflector (131) and the semi-reflecting and semi-transmitting mirror (132), and a calibration hole for reflected light to pass through is formed in the calibration piece (135).

6. A velocity and acceleration measuring apparatus according to any one of claims 1 to 5, characterized in that: the host (12) further comprises a host outer cover (121), a host baffle (122) and a first mounting seat (123), wherein a light through hole (1221) for light to enter is processed on the host baffle (122), and the photosensitive element (14) is arranged on the first mounting seat (123).

7. A device for measuring velocity and acceleration according to claim 6, characterized in that: the length of the light through hole (1221) is 9-11mm, the width of the light through hole is 1-3mm, and the length of the light through hole (1221) is arranged along the long side perpendicular to the host machine baffle plate (122).

8. A velocity and acceleration measuring apparatus according to claim 7, wherein: the auxiliary machine (24) further comprises an auxiliary machine outer cover (241) and an auxiliary machine baffle (242), the auxiliary machine outer cover (241) is fixed on the auxiliary machine truss (21) through a fastener (3), and the laser emitter (22) is fixed in the auxiliary machine (24) through a second mounting seat (23).

9. A method for measuring velocity and acceleration is characterized in that: the measurement is performed by using the measuring device of velocity and acceleration according to any one of claims 1 to 8,

s1, when the vehicle enters the test area and shields the first beam of light, the first timer and the second timer start timing;

wherein L is the distance between the two beams of laser light.

10. A method of measuring velocity and acceleration according to claim 9, characterized in that: the acceleration

Wherein, T1 is T1+ tsu 1; t2 ═ T2+ tsu1+ tsu 2; t3 ═ T3+ tsu2+ tsu 3; tsu1, tsu2, tsu3 are times of the process of variation in the sensor output level amplitude value per time period.