Laser ranging anti-collision method

Abstract

The present invention discloses a laser ranging anti-collision method with strong anti-interference ability, which includes the steps of: A. During the movement of a vehicle or an object, the data acquisition control unit obtains the measured distance L between the vehicle and an obstacle; B. When the measured distance L < the set distance threshold, the data acquisition control unit simultaneously measures the number N of laser beams emitted and the number n of received reflection signals within a time interval △t; C. Calculate the intrusion rate within the time interval △t; c1. When the intrusion rate is less than the set intrusion rate threshold, the data acquisition control unit filters out false signals; c2. When the intrusion rate is greater than the set intrusion rate threshold, the data acquisition control unit issues an alarm signal and / or a control signal. When a vehicle or an object operates in a workshop or factory building filled with a large amount of dust or in a heavy rain and open-air environment, the laser ranging sensor emits laser signals. When the laser beams are interfered by dust or raindrops, it can judge and filter out false signals to avoid premature alarm, deceleration / steering, and braking / hovering.

Description

Technical Field

[0001] The present invention relates to the technical field of laser ranging, and particularly relates to a laser ranging anti-collision method for a vehicle or an object during movement. Background Art

[0002] Traditional ranging technologies are divided into unidirectional ranging technology and bidirectional ranging technology. The ranging method based on the time-of-flight principle belongs to bidirectional ranging technology, which mainly measures the distance between nodes by using the round-trip flight time between two asynchronous transceivers. The time-of-flight principle of laser is as follows: the laser emitter emits a laser pulse wave, and the internal timer starts to calculate the time t1. When the laser wave hits an object, part of the energy returns. When the laser receiver receives the returned laser, the internal timer t2 stops. The distance from the lidar to the object is: S = C×(t2 - t1) / 2, where C is the speed of light.

[0003] The patent document with the application number 201822207800.7 discloses an overhead crane anti-collision device based on a laser ranging sensor. The laser ranging sensor is installed on the main beam of the overhead crane body, and the laser reflector is installed on the side wall of the workshop building and the overhead crane body. The data acquisition control unit, the industrial all-in-one machine and the audible and visual alarm are all installed in the control room of the overhead crane body. During the process of the overhead crane traveling in the workshop, the laser ranging sensor emits a laser ranging signal. If another oncoming overhead crane or the side wall approaches in front of the overhead crane, the laser reflector installed on the overhead crane body or the side wall will reflect the laser signal back to the laser ranging sensor. After the laser ranging sensor receives the reflected laser signal, it transmits the received reflected laser signal to the data acquisition control unit. The data acquisition control unit calculates the distance between two adjacent overhead crane bodies or between the overhead crane and the side wall according to the time difference between the laser emission time and the reception time. When the distance < safety distance, the data acquisition control unit will prompt an alarm on the industrial all-in-one machine, and at the same time, it will also warn the driver of the overhead crane through the audible and visual alarm to brake urgently to avoid collision.

[0004] The patent document with the application number 202021261972.3 discloses a biaxial scanning 3D lidar. The reflector adopts a regular frustum structure. By rotating the reflector, the effect of 3D scanning is achieved, and distance measurement in multiple directions and at multiple angles is realized. Since this patent can measure the distance between objects, it can also be applied to distance measurement alarm.

[0005] However, the above patent has the following technical problems: When producing in workshop factories with harsh production environments, such as steelmaking workshops, a large amount of dust fills the workshop factory building. When the laser ranging sensor emits a laser signal, the laser beam is easily interfered by the dust, that is, the laser beam hits the dust particles and is reflected back to the laser ranging sensor. The laser ranging sensor receives this signal and generates a misjudgment, triggering an early alarm. In open-air conditions, such as in heavy rain, haze, or foggy weather, false alarm misjudgments are also likely to occur. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a laser ranging anti-collision method with strong anti-interference ability.

[0007] The technical solution adopted by the present invention to solve its technical problem is: A laser ranging anti-collision method, including the steps:

[0008] A. During the movement of the vehicle or object, the laser light source module continuously emits pulsed laser beams at a frequency. The laser beam is reflected by an obstacle and then passes through a focusing lens and is received by a receiving plate. The data acquisition and control unit obtains the measured distance L between the vehicle and the obstacle.

[0009] B. When the measured distance L from the obstacle < the set distance threshold, the data acquisition and control unit simultaneously measures the number N of laser beams emitted and the number n of received reflected signals within a time period of △t.

[0010] C. Calculate the effective intrusion rate within the time period of △t = the number n of received reflected signals / the number N of laser beams emitted.

[0011] c1. When the effective intrusion rate < the set effective intrusion rate threshold, the data acquisition and control unit filters out false signals.

[0012] c2. When the effective intrusion rate > the set effective intrusion rate threshold, the data acquisition and control unit issues an alarm signal and / or a control signal.

[0013] Further, it further includes step D. When the measured distance L from the obstacle < the set distance threshold, the data acquisition and control unit starts timing simultaneously and forms a continuous trigger threshold time t.

[0014] The trigger threshold time t is the sum of several △t.

[0015] When several effective intrusion rates within the trigger threshold time t are all greater than the set effective intrusion rate threshold, the data acquisition and control unit issues an alarm signal and / or a control signal.

[0016] Further, the set distance thresholds in step B include a first alarm distance threshold L1, a deceleration distance threshold L2, and a braking stop distance threshold L3, and the first alarm distance threshold L1 ≥ deceleration distance threshold L2 > braking stop distance threshold L3.

[0017] Further, the first alarm distance threshold L1 > deceleration distance threshold L2.

[0018] Further, the data acquisition control unit is respectively connected to an alarm device, a braking device, and a driving device through a PLC.

[0019] Further, within the trigger threshold time t, when the first alarm distance threshold L1 > measured distance L ≥ deceleration distance threshold L2, and several effective intrusion rates are all greater than the effective intrusion rate threshold, the data acquisition control unit controls the alarm device to give an alarm;

[0020] Within the trigger threshold time t, when the deceleration distance threshold L2 > measured distance L ≥ braking stop distance threshold L3, and several effective intrusion rates are all greater than the effective intrusion rate threshold, the data acquisition control unit controls the braking device or the driving device to decelerate;

[0021] Within the trigger threshold time t, when the measured distance L < braking stop distance threshold L3, and several effective intrusion rates are all greater than the effective intrusion rate threshold, the data acquisition control unit controls the braking device to brake to a stop.

[0022] Further, the set distance thresholds in step B include a second alarm distance threshold L4, a turning distance threshold L5, and a hovering distance threshold L6, and the second alarm distance threshold L4 ≥ turning distance threshold L5 > hovering distance threshold L6.

[0023] Further, the second alarm distance threshold L4 > turning distance threshold L5.

[0024] Further, the second alarm distance threshold L4 includes a front alarm distance threshold L4A, a rear alarm distance threshold L4C, and a side and up - down alarm distance threshold L4B, and the front alarm distance threshold L4A > side and up - down alarm distance threshold L4B > rear alarm distance threshold L4C;

[0025] The turning distance threshold L5 includes a front turning distance threshold L5A, a rear turning distance threshold L5C, and a side and up - down turning distance threshold L5B, and the front turning distance threshold L5A > side and up - down turning distance threshold L5B > rear turning distance threshold L5C;

[0026] The hovering distance threshold L6 includes a front hovering distance threshold L6A, a rear hovering distance threshold L6C, and a side and vertical hovering distance threshold L6B, where the front hovering distance threshold L6A > the side and vertical hovering distance threshold L6B > the rear hovering distance threshold L6C.

[0027] Furthermore, the data acquisition control unit is respectively connected to an alarm device, a steering device, and a driving device through a control module.

[0028] Furthermore, within the trigger threshold time t, when the second alarm distance threshold L4 > the measured distance L ≥ the steering distance threshold L5, and several effective intrusion rates are all greater than the effective intrusion rate threshold, the data acquisition control unit controls the alarm device to give an alarm;

[0029] Within the trigger threshold time t, when the steering distance threshold L5 > the measured distance L ≥ the hovering distance threshold L6, and several effective intrusion rates are all greater than the effective intrusion rate threshold, the data acquisition control unit controls the steering device to steer;

[0030] Within the trigger threshold time t, when the measured distance L < the hovering distance threshold L6, and several effective intrusion rates are all greater than the effective intrusion rate threshold, the data acquisition control unit controls the driving device to hover.

[0031] Furthermore, the effective intrusion rate threshold is 30% - 70%.

[0032] Furthermore, the effective intrusion rate threshold is divided into an indoor effective intrusion rate threshold and an outdoor effective intrusion rate threshold;

[0033] The indoor effective intrusion rate threshold is 30% - 50%, and the outdoor effective intrusion rate threshold is 40% - 70%.

[0034] Furthermore, the △t is 100 ms or 120 ms.

[0035] Furthermore, the trigger threshold time t is 100 - 3000 ms.

[0036] Furthermore, the laser light source module, the focusing lens, and the receiving plate form a laser ranging sensor, and the laser ranging sensor is installed on a rotating device to achieve rotational scanning.

[0037] Compared with the prior art, the beneficial effects of the present invention are as follows: The present invention provides a laser ranging anti-collision method with strong anti-interference ability. When a vehicle or an object operates in a workshop or factory building filled with a large amount of dust or in a heavy rain and open-air environment, the laser ranging sensor emits a laser signal. When the laser beam is interfered by dust or raindrops, it can judge and filter out false signals, avoiding premature alarms, deceleration / steering, and braking / hovering. It ensures the accurate emission of alarm signals and control signals, and has strong anti-interference ability. Brief Description of the Drawings

[0038] Figure 1 is a schematic structural diagram of the laser ranging sensor of the present invention;

[0039] Figure 2 is a control flow chart of the present invention applied to a vehicle;

[0040] Figure 3 is a control flow chart of the present invention applied to a drone;

[0041] Reference Numerals: 1 - Laser light source module; 2 - Focusing lens; 3 - Receiving plate; 4 - Vehicle body; 5 - Obstacle; 6 - Rotating device; 10 - Laser ranging sensor. Detailed Description of the Invention

[0042] The present invention will be further described below with reference to the drawings and embodiments.

[0043] As shown in the Figure 1 drawing, due to the particularity of the vehicle operation, it runs in a straight line. Therefore, a laser ranging sensor 10 is installed on the vehicle body 4. The laser ranging sensor 10 integrally includes a laser light source module 1, a focusing lens 2, a receiving plate 3, etc. The laser light source module 1 includes a laser light source and a collimating lens. The laser beam emitted from the laser light source is emitted after passing through the collimating lens to form an emission beam. The reflected beam reflected back by the obstacle 5 is focused by the focusing lens 2 and converges on the receiving plate 3. Based on the time-of-flight ranging principle, the distance value between the vehicle and the obstacle 5 detected in real time is calculated through the time difference between the emission time of the laser light source and the reception time of the receiving plate 3. The data acquisition control unit can make a judgment according to the detected distance value. When the set conditions are met, the data acquisition control unit sends an alarm signal or a control signal. When applied to a vehicle, the control signal includes a deceleration signal and a braking stop signal. The deceleration signal is used to control the deceleration of the driving device or the braking deceleration of the braking device. The braking stop signal is used to control the braking stop of the braking device.

[0044] As shown in the Figure 1As shown, for the need to measure and monitor the running distance in the horizontal direction, such as the running of cars and trains, and the left and right directions during the running of a vehicle, in order to expand the scanning area in the horizontal plane or even perform a 360° all-round scan, a rotating device 6 is installed below the laser ranging sensor 10. The rotating device 6 is driven by a driving motor to rotate reciprocally at a certain angle or rotate 360°, thereby realizing horizontal two-dimensional scanning, detecting distances in different directions, and at the same time, different distance thresholds and effective intrusion rate thresholds can be set in different directions according to needs, and whether to issue an alarm and control signal is judged. Similarly, a 3D scanning lidar can also be used to perform all-round and multi-angle distance detection and realize alarm and control, which is more suitable for use in situations where the surrounding obstacles are complex or on drones with a large operating range. At this time, the control signal includes a steering signal and a hovering signal. The steering signal is used to control the steering device to adjust the flight direction of the drone. The hovering signal is used to control the driving device to make the drone hover in the air.

[0045] The laser ranging anti-collision method of the present invention includes the steps:

[0046] A, During the movement of the vehicle or object, the laser light source module 1 continuously emits pulsed laser beams at a frequency. The laser beams are reflected by the obstacle 5 and then received by the receiving plate 3 through the focusing lens 2 after reflection; the data acquisition and control unit obtains the measured distance L between the vehicle and the obstacle 5.

[0047] B, When the measured distance L from the obstacle 5 < the set distance threshold, the data acquisition and control unit simultaneously measures the number N of laser beams emitted and the number n of received reflected signals within the time Δt.

[0048] C, Calculate the effective intrusion rate within the time Δt = the number n of received reflected signals / the number N of laser beams emitted;

[0049] c1, When the effective intrusion rate < the set effective intrusion rate threshold, the data acquisition and control unit filters out false signals;

[0050] c2, When the effective intrusion rate > the set effective intrusion rate threshold, the data acquisition and control unit issues an alarm signal or a control signal.

[0051] When applied to a traveling crane, the data acquisition and control unit is respectively connected to an alarm device, a braking device, and a driving device through a PLC. The effective intrusion rate threshold can be set according to actual needs. The effective intrusion rate threshold is 30%-70%. In the above steps, the set distance thresholds include a first alarm distance threshold L1, a deceleration distance threshold L2, and a braking stop distance threshold L3, and the first alarm distance threshold L1≥deceleration distance threshold L2>braking stop distance threshold L3. When the first alarm distance threshold L1 = deceleration distance threshold L2, the data acquisition and control unit controls the alarm device to give an alarm through the PLC, and at the same time controls the traveling crane to decelerate through the PLC. Preferably, the first alarm distance threshold L1>deceleration distance threshold L2>braking stop distance threshold L3. When the measured distance L<first alarm distance threshold L1, it is necessary to prompt within the safe distance of the traveling crane, but when the distance is relatively far, an alarm prompt is first issued to remind people to pay attention. When the traveling crane enters the deceleration distance, that is, the measured distance L<deceleration distance threshold L2, the data acquisition and control unit controls the deceleration of the traveling crane through the PLC. During deceleration control, the PLC can either control the driving motor of the traveling crane to make the driving motor run at a reduced speed; or control the braking device to decelerate the traveling crane. When the traveling crane enters the braking stop distance, that is, the measured distance L<braking stop distance threshold L3, the data acquisition and control unit performs an emergency braking stop on the traveling crane through the PLC. During braking stop, the PLC only controls the braking device to achieve an emergency stop of the traveling crane.

[0052] During the experiment, the effective intrusion rate within one or more Δt time intervals is greater than the set effective intrusion rate, but the obstacle 5 measured ahead is still not real. In this case, the effective intrusion rate within at least one Δt time interval is less than the set effective intrusion rate, that is, the effective intrusion rate within all Δt time intervals is not greater than the set effective intrusion rate. The reason is that within the above-mentioned one or more Δt time intervals, the spatial arrangement of dust particles or raindrops causes more reflected light beams reflected back by the dust particles or raindrops, resulting in the effective intrusion rate within one or more of the above-mentioned Δt time intervals being greater than the set effective intrusion rate, rather than the effective intrusion rate within all Δt time intervals being greater than the set effective intrusion rate. To prevent the above situation from occurring and causing misjudgment. Therefore, the data acquisition control unit starts timing from the first pulse signal measured less than the distance threshold and forms a continuous trigger threshold time t, where the trigger threshold time t is the sum of several Δt. Within the trigger threshold time t, the data acquisition control unit filters out the situation where the effective intrusion rate within one or more Δt time intervals is greater than the set effective intrusion rate threshold, that is, the effective intrusion rate within at least one Δt time interval is less than the set effective intrusion rate. Only when several effective intrusion rates within the trigger threshold time t are all greater than the effective intrusion rate threshold can it be shown that the obstacle 5 is real. Combining with the comparison of the measured distance L and the set distance threshold, the data acquisition control unit issues an alarm signal and / or a control signal to ensure accurate judgment. The trigger threshold time t can be set according to needs, and the trigger threshold time t is 100 - 3000 ms.

[0053] To further expand the applicable scenarios of the present invention, preferably, the effective intrusion rate threshold is divided into an indoor effective intrusion rate threshold and an outdoor effective intrusion rate threshold; the indoor effective intrusion rate threshold is 30% - 50%, and the outdoor effective intrusion rate threshold is 40% - 70%. Among them, the indoor reflection threshold is correspondingly applicable to the indoor environment, and the outdoor reflection threshold is correspondingly applicable to the outdoor environment.

[0054] Embodiment 1:

[0055] The traveling vehicle body 4 is installed in a factory environment filled with a large amount of dust particles. The laser ranging sensor 10 is installed on the traveling vehicle body 4 and is preferably installed at the front end in the traveling direction V of the vehicle. The laser ranging sensor 10 is integrally provided with a laser light source module 1, a focusing lens 2, and a receiving plate 3. The signal received by the receiving plate 3 is processed by the data acquisition control unit, and the data acquisition control unit is respectively connected to an alarm device, a braking device, and a driving device. The alarm device includes one or a combination of a sound alarm and a light alarm. After the control signal of the data acquisition control unit passes through the PLC, it controls the driving device and the braking device of the vehicle to achieve deceleration and braking to a stop.

[0056] Step 1: During the operation of the vehicle, the laser light source module 1 continuously emits pulsed laser beams at a frequency of 1000 Hz. The laser beams are reflected by the obstacle 5 and then pass through the focusing lens 2 and are received by the receiving plate 3. The data acquisition and control unit obtains the measured distance L between the vehicle and the obstacle 5.

[0057] Step 2: The data acquisition and control unit compares the measured distance L with the set distance thresholds. The set distance thresholds include the first alarm distance threshold L1, the deceleration distance threshold L2, and the braking stop distance threshold L3. The first alarm distance threshold L1 = 10 m, the deceleration distance threshold L2 = 6 m, and the braking stop distance threshold L3 = 3 m.

[0058] When the measured distance L < the first alarm distance threshold L1, the data acquisition and control unit starts measuring from the first pulsed signal that is less than the first alarm distance threshold L1 and measures the number N of laser beams emitted and the number n of received reflected signals within a time interval of Δt = 100 ms.

[0059] Step 3: When the measured distance L between the vehicle and the obstacle 5 < the first alarm distance threshold L1, the data acquisition and control unit starts timing simultaneously and forms a continuous trigger threshold time t. The trigger threshold time t is the sum of several Δt. The several effective intrusion rates within the trigger threshold time t are respectively compared with the set indoor effective intrusion rate threshold. The trigger threshold time t is 500 ms, including 5 Δt time intervals.

[0060] Step 4: The data acquisition and control unit calculates the effective intrusion rate within the time interval of Δt = n / N (where n is the number of received reflected signals and N is the number of laser beams emitted), and compares the calculated effective intrusion rate with the set indoor effective intrusion rate threshold of 50%.

[0061] Since dust is distributed in a three-dimensional dot pattern in the air and there are gaps between any two adjacent dust particles. A small number of emitted light beams hit the dust particles, and a large number of emitted light beams pass through the gaps and shoot into the distance. The small number of emitted light beams hitting the dust particles undergo diffuse reflection on their outer surfaces, forming dust reflection beams. Most of the dust reflection beams are scattered in the air, and only a very small part of the dust reflection beams are received by the laser ranging sensor 10. The emitted light beams undergo diffuse reflection on the surface of obstacles 5 such as the vehicle ahead or the side wall. Most of the obstacle reflection beams are scattered in the air, and a small part of the obstacle reflection beams are received by the laser ranging sensor 10.

[0062] (1) Within the trigger threshold time t, when the first alarm distance threshold L1 > measured distance L ≥ deceleration distance threshold L2, that is: 10m > measured distance L ≥ 6m, and several effective intrusion rates are all greater than the set indoor effective intrusion rate threshold of 50%, the obstacle 5 measured in front is real, and the data acquisition control unit issues an alarm signal to prompt personnel to handle it; when any one or more of the effective intrusion rates are less than the set indoor effective intrusion rate threshold of 50%, the obstacle signal measured in front is a false signal, and the data acquisition control unit does not issue an alarm signal.

[0063] (2) Within the trigger threshold time t, when the deceleration distance threshold L2 > measured distance L ≥ braking stop distance threshold L3, that is: 6m > measured distance L ≥ 3m, and several effective intrusion rates are all greater than the set indoor effective intrusion rate threshold of 50%, the obstacle 5 measured in front is real, and the data acquisition control unit controls the vehicle to decelerate through the PLC; when any one or more of the effective intrusion rates are less than the set indoor effective intrusion rate threshold of 50%, the obstacle signal measured in front is a false signal, and the data acquisition control unit does not issue a deceleration signal.

[0064] (3) Within the trigger threshold time t, when the measured distance L < braking stop distance threshold L3, that is: measured distance L < 3m, and several effective intrusion rates are all greater than the set indoor effective intrusion rate threshold of 50%, the obstacle 5 measured in front is real, and the data acquisition control unit controls the braking device to brake and stop; when any one or more of the effective intrusion rates are less than the set indoor effective intrusion rate threshold of 50%, the obstacle signal measured in front is a false signal, and the data acquisition control unit does not issue a braking stop signal.

[0065] Embodiment 2:

[0066] The vehicle body 4 of the crane is installed in an open-air rainstorm environment. The laser ranging sensor 10 is installed on the vehicle body 4 of the crane, and is installed as far as possible at the front end in the running direction V of the crane. The laser ranging sensor 10 is integrally provided with a laser light source module 1, a focusing lens 2 and a receiving plate 3. The signal received by the receiving plate 3 is processed by the data acquisition control unit, and the data acquisition control unit is respectively connected with an alarm device, a braking device and a driving device. The alarm device includes one or a combination of a sound alarm and a light alarm. After the control signal of the control processor passes through the PLC, it controls the driving device and the braking device of the crane to achieve deceleration and braking to stop.

[0067] Step 1: During the running of the crane, the laser light source module 1 continuously emits pulsed laser beams at a frequency of 1000Hz. The laser beams are reflected by the obstacle 5 and then pass through the focusing lens 2, and the reflected signals are received by the receiving plate 3; the data acquisition control unit obtains the measured distance L between the crane and the obstacle 5.

[0068] Step 2: The data acquisition control unit compares the measured distance L with the set distance thresholds. The set distance thresholds include the first alarm distance threshold L1, the deceleration distance threshold L2, and the braking stop distance threshold L3. The first alarm distance threshold L1 = 10 m, the deceleration distance threshold L2 = 6 m, and the braking stop distance threshold L3 = 3 m.

[0069] When the measured distance L < the first alarm distance threshold L1, the data acquisition control unit starts measuring from the first pulse signal less than the first alarm distance threshold L1 and measures the number N of laser beams emitted and the number n of received reflected signals within a Δt time of 100 ms.

[0070] Step 3: When the measured distance L between the obstacle 5 is < the first alarm distance threshold L1, the data acquisition control unit starts timing simultaneously and forms a continuous trigger threshold time t; the trigger threshold time t is the sum of several Δt; several effective intrusion rates within the trigger threshold time t are respectively compared with the set outdoor effective intrusion rate threshold. The trigger threshold time t is 500 ms and includes 5 Δt times.

[0071] Step 4: The data acquisition control unit calculates the effective intrusion rate within the Δt time = the number n of received reflected signals / the number N of laser beams emitted and compares the calculated effective intrusion rate with the set outdoor effective intrusion rate threshold of 60%.

[0072] Since raindrops are densely distributed in the air and there are gaps between any two adjacent raindrops. A small number of emitted light beams hit the raindrops, and a large number of emitted light beams pass through the gaps and shoot into the distance. The small number of emitted light beams hitting the raindrops are diffusely reflected on their outer surfaces to form raindrop reflected light beams. Most of the raindrop reflected light beams are scattered in the air, and a very small part of the raindrop reflected light beams are received by the laser ranging sensor 10. The emitted light beams are diffusely reflected on the surface of obstacles 5 such as the vehicle in front or the side wall, most of the obstacle reflected light beams are scattered in the air, and a small part of the obstacle reflected light beams are received by the laser ranging sensor 10.

[0073] (1) Within the trigger threshold time t, when the first alarm distance threshold L1 > the measured distance L ≥ the deceleration distance threshold L2, that is: 10 m > the measured distance L ≥ 6 m, and several effective intrusion rates are all greater than the set outdoor effective intrusion rate threshold of 60%, the obstacle 5 measured in front is real, and the data acquisition control unit issues an alarm signal to prompt personnel to handle it; when any one or more of the effective intrusion rates are less than the set outdoor effective intrusion rate threshold of 60%, the obstacle signal measured in front is a false signal, and the data acquisition control unit does not issue an alarm signal.

[0074] (2) Within the trigger threshold time t, when the deceleration distance threshold L2 > measured distance L ≥ braking stop distance threshold L3, that is: 6m > measured distance L ≥ 3m, and several effective intrusion rates are all greater than the set outdoor effective intrusion rate threshold of 60%, the obstacle 5 measured in front is real, and the data acquisition control unit controls the vehicle to decelerate through the PLC; when any one or more of the effective intrusion rates are less than the set outdoor effective intrusion rate threshold of 60%, the obstacle signal measured in front is a false signal, and the data acquisition control unit does not send a deceleration signal.

[0075] (3) Within the trigger threshold time t, when the measured distance L < braking stop distance threshold L3, that is: measured distance L < 3m, and several effective intrusion rates are all greater than the set outdoor effective intrusion rate threshold of 60%, the obstacle 5 measured in front is real, and the data acquisition control unit controls the braking device to brake and stop; when any one or more of the effective intrusion rates are less than the set outdoor effective intrusion rate threshold of 60%, the obstacle signal measured in front is a false signal, and the data acquisition control unit does not send a braking stop signal.

[0076] When applied to an unmanned aerial vehicle (UAV), the data acquisition control unit is respectively connected to an alarm device, a steering device, and a driving device through a control module. The effective intrusion rate threshold can be set by itself according to actual needs. The said effective intrusion rate threshold is 30% - 70%. In the above steps, the set distance thresholds include a second alarm distance threshold L4, a steering distance threshold L5, and a hovering distance threshold L6, and the second alarm distance threshold L4 ≥ steering distance threshold L5 > hovering distance threshold L6. When the second alarm distance threshold L4 = steering distance threshold L5, the data acquisition control unit controls the alarm device to give an alarm through the control module, and at the same time controls the UAV to turn through the control module. Preferably, the second alarm distance threshold L4 > steering distance threshold L5 > hovering distance threshold L6. When the measured distance L < the second alarm distance threshold L4, it is necessary to prompt the safety distance of the UAV, but when the distance is relatively far, an alarm prompt is sent first to remind the personnel to pay attention. When the UAV enters the steering distance, that is, the measured distance L < the steering distance threshold L5, the data acquisition control unit controls the steering of the UAV through the control module. When steering, the control module controls the steering device. When the UAV enters the hovering distance, that is, the measured distance L < the hovering distance threshold L6, the data acquisition control unit controls the UAV to perform an emergency hover through the control module. When hovering, the control module controls the driving device.

[0077] Embodiment Three:

[0078] A laser ranging sensor for 3D detection is installed on the UAV body. The laser ranging sensor 10 is integrally provided with a laser light source module 1, a focusing lens 2, a receiving board 3 and a reflecting mirror with a regular prism structure. The signal received by the receiving board 3 is processed by the data acquisition control unit, and the data acquisition control unit is respectively connected with an alarm device, a driving device and a steering device through a control module. The alarm device includes one or a combination of a sound alarm and a light alarm provided on the UAV operation controller.

[0079] Step 1: During the flight of the UAV, the laser light source module 1 of the 3D lidar continuously emits pulsed laser beams at a frequency of 900 Hz. The laser beams are reflected by the reflecting mirror with a regular prism structure and then emitted. The reflecting mirror rotates to achieve scanning of the opposite side. The emitted light beam is reflected after passing through the obstacle 5 to form a reflected light beam. The reflected light beam is reflected by the reflecting mirror and focused by the focusing lens 2, and then the reflected signal is received by the receiving board 3; the data acquisition control unit obtains the measured distance L between the vehicle and the obstacle 5.

[0080] Step 2: The data acquisition control unit compares the measured distance L with the set distance threshold. Due to the operating speed of the UAV, the time requirement for a front collision is shorter. The values of the second alarm distance threshold L4 in different directions are different, including: the front alarm distance threshold L4A = 12 m, the side and up / down alarm distance threshold L4B = 5 m, and the rear alarm distance threshold L4C = 3 m. Set the steering distance threshold L5, including: the front steering distance threshold L5A = 4 m, the side and up / down steering distance threshold L5B = 2 m, and the rear steering distance threshold L5C = 1 m. Set the hovering distance threshold L6, including: the front hovering distance threshold L6A = 3 m, the side and up / down hovering distance threshold L6B = 1 m, and the rear hovering distance threshold L6C = 0.5 m.

[0081] When the measured distance L < the second alarm distance threshold L4 in the corresponding direction, the data acquisition control unit starts measuring from the first pulse signal whose measured distance is less than the second alarm distance threshold L4. Within a time △t of 120 ms, the number N of laser beams emitted and the number n of received reflected signals with a measured distance L < the corresponding set distance threshold are measured.

[0082] Step 3: When the measured distance L between the UAV and the obstacle 5 < the second alarm distance threshold L4 in the corresponding direction, the data acquisition control unit starts timing simultaneously and forms a continuous trigger threshold time t; the trigger threshold time t is the sum of several △t; several effective intrusion rates within the trigger threshold time t are respectively compared with the set outdoor effective intrusion rate threshold. The trigger threshold time t is 600 ms, including 5 △t times.

[0083] Step 4: The data acquisition control unit calculates the effective intrusion rate within the time period of △t = the number of received reflected signals n / the number of emitted laser beams N, and compares the calculated effective intrusion rate with the set outdoor effective intrusion rate threshold of 70%. At this time, different effective intrusion rate thresholds can also be set according to different directions.

[0084] (1) Within the trigger threshold time t, when the second alarm distance threshold L4 > the measured distance L ≥ the turning distance threshold L5, such as 12 m in front of the flight direction > the measured distance, and several effective intrusion rates are all greater than the set outdoor effective intrusion rate threshold of 70%, the obstacle 5 measured in front is real, and the data acquisition control unit issues an alarm signal to prompt personnel to handle it; when any one or more of the effective intrusion rates are less than the set outdoor effective intrusion rate threshold of 70%, the obstacle signal measured in front is a false signal, and the data acquisition control unit does not issue an alarm signal.

[0085] (2) Within the trigger threshold time t, when the turning distance threshold L5 > the measured distance L, such as 2 m on the side of the flight direction > the measured distance L, and several effective intrusion rates are all greater than the set outdoor effective intrusion rate threshold of 70%, the obstacle 5 measured in front is real, and the data acquisition control unit controls the UAV to change direction; when any one or more of the effective intrusion rates are less than the set outdoor effective intrusion rate threshold of 70%, the obstacle signal measured in front is a false signal, and the data acquisition control unit does not issue a turning signal.

[0086] (3) Within the trigger threshold time t, when the hovering distance threshold L6 > the measured distance L, such as 1 m on the side of the flight direction > the measured distance L, and several effective intrusion rates are all greater than the set outdoor effective intrusion rate threshold of 70%, the obstacle 5 measured in front is real, and the data acquisition control unit controls the UAV to hover; when any one or more of the effective intrusion rates are less than the set outdoor effective intrusion rate threshold of 70%, the obstacle signal measured in front is a false signal, and the data acquisition control unit does not issue a hovering signal.

[0087] The above is the specific implementation manner of the present invention. It can be seen from the implementation process that the present invention provides a laser ranging anti-collision method with strong anti-interference ability. When a vehicle or an object runs in a workshop or factory building filled with a large amount of dust or in a heavy rain and open-air environment, the laser ranging sensor emits a laser signal. When the laser beam is interfered by dust or raindrops, it can judge and filter false signals to avoid early alarm, deceleration / turning, and braking / hovering. Ensure accurate alarm signals and control signals are sent, with strong anti-interference ability.

Claims

1. Laser ranging anti-collision method, characterized in that: Including the steps: A. During the movement of the vehicle or object, the laser light source module (1) continuously emits pulsed laser beams at a frequency. After passing through the obstacle (5), the laser beams are reflected and pass through the focusing lens (2), and the reflected signals are received by the receiving plate (3). The data acquisition and control unit obtains the measured distance L between the vehicle and the obstacle (5). B. When the measured distance L between the vehicle and the obstacle (5) is less than the set distance threshold, the data acquisition and control unit simultaneously measures the number N of laser beams emitted and the number n of received reflected signals within a time interval Δt. C. Calculate the effective intrusion rate within the time interval Δt = number n of received reflected signals / number N of laser beams emitted. c1. When the effective intrusion rate is less than the set effective intrusion rate threshold, the data acquisition and control unit filters out false signals. c2. When the effective intrusion rate is greater than the set effective intrusion rate threshold, the data acquisition and control unit issues an alarm signal and / or a control signal. It further includes step D. When the measured distance L between the vehicle and the obstacle (5) is less than the set distance threshold, the data acquisition and control unit starts timing simultaneously and forms a continuous trigger threshold time t. The trigger threshold time t is the sum of several Δt. When several effective intrusion rates within the trigger threshold time t are all greater than the set effective intrusion rate threshold, the data acquisition and control unit issues an alarm signal and / or a control signal. The set distance threshold in step B includes a first alarm distance threshold L1, a deceleration distance threshold L2, and a braking stop distance threshold L3, and the first alarm distance threshold L1 ≥ deceleration distance threshold L2 > braking stop distance threshold L3.

2. The laser ranging and anti-collision method according to claim 1, wherein: The first alarm distance threshold L1 > deceleration distance threshold L2.

3. The laser ranging anti-collision method according to claim 2, wherein: The data acquisition and control unit is respectively connected to an alarm device, a braking device, and a driving device through a PLC.

4. The laser ranging anti-collision method according to claim 3, characterized in that: Within the trigger threshold time t, when the first alarm distance threshold L1 > measured distance L ≥ deceleration distance threshold L2, and several effective intrusion rates are all greater than the effective intrusion rate threshold, the data acquisition and control unit controls the alarm device to give an alarm. Within the trigger threshold time t, when the deceleration distance threshold L2 > measured distance L ≥ braking stop distance threshold L3, and several effective intrusion rates are all greater than the effective intrusion rate threshold, the data acquisition and control unit controls the braking device or the driving device to decelerate. Within the trigger threshold time t, when the measured distance L < braking stop distance threshold L3, and several effective intrusion rates are all greater than the effective intrusion rate threshold, the data acquisition and control unit controls the braking device to brake and stop.

5. The laser ranging and anti-collision method according to claim 1, characterized in that: The set distance threshold in step B includes a second alarm distance threshold L4, a steering distance threshold L5, and a hovering distance threshold L6, and the second alarm distance threshold L4 ≥ steering distance threshold L5 > hovering distance threshold L6.

6. The laser ranging anti-collision method according to claim 5, characterized in that: The second alarm distance threshold L4 > steering distance threshold L5.

7. The laser ranging and anti-collision method according to claim 5, wherein: The second alarm distance threshold L4 includes a front alarm distance threshold L4A, a rear alarm distance threshold L4C, and a side and vertical and horizontal alarm distance threshold L4B, and the front alarm distance threshold L4A > side and vertical and horizontal alarm distance threshold L4B > rear alarm distance threshold L4C; The steering distance threshold L5 includes a forward steering distance threshold L5A, a rear steering distance threshold L5C, and a side and vertical steering distance threshold L5B, where the forward steering distance threshold L5A > the side and vertical steering distance threshold L5B > the rear steering distance threshold L5C; The hovering distance threshold L6 includes a forward hovering distance threshold L6A, a rear hovering distance threshold L6C, and a side and vertical hovering distance threshold L6B, where the forward hovering distance threshold L6A > the side and vertical hovering distance threshold L6B > the rear hovering distance threshold L6C.

8. The laser ranging anti-collision method according to claim 6, characterized in that: The data acquisition control unit is respectively connected to an alarm device, a steering device, and a driving device through a control module.

9. The laser ranging and anti-collision method according to claim 8, wherein: Within the trigger threshold time t, when the second alarm distance threshold L4 > the measured distance L ≥ the steering distance threshold L5, and several effective intrusion rates are all greater than the effective intrusion rate threshold, the data acquisition control unit controls the alarm device to give an alarm; Within the trigger threshold time t, when the steering distance threshold L5 > the measured distance L ≥ the hovering distance threshold L6, and several effective intrusion rates are all greater than the effective intrusion rate threshold, the data acquisition control unit controls the steering device to steer; Within the trigger threshold time t, when the measured distance L < the hovering distance threshold L6, and several effective intrusion rates are all greater than the effective intrusion rate threshold, the data acquisition control unit controls the driving device to hover.

10. The laser ranging and anti-collision method according to claim 1, wherein: The effective intrusion rate threshold is 30% - 70%.

11. The laser ranging anti-collision method according to claim 10, wherein: The effective intrusion rate threshold is divided into an indoor effective intrusion rate threshold and an outdoor effective intrusion rate threshold; The indoor effective intrusion rate threshold is 30% - 50%, and the outdoor effective intrusion rate threshold is 40% - 70%.

12. The laser ranging anti-collision method according to claim 1, characterized in that: The △t is 100 ms or 120 ms.

13. The laser ranging and collision avoidance method according to claim 1, characterized in that: The trigger threshold time t is 100 - 3000 ms.

14. The laser ranging anti-collision method according to claim 1, wherein: The laser light source module (1), the focusing lens (2), and the receiving plate (3) constitute a laser ranging sensor (10), and the laser ranging sensor (10) is installed on a rotating device (6) to achieve rotational scanning.

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