CN114442120A - Laser ranging anti-collision method - Google Patents
Laser ranging anti-collision method Download PDFInfo
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- CN114442120A CN114442120A CN202011194891.0A CN202011194891A CN114442120A CN 114442120 A CN114442120 A CN 114442120A CN 202011194891 A CN202011194891 A CN 202011194891A CN 114442120 A CN114442120 A CN 114442120A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S17/00—Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
- G01S17/88—Lidar systems specially adapted for specific applications
- G01S17/93—Lidar systems specially adapted for specific applications for anti-collision purposes
- G01S17/931—Lidar systems specially adapted for specific applications for anti-collision purposes of land vehicles
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S17/00—Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
- G01S17/02—Systems using the reflection of electromagnetic waves other than radio waves
- G01S17/06—Systems determining position data of a target
- G01S17/08—Systems determining position data of a target for measuring distance only
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- G—PHYSICS
- G08—SIGNALLING
- G08G—TRAFFIC CONTROL SYSTEMS
- G08G1/00—Traffic control systems for road vehicles
- G08G1/16—Anti-collision systems
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Abstract
The invention discloses a laser ranging anti-collision method with strong anti-interference capability, which comprises the following steps: a, in the movement process of a vehicle or an object, a data acquisition control unit obtains a measured distance L between a travelling crane and an obstacle; b, when the measured distance L is smaller than the set distance threshold, the data acquisition control unit simultaneously measures the number N of emitted laser beams and the number N of received reflection signals within the time delta t; c, calculating to obtain the intrusion rate within delta t time; c1, when the intrusion rate is less than the threshold value, the data acquisition control unit filters the error signal; c2, when the intrusion rate is larger than the threshold value, the data collection control unit sends out alarm signal and/or control signal. The vehicle or object runs in workshop factory building or the open environment of torrential rain that covers a large amount of dust, and laser ranging sensor sends laser signal, and the laser beam can judge and filter the error signal when receiving the interference of dust or rain point, avoids warning in advance, slows down/turns to and brake/hover.
Description
Technical Field
The invention relates to the technical field of laser ranging, in particular to a laser ranging anti-collision method used in the moving process of a vehicle or an object.
Background
Conventional ranging techniques are classified into one-way ranging techniques and two-way ranging techniques. The time-flight principle distance measuring method belongs to the two-way distance measuring technology, and mainly utilizes the round-trip flight time between two asynchronous transceivers to measure the distance between nodes. The time flight principle of the laser is as follows: laser transmitter sends laser pulse wave, and internal timer begins to calculate time t1, and after the object was hit to the laser wave, partial energy returned, when laser receiver received the laser that returns, stopped internal timer t2, and the distance that laser radar arrived the object is: s ═ C × (t2-t1)/2, where C is the speed of light.
Patent document No. 201822207800.7 discloses an overhead traveling crane collision preventing device based on laser range finding sensor, and laser range finding sensor installs on the girder of overhead traveling crane body, and the laser reflecting plate is installed on the side wall of workshop factory building and overhead traveling crane body, and data acquisition control unit, industry all-in-one and audible-visual annunciator all install in the control room of overhead traveling crane body. The overhead traveling crane is in the in-process that traveles in the workshop, laser range finding sensor sends the laser range finding signal, if overhead traveling crane or side wall that other relative traveles were come near in the overhead traveling crane the place ahead, the laser reflecting plate of setting on overhead traveling crane body or side wall can reflect laser signal back laser range finding sensor, after laser range finding sensor received the laser signal that reflects back, with the laser signal transmission to the data acquisition the control unit that reflects back received, the data acquisition the control unit is according to the time difference of laser emission time and receipt time, calculate the distance between two adjacent overhead traveling crane bodies or overhead traveling crane and the side wall. When the distance is less than the safe distance, the data acquisition control unit prompts and gives an alarm on the industrial all-in-one machine, and simultaneously, the audible and visual alarm warns a driver driving the crown block to brake emergently to avoid collision.
Patent document No. 202021261972.3 discloses a biaxial scanning 3D laser radar, and the speculum adopts positive prism platform structure, through the rotation of speculum, reaches the effect of 3D scanning, realizes diversified and multi-angle distance measurement. The patent can realize distance measurement between objects, so the patent can also be applied to distance measurement alarm.
However, the above patent has the following technical problems: when the abominable workshop factory building of production environment, like steel-making workshop etc. a large amount of dust is diffused in the workshop factory building, and laser ranging sensor sends laser signal, and the laser beam receives the interference of dust easily, and the laser beam hits the laser ranging sensor that reflects back on the dust particulate matter promptly, and laser ranging sensor receives this signal and produces the erroneous judgement, reports to the police in advance. In the open air, the condition of alarm misjudgment is easy to occur in rainstorm, haze or foggy weather.
Disclosure of Invention
The invention aims to solve the technical problem of providing a laser ranging anti-collision method with strong anti-interference capability.
The technical scheme adopted by the invention for solving the technical problem is as follows: the laser ranging anti-collision method comprises the following steps:
a, in the process of moving a vehicle or an object, a laser light source module continuously emits pulse laser beams according to frequency, the laser beams are reflected by a focusing lens after passing through an obstacle, and a receiving plate receives reflected signals; the data acquisition control unit obtains the measured distance L between the travelling crane and the barrier;
b, when the measured distance L between the data acquisition control unit and the obstacle is smaller than a set distance threshold, the data acquisition control unit simultaneously measures the number N of emitted laser beams and the number N of received reflected signals within the time delta t;
c, calculating to obtain an effective intrusion rate in the time delta t, namely the number N of received and reflected signals/the number N of emitted laser beams;
c1, when the effective intrusion rate is less than the set effective intrusion rate threshold value, the data acquisition control unit filters error signals;
c2, when the effective intrusion rate is larger than the set effective intrusion rate threshold value, the data acquisition control unit sends out an alarm signal and/or a control signal.
Further, the method also comprises a step D, when the measured distance L between the obstacle and the obstacle is less than a set distance threshold value, the data acquisition control unit simultaneously counts time and forms continuous trigger threshold time t;
the triggering threshold time t is the sum of a plurality of deltat;
and when a plurality of effective intrusion rates within the trigger threshold time t are all larger than the set effective intrusion rate threshold, the data acquisition control unit sends out an alarm signal and/or a control signal.
Further, the set distance threshold in step B includes a first alarm distance threshold L1, a deceleration distance threshold L2, and a braking and stopping distance threshold L3, and the first alarm distance threshold L1 is greater than or equal to the deceleration distance threshold L2 and greater than the braking and stopping distance threshold L3.
Further, the first alarm distance threshold L1 > the deceleration distance threshold L2.
Furthermore, the data acquisition control unit is respectively connected with an alarm device, a brake device and a driving device through a PLC.
Furthermore, within the triggering threshold time t, when the first alarm distance threshold L1 is larger than the detection distance L which is not less than the deceleration distance threshold L2 and a plurality of effective intrusion rates are all larger than the effective intrusion rate threshold, the data acquisition control unit controls the alarm device to alarm;
within the triggering threshold time t, when the deceleration distance threshold L2 is larger than the detection distance L which is not less than the braking and stopping distance threshold L3 and a plurality of effective intrusion rates are all larger than the effective intrusion rate threshold, the data acquisition control unit controls the brake device or the driving device to decelerate;
and in the triggering threshold time t, when the measuring distance L is smaller than the braking and stopping distance threshold value L3 and a plurality of effective intrusion rates are larger than the effective intrusion rate threshold value, the data acquisition control unit controls the braking device to brake and stop.
Further, the set distance threshold in step B includes a second warning distance threshold L4, a turning distance threshold L5, and a hovering distance threshold L6, and the second warning distance threshold L4 is greater than or equal to the turning distance threshold L5 and greater than the hovering distance threshold L6.
Further, the second alarm distance threshold L4 > the steering distance threshold L5.
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, where the front alarm distance threshold L4A > the side and up-down alarm distance threshold L4B > the rear alarm distance threshold L4C;
the steering distance threshold L5 includes a forward steering distance threshold L5A, a rearward steering distance threshold L5C, and a lateral and up-down steering distance threshold L5B, the forward steering distance threshold L5A > a lateral and up-down steering distance threshold L5B > a rearward steering distance threshold L5C;
the hover distance threshold L6 includes a front hover distance threshold L6A, a rear hover distance threshold L6C, and side and up-down hover distance thresholds L6B, the front hover distance threshold L6A > side and up-down hover distance threshold L6B > rear hover distance threshold L6C.
Furthermore, the data acquisition control unit is respectively connected with the alarm device, the steering device and the driving device through the control module.
Furthermore, within the triggering threshold time t, when the second alarm distance threshold L4 is larger than the detection distance L which is not less than the steering distance threshold L5 and a plurality of effective intrusion rates are all larger than the effective intrusion rate threshold, the data acquisition control unit controls the alarm device to alarm;
within the triggering threshold time t, when the steering distance threshold L5 is larger than the detection distance L which is not less than the hovering distance threshold L6 and a plurality of effective intrusion rates are all larger than the effective intrusion rate threshold, the data acquisition control unit controls the steering device to steer;
and in the triggering threshold time t, when the measured distance L is smaller than the hovering distance threshold L6 and a plurality of effective intrusion rates are all larger than the effective intrusion rate threshold, the data acquisition control unit controls the driving device to hover.
Further, the effective intrusion rate threshold value is 30% -70%.
Further, the effective intrusion rate threshold value is divided into an indoor effective intrusion rate threshold value and an outdoor effective intrusion rate threshold value;
the threshold value of the indoor effective intrusion rate is 30% -50%, and the threshold value of the outdoor effective intrusion rate is 40% -70%.
Further, Δ t is 100ms or 120 ms.
Further, the trigger threshold time t is 100-3000 ms.
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 the rotating device to realize rotary scanning.
Compared with the prior art, the invention has the beneficial effects that: the invention provides a laser ranging anti-collision method with strong anti-interference capability. The vehicle or object runs in workshop factory building or the open environment of torrential rain that covers a large amount of dust, and laser ranging sensor sends laser signal, and the laser beam can judge and filter the error signal when receiving the interference of dust or rain point, avoids warning in advance, slows down/turns to and brake/hover. The device can accurately send out alarm signals and control signals, and has strong anti-interference capability.
Drawings
FIG. 1 is a schematic diagram of the laser ranging sensor of the present invention;
FIG. 2 is a control flow chart of the present invention applied to a traveling vehicle;
fig. 3 is a control flow diagram of the present invention applied to a drone;
reference numerals: 1-a laser light source module; 2-a focusing lens; 3-receiving a plate; 4-a crane body; 5-an obstacle; 6-a rotating device; 10-laser ranging sensor.
Detailed Description
The invention is further illustrated with reference to the following figures and examples.
As shown in fig. 1, due to the particularity of the traveling crane, the traveling crane runs in a straight line, so that a laser ranging sensor 10 is mounted on a traveling crane body 4, and a laser light source module 1, a focusing lens 2, a receiving plate 3 and the like are integrally arranged in the laser ranging sensor 10. The laser light source module 1 includes a laser light source and a collimating lens, a laser beam emitted from the laser light source is emitted after passing through the collimating lens to form an emission beam, and a reflected beam reflected back through the barrier 5 is focused by the focusing lens 2 and then converged on the receiving plate 3. Based on the time flight distance measurement principle, the distance value between the travelling crane and the obstacle 5 which are detected in real time is calculated through the difference between the sending time of the laser light source and the receiving time of the receiving plate 3, the data acquisition control unit can make judgment according to the detected distance value, and when the detected distance value meets the set condition, the data acquisition control unit sends an alarm signal or a control signal. When the brake is applied to driving, the control signals comprise a deceleration signal and a brake stop signal. The deceleration signal is used to control deceleration of the drive device or braking deceleration of the brake device. The brake stop signal is used for controlling the brake stop of the brake device.
As shown in the attached figure 1, for the need to carry out distance measurement and monitoring to the horizontal direction of operation, such as the operation of automobile and train, and the left and right directions in the driving operation, in order to enlarge the scanning area in the horizontal plane and even 360 degrees all-round scanning, install rotating device 6 below laser range sensor 10, rotating device 6 drives the rotation at certain angle reciprocating rotation or 360 degrees rotation through driving motor, thereby realize horizontal two-dimensional scanning, detect the distance of different directions, can also set up different distance threshold values, effective intrusion rate threshold value in different directions as required simultaneously, and send out warning and control signal through judging. In a similar way, 3D scanning laser radar can be adopted to carry out distance detection in all directions and at multiple angles, and alarm and control are realized, so that the unmanned aerial vehicle is more suitable for being used in the complex situation of peripheral obstacles or in the large unmanned aerial vehicle with a large operation range. At this time, the control signal includes a turn signal and a hover signal. The steering signal is used for controlling the steering device to adjust the flight direction of the unmanned aerial vehicle. The hovering signal is used for controlling the driving device to realize that the unmanned aerial vehicle hovers in the air.
The invention relates to a laser ranging anti-collision method, which comprises the following steps:
a, in the process of moving a vehicle or an object, a laser light source module 1 continuously emits pulse laser beams according to frequency, the laser beams are reflected by a focusing lens 2 after passing through an obstacle 5, and a receiving plate 3 receives reflected signals; the data acquisition control unit obtains the measured distance L between the travelling crane and the barrier 5;
b, when the measured distance L between the obstacle 5 and the obstacle is smaller than a set distance threshold, the data acquisition control unit simultaneously measures the number N of emitted laser beams and the number N of received reflected signals within the time delta t;
c, calculating to obtain an effective intrusion rate in the time delta t, namely the number N of received and reflected signals/the number N of emitted laser beams;
c1, when the effective intrusion rate is less than the set effective intrusion rate threshold value, the data acquisition control unit filters error signals;
c2, when the effective intrusion rate is larger than the set effective intrusion rate threshold value, the data acquisition control unit sends out an alarm signal or a control signal.
When the device is applied to driving, the data acquisition control unit is respectively connected with the alarm device, the brake device and the driving device through the PLC. The effective intrusion rate threshold value can be set according to actual needs. The effective intrusion rate threshold value is 30% -70%. In the above steps, the set distance thresholds include a first warning distance threshold L1, a deceleration distance threshold L2, and a braking and stopping distance threshold L3, and the first warning distance threshold L1 is greater than or equal to the deceleration distance threshold L2 > the braking and stopping distance threshold L3. When the first alarm distance threshold value L1 is equal to the deceleration distance threshold value L2, the data acquisition control unit controls the alarm device to alarm through the PLC, and controls the traveling crane to decelerate through the PLC. Preferably, the first alarm distance threshold value L1 > the deceleration distance threshold value L2 > the brake stopping distance threshold value L3. When the measured distance L is smaller than the first alarm distance threshold value L1, the driving safety distance needs to be prompted, and when the distance is relatively long, an alarm prompt is sent out first to remind people to pay attention. When the traveling crane enters the deceleration distance, namely the measured distance L is less than the deceleration distance threshold value L2, the data acquisition control unit controls the deceleration of the traveling crane through the PLC. During speed reduction control, the PLC can control a driving motor of a travelling crane to enable the driving motor to run at a reduced speed; the braking device can also be controlled to decelerate the vehicle. When the traveling crane enters the braking and stopping distance, namely the measuring distance L is less than the braking and stopping distance threshold value L3, the data acquisition control unit carries out emergency braking and stopping on the traveling crane through the PLC. When braking and parking, the PLC only controls the braking device to realize emergency parking of the traveling crane.
In the experiment, the effective invasion rate in one or more times delta t is larger than the set effective invasion rate, but the obstacle 5 measured in front is still unrealistic. In this case, at least one effective intrusion rate in the time Δ t is smaller than the set effective intrusion rate, that is, the effective intrusion rates in not all the time Δ t are larger than the set effective intrusion rate. The reason is that the dust particles or the raindrops are spatially arranged in the one or more Δ t time, so that the reflected light beams reflected by the dust particles or the raindrops are more, the effective intrusion rate in one or more Δ t time is larger than the set effective intrusion rate, and the effective intrusion rate in not all the Δ t time is larger than the set effective intrusion rate. In order to prevent the above situation from occurring, erroneous judgment is generated. Therefore, the data acquisition control unit starts timing from the first measured pulse signal smaller than the distance threshold and forms a continuous trigger threshold time t, wherein the trigger threshold time t is the sum of a plurality of deltat. And in the triggering threshold time t, the data acquisition control unit filters the condition that the effective intrusion rate in one or more delta t time is larger than the set effective intrusion rate threshold value, namely the effective intrusion rate in at least one delta t time is smaller than the set effective intrusion rate. The obstacle 5 can be said to be real only if a number of effective intrusion rates within the trigger threshold time t are all greater than the effective intrusion rate threshold. And the data acquisition control unit sends out an alarm signal and/or a control signal by combining the size relationship between the measured distance L and the set distance threshold, so that the judgment accuracy is ensured. The trigger threshold time t can be set according to the requirement, and is 100-3000 ms.
In order to further expand the application 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 threshold value of the indoor effective intrusion rate is 30% -50%, and the threshold value of the outdoor effective intrusion rate is 40% -70%. The indoor reflection threshold value is correspondingly suitable for the indoor environment, and the outdoor reflection threshold value is correspondingly suitable for the outdoor environment.
The first embodiment is as follows:
the crane body 4 is installed in a factory environment where a large amount of dust particles are diffused. The laser distance measuring sensor 10 is installed on the vehicle body 4 and is installed at the front end of the traveling running direction V as far as possible. The laser ranging sensor 10 is provided with a laser light source module 1, a focusing lens 2 and a receiving plate 3. The signals received by the receiving plate 3 are processed by a data acquisition control unit, and the data acquisition control unit is respectively connected with an alarm device, a brake device and a driving device. The alarm device comprises one or a combination of sound alarm and light alarm. And after the control signal of the data acquisition control unit passes through the PLC, the driving device and the braking device of the traveling crane are controlled, so that the deceleration and the braking parking are realized.
Step 1: in the running process, the laser light source module 1 continuously emits pulse laser beams according to the frequency of 1000Hz, the laser beams are reflected by the focusing lens 2 after passing through the barrier 5, and the receiving plate 3 receives reflected signals; the data acquisition control unit obtains the measured distance L between the vehicle and the obstacle 5.
Step 2: the data acquisition control unit compares the measured distance L with a set distance threshold. Distance thresholds are set, including a first warning distance threshold L1, a deceleration distance threshold L2, and a brake park distance threshold L3. The first warning distance threshold L1 is 10m, the deceleration distance threshold L2 is 6m, and the brake stopping distance threshold L3 is 3 m.
When the measured distance L is less than the first alarm distance threshold value L1, the data acquisition control unit starts measuring the quantity N of emitted laser beams and the quantity N of received reflected signals within 100ms of delta t time from the first measured pulse signal which is less than the first alarm distance threshold value L1.
And step 3: when the measured distance L between the obstacle 5 and the obstacle is less than a first alarm distance threshold value L1, the data acquisition control unit counts time at the same time and forms a continuous trigger threshold time t; the triggering threshold time t is the sum of a plurality of deltat; and comparing a plurality of effective intrusion rates within the trigger threshold time t with the set indoor effective intrusion rate threshold respectively. The trigger threshold time t is 500ms, comprising 5 Δ t times.
And 4, step 4: the data acquisition control unit calculates the effective intrusion rate in delta t time, namely the number N of received reflection signals/the number N of emitted laser beams, and compares the calculated effective intrusion rate with a set indoor effective intrusion rate threshold value of 50%.
The dust is distributed in a three-dimensional point shape in the air, and a gap is formed between any two adjacent dust particles. A small number of emitted light beams impinge on the dust particles, and a large number of emitted light beams pass through the gap and emit to far away. A small amount of emission beams striking on the dust particles are subjected to diffuse reflection on the outer surface of the dust particles to form dust reflection beams. Most of the dust reflected beam is scattered in the air, and a very small part of the dust reflected beam is received by the laser ranging sensor 10. The emitted light beam is diffusely reflected on the surface of an obstacle 5 such as a front vehicle or a side wall, most of the reflected light beam of the obstacle is scattered in the air, and a small part of the reflected light beam of the obstacle is received by the laser ranging sensor 10.
(1) Within the triggering threshold time t, when the first alarm distance threshold L1 is larger than the detection distance L which is larger than or equal to the deceleration distance threshold L2, namely: when the measuring distance L is more than 10m and is more than or equal to 6m, and the effective intrusion rates of a plurality of obstacles are all more than the set indoor effective intrusion rate threshold value 50%, the obstacle 5 measured in front is real, and the data acquisition control unit sends out an alarm signal to prompt personnel to process; when any one or more effective intrusion rates are smaller than the set indoor effective intrusion rate threshold value by 50%, the obstacle signal measured in front is an error signal, and the data acquisition control unit does not send out an alarm signal.
(2) Within the triggering threshold time t, when the deceleration distance threshold L2 is larger than the detection distance L which is larger than or equal to the braking and stopping distance threshold L3, namely: when the measuring distance L is more than 6m and is more than or equal to 3m, and the effective invasion rates of a plurality of obstacles are all more than the set indoor effective invasion rate threshold value 50%, the obstacle 5 measured in front is real, and the data acquisition control unit controls the travelling crane to decelerate through the PLC; when any one or more effective intrusion rates are smaller than the set indoor effective intrusion rate threshold value by 50%, the obstacle signal measured in front is an error signal, and the data acquisition control unit does not send a deceleration signal.
(3) When the measured distance L < the braking and stopping distance threshold value L3 within the triggering threshold time t, namely: when the measured distance L is less than 3m and a plurality of effective intrusion rates are all greater than a set indoor effective intrusion rate threshold value by 50%, the obstacle 5 measured in front is real, and the data acquisition control unit controls the brake device to brake and stop; when any one or more effective intrusion rates are smaller than the set indoor effective intrusion rate threshold value by 50%, the obstacle signal measured in front is a false signal, and the data acquisition control unit does not send out a braking and stopping signal.
Example two:
the vehicle body 4 is installed in an open rainstorm environment. The laser distance measuring sensor 10 is installed on the traveling crane body 4 and is installed at the front end of the traveling crane running direction V as far as possible. The laser ranging sensor 10 is provided with a laser light source module 1, a focusing lens 2 and a receiving plate 3. The signals received by the receiving plate 3 are processed by a data acquisition control unit, and the data acquisition control unit is respectively connected with an alarm device, a brake device and a driving device. The alarm device comprises one or a combination of sound alarm and light alarm. After the control signal of the control processor passes through the PLC, the driving device and the braking device of the traveling crane are controlled, and deceleration and braking parking are realized.
Step 1: in the running process, the laser light source module 1 continuously emits pulse laser beams according to the frequency of 1000Hz, the laser beams are reflected by the focusing lens 2 after passing through the barrier 5, and the receiving plate 3 receives reflected signals; the data acquisition control unit obtains the measured distance L between the vehicle and the obstacle 5.
Step 2: the data acquisition control unit compares the measured distance L with a set distance threshold. Distance thresholds are set, including a first warning distance threshold L1, a deceleration distance threshold L2, and a brake park distance threshold L3. The first warning distance threshold L1 is 10m, the deceleration distance threshold L2 is 6m, and the brake stopping distance threshold L3 is 3 m.
When the measured distance L is less than the first alarm distance threshold value L1, the data acquisition control unit starts measuring the quantity N of emitted laser beams and the quantity N of received reflected signals within 100ms of delta t time from the first measured pulse signal which is less than the first alarm distance threshold value L1.
And step 3: when the measured distance L between the obstacle 5 and the obstacle is less than a first alarm distance threshold value L1, the data acquisition control unit counts time at the same time and forms a continuous trigger threshold time t; the triggering threshold time t is the sum of a plurality of deltat; and comparing a plurality of effective intrusion rates within the trigger threshold time t with the set outdoor effective intrusion rate threshold respectively. The trigger threshold time t is 500ms, comprising 5 Δ t times.
And 4, step 4: the data acquisition control unit calculates the effective intrusion rate within the time delta t, namely the number N of the received reflection signals/the number N of the emitted laser beams, and compares the calculated effective intrusion rate with a set outdoor effective intrusion rate threshold value of 60%.
The raindrops are densely distributed in the air, and a gap is formed between any two adjacent raindrops. A small number of the emission beams impinge on the raindrops and a large number of the emission beams pass through the gaps to emit to a remote place. A small amount of emission light beams striking the raindrop are subjected to diffuse reflection on the outer surface of the raindrop to form raindrop reflection 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 beam is diffusely reflected on the surface of an obstacle 5 such as a front vehicle or a side wall, most of the reflected light beam of the obstacle is scattered in the air, and a small part of the reflected light beam of the obstacle is received by the laser ranging sensor 10.
(1) Within the triggering threshold time t, when the first alarm distance threshold L1 is larger than the detection distance L which is larger than or equal to the deceleration distance threshold L2, namely: when the measuring distance L is more than 10m and is more than or equal to 6m, and the effective intrusion rates of a plurality of obstacles are all more than the set outdoor effective intrusion rate threshold value 60%, the obstacle 5 measured in front is real, and the data acquisition control unit sends out an alarm signal to prompt personnel to process; when any one or more effective intrusion rates are smaller than the set outdoor effective intrusion rate threshold value by 60%, the obstacle signal measured in front is an error signal, and the data acquisition control unit does not send out an alarm signal.
(2) Within the triggering threshold time t, when the deceleration distance threshold L2 is larger than the detection distance L which is larger than or equal to the braking and stopping distance threshold L3, namely: when the measuring distance L is more than 6m and is more than or equal to 3m, and the effective invasion rates of a plurality of obstacles are all more than the set outdoor effective invasion rate threshold value 60%, the obstacle 5 measured in front is real, and the data acquisition control unit controls the driving to decelerate through the PLC; when any one or more effective intrusion rates are smaller than the set outdoor effective intrusion rate threshold value by 60%, the obstacle signal measured in front is an error signal, and the data acquisition control unit does not send a deceleration signal.
(3) When the measured distance L < the braking and stopping distance threshold value L3 within the triggering threshold time t, namely: when the measured distance L is less than 3m and a plurality of effective intrusion rates are all larger than a set outdoor effective intrusion rate threshold value by 60%, the obstacle 5 measured in front is real, and the data acquisition control unit controls the brake device to brake and stop; when any one or more effective intrusion rates are smaller than the set outdoor effective intrusion rate threshold value by 60%, the obstacle signal measured in front is a false signal, and the data acquisition control unit does not send out a braking and stopping signal.
When being applied to unmanned aerial vehicle, the data acquisition control unit passes through control module and connects alarm device, turns to device and drive arrangement respectively. The effective intrusion rate threshold value can be set according to actual needs. The effective intrusion rate threshold value is 30% -70%. In the above steps, the set distance thresholds include a second warning distance threshold L4, a turning distance threshold L5 and a hovering distance threshold L6, and the second warning distance threshold L4 is greater than or equal to the turning distance threshold L5 > the hovering distance threshold L6. When the second alarm distance threshold L4 is the steering distance threshold L5, the data acquisition control unit controls the alarm device to alarm through the control module, and controls the unmanned aerial vehicle to steer through the control module. Preferably, the second warning distance threshold L4 > the turning distance threshold L5 > the hovering distance threshold L6. When the measured distance L is smaller than the second alarm distance threshold value L4, the unmanned aerial vehicle needs to be prompted within the safety distance, and when the distance is relatively far, an alarm prompt is sent out first to remind people of paying attention. When the unmanned aerial vehicle enters the steering distance, namely the measuring distance L is smaller than the steering distance threshold value L5, the data acquisition control unit controls the steering of the unmanned aerial vehicle through the control module. When steering, the control module controls the steering device. When the unmanned aerial vehicle enters the hovering distance, namely the measured distance L is smaller than the hovering distance threshold value L6, the data acquisition control unit performs emergency hovering on the unmanned aerial vehicle through the control module. And when the suspension is stopped, the control module controls the driving device.
Example three:
install the laser rangefinder sensor that 3D detected on unmanned aerial vehicle fuselage. The laser ranging sensor 10 is provided with a laser light source module 1, a focusing lens 2, a receiving plate 3 and a reflector with a regular prism structure. The signal received by the receiving plate 3 is processed by a 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 comprises one or a combination of sound alarm and light alarm arranged on the unmanned aerial vehicle operation controller.
Step 1: in the flight of unmanned aerial vehicle, 3D laser radar's laser light source module 1 sends the pulse laser beam according to frequency 900Hz in succession, and the laser beam launches after the speculum reflection of positive prism platform structure, and the speculum rotates, realizes the scanning of opposite. The emitted light beam is reflected by the barrier 5 to form a reflected light beam, and the reflected light beam is reflected by the reflecting mirror, focused by the focusing lens 2 and then received by the receiving plate 3; the data acquisition control unit obtains the measured distance L between the vehicle and the obstacle 5.
Step 2: the data acquisition control unit compares the measured distance L with a set distance threshold. Because unmanned aerial vehicle functioning speed requires shorter to the time of the collision in the front, sets up the value difference of second warning distance threshold value L4 in different directions, includes: the front alarm distance threshold L4A is 12m, the side and upper alarm distance threshold L4B is 5m, and the rear alarm distance threshold L4C is 3 m. Setting a steering distance threshold L5, including: the front steering distance threshold L5A is 4m, the side and up-down steering distance threshold L5B is 2m, and the rear steering distance threshold L5C is 1 m. Setting a hover distance threshold L6, comprising: the forward hovering distance threshold L6A is 3m, the side and up-down hovering distance threshold L6B is 1m, and the rear hovering distance threshold L6C is 0.5 m.
When the measured distance L is less than a second alarm distance threshold value L4 of the corresponding direction, the data acquisition control unit starts to measure the quantity N of emitted laser beams and the quantity N of received reflected signals when the measured distance L is less than the corresponding set distance threshold value within the time delta t of 120ms from the first measured pulse signal which is less than the second alarm distance threshold value L4.
And step 3: when the measured distance L between the data acquisition control unit and the obstacle 5 is smaller than a second alarm distance threshold value L4 in the corresponding direction, the data acquisition control unit counts time at the same time and forms a continuous trigger threshold value time t; the triggering threshold time t is the sum of a plurality of deltat; and comparing a plurality of effective intrusion rates within the trigger threshold time t with the set outdoor effective intrusion rate threshold respectively. The trigger threshold time t is 600ms, including 5 Δ t times.
And 4, step 4: the data acquisition control unit calculates the effective intrusion rate within the time delta t, namely the number N of the received reflected signals/the number N of the emitted laser beams, and compares the calculated effective intrusion rate with a set outdoor effective intrusion rate threshold value of 70%. In this case, different effective intrusion rate thresholds may be set according to different directions.
(1) Within the time t of the trigger threshold, when a second alarm distance threshold L4 is larger than a measured distance L which is not less than a steering distance threshold L5, if the distance is measured when the flight is 12m larger than the measured distance, and a plurality of effective intrusion rates are all larger than a set outdoor effective intrusion rate threshold value of 70%, the obstacle 5 measured in front is real, and the data acquisition control unit sends out an alarm signal to prompt a person to process; when any one or more effective intrusion rates are smaller than the set outdoor effective intrusion rate threshold value by 70%, the obstacle signal measured in front is an error signal, and the data acquisition control unit does not send out an alarm signal.
(2) When a steering distance threshold value L5 is larger than a measured distance L within a trigger threshold value time t, if a flight direction side face 2m is larger than the measured distance L, and a plurality of effective intrusion rates are all larger than a set outdoor effective intrusion rate threshold value 70%, the obstacle 5 measured in front is real, and the data acquisition control unit controls the unmanned aerial vehicle to change the direction; when any one or more effective intrusion rates are smaller than the set outdoor effective intrusion rate threshold value by 70%, the obstacle signal measured in front is an error signal, and the data acquisition control unit does not send a steering signal.
(3) When the hovering distance threshold value L6 is larger than the measuring distance L within the triggering threshold value time t, if the flying direction side face 1m is larger than the measuring distance L, and the effective intrusion rates are all larger than the set outdoor effective intrusion rate threshold value 70%, the obstacle 5 measured in front is real, and the data acquisition control unit controls the unmanned aerial vehicle to hover; when any one or more effective intrusion rates are smaller than the set outdoor effective intrusion rate threshold value by 70%, the obstacle signal measured in front is an error signal, and the data acquisition control unit does not send out a hovering signal.
The above is a specific implementation manner of the present invention, and it can be seen from the implementation process that the present invention provides a laser ranging collision avoidance method with strong anti-interference capability. The vehicle or object runs in workshop factory building or the open environment of torrential rain that covers a large amount of dust, and laser ranging sensor sends laser signal, and the laser beam can judge and filter the error signal when receiving the interference of dust or rain point, avoids warning in advance, slows down/turns to and brake/hover. The device can accurately send out alarm signals and control signals, and has strong anti-interference capability.
Claims (16)
1. The laser ranging anti-collision method is characterized in that: the method comprises the following steps:
a, in the process of moving a vehicle or an object, a laser light source module (1) continuously emits pulse laser beams according to frequency, the laser beams are reflected by a focusing lens (2) after passing through an obstacle (5), and a receiving plate (3) receives reflected signals; the data acquisition control unit obtains the measured distance L between the travelling crane and the barrier (5);
b, when the measured distance L between the obstacle (5) and the obstacle is smaller than a set distance threshold, the data acquisition control unit simultaneously measures the number N of emitted laser beams and the number N of received reflected signals within the time delta t;
c, calculating to obtain an effective intrusion rate in the time delta t, namely the number N of received and reflected signals/the number N of emitted laser beams;
c1, when the effective intrusion rate is less than the set effective intrusion rate threshold value, the data acquisition control unit filters error signals;
c2, when the effective intrusion rate is larger than the set effective intrusion rate threshold value, the data acquisition control unit sends out an alarm signal and/or a control signal.
2. The laser ranging collision avoidance method of claim 1, wherein: the method also comprises a step D, when the measured distance L between the obstacle (5) and the obstacle is less than a set distance threshold, the data acquisition control unit simultaneously counts time and forms continuous trigger threshold time t;
the triggering threshold time t is the sum of a plurality of deltat;
and when a plurality of effective intrusion rates within the trigger threshold time t are all larger than the set effective intrusion rate threshold, the data acquisition control unit sends out an alarm signal and/or a control signal.
3. The laser ranging collision avoidance method of claim 2, wherein: the set distance threshold in the step B comprises a first alarm distance threshold L1, a deceleration distance threshold L2 and a braking and stopping distance threshold L3, and the first alarm distance threshold L1 is more than or equal to the deceleration distance threshold L2 and more than the braking and stopping distance threshold L3.
4. The laser ranging collision avoidance method of claim 3, wherein: the first warning distance threshold L1 > a deceleration distance threshold L2.
5. The laser ranging collision avoidance method of claim 4, wherein: the data acquisition control unit is respectively connected with the alarm device, the brake device and the driving device through a PLC.
6. The laser ranging collision avoidance method of claim 5, wherein: within the triggering threshold time t, when the first alarm distance threshold L1 is larger than the detection distance L which is not less than the deceleration distance threshold L2 and a plurality of effective intrusion rates are all larger than the effective intrusion rate threshold, the data acquisition control unit controls the alarm device to alarm;
within the triggering threshold time t, when the deceleration distance threshold L2 is larger than the detection distance L which is not less than the braking and stopping distance threshold L3 and a plurality of effective intrusion rates are all larger than the effective intrusion rate threshold, the data acquisition control unit controls the brake device or the driving device to decelerate;
and in the triggering threshold time t, when the measuring distance L is smaller than the braking and stopping distance threshold value L3 and a plurality of effective intrusion rates are larger than the effective intrusion rate threshold value, the data acquisition control unit controls the braking device to brake and stop.
7. The laser ranging collision avoidance method of claim 2, wherein: the set distance threshold in the step B comprises a second alarm distance threshold L4, a steering distance threshold L5 and a hovering distance threshold L6, and the second alarm distance threshold L4 is more than or equal to the steering distance threshold L5 and is more than the hovering distance threshold L6.
8. The laser ranging collision avoidance method of claim 7, wherein: the second warning distance threshold L4 > a steering distance threshold L5.
9. The laser ranging collision avoidance method of claim 7, wherein: the second alarm distance threshold value L4 comprises a front alarm distance threshold value L4A, a rear alarm distance threshold value L4C, a side surface and upper and lower alarm distance threshold values L4B, wherein the front alarm distance threshold value L4A is greater than the side surface and upper and lower alarm distance threshold values L4B is greater than the rear alarm distance threshold value L4C;
the steering distance threshold L5 includes a forward steering distance threshold L5A, a rearward steering distance threshold L5C, and a lateral and up-down steering distance threshold L5B, the forward steering distance threshold L5A > a lateral and up-down steering distance threshold L5B > a rearward steering distance threshold L5C;
the hover distance threshold L6 includes a front hover distance threshold L6A, a rear hover distance threshold L6C, and side and up-down hover distance thresholds L6B, the front hover distance threshold L6A > side and up-down hover distance threshold L6B > rear hover distance threshold L6C.
10. The laser ranging collision avoidance method of claim 8, wherein: the data acquisition control unit is respectively connected with the alarm device, the steering device and the driving device through the control module.
11. The laser ranging collision avoidance method of claim 10, wherein: within the triggering threshold time t, when the second alarm distance threshold L4 is larger than the detection distance L which is not less than the steering distance threshold L5 and a plurality of effective intrusion rates are all larger than the effective intrusion rate threshold, the data acquisition control unit controls the alarm device to alarm;
within the triggering threshold time t, when the steering distance threshold L5 is larger than the detection distance L which is not less than the hovering distance threshold L6 and a plurality of effective intrusion rates are all larger than the effective intrusion rate threshold, the data acquisition control unit controls the steering device to steer;
and in the triggering threshold time t, when the measured distance L is smaller than the hovering distance threshold L6 and a plurality of effective intrusion rates are all larger than the effective intrusion rate threshold, the data acquisition control unit controls the driving device to hover.
12. The laser ranging collision avoidance method of claim 1, wherein: the effective intrusion rate threshold value is 30% -70%.
13. The laser ranging collision avoidance method of claim 12, wherein: the effective intrusion rate threshold value is divided into an indoor effective intrusion rate threshold value and an outdoor effective intrusion rate threshold value;
the threshold value of the indoor effective intrusion rate is 30% -50%, and the threshold value of the outdoor effective intrusion rate is 40% -70%.
14. The laser ranging collision avoidance method of claim 1, wherein: the delta t is 100ms or 120 ms.
15. The laser ranging collision avoidance method of claim 1, wherein: the trigger threshold time t is 100-3000 ms.
16. The laser ranging collision avoidance method of claim 1, wherein: the laser ranging device is characterized in that the laser light source module (1), the focusing lens (2) and the receiving plate (3) form a laser ranging sensor (10), and the laser ranging sensor (10) is installed on the rotating device (6) to achieve rotary scanning.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115352495A (en) * | 2022-07-27 | 2022-11-18 | 苏州北醒科技有限公司 | Early warning device and early warning method based on laser ranging |
| CN115576360A (en) * | 2022-10-12 | 2023-01-06 | 华能南京金陵发电有限公司 | Anti-collision control method for bucket wheel machine |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115352495A (en) * | 2022-07-27 | 2022-11-18 | 苏州北醒科技有限公司 | Early warning device and early warning method based on laser ranging |
| CN115576360A (en) * | 2022-10-12 | 2023-01-06 | 华能南京金陵发电有限公司 | Anti-collision control method for bucket wheel machine |
| CN115576360B (en) * | 2022-10-12 | 2023-11-07 | 华能南京金陵发电有限公司 | Anti-collision control method for bucket wheel machine |
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