Disclosure of Invention
In order to overcome the defects of the prior art, the invention provides a multi-sensor fusion-based method and a multi-sensor fusion-based system for preventing smashing of cabin operators, which are used for detecting personnel and a grab bucket by means of a single sensor such as a camera or a laser radar at present, but the problems of inaccurate identification or high false alarm rate often occur under the conditions of low illumination, dust interference and goods shielding of the cabin, and the existing system is mainly based on acousto-optic alarm prompt, cannot form linkage with personnel wearing equipment or mechanical control of the grab bucket, and is difficult to block dangerous actions in time.
In order to achieve the above purpose, the present invention provides the following technical solutions:
A cabin worker smashing prevention method based on multi-sensor fusion comprises the following steps:
Acquiring a grab bucket movement track and a personnel movement track through laser radar real-time scanning, and dynamically defining a safe area and a non-safe area according to the grab bucket movement track;
Carrying out smashing prevention risk identification on the personnel movement track in the unsafe area, and judging smashing prevention risk according to the grab bucket movement track and the personnel movement track in the unsafe area;
For an unsafe area with anti-smashing risk, acquiring grab bucket movement signals and personnel movement signals based on a UWB positioning unit, combining grab bucket movement tracks in the unsafe area with the grab bucket movement signals to check the first track matching degree, combining personnel movement tracks with the personnel movement signals to check the second track matching degree, and checking the authenticity of the anti-smashing risk according to the first track matching degree and the second track matching degree;
And triggering a crane PLC execution module to link grab bucket control operation and warning personnel according to the risk classification result for determining the risk classification risk level of the smashing prevention.
As a further scheme of the invention, the motion trail of the grab bucket and the motion trail of the personnel are obtained through laser radar real-time scanning, and a safe area and a non-safe area are dynamically defined according to the motion trail of the grab bucket, and the method comprises the following specific steps:
The method comprises the steps of scanning and collecting three-dimensional point clouds of a cabin operation area in real time through a laser radar, respectively identifying grab bucket targets and personnel targets through a point cloud clustering and tracking algorithm, respectively performing motion trail fitting based on the grab bucket targets and the personnel targets to obtain grab bucket motion trails and personnel motion trails, extracting first space motion characteristics based on the grab bucket motion trails, and extracting second space motion characteristics based on the personnel motion trails, wherein the space motion characteristics comprise speed characteristics and acceleration characteristics;
and extracting the grab bucket movement track and the first space movement characteristic to dynamically define an unsafe area, and marking the area except the unsafe area of the cabin operation area as the safe area.
The method comprises the specific steps of obtaining a grab bucket movement track point gamma 1(t)=(x1(t),y1(t),z1 (t)) at the moment t, wherein (x 1(t),y1(t),z1 (t)) is the position coordinate of the grab bucket centroid at the moment t, and defining a neighborhood omega 1 (t) of the grab bucket movement track gamma 1 (t);
Predicting a grab bucket movement track Γ 1 (t+DeltaT) in a sampling period DeltaT time period;
Predicting unsafe areas based on grab bucket movement tracks in a sampling period delta T time period to obtain omega 1 (t+delta T), calculating each sampling period delta T to obtain corresponding unsafe areas, and performing intersection operation based on the corresponding unsafe areas and personnel movement tracks gamma 2(t)=(x2(t),y2(t),z2 (T)) to obtain R ns(t)=Ω1(t+ΔT)∩Γ2 (T);
R ns (T) is an intersection output result, omega 1 (t+DeltaT) is a corresponding unsafe region in a sampling period DeltaT time period, and Γ 2 (T) is a personnel movement track at the moment T;
and dynamically judging whether the personnel are in the unsafe area according to the intersection output result, if the intersection output result is not an empty set, judging that the personnel are in the unsafe area, and if the intersection output result is an empty set, judging that the personnel are in the safe area.
Analyzing the track coincidence degree according to the grab bucket movement track and the personnel movement track in the unsafe area, judging the anti-smashing risk, and specifically comprising the following steps:
If the person is in the unsafe area, acquiring the grab bucket movement track and the person movement track at the moment, and calculating the intersection proportion of the two movement tracks in a time window as the track coincidence ratio;
And comparing the track overlap ratio with a preset threshold, if the track overlap ratio is greater than or equal to the preset threshold, primarily judging that the risk exists, and if the track overlap ratio is less than the preset threshold, primarily judging that the risk does not exist.
As a further scheme of the invention, for the unsafe area with risk of smashing prevention, a grab bucket movement signal and a personnel movement signal are acquired based on a UWB positioning unit, the grab bucket movement track in the unsafe area is combined with the grab bucket movement signal to check the first track matching degree, the personnel movement track is combined with the personnel movement signal to check the second track matching degree, and the authenticity of the risk of smashing prevention is checked according to the first track matching degree and the second track matching degree, and the specific steps are as follows:
positioning base stations in the UWB positioning units are deployed at four corners of a cabin operation area, a first UWB signal is obtained through a first positioning tag on a personnel helmet, and a second UWB signal is obtained based on a second positioning tag on a grab bucket;
Respectively carrying out two-way distance measurement on the first positioning tag and the second positioning tag with four base stations, and calculating to obtain the distance from the first positioning tag to each base station as a first distance, and the distance from the second positioning tag to each base station as a second distance;
Transmitting the first distance and the second distance to a central positioning engine through a wired network;
the central positioning engine respectively calculates real-time three-dimensional coordinates of the grab bucket and real-time three-dimensional coordinates of a helmet wearer according to the first distance and the second distance by using a trilateration method, and takes the real-time three-dimensional coordinates of the grab bucket as grab bucket movement signals and the real-time three-dimensional coordinates of the helmet wearer as personnel movement signals;
The method comprises the steps of obtaining a grab bucket movement track and a personnel movement track, calculating Euclidean distance between the grab bucket movement track and a grab bucket movement signal at the same time in real time as a first distance value, calculating Euclidean distance between the personnel movement track and the personnel movement signal at the same time as a second distance value, comparing the first distance value and the second distance value with a preset distance threshold value respectively, if the first distance value is larger than or equal to the preset distance threshold value, the authenticity of the anti-smashing risk is unreliable, if the first distance value is smaller than the preset distance threshold value, the authenticity of the anti-smashing risk is reliable, if the second distance value is larger than or equal to the preset distance threshold value, the authenticity of the anti-smashing risk is unreliable, and if the second distance value is smaller than the preset distance threshold value, the authenticity of the anti-smashing risk is reliable.
As a further scheme of the invention, for determining the risk classification risk level of the existing anti-smashing risk, triggering a crane PLC execution module to link with grab bucket control operation and warning personnel according to the risk classification result, the concrete steps are as follows:
When the authenticity of the anti-smashing risk is reliable, the safety distance is automatically adjusted according to the state of the grab bucket, wherein the calculation formula of the safety distance is D safe=k·(Vgrab·Tresp+Lgrab), D safe is the safety distance, k is the safety coefficient, V grab is the instantaneous speed of the grab bucket, T resp is the response time, and L grab is the projection length of the grab bucket;
And (3) classifying risk grades according to the safety distance, triggering a crane PLC execution module to link grab bucket control operation according to a risk grade classification result, and carrying out personnel warning.
As a further aspect of the invention, the safety factor k in the calculation formula of the safety distance is 1.2 when the grab is empty and 1.5 when the grab is full.
As a further scheme of the invention, the control operation of the crane PLC execution module linked grab bucket is triggered according to the risk classification result and the personnel warning is carried out, and the specific steps comprise:
triggering a first-level early warning when D safe<D1(τ)≤1.2Dsafe is carried out, and enabling staff to wear UWB bracelet to carry out vibration reminding at the moment;
when the speed of the AR glasses is 0.8D safe<D1(τ)≤Dsafe, triggering a secondary early warning, automatically decelerating the grab bucket at the moment, and displaying a red warning area as an unsafe area by the AR glasses worn by the personnel;
When D 1(τ)≤0.8Dsafe is carried out, triggering three-level early warning, hovering the grab bucket at the moment, and starting audible and visual warning.
A cabin worker anti-smashing system based on multi-sensor fusion comprises a sensing layer, a control layer, an interaction layer and a mechanical execution layer, wherein the sensing layer comprises a laser radar, a UWB positioning unit and a grab bucket state acquisition module;
The control layer comprises a region dividing module, an anti-smashing risk identification module, a risk authenticity checking module and a risk grade dividing module;
the interaction layer comprises UWB hand rings and AR glasses;
the mechanical execution layer comprises a crane PLC execution module.
As a further scheme of the invention, the laser radar is arranged on the arm support head and is used for scanning and acquiring the grab bucket movement track and the personnel movement track in real time;
The system comprises a UWB positioning unit, a grab bucket state acquisition module, a first positioning module, a second positioning module and a first positioning module, wherein the UWB positioning unit is used for comprising a positioning base station, a first positioning tag and a first positioning tag;
The region dividing module is used for acquiring the grab bucket movement track and the personnel movement track through laser radar real-time scanning, and dynamically dividing a safe region and a non-safe region according to the grab bucket movement track;
The anti-smashing risk identification module is used for carrying out anti-smashing risk identification on the personnel movement track in the unsafe area, and judging the anti-smashing risk according to the grab bucket movement track and the personnel movement track analysis track coincidence degree in the unsafe area;
the risk authenticity checking module is used for acquiring grab bucket movement signals and personnel movement signals based on the UWB positioning unit for unsafe areas with risk of smashing, combining grab bucket movement tracks in the unsafe areas with the grab bucket movement signals to check the first track matching degree, combining personnel movement tracks with the personnel movement signals to check the second track matching degree, and checking the authenticity of risk of smashing according to the first track matching degree and the second track matching degree;
The UWB bracelet is used for prompting personnel evacuation by vibration alarm;
The AR glasses are used for displaying the unsafe area as a red warning area;
the crane PLC execution module is used for controlling operation of the grab bucket in a linkage mode according to the risk grade division module and alarming personnel.
According to the invention, a safe area and a non-safe area are dynamically defined according to the grab bucket movement track and the personnel movement track, the personnel movement track in the non-safe area is subjected to anti-smashing risk identification, a grab bucket movement signal and a personnel movement signal are acquired based on a UWB positioning unit, the grab bucket movement track and the grab bucket movement signal in the non-safe area are combined and checked for a first track matching degree, the personnel movement track and the personnel movement signal are combined and checked for a second track matching degree, the authenticity of anti-smashing risk is checked according to the first track matching degree and the second track matching degree, and for determining the existing anti-smashing risk classification risk level, dynamic safety area demarcation, accurate risk identification, risk verification and grading intervention are realized through multi-sensor fusion, so that the safety of the ship cabin operation personnel is ensured.
According to the invention, through multi-sensor fusion, dynamic safety area, track coincidence analysis, UWB signal verification and risk grading linkage control, accurate anti-smashing protection of cabin operators is realized, the problem of high false alarm rate of a single sensor is solved, the reliability of the system in a severe environment is enhanced, and the comprehensive protection effect of combining early warning, real-time intervention and automatic risk avoidance is realized through a man-machine linkage control mechanism.
Detailed Description
The following description of the embodiments of the present invention will be made in detail, but not necessarily with reference to the accompanying drawings. Based on the technical scheme in the invention, all other technical schemes obtained by a person of ordinary skill in the art without making creative work fall within the protection scope of the invention.
As shown in fig. 1, a flowchart of a method for preventing a cabin worker from smashing based on multi-sensor fusion is provided in an embodiment of the present application, and an execution subject of the method shown in fig. 1 may be a software and/or hardware device. The execution body of the present application may include, but is not limited to, at least one of a user equipment, a network device, etc. The user device may include, but is not limited to, a computer, a smart phone, a Personal Digital Assistant (PDA), and the above-mentioned electronic device. The network device may include, but is not limited to, a single network server, a server group of multiple network servers, or a cloud of a large number of computers or network servers based on cloud computing, where cloud computing is one of distributed computing, and a super virtual computer consisting of a group of loosely coupled computers. This embodiment is not limited thereto. The method comprises the steps S1 to S4, and specifically comprises the following steps:
s1, acquiring a grab bucket movement track and a personnel movement track through laser radar real-time scanning, and dynamically defining a safe area and a non-safe area according to the grab bucket movement track;
S2, carrying out anti-smashing risk identification on the personnel movement track in the unsafe area, and judging the anti-smashing risk according to the grab bucket movement track and the personnel movement track in the unsafe area by analyzing the track coincidence degree;
S3, for the unsafe area with the risk of smashing prevention, acquiring grab bucket movement signals and personnel movement signals based on the UWB positioning unit, combining the grab bucket movement track in the unsafe area with the grab bucket movement signals to check the first track matching degree, combining the personnel movement track with the personnel movement signals to check the second track matching degree, and checking the authenticity of the risk of smashing prevention according to the first track matching degree and the second track matching degree;
And S4, for determining the risk classification risk level of the existing smashing prevention, triggering a crane PLC execution module to link the grab bucket to control operation and warning personnel according to the risk classification result.
Preferably, the motion trail of the grab bucket and the motion trail of the personnel are obtained through laser radar real-time scanning, and a safe area and a non-safe area are dynamically defined according to the motion trail of the grab bucket, and the method specifically comprises the following steps:
The method comprises the steps of scanning and collecting three-dimensional point clouds of a cabin operation area in real time through a laser radar, respectively identifying grab bucket targets and personnel targets through a point cloud clustering and tracking algorithm, respectively performing motion trail fitting based on the grab bucket targets and the personnel targets to obtain grab bucket motion trails and personnel motion trails, extracting first space motion characteristics based on the grab bucket motion trails, and extracting second space motion characteristics based on the personnel motion trails, wherein the space motion characteristics comprise speed characteristics and acceleration characteristics;
and extracting the grab bucket movement track and the first space movement characteristic to dynamically define an unsafe area, and marking the area except the unsafe area of the cabin operation area as the safe area.
In the cabin operation process, laser radar equipment arranged at the hatch position is utilized to scan an operation area in real time, and three-dimensional point cloud information of the whole cabin operation environment is obtained. The point cloud data contains various target objects such as grab buckets, operators and cargoes. Different point cloud clusters are distinguished through a point cloud clustering algorithm, and a clustering result is dynamically identified and tracked by combining a target tracking algorithm, so that effective separation and identification of a grab bucket target and a personnel target are realized. And then, generating motion tracks of the identified grab bucket targets and the identified personnel targets along with time by using a fitting algorithm, so as to obtain the grab bucket motion track and the personnel motion track.
On the basis of track generation, the first space motion characteristics including speed characteristics and acceleration characteristics of the grab bucket in each time segment are further extracted from the grab bucket motion track, and the characteristics can accurately reflect the running state and possible future motion trend of the grab bucket. And likewise, extracting a second space motion characteristic for the motion trail of the personnel, and describing the moving speed and acceleration change condition of the personnel in the working area.
And then, dynamically defining an unsafe area, namely a dangerous space range which can be covered and influenced by the grab bucket in a short time by taking the grab bucket movement track and the corresponding first space movement characteristic as the basis and combining the running direction, the running speed and the projection range of the grab bucket. The unsafe area can be dynamically adjusted along with the real-time updating of the grab bucket movement track, and the real-time performance and accuracy of dangerous area division are ensured. The work area other than the safe area is automatically marked as a safe area for personnel activities and work. By the method, dynamic safety area division can be realized in a complex cabin operation environment, and potential collision or drop risk caused by grab bucket movement is avoided.
Preferably, the method comprises the steps of extracting a grab bucket movement track and a first space movement feature to dynamically define an unsafe region, wherein the specific steps are that a grab bucket movement track point gamma 1(t)=(x1(t),y1(t),z1 (t) at the moment t is obtained, wherein (x 1(t),y1(t),z1 (t)) is the position coordinate of the grab bucket mass center at the moment t, and the neighborhood of the grab bucket movement track is defined as omega 1(t)={(x,y,z)|||(x,y,z)-Γ1(t)||≤R(t)};R(t)=r0 +alpha v (t) +beta a (t);
wherein omega 1 (t) is the neighborhood of a grab bucket movement track point at the moment t, (x, y, z) is the three-dimensional coordinate of any point in a cabin operation area, R (t) is the neighborhood radius at the moment t, R 0 is the geometric reference radius, alpha is the velocity gain coefficient, v (t) is the velocity characteristic in the first space movement characteristic, beta is the acceleration gain coefficient, and a (t) is the acceleration characteristic in the first space movement characteristic;
predicting the grab bucket movement track in the sampling period delta T time period: Wherein Γ 1 (t+DeltaT) is the grab bucket movement track in the time period of the sampling period DeltaT;
Predicting unsafe areas based on grab bucket movement tracks in a sampling period delta T time period to obtain omega 1 (t+delta T), calculating each sampling period delta T to obtain corresponding unsafe areas, and performing intersection operation based on the corresponding unsafe areas and personnel movement tracks gamma 2(t)=(x2(t),y2(t),z2 (T)) to obtain R ns(t)=Ω1(t+ΔT)∩Γ2 (T);
R ns (T) is an intersection output result, omega 1 (t+DeltaT) is a corresponding unsafe region in a sampling period DeltaT time period, and Γ 2 (T) is a personnel movement track at the moment T;
and dynamically judging whether the personnel are in the unsafe area according to the intersection output result, if the intersection output result is not an empty set, judging that the personnel are in the unsafe area, and if the intersection output result is an empty set, judging that the personnel are in the safe area.
In the embodiment of the invention, in the cabin operation process, the barycenter position coordinate of the grab bucket is Γ 1(t)=(x1(t),y1(t),z1 (t) obtained through a laser radar at the time t. In order to evaluate the possible risk range of the grab, a dynamic neighborhood Ω 1 (t) needs to be established around this location point. The radius R (t) of the neighborhood is not a fixed value, but is adjusted in real time according to the geometric dimension R 0 of the grab and the motion state of the grab, for example, when the grab speed v (t) is higher, the radius of the neighborhood is increased to reflect the expansion of the potential danger zone of the grab at a high speed, and similarly, when the grab acceleration a (t) is higher, the radius is also increased. The omega 1 (t) thus defined reflects the dangerous area of the grab movement more realistically.
Then, during a sampling period DeltaT, the system predicts the next movement position of the grab, Γ 1 (t+DeltaT), the prediction formula taking into account the speed and acceleration of the grab, e.g. if the grab is falling at a speed of 2m/s and has a certain acceleration, then within DeltaT=0.5 s, the predicted Γ 1 (t+DeltaT) will be closer to the real trajectory than a pure linear extrapolation. Based on the predicted position, a corresponding unsafe region Ω 1 (t+Δt) is generated again, thereby forming a dangerous space that dynamically changes over time.
At the same time, the motion trail Γ 2(t)=(x2(t),y2(t),z2 (t)) of the person is also acquired in real time by the positioning system. For example, a worker is moving along the bulkhead, and the movement track point of the worker is continuously changed. The system calculates the intersection R ns (T) of Γ 2(t)=(x2(t),y2(t),z2 (T)) with the predicted unsafe region Ω 1 (t+Δt). If the intersection result is not empty, namely the personnel track point falls into the dangerous area predicted by the grab bucket, the system immediately judges that the personnel is in the unsafe area. For example, if a certain calculation result shows that a person will enter the falling path of the grab bucket after 1 second, the system will trigger the anti-smashing risk early warning immediately. Otherwise, if the intersection result is an empty set, the condition that the personnel moving range is not intersected with the grab bucket dangerous area is indicated, and the personnel is judged to be in a safe state without an alarm. According to the embodiment, through the grab bucket track prediction and dynamic unsafe area demarcation and combining the intersection judgment of the real-time tracks of the personnel, the false judgment caused by demarcation only depending on the static area can be effectively avoided, and the accuracy and the instantaneity of the anti-smashing early warning are obviously improved.
Preferably, the method for judging the risk of smashing comprises the following specific steps of:
if the person is in the unsafe area, acquiring the grab bucket movement track and the person movement track at the moment, and calculating the intersection proportion of the two movement tracks in a time window as the track overlap ratio, wherein the calculation formula is as follows:
Wherein eta ΔT is the track coincidence degree in the sampling period delta T time period, D 1(τ)=d(Γ1(τ),Γ2 (tau)) is the Euclidean distance between the grab bucket movement track and the personnel movement track at the moment tau, D th is a dangerous threshold, delta is an indication function, the output result of the meeting condition is 1, the output result of the non-meeting condition is 0,
In order that the moment distance between the grab bucket movement track and the personnel movement track is smaller than the accumulated duration of the dangerous threshold value in the time window [ T, t+delta T ];
And comparing the track overlap ratio with a preset threshold, if the track overlap ratio is greater than or equal to the preset threshold, primarily judging that the risk exists, and if the track overlap ratio is less than the preset threshold, primarily judging that the risk does not exist.
In actual cabin operation, after the system detects that the personnel track enters the unsafe area predicted by the grab bucket, the coincidence condition of the grab bucket movement track and the personnel movement track in a period of time is further analyzed. Assuming that the motion trajectory of the grab bucket centroid is Γ 1 (τ) and the motion trajectory of the person is Γ 2 (τ) within the time window [ T, t+Δt ], the system first calculates the euclidean distance D 1(τ)=d(Γ1(τ),Γ2 (τ) of both at each instant by time. For example, when the grab bucket approaches the bilge during the descent phase, and the personnel just enters the hatch work area, if the distance between the two at a plurality of moments τ is less than the danger threshold D th, the output of the indication function δ (D 1(τ)<dth) is 1, which indicates that there is a potential collision risk at that moment, and if the distance is greater than the threshold, the output is 0, which indicates that the moment is relatively safe.
Then, the system integrates the results of all the moments in the whole time window [ T, t+delta T ] to obtain the accumulated duration of the dangerous distance state between the grab bucket and the personnel, and divides the duration by the length delta T of the time window to obtain the track coincidence degree eta ΔT. For example, if the duration of the grab bucket to person distance less than the hazard threshold is 3 seconds within a predicted time window of 5 seconds, the trajectory overlap ratio is η ΔT =0.6.
Preferably, for an unsafe area with risk of smashing prevention, a grab bucket motion signal and a personnel motion signal are acquired based on a UWB positioning unit, a grab bucket motion track in the unsafe area is combined with the grab bucket motion signal to check a first track matching degree, the personnel motion track is combined with the personnel motion signal to check a second track matching degree, and authenticity of the risk of smashing prevention is checked according to the first track matching degree and the second track matching degree, and the method comprises the following specific steps of:
positioning base stations in the UWB positioning units are deployed at four corners of a cabin operation area, a first UWB signal is obtained through a first positioning tag on a personnel helmet, and a second UWB signal is obtained based on a second positioning tag on a grab bucket;
Respectively carrying out two-way distance measurement on the first positioning tag and the second positioning tag with four base stations, and calculating to obtain the distance from the first positioning tag to each base station as a first distance, and the distance from the second positioning tag to each base station as a second distance;
Transmitting the first distance and the second distance to a central positioning engine through a wired network;
the central positioning engine respectively calculates real-time three-dimensional coordinates of the grab bucket and real-time three-dimensional coordinates of a helmet wearer according to the first distance and the second distance by using a trilateration method, and takes the real-time three-dimensional coordinates of the grab bucket as grab bucket movement signals and the real-time three-dimensional coordinates of the helmet wearer as personnel movement signals;
acquiring a grab bucket movement track and a personnel movement track, calculating Euclidean distance between the grab bucket movement track and a grab bucket movement signal at the same moment in real time to serve as a first distance value, and calculating Euclidean distance between the personnel movement track and the personnel movement signal at the same moment to serve as a second distance value;
the first distance value and the second distance value are respectively compared with a preset distance threshold, if the first distance value is larger than or equal to the preset distance threshold, the authenticity of the anti-smashing risk is unreliable, if the first distance value is smaller than the preset distance threshold, the authenticity of the anti-smashing risk is reliable, if the second distance value is larger than or equal to the preset distance threshold, the authenticity of the anti-smashing risk is unreliable, and if the second distance value is smaller than the preset distance threshold, the authenticity of the anti-smashing risk is reliable.
In the embodiment of the invention, in a certain operation in the actual cabin operation process, the grab bucket falls down to take materials, a worker enters an unsafe area of the grab bucket, a grab bucket movement track and a personnel movement track are established through the laser radar, and the high track overlapping degree of the grab bucket movement track and the personnel movement track is judged, so that the risk of smashing prevention is primarily judged. To further verify the authenticity of the risk, the UWB positioning unit is activated for verification.
Four UWB base stations which are deployed in advance at four corners of the cabin start to work. The first positioning tag mounted on the helmet of the worker continuously transmits signals to the four base stations, and the system obtains a first distance from the tag to each base station through two-way ranging. Likewise, a second locating tag mounted on the grab bucket communicates with the base stations to obtain a second distance from each base station, and the data are transmitted to the central locating engine in real time through the wired network.
The central positioning engine calculates the first distance to obtain the three-dimensional coordinate of the worker at the moment by using a trilateration method, and calculates the second distance to obtain the three-dimensional coordinate of the grab bucket. Thus, the real-time position of the worker is defined as the personnel movement signal and the real-time position of the grapple is defined as the grapple movement signal.
Next, the motion trajectory of the grapple is compared with the real-time motion signal of the grapple. For example, at some point in time, the Euclidean distance between the predicted grapple position and the actual coordinates of the grapple measured by UWB is 0.15m, and the preset distance threshold is 0.3m. Since 0.15m is smaller than 0.3m, the predicted track of the grab bucket is highly matched with the actual motion, and the first track matching degree is reliable. Similarly, the system compares the worker's motion profile with the actual position of the person measured by the UWB. If the calculated Euclidean distance is 0.12m and is smaller than a preset threshold value of 0.3m, the fact that the movement track of the person is consistent with the actual signal height is indicated, and the second track matching degree is reliable.
When the first distance value and the second distance value are both smaller than the threshold value, the track information is considered to be highly matched with the UWB signal, namely the authenticity of the anti-smashing risk is reliable, the fact that the worker is in the dangerous area of the grab bucket falling is indicated, the real anti-smashing risk exists, and high-level early warning is immediately sent out and emergency linkage is triggered. If the deviation between the predicted track of the grab bucket and the actual signal is too large in a certain comparison, for example, the first distance value reaches 0.5m and is higher than the threshold value 0.3m, the track prediction is indicated to be possibly deviated, at the moment, the authenticity of the anti-smashing risk is in doubt, and the system marks the risk as unreliable and prompts to recheck.
By the mode, the motion trail of the grab bucket and the personnel can be calibrated by utilizing the real-time motion signals provided by the UWB positioning unit on the basis of preliminary risk judgment, so that the real-time performance and the reliability of final anti-smashing risk identification are ensured, and the situations of false alarm and missing report are avoided.
Preferably, for determining the risk classification risk level of the existing smashing prevention, triggering a crane PLC execution module to link grab bucket control operation and warning personnel according to the risk classification result, wherein the concrete steps are as follows:
When the authenticity of the anti-smashing risk is reliable, the safety distance is automatically adjusted according to the state of the grab bucket, the calculation formula of the safety distance is D safe=k·(Vgrab·Tresp+Lgrab), wherein D safe is the safety distance, k is the safety coefficient, V grab is the instantaneous speed of the grab bucket, T resp is the response time, L grab is the projection length of the grab bucket, wherein the safety coefficient k is 1.2 when the grab bucket is empty and 1.5 when the grab bucket is full, the risk grade is divided according to the safety distance, and the PLC execution module of the crane is triggered to link the grab bucket to control the operation and warn personnel according to the risk grade division result.
Preferably, triggering a crane PLC execution module to link grab bucket control operation and warn personnel according to a risk classification result, wherein the specific steps comprise:
triggering a first-level early warning when D safe<D1(τ)≤1.2Dsafe is carried out, and enabling staff to wear UWB bracelet to carry out vibration reminding at the moment;
When the speed of the AR glasses is 0.8D safe<D1(τ)≤Dsafe, triggering a secondary early warning, automatically decelerating the grab bucket at the moment, and displaying a red warning area as an unsafe area by the AR glasses worn by the personnel;
When D 1(τ)≤0.8Dsafe is carried out, triggering three-level early warning, hovering the grab bucket at the moment, and starting audible and visual warning.
In cabin operation, after the risk of smashing prevention is verified through laser radar and UWB combined positioning, risk grades are further classified according to states of the grab bucket and real-time motion parameters. At a certain moment, the grab bucket is in a full-load state, the system detects that the instantaneous speed of the grab bucket is 1.5m/s, the response time is set to be 0.8s, and the projection length of the grab bucket is 2.0m. Firstly, safety distance calculation is carried out according to a calculation formula of the safety distance, wherein the safety coefficient k=1.5 when the vehicle is fully loaded. Substituting data gives D safe =1.5· (1.5×0.8+2.0) =4.8 m, i.e. a safety distance of 4.8m.
The real-time relative distance D 1 (τ) of the grapple from the operator is then compared to the safety distance D safe. If the shortest distance between a worker and the grab bucket is monitored to be 5.2m and D safe<D1(τ)≤1.2Dsafe is met, namely, 4.8m <5.2m is less than or equal to 5.76m, the primary early warning is triggered. At this time, the UWB bracelet worn by the worker can vibrate to remind, and prompt personnel to pay attention to keeping a safe distance.
If the relative distance between the other worker and the grab bucket is shortened to 4.5m at a certain moment, and 0.8D safe<D1(τ)≤Dsafe is met, namely 3.84m <4.5m < 4.8m, the risk is judged to be increased to the second-level early warning. At this time, the grab bucket control system automatically performs a deceleration operation, and marks the unsafe area as a red warning area in the AR glasses worn by the worker, further enhancing warning.
If in extreme cases, a person suddenly enters the position right below the grab bucket and keeps a distance of 3.5m with the grab bucket, D 1(τ)≤0.8Dsafe is met, namely, the distance is less than or equal to 3.84m, and three-level early warning is triggered immediately. At the moment, the grab bucket can hover emergently, and meanwhile, the audible and visual alarm device is triggered, so that operators can sense danger and withdraw from a dangerous area at the first time, and the risk of smashing down accidents is reduced to the greatest extent.
A cabin worker smash-proof system based on multi-sensor fusion comprises a sensing layer, a control layer, an interaction layer and a mechanical execution layer:
The sensing layer comprises a laser radar, a UWB positioning unit and a grab bucket state acquisition module;
The control layer comprises a region dividing module, an anti-smashing risk identification module, a risk authenticity checking module and a risk grade dividing module;
the interaction layer comprises UWB hand rings and AR glasses;
the mechanical execution layer comprises a crane PLC execution module.
The system comprises a cantilever crane, a laser radar, a grab bucket state acquisition module, a PLC, a first positioning tag, a second positioning tag, a first UWB signal and a second UWB signal, wherein the laser radar is arranged at the head of the cantilever crane and used for scanning and acquiring the motion trail of the grab bucket and the motion trail of personnel in real time;
The region dividing module is used for acquiring the grab bucket movement track and the personnel movement track through laser radar real-time scanning, and dynamically dividing a safe region and a non-safe region according to the grab bucket movement track;
The anti-smashing risk identification module is used for carrying out anti-smashing risk identification on the personnel movement track in the unsafe area, and judging the anti-smashing risk according to the grab bucket movement track and the personnel movement track analysis track coincidence degree in the unsafe area;
the risk authenticity checking module is used for acquiring grab bucket movement signals and personnel movement signals based on the UWB positioning unit for unsafe areas with risk of smashing, combining grab bucket movement tracks in the unsafe areas with the grab bucket movement signals to check the first track matching degree, combining personnel movement tracks with the personnel movement signals to check the second track matching degree, and checking the authenticity of risk of smashing according to the first track matching degree and the second track matching degree;
The UWB bracelet is used for prompting personnel evacuation by vibration alarm;
The AR glasses are used for displaying the unsafe area as a red warning area;
the crane PLC execution module is used for controlling operation of the grab bucket in a linkage mode according to the risk grade division module and alarming personnel.
As shown in fig. 2, a system block diagram of a cabin worker smash-proof system based on multi-sensor fusion according to an embodiment of the present invention is correspondingly applicable to executing steps in the method embodiment shown in fig. 1, and its implementation principle and technical effects are similar, and are not repeated here.
By introducing the embodiment, the safety area and the non-safety area are dynamically defined according to the grab bucket movement track and the personnel movement track, the personnel movement track in the non-safety area is subjected to anti-smashing risk identification, the grab bucket movement signal and the personnel movement signal are obtained based on the UWB positioning unit, the grab bucket movement track in the non-safety area and the grab bucket movement signal are combined and checked to form a first track matching degree, the personnel movement track and the personnel movement signal are combined and checked to form a second track matching degree, the authenticity of the anti-smashing risk is checked according to the first track matching degree and the second track matching degree, and the dynamic safety area definition, accurate risk identification, risk verification and grading intervention are realized through multi-sensor fusion, so that the safety of cabin operation personnel is ensured.
According to the invention, through multi-sensor fusion, dynamic safety area, track coincidence analysis, UWB signal verification and risk grading linkage control, accurate anti-smashing protection of cabin operators is realized, the problem of high false alarm rate of a single sensor is solved, the reliability of the system in a severe environment is enhanced, and the comprehensive protection effect of combining early warning, real-time intervention and automatic risk avoidance is realized through a man-machine linkage control mechanism.
The foregoing is merely illustrative of the present application, and the present application is not limited thereto, and any person skilled in the art will readily recognize that variations or substitutions are within the scope of the present application.
Finally, the foregoing is merely illustrative of the preferred embodiments of the present invention and is not intended to limit the invention thereto, and any modifications, equivalents, improvements or the like made within the spirit and principles of the present invention are intended to be included within the scope of the present invention.