CN115158372A

CN115158372A - Large shuttle vehicle obstacle avoidance early warning method based on sound waves

Info

Publication number: CN115158372A
Application number: CN202210841342.0A
Authority: CN
Inventors: 蒲德全; 高振刚; 李鹏洲
Original assignee: Inner Mongolia University of Technology; Ordos Institute of Technology
Current assignee: Inner Mongolia University of Technology; Ordos Institute of Technology
Priority date: 2022-07-18
Filing date: 2022-07-18
Publication date: 2022-10-11
Anticipated expiration: 2042-07-18
Also published as: CN115158372B

Abstract

The invention relates to the field of vehicle safety control, in particular to a large shuttle vehicle obstacle avoidance early warning method based on sound waves. The method is applied to large shuttle cars or mechanical equipment, and is used for providing guidance for drivers and assisting the drivers to realize omnibearing obstacle avoidance in the driving process. The large shuttle vehicle obstacle avoidance early warning method comprises the following steps: s1: and radar echo signals in multiple directions around the shuttle car are collected. S2: and analyzing the obstacle distribution state of the shuttle car in the circumferential direction according to the acquired radar echo signals. S3: and generating a self-defined obstacle distribution state signal based on the obstacle distribution state. S4: each obstacle distribution state signal is matched with a section of simulated sound signal in real time. S5: ambient sound is eliminated through a stereo earphone worn by a user, and sound waves with an obstacle avoidance guiding effect are generated in the ear canal of the user according to the simulated sound signals. The invention solves the problems of large blind area range of large shuttle cars or machines, high driving difficulty and easy occurrence of collision accidents.

Description

Large shuttle vehicle obstacle avoidance early warning method based on sound waves

Technical Field

The invention relates to the field of vehicle safety control, in particular to a large shuttle vehicle obstacle avoidance early warning method based on sound waves.

Background

The shuttle car is a large mining equipment vehicle, the equipment vehicle is bulky, and a cab of the vehicle is positioned on one side of the vehicle, so that a driver in the vehicle has a large blind area. The mining area environment is complicated, and vehicle and personnel are intensive, and the driver blind area is great, and these all lead to shuttle car in the probability greatly increased that the use takes place the collision accident. The shuttle vehicle has large equipment dead weight and vehicle inertia, and is easy to generate large loss when collision occurs.

For example, when the shuttle car is used for loading coal at the continuous miner, in order to ensure no coal drop and maximum loading capacity, the coal receiving slot of the shuttle car needs to extend into the lower end of the coal unloading slot of the continuous miner, the cab and the coal receiving slot are arranged at two ends of the body of the shuttle car, and the bottom end of the coal receiving slot of the shuttle car is collided with the body of the continuous miner regularly according to the experience of a driver when the coal is received. When the shuttle car runs in a roadway, the shuttle car often collides with the coal wall of the roadway and other operating equipment in the roadway due to the fact that the size of the car body is large, the light intensity in the roadway is different, and the shuttle car is influenced by severe working conditions such as large dust on a tunneling working surface. These common collision accidents easily damage the anchor rods, the metal mesh and other equipment on the coal wall of the working face, and even injure the working personnel. When the shuttle car unloads coal at the transfer crusher, the coal unloading groove of the shuttle car is easy to collide with the crusher body. Furthermore, monotonous repetition of driving work, fatigue state of shuttle car driver in work, inattention and other human factors are also main causes of increasing the shuttle car collision probability and causing loss.

The addition of an obstacle avoidance system is a feasible technical means for solving the problems, but the shuttle vehicle has huge equipment and complex working environment; the driver needs to observe the traffic environment and the equipment working state in multiple directions at the same time. Various obstacle avoidance systems based on radar or cameras used in conventional small-sized vehicles cannot be effectively applied to the shuttle car equipment for mines, and even can cause interference to the operation process of drivers. In addition, the large equipment in the mine area is numerous, the environment is noisy, and conventional collisions and warnings are difficult to detect by drivers, which may cause more serious accidents.

Disclosure of Invention

Based on the technical scheme, the problems that a large shuttle car or engineering machinery has a large blind area range, high driving difficulty and is easy to cause collision accidents need to be solved; the large shuttle vehicle obstacle avoidance early warning method based on the sound waves is provided.

The technical scheme provided by the invention is as follows:

a large shuttle vehicle obstacle avoidance early warning method based on sound waves is applied to large engineering vehicles or mechanical equipment, and is used for providing guidance for drivers and assisting the drivers to achieve all-dimensional obstacle avoidance in the driving process. The large shuttle vehicle obstacle avoidance early warning method comprises the following steps:

s1: and transmitting detection signals to a plurality of directions around the shuttle car through the vehicle-mounted radar, and collecting radar echo signals in the plurality of directions around the shuttle car.

S2: and analyzing the peripheral obstacle distribution state of the shuttle car according to the acquired radar echo signals. The method specifically comprises the following steps: whether obstacles exist in each subarea or not, and the minimum distance and relative movement trend of the obstacles and the shuttle car.

S3: and generating a self-defined obstacle distribution state signal based on the obstacle distribution state. The state variables in the obstacle distribution status signal include zone markers, and an obstacle marker, an alert level marker, and a motion status marker corresponding to each zone.

S4: and querying an audio database by using the dynamically updated obstacle distribution state signals, matching a section of simulated sound signal for each obstacle distribution state signal in real time, and transmitting the simulated sound signals to a stereo headset worn by a user.

S5: ambient sound is eliminated through a stereo earphone worn by a user, and sound waves with the following characteristics are generated in the ear canal of the user according to the simulated sound signals:

(1) One or more buzzes corresponding to the number of obstacles exist in the sound field of the simulated sound signal.

(2) The distribution position of the buzzing sound in the sound field corresponds to the relative position of the obstacle and the shuttle car in the obstacle distribution state.

(3) The frequency of the buzzing sound is positively correlated with the distance between the obstacle and the shuttle car, and the frequency of the buzzing sound is higher as the distance is shorter.

(4) The intermittent state of the buzzing sound and the relative position of the obstacle and the shuttle car are related to: when the barrier is relatively close to the shuttle car, the buzzing sound is continuous and the frequency is gradually increased. The beep sound is interrupted when the obstacle is relatively far away from the shuttle car. The beep sound continues and maintains the current frequency when the obstacle and shuttle car are relatively stationary.

As a further improvement of the present invention, in step S1, the area in the circumferential direction of the shuttle car is divided into a plurality of different divisions according to the contour of the shuttle car. The number of the vehicle-mounted radars is multiple, and each subarea comprises at least two radars, so that the distance and the direction of the barrier in the subarea relative to the shuttle car can be calculated conveniently by using a triangulation method.

As a further improvement of the invention, the vehicle-mounted radar adopts any one of ultrasonic radar, microwave radar, millimeter wave radar and laser radar.

As a further improvement of the present invention, in step S2, the calculation formula of the minimum distance d between the obstacle and the shuttle car is as follows:

in the above formula, a represents the distance of the obstacle detected by the radar a in the current subarea; b represents the distance of the obstacle detected by the radar B in the current subarea; c represents the distance between the installation positions of the radar A and the radar B; α represents a deflection angle of a line connecting the obstacle and the radar a with respect to a direction of a line connecting the radars a and B.

As a further improvement of the present invention, in step S2, the relative movement tendency of the obstacle and the shuttle car is judged by the following method:

(1) Obtaining distance values d1 and d2 calculated by signals of two adjacent radar scanning periods;

(2) When d1 is larger than d2, the obstacle is relatively close to the mining shuttle car; when d1 is less than d2, the obstacle is far away from the mining shuttle car; when d1= d2, the obstacle is relatively static with respect to the mining shuttle car.

As a further improvement of the present invention, in step S3, the section mark in the obstacle distribution state signal is used to characterize the section number around the shuttle car. The obstacle mark is used for representing whether an obstacle is detected in the current subarea, if so, the value is 1, and if not, the value is 0. The warning level mark is used for representing the number of the warning level of the area to which the barrier belongs in the current subarea, the warning level is divided into a safety area, an early warning area, a slow-moving area, a warning area and a danger area, and the values are 1, 2, 3, 4 and 5 respectively. The motion state mark is used for representing the relative motion state of the barrier and the shuttle car in the current subarea, the relative motion state is divided into a relatively close state, a relatively static state and a relatively far state, and the values are respectively 1, 2 and 3. And when no obstacle exists in any subarea, the warning level mark and the motion state mark corresponding to the subarea are 0.

As a further improvement of the present invention, in step S4, the audio database is a pre-collected audio signal material library. Each section of audio in the audio signal material library corresponds to a specific obstacle distribution state signal direction; there is a one-to-one mapping relationship between the two. Each section of audio in the audio signal material library is generated and collected in a sound field simulation mode and converted into a stereo digital audio signal.

As a further improvement of the present invention, the method for acquiring each piece of audio in the audio database in step S4 is as follows:

1. equipment layout:

the sound source and the audio acquisition equipment are arranged in a recording room. The relative positions of the sound source and the audio acquisition device when installed are matched with the relative positions of the radar and the cab in the shuttle car. Wherein, each sound source corresponds to a radar.

2. Sound field simulation:

and controlling each sound source to generate buzzing sounds with different frequencies according to the collision risk grade corresponding to each obstacle distribution state signal so as to obtain the required target sound field.

In the sound field simulation process, device coding of the sound source performing the manipulation is sequentially determined according to the partition marks. Controlling the on-off states of different sound sources according to the obstacle markers; adjusting the frequency of the buzzing sound emitted by the sound source according to the warning level mark; and adjusting the intermittent state of the buzzing sound according to the motion state mark.

3. Signal acquisition:

and traversing all the obstacle distribution state signals corresponding to the collision scenes in sequence to generate an early warning signal sound field corresponding to each obstacle distribution state signal. And sampling the sound according to a frequency more than two times higher than the highest frequency of the sound according to a Nerns specific principle to obtain audio sampling data with a plurality of sections of preset duration.

4. Signal processing:

and setting a quantization format, a sampling rate and a channel number, and performing quantization processing and coding on each section of audio sampling data to respectively obtain stereo metadata corresponding to each section of audio sampling data.

As a further improvement of the invention, the detailed process of the sound field simulation stage is as follows:

first, device encoding of each sound source performing a manipulation is determined according to the partition markers.

Next, a decision is made based on the obstacle markers as follows:

(1) And when the obstacle mark indicates that the obstacle exists, starting the sound source equipment.

(2) And when the obstacle mark indicates that the obstacle does not exist, turning off the sound source equipment.

Then, based on the alert level flag, the following decision is made:

(1) And when the warning level mark indicates that the current area is a safe area, the driving sound source keeps a silent state.

(2) When the warning level mark indicates that the current area is a warning area, the driving sound source rings at the frequency of 2 Hz.

(3) When the warning level mark represents that the current area is a slow moving area; the driver sound source rings at a frequency of 4 Hz.

(4) When the warning level mark represents that the current area is a warning area; the driver sound source rings at a frequency of 8Hz.

(5) When the warning level mark represents that the current area is a dangerous area; the driving sound source maintains the prolonged sounding state.

Finally, the following decision is made based on the motion state flag:

(1) When the shuttle car is relatively close to the obstacle, the warning level of the obstacle in the current subarea is kept to be adapted to the frequency of the buzzing sound generated by the sound source.

(2) When the shuttle car is relatively far away from the barrier, the sound source is switched to a silent state.

(3) When the shuttle car is relatively close to the obstacle, the sound source is kept to continuously sound at the current frequency.

As a further improvement of the present invention, in step S5, the stereo headphone worn by the user is selected to be a headphone or an in-ear headphone having a noise reduction function. The stereo headset also comprises a communication module, wherein the communication module is used for receiving voice signals sent by other people to the current user, and the voice signals are played through a loudspeaker of the stereo headset.

The large shuttle vehicle obstacle avoidance early warning method based on the sound waves has the following beneficial effects:

the early warning method provided by the invention replaces the traditional image data with the sound wave to guide the shuttle car to avoid the obstacle. In order to accurately transmit and convey various information such as obstacle positions and movement trends related to obstacle avoidance to a user, the sound wave of the buzzing sound is improved, so that the single buzzing sound wave can represent more complex information. In the present invention, the ringing or silent state of the beep can characterize whether there is an obstacle with a collision risk; the position of the buzzing sound in the sound field can represent the distribution position of the obstacles; the frequency change and the intermittent state of the buzzing sound can represent the movement trend of the barrier; the acoustic frequency of the beep may be indicative of the level of vigilance of the obstacle. Therefore, the invention can transmit the obstacle distribution condition of each position of the shuttle car in the circumferential direction to the driver through sound waves, and accurately transmit the relative information such as the movement trend, the distance and the like of the obstacle to the driver, thereby exerting good obstacle avoidance early warning and path guiding effects.

Compared with the sound wave early warning and the image early warning, the invention has at least the following advantages: 1. the implementation cost of the scheme is low, and the economic benefit is high. 2. More information can be transmitted to the user, and the transmission of the distance and the movement trend information is more intuitive. 3. The interference to the user can be reduced, and the user can obtain long-time 'monitoring' information without shifting the sight to observe the screen. 4. Meanwhile, the auditory sense and the visual sense of the user are utilized to avoid obstacles and control the shuttle car, so that the safety of the shuttle car in the driving process is improved.

Drawings

Fig. 1 is a flowchart illustrating steps of a grading early warning method for an omnidirectional obstacle of a mining shuttle vehicle according to embodiment 1 of the present invention.

Fig. 2 is a distribution diagram of radar detection range partitions in the circumferential direction of the shuttle car in embodiment 1 of the present invention.

Fig. 3 is a diagram illustrating a warning level distribution of a radar circumferential obstacle avoidance early warning region in embodiment 1 of the present invention.

Fig. 4 is a diagram showing the installation position of the radar in the circumferential direction of the mining shuttle car in embodiment 1 of the invention.

Fig. 5 is a schematic diagram of a radar triangulation method.

Fig. 6 is a schematic structural diagram of an omnidirectional obstacle grading early warning system of a mining shuttle car provided in embodiment 2 of the present invention.

Fig. 7 is a schematic diagram of module connection of an omnidirectional obstacle grading early warning system of a mine shuttle vehicle in embodiment 2 of the present invention.

Fig. 8 is a logic block diagram of an alarm signal or a release signal generation process in different states.

Fig. 9 is a flowchart illustrating steps of a large shuttle vehicle obstacle avoidance early warning method based on sound waves according to embodiment 3 of the present invention.

Fig. 10 is a flowchart illustrating steps of a method for collecting metadata in an audio database according to embodiment 3 of the present invention.

Fig. 11 is a system architecture diagram of a shuttle car obstacle avoidance early warning system based on stereo headphones according to embodiment 4 of the present invention.

Fig. 12 is a schematic block diagram of a sound unit in a stereo headphone according to embodiment 4 of the present invention.

Fig. 13 is a schematic diagram of module connection of a noise reduction part in a stereo headphone according to embodiment 4 of the present invention.

Fig. 14 is a system architecture diagram of the shuttle car obstacle avoidance early warning system when the early warning signal simulation module is used as a functional module in the controller.

Fig. 15 is a system architecture diagram of the shuttle car obstacle avoidance early warning system with the addition of a display module and a camera.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without making any creative effort based on the embodiments in the present invention, belong to the protection scope of the present invention.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "or/and" includes any and all combinations of one or more of the associated listed items.

Example 1

The embodiment provides a grading early warning method for an omnidirectional obstacle of a mining shuttle car, which can be used for independently analyzing collision risks around a large-scale mining shuttle car and sending early warning to technicians according to risk grades. And the driver is further assisted to drive the vehicle safely in a complex mining area environment, obstacles possibly existing in the mining area are avoided, and the safety of the vehicle is improved. As shown in fig. 1, the method provided by this embodiment mainly includes the following steps:

s1: and uniformly dividing the circumferential area of the vehicle according to the appearance structure of the mining shuttle car and the interference state of the radar.

In this embodiment, the shuttle car of the conventional "boat type" configuration, as shown in fig. 2, is generally configured as an elongated octagon. In order to ensure that no four corners exist in radar detection, the shuttle car is at least required to be circumferentially divided into 8 detection directions. In 8 detection directions, the two sides of the head and the tail of the vehicle are collision high-incidence areas of the shuttle vehicle, so that the two sides of the front end and the rear end of the vehicle need to be respectively detected to eliminate the observation dead angle of a driver.

Meanwhile, the middle of the vehicle body is difficult to actively collide with other targets, but is easy to be collided by other moving objects, and the area range in the middle of the vehicle body is obviously larger than other subareas; therefore, the present embodiment further divides the regions on the left and right sides of the vehicle body, and divides both the left and right sides into two sections.

Finally, in this embodiment, the area in the circumferential direction of the shuttle car for the mine is divided into the following 12 partitions, which specifically include: the front part of the vehicle head FL, the left part of the vehicle head FML, the right part of the vehicle head FMR, the front part of the right part of the vehicle head FR, the left rear part of the vehicle tail RL, the left part of the vehicle tail RML, the right part of the vehicle parking space RMR, the right rear part of the vehicle parking space RR, the front part of the left front part of the middle section FSL, the left rear part of the middle section RSL, the front part of the right front part of the middle section FSR and the right rear part of the middle section RSR.

S2: and setting a differentiated grading rule according to the collision probability of each subarea, and dividing different areas into different warning levels in each subarea according to the sequence from far to near from the vehicle. As shown in fig. 3, the divided alert levels include at most: the safety area (5 area), the early warning area (4 area), the slow-moving area (3 area), the warning area (2 area) and the danger area (1 area).

In the early warning process of the vehicle, the early warning conditions of different areas of the vehicle are inconsistent. For example, the left and right sides of the car head and the parking space are collision high-rise areas, so that the warning level at the position needs to be higher than other areas under the same distance; meanwhile, different levels of early warning should be sent to the driver for obstacles at different distances. For the left side and the right side of the vehicle, because the probability of collision is small, the early warning grades do not need to be excessively divided.

Based on the foregoing consideration, in the present embodiment, different warning region division standards are adopted for different zones of the vehicle, wherein for the regions (such as four corners of the vehicle) with higher collision risk and larger blind area range, the warning level division is finer, and the difference between the warning levels is relatively smaller. And for the area with smaller collision risk, the warning level can be divided more loosely.

Assuming a distance D from the edge of the shuttle car for the mine, the embodiment makes the following provisions for the alert levels of different zones according to the collision data of the vehicles in the practical application process:

for the four corner divisions FL, FR, RL and RR of the vehicle: the area with D larger than 60cm is a safe area. The area with the D being more than or equal to 60cm and more than 35cm is taken as a warning area. The area with D less than or equal to 35cm is a dangerous area.

For the divisions FML and FMR of the vehicle front side: the area with D larger than 100cm is a safe area. The area with the D more than 60cm being more than or equal to 100 is a slow moving area. The area with the D more than 30cm being more than or equal to 60cm is taken as a warning area. The area with D less than or equal to 30cm is a dangerous area.

For the partitions RML and RMR on the vehicle rear side: the area with D larger than 150cm is a safe area. The area with the D more than 100cm being more than or equal to 150 is an early warning area. The area with the D more than 60cm being more than or equal to 100 is a slow moving area. The area with the D more than 30cm being more than or equal to 60 is taken as a warning area. The area with D less than or equal to 30cm is a dangerous area.

For the partitions FSL, RSL, FSR, RSR on both sides of the vehicle: the area with D larger than 30cm is a safe area. The area with D less than or equal to 30cm is a dangerous area.

S3: a radar group for detecting a distance to an obstacle is installed in each of the partitions, and each of the radar groups includes at least two radar units installed at different positions. Each radar unit is used for synchronously scanning the areas in the subareas and calculating the distance from the obstacle to the edge of the mining shuttle car through synchronous detection signals acquired by two adjacent radar units.

In the embodiment, in order to realize omnidirectional monitoring and omnidirectional obstacle avoidance early warning of the vehicle, independent radar groups are respectively arranged in each partition. Each radar group comprises a plurality of radar units, and further, the detection signals of different radars can be utilized to comprehensively analyze the detailed coordinates of the obstacles. Meanwhile, the positioning accuracy is higher when the number of the radar units in the radar group is larger, but the cost is correspondingly increased. Therefore, in the practical application process. The number of radar units in a radar group can be reasonably configured according to specific application scenarios so as to achieve balance between economy and functionality.

In order to realize accurate positioning of obstacles in the partitions, two radar units are installed in each partition, and the distance of the obstacles can be accurately predicted through independent detection signals of the two radar units, so that the defect that a single radar is limited by the detection direction when detecting a large obstacle and is easy to generate obvious errors is avoided. Specifically, the detection orientation of each radar installed in the present embodiment is shown in fig. 4. The present embodiment does not limit the type of the radar unit, and any radar unit may be used as the detection device required in the present embodiment as long as the radar unit can detect an obstacle. Technical staff can combine detection precision and equipment cost to carry out the comprehensive consideration, specifically, the radar unit in the radar group of installing in every subregion can adopt any one in ultrasonic radar, microwave radar, millimeter wave radar, the laser radar.

S4: at least 8 cameras are arranged in the circumferential direction of the mining shuttle car; the 8 cameras respectively acquire images of the front, the back, the left, the right, the front left, the back left, the front right and the back right of the vehicle.

In this embodiment, the function of the camera is to acquire a real-time obstacle in the partition when an approaching obstacle exists in any one direction of the vehicle, and the real-time obstacle is used as reference information for assisting a driver in avoiding an obstacle. According to the embodiment, the cameras are arranged at the edge positions of the shuttle car for the mine. Considering that the view range of the camera is relatively wide, the camera of the embodiment is not used as a detection device for detecting the obstacle, and the obstacle does not need to be accurately positioned;

specifically, the viewing area of the front camera in this embodiment includes the subareas FML and FMR. The view area of the right rear camera comprises partitions RML and RMR; the viewing area of the right left azimuth camera comprises partitions FSL and RSL. The view area of the right-hand camera comprises subareas FSR and RSR. The viewing areas of the front left azimuth camera, the rear left azimuth camera, the front right azimuth camera and the rear right azimuth camera respectively correspond to the partitions FL, RL, FR and RR. The number of image heads installed is less than the number of radar groups installed.

S5: acquiring real-time detection signals of the radars in all the subareas, and carrying out triangular positioning on the obstacle by combining synchronous detection signals of two radars in the current subarea when the obstacle is detected in any subarea; the minimum distance d between the obstacle and the vehicle is calculated. And determining the relative movement trend of the obstacle and the vehicle according to the change trend of the minimum distance d.

When an obstacle exists in any one subarea of the vehicle, the distance between the obstacle and the vehicle can be determined through an echo signal of the radar. However, when the obstacle is close to the vehicle or the obstacle has a large volume, the volume cannot be ignored relative to the vehicle; the detection direction of the radar has a significant influence on the range detection of the obstacle. Considering that the detection result of a single radar is often not reliable enough, the embodiment performs synchronous detection on the same obstacle by reading a plurality of radar units, and calculates a more accurate obstacle distance by combining the echo signals of the radar units. The minimum distance between the obstacle and the vehicle is used as one index for early warning the running state of the vehicle in the later period. The detection process of the obstacle provided by the implementation is as follows:

and acquiring detection signals of all radars in the current subarea in the current scanning period. When any radar detects an obstacle in the current scanning period, the detection signal of the radar is used as a signal I. And then acquiring a detection signal of the radar closest to the radar position as a signal two. And constructing a triangle by taking the distance between the obstacles calculated in the first signal and the second signal and the distance between the installation positions of the two radars as side lengths, and recording the length of the height of the triangle in the connecting line direction of the two radars as the shortest distance d between the obstacle and the edge of the mining shuttle car. The obstacle locating process in this embodiment is described in detail below with reference to fig. 5:

(1) Assuming that an obstacle C in a certain partition is detected by the radars a and B at the same time, the obstacle distances B and a detected by the radars a and B are obtained first.

(2) And then calculating the equipment distance c of the two radars A and B according to the installation positions of the two radars A and B.

(3) The minimum distance d of the obstacle C to the edge of the shuttle car for the mine is calculated by:

where α represents the yaw angle of the line connecting the obstacle and radar a with respect to the edge of the radar mine shuttle.

The method for determining the relative movement trend of the vehicle in the embodiment comprises the following steps:

when any radar detects an obstacle in the current subarea range, the minimum distance values d1 and d2 calculated in two continuous scanning periods are obtained, and the following judgment is made:

(1) When d1 > d2, it indicates that the obstacle is relatively close to the mining shuttle car.

(2) When d1 < d2, the obstacle is relatively far away from the mining shuttle car.

(3) When d1= d2, the obstacle is relatively static with respect to the mining shuttle car.

S6: and judging the alert level of the barrier in the current subarea by combining the minimum distance d between the barrier and the vehicle in any subarea, and executing the following early warning decision according to the alert level and the relative movement trend of the barrier and the vehicle:

(1) When the obstacle is outside the safety zone, no obstacle warning is made.

(2) And when the barrier is positioned in the safety zone, starting a camera responsible for the current zone, and acquiring the dynamic image of the current zone.

(3) When the barrier is positioned in the early warning area and is relatively far away, the alarm is not sent out; when the obstacle is located in the early warning area and is relatively close to the early warning area, a four-level alarm is sent out through low-frequency buzzing sound in the corresponding direction of the cab.

(4) When the obstacle is located in the buffer area and is relatively far away from the buffer area, no alarm is given; when the obstacle is in the buffer zone and relatively close to the buffer zone, a three-level alarm is sent out through medium-frequency buzzing sound at the corresponding direction of the cab.

(5) When the barrier is positioned in the warning area and is relatively far away from the warning area, no alarm is given; when the barrier is positioned in the warning area and is relatively close to the warning area, a secondary alarm is sent out in the corresponding direction of the cab through high-frequency buzzing sound.

(6) When the barrier is located in the danger zone and is relatively far away, no alarm is given; when the obstacle is in the danger zone and relatively close to the danger zone, a primary alarm is sent out by continuous sound at the corresponding direction of the cab.

(7) When the obstacle and the mining shuttle vehicle are relatively static in the area of any warning level, the alarm state of the vehicle at the current stage is maintained.

Wherein, the buzzing sound is generated by each buzzer arranged in the cab, and the relative position of the buzzer in the ringing state corresponds to the relative position of the partition generating the alarm state; the frequency of the low-frequency buzzing sound of the buzzer is 2Hz, the frequency of the low-frequency buzzing sound is 4Hz, and the frequency of the low-frequency buzzing sound is 8Hz.

In this embodiment, the corresponding relationship between the division criteria of different warning areas and the early warning decision content is shown in the following table:

table 1: early warning state comparison table of omnidirectional obstacle grading early warning system of shuttle car for mine

In this embodiment, in order to drive different alarms to sound according to the direction of the obstacle and quickly acquire image data in the dangerous partition, a mapping relationship among the device identification numbers/MAC addresses of the radar group, the camera and the buzzer corresponding to each partition is particularly realized. When the system determines that any partition reaches an alarm state according to the detection signals of all the radar groups, the system inquires the cameras responsible for the corresponding partitions and/or the equipment identification numbers/MAC of the buzzers according to the warning levels, and adjusts the working states of the corresponding cameras and the buzzers according to the made early warning decision.

In the mapping relationship established in this embodiment, the radar groups and the partition numbers correspond to each other one to one. The buzzers correspond to the partition numbers one by one. Each partition number corresponds to one camera, and each camera corresponds to one or more partition numbers.

In the grading early warning method for the omnidirectional obstacle of the mining shuttle car, provided by the embodiment, the buzzing sound is used for providing early warning for a driver, and a plurality of buzzers are installed in different directions in a vehicle cab. When an obstacle with collision risk exists in any direction of the vehicle, a buzzer corresponding to the position of the obstacle is called to sound, and the driver is reminded of paying attention. Proficient drivers can quickly identify the position of the barrier according to the sound source direction of the buzzing sound and timely avoid the barrier.

In the grading early warning method provided by the embodiment, the distance and collision probability of the obstacle are prompted by using the frequency of the buzzing sound. When the distance between the obstacles is closer, the generated buzzing sound is about sharp; the driver can intuitively know the distance of the obstacle at the corresponding position of the vehicle according to the frequency of the buzzing sound. When the barrier reaches the dangerous area of the vehicle, a long sound is emitted to remind the driver of emergency braking. Avoiding collision.

In addition, the present embodiment suggests the movement tendency of the obstacle using the intermittent state and the frequency change of the buzzer sound. For example, when a vehicle is within the warning range but relatively far away from the vehicle, indicating that the risk of collision between the vehicle and the obstacle is being relieved, the buzzer alarm may cease to be issued. However, when a certain vehicle is within the low level warning range but the vehicle is approaching an obstacle, indicating that the risk of collision between the two is increasing, a higher level of warning should be issued. And when the vehicle and the obstacle stay in a certain area, if the obstacle is located in the warning area, giving out a pre-alarm, otherwise, giving out no alarm.

The early warning method provided by the embodiment adopts the warning sound to transmit all information of the obstacle, so that the early warning can be sent to the driver without influencing the driving operation of the driver. The driver does not need to make driving judgment by observing the rearview mirror and the image data, so that the driver can be ensured to be highly concentrated, and the driving safety is improved. Meanwhile, the scheme of the embodiment also provides the real-time image of the corresponding subarea for sending the alarm signal for the driver, so that the driver can conveniently observe the types of the obstacles with risks through the auxiliary image, and can accurately avoid the obstacles according to the different types of the obstacles.

Example 2

On the basis of the mining shuttle car omnidirectional obstacle grading method provided by the embodiment 1, the embodiment further provides a corresponding grading early warning system, and the system is installed on a vehicle and fused with a control system of the vehicle. In the running process of the vehicle, the hierarchical early warning system can collect and analyze environmental information around the vehicle, and when an obstacle enters the warning range of any one subarea of the mining shuttle vehicle, the hierarchical early warning system accurately pre-judges collision risks in all directions of the vehicle and sends accurate hierarchical early warning to a driver. As shown in fig. 6, the grading early warning system provided by this embodiment includes: the device comprises a plurality of radar groups, a plurality of cameras, a plurality of buzzer alarms, a display module and a processing module.

The scanning areas of all the radar groups cover all the circumferential areas of the shuttle car for the mine. Each radar group comprises at least two radar units which are installed at intervals along the circumferential direction of the mining shuttle car; the radar units in each radar group are used for detecting obstacles in the respectively responsible subarea. The radar unit in the radar group can adopt any one of ultrasonic radar, microwave radar, millimeter wave radar and laser radar.

The partitioning of the detection range of the radar group is combined with the appearance structure of the mining shuttle car and the interference state of the radar to carry out comprehensive evaluation and determination, and the radar group needs to meet the following optimization conditions in the design and installation process: (1) The detection range of each radar unit in each radar group can realize the comprehensive coverage in the corresponding subarea, (2) the detection range of all the radar groups comprises all the areas in the circumferential direction of the mining shuttle car; (3) On the basis of satisfying the conditions (1) and (2), the number of radar units is minimized.

In order to meet the optimization conditions, in the embodiment, the radar partition is required to be performed on the shuttle car for the mine firstly in the radar installation process, and the method for installing the radar and detecting the radar partition is as follows: (1) The outer contour of the shuttle car for the mine is fitted to an approximate polygon which comprises the largest enclosed area and has the least number of edges. (2) And taking the approximate polygon as the approximate outline of the shuttle car for the mine, and installing at least one group of radar groups on the edge of the shuttle car for the mine corresponding to each edge. (3) In the approximate contour, the intersection point of each edge is the separation point of the subarea, and the boundary of the adjacent subareas is obtained by radiating outwards along the separation point. (4) On the basis of the finished subareas, corresponding subareas in the direction of the side with higher collision probability or larger subarea range are refined into a plurality of subareas, and the number of installed radar groups is increased in the subareas.

Each camera is installed at the outside edge of mining shuttle car, and the region of framing of every camera corresponds a region of mining shuttle car circumference, and the scope of framing of all cameras covers all regions of mining shuttle car circumference. The camera is kept in a closed state in a normal state, and is switched into a working state when receiving an alarm signal sent by the processing module. In the hierarchical early warning system of omnidirectional obstacle, every camera department still is provided with at least one light filling lamp, and the light filling lamp keeps closing under conventional state, only opens in step with the camera that corresponds when receiving alarm signal.

The buzzer alarms are respectively arranged in different directions in the cab and correspond to the positions of all the subareas of the thunder detection range in the vehicle. Each buzzer alarm is used for generating buzzing sounds with different frequencies for representing different alarm states according to the received alarm signal and stopping alarming after receiving the release signal. The buzzer alarm in the embodiment adopts the audible and visual alarm, and the audible and visual alarm sends out buzzing sounds with different frequencies and generates stroboscopic light signals with different frequencies after receiving the alarm signal. The frequency of the low frequency beeps is 2Hz, the frequency of the medium frequency beeps is 4Hz, and the frequency of the high frequency beeps is 8Hz.

The display module is used for displaying video stream data acquired by the camera, and the displayed video stream data are image data of a subarea with an obstacle in an alert range. The function of the display module in this embodiment is similar to that of a conventional vehicle, but is different from that of a conventional vehicle. In this embodiment, when dangerous barriers all appear in a plurality of subareas of the vehicle, the display module needs to display the image data from different sources on the same screen, so that the driver can know the environmental conditions of the vehicle everywhere in time.

As shown in fig. 7, the processing module includes a radar signal acquisition unit, an obstacle identification unit, an alarm signal generation unit, a partition query unit, an image acquisition unit, and a feature labeling unit. The radar signal acquisition unit comprises a plurality of subunits, and each subunit is in communication connection with one of the radar groups so as to synchronously acquire the scanning signals of each radar group in a preset scanning period. The obstacle identification unit is used for identifying whether obstacles exist in each subarea according to the scanning signals of the radar group corresponding to each subarea and calculating the minimum distance between the obstacles and the edge of the mining shuttle car. And then determining the warning level of the area to which the current obstacle belongs according to the minimum distance and the grading rule of the partition with the obstacle. The alarm signal generating unit is used for automatically generating an alarm signal/release signal containing a subarea number according to the motion state of the obstacle in the areas with different warning levels, generating the alarm signal when the obstacle approaches, and generating the release signal when the obstacle moves away. The partition inquiry unit is used for receiving the alarm signal, inquiring a partition equipment comparison table through the partition number, and acquiring the equipment identification number/MAC address of the camera and the buzzer which are responsible for the current partition. And then forwarding the alarm signal/release signal to the corresponding camera and the buzzer according to the equipment identification number/MAC address. The image acquisition module comprises a plurality of subunits, and each subunit is in communication connection with one of the cameras so as to synchronously acquire video stream data acquired by each camera in an open state. The characteristic marking module is used for preprocessing the collected video stream data, recognizing obstacles contained in each frame of image by combining the distance information of the obstacles and the mining shuttle car and marking the obstacles in the image; the marked image is output to a display module. The obstacle recognition task in the feature labeling module can be completed through an image recognition model based on a neural network, an image recognition technology is a very mature technology, a large number of perfect solutions can be provided in the prior art, and details are not repeated in the embodiment.

In this embodiment, a mapping relationship between the device identification numbers/MAC addresses of the radar group, the camera, and the buzzer corresponding to each partition is established in the partition device comparison table. In the mapping relation, radar groups correspond to partition numbers one to one. The buzzers correspond to the partition numbers one by one. Each partition number corresponds to one camera, and each camera corresponds to one or more partition numbers.

In this embodiment, the method for generating the alarm signal/release signal by the alarm signal generating unit is shown in fig. 8, and includes the following steps:

(1) When the obstacle is outside the safe zone, no signal is generated.

(2) And when the barrier is positioned in the safety zone, generating an alarm signal for starting the camera of the current zone.

(3) When the obstacle is located in the early warning area and relatively far away, a release signal for turning off the buzzer alarm is generated. When the obstacle is positioned in the early warning area and is relatively close to the early warning area, an alarm signal for controlling the current partition buzzing alarm to emit low-frequency buzzing sound is generated.

(4) When the obstacle is located in the buffer zone and relatively far away, a release signal for turning off the buzzer alarm is generated. When the barrier is in the slow-moving area and is relatively close to the slow-moving area, an alarm signal for controlling the current partition buzzing alarm to emit an intermediate-frequency buzzing sound is generated.

(5) When the obstacle is located in the warning area and is relatively far away from the warning area, a releasing signal for closing the buzzer alarm is generated. When the barrier is positioned in the warning area and is relatively close to the warning area, an alarm signal for controlling the current partition buzzer alarm to emit high-frequency buzzing sound is generated.

(6) When the obstacle is located in the hazard zone and relatively far away, a release signal for turning off the buzzer alarm is generated. When the obstacle is in the dangerous area and relatively close to the dangerous area, an alarm signal for controlling the current partition buzzer alarm to emit continuous buzzing sound is generated.

(7) When the barrier and the mining shuttle car are relatively stationary in the area of any warning level, no signal is generated. At this time, the vehicle still maintains the amount warning state of the current zone.

In the present embodiment, the positioning of the obstacle by the radar group is mainly based on the principles of the helench formula and triangulation. The precise positioning of the obstacle and the process of determining the movement trend are described in detail in embodiment 1, and details of relevant interior parts are not repeated in this embodiment.

The omnidirectional obstacle grading early warning system provided by the embodiment and the control system of the vehicle run synchronously, and after the vehicle is started, the grading early warning system is automatically activated and started. And when the vehicle is closed, the grading early warning system is synchronously closed to operate.

A self-checking program runs in a processing module of the grading early warning system, and the self-checking program can perform equipment self-checking on components such as a camera, a radar unit, a display and a buzzer when the vehicle is started every time, and judges whether each component has a fault or is abnormal. When any one component is in fault or abnormal (such as damaged radar or blocked camera), the grading early warning system sends the fault state to a control system or a safety system of the vehicle. And a control system or a safety system of the vehicle sends out a fault alarm to a driver, and after the fault alarm is sent out, the fault alarm is eliminated only when a self-checking program detects that the fault or the abnormal state is relieved and a manual instruction sent out by a manager is received.

The following are specifically mentioned: in the embodiment, the omnidirectional obstacle grading early warning system and the control system or the safety system of the vehicle can realize information interaction. The early warning for representing the danger degree of the barrier is sent out by the omnidirectional barrier grading early warning system and used for reminding a driver of avoiding the barrier in time. And fault alarms for indicating equipment failure in the graded early warning system are generated by a control system or a safety system of the vehicle according to the inspection result of the self-inspection program. The grading early warning system sends the detection result of the self-checking program to a control system or a safety system of the vehicle.

Example 3

Based on the same technical concept as that of the embodiment 1, the embodiment further provides a large shuttle car obstacle avoidance early warning method based on sound waves. The method can also be applied to various conventional large-scale engineering vehicles or mechanical equipment, such as: mining shuttle cars, heavy platform trailers, port heavy transport vehicles, large special work vehicles, large gas transport vehicles, container straddle carriers, and the like.

The vehicle is characterized in that the vehicle body is huge, the cab is located on one side of the vehicle, and the driving process is wide in the blind area range of the vehicle. Therefore, when the vehicle is used, a special obstacle avoidance system is needed to assist a driver to observe the environmental state around the vehicle, so that the probability of collision of the vehicle in the driving process is reduced. Providing real-time monitoring images around the vehicle for drivers is an effective means for assisting the drivers to avoid obstacles. However, this method requires the driver to simultaneously observe a plurality of different monitoring screens to comprehensively study and judge the state around the vehicle, which may consume the driver's efforts, resulting in that the driver cannot concentrate on the vehicle operation. Meanwhile, the multiple synchronous monitoring pictures may cause interference to the driver, resulting in misjudgment of the driver.

The obstacle avoidance early warning method for the large shuttle car provided by the embodiment does not assist in obstacle avoidance through video pictures, but provides guidance for drivers by using sound waves. And then the auxiliary driver can realize omnibearing obstacle avoidance in the driving process, and the interference of information sent by the auxiliary obstacle avoidance system to the driving operation process of the driver is eliminated.

As shown in fig. 9, the obstacle avoidance early warning method for the large shuttle car provided in this embodiment includes the following steps:

s1: and transmitting detection signals to a plurality of directions around the vehicle through the vehicle-mounted radar, and collecting radar echo signals in the plurality of directions around the shuttle vehicle.

As in embodiments 1 and 2, the present embodiment also divides the region in the shuttle car circumferential direction into a plurality of different divisions according to the contour of the shuttle car. And each zone is configured with an independent monitoring radar. The method for dividing radar detection partitions is not described in detail in this embodiment.

In this embodiment, the number of the vehicle-mounted radars is multiple, and each subarea contains at least two radars, so that the distance and the direction of the barrier in the subarea relative to the shuttle car can be calculated conveniently by using a triangulation method. The vehicle-mounted radar can adopt any one of ultrasonic radar, microwave radar, millimeter wave radar and laser radar.

The detection signal transmitted by the radar can be reflected after contacting with the obstacle, and the radar can judge whether the obstacle exists in the detected subarea range after receiving the reflected echo signal. The number of radars in each partition is not less than two in the embodiment, and therefore obstacle positioning and ranging can be achieved through triangulation positioning. The principle of radar triangulation is described in detail in embodiment 1, and this embodiment is not described again. In this embodiment, only a calculation formula of the obstacle distance measurement is given, and a calculation formula of the minimum distance d between the obstacle and the shuttle car is as follows:

in the above formula, a represents the distance of the obstacle detected by the radar a in the current subarea; b represents the distance of the obstacle detected by the radar B in the current subarea; c represents the distance between the radar A and the installation position of the radar B; α represents a deflection angle of a line connecting the obstacle and the radar a with respect to a direction of a line connecting the radars a and B.

According to the change of the minimum distance between the obstacle and the shuttle car detected by the radar at different moments, the relative movement trend between the shuttle car and the obstacle can be analyzed, in the embodiment, the relative movement trend between the obstacle and the shuttle car is judged by the following method:

(1) The distance values d1 and d2 calculated from the signals of two adjacent radar scanning periods are obtained.

(2) When d1 is larger than d2, the obstacle is relatively close to the mining shuttle car; when d1 is less than d2, the obstacle is far away from the mining shuttle car; when d1= d2, the obstacle and the mining shuttle car are relatively static.

S3: and generating a self-defined obstacle distribution state signal based on the obstacle distribution state. The state variables in the obstacle distribution status signal include zone flags, and an obstacle flag, an alert level flag, and a motion status flag for each zone.

In this embodiment, the partition marks in the obstacle distribution state signal are used to represent partition numbers around the shuttle car, and the partition numbers correspond to positions of the shuttle car where the radar is installed one by one. The obstacle mark is used for representing whether an obstacle is detected in the current subarea, if so, the value is 1, and if not, the value is 0. When no obstacle exists in any subarea, namely the obstacle mark is 0, the warning level mark and the motion state mark corresponding to the subarea are also 0.

The warning level mark is used for representing the number of the warning level of the area of the barrier in the current subarea, and the warning level is divided into a safety area, an early warning area, a slow-moving area, a warning area and a danger area, and the values of the warning level mark are 1, 2, 3, 4 and 5 respectively. In accordance with the foregoing embodiment, in this embodiment, the rules for dividing the warning levels in different zones in the circumferential direction of the shuttle car may be manually set according to actual conditions. In addition, the warning level in this embodiment is divided into five levels, and in other embodiments, the grading of the warning level may also be adjusted according to a specific application scenario, for example, the grading is divided into three levels, four levels, or even two levels.

The motion state mark is used for representing the relative motion trend of the barrier and the shuttle car in the current subarea, the relative motion state is divided into relatively close, relatively static and relatively far, and the values are 1, 2 and 3 respectively.

The signal frame format of the customized obstacle distribution status signal in this embodiment is shown in the following table:

table 2: frame format of self-defined obstacle distribution state signal

As shown in the above table, each obstacle distribution state signal includes a start character and an end character, and between the start character and the end character, a partition mark ARE of each partition, an obstacle mark OBS in the partition, a warning level mark GoW in the partition, and a movement state mark TRD of an obstacle in the partition ARE sequentially included. When the processor receives the signal, the processor can determine which subareas (azimuths) of the shuttle car have the obstacles with collision risks according to the analysis content of the signal, and can analyze the distance range of the obstacles and the shuttle car (analysis GoW) and the relative motion trend of the obstacles and the shuttle car (analysis TRD). The information contained in the obstacle distribution state signal is key information for providing obstacle avoidance guidance for the driver in the later period.

The audio database in this embodiment is a pre-collected audio signal material library. Each section of audio in the audio signal material library corresponds to a specific barrier distribution state signal direction; there is a one-to-one mapping relationship between the two. Each section of audio in the audio signal material library is generated and collected in a sound field simulation mode and converted into a stereo digital audio signal. The digital audio signal is the desired simulated acoustic signal.

S5: the stereo headset worn by the user is used for eliminating the ambient sound, and in the embodiment, the stereo headset worn by the user selects a headset or an in-ear headset with a noise reduction function. The stereo headset also comprises a communication module, wherein the communication module is used for receiving voice signals sent by other people to the current user, and the voice signals are played through a loudspeaker of the stereo headset.

In particular, the stereo headset in the present embodiment may generate sound waves in the ear canal of the user from the received emulated sound signal, with the following characteristics:

(2) The distribution position of the buzzing sound in the sound field corresponds to the relative position of the barrier and the shuttle car in the barrier distribution state.

(3) The frequency of the buzzer is positively correlated with the distance between the obstacle and the shuttle car, and the closer the distance, the higher the frequency of the buzzer.

(4) The intermittent state of the buzzing sound and the relative position of the obstacle and the shuttle car are related to: when the barrier is relatively close to the shuttle car, the buzzing sound is continuous and the frequency is gradually increased. The beeping sound is interrupted when the barrier is relatively far from the shuttle car. The beep sound continues and maintains the current frequency when the obstacle and shuttle car are relatively stationary.

The implementation provides a large shuttle vehicle obstacle avoidance early warning method which mainly utilizes the ability of sound listening and position distinguishing of human ears to realize obstacle avoidance guidance. The sound is used for distinguishing the position: when a sound source in any direction of a human body produces sound, the loudness, frequency, reverberation effect and the like of the sound received by two ears of the human body are different. The auditory nerve of the human body can accurately recognize the direction of the sound source according to the difference of the sound signals received by the ears.

The technical scheme provided by the embodiment filters the environmental noise received by human ears through the earphone with the noise reduction function. Then, a stereo audio which dynamically changes along with the distribution state of the obstacles around the shuttle car is sent out to human ears; the stereo audio can simulate a sound field environment, in the sound field environment, a sound source is arranged at the positions corresponding to different directions of the shuttle car in the circumferential direction, the barrier of each sound source in the direction begins to sound, the sound frequency changes dynamically along with the distance between the barriers, and when the barriers are close to each other, the frequency of the sound emitted by the sound source is gradually increased. When the obstacle stops, the sound frequency of the sound source remains unchanged. When the barrier is far away, the sound sources are naturally stopped. Therefore, the driver can judge the distribution state of the obstacles around the shuttle car according to the ringing states of the sound sources in different directions, and judge the relative motion relationship between the obstacles and the shuttle car.

Through the sound field environment simulated by the stereo earphones, a driver can intuitively find the condition of the obstacle in any direction of the shuttle car. Because the scheme of the embodiment is that the obstacle avoidance guidance is carried out through sound waves, the auditory perception of people is directly utilized, the driver can feed back at the first time, and the shuttle car is operated according to the distribution condition of the obstacles. The user can grasp the conditions of the left side and the right side or the rear side of the shuttle car without doing a turn-back or rotation action, so the early warning method of the embodiment can not cause interference to the driving behavior of a driver; this further improves the safety of the shuttle car driving process.

In the actual application process, the loudness of the stereo audio subjected to the simulation processing can be dynamically adjusted by a driver according to needs, so that the driver can hear clearly and cannot damage the hearing.

In fact, the noise reduction earphone can protect the hearing of the driver, and the driver is prevented from working in a noisy environment for a long time and hearing damage is prevented. Meanwhile, the noise reduction earphone of the embodiment also reduces the interference of the environmental noise to the driver in the driving process; the problem that a driver cannot clearly hear the voice instruction sent by a commander in a noisy environment is solved.

The audio provided in the audio database and capable of simulating the sound field environment with directivity is a key for the embodiment to realize obstacle avoidance guidance. As shown in fig. 10, the method for acquiring each piece of audio in the audio database of this embodiment is as follows:

1. equipment layout:

the sound source and the audio acquisition equipment are arranged in a recording room. The relative positions of the sound source and the audio acquisition device when installed are matched with the relative positions of the radar and the cab in the shuttle car. Wherein, every sound source all corresponds to a radar.

2. Sound field simulation:

and controlling each sound source to generate buzzing sounds with different frequencies according to the collision risk level corresponding to each obstacle distribution state signal, and further obtaining the required target sound field.

During the sound field simulation, device encoding of the sound source performing the manipulation is determined in turn according to the zone markers. Controlling the on-off states of different sound sources according to the obstacle marks; adjusting the frequency of the buzzing sound emitted by the sound source according to the warning level mark; and adjusting the intermittent state of the buzzing sound according to the motion state mark.

In particular, the detailed procedure of the sound field simulation phase is as follows:

first, device encoding of each sound source performing a manipulation is determined according to the partition marks.

Secondly, the following decision is made according to the obstacle markers:

Then, based on the alert level flag, the following decision is made:

(3) When the warning level mark represents that the current area is a slow-moving area; the driver sound source rings at a frequency of 4 Hz.

(5) When the warning level mark represents that the current area is a dangerous area; the driver sound source remains in the prolonged sounding state.

Finally, the following decision is made based on the motion state flag:

(1) When the shuttle car is relatively close to the barrier, the warning level of the barrier in the current subarea is kept to be adapted to the frequency of the buzzing sound generated by the sound source.

3. Signal acquisition:

and traversing all the obstacle distribution state signals corresponding to the collision scenes in sequence to generate an early warning signal sound field corresponding to each obstacle distribution state signal. And sampling the sound according to a frequency more than two times higher than the highest frequency of the sound according to a Nees specific theory to obtain audio sampling data with multiple sections of preset duration.

4. Signal processing:

the quantization format, the sampling rate and the number of channels are set, in this embodiment, the quantization format is 16bit, the sampling rate is set to 44100, and the number of channels is set to 2. And quantizing and coding each section of audio sampling data to respectively obtain stereo metadata corresponding to each section of audio sampling data.

What needs to be additionally stated is that: the number of pieces of audio metadata collected in the present embodiment is limited, and corresponds to the obstacle distribution state signals, respectively. And each audio metadata collected is of a short duration (on the order of fractions of a second or seconds). Therefore, in order to guarantee the quality of the digital audio, the digital audio can be encoded in a lossless compression mode, and the data size is not too large.

In addition, although the duration of each piece of audio metadata is short in this embodiment, the system can dynamically update the obstacle distribution state signal along with the acquisition of the radar detection signal, and then select multiple pieces of audio metadata according to the change of the obstacle distribution state signal to splice into one continuous audio, thereby providing long-term obstacle avoidance guidance for the user.

It is to be emphasized that: this and other embodiments indicate that "beeps" are just one form of audio guided by sound waves. The use of a buzzer sound has many advantages, such as: the human ear is sensitive to monotonous sound similar to white noise, and can generate better reminding or warning effect. The buzzer generating equipment, such as a buzzer, is low in production cost, and suitable for popularization and application, and the like. However, in this or other embodiments, other types of alert tones may be substituted for the beep tone in this example, if there is a better choice.

Example 4

On the basis of the large shuttle car obstacle avoidance early warning method based on the sound waves provided by the embodiment 3, the embodiment provides a shuttle car obstacle avoidance early warning system based on the stereo earphones, the system is applied to a large shuttle car or other engineering vehicles and mechanical equipment, and the method as the embodiment 3 is adopted to provide guidance for a driver and assist the driver to realize obstacle avoidance in the driving process. Compared with the scheme of embodiment 1 or 2, the scheme of embodiment 3 or 4 can further eliminate the interference of the environmental noise to the driver to distinguish the direction of the obstacle through the buzzer sound.

Specifically, as shown in fig. 11, the shuttle car obstacle avoidance early warning system provided by this embodiment includes a radar module, a stereo headset, and a controller. The controller confirms the distribution condition of obstacles around the shuttle car according to the detection result of the radar module, then sends the analysis result to the stereo earphones, and drives the stereo earphones to send out stereo buzzing sound with the obstacle avoidance guidance effect. The stereo buzzing sound is a stereo signal, and the stereo signal comprises one or more groups of buzzing sounds corresponding to different directions. The position of the buzzing sound in the sound field is used for representing the position of the obstacle in the circumferential direction of the shuttle car. The signal frequency of the beep represents the distance of the barrier from the shuttle car. The signal interruption state of the buzzer sound represents the approaching or departing state of the obstacle.

The radar module comprises a plurality of radar units; each radar unit is used for transmitting detection signals to specific subareas around the shuttle car and calculating the nearest distance of obstacles in each subarea according to echo signals of the detection signals. The details of the installation of the radar and the division of the shuttle car detection partition have already been described in detail in embodiments 1 and 2, and are not described again in this embodiment.

The controller in this embodiment is a signal transmission hub and data processing center between the radar and stereo headphones. On one hand, the controller receives the detection result of the radar module and generates a self-defined obstacle distribution state signal according to the detection result of the radar module. And on the other hand, the obstacle distribution state signal is sent to the stereo earphone, so that the stereo earphone can generate required stereo buzzing sound conveniently. The details of the related content of the obstacle distribution status signal are described in embodiment 3, and are not described again in this embodiment.

The stereo headset is worn by a driver and used for sending sound signals to the driver according to the driving condition of the shuttle car so as to provide obstacle avoidance guidance for the driver. The stereo headphone in this embodiment includes a sound unit and an ear cup. As shown in fig. 12, the sound units on both sides of the earphone each include a feedback microphone, a noise reduction processing module, a primary sound source, a secondary sound source, an early warning signal simulation module, and a voice receiving module. The earphone of making an uproar that falls adopts to have ear muff headphone in this embodiment, and this earphone has the better effect of making an uproar and giving sound insulation of falling for in-ear headphone, is fit for using in noisy operational environment, and the ear muff itself is with regard to isolated ambient noise that can be fine, and then strengthens the noise reduction of earphone, promotes the user to the resolution effect of three-dimensional buzzing sound.

As shown in fig. 13, in the stereo headphone, the feed-back microphone is located inside the ear cup at a position corresponding to the ear canal of the driver. The feedback microphone is used for collecting the environment noise really received by the user. The noise reduction processing module uses various existing ANC circuits, and the functional module is used for converting the collected environmental noise into a digital signal from an analog signal and generating a noise reduction signal with opposite phase and similar amplitude and frequency. The noise reduction signal is then sent to a driver of a secondary sound source, which is configured to emit a corresponding noise reduction signal in accordance with the noise reduction signal. The noise reduction and the environmental noise are opposite in phase, so that energy of the noise reduction and the environmental noise are mutually cancelled in the human cochlea, and the listening of the environmental noise to a driver in work is effectively suppressed.

The early warning signal simulation module is used for generating a simulation sound signal according to the received obstacle distribution state signal. The voice receiving module is used for receiving voice command signals sent by managers or commanders. The main sound source is used for generating three-dimensional buzzing sound for simulating the distribution state of obstacles around the shuttle car according to the simulated sound signals. And/or generate speech uttered by an administrator or director.

It should be noted that, in the stereo headphone of this embodiment, the early warning signal simulation module includes an inquiry unit and a storage unit. The storage unit stores metadata (i.e., the audio database in embodiment 3) of the simulated acoustic signals corresponding to all the obstacle distribution state signals. And a mapping relation between the storage address of the metadata of the simulation signal and the obstacle distribution state signal in one-to-one correspondence is established in the query unit. After receiving an obstacle distribution state signal, the early warning signal simulation module firstly queries a storage address corresponding to the metadata through the query module, and then extracts the metadata of the simulated sound signal from the storage unit according to the storage address.

In this embodiment, the early warning signal simulation module is a part of the stereo headphone and is equivalent to a driver. However, in other embodiments, as shown in fig. 14, the warning signal simulation module may be a separate functional module or installed in the controller as a part of the controller. Namely: the controller completes the relevant content of the simulation sound signal extraction work, and directly sends the extraction result to the stereo earphone to drive the stereo earphone to generate the required sound wave. In this state, the function of the early warning signal simulation module is already realized by an independent function module, and the stereo headset is equivalent to a conventional noise reduction headset or a monitoring device with a noise reduction function in the existing market. At this time, technicians can install or connect corresponding early warning signal simulation modules on the conventional monitoring equipment to realize the same function and reduce the equipment cost.

In the stereo headphone of this embodiment, the feedback microphone, the noise reduction processing module, and the infrasound source constitute a noise reduction submodule. The shuttle car obstacle avoidance early warning system based on the stereo earphones and the shuttle car are started synchronously, and the noise reduction submodule is kept in a normally open state in the starting state of the shuttle car. In stereo headphones, the priority of the voice command signal is higher than the priority of the stereo beep. When the system also receives a voice command signal sent by an administrator in the process of generating the three-dimensional buzzing sound, the system reduces the loudness of the three-dimensional buzzing sound or stops the playing of the three-dimensional buzzing sound, and plays the voice sent by the administrator or the commander.

In this embodiment, controller and radar module are connected through the CAN bus, and then realize carrying out centralized management to each radar unit. The stereo earphone is connected with the controller through a coaxial audio cable in a wired mode or through Bluetooth in a wireless mode. The stereo headset includes a data interface or communication module for wired or wireless connection.

In another more optimized embodiment, as shown in fig. 15, the shuttle car obstacle avoidance early warning system provided in this embodiment further includes a camera and a display module.

The number of the cameras is a plurality of, and the cameras are respectively installed at different positions of the shuttle car in the circumferential direction. Each camera is used for acquiring image data in one or more partitions, and the cameras send the acquired image data to the controller. The controller is also used for decoding the image data and then sending the decoded image data to the display module. The display module is used for displaying the image data acquired by each camera in a split screen mode. The display module may or may not be part of the system. When the display module does not belong to the system, the system can call the original display module (such as a control screen in the shuttle car) of the shuttle car to display the corresponding image data.

Namely: in the optimized embodiment, the conventional image obstacle avoidance is used as a supplement of the scheme of the embodiment, and the driver can distinguish the distribution of the obstacles through the guided stereo buzzing sound. The driver may also observe the display to determine the specific type of obstacle that is created in each direction, without affecting the driver's driving safety, in order to make more rational driving decisions (e.g., the driver may sound the obstacle and then observe the display to see if it is a threat, and may choose to roll over if not for a shuttle car).

Correspondingly, after the display module and the cameras are added, the controller is also used for controlling the on-off state of the corresponding cameras of each partition. And when the corresponding barrier mark in any partition in the barrier distribution state signal generated by the controller is 1, starting a camera responsible for the corresponding partition, and acquiring the image data in the partition. And when the corresponding barrier mark in any partition in the barrier distribution state signal generated by the controller is 0, closing the camera responsible for the corresponding partition.

In this embodiment, the voice receiving module is actually a communication module, and the communication module may be a module related to an intercom that implements short-distance communication in an area, or a module related to voice communication implemented by using a mobile communication network or WIFI, and the functional module is mainly used for receiving a voice command signal sent by an administrator or a commander.

In addition, in order to realize bidirectional communication, a microphone can be arranged on the stereo headset; the communication module adopts a bidirectional communication module which can realize voice receiving and transmitting. In this case, the stereo headphone in this embodiment becomes a headset with more abundant functions. In other embodiments, the stereo headset may also adopt new products such as intelligent helmets with the same functions.

The above-mentioned embodiments only express one of the embodiments of the present invention, and the description thereof is more specific and detailed, but not to be construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present invention should be subject to the appended claims.

Claims

1. A large shuttle vehicle obstacle avoidance early warning method based on sound waves is applied to shuttle vehicles or other large engineering vehicles, is used for providing guidance for drivers and assisting the drivers to realize omnibearing obstacle avoidance in the driving process; the large shuttle vehicle obstacle avoidance early warning method is characterized by comprising the following steps:

s1: transmitting detection signals to a plurality of directions around the shuttle car through a vehicle-mounted radar, and collecting radar echo signals in the plurality of directions around the shuttle car;

s2: the method comprises the following steps of analyzing the peripheral obstacle distribution state of the shuttle car according to the collected radar echo signals, and specifically comprises the following steps: whether obstacles exist in each subarea or not, and the minimum distance and the relative movement trend of the obstacles and the shuttle car;

s3: generating a self-defined obstacle distribution state signal based on the obstacle distribution state; the state variables in the obstacle distribution state signal comprise subarea marks, and an obstacle mark, an alert level mark and a motion state mark corresponding to each subarea;

s4: inquiring an audio database by using the dynamically updated barrier distribution state signals, matching a section of simulated sound signal for each barrier distribution state signal in real time, and transmitting the simulated sound signals to a stereo headset worn by a user;

(1) One or more buzzing sounds corresponding to the number of the obstacles exist in the sound field of the simulated sound signals;

(2) The distribution position of the buzzing sound in the sound field corresponds to the relative position of the barrier and the shuttle car in the barrier distribution state;

(3) The frequency of the buzzing sound is positively correlated with the distance between the barrier and the shuttle car, and the closer the distance, the higher the frequency of the buzzing sound is;

(4) The intermittent state of the buzzing sound and the relative position of the obstacle and the shuttle car are related to: when the barrier is relatively close to the shuttle car, the buzzing sound is continuous and the frequency is gradually increased; the buzzing sound is interrupted when the barrier is relatively far away from the shuttle car; the beeping sound continues and maintains the current frequency when the barrier and shuttle are relatively stationary.

2. The large shuttle car obstacle avoidance early warning method based on the sound waves as claimed in claim 1, wherein: in the step S1, dividing a circumferential area of the shuttle car into a plurality of different subareas according to the outline of the shuttle car; the number of the vehicle-mounted radars is multiple, and each subarea comprises at least two radars, so that the distance and the direction of the barrier in the subarea relative to the shuttle car can be calculated conveniently by using a triangulation method.

3. The large shuttle car obstacle avoidance early warning method based on the sound wave as claimed in claim 2, characterized in that: the vehicle-mounted radar adopts any one of ultrasonic radar, microwave radar, millimeter wave radar and laser radar.

4. The large shuttle car obstacle avoidance early warning method based on the sound waves as claimed in claim 2, characterized in that: in step S2, a calculation formula of the minimum distance d between the obstacle and the shuttle car is as follows:

5. The large shuttle car obstacle avoidance early warning method based on the sound waves as claimed in claim 4, wherein: in step S2, the relative movement trend of the obstacle and the shuttle car is determined by the following method:

(2) When d1 is larger than d2, the obstacle is relatively close to the mining shuttle car; when d1 is less than d2, the obstacle is relatively far away from the mining shuttle car; when d1= d2, the obstacle is relatively static with respect to the mining shuttle car.

6. The large shuttle car obstacle avoidance early warning method based on the sound wave as claimed in claim 2, characterized in that: in the step S3, the partition marks in the obstacle distribution state signal are used for representing partition numbers around the shuttle car; the obstacle mark is used for representing whether an obstacle is detected in the current subarea, if so, the value is 1, otherwise, the value is 0; the warning level mark is used for representing the number of the warning level of the area to which the barrier belongs in the current subarea, and the warning level is divided into a safety area, an early warning area, a slow-moving area, a warning area and a danger area and takes the values of 1, 2, 3, 4 and 5; the motion state mark is used for representing the relative motion state of the barrier and the shuttle car in the current subarea, the relative motion state is divided into relatively close, relatively static and relatively far, and the values are 1, 2 and 3; and when no obstacle exists in any subarea, the warning level mark and the motion state mark corresponding to the subarea are 0.

7. The large shuttle car obstacle avoidance early warning method based on the sound waves as claimed in claim 6, wherein: in step S4, the audio database is a pre-collected audio signal material library; each section of audio in the audio signal material library corresponds to a specific barrier distribution state signal direction; the two have a one-to-one mapping relation; each section of audio in the audio signal material library is generated and collected in a sound field simulation mode and converted into a stereo digital audio signal.

8. The large shuttle car obstacle avoidance early warning method based on the sound wave as claimed in claim 7, wherein: the method for acquiring each section of audio in the audio database in step S4 is as follows:

1. equipment layout:

the sound source and the audio acquisition equipment are arranged in a recording room; the relative positions of the sound source and the audio acquisition equipment during installation are matched with the relative positions of a radar and a cab in the shuttle car; each sound source corresponds to one radar;

2. sound field simulation:

controlling each sound source to generate buzzing sounds with different frequencies according to the collision risk level corresponding to each barrier distribution state signal, and further obtaining a required target sound field;

in the sound field simulation process, determining equipment coding of a sound source for executing control according to the partition marks in sequence; controlling the on-off states of different sound sources according to the obstacle marks; adjusting the frequency of the buzzing sound emitted by the sound source according to the warning level mark; adjusting the intermittent state of the buzzing sound according to the motion state mark;

3. signal acquisition:

sequentially traversing barrier distribution state signals corresponding to all collision scenes to generate an early warning signal sound field corresponding to each barrier distribution state signal; sampling the sound according to a frequency which is more than two times higher than the highest frequency of the sound according to a Nees specific principle to obtain audio sampling data with a plurality of sections of preset duration;

4. signal processing:

9. The large shuttle car obstacle avoidance early warning method based on the sound waves as claimed in claim 8, characterized in that: the detailed process of the sound field simulation stage is as follows:

firstly, determining the equipment codes of all sound sources for executing the operation and control according to the zone marks;

next, a decision is made based on the obstacle markers as follows:

(1) When the obstacle mark represents the existence of the obstacle, starting sound source equipment;

(2) When the obstacle mark indicates that the obstacle does not exist, turning off the sound source equipment;

then, based on the alert level flag, the following decision is made:

(1) When the warning level mark represents that the current area is a safe area, the sound source is driven to keep a silent state;

(2) When the warning level mark represents that the current area is a warning area, the sound source is driven to sound at the frequency of 2 Hz;

(3) When the warning level mark represents that the current area is a slow moving area; then the driving sound source rings at the frequency of 4 Hz;

(4) When the warning level mark represents that the current area is a warning area; the sound source is driven to ring at the frequency of 8 Hz;

(5) When the warning level mark represents that the current area is a danger area; the driving sound source keeps the long-sounding state;

finally, the following decision is made based on the motion state flag:

(1) When the shuttle car is relatively close to the barrier, keeping the alert level of the barrier in the current subarea to be adapted to the frequency of the buzzing sound generated by the sound source;

(2) When the shuttle car is relatively far away from the barrier, the sound source is switched to a silent state;

10. The large shuttle car obstacle avoidance early warning method based on the sound waves as claimed in claim 1, wherein: in step S5, the stereo headphone worn by the user selects a headphone or an in-ear headphone with a noise reduction function, and the stereo headphone further includes a communication module, where the communication module is configured to receive a voice signal sent to the current user by another person, and the voice signal is played through a speaker of the stereo headphone.