Active Anti-Collision System and Method for Four-Way Shuttle Vehicles with Combined Point-Line LiDAR

Abstract

Active anti-collision system for four-way shuttle vehicle with combined point-line lidar, including vehicle-mounted unit, combined point-line lidar device, lateral channel, longitudinal channel, and four-way shuttle vehicle; the data receiving ends of the vehicle-mounted controllers in the vehicle-mounted computing unit are all connected to 4 single-point lidars and 2 single-line lidars; its method includes the following steps: the single-point lidars installed on the four-way shuttle vehicle respectively obtain the high-position obstacle information in the front, rear, left, and right directions of the four-way shuttle vehicle, and the single-line lidar obtains the low-position obstacle point cloud information around the four-way shuttle vehicle and transmits it to the vehicle-mounted controller. The vehicle-mounted controller calculates the braking acceleration that the current four-way shuttle vehicle should take and outputs it by identifying the distance and speed information between the high-position and low-position obstacles and the vehicle itself, and applying the braking control strategy of the four-way shuttle vehicle; it has the characteristics of high ranging accuracy, stable speed measurement, 360° full coverage, and fast and smooth operation.

Description

Technical Field

[0001] The present invention belongs to the technical field of warehousing logistics, and particularly relates to an active anti-collision system and method for a four-way shuttle vehicle with a combined point-line lidar. Background Art

[0002] In the rapidly developing warehousing logistics industry, in order to improve warehousing efficiency and save warehousing costs, unmanned warehousing is an inevitable trend in the development of the logistics industry. In a shelf-type three-dimensional warehousing system, a four-way shuttle vehicle is an intelligent handling device integrating functions such as traveling in four directions (front, back, left, and right), in-situ rail change, automatic handling, intelligent monitoring, and traffic dynamic management. The four-way shuttle vehicle warehousing system installs high-precision guide rails on traditional shelves, enabling intelligent four-way shuttle vehicles to freely travel in the shelves. Some guide rails also have the functions of goods transportation and goods storage, greatly improving the utilization rate of warehousing space. The four-way shuttle vehicle can travel along the longitudinal or transverse track directions on the cross tracks, and can reach any designated cargo position on the connected tracks in the warehouse, adapting to various working environments, with free terminal scheduling to achieve fully automatic unmanned operation. The intelligent four-way shuttle vehicle is an important warehousing logistics transportation device. It is a channel and bridge connecting the operation area, the production site, and the storage area, and has the advantages of high automation, labor and time saving, convenient and fast operation, and improved operation efficiency.

[0003] The core functions of the four-way shuttle vehicle are the automatic handling and transportation of warehouse pallet goods, including automatic storage and retrieval, automatic lane and floor change, intelligent leveling, and automatic climbing. The main requirements for the driving actions of the four-way shuttle vehicle are as follows: 1) When the four-way shuttle vehicle is moving in a straight line, it can start and stop smoothly on the straight track. 2) When the four-way shuttle vehicle reaches the designated position (each cross track intersection and each cargo position), it can accurately position to ensure that the four-way shuttle vehicle does not exceed or fail to reach the designated position. 3) In order to ensure the operation safety of the four-way shuttle vehicle, it is necessary to detect obstacles in the driving area of the four-way vehicle and take braking measures for active anti-collision. The active anti-collision system of the four-way shuttle vehicle can not only improve the operation efficiency in abnormal situations but also ensure the safety of life and property. Therefore, the active anti-collision system of the four-way shuttle vehicle is an important issue in the warehousing system of the four-way shuttle vehicle.

[0004] Currently, the active anti-collision methods for warehousing shuttle vehicles mainly use technical devices such as millimeter-wave radar, laser, sonar, infrared, and cameras to automatically obtain the distance and speed between the vehicle and the obstacle, and then perform braking through the actuator. However, due to the low accuracy of millimeter-wave radar, sonar, infrared, and cameras in detecting obstacles, the active anti-collision effect is not good. Combining the characteristics of the four-way shuttle vehicle warehousing system, it is of great practical significance to develop an active anti-collision system that can not only actively prevent collisions with stationary (being stored or fallen) goods but also prevent collisions with other four-way shuttle vehicles that are in motion. Summary of the Invention

[0005] To overcome the deficiencies of the above-mentioned existing technologies, the purpose of the present invention is to provide an active anti-collision system and method for a four-way shuttle vehicle with a combined point-line lidar. Four single-point lidars installed on the four-way shuttle vehicle respectively obtain high-position obstacle information in the front, rear, left, and right directions of the four-way shuttle vehicle, and two single-line lidars obtain low-position obstacle point cloud information around the four-way shuttle vehicle and transmit it to the vehicle-mounted controller. The vehicle-mounted controller calculates the braking acceleration that the current four-way shuttle vehicle should take and outputs it by identifying the distance and speed information between the high-position and low-position obstacles and the vehicle itself, and applying the braking control strategy of the four-way shuttle vehicle. When solving the problem of abnormal collision during driving, it has the characteristics of high ranging accuracy, stable speed measurement, 360° full coverage, fast and smooth operation.

[0006] To achieve the above purpose, the technical solution adopted by the present invention is: an active anti-collision system for a four-way shuttle vehicle with a combined point-line lidar, including a vehicle-mounted unit, a combined point-line lidar device, a lateral channel, a longitudinal channel, and a four-way shuttle vehicle; the data receiving ends of the vehicle-mounted controller in the vehicle-mounted computing unit are all connected to four single-point lidars and two single-line lidars.

[0007] The four single-point lidars include single-point lidar one, single-point lidar two, single-point lidar three, and single-point lidar four; the two single-line lidars include single-line lidar one and single-line lidar two.

[0008] The four-way shuttle vehicle travels horizontally on the lateral channel and vertically on the longitudinal channel.

[0009] The single-point lidar one, single-point lidar two, single-point lidar three, and single-point lidar four are respectively installed on the front, rear, left, and right of the four-way shuttle vehicle, and respectively measure distances in the front, rear, left, and right directions. The inclination angles of the four single-point lidars in the vertical plane are 10° to 30°; the single-line lidar one and single-line lidar two are installed diagonally, respectively installed at the left front corner and the right rear corner of the four-way shuttle vehicle, and respectively measure distances on the horizontal plane.

[0010] The detection area one of the single-line lidar one on the lateral channel and the detection area two on the longitudinal channel; the detection area three of the single-line lidar two on the lateral channel and the detection area four on the longitudinal channel; the detection area one, detection area three, detection area two, and detection area four are respectively the drivable rectangular areas in the front, rear, left, and right driving directions of the four-way shuttle vehicle.

[0011] The data receiving end in the vehicle-mounted controller receives the obstacle scanning data sent by 4 single-point lidars and 2 single-line lidars. The algorithm program reads the data and performs data processing to obtain the obstacle distance and relative speed in the driving direction of the four-way shuttle vehicle. The active collision avoidance program calculates to obtain the braking acceleration of the four-way shuttle vehicle and outputs it.

[0012] A method for the active collision avoidance system of a four-way shuttle vehicle using a combined point-line lidar includes the following steps:

[0013] Step 1, a single-point lidar one, a single-point lidar two, a single-point lidar three, and a single-point lidar four are respectively set in the front, rear, left, and right of the four-way shuttle vehicle; a single-line lidar one and a single-line lidar two are respectively installed at the left front corner and the right rear corner of the four-way shuttle vehicle; the single-line lidar one and the single-line lidar two are installed diagonally.

[0014] Step 2, the ranging results received by the vehicle-mounted controller of the four-way shuttle vehicle from the 4 single-point lidars are respectively 、 、 and . Through the historical ranging results and the filtering algorithm, the relative speeds between the obstacles in the front, rear, left, and right directions and the four-way shuttle vehicle are respectively 、 、 and ; the obstacle distance information obtained by the vehicle-mounted controller of the four-way shuttle vehicle through the 2 single-line lidars are respectively 、 、 and . Through the historical ranging results and the filtering algorithm, the relative speeds between the obstacles in the front, rear, left, and right directions and the four-way shuttle vehicle are respectively 、 、 、 ;

[0015] Step 3, when the four-way shuttle vehicle travels forward, let , , , ; when the four-way shuttle vehicle travels backward, let , , , ; when the four-way shuttle vehicle travels left, let , , , ; when the four-way shuttle vehicle travels right, let , , , , denote the anti-collision buffer distance of the four-way shuttle vehicle as , and the braking acceleration calculated by the single-point laser is , and the braking acceleration calculated by the single-line laser is ; is the obstacle distance information obtained by the single-point lidar in the driving direction of the four-way shuttle vehicle (2); is the relative speed between the obstacle and the four-way shuttle vehicle (2) obtained by the single-point lidar in the driving direction of the four-way shuttle vehicle (2); is the obstacle distance information obtained by the single-line lidar in the driving direction of the four-way shuttle vehicle (2); is the relative speed between the obstacle and the four-way shuttle vehicle (2) obtained by the single-line lidar in the driving direction of the four-way shuttle vehicle (2).

[0016] When the four-way shuttle vehicle is in the unloaded state, the ranging results of single-point lidar one, single-point lidar two, single-point lidar three, and single-point lidar four do not participate in anti-collision braking. At this time, the braking acceleration output by the system is , when the four-way shuttle vehicle is in the loaded state, the ranging results of single-point lidar one, single-point lidar two, single-point lidar three, and single-point lidar four participate in anti-collision braking. At this time, the braking acceleration output by the system is ;

[0017] The processing method of the vehicle-mounted controller for obtaining obstacle distance information through the single-line lidar includes the following steps:

[0018] First, comprehensively obtain the point cloud data received by single-line lidar one and single-line lidar two as ; Then convert the point cloud data to the vehicle body coordinate system as point cloud ; Then Filter the point cloud data in detection area one, detection area three, detection area two, and detection area four to obtain the new point cloud data in each area , , and ; Finally, obtain the ranging results in the front, rear, left, and right directions of the four-way shuttle vehicle , , and , and output, where represents the abscissa, represents the ordinate, represents the number of coordinate points in the point cloud, is the body length of the four-way vehicle, It is the body width of the four-way vehicle, and the output formula is:

[0019] , .

[0020] The beneficial effects of the present invention are as follows:

[0021] Compared with obstacle ranging and speed measurement technologies such as millimeter-wave radar, sonar, infrared, and cameras, the ranging and speed measurement of the single-point lidar and single-line lidar used in this anti-collision system are stable and have high accuracy, and there will be no uneven vehicle braking or even collision accidents caused by unstable ranging and large errors.

[0022] In this positioning system, 4 single-point lidars can cover the high-position obstacles in the front, rear, left, and right directions of the four-way shuttle vehicle, and 2 single-line lidars installed diagonally can cover the low-position obstacles around 360° of the four-way shuttle vehicle. Therefore, this anti-collision system can cover the surrounding obstacle information of the four-way shuttle vehicle almost without dead angles.

[0023] This anti-collision system combines the advantages of laser ranging and the processing algorithm of lidar point cloud data, extracts stable and reliable obstacle information in the driving direction of the four-way shuttle vehicle, and uses the braking control strategy of the four-way shuttle vehicle. This anti-collision system can quickly and smoothly solve the abnormal collision problem during driving.

[0024] The hardware of this system includes a four-way shuttle vehicle and its operation shelf channel, 4 single-point lidars, 2 single-line lidars, and 1 controller. Among them, 4 single-point lidars are respectively installed in the front, rear, left, and right directions of the four-way shuttle vehicle, tilted upward vertically by about 10°, and 2 single-line lidars are installed diagonally on the four-way shuttle vehicle, and the scanning plane is parallel to the track plane. The program in the controller uses the single-point laser and single-line laser to obtain the information of stationary or moving obstacles in the driving direction of the four-way shuttle vehicle, including the distance and speed between the vehicle and the obstacles, and gives the braking control acceleration to avoid collisions. Description of the Drawings

[0025] Figure 1 It is the system principle block diagram of the present invention.

[0026] Figure 2 It is a schematic diagram of the four-way shuttle vehicle size and vehicle body coordinate system.

[0027] Figure 3 It is the top view of the hardware setting of the system of the present invention.

[0028] Figure 4 It is the side view of the hardware layout of the system of the present invention.

[0029] Figure 5 This is the algorithm flowchart for the single-line lidar of the present invention to obtain obstacle distance information.

[0030] Figure 6 The active anti-collision algorithm flowchart of the four-way shuttle vehicle with the combined point-line lidar of the present invention is as follows. Specific embodiments

[0031] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0032] The dimensions of the four-way shuttle vehicle and the definition of the vehicle body coordinate system are as Figure 2 shown. The length of the vehicle body is , the width is . The origin of the vehicle body coordinate system is located at the center point of the four-way shuttle vehicle. The axis is parallel to the long side of the vehicle, and the axis is parallel to the short side of the vehicle. The axis is determined by the right-hand rule. Without loss of generality, the top view of the hardware layout of the anti-collision system is as Figure 3 shown, and the side view is as Figure 4As shown. The system includes a transverse channel 101, a longitudinal channel 102, a four-way shuttle 2, 4 single-point laser radars 1 301, 2 single-point laser radars 302, 3 single-point laser radars 303 and 4 single-point laser radars 304, 2 single-line laser radars 1 401, 2 single-line laser radars 402 and a vehicle controller 5. Among them, the four-way shuttle 2 can travel transversely on the transverse channel 101, and the four-way shuttle 2 can travel longitudinally on the longitudinal channel 102. The 4 single-point laser radars include a single-point laser radar 1 301, a single-point laser radar 2 302, a single-point laser radar 3 303 and a single-point laser radar 4 304; the single-point laser radar 1 301, the single-point laser radar 2 302, the single-point laser radar 3 303 and the single-point laser radar 4 304 are respectively installed on the front, back, left and right of the four-way shuttle 2, and measure distance in the four directions of front, back, left and right, and their inclination angles in the vertical plane are about 10°. The two single-line laser radars include a single-line laser radar 1 401 and a single-line laser radar 2 402; the single-line laser radar 1 401 and the single-line laser radar 2 402 are installed diagonally, respectively installed at the left front corner and the right rear corner of the four-way shuttle 2, and respectively perform distance measurement on the horizontal plane. The single-line laser radar 1 401 has a detection area 1 4011 on the transverse channel 101 and a detection area 2 4012 on the longitudinal channel 102, and the single-line laser radar 2 402 has a detection area 3 4021 on the transverse channel 101 and a detection area 4 4022 on the longitudinal channel 102. The detection area 1 4011, the detection area 3 4021, the detection area 2 4012, and the detection area 4 4022 are respectively rectangular areas that can be driven in the four driving directions of the four-way shuttle, front, back, left, and right. The program in the on-board controller 5 receives the obstacle scanning data sent by four single-point laser radars 1 301, single-point laser radar 2 302, single-point laser radar 3 303, single-point laser radar 4 304 and two single-line laser radars 1 401 and single-line laser radar 2 402, and processes the data to obtain the obstacle distance and relative speed in the driving direction of the four-way shuttle 2, and calculates using the anti-collision strategy to obtain the braking acceleration of the four-way shuttle 2 and output it.

[0033] The onboard controller 5 of the four-way shuttle vehicle 2 receives the ranging results of four single-point laser radars 1 301, 2 302, 3 303 and 4 304, respectively. , , and , through the historical distance measurement results and filtering algorithm, the relative speeds between the obstacles in the four directions of front, back, left, and right and the four-way shuttle 2 can be calculated as , , and The onboard controller 5 of the four-way shuttle vehicle 2 receives the ranging results of two single-line laser radars 1 401 and 2 402 respectively. , , and , through the historical distance measurement results and filtering algorithm, the relative speeds between the obstacles in the four directions of front, back, left, and right and the four-way shuttle 2 can be calculated as , , , .

[0034] An algorithm flow of a single-line laser radar to obtain obstacle distance information is as follows: Figure 5 First, the point cloud data of the received single-line laser radars 1 401 and 2 402 are comprehensively obtained as follows: ; Then the point cloud data Convert to vehicle coordinate system Below is the point cloud ; then The point cloud data in the detection area 1 4011, the detection area 3 4021, the detection area 2 4012, and the detection area 4 4022 are filtered to obtain new point cloud data in each area. , , and ; Finally, obtain the distance measurement results of the four-way shuttle in the four directions of front, back, left, and right , , and , and output, where, , .

[0035] This patent discloses a four-way shuttle active collision avoidance algorithm process of a combined point-line laser radar. Figure 6 When the four-way shuttle 2 moves forward, , , , ; When the four-way shuttle 2 moves backward, , , , ; When the four-way shuttle 2 moves to the left, , , , ; When the four-way shuttle 2 moves to the right, , , , , denote the anti-collision buffer distance of the four-way shuttle vehicle 2 as . The braking acceleration calculated by the single-point laser is . The braking acceleration calculated by the single-line laser is , is the obstacle distance information obtained by the single-point lidar in the driving direction of the four-way shuttle vehicle (2); is the relative speed between the obstacle and the four-way shuttle vehicle (2) obtained by the single-point lidar in the driving direction of the four-way shuttle vehicle (2); is the obstacle distance information obtained by the single-line lidar in the driving direction of the four-way shuttle vehicle (2); is the relative speed between the obstacle and the four-way shuttle vehicle (2) obtained by the single-line lidar in the driving direction of the four-way shuttle vehicle (2);

[0036] When the four-way shuttle vehicle 2 is in the unloaded state, the ranging results of the single-point lidar one 301, single-point lidar two 302, single-point lidar three 303 and single-point lidar four 304 do not participate in anti-collision braking. At this time, the braking acceleration output by the system is ; when the four-way shuttle vehicle 2 is in the loaded state, the ranging results of the single-point lidar one 301, single-point lidar two 302, single-point lidar three 303 and single-point lidar four 304 participate in anti-collision braking. At this time, the braking acceleration output by the system is .

Claims

1. An active anti-collision system for a four-way shuttle vehicle with a combined point-line lidar, characterized in that, It includes a vehicle-mounted unit, a combined point-line lidar device, a lateral channel (101), a longitudinal channel (102), and a four-way shuttle vehicle (2); the data receiving ends of the vehicle-mounted controllers (5) in the vehicle-mounted computing unit are all connected to 4 single-point lidars and 2 single-line lidars; The 4 single-point lidars include single-point lidar one (301), single-point lidar two (302), single-point lidar three (303), and single-point lidar four (304); the 2 single-line lidars include single-line lidar one (401) and single-line lidar two (402); The four-way shuttle vehicle (2) travels horizontally on the lateral channel (101) and vertically on the longitudinal channel (102); The single-point lidar one (301), single-point lidar two (302), single-point lidar three (303), and single-point lidar four (304) are respectively installed on the front, rear, left, and right of the four-way shuttle vehicle (2), and perform ranging in the front, rear, left, and right directions respectively, and the tilt angles of the 4 single-point lidars in the vertical plane are 10° to 30°; the single-line lidar one (401) and the single-line lidar two (402) are installed diagonally, and are respectively installed at the front left corner and the rear right corner of the four-way shuttle vehicle (2), and perform ranging on the horizontal plane respectively; The detection area one (4011) of the single-line lidar one (401) on the lateral channel (101) and the detection area two (4012) on the longitudinal channel (102); the detection area two (4021) of the single-line lidar two (402) on the lateral channel (101) and the detection area (4022) on the longitudinal channel (102); the detection area one (4011), the detection area two (4021), the detection area three (4012), and the detection area three (4022) are respectively rectangular areas where the four-way shuttle vehicle can travel in the front, rear, left, and right driving directions; The data receiving module in the vehicle-mounted controller (5) receives the obstacle scanning data sent by the 4 single-point lidars and the 2 single-line lidars, the algorithm program reads and processes the data to obtain the obstacle distance and relative speed in the driving direction of the four-way shuttle vehicle (2), and the active collision avoidance program calculates to obtain the braking acceleration of the four-way shuttle vehicle (2) and outputs it.

2. Method for an active anti-collision system of a four-way shuttle vehicle using a combined point-line lidar, characterized in that, It includes the following steps: Step 1, single-point lidar one (301), single-point lidar two (302), single-point lidar three (303), and single-point lidar four (304) are respectively arranged in the front, rear, left, and right of the four-way shuttle vehicle (2); single-line lidar one (401) and single-line lidar two (402) are respectively installed at the front left corner and the rear right corner of the four-way shuttle vehicle (2); the single-line lidar one (401) and the single-line lidar two (402) are installed diagonally; Step 2: The vehicle-mounted controller (5) of the four-way shuttle vehicle (2) receives the ranging results of 4 single-point lidar sensors, which are d 301 , d 302 , d 303 and d 304 . Through the historical ranging results and filtering algorithm, the relative speeds between the obstacles in the front, rear, left, and right directions and the four-way shuttle vehicle (2) are calculated as v 301 , v 302 , v 303 and v 304 respectively. The vehicle-mounted controller (5) of the four-way shuttle vehicle (2) obtains the obstacle distance information through 2 single-line lidar sensors, which are d 4012 , d 4022 , d 4011 and d 4021 . Through the historical ranging results and filtering algorithm, the relative speeds between the obstacles in the front, rear, left, and right directions and the four-way shuttle vehicle (2) are calculated as v 4012 , v 4022 , v 4011 , v 4021 respectively; Step 3, when the four-way shuttle vehicle (2) travels forward, let d3 = d 301 , v3 = v 301 , d4 = d 4012 , v4 = v 4012 ; when the four-way shuttle vehicle (2) travels backward, let d3 = d 302 , v3 = v 302 , d4 = d 4022 , v4 = v 4022 ; when the four-way shuttle vehicle (2) travels leftward, let d3 = d 303 , v3 = v 303 , d4 = d 4011 , v4 = v 4011 ; when the four-way shuttle vehicle (2) travels rightward, let d3 = d 304 , v3 = v 304 , d4 = d 4021 , v4 = v 4021 , record the anti-collision buffer distance of the four-way shuttle vehicle (2) as d, and the braking acceleration calculated by the single-point laser is The braking acceleration calculated by the single-line laser is When the four-way shuttle vehicle (2) is in an unloaded state, the ranging results of the single-point lidar one (301), single-point lidar two (302), single-point lidar three (303) and single-point lidar four (304) do not participate in anti-collision braking. At this time, the braking acceleration output by the system is a = a4. When the four-way shuttle vehicle (2) is in a loaded state, the ranging results of the single-point lidar one (301), single-point lidar two (302), single-point lidar three (303) and single-point lidar four (304) participate in anti-collision braking. At this time, the braking acceleration output by the system is a = min(a3, a4); The method for processing the obstacle distance information obtained by the on-vehicle controller (5) through the single-line lidar includes the following steps: First, comprehensively obtain the point cloud data of the single-line lidar one (401) and the single-line lidar two (402) received as Ω0 = {(x i , y i )} (i = 1, 2, …, N); then convert the point cloud data Ω0 to the vehicle body coordinate system OXY to obtain the point cloud Ω1 = {(x i ′, y i ′)} (i = 1, 2, …, N); then filter the point cloud data of Ω1 in the detection area one (4011), the detection area two (4021), the detection area three (4012), and the detection area four (4022) to obtain the new point cloud data Ω 4012 , Ω 4022 , Ω 4011 , and Ω 4021 ; finally, obtain the ranging results d 4012 , d 4022 , d 4011 , and d 4021 in the front, rear, left, and right directions of the four-way shuttle vehicle and output them. Among them, x represents the abscissa, y represents the ordinate, N represents the number of coordinate points in the point cloud, L is the body length of the four-way vehicle, and W is the body width of the four-way vehicle. The output formula is:

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