CN114634133B

CN114634133B - Narrow roadway omnidirectional AGV (automatic guided vehicle) forklift and control method thereof

Info

Publication number: CN114634133B
Application number: CN202210532012.3A
Authority: CN
Inventors: 蔡传玉; 鲁旭升
Original assignee: Jiangsu Think Tank Intelligent Technology Co ltd
Current assignee: Jiangsu Think Tank Intelligent Technology Co ltd
Priority date: 2022-05-17
Filing date: 2022-05-17
Publication date: 2022-09-09
Anticipated expiration: 2042-05-17
Also published as: CN114634133A

Abstract

The application provides an omnidirectional AGV (automatic guided vehicle) forklift for a narrow roadway and a control method thereof. The method comprises the following steps: the device comprises a U-shaped vehicle body, an inverted F-shaped portal, power units driving the inverted F-shaped portal to move back and forth on the left side and the right side of the inverted F-shaped portal, a corresponding control unit, a top controller and a corresponding sensor group. This application is synthesized through the control unit and is coordinated the sensing signal between the sensor group, detects photoelectric detection fork point through the fork before the fork and whether hit tray or barrier, confirms the steady fork of goods through prong position detecting element and gets, through the fork hole of the single discernment tray of fork hole discernment, combines automobile body angle and position correction, and it is just to parallel with the tray fork hole when making the portal frame fork get, and the prong hits the tray leg when avoiding the fork to get and leads to the safety problem. The fork tooth hits the tray leg and leads to the safety problem when this application can avoid the fork to get in a flexible way, compares traditional fork truck AGV chassis location after not detecting and the position appearance adjustment and directly antedisplacement fork tooth fork gets the tray, the security when can improving the fork and get the tray.

Description

Narrow roadway omnidirectional AGV forklift and control method thereof

Technical Field

The application relates to the field of unmanned warehousing systems, in particular to a narrow roadway omnidirectional AGV forklift and a control method thereof.

Background

The modern warehousing industry is increasingly pursuing intensive storage, and the length of the roadway distance between warehouses and shelves with the same area determines the effective storage space in the whole warehouse, namely the total material storage amount of a warehouse system is influenced. Therefore, AGV forklifts that can fork and unload fast for narrow roadways are becoming increasingly popular with customers.

The mode is got to the whole antedisplacement fork of vehicle that generally adopts when traditional AGV fork truck gets goods, and fork truck body need earlier intervene by navigation positioning system and control whole car forward movement when getting, then can drive the prong fork and get the goods. In the process, the forward moving speed needs to be controlled to be slow in order to ensure the positioning accuracy, so that the aim of quickly taking and placing goods cannot be fulfilled.

The fork of installation prong among traditional AGV fork truck gets portal adopts is oil cylinder drive, and speed is slower during the antedisplacement, and speed is multistage speed, and speed operation is unstable, and control accuracy is poor, and the tray is got to unable accurate quick fork.

Whether the accurate position of unable discernment tray and tray when tray was got to traditional fork truck AGV fork incline, it is askew easily to hit the tray when the fork was got, has safe risk.

Disclosure of Invention

The application provides a narrow roadway omnidirectional AGV fork truck and a control method thereof aiming at the defects of the prior art, and the application detects and coordinates the inverted F-shaped portal frame of the AGV fork truck through various sensing devices so as to rapidly and accurately fork and take or put down goods, so that the operation efficiency of the fork truck is improved, and the storage operation safety is guaranteed. The technical scheme is specifically adopted in the application.

Firstly, in order to achieve the purpose, a control method of a narrow roadway omnidirectional AGV forklift is provided, wherein the narrow roadway omnidirectional AGV forklift is provided with a fork tooth position detection unit, a goods detection unit and a fork front detection photoelectric device, and the control method comprises the following steps: after the power is on, detecting and triggering a control unit to calibrate the coordinate position of the fork tooth according to the sensing signal of the fork tooth position detection unit; according to an interactive signal of the upper controller, after the fork tines are aligned with fork holes of the goods tray, the U-shaped vehicle body main body is kept static, and the control unit is triggered to drive the inverted-F-shaped gantry to move so as to fork and take down the goods tray; in the forward moving process of the inverted F-shaped gantry, under the condition that the goods detection unit is not triggered, the control unit is correspondingly triggered to control the fork teeth and the inverted F-shaped gantry to suddenly stop according to reflection signals of obstacles in front of the fork teeth, which are obtained by photoelectric detection in front of the fork; after the goods detecting unit is triggered, the control unit controls the inverted F-shaped portal frame to drive the fork teeth to retreat and retract.

Optionally, in any one of the above control methods for the narrow roadway omnidirectional AGV forklift, the control unit is provided with a first power shaft and a second power shaft respectively corresponding to the left and right operating states of the inverted F-shaped gantry, and a virtual shaft; the specific steps of detecting and triggering the control unit to calibrate the coordinate position of the fork tine by the control unit according to the sensing signal of the fork tine position detection unit comprise: firstly, driving the inverted F-shaped gantry to move to a trigger position of a fork tooth front limit detection proximity switch or a fork tooth rear limit detection proximity switch along a single direction, then driving the inverted F-shaped gantry to move to a trigger position of a fork tooth origin detection proximity switch along a gantry forward moving channel in an opposite direction, and setting a first power shaft and a second power shaft to calibrate the trigger position of the fork tooth origin detection proximity switch as an origin position respectively; the tine position detection unit is further configured to: and after the sensing signal of the proximity switch triggering position is detected to be limited and detected before the inverted F-shaped gantry moves to the fork teeth or after the fork teeth, the fork teeth and the inverted F-shaped gantry are controlled by the trigger control unit to be kept at the current coordinate position or move in the opposite direction.

Optionally, the method for controlling the narrow roadway omnidirectional AGV forklift includes the following steps: firstly, controlling the inverted F-shaped gantry to return to a trigger position of a prong origin detection proximity switch, and setting a first power shaft and a second power shaft to calibrate the trigger position of the prong origin detection proximity switch as an origin position respectively; then, sending corresponding position, speed, acceleration or deceleration control instructions to the virtual shaft according to the sensing signals of the sensor group and the interaction signals of the upper controller; and controlling the first power shaft and the second power shaft to drive the power units on the left side and the right side of the inverted F-shaped portal frame according to the control instruction of the virtual shaft according to the electronic gear ratio of 1:1 respectively, so that the inverted F-shaped portal frame moves along the portal frame advancing channel.

Simultaneously, for realizing above-mentioned purpose, this application still provides a narrow tunnel qxcomm technology AGV fork truck, and it includes: the left side and the right side of the U-shaped vehicle body main body are provided with carriages, and a gantry forward moving channel is formed between the carriages; the inverted F-shaped portal is arranged between the carriages on the left side and the right side, moves forwards or backwards relative to the U-shaped vehicle body main body along the portal advancing channel, and drives fork teeth on the front side of the inverted F-shaped portal to fork and take or put down the cargo tray; the left side and the right side of the inverted F-shaped gantry are respectively provided with a group of power units, the power units are connected with the control unit, and the inverted F-shaped gantry is correspondingly driven to drive the fork teeth to move along the gantry advancing channel in response to a control signal of the control unit; the control unit is also connected with a sensor group and an upper controller, and responds to a sensing signal of the sensor group and an interaction signal of the upper controller to correspondingly adjust a control signal output by the control unit; the upper controller is used for adjusting the position of the U-shaped vehicle body main body along a roadway according to the image of the fork hole of the cargo tray, keeping the U-shaped vehicle body main body static after the fork teeth are aligned with the fork hole of the cargo tray, and triggering the control unit to drive the inverted-F-shaped door frame to fork and take or put down the cargo tray.

Optionally, as described in any one of the above, the narrow roadway omnidirectional AGV forklift, wherein the sensor group includes: the front fork detection photoelectric sensor is arranged at the front end of the fork teeth and used for detecting obstacles in front of the fork teeth and correspondingly triggering the control unit to control the fork teeth to stop suddenly according to obstacle detection signals; the fork tooth position detection unit is arranged on the surface of the side wall of the carriage, is positioned between the carriages on the left side and the right side, and is used for detecting and triggering the control unit to calibrate the coordinate position of the fork tooth; the goods detection unit is arranged on the front side of the inverted-F portal frame, is positioned on the rear side of the fork teeth and is used for responding to the goods forking position to trigger the control unit to control the inverted-F portal frame to drive the fork teeth to retreat; the upper controller is connected with a fork hole identification unit, is arranged on the front side of the inverted F-shaped portal and located on the rear side of the fork teeth, and is used for identifying images of the fork holes of the cargo pallet to trigger the upper controller to drive the U-shaped vehicle body main body to correspondingly correct the angle and the position of the vehicle body according to the pallet fork holes.

Optionally, as for the narrow roadway omnidirectional AGV forklift, two sets of guide rails are horizontally arranged between the carriages on the left and right sides and on the edges of the upper and lower sides of the carriages respectively, and the upper and lower sides of the inverted F-shaped gantry are supported by the guide rails together and are limited to only slide in a front-and-back translational manner along the gantry forward moving channel; the fork tooth position detection unit comprises two groups of guide rails arranged between the upper guide rail and the lower guide rail respectively: the fork tooth front limit detection proximity switch is arranged at the front end of the guide track and used for detecting the position of the inverted-F-shaped gantry, and the fork tooth front limit detection proximity switch outputs a sensing signal to the control unit when being triggered by the inverted-F-shaped gantry, so that the control unit correspondingly adjusts the control signal to enable the fork tooth to retreat or keep the current coordinate position; the fork tooth rear limit detection proximity switch is arranged at the rear end of the guide track and used for detecting the position of the inverted-F-shaped gantry, and the fork tooth rear limit detection proximity switch outputs a sensing signal to the control unit when being triggered by the inverted-F-shaped gantry, so that the control unit correspondingly adjusts the control signal to enable the fork tooth to advance or keep at the current coordinate position; and the prong origin detection proximity switch is arranged between the prong front limit detection proximity switch and the prong rear limit detection proximity switch and is positioned at the position close to the prong rear limit detection proximity switch, and the prong origin detection proximity switch is used for detecting the position of the inverted F-shaped gantry, so that the control unit correspondingly takes the trigger position of the prong origin detection proximity switch as the coordinate origin position of the output control signal of the control unit.

Optionally, the narrow roadway omnidirectional AGV forklift as described in any one of the above, wherein the prong origin detection proximity switch on the left side car and the prong origin detection proximity switch on the right side car are symmetrical to each other, and a distance from the prong origin detection proximity switch on the left side car to the front end of the left side car is set to be consistent with a distance from the prong origin detection proximity switch on the right side car to the front end of the right side car; the control unit is provided with a first power shaft and a second power shaft which respectively correspond to the running states of the left side and the right side of the inverted F-shaped portal, and is also provided with a virtual shaft, and the control unit controls and drives the inverted F-shaped portal to move according to the following steps in the process of forking or putting down the goods tray at each time: firstly, controlling the inverted F-shaped gantry to return to a trigger position of a prong origin detection proximity switch, and setting a first power shaft and a second power shaft to calibrate the trigger position of the prong origin detection proximity switch as an origin position respectively; then, sending corresponding position, speed, acceleration or deceleration control instructions to the virtual shaft according to the sensing signals of the sensor group and the interaction signals of the upper controller; the first power shaft and the second power shaft respectively drive the power units on the left side and the right side of the inverted F-shaped portal frame according to the control instruction of the virtual shaft according to the electronic gear ratio of 1:1, so that the inverted F-shaped portal frame moves along the portal frame advancing channel.

Optionally, as described in any of the above narrow roadway omnidirectional AGV forklifts, the detection photoelectricity in front of the fork is respectively arranged at the front ends of the left and right fork tines, and is used for responding to a reflection signal of an obstacle in front of the fork tines in a state that the goods detection unit is not triggered in the forward moving process of the inverted F-shaped gantry, and correspondingly triggering the control unit to control the fork tines and the inverted F-shaped gantry to suddenly stop.

Optionally, as described in any one of the above narrow roadway omnidirectional AGV forklifts, the cargo detection unit is disposed on the front side of the inverted F-shaped gantry, is located on the rear side of the fork teeth, and is configured to respond to the cargo forking position and output a sensing signal to the control unit when being triggered by the contact of the cargo and/or the cargo pallet, so that the control unit controls the inverted F-shaped gantry to drive the fork teeth to retract backwards.

Optionally, as described in any one of the above, the narrow roadway omnidirectional AGV forklift, wherein the fork hole identification unit includes: the 3D camera is used for acquiring three-dimensional coordinates (X, Y, Z) of each pixel point of the goods tray fork hole image relative to a central point of the camera; an identification module configured to: firstly, extracting the outline of the tray fork hole surface and a corresponding distance image according to a preset pixel point amplitude value; calculating a tray picture width delta X1 according to the transverse width of the outline of the tray fork hole and the radial depth data in the distance image, comparing the difference value between the tray picture width delta X1 and the actual tray width L1, judging the tray inclination when the difference value exceeds a set standard, calculating the inclination offset, and correspondingly triggering an upper controller to drive the U-shaped vehicle body main body to correspondingly correct the angle and the position of the vehicle body according to the inclination offset; when the difference value does not exceed the set standard, the U-shaped vehicle body main body is kept static through the upper controller, and the control unit is triggered to drive the inverted F-shaped door frame to fork or put down the cargo tray.

Advantageous effects

The control unit is used for comprehensively coordinating sensing signals among the sensor groups, detecting whether a fork point collides with a tray or other obstacles through photoelectric detection before forking, determining stable forking and taking of goods through the fork point position detection unit, identifying a fork hole of the tray through the fork hole identification unit, and correcting the angle and the position of a vehicle body, so that the door frame fork is parallel to the fork hole of the tray when being taken, and the fork point is prevented from colliding with a tray leg to cause a safety problem when being taken. This application can realize getting the control of process down in a flexible way to the goods fork, and the prong hits the tray leg when avoiding the fork to get and leads to the safety problem, and this application is compared and is not detected and the position appearance adjustment and the mode that the tray was got to the fork prong that directly shifts forward after traditional fork truck AGV chassis location, and this application can improve the fork and get the security when tray.

Additional features and advantages of the application will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by the practice of the application.

Drawings

The accompanying drawings are included to provide a further understanding of the application and are incorporated in and constitute a part of this specification, illustrate embodiments of the application and together with the description serve to explain the principles of the application and not limit the application. In the drawings:

FIG. 1 is a schematic overall structure diagram of a narrow roadway omnidirectional AGV fork truck of the present application;

FIG. 2 is a schematic structural diagram of an inverted F-shaped gantry in a narrow roadway omnidirectional AGV fork truck according to the present application;

FIG. 3 is a rear view of the inverted F gantry of the present application;

FIG. 4 is a block diagram of a gantry control system of the present application;

FIG. 5 is a schematic view of the pallet fork hole identification scheme of the present application;

fig. 6 is a control flow schematic diagram of the narrow roadway omnidirectional AGV forklift of the present application.

In the figure, 101 denotes a left-side fork front detection photo-electricity; 102 represents the right side front fork detection photo; 103 left tine origin detection proximity switch; 104 for tine front limit detection proximity switches; 105 a tine rear limit detection proximity switch; 106 a cargo return striker detection travel switch; 107 denotes a 3D pallet fork hole recognition camera; 108 indicates a right tine origin detection proximity switch; 202 denotes a first motor; 203, a second motor; 301 denotes an inverted F gantry; 302 a U-shaped vehicle body; 303 denotes a chassis; 304 denotes a lane guide wheel; reference numeral 305 denotes a control cabinet.

Detailed Description

In order to make the purpose and technical solutions of the embodiments of the present application clearer, the technical solutions of the embodiments of the present application will be clearly and completely described below with reference to the drawings of the embodiments of the present application. It should be apparent that the described embodiments are only some of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the described embodiments of the application without any inventive step, are within the scope of protection of the application.

It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the prior art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

The meaning of "and/or" as used herein is intended to include both the individual components or both.

The meaning of "inside and outside" in this application means that the direction from the outer walls of the left and right carriages to the center of the inverted F-shaped portal is inside, and vice versa, relative to the U-shaped vehicle body itself; and not as a specific limitation on the mechanism of the device of the present application.

The terms "left and right" as used herein refer to the user's left side as the left side and the user's right side as the forward extending direction of the inverted F shaped door frame, rather than the specific limitations on the mechanism of the apparatus of the present application.

The term "connected" as used herein may mean either a direct connection between components or an indirect connection between components via other components.

The meaning of "up and down" in this application means that when the user faces the main body of the U-shaped vehicle, the direction from the roadway to the top end of the inverted F-shaped portal is up, and vice versa is down, and the device mechanism of the present application is not particularly limited.

FIG. 1 is a narrow roadway omnidirectional AGV fork truck according to the application, which includes:

the left side and the right side of the U-shaped vehicle body 302 are provided with carriages, a portal forward moving channel is formed between the carriages, the U-shaped vehicle body 302 can be lengthened in the X direction, and a roadway guide wheel 304 can be further arranged outside a chassis 303;

the inverted F-shaped portal 301 is embedded between the carriages on the left side and the right side, is arranged on the chassis, moves forwards or backwards relative to the U-shaped vehicle body 302 along a portal advancing channel, and drives the fork teeth on the front side to fork and take or put down a cargo tray;

still respectively set up a set of power pack in the left and right sides on the portal 301 of falling F type, every power pack of group includes respectively: a rack and pinion connected between the carriage and the inverted-F gantry 301, and a motor mounted on the back side of the inverted-F gantry 301 for driving the gear; each power unit is respectively connected with the control unit, and correspondingly drives the inverted F-shaped gantry 301 to move along the rack through the motor drive gear in response to a control signal of the control unit so as to drive the fork teeth in front of the gantry to extend forwards or retreat along the gantry advancing channel;

the control unit is also connected with a sensor group and an upper controller, and responds to a sensing signal of the sensor group and an interaction signal of the upper controller to correspondingly adjust a control signal output by the control unit;

the upper controller is used for adjusting the position of the U-shaped body main body 302 along a roadway according to the images of the fork holes of the cargo trays, keeping the U-shaped body main body 302 static after the fork teeth are aligned with the fork holes of the cargo trays, and triggering the control unit to drive the inverted-F-shaped gantry 301 to fork or put down the cargo trays;

the control unit and the upper controller can be installed in the carriage cabinet bodies on the left side and the right side of the U-shaped vehicle body together with the control cabinet of the inverted F-shaped forward-moving type portal frame assembly to form a circuit structure shown in figure 4, and the control unit and the upper controller are electrically connected with the motor on the portal frame through the drag chain to control the portal frame.

From this, two sets of rack and pinion of narrow lane qxcomm technology AGV fork truck accessible portal left and right sides's two servo motor drive respectively of this application, through the two guide rail structure of both sides about the rack, restriction and support the portal about both sides move along portal antedisplacement passageway in step, through the synchronous drive mode realization portal of controlling two servo motor the front and back translation. According to the AGV forklift truck, the electric control parts and mechanical devices required by the forklift truck are transferred from the rear side body to the carriages arranged on the left side and the right side of the body, so that the width of the body of the AGV forklift truck in the front-back direction along the Z axis direction can be greatly reduced, the width of a roadway is reduced, the effective storage space is improved, and the storage density is increased; simultaneously, because this application sets up the rack and pinion at the carriage lateral wall, its stroke distance accessible carriage structure's support and set up and reach 1300 mm. Consequently, the fork truck of this application is getting and is put goods in-process, and U type automobile body main part need not participate in the removal after aiming at fork and getting tray position, and only need drive portal back-and-forth movement, can realize that the goods is got and is put, has shortened greatly and has got and put the goods time, has improved the operating efficiency.

Set up in the two motors of portal left and right sides simultaneously in this application, its supporting servo driver all adopts the Ethercat bus to communicate with PLC the control unit, among the Ethercat bus, communication delay between two drivers can be controlled within 1ms, therefore can realize accurate position synchro control between two motors, and control effect is quick accurate, has solved the problem that the fork was got speed slowly, the operation is unstable, control accuracy is poor under traditional cylinder drive mode.

Detect the sensor group that photoelectricity, prong position detecting element, goods detecting element constitute before the fork in this application to and fork hole recognition cell realizes getting the accurate regulation and control of putting the goods process: the front fork detection photoelectricity is arranged at the front end of the fork tooth, the front fork detection photoelectricity is used for detecting an obstacle in front of the fork tooth, and the control unit is correspondingly triggered to control the fork tooth to stop suddenly according to an obstacle detection signal; the fork tooth position detection unit is arranged on the surface of the side wall of the carriage and between the carriages on the left side and the right side, and is used for detecting and triggering the control unit to control and calibrate the coordinate position of the fork tooth; the goods detection unit is arranged on the front side of the inverted F-shaped portal 301 and the rear side of the fork teeth, and the control unit is triggered to control the inverted F-shaped portal 301 to drive the fork teeth to retreat by utilizing the goods detection unit to respond to the goods forking position; the upper controller is connected with the fork hole identification unit, the fork hole identification unit is arranged on the front side of the inverted F-shaped portal 301 and the rear side of the fork teeth, the upper controller is triggered to drive the U-shaped body main body 302 to correct the angle and the position of the body according to the corresponding pallet fork hole images by utilizing the identification of the pallet fork hole images, and the action of the forklift is accurately regulated and controlled in real time. This application can detect through detect photoelectricity before the fork and whether the fork point hits tray or other barriers, through the fork hole of 3D camera discernment tray among the fork hole recognition unit, combines automobile body angle and position correction again, and the prong hits the tray leg and leads to the safety problem just to being parallel when making the portal frame fork get with the tray fork hole, avoids the fork to get.

Referring to fig. 1 in detail, the inverted F-shaped portal 301 in the narrow roadway omnidirectional AGV forklift of the present invention is assembled into the inverted F-shaped forward moving portal assembly shown in fig. 2 and 3 through an upper set of guide rails and a lower set of guide rails and corresponding sensing and driving devices, and the assembly includes a portal main body, a forward moving guide mechanism, a forward moving driving mechanism, and a detection device:

the gantry main body is an inverted F-shaped gantry 301 integral structure, as shown in fig. 1;

the forward movement guide mechanism comprises an upper guide rail mechanism and a lower guide rail mechanism, wherein an upper group of guide rails and a lower group of guide rails are fixed on the inner side wall of the carriage respectively in a welding mode, the left side and the right side of the portal are connected through a sliding block or rolling shaft structure, and the upper side and the lower side of the carriage on the left side and the right side are horizontally fixed through the edges of the upper side and the lower side of the carriage on the left side and the right side, so that the upper side and the lower side of the inverted F-shaped portal 301 can be supported by the upper group of guide rails and the lower group of guide rails together and are limited to be only horizontally moved and slid along a portal forward movement channel;

the forward moving driving mechanism comprises a first gear, a first rack meshed with the first gear, a first power unit driving the first gear, a second rack meshed with the second gear, and a second power unit driving the second gear; the first power unit comprises a first motor 202 and a first speed reducer which are in transmission connection; the second power unit comprises a second motor 203 and a second speed reducer which are in transmission connection; the two sets of power units are respectively fixed on respective motor supports in a threaded connection mode, and the motor supports of the two sets of power units are respectively fixed on the back of the gantry in a threaded connection mode;

the detection device comprises a front fork detection photoelectric part consisting of a left front fork detection photoelectric part 101 and a right front fork detection photoelectric part 102, a fork tooth position detection unit consisting of a left fork tooth origin detection proximity switch 103, a right fork tooth origin detection proximity switch 108, a fork tooth front limit detection proximity switch 104 and a fork tooth rear limit detection proximity switch 105, a cargo detection unit consisting of a cargo return collision plate detection travel switch 106 and a fork hole identification unit consisting of a 3D pallet fork hole identification camera 107.

In the detection device, the detection photoelectricity in front of the fork is diffuse reflection photoelectricity which is respectively arranged at the front ends of the left fork tooth and the right fork tooth and used for detecting whether a pallet leg or other obstacles exist in front of the fork point under the condition that the goods detection unit is not triggered in the forward moving process of the inverted F-shaped gantry 301, so that the obstacles are detected through the photoelectricity of the fork point in the fork extending process of the fork tooth, and the PLC control unit is triggered through the reflection signals of the obstacles in front of the fork tooth to output control signals to enable the driver to suddenly stop the fork tooth.

In the detection device, the fork tooth position detection unit comprises two groups of guide rails arranged between the upper guide rail and the lower guide rail respectively: the fork tooth front limit detection proximity switch 104 is arranged at the front end of the guide track and is used for detecting the position of the inverted-F-shaped gantry 301 and limiting the front limit of the operation stroke of the fork tooth, and the fork tooth front limit detection proximity switch 104 outputs a sensing signal to the control unit when being triggered by the inverted-F-shaped gantry 301, so that the control unit correspondingly adjusts the control signal output by the control unit to enable the fork tooth to retreat or keep at the current coordinate position; the fork tooth rear limit detection proximity switch 105 is arranged at the rear end of the guide track and is used for detecting the position of the inverted-F-shaped gantry 301 and limiting the rear limit of the operation stroke of the fork tooth, and the fork tooth rear limit detection proximity switch 105 outputs a sensing signal to the control unit when being triggered by the inverted-F-shaped gantry 301, so that the control unit correspondingly adjusts the control signal output by the control unit to enable the fork tooth to advance or be kept at the current coordinate position; a fork tooth origin detection proximity switch, which is arranged between the fork tooth front limit detection proximity switch 104 and the fork tooth rear limit detection proximity switch 105 and is close to the fork tooth rear limit detection proximity switch 105, the fork tooth origin detection proximity switches are respectively arranged on the left and right carriages corresponding to the left and right fork teeth, and are used for detecting the position of the inverted F-shaped gantry 301 through the trigger signals of the switches during electrification and finding the origins of the left and right fork teeth, so that the control unit correspondingly takes the trigger positions of the fork tooth origin detection proximity switches as the coordinate origin positions of the output control signals of the control unit, as long as the two fork tooth origin detection proximity switches at the left and right sides are symmetrically arranged and the distances from the two fork tooth origin detection proximity switches to the front ends of the carriages are adjusted, the fork extending lengths of the two fork teeth at the origin positions can be ensured to be consistent;

in the detection device, the goods detection unit comprises a striking plate detection travel switch which is arranged at the front side of the inverted F-shaped gantry 301 and is positioned at the rear side of the fork teeth, and the striking plate detection travel switch is used for responding to a goods forking position, is triggered by the contact of goods and/or a goods tray when the gantry extends to the right position when a tray is fetched, and outputs a sensing signal to the control unit, so that the control unit correspondingly adjusts the control signal output by the control unit to control the inverted F-shaped gantry 301 to stop forking and then drives the fork teeth to retreat and withdraw;

in the detection device, the fork hole identification unit is mainly realized by a 3D tray fork hole identification camera and a corresponding algorithm identification module and is used for identifying the outline of the fork hole of the III-shaped tray before taking goods, so that the situation that fork teeth and the tray fork hole have deviation when the fork is taken, and the goods taking fails or the tray is collided askew is prevented.

In a specific embodiment, the 3D camera may be a PMD camera, and may calculate, by using a time of flight (TOF) principle, a time from when light is emitted from a camera light source to when the light hits a sensor and is reflected back to a camera receiver, and obtain three-dimensional coordinates (X, Y, Z) of each pixel point of a cargo pallet fork hole image with respect to a camera center point, thereby calculating a distance from a target object to the camera, where X is horizontal coordinate data of the pallet with respect to the camera center point, Y is vertical coordinate data with respect to the camera center point, and Z is radial depth coordinate data with respect to the camera center point.

The light source of the PMD camera can adopt an infrared light source, the light source scans each pixel point of the camera by taking the center of the camera as an imaging coordinate origin, three-dimensional coordinates from the light source to the corresponding position of the pixel point are respectively calculated, image data are output, and each frame of image comprises data such as an amplitude image, a distance image and coordinates (X, Y, Z) of each pixel point on the image relative to the center.

The identification module firstly screens and compares data through setting an amplitude threshold value, extracts a tray fork hole surface profile and a corresponding distance image which are closest to the tray fork hole surface profile according to a preset pixel point amplitude value, and can also record the threshold value data as experience data for later screening; then, extracting contour edge feature points from the distance image to obtain a tray contour image of a fork hole surface and distance data of image edge pixel points, assuming that coordinates of pixel points at the left edge of the tray are (X1, Y1 and Z1) and coordinates of pixel points at the right edge of the tray are (X2, Y2 and Z2), calculating a tray picture width delta X1= abs (X1) + abs (X2) according to the transverse width of the tray fork hole surface contour and diameter depth data in the distance image, comparing the difference between the tray picture width delta X1 and the actual tray width L1, judging tray inclination when the difference exceeds a set standard, calculating an inclination offset and correspondingly triggering a host controller to drive a U-shaped vehicle body 302 to correspondingly correct the angle and the position of the vehicle body according to the inclination offset; when the difference value does not exceed the set standard, for example, when Δ X1= L1 ± 5mm, the U-shaped car body 302 is kept still by the upper controller, and the trigger control unit drives the inverted F-shaped gantry 301 to fork or put down a cargo pallet. The identification module can be further configured to calculate the inclination angle theta = arctan ((Z1-Z2)/[ delta ] X1) of the tray through the three-dimensional coordinates of the pixel points when the tray is considered to be inclined, and the tray or the offset of the fork holes can be obtained by comparing the acquired X data of the pixel points at the edges of the fork holes with the distance from the original actual edges of the fork holes to the central point. Detailed description and computational model reference is made to figure 5.

Therefore, the narrow roadway omnidirectional AGV forklift with the inverted-F forward type door frame assembly can be used as shown in FIG. 6, and after the narrow roadway omnidirectional AGV forklift is powered on, the narrow roadway omnidirectional AGV forklift is firstly detected according to the sensing signals of the fork tooth position detection unit and triggers the control unit to calibrate the coordinate positions of the fork teeth; then according to the interactive signal of the upper controller, after the fork teeth are aligned with the fork holes of the goods tray, the U-shaped vehicle body 302 is kept static, and the control unit is triggered to drive the inverted-F-shaped door frame 301 to move so as to realize the fork taking or putting down of the goods tray.

In the taking and placing process, the forklift can be further provided with a control unit connected with the inverted-F type gantry 301, and the control unit is correspondingly triggered to control the fork teeth and the inverted-F type gantry 301 to suddenly stop according to reflection signals of obstacles in front of the fork teeth, which are obtained by photoelectric detection in front of the fork, under the condition that the goods detection unit is not triggered in the advancing process;

and correspondingly switches the control signal output by the control unit to control the inverted-F-shaped gantry 301 to drive the fork teeth to retreat and retract after the cargo detection unit is detected to be triggered.

In the specific operation process, the AGV fork truck of this application installs switch board 305 in automobile body left side carriage, sets up the control unit into the PLC who takes Ethercat bus motion control, and concrete optional confluent AM401 system PLC, set up the servo driver of controlling two motors into the driver that takes Ethercat bus control, and concrete optional shanghai is with automatic IXL-II series driver with the resolute, and the control system block diagram can refer to the setting shown in FIG. 4 between each device:

the PLC comprises two network ports, wherein a net1 port, namely an Ethernet port, is connected with the upper controller through a network cable and is communicated with the upper controller through Modbustcp to receive fork extending and retracting action instructions of the upper controller and return all state information of the fork teeth to the upper controller.

The other net port net2 port of the PLC, namely the Ethercat port, is connected with the Ethercat port of the driver connected with the fork tooth driving motor through the net wire, the first driver and the second driver are connected in a daisy chain mode through the net wire, an additional switch is omitted, and the PLC can send synchronous control instructions to the two drivers through the Ethercat bus. The PLC is used as an Ethercat master station, the two drivers are used as Ethercat slave stations, the master station PLC sends synchronous position control instructions to the two drivers through an Ethercat bus, and after the drivers receive the master station instructions, the drivers further control the two motors to synchronously rotate forwards, reversely, stop and accelerate and decelerate according to the position, speed and other instructions sent by the master station to realize the extension and retraction of the portal frame so that the portal frame runs to a target position.

In the goods taking process, the upper controller drives the traveling wheel under the chassis to drive the whole vehicle body to travel to the position of the tray, then the 3D camera identifies whether the position of the fork hole has deviation or inclination, if so, the upper controller translates or rotates through a double-steering-wheel driving structure of the chassis to align, and after the alignment, the double-fork-tooth forward-extending synchronous motion is started; if the tray collision plate is touched to detect the travel switch in the operation process, the fork tooth fork is taken in place, and the withdrawing fork tooth can move to the withdrawing target position in the next step; if the detection travel switch of the tray collision plate is not triggered in the forward extension movement process and the front limit proximity switch or the fork front detection photoelectric switch is triggered, abnormal alarm is given and the fork extension action is stopped.

The specific control flow is as follows, and reference can be made to the control system flow chart shown in fig. 6:

firstly, after the whole control system is powered on, a self-checking flow is started. The master station PLC firstly detects the online state, the ready state and other states of the two slave station drivers through the Ethercat bus, and the master station PLC enters the next step if no abnormality exists.

The PLC control unit is provided with a first power shaft and a second power shaft which respectively correspond to the running states of the left side and the right side of the portal frame, and a virtual shaft; the PLC judges whether the fork teeth of the gantry are in the original point position or not through the original point connected by the IO and the states of the front limit proximity switch and the rear limit proximity switch, and if the fork teeth are not in the original point position, the fork teeth return to the original point flow is started to calibrate the coordinates of each axis.

In the process of returning the fork teeth to the original point, the inverted-F gantry 301 moves to the trigger position of the fork tooth front limit detection proximity switch 104 or the fork tooth rear limit detection proximity switch 105 along a single direction, then the inverted-F gantry 301 is driven to move to the trigger position of the fork tooth original point detection proximity switch along the gantry forward moving channel in the opposite direction, and the first power shaft and the second power shaft are arranged to be calibrated to the original point position respectively by using the trigger position. For example, the PLC may operate in a first-to-last limiting direction, and if the rising edge of the origin proximity switch signal is found in this process, the position at this time is set as the origin position of the tine, and the positions of the two drivers are set to 0, and then the tine returns to the origin; if the rising edge of the limit switch signal is found first and then runs reversely, and the falling edge of the origin switch signal is found during the reverse running, the position at the moment is set as the origin position of the fork teeth, the positions of the two drivers are set as 0, and the return of the fork teeth to the origin is finished; if the falling edge signal of the proximity switch cannot be found in the process and the front limit signal is received, the fork tooth fails to return to the original point. The processes of finding the original points by the two fork teeth are the same and can be performed simultaneously without mutual interference, after the processes of finding the original points by the two fork teeth are completely completed, the processes of finding the original points by the fork teeth are calculated to be completed, or one process fails to complete the other process, and the processes of finding the original points are restarted after maintenance is needed.

Then, the PLC can feed back the completion status of the return to the origin to the upper controller through the MODBTCP protocol. If the return to the original point is completed, the self-checking is completed and the next step is carried out, and if the return to the original point fails, an alarm is given and fault information is displayed.

After the self-checking is completed, the upper controller can correspondingly control the fork teeth to extend out according to the angle position of the automobile body, and in the process, the upper controller can be specifically executed according to the following modes: the fork tooth extending message is sent to the PLC through a ModbusTCP protocol, after the message is received by the PLC, the information such as the position of the fork tooth extending out of a target point, the running speed and the acceleration and deceleration of the fork tooth is respectively sent to the two drivers through an Ethercat bus in an RPDO mode, the two drivers run to the target position according to the received instruction information and feed back the target position to the completion state of the master station PLC, and after the completion state is received by the PLC, the completion state of the fork extending action is fed back to the upper controller through an MODBUSTCP instruction message. The entire control of the fork motion is completed. The action flow of the fork retraction is the same as that of the fork extension, and only the target position is the original position.

Considering that the two motors on the left and right sides of the inverted F-shaped gantry 301 need to be synchronously driven to ensure that the gantry can stably move, the process of controlling the forward and backward movement of the gantry can be realized by the control of the motion shaft inside the PLC: two power shafts and a virtual shaft are configured inside the PLC, the first power shaft and the second power shaft are respectively bound with the virtual shaft, and the electronic gear ratio is set to be 1 during binding: 1; when the inverted F-shaped gantry 301 returns to the origin of the fork teeth to detect the trigger position of the proximity switch, a first power shaft and a second power shaft are arranged and are respectively calibrated by taking the trigger position as the origin position; when the motor is controlled to run, the motor tail encoder adopts an absolute value encoder, corresponding control instructions such as position, speed, acceleration and deceleration are sent to the virtual shaft according to sensing signals of the sensor group and interaction signals of the upper controller, the fork tooth extending out of the target position is set to be a position represented by a target encoder value relative to an original point, a PLC internal program automatically sends corresponding speed instructions to the two drivers respectively, real-time speed and real-time position of the two motors are collected in real time, the internal program automatically coordinates the first power shaft and the second power shaft to drive the motor on the side according to an electronic gear ratio of 1:1 respectively, and position synchronous control of the two shafts is completed according to the control instructions of the virtual shaft. In the process of withdrawing the fork tine, the target position can be correspondingly set to be another position of a target encoder value relative to the origin, the withdrawing fork tine under the condition that no goods to be loaded and unloaded are on the fork tine sets the withdrawing target value to be that the fork tine is withdrawn to the origin position, and when goods/pallets are loaded on the fork tine, the fork tine is considered to be withdrawn to the position when the stroke switch is detected by detecting the pallet striking plate.

The front limit position and the rear limit position calibrated by the fork tooth front limit detection proximity switch 104 or the fork tooth rear limit detection proximity switch 105 are the foremost and rearmost limit points of the fork tooth stroke, and the fork tooth or the gantry generally causes the forklift to alarm after the fork tooth or the gantry runs to the switch position to trigger the limit detection proximity switch; in the process of searching the origin, after the fork teeth are operated to the position, the fork teeth are operated correspondingly in the reverse direction to search the origin of the fork teeth and detect the trigger position of the proximity switch, so that the origin calibration is realized. In the normal fork tooth fork extending and retracting process, the two limit detection proximity switches at the front limit position and the rear limit position cannot be triggered.

When the dual-shaft drive has deviation, the two motors can realize synchronization by setting the maximum position deviation of the two shafts and the virtual shaft bound in the software of the control unit, such as 50 pulses: when the power shaft is in operation, the speed and the position of the two power shafts can be output in real time along with the virtual shaft respectively, and according to the position deviation of the power shaft and the virtual shaft, the speed is slightly adjusted to be high or low so as to eliminate the following position error of the power shaft and the virtual shaft, and further, the synchronization of the two power shafts and the virtual shaft, namely the synchronization of the two power shafts is achieved.

In conclusion, the application provides a forklift control method based on Ethercat bus control and an omnidirectional AGV forklift scheme suitable for a narrow roadway, the front and back movement of a gantry is achieved through a double-shaft synchronous motion control mode, accurate forking and goods placing are carried out on a tray in an inverted-F type forward-moving type gantry assembly front and back movement mode, the Y-direction vehicle body width is greatly shortened, the roadway width is reduced, meanwhile, the stroke of a rack-and-pinion driving the forward-moving type gantry assembly front and back movement can reach 1300mm, the vehicle body does not need to participate in movement in the goods taking and placing process of the forklift, only the gantry front and back movement is needed, compared with a traditional AGV, the goods taking and placing time is shortened, and the operation efficiency is improved.

This application adopts two servo drive power pack, is different from the single power oil pump control of traditional fork truck portal, and two servo drives adopt Ethercat high speed bus to carry out the communication, have realized the real-time position synchronization of biax. The forklift is rapid and stable in starting and stopping, quick in response, the communication time between all stations between buses is once in the minimum 1ms, the bus communication speed is 100Mbps, accurate position synchronous control between two motors can be realized, the control effect is rapid and accurate, and the problems that the crude oil cylinder driving fork taking speed is slow, the operation is not stable, and the control precision is poor are solved.

The utility model provides a detection device has adopted 3D tray fork hole discernment camera among fork truck, through the fork hole of 3D camera discernment tray, it is just to being parallel with tray fork hole when combining automobile body angle and position correction again, make the portal frame fork get, the prong hits the tray leg when avoiding the fork to get and leads to the safety problem, do not detect and the position appearance adjustment and the mode that the tray was got to the fork tooth fork that directly moves forward after comparing in traditional fork truck AGV chassis location, the security when having improved the fork and getting the tray.

The above are merely embodiments of the present application, and the description is specific and detailed, but not construed as limiting the scope of the present application. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the concept of the present application, which falls within the protection scope of the present application.

Claims

1. A control method of a narrow roadway omnidirectional AGV forklift is characterized in that the narrow roadway omnidirectional AGV forklift is provided with a fork tooth position detection unit, a goods detection unit and a fork front detection photoelectricity, and the control method comprises the following steps:

after the power is on, detecting and triggering a control unit to calibrate the coordinate position of the fork tooth according to the sensing signal of the fork tooth position detection unit;

according to an interaction signal of the upper controller, after the fork teeth are aligned with fork holes of the goods tray, the U-shaped vehicle body main body (302) is kept static, and the control unit is triggered to drive the inverted-F-shaped gantry (301) to move to realize forking or putting down of the goods tray;

in the forward movement process of the inverted F-shaped gantry (301), under the condition that the goods detection unit is not triggered, the control unit is correspondingly triggered to control the fork teeth and the inverted F-shaped gantry (301) to suddenly stop according to reflection signals of obstacles in front of the fork teeth, which are obtained by photoelectric detection in front of the fork;

after the goods detection unit is triggered, the control unit controls the inverted F-shaped gantry (301) to drive the fork teeth to retreat and retract.

2. The narrow roadway omnidirectional AGV fork truck control method according to claim 1, wherein said control unit is provided with a first power shaft and a second power shaft corresponding to the left and right operating states of the inverted F-shaped gantry, respectively, and further provided with a virtual shaft;

the specific steps of the control unit detecting and triggering the control unit to calibrate the coordinate position of the fork according to the sensing signal of the fork position detection unit include:

firstly, driving an inverted F-shaped gantry (301) to move to a trigger position of a fork tooth front limit detection proximity switch (104) or a fork tooth rear limit detection proximity switch (105) along a single direction, then driving the inverted F-shaped gantry (301) to move to the trigger position of a fork tooth origin detection proximity switch along a gantry forward moving channel in the opposite direction, and setting a first power shaft and a second power shaft to calibrate the trigger position of the fork tooth origin detection proximity switch as an origin position respectively;

the tine position detection unit is further configured to: after detecting the sensing signal of the inverted F-shaped gantry (301) moving to the triggering position of the fork tooth front limit detection proximity switch (104) or the triggering position of the fork tooth rear limit detection proximity switch (105), the triggering control unit controls the fork tooth and the inverted F-shaped gantry (301) to keep at the current coordinate position or move in the opposite direction.

3. The narrow roadway omnidirectional AGV forklift control method according to claim 2, wherein the specific step of the control unit driving the inverted F-shaped gantry (301) to move includes:

firstly, controlling an inverted F-shaped gantry (301) to return to a trigger position of a prong origin detection proximity switch, and setting a first power shaft and a second power shaft to calibrate the trigger position of the prong origin detection proximity switch as an origin position respectively;

then, sending corresponding position, speed, acceleration or deceleration control instructions to the virtual shaft according to the sensing signals of the sensor group and the interaction signals of the upper controller;

and controlling the first power shaft and the second power shaft to drive the power units on the left side and the right side of the inverted F-shaped gantry according to the control instruction of the virtual shaft and the electronic gear ratio of 1:1 respectively, so that the inverted F-shaped gantry (301) moves along the gantry forward moving channel.

4. The utility model provides a narrow tunnel qxcomm technology AGV fork truck which characterized in that includes:

the left side and the right side of the U-shaped body main body (302) are provided with carriages, and a gantry advance channel is formed between the carriages;

the inverted F-shaped portal (301) is arranged between the carriages at the left side and the right side, moves forwards or backwards relative to the U-shaped vehicle body main body (302) along a portal advancing channel, and drives fork teeth at the front side of the inverted F-shaped portal (301) to fork or put down a cargo tray;

the left side and the right side of the inverted F-shaped gantry (301) are respectively provided with a group of power units, the power units are connected with the control unit, and the inverted F-shaped gantry (301) is correspondingly driven to drive the fork teeth to move along the gantry advancing channel in response to a control signal of the control unit;

the upper controller is used for adjusting the position of the U-shaped vehicle body main body (302) along a roadway according to the images of the fork holes of the cargo tray, keeping the U-shaped vehicle body main body (302) static after the fork teeth are aligned with the fork holes of the cargo tray, and triggering the control unit to drive the inverted-F-shaped gantry (301) to fork and take or put down the cargo tray;

the sensor group comprises at least: and the fork tooth position detection unit is arranged on the surface of the side wall of the carriage and positioned between the carriages on the left side and the right side and is used for detecting and triggering the control unit to calibrate the coordinate position of the fork tooth.

5. The narrow lane, omnidirectional AGV forklift of claim 4, wherein the sensor set further comprises:

the front fork detection photoelectric sensor is arranged at the front end of the fork teeth and used for detecting obstacles in front of the fork teeth and correspondingly triggering the control unit to control the fork teeth to stop suddenly according to obstacle detection signals;

the goods detection unit is arranged on the front side of the inverted F-shaped gantry (301), is positioned on the rear side of the fork teeth, and is used for triggering the control unit to control the inverted F-shaped gantry (301) to drive the fork teeth to retreat in response to the goods forking position;

the upper controller is connected with a fork hole identification unit, the fork hole identification unit is arranged on the front side of the inverted-F-shaped gantry (301) and located on the rear side of the fork teeth, and is used for identifying images of the fork holes of the cargo pallet to trigger the upper controller to drive the U-shaped vehicle body main body (302) to correspondingly correct the angle and the position of the vehicle body according to the pallet fork holes.

6. The narrow roadway omnidirectional AGV forklift of claim 5, wherein two sets of guide rails are horizontally provided between the left and right carriages at the upper and lower side edges of the carriages, respectively, and the upper and lower sides of the inverted F-shaped gantry (301) are supported by the guide rails together and are restricted to sliding only in a forward and backward translational manner along the gantry forward path;

the fork tooth position detection unit comprises two groups of guide rails arranged between the upper guide rail and the lower guide rail respectively:

the fork tooth front limit detection proximity switch (104) is arranged at the front end of the guide track and used for detecting the position of the inverted-F-shaped gantry (301), and the fork tooth front limit detection proximity switch (104) outputs a sensing signal to the control unit when being triggered by the inverted-F-shaped gantry (301), so that the control unit correspondingly adjusts the control signal to enable the fork tooth to retreat or keep at the current coordinate position;

the fork tooth rear limit detection proximity switch (105) is arranged at the rear end of the guide track and used for detecting the position of the inverted-F-shaped gantry (301), and the fork tooth rear limit detection proximity switch (105) outputs a sensing signal to the control unit when being triggered by the inverted-F-shaped gantry (301), so that the control unit correspondingly adjusts the control signal to enable the fork tooth to advance or keep at the current coordinate position;

and the prong origin detection proximity switch is arranged between the prong front limit detection proximity switch (104) and the prong rear limit detection proximity switch (105) and is positioned at the position close to the prong rear limit detection proximity switch (105), and the prong origin detection proximity switch is used for detecting the position of the inverted F-shaped gantry (301), so that the control unit correspondingly takes the trigger position of the prong origin detection proximity switch as the coordinate origin position of the control signal output by the control unit.

7. The narrow roadway omnidirectional AGV fork truck of claim 6, wherein the control unit is provided with a first power shaft and a second power shaft corresponding to the running states of the left side and the right side of the inverted F-shaped gantry respectively, and further provided with a virtual shaft, and the control unit controls and drives the inverted F-shaped gantry (301) to move according to the following steps in the process of forking or putting down the cargo tray each time:

the first power shaft and the second power shaft respectively drive the power units on the left side and the right side of the inverted F-shaped gantry according to the control instruction of the virtual shaft according to the electronic gear ratio of 1:1, so that the inverted F-shaped gantry (301) moves along the gantry advancing channel.

8. The narrow roadway omnidirectional AGV forklift of claim 6, wherein the fork front detection photoelectricity is respectively arranged at the front ends of the left fork tooth and the right fork tooth, and is used for responding to a reflection signal of an obstacle in front of the fork teeth under the condition that the goods detection unit is not triggered in the forward moving process of the inverted F type gantry (301), and correspondingly triggering the control unit to control the fork teeth and the inverted F type gantry (301) to suddenly stop.

9. The narrow roadway omnidirectional AGV forklift of claim 6, wherein the cargo detection unit is arranged at the front side of the inverted F-shaped gantry (301) and at the rear side of the fork teeth, and is used for responding to the cargo forking position and outputting a sensing signal to the control unit when being triggered by the contact of the cargo and/or the cargo tray, so that the control unit controls the inverted F-shaped gantry (301) to drive the fork teeth to retreat and retract.

10. A narrow lane, omnidirectional AGV according to claim 5 wherein said fork aperture identification unit includes:

the 3D camera is used for acquiring three-dimensional coordinates (X, Y and Z) of each pixel point of the goods pallet fork hole image relative to the center point of the camera;

an identification module configured to:

firstly, extracting the outline of the tray fork hole surface and a corresponding distance image according to a preset pixel point amplitude value;

calculating a tray picture width delta X1 according to the transverse width of the outline of the tray fork hole and the radial depth data in the distance image, comparing the difference value between the tray picture width delta X1 and the actual tray width L1, judging the tray inclination when the difference value exceeds a set standard, calculating the inclination offset, and correspondingly triggering an upper controller to drive the U-shaped vehicle body main body (302) to correspondingly correct the vehicle body angle and position according to the inclination offset; when the difference value does not exceed the set standard, the U-shaped vehicle body (302) is kept static through the upper controller, and the trigger control unit drives the inverted F-shaped gantry (301) to fork and take or put down the goods tray.