High-position goods picking and placing method of forward-moving type unmanned forklift

Abstract

The invention relates to the technical field of intelligent storage and unmanned forklifts, in particular to a high-position goods picking and placing method for a forward-moving type unmanned forklift, which comprises an industrial personal computer, and a software system of the industrial personal computer adopts a modular structure and mainly comprises a chassis control module, a fork arm control module, a visual detection module, a task management module and a safety protection module. And a peripheral module and a web module. The forward-moving type unmanned forklift is large in chassis, stable in forklift body, small in shaking when the fork arm is lifted, high enough in lifting height, capable of easily achieving the lifting height of 10 m or above, small in forklift body length when the portal frame is retracted, suitable for narrow roadways, safe and reliable, capable of improving the goods taking and placing precision and the goods stability in the operation process, and capable of being used for a large-scale industrial production line. An image recognition technology based on deep learning is adopted to detect the position of goods or a goods shelf relative to a forklift, and the goods are accurately taken and placed by adjusting the transverse movement amount of a fork arm and planning a warehousing route.

Description

Technical Field

[0001] The present invention relates to the technical field of smart warehousing and unmanned forklifts, and specifically to a high-position cargo picking and placing method using a forward-moving unmanned forklift. Background Art

[0002] A forklift is an industrial handling vehicle, which refers to various wheeled handling vehicles that are used for loading and unloading, stacking and short-distance transportation of palletized goods. They are often used to transport large objects in warehouses and are usually powered by a fuel engine or battery.

[0003] However, when the existing forklift is performing the picking and placing operation, it is necessary to manually drive the forklift to operate. In special cases, an observer is also required to observe the picking and placing operation in real time. This purely relies on naked eye observation, which is less safe and increases labor intensity. Summary of the invention

[0004] The object of the present invention is to provide a high-position cargo picking and placing method for a forward-moving unmanned forklift to solve the problem of low safety of naked-eye observation when picking and placing cargo in the above-mentioned background technology.

[0005] To achieve the above object, the present invention provides the following technical solution: a high-position cargo picking and placing method of a forward-moving unmanned forklift, comprising:

[0006] The industrial computer has a software system with a modular structure, which mainly includes a chassis control module, a fork arm control module, a visual inspection module, a task management module, a safety protection module, a peripheral module and a web module.

[0007] Preferably, the chassis control module is responsible for chassis control of the reach-type unmanned forklift, and the fork arm control module is responsible for fork arm control of the reach-type unmanned forklift.

[0008] Preferably, the visual inspection module is responsible for the identification and position detection of pallets and shelves.

[0009] Preferably, the task control module is responsible for communicating with the scheduling system, splitting tasks, and coordinating work with other modules in series.

[0010] Preferably, the safety protection module calculates the distance of obstacles around the reachable unmanned forklift in real time.

[0011] Preferably, S1. When picking up goods, the reach-type unmanned forklift goes to the entry point corresponding to the target warehouse location according to the route planned by the dispatching system, the fork arm is raised to the fork entry height and the pitch angle is adjusted to the horizontal, and the posture recognition of the pallet to be picked up is performed using a rear-view stereo camera. If the lateral offset value of the pallet to be picked up relative to the reach-type unmanned forklift is less than the maximum lateral travel of the fork arm, the fork arm is moved horizontally so that the fork tip is aligned with the fork entry hole; otherwise, the fork arm is moved horizontally to the maximum travel, and a local path planning is performed on the entry route so that the fork tine is located in the middle of the fork entry hole after entry. If the entry line is not re-planned, the fork is entered into the warehouse along the predetermined entry route; otherwise, the fork is entered into the warehouse along the re-planned route;

[0012] S2. Arrive at the storage point, lift the fork arm to the outbound height, and tilt the fork arm up to the maximum elevation angle to ensure that the goods are stable when outbound. Go outbound in the reverse direction of the route when entering the warehouse. Arrive at the outbound point, lower the fork arm to a safe height for walking, move horizontally to zero position, maintain the elevation angle, and complete the picking up of goods, and go to the delivery point.

[0013] Preferably, S1. When releasing the goods, the forward-moving unmanned forklift goes to the entry point corresponding to the target storage location according to the route planned by the dispatching system, the fork arm is raised to the entry height and the pitch angle is adjusted to the maximum elevation angle to ensure the stability of the goods when entering the warehouse, and the rear-view stereo camera is used to perform posture recognition on the shelf to detect the relative error between the target placement position and the current position of the forklift. If the relative lateral error detected before is less than the maximum lateral stroke of the fork arm, the fork arm is moved horizontally to align the goods with the position to be placed; otherwise, the fork arm is moved horizontally to the maximum stroke, and the local path planning is performed on the entry route so that the goods are exactly located at the position to be released after entering the warehouse. If the entry line is not re-planned, the goods are entered into the warehouse along the original entry line; otherwise, the goods are entered into the warehouse along the re-planned route;

[0014] S2. Upon arrival at the storage point, the fork arm pitch angle is adjusted to a horizontal state; the fork arm is lowered so that the goods fall on the shelf and are shipped out in the reverse direction of the entry route. Upon arrival at the shipping point, the fork arm is lowered to a safe height for walking and moved horizontally to zero position. The goods are released and the dispatching instructions are awaited.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] (1) The forward-moving unmanned forklift of the invention has a large chassis, a stable body, and little shaking when the fork arm is raised. The lifting height is high enough and can easily reach a lifting height of more than 10 meters. When the gantry is retracted, the body length is small, which is suitable for narrow alleys, freeing workers and being safe and reliable.

[0017] (2) The forward-moving unmanned forklift of the invention occupies a small area, can operate in a narrow space, and has a high lifting height. The use of the forward-moving unmanned forklift can effectively increase the storage capacity of the warehouse. The forward-moving unmanned forklift can operate completely autonomously, saving labor costs. The unique anti-collision function improves its operating safety factor without increasing the hardware cost. It fully utilizes the pitch and lateral movement functions of the fork arm, rather than the common blind picking and placing with only lifting and lowering and forward and backward movement, which improves the accuracy of picking and placing goods and the stability of goods during operation. It uses image recognition technology based on deep learning to detect the position of goods or shelves relative to the forklift, and accurately picks and places goods by adjusting the lateral movement of the fork arm and planning the warehousing route. The unique safety protection scheme improves the safety factor of the forklift when entering and leaving the warehouse without increasing the hardware cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a structural diagram of the controller software system of the present invention;

[0019] Figure 2 A flow chart of picking up goods from a high shelf according to the present invention;

[0020] Figure 3 A flow chart of placing goods on a high shelf according to the present invention;

[0021] Figure 4 It is a schematic diagram of the anti-collision detection feature points of high-position pickup according to the present invention. DETAILED DESCRIPTION

[0022] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] See also Figure 1-4 , an embodiment provided by the present invention: a high-position cargo picking and placing method of a forward-moving unmanned forklift.

[0024] Including: industrial computer. The software system of the industrial computer adopts a modular structure, mainly including chassis control module, fork arm control module, visual inspection module, task management module, safety protection module, peripheral module and web module.

[0025] Furthermore, the chassis control module is responsible for the chassis control of the forward-moving unmanned forklift. By giving the steering wheel angle and the driving wheel speed, the forward-moving unmanned forklift can run smoothly along the predetermined route. In addition, during the high-level warehousing stage, the module also needs to perform local path planning for the warehousing route. The fork arm control module is responsible for the fork arm control of the forward-moving unmanned forklift. When picking up goods, the fork arm control system needs to control the fork arm to move in the order of forward-lifting-backward-backward, and each sub-action has strict requirements on control accuracy.

[0026] Furthermore, the visual inspection module is responsible for the identification and position detection of pallets and shelves. When the forward-moving unmanned forklift is picking up and placing goods on high-level shelves, it must perform target detection on the shelves or pallets in advance before entering the storage location to ensure that the fork teeth can accurately enter the fork hole of the pallet when picking up goods, and the goods can be accurately placed on the shelf when placing goods, thereby avoiding accidents of colliding with goods or shelves.

[0027] The visual inspection of pallets and shelves uses image recognition technology based on deep learning. During the project deployment phase, it is necessary to collect images of all types of pallets and shelves that may be used, mark the collected images one by one, and generate a sample library. When it is necessary to pick up goods from the high-level shelf and the visual inspection system receives a target detection request, the coordinates of the feature center of the pallet to be picked up in the camera coordinate system are found by triggering the process of taking pictures, image segmentation, and model matching, and then converted to the world coordinate system to complete the target detection. Examples of image recognition are as follows: Figure 4 shown.

[0028] Furthermore, the task control module is responsible for communicating with the scheduling system, splitting tasks, and coordinating work with other modules in series.

[0029] Furthermore, the safety protection module calculates the distance of obstacles around the forward-moving unmanned forklift in real time.

[0030] Reach-type unmanned forklifts are generally equipped with multiple sets of obstacle avoidance radars and safety edge touch components to achieve 360° safety protection without blind spots. However, when the fork arm of the reach-type unmanned forklift is raised to a height of more than ten meters, the fork arm will enter the blind spot of the obstacle avoidance radar. At this time, all protective devices will fail. In order to avoid the fork arm from scratching against the pallet or the goods from scratching against the shelf when entering the warehouse, the present invention proposes an obstacle avoidance strategy that uses the positioning results for safety protection.

[0031] Take pickup as an example. Figure 4 As shown in the figure, the feature point position of the pallet is obtained by visual inspection at the entry point, and the four feature points on the edge of the fork hole can be calculated as follows:

[0032]

[0033] Among them, m and n represent the distance from the outer and inner surfaces of the fork hole to the center axis of the pallet respectively.

[0034] During the forklift entering the warehouse, if the coordinates of the reference point at a certain moment are, then the coordinates of the four corner points on the outside and inside of the fork arm tip at that moment are:

[0035]

[0036] Among them, d, k, and l are the horizontal distance from the fork tip to the reference point, the outer spacing of the fork arms, and the inner spacing of the fork arms, respectively.

[0037] The condition for no scratches is that Q1 and Q2 are between P1 and P2, and Q3 and Q4 are between P3 and P4. If this condition is not met at a certain moment, the vehicle must stop immediately.

[0038] This method does not rely on real-time point cloud images and can effectively improve the safety factor of forward-moving unmanned forklifts entering the high-level shelf to pick up and place goods without installing other obstacle avoidance equipment.

[0039] Further, S1. When picking up goods, the reach-type unmanned forklift goes to the entry point corresponding to the target warehouse location according to the route planned by the dispatching system, the fork arm is raised to the fork entry height and the pitch angle is adjusted to the horizontal, and the posture of the pallet to be picked up is recognized by the rear-view stereo camera. If the lateral offset value of the pallet to be picked up relative to the reach-type unmanned forklift is less than the maximum lateral travel of the fork arm, the fork arm is moved horizontally so that the fork tip is aligned with the fork entry hole; otherwise, the fork arm is moved horizontally to the maximum travel, and the local path planning is performed on the entry route so that the fork tine is located in the middle of the fork entry hole after entry. If the entry line is not re-planned, the fork is entered into the warehouse along the predetermined entry route; otherwise, the fork is entered into the warehouse along the re-planned route;

[0040] S2. Arrive at the storage point, lift the fork arm to the outbound height, and tilt the fork arm up to the maximum elevation angle to ensure that the goods are stable when outbound. Go outbound in the reverse direction of the route when entering the warehouse. Arrive at the outbound point, lower the fork arm to a safe height for walking, move horizontally to zero position, maintain the elevation angle, and complete the picking up of goods, and go to the delivery point.

[0041] Further, S1. When releasing the goods, the forward-moving unmanned forklift goes to the entry point corresponding to the target warehouse location according to the route planned by the dispatching system, the fork arm is raised to the entry height and the pitch angle is adjusted to the maximum elevation angle to ensure the stability of the goods when entering the warehouse, and the rear-view stereo camera is used to perform posture recognition on the shelf to detect the relative error between the target placement position and the current position of the forklift. If the relative lateral error detected before is less than the maximum lateral travel of the fork arm, the fork arm is moved horizontally to align the goods with the position to be placed; otherwise, the fork arm is moved horizontally to the maximum travel, and the local path planning is performed on the entry route so that the goods are exactly at the position to be released after entering the warehouse. If the entry line is not re-planned, the goods are entered into the warehouse along the original entry line; otherwise, the goods are entered into the warehouse along the re-planned route;

[0042] S2. Upon arrival at the storage point, the fork arm pitch angle is adjusted to a horizontal state; the fork arm is lowered so that the goods fall on the shelf and are shipped out in the reverse direction of the entry route. Upon arrival at the shipping point, the fork arm is lowered to a safe height for walking and moved horizontally to zero position. The goods are released and the dispatching instructions are awaited.

[0043] Working principle: When picking up goods, the reach-forklift goes to the entry point corresponding to the target warehouse according to the route planned by the dispatching system. The fork arm is raised to the fork entry height and the pitch angle is adjusted to the horizontal. The rear-view stereo camera is used to recognize the posture of the pallet to be picked up. If the lateral offset value of the pallet to be picked up relative to the reach-forklift is less than the maximum lateral stroke of the fork arm, the fork arm is moved horizontally so that the fork tip is aligned with the fork entry hole; otherwise, the fork arm is moved horizontally to the maximum stroke, and the local path planning is performed on the entry route so that the fork tine is located in the middle of the fork entry hole after entry. If the entry line is not re-planned, the fork is entered along the predetermined entry route; otherwise, the fork is entered along the re-planned route, and when it arrives at the warehouse location, the fork arm is raised to the exit height and the fork arm is tilted up to the maximum elevation angle to ensure that the goods are stable when leaving the warehouse, and the goods are exited in the opposite direction according to the entry route. When it arrives at the exit point, the fork arm is lowered to a safe height for walking, and moves horizontally to zero position, maintaining the elevation angle. The picking is completed and the goods go to the delivery point.

[0044] When releasing the goods, the forward-moving unmanned forklift goes to the entry point corresponding to the target storage location according to the route planned by the scheduling system. The fork arm is raised to the storage height and the pitch angle is adjusted to the maximum elevation angle to ensure the stability of the goods when entering the warehouse. The rear-view stereo camera is used to perform posture recognition on the shelf to detect the relative error between the target storage position and the current position of the forklift. If the relative lateral error detected before is less than the maximum stroke that the fork arm can move horizontally, the fork arm is moved horizontally to align the goods with the position to be placed; otherwise, the fork arm is moved horizontally to the maximum stroke, and the local path planning is performed on the storage route so that the goods are exactly located at the position to be released after entering the warehouse. If the storage line is not re-planned, the original storage line is entered into the warehouse; otherwise, the goods are entered into the warehouse along the re-planned route. When arriving at the storage point, the pitch angle of the fork arm is adjusted to a horizontal state; and the fork arm is lowered so that the goods fall on the shelf and are shipped out in the opposite direction according to the route when entering the warehouse. When arriving at the shipping point, the fork arm is lowered to a safe height for walking and moved horizontally to zero position. The release of goods is completed and the scheduling instructions are awaited. The above is the entire working principle of the present invention.

[0045] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

Claims

1. A method for picking up and placing goods at a high position by a forward-moving unmanned forklift, characterized in that: include: The industrial computer has a software system with a modular structure, which mainly includes a chassis control module, a fork arm control module, a visual inspection module, a task management module, a safety protection module, a peripheral module and a web module.

2. A method for picking up and placing goods at a high position by a forward-reaching unmanned forklift according to claim 1, characterized in that: The chassis control module is responsible for the chassis control of the forward-reaching unmanned forklift, and the fork arm control module is responsible for the fork arm control of the forward-reaching unmanned forklift.

3. The high-position cargo picking and placing method of a forward-reaching unmanned forklift according to claim 1 is characterized in that: The visual inspection module is responsible for the identification and position detection of pallets and shelves.

4. A method for picking up and placing goods at a high position by a forward-reaching unmanned forklift according to claim 2, characterized in that: The task control module is responsible for communicating with the scheduling system, splitting tasks, and connecting other modules in series to coordinate work.

5. The high-position cargo picking and placing method of a forward-reaching unmanned forklift according to claim 3 is characterized in that: The safety protection module calculates the obstacle distance around the forward-moving unmanned forklift in real time.

6. The high-position cargo picking and placing method of a forward-reaching unmanned forklift according to claim 1 is characterized in that: S1. When picking up goods, the reach-type unmanned forklift goes to the entry point corresponding to the target warehouse location according to the route planned by the dispatching system. The fork arm is raised to the fork entry height and the pitch angle is adjusted to the horizontal. The rear-view stereo camera is used to recognize the posture of the pallet to be picked up. If the lateral offset value of the pallet to be picked up relative to the reach-type unmanned forklift is less than the maximum lateral travel of the fork arm, the fork arm is moved horizontally so that the fork tip is aligned with the fork entry hole; otherwise, the fork arm is moved horizontally to the maximum travel, and the entry route is locally planned so that the fork tine is located in the middle of the fork entry hole after entry. If the entry line is not replanned, the pallet is entered along the predetermined entry route; Otherwise, it will be stored along the re-planned route; S2. Arrive at the storage point, lift the fork arm to the outbound height, and tilt the fork arm up to the maximum elevation angle to ensure that the goods are stable when outbound. Go outbound in the reverse direction of the route when entering the warehouse. Arrive at the outbound point, lower the fork arm to a safe height for walking, move horizontally to zero position, maintain the elevation angle, and complete the picking up of goods, and go to the delivery point.

7. The high-position cargo picking and placing method of a forward-reaching unmanned forklift according to claim 1 is characterized in that: S1. When releasing the goods, the forward-moving unmanned forklift goes to the entry point corresponding to the target warehouse location according to the route planned by the dispatching system. The fork arm is raised to the entry height and the pitch angle is adjusted to the maximum elevation angle to ensure the stability of the goods when entering the warehouse. The rear-view stereo camera is used to perform posture recognition on the shelf to detect the relative error between the target placement position and the current position of the forklift. If the relative lateral error detected before is less than the maximum lateral travel of the fork arm, the fork arm is moved horizontally to align the goods with the position to be placed; Otherwise, the fork arm is moved horizontally to the maximum stroke, and the local path planning is performed on the warehousing route, so that the goods are exactly located at the waiting position after warehousing. If the warehousing line is not re-planned, the goods are put into the warehouse along the original warehousing line; otherwise, the goods are put into the warehouse along the re-planned route. S2. Upon arrival at the storage point, the fork arm pitch angle is adjusted to a horizontal state; the fork arm is lowered so that the goods fall on the shelf and are shipped out in the reverse direction of the entry route. Upon arrival at the shipping point, the fork arm is lowered to a safe height for walking and moved horizontally to zero position. The goods are released and the dispatching instructions are awaited.

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