AGV cargo detection method and system

Abstract

The AGV cargo detection method comprises the following steps that a distance detection module is installed on a pallet fork of a vehicle, the distance detection module is arranged to face cargos and obliquely emit detection signals in the height direction, and an included angle phi is formed between the signal emission direction of the distance detection module and the fork entering direction of the pallet fork; the distance information L1 of the goods detected by the distance detection module when the pallet fork moves in the fork entering direction is obtained, and the height of the goods is calculated in combination with the included angle phi; and acquiring the speed of the vehicle and the time points before and after the fork enters, and calculating the size information of the goods in combination with the distance information L1 and the included angle phi. According to the invention, the height of the goods and the size in the fork entering direction can be rapidly calculated through distance detection, and the use safety of the AGV is effectively improved.

Description

Technical Field

[0001] The present invention relates to the field of AGVs, and particularly to a method and system for detecting goods of an industrial vehicle. Background Art

[0002] With the increasing popularity of AGV forklifts, unmanned forklifts will encounter difficulties in automatically identifying the length and width of goods or pallets and the height of goods during actual use. From the perspective of the height of goods, once the goods are too high, there will not only be a problem of underloading, but also a risk of goods tipping over due to the excessive height of the goods. For the length of goods: once the position of the fork entry is incorrect, for example, the length of the goods along the fork entry direction is too long, it will cause the load center of the goods to become longer, resulting in a decrease in the stability of the AGV forklift and even a risk of tipping over. The currently popular intelligent vision technology has high requirements for algorithms, high costs and large errors due to factors such as complex forklift behaviors, unclear visual features, and vehicle body occlusion. Summary of the Invention

[0003] The main purpose of the present invention is to overcome the defects existing in detecting the height or size of goods in the prior art, and to propose a method and system for detecting goods of an AGV, which can quickly calculate the height of the goods and the size in the fork entry direction through distance detection, and effectively improve the safety of AGV use.

[0004] The present invention adopts the following technical solutions:

[0005] A method for detecting goods of an AGV, comprising the following steps:

[0006] Install a distance detection module on the fork of the vehicle, and set the distance detection module to emit detection signals obliquely in the height direction towards the goods, and the signal emission direction of the distance detection module and the fork entry direction of the fork have an included angle φ;

[0007] Obtain the distance information L1 between the distance detection module and the goods detected when the fork moves in the fork entry direction, and calculate the height of the goods in combination with the included angle φ;

[0008] Obtain the vehicle speed and the time points before and after the fork entry of the vehicle, and then calculate the size information of the goods in combination with the distance information L1 and the included angle φ.

[0009] The calculation method of the height of the goods is specifically as follows:

[0010] Calculate the local height H1 of the goods by combining the distance information L1 and the included angle φ according to the trigonometric theorem, and add the local height H1 to the known installation height H2 of the distance detection module to obtain the height H of the goods, where H = H1 + H2.

[0011] It further includes: obtaining the vehicle speed and the time points before and after the forklift forks enter the goods, calculating the first displacement information L2 of the goods in the fork entering direction, using the distance information L1 in combination with the included angle φ to calculate the initial distance information L0 of the goods, and obtaining the size information L3 of the goods according to the difference between the first displacement information and the initial distance information, where L3 = L2 - L0.

[0012] Obtaining the vehicle speed and the time points before and after the forklift forks enter the goods to calculate the first displacement information L2 of the goods in the fork entering direction, specifically: obtaining the time point t1 when the distance detection module first detects the distance information of the goods before the forklift forks enter, obtaining the time point t2 when the distance detection module first fails to detect the distance information of the goods after the forklift forks enter, and calculating the first displacement information L2 of the goods as L2 = V(t2 - t1) in combination with the vehicle speed V.

[0013] The initial distance information refers to the distance between the corresponding goods and the distance detection module in the fork entering direction when the distance detection module first detects the distance information L1; combining the distance information L1 and the included angle φ and using the trigonometric theorem to calculate the initial distance information L0 = L1 * cosφ of the goods.

[0014] It further includes the verification of the goods size, specifically: obtaining the time point after the forklift forks enter the goods to calculate the second displacement information L4 of the goods on the forklift forks, and then calculating the difference between the distance L5 between the distance detection module and the forklift fork frame and the second displacement information L4 to obtain the size information L3' = L5 - L4 of the goods; comparing the size information L3' with the size information L3 to determine whether the verification passes.

[0015] Obtaining the time point t3 from when the forklift forks enter until the goods are in place, and calculating the second displacement information L4 of the goods on the forklift forks as L4 = V * (t3 - t2) in combination with the time point t2, the time point t3, and the vehicle speed V.

[0016] Comparing the size information L3' with the size information L3 to determine whether the verification passes, including determining whether the size information L3' is equal to the size information L3. If so, the verification passes; or determining whether the difference between the size information L3' and the size information L3 is within the set range. If so, the verification passes.

[0017] It further includes the following judgment according to the height H of the goods and the size information L3:

[0018] If the height H of the goods exceeds the set height threshold, control the vehicle to stop the fork entering and send a prompt message; otherwise, control the vehicle to continue the fork entering.

[0019] If the size information L3 of the goods exceeds the set size threshold, control the vehicle to fork out and move to the other side adjacent to the goods, and recalculate the size information of the goods.

[0020] A goods detection system for an AGV, comprising

[0021] A distance detection module, arranged to face the goods and emit detection signals obliquely along the height direction, and the signal emission direction of the distance detection module has an included angle φ with the fork-in direction of the fork;

[0022] A calculation and judgment module for executing the goods detection method of the AGV.

[0023] As can be seen from the above description of the present invention, compared with the prior art, the present invention has the following beneficial effects:

[0024] 1. In the present invention, a distance detection module is installed on the fork of the vehicle to obtain the distance information L1 between the distance detection module and the goods detected when the fork moves along the fork-in direction, and the height of the goods is calculated in combination with the included angle φ, that is, the height of the goods can be effectively detected before fork-in, and the implementation is easy, the calculation method is simple and the cost is low.

[0025] 2. In the present invention, it also includes calculating the first displacement information of the goods in the fork-in direction, and calculating the initial distance information of the goods by using the distance information in combination with the included angle φ, and obtaining the size information of the goods according to the difference between the first displacement information and the initial distance information, so as to realize the synchronous and effective calculation of the height and size information of the goods.

[0026] 3. In the present invention, it also includes the verification of the goods size, that is, the verification is realized by comparing the calculation results of two goods size calculation methods, so as to ensure that the calculation result of the goods size is more accurate and reliable.

[0027] 4. In the present invention, when the height of the goods exceeds the set height threshold, control the vehicle to stop fork-in and send a prompt message to avoid the risk of tipping caused by the excessive height of the goods; when the size information of the goods exceeds the set size threshold, control the vehicle to fork out and move to the other side adjacent to the goods and recalculate the size information of the goods, that is, the long and short sides of the goods can be identified to prevent the risk caused by incorrect fork-in. Description of the Drawings

[0028] Figure 1 It is a schematic diagram of the distance detection module of the present invention installed on the fork;

[0029] Figure 2 It is a schematic diagram of the principle for calculating the height of the goods;

[0030] Figure 3 It is a schematic diagram before and after the goods are forked in;

[0031] Figure 4 It is a schematic diagram of the goods in place;

[0032] Wherein:

[0033] 10. Vehicle, 11. Fork, 12. Fork frame, 13. In-place sensor, 20. Distance detection module, 30. Goods.

[0034] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. Specific embodiments

[0035] The present invention will be further described below through specific embodiments.

[0036] In the present invention, for terms such as "first", "second", "third", etc., they are only used to distinguish similar objects, and do not have to be used to describe a specific order or sequence, nor can they be understood as indicating or implying relative importance. In the description, the orientation or positional relationship indicated by "up", "down", "left", "right", "front" and "rear" is based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of describing the present invention, rather than indicating or implying that the device referred to must have a specific orientation, be constructed and operated in a specific orientation, so it cannot be understood as a limitation on the protection scope of the present invention. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0037] In addition, in the description of the present application, unless otherwise specified, "a plurality" means two or more. "And / or" describes the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. The character " / " generally represents an "or" relationship between the associated objects before and after.

[0038] The present invention provides a method for detecting goods of an AGV, including the following: installing a distance detection module 20 on the fork 11 of the vehicle 10, and setting the distance detection module 20 to emit detection signals obliquely along the height direction towards the goods 30. The signal emission direction of the distance detection module 20 and the fork-in direction of the fork 11 have an included angle φ; obtaining the distance information L1 between the distance detection module 20 and the goods 30 detected when the fork 11 moves along the fork-in direction, and calculating the height of the goods 30 in combination with the included angle φ; obtaining the vehicle speed of the vehicle 10 and the time points before and after the fork 11 forks in, and then calculating the size information of the goods 30 in combination with the distance information L1 and the included angle φ.

[0039] Wherein, see Figure 1, the distance detection module 20 is installed at one end of the fork 11 in the fork-in direction away from the vehicle 10, that is, installed near the end of the fork 11, and is arranged not to affect the fork-in of the fork 11. The number of the distance detection modules 20 can be one or two, and two are taken as an example in the figure. The specific value of the included angle φ can be set or adjusted according to actual needs, that is, the distance detection module 20 can be fixed on the fork 11 or installed on the fork 11 with an adjustable angle. For example, the included angle φ is less than 90°, and the included angles φ of the two distance detection modules 20 can be the same or different. The distance detection module 20 can adopt a laser ranging sensor, an infrared ranging sensor, etc.

[0040] When the vehicle 10 with the distance detection module 20 moves in the fork-in direction or out of the fork, the distance between the distance detection module 20 and the goods 30 will gradually decrease or gradually increase. The distance detection module 20 can be activated when the vehicle 10 enters the picking point. When the vehicle 10 moves in the fork-in direction until the detection signal emitted by the distance detection module 20 hits the goods 30 for the first time, the distance detection module 20 will obtain the distance information L1. This distance information L1 is the distance information in the detection signal emission direction, and this distance information L1 is used to calculate the height of the goods 30. When both sides of the fork-in direction of the goods 30 cross the distance detection module 20 after the fork 11 forks into the goods 30, the distance detection module 20 cannot detect the distance information of the goods 30.

[0041] The calculation method of the height of the goods 30 in the present invention is specifically as follows:

[0042] See Figure 2 , combining the distance information L1 detected by the distance detection module 20 and the known included angle φ, and calculating the local height H1 of the goods 30 according to the trigonometric theorem. Adding the local height H1 to the known installation height H2 of the distance detection module 20 to obtain the height H of the goods 30 = H1 + H2.

[0043] Among them, if two distance detection modules 20 are set on the fork 11 and the included angles φ of the two distance detection modules 20 are the same, the heights of two goods 30 can be calculated, and the average value can be taken as the height of the goods 30.

[0044] The present invention also includes a method for calculating the size of the goods 30:

[0045] See Figure 3 , obtaining the vehicle speed of the vehicle 10 and the time points before and after the fork 11 forks in to calculate the first displacement information L2 of the goods 30 in the fork-in direction, using the distance information L1 combined with the included angle φ to calculate the initial distance information L0 of the goods 30, and obtaining the size information L3 of the goods 30 = L2 - L0 according to the difference between the first displacement information L2 and the initial distance information L0.

[0046] Among them, the size information of the goods 30 refers to the side length of the goods 30 in the fork insertion direction of the forks 11. By calculating the side length of the goods 30 to be inserted, it can be determined whether the forks 11 can be inserted smoothly. The vehicle 10 is equipped with a speed encoder, and the vehicle speed of the vehicle 10 can be obtained in real time through the speed encoder. The vehicle speed of the vehicle 10 and the time points before and after the insertion of the forks 11 are used to calculate the first displacement information L2 of the goods 30 in the insertion direction. Specifically: obtain the time point t1 when the distance detection module 20 first detects the distance information L1 from the goods 30 before the insertion of the forks 11, obtain the time point t2 when the distance detection module 20 first fails to detect the distance information from the goods 30 after the insertion of the forks 11, and calculate the first displacement information L2 of the goods 30 as L2 = V(t2 - t1) by combining the vehicle speed V of the vehicle 10.

[0047] The initial distance information of the present invention refers to the distance between the corresponding goods 30 and the distance detection module 20 in the fork insertion direction when the distance detection module 20 first detects the distance information L1. The time point t2 when the distance detection module 20 first fails to detect the distance information from the goods 30 after the insertion of the forks 11 also represents that both sides of the goods 30 in the fork insertion direction are completely located on the forks 11. The initial distance information L0 of the goods 30 is calculated by combining the distance information L1 and the angle φ according to the trigonometric theorem as L0 = L1 * cosφ.

[0048] In the present invention, for the two distance detection modules 20, the size information L3 of the two goods 30 can be calculated as L3 = L2 - L0, and the average value can be taken as the size information of the goods 30.

[0049] In order to further confirm whether the calculated size information of the goods 30 is correct, the present invention also includes the verification of the size of the goods 30, that is, calculating the size information of the goods 30 by another method, and comparing the calculated value with the previous size information L3 to achieve verification and ensure the accuracy of the measurement. The specific method of the other calculation is: obtain the time point after the insertion of the forks 11 to calculate the second displacement information L4 of the goods 30 on the forks 11, and then calculate the difference between the distance L5 between the distance detection module 20 and the fork carriage 12 and the second displacement information L4 to obtain the size information L3' of the goods 30 as L3' = L5 - L4; compare the size information L3' with the size information L3 to determine whether the verification is passed.

[0050] Among them, the second displacement information L4 of the goods 30 on the fork 11 refers to the relative displacement information from when the goods 30 are completely on the fork 11 (i.e., the time point t2 mentioned above), and the fork 11 continues to enter the fork until the goods 30 are in place. Whether the goods 30 are in place can be detected by the in-place sensor 13 provided on the fork carriage 12, and the distance L5 is also the distance between the in-place sensor 13 and the distance detection module 20. Obtain the time point t3 when the fork 11 enters the fork until the goods 30 are in place, and combine the time point t2, the time point t3, and the vehicle speed V to calculate the second displacement information L4 of the goods 30 on the fork 11 = V*(t3 - t2).

[0051] Further, compare the calculated dimension information L3' with the dimension information L3 to determine whether the verification is passed, including determining whether the dimension information L3' is equal to the dimension information L3. If so, the verification is passed; or determining whether the difference between the dimension information L3' and the dimension information L3 is within the set range. If so, the verification is passed. This set range can be set according to actual needs and is not limited here.

[0052] In the present invention, after determining the height and dimension information of the goods 30, it further includes making the following judgments according to the height H of the goods 30 and the dimension information L3:

[0053] Since the height of the goods 30 can be calculated before the fork 11 enters the fork, if the height of the goods 30 exceeds the set height threshold, the vehicle 10 is controlled to stop entering the fork and a prompt message is sent, and the pick-up error information is uploaded for on-site personnel to handle; otherwise, the vehicle 10 is controlled to continue entering the fork.

[0054] Since the dimension of the goods 30 is calculated during the process of the fork 11 entering the fork, if the dimension of the goods 30 exceeds the set dimension threshold, the vehicle 10 is controlled to retract the fork and move to the other side adjacent to the goods 30 and recalculate the dimension information of the goods 30. If not, the vehicle 10 is controlled to continue entering the fork or enter the next action.

[0055] The goods 30 usually have a long side or a short side. If the short side fails to enter the fork, the vehicle 10 can be controlled to move to the long side to enter the fork. The method of the present invention can be applied to a counterbalanced forklift or a warehousing AGV forklift. The AGV forklift can also perform path planning and pick up goods from different sides of the pallet or the goods 30 according to needs. The present invention can effectively calculate the height of the goods 30, thereby avoiding the tipping risk caused by the excessive height of the goods 30, and can also effectively identify the long and short sides of the goods 30 or the pallet, preventing the risk caused by incorrect fork entry.

[0056] A goods detection system for an AGV, including

[0057] The distance detection module 20 is set to emit detection signals obliquely in the height direction towards the goods 30, and there is an included angle φ between the signal emission direction of the distance detection module 20 and the fork-in direction of the fork 11. The distance detection module 20 is installed at one end of the fork 11 in the fork-in direction away from the vehicle 10, that is, installed at a position close to the end of the fork 11. The distance detection module 20 can adopt a laser ranging sensor, an infrared ranging sensor, etc. The distance information L1 detected by the distance detection module 20 is the distance information in the signal emission direction.

[0058] The calculation and judgment module is used to execute the above-mentioned goods detection method of an AGV, that is, it includes the above-mentioned steps of calculating the height of the goods 30 and the step of calculating the dimension information of the goods 30.

[0059] The calculation and judgment module can also be used to realize the verification of the size of the goods 30, that is, it can realize the synchronous calculation of the height, size of the goods 30 and the verification of the size of the goods 30.

[0060] The above is only the specific implementation manner of the present invention, but the design concept of the present invention is not limited thereto. Any non-substantive modification of the present invention using this concept shall fall within the scope of infringement of the protection scope of the present invention.

Claims

1. A cargo detection method for AGV, characterized in that: These include: A distance detection module is installed on the fork of the vehicle, and the distance detection module is set to emit a detection signal towards the cargo and tilted in the height direction, and the signal emission direction of the distance detection module and the fork entry direction of the fork have an angle φ; Acquire the distance information L1 between the distance detection module and the cargo when the cargo fork moves along the fork entry direction, and calculate the height of the cargo in combination with the angle φ; The speed of the vehicle and the time points before and after the fork engages are obtained, and then the size information of the cargo is calculated in combination with the distance information L1 and the angle φ.

2. The cargo detection method of AGV according to claim 1, characterized in that: The calculation method of the height of the cargo is as follows: The distance information L1 and the angle φ are combined with trigonometric theorem to calculate the local height H1 of the cargo, and the local height H1 is added to the known installation height H2 of the distance detection module to obtain the height H=H1+H2 of the cargo.

3. The cargo detection method of AGV according to claim 1, characterized in that: Also includes: The speed of the vehicle and the time points before and after the fork engages are obtained to calculate the first displacement information L2 of the cargo in the fork engagement direction, the distance information L1 is combined with the angle φ to calculate the initial distance information L0 of the cargo, and the size information L3=L2-L0 of the cargo is obtained based on the difference between the first displacement information and the initial distance information.

4. The cargo detection method of AGV according to claim 3, characterized in that: The vehicle speed and the time points before and after the fork engages are obtained to calculate the first displacement information L2 of the cargo in the fork engaging direction, specifically: the time point t1 when the distance detection module first detects the distance information to the cargo before the fork engages is obtained, and the time point t2 when the distance detection module first fails to detect the distance information to the cargo after the fork engages is obtained, and the first displacement information L2=V(t2-t1) of the cargo is calculated in combination with the vehicle speed V.

5. The cargo detection method of AGV according to claim 3, characterized in that: The initial distance information refers to the distance between the corresponding goods and the distance detection module in the fork direction when the distance detection module detects the distance information L1 for the first time; the distance information L1 and the angle φ are combined with the trigonometric function theorem to calculate the initial distance information L0=L1*cosφ of the goods.

6. The cargo detection method of AGV according to claim 3, characterized in that: It also includes verification of cargo size, specifically: obtaining the time point after the fork enters the fork, calculating the second displacement information L4 of the cargo on the fork, and then calculating the difference between the distance L5 between the distance detection module and the fork frame and the second displacement information L4 to obtain the cargo size information L3'=L5-L4; comparing the size information L3' with the size information L3 to determine whether the verification is passed.

7. The cargo detection method of AGV according to claim 6, characterized in that: The time point t3 when the fork is engaged until the cargo is in place is obtained, and the second displacement information L4=V*(t3-t2) of the cargo on the fork is calculated by combining the time point t2, the time point t3 and the vehicle speed V.

8. The cargo detection method of AGV according to claim 6, characterized in that: Compare the size information L3' with the size information L3 to determine whether the verification is passed, including determining whether the size information L3' is equal to the size information L3, if so, the verification is passed; Or determine whether the difference between the size information L3' and the size information L3 is within a set range. If so, the verification is passed.

9. The cargo detection method of AGV according to claim 3, characterized in that: It also includes making the following judgments based on the height H and size information L3 of the goods: If the height H of the cargo exceeds the set height threshold, the vehicle is controlled to stop forking and a prompt message is issued; otherwise, the vehicle is controlled to continue forking; If the size information L3 of the cargo exceeds the set size threshold, the vehicle is controlled to fork out and move to the other side adjacent to the cargo and recalculate the size information of the cargo.

10. An AGV cargo detection system, characterized in that: include A distance detection module is configured to transmit a detection signal toward the cargo and tilted in the height direction, wherein the signal transmission direction of the distance detection module and the fork entry direction of the cargo fork form an angle φ; A calculation and judgment module, used to execute the cargo detection method of an AGV according to any one of claims 1 to 9.

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