Method for automatically checking at least one protected area on an industrial truck

Abstract

A method for automatically checking at least one protective zone on a forklift truck equipped with at least one vehicle-mounted monitoring device that monitors a protective zone laterally and / or in front of the forklift truck and indicates a protective zone violation if an object or person is located in the protective zone, wherein the method comprises the following steps: • Activating the at least one protective zone on the forklift truck, • Picking up and lifting a load carrier, • Checking whether the protective zone(s) are clear, • Lowering the load carrier if the at least one protective zone is clear, • Checking whether a protective zone violation occurs after lowering the load carrier, • Generating a protective zone fault if a protective zone violation has occurred.

Description

[0001] The present invention relates to a method for the automatic testing of at least one protective zone on an industrial truck. The industrial truck is equipped with at least one monitoring device mounted on the vehicle, which monitors a protective zone close to the ground to the side of and / or in front of the industrial truck. The monitoring device detects a violation of the protective zone if an object or a person is located in the protective zone. Currently, it is comparatively complex, especially for automated forklift trucks, to ensure that the load and protective field width match. To do this, the vehicle drives towards or past a precisely positioned test object in order to ensure the dimensions. Current practice provides for the industrial truck to be delivered with a predetermined personnel protection configuration.This means that several protective fields are defined in their dimensions on the sides and / or in front of the industrial truck. After delivery of the truck, it can then be determined on-site whether these predetermined protective fields are compatible with the loads and load carriers used on site. The protective fields are often also determined using the precise positioning of test and inspection bodies, which are then approached for testing purposes.JP 2015 170284 A discloses a method for automatically monitoring at least one protective area, which is equipped with at least one vehicle-mounted monitoring device which monitors a protective area to the side of and / or in front of the industrial truck and indicates a violation of the protective area if an object or a person is located in the protective area, the method comprising the following steps: · Switching on the at least one protective area on the industrial truck, · Picking up and lifting a load carrier.

[0002] The invention is based on the object of providing a method for testing at least one protective area on an industrial truck, which can be carried out with little effort.

[0003] According to the invention, the object is achieved by a method having the features of claim 1. Advantageous embodiments form the subject matter of the subclaims.

[0004] The method according to the invention is intended for the automatic testing of at least one protective zone on an industrial truck. The industrial truck is equipped with at least one monitoring device mounted on the vehicle, which monitors a protective zone close to the ground to the side of and / or in the direction of the load in front of the industrial truck. The monitoring device indicates a violation of the protective zone if an object or a person is located within the protective zone. The following method steps are provided for this purpose: Switching on at least one protective zone on the industrial truck, picking up and lifting a load carrier together with a load that matches the protective field configuration. Checking whether at least one protective zone is clear. If several protective zones are present, priority is given to checking whether all protective fields are uninjured / clear.

[0005] With this picked up and raised load carrier, a check is carried out to determine whether the protective area has been violated by the load carrier or a load on it. If this is the case, a protective area error is displayed, confirming that a protective area violation has occurred. To do this, the load is first checked to see whether the protective area is clear when the load is raised. If there are several protective areas, a check is carried out to see whether all protective areas are clear. This is followed by a step in which the load carrier is lowered, possibly generating a protective area violation. If a protective area violation occurs, a protective area error is generated. The method according to the invention can be carried out automatically, which means that the checking of at least one protective area and the picking up of a load carrier can be carried out automatically without operator intervention.The method according to the invention has the advantage that any conflict between the load carrier used and the specified protection zone of the industrial truck can be checked on-site in a practical situation. This can be done, for example, during operation, when commissioning the industrial truck, or regularly during service appointments. The method can also be performed if there is a change in the load carrier used or the loads to be transported.

[0006] In a preferred development of the method, the automatic test also includes raising and lowering the picked-up load carrier. The lowered position can be close to the ground, lying on the ground, or extending to a predetermined maximum distance. The height to which the load carrier must be raised to check that no violation of the protection zone occurs when the load carrier is raised depends on the geometry and location of the at least one vehicle-mounted monitoring device, which defines a minimum height for the raised position of the load carrier.

[0007] Preferably, the generated protection zone error contains information about where the protection zone violation occurred. This facilitates error correction.

[0008] In a preferred development, it is also provided to check whether a load sensor is responding for the raised load carrier. If the load sensor does not respond to the raised load carrier, a load sensor error is displayed. The functionality of the load sensor can also be checked during service appointments. Checking the load sensor within the scope of the present method is particularly advantageous because a non-responding load sensor either means that it is defective or that there is no load or load carrier on the load-bearing devices. In this case, the test of the protective field dimensions could be completed without errors without this query because there is no load or load carrier on the load-bearing devices, e.g. forks, which could damage the protective field when the load is lowered. However, in this case, no actual check has of course taken place if there is no load or load carrier.There is no load carrier on the load-bearing devices. Querying the load sensor thus provides additional plausibility checks to prevent false positive test results if a load or load carrier was accidentally or intentionally omitted to be picked up before starting the test.

[0009] In a further preferred embodiment, automatic operation of the industrial truck is blocked if one of the errors is present. The two errors are the load sensor error and the protection zone error. In the case of both errors, safe operation, and in particular safe automatic operation, of the industrial truck is not ensured.

[0010] Furthermore, it has proven advantageous to bring the industrial truck to a standstill before checking and lifting the load. This means that the method according to the invention is preferably carried out only with a stationary industrial truck.

[0011] In a further preferred embodiment, a controller is provided which is designed to transfer parameters to the at least one vehicle-mounted monitoring device which define its protection zone. The controller is further designed to adapt the protection zone in the event of an error and to change the parameters by predetermined correction values. In this way, if a load carrier, for example, extends into the protection zone, it can be adjusted accordingly so that no collision with the protection zone occurs. For this step, an error case is considered to be that a protection zone error occurs when the load is lowered. Preferably, the parameters for the correction values ​​are repeatedly changed, either until no more errors occur or until an alternative termination criterion for the adaptation process has been reached. For example, a maximum number of repetitions can be provided as an alternative termination criterion.

[0012] In a preferred development, the load carrier is picked up with a predetermined lateral offset. As a rule, the load carrier can also be picked up with a laterally offset starting from a central position. In the preferred embodiment, it is provided that a predetermined lateral offset, i.e., a maximum lateral offset, can be used in the automatic testing procedure in order to ensure a sufficient distance between the load-bearing device and the protective zone for ongoing operation of the industrial truck, or conversely, to ensure that even with a maximum lateral offset in the direction of the protective field, the field is not violated and no protective zone error occurs.

[0013] Preferably, at least one laser scanner is provided as the monitoring device. Typically, the laser scanner can be mounted fixed to the vehicle with a primary orientation. Its monitoring range can then be adjusted and adjusted in this mounted position using parameters. A fixed mounting not only includes a fixed mounting on a stationary vehicle part, but can also include mounting on a movable vehicle part and also allow for adjustment.

[0014] Preferably, the industrial truck is equipped with a load section that has a height-adjustable load-bearing device. The protected areas are spaced at a predetermined distance laterally from the load-bearing device(s). A laser scanner is preferably provided as the monitoring device for the at least one protected area.

[0015] The protection areas are preferably personal protection areas, in the event of an infringement of which the industrial truck is immediately put into a safe state, for example switched off or stopped.

[0016] The proposed procedure is specifically designed for automated industrial trucks. Figure 1 shows a total of eight different situations that can occur during the inspection of a load carrier and Figure 2 shows a flow chart of the automatic process.

[0017] Figure 1 shows a schematic top view of an industrial truck 10 with a drive part 12 and a load-bearing device 14. The area 16 intended for a load carrier is shown in dashed lines. Two hatched areas 18, 20 are provided around this area on the sides of the industrial truck. The protection areas 18, 20 are generated by one or two laser scanners on the industrial truck 10. Figure 1Figure 1 shows the situation in which the industrial truck 10 creates the intended protective areas 18, 20, which are located outside the area 16 intended for the load carrier. The fact that in the Figure 1 The fact that no violation of the protective zone is expected in the configuration shown is symbolically represented by fields 22, 24. Fields 22, 24 can, for example, be integrated into the display for the operator or simply symbolize special memory locations in a control system. It is assumed that when checking whether fields 22, 24 are violated, the load-bearing device 14 is at a height at which a picked-up load carrier intersects the scanning plane of the laser scanners and would therefore trigger the protective fields 20, 18 given the corresponding size of the load carrier.

[0018] Figure 1shows in illustration (2) essentially the situation from illustration (1), in which a load carrier 26 is accommodated. The load carrier 26 is positioned in the predetermined area 16, so that despite a height of the load carrier in the area of ​​the protective fields 18, 20, there is still no violation of a protective area 18 or 20. The corresponding states 22 and 24 continue to indicate that no violation has occurred. The further display 28, which is schematically shown in the middle of the load carrier 26, relates to the state of the load sensor. This is additionally shown in Figure 1(3a). In illustration (3a), a load sensor detects when the load-bearing device 14 is lifted that it is empty, i.e., that no load or load carrier (pallet or similar) has been picked up. The load-bearing device is lifted in order to check that the scanning area of ​​the laser scanners or the protective fields 18, 20 are clear when the load 26 is picked up. Since it is intended that the load-bearing device is only lifted when the load carrier is picked up, an error has occurred here, which is shown as 'Not OK 28'. This error can be caused by a defective load sensor or by the load carrier 26 not actually being picked up.

[0019] Illustration (3b) shows the situation where an object 30 is located in the protection zone 18. In this case, a signal Not OK 22' is generated, which interrupts the automatic continuation of the procedure. The error cases of missing load carrier and object in the protection zone prevent automatic execution of the procedure. The reason for this is that a successful check of the load carrier dimension can only be carried out if a) A load carrier has been picked up at all, which is not the case in case (3a) (and also 3b), and b) the protective area 18, 20 must be free of other objects so that when the protective fields 18, 20 are triggered, it is clearly established that the triggering was caused by the load carrier 26. The checking of the protective fields 18, 20 for the presence of objects 30 is carried out with the load-bearing device raised so that the picked-up load carrier is above the scanning planes of the laser scanners.

[0020] Figure 1 (2a) shows a situation in which a significantly smaller load carrier 32 is included. The smaller load carrier 32 has a greater distance from the protection areas 18 and 20.

[0021] Figure 1 (2b) shows a situation in which the small load carrier 32 is mounted off-center on the load-bearing means with a lateral offset 34. The illustration in (2b) shows that the smaller load carrier 32 is still at a distance from the protection area 18, in the direction of which the lateral offset 34 occurred. This situation is therefore still acceptable.

[0022] The representation (3c) in Figure 1shows a situation where a large load carrier 36 is mounted. The width of the illustrated load carrier 36 is such that it violates the respective protection zones 18 and 20 in both zones 38 and 40. This clearly represents a situation in which the protection zones 18 and 20 are arranged too close to the load-bearing means 14.

[0023] Of particular interest is the one shown in Figure (3d) of Figure 1illustrated variant, in which the load-bearing means 36 is arranged off-center. Due to the off-center arrangement of the load carrier 36, the situation arises that there is no violation of the protective area for the protective area 18. Only zone 42 violates the protective area 20. In the situation from Figure 3b, when the protective areas are adjusted, the protective area 18 can remain unchanged, while the protective area 20 is continued further outwards, i.e. from the load carrier 36. In an alternative embodiment, it is also possible to set the protective area 18 further outwards in this situation, for example because a symmetrical arrangement of the protective areas relative to the load-bearing means is desired.

[0024] Figure 2explains the sequence of the method according to the invention using a specific exemplary embodiment. In a start step 100, the function is activated via an operating element (HMI) on the industrial truck. Following activation 100, the method section for checking the plausibility of the parameters for the protected area begins. A first query 104 checks whether the vehicle is stationary. If the vehicle is stationary, a second query 106 checks whether a load is present. This check step also includes the situation in which an empty load carrier is arranged on the load-bearing means. The second query 106 also recognizes the empty load carrier as a load. This step particularly includes lifting the load, since only in this case is the load not resting on the ground and can be sensed by the load sensor.In a third query 108, if a load was detected in the second query 106, a third query 108 determines whether the protected areas are clear. This step occurs with the load raised in order to be able to clearly attribute protected area violations to foreign objects placed in the protected area, i.e., objects that are not the load or the load carrier itself. For this purpose, the load and the load carrier are raised to a height above the scanning plane of the laser scanners. If the third query 108 can be confirmed, the plausibility check is successfully confirmed in method step 110.

[0025] Further steps are provided in the plausibility check process with method steps 102 to 110. If the first query 104 does not bring the vehicle to a standstill, the industrial truck is brought to a standstill in step 112. Once the standstill has been reached, the process returns to the beginning of the plausibility check 102.

[0026] If the second query 106 determines that no load or load carrier is present, step 114 determines that a load pickup is taking place. In this case, load pickup also includes the situation in which a load sensor is activated or replaced in the event that a missing load is detected even though the load carrier has been picked up by the load-bearing device.

[0027] If a protective field violation is detected in step 108, a corresponding error message is generated so that the test area can be cleared in step 116 and the protective field check can continue. Detection of whether the protective area is clear occurs when the load carrier and / or load are raised above the scanning plane.

[0028] After successful plausibility check in step 110, the lifting and lowering of the loads can be checked in a second section of the method. In step 118, this method begins with the lowering of the load. A fourth query 120 checks whether the load has been completely lowered. This can be done, for example, by a lifting height sensor. In principle, it is also possible to carry out the method if the load is not completely lowered. The only thing that matters is that the height of the load or load carrier is set so that the scan plane of the sensors close to the ground is intersected. Once the load has been lowered, a fifth query 122 checks whether one of the protection zones has been violated. If the protection zone has been violated, it is determined in method step 124 that the test regarding lifting and lowering could not be carried out successfully.This has two consequences: First, an error message is generated in step 126, which, if possible, also contains information about which protection zone was violated. A further consequence is step 128, in which the industrial truck's permission for automatic operation is revoked. This means that until the plausibility check is successful, the truck can only be operated and driven manually. Blocking automatic operation 128 terminates error case 130. If the fifth query 122 does not determine that one of the protection zones is violated, step 132 determines that the plausibility check with the load or load carrier was successful. This terminates the process in step 134.

[0029] A special feature of the method is that in the fourth query 120 for load lowering, a repetition loop 136 is provided for the event that the load has not been lowered or has not yet been lowered. For this purpose, an increment n is defined. If it is determined in the fourth query 120 that the load has not been lowered, the increment is increased by 1. If it is determined in 136 that the increment is less than or equal to a maximum number, the method returns to the lowering step 118 and attempts to continue lowering the load. If, on the other hand, it is determined that the increment is greater than the maximum number, the industrial truck is de-enabled for automatic operation in step 128. This can be due, for example, to an obstacle located under the load-bearing device or under the load carrier and preventing complete lowering. List of reference symbols

[0030] 10Industrial truck 12Drive part 14Load-bearing device 16Area 18Hatched protection area 20Hatched protection area 22Field 24Field 26Load carrier 28Display 28'Error display Not OK 28"Error display Not OK 30Object 32Small load carrier 34Lateral offset 36Large load carrier 38Zone 40Zone 42Zone 100Start step 102Procedure step 104First query 106Second query 108Third query 110Procedure step 112Procedure step 114Procedure step 118Procedure step 120Fourth query 122Fifth query 124Procedure step 126Procedure step 128Procedure step 130Error case 132Procedure step 134Procedure step 136Repeat loop

Claims

1. A method for automatically checking at least one protected area (18, 20) on an industrial truck (10), which is equipped with at least one monitoring apparatus that is firmly mounted on the vehicle, monitors one protected area (18, 20) laterally of and / or one protected area in front of the industrial truck (10), and indicates a violation of the protected area when an object or a person is located in the protected area (18, 20), wherein the method has the following steps: • Switching on the at least one protected area (18, 20) on the industrial truck (10), • Picking up and lifting a load carrier (26), • Checking (108) whether the protected area or areas (18, 20) are clear, • Lowering the load carrier when the at least one protected area is clear, • Checking whether a violation of the protected area occurs after the load carrier (26) is lowered, • Generating a protected area error when a violation of the protected area has occurred.

2. The method according to claim 1, characterized in that the lifting and lowering of the picked-up load carrier (26) is performed along a predetermined path, wherein a lowered position can extend to the floor or has a predetermined maximum distance from the floor and a lifted position has a predetermined minimum distance from the floor.

3. The method according to claim 2, characterized in that • The generated protected area error contains information about where the violation of the protected area has occurred.

4. The method according to claim 2 or 3, characterized by • Checking whether a load sensor indicates the lifted load carrier (26), in particular before the load carrier is lowered to check whether a violation of the protected area occurs, • Indicating a load sensor error if the load sensor does not respond to the lifted load carrier (26).

5. The method according to one of the preceding claims, characterized by • Disabling an automatic operating mode for the industrial truck (10) if an error has occurred.

6. The method according to one of claims 1 to 5, characterized by • Halting the industrial truck (10) until it is stationary before the picked-up load is lifted.

7. The method according to one of claims 1 to 6, characterized in that a control is provided, which is designed to transmit parameters to the at least one vehicle-mounted monitoring apparatus that define its protected area, wherein the control is also designed to adapt the corresponding protected area in the event of a protected area error and to modify the parameters by a predetermined correction value.

8. The method according to claim 7, characterized in that the parameters for the correction value are repeatedly modified, either until an error for adapting the at least one protected area no longer occurs or until a maximum number of repetitions has been reached.

9. The method according to one of claims 1 to 8, characterized in that the load carrier is picked up with a predetermined lateral offset.

10. The method according to one of claims 1 to 9, characterized in that a laser scanner is provided as the monitoring apparatus.

11. The method according to one of claims 1 to 10, characterized in that the industrial truck (10) has a load part with a height-adjustable load-carrying means (14), and the protected areas (18, 20) extend at a predetermined distance laterally of the load-carrying means.

12. The method according to claim 11, characterized in that the at least one protected area (18, 20) is one or more personal protection areas, upon violation of which the industrial truck (10) is stopped.

13. The method according to one of claims 1 to 12, characterized in that the industrial truck is an automated industrial truck (10).

14. The method according to one of claims 1 to 13, characterized in that the checking of the at least one protected area (18, 20) takes place during initial commissioning and / or during maintenance of the industrial truck (10).

15. The method according to one of claims 1 to 14, characterized in that the automatic checking of the protected areas is performed in automatic mode during normal operation by random sampling.

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