Driverless transport vehicle and methods for monitoring a driverless transport vehicle

Abstract

The invention relates to a driverless transport vehicle, wherein the transport vehicle comprises a control device (10) for controlling an electric drive system of the transport vehicle. The transport vehicle is designed to transport a goods carrier. The transport vehicle has a first goods carrier recognition device (12) for recognizing the transported goods carrier as a specific goods carrier and / or as a goods carrier of a specific goods carrier type. The control system further comprises a monitoring device (14), in particular a safety controller, wherein the monitoring device (14) and the control device (10) are connected by a data connection (16).The transport vehicle has a second carrier recognition device (18) independent of the first carrier recognition device (12) for recognizing the transported carrier as a specific carrier and / or as a carrier of a specific carrier type, and the monitoring device (14) is designed to perform a comparison of the result of the recognition of the transported carrier by the first carrier recognition device (12) with the result of the recognition of the transported carrier by the second carrier recognition device (18).

Description

[0001] The invention relates to a driverless transport vehicle according to the preamble of claim 1 and a method for monitoring such a driverless transport vehicle.

[0002] Automated guided vehicles are known from the state of the art. These types of vehicles are used to transport loads. Automated guided vehicles are used primarily in confined spatial areas, for example, within a production facility and / or a warehouse.

[0003] Such automated guided vehicles pose a significant risk to people. Persons who enter the path of such automated guided vehicles can suffer severe and, in extreme cases, fatal injuries if the vehicle is not stopped as soon as a person enters its path. The same naturally applies to other objects that may be in the path of the vehicle and that could be damaged by the vehicle and / or sustain damage. However, it is the potential risk to people in particular that leads to the highest demands being placed on the operational safety of such vehicles.

[0004] Such driverless transport vehicles are known in practice and are designed to transport a goods carrier. Such goods carriers, for example pallets, can be designed to be loaded with different loads. When controlling such a driverless transport vehicle, it is particularly important, with regard to safety, to determine which goods carrier is being moved by the transport vehicle. The driving behavior of the driverless transport vehicle depends on the load carried on the goods carrier, both its mass and its dimensions. In particular, braking distances can be considerably longer for large loads than for small loads. For safety reasons, if the load being transported and / or its dimensions are unknown, it is therefore fundamentally necessary to control the vehicle as if the largest possible load with the largest possible dimensions were being transported.

[0005] DE 20 2022 103 511 U1 discloses an autonomously driving transport system for transporting pallets and / or lattice boxes. The transport system comprises a receiving device for receiving the pallet and / or lattice box and has a drive unit and a control device.

[0006] DE 10 2021 109 613 A1 discloses a method for load detection in an industrial truck and a system for carrying out the method.

[0007] US 2023 / 0 226 697 A1 shows a material transport device with a transfer hand for receiving a material from a counter device or for delivering the material to the counter device, with an unmanned transport vehicle that moves along a predetermined path, a main body that is arranged on the unmanned transport vehicle, and a transfer hand that is arranged inside the main body, protrudes at least partially from the main body, loads or unloads the material and has a positioning sensor that detects a mark arranged on the counter device and determines a position difference with the counterpart device, and the material transport device determines a position of the transfer hand based on the transfer hand on the basis of the positioning sensor determined by the positioning sensor.

[0008] US 2023 / 0 185 314 A1 shows a logistics system with a leading and a following truck. The leading vehicle is configured for autonomous driving, while the following vehicle is not. The leading vehicle contains sensors that cover an environmental monitoring area. The leading and following vehicles each contain a transceiver for operating a wireless data connection between the leading and following vehicles. The leading and following vehicles are configured so that the leading vehicle remotely controls the following vehicle via the wireless data connection.

[0009] US 2019 / 0 163 188 A1 discloses an operating system for a material handling vehicle that includes a tag layout in which a plurality of entry / exit tag sets are arranged along a travel path at various entry / exit thresholds of a restricted navigation zone. Each entry / exit tag set includes an enable tag, a restrict tag, and an indicator tag.

[0010] EP 4 195 125 A1 discloses a logistics system comprising a leading industrial truck and at least one following industrial truck, wherein the leading industrial truck is equipped and configured for autonomous operation and the following industrial truck is not equipped and configured for autonomous operation. The leading industrial truck includes an environmental monitoring system that defines an environmental monitoring area.

[0011] EP 3 992 058 A1 shows a method for transporting a goods carrier by means of an industrial truck that can be operated at least partially automatically.

[0012] In order to achieve greater efficiency with such driverless transport vehicles, such a driverless transport vehicle can be equipped with a goods carrier recognition device for recognizing the transported goods carrier as a specific goods carrier and / or as a goods carrier of a specific goods carrier type. The recognition of a specific goods carrier can enable the determination of the mass of the load carried on this goods carrier and / or its dimensions, and the determination of the goods carrier type can at least enable the maximum mass of the load that can be carried on this goods carrier and / or its largest possible dimensions. When controlling the transport vehicle, a lower mass and / or dimension of the load can be used as a basis. This makes higher speeds possible, for example, because shorter stopping distances can be expected.Furthermore, any sensor arrangements on such a transport vehicle designed to detect obstacles within a monitoring area around the transport vehicle only need to monitor a smaller monitoring area. This is because the extent of the required monitoring area correlates with the stopping distance.

[0013] However, if these advantages are fully exploited, the detection of the goods carrier or the type of goods carrier becomes demanding, as this is ultimately a highly safety-relevant function. Accordingly, the components involved, especially the sensors and / or control systems of the automated guided vehicle, must meet the relevant safety requirements. This significantly increases the cost of these components.

[0014] The invention is therefore based on the object of demonstrating a driverless transport vehicle and a method for monitoring such a driverless transport vehicle, which enable reliable detection of the goods carrier and / or the goods carrier type and can be implemented using components that are as cost-effective as possible.

[0015] This object is achieved by a driverless transport vehicle and a method for monitoring such a driverless transport vehicle having the features of the independent claims. The features of the dependent claims relate to advantageous embodiments.

[0016] The transport vehicle, the control of which is the subject of the method, has an electric drive system with a control device for controlling the electric drive system of the transport vehicle. The drive system is controlled by means of the control device.

[0017] The transport vehicle is designed to transport a goods carrier. For this purpose, the transport vehicle can be adapted, in particular, to a specific type of goods carrier and / or to a plurality of specific types of goods carriers, in particular by means of suitably designed receiving means for receiving the goods carrier.

[0018] The transport vehicle has a first goods carrier recognition device for recognizing the transported goods carrier as a specific goods carrier and / or as a goods carrier of a specific goods carrier type. The goods carrier recognition device enables the transported goods carrier to be recognized. This can, for example, make it possible to determine the mass of the load carried on the goods carrier and / or its dimensions if corresponding information about the load carried on this goods carrier is available. Alternatively and / or additionally, the goods carrier type of the transported goods carrier can be recognized using the goods carrier recognition device. This makes it possible, for example, to determine the maximum permissible mass and / or the largest possible dimensions of a load carried on a goods carrier of this goods carrier type.

[0019] The transport vehicle also has a monitoring device. This monitoring device can, in particular, be a safety controller. The monitoring device and control device are connected by a data connection. Data packets can be transmitted from the control device to the monitoring device via the data connection. The data packets are, in particular, so-called datagrams or telegrams.

[0020] The transport vehicle further comprises a second goods carrier recognition device, independent of the first goods carrier recognition device, for recognizing the transported goods carrier as a specific goods carrier and / or as a goods carrier of a specific goods carrier type. The second goods carrier recognition device initially creates redundancy in the sensor system for recognizing the goods carrier.

[0021] The object is achieved in particular in that the monitoring device is designed to carry out a comparison of the result of the detection of the transported goods carrier by the first goods carrier detection device with the result of the detection of the transported goods carrier by the second goods carrier detection device.

[0022] Within the scope of the present invention, it has been shown that such a comparison of results is suitable for ensuring sufficient reliability in the detection of the goods carrier. At the same time, comparatively inexpensive components can be used, particularly for the control device and / or the first and / or second goods carrier detection devices. This applies both to the control device and the goods carrier detection devices themselves, as well as to any accessories, such as cables for connecting these components to each other and / or to other components of the transport vehicle.

[0023] The transport vehicle is particularly designed to transmit the result of the detection of the transported goods carrier by at least one goods carrier detection device via the data connection from the control device to the monitoring device. In this context, the first goods carrier detection device can be connected in particular to the control device.

[0024] Connecting at least one, in particular the first, goods carrier detection device to the control device is expedient simply because the control device controls the drive system of the automated guided vehicle, and in this way, relevant information about the goods carrier or the type of goods carrier, and thus in particular about the load to be transported, can be transmitted directly to the control device. The connection between the first goods carrier detection device and the control device can, in particular, be a data connection.

[0025] One of the carrier recognition devices, particularly the first carrier recognition device, can be an RFID reader. RFID readers offer the advantage of being able to transmit a comparatively large amount of information when reading a corresponding RFID identifier on the carrier.

[0026] One of the goods carrier detection devices, in particular the second goods carrier detection device, can be an arrangement of reed contacts. The reed contacts can be arranged at different positions on the transport vehicle. In this context, the goods carriers can have magnets. These can, in particular, be arranged on the goods carriers in such a way that, when the goods carrier is properly picked up on the automated guided vehicle, the positions of the magnets embody information about the goods carrier and / or the goods carrier type that can be recognized by the reed contacts. In other words, by arranging reed contacts on the transport vehicle, the arrangement of the magnets on the goods carrier can be recognized, and based on the arrangement of the magnets, the transported goods carrier can be recognized as a specific goods carrier and / or as a goods carrier of a specific goods carrier type.

[0027] In this way, a robust detection method can be implemented, which has the particular advantage of being completely independent of a product carrier detection device configured as an RFID reader. In this context, the second product carrier detection device can be connected, in particular, to the monitoring device. This can mean, in particular, that the reed contacts are directly connected to corresponding signal inputs of the monitoring device. In this way, a cost-effective yet robust design of a second product carrier detection device can be implemented. This is particularly well suited for the purpose of verifying the results of a first product carrier detection device.

[0028] The transport vehicle may have a sensor arrangement for detecting obstacles within a monitoring area around the transport vehicle. The sensor arrangement may include at least one laser scanner for monitoring the monitoring area and / or a portion of the monitoring area.

[0029] In particular, the monitoring device and / or the sensor arrangement meets at least safety requirements corresponding to a Category 3 architecture and Performance Level d according to DIN EN ISO 13849-1:2016-06. Alternatively and / or additionally, the monitoring device can meet higher safety requirements, particularly with regard to Category and Performance Level according to DIN EN ISO 13849-1:2016-06, than the control device and / or the first and / or second goods carrier detection device. In this way, the highest level of functional safety can be ensured, even if some components of the transport vehicle only meet lower requirements and are therefore significantly more cost-effective.

[0030] The method for controlling a driverless transport vehicle described above provides, in particular, that data packets containing data relating to the result of the detection of the transported goods carrier by at least one goods carrier detection device are generated by the control device and transmitted to the monitoring device via the data connection. The data are, in particular, data relating to the result of the detection of the transported goods carrier by the first goods carrier detection device. With such a data transmission, the result of the goods carrier detection, which is available to the control device, can be transmitted to the monitoring device in order to enable verification of this result using the result of the detection of the transported goods carrier by the second goods carrier detection device.

[0031] The method can provide for signals from one, in particular the first, product carrier detection device to be evaluated by the control device, and signals from the other, in particular the second, product carrier detection device to be evaluated by the monitoring device. By dividing the evaluation of the signals from the product carrier detection devices in this way, an advantageous division of functions can be achieved between the product carrier detection devices and the control devices.

[0032] The method can in particular provide that the monitoring device checks the integrity of the transmitted data packets. Such a check of the integrity of the transmitted data packets can prevent errors in the data transmission from the control device to the monitoring device from resulting in errors in the operation of the electric drive system not being detected by the monitoring device. The check of the integrity of the transmitted data packets can in particular be carried out by means of a check value generated for the data packets by the control device. For this purpose, the check value can be transmitted to the monitoring device via the data connection. The check value can be transmitted as part of the respective data packet. The check value can be a checksum, for example.

[0033] The method can provide that the data packets each contain a counter value generated by the monitoring device, which is checked by the monitoring device after receipt of the respective data packet. The counter value is transmitted, in particular, to the control device via the data connection. Checking the counter value can serve, in particular, to detect errors in the operation of the control device.

[0034] The counter values ​​can be checked, in particular, by checking whether the counter value corresponds to an expected value and / or lies within an expected value range. The counter value can be generated by the monitoring device and sent to the control device, in particular at a specific time-dependent rate. In particular, if the data packets are generated at a specific time-dependent rate, the method can provide that each data packet generated and sent by the control device contains the last counter value received by the control device. An expected value range can be useful in such a method in order to avoid immediately triggering operational intervention in the event of merely momentary disturbances that, for example, lead to a minimal time delay in the transmission of a data packet by the control device.However, if, for example, a so-called "stuck at" error occurs in the control device, in which identical data packets are continuously sent to the monitoring device at constant time intervals, the monitoring device can easily detect a malfunction from the constant counter value. This constant counter value of the identical data packets would, after a short time, no longer be within the expected value range for the counter range contained in the data packet received at a specific time.

[0035] The method may provide for the evaluation of the signals generated by the sensor arrangement. The evaluation of the signals generated by the sensor arrangement may, in particular, be carried out by the monitoring device.

[0036] The method can provide that, upon detection of an error in the detection of the transported goods carrier, in particular by the monitoring device, and / or upon detection of an obstacle within the monitoring area, in particular by the monitoring device, an operational intervention is carried out, in particular by the monitoring device. In particular, the method can provide that an error in the detection of the transported goods carrier is detected if the comparison of the results of the detection of the transported goods carrier by the goods carrier detection devices, the verification of the integrity of the transmitted data packets, and / or the verification of the counter value leads to a result that does not meet the requirements for safe operation.

[0037] In this context, the method can, in particular, provide that the driverless transport vehicle is transferred into a safe operating state by the operational intervention. The safe operating state can, in particular, be an operating state in which the transport vehicle is brought to a standstill, for example, by applying one or more brakes and / or stopping the supply of electrical energy to the drive or drives of the transport vehicle, for example by means of one or more contactors. Consequently, the operational intervention can, in particular, involve applying at least one brake and / or disconnecting at least one electrical drive from its power supply.

[0038] The method can, in particular, provide for the size and / or shape of the monitoring area to be selected depending on the detected goods carrier and / or goods carrier type. The size and / or shape of the monitoring area is selected, in particular, depending on the actual or maximum possible mass and / or dimensions of the load transported by the transport vehicle, as determined by detecting the transported goods carrier. In this context, the size and / or shape of the monitoring area is selected, in particular, by the monitoring device.

[0039] Such a procedure allows for a suitable selection of the size and / or shape of the monitoring area depending on the specific goods carrier being transported. The size and / or shape are thus selected in such a way that, on the one hand, safe operation is ensured, while, on the other hand, the risk of unnecessary vehicle shutdowns due to detected obstacles is avoided. A lightly loaded or unloaded vehicle can be stopped over a much shorter distance than a heavily loaded vehicle. Therefore, a more "predictive" operating mode is required for the latter.

[0040] For example, for a lightly loaded or unloaded transport vehicle, a narrowly defined monitoring area can be selected, thus avoiding unnecessary operational interventions when the transport vehicle is stationary due to people in the detection area. Alternatively and / or additionally, a larger monitoring area can be selected for a heavily loaded transport vehicle to ensure that the transport vehicle can be brought to a standstill before a potential collision if an obstacle is detected in the monitoring area.

[0041] Further practical embodiments and advantages of the invention are described below in connection with the drawing. Fig. 1 shows a simplified representation of the components involved in detecting the transported goods carrier of an exemplary driverless transport vehicle.

[0042] In the Fig. 1 shows a highly simplified schematic representation of the components of an exemplary driverless transport vehicle involved in detecting the transported goods carrier. The driverless transport vehicle has a control device 10, by means of which the electric drive system of the transport vehicle is controlled. The further electric drive system is shown in Fig. 1 not shown for the sake of simplicity.

[0043] A first goods carrier recognition device 12 is connected to the control device 10. The first goods carrier recognition device 12 can be, for example, an RFID reader. Furthermore, the exemplary transport vehicle has a monitoring device 14. The monitoring device 14 can be, for example, a safety controller. The monitoring device 14 is connected to the control device 10 via a data connection 16.

[0044] The driverless transport vehicle further comprises a second goods carrier detection device 18. The second goods carrier detection device 18 may, for example, be an arrangement of reed contacts arranged at different positions on the transport vehicle.

[0045] The method for controlling the driverless transport vehicle provides that data packets containing data relating to the result of the recognition of the transported goods carrier by the first goods carrier recognition device 12 are generated by the control device 10 and transmitted to the monitoring device 14 via the data connection 16.

[0046] The method can provide that the data packets each contain a counter value contained by the monitoring device 14 and a check value. The check value and the counter value can be checked by the monitoring device 14. The data connection 16 can be used to transmit the counter value from the monitoring device 14 to the control device 10, before the counter value is transmitted back to the monitoring device 14 with a data packet containing data relating to the result of the detection of the transported goods carrier by the first goods carrier detection device 12.

[0047] The monitoring device 14 is designed to compare the result of the detection of the transported goods carrier by the first goods carrier detection device 12 with the result of the detection of the transported goods carrier by the second goods carrier detection device 18. This comparison can ensure a high level of operational reliability in the detection of the transported goods carrier, even if the first goods carrier detection device 12, the second goods carrier detection device 18, and the control device 10 only meet comparatively low safety requirements. In particular, the control device 10, the first goods carrier detection device 12, and / or the second goods carrier detection device 18 meet lower requirements than the monitoring device 14 with regard to the category of their architecture and / or their performance level according to DIN EN ISO 13849-1:2016-06.In particular, the monitoring device 14 can meet at least security requirements corresponding to a Category 3 architecture and / or Performance Level d according to DIN EN ISO 13849-1:2016-06. Since the results of the independent carrier detection devices 12 and 18 are only combined in the monitoring device 14, it is sufficient if only the monitoring device 14 meets the high security requirements to ensure a sufficiently high level of security overall.

[0048] The features of the invention disclosed in the present description, the drawings, and the claims may be essential, both individually and in any combination, for the realization of the invention in its various embodiments. The invention is not limited to the described embodiments. It may be varied within the scope of the claims and taking into account the knowledge of the person skilled in the art. List of reference symbols 10 Control device 12 first goods carrier detection device 14 Monitoring device 16 Data connection 18 second goods carrier detection device

Claims

[1] Driverless transport vehicle, wherein the transport vehicle has a control device (10) for controlling an electric drive system of the transport vehicle, wherein the transport vehicle is designed to transport a goods carrier, wherein the transport vehicle has a first goods carrier recognition device (12) for recognizing the transported goods carrier as a specific goods carrier and / or as a goods carrier of a specific goods carrier type, characterized by that the transport vehicle also has a monitoring device (14), wherein the monitoring device (14) and the control device (10) are connected by a data connection (16), wherein the transport vehicle has a second goods carrier recognition device (18) independent of the first goods carrier recognition device (12) for recognizing the transported goods carrier as a specific goods carrier and / or as a goods carrier of a specific goods carrier type and the monitoring device (14) is designed to compare the result of the detection of the transported goods carrier by the first goods carrier detection device (12) with the result of the detection of the transported goods carrier by the second goods carrier detection device (18). [2] Transport vehicle according to claim 1, characterized bythat the transport vehicle is designed to transmit the result of the detection of the transported goods carrier by at least one goods carrier detection device (12, 18), in particular by the first goods carrier detection device (12) via the data connection (16) from the control device (10) to the monitoring device (14). [3] Transport vehicle according to one of the preceding claims, characterized by that one of the goods carrier recognition devices (12, 18), in particular the first goods carrier recognition device (12), is an RFID reader. [4] Transport vehicle according to one of the preceding claims, characterized by that one of the goods carrier detection devices (12, 18), in particular the second goods carrier detection device (18), is an arrangement of reed contacts which are arranged at different positions of the transport vehicle. [5] Transport vehicle according to one of the preceding claims, characterized by that the transport vehicle has a sensor arrangement to detect obstacles within a monitoring area around the transport vehicle. [6] Transport vehicle according to claim 5, characterized by that the sensor arrangement comprises at least one laser scanner for monitoring the monitoring area and / or a part of the monitoring area. [7] Transport vehicle according to one of the preceding claims, characterized by that the monitoring device (14) and / or the sensor arrangement meets at least safety requirements corresponding to a Category 3 architecture and Performance Level d according to DIN EN ISO 13849-1:2016-06. [8] Method for controlling a driverless transport vehicle according to one of the preceding claims, characterized bythat data packets containing data relating to the result of the recognition of the transported goods carrier by at least one goods carrier recognition device (12, 18) are generated by the control device (10) and transmitted to the monitoring device (14) via the data connection (16). [9] Method according to claim 8, characterized by that signals from one, in particular the first, goods carrier recognition device (12) are evaluated by the control device (10) and signals from the other, in particular the second, goods carrier recognition device (18) are evaluated by the monitoring device (14). [10] Method according to claim 8 or 9, characterized bythat the monitoring device (14) checks the integrity of the transmitted data packets, in particular by means of a test value generated for each data packet by the control device (10) and transmitted to the monitoring device (14) via the data connection (16), in particular as a component of the respective data packet. [11] Method according to one of claims 8 to 10, characterized by that the data packets each contain a counter value generated by the monitoring device (14) and transmitted, in particular via the data connection (16), to the control device (10), which is checked by the monitoring device (14) after receipt of the respective data packet. [12] Method according to one of claims 8 to 11, characterized by that the signals generated by the sensor arrangement are evaluated by the monitoring device (14). [13] Method according to one of claims 8 to 12, characterized by that the transport vehicle is transferred into a safe operating state by the monitoring device (14) if the comparison of the results of the detection of the transported goods carrier by the goods carrier detection devices (12, 18), the verification of the integrity of the transmitted data packets and / or the verification of the counter value leads to a result which does not meet the requirements for safe operation and / or if an obstacle is detected within the monitoring area. [14] Method according to one of claims 8 to 13 for controlling a driverless transport vehicle according to one of claims 5 to 7, characterized by that the size and / or shape of the monitoring area, in particular by the monitoring device (14), is selected depending on the detected goods carrier and / or goods carrier type.

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