SE2051399A1 - Warehouse system and material handling vehicle - Google Patents

Abstract

Warehouse system (1) for determining the position of a material handling vehicle in a warehouse (2), wherein the system (1) comprises, a first type vehicle (3), a second type vehicle (4),wherein the first type vehicle (3) comprises an active positioning system arranged such that it with high precision can determine the position of itself (3) in the warehouse (2) in the form of a first position data, wherein the first type vehicle (3) comprises a communication device (5) that can communicate the first position data to a communication device (7) on the second type vehicle (4) through a wireless communication protocol, wherein the second type vehicle (4) comprises a control unit (12) arranged to perform a calculation based on the first position data, wherein said calculation determines a calculated position for the second type vehicle (4), based on the position data received from the first type vehicle (3), wherein the first type vehicle (3) can determine its own position with a high precision, preferably the high precision means that the determined position of the first type vehicle (3) is in the range of 0,001-1 meters of its true position, preferably 0,001-0,3 meters.

Description

WAREHOUSE SYSTEM AND MATERIAL HANDLING VEHICLE The present disclosure is related to a warehouse system according to claim 1, a method fordetermining a position of a vehicle in a warehouse according to claim 9, a computer softwareaccording to claim 14 and a computer program product according to claim 15 and a material handling vehicle according to claim 16.

BACKGROUND lt is important when performing material handling operations to know the position of a vehicle inlogistic centre. The increased requirements for efficiency demands that planning for materialhandling such as order picking operations is precisely performed. ln order to control and plan suchoperations the position of each vehicle in a warehouse is of crucial importance. There are differentways to achieve the needed positioning known. For example it is known from the documentUS201715416017 A1 to use a positioning system, including a plurality of anchor stations eachconfigured to transmit a radio frequency signal to a mobile station. This system uses anchor stations that are used as beacons. lt is also known with modern vehicles in the warehouse that can be AGV-automated guided vehicles,that manoeuvres in a warehouse situation by means of an inbuilt navigation system that candetermine the position of the AGV very precisely, within millimetres of the true position. Often the AGV's uses both passive and active sensors, such as laser, radar or ultrasound detectors.

SHORT DESCRIPTION OF THE INVENTION The above described known systems for positioning have the disadvantage of being complex andinvolving large investments in order to function. lt has been recently become interesting also toposition determine vehicles in a warehouse that is simple in their design and not so advanced as the above discussed positioning system and vehicles. lt is thus proposed a warehouse system for determining the position of a material handling vehicle ina warehouse. The system comprises, a first type vehicle and a second type vehicle. The first typevehicle comprises a active positioning system. The active positioning system is arranged such that itwith high precision can determine the position of the first type vehicle in the warehouse. Theposition is given in the form of a first position data. The first type vehicle comprises a communicationdevice. This communication device can communicate the first position data to a communicationdevice on the second type vehicle. The communication is performed through a wirelesscommunication protocol. The second type vehicle comprises a control unit which is arranged toperform a calculation based on the first position data. The calculation determines a calculated position for the second type vehicle. The calculation is based on the position data received from the first type vehicle. The first type vehicle can determine its own position with a high precision. lt ispreferred that the high precision means that the determined position of the first type vehicle is in the range of 0,001-1 meters of its true position, preferably 0,001-0,3 meters.

The advantage of this system is that a simple vehicle can be position determine in a warehouse in asimple and sufficiently efficient manner. The required position will not be sufficient for automaticguided control, but will help managing a warehouse in an unexpected and efficient manner. The positioning will of course be improved if more position data is received at each moment in time.

According to a further aspect of the invention there is disclosed a warehouse system where thecommunication devices of the warehouse system is arranged to communicate by a Bluetoothcommunication protocol. Or, the communication devices of the warehouse system can be arrangedto communicate by a ultra wide band communication protocol. Or wherein the communicationdevices uses a WLAN protocol such as any protocol under IEEE 802. Or wherein the communication devices uses a cellular protocol such as edge, 2G, 3G, 4G, 5G.

The advantage of using a Bluetooth communication protocol is among other things, that standardcomponents are easy to find. There is also an advantage in terms of battery management. Also theshort range of Bluetooth allows for more simple management in a warehouse where many first typevehicles can operate at the same time. Thus only vehicles which are closest to the second typevehicle will be able to send position data. By using an ultra-wide band protocol the precision of theposition determination will improve over a Bluetooth connection. By using an Edge, G2, G3, G4 or G5cellular connection it is possible to with ease provide a position in particular both inside and outside a warehouse building.

According to a further aspect of the invention there is disclosed a warehouse system where thesecond type vehicle is arranged for manual operation. Thus the second type vehicle comprises amanual steering device and a manual speed control device. lt is preferred that said second type vehicle comprises a load carrier. The load carrier is preferred to be a pair of forks.

The advantage of positioning a vehicle that is arranged for manual operation incorporate in thewarehouse system is that the positioning will not need to be very precise. The position only need tobe approximately determined as an operator can correct any difference between determined position and the true position.

According to a further aspect of the invention there is disclosed a warehouse system wherein thesecond type vehicle also can receive a further position data. This further position data can be received from a fixed positioning device. The second type vehicle is arranged such that it can use the further position data together with the first position data for improving the calculation of the position of the second type vehicle itself.

By receiving a further position data it is possible to further determine the position for the second type vehicle more precisely, in a triangular operation.

According to a further aspect of the invention there is disclosed a warehouse system wherein theactive positioning system of the first type vehicle comprises at least one sensor. The sensor candetermine the distance from the vehicle to a fixed object in the warehouse. lt is preferred that distances can be determined to several fixed objects in the warehouse.

The advantage of the features of providing the active positioning system of the first type vehicle witha sensor is a confirmation of the very precise determination that the first type vehicle is arranged to be perform.

According to a further aspect of the invention there is disclosed a wherein the sensor compriseseither of, a radar sensor, and/or a laser sensor, and/or an ultra sound device, and/or a visual sensor such as at a camera or a 3D camera.

The advantage of a radar sensor is that it gives reliable data even under changed conditions, i.e. lineof sight etc. A laser sensor gives very exact determination of the position of objects detected. Ultrasound devices are very cost effective. Using a visual sensor allows for a reasonable good detection for positioning.

According to a further aspect of the invention there is disclosed a warehouse system, wherein thewarehouse system further comprises a third vehicle. The third vehicle comprises an activepositioning system arranged such that it with high precision can determine the position of itself inthe warehouse. The position gives a second position data. The second type vehicle is arranged suchthat it can receive the second position data that correspond to the position for the third vehicle. Thesecond type vehicle can use the second position data together with the first position data in order to determine a position for the second type vehicle itself.

When a third vehicle becomes involved there will be a possibility to make a comparison and a triangulation operation to determine the position in a more precise manner.

According to a further aspect of the invention there is disclosed a warehouse system, wherein thecalculated position for the second type vehicle is in the range of 0,1 meters to 10 meters. lt is preferred that the position is preferably 0,5-8 meters, from the true position of the second type vehicle , such that the position is useful for determining in what section of a warehouse the second type vehicle is positioned.

The advantage of having a range in 0,1-10 meters is that it is not so exact. This seems at first to be acontradiction as the object of the disclosure is to determine a position. But by not going to precise itbecomes cost effective and possible to implement the development into low budget material handling vehicles that in general is not position determined.

According to a further aspect of the invention there is disclosed a method for determining a positionof a vehicle in a warehouse comprising a step I of providing a first type vehicle comprising an activepositioning system arranged such that it with high precision can determine the position of the firsttype vehicle, wherein the first type vehicle is arranged to be able to communicate with a second typevehicle. The method also comprises a step ll of providing a second type vehicle comprising a controlunit that can receive first position data from the first type vehicle. The method also comprise thestep ||| of sending a first position data from the first type vehicle to the second type vehicle. Themethod also comprise a step IV of using the control unit for calculating the position of the second type vehicle based on the first position data received from the first type vehicle.

With the method it is achieved a sufficiently good positioning using first type vehicles with alreadyinstalled active positioning systems without having the same equipment on the second type vehicle.This will be cost effective and allow for further vehicles in a warehouse to have a positiondetermining ability. This in turn will increase the efficiency of the overall material handling in the warehouse.

The method is implementable into a material handling vehicle that has a programmable control unit in a simple manner with a mere modification with a transceiver for receiving the position data.

According to a further aspect of the invention there is disclosed a method according to the abovecomprising the further step la of providing a third vehicle comprising an active positioning systemarranged such that it with high precision can determine the position of the third vehicle, wherein thethird vehicle is arranged to be able to communicate with a second type vehicle. The method alsocomprise the stop ||a to arrange the second type vehicle such that it can receive a second positiondata from the third vehicle. The method also comprise a step |||a of sending a second position datafrom the third vehicle to the second type vehicle. The method also comprise a step |Va of using thecontrol unit for calculating a position of the second type vehicle based on the first calculated positionand the second position data received from the third vehicle , or by using the first position data andthe second position data in a combined calculation of position. lt is preferred that the third vehicle is a second first type vehicle By adding further vehicles with navigation equipment installed the position determining for the second type vehicle is improved. This is despite the fact that a more complex calculation is necessary.

According to a further aspect of the invention there is disclosed a method according to the abovecomprising a step lb of providing a fixed position device in the warehouse that is able tocommunicate with the second type vehicle. The method also comprise the step ||b to arrange thesecond type vehicle such that it can receive a position data from the fixed positioning device. Themethod also comprise the step of |||b sending a position data from the fixed position device to thesecond type vehicle. The method also comprise the step IVb of using the control unit for calculating aposition of the second type vehicle based on the first position data and/or the second position data and/or the third position data.

The fixed positioning devices can be used as a complement to the moving first type vehicles and/orthird vehicles. The fixed positioning devices requires hardware installation in the warehouse,however they can have a very precisely determined position and thus improves the determination of the position of the second type vehicle.

According to a further aspect of the invention there is disclosed a method according to the aboveaspects wherein, any position data when sent to the second type vehicle is provided with a first timestamp. The control unit of the second type vehicle is able to compare the first time stamp with asecond time stamp determined by the second type vehicle. And the method involves to compare thetime difference between the first time stamp the second time stamp. Thereby the control unit cancalculate the distance to the vehicle and/or fixed position device that sent the position data to the second type vehicle and thereby determine a position for the second type vehicle.

This aspect gives a precise alternative on how the specific calculation is performed in order to calculate the position of the second type vehicle.

According to a further aspect of the invention there is disclosed method wherein the detected signalstrength of the signal carrying the position data is used for determining a distance between the first type vehicle, and/or a third vehicle and/or a fixed positioning device.

The above aspect of the method provides for a simple determination of the distance between the second d vehicle and the vehicle or fixed position device sending out the position data.

According to a further aspect of the invention there is disclosed a software that when executed on acontrol unit of a material handling vehicle, is able to perform the method according to any of the aspects above.

The advantage of this is that there is an easy implementation of the discussed method. And any material handling vehicle having a programmable control unit can be modified with the method.

According to a further aspect of the invention there is disclosed a computer program productcomprising a computer software to the above aspect, that when stored on a computer readablemedium can be implemented into a material handling vehicle such that it will be able to execute the method according to any of the aspects above.

The computer program product can be easily downloaded or delivered on a hardware device for easy distribution of the modification according to the software and method.

According to a further aspect of the invention there is disclosed a material handling vehicle,comprising a control unit comprising, a software according to the aspect above, a communicationunit able to receive position data, wherein the vehicle is able to determine its own position by receiving position data from at least one other vehicle and/or a fixed position device.

The second type vehicle of this aspect will be cost effective to upgrade or deliver with the ability of sufficiently accurate position determining.

LIST OF DRAWINGS Figure 1 discloses a warehouse system and a material handling vehicle according to the disclosure.Figure 2 discloses a flowchart for a method according to the disclosure.

DETAILED DESCRIPTION The present disclosure is related to warehouses. The warehouse environment is becoming more andmore complex with many goods handled in short periods of time. The warehouse can be anywarehouse, it can also be a store, as a supermarket, that does not actually have a storage section butinstead stores the goods inside the store itself. lt should also be understood that a warehouse is notintended to be limited to a single building, it can be a complex group of buildings that togetherconstitutes a warehouse according to the present disclosure. Thus it should be understood that awarehouse can be a logistic centre or the like. lt must also be understood that the present disclosureis not necessarily only involving indoor operation. lt can be a combination of indoor operation andoutdoor operation. lt can also be an outdoor operation. lf it is an outdoor operation it is requiredthat the support for the material handling vehicles involved is sufficient for allowing them to operate.lt is not considered possible for example to involve areas of crops and farming in the discloser as thiswould require considerable modification of the vehicles. Also material handling does not mean personal transport.

The present disclosure is related to warehouse 2 with a warehouse system 1, Figure 1. Thewarehouse system 1 of the present disclosure must involve at least one first 3 and one second typevehicle 4 with certain properties. All features disclosed in Figure 1 is not to be seen as limiting the present disclosure. Thus for example the racks 8 are not part of the scope.

The disclosure is related to the position of the second type vehicle 4 and the determination of thisposition. For sake of simple disclosure the position is disclosed as the centre point 15 of a housing ofthe second type vehicle 4. However it is of course possible to choice another point on the secondtype vehicle 4 as reference point for determining the position. Thus in the following a position of thesecond type vehicle 4 may be construed as the position of the centre point 15. Also for the first typevehicle 3 position is related to a centre point of this vehicle. There should also be understood thatthere is a difference between the position and the calculated position. The calculated position is anapproximation of the position of the second type vehicle 4. That is the centre point 15 of the secondtype vehicle is not necessarily positioned in the warehouse 2 at the exact position that the calculation leads to.

The vehicles that is discussed in the present disclosure are material handling vehicles. However thisdoes not imply that they are of exactly the same type. ln general the first type vehicle 3 is to beconsidered as a more advanced vehicle than the second type vehicle in terms of navigation ability.The first type vehicle 3 is arranged with an active positioning system. That is, it is arranged such thatit can on its own with high precision determine its position. This is performed by a complex system ofat least one sensor 10 and may be combined with an inbuilt map, for a control unit on the first typevehicle 3 to use together with the input received from the sensor 10. The first type vehicle 3 may bean AGV, that is an Automated Guided Vehicle. This means that it is intended to be operated in anautomated way in the warehouse system 1. This also means that it is not intended to be manuallyoperated by hardware controls that is mounted on the first type vehicle 3. |nstead the vehicle isintended to be able to operate in a material handling operation without specific guiding or control atevery moment. This means that the firs vehicle might be given from a master controlunit/server/operator at distance, coordinates in a warehouse. At receipt of these coordinates thefirst type vehicle may then without further instructions travel to the given coordinate in thewarehouse and continuously monitor its own position. The first type vehicle may also includesystems for obstacle avoidance and obstacle following such that it can safely manoeuvre in thewarehouse. The first type vehicle in addition to this has communication device 5. This device isarranged for communication with other vehicles, such as the second type vehicle 4. Thecommunication device 5 is preferred to be a transceiver that both can receive and emit wireless information.

The first type vehicle active positioning system is thus sufficiently accurate such that it can determinethe position of the first type vehicle at any moment. With high precision is meant that it is sufficientfor performing an independent warehouse material handling operation. This requires that the trueposition for the first type vehicle and the determined position for the first type vehicle does notdiffer by more than some centimetres, preferably by some millimetres. ln some occasions adifference up to 1 meter can be allowed, but preferably this is much more accurate, even down to 1 millimetre.

The first type vehicle is thus by means of its active positioning system that comprises at least thesensor 10 and a control unit 21, able to determine its position precisely and the send this position ineither a broadcast output or as an addressed output so that it can be received of a second typevehicle 4 within range. A broadcast message means that the first type vehicle continuously sends outa position data that can be received by any second type vehicle 4 within range. The first type vehicle3 thus uses a communication device 5 that can either transmit broadcast or addressed information.An addressed output of position data is requiring other operation of the communication such as ahand shake operation between the two vehicles that is in communication. This is a more complexoperation but can be advantageous in terms of battery management and energy saving. The firsttype vehicle 3 can also use the sensor 10 or a further sensor not disclosed when manoeuvring in theenvironment and detect objects 8 around itself. The objects can be fixed objects 8 such as racks, but also human operators and other vehicles in the environment.

The first position data preferably comprises a very exact position of the first type vehicle 3. This means for example for the disclosure the centre point 14 of the first type vehicle 3.

The fist position data can also be stamped with a time mark. The time stamp can then be transmitted with the position data to be received by the second type vehicle 4.

The second type vehicle 4 differs from the first type vehicle in that it does not comprise a realpositioning system that allows the second type vehicle to determine its position by itself. ln order forthe second type vehicle 4 to navigate it requires external input, in particular from a first type vehicle3. However the first type vehicle 3 can navigate without any input from the second type vehicle 4. lngeneral it could have sensors and equipment that would be added for safety reasons. The secondtype vehicle 4 does comprise a control unit 12. The second type vehicle 4 also comprises acommunication device 7 that can receive position data, in particular from the first type vehicle, butof course from further vehicles or fixed position devices. The control unit 12 then can determine the position for the second type vehicle by using the position data received. ln its simplest manner the position is determined by determining that a position data is received and a calculated position for the second type vehicle 4 is set to same value as the position for the first type vehicle 3.

The calculated position of the second type vehicle 4 can then be sent to a central server/control unitor the like of a warehouse management central. Such that a warehouse management system candetermine where the second type vehicle 4 is currently positioned. lt must be understood that if theposition from only one source being the first type vehicle is received the calculated position is farfrom exact. An area 20 in Figure 1 symbolizes that the position is not so precise if very few positiondata is received. However for the management of a large warehouse 2 there can be sufficient inorder to manage of the second type vehicle 4 should pursue for example an order picking operationin order to be efficient. The calculation made by the control unit 12 is preferred to be performed bymeans of a software that has been stored and executed on the control unit 12. The calculatedposition can thus for example be sufficient if the true position compared with the calculated positiondiffers with 10 meters. But it is more preferred if the calculated position is determined in the range of 0,5-8 meters difference.

The second type vehicle 4 can be arranged for manual operation. lt is preferred that the second typevehicle 4 is arranged for manual operation, as an automated second type vehicle 4 could havetrouble to manoeuvre with sufficient precision to fulfil its material handling operation and also togive challenges in terms of safety. With manual operation means that an human operator controlsthe vehicle 4. This can for example be made by a manual steering device 9. lt is also possible to havea manual speed control device 19. The manual steering device 9 can be a tiller arm, a steering wheel,a joystick, or like. The manual speed control device can be command device that can be turned inone direction for travel in direction of a load carrier and in the other direction can be turned fortravel in the opposite direction. Manual operation can also be performed by means of a remotecontrol device, such as a remote control, a computer with remote control capability. The remotecontrol can be a wireless remote control or a wired remote control. The second type vehicle 4 mayalso comprise a load carrier 13. The load carrier may be a pair of forks. The second type vehicle canbe a floor conveyor, a tiller arm truck, a reach truck a narrow aisle truck, fork-lift truck, a counterbalance truck, a stacker truck, a low lifting truck or even a pallet truck without propulsion. Thesecond type vehicle need not be an electrically powered truck. lt can have a combustion enginedriven by diesel, gasoline, LPGA, or other fuels. However it is in general preferred that the secondtype vehicle (and the first type vehicle) is an electrically powered vehicle. Thus requiring an energy source and possibility of charging at times when performing the material handling operations.

The communication devices 5 and 7 can communicate by means of a Bluetoothfi' protocol is used thiswould be used according to any of the suitable standards for this protocol. The use of Bluetooth®gives good battery management and is versatile. The use of this technique is mainly addressed byusing the strength of the signal that is received by the second type vehicle 4. The signal strengthreceived will correspond more or less to a distance 16 between the first type vehicle 3 and thesecond type vehicle 4. The general formula is that the strength of the signal will be a function of the inversed distance in square. lt is also thinkable to use an ultra-wide band communication protocol, UWB. The use of UWB willimprove the possibility to determine the position of the second type vehicle 4. The UWB in particularallows for sending more position data more often than for example a Bluetooth protocol. The UWB can be any standard protocol for this type of communication that is wireless. lt is also possible to use other protocols or systems such as a Wire Less Lan system. The wireless Lansystems can be arranged according to industry standards such as described in IEEE 802. lt is also possible to use cellular protocols such as GSM, 2G, 3G, 4G or 5G, or Edge for example. ln the warehouse system there can also be introduced a fixed positioned device 6. ln general in theform of a beacon that broadcasts the position of the beacon itself. ln order for a good functionalitythe position of the fixed position device needs to be predetermined by a measurement operation.Thus in general terms it is not possible to move a fixed position device 6 as I then will send outincorrect information. Broadcast beacon sending is in general the normal functionality however it ispossible to consider an addressed functionality for sending the position data of the fixed position device 6.

The second type vehicle 4 having received for example a position data from a first type vehicle 3 canthe also at the same time receive a position data from a fixed positioning device 6. The calculation ofthe position of the second type vehicle 4 can thus be improved. One way of improving the positionwould be to determine the distance 16 from the second type vehicle 4 to the first type vehicle 3, andat the same time determine the distance 18 from the fixed positioning device 6 to the second typevehicle 4. Once these distances have been determined the control unit 12 of the second type vehicle4 can perform a triangulation approximation for improving the calculated position of the second type vehicle 4.

The sensor 10 of the first type vehicle 3 can be a radar sensor. The sensor 10 can also be a lasersensor. The sensor 10 can also be an ultra sound device. The sensor 10 can also be a visual sensor such as a camera or a 3D camera. The first type vehicle preferably has several sensors used in 11 combination for example both radar and a laser sensor. A visual sensor can be advantageous if an operator at distance needs to verify the surroundings of the first type vehicle 3.

As part of the disclosure it is also disclosed a third vehicle 11. The third vehicle 11 is in general furthervehicle ,i.e. a further second vehicle of the same type as the first type vehicle 3. Thus, the thirdvehicle 11 is fully interchangeable with the first type vehicle 11. The second type vehicle 4 is arranged such that it can receive position data from the third vehicle 11, and at the same timereceive a position data from a first type vehicle 3. A calculation of the position of the second typevehicle 4 is thus determined with more than one position data received from vehicles in thewarehouse system 1. The precision of the calculated position can thus be further improved. lndetermining the position of the second type vehicle 4, the distance 16 to both the first type vehicle 3and the distance 17 to the third vehicle 11 the calculation is made in a triangulation operation. Thustwo vehicles 3, 11 that are able to determine their position in a high precision way are thus used for the calculation of the position of the second type vehicle 4.

The disclosure is also related to a method for determining a position of a vehicle in a warehouse comprising four steps |-|V.

The first step I being to provide a first type vehicle 3. The first type vehicle 3 should comprise anactive positioning system. This positioning system should be arranged such that it with high precisioncan determine the position of the first type vehicle 3. The first type vehicle 3 is also arranged to be able to communicate with a second type vehicle 4. ln a second step ll there is provided a second type vehicle 4 The second type vehicle comprises a control unit 12. The control unit 12 can receive first position data from the first type vehicle 3. ln a third step ||| there is a sending a first position data from the first type vehicle 3 to the second type vehicle 4. ln the fourth step IV the control unit 12 is used for calculating the position of the second type vehicle 4 based on the first position data received from the first type vehicle 3.

The method can further be modified by steps |a-|Va in addition to steps |-|V already discussed. A stepla is added wherein it being a providing a third vehicle 11 comprising an active positioning systemarranged such that it with high precision can determine the position of the third vehicle 11, whereinthe third vehicle 11 is arranged to be able to communicate with a second type vehicle 4. The methodthen further is added with a step ||a of arranging the second type vehicle 4 such that it can receive asecond position data from the third vehicle 11. ln an ensuing added step |||a there is a sending a second position data from the third vehicle 11 to the second type vehicle 4. ln an ensuing added step 12 IVa there is a using of the control unit 12 for calculating a position of the second type vehicle 4 basedon the first calculated position and the second position data received from the third vehicle 11, or byusing the first position data and the second position data in a combined calculation of position. ltshould be understood that the steps |a-|va meshes in with the previous steps |-|V for a combinedmethod, such that both first type and the third vehicle 3, 11 are used to determine the calculated position of the fourth vehicle 4.

The method can be modified by the steps |b-|Vb. The method adds the step lb in providing a fixedposition device 6 in the warehouse 2 that is able to communicate with the second type vehicle 4. Themethod adds the step ||b that arranges the second type vehicle 4 such that it can receive a thirdposition data from the fixed positioning device 6. The method adds the step |||b of sending a thirdposition data from the fixed position device 6 to the second type vehicle 4. The method adds the step|Vb using the control unit 12 for calculating a position of the second type vehicle 4 based on the firstposition data and/or the second position data and/or the third position data. That the first, secondand third position data can be interchanged. Such that for example only the third position data isused in the method with original method steps |-|V same with second position data. Also it should be understood that all steps |-|V, |a-|Va, |b-|Vb can all be used together.

As a further modification of the method any position data when sent to the second type vehicle 4 canbe provided with a first time stamp t1, wherein the control unit 12 of the second type vehicle 4 isable to compare the first time stamp t1 with a second time stamp t2 determined by the second typevehicle 4. And also compare the time difference between the first time stamp t1 and the second timestamp t2. This time difference t1-t2 can then be used to calculate the distance 16, 17, 18 to thevehicle 3, 11, i.e. the first type vehicle 3 and/or third vehicle 11 and/or fixed position device 6 thatsent the position data to the second type vehicle 4 and thereby determine a position for the secondtype vehicle 4. lt must be understood that the above implies that the control unit 12 comprises atime measuring device. lt is also to be understood that the first type and third vehicles 3, 11 alsocomprises time measuring devices. lt should also be understood that there might be a need tosynchronize the different time measuring devices in order for the calculation of the position to be sufficiently precise. lt is also a possibility to use a method where the detected signal strength of the signal carrying theposition data is used for determining a distance 16, 17, 18 between the first type vehicle 3, and/or athird vehicle 11 and/or a fixed positioning device 6. This means that a lower signal will mean a longer distance is determined. 13 The disclosure is also related to a computer software that when executed on a control unit 12 of a material handling vehicle 4, is able to perform the method according to the above.

The disclosure is also related to a computer program product comprising a computer softwareaccording to claim 13, that when stored on a computer readable medium can be implemented into a material handling vehicle such that it will be able to execute the method according to the above.

The disclosure is also related to a material handling vehicle 4, comprising a control unit 12comprising, a software according to the above, a communication unit 7 able to receive position data,and the vehicle 4 is able to determine its own position by receiving position data from at least oneother vehicle 3, 11 and/or a fixed position device 6. This means that an older material handlingvehicle that was produced long time ago can be modified with a new software and a communication device in order to achieve the methods and warehouse system 1 as described above. ln the above there is discussed three vehicles. lt should be understood that there can be many morevehicles in terms of the disclosure. The second type vehicle can communicate with any number ofvehicles that provide position data, thus considerably decreasing the difference between the true position of the second type vehicle 4 and the calculated position.

Claims (16)

1. Warehouse system (1) for determining the position of a material handling vehicle in a warehouse(2), wherein the system (1) comprises: a first type vehicle (3), a second type vehicle (4), wherein the first type vehicle (3) comprises an active positioning system arranged such that it withhigh precision can determine the position of the first type vehicle (3) in the warehouse (2) in theform of a first position data, characterized in that, the first type vehicle (3) comprises a communication device (5) that can communicate the firstposition data to a communication device (7) on the second type vehicle (4) through a wirelesscommunication protocol, wherein the second type vehicle (4) comprises a control unit (12) arrangedto perform a calculation based on the first position data, wherein said calculation determines acalculated position for the second type vehicle (4), based on the position data received from the firsttype vehicle (3), wherein the first type vehicle (3) can determine its own position with a highprecision, preferably the high precision means that the determined position of the first type vehicle (3) is in the range of 0,001-1 meters of its true position, preferably 0,001-0,3 meters.

2.Warehouse system (1) according to any of the claims above, wherein the communication devices(5,7) of the warehouse system (1) is arranged to communicate by a Bluetooth communicationprotocol, or wherein the communication devices (5, 7) is arranged to communicate by a ultra wideband communication protocol, or wherein the communication devices uses a WLAN protocol such asany protocol under IEEE 802, or wherein the communication devices uses a cellular protocol such as edge, 2G, 3G, 4G, 5G.

3. Warehouse system (1) according to any of the claims above, wherein the second type vehicle (4) isarranged for manual operation by comprising a manual steering device (9) and a manual speedcontrol device (19), preferably said second type vehicle comprises a load carrier (13), even more preferred said load carrier (13) is a pair of forks.

4. Warehouse system (1) according to any of the claims above, wherein the second type vehicle (4)also can receive a further position data from a fixed positioning device (6), and wherein the secondtype vehicle (4) is arranged such that it can use the further position data together with the first position data for improving the calculation of the position of the second type vehicle itself (4).

5. Warehouse system (1) according to any of the claims above, wherein the active positioning system of the first type vehicle (3) comprises at least one sensor (10) that can determine the distance from the vehicle (3) to a fixed object (8) in the warehouse (2), preferably to several fixed objects (8) in the warehouse (2).

6. Warehouse system (1) according to claim 5, wherein the sensor (10) comprises either of, a radarsensor, and/or a laser sensor, and/or an ultra sound device, and/or a visual sensor such as at a camera or a 3D camera.

7. Warehouse system (1) according to any of the claims above, wherein the warehouse systemfurther comprises a third vehicle (11), wherein the third vehicle comprises an active positioningsystem arranged such that it with high precision can determine the position of itself (11) in thewarehouse (2) in the form of a second position data, and wherein the second type vehicle (4) isarranged such that it can receive the second position data that correspond to the position for thethird vehicle (11), where in the second type vehicle (4) can use the second position data together with the first position data in order to determine a position for the second type vehicle (4) itself.

8. Warehouse system (1) according to any of the claims above, wherein the calculated position forthe second type vehicle (4) is in the range of 0,1 meters to 10 meters, preferably 0,5-8 meters, fromthe true position of the second type vehicle (4), such that the position is useful for determining in what section of a warehouse the second type vehicle is positioned.

9. Method for determining a position of a vehicle in a warehouse comprising the steps of: 0 (I) providing a first type vehicle (3) comprising an active positioning system arranged suchthat it with high precision can determine the position of the first type vehicle (3), whereinthe first type vehicle (3) is arranged to be able to communicate with a second type vehicle(4), 0 (ll) providing a second type vehicle (4) comprising a control unit (12) that can receive firstposition data from the first type vehicle (3), 0 (|||) sending a first position data from the first type vehicle (3) to the second type vehicle (4), 0 (IV) using the control unit (12) for calculating the position of the second type vehicle (4) based on the first position data received from the first type vehicle (3).

10. Method according to claim 9 comprising the steps of: 0 (la) providing a third vehicle comprising an active positioning system arranged such that itwith high precision can determine the position of the third vehicle (11), wherein the thirdvehicle (11) is arranged to be able to communicate with a second type vehicle (4), 0 (||a) arrange the second type vehicle (4) such that it can receive a second position data from the third vehicle (11),0 (llla) sending a second position data from the third vehicle (11) to the second type vehicle(4), 0 (lVa) using the control unit (12) for calculating a position of the second type vehicle (4) basedon the first calculated position and the second position data received from the third vehicle(11), or by using the first position data and the second position data in a combined calculation of position, preferably the third vehicle is a second first type vehicle.

11. Method according to claim 9 or 10 comprising the steps of: 0 (lb) providing a fixed position device (6) in the warehouse (2) that is able to communicatewith the second type vehicle (4), 0 (llb) arrange the second type vehicle (4) such that it can receive a position data from thefixed positioning device (6), 0 (lllb) sending a position data from the fixed position device (6) to the second type vehicle (4), 0 (lVb) using the control unit (12) for calculating a position of the second type vehicle (4) based on the first position data and/or the second position data and/or the third position data.

12. Method according to any of the claims 9-11 wherein, any position data when sent to the secondtype vehicle (4) is provided with a first time stamp (t1), wherein the control unit (12) of the secondtype vehicle (4) is able to compare the first time stamp (t1) with a second time stamp (t2)determined by the second type vehicle (4) and compare the time difference between the first timestamp (t1) and the second time stamp (t2), and thereby calculate the distance (16, 17, 18) to thevehicle (3, 11) and/or fixed position device (6) that sent the position data to the second type vehicle (4) and thereby determine a position for the second type vehicle (4).

13. Method according to any of the claims 9-12, wherein the detected signal strength of the signalcarrying the position data is used for determining a distance (16, 17, 18) between the first type vehicle (3), and/or a third vehicle (11) and/or a fixed positioning device (6).

14. Computer software that when executed on a control unit (12) of a material handling vehicle (4), is able to perform the method according to any of the claims 9-

15. Computer program product comprising a computer software according to claim 14, that whenstored on a computer readable medium can be implemented into a material handling vehicle such that it will be able to execute the method according to any of the claims 9-13 above.

16. Material handling vehicle (4), comprising a control unit (12) comprising: a software according to claim 14,a communication unit (7) able to receive position data,wherein the vehicle (4) is able to determine its own position by receiving position data from at least one other vehicle (3, 11) and/or a fixed position device (6).