EP3747827A1

EP3747827A1 - Material handling vehicle

Info

Publication number: EP3747827A1
Application number: EP19178211.9A
Authority: EP
Inventors: Gabriel RINGIUS; Henrik Larsson
Original assignee: Toyota Material Handling Manufacturing Sweden AB
Current assignee: Toyota Material Handling Manufacturing Sweden AB
Priority date: 2019-06-04
Filing date: 2019-06-04
Publication date: 2020-12-09

Abstract

Material handling vehicle (1), comprising, a load carrier (2), preferably a pair of forks, a drive motor (3), a hydraulic motor (4) powering an hydraulic pump (5), a hydraulic system (6) pressurized by said pump, an energy source (23) for powering the vehicle and its motors, a control unit (7), wherein said load carrier (2) is arranged by means of the hydraulic system can lift a load, the material handling vehicle (1) have a longitudinal direction (8) and a transversal direction (16), a first side (9) extending parallel with the longitudinal direction, a second side (10) extending in parallel with the longitudinal direction, a back side (11) transversal to the longitudinal direction, a front side (17) transversal to the longitudinal direction, wherein the material handling vehicle (1) comprises detecting devices (18, 19, 20, 21; 24, 25) on the first side (9) and the second side (10), wherein said detecting devices (18, 19, 20, 21; 24, 25) are arranged such that they can detect and follow an aisle (11) in a warehouse, wherein the detecting devices (18, 19, 20, 21; 24, 25) are arranged such that they can detect a wall-ribbon (12, 13) that extend in parallel with a warehouse rack (14, 15), and detect the distance (32, 33) to said wall-ribbon (12, 13) from at least one of the first side (9) or the second side (10) to the wall-ribbon (12, 13) .The disclosure also related to a warehouse rack, a warehouse system, a method for operating a material handling vehicle, a computer software and a computer program product.

Description

FIELD OF THE INVENTION

The present invention is related to a material handling vehicle according to claim 1 .The invention is also related to a warehouse rack of claim 10, a warehouse system of claim 11, a method for operating a material handling vehicle of claims 12, a computer software of claim 13, a computer program product according to claim 14 and a method for arranging a warehouse according to claim 15.

BACKGROUND

In material handling in narrow aisles of warehouses it is commonly known to control the steering of material handling vehicles. The reason being that the warehouse ground space needs to be effectively used and thus the aisles is arranged to be very narrow. As a consequence the warehouse racks in the warehouses have become positioned so close to each other that manual control of the material handling vehicles would be dangerous for the operators, and also for the goods and material handled. The control of steering while in the aisle is known by different aisle following techniques. On such common method is to mill down wires into the floor of the warehouse which the material handling vehicles can detect and follow in an automatic manner. Aisle following can also be performed in a mechanical way by using a rail on the sides of the aisle, that side rolls on the material handling vehicle can follow. These known technologies require quite extensive modification of the warehouse itself. It is a cumbersome operation to mill down wires in the floors. The rails needed for mechanical control of the vehicle sideways in the aisle are difficult to install due to strength required of the components. Also the rails require a lot of maintenance as the guided material handling vehicles tend to bruise the rails after a certain time. Also the rails of a warehouse for guiding a very narrow aisle warehouse truck is very solid and have high strength. In general they are made from steel that can be 5-20 mm thick so that the material handling vehicle can enter into the rail without damaging the rail. The rail is in general bolted to the concrete floor at a plurality of positions along the rail. Thus the installation of the rail is cumbersome and amounts to a time and cost consuming process.
Document US 2011/0153139 A1 discloses an optoelectronic sensor to be used with a vehicle in a storage and logistic centre. The sensor allows for increased availability by applying intelligent protected field adaption to the movement and position of the vehicle, in such a way that the front of the vehicle is monitored dynamically into the path of the vehicle. The main reason being to prevent unnecessary shut downs due to path borders coming into the field of detection of the vehicle. The optoelectronic sensor requires very complex algorithms to function properly.

SHORT DESCRIPTION OF THE INVENTION

It is therefore an object of the present invention to present a material handling vehicle. The material handling comprising a load carrier, preferably a pair of forks, a drive motor, a hydraulic motor powering an hydraulic pump, a hydraulic system pressurized by said pump and an energy source for powering the vehicle and its motors. The material handling vehicle further comprises a control unit. The load carrier is arranged by means of the hydraulic system to lift a load. The material handling vehicle have a longitudinal direction and a transversal direction. The material handling vehicle has a first side extending parallel with the longitudinal direction. The material handling vehicle has a second side extending in parallel with the longitudinal direction. The material handling vehicle also has a back side transversal to the longitudinal direction and a front side transversal to the longitudinal direction. Wherein the material handling vehicle comprises detecting devices on the first side and the second side. The detecting devices are arranged such that they are able to detect a wall-ribbon. The wall-ribbon extend in parallel with a warehouse rack. The detecting devices are arrange to be able to detect a distance from at least one of the first side or the second side to the wall-ribbon.
The advantage of the vehicle is that the modification of the material handling vehicle is cost effective and unexpectedly effective for achieving narrow aisle function ability. A material handling vehicle can be modified into having the capability to be used in narrow aisles in a warehouse. In general narrow aisles vehicles or very narrow aisle vehicles are very specialised. By the disclosure above it is made possible to achieve a material handling vehicle that is easier to modify into narrow aisle capability. It is possible to use a material handling vehicle which is guided in the aisle by means of rolls with vertical rotation axis that engage rails to the side, however this means that the aisle itself need extensive adaptation with very strong rails on the sides at the base of the warehouse racks. This is due to the fact that the rails need to be able to keep the vehicle in the aisle for avoid running into the warehouse racks. Thus if a material handling vehicle is arranged according to the above it is possible for the material handling to follow a much simpler wall-ribbon instead of a rail, and the wall-ribbon need not to be able to withstand the moving mass of a material handling vehicle, as the rail discussed above.
According to a further aspect of the disclosure there is presented a material handling vehicle wherein said detecting devices are arranged such that they are operable to send a signal to the control unit and the control unit is arranged to control steering of the vehicle, when following the wall-ribbon, wherein said control of the steering is arranged such that the detected distance to the first or the second side can be kept essentially constant.
The advantage of allowing the signals from the detecting devices to the control unit and thus allowing for the control unit to control steering of the vehicle when following the wall-ribbon, is that the steering can be very precise. This allows for a more secure steering than for example if indications is disclosed for an operator, that then steers the vehicle.
According to a further aspect of the disclosure there is presented a material handling vehicle wherein the detecting devices are installed on the lower part of a chassis of the vehicle. It is preferred that said detecting devices comprises at least one contactless sensor device. The detecting devices have a field of detection in the shape of an triangle that is extending away from the first side 9 and/or the second side at an maximal angle of 100°, preferably 90° or even more preferred 45°, most preferred 30°, most preferred 20°, or wherein a field of detection is a pin-like field achieved by means of a laser device.
The lower part of the vehicle is particularly suitable as the wall-ribbon should be positioned low down on a warehouse rack as it might otherwise prevent the use of the position in the warehouse rack where the wall-ribbon extend past, such as the lowest position in the warehouse rack.
The advantage with using contactless sensors is that the set up and sensitivity of the sensors is made in an efficient manner. Also the wall-ribbon basically need only to be a very simple detectable stripe.
The contactless sensor devices used only need to be able to detect the wall-ribbon while in the aisle. In order to be able to centre the material handling vehicle in the aisle. Thus the sensors need primarily only to determine the distance to the wall-ribbon. Thus by not applying a very complex sensor the installation can be made simple and mainly focus on the monitoring of the distance from the sides of the vehicle. And as the aisle is very narrow, just broader than the material handling vehicle itself the sensors need only be able to be efficient on very low distances 0,1-1,0 dm. Thus a simple but efficient sensor is only required. Installation of the detecting devices on the lower part of a chassis provides several advantages. As the wall-ribbon is to be detected it is preferred that it does not prevent the use of certain load spaces in the warehouse rack. Thus it is preferred that the wall-ribbon is positioned closer to the ground, thus the lowest slot of the warehouse rack can still be used for the a pallet or load. The field of view can thus need not be extremely broad, in fact a more narrow field of detection can be more precise than allowing for a very broad field of detection.
According to a further aspect of the disclosure there is presented a material handling vehicle that comprises four detecting devices two in the front and two in the back. It is preferred that there are comprised two detecting devices on the first side and two on the second side of the vehicle.
By applying four detecting devices there is increased safety as both the front part of the vehicle and the back part can be monitored for the distance to the wall-ribbon, i.e. the warehouse rack. Thus a more sensitive system is built. Also it will be more efficient to monitor four distances for the purpose of controlling the vehicle in the aisle in respect of the angle to the centre line following the aisle. By providing a sensor pair on each side in front to positioner in correct manner of the material handling vehicle in the aisle is easier. Also by proving sensors on the back section of a side or both sides a god positioning of the rear part of the material handling vehicle is possible.
According to a further aspect of the disclosure there is presented a material handling vehicle wherein at least one of the detecting devices comprises a pin that extend outside the first and/or second side of the vehicle. It is preferred that at least two pins are comprised and at least one is positioned on the first side and at least one on the second side respectively. It is further preferred that the respective pin of the two pins has a length that will allow for respective the at least two pins on the first and second side of the vehicle at the same time to detect a wall-ribbon on respective side of the vehicle, or the pin has a length that will make it possible for respective at least two pins on the first and second side of the vehicle to engage the wall-ribbon on the first side at the same time as the pin disengages a wall-ribbon on the second side.
By using a pin as detecting device a particularly reliable and simple detection of the distance to the wall-ribbon in the aisle is achieved. As the length of the pin itself is a very simple distance measuring device. It is to be understood that the pin can be a very precise manner, as the pin can detect not only one distance to a wall-ribbon, the pin can bend or turn such that almost an analogue manner of detection of distance is achieved. Also a maximal length can be calibrated to the width of the aisle in order to achieve a detection on both sides of the aisle when the material handling vehicle is correct positioned that is straight in the aisle. It should be understood that contactless sensor devices can be combined in any number with the pin type of detecting devices.
According to a further aspect of the disclosure there is presented a material handling vehicle wherein said pin or pins comprises a spring and an rotating centre that allows for the pin or pins to move slightly around said centre when in contact with a wall-ribbon. It is preferred that the angle of the pin to the first and/or second side of the material handling vehicle can be adjusted for adjusting the detected distance outside the first and/or second side of the material handling vehicle.
By making the pins rotatable it is possible to have an adaptation of the force that the pin will apply to the wall-ribbon. This will make it easier to prevent that the wall-ribbon is damaged by the pins. Also the other way around is safeguarded, i.e. that the pins are bent by the wall-ribbon. This is of course important in terms of safety as a bent or broken pin would jeopardize the distance measuring feature. Also the distance can be adjusted by adjusting the angle in relation to the side of the material handling vehicle. Also the detection can be made in an analogue manner. Thus it is possible to detect a decrease in distance as well as an increase in distance and in that way controller the distance to the wall-ribbon in a very precise manner.
According to a further aspect of the disclosure there is presented a material handling vehicle wherein said pin is flexible, preferably the pin itself comprises at least one switch for detecting contact by the pin with the wall-ribbon by actuation of said switch.
By providing flexibility to the pin itself it is possible to provide a very simple attachment of the pin to the vehicle. In particular it will provide less wear on the wall-ribbon if the pin is flexible. Also the pin need not to have a spring attachment to the material handling vehicle. Also any risk of damage to the wall-ribbon by the pin is lowered.
According to a further aspect of the disclosure there is presented a material handling vehicle wherein said pin has an idle position that is angled backwards towards the backside of the material handling vehicle.
By having the pins angled backwards the forward driving in the aisle will be less prone to damage the pins. Thus if the aisles allows for a separated entrance and exit the angled pins will be less affected by having less possibility to be exposed to forces in the longitudinal direction of the pin.
According to a further aspect of the disclosure there is presented a material handling vehicle wherein at least one further detecting device is provided on either of the first or the second side wherein this detecting device comprises a camera, preferably a 3D camera.
By also applying a three dimensional camera it will be possible to monitor the wall-ribbon both for maintenance purposes but also for control of the vehicle in the aisle.
According to a further aspect of the disclosure there is presented a warehouse rack that it is modified with a wall-ribbon, said wall-ribbon having a length such that it can extend between two upright beams of the warehouse rack and that the wall-ribbon has a vertical height that is less than the distance between two consecutive horizontal beams in vertical direction in the warehouse rack, such that the wall-ribbon does not prevent a load to be positioned in the warehouse rack, and that the wall-ribbon is mounted so that it that extends along the warehouse rack in a parallel manner, close to or in contact with the floor of a warehouse, preferably said wall-ribbon is arranged such that it is mountable to the warehouse rack itself, even more preferred by providing the warehouse rack with a screw attachment arrangement and/or an adhesive attachment arrangement and/or a weld attachment arrangement, said wall-ribbon is preferred to have a weight per meter length of 0,01-10 kg/meter, preferably 0,01-5 kg/meter or even more preferred 0,01-2 kg/meter, even more preferred said wall-ribbon is not attached to the floor of the warehouse.
By applying a much simpler wall-ribbon the installation is simplified dramatically. And as the wall-ribbon can be installed directly to the warehouse rack no bolting to the floor is necessary. Thus a much more simplified installation of the aisle is achieved by using a wall-ribbon. It should be understood by applying the detecting devices as described above the control of the material handling vehicle is sufficiently good such that the wall-ribbon need not be able to withstand mechanical forces, and can be made in a much more simple manner than an ordinary rail in the aisle.
According to a further aspect of the disclosure there is presented a warehouse system comprising a material handling vehicle according to any aspect above and a warehouse rack according to the above.
The system is thus comprising two parts: the warehouse rack with the wall-ribbon and the material handling vehicle as modified. The system will be a very effective and adaptable system for material handling.
According to a further aspect of the disclosure there is presented a method for controlling a material handling vehicle comprising the steps of:

(I) compare a detected distance with a predetermined distance range, between a first longitudinal side of the material handling vehicle and a wall-ribbon attached to a warehouse rack,
(II) determine if the detected distance is within the predetermined distance range, control the vehicle to head straight forward in the longitudinal direction (8),
(III) determine if the detected distance is not within the predetermined distance range steer towards the wall-ribbon if the detected distance is larger than the predetermined distance range, steer away from the wall-ribbon if the detected distance is smaller than the predetermined distance range steer away from the wall-ribbon.

The method for controlling the vehicle is advantageous as it is so simple in implementation. By monitoring the sides of the vehicle with a very simple algorithm the safety and set up is fulfilled in simple manner. Also the advantages mentioned above is as always relevant. A simple wall-ribbon is sufficient for giving the necessary detection of the distance between the material handling vehicle and the warehouse rack.
According to a further aspect of the disclosure there is presented a computer software that when executed on a control unit of a material handling vehicle according to any of the aspects above, controls the material handling vehicle to perform the method according to the above.
It is preferred that the algorithm of the method is executed on a control unit of the material handling vehicle. This will give the possibility for easy adaptation of the steps of the method.
According to a further aspect of the disclosure there is presented computer program product comprising a storage medium on which the computer software according to the above is stored.
The computer program product will be easy to transport, and install on any material handling vehicle.
According to a further aspect of the disclosure there is presented a method for arranging a warehouse comprising the steps of:

(Ia) provide a material handling vehicle (1),
(IIa) provide the material handling vehicle (1) with at least one detecting device (18, 19) on a first or a second side (9, 10) of said vehicle,
(IIIa) provide at least one aisle comprising at least one warehouse rack (14, 15) comprising a wall-ribbon (12, 13) attached directly to the warehouse rack (14, 15),
(IVa) enter the aisle with the material handling vehicle (1),
(Va) detect the wall-ribbon (12, 13) on a first side (9) of the material handling vehicle (1),
(Via) use the detected value from the detecting device (18, 19), to follow the wall-ribbon (12, 13).

The final method is related to the easiness of modification of a material handling vehicle, thus an old already produced vehicle can easily be arranged to have the benefits of the discussed matter. For example the same type of software used for a wire guided VNA material handling vehicle can be used directly or with little adaptation for the material handling vehicle as modified. And further the arranging of a wall-ribbon on a warehouse rack will provide for a very efficient new warehouse.

LIST OF DRAWINGS

Fig. 1: Warehouse system according to the disclosure, including a material handling vehicle.
Fig. 2: Material handling vehicle according to the disclosure.
Fig. 3: Pin for the material handling vehicle according to the disclosure, with pin detecting devices.
Fig. 4: Material handling vehicle according to the disclosure, with contactless sensors.
Fig. 5: Angle of contactless sensors according to the disclosure.
Fig. 6: Pin-like field of detection according to the disclosure.
Fig. 7: Discloses a method of operating a material handling vehicle of the disclosure.

DETAILED DESCRIPTION

The present disclosure is related to a material handling vehicle that is capable to operate in an aisle. An aisle is in general a corridor made up of a long warehouse rack and a wall or often two warehouse racks as sides. A warehouse rack is to be understood a storing device for goods, pallets or the like that is used in a warehouse. In general the warehouse rack has several levels of storing goods, even if it could be only one level it is preferred to have many levels to save floor space. Thus the aisle is where the material handling vehicle operates in order to fetch goods. The goods can be particular items stored on a pallet or the whole pallet itself with the goods. In warehouses space is often desired to be used as efficient as possible, thus it is desired to have the warehouse racks as close to each other as possible. Thus the use of very narrow aisles have become very widely used in the logistic business and the warehouses. Thus the present disclosure is related to narrow aisles and the material handling vehicle used in the narrow aisle. The material handling vehicle thus has a load carrier, that generally can be in the form of a pair of forks. The load carrier can be arranged such that it is possible to move the load carrier in an angle of 180 degrees for picking up pallets on both sides of the vehicle, as well as in front of the vehicle. It is also possible to have an operator platform that is connected to the load carrier such that the operator can follow the load carrier as it is lifted. The material handling vehicle in general has an hydraulic system that is powered by a pump. The pump is in turn powered by a motor. The material handling vehicle in general also has a drive motor such that it can power one or several drive wheels below the material handling vehicle. Also further non powered wheels is arranged on the vehicle. There can also be support legs with wheels. The support legs may protrude in front of the vehicle such that a lifted load can have its point of gravity with in the surface made up by the wheels of the material handling. The material handling vehicle in general can have a control unit. The control unit is made up of at least a processor memory circuits and wiring. The control unit can control the different functions of the material handling vehicle. Thus the control unit is arrange to be able to control the speed and steering of the material handling vehicle through servo motors and other control devices. Thus the material handling vehicle is in general equipped with a steerable wheel that can be manually controlled by an operator, in particular outside aisle. When the material handling vehicle is inside an aisle the control unit is arranged such that it controls the steerable wheel, thus preventing the operator from manual control of the steerable wheel. In general the material handling vehicle modified can be a tiller truck, a very narrow aisle truck, an order picker, a stacker truck, a low lifting truck, a floor conveyor, a fork-lift truck, a reach truck or any other truck that can be operated in a narrow aisle in a warehouse. This implies that it is not a car, not a lorry-American English truck, not a tractor, not related to agricultural applications, or any other such application.
Figure 1 discloses a material handling vehicle 1 according to the present disclosure. The material handling vehicle 1 has entered an aisle 22. The material handling vehicle 1 has four main sides. It has a first side 9 and a second side 10. Both these sides limit the vehicle in transversal direction, at least for a major part of the length of the vehicle. There is also a front side 17 and a backside 11. The material handling vehicle 1 has a load carrier 2. A drive motor 3 is situated in the back section and is powering a drive wheel through a gear. There is an hydraulic motor 4 that powers an hydraulic pump 5, for a hydraulic system 6 that is used for lifting and lowering of the load carrier2. An energy source 23 is also incorporated. Preferably in the form of a battery, such as a lead acid battery or a Lithium Ion battery. Thus, the motors mentioned are electric. The material handling vehicle has a chassis 27 in the lower part of the vehicle 1.
The vehicle 1 is further arranged with detecting devices 18, 19, 20, 21, 24, 25, Fig. 1, Fig, 2, Fig, 4. It is disclosed with four detecting devices in Fig. 1 . However it should be understood that one detecting device on the first side 9 and the second side 10 is sufficient for operation. The detecting devices can detect the distance from the first side 9 to a wall-ribbon 12. The detecting devices can detect the distance from the second side 11 to another wall-ribbon 13. As seen in Fig. 1 there is exemplified a warehouse with two parallel warehouse racks 14, 15. It should be understood for the disclosure that an aisle can also be constituted by one wall and a warehouse rack, it need not be two warehouse racks. Thus the detecting devices can be used with one wall-ribbon 12, 13 on one side and a wall on the other side. By having four detecting devices it is possible to check the angle of the vehicle 1 at any moment, in that it is possible to compare four different distances to the respective side of the vehicle 1.
The detecting devices can be a pin 30, see figure 3. The pin 30 is preferably attached to the first 9 and second side 10 such that it extends outside the sides. The pin can have a centre 31 around which the it can rotate. A spring 26 can be used for giving the pin a spring function. The pin 30 have preferably an idle position in which it rests when the material handling vehicle 1 is not operating in a narrow aisle 22. The pin rotation of the pin 30 around the centre is preferred to be able to set. That is the end point of rotation, but also the force to come to the endpoint and also the angle at which the pin is idle and at the end point. The pins preferably are not very thick, they take the shape of feelers, pulps etc. They have preferably inbuilt switches and electronics such that the can detect when they are in contact with the wall-ribbon. The pins preferably also can detect a range from first contact until they are either rotated to the endpoint or bent to a maximal deflection. This detection is preferred to be made by electronic devices such as strain gauges, switches etc. The signals generated when detecting are preferred to be sent to the control unit 7. This can be made by a wireless protocol or by a wired CAN-Bus or the like.
The detecting devices can also be contactless sensor devices 24, 25, see Fig. 4. They are then installed in the same manner as the pins discussed above, i.e. on the lower part of the respective first 9 and second side 10. The field of detection need not be so broad for the contactless sensor devices 24, 25. As the distance between the side of the material handling vehicle 1 and the wall-ribbons in the aisle is very low in the order of 0,10 meter or the like. The an maximal angle of 100 ° is sufficient. But the angle can 90°,even more preferred 45°, Fig. 5. But it will be even sufficient with, most preferred 30 grader, most preferred 20 °. The field of view, or wherein a field of detection is a pin-like field 29 achieved by means of a laser device, Fig. 6. The pin-like field is thus a point like field only used for the determination of the distance 32, 33, from the first and/or second side 9, 10 to the wall-ribbon 12, 13, or wall. The pin-like field is preferably arranged by means of a laser detector. But in general the contact-less sensors can be ultra sound detector devices, radar detector devices, or any other type of contactless sensor devices that can determine a distance.
It is also possible to add a camera as a contactless sensor device, this can be used together with other types of detecting devices. In particular the camera can be a 3D camera, i.e. a three dimensional camera, in which case the camera can be used for determining distance itself. However the camera can also be used for monitoring the state of the wall-ribbon etc. thus giving added functionality to the contactless sensor devices.
As discussed relating to pin 30 detection above all the detecting devices being pins or contactless sensor devices are arranged to be able to communicate the detected values corresponding to distances 32, 33 to the control unit 7 of the material handling vehicle 1. And as stated this communication can be a wireless communication or a wired communication such as through a CAN-protocol.
It should also be understood that it is possible to combine a contactless sensor device, a pins, a camera etc. with each other on the same material handling vehicle (1) as detecting devices.
The control unit 7 of the material handling vehicle 1 is in general a truck computer that can be programmed for controlling the operating functions of the vehicle 1. Thus is has processor, memory, and all other circuits required for this control ability. Thus the detected values from the detection devices 18-21, 24, 25, is evaluated in the control unit 7 and the used for controlling the material handling vehicle 1, in the aisle 22. Thus an operator will not control the steering of the vehicle 1 in the aisle 22. I.e. in the aisle the control unit 7 is arranged to control a steerable wheel 35 of the material handling vehicle 1 and prevent an operator from manually controlling the steerable wheel 35. Outside a narrow aisle the manual control of the steerable wheel is in general not restricted and the operator can thus steer the material handling vehicle by controlling the steerable wheel 35.
The Wall-ribbon 12, 13 is intended to mean a device with a continuous flat surface that follows the warehouse rack 14, 15. It has a height and a length and a thickness. The length is the same as the horizontal length of the aisle the wall-ribbon is extending along. The thickness of the wall-ribbon is dependent on which material it is designed from. If made from metal, such as steel, the wall-ribbon has a thickness that is considerably lower than a rail shaped for mechanically controlling a material handling vehicle in the aisle. For example the wall-ribbon can have a thickness of 3 mm or 5 mm. However if made in paper, plastic or wood the thickness can vary. It should be possible to attach the wall-ribbon directly to the warehouse rack 14, 15. This should be made in the lower part of the warehouse rack 14, 15. For example adjacent the floor surface. The height of the wall-ribbon can be the same as for the know rails for narrow aisles, one such height is for example 5-15 cm. It should be understood that a rail intended for mechanical controlling of a material handling vehicle in the aisle could also be used as a wall-ribbon however this would not give the advantages of the wall-ribbon. The wall-ribbon should be easy to install and thus should be lighter than 15 kg/meter at a height of 0,10 meter. Preferably it should be less than 5 kg per meter at same height. It is to be understood that the wall-ribbon is needed for having an element to determine the distance to between the material handling vehicle 1 and the warehouse rack 14, 15. But at the same time there is no need for the wall-ribbon to be able to withstand an impact from the material handling vehicle 1. And the detecting devices provides for the avoidance of these impacts. Also it is simple to install the wall-ribbon compared with a wire guidance system where wires are milled into the floor.
The disclosure is thus also related to the warehouse rack 14, 15 itself, Fig 1. Thus the warehouse rack 14 has been modified with a simple wall-ribbon as described above. The wall-ribbon can preferably be as discussed directly attached to the warehouse rack 14, 15. Thus no drilling into the floor being required for installation of the wall-ribbon. Thus, it must be understood that the warehouse rack and the wall-ribbon will provide for a narrow aisle that would not function with the mechanically controlled vehicles. The wall-ribbon will not have strength enough to mechanically control a vehicle with rolls on the side. The wall-ribbon is thus apt at replacing a centre positioned sling that needs to be milled into the floor of the aisle, if used with a material handling vehicle 1 according to the present disclosure.
Thus, the disclosure is related to a warehouse system 40 that includes a warehouse rack 14,15, a wall-ribbon 12, 13 and a material handling vehicle 1 adapted for the operating in the aisle created by the warehouse racks 14, 15.
The disclosure is also related to a method for controlling the discussed material handling vehicle 1. In general the method is disclosed in Figure 7. There are four steps disclosed I-III.
The first step I is to detect distance on a first longitudinal side 9 to a warehouse rack 14. The warehouse rack 14 is provided with a wall-ribbon 12. The detected distance is compared with a predetermined distance range. The predetermined distance range is set according to the operation of the material handling vehicle in the warehouse. In general terms the distance range is comprised between 0,01 meter and 0,02 meter, but could be any desired range.
In step II it is determined whether the distance from the first side to the wall-ribbon 12 is within the predetermined distance range. If decided so, the material handling vehicle is controlled to proceed in the same direction as previously measurements or the heading when the material handling vehicle entered the aisle. If the distance as detected is not within the predetermined distance range, the material handling vehicle is controlled to steer towards the wall-ribbon if the distance is larger than the predetermined distance range. If it is detected that the distance to the wall-ribbon is less than the predetermined distance range it is controlled to steer away from the wall-ribbon. It is also thinkable to expand the method by comparing with a predetermined distance on the other side of the material handling vehicle, by means of a second detection device. Then the comparison with both these detecting devices will control the vehicle to take a straight heading when both detectors detect that the distance to the respective wall-ribbon is within the predetermined respective distance range. The material handling vehicle 1 is thus centred on the centre line 34 of the aisle 22, Fig. 1. The method is continuously repeated as long as the vehicle 1 is in the aisle 22. Of course the method can be extended with numerous different steps, such as if several detecting devices on the sides of the vehicle is present. Then the different values of detection devices of the same side can be compared with each other so as to determine a mean value of the distance of this side to its wall or wall-ribbon. The same determination can be made on the other side of the vehicle. Thus angles can be calculated and the steering manoeuvre can be very precisely controlled by setting an angle at the beginning of the steering manoeuvre that will achieve the quickest way to centre the vehicle in the aisle.
A computer software is preferred to be installed in the control unit 7 of the material handling vehicle 1 so as to perform the method as discussed above.
A computer program product can be achieved by storing the said software above in a device for storing such as a server, USB-stick, or in another material handling vehicle, or any other appropriate storage medium.
The disclosure is further related to a method where a material handling vehicle is modified into the material handling vehicle 1 of this disclosure. There are then seven steps disclosed la-Vila. Thus it is intended that an already existing material handling vehicle is provided in step la. In an ensuing step IIa the vehicle is provided with detecting devices on the longitudinal sides. Also there is a step IIIA of providing a warehouse rack 14, 15 provided with a wall-ribbon 12,13. In the next step IVa the so modified material handling vehicle is entered into an aisle. In ensuing step Va the wall-ribbon is detected on the first side (9). In a next step Via the wall-ribbon is detected on the second side of the vehicle 1. And in a final step Vila the vehicle is centred in the aisle by comparing the values of the first and second side detection devices. Thus also a vehicle as modified is usable for the above disclosure. It should be pointed out that the modified vehicle can be used with all the method steps as discussed in previous sections.

Claims

Material handling vehicle (1), comprising:
a load carrier (2), preferably a pair of forks,

a drive motor (3),

a hydraulic motor (4) powering an hydraulic pump (5),

a hydraulic system (6) pressurized by said pump,

an energy source (23) for powering the vehicle and its motors,

a control unit (7),

wherein said load carrier (2) is arranged by means of the hydraulic system to lift a load, the material handling vehicle (1) have a longitudinal direction (8) and a transversal direction (16), a first side (9) extending parallel with the longitudinal direction, a second side (10) extending in parallel with the longitudinal direction, a back side (11) transversal to the longitudinal direction, a front side (17) transversal to the longitudinal direction,

characterized in that

the material handling vehicle (1) comprises detecting devices (18, 19, 20, 21; 24, 25) on the first side (9) and the second side (10), wherein the detecting devices (18, 19, 20, 21; 24, 25) are arranged such that they are able to detect a wall-ribbon (12, 13) that extend in parallel with a warehouse rack (14, 15), and further the detecting devices (18, 19, 20, 21; 24, 25) are arrange to be able to detect a distance (32, 33) from at least one of the first side (9) or the second side (10) to the wall-ribbon (12, 13).
Material handling vehicle (1) according to claim 1, wherein said detecting devices are arranged such that they are operable to send a signal to the control unit (7) and the control unit (7) is arranged to control steering of the vehicle (1), when following the wall-ribbon (12, 13), wherein said control of the steering is arranged such that the detected distance to the first or the second side (9, 10) can be kept essentially constant.
Material handling vehicle (1) according to claim 1 or 2, wherein the detecting devices (18, 19, 20, 21; 24, 25) are installed on the lower part of a chassis (27) of the vehicle, preferably said detecting devices comprises at least one contactless sensor device (24, 25) wherein the detecting devices (18, 19, 20, 21; 24, 25) have a field of detection in the shape of an triangle (28) that is extending away from the first side (9) and/or the second side (10) at an maximal angle of 100°, preferably 90° or even more preferred 45°, most preferred 30°, most preferred 20°, or wherein a field of detection is a pin-like field (29) achieved by means of a laser device.
Material handling vehicle (1) according to any of the claims above, wherein the material handling vehicle (1) comprises four detecting devices (18, 19, 20, 21; 24, 25), two in the front and two in the back, preferably two on the first side (9) and two on the second side (10) of the vehicle (1).
Material handling vehicle (1) according to any of the claims above, wherein at least one of the detecting devices (18, 19, 20, 21) comprises a pin (30) that extend outside the first and/or second side (9,10) of the vehicle (1), preferably at least two pins are comprised and at least one is positioned on the first side (9) and at least one on the second side (10) respectively, preferably the respective pin (30) of the two pins (30) has a length that will allow for respective the at least two pins on the first and second side (9, 10) of the vehicle (1) at the same time to detect a wall-ribbon (12, 13) on respective side (9, 10) of the vehicle (1), or the pin (30) has a length that will make it possible for respective at least two pins on the first and second side (9, 10) of the vehicle (1) to engage the wall-ribbon (12) on the first side (9) at the same time as the pin disengages a wall-ribbon (12, 13) on the second side (10).
Material handling vehicle (1) according to claim 5, wherein said pin or pins (30) comprises a spring (26) and an rotating centre (31) that allows for the pin or pins (30) to move slightly around said centre (31) when in contact with a wall-ribbon (12, 13), preferably the angle of the pin (30) to the first and/or second side (9, 10) of the material handling vehicle (1) can be adjusted for adjusting the detected distance (32, 33) outside the first and/or second side (9, 10) of the material handling vehicle (1).
Material handling vehicle (1) according to claim 5 or 6, wherein said pin (30) is flexible, preferably the pin itself comprises at least one switch for detecting contact by the pin (30) with the wall-ribbon by actuation of said switch.
Material handling vehicle (1) according to any of the claims 5 - 7, wherein said pin (30) has an idle position that is angled backwards towards the backside (11) of the material handling vehicle (1).
Material handling vehicle (1) according to any of the claims above, wherein at least one further detecting device is provided on either of the first or the second side (9, 10) wherein this detecting device comprises a camera, preferably a 3D camera.
Warehouse rack (14, 15) characterized in that it is modified with a wall-ribbon (12,13), said wall-ribbon having a length such that it can extend between two upright beams of the warehouse rack and that the wall-ribbon has a vertical height that is less than the distance between two consecutive horizontal beams in vertical direction in the warehouse rack, such that the wall-ribbon does not prevent a load to be positioned in the warehouse rack (14, 15), and that the wall-ribbon (12, 13) is mounted so that it that extends along the warehouse rack (14, 15) in a parallel manner, close to or in contact with the floor of a warehouse, preferably said wall-ribbon (12,13) is arranged such that it is mountable to the warehouse rack (14, 15) itself, even more preferred by providing the warehouse rack (14, 15) with a screw attachment arrangement and/or an adhesive attachment arrangement and/or a weld attachment arrangement, said wall-ribbon (12, 13) is preferred to have a weight per meter length of 0,01-10 kg/meter, preferably 0,01-5 kg/meter or even more preferred 0,01-2 kg/meter, even more preferred said wall-ribbon is not attached to the floor of the warehouse.
Warehouse system (40), comprising a material handling vehicle (1) according to any of the claims 1-9 and a warehouse rack (14, 15) according to claim 10.
Method for controlling a material handling vehicle (1) according to any of the claims 1-9, comprising the steps of:
• (I) compare a detected distance (32) with a predetermined distance range, between a first longitudinal side (9, 10) of the material handling vehicle (1) and a wall-ribbon (12, 13) attached to a warehouse rack (14),

• (II) determine if the detected distance is within the predetermined distance range, control the vehicle (1) to head straight forward in the longitudinal direction (8),

• (III) determine if the detected distance (32, 33) is not within the predetermined distance range steer towards the wall-ribbon (12, 13) if the detected distance is larger than the predetermined distance range, steer away from the wall-ribbon (12-13) if the detected distance is smaller than the predetermined distance range steer away from the wall-ribbon (12, 13).
Computer software that when executed on a control unit (7) of a material handling vehicle (1) according to any of the claims 1-9, controls the material handling vehicle (1) to perform the method according to claim 12.
Computer program product comprising a storage medium on which the computer software according to claim 13 is stored.
Method for arranging a warehouse comprising the steps of:
• (Ia) provide a material handling vehicle (1),

• (IIa) provide the material handling vehicle (1) with at least one detecting device (18, 19) on a first or a second side (9, 10) of said vehicle,

• (IIIa) provide at least one aisle comprising at least one warehouse rack (14, 15) comprising a wall-ribbon (12, 13) attached directly to the warehouse rack (14, 15),

• (IVa) enter the aisle with the material handling vehicle (1),

• (Va) detect the wall-ribbon (12, 13) on a first side (9) of the material handling vehicle (1),

• (Via) use the detected value from the detecting device (18, 19), to follow the wall-ribbon (12, 13).