Abstract:
A remotely operated vehicle suitable for picking up storage bins from an underlying storage system. The vehicle includes driving means situated at or at least partly within rolling means of the vehicle, providing rolling set specific driving force to the vehicle in either the first direction or the second direction.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to a remotely operated vehicle, or robot, for picking up storage bins from a storage system as defined in the preamble of claim  1  and a storage system for storage of bins. 
       BACKGROUND AND PRIOR ART 
       [0002]    A remotely operated vehicle for picking up storage bins from a storage system is known. A detailed description of a relevant prior art storage system is presented in WO 98/49075, and details of a prior art vehicle being suitable for such a storage system is disclosed in detail in Norwegian patent NO317366. Such prior art storage systems comprise a three dimensional storage grid containing storage bins that are stacked on top of each other up to a certain height. The storage grid is normally constructed as aluminium columns interconnected by top rails, onto which a plurality of remotely operated vehicles, or robots, are arranged to move laterally. Each vehicle is equipped with a lift for picking up, carrying, and placing bins that are stored in the storage grid, and a rechargeable battery in order to supply electrical power to a vehicle incorporated motor. The vehicle typically communicates with a control system via a wireless link and is recharged at a charging station when needed, typically at night. 
         [0003]    An example of a prior art storage system is illustrated in  FIG. 1 . The storage system  3  includes a plurality of vehicles or robots  1  configured to move in X and Y directions (see Cartesian coordinate system  100 ) on dedicated supporting rails  13 , and to receive a storage bin  2  from a storage column within a bin storing grid  15 . The prior art storage system  3  may also include a dedicated bin lift device  50 , the latter being arranged to receive a storage bin  2  from a vehicle  1  at the top level of the storage system  3  and to convey the storage bin  2  down in a vertical direction to a delivery station, or port  60 . 
         [0004]    However, with this known system each vehicle is covering a cross section of the underlying storage system that corresponds to two storage columns, thereby limiting the maximum number of simultaneously operating vehicles. 
         [0005]    It is thus an object of the present invention to provide a vehicle and a storage system that allows a significant increase in the number of simultaneously operating vehicles during successful handling of storage bins. 
       SUMMARY OF THE INVENTION 
       [0006]    The present invention is set forth and characterized in the main claim, while the dependent claims describe other characteristics of the invention. 
         [0007]    In particular, the invention concerns a remotely operated vehicle suitable for picking up storage bins from an underlying storage system, comprising a vehicle lifting device suitable for lifting the storage bin from the underlying storage system, a first vehicle rolling means comprising a first rolling set and a second rolling set arranged at opposite facing side walls of a vehicle body, allowing movement of the vehicle along a first direction (X) on the underlying storage system during use, and a second vehicle rolling means comprising a first rolling set and a second rolling set arranged at opposite facing side walls of the vehicle body, allowing movement of the vehicle along a second direction (Y) on the underlying storage system during use, the second direction (Y) being perpendicular to the first direction (X), and wherein each of said rolling sets comprises at least two wheels. The first and second rolling sets may also include belts, chain tracks or any other mechanisms or combination of mechanisms that enables movement of the vehicle forward and/or backwards on the underlying storage system. 
         [0008]    The vehicle further comprises a first driving means situated at or at least partly within the first vehicle rolling means and being suitable for providing rolling set specific driving force to the vehicle in the first direction (X), a second driving means situated at or at least partly within the second vehicle rolling means and being suitable for providing rolling set specific driving force to the vehicle in the second direction (Y) and motor control electronics arranged within the volume between two of the wheels of each rolling set, which motor control electronics are configured to supply electric power to the first and second vehicle rolling means. During use, at least one of the first and second vehicle rolling means are in contact with the underlying storage system. 
         [0009]    In an advantageous embodiment at least one of the driving means comprises an electric motor using permanent magnets such as a brushless electric DC (direct current) motor. 
         [0010]    In another advantageous embodiment at least one of the first and second driving means comprises rotor magnets arranged at the inner surface of the outer periphery of their/its respective vehicle rolling means. 
         [0011]    In another advantageous embodiment the at least one of the first driving means and the second driving means comprises a stator arranged at least partly, preferably fully, within the same rotational plane as the vehicle rolling means and at least partly, preferably fully, within the vehicle body. Rotational plane signifies in this embodiment the plane extending perpendicular from the rotational axis of the vehicle rolling means. 
         [0012]    In another advantageous embodiment the vehicle comprises means suitable for measuring (at least indirectly) electromotive force (emf) of at least one of the vehicle rolling means, the means being in signal communication with one of the stator and the rotor, thereby allowing rolling set specific velocity registration of the vehicle during operation. For example, a back-emf measurement circuit may be installed in signal communication with the vehicle rolling means. A hall sensor may be used as an alternative or in combination. 
         [0013]    In another advantageous embodiment the vehicle comprises a rotary encoder (at least indirectly) connected to at least one of the first and second vehicle rolling means, thereby allowing angular position feedback during operation. Such rotary encoders is suitable for conversion of the angular motion of the vehicle rolling means to an analog or digital code. The rotary encoders (or shaft decoders) may be of type absolute rotary encoder and/or absolute multi-turn encoder. Said absolute rotary encoder may be at least one of a mechanical encoder, an optical encoder, a magnetic encoder and a capacitive encoder. Furthermore, the absolute multi-turn encoder may be at least one of a battery-powered multi-turn encoder, a geared multi-turn encoder, and a self-powered multi-turn encoder. 
         [0014]    In another advantageous embodiment the rotary encoder is a rotary encoder disk arranged within the outer periphery of the at least one of the first and second vehicle rolling means, preferably between the outer periphery and the rotor magnets. 
         [0015]    In another advantageous embodiment the vehicle further comprises means suitable for measuring acceleration of at least one of the first and second vehicle rolling means, them means being in signal communication with the stator. Such a means comprises preferably one or more piezoelectric sensors, for example an accelerometer from PCB™ Piezotronics. One or more inductive sensors may be used as an alternative to piezoelectric sensor(s), or in combination with piezoelectric sensor(s). 
         [0016]    In another advantageous embodiment each rolling sets comprises at least two wheels, and the vehicle further comprises motor control electronics arranged within the volume between two of the wheels of each rolling set. Said motor control electronics are in this embodiment configured to supply electric power to the first and second vehicle rolling means, and may preferably also transmit communication signals. 
         [0017]    In another advantageous embodiment the first vehicle rolling means comprises four X-wheels having their direction of revolution in the first direction and the second vehicle rolling means comprises four Y-wheels having their direction of revolution in the second direction, wherein each of the X-wheels and each of the Y-wheels is drivingly connected to the first driving means and the second driving means, respectively. Each of the wheels comprises preferably a plurality of rotor magnets (for example in the form of a rotor magnet disc) arranged within the inner surface of the wheels outer periphery and a plurality of stators (for example in the form of a stator disc) arranged at least partly, for example fully, within the vehicle body, preferably at the same or nearly the same height has the location of the wheels rotational axis. The height is in this document referring to the distance from the topmost point of the underlying storage system during use. Said stators include both windings and yoke, and the stator field windings are following the outer periphery of the wheels. 
         [0018]    In another advantageous embodiment at least part of, and preferably all of, the driving means is arranged within the wheels outer periphery. 
         [0019]    For example, when four belts are applied in order to drive the inventive vehicle in the X and Y-directions, a total of four motors may be installed in operative engagement with each of the four belts, thereby achieving the desired rolling set specific driving force. Likewise, when eight wheels are applied in order to drive the vehicle in the X- and Y-directions, a total of eight motors may be installed in operative engagement with each of the eight wheels, thereby achieving the desired rolling set specific driving force. 
         [0020]    In invention also concerns a storage system suitable for storage of bins. The storage system comprises a bin storing structure comprising a plurality of storage columns, where each storage columns is arranged to accommodate a vertical stack of storage bins and a remotely operated vehicle in accordance with any of the above mentioned embodiments. 
         [0021]    In the following description, specific details are introduced to provide a thorough understanding of embodiments of the claimed vehicle and storage system. One skilled in the relevant art, however, will recognize that these embodiments can be practiced without one or more of the specific details, or with other components, systems, etc. In other instances, well-known structures or operations are not shown, or are not described in detail, to avoid obscuring aspects of the disclosed embodiments. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0022]      FIG. 1  is a perspective view of a prior art storage system comprising a grid and a plurality of remotely operated vehicles/robots; 
           [0023]      FIG. 2  is a perspective view seen from above of a remotely operated vehicle according to one embodiment of the invention; 
           [0024]      FIG. 3  is a perspective view of the vehicle in  FIG. 2 , seen from below; 
           [0025]      FIG. 4  is a cross-sectional view of the vehicle in  FIGS. 2 and 3  seen along one principal orientation of the vehicle; 
           [0026]      FIG. 5  is a perspective view of the storage system seen from above in accordance with one embodiment of the invention, where the inventive vehicles are shown arranged directly above five neighbouring storage columns; 
           [0027]      FIGS. 6  A and B are cross-sectional view of the storage system in  FIG. 5  showing the inventive vehicles above neighbouring columns along the two principal orientations of the vehicles; 
           [0028]      FIG. 7  is a perspective view of a rolling set constituting part of the vehicle in accordance with one embodiment of the invention; 
           [0029]      FIGS. 8  A and B are perspective views of a wheel constituting part of the vehicle in accordance with one embodiment of the invention; and 
           [0030]      FIGS. 9  A, B and C illustrate the rolling set in  FIG. 7  having one of the wheels removed, where  FIGS. 9  A and B are cross-sectional views of the rolling set seen along each of the principal orientations of the vehicle and  FIG. 9  C is a perspective side view of the part of the rolling set of which the wheel has been removed. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0031]    All relative terms used to describe the inventive vehicle (hereinafter referred to as the robot) such as upper, lower, lateral, vertical, X-direction, Y-direction, Z-direction, etc, shall be interpreted using the above mentioned prior art storage system ( FIG. 1 ) as reference system. For the sake of clarity the X, Y and Z-directions are illustrated by a Cartesian coordinate system  100  in  FIGS. 1-7 and 9 . 
         [0032]      FIGS. 2 and 3  give perspective views in two different angles of a robot  1  comprising a rectangular vehicle body or framework  4  displaying a cavity centrally arranged there within, a top lid  72  covering the top part of the body  4 , a first vehicle rolling means  10  comprising four X-wheels  101 - 104  for movement in the X-direction on the supporting rails  13  of the underlying bin storing grid  15  and a second vehicle rolling means  11  comprising four Y-wheels for movement in the Y-direction on the supporting rails  13  of the underlying bin storing grid  15 , in which both the first and second rolling means  10 , 11  are mounted at the exterior walls of the body  4 . The size of the cavity within the robot  1  ( FIG. 3 ) is adapted to contain at least the main part constituting the largest storage bin  2  intended to be picked up by the robot  1 , most preferably the entire bin. The operation of picking up storage bins  2  is performed by a lifting device  7  shown in a retracted position at the top end of the cavity of  FIG. 3 . 
         [0033]      FIG. 4  shows a cross section of the robot  1  when observed along the X-direction. 
         [0034]      FIGS. 5 and 6  show part of the storage system  3  in which the robots  1  are arranged in various neighbouring positions on top of the bin storing grid  15 . In four of the five positions, the robot  1  is arranged directly above the grid&#39;s  15  storage columns. As most apparent in  FIGS. 6  A and B, which shows the storage system  3  of  FIG. 5  in a cross-sectional view along Y-direction and X-direction, respectively, the robots  1  are dimensioned so that the maximum cross sectional area along the X-Y plane occupies not more than the cross sectional area of the corresponding (underlying) storage column. Hence, two or more robots  1  may be operated simultaneously above neighbouring columns of the grid  15 , liberating more space compared to prior art systems. 
         [0035]    One side of the first vehicle rolling means  10  is illustrated in  FIG. 7  in a perspective side view. The rolling means  10  comprises in this particular embodiment of the invention two wheels  101 , 102  with outer rims/edges  9  situated near the corners of the vehicle body  4  along the X-direction. A cover plate  25  constituting part of the vehicle body  4  is arranged between the two wheels  101 , 102 . 
         [0036]    Further details of one of these wheels  101 , 102  are provided in  FIGS. 8  A and B, showing the outer side and the inner side, respectively. In  FIG. 8B  a rotary encoder  23  of type optical rotary quadrature encoder has been arranged within the inner radial surface of the outer rim  9 . Other types of encoders may be used such as magnetic encoders, linear encoders, voltage based analog encoders, etc. A rotor  5 , in  FIG. 8B  shown as a set of permanent magnets  5 , is arranged inside the circumference set up by the rotary encoder  23 , i.e. closer to the rotational axis of the wheel  101 . 
         [0037]    The corresponding stator  19  is seen in  FIG. 9  in the form of electrical windings  19   a  wrapped around yokes  19   b . However, a skilled person will understand that the stator  19  and rotor  5  may (in other embodiments of the invention) be configured with stator magnets and rotor yokes/windings, respectively. 
         [0038]      FIGS. 9  B and C also illustrate an arrangement where means for measuring acceleration  24  is connected in signal communication with the stators  19  of each wheel  101 , 102 , for example by use of piezoelectric sensors.  FIG. 9  A is a cross section of part of the first vehicle rolling means  10  seen along the X-direction, illustrating stator  19  being enclosed by the outer rim  9 . 
         [0039]    All components and their interactions/configurations may be valid also for the second vehicle rolling means  11 . 
         [0040]    The fact that the driving means  5 , 19  are arranged near or within the rolling means  10 , 11  of the robot  1  contribute to liberate space on the storage system during operation, thereby allowing a more compact design of the robot  1  compared to prior art robots. 
         [0041]    All operations of the robot  1  are controlled by wireless communication means and remote control units. This includes one or more of control of the robot movement, control of the vehicle lifting device  7 , measurements of robot positions, measurements of robot velocities and measurements of robot accelerations. 
         [0042]    In the preceding description, various aspects of the vehicle and the storage system according to the invention have been described with reference to illustrative embodiments. For purposes of explanation, systems and configurations were set forth in order to provide a thorough understanding of the system and its workings. However, this description is not intended to be construed in a limiting sense. Various modifications and variations of the illustrative embodiments, as well as other embodiments of the system, which are apparent to persons skilled in the art to which the disclosed subject matter pertains, are deemed to lie within the scope of the present invention. 
       LIST OF REFERENCE NUMERALS 
       [0000]    
       
           1  Remotely operated vehicle/robot 
           2  Storage bin 
           3  Storage system 
           4  Vehicle body/framework 
           5  Rotor/permanent magnets 
           7  Lifting device 
           9  Outer rim/outer periphery of rolling means 
           10  First vehicle rolling means/first set of wheels 
           11  Second vehicle rolling means/second set of wheels 
           13  Supporting rail 
           15  Bin storing grid 
           19  Stator 
           19   a  Windings 
           19   b  Yoke 
           23  Rotary encoder 
           24  Means for measuring acceleration/piezoelectric sensor 
           25  Cover plate 
           50  Bin lift device 
           60  Delivery station/port 
           72  Top lid 
           100  Cartesian coordination system 
           101  First X-wheel 
           101  Second X-wheel 
           102  Third X-wheel 
           103  Fourth X-wheel 
           111  First Y-wheel 
           112  Second Y-wheel 
           113  Third Y-wheel 
           114  Fourth Y-wheel