Patent Description:
The handling of goods in warehouses is becoming increasingly automated. Robotic ground conveyor vehicles are thereby typically used to transport load carrying pallets between stations in the warehouse. Such pallet carrying vehicles are known as automated mobile robots (AMR) or automated guided vehicles (AGV) and move autonomously on the floor of the warehouse. The vehicles may be guided by natural navigation, magnetic tracks or beacons in the warehouse and comprise a controller with instructions for controlling the movement of the vehicle. However, a general problem with known solutions is that there are few possibilities to transfer pallets to and from the carrying vehicle and therefore the transport flow in the warehouse is limited to particularly designed stations where the automated vehicle may leave or pick up pallets.

<CIT> relates to improving the efficiency of storing and retrieving articles from a warehouse and discloses automated guided in accordance with the pre-characterizing portion of appended claim <NUM>. <CIT> discloses a device that is configured such that goods loaded onto the device may either be lifted together with the device, or may be lifted without the device. The device may be designed such that it may be picked up by the forks of a fork-lift truck from any of its four sides. <CIT> discloses an adaptor for attachment to a conventional pallet such that a load may be lifted without lifting the pallet. The adaptor may be designed such that the forks of a fork-lift truck may engage from any of its four sides. <CIT> discloses a robotic pallet lifting device which makes use of scissor type lifting support surfaces which integrate within the lifting device in a transversely positioned manner.

It is an object of the present disclosure to provide a robotic ground conveyor vehicle which solves or at least mitigates at least one of the problems or drawbacks of the prior art.

In particular, it is an object of the present disclosure to provide a robotic ground conveyor vehicle which allows for flexible handling of goods.

According to the present disclosure, at least one of these objects is achieved by a robotic ground conveyor vehicle for transporting pallets comprising,.

The robotic ground conveyor vehicle provides advantages in that the spaced apart load support members allows loads, e.g. pallets, carried by the robotic ground conveyor vehicle to be accessed by forks of forklift trucks at all times and in all situations during a transporting operation. For example, if a robotic ground conveyor vehicle according to the present disclosure malfunctions between loading stations, a forklift truck may access the pallet carried by the robotic ground conveyor vehicle, lift it away from the robotic ground conveyor vehicle and transport the pallet further down the transport chain. The robotic ground conveyor vehicle according to the present disclosure further provides flexibility in transporting operations because designated loading/unloading stations in form of shelves or the like for the robotic ground conveyor vehicles may be omitted in the warehouse. It suffices that the robotic ground conveyor vehicle carries its pallet to a designated area where a forklift truck may lift the pallet off the robotic ground conveyor vehicle and place the pallet onto another ground conveyor vehicle. Alternatively, the forklift-truck may carry the pallet further in the transporting operation.

In the robotic ground conveyor vehicle according to the present disclosure, the loading surface extends in a longitudinal direction between a front end and a rear end of the robotic ground conveyor vehicle. The front end may thereby define the forward driving direction of the robotic ground conveyor vehicle and the rear end the backward driving direction. The load support members are spaced apart in the longitudinal direction of the loading surface. This allows advantageously the forks of a forklift truck to engage the pallet carried by the robotic ground conveyor vehicle.

By "engage a pallet" is meant that the forks of a forklift truck may be inserted into pallet channels of the pallet or inserted underneath the pallet that is supported on the load support members and lift the pallet away from the load support members. The pallet may thereby include longitudinal pallet channels, and/or transverse pallet channels and/or the baseboards of a pallet. In dependency of the type of pallet, the underside of the pallet may be a planar surface.

According to an alternative of the robotic ground conveyor vehicle, the load support members are discrete elements configured to be received in pallet channels of a pallet carried by the robotic ground conveyor vehicle. This configuration allows for a reduced total height of the robotic ground conveyor vehicle and the pallet carried. It also provides for secure transportation of the pallet.

The load support members are arranged in at least two rows, wherein each row comprises at least two load support members. The load support members are spaced apart such that an opening is formed between at least two adjacent load support members of each row. The opening is configured to receive at least one fork of a fork-lift truck. This configuration allows for simple and straight forward access, for a forklift truck, to the transverse pallet channels of a pallet carried by the forklift truck. The pallet may easily by positioned such that the openings between the adjacent load support members of both rows coincide with the transverse pallet channels.

According to an alternative of the robotic ground conveyor vehicle according to the present disclosure, the load support members are elongate and extend parallel to each other between opposing sides of the loading surface. This configuration provides from high flexibility because a pallet placed onto the support members may be accessed from any of its sides by forks of a forklift truck.

In detail, the load support members may extend transverse to the longitudinal extension of the loading surface. This configuration provides for secure transportation of a pallet on the robotic ground conveyor vehicle. It may further allow access to the baseboards of a pallet by forks of a forklift truck.

In more detail, the load support members may be spaced apart such that an opening is formed between at least two adjacent load support members, wherein the opening is configured to receive one or two forks of a forklift truck. This allows for full access to a pallet carried by the robotic ground conveyor vehicle. A forklift truck may engage both the longitudinal and transverse pallet channels and the base boards of the pallet carried by the robotic ground conveyor vehicle. The opening may be at least <NUM>/<NUM> the dimension of the pallet that is to be supported by the load support members.

The load support members may comprise an elongate support portion for supporting the underside of a pallet and a central portion extending between the loading surface and the elongate support portion. This configuration is advantageous in operation with loading/unloading stations having shelves for pallets.

Typically, the support members may be configured to support the base boards or the backside of a pallet carried by the robotic ground conveyor vehicle.

The loading surface may be configured to receive a pallet. The loading surface may be shaped and dimensioned to receive a pallet. The loading surface may be rectangular. The dimension of the loading surface may be approximately <NUM> x <NUM> or <NUM> x <NUM>.

The the loading surface may comprise support member openings for the load support members. Thereby the robotic ground conveyor vehicle may be advantageously compact in the vertical direction. The load support members may be vertically movable with respect to the loading surface.

The robotic ground conveyor vehicle according to the present disclosure will now be described more fully hereinafter. The robotic ground conveyor vehicle according to the present disclosure may however be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided by way of example so that this disclosure will be thorough and complete, and will fully convey the scope of the present disclosure to those persons skilled in the art. Same reference numbers refer to same elements throughout the description.

In the following, the robotic ground conveyor vehicle will be referred to as the "robotic vehicle".

<FIG> shows a robotic vehicle <NUM> for transporting pallets according to a first alternative of the present disclosure. The robotic vehicle <NUM> comprises a frame <NUM> which comprises a drive wheel <NUM> for propelling the robotic vehicle and support wheels <NUM> (see <FIG>). The frame <NUM> further comprises several components for controlling the robotic vehicle. These components are not visible in the drawings and include: A motor, such as an electric motor, for driving the drive wheel; mechanical elements for steering the drive wheel: hydraulic systems and/or electrical motors for powering movable parts of the robotic vehicle; a controller for controlling the movement of the robotic vehicle. The controller may be implemented using instructions that enable hardware functionality, for example, by using executable computer program instructions in a general-purpose or special-purpose processor that may be stored on a computer readable storage medium (disk, memory etc.) to be executed by such a processor. The controller is configured to read instructions from the memory and execute these instructions to control the operation of the robotic vehicle including, but not being limited to, the propulsion, steering and movement of movable parts of the robotic vehicle. The controller may be implemented using any suitable, publically available processor or Programmable Logic Circuit (PLC). The memory may be implemented using any commonly known technology for computer-readable memories such as ROM, RAM, SRAM, DRAM, FLASH, DDR, SDRAM or some other memory technology. The frame <NUM> may further comprise sensors for detecting objects in the environment of the robotic vehicle or the presence of guiding or beacons which supports the navigation of the robotic vehicle.

The robotic vehicle <NUM> further comprises a loading surface <NUM> which is planar and elongated and extends in longitudinal direction over the frame <NUM> of the robotic vehicle between the front end <NUM> and the rear end <NUM> of the robotic vehicle. The front end <NUM> is the forward driving direction and the rear end <NUM> is backwards driving direction of the robotic vehicle <NUM>.

The loading surface <NUM> is configured to receive a pallet <NUM>. Pallets come in various shapes and dimensions, such as rectangular or square, and the loading surface may be designed and dimensioned accordingly.

An example of a pallet <NUM> is shown in <FIG>. Thus, the pallet <NUM> has a planar floor <NUM> with an upper side <NUM> onto which goods may be placed. The backside <NUM> of the planar floor <NUM> is located opposite to the upper side <NUM> and may be attached to base boards <NUM> by spacers <NUM> which separates the planar floor <NUM> from the base boards <NUM>. The spacers <NUM> are arranged such that longitudinal pallet channels <NUM> are formed between first opposing ends of the pallet and/or such that transverse pallet channels <NUM> are formed through going between second opposing ends of the pallet. The longitudinal and/or transverse pallet channels may be dimensioned to receive load engagement elements, such as lifting forks of a lift truck. For example, a stacker lift-truck or reach lift-truck which are commercially available from the company Toyota Material Handling AB.

The backside <NUM> of the floor <NUM> and/or the longitudinal pallet channels <NUM>, and/or the transverse pallet channels <NUM>, and/or the base boards <NUM> constitute the underside of the pallet <NUM>. Examples of pallets include CHEP-pallets and EUR-pallets. Some types of pallets may only comprise longitudinal or only transverse pallet channels. In certain cases the pallet may not have pallet channels but rather a mere planar backside <NUM>.

Also shown in <FIG>, is a loading/unloading station <NUM> with two shelves <NUM> that are configured to carry a pallet <NUM>. The loading/unloading station <NUM> is dimensioned such that the robotic vehicle (not shown) may pass under the shelves <NUM> and leave a pallet <NUM> on the shelves <NUM> or remove a pallet from the shelves <NUM>. This operation will be described further below in the description.

Returning to <FIG>. The robotic vehicle <NUM> comprises a plurality of load support members <NUM> that are configured to support a pallet. By "plurality" is hereby meant two or more load support members <NUM>. In the embodiment shown in <FIG>, the load support members <NUM> are configured to be received in the longitudinal pallet channels <NUM> of a pallet <NUM> (not shown) that is to be carried by the robotic vehicle <NUM>.

<FIG> shows a front view of the robotic vehicle <NUM> and a pallet <NUM> that is supported on the load support members <NUM>. <FIG> further shows the loading/unloading station <NUM>. The load support members <NUM> are movable in vertical direction, upward/downward, so that a pallet <NUM> may be lifted up from the shelves <NUM> of the loading/unloading station <NUM> by the robotic vehicle in a loading operation. Or, set down on the shelves <NUM> by the robotic vehicle <NUM> in an unloading operation. Movement of the load support members <NUM> may be realized by hydraulic piston/cylinder arrangements or electric motors in the robotic vehicle <NUM> (not shown). The load support members <NUM> may be configured to support the backside of the pallet <NUM> when received in the pallet channels <NUM>, <NUM>. The load support members <NUM> may thereby have an at least partly planar upper surface <NUM>. The planar upper surface <NUM> may further be provided with a groove that allows the load support members <NUM> to support load cages or roller cage carriers, for example.

Returning to <FIG>. According to the present disclosure, the load support members <NUM> are arranged spaced apart from each other on the loading surface <NUM> such that a pallet <NUM> that is carried by the load support members <NUM> may be engaged by the forks of lift-truck (not shown) and lifted away from the robotic vehicle. In the embodiment of <FIG>, the load support members <NUM> are thereby arranged in two parallel rows <NUM>' and <NUM>" which extend in longitudinal direction of the loading surface <NUM> of the robotic vehicle <NUM>. Row <NUM>' comprises three spaced apart load support members <NUM>', <NUM>', <NUM>'. Row <NUM>" also comprises three spaced apart load support members <NUM>", <NUM>", <NUM>". As shown, row <NUM>' is spaced apart from row <NUM>" in transverse direction on the loading surface <NUM> such that the load support members of row <NUM>'and <NUM>" may be received in a respective longitudinal pallet channel <NUM> of a pallet <NUM> carried by the robotic vehicle <NUM> (see <FIG>). The load support members of rows <NUM>', <NUM>" are further spaced apart from each other in longitudinal direction on the loading surface <NUM> such that an opening <NUM> is formed between adjacent load support members <NUM>', <NUM>', <NUM>' of row <NUM>, and between load support members <NUM>", <NUM>", <NUM>" of row <NUM>". The opening <NUM> is sufficiently wide to receive a fork of a lift-truck. The openings <NUM> of row <NUM>' are aligned with the openings <NUM> of row <NUM>". This allows the forks of a forklift truck to be inserted through the openings <NUM> of both rows <NUM>', <NUM>".

<FIG> shows a side view of the robotic vehicle <NUM> and a pallet <NUM> that is supported on the load support members <NUM> of the robotic vehicle. It is clearly visible that a pallet <NUM> may be supported onto the load support members <NUM> such that the transverse pallet channels <NUM> are aligned with the openings <NUM> between adjacent support members of rows <NUM>' and <NUM>''. Thus, a lift-truck (not shown) may insert the forks through the openings <NUM> and into the transverse pallet channels <NUM> and thereby lift the pallet <NUM> away from the robotic vehicle <NUM>. In <FIG>, the backside <NUM> of the pallet is supported onto the upper surface <NUM> of the load support members <NUM>', <NUM>".

As is clear from <FIG>, the loading surface <NUM> comprises one support member opening <NUM> for each load support member <NUM>. The load support members <NUM> are vertically movable with respect to the loading surface <NUM>. The load support members <NUM> are vertically movable from a vertical position in which they are vertically aligned with or below the loading surface to a vertical position in which they protrude above the loading surface <NUM> to carry the pallet <NUM>. In <FIG>, the load support members <NUM> protrude through their respective support member openings <NUM>.

In the shown embodiment, the robotic vehicle <NUM> comprises six load support members <NUM> which are arranged in two parallel rows with three load support members <NUM> in each row. However, it is possible to arrange two or more load support members <NUM> spaced apart on the loading surface <NUM> such that the forks of a lift-truck may access a pallet that is carried by the robotic vehicle <NUM>. For example, the robotic vehicle may comprise four elements that for example are arranged in the corners of the loading surface. It is also possible to arrange eight load support members <NUM> that for example are arranged in two parallel rows which each comprises four individual support members. An advantage with many spaced apart load support members in comparison to few load support members is that the strain on the pallet is more evenly distributed. In accordance with the disclosed embodiment, these load support members may be arranged such that an opening is formed between adjacent support members and that this opening is sufficiently wide to receive one or two forks of a forklift truck.

<FIG> shows a second alternative of a robotic vehicle <NUM>' according to the present disclosure. The robotic vehicle <NUM>' according to the second alternative is to great extent identical with the robotic vehicle <NUM> according to the first alternative of the present disclosure. Therefore, in order to not unnecessarily burden the text, only differencing features are described hereinafter.

Thus, the robotic vehicle <NUM>' comprises at least a first and a second load support member <NUM>, <NUM> which are arranged spaced apart on the loading surface <NUM> of the robotic vehicle <NUM>'. The first and second load support members <NUM>, <NUM> are movable in vertical direction and configured to support a pallet <NUM> that is to be carried by the robotic vehicle <NUM>'. As shown in <FIG>, the load support members <NUM> are elongate and extend transverse over the loading surface <NUM> of the robotic vehicle <NUM>. That is, transverse to the longitudinal extension of the loading surface <NUM>. The upper surface of the respective load support member <NUM>, <NUM> may be flat to allow a pallet to rest on the load support members in a stable and secure manner. Typically, the load support members <NUM>, <NUM> extend between the opposing longitudinal sides of the loading surface <NUM>. The length of the load support members <NUM>, <NUM> may correspond to the transverse width of the pallet. For example, the length of the load support members <NUM>, <NUM> may be greater than half the transverse width of the loading surface <NUM> or approximately equal to the width thereof. The load support members <NUM>, <NUM> may be spaced apart, in the longitudinal extension of the loading surface <NUM>, such that an opening <NUM> is formed between the load support members <NUM>, <NUM>. The distance between the load support members <NUM>, <NUM> may thereby be selected in view of the pallets transported, such that a pallet may rest securely on the load support members <NUM>, <NUM>. In the present embodiment, the distance is selected such that the opening <NUM> corresponds to approximately <NUM> % the longitudinal length of the pallet, such that one load support member <NUM>, <NUM> is arranged near each opposing longitudinal end of the pallet <NUM>. The distance may further be selected such that the forks of a forklift truck may be received in the opening <NUM> between the load support members <NUM>, <NUM> and engage the underside, e.g. the baseboards, of the pallet <NUM> when resting on the load support members <NUM>, <NUM>. It is possible to arrange three or more load support members <NUM> on the loading surface. An advantage thereof is a more evenly distributed strain on the pallet carried.

To facilitate a loading/unloading operation, the load support members may be yoke-shaped, thus comprising an elongate support portion <NUM> for supporting the underside of a pallet and a central portion <NUM> which extends from the elongate support portion <NUM> to the loading surface <NUM> of the robotic vehicle.

<FIG> shows the robotic vehicle <NUM>' in which a pallet <NUM> is supported onto the elongate support portion <NUM> of the respective load support members <NUM>, <NUM>. Thus, the baseboards <NUM> of the pallet <NUM> thereby rest on the supporting elements <NUM>. In this configuration, the forks of a lift-truck may be received in the transverse pallet channels <NUM> or the longitudinal pallet channels <NUM> of the pallet and thereby engage the pallet. Alternatively, the forks of a lift-truck may be inserted underneath the baseboards <NUM> of the pallet <NUM> in the opening <NUM> between the load support members <NUM>, <NUM> (see <FIG>) and thereby engage the pallet <NUM>. Thereby, a great flexibility in loading/unloading operations is achieved.

<FIG> shows the steps of a transporting operation in which a pallet <NUM> is transported to a loading/unloading station by a robotic vehicle <NUM>' according to the second alternative of the present disclosure. However, the steps described below are also valid for the robotic vehicle <NUM> according to the first alternative of the present disclosure. In <FIG>, the dashed framed drawings show steps B and C without the pallet, for clarity.

As is clear from <FIG>, the loading surface <NUM> comprises one support member opening <NUM> for each load support member <NUM>. The load support members <NUM> are vertically movable with respect to the loading surface <NUM>. The load support members <NUM> are vertically movable from a vertical position in which they are vertically aligned with or below the loading surface <NUM> to a vertical position in which they protrude above the loading surface <NUM> to carry the pallet <NUM>.

Thus, in step A, the robotic vehicle <NUM> arrives at the loading/unloading station <NUM> with a pallet <NUM> supported on the loading surface <NUM>.

In step B, the robotic vehicle <NUM> enters the loading/unloading station <NUM>. Due to the yoke-shaped load support members <NUM>, <NUM>, the robotic vehicle <NUM>' may pass underneath the shelves <NUM> of the loading/unloading station <NUM> while the pallet <NUM> is moved to a position above the shelves <NUM>.

In step C, the robotic vehicle <NUM>' is in a position in which the pallet <NUM> is above the shelves <NUM> and the load support members <NUM>, <NUM> are clear from the shelves <NUM>.

In step D, load support members <NUM>, <NUM> are moved vertically downwards and the pallet <NUM> is placed onto the shelves <NUM> of the loading/unloading station <NUM>.

In step E, the robotic vehicle <NUM>' leaves the loading/unloading station <NUM>.

In step 7B and step 7C, the load support members <NUM>, <NUM> protrude through their respective support member openings. In steps 7A, 7D and 7E, the load support members <NUM>, <NUM> are vertically aligned with the loading surface <NUM>.

A main advantage by the robotic vehicle according to both the first and the second alternative of the present disclosure is that it provides great flexibility in the transporting operation of pallets. Thus, due to that the underside of a pallet on the robotic vehicle is accessible to the forks of a lift-truck it may be removed from the robotic vehicle, or placed onto the robotic vehicle, at any time during the transporting operation. For example, the pallet may be removed from the robotic vehicle before the robotic vehicle arrives at the loading/unloading station. In this context it would be possible to omit the loading/unloading station <NUM>. A further example is when the robotic vehicle <NUM> would malfunction in the loading/unloading station <NUM>. In this situation, a lift truck may remove the pallet <NUM> from the robotic vehicle <NUM>' and transport it to its end station.

<FIG> shows schematically the forks <NUM> of a forklift truck engaging the longitudinal and transverse pallet channels <NUM>, <NUM> of a pallet <NUM> supported on a robotic vehicle <NUM>' according to the second alternative of the present disclosure. However, <FIG> is also valid in view of the robotic vehicle <NUM> of the first alternative of the present disclosure. In that case, the transverse pallet channels <NUM> may be accessed by the forks of the forklift truck.

Claim 1:
A robotic ground conveyor vehicle (<NUM>, <NUM>') for transporting pallets (<NUM>) comprising,
- a loading surface (<NUM>) with;
- a plurality of vertically adjustable load support members (<NUM>, <NUM>) for supporting a pallet carried by the robotic ground conveyor vehicle, wherein the load support members (<NUM>, <NUM>) are arranged spaced apart on the loading surface (<NUM>) and such that a pallet (<NUM>) supported by the load support members (<NUM>, <NUM>) may be engaged by forks (<NUM>) of a forklift truck,
characterised in that the loading surface (<NUM>) extends in a longitudinal direction between a front end (<NUM>) and a rear end (<NUM>) of the robotic ground conveyor vehicle (<NUM>, <NUM>'),
the load support members (<NUM>, <NUM>) are spaced apart at least in the longitudinal direction of the loading surface (<NUM>),
the load support members (<NUM>) are arranged in at least two rows (<NUM>', <NUM>"), wherein each row comprises at least two load support members (<NUM>', <NUM>'; <NUM>", <NUM>"), and wherein the load support members (<NUM>) are spaced apart such that an opening (<NUM>) is formed between at least two adjacent load support members (<NUM>', <NUM>'; <NUM>", <NUM>') of each row (<NUM>', <NUM>"), wherein the opening (<NUM>) is configured to receive a fork (<NUM>) of a forklift truck.