Automated guided vehicle and method of controlling an automated guided vehicle

Abstract

An automated guided vehicle AGV (10a-10e) comprises: a main unit (12) comprising a main body (16) and a plurality of main wheels (20, 84) supporting the main body, at least one of the main wheels being a traction wheel; an auxiliary unit (14) comprising an auxiliary body (24) and at least one auxiliary wheel (26, 86) supporting the auxiliary body; and a hinge (38) connected between the main body and the auxiliary body so that the auxiliary body is rotatable relative to the main body about a horizontal hinge axis (40); wherein the AGV is configured so that, when the main and auxiliary units are supported on a common horizontal surface (22), a centre of mass (68) of the auxiliary unit is horizontally offset from the hinge axis; and wherein the AGV is configured to determine a rotational position (50) of the auxiliary body relative to the main body about the hinge axis.

Description

Technical Field

[0001] This disclosure generally relates to automated guided vehicles (AGVs). In particular, an AGV and a method for controlling the AGV are provided. Background Technology

[0002] Automated Guided Vehicles (AGVs) are typically self-powered and self-driven vehicles. AGVs can be used to transport materials and other items from one location to another without the need for a driver. AGVs may also include manipulators for performing various tasks. AGVs are commonly used in manufacturing sites, warehouses, post offices, libraries, ports, airports, and some hazardous locations and specialized industries.

[0003] EP 2573040 A1 discloses an Automated Guided Vehicle (AGV) for towing a trolley. The AGV includes a first main body, a second main body, drive wheels, and support wheels. The trolley includes casters. The AGV engages with the trolley via a latching mechanism having an adapter plate. The latching mechanism is operated by the movement of the AGV in contact with the trolley or by an electromechanical actuator to secure the trolley and the vehicle together. Summary of the Invention

[0004] In some applications, it is desirable to use AGVs to provide a support surface to support payloads handled by manipulators, such as robotic arms. This requirement may particularly exist when the AGV itself includes manipulators. When the support surface is set on the AGV's main unit, the space and load capacity provided for the payload are typically limited. If the main unit is manufactured to a size for a specific expected payload, the main unit may be too small or too large for payloads beyond the expected payload, resulting in cost-inefficiency.

[0005] To improve the cost-effectiveness and versatility of AGVs, they can be equipped with auxiliary units that are detachably coupled to the main unit, with support surfaces for the payload provided on the auxiliary units. In this way, the space and load capacity provided by the AGV can be increased.

[0006] In EP 2573040 A1, if the trolley is fixed relative to the AGV, the orientation of the trolley relative to the AGV can be known, but the AGV will exhibit poor navigation performance on uneven ground. For example, some wheels may lose contact with the uneven ground. On the other hand, EP 2573040 A1 assumes that some relative motion can exist between the AGV and the trolley. When the trolley travels on an uneven surface, it can tilt relative to the AGV, but the orientation of the trolley relative to the AGV is unknown. For example, this relative motion may occur due to suspension and / or clearance between mechanical components. When the orientation of the AGV's auxiliary units is unknown, it prevents the operator from blindly handling objects on it, i.e., without using methods such as cameras to detect the position of objects one by one.

[0007] One object of the present invention is to provide an improved AGV.

[0008] Another object of the present invention is to provide an improved method for controlling AGVs.

[0009] These objectives are achieved by the AGV according to claim 1 and the method according to claim 8.

[0010] The present invention is based on the understanding that by providing an AGV comprising a main unit and an auxiliary unit connected to the main unit, wherein the auxiliary unit is only capable of rotating relative to the main unit about a horizontal hinge axis, and wherein the AGV is configured to determine the rotational position of the auxiliary unit relative to the main unit about the hinge axis, the AGV provides improved performance and versatility.

[0011] According to a first aspect, an Automated Guided Vehicle (AGV) is provided, the AGV comprising: a main unit including a main body and a plurality of main wheels supporting the main body, at least one of the main wheels being a traction wheel; an auxiliary unit including an auxiliary body and at least one auxiliary wheel supporting the auxiliary body; and a hinge connecting the main body and the auxiliary body such that the auxiliary body can rotate relative to the main body about a horizontal hinge axis; wherein the AGV is configured such that when the main body and the auxiliary unit are supported on a common horizontal surface, the center of mass of the auxiliary unit is horizontally offset from the hinge axis; and wherein the AGV is configured to determine the rotational position of the auxiliary body relative to the main body about the hinge axis.

[0012] The hinge provides a single degree of freedom between the main body and the auxiliary body, namely, rotation about the hinge axis. By determining the rotational position of the auxiliary body, this position can be used as a variable when controlling the manipulator to handle objects carried by the auxiliary body. In this way, any relative rotation between the auxiliary body and the main body about the hinge axis can be compensated online in the computer program used to control the manipulator. When the AGV is stationary, the AGV can determine the rotational position of the auxiliary body.

[0013] AGVs can be designed with low complexity and can be provided at low cost. AGVs employ a modular construction and are easily customized to meet diverse requirements. Auxiliary units can be configured to carry payloads. Because an auxiliary unit includes at least one auxiliary wheel, the payload on the auxiliary unit will be at least partially decoupled from the main unit. That is, at least a portion of the payload (such as the main portion) can be carried by one or more auxiliary wheels. This means that a single main unit can be used for a wide range of applications, and the rating of at least one traction wheel of the main unit can be reduced.

[0014] Furthermore, AGVs offer both improved mechanical performance and improved control performance. Mechanical performance includes the AGV's ability to handle relatively large payloads, for example, larger than the rating of the main unit. Control performance includes the AGV's ability to perform efficient motion on horizontal surfaces and the ability to enable the operator to efficiently handle objects on auxiliary units.

[0015] With the aid of auxiliary units and hinges, the payload on the auxiliary unit can be borne primarily or solely by the auxiliary unit. That is, the main unit is not substantially affected by the payload on the auxiliary unit. The hinge provides a degree of freedom between the main body and the auxiliary body, allowing the AGV to be controlled as a single unit during navigation. Furthermore, the hinge ensures that all wheels of the AGV maintain contact with uneven ground. Additionally, the horizontal offset positioning of the auxiliary unit's center of gravity from the hinge axis ensures that the auxiliary body will rotate around the hinge axis as needed to bring one or more auxiliary wheels into contact with the ground.

[0016] Auxiliary units can be detachably connected to the main unit. In this way, auxiliary units of different sizes and / or types can be connected to the main unit to efficiently scale the area of ​​the support surface and / or the load capacity of the payload. For example, by replacing a relatively small auxiliary unit with a second, relatively large auxiliary unit connected to the main unit, the AGV is scaled to provide a larger support area and load capacity. The possibility of connecting auxiliary units to the main unit enables the modular design of the AGV, where a relatively small number of variations of one or more main units and two or more auxiliary units can meet many different application requirements.

[0017] In an AGV, the center of mass of the auxiliary unit is horizontally offset from the hinge axis. The center of mass of the auxiliary unit can be offset perpendicularly to the hinge axis or not. The center of mass of the auxiliary unit can be considered with or without any effective load on the auxiliary unit. When the main unit is positioned on a horizontal surface, the hinge axis is horizontal. If the main unit is positioned on an inclined surface, the hinge axis may not be horizontal.

[0018] The auxiliary unit may be detachably connected to a hinge, for example. In any case, to provide a detachable connection between the main unit and the auxiliary unit, the AGV may include, for example, a connection interface. The connection interface may be located, for example, between the auxiliary unit and the hinge or between the hinge and the main unit. The connection interface may include a mechanical connection, such as a mechanical connection including one or more fasteners. The connection interface may also optionally include an electrical connection, for example, an electrical connection for powering and controlling one or more traction wheels of the auxiliary unit. If the auxiliary unit does not include any traction wheels, the auxiliary unit may be completely passive. That is, an electrical connection to the auxiliary unit may not be required.

[0019] Although configured to operate in conjunction with auxiliary units, the main unit can also be configured to operate independently without auxiliary units. That is, the main unit can also travel on the surface without auxiliary units. For this purpose, the main unit can include at least three main wheels.

[0020] The main body and auxiliary body can be rigid, for example, made of metal or hard plastic. The hinge can be made of metal or hard plastic, for example. The hinge can include a main hinge component fixed to the main unit and an auxiliary hinge component fixed to the auxiliary unit. The auxiliary hinge component can rotate relative to the main hinge component about the hinge axis.

[0021] The AGV may include an electronic control system configured to determine the rotational position of the auxiliary body. The control system may include at least one data processing device and at least one memory storing at least one computer program, the at least one computer program including program code that, when executed by the at least one data processing device, causes the at least one data processing device to determine the rotational position of the auxiliary body relative to the main body about a hinge axis. The at least one computer program may also include program code that, when executed by the at least one data processing device, causes the at least one data processing device to perform any steps or commands of the AGV described herein.

[0022] The control system can be located in the main unit. The control system can be configured to control the operation of all traction wheels of the AGV to control the movement of the AGV on a horizontal surface.

[0023] Each traction wheel can be controlled to rotate about a horizontal wheel axis to provide propulsion in the forward direction of the traction wheel. Furthermore, each traction wheel can be controlled to rotate about a vertical steering axis to provide steering. For this purpose, the AGV may include a drive motor and a steering motor for each traction wheel.

[0024] At least one auxiliary wheel may include one or more traction wheels and / or one or more driven wheels, such as casters. With all auxiliary wheels positioned horizontally between the centers of mass of the main unit and the auxiliary unit, the auxiliary unit can provide lifting force on the main unit via a hinge. According to one variation, all auxiliary wheels of the auxiliary unit are positioned at the same distance from the hinge axis.

[0025] The hinge axis can be positioned as a line substantially transverse to or transverse to the center of mass of the main unit and the center of mass of the auxiliary unit. It can be assumed that there is no actuator or an actuator at the center of mass of the main unit.

[0026] At least two of the main wheels can be positioned horizontally on the common side of the hinge axis. In some variations, all the main wheels are positioned horizontally on the common side of the hinge axis.

[0027] At least two of the main wheels can be traction wheels. In these cases, the AGV can be configured to perform omnidirectional motion of the main body. Omnidirectional motion is particularly advantageous for AGVs according to the first aspect because the AGV can rotate around an arbitrarily chosen center point, such as the geometric center point of the entire AGV, including the main unit and auxiliary units. This allows the entire AGV to be navigated as a single unit.

[0028] AGVs may also include manipulators supported on the main body. Therefore, an AGV can be an Automated Mobile Robot (AMR) or an Automated Mobile Manipulator Robot (AMMR). The manipulator itself can be a commercially available manipulator.

[0029] When an AGV includes a manipulator, the manipulator can be used to determine the rotational position of the auxiliary body. For example, if the auxiliary body includes an auxiliary support structure of a known shape fixed to it, such as flat, cylindrical, or spherical, the orientation of the auxiliary support structure can be determined by the control system by controlling the manipulator to contact three unique points on the auxiliary support structure and calculating the orientation based on the positions of these points. Based on the orientation of the auxiliary support structure, the control system can determine the rotational position of the auxiliary body.

[0030] As another example, when the manipulator is controlled in through mode, the end effector of the manipulator can be docked to a clamp fixed to an auxiliary support structure. In these ways, the manipulator can be used to measure the relative rotation between the auxiliary body and the main body about the hinge axis.

[0031] The control system can be configured to determine when the manipulator contacts the auxiliary support structure in various ways. In some examples, the control system monitors the current supplied to the actuator of the manipulator to determine when contact occurs. In some examples, the control system monitors one or more forces in the manipulator (e.g., forces determined by one or more force sensors) to determine when contact occurs.

[0032] The auxiliary body may include an auxiliary support structure for supporting the payload. The auxiliary support structure provides a supporting surface for the payload, such as an item to be handled by a manipulator. The auxiliary support structure may be a table.

[0033] The AGV may also include auxiliary sensors arranged to provide rotational data indicating the rotational position of the auxiliary body relative to the main body about a hinge axis. The auxiliary sensors can be configured to transmit the rotational data to a control system. The control system can then determine the rotational position of the auxiliary body based on the rotational data. Auxiliary sensors can be used as an alternative to or supplement to using manipulators to determine the rotational position of the auxiliary body.

[0034] According to a second aspect, a method for controlling an Automated Guided Vehicle (AGV) is provided. The method includes providing an AGV comprising: a main unit including a main body and a plurality of main wheels supporting the main body, at least one of the main wheels being a traction wheel; an auxiliary unit including an auxiliary body and at least one auxiliary wheel supporting the auxiliary body; and a hinge connecting the main body and the auxiliary body such that the auxiliary body can rotate relative to the main body about a horizontal hinge axis; wherein the AGV is configured such that when the main body and the auxiliary unit are supported on a common horizontal surface, the center of mass of the auxiliary unit is horizontally offset from the hinge axis; and the rotational position of the auxiliary body relative to the main body about the hinge axis is determined by the AGV. The AGV in the method described in conjunction with the second aspect can be any type described in conjunction with the first aspect, and vice versa.

[0035] The hinge axis can be positioned as a line that is substantially transverse to or transverse to the centroid of the main unit and the centroid of the auxiliary unit.

[0036] At least two of the main wheels can be positioned horizontally on the common side of the hinge axis.

[0037] At least two of the main wheels can be traction wheels. In these cases, the AGV can be configured to perform omnidirectional movement of the main body.

[0038] AGVs may also include manipulators supported on the main body.

[0039] The auxiliary body may include an auxiliary support structure for bearing the effective load.

[0040] The AGV may also include auxiliary sensors arranged to provide rotational data indicating the rotational position of the auxiliary body relative to the main body about a hinge axis. In these cases, the determination of the rotational position can be based on the rotational data. Attached Figure Description

[0041] Other details, advantages, and aspects of this disclosure will become clear from the following description taken in conjunction with the accompanying drawings, in which:

[0042] Figure 1 : A schematic representation of a side view of an AGV based on an example;

[0043] Figure 2 : Indicative representation Figure 1 A top view of the AGV in the image;

[0044] Figure 3 : Indicative representation Figure 1 and Figure 2 Another side view of the AGV, in which the main body is supported on a horizontal surface and the auxiliary body is supported on an inclined surface;

[0045] Figure 4 : A schematic side view of an AGV and its manipulator outside the AGV, based on another example;

[0046] Figure 5 : A schematic top view of an AGV based on another example;

[0047] Figure 6 : A schematic side view of an AGV based on another example; and

[0048] Figure 7 : A schematic top view of an AGV based on another example. Detailed Implementation

[0049] The following section describes the Automated Guided Vehicle (AGV) and methods for controlling the AGV. The same or similar reference numerals will be used to denote the same or similar structural features.

[0050] Figure 1 A schematic side view of an automated guided vehicle (AGV) 10a is shown. The AGV 10a includes a main unit 12 and an auxiliary unit 14 connected to the main unit 12.

[0051] The main unit 12 includes a body 16. The body 16 includes a main platform 18 disposed at its upper portion. This example of the main unit 12 also includes a plurality of main wheels 20. The main wheels 20 support the body 16 on a horizontal surface 22, such as a floor. This example of the AGV 10a includes four main wheels 20. Figure 1 (Only two are shown in the example). In this example, each main wheel 20 is a traction wheel capable of steering.

[0052] The auxiliary unit 14 includes an auxiliary body 24. In this example, the auxiliary unit 14 includes a single auxiliary wheel 26. The auxiliary wheel 26 supports the auxiliary body 24 on a horizontal surface 22. In this example, the auxiliary wheel 26 is a driven wheel, specifically a caster.

[0053] The auxiliary body 24 in this example includes an auxiliary platform 28 for supporting a payload, illustrated herein as a table. The auxiliary platform 28 is an example of an auxiliary support structure according to this disclosure. Multiple items 30 are placed on the auxiliary platform 28. The items 30 constitute an example of a payload. Figure 1 As shown, the auxiliary platform 28 partially overlaps with the main platform 18. At least when the auxiliary unit 14 is not connected to the main unit 12, one or more items 30 can also be positioned on the main platform 18.

[0054] AGV 10a includes an electronic control system 32. The control system 32 in this example includes a data processing device 34 and a memory 36. The memory 36 stores a computer program. This computer program includes program code that, when executed by the data processing device 34, causes the data processing device 34 to perform the various steps or commands of the AGV 10a described herein. In this example, the control system 32 is housed in the main body 16.

[0055] AGV 10a also includes a hinge 38 connecting the main body 16 and the auxiliary body 24. Hinge 38 is connected here to each of the main body 16 and the auxiliary body 24. Hinge 38 provides a mechanical interface between the main unit 12 and the auxiliary unit 14. Hinge 38 itself can be a commercially available hinge. In this example, all main wheels 20 are positioned horizontally on the common side of hinge 38. Figure 1 (The right side of the middle).

[0056] Hinge 38 defines a horizontal hinge axis 40 about which the main body 16 and the auxiliary body 24 can rotate relative to each other. In this example, this relative rotation is the only degree of freedom between the auxiliary body 24 and the main body 16. The auxiliary platform 28 in this example is horizontal when the entire AGV 10a is positioned on the horizontal surface 22.

[0057] The hinge 38 in this example includes a main hinge component 42 and an auxiliary hinge component 44. The main hinge component 42 is fixed to the body 16, and the auxiliary hinge component 44 is fixed to the auxiliary body 24.

[0058] This example AGV 10a also includes a connection interface 46 for a detachable connection between the main unit 12 and the auxiliary unit 14. In this example, the connection interface 46 is disposed between the auxiliary unit 14 and the hinge 38, and more specifically, between the auxiliary body 24 and the auxiliary hinge component 44. Alternatively, the connection interface 46 is disposed between the hinge 38 and the main unit 12. The connection interface 46 may include fasteners (not shown) to mechanically connect the auxiliary unit 14 to the main unit 12. Since the auxiliary wheel 26 is a driven wheel, and since the auxiliary unit 14 does not require electricity, the connection interface 46 in this example is purely mechanical.

[0059] This example AGV 10a also includes an auxiliary sensor 48. The auxiliary sensor 48 is arranged to provide rotational data indicating the rotational position 50 of the auxiliary body 24 relative to the main body 16 about the hinge axis 40. Therefore, the AGV 10a is arranged to determine the rotational position 50. The auxiliary sensor 48 communicates with the control system 32, and the rotational data from the auxiliary sensor 48 is sent to the control system 32. In this example, the auxiliary sensor 48 is integrated into the hinge 38.

[0060] The AGV 10a in this example also includes a manipulator 52a, illustrated here as a serial robotic arm that can be programmed on three or more axes, such as six or seven axes. AGV 10a is therefore an Automated Mobile Manipulator Robot (AMMR). Figure 1 The AGV coordinate system 54 is further illustrated. The manipulator 52a is controlled by the control system 32. The manipulator 52a can be controlled within the AGV coordinate system 54 to perform various tasks. The control system 32 also controls the drive of the main wheel 20. Furthermore, the control system 32 tracks the position of the AGV 10a in the global coordinate system 56 in a known manner, such as using odometers, triangulation, and / or lidar (light detection and ranging).

[0061] Manipulator 52a is supported on body 16, which is supported on its main platform 18. Manipulator 52a includes a plurality of joints 58 (one per axis) and actuators 60 located at each joint 58 for driving the respective joint 58. Each joint 58 may be rotational or translational. The manipulator 52a of this example also includes end effectors 62, illustrated here as clamps.

[0062] The manipulator 52a in this example also includes an encoder 64 and a force sensor 66 located at each joint 58. Each encoder 64 is arranged to determine the position of the associated joint 58, and the force sensor 66 is arranged to sense the force in the manipulator 52a. The corresponding data is sent to the control system 32.

[0063] Figure 1 The center of mass 68 of the auxiliary unit 14 and the center of mass 70 of the main unit 12 are further illustrated. In this example, the center of mass 68 of the auxiliary unit 14 is determined without any payload on it, while the center of mass 70 of the main unit 12 is determined with the manipulator 52a on it. That is, the center of mass 70 of the main unit 12 represents the combined center of mass 70 of the main unit 12 and the manipulator 52a. Figure 1 As shown, when AGV 10a is supported on horizontal surface 22, the center of mass 68 of auxiliary unit 14 is horizontally offset from hinge axis 40. Furthermore, Figure 1 As shown, the hinge axis 40 is positioned transversely to line 72 between the centers of mass 68 and 70.

[0064] In some applications, the AGV 10a may require a smaller footprint. In this case, the AGV 10a can operate only with the main unit 12, that is, without the auxiliary unit 14. In other applications, the AGV 10a may need to carry heavy loads, such as exceeding 150 kg, on a larger support structure. In this case, the AGV 10a can operate together with the auxiliary unit 14 to meet the load requirements. Therefore, the AGV 10a has a modular and versatile design.

[0065] The horizontal distance between the auxiliary wheel 26 and the hinge axis 40 will determine how the load on the auxiliary unit 14 affects the main unit 12. If the center of mass 68 of the auxiliary unit 14 is horizontally positioned between the auxiliary wheel 26 and the hinge axis 40, such as Figure 1 As shown, the auxiliary unit 14 will provide a downward force on the main wheel 20 closest to the hinge axis 40. On the other hand, if the auxiliary wheel 26 is positioned between the center of mass 68 of the auxiliary unit 14 and the hinge axis 40, the auxiliary unit 14 will provide an upward force on the main wheel 20 closest to the hinge axis 40.

[0066] Manipulator 52a can handle each item 30 on auxiliary platform 28, for example, by picking up item 30 from auxiliary platform 28, placing item 30 on auxiliary platform 28, or performing operations on item 30 while it is positioned on auxiliary platform 28. When AGV 10a is stationary, handling of item 30 by manipulator 52a on auxiliary platform 28 can be performed. For manipulator 52a to pick up, place, or otherwise handle item 30 on auxiliary platform 28, control system 32 must know the position of each item 30 in AGV coordinate system 54. AGV 10a can determine these positions based on rotational position 50.

[0067] Different applications may impose different requirements on the size and payload capacity of the AGV 10a. Since the auxiliary unit 14 can be replaced with different types of auxiliary units 14 (e.g., for handling larger payloads), the AGV 10a can be upgraded to efficiently address this issue while requiring a minimum number of different types of main units 12 and auxiliary units 14. End users can, for example, provide combinations of the AGV 10a and different auxiliary units 14, and select one of the auxiliary units 14 for connection to the main unit 12 based on the task to be performed by the AGV 10a. A single auxiliary unit 14 can also be used with different types of main units 12.

[0068] Since AGV 10a can also carry payloads on the main platform 18, it can be used without auxiliary unit 14 for small and light payloads, while it can be used with auxiliary unit 14 for larger and / or heavier payloads. In this way, the size of the main wheel 20 does not require AGV 10a to carry heavy payloads without auxiliary unit 14. This significantly improves the cost efficiency of AGV 10a.

[0069] Figure 2 A schematic top view of AGV 10a. (e.g.) Figure 2 As shown, the AGV 10a in this example includes two concentric hinges 38. Therefore, the AGV 10a may include one or more concentric hinges 38. Each hinge 38 is connected between the main body 16 and the auxiliary body 24, such that the auxiliary body 24 can rotate relative to the main body 16 about the hinge axis 40. For the purposes of this application, only one hinge 38 needs to be described.

[0070] In this example, each main wheel 20 includes a drive motor (not shown) for driving the main wheel 20 to rotate about a horizontal wheel axis 74, such that the main wheel 20 is driven in the forward direction 76. In this example, each main wheel 20 also includes a steering motor (not shown) for driving the main wheel 20 to rotate about a vertical steering axis 78.

[0071] Due to the configuration of the main wheels 20, the entire AGV 10a, including both the main unit 12 and the auxiliary unit 14, can perform omnidirectional motion on the horizontal surface 22 as a single unit. The AGV 10a can be driven instantly in any horizontal direction, for example, and can rotate on-site, such as around the geometric center point of the entire AGV 10a. The omnidirectional motion of the AGV 10a can be achieved by using Swedish wheels.

[0072] In addition, from Figure 2 As can be seen, when the auxiliary unit 14 is disconnected from the main unit 12, the four main wheels 20 of the main unit 12 still enable the main unit 12 to move on the horizontal surface 22. Therefore, the main unit 12 is independent and stable.

[0073] Figure 3 This schematically illustrates another side view of the AGV 10a. Figure 3 In the middle, AGV 10a is stationary, while the main body 16 is supported on the horizontal surface 22, and the auxiliary body 24 is supported on the inclined surface 80.

[0074] For various reasons, the auxiliary body 24 can rotate relative to the main body 16 about the hinge axis 40. One reason for this rotation is that the AGV 10a is positioned on uneven ground. Another reason for this rotation is the non-rigid nature of the suspension of the main wheel 20 and the auxiliary wheel 26 and their tires. Yet another reason for this rotation could be the current load distribution on the AGV 10a, which could include the payload on the manipulator 52a and the auxiliary platform 28.

[0075] Picking up and placing items 30 on the auxiliary platform 28 may require sub-millimeter precision from the manipulator 52a. By knowing the rotational position 50 of the auxiliary body 24 relative to the main body 16 about the hinge axis 40, even if the AGV 10a is stopped on uneven ground, causing a relative tilt between the auxiliary body 24 and the main body 16, the manipulator 52a can blindly handle items 30 on the auxiliary platform 28. Therefore, more efficient operation of the AGV 10a is possible.

[0076] The position of hinge axis 40 in the AGV coordinate system 54 is known to the control system 32, for example, through measurement. Furthermore, the geometric relationship between hinge axis 40 and the auxiliary platform 28 currently connected to the main unit 12 is also known to the control system 32, for example, through measurement. Based on the position of hinge axis 40 in the AGV coordinate system 54, the geometric relationship between hinge axis 40 and the auxiliary platform 28, and the rotational position 50 of the auxiliary body 24 relative to the main body 16 about hinge axis 40, the control system 32 calculates the position and orientation of the auxiliary platform 28 in the AGV coordinate system 54. The control system 32 can thus update the position of the item 30 on the auxiliary platform 28 in the AGV coordinate system 54.

[0077] As an alternative or supplement to using auxiliary sensor 48 to determine rotational position 50, manipulator 52a can be used. Figure 3 In this example, manipulator 52a can be controlled to bring end effector 62 into contact with three unique and non-collinear points on auxiliary platform 28. Since auxiliary platform 28 in this example comprises a flat support surface, control system 32 can calculate the orientation of auxiliary platform 28 in AGV coordinate system 54 based on these three unique points. Signals from encoder 64 and / or from force sensor 66 can be used by control system 32 to determine when end effector 62 contacts auxiliary platform 28.

[0078] Figure 4A schematic side view of AGV 10b according to another example is shown. The main differences from AGV 10a will be described. AGV 10b is an Automated Mobile Robot (AMR) without a manipulator. Furthermore, the auxiliary wheel 26 is positioned here between the center of mass 68 of the auxiliary unit 14 and the hinge axis 40. Therefore, in this example, the auxiliary unit 14 provides an upward force on the main wheel 20 closest to the hinge axis 40. In this example, the connection interface 46 is arranged between the main hinge component 42 and the body 16.

[0079] Figure 4 The industrial robot 82, including manipulator 52b, is further illustrated. Manipulator 52b is an external manipulator that does not move with AGV 10b. Since AGV 10b can determine the position and orientation of the auxiliary platform 28 and the items 30 thereon in AGV coordinate system 54, and since AGV 10b knows its position in global coordinate system 56, the position and orientation of the auxiliary platform 28 and the items 20 thereon can be determined by AGV coordinate system 54 in global coordinate system 56, and this information can be transmitted to industrial robot 82. Therefore, even if the auxiliary body 24 rotates relative to the main body 16, manipulator 52b can be controlled to blindly handle the items 30 on the auxiliary platform 28.

[0080] Figure 5 A schematic top view of AGV 10c according to another example is shown. The main differences from AGV 10a will be described. Also in AGV 10c, the main unit 12 includes four main wheels, and the auxiliary unit 14 includes two auxiliary wheels. However, here the main wheels consist of two driven main wheels 20 and two passive main wheels 84, and the auxiliary wheels consist of two passive auxiliary wheels 86. Each passive main wheel 84 can be of the same type as the auxiliary wheel 26. Each auxiliary wheel 86 can be of the same type as the main wheel 20. Since the auxiliary wheels 86 are drive wheels controlled by the control system 32, the connection interface 46 in this example is both mechanical and electrical. Figure 5 In the middle, the two auxiliary wheels 86 are located at the same distance from the hinge axis 40.

[0081] like Figure 5 As shown, each pair of auxiliary wheels 86, driven main wheels 84, and driven main wheels 20 are located on corresponding lines parallel to the hinge axis 40. The driven main wheel 84 is horizontally positioned between the auxiliary wheels 86 and the driven main wheels 20. This wheel configuration improves the maneuverability of the AGV10c.

[0082] Figure 6A schematic side view of an AGV 10d according to another example is shown. The main differences from AGV 10a will be described. In AGV 10d, the center of mass 68 of the auxiliary wheel 26 and the auxiliary unit 14 is horizontally positioned between the hinge 38 and the body 16. In this example, each of the main hinge component 42 and the auxiliary hinge component 44 is implemented as an elongated rod. When AGV 10d is positioned on the horizontal surface 22, the main hinge component 42 extends horizontally between the body 16 and the hinge 38, and the auxiliary hinge component 44 extends vertically between the hinge 38 and the auxiliary platform 28. A connection interface 46 is arranged here between the auxiliary hinge component 44 and the auxiliary platform 28.

[0083] Furthermore, the AGV 10d in this example includes a fixture 88 on the auxiliary platform 28. By engaging the end effector 62 into the fixture 88 and controlling the manipulator 52a in a conducting mode, wherein the manipulator 52a is flexible, the position and orientation of the end effector 62, known to the control system 32, will correspond to the position and orientation of the auxiliary platform 28 as the auxiliary body 24 rotates relative to the main body 16 about the hinge 38. In the same way, the rotational position 50 can be determined.

[0084] Figure 7 A schematic top view of AGV 10e according to another example is shown. The main differences from AGV 10a will be described. Figure 7 In the middle, hinge 38 is positioned on one side of the body 16, such that hinge axis 40 is oriented to be substantially parallel to line 72 between the centers of mass 68 and 70.

[0085] While this disclosure has been described with reference to exemplary embodiments, it should be understood that the invention is not limited to the foregoing. For example, it should be understood that the dimensions of the components can be varied as needed. Therefore, the invention is limited only by the scope of the appended claims.

Claims

1. An automated guided vehicle (AGV) (10a-10e), comprising: - The main unit (12) includes a main body (16) and a plurality of main wheels (20, 84) supporting the main body (16), at least one of the main wheels (20, 84) being a traction wheel (20). - An auxiliary unit (14) includes an auxiliary body (24) and at least one auxiliary wheel (26, 86) supporting the auxiliary body (24); and - A hinge (38) connects the main body (16) and the auxiliary body (24) such that the auxiliary body (24) can rotate relative to the main body (16) about a horizontal hinge axis (40); The AGVs (10a-10e) are configured such that when the main body (16) and the auxiliary unit (14) are supported on a common horizontal surface (22), the center of mass (68) of the auxiliary unit (14) is horizontally offset from the hinge axis (40); and The AGV (10a-10e) is configured to determine the rotational position (50) of the auxiliary body (24) relative to the main body (16) about the hinge axis (40).

2. The AGV (10a-10d) according to claim 1, wherein the hinge axis (40) is positioned substantially transversely to a line (72) between the centroid (70) of the main unit (12) and the centroid (68) of the auxiliary unit (14).

3. The AGV (10a-10e) according to any one of the preceding claims, wherein at least two of the main wheels (20, 84) are horizontally positioned on the common side of the hinge axis (40).

4. The AGV (10a-10e) according to any one of the preceding claims, wherein at least two of the main wheels (20, 84) are traction wheels (20); and wherein the AGV (10a-10e) is configured to perform omnidirectional movement of the body (16).

5. The AGV (10a-10e) according to any one of the preceding claims further includes a manipulator (52a) supported on the body (16).

6. The AGV (10a-10e) according to any one of the preceding claims, wherein the auxiliary body (24) includes an auxiliary support structure (28) for carrying the payload (30).

7. The AGV (10a-10e) according to any one of the preceding claims further includes an auxiliary sensor (48) arranged to provide rotational data indicating the rotational position (50) of the auxiliary body (24) relative to the main body (16) about the hinge axis (40).

8. A method for controlling an Automated Guided Vehicle (AGV) (10a-10e), the method comprising: - Provide an AGV (10a-10e) comprising: a main unit (12) including a body (16) and a plurality of main wheels (20, 84) supporting the body (16), at least one of the main wheels (20, 84) being a traction wheel (20); an auxiliary unit (14) including an auxiliary body (24) and at least one auxiliary wheel (26, 86) supporting the auxiliary body (24); and a hinge (38) connecting the body (16) and the auxiliary body (24) such that the auxiliary body (24) is rotatable relative to the body (16) about a horizontal hinge axis (40); wherein the AGV (10a-10e) is configured such that when the body (16) and the auxiliary unit (14) are supported on a common horizontal surface (22), the center of mass (68) of the auxiliary unit (14) is horizontally offset from the hinge axis (40); and - The rotational position (50) of the auxiliary body (24) relative to the main body (16) about the hinge axis (40) is determined by the AGV (10a-10e).

9. The method according to claim 8, wherein the hinge axis (40) is positioned substantially transversely to a line (72) between the centroid (70) of the main unit (12) and the centroid (68) of the auxiliary unit (14).

10. The method according to claim 8 or 9, wherein at least two of the main wheels (20, 84) are horizontally positioned on the common side of the hinge axis (40).

11. The method according to any one of claims 8 to 10, wherein at least two of the main wheels (20, 84) are traction wheels (20); and wherein the AGV (10a-10e) is configured to perform omnidirectional movement of the body (16).

12. The method according to any one of claims 8 to 11, wherein the AGV (10a-10e) further comprises a manipulator (52a) supported on the body (16).

13. The method according to any one of claims 8 to 12, wherein the auxiliary body (24) comprises an auxiliary support structure (28) for bearing the effective load (30).

14. The method according to any one of claims 8 to 13, wherein the AGV (10a-10e) further comprises an auxiliary sensor (48) arranged to provide rotational data indicating the rotational position (50) of the auxiliary body (24) relative to the main body (16) about the hinge axis (40), and wherein the determination of the rotational position (50) is based on the rotational data.

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