Method and system for determining belt slippage

Abstract

A method and system for determining drive belt slippage is disclosed that uses two motors to determine drive belt slippage.

Description

Technical Field

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[0001] The present invention relates to a method and a system for determining slippage in a drive belt as used in a load handling device.

Background Art

[0002] In commercial and industrial activities, there is a need for systems that enable the storage and retrieval of a number of different products. WO2015 / 185628A describes a storage and fulfillment system in which stacks of storage containers are arranged within a grid storage structure. The containers are accessed from above by a load handling device operable on rails or tracks located at the top of the grid storage structure. The load handling device is further described in WO2015 / 019055A1. >

[0003] In a storage and fulfillment system, it is important that the load handling device operates optimally. In particular, the drive belt used in the load handling device should operate under optimal tension. The present invention has been devised in view of this background.

Summary of the Invention

[0004] In a first aspect, a system for determining slippage of a drive belt, the system comprising: a drive belt; a first and a second motor configured to drive the drive belt; a controller wherein the controller is configured to receive first and second transient currents from the first and second motors respectively during simultaneous startup of the first and second motors for driving the drive belt; determine slippage of the drive belt when the first and second current values of the first and second transient currents differ by at least a threshold value substantially simultaneously; A system exists that is configured to perform this task. This means that the system can use only existing system components to determine drive belt slippage, and no external hardware is required to determine drive belt slippage.

[0005] The threshold can be defined by the minimum percentage difference between a first current value and a second current value, and / or the minimum amperage difference between the first current value and the second current value. This ensures that noise during transient currents is not judged as belt slippage.

[0006] A cargo handling device for lifting and moving storage containers stacked within a grid framework structure, wherein the grid framework structure is The system comprises a first set of parallel rails or tracks and a second set of parallel rails or tracks extending substantially perpendicular to the first set of parallel rails or tracks in a substantially horizontal plane to form a grid pattern comprising multiple grid spaces, wherein the grid is supported by sets of upright members to form multiple vertical storage locations directly beneath the grid, such that containers are stacked vertically between sets of upright members and guided by sets of upright members through multiple grid spaces, and the cargo handling device is A body or skeleton mounted on a first set of wheels arranged to engage with a first set of parallel tracks, and a second set of wheels arranged to engage with a second set of parallel tracks, A drive assembly comprising the first system described in the above embodiment, wherein the drive belt and first and second motors of the first system are configured to drive a first or second set of wheels to move a load handling device along a first or second set of parallel rails, and the controller of the first system is configured to receive first and second transient currents from the first and second motors of the first system while the first or second set of wheels are being driven, and / or A reversible assembly comprising the second system described in the above embodiment, wherein the drive belt and first and second motors of the second system are configured to raise or lower a first set of wheels and / or lower or raise a second set of wheels relative to the body or skeleton in order to engage and disengage the wheels with parallel tracks, and the controller of the second system is configured to receive first and second transient currents from the first and second motors of the second system, respectively, during the raising or lowering of the first set of wheels and / or the lowering or raising of the second set of wheels, and / or A container lifting assembly comprising the third system described in the above embodiment, wherein the drive belt and first and second motors of the third system are configured to raise or lower a gripping device in the vertical direction, and the controller of the third system is configured to receive first and second transient currents from the first and second motors of the third system, respectively, during the raising or lowering of the gripping device. A cargo handling device exists that is equipped with this feature. This means that slippage in the drive belt of the cargo handling device can be detected.

[0007] The steering assembly may be configured to raise or lower a first set of wheels and to synchronously lower or raise a second set of wheels relative to the body. This means that slippage during steering can be detected.

[0008] The steering assembly may have at least one steering mechanism for either a first or second set of wheels, or for each of the first and second sets of wheels. The steering assembly may have two steering mechanisms for each of the first and second sets of wheels. The steering mechanisms may be driven by a drive belt of the second system. This means that slippage may be correlated to a particular operation of the steering mechanism.

[0009] The first and second motors may be mounted in opposing or adjacent locations within the cargo handling device. Opposing or adjacent locations may include corners of the cargo handling device. Opposing or adjacent locations or corners may be on the body or skeleton. The drive belt may substantially encircle the skeleton or body of the cargo handling device. This means that the motors may be positioned to distribute torque loads between them.

[0010] The system may further include an automatic tensioning device, and the controller may be further configured to control the automatic tensioning device to increase the tension of the drive belt when it determines that slippage has occurred in the drive belt, and / or decrease the tension of the drive belt when it determines that slippage has not occurred in the drive belt.

[0011] This means that the system can prevent the drive belt from slipping during subsequent operations and / or optimize the efficiency of the drive belt.

[0012] In a second aspect, a method for determining slippage of a drive belt in a system, wherein the system comprises the system described in the above aspect, and the method uses a controller. During the simultaneous startup of the first and second motors for driving the drive belt, the system receives first and second transient currents from the first and second motors, respectively. If the current values ​​of the first and second transient currents differ substantially simultaneously by at least a threshold amount, it is determined that slippage of the drive belt has occurred. There is a method that provides this.

[0013] In a third aspect, there exists a computer program comprising instructions, the instructions causing the computer to perform the method described in the second aspect when the computer program is executed by the computer.

[0014] In a fourth aspect, there is a data processing system comprising a processor configured to implement the method described in the second aspect.

[0015] The present invention is described with reference to one or more exemplary embodiments as illustrated in the accompanying drawings.

Brief Description of the Drawings

[0016] [Figure 1] Shows a storage structure and a container. [Figure 2] Shows a rail or track on top of the storage structure illustrated in FIG. 1. [Figure 3] Shows a cargo handling device on top of the storage structure illustrated in FIG. 1. [Figure 4] Shows a single cargo handling device in which the container lifting means is in a lowered configuration. [Figure 5A] Shows a cutaway view of a single cargo handling device in which the container lifting means is in a raised configuration. [Figure 5B] Shows a cutaway view of a single cargo handling device in which the container lifting means is in a lowered configuration. [Figure 6] Is a schematic view of a cargo handling device having a steering mechanism. [Figure 7] Is a schematic view of a compliant mechanism for use when engaging first and second sets of wheels of a cargo handling device as part of a steering assembly. <​​​​​​​ [Figure 10b] A schematic view of a linkage set for use when engaging with the first and second sets of wheels of a load handling device as part of a steering assembly. [Figure 10c] A schematic view of a linkage set for use when engaging with the first and second sets of wheels of a load handling device as part of a steering assembly. [Figure 11] Shows a cam mechanism for use when engaging with the first and second sets of wheels of a load handling device as part of a steering assembly. [Figure 12] Shows a double cam mechanism for use when engaging with the first and second sets of wheels of a load handling device as part of a steering assembly. [Figure 13] Shows a double cam mechanism for use when engaging with the first and second sets of wheels of a load handling device as part of a steering assembly. [Figure 14] Shows an exemplary drive assembly used in a load handling device. [Figure 15] Shows an exemplary container lifting assembly. <00OO108>Shows a system according to an embodiment. [Figure 17] Shows a method for determining slippage of a drive belt within a system according to an embodiment. [Figure 18] Shows first and second transient currents according to an embodiment. [Figure 19] Shows first and second transient currents according to an embodiment.

MODE FOR CARRYING OUT THE INVENTION

[0017] Online retailers, such as online grocery stores and supermarkets, that sell multiple product lines require systems capable of storing tens or hundreds of thousands of different product lines. Using single-product stacks in such cases can be impractical, as it would require vast floor space to accommodate all the necessary stacks. Furthermore, the need to store small quantities of a few items, such as perishable goods or infrequently ordered items, makes single-product stacks an inefficient solution.

[0018] International patent application WO98 / 049075A (Autostore), the contents of which are incorporated herein by reference, describes a system in which a multi-product stack of containers is arranged within a frame structure.

[0019] PCT Publication No. WO2015 / 185628A (Ocado) describes a more known storage and fulfillment system in which container stacks are arranged within a grid framework structure. The containers are accessed by one or more loading / unloading devices, also known as "bots," which are operable on tracks located at the top of the grid framework structure. This type of system is schematically illustrated in Figures 1-3 of the attached drawings.

[0020] As shown in Figures 1 and 2, stackable containers 10, also known as “containers” or “totes,” are stacked on top of each other to form a stack 12. The stack 12 is placed, for example, in a grid framework structure 14 in a warehouse or manufacturing environment. The grid framework structure 14 consists of a plurality of storage columns or grid columns. Each grid in the grid framework structure has at least one grid column for storing the stack of containers. Figure 1 is a schematic perspective view of the grid framework structure 14, and Figure 2 is a schematic top view showing the stack 12 of containers 10 placed within the framework structure 14. Each container 10 typically holds multiple product items (not shown). The product items in the container 10 may be the same or different product types depending on the application.

[0021] The grid framework structure 14 comprises a plurality of upright members 16 supporting horizontal members 18, 20. A first set 18 of parallel horizontal grid members is positioned perpendicular to a second set 20 of parallel horizontal members in a grid pattern so as to form a horizontal grid structure 15 supported by the upright members 16. The members 16, 18, 20 are typically manufactured from metal. The containers 10 are stacked between the members 16, 18, 20 of the grid framework structure 14, so that the grid framework structure 14 prevents horizontal movement of the stack 12 of containers 10 and guides the vertical movement of the containers 10.

[0022] The top level of the grid framework structure 14 comprises a grid or grid structure 15 including rails 22 arranged in a grid pattern across the tops of the stacks 12. Referring to Figure 3, the rails or tracks 22 guide a plurality of load handling devices 30. A first set 22a of parallel rails 22 guides the movement of the robotic load handling devices 30 in a first direction (e.g., the X direction) across the tops of the grid framework structure 14. A second set 22b of parallel rails 22, positioned perpendicular to the first set 22a, guides the movement of the load handling devices 30 in a second direction (e.g., the Y direction) perpendicular to the first direction. In this way, the rails 22 allow the robotic load handling devices 30 to move laterally in two dimensions within the horizontal XY plane. The load handling devices 30 can be moved to a position above any of the stacks 12.

[0023] Known forms of the load handling device 30 shown in Figures 4, 5A, and 5B are described in PCT Patent Publication WO2015 / 019055 (Ocado), incorporated herein by reference, where each load handling device 30 covers a single grid space 17 of the grid framework structure 14. This configuration allows for a higher density of load handlers, thereby enabling higher throughput for a system of a given size.

[0024] The cargo handling device 30 comprises a vehicle 32 positioned to move on rails 22 of a frame structure 14. A first set of wheels 34, consisting of a pair of wheels 34 on the front of the vehicle 32 and a pair of wheels 34 on the rear of the vehicle 32, is positioned to engage with two adjacent rails of the first set 22a of rails 22. Similarly, a second set of wheels 36, consisting of a pair of wheels 36 on each side of the vehicle 32, is positioned to engage with two adjacent rails of the second set 22b of rails 22. Each set of wheels 34, 36 can be raised and lowered by a reversal assembly so that either the first set of wheels 34 or the second set of wheels 36 engages with the respective sets 22a, 22b of rails at any given time (examples are shown in Figures 6-13). For example, when a first set of wheels 34 engages with a first set of rails 22a and a second set of wheels 36 is lifted away from the rails 22, the first set of wheels 34 may be driven by a drive mechanism housed in the vehicle 32 to move the load handling device 30 in the Y direction (an example of which is shown in Figure 10b). To achieve movement in the X direction, the first set of wheels 34 is lifted away from the rails 22 and the second set of wheels 36 is lowered to engage with a second set of rails 22b. The drive assembly may then be used to drive the second set of wheels 36 to move the load handling device 30 in the X direction.

[0025] The cargo handling device 30 is equipped with a container lifting device or assembly, such as a crane mechanism, for lifting storage containers from above. The lifting device comprises a winch tether or cable 38 wound on a spool or reel and a gripper device 39. The lifting device shown in Figure 4 (further examples are shown in Figure 15) comprises a set of four vertically extending lifting tethers 38. The tethers 38 are connected to the gripper device 39, for example, at or near each of the four corners of the lifting frame, for a releasable connection to the storage container 10. For example, each tether 38 is located at or near each of the four corners of the lifting frame. The gripper device 39 is configured to releasably grip the top of the storage container 10 and lift the storage container 10 from a stack of containers in the type of storage system shown in Figures 1 and 2. For example, the lifting frame 39 may include a pin (not shown) that engages with a corresponding hole (not shown) in a rim forming the top surface of the container 10, and a slide clip (not shown) that can engage with the rim to grip the container 10. The clip is driven to engage with the container 10 by a suitable drive mechanism housed within the lifting frame 39, which is powered and controlled by signals transmitted through the cable 38 itself or a separate control cable (not shown).

[0026] To retrieve the container 10 from the top of the stack 12, the loading handling device 30 is first moved in the X and Y directions so that the gripper device 39 is positioned above the stack 12. The gripper device 39 is then lowered vertically in the Z direction, as shown in Figures 4 and 5B, to engage with the container 10 on top of the stack 12. The gripper device 39 grasps the container 10 and is then pulled upward by the cable 38 with the container 10 attached. At the top of its vertical movement, the container 10 is held above the rails 22 housed within the vehicle body 32. In this way, the loading handling device 30 can be moved to different positions in the XY plane, carrying the container 10 with it, and transporting the container 10 to another location. Upon reaching the target location (e.g., another stack 12, an access point in a storage system, or a belt conveyor), the container 10 can be lowered from the container receiving section and released from the grabber device 39. The cable 38 is long enough to allow the cargo handling device 30 to take out and place containers from any level of the stack 12, including, for example, floor level.

[0027] As shown in Figure 3, multiple identical cargo handling devices 30 are provided so that each cargo handling device 30 can operate simultaneously to increase the system throughput. The system illustrated in Figure 3 may include specific locations known as ports, where containers 10 can be transported in or out of the system. Additional conveyor systems (not shown) may be associated with each port so that containers 10 transported to a port by a cargo handling device 30 can be transported by the conveyor system to another location, such as a picking station (not shown). Similarly, containers 10 can be moved by the conveyor system from an external location to a port, for example, a container filling station (not shown), and then transported by a cargo handling device 30 to a stack 12 to replenish the stock in the system.

[0028] Each cargo handling device 30 can lift and move one container 10 at a time. The cargo handling device 30 has a container receiving cavity or recess 40 at its bottom. The recess 40 is sized to accommodate the container 10 when lifted by the lifting mechanism, as shown in Figures 5A and 5B. When in the recess, the container 10 is lifted away from the rail 22 directly below, so that the vehicle 32 can move laterally to different locations.

[0029] If it is necessary to retrieve a container 10b ("target container") that is not located at the top of stack 12, the containers 10a ("non-target containers") above it must first be moved in order to allow access to the target container 10b. This is achieved by an operation hereafter referred to as "digging." Referring to Figure 3, during the digging operation, one of the cargo handling devices 30 sequentially lifts each non-target container 10a from the stack 12 containing the target container 10b and places it in an empty position in another stack 12. The target container 10b can then be accessed by the cargo handling device 30 and moved to a port for further transport.

[0030] Each of the provided cargo handling devices 30 is remotely operated under the control of a central computer. Each individual container 10 in the system is also tracked so that the appropriate container 10 can be retrieved, transported, and replaced as needed. For example, during the digging operation, each non-target container location is logged so that non-target containers 10a can be tracked.

[0031] Wireless communication and networks may be used to provide a communication infrastructure from a master controller to one or more load handling devices that can operate on the grid structure, for example, via one or more base stations. In response to receiving commands from the master controller, controllers in the load handling devices are configured to control various drive mechanisms to control the movement of the load handling devices. For example, a load handling device may be commanded to retrieve a container from a target storage column at a specific location on the grid structure. This command may include various movements in the XY plane of the grid structure 15. As previously described, upon reaching the target storage column, the lifting mechanism may be operated to grasp and lift the storage container 10. Once the container 10 is housed in the container receiving space 40 of the load handling device 30, the container 10 is then transported to another location on the grid structure 15, for example, a “drop-off port”. At the drop-off port, the container 10 is lowered to a suitable picking station to allow retrieval of any items in the storage container. The movement of the cargo handling device 30 on the grid structure 15 may also involve the cargo handling device 30 being commanded to move to a charging station that is normally located around the grid structure 15.

[0032] To move the cargo handling devices 30 on the grid structure 15, each of the cargo handling devices 30 is equipped with a motor to drive wheels 34, 36. The wheels 34, 36 may be driven via one or more belts connected to the wheels, or individually driven by motors integrated into the wheels. In the case of a single-cell cargo handling device (where the installation area of ​​the cargo handling device 30 occupies a single grid cell 17), the motors for driving the wheels may be integrated into the wheels due to the limited availability of space within the vehicle body. For example, the wheels of a single-cell cargo handling device are driven by their respective hub motors. Each hub motor comprises an external rotor having multiple permanent magnets arranged to rotate around a wheel hub, which has coils forming an internal stator.

[0033] The system described with reference to Figures 1-5 has many advantages and is suitable for a wide range of storage and retrieval operations. In particular, it provides a very economical way to store a wide range of different items in container 10, while also allowing for very high-density storage of products and reasonably economical access to all of container 10 when needed for picking.

[0034] An exemplary reversal assembly is shown in Figure 6, in which the first and second sets of wheels 34, 36 can be raised away from the rails or lowered onto the rails. The reversal assembly comprises a compliant mechanism(s) 110 (or linkage set 300 shown in Figures 9 and 10, or cam mechanisms 120, 130 as shown in Figures 11-13) located on the opposing surface of the body or skeleton 102 of the load handling device.

[0035] Each of the direction-changing compliant mechanisms 110 (further described in PCT Publication No. WO2021175922A1 (Ocado)) is deformable in a first and a second direction. Figure 7 illustrates the compliant mechanism 110 in three positions, below which the positions of the wheels 34, 36 relative to the body or skeleton 102 and rails in each of those positions are illustrated. Figure 8 is a perspective view of the load handling device showing the positions of the compliant mechanism 110 (or linkage set 300, or cam mechanisms 120, 130) and wheels in positions similar to those shown in Figure 7.

[0036] When there is no input force, the compliant mechanism 110 is stationary or in a neutral position; that is, the compliant mechanism 110 is not elastically deformed, and both sets of wheels 34, 36 are horizontal and stationary on the surface. In this configuration, the load handling device is not capable of moving in the x or y direction, and the load handling device is stationary (Figures 7a and 8a). The elastic deformation of the compliant mechanism 110 is linked to an arm that holds each of the wheels and is movable in the vertical (i.e., z) direction to raise and lower the wheels.

[0037] When a first input force F1 is applied, the body of the compliant mechanism 110 deforms in a first direction. The displacement of the mechanism body is converted vertically, causing the first set of wheels 34 to rise and the second set of wheels 36 to descend. As shown in Figures 7c and 8c, the wheels of the first set of wheels 34 move upward so as to move away from the rails, and the wheels of the second set of wheels 36 move downward so as to engage with the rails and support the vehicle. Thus, the vehicle 30 can be driven in the x direction.

[0038] When a second input force F2 is applied in the opposite direction to the first input force, the body of the compliant mechanism 110 deforms in the second direction. The displacement of the mechanism body is converted to act vertically, causing the first set of wheels 34 to descend and the second set of wheels 36 to rise, so that the load handling device can be supported by the first set of wheels 34 and driven in the y direction (Figures 7b and 8b).

[0039] The compliant mechanism 110 is connected to the wheel sets 34, 36 via a transmission linkage. Thus, the compliant mechanism 110 (or the linkage set 300 or the cams 120, 130) provides a means for changing the direction of movement of the load handling device 30.

[0040] The compliant mechanism 110 illustrated in Figures 7a-c will be recognized as comprising a series of column or trunk sections attached to a rail or brace. The column or trunk section 111 is attached to the rail or brace 112a,b via relatively narrow sections that bend preferentially when a horizontal force is applied to the rail or brace. Thus, the narrow sections can be considered hinges 113.

[0041] Figures 9 and 10 show an example of a rigid linkage set 300 (further described in PCT Publication WO2021175922A1 (Ocado)) for use in engaging with first and second sets of wheels of a load handling device, as part of a steering assembly having functional behavior similar to the compliant mechanism 110 described above.

[0042] The linkage set mechanism 300 comprises a series of pivotably connected two-part linkages. Considering a single two-part linkage, at one end, the primary linkage member (track portion) 311 is pivotably attached to the traveler or upper brace 312a at the knee joint 316, and the other end is hinged to the secondary linkage member (branch portion) 313 at the ankle joint 315. The opposite end of the secondary linkage 313 is pivotably attached to the fixed brace or lower brace 312b at the toe hinge 314. Thus, each single two-part linkage extends between the traveler 312a and the fixed brace 212b. To construct the linkage set 300, a series of similar two-part linkages are arranged parallel to each other between the traveler brace 312a and the fixed brace 312b, as shown in Figure 9, to constitute the linkage set 300.

[0043] The rotational or angular motion of the knee joint 316, ankle joint 315, and toe joint 314 is restricted as described below. In the ankle joint 315, the primary linkage 311 has a single knuckle that fits between the two knuckles of the secondary linkage 313.

[0044] Figure 10a shows the linkage set in the neutral or stationary position, where the first set of wheels 34 and the second set of wheels 36 are engaged with the track (shown in the thumbnail), and the load handling device 30 is not movable in either the x or y direction. In this position, no force F is applied to the traveler 312a, and the lower surface 319 of the primary linkage 311 is in contact with the upper surface 320 of the secondary linkage 313.

[0045] In Figure 10b, a positive force F (i.e., from left to right as illustrated) is applied to the traveler 312a. Applying a positive force F causes the primary linkage 311 to rotate clockwise around the knee joint 316 and counterclockwise around the ankle joint 315. The rotation around the ankle joint 315 is limited by the contact of surface 317 with surface 318. By moving the traveler 312a further to the right, the secondary linkage 313 rotates clockwise around the toe hinge 314, lifting away from the fixed brace 312b. Thus, the traveler 312a is displaced horizontally in the positive direction relative to the fixed brace 312b. The positive displacement of the traveler 312a will cause the first set of wheels 34 to be lowered so as to engage with the track, and the second set of wheels 36 to be raised (as shown in the thumbnail), allowing the cargo handling device 100 to move in the y-direction.

[0046] In Figure 10c, a negative force F (i.e., from right to left as illustrated) is applied to the traveler 312a. Applying the negative force F causes the primary linkage 311 to rotate counterclockwise around the knee joint 316 and clockwise around the ankle joint 315. The rotation around the ankle joint 315 is limited by the contact of surface 317 with surface 321, and the heel of the two-part linkage is pushed into the fixed brace 312b. As a result, the traveler 312a is displaced horizontally in the negative direction relative to the fixed brace 312b. The negative displacement of the traveler 312b will cause the first set of wheels 34 to be raised and the second set of wheels 36 to be lowered to engage with the track (illustrated in the thumbnail), allowing the cargo handling device 30 to move in the x direction.

[0047] Between the x-direction movement position and the y-direction movement position, the linkage set will be recognized as moving through a neutral or stationary position.

[0048] Figure 11 illustrates yet another exemplary reversing mechanism incorporating a reversing assembly component of a cam mechanism (further described in PCT application PCT / EP2022 / 073670 (Ocado)). Figure 11 illustrates a cam mechanism 120 for use in a reversing assembly of the type described, for example, in relation to Figure 6. The cam mechanism 120 comprises a traveler 121 (similar to 112a, 312a), a fixed brace 122 (similar to 112b or 312b), a cam profile 123 arranged as a slot in the surface of the traveler 121, and a follower 124 that engages with the cam 123 and extends between opposing surfaces or covers of the fixed brace 122. It will be recognized that the fixed brace 122 may be made from a single piece or block having sufficient depth to have a slot for accommodating the depth of the traveler 121 and positioned to hold the follower 124 in place, or the fixed brace 122 may be made from two planar material sandwiched together with the follower 124 fixed between them.

[0049] The cam or slot profile 123 extends between the first limit 125 and the second limit 126. Between these limits, as illustrated, the slot extends substantially horizontally from the first limit 125, inclined upward, and then continues substantially horizontally to the second limit 126, which has sufficient space to accommodate the follower 124.

[0050] In the first configuration of the cam mechanism 120 shown, the traveler 121 is movable horizontally and fixed vertically, while the fixed brace 122 is fixed horizontally and movable vertically. Therefore, as the cam 123 moves horizontally across the follower from the first limit 125 to the second limit 126, the fixed brace 122 will be raised by an amount equal to the vertical change in the cam profile 123. Alternatively, in the second configuration, it will be recognized that the fixed brace 122 may be fixed vertically and movable horizontally, and the traveler 121 may be fixed horizontally and movable vertically. The relative positions between the traveler 121 and the fixed brace 122 in the first configuration are illustrated in Figure 11, which shows the cam 120 in various positions.

[0051] Figures 11a-c illustrate a cam mechanism, where the front of the fixed brace 122 has been removed to make it easier to see and understand the position of the follower 124. The vertical dotted line is positioned through the follower 124 to help understand the relative position of the cam mechanism 120 between the figures.

[0052] In Figure 11a, the traveler 121 is positioned horizontally to the right. The follower 124, connected to the fixed brace 122, is positioned at the first limit 125 of the cam 123. In Figure 11b, the traveler 121 is positioned center left of the position in Figure 11a. From the position shown in Figure 11a, the cam 123 has moved relative to the follower 124 so that the follower 124 is positioned at the first inflection point of the cam slot. The fixed brace 122 has not moved its position relative to its position in Figure 11a. In Figure 11c, the traveler 122 is positioned horizontally to the left. The cam 123 has moved relative to the follower 124 so that the follower 124 had to move vertically to ascend the slope so that the follower 124 is positioned at the second limit 126. The follower 124 is fixed to the fixed brace 122, and since the fixed brace 122 is fixed horizontally, the fixed brace 122 is inevitably moved vertically. In Figures 11a and 11b, the fixed brace 122 is in a lower position relative to the traveler 121, while in Figure 11c, the fixed brace 122 is in an elevated position relative to the traveler 121.

[0053] If a pair of wheels are fixedly mounted to a fixed brace 122, it will be recognized that the cam mechanism 120 can be used to raise and lower the wheels as needed by applying a horizontal force to the traveler 121. The position of the cam 120 shown in Figure 11b can be used as the “stopped” position, where the wheels are ready to be moved to the engaged position (Figure 11a) or the disengaged position (Figure 11c). It will be recognized that the cam profile can be designed to provide any desired horizontal-to-vertical movement profile.

[0054] Figure 12 illustrates another cam mechanism 130 employing a dual-cam configuration. The first cam 133a and the second cam 133b are positioned horizontally adjacent to each other. The first cam profile 133a and the second cam profile 133b are substantially identical. Similarly, a pair of followers 124a and 124b are positioned to engage with their respective cams 133a and 133b. This configuration differs further from the configuration shown in Figures 11a-c in that the first cam 133a and the second cam 133b are positioned on fixed braces 132a and 132b, while the first follower 124a and the second follower 124b are mounted on a traveler 131, i.e., they are reversed. The fixed brace sections 132a and 132b are joined by a pair of bars.

[0055] The operation of cam mechanism 130 is similar to that of cam mechanism 120. When a horizontal force is applied to traveler 131, followers 124a and 124b move simultaneously along the first cam path 133a and the second cam path 133b, respectively, between the first limits 135a, 135b and the second limits 136a, 136b. Assuming that the fixed braces 132a and 132b are restricted to moving only vertically, the horizontal movement of traveler 131 results in the raising and lowering of the fixed braces 132a and 132b, similar to the function of cam mechanism 120. Figures 13a-c illustrate an inverted double cam mechanism 130 in positions corresponding to the positions shown for the single cam mechanism 120 in Figures 11a-c, respectively. It will be recognized that any number of cams may be used.

[0056] As seen in Figures 6 and 8, the first pair of compliant mechanisms 110 (or linkage set 300 shown in Figures 9 and 10, or cam mechanisms 120, 130 as shown in Figures 11-13) are positioned on opposing surfaces within the body or skeleton 102 of the cargo handling device to control the position of the first set 34 of wheels, and the second pair of compliant mechanisms 110 (or linkage set 300, or cam mechanisms 120, 130) are positioned on orthogonal opposing surfaces within the body or skeleton of the cargo handling device to control the position of the second set 36 of wheels. Thus, each surface of the cargo handling device is equipped with a compliant mechanism 110, or linkage set 300, or cam mechanisms 120, 130. The compliant mechanism 110, or linkage set 300, or pairs of cam mechanisms 120, 130 are coupled via a transport or drive belt 108 that substantially encircles the skeleton 102 of the load handling device and are mechanically coupled to the upper braces or travelers 112a, 312a of the compliant mechanism 110, 300, or 120, 130 of the cam mechanism's reversal assembly components.

[0057] The output of the compliant mechanism 110, or linkage set 300, or cam mechanisms 120, 130 is transmitted to the wheels 34, 36 via a chassis that converts the horizontal movement of the compliant mechanism into the vertical movement of the wheels. In some configurations, the upper braces or travelers 112a, 312a of the cam mechanism's compliant mechanism 110, 300, or 120, 130 may be attached via glide bearings to a rod configuration that extends along the plane of the load handling device 30 between each of the horizontal edges of the load handling device 30. The rod configuration may then be attached to corner pieces at first and second ends.

[0058] Wheel sets 34, 36 can be moved simultaneously via motors, for example, to engage the x-direction and / or y-direction wheel sets with the rails of the storage system grid. In this way, the reversal assembly can be operated by two motors located at opposing or adjacent corners. The use of two motors increases the torque transmitted to the drive belt. In some examples of the load handling device 30, both motors can be located in or near their respective opposing or adjacent corner pieces so as not to occupy space within the skeleton or body and for accessibility. Activating the motors in a clockwise direction can move the wheel mounts on a surface upward, raising the wheels on the surface, and lowering the wheels on the surface perpendicular to the first surface, or vice versa.

[0059] In some examples of the reversal assembly, the transport or drive belt 108 may pass over one or more free pulleys to monitor its rotational speed as it moves between engagement positions in the x and y directions, in order to provide immediate detection of belt failure. If belt 108 or another part of the reversal assembly fails, this information may be fed back to and utilized by the central control system to prevent collisions of the bot.

[0060] An exemplary drive assembly 1400 for a set of wheels 34, 36 is shown in Figure 14. A drive belt assembly is provided for each set of wheels 34, 36. The drive belt assembly comprises a pulley gear configuration of the drive belt for engaging with the toothed edges of a pair of wheels 34, 36 on one side of the load handling device 30, as illustrated in Figure 14. The toothed drive belt 1410 engages with both wheels 1420 (corresponding to a pair of wheels in a set of wheels 34 or 36). The drive belt 1410 is guided by a first drive wheel 1430 and a second drive wheel 1450, as well as two tension wheel configurations 1440, which are mounted on the load handling device. The tension wheel configurations are movably mounted on the load handling device using springs (not shown) and are intended to keep the drive belt taut and maintain engagement between the drive belt and the wheels. The drive wheel 1450 is mounted on the load handling device. The first drive wheel 1430 and the second drive wheel 1450 are connected to the axles of their respective motors (not shown in Figure 14). The use of two motors increases the torque transmitted to the drive belt.

[0061] The cargo handling device is provided with a drive assembly 1400 for each pair of wheels. The pairs of wheels on both sides comprise sets of wheels 34 and 36. The drive wheels on both sides of the cargo handling device may share a common motor axle such that each pair of wheels in sets 34 and 36 are driven simultaneously at the same speed. The first set of wheels 34 and the second set of wheels 36 may be driven selectively under the control of the cargo handling device.

[0062] In the configuration shown in Figure 14, as the set of wheels 34 and 36 are moved from their positions for engaging with the grid track, the distance between the top of the drive belt assembly and the wheels changes as the wheels are lowered and raised, so it will be recognized that the drive belt may slacken. Therefore, depending on the selected reversing assembly, an additional tensioning mechanism may be required. For example, a free pulley on a mechanical linkage connected to the reversing assembly may be employed to keep the conceptual drive belt length constant throughout the entire range of motion of the reversing assembly. Thus, the drive belt tension is optimized. Furthermore, when the bot is moving in either the x or y direction, the drive belt tension should be optimized taking into account the slip and efficiency of the drive belt.

[0063] An exemplary container lifting assembly (further described in PCT application PCT / EP2022 / 081364 (Ocado)) is shown in Figure 15. In the embodiment of Figure 15, the lifting assembly 1500 has four spools 1501, 1502, 1503, and 1504 for winding and unwinding their respective tethers 38. Spools 1501 and 1502 are on drive shaft 1505, while spools 1503 and 1504 are on drive shaft 1506. Drive shafts 1505 and 1506 are configured to rotate in opposite directions when driven by a motor. By rotating drive shafts 1505 and 1506 in opposite directions, their respective tethers 38a-d can be positioned in or near the corners of the lifting assembly, as in the embodiments described above. In particular, as shown in Figure 15, the point where each tether is wound onto or unwound from the spool is at or near each corner of the lifting assembly. This allows the tethers to connect to the container gripping device 39 at each corner of the gripping assembly, which increases stability when raising and lowering the container gripping device 39. Figure 15 shows an example of how the drive shafts 1505 and 1506 can be rotated in opposite directions. The drive shafts 1505 and 1506 are connected to pulleys 1510 and 1511, respectively. Pulleys 1507 and 1509 are connected to the axles of their respective motors (not shown in Figure 15). The use of two motors increases the torque transmitted to the drive belt 1508. The drive belt 1508 transmits torque to pulleys 1509, 1510, and 1511 so as to ensure that spools 1501 and 1502 and spools 1503 and 1504 rotate in opposite directions. In particular, pulleys 1507 and 1509 are positioned around pulley 1511, resulting in rotation opposite to that of pulley 1510.

[0064] Here, it will be recognized that the cargo handling device 30 has three systems, each of which can use a drive belt and two motors, namely a steering assembly, a drive assembly, and a container lifting assembly. The tension of the drive belt for each system should be optimized considering the slip and efficiency of the drive belt. Setting a high drive belt tension ensures that there is no slip of the drive belt, but this reduces the power efficiency of the various systems of the cargo handling device. Reducing the drive belt tension increases the possibility of slip, which means that the systems of the cargo handling device will not function in a timely and smooth manner. Any slip in the drive belt should be judged so that the drive belt tension can be adjusted accordingly. It should be recognized that these issues are common to all systems in which the slip of the drive belt should be judged so that the drive belt tension can be adjusted accordingly. The above is merely an example illustrating how an exemplary drive belt may be used in a cargo handling device. The ability to judge slip in the drive belt in any system is desirable.

[0065] Figure 16 shows a schematic diagram 1600 of a cargo handling device 30 according to the present invention. The reversal assembly 1610, as shown in Figure 6, is driven by a drive belt, a first motor, and a second motor 1620. It will be recognized that the system 1610 could instead be a drive assembly (such as the one shown in Figure 14) or a container lifting assembly (such as the one shown in Figure 15). In Figure 16, only a pair of wheels 34 for moving the cargo handling device 30 in the Y direction on a grid structure is shown. However, a complete set of wheels for each of the X and Y directions may be included, for example, a first set 34 and a second set 36 of wheels as described in the previous example. One or more current monitors 1640 allow the current drawn by the first and second motors to be monitored; that is, the current drawn by the first and second motors when started is monitored. The current monitors may be implemented, for example, by taking appropriate outputs from the motor drive circuit. In one implementation, the current monitors may be implemented on the output lines from the motor driver components. Current monitors can function in various ways. One example is a current sensor resistor, where motor current passes through the resistor and the voltage can then be measured across the resistor. From this voltage, the current can be calculated. Another example is a magnetic current sensor that uses the Hall effect to determine the current flowing from the motor driver to the output line. One or more automatic tensioning systems 1630 may be included. The cargo handling device 1600 can use a processor or controller 1650 to receive data from and transmit data to each of the following: the reversing assembly 1610, one or more sets of first and second motors and drive belts, one or more automatic tensioning systems 1630, and one or more current monitors 1640. This data can be stored in a storage device 1660. The data in the storage device 1660 can be periodically transmitted for further processing via one or more networks, such as base stations.

[0066] Figure 17 shows steps of a method 1700 for determining slippage of a drive belt used in a system comprising a drive belt and first and second motors, the first and second motors driving the drive belt. It will be recognized that the method in Figure 17 can be carried out using a system controller (e.g., a controller for the cargo handling device in Figure 16). In step 1710, first and second transient currents are received from the first and second motors, respectively, during simultaneous starting of the first and second motors to drive the drive belt. In other words, current draws from each motor during starting are received.

[0067] The simultaneous activation of the first and second motors may be for the purpose of activating a reversal assembly to raise or lower a first set of wheels and / or lower or raise a second set of wheels relative to the body or skeleton in order to engage and disengage the wheels with parallel tracks. Alternatively, the simultaneous activation of the first and second motors may be for the purpose of activating a drive assembly to drive a first or second set of wheels, respectively, to move a cargo handling device along a first or second set of parallel rails. Alternatively, the simultaneous activation of the first and second motors may be for the purpose of activating a container lifting assembly to raise or lower a container gripping device vertically. While these examples are in the context of cargo handling devices, the method in Figure 17 is applicable to any system in which the simultaneous activation of the first and second motors is used to drive a drive belt for any purpose, such as overcoming loads applied to the system.

[0068] In step 1720, slippage of the drive belt is determined to have occurred if the first and second current values ​​of the first and second transient currents differ substantially simultaneously by at least a threshold. The threshold may be a predetermined ampere (A) difference between the first and second current values. The predetermined ampere value may be an absolute value or a parameter. Alternatively, the threshold may require that the first current value differs from the second current value by a predetermined percentage, and vice versa. In other words, assuming that the first current value is higher than the second current value, it is determined whether the second current value is at least a predetermined percentage of the first current value that is lower than the first current value. Alternatively, it is determined whether the first current value is at least a predetermined percentage of the second current value that is higher than the second current value. In practice, the threshold allows for the detection of patterns in the first and second transient currents where the first and second current values ​​deviate significantly from each other over a given time. In particular, a rapid increase in one transient current and a simultaneous rapid decrease in the other transient current is a pattern that indicates slippage of the drive belt.

[0069] To improve accuracy, thresholds may require both a predetermined ampere value and a predetermined percentage to be met. Percentage thresholds are easily detectable, but requiring a minimum ampere difference also ensures that transient current noise is not interpreted as belt slip. The threshold used will vary depending on the system configuration, but it will nevertheless be recognized as being set to determine drive belt slip.

[0070] Figure 18 shows a plot / graph 1800 having a first transient current 1810 and a second transient current 1820, and a region 1830 where belt slippage is detected. The threshold in this example requires that (1) the first current value and the second current value differ by at least 0.8A, and (2) the second current value is at least 20% lower than the first current value. In practice, patterns of first and second transient currents indicating drive belt slippage are detected. Figure 19 shows a plot / graph 1900 having a first transient current 1910 and a second transient current 1920, and a plurality of regions 1930 where belt slippage is detected.

[0071] Advantageously, the method shown in Figure 17 can be used to determine drive belt slippage using the system's existing hardware. System downtime for observation is not required.

[0072] The method shown in Figure 17 can be used in several applications. One such application is to perform this method as part of the system boot sequence. Once it is determined that no slippage has occurred in the drive belt, the system can proceed to normal operation.

[0073] Another application is to correlate detected drive belt slip with the operation of the system. For example, if slip is detected simultaneously within a system's operating cycle, there may be some aspect of the system causing the slip. While it may be possible to overcome this type of slip by increasing the drive belt tension, doing so may mean that the system is not running at optimal efficiency. Therefore, this information can be used to improve the system design. Similarly, if multiple slips are detected within a system's operating cycle, it can be concluded that the drive belt tension is considerably lower than the optimal drive belt tension.

[0074] Another application is to increase the drive belt tension when it is determined that slippage has occurred in the drive belt. Additionally or alternatively, the drive belt tension may be decreased when it is determined that no slippage has occurred. Decreasing the belt tension aims to improve efficiency to the extent possible without introducing belt slippage. The system may include an automatic tensioning system 1630, such as connecting one of the tension wheel configurations 1440 to a stepping motor that can move the tension wheel configuration to increase / decrease the drive belt tension to an optimal value. Another example of an automatic tensioning system is a linear actuator that moves a tension pulley on which the drive belt operates. Moving the tension pulley via a linear actuator can increase the drive belt tension. Generally, an automatic tensioning system moves a pulley or drive belt guide to increase the drive belt tension. As described above, the drive belt tension may be estimated to be considerably lower than the optimal tension. Once the automatic tensioning system adjusts the tension, the method shown in Figure 17 can be re-executed to ensure that no more slippage has occurred in the drive belt. Such information can be used by a processor / controller to control the degree to which the automatic tensioning system increases the tension of the drive belt.

[0075] In this document, the phrase "movement in the direction of n" (and related expressions) where n is one of x, y, and z is intended to mean movement substantially along or parallel to the n axis in either direction (i.e., toward the positive end of the n axis or toward the negative end of the n axis).

[0076] In this document, the word “connect” and its derivatives are intended to include the possibility of direct and indirect connection. For example, “x is connected to y” is intended to include the possibility of x being directly connected to y without any intervening components, and the possibility of x being indirectly connected to y with one or more intervening components. When direct connection is intended, the words “directly connected,” “directly connected,” or similar words will be used. Similarly, the word “support” and its derivatives are intended to include the possibility of direct and indirect contact. For example, “x supports y” is intended to include the possibility of x directly supporting y and directly contacting y without any intervening components, and the possibility of x indirectly supporting y with one or more intervening components that contact x and / or y. The word “install” and its derivatives are intended to include the possibility of direct and indirect installation. For example, "x is installed on y" is intended to include both the possibility that x is directly installed on y without any intervening components, and the possibility that x is indirectly installed on y with one or more intervening components.

[0077] In this document, the word "to possess" and its derivatives are intended to have an inclusive rather than exclusive meaning. For example, "x possesses y" is intended to include the possibility that x may contain one y, just one y, multiple ys, or one or more ys, as well as one or more other elements. If an exclusive meaning were intended, the phrase "x consists of y" would be used, meaning that x contains only y and nothing else.

[0078] In this document, “controller” is intended to include any hardware suitable for controlling (e.g., providing instructions to) one or more other components. For example, a processor equipped with one or more memories and suitable software for processing data about one or more components and sending appropriate instructions to the component(s) to enable them to perform their intended functions.

[0079] Where used herein, the singular forms “a,” “an,” and “the” are intended to include the plural form unless the context explicitly indicates otherwise. It will be further understood that, when used herein, the terms “comprises” and / or “comprising” identify the presence of a described feature, integer, step, action, element, and / or component, but do not exclude the presence or addition of one or more other features, integers, steps, actions, elements, components, and / or groups thereof.

[0080] The present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment that includes both hardware and software elements. In a preferred embodiment, the present invention is implemented in software.

[0081] Furthermore, the present invention may take the form of a computer program embodied as a computer-readable medium having computer-executable code for use by or in connection with a computer. For the purposes of this description, the computer-readable medium may be any tangible device capable of containing, storing, communicating, propagating, or carrying a program for use by or in connection with a computer. Moreover, the computer-readable medium may be an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system (or apparatus or device), or a propagation medium. Examples of computer-readable mediums include semiconductor or solid-state memory, magnetic tape, removable computer diskettes, random-access memory (RAM), read-only memory (ROM), rigid magnetic disks, and optical disks. Current examples of optical disks include compact disc read-only memory (CD-ROM), compact disc read / write (CD-R / W), and DVD.

[0082] The flowcharts in the drawings illustrate the architecture, functionality, and operation of possible implementations of the methods according to various embodiments of the present invention. In this regard, each block in the flowchart may represent a module, segment, or portion of code, and they comprise one or more executable instructions for performing a specified logical function. Note that in some alternative implementations, the functions described in the blocks may not occur in the order shown in the drawings. For example, depending on the functionality involved, two blocks shown consecutively may actually be executed substantially simultaneously, or they may sometimes be executed in reverse order. Note that each block in the flowchart and any combination of blocks in the flowchart may be implemented by a dedicated hardware-based system that performs a specified function or operation, or a combination of dedicated hardware and computer instructions.

[0083] The above description is given only as an example, and it will be understood that various modifications can be made by those skilled in the art. Although various embodiments have been described above with some degree of specificity or by reference to one or more individual embodiments, those skilled in the art can make numerous modifications to the disclosed embodiments without departing from the scope of the invention.

[0084] The following is a non-exhaustive list of embodiments that may or may be claimed:

[0085] [Embodiment 1] This system is for determining slippage of the drive belt, and this system is The drive belt and First and second motors configured to drive a drive belt, Controller and The controller is equipped with, During the simultaneous startup of the first and second motors for driving the drive belt, the system receives first and second transient currents from the first and second motors, respectively. The slippage of the drive belt is determined when the first and second current values ​​of the first and second transient currents differ substantially simultaneously by at least a threshold amount. A system configured to perform the following actions.

[0086] [Embodiment 2] The threshold is, The minimum percentage difference between the first current value and the second current value, and / or Minimum amperage difference between the first current value and the second current value The system according to Embodiment 1, as defined by [the relevant authority].

[0087] [Embodiment 3] A cargo handling device for lifting and moving storage containers (10) stacked in a grid framework structure, wherein the grid framework structure is The system comprises a first set of parallel rails or tracks and a second set of parallel rails or tracks extending substantially perpendicular to the first set of parallel rails or tracks in a substantially horizontal plane to form a grid pattern comprising multiple grid spaces, wherein the grid is supported by sets of upright members to form multiple vertical storage locations directly beneath the grid, such that containers are stacked vertically between sets of upright members and guided by sets of upright members through multiple grid spaces, and the cargo handling device is A body or skeleton mounted on a first set of wheels arranged to engage with a first set of parallel tracks, and a second set of wheels arranged to engage with a second set of parallel tracks, A drive assembly comprising the first system described in Embodiment 1 or 2, wherein the drive belt and first and second motors of the first system are configured to drive a first or second set of wheels to move a load handling device along a first or second set of parallel rails, and the controller of the first system is configured to receive first and second transient currents from the first and second motors of the first system while the first or second set of wheels are being driven, and / or A steering assembly comprising the second system described in Embodiment 1 or 2, wherein the drive belt and first and second motors of the second system are configured to raise or lower a first set of wheels and / or lower or raise a second set of wheels relative to a body or skeleton to engage and disengage the wheels with parallel tracks, and the controller of the second system is configured to receive first and second transient currents from the first and second motors of the second system, respectively, during the raising or lowering of the first set of wheels and / or the lowering or raising of the second set of wheels, and / or A container lifting assembly comprising the third system described in Embodiment 1 or 2, wherein the drive belt and first and second motors of the third system are configured to raise or lower a gripping device in the vertical direction, and the controller of the third system is configured to receive first and second transient currents from the first and second motors of the third system, respectively, during the raising or lowering of the gripping device. A cargo handling device equipped with the following features.

[0088] [Embodiment 4] The cargo handling device according to Embodiment 3, wherein the steering assembly is arranged to raise or lower a first set of wheels and to synchronously lower or raise a second set of wheels relative to the body.

[0089] [Embodiment 5] The steering assembly is Either the first or second set of wheels, Each of the first and second sets of wheels A cargo handling device according to embodiment 3 or 4, further comprising at least one direction-changing mechanism.

[0090] [Embodiment 6] The cargo handling device according to any one of embodiments 3 to 5, wherein the steering assembly comprises two steering mechanisms for each of the first and second sets of wheels.

[0091] [Embodiment 7] A cargo handling device according to embodiment 5 or 6, wherein the direction-changing mechanism or each direction-changing mechanism is driven by a drive belt.

[0092] [Embodiment 8] The cargo handling device according to any one of embodiments 3 to 6, wherein the two motors are installed in opposing or adjacent locations within the cargo handling device.

[0093] [Embodiment 9] The cargo handling device according to Embodiment 8, wherein the opposing or adjacent location comprises a corner of the cargo handling device.

[0094] [Embodiment 10] The opposite or adjacent location or corner is on the main body or skeleton, the cargo handling device according to Embodiment 8.

[0095] [Embodiment 11] A cargo handling device according to any one of embodiments 3 to 10, wherein the drive belt substantially encircles the skeleton or body of the cargo handling device.

[0096] [Embodiment 12] The system according to any one of embodiments 1 to 11, further comprising an automatic tensioning device, wherein the controller is further configured to control the automatic tensioning device to increase the tension of the drive belt when it determines that slippage has occurred in the drive belt, and / or to decrease the tension of the drive belt when it determines that slippage has not occurred in the drive belt.

[0097] [Embodiment 13] A method for determining slippage of a drive belt in a system comprising a drive belt, first and second motors configured to drive the drive belt, and a controller, wherein the method uses the controller, During the simultaneous startup of the first and second motors for driving the drive belt, the system receives first and second transient currents from the first and second motors, respectively. The slippage of the drive belt is determined when the first and second current values ​​of the first and second transient currents differ substantially simultaneously by at least a threshold amount. A method that includes [a certain feature].

[0098] [Embodiment 14] The threshold is, The minimum percentage difference between the first current value and the second current value, and / or Minimum amperage difference between the first current value and the second current value The method according to Embodiment 13, as defined by [the relevant source].

[0099] [Embodiment 15] A method for operating a cargo handling device for lifting and moving storage containers stacked within a grid framework structure, wherein the grid framework structure is The system comprises a first set of parallel rails or tracks and a second set of parallel rails or tracks extending substantially perpendicular to the first set of parallel rails or tracks in a substantially horizontal plane to form a grid pattern comprising multiple grid spaces, wherein the grid is supported by sets of upright members to form multiple vertical storage locations directly beneath the grid, such that containers are stacked vertically between sets of upright members and guided by sets of upright members through multiple grid spaces, and the cargo handling device is A body or skeleton mounted on a first set of wheels arranged to engage with a first set of parallel tracks, and a second set of wheels arranged to engage with a second set of parallel tracks, A drive assembly comprising a first drive belt, a first motor, and a second motor configured to drive a first or second set of wheels, respectively, to move a load handling device along a first or second set of parallel rails, wherein the first method described in Embodiment 13 or 14 is used to receive first and second transient currents from the first and second motors, respectively, while driving the first or second set of wheels, and / or A steering assembly comprising a second drive belt, a third motor, and a fourth motor configured to raise or lower a first set of wheels and / or lower or raise a second set of wheels relative to a body or skeleton in order to engage and disengage the wheels with parallel tracks, wherein the second method described in Embodiment 13 or 14 is used to receive first and second transient currents from the third and fourth motors, respectively, during the raising or lowering of the first set of wheels and / or the lowering or raising of the second set of wheels, and / or A container lifting assembly comprising a third drive belt, a fifth motor, and a sixth motor configured to raise or lower a gripping device in the vertical direction, wherein the third method described in Embodiment 13 or 14 is used to receive first and second transient currents from the fifth and sixth motors, respectively, during the raising or lowering of the gripping device. A method that includes [a certain feature].

[0100] [Embodiment 16] The method according to embodiment 15, wherein the steering assembly is positioned to raise or lower a first set of wheels and to synchronously lower or raise a second set of wheels relative to the body.

[0101] [Embodiment 17] The steering assembly is Either the first or second set of wheels, Each of the first and second sets of wheels The method according to embodiment 15 or 16, further comprising at least one direction-changing mechanism.

[0102] [Embodiment 18] The method according to any one of embodiments 15 to 17, wherein the steering assembly comprises two steering mechanisms for each of the first and second sets of wheels.

[0103] [Embodiment 19] The method according to embodiment 17 or 18, wherein the steering mechanism or each steering mechanism is driven by a drive belt of the second system.

[0104] [Embodiment 20] The method according to any one of embodiments 15 to 19, wherein the third and fourth motors are installed in locations opposite or adjacent to the cargo handling device.

[0105] [Embodiment 21] The method according to embodiment 20, wherein the opposing or adjacent location comprises a corner of the cargo handling device.

[0106] [Embodiment 22] The method according to Embodiment 20, wherein the opposing or adjacent location or corner is on the main body or skeleton.

[0107] [Embodiment 23] The method according to any one of embodiments 15 to 22, wherein the second drive belt substantially encircles the skeleton or body of the cargo handling device.

[0108] [Embodiment 24] The method according to any one of embodiments 15 to 23, further comprising an automatic tensioning device, wherein the method further comprises using a controller to control the automatic tensioning device to increase the tension of the drive belt when it is determined that slippage has occurred in the drive belt, and / or to decrease the tension of the drive belt when it is determined that slippage has not occurred in the drive belt.

[0109] [Embodiment 25] A computer program comprising instructions, wherein, when the computer program is executed by a computer, the instructions cause the computer to perform the method described in any one of embodiments 15 to 24.

[0110] [Embodiment 26] A data processing system comprising a processor configured to perform the method described in any one of embodiments 15 to 24. The following is a direct reproduction of the claims as originally filed. [1] A system for determining slippage of a drive belt, wherein the system is Drive belt and First and second motors configured to drive the aforementioned drive belt, Controller and The controller is equipped with, The first and second motors for driving the drive belt receive first and second transient currents from the first and second motors, respectively, during simultaneous startup of the first and second motors. The slippage of the drive belt is determined when the first and second current values ​​of the first and second transient currents differ substantially simultaneously by at least a threshold amount. A system configured to perform the following actions. [2] The threshold is, The minimum percentage difference between the first current value and the second current value, and / or Minimum amperage difference between the first current value and the second current value The system as defined by [1]. [3] A cargo handling device for lifting and moving storage containers stacked in a grid framework structure, wherein the grid framework structure is The cargo handling device comprises a first set of parallel rails or tracks and a second set of parallel rails or tracks extending substantially perpendicular to the first set of parallel rails or tracks in a substantially horizontal plane to form a grid pattern comprising a plurality of grid spaces, wherein the grid is supported by the set of upright members to form a plurality of vertical storage locations directly beneath the grid, such that containers are stacked vertically between sets of upright members through a plurality of grid spaces and guided by the set of upright members, and the cargo handling device is A body or skeleton mounted on a first set of wheels arranged to engage with a first set of parallel tracks, and a second set of wheels arranged to engage with a second set of parallel tracks, A drive assembly comprising a first system which is the system described in [1] or [2], wherein the drive belt and first and second motors of the first system are configured to drive a first or second set of wheels to move the load handling device along a first or second set of parallel rails, and the controller of the first system is configured to receive the first and second transient currents from the first and second motors of the first system while the first or second set of wheels are being driven, and / or A reversible assembly comprising a second system which is the system described in [1] or [2], wherein the drive belt and first and second motors of the second system are configured to raise or lower a first set of wheels and / or lower or raise a second set of wheels relative to the body or skeleton in order to engage and disengage the wheels with the parallel tracks, and the controller of the second system is configured to receive the first and second transient currents from the first and second motors of the second system, respectively, during the raising or lowering of the first set of wheels and / or the lowering or raising of the second set of wheels, and / or A container lifting assembly comprising a third system which is the system described in [1] or [2], wherein the drive belt and first and second motors of the third system are configured to raise or lower the gripping device in the vertical direction, and the controller of the third system is configured to receive the first and second transient currents from the first and second motors of the third system, respectively, during the raising or lowering of the gripping device. A cargo handling device equipped with the following features. [4] The cargo handling device according to [3], wherein the steering assembly is arranged to raise or lower the first set of wheels and to synchronously lower or raise the second set of wheels relative to the body. [5] The direction change assembly is Either of the first or second set of the aforementioned wheels, Each of the first and second sets of the aforementioned wheels A cargo handling device according to [3] or [4], comprising at least one steering mechanism for the load. [6] The cargo handling device according to any one of [3] to [5], wherein the steering assembly comprises two steering mechanisms for each of the first and second sets of wheels. [7] The cargo handling device according to [5] or [6], wherein the steering mechanism or each steering mechanism is driven by the drive belt of the second system. [8] The first and second motors are installed in a location opposite or adjacent to the cargo handling device, as described in any one of [3] to [6]. [9] The cargo handling device according to [8], wherein the opposing or adjacent location comprises a corner of the cargo handling device.

[10] The opposite or adjacent location or corner is on the main body or skeleton, the cargo handling device as described in [8].

[11] The drive belt substantially encircles the skeleton or body of the cargo handling device, as described in any one of [3] to

[10] .

[12] The system further comprises an automatic tensioning device, wherein the controller is further configured to control the automatic tensioning device to increase the tension of the drive belt when it determines that the drive belt is slipping, and / or to decrease the tension of the drive belt when it determines that the drive belt is not slipping, the system according to any one of [1] to

[11] .

[13] A method for determining slippage of a drive belt in a system, wherein the system comprises the system described in any one of [1] to

[12] , and the method uses the controller, The first and second motors for driving the drive belt receive first and second transient currents from the first and second motors, respectively, during simultaneous startup of the first and second motors. When the first and second current values ​​of the first and second transient currents differ substantially simultaneously by at least a threshold amount, it is determined that slippage of the drive belt has occurred. A method that includes [a certain feature].

[14] A computer program comprising instructions, wherein, when the computer program is executed by the computer, the instructions cause the computer to perform the method described in

[13] . A data processing system comprising a processor configured to perform the method described in

[15]

[13] .

Claims

1. A system for determining slippage of a drive belt, wherein the system is Drive belt and First and second motors configured to drive the aforementioned drive belt, Controller and The controller is equipped with, The first and second motors for driving the drive belt receive first and second transient currents from the first and second motors, respectively, during simultaneous startup of the first and second motors. The slippage of the drive belt is determined when the first and second current values ​​of the first and second transient currents differ substantially simultaneously by at least a threshold amount. A system configured to perform the following actions.

2. The aforementioned threshold is, The minimum percentage difference between the first current value and the second current value, and / or Minimum amperage difference between the first current value and the second current value The system according to claim 1, as defined by [the relevant law].

3. A cargo handling device for lifting and moving storage containers stacked in a grid framework structure, wherein the grid framework structure is The cargo handling device comprises a first set of parallel rails or tracks and a second set of parallel rails or tracks extending substantially perpendicular to the first set of parallel rails or tracks in a substantially horizontal plane to form a grid pattern comprising a plurality of grid spaces, wherein the grid is supported by the set of upright members to form a plurality of vertical storage locations directly beneath the grid, such that containers are stacked vertically between sets of upright members through a plurality of grid spaces and guided by the set of upright members, and the cargo handling device is A body or skeleton mounted on a first set of wheels arranged to engage with a first set of parallel tracks, and a second set of wheels arranged to engage with a second set of parallel tracks, A drive assembly comprising a first system which is the system described in claim 1 or 2, wherein the drive belt and first and second motors of the first system are configured to drive a first or second set of wheels to move the load handling device along a first or second set of parallel rails, and the controller of the first system is configured to receive the first and second transient currents from the first and second motors of the first system while the first or second set of wheels are being driven, and / or A steering assembly comprising a second system which is the system according to claim 1 or 2, wherein the drive belt and first and second motors of the second system are configured to raise or lower a first set of wheels and / or lower or raise a second set of wheels relative to the body or skeleton in order to engage and disengage the wheels with the parallel tracks, and the controller of the second system is configured to receive the first and second transient currents from the first and second motors of the second system, respectively, during the raising or lowering of the first set of wheels and / or the lowering or raising of the second set of wheels, and / or A container lifting assembly comprising a third system which is the system according to claim 1 or 2, wherein the drive belt and first and second motors of the third system are configured to raise or lower the gripping device in the vertical direction, and the controller of the third system is configured to receive the first and second transient currents from the first and second motors of the third system, respectively, during the raising or lowering of the gripping device. A cargo handling device equipped with the following features.

4. The cargo handling device according to claim 3, wherein the direction-changing assembly is positioned relative to the main body to raise or lower the first set of wheels and to synchronously lower or raise the second set of wheels, respectively.

5. The aforementioned direction change assembly is Either of the first or second set of the aforementioned wheels, Each of the first and second sets of the wheels The cargo handling device according to claim 3, further comprising at least one direction-changing mechanism.

6. The cargo handling device according to claim 3, wherein the steering assembly comprises two steering mechanisms for each of the first and second sets of wheels.

7. The cargo handling device according to claim 5, wherein the direction-changing mechanism or each direction-changing mechanism is driven by the drive belt of the second system.

8. The cargo handling device according to claim 3, wherein the first and second motors are installed in locations opposite or adjacent to the cargo handling device.

9. The cargo handling device according to claim 8, wherein the opposing or adjacent location comprises a corner of the cargo handling device.

10. The cargo handling device according to claim 8, wherein the opposing or adjacent location or corner is on the main body or skeleton.

11. The cargo handling device according to claim 3, wherein the drive belt substantially encircles the skeleton or body of the cargo handling device.

12. The system according to claim 1 or 2, further comprising an automatic tensioning device, wherein the controller is further configured to control the automatic tensioning device such that it increases the tension of the drive belt when it determines that the drive belt is slipping, and / or decreases the tension of the drive belt when it determines that the drive belt is not slipping.

13. A method for determining slippage of a drive belt in a system, wherein the system comprises the system described in claim 1 or 2, and the method uses the controller, The first and second motors for driving the drive belt receive first and second transient currents from the first and second motors, respectively, during simultaneous startup of the first and second motors. When the first and second current values ​​of the first and second transient currents differ substantially simultaneously by at least a threshold amount, it is determined that slippage of the drive belt has occurred. A method that includes [a certain feature].

14. A computer program comprising instructions, wherein, when the computer program is executed by a computer, the instructions cause the computer to use the controller to carry out the method according to claim 13.

15. A data processing system comprising a computer processor configured to perform the method according to claim 13 using the controller.

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