Systems and methods involving catwalks in an order fulfillment system

Abstract

An order fulfillment system including a mobile robot and a storage structure accessible by the mobile robot. The storage structure includes multiple horizontal levels, an aisle extending through the storage structure, storage locations accessible by the mobile robot from each of multiple horizontal levels; and a catwalk that supports a weight of a human to allow the human to traverse at least a portion of the length of the aisle. The catwalk includes sections, each of which is statically disposed at aisles at two or more horizontal levels and extending along the length of an aisle at a corresponding horizontal level. Each section is shorter than the length of the aisle. Horizontally adjacent sections are arranged with a vertical gap therebetween that is greater than a height of the mobile robot transporting the tote and less than a vertical distance between two adjacent horizontal levels of the multiple horizontal levels.

Description

Aty. Docket No. 1127P017369- WO (PCT)SYSTEMS AND METHODS INVOLVING CATWALKS INAN ORDER FULFILLMENT SYSTEMCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is a non-provisional of and claims the benefit of United States provisional application number 63 / 682,678 filed on August 13, 2024, the disclosure of which is incorporated herein by reference in its entirety.BACKGROUND1. Field

[0002] This invention relates generally to order fulfillment systems, and more particularly, to catwalks at order fulfillment systems suitable for mobile robots and humans.2. Brief Description of Related Developments

[0003] In facilities, such as order fulfillment facilities, multiple mobile robots may be employed to pick and transfer containers in the context of an order fulfillment system, or an automated storage and retrieval system. Occasionally, a mobile robot may become damaged, incapacitated, or otherwise cease to function in some intended manner. When this situation occurs, it may require an individual to be able to access the mobile robot for repair, maintenance, and / or recovery.

[0004] Dynamic catwalks have been used at some facilities to allow individuals to traverse the storage structure in a horizontal direction. Dynamic catwalks are motorized horizontal barriers for the safe movement of personnel within the structure. They may need to open and / or close every time system entry by personnel is required, and their relative complexity may lead to operational malfunctions and repairs. In other words, dynamic catwalks that are movable (such as motorized catwalks movable between open and closed positions) to allow traversal by users or mobile robots may be complex and involve a number of components for operation. In some circumstances, it may be desirable to employ a fixed, or static, catwalk composed of a series of fixed, staggeredAty. Docket No. 1127P017369- WO (PCT) catwalk sections (or segments). A static catwalk may allow movement of both users and mobile robots within the same portions of the facility, although not necessarily at the same time.

[0005] Accordingly, the present disclosure addresses a number of those issues.BRIEF DESCRIPTION OF THE DRAWINGS

[0006] The foregoing aspects and other features of the present disclosure are explained in the following description, taken in connection with the accompanying drawings, wherein:

[0007] Figs. 1-4 illustrates portions of an order fulfdlment system in accordance with the present disclosure;

[0008] Fig. 5 illustrates a partial and simplified overhead view of a horizontal level of the order fulfillment system of Figs. 1-4 in accordance with the present disclosure;

[0009] Figs. 6-9 illustrate exemplary static catwalks that may be employed within the order fulfillment system of Figs. 1-4 in accordance with the present disclosure;

[0010] Fig. 10 illustrates an exemplary catwalk that may be employed within the order fulfillment system of Figs. 1-4 in accordance with the present disclosure;

[0011] Fig. 11 illustrates an exemplary catwalk that may be employed within the order fulfillment system of Figs. 1-4 in accordance with the present disclosure;

[0012] Figs. 12-14 illustrate exemplary staggered arrangements of catwalk sections and paths mobile robots may take, within the order fulfillment system of Figs. 1-4, to move to reach a vertical destination in accordance with the present disclosure; and

[0013] Fig. 15 illustrates an exemplary process flow diagram in accordance with the present disclosure.Aty. Docket No. 1127P017369- WO (PCT)DETAILED DESCRIPTION

[0014] The following detailed description is meant to assist the understanding of one skilled in the art, and is not intended in any way to unduly limit claims connected or related to the present disclosure.

[0015] The following detailed description references various figures, where like reference numbers refer to like components and features across various figures, whether specific figures are referenced, or not.

[0016] The word “each” as used herein refers to a single object (i.e., the object) in the case of a single object or each object in the case of multiple objects. The words “a,” “an,” and “the” as used herein are inclusive of “at least one” and “one or more” so as not to limit the object being referred to as being in its “singular” form.

[0017] Spatial terms such as “left,” “right,” “top,” “bottom,” “upper,” “lower,” “front,” “back,” “vertical,” and “horizontal” as may be used herein are by way of example and illustration only are not meant to limit the description and may be exchanged in position and orientation.

[0018] The terms “substantially” and “about” as may be used herein refer to a feature that may be varied within an acceptable manufacturing tolerance for a given application.

[0019] Generally speaking, pursuant to the present disclosure, systems, apparatuses and methods are provided herein useful to catwalks at order fulfillment systems. In accordance with the present disclosure, an order fulfillment system includes: a mobile robot configured to transport a tote carrying at least one product, and a storage structure accessible by the mobile robot. Further, the storage structure includes: multiple horizontal levels, each offset vertically from an adjacent horizontal level; an aisle extending through the storage structure, the aisle including: tracks extending along a length of the aisle and along which the mobile robot travels; and channels each extending along a height of the aisle and along which the mobile robot travels to move vertically from one horizontal level to another horizontal level of the storage structure. The storage structure also includes: storage locations accessible by the mobile robot from each of multiple horizontal levels; and a catwalk configured to support a weight of a human to allow the human to traverse at least a portion of the length of the aisle, wherein the catwalk comprises sections each of which isAty. Docket No. 1127P017369- WO (PCT) statically disposed at aisles at two or more horizontal levels and extending along the length of an aisle at a corresponding horizontal level, wherein each section is shorter than the length of the aisle at the corresponding horizontal level, and wherein horizontally adjacent sections are arranged with a vertical gap therebetween that is greater than a height of the mobile robot transporting the tote and less than a vertical distance between two adjacent horizontal levels of the multiple horizontal levels.

[0020] In accordance with the present disclosure, one or more of the following may be provided: in the system, one end of one section of the catwalk overlaps with one end of a horizontally adjacent section of the catwalk, and an opposite end of the one section and an opposite end of the horizontally adjacent section extend in opposite directions; an overlap between the horizontally adjacent sections is disposed out of the channels. In some implementations, the horizontally adjacent sections of the catwalk are arranged without a horizontal gap; the horizontally adjacent sections of the catwalk are staggered with the vertical gap; each section of the catwalk is arranged to be one level lower along the length of the aisle; the vertical gap is configured to allow a user to move from one section to a horizontally adjacent section with a single step; the vertical gap is 14 to 18 inches (or 35.56 cm to 45.72 cm); a length of one or more sections of the catwalk are greater than a distance between two or more adjacent channels. In some implementations, one or more sections of the catwalk extend to and contact in-rack transit planes (IRTPs); the mobile robot is configured to move from one channel to another channel via the tracks in the event that there is a section of the catwalk that blocks a directed vertical movement of the mobile robot from one horizontal level to an adjacent horizontal level via the one channel; the mobile robot includes a radio frequency identification tag configured to provide information of a location of the mobile robot; the mobile robot is configured to pause or alter its path when a human is detected within the aisle; and the catwalk does not include a dynamic section configured to dynamically change its position.

[0021] In accordance with the present disclosure, there is provided a method of order fulfillment. The method includes: determining a current location of a mobile robot configured to transport a tote carrying products; and routing the mobile robot within a storage structure to retrieve and transport a tote carrying at least one product between multiple horizontal levels, each offset vertically from an adjacent horizontal level, via channels each establishing vertical paths betweenAty. Docket No. 1127P017369- WO (PCT) the multiple horizontal levels and along an aisle extending through the storage structure, the aisle comprising tracks extending along a length of the aisle and along which the mobile robot travels. Further, in the method, the step of routing the mobile robot includes directing the mobile robot to move vertically from one horizontal level to an adjacent horizontal level via one of the channels that provides a direct vertical path from the one horizontal level to the adjacent horizontal level, wherein the direct vertical path is unobstructed by a catwalk configured to support a weight of a human to allow the human to traverse at least a portion of the length of the aisle, wherein the catwalk comprises sections each of which is statically disposed at aisles at two or more horizontal levels and extending along the length of an aisle at a corresponding horizontal level, wherein each section is shorter than the length of the aisle at the corresponding horizontal level, and wherein horizontally adjacent sections are arranged with a vertical gap therebetween that is greater than a height of the mobile robot transporting the tote and less than a vertical distance between two adjacent horizontal levels of the multiple horizontal levels.

[0022] In accordance with the present disclosure the method may be implemented with one or more of the step of routing the mobile robot includes directing the mobile robot to move from one channel to another channel via the tracks in the event that there is a section of the catwalk that blocks a directed vertical movement of the mobile robot from the one horizontal level to the adjacent horizontal level via the one channel; the step of determining the current location of the mobile robot includes identifying a location of the mobile robot using a radio frequency identification tag; the method further includes directing the mobile robot to pause or alter its path when a human is detected within the aisle; the horizontally adjacent sections of the catwalk are staggered with the vertical gap; and each section of the catwalk is arranged to be one level lower along the length of the aisle.

[0023] In accordance with the present disclosure, and without limitation, this disclosure is directed generally to a facility, such as an order fulfillment facility, that includes multiple mobile robots (or bots) that operate to pick and transfer containers in the context of an order fulfillment system, or an automated storage and retrieval system. In one form, mobile robots move about the facility along horizontal and / or vertical pathways and retrieve containers, or totes, of goods that are stored in specific storage locations in the facility, as part of the automated storage and retrieval system. Occasionally, a mobile robot may become damaged, incapacitated, or otherwise cease toAty. Docket No. 1127P017369- WO (PCT) function in some intended manner. When this situation occurs, it may require an individual to be able to access the mobile robot for repair, maintenance, and / or recovery.

[0024] In accordance with the present disclosure, and without limitation, it may be desirable to implement a catwalk system at a facility that suits both users and mobile robots. Dynamic catwalks have been used at some facilities to allow individuals to traverse the storage structure in a horizontal direction. Dynamic catwalks are motorized horizontal barriers for the safe movement of personnel within the structure. They may need to open and / or close every time system entry by personnel is required, and their relative complexity may lead to operational malfunctions and repairs. In other words, dynamic catwalks that are movable (such as motorized catwalks movable between open and closed positions) to allow traversal by users or mobile robots may be complex and involve a number of components for operation. In some circumstances, it may be desirable to employ a fixed, or static, catwalk composed of a series of fixed, staggered catwalk sections (or segments). A static catwalk may allow movement of both users and mobile robots within the same portions of the facility, although not necessarily at the same time.

[0025] In accordance with the present disclosure, and without limitation, this disclosure addresses a static catwalk system that allows a user to safely traverse within a 3D storage rack structure where mobile robots navigate vertically and horizontally. The disclosure addresses a static catwalk system that allows movement and navigation by both users / individuals and mobile robots. The static catwalk system may include an array of multiple static catwalk sections arranged in a staggered configuration that enhances safety for users and that allows the mobile bots to navigate the 3D storage rack structure vertically by navigating around a catwalk section when its vertical path is blocked by the catwalk section. The catwalk sections may be strategically placed with a predetermined vertical clearance between levels, which is an appropriate step height for humans but also allows mobile robots to pass underneath. The catwalk sections may be disposed either without any horizontal gap or with a minimal horizontal gap that effectively prevents users from falling through.

[0026] Figs. 1-4 show parts of an order fulfillment system 100, which may be referred to alternatively as an order fulfillment system, an order fulfillment facility, or a storage facility herein. The order fulfillment system 100 utilizes an automated storage and retrieval system (ASRS). MoreAty. Docket No. 1127P017369- WO (PCT) specifically, as part of the ASRS, Figures 1 and 2 show a storage structure 102 that is generally intended to store various items at a number of storage locations 104. The storage structure 102 may include an array of storage locations 104 in horizontal rows and climbing channels 105 (also referred to as level changing towers) along the rows. The mobile robots may travel between storage levels in the z-direction within the climbing channels 105. Rows of storage locations 104 may be arranged to face each other, separated by horizontal pathways or aisles 106.

[0027] The storage structure 102 may include decks 108 (which may also be referred to herein as in-rack transit planes (IRTPs), transit planes, or transit areas) spaced apart at different horizontal levels of the storage structure 102. The decks 108 may extend between the aisles 106 so that mobile robots can maneuver in the x-y plane of each deck 108 to travel between different aisles 106. Further details relating to the general structure and operation of embodiments of storage structures and mobile robots, such as may be used in conjunction with this disclosure, are disclosed in U.S. Patent No. 9,139,363, issued September 22, 2015, entitled “Automated System for Transporting Payloads”; U.S. Patent No. 10,040,632, issued August 7, 2018, entitled” Automated System for Transporting Payloads”; U.S. Patent 10,435,241, issued October 8, 2019, entitled “Storage and Retrieval System”; U.S. Patent No. 10,952,533, issued March 23, 2021, entitled “Modular Structure for an Automated Storage and Retrieval System”; and U.S. Patent No. 11,142,398, issued October 12, 2021, entitled “Order Fulfillment System”; which patents are all incorporated by reference herein in their entirety.

[0028] Figs. 3 and 4 show workstations 110 at the system / facility 100. In accordance with the present disclosure, operators (human individuals and / or robotic operators) work at the workstations 110 and may transfer products / items / eaches to containers. Mobile robots may perform transport operations, including moving containers (or totes) of products between storage locations 104 and the workstations 110 and including transporting order containers away from the workstations 110. Examples of workstations 110 and picking and transfer operations, such as may be used in conjunction with this disclosure, are disclosed, for example, in U.S. Patent No. 11,845,610, issued December 19, 2023, entitled “Automated Decant System”; U.S. Patent Publication No. 2021 / 0380343, published December 9, 2021, entitled “Robotic Each Picking in a Micro-Fulfillment Center”; and U.S. Patent No. 10,984,375, issued April 20, 2021, entitled “Picking Workstation with Mobile robots and Machine Vision Verification of Each TransfersAty. Docket No. 1127P017369- WO (PCT)Performed by Human Operators,” all of which are incorporated by reference herein in their entirety.

[0029] Fig. 5 shows a partial and simplified overhead view of a horizontal level 115 in the storage structure 102. This overhead view shows aisles 106 with storage locations 104 to either side of the aisle 106. It further shows a mobile robot 128 that can traverse the aisles 106 along tracks 107 and can access the storage locations 104. The mobile robot 128 can also travel along decks 108 to allow it to turn and to allow it to exit one aisle 106 and enter a different one.

[0030] In accordance with the present disclosure a mobile robot 128 is configured to transport a tote carrying at least one product, and a storage structure 102 accessible by the mobile robot 128. The storage structure 102 may include multiple horizontal levels 115, each offset vertically from an adjacent horizontal level, and an aisle 106 extending through the storage structure 102. The aisle 106 may include: tracks 107 extending along a length of the aisle 106 and along which the mobile robot 128 travels, and climbing channels 105 (also referred to as channels, vertical channels, or level changing channels) each extending along a height of the aisle 106 and along which the mobile robot 128 travels to move vertically from one horizontal level 115 to another horizontal level of the storage structure 102. The storage structure 102 may include storage locations 104 accessible by the mobile robot 128 from each of multiple horizontal levels 115.

[0031] Figs. 6-9 show some examples of static catwalks that may be used in the storage structure 102. As shown in the catwalk 130 in Fig. 6, it is generally contemplated that each static catwalk is composed of multiple catwalk sections (or segments) 132 that are vertically spaced from adjacent catwalk sections 132. Each catwalk section 132 is at a horizontal level 115, and mobile robots 128 move along tracks 107 at the same horizontal level 115. The catwalk sections 132 may be adjacent to and / or directly underneath tracks 107 utilized by the mobile robots 128. A static catwalk 130 generally includes static sections 132 that do not change their positions, in contrast to a dynamic section that is configured to dynamically change its position (such as by opening and closing a horizontal barrier). Although Figs. 6-9 (and the other figures) show examples of static catwalks, it should be understood that, in accordance with the present disclosure, the system / facility 100 and / or storage structure 102 may include a combination of static and dynamic catwalks.Aty. Docket No. 1127P017369- WO (PCT)

[0032] The catwalk 130 is configured to support a person’s weight and to allow the person to traverse at least a portion of the length of the aisle 106. The catwalk sections 132 are each statically disposed at aisles 106 at two or more horizontal levels 115 and extend along the length of an aisle 106 at the corresponding horizontal level 115. Each section 132 is shorter than the length of the aisle 106 at the corresponding horizontal level 115. Horizontally adjacent sections 132 are arranged with a vertical gap between them that is greater than the height of a mobile robot 128 transporting a tote and less than a vertical distance between two adjacent horizontal levels 115. It is generally contemplated that this vertical gap will allow horizontal movement of mobile robots 128 along the horizontal level 115, while also providing a relatively short step down or step up for a person. As addressed further below, this vertical staggering of catwalk sections 132 allows mobile robots 128 to move vertically. Otherwise, a planar catwalk extending along the entire length of a horizontal level 115 would completely block vertical movement of the mobile robots 128.

[0033] Fig. 6 shows two static catwalks 130 with a short, staggered design. As can be seen, in Fig. 6, there is an upper static catwalk I 30A and a lower static catwalk 130B. Each catwalk 130 is composed of catwalk sections 132 that alternate back and forth between two different horizontal levels 115, i.e., the catwalk sections 132 are staggered between the two levels 115. It is contemplated that each section 132 may be relatively short in length, which may require the use of more sections 132 to form the complete catwalk 130. The length of each section 132 may be roughly equivalent to, or comparable to, the distance between two climbing channels 105.

[0034] In Fig. 6, the upper static catwalk 130A and the lower static catwalks BOB are structurally arranged in the same manner, i.e., the sections 132 have the same relationship to other sections in the catwalk 130. It should be understood that the length and number of catwalk sections 132 used may be tailored to the circumstances and / or to the dimensions of the storage structure 102. The length of each section 132 may be roughly equivalent to the distance defined by two adjacent climbing channels 105; although, each section may have any suitable length.

[0035] Still referring to Fig. 6, one end of one catwalk section 132A may overlap with one end of a horizontally adjacent catwalks section 132B, and an opposite end of the one section 132A and an opposite end of the horizontally adjacent section 132B may extend in opposite directions. TheAty. Docket No. 1127P017369- WO (PCT) overlapping arrangement of horizontally adjacent sections 132 may prevent the formation of a gap through which an individual might fall. In other words, the horizontally adjacent sections 132 of the catwalk 130 may be arranged without a horizontal gap. The horizontally adjacent sections 132 of the catwalk 130 may be staggered with the vertical gap. The overlap between horizontally adjacent sections 132 may be disposed outside of the climbing channels 105.

[0036] The vertical gap may be configured to allow a user to move from one section 132A to a horizontally adjacent section 132B with a single step. The vertical gap may be 14 to 18 inches (or 35.56 cm to 45.72 cm); although, the vertical gap may have any suitable size. This vertical gap may be selected so that the vertical gap is large enough to allow mobile robots to move through the gap but small enough so that it is below, or within the parameters of, any required safety regulation (such as governmental safety regulations). In other words, the size of the vertical gap may be sufficiently large for mobile robots to pass through but may be sufficiently small to promote safety for individuals.

[0037] The catwalk sections 132 may allow positioning of incapacitated or damaged mobile robots 128 to facilitate safety and / or maintenance. For example, an incapacitated mobile robot 128 may be pushed by another, functional mobile robot 128 so that it is under a catwalk section 132. This positioning may allow an individual to safely walk about or otherwise access the incapacitated mobile robot 128. Alternatively, or in addition, an incapacitated or damaged mobile robot 128 may be pushed horizontally from a position that is not on a catwalk section 132 to a nearby catwalk section 132 so that it may be accessed and repaired by a maintenance technician.

[0038] Fig. 7 shows another example of a catwalk 134 but with an offset short, staggered design. The catwalk 134 in Fig. 7 is generally the same as the one in Fig. 6, but the upper catwalk 134A has been offset in the horizontal direction relative to the lower catwalk 134B. In other words, with respect to an imaginary vertical line drawn in Fig. 7, a lower section 136A of the upper catwalk 134A corresponds to an upper section 136B of the lower catwalk 134B.

[0039] Fig. 8 shows an example of several catwalks 138 with a staircase design. As can be seen, as one moves from left to right, the catwalk 138 descends with each catwalk section 140 one level lower than the preceding catwalk section 140. In other words, for an individual moving from left to right on the catwalk 138, it is comparable to descending a staircase. Each section 140 of theAty. Docket No. 1127P017369- WO (PCT) catwalk 138 is arranged to be one level lower along the length of the aisle 106. This descending staircase design may allow an individual to push an incapacitated mobile robot 128 to the next catwalk section 140 without moving the mobile robot 128 vertically upward. Of course, the staircase design could be ascending from left to right, in which each subsequent section 140 is one level higher than the preceding one.

[0040] Fig. 9 shows an example of a catwalk 142 with a large, staggered design. This catwalk 142 is generally similar to the one shown in Fig. 6 but with longer sections 144. Again, in this example, there is an upper static catwalk 142A and a lower static catwalk 142B. The catwalk sections 144 of each catwalk 142 alternate back and forth between two different horizontal levels 115, i.e., the catwalk sections 144 are staggered between the two levels 115. Each section 144 may be relatively long in length, which may require the use of fewer sections 144 to form the complete catwalk 142. The length of each section 144 may be roughly equivalent to or greater than the distance defined by three or more adjacent climbing channels 105; although the each section may have any suitable length.

[0041] The static catwalks may be integrated with in-rack transit planes 108 (IRTPs), or decks. These IRTPs 108 may connect two adjacent storage structures 102. Mobile robots 128 may exit an aisle 106 onto an IRTP 108, and from the IRTP 108, may enter a different aisle in the same structure or in an adjacent structure. As described below, a catwalk may, in effect, use an IRTP 108 as a section of the catwalk.

[0042] Fig. 10 shows an example of a catwalk 146 that has been integrated with IRTPs 108. As can be seen, one or more sections of the catwalk 146 extend to and contact IRTP 108. More specifically, a first end of each IRTP 108 is connected to, or at the same horizontal level 115, as a first catwalk section 148. The combination of IRTP 108 and first catwalk section 148 may extend nearly the length defined by the distance between three adjacent climbing channels 105. In the upper catwalk 146A, a second catwalk section 150 is disposed a level below the second end of each IRTP 108, while in the lower catwalk 146B, the second catwalk section 150 is disposed a level above. More specifically, the second catwalk section 150 overlaps and fills the gap between the second end of an IRTP 108 and an end of a first catwalk section 148. The second catwalkAty. Docket No. 1127P017369- WO (PCT) section 150 may be shorter in length than the first one, and it may be disposed at a climbing channel 105.

[0043] Fig. 11 shows a catwalk 152 that has been integrated with IRTPs 108. As can be seen, two IRTPs 108 have been connected to, or are at the same horizontal level 115, as two first catwalk sections 154 in an alternating sequence. The combination of two IRTPs 108 and two first catwalk sections 154 extend nearly the length defined by five adjacent climbing channels 105. In the upper catwalk 152A, a second catwalk section 156 is disposed at a level below a gap between ends of the IRTP 108 and a first catwalk section 154, while in the lower catwalk 152B, the second catwalk section is disposed a level above. As should be understood, other ways of integrating catwalks with IRTPs are possible in which some catwalk sections may connect to, or are at the same horizontal level as IRTPS, while other catwalk sections may be a level above or below and fill in gaps.

[0044] This staggered arrangement of catwalk sections allows a mobile robot 128 to move vertically along the climbing channels 105. Without a staggered arrangement, vertical movement of mobile robots 128 would be blocked by a catwalk. In other words, if a catwalk extends the entire length of a horizontal level 115, mobile robots 128 will not be able to get around the catwalk to continue their upward or downward movement.

[0045] Figs. 12-14 show staggered arrangements of catwalk sections and the paths mobile robots 128 may take to move to reach a vertical destination. Fig. 12 generally shows a staircase design of catwalk sections 158. On the left side of the figure, a first path 160 is shown where a mobile robot 128 may alternate between vertical movements along climbing channels 105 and horizontal movements between catwalk sections 158 at different horizontal levels 115 in a zigzag manner. The distance between catwalk sections 158 at different horizontal levels 115 is selected to allow the mobile robot 128 to fit between them. A second path 162 is shown that extends generally from the lower left portion of the figure to the upper right portion of the figure. Again, the mobile robot 128 travels along this second path by generally alternating between vertical movements along climbing channels 105 and horizontal movements along horizontal levels 115.

[0046] Figs. 13 and 14 show close-up, partial views of catwalks 164 and 166 having short, staggered designs. Fig. 13 shows a path 168 around a catwalk 164 for a mobile robot 128 in whichAty. Docket No. 1127P017369- WO (PCT) it moves vertically along a climbing channel 105 until it is blocked by a catwalk section 169, then it moves horizontally between catwalk sections 169 to an adjacent climbing channel 105, then it moves vertically upwardly until blocked again, and then it repeats this zigzagging process. Similarly, Fig. 14 shows an upward path 170 for a mobile robot 128 around a catwalk 166. When the mobile robot 128 moves vertically and encounters a catwalk section 172, it moves horizontally to an adjacent climbing channel 105 to continue upward movement until blocked. It continues with this zigzag approach until it reaches the desired horizontal level 115. In other words, the mobile robot 128 is configured to move from one climbing channel 105 to another climbing channel 105 via the tracks 107. In the event that there is a section of the catwalk 164 and 166 that blocks a directed vertical movement of the mobile robot 128 from one horizontal level 115 to an adjacent horizontal level 115 via the one climbing channel 105.

[0047] It is generally contemplated that the system / facility 100 may generally include additional features to promote interaction between mobile robots 128 and humans. The mobile robot 128 may include a radio frequency identification tag configured to provide information regarding the location of the mobile robot 128. This feature may facilitate routing of the mobile robot 128 along the horizontal levels 115 and the climbing channels 105 to a desired destination. This feature may help determine the status and position of a mobile robot 128 that may be damaged or otherwise incapacitated so as to allow a person to move to its location and attempt to repair or remove it. Other tracking devices and sensors may also be used to establish the location of a mobile robot 128 as it moves through the system / facility 100.

[0048] The order fulfillment system / facility 100 may include certain safety features. For example, the mobile robot 128 may be configured to pause or alter its path when a human is detected within an aisle 106. The system 100 may be arranged to redirect mobile robots 128 elsewhere in case of an anomaly involving a damaged or incapacitated mobile robot 128. Some scenarios of mishaps may require an individual, such as a technician, to physically enter a portion of the system 100 to address the mobile robot 128. In this instance, the system / facility 100 may be shut down partially or completely to ensure the safety of the individual, i.e., mobile robots 128 may be redirected to other portions of the facility 100 and / or may be blocked from entering the area by the damaged or incapacitated mobile robot 128.Aty. Docket No. 1127P017369- WO (PCT)

[0049] Fig. 15 shows a process 200 of order fulfillment using mobile robots. It is generally contemplated that the facility has multiple pathways along which mobile robots move horizontally and vertically. It is generally contemplated that the facility also has static catwalk sections to facilitate human movement. It is generally contemplated that the process 200 involves static catwalks and catwalk sections, such as described above. The process 200 may use some or all of the various types of catwalks and components described above.

[0050] At block 202, a current location of a mobile robot configured to transport a tote carrying products is determined. For example, the current location of the mobile robot may be determined by identifying the location of the mobile robot using a radio frequency identification tag or in any other suitable manner. It is contemplated that other tracking devices and / or sensors may be used to determine the mobile robot’s location. The mobile robot may be remotely guided by an individual or control system to a desired destination; however, it is contemplated that the mobile robot may move and navigate autonomously or semi-autonomously such that its location need not be determined in order for the mobile robot to move to a desired destination.

[0051] At block 204, the mobile robot is routed within a storage structure to retrieve and transport a tote carrying product(s). The mobile robot may be routed between multiple horizontal levels of the storage structure and that each horizontal level may be offset vertically from an adjacent horizontal level. The mobile robot travels via channels each establishing vertical paths between the multiple horizontal levels and along an aisle extending through the storage structure with the aisle including tracks extending along a length of the aisle and along which the mobile robot travels. The mobile robot may be remotely guided by an individual or control system to a desired destination. The mobile robot may act autonomously or semi-autonomously to route itself within the storage structure.

[0052] At block 206, the mobile robot is directed to move vertically along a first climbing channel. At block 208, it encounters a first catwalk section blocking upward movement along the first climbing channel. At block 210, it moves along tracks at a first horizontal level to an unobstructed, second climbing channel. At block 212, the mobile robot moves along the second climbing channel.Aty. Docket No. 1127P017369- WO (PCT)

[0053] In other words, the mobile robot may be directed to move vertically from one horizontal level to an adjacent horizontal level via one of the channels that provides a direct vertical path from the one horizontal level to the adjacent horizontal level when the direct vertical path is unobstructed by a catwalk, or portion thereof. However, when the direct vertical path is obstructed by a catwalk, or portion thereof, the mobile robot moves along a horizontal level until it reaches an unobstructed climbing channel where it can again proceed with its upward movement. In this manner, the mobile robot can move vertically upward (or downward) in a zigzag manner until it reaches the desired horizontal manner.

[0054] The catwalk, and portions thereof, are configured to support a weight of a human to allow the human to traverse at least a portion of the length of the aisle. Further, the catwalk includes sections each of which is statically disposed at aisles at two or more horizontal levels and extend along the length of an aisle at a corresponding horizontal level. Each section may be shorter than the length of the aisle at the corresponding horizontal level, and horizontally adjacent sections may be arranged with a vertical gap therebetween that is greater than a height of the mobile robot transporting the tote and less than a vertical distance between two adjacent horizontal levels of the multiple horizontal levels. In this way, the mobile robot may move through the vertical gap.

[0055] Optionally, as necessary, this movement of the mobile robot may be repeated as often as required to reach the desired horizontal level. At block 214, the mobile robot encounters a second catwalk section that blocks vertical movement along the second climbing channel. At block 216, it moves along tracks at a second horizontal level to an unobstructed, third climbing channel. At block 218, the mobile robot moves vertically along the third climbing channel. This zigzagging movement, i.e., alternating between vertical and horizontal movement, may be repeated, if necessary.

[0056] When the mobile robot reaches the desired horizontal level, the mobile robot may move along the aisle to a storage location where totes carrying products to be retrieved are stored. The mobile robot may then retrieve and transport a tote from that storage location. It may then use the process 200 described above to vertically navigate the storage structure and circumnavigate catwalk sections to its next destination.Aty. Docket No. 1127P017369- WO (PCT)

[0057] Optionally, at block 220, as a safety feature, if a human is detected within an aisle, the mobile robot may be directed to pause or alter its path. In some forms, it may be contemplated that operational mobile robots will generally not be present in areas where humans are present. However, in the event that operational mobile robots and individuals are present in the same area, the mobile robots would be directed to pause or alter their path.

[0058] Those skilled in the art will recognize that a wide variety of other modifications, alterations, and combinations can also be made with respect to the above-described embodiments without departing from the scope of the invention, and that such modifications, alterations, and combinations are to be viewed as being within the ambit of the inventive concept.

[0059] It should be understood that the foregoing description is only illustrative of the present disclosure. Various alternatives and modifications can be devised by those skilled in the art without departing from the present disclosure. Accordingly, the present disclosure is intended to embrace all such alternatives, modifications and variances that fall within the scope of any claims appended hereto. Further, the mere fact that different features are recited in mutually different dependent or independent claims does not indicate that a combination of these features cannot be advantageously used, such a combination remaining within the scope of the present disclosure.

[0060] What is claimed is:

Claims

Aty. Docket No. 1127P017369- WO (PCT)CLAIMS1. An order fulfillment system comprising: a mobile robot configured to transport a tote carrying at least one product; and a storage structure accessible by the mobile robot, wherein the storage structure comprises: multiple horizontal levels, each offset vertically from an adjacent horizontal level; an aisle extending through the storage structure, the aisle comprising: tracks extending along a length of the aisle and along which the mobile robot travels; and channels each extending along a height of the aisle and along which the mobile robot travels to move vertically from one horizontal level to another horizontal level of the storage structure; storage locations accessible by the mobile robot from each of multiple horizontal levels; and a catwalk configured to support a weight of a human to allow the human to traverse at least a portion of the length of the aisle, wherein the catwalk comprises sections each of which is statically disposed at aisles at two or more horizontal levels and extending along the length of an aisle at a corresponding horizontal level, wherein each section is shorter than the length of the aisle at the corresponding horizontal level, and wherein horizontally adjacent sections are arranged with a vertical gap therebetween that is greater than a height of the mobile robot transporting the tote and less than a vertical distance between two adjacent horizontal levels of the multiple horizontal levels.

2. The system of claim 1, wherein one end of one section of the catwalk overlaps with one end of a horizontally adjacent section of the catwalk, and an opposite end of the one section and an opposite end of the horizontally adjacent section extend in opposite directions.Aty. Docket No. 1127P017369- WO (PCT)3. The system of claim 1, wherein an overlap between the horizontally adjacent sections is disposed out of the channels.

4. The system of claim 1, wherein the horizontally adjacent sections of the catwalk are arranged without a horizontal gap.

5. The system of claim 1, wherein the horizontally adjacent sections of the catwalk are staggered with the vertical gap.

6. The system of claim 1, wherein each section of the catwalk is arranged to be one level lower along the length of the aisle.

7. The system of claim 1, wherein the vertical gap is configured to allow a user to move from one section to a horizontally adjacent section with a single step.

8. The system of claim 1, wherein the vertical gap is 14 to 18 inches (or 35.56 cm to 45.72 cm).

9. The system of claim 1, a length of one or more sections of the catwalk are greater than a distance between two or more adjacent channels.

10. The system of claim 1, one or more sections of the catwalk extend to and contact IRTPs.

11. The system of claim 1, the mobile robot is configured to move from one channel to another channel via the tracks in the event that there is a section of the catwalk that blocks a directed vertical movement of the mobile robot from one horizontal level to an adjacent horizontal level via the one channel.

12. The system of claim 1, wherein the mobile robot comprises a radio frequency identification tag configured to provide information of a location of the mobile robot.

13. The system of claim 1, wherein the mobile robot is configured to pause or alter its path when a human is detected within the aisle.

14. The system of claim 1, wherein the catwalk does not comprise a dynamic section configured to dynamically change its position.Aty. Docket No. 1127P017369- WO (PCT)15. A method of order fulfillment, the method comprising: determining a current location of a mobile robot configured to transport a tote carrying products; and routing the mobile robot within a storage structure to retrieve and transport a tote carrying at least one product between multiple horizontal levels, each offset vertically from an adjacent horizontal level, via channels each establishing vertical paths between the multiple horizontal levels and along an aisle extending through the storage structure, the aisle comprising tracks extending along a length of the aisle and along which the mobile robot travels, wherein the step of routing the mobile robot comprises directing the mobile robot to move vertically from one horizontal level to an adjacent horizontal level via one of the channels that provides a direct vertical path from the one horizontal level to the adjacent horizontal level, wherein the direct vertical path is unobstructed by a catwalk configured to support a weight of a human to allow the human to traverse at least a portion of the length of the aisle, wherein the catwalk comprises sections each of which is statically disposed at aisles at two or more horizontal levels and extending along the length of an aisle at a corresponding horizontal level, wherein each section is shorter than the length of the aisle at the corresponding horizontal level, and wherein horizontally adjacent sections are arranged with a vertical gap therebetween that is greater than a height of the mobile robot transporting the tote and less than a vertical distance between two adjacent horizontal levels of the multiple horizontal levels.

16. The method of claim 15, wherein the step of routing the mobile robot comprises directing the mobile robot to move from one channel to another channel via the tracks in the event that there is a section of the catwalk that blocks a directed vertical movement of the mobile robot from the one horizontal level to the adjacent horizontal level via the one channel.

17. The method of claim 15, wherein the step of determining the current location of the mobile robot includes identifying a location of the mobile robot using a radio frequency identification tag.

18. The method of claim 15 further comprising directing the mobile robot to pause or alter its path when a human is detected within the aisle.Aty. Docket No. 1127P017369- WO (PCT)19. The method of claim 15, wherein the horizontally adjacent sections of the catwalk are staggered with the vertical gap.20 The method of claim 15, wherein each section of the catwalk is arranged to be one level lower along the length of the aisle.

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