Augmented aerial sortation

Embodiments herein describe a combined aerial and ground sortation system. That is, the system can include both an aerial sortation system and a ground sortation system that work together to sort items (e.g., packages) in a warehouse or building. In one embodiment, the combined aerial and ground sortation system includes a leading sorter that identifies which packages should be sorted using the aerial sortation system and which should be sorted by the ground sortation system. The aerial sortation system may use drones to fly the package to one of the containers and drop the package into the container while the ground sortation system may use drive units that move along a floor of the warehouse to deposit the packages into the container. In another embodiment, the aerial sortation system performs a first, primary sort of the items while the ground sortation system performs a secondary sort.

BACKGROUND

The present invention relates to combining aerial and ground sortation systems.

Currently, many warehouse sortation systems rely on ground based sortation where conveyors, associates, or autonomous vehicles transport items to different locations in the warehouse (e.g., different containers or locations). As a result, sorting the items is limited to the space provided by the floor of the warehouse. For example, an associate or autonomous vehicle must often navigate through narrow aisles and chock points that experience significant portions of traffic. These physical limitations restrict the throughput of the sortation process. Without additional space to maneuver, adding more associates or autonomous vehicles to the sortation process has limited effect on its throughput.

DETAILED DESCRIPTION

Embodiments herein describe a combined aerial and ground sortation system. That is, the system can include both an aerial sortation system and a ground sortation system that work together to sort items (e.g., packages) in a warehouse or building. As discussed above, a ground sortation system that relies on conveyors, associates, or autonomous vehicles (e.g., drive units) to move packages through the warehouse is limited by the floor space of the warehouse. However, an aerial sortation system that includes drones can move in the space above the floor thereby changing the sortation process from a 2D process, which is limited to the space on the floor, to a 3D process that includes the total volume of the warehouse. The throughput of the sortation process can increase dramatically since the sortation process is no longer limited to a 2D space.

In one embodiment, the combined aerial and ground sortation system includes a leading sorter that identifies which packages should be sorted using the aerial sortation system and which should be sorted by the ground sortation system. For example, the leading sorter may use the weight, size, aerodynamic properties, packaging type, and the like to determine whether the package should be sorted using the aerial or ground sortation system. Further, the aerial and ground sortation systems may sort the packages to the same containers or locations, where each container or location corresponds to a specific geographic area such as a zip code, another warehouse, delivery route, etc. For example, the aerial sortation system may use drones to fly the package to one of the containers and drop the package into the container while the ground sortation system may use drive units that move along a floor of the warehouse until reaching one of the containers and eject the package into the container. Because the drive units operate on the floor while the drones operate in the airspace above the floor, the aerial and ground sortation systems can work seamlessly together to sort packages to the same (shared) containers or locations.

In another embodiment, the aerial sortation system performs a first (e.g., primary) sort of the items while the ground sortation system performs a second (e.g., secondary) sort. In this combined aerial and ground sortation system, the drones of the aerial sortation system may fly the packages to different containers and drop the items into a container corresponding to the item's destination. Once a container is full, the drive units in the ground sortation system can retrieve the full container and move it to a desired shipping location. The drive units can also move a new, empty container into the position vacated by the full container. In this manner, the aerial performs a first sort by moving packages into one of a plurality of containers while the ground sortation system performs a second sort by moving full containers to designated shipping locations.

FIG.1illustrates a combined aerial and ground sortation system in a warehouse100, according to one embodiment described herein. As shown, the warehouse100includes a conveyor105A (e.g., a conveyor belt or a plurality of powered rollers) for receiving packages150that are sorted into containers145in a sortation area140. The packages150may have different weights, sizes, textures, etc. which determine whether the packages150are sorted by an aerial sortation system that includes drones125or a ground sortation system that includes drive units130. To determine which system sorts the packages150, the warehouse100includes a leading sorter110that performs an initial (or coarse) sort of the packages150. The leading sorter110can include scales, package scanners, barcode readers and the like for identifying different physical characteristics of the incoming packages150such as weight, dimensions, texture of outer surface, and the like. For example, packages150with a weight above a threshold may be sorted by the ground sortation system, while packages150with weights below the threshold are sorted using the aerial sortation system. Further, even if packages150have weights below the threshold, the leading sorter110may route these packages to the ground sortation system if one or more dimensions of the package is too large (e.g., above a threshold) or based on the shape of the package (e.g., a cube rather than an envelope). The texture of the package150may also affect whether it is sorted by the drones125or the drive units130.

In one embodiment, rather than determining the physical characteristics of each package150using the leading sorter110, these characteristics may have been identified previously, e.g., when items were placed in the packages150. In that scenario, the leading sorter110may use a barcode or image scanner to identify the package150and then retrieve its previously determining physical characteristics from a database.

After deciding which sortation system should receive the package150, the leading sorter110can include any number of mechanical actuators for routing the packages150accordingly. For example, the leading sorter110can include pushers, pneumatic systems, slides, robotic arms, and the like for placing the packages150on either a conveyor105B that guides packages150to a ground loader115or a conveyor150C that guides the packages150to an air loader120.

The ground loader115includes a mechanical system for loading packages150received on the conveyor105B onto the drive units130, while the air loader120includes a mechanical system for loading package150received using the conveyor105C onto the drones125. In one embodiment, the air loader120and the ground loader115detect when packages are successfully loaded onto the drones125or the drive units130without human intervention. In addition to loading the packages150on the drones125and drive units130, the ground and air loaders115,120can include charging stations or ports for charging batteries or super capacitors on the drones125and drive units130.

In one embodiment, the drive units130includes a conveyor belt135for receiving and depositing (e.g., ejecting) the packages150into the containers145in the sortation area140. For example, to load a package150, the ground loader115may use a conveyor belt or other actuator to move a package150onto the conveyor belt135of the drive unit130. In parallel, the drive unit130can activate the conveyor belt135to move the package150to a stable location on the unit130(e.g., a center of the conveyor belt135). However, the drive units130can use other means such as powered rollers or robotic arms to move packages150onto, and move packages off, the drive units130.

The drones125can include clasps, baskets, electromagnetic holders, and the like for carrying packages150. For example, the drones125may land, or hover over, the air loader120which attaches a package to a clasp or loads a package into a basket. The drone125can then release the clasp or tip the basket to unload the package.

In one embodiment, the drones125and drive units130are autonomous vehicles which can be steered or flown using central controllers, local controllers, or a mix of both. That is, the combined aerial and ground sortation system can use control systems (which can have centralized and local components) for navigating the drones125and drive units130through the warehouse100and loading/unloading the packages150. For example, the control system for the aerial sortation system may include a movement planning system with knowledge of the size of the drone and the size of the package, and makes intelligent path planning when a drone is laden to avoid hitting obstacles or other drones. A similar movement planning system can be used by the ground sortation system to ensure the drive units can navigate the floor without colliding with other drive units or obstacles.

In one embodiment, a central controller for the aerial sortation system communicates with a central controller for the ground sortation system in order to synchronize actions between the drones125and the drive units130. However, in other embodiments, the aerial and ground sortation systems may operate independently of each other. That is, these systems may be designed so that the aerial sortation system can be added to an existing ground sortation system without requiring any operational or functional changes to the operation of the ground sortation system.

InFIG.1, the drones125and drive units130move the packages from the respective loaders115,120to the containers145in the sortation area140. The containers145may be boxes, gaylords, bins, shelves, and the like. In one embodiment, the containers145may be recessed in the floor so that the drive units130and drones125can both deposit packages150into the containers. In another embodiment, there may be ramps up to the containers145which the drive units130can climb in order to deposit the packages150into the containers145. In yet another embodiment, there may be elevators on the sides of the containers145on which the drive units130deposit the packages150. The elevators can then lift up the packages150so they can be deposited into the raised containers145. In any case, the drones125and the drive units130can sort the packages150into the same share containers145. However, in another embodiment, they may sort the packages150into different containers145. For example, a subset of the containers145may be designed to receive packages150transported by the drive units130while another subset is designed to receive packages transported by the drones125.

InFIG.1, the drive unit130A has received a package150B from the ground loader115and is transporting the package150B to a corresponding container145. A control system may instruct the drive unit130A where to deposit the package150B based on a final or intermediate destination of the package150B—e.g., a zip code, city, delivery route, a different warehouse, etc. The drive unit130B, on the other hand, is returning to the ground loader115to retrieve a different package after previously depositing a package into a container145in the sortation area140. Similarly, the drone125A is carrying a package150A from the air loader120to one of the containers145using an intermediate or final destination of the package150A. WhileFIG.1illustrates the drone125A and the drive unit130A carrying single packages, in other embodiments, each of these vehicles may carry multiple packages that are deposited in the same container145or multiple containers145. On the other hand, the drone125B is returning to the air loader120from the sortation area140to retrieve another package (or packages). As used herein, a vehicle that is currently carrying a package150or item for sortation is referred to as a laden vehicle, while a vehicle without a package is an unladen vehicle.

The combined aerial and ground sortation system also includes drive units160that move the containers145from the sortation area140to docking stations165. The docking stations165are locations where the containers145(and the packages therein) can be retrieved and removed from the warehouse100. For example, the packages150may be loaded onto a truck or retrieved by a delivery person to be delivered to a customer. The drive units160may also move empty containers145into the sortation area140to replace the full containers145that have been removed. In other embodiments, instead of using autonomous drive units160to move the containers145into and out of the sortation area140, associates may move the containers using a hand truck or forklift.

In embodiments discussed below, instead of the drones125and the drive units130sorting packages into the containers145, only the drones125may move the packages150into the sortation area140. In that scenario, the leading sorter110could be omitted since all the packages150would be delivered by the drones125. However, the drive units160could still be used to perform another (secondary) sort by moving the containers to their designated docking stations165.

WhileFIG.1illustrates using autonomous drive units130for transporting packages in the ground sortation system, in other embodiments, the warehouse100may use human operated vehicles or a system of conveyors (e.g., conveyor belts or powered rollers) to sort the packages150. For example, an associate may pick up one or more items using a fork lift, hand truck, etc. and move the items to sortation area140to deposit the items in their corresponding containers145as discussed above. If conveyors are instead used, the conveyor can include actuators such as pushers, slides, or pneumatic systems to route packages from the ground loader115to the containers145.

FIG.2illustrates a combined aerial and ground sortation system in a warehouse200, according to one embodiment described herein. The warehouse200includes a lower floor205on which a mezzanine210is supported. The raise mezzanine210provides a surface that the drive units130can use to sort packages into multiple chutes215in the mezzanine210.FIG.2illustrates a side view of the mezzanine210so that the structures beneath the chutes215A and215B are visible. As shown, spiral slides220are coupled at a top end to the chutes215A and215B while the bottom ends of the slides220terminate at respective containers145. As shown, the drive unit130A is depositing a package150into the chute215C. That package150then travels down the spiral slide (not shown) underneath the chute215C until being deposited into a container. Providing the raised mezzanine210results in being able to recess the containers beneath the drive units130which makes it easier for the drive units130to deposit packages into the containers145. Further, while slides are shown, they are not necessary and the drive units130could deposit the packages through the chutes215and directly into the containers145. The use of the slides220may depend on the height of the mezzanine210above the lower floor205.

InFIG.2, the drones125also deposit packages into the same chutes215and containers145used by the drive units130. As shown, the drone125A has just released a package into the chute215A. This package travels down the slide220and into the container145just like packages that are ejected into the chute215by the drive units130. In addition, the chutes215contain respective guides225which help to ensure packages dropped by the drones125end up in the chute. For example, the size of the guides225may be larger than the size of the chutes215which make it easier for the drones125to accurately release packages onto the guides225, especially for lightweight objects (e.g., envelopes) which might not drop straight down when released by a drone125. Moreover, aiming for the guides225may mean the drones125can release packages150from higher altitudes, thereby keeping the drones125farther above the mezzanine210. The guides225may be funnels or slides which direct the packages into the chute215. Further, the guides225can serve as backstops when transitioning packages from the drive units130to the chutes215so the drive units130can eject packages150from multiple directions. If the package is ejected with a velocity that causes the packages to overshoot the chute215, the package may instead land on the guide225which then urges the package into the chute215and onto the slide220.

The warehouse200uses a multi-story loading area (or stacked loading area) for loading packages onto the drive units130and the drones125. In this example, the ground loader115is on the same plane as the mezzanine210so that the drive units130can move seamlessly between the mezzanine210and the ground loader115to receive packages or to charge. The ground loader115is connected to the conveyor105B to receive packages from the leading sorter, which is not shown inFIG.2. The air loader120, in contrast, is stacked above the ground loader115so that the air loader120is above the mezzanine210. Raising the air load120permits the drones125to retrieve the packages without worrying about interference with the drive units130. Like the ground loader115, the air loader120is connected to the leading sorter110using the conveyor105C.

In one embodiment, the airspace above the mezzanine210can be divided into different layers for air traffic. For example, a lower level (or slice) of the airspace may be used by the drones125to transport packages from the air loader120to the chutes215. After depositing a package, the drones125may move to a upper level of the airspace that is above the lower level to move back towards the air loader120. Because the drones125are now unladen, moving to an upper level requires less power, and thus, using an upper level as the “return” level may be more power efficient. That way, the airspace can be divided into levels used by the drones125which can reduce congestion and improve throughput of the sortation system. In other embodiments, the airspace may be divided into more than two levels where each level has a designated purpose. For example, one level may be used by laden drones125to deliver packages to one half of the chutes215or containers145, a second level used by laden drones125to deliver packages to the other half of the chutes215or containers145, and a third level is used by unladen drones125returning to the air loader120.

In one embodiment, the drones125can be equipped with a bumper ring or other expansion apparatus that is larger than the openings formed by the chutes215so that faulted drones125do not fall down into the chutes215.

InFIG.2, the chutes215and containers145are shared by the drones125and the drive units130. However, this is not a requirement, and instead some of the chutes215may be used by drive units130while other chutes215are used by the drones125. Further, although not shown, separate drive units may be used on the lower floor205to switch out full containers145with new containers.

FIG.3is a flowchart of a method300for sorting items using containers shared by aerial and ground sortation systems, according to one embodiment described herein. In one embodiment, the method300is performed in the combined aerial and ground sortation system illustrated inFIG.2. At block305, a leading sorter sorts items between aerial and ground based sortation systems. The leading sort can consider physical properties of the items such as weight, size, shape, texture, aerodynamic properties, and the like to determine whether the item is better suited to being sorted by the aerial sortation system or the ground sortation system. The various structures and arrangements of the leading sorter is described in more detail inFIG.1.

At block310, the aerial based sortation system sorts the items into a plurality of shared containers. The aerial sortation system includes an air loader for loading packages onto the drones using, e.g., fasteners, clips, clasps, baskets, hangers, etc. These holding elements are controllable by the drone so that when the drone arrives at the destination container for the item, the drone can release the holding element so the item is deposited into the container.

In one embodiment, the drones include a battery or a super capacitor for powering the drone. While batteries can hold much higher charges than a super capacitor which can sustain powered flight for longer, they are also much heavier. If a drone makes short trips (with low weight items) before returning to the air loader, it may be more efficient to use super capacitors which are recharged more frequently (e.g., each time the drone returns to the air loader to retrieve a new package). However, if a drone makes long trips (or delivers multiple packages before returning to the air loader) or carries heavier items, a battery may be preferred. Further, the drones may be charged at the same time new packages are being loaded onto the drones.

At block315, the ground based sortation system sorts the items into the plurality of shared containers. That is, the drive units, conveyors, or human operated apparatuses implemented in the ground sortation system can use the same containers to sort items as the aerial sortation system. Referring toFIG.2, both the drive units130and the drones125use the same chutes215to deposit packages into the containers145. Thus, if the warehouse200already includes the ground sortation system comprising the ground loader115, the drive units130, and the mezzanine210, the air loader120and the drones125could be added without having a significant or any impact on the ground sortation system. In fact, the aerial and ground sortation systems could act independent of each other. That is, the control system for the ground sortation system can instruct the drive units130to sort packages into the shared containers145without having to communicate with (or coordinate with) the control system of the aerial sortation system. The drive units130and the drones125can sort the packages in parallel without having to coordinate their actions.

However, in other embodiments, the aerial and ground sortation system can coordinate some actions. For example, if the drive unit130C and the drone125A both attempt to deposit packages into the chute215A at the same time, the packages may be stuck, or one package may knock the other package onto the mezzanine so it does not fall through the chute215A. In that case, the control system may communicate so that the drone125A or the drive unit130C waits for the other vehicle to deposit its package first. Thus, some coordination or communication between the aerial and ground sortation systems may be desired.

FIG.4illustrates a chute215shared by aerial and ground sortation systems, according to one embodiment described herein. In one embodiment,FIG.4illustrates one of the chutes215which may be used in the mezzanine210illustrated inFIG.2. As shown, the chute215defines an aperture through which packages150can be deposited by the drones125in the aerial sortation system and the drive units130in the ground sortation system.

In this example,FIG.4includes an enclosure410with a first end that terminates (or connects to) a funnel405and a second end that terminates in the chute215. The funnel405provides a receptacle for receiving packages that are dropped by the drones125. That is, to deposit the package150B into the chute215, the drone125moves so that it is above the funnel405. In one embodiment, the funnel405may be a larger opening than the chute215. Even if the funnel405is smaller than the chute215, the funnel405is still advantageous since the sortation system does not need to worry about the drive unit130ejecting the package150A into the chute215at the same time as the drone125drops the package150B. Instead, the aerial sortation system can use the funnel405to deposit packages into the chute215while at the same time the ground sortation system uses the portion of the chute215not occupied by the enclosure410. Doing so may reduce or eliminate coordination between the two systems—i.e., the systems can operate independent of each other.

Further, the funnel405may have perforation or holes to increase the airflow through the funnel as the drone flies above it. That is, the funnel405can have high porosity to reduce turbulent airflow caused by a drone flying over the funnel405. For example, the surface can have holes large enough to reduce turbulence, but small enough to prevent packages150from slipping through the holes rather than being directed into the enclosure410. Moreover, adding perforation to a surface to reduce turbulence can be applied to other surfaces in the warehouse which interact with the drones125such as surfaces at the air loader, charging station, home station, and the like.

In one embodiment, the funnel405(or the guides225inFIG.2) is designed to cushion packages that are released from the drones. The surface of the funnel405may be soft or be supported by springs or shock absorbers that enable the surface of the funnel405to give as the packages150land. In another example, the funnel405can include a positive air system that pushes air up through holes in the surface where the packages land to create an air cushion above the surface that can reduce the velocity of the packages150before they land on the funnel405(or the guide225).

Packages150deposited into the funnel405are guided into the enclosure410which, in this embodiment, is an annular (e.g., rectangular) shape that is angled or vertical so that packages are directed from the funnel405to the chute215. While the enclosure410does not need to be enclosed on all sides, doing so may mitigate the risk that a package falls off the enclosure410before reaching the chute215. In other embodiments, the enclosure410may be a slide attached the funnel405which has a sliding surface with side walls, but with no top.

FIG.5illustrates a combined aerial and ground sortation system, according to one embodiment described herein.FIG.5illustrates a warehouse100that includes an air loader120for inducting and loading packages onto the drones125. In this embodiment, the aerial sortation system is solely responsible for sorting received packages into the containers145. That is, unlike inFIG.2where drive units and drones both sort packages into the containers145, inFIG.5only the drones125sort packages into the containers145. Put differently, the drones125perform a primary sort based on the intermediate or final destination of the packages.

When a container145is full or it is time to deliver the packages (even if the container145is not full), the ground sortation system can instruct a drive unit160to retrieve the container145from the sortation area140. As shown inFIG.5, the drive unit160B has retrieved the container145A and is moving the container145A to the docking station165B. There, the container145can be loaded into a truck or the packages may be removed so they can be moved to a different warehouse or delivered to customers. In this manner, the drive units160perform a secondary sort where containers145are moved to a docking station165that corresponds to the destination of the packages in the containers. That is, each container may hold packages that have the same destination (e.g., same zip code, neighborhood, delivery route, destination warehouse, etc.). The drive units160sort the container145by moving it to another location in the warehouse500that corresponds to the destination of the packages in the container.

FIG.5also illustrates the drive unit160A moving an empty container145B into the sortation area140to, e.g., replace the container145A which was removed. In this example, the containers145are specialized containers that can be lifted and moved by the drive units160so that drive units160can continue to remove and add containers145in the sortation area140. For example, the containers145may include legs through which the drive units160can move until they are directly underneath the containers145. The drive units160can then raise a platform to lift the legs off the ground so that the containers145can be moved out of the sortation area140. However, this is just one non-limiting technique that can be used to perform the secondary sort.

The drive units160can also rearrange the containers so that more popular, or more frequently used containers, are moved to locations in the sortation area that are closer to the air loader. For example, the drones may sort twice as many packages for a first zip code than a second zip code. If the container for the second zip code is closer to the air loader, the drive units160may swap the two containers so that the container for the first zip code is closer to the air loader. This reduces the overall flight time of the drones which can mean they recharge less and also increases overall throughput in the warehouse.

FIG.6is a flowchart of a method600for performing different sorts using aerial and ground sortation systems, according to one embodiment described herein. At block605, the aerial sortation system performs a primary sort to sort items into a plurality of containers using drones. In one embodiment, the aerial sortation system uses drones to sort packages between an induct station (e.g., an air loader) to a sortation area that can include a plurality of containers or receptacles.

At block610, the combined aerial and ground sortation systems determines whether a container is full (or if it is time for a container to be delivered). For example, the sortation system may determine whether a container is full based on summing the total volume of the packages placed in the container. In another example, the warehouse may include an overhead vision system to captures images of the container, or use cameras mounted on the underside of the drones, to determine when a container is full. If so, the method600proceeds to block615where the ground sortation system performs a secondary sort to move the container to a corresponding destination (e.g., a shared destination of the packages in container). The ground sortation system can use autonomous vehicles such as the drive units160inFIG.5to move the containers, or instruct associates to move the containers using, e.g., hand trucks or forklifts. In addition to removing the containers, the ground sortation system can ensure new containers are moved into the sortation area.

Because the aerial sortation system relies on the ground sortation system to move out containers ready to be delivered and replace them with new containers, the two sortation systems may communicate. For example, the control system for the ground sortation system may determine when a container is full or needs to be delivered. This control system can instruct the aerial sortation system to temporarily stop sorting packages to the container. This provides the ground sortation system time to move the full container out of the sortation area and replace it with an empty container. Once done, the ground sortation system can inform the aerial sortation system it can begin sorting packages into the container.

FIG.7illustrates a fixture705for transporting multiple packages150using a drone125, according to one embodiment described herein. As shown, the fixture705(e.g., a hanging apparatus) has at least one attachment point to the drone125, but may be attached to the drone125at multiple attachment points. The fixture705also includes multiple clasps710A-F that can hold the packages150A-F. In one embodiment, the clasps710are individually controllable by the drone125. That is, when the drone125determines it is over a location (e.g., a container) where the package150A should be deposited, the drone125can release the clasp710A while keeping the other clasps710B-F engaged so that only the package150A is released.

Further, to improve weight distribution, the drone125may deliver the packages150A-F in a manner so that the drone125does not become unbalanced. For example, the drone125may first deliver the package150A, then the package150F, then the package150B, then the package150E, and so forth. Doing so may improve the charge life of the drone125and help it maintain a steady flight pattern.

In one embodiment, the packages150may be loaded according to weight. For example, lighter packages may be attached at the ends (e.g., to clasps710A and710F) while heavier packages are attached closer to the middle (e.g., clasps710C and710D). In addition to considering weight, the packages150may be attached to the clasps710based on aerodynamic properties of the packages150. For example, the packages150may be arranged so that a skinner side is facing the direction the drone travels to reduce air resistance.

When depositing the packages150onto a target (e.g., a container, guide, or funnel), the drone125may consider the location of the package150relative to the target. For example, if the drone125is going to release the package150A into a container, rather than centering the drone125above the center of the container, the drone125instead centers the location of the package150A (which is offset from the center of the drone125) over the center of the container. Thus, the drone125can consider the locations of the packages150on the fixture705to align the packages150with the target.

In one embodiment, the same machine that packages items to form the packages150also attaches the packages150onto the feature. That is, rather than an air loader receiving individual items that then are attached to the drone125, the air loader may receive the fixture705which already has the packages150pre-loaded. The air loader then attaches the fixture705to the drone125. For example, the same machines used enclose and seal items into padded envelopes may be outfitted to attach the padded envelopes to the fixture705. These fixtures705can then be transported to the air loader which attaches the fixtures705to the drones125for delivery.

When performing a multi-package mission, the charge of the drone's power source may fall below a safety threshold before the drone125has delivered all the packages150. In that case, the drone125may return to a charging station to recharge while still being laden with packages. In one embodiment, the charging station removes the undelivered packages and returns them to the air loader where they can be loaded onto another drone for delivery. Alternatively, the drone may keep the packages while being charged. For example, if charging takes only a few seconds or minutes (e.g., to charge a high capacitance capacitor), it may be more efficient to leave the packages attached to the charging drone which can then finish the mission once charged. Moreover, in another embodiment, the drone performing a multi-package mission may recharge during the mission. For example, the warehouse may include charging stations in the sortation area which the drones can use as waystations to charge during multi-package missions.

FIG.8illustrates a safety system in a warehouse800for a combined aerial and ground sortation system, according to one embodiment described herein. The safety system includes overhead barriers810A and810B (e.g., chain linked fences) that are raised above the mezzanine210to form walkways815for an associate820. The overhead barriers810can protect the associate820from anything that may fall from the drone airspace805. Thus, an associate820can move in the walkways815to perform maintenance such as fixing faulty drive units130or drones125, or collect packages that might have not fallen in the chutes215.

Because the warehouse800also includes the drive units130which may move in the walkways815when sorting packages into the chutes215, the safety system also includes drive unit overrides825(e.g., override devices) that can be worn by the associate820. The drive unit overrides825can emit wireless signals (e.g., RF signals limited to a short distance such as 5-20 meters) that when received by the drive units130instruct the drive units130to perform a safety protocol such as moving in a direction away from the associate820or to stop moving until the drive unit override825is no longer in wireless range (e.g., the associate820has moved away from the region around the drive unit130. In addition to causing the drive units130to enter into a safety protocol, the drive unit override825can also emit RF signals that override the mission of the drones125to cause them to perform a safety protocol. For example, if a drone125receives the RF signals, it may move a predetermined distance away from the associate820or move to a predetermined altitude and remain stationary until the RF signal is no longer received (or until its battery/super capacitor level falls below a certain level which forces the drone to return to a charging station).

In one embodiment, the RF signals emitted by the override825are different depending on whether the associate is interacting with the ground sortation system or the aerial sortation system. If the associate is in a space used by the ground sortation system, the override825emits RF signals in a first mode that cause the drive units130to perform a safety protocol but any drones125within wireless range continue to operate as normal. That is, the drones125ignore the RF signal. Conversely, if the associate is in a space used by the drones125, the override825may emit RF signals in a second mode that instruct the drones125to perform the safety protocol while any drive units130receiving those signals can continue to operate normally. Further, the override825can operate in a third mode where the emitted RF signals cause both drones125and drive units130in wireless range to perform a safety protocol.

The safety system could also include no fly zones in the drone airspace805to prevent the drones125from ever flying into specific areas in the warehouse800such as a HVAC duct or flying outside a predefined drone area.

The safety system may also include sound isolation to protect associates820from noise generated by flying large numbers of drones125in a sortation area. In addition to wearing personal sound dampening equipment, the barriers810and the surface of the mezzanine may include sound dampening material. In yet another embodiment, the air loader can include sound dampening equipment and material. For example, associates may be tasked with attaching a package (or packages) onto a drone. As such, the associates may be exposed to significant drone noise. Sound dampening material may mitigate this noise exposure.