Patent Publication Number: US-2022212812-A1

Title: Translating drive devices, systems and methods for cargo handling system

Description:
FIELD 
     The present disclosure relates generally to cargo handling systems and, more particularly, to translating drive devices, systems, and methods for cargo handling systems. 
     BACKGROUND 
     Cargo handling systems for aircraft typically include various tracks and rollers disposed on a cargo deck that spans the length of a cargo compartment. Cargo may be loaded from an entrance of the aircraft and transported by the cargo system to forward or aft locations, depending upon the configuration of the aircraft. Cargo handling systems, such as, for example, those used on aircraft for transport of heavy containerized cargo or pallets, also referred to herein as unit load devices (ULDs), typically include fixed traction motors located throughout the doorway and longitudinal areas of a cargo compartment. 
     SUMMARY 
     A translating drive unit (TDU) is disclosed herein. The TDU may comprise: a housing; a plurality of guide rollers coupled to the housing; a drive system coupled to the housing, the drive system configured to translate the housing in a longitudinal direction; and a retractable pawl coupled to the housing. 
     In various embodiments, the drive system may include: a first gear extending outward from a first lateral side of the housing, and a second gear extending outward from a second lateral side of the housing. The plurality of guide rollers may include a first vertical roller disposed on the first lateral side of the housing, a second vertical roller disposed on the second lateral side of the housing, and a first horizontal roller disposed between the first vertical roller and the second vertical roller. The plurality of guide rollers may further comprise: a third vertical roller disposed on the first lateral side of the housing and spaced apart longitudinally from the first vertical roller; a fourth vertical roller disposed on the second lateral side of the housing and spaced apart longitudinally from the second vertical roller; and a second horizontal roller spaced apart longitudinally from the first horizontal roller. The TDU may further comprise a power source disposed within the housing. The power source may be a plurality of cells disposed within the housing. The retractable pawl may be pivotably coupled to the housing. The TDU may further comprise a first cable disposed at a first longitudinal end of the housing. The TDU may further comprise a coupling mechanism disposed at a second longitudinal end of the housing, the coupling mechanism configured to couple the TDU to a second cable of an adjacent TDU. 
     A translating drive unit (TDU) is disclosed herein. The TDU may comprise: a housing; a drive system operably coupled to the housing; a retractable pawl operably coupled to the housing; and a controller operable to: command the drive system to translate the TDU longitudinally along a cargo compartment; and command the retractable pawl to transition from a retracted state to an extended state, the extended state having the retractable pawl disposed vertically above a surface of the housing. 
     In various embodiments, the TDU may further comprise a sensor, wherein the sensor comprises at least one of a unit load device (ULD) sensor disposed on the surface of the housing and a light detection and ranging (LiDAR) sensor. The controller may further be operable to receive from the ULD sensor an indication whether a ULD is disposed above the TDU. The drive system may further comprise a first gear extending outward from a first lateral side of the housing and a second gear extending outward from a second lateral side of the housing. The controller may further be operable to command the first gear and the second gear to rotate and translate the TDU longitudinally along the cargo compartment. The TDU may further comprise a coupling mechanism disposed at a first longitudinal end of the housing and a cable disposed at a second longitudinal end of the housing. The controller may further be operable to command the coupling mechanism to actuate to couple the TDU to an adjacent TDU. 
     A translating drive system for a cargo handling system is disclosed herein. The translating drive system may comprise: a first roller tray having a first plurality of rollers disposed therein, the first roller tray extending longitudinally through a cargo compartment; a second roller tray having a second plurality of roller disposed therein, the second roller tray spaced apart laterally from the first roller tray; a first translating drive unit (TDU) disposed between the first roller tray and the second roller tray, the first TDU having a first retractable pawl configured to extend above a first surface of a housing of the TDU, the first TDU including a first drive system configured to translate the first TDU longitudinally through the cargo compartment; and a second TDU disposed between the first roller tray and the second roller tray and spaced apart longitudinally from the first TDU, the second TDU including a second retractable pawl configured to extend above a second surface of the housing of the first TDU, the second TDU including a second drive system configured to translate the second TDU longitudinally through the cargo compartment. 
     In various embodiments, the first TDU may be configured to couple to the second TDU via a coupling mechanism and cable. The first TDU may include a first transceiver and the second TDU includes a second transceiver. The translating drive system may comprise a main controller, wherein the first TDU is configured to receive instructions through the first transceiver from the main controller, and wherein the second TDU is configured to receive instructions through the second transceiver from the main controller. 
     The forgoing features and elements may be combined in various combinations without exclusivity, unless expressly indicated herein otherwise. These features and elements as well as the operation of the disclosed embodiments will become more apparent in light of the following description and accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The subject matter of the present disclosure is particularly pointed out and distinctly claimed in the concluding portion of the specification. A more complete understanding of the present disclosure, however, may best be obtained by referring to the following detailed description and claims in connection with the following drawings. While the drawings illustrate various embodiments employing the principles described herein, the drawings do not limit the scope of the claims. 
         FIGS. 1A and 1B  illustrate schematic views of a cargo handling system, in accordance with various embodiments; 
         FIG. 2  illustrates a portion of a cargo handling system with a translating drive system, in accordance with various embodiments; 
         FIG. 3  illustrates a portion of a cargo handling system with a translating drive system, in accordance with various embodiments; 
         FIG. 4  illustrates a portion of a cargo handling system with a translating drive system, in accordance with various embodiments; 
         FIG. 5  illustrates a portion of a cargo handling system with a translating drive system, in accordance with various embodiments; 
         FIG. 6  illustrates a top down view of a translating drive unit (TDU), in accordance with various embodiments; 
         FIG. 7  illustrates a bottom up view of a TDU, in accordance with various embodiments; 
         FIG. 8A  illustrates a perspective view of a TDU, in accordance with various embodiments; 
         FIG. 8B  illustrates a perspective view of a TDU, in accordance with various embodiments; 
         FIG. 9  illustrates a portion of a translating drive system, in accordance with various embodiments; 
         FIG. 10A  illustrates a portion of a TDU, in accordance with various embodiments; 
         FIG. 10B  illustrates a portion of a TDU, in accordance with various embodiments; 
         FIG. 11A  illustrates a portion of a TDU, in accordance with various embodiments; 
         FIG. 11B  illustrates a portion of a TDU, in accordance with various embodiments 
         FIG. 12A  illustrates a first TDU coupled to a second TDU, in accordance with various embodiments; 
         FIG. 12B  illustrates a first TDU coupled to a second TDU, in accordance with various embodiments; 
         FIG. 13  illustrates a perspective view of a TDU, in accordance with various embodiments; 
         FIG. 14  illustrates a perspective view of a TDU with a portion of the housing hidden for clarity, in accordance with various embodiments; 
         FIG. 15  illustrates a control system for a translating drive system, in accordance with various embodiments; and 
         FIG. 16  illustrates a control system for a TDU, in accordance with various embodiments. 
     
    
    
     DETAILED DESCRIPTION 
     The following detailed description of various embodiments herein makes reference to the accompanying drawings, which show various embodiments by way of illustration. While these various embodiments are described in sufficient detail to enable those skilled in the art to practice the disclosure, it should be understood that other embodiments may be realized and that changes may be made without departing from the scope of the disclosure. Thus, the detailed description herein is presented for purposes of illustration only and not of limitation. Furthermore, any reference to singular includes plural embodiments, and any reference to more than one component or step may include a singular embodiment or step. Also, any reference to attached, fixed, connected, or the like may include permanent, removable, temporary, partial, full or any other possible attachment option. Additionally, any reference to without contact (or similar phrases) may also include reduced contact or minimal contact. It should also be understood that unless specifically stated otherwise, references to “a,” “an” or “the” may include one or more than one and that reference to an item in the singular may also include the item in the plural. Further, all ranges may include upper and lower values and all ranges and ratio limits disclosed herein may be combined. 
     With reference to  FIGS. 1A and 1B , a schematic view of an aircraft  10  having a cargo deck  12  located within a cargo compartment  14  is illustrated, in accordance with various embodiments. The aircraft  10  may comprise a cargo load door  16  located, for example, at a forward end of the aircraft  10  and configured to rotate upward (as illustrated in  FIG. 1A ) or sideways to expose an opening  18  that provides access to the cargo compartment  14 . In various embodiments, a second cargo load door  17  may be located at other portions of the aircraft  10 , such as, for example, at an aft end of the aircraft  10  and configured to rotate downward (as illustrated in  FIG. 1B ) and provide a second opening  19  to gain access to the cargo compartment  14 . Inside the cargo compartment  14 , one or more trays  20 , e.g., a first tray  22  and a second tray  24 , extend generally from the fore end of the aircraft  10  to the aft end of the aircraft  10 . As described more fully below, the one or more trays  20  provide a support structure for which a platform  26  may transit along a length of the aircraft  10  between the fore end and the aft end and carry a ULD or some other form of cargo carrier, such as, for example, a container of a size typically used for ocean-going transport by ship or truck. Without loss of generality, a cargo load  28  of any size or shape, which may include objects within containers or ULDs or objects not within containers or ULDs, such as, for example, automobiles or the like, will be considered herein as configured for transport on the platform  26 . 
     Still referring to  FIGS. 1A and 1B , in various embodiments, the one or more trays  20 , during loading or unloading of the cargo load  28 , may be connected to a loading structure  30  which, in various embodiments, may comprise one or more trays  32  that correspond to the one or more trays  20  extending along the cargo deck  12  of the aircraft  10 . In various embodiments, the loading structure  30  may be attached to an elevated structure, such as, for example, a truck  34  (as illustrated in  FIG. 1B ) or a scissor lift or a loading dock or the like, such that the one or more trays  20  and the loading structure  30  are located substantially at the same elevation and configured to transition a platform  26  either onto or off from the one or more trays  20 . For example, a first cargo load  36  may be transitioned from the loading structure  30 , through the opening  18  and onto the one or more trays  20 , and then along the one or more trays  20  to the aft end of the aircraft, where the first cargo load is secured for transport. A second cargo load  38  may be followed by a third cargo load  40  and so on until the cargo deck  12  is filled to a desired capacity with cargo. After the aircraft  10  has reached its destination, each cargo load, such as, for example, the first cargo load  36 , the second cargo load  38  and the third cargo load  40  are unloaded from the aircraft  10  in similar fashion, but in a reverse sequence to the loading procedure. To ensure cargo loads are restrained, the aircraft  10  may include a restraint assembly as described herein and in accordance with various embodiments. 
     Typical cargo handling systems may include multiple fixed Power Drive Units (PDUs), which rely on friction to provide ULD drive force. Having a cargo handling system with a drive system based on friction may make it difficult to achieve traction under wet and/or other adverse conditions. A friction interface may also result in wear of both a drive tire for a respective PDU, as well as a baseplate for a respective ULD. 
     A minimum number of PDUs for a typical cargo handling system may be a function of length and size of a cargo compartment and dimensions of a base plate for a respective ULD. Other factors that may drive the quantity of PDUs in a typical cargo handling system may be duty cycle limitations of a respective PDU, drive force capability of a respective PDU, redundancy of PDUs to affect system level characteristics for schedule interrupt. Each of these factors may combine to drive weight and cost into a typical cargo handling system. 
     Additionally, typical cargo handling systems with fixed PDUs that are located closer to the doorway area may experience a greater usage, and thus an amount of wear, relative to the fixed PDUs disposed towards an end of the cargo compartment. In this regard, a typical cargo handling system with fixed PDUs may have a greater number of fixed PDUs proximate the doorway to account for wear during the life of the typical cargo handling system, driving weight and cost into the typical cargo handling system and/or derivative platforms of typical cargo handling systems. 
     Additionally, typical cargo handling systems with fixed PDUs may be hard wired into the cargo handling system, which may involve a high level of system integration between a typical cargo handling sub-system and an aircraft platform, further driving cost and time for development of a typical cargo handling system. 
     Disclosed herein, in accordance with various embodiments, is an autonomous translating drive system having at least two translating drive units (TDUs). In various embodiments, a TDU in the autonomous translating drive system may include an independent power source, such as a battery or the like. In various embodiments, the autonomous translating drive system may include any linear actuator system. For example, the translating drive system may include a rack and pinion drive system, a chain drive system, a belt drive system, a rigid chain system, a rigid belt system, or the like. 
     In various embodiments, the autonomous translating drive system may include a first TDU and a second TDU. In various embodiments, the first TDU and the second TDU may be in electronic communication with each other. In various embodiments, the first TDU and the second TDU may be in electronic communication with a controller. In various embodiments, the first TDU and the second TDU may be configured to engage a ULD and translate the ULD longitudinally through a cargo compartment of an aircraft (e.g., cargo compartment  14  from  FIGS. 1A and 1B ). In various embodiments, the first TDU and the second TDU may each include a first drive gear and a second drive gear, each drive gear configured to interface with a rack (e.g., a rack disposed on a lateral surface of a roller tray (e.g., the one or more trays  20  of cargo deck  12  from  FIGS. 1A and 1B ). 
     Referring now to  FIG. 2 , a portion of a cargo handling system  100  having a translating drive system  200  is illustrated, in accordance with various embodiments. The cargo handling system  100  is illustrated with reference to an XYZ coordinate system, with the X-direction extending longitudinally in an aft direction (and defining a longitudinal direction), the Y-direction extending perpendicular to the X-direction (and defining a lateral direction) and the Z-direction extending vertically, each direction being with respect to an aircraft in which the cargo handling system  100  is positioned, such as, for example, the aircraft  10  described above with reference to  FIGS. 1A and 1B . 
     In various embodiments, the cargo handling system  100  may define a first tray  110  extending longitudinally in the aft direction (i.e., the X-direction) and a second tray  120  extending longitudinally in the aft direction (i.e., the X-direction). The first tray  110  and the second tray  120  may be spaced apart laterally (i.e., the Y-direction) from each other. The first tray  110  may include a first plurality of rollers  112 , and the second tray  120  may include a second plurality of rollers  122 . Each roller in the first tray  110  extends laterally from a first lateral side of the first tray  110  to a second lateral side of the first tray  110 . Similarly, each roller in the second tray  120  extends laterally from a first lateral side of the second tray  120  to a second lateral side of the second tray  120 . 
     In various embodiments, the translating drive system  200  includes a first TDU  210  and a second TDU  220 . The first TDU  210  may be spaced apart longitudinally (i.e., the X-direction) from the second TDU  220 . In various embodiments, the first TDU  210  is configured to couple to the second TDU  220 , as described further herein. In various embodiments, the first TDU  210  includes a first retractable pawl  212  and the second TDU  220  includes a second retractable pawl  222 . In various embodiments, the first TDU  210  and the second TDU  220  may be configured to provide a clamping force (i.e., between the first retractable pawl  212  and the second retractable pawl  222 ) to a respective ULD and translate the respective ULD longitudinally along the first plurality of rollers  112  and the second plurality of rollers  122 . 
     In various embodiments, the first TDU  210  may be configured to couple the first TDU  210  to a longitudinally adjacent TDU (e.g., the second TDU  220 ). For example, if additional force for translating and/or controlling a ULD is detected/determined by the first TDU  210 , or a controller, the first TDU  210  may be coupled to the second TDU  220  via a cable  214 . In various embodiments, the cable  214  may be stowed in the first TDU  210  in response to not being in use (i.e., when the first TDU  210  is uncoupled from an adjacent TDU), as described further herein. 
     In various embodiments, the first TDU  210  and the second TDU  220  may be configured to operate independently of one another. For example, with brief reference to  FIG. 3 , the first TDU  210  in an un-coupled state is illustrated, in accordance with various embodiments. In the un-coupled state, the cable  214  may be stowed at least partially in a housing  216  of the first TDU  210  by any method known in the art, such as coiled, or the like. In various embodiments, the first TDU  210  may be configured to translate a ULD longitudinally along the first plurality of rollers  112  and the second plurality of rollers  122  alone. For example, the first retractable pawl  212  of the first TDU  210  is configured to interface with a side of a ULD and the first TDU  210  is configured to translate longitudinally and push the ULD at a ULD/retractable pawl interface, in accordance with various embodiments, as described further herein. 
     Referring now to  FIGS. 4 and 5 , any number of TDUs may be utilized to translate a cargo unit (e.g., a ULD  402 ) in accordance with various embodiments. For example, as shown in  FIG. 4 , a single TDU (e.g., first TDU  210 ) may push the ULD  402  on a first side of the ULD  402  in a longitudinal direction (e.g., the X-direction) during loading or unloading. Similarly, as shown in  FIG. 5 , the first TDU  210  and the second TDU  220  may be configured to clamp the ULD  402  longitudinally (e.g., in the X-direction) to control the forward and aft sides of the ULD  402 . In this regard, with two TDUs, as shown in  FIG. 5 , the translating drive system  200  may provide greater control of the ULD  402  in the forward and aft directions and/or provide greater force in response to a single TDU being unable to provide enough force to translate the ULD  402 , in accordance with various embodiments. 
     In various embodiments, TDUs may also be disposed at lateral sides of the ULD. In this regard, the additional TDUs may provide lateral stability to the ULD  402 , in accordance with various embodiments. 
     Referring now to  FIGS. 6 and 7 , a top down view ( FIG. 6 ) and a bottom up view ( FIG. 7 ) of a TDU  600 , in accordance with various embodiments, is illustrated. In various embodiments, the first TDU  210  and the second TDU  220  from  FIGS. 2-5  may be in accordance with the TDU  600 . In various embodiments, each TDU in a translating drive system (e.g., translating drive system  200  from  FIG. 2 ) may be in accordance with the TDU  600 . 
     The TDU  600  comprises a housing  610  and a retractable pawl  620 . In various embodiments, the housing  610  includes a slot  612  disposed therethrough. In various embodiments, the slot  612  includes the retractable pawl  620  disposed therein. In various embodiments, the retractable pawl  620  is configured to extend vertically above a first surface  614  of the housing (e.g., a top surface). In various embodiments, the retractable pawl  620  may pivot about a pivot point and extend above the first surface  614 . Although described herein as being pivotably coupled, the retractable pawl  620  may extend above the first surface  614  by any method known in the art, such as being hingedly coupled, slidingly coupled, or the like. 
     In various embodiments, the retractable pawl  620  may be actuated by an electric motor, spring loaded in either an extracted or retracted state, or the like. In various embodiments, the retractable pawl may include a manual release to disengage as a fail-safe for the TDU  600 . In various embodiments, the retractable pawl  620  may further comprise a mating component for a cable, such as a hook or the like, as described further herein. The mating component may be configured to be coupled to a cable (e.g., cable  214  from  FIG. 2 . In various embodiments, the mating component may be coupled to a cable of a cargo handling system, such as a winch or the like, to pull the TDU and in turn pull the ULD (e.g., ULD  402  from  FIGS. 4 and 5 ). 
     In various embodiments, the TDU  600  further comprises a drive system  630 . In various embodiments, the drive system  630  of the TDU  600  is configured to propel the TDU in a longitudinal direction (e.g., the X-direction) between trays (e.g., trays  110 ,  120  from  FIG. 2 ). Although described herein as including a rack and pinion drive system, the TDU  600  is not limited in this regard. For example, the drive system  630  may include a chain drive system, a belt drive system, a rigid chain system, a rigid belt system, or the like. 
     In various embodiments, the drive system  630  comprises a first gear  632 . Although illustrated as also including a second gear  634 , the present disclosure is not limited in this regard. For example, the drive system  630  may be configured to include only a single gear (e.g., first gear  632 ) on a first lateral side, and a roller disposed on an opposite lateral side, in accordance with various embodiments. The first gear  632  may be disposed on a first lateral side of the housing  610 , and the second gear  634  may be disposed on a second lateral side of the housing  610 , the second lateral side being opposite the first lateral side. The first gear  632  and the second gear  634  of the TDU  600  may be configured to interface with a rack (e.g., rack  114  of roller tray  110  from  FIG. 3 ). In various embodiments, the rack  114  from  FIG. 3  may comprise vertical pins, lateral slots, or the like. 
     In various embodiments, the TDU  600  may further comprise a plurality of guide rollers  640 . In various embodiments, the plurality of guide rollers  640  are configured to guide the TDU  600  between adjacent trays (e.g., trays  110 ,  120  from  FIG. 2 ) of a cargo handling system (e.g., cargo handling system  100  from  FIG. 2 ). In various embodiments, the plurality of guide rollers  640  may include a first vertical roller  641 , a second vertical roller  642 , and a horizontal roller  643 . In various embodiments, the first vertical roller  641  is disposed on a first lateral side of the housing  610  in a recess of a second surface  616  (e.g., a bottom surface) disposed opposite the first surface  614 . Similarly, the second vertical roller  642  is disposed on a second lateral side of the housing  610  in a recess of the second surface  616 , the second lateral side being opposite the first lateral side. In various embodiments, the horizontal roller  643  is disposed laterally between the first vertical roller  641  and the second vertical roller  642  in a recess of the second surface  616 . In various embodiments, the vertical rollers  641 ,  642  are configured to interface with lateral sides of trays (e.g., trays  110 ,  120  from  FIG. 2 ) in a cargo handling system  100  from  FIG. 2  for guiding the TDU  600  laterally between the trays and ensure the drive system  630  remains on track. In various embodiments, the first horizontal roller  643  is configured to ensure the TDU  600  translates with ease on a cargo deck of a cargo compartment (e.g., cargo compartment  14  from  FIG. 1A ). 
     In various embodiments, the first vertical roller  641 , the second vertical roller  642 , and the first horizontal roller  643  may be disposed at a first longitudinal end of the TDU  600 , and a third vertical roller  644 , a fourth vertical roller  645 , and a second horizontal roller  646  of the plurality of guide rollers  640  may be disposed at a second longitudinal end opposite the first longitudinal end. In various embodiments, the third vertical roller  644 , the fourth vertical roller  645  and the second horizontal roller  646  may be in the same orientation as the first vertical roller  641 , the second vertical roller  642 , and the first horizontal roller  643  described previously herein. 
     Although illustrated, and described, herein as including two sets of vertical guide rollers and horizontal guide rollers, the present disclosure is not limited in this regard, For example, the TDU  600  could include a single set of guide rollers (e.g., vertical rollers  641 ,  642  and horizontal roller  643 ), two sets of guide rollers (e.g., first set of guide rollers  641 ,  642 ,  643  and second set of guide rollers  644 ,  645 ,  646 ), or multiple sets of guide rollers (e.g., greater than 2 sets of guide rollers). 
     In various embodiments, the TDU  600  further comprises a cable  650  and a coupling mechanism  660 . In various embodiments, the cable  650  may be in a stowed position as illustrated in  FIGS. 6 and 7  when the cable  650  is not in use. In various embodiments, the cable  650  may be configured to be coupled to an adjacent TDU (e.g., first TDU  210  being coupled to second TDU  220  from  FIG. 2 ) via a coupling mechanism of the adjacent TDU (e.g., the coupling mechanism  660 ) in  FIG. 6 . In various embodiments, the coupling mechanism  660  may include a hook  662  configured to actuate about a central axis from an unlocked position to a locked position around a loop fitting  652  disposed at an end of the cable  650 . Although illustrated as including an actuatable hook  662  and a loop fitting  652 , one skilled in the art may recognize various ways to couple the cable  650  to an adjacent TDU (e.g., a draft gear and a draw gear or any other automatic coupler known in the art). 
     Referring now to  FIGS. 8A and 8B , perspective views of the TDU  600  is illustrated, in accordance with various embodiments. In various embodiments, the gears  632 ,  634  may extend laterally outward from a respective lateral side of the housing  610 . In this regard, the gears  632 ,  634  may be partially disposed within the housing  610 . 
     In various embodiments, the TDU  600  further comprises a charging connector  670 . The charging connector  670  may be electrically coupled to a power source disposed within the housing  610 , as described further herein. In various embodiments, a power source of the TDU  600  may be charged via the charging connector  670  when the TDU  600  is not in use. Although illustrated as including a charging port, the TDU  600  may include a wireless charging system, in accordance with various embodiments. Although illustrated is including a charging connector  670  for recharging a power source, the present disclosure is not limited in this regard. For example, a replaceable power source, such as replaceable cells may be utilized as a power source, in accordance with various embodiments. 
     In various embodiments, the TDU  600  may further include a location detection system  680 . In various embodiments, the location detection system  680  may include an electronic device  682 , such as a radio frequency identification (RFID) reader, a camera, a position sensor, or the like. In various embodiments, the position sensor may be any position sensor, such as a structured light, audio (radar), or a light detection and ranging (LiDAR) sensor. In this regard, the LiDAR sensor may be configured to provide absolute positional reference of the TDU  600  to a controller (e.g., an aircraft controller or a TDU controller), in accordance with various embodiments. In various embodiments, a LiDAR sensor may further be capable of detecting foreign object debris on a cargo deck and provide a fault indication to a respective controller. 
     In various embodiments, the electronic device  682  is configured to communicate with a corresponding fixed electronic device along the trays (e.g., trays  110 ,  120  from  FIG. 2 ) via a wireless protocol such as 802.11a/b/g/n/ac signal (e.g., Wi-Fi), a wireless communications protocol using short wavelength UHF radio waves and defined at least in part by IEEE 802.15.1 (e.g., the BLUETOOTH protocol maintained by Bluetooth Special Interest Group), a wireless communications protocol defined at least in part by IEEE 802.15.4 (e.g., the ZigBee protocol maintained by the ZigBee alliance), a cellular protocol, an infrared protocol, an optical protocol, a RFID protocol, a NFC protocol, or any other protocol capable of wireless transmissions. For example, with brief reference to  FIG. 9 , electronic devices  902  may be disposed on a lateral side of a tray  904  (e.g., trays  110 ,  120  from  FIG. 2 ). In various embodiments, the electronic devices  902  may be spaced apart longitudinally along the tray  904  and be configured to provide positional data (i.e., location data in the longitudinal direction of the cargo compartment). In various embodiments, the electronic device  682  of the location detection system  680  may be configured to receive location data from the electronic devices  902  of the tray  904  from  FIG. 9 . In various embodiments, the electronic devices  902  may include, for example, a RFID tag, a key fob, a near field communication (NFC) transmitter, or the like. 
     Referring now to  FIGS. 10A and 10B , a detail view of the coupling mechanism  660  of the TDU  600  is illustrated, in accordance with various embodiments. In various embodiments, the coupling mechanism  660  may be annular in shape and include an arcuate slot  1002  disposed therein. The arcuate slot  1002  may be configured to a receive a loop fitting (e.g., loop fitting  652 ), as described previously herein. For example, the coupling mechanism  660  may be configured to rotate about a centerline defined in a vertical direction, allowing the arcuate slot to be disposed outward from the second surface  616  (e.g., the bottom surface). In this regard, the arcuate slot  1002  may be configured to receive the loop fitting and close to a position illustrated in  FIGS. 10A and 10B , locking the loop fitting in the arcuate slot between the coupling mechanism  660  and the housing  610 , in accordance with various embodiments. 
     Referring now to  FIGS. 11A and 11B , a cable  650  in a stowed position ( FIG. 11A ), and a portion of the cable  650  coupled to and adjacent TDU ( FIG. 11B ) is illustrated, in accordance with various embodiments. In various embodiments, in the stowed position ( FIG. 11A ), the loop fitting  652  is disposed in a receptacle of the housing  610 . With combined reference to  FIGS. 11A and 10A /B, a protrusion  654  of the loop fitting  652  is configured to couple to the coupling mechanism  660  and be disposed between the arcuate slot  1002  of the coupling mechanism  660  and the housing  610  of the TDU  600  as illustrated in  FIGS. 12A and 12B , in accordance with various embodiments. Once coupled to an adjacent TDU, the cable  650  may be unwound based on a longitudinal length of a respective ULD and used to clamp the ULD and/or provide additional pulling force for translating the ULD. 
     Referring now to  FIG. 13 , the TDU  600  having a carrying handle  1302  is illustrated, in accordance with various embodiments. The carrying handle  1302  may be configured to allow an individual to remove the TDU  600  from a cargo deck after loading. For example, the TDUs disclosed herein may be removeable from the cargo handling system (e.g., cargo handling system  100  from  FIG. 2 ). In this regard, the TDUs may allow for additional weight to be disposed on an aircraft, since the weight of the TDUs would not be included during transport of cargo. In contrast, PDUs of typical cargo handling systems are fixed and/or add to the weight of a typical cargo handling system. 
     Referring now to  FIG. 14 , a perspective view of the TDU  600  is illustrated with a portion of the housing  610  not shown for clarity in accordance with various embodiments. In various embodiments, the TDU includes a power source (e.g., a plurality of cells  1402 ). Although illustrates as including a plurality of cells  1402  defining a battery for the TDU  600 , the present disclosure is not limited in this regard. For example, the power source may include a supercapacitor, a capacitor, or the like, in accordance with various embodiments. 
     Referring now to  FIG. 15 , a control system  1500  for a translating drive system (e.g., translating drive system  200  from  FIG. 2 , is illustrated, in accordance with various embodiments. In various embodiments, the control system  1500  may comprise a controller  1502  and a plurality of TDUs  600 . The controller  1502  may be in electronic communication with the plurality of TDUs  600  by any method known in the art. 
     In various embodiments, controller  1502  may be configured as a central network element or hub to access various systems and components of control system  1500 . In various embodiments, controller  1502  may comprise a processor. In various embodiments, controller  1502  may be implemented in a single processor. In various embodiments, controller  1502  may be implemented as and may include one or more processors and/or one or more tangible, non-transitory memories and be capable of implementing logic. Each processor can be a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof. Controller  1502  may comprise a processor configured to implement various logical operations in response to execution of instructions, for example, instructions stored on a non-transitory, tangible, computer-readable medium configured to communicate with controller  1502 . 
     System program instructions and/or controller instructions may be loaded onto a non-transitory, tangible computer-readable medium having instructions stored thereon that, in response to execution by a controller, cause the controller to perform various operations. The term “non-transitory” is to be understood to remove only propagating transitory signals per se from the claim scope and does not relinquish rights to all standard computer-readable media that are not only propagating transitory signals per se. Stated another way, the meaning of the term “non-transitory computer-readable medium” and “non-transitory computer-readable storage medium” should be construed to exclude only those types of transitory computer-readable media which were found in In Re Nuijten to fall outside the scope of patentable subject matter under 35 U.S.C. § 101. 
     In various embodiments, the controller  1502  may be configured to provide instructions to the plurality of TDUs  600 . In this regard, the controller  1502  may command a first TDU (e.g., first TDU  210  from  FIG. 2 ) to translate a first ULD to a first location of a cargo compartment (e.g., an aft end of a respective cargo compartment). In various embodiments, a second TDU (e.g., second TDU  220 ) may be instructed to translate a second ULD to a second location of a respective cargo compartment, or to combine with the first TDU to translate the first ULD, as disclosed previously herein, in accordance with various embodiments. In various embodiments, the plurality of TDUs  600  may be configured to communicate with the controller and/or other TDUs in a respective translating drive system (e.g., translating drive system  200  from  FIG. 2 ). Although illustrated as including a main controller  1502 , the present disclosure is not limited in this regard. For example, a control system may include only a plurality of autonomous TDUs configured to communicate with each other remotely for loading and unloading of ULDs. 
     Referring now to  FIG. 16 , a control system  1600  for a TDU in the plurality of TDUs  600  of a translating drive system (e.g. translating drive system  200  from  FIG. 2 ), is illustrated in accordance with various embodiments. The control system  1600  may include a controller  1602 , a transceiver  1604 , the retractable pawl  620 , the drive system  630 , the coupling mechanism  660 , the location detection system  680 , a ULD sensor  690 , and a position sensor  1606 . With brief reference to  FIG. 6 , the ULD sensor  690  may be disposed on the first surface  614  (e.g., a top surface) of the housing  610 . In various embodiments, the TDU  600  may further include status indicators  692  disposed on the first surface  614  configured to indicate a power source status of the TDU  600  as illustrated in  FIG. 6 . 
     In various embodiments, controller  1602  may be configured as a central network element or hub to access various systems and components of control system  1600 . In various embodiments, controller  1602  may comprise a processor. In various embodiments, controller  1602  may be implemented in a single processor. In various embodiments, controller  1602  may be implemented as and may include one or more processors and/or one or more tangible, non-transitory memories and be capable of implementing logic. Each processor can be a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof. Controller  1602  may comprise a processor configured to implement various logical operations in response to execution of instructions, for example, instructions stored on a non-transitory, tangible, computer-readable medium configured to communicate with controller  1602 . 
     System program instructions and/or controller instructions may be loaded onto a non-transitory, tangible computer-readable medium having instructions stored thereon that, in response to execution by a controller, cause the controller to perform various operations. The term “non-transitory” is to be understood to remove only propagating transitory signals per se from the claim scope and does not relinquish rights to all standard computer-readable media that are not only propagating transitory signals per se. Stated another way, the meaning of the term “non-transitory computer-readable medium” and “non-transitory computer-readable storage medium” should be construed to exclude only those types of transitory computer-readable media which were found in In Re Nuijten to fall outside the scope of patentable subject matter under 35 U.S.C. § 101. 
     In various embodiments, the controller  1602  is in electronic communication with a transceiver  1604 . The transceiver  1604  may be in electronic communication with the controller  1502  by any method known in the art, such as via a network, a router, or the like. In various embodiments, the transceiver  1604  may receive instructions from the controller  1502  of the control system  1500  for the translating drive system  200  from  FIG. 2  and send the received instructions to the controller  1602  of the control system  1600  for a respective TDU  600 . In various embodiments, the transceiver  1604  may further send status information received from controller  1602  with regards to a position of a respective TDU (e.g., from location detection system  680 ), whether a ULD is disposed above the TDU (e.g., from the ULD sensor  690 ), whether an additional TDU is needed to translate a respective ULD (e.g., from the location detection system  680  remaining the same), or the like. 
     In various embodiments, the controller  1602  may send instructions to the coupling mechanism  660  to open to receive a loop fitting (e.g., loop fitting  652 ), as described previously herein. In various embodiments, the controller  1602  may instruct drive system  630  to translate longitudinally along a respective cargo deck (e.g., cargo deck  12  from  FIG. 1A ) in response to a ULD being disposed above the TDU (received from the ULD sensor  690 ) and the retractable pawl  620  being in an extracted position. 
     In various embodiments, the controller  1602  may be configured to extract and retract the retractable pawl  620 . In various embodiments, the controller  1602  may send instructions to the retractable pawl  620  to be extracted prior to use in translating a respective ULD and/or instruct the retractable pawl  620  to retract when not in use, or when the retractable pawl is not being used to translate a respective ULD via the retractable pawl  620  for the respective TDU. 
     In various embodiments, the controller  1602  is in electronic communication with the position sensor  1606 . In various embodiments, the position sensor  1606  may be configured to provide position data relative to the rest of a cargo compartment (e.g., cargo compartment  14  from  FIG. 1A ) and/or have the ability to determine foreign object debris on a cargo deck (e.g., cargo deck  12  from  FIG. 1A ). In various embodiments, the position sensor  1606  and the ULD sensor  690  may be utilized in combination by the controller  1602  to determine a velocity of the respective TDU, to determine if the TDU is moving relative to the compartment, and/or to determine if a ULD is moving relative to the TDU. 
     Benefits, other advantages, and solutions to problems have been described herein with regard to specific embodiments. Furthermore, the connecting lines shown in the various figures contained herein are intended to represent exemplary functional relationships and/or physical couplings between the various elements. It should be noted that many alternative or additional functional relationships or physical connections may be present in a practical system. However, the benefits, advantages, solutions to problems, and any elements that may cause any benefit, advantage, or solution to occur or become more pronounced are not to be construed as critical, required, or essential features or elements of the disclosure. The scope of the disclosure is accordingly to be limited by nothing other than the appended claims, in which reference to an element in the singular is not intended to mean “one and only one” unless explicitly so stated, but rather “one or more.” Moreover, where a phrase similar to “at least one of A, B, or C” is used in the claims, it is intended that the phrase be interpreted to mean that A alone may be present in an embodiment, B alone may be present in an embodiment, C alone may be present in an embodiment, or that any combination of the elements A, B and C may be present in a single embodiment; for example, A and B, A and C, B and C, or A and B and C. Different cross-hatching is used throughout the figures to denote different parts but not necessarily to denote the same or different materials. 
     Systems, methods and apparatus are provided herein. In the detailed description herein, references to “one embodiment,” “an embodiment,” “various embodiments,” etc., indicate that the embodiment described may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to affect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described. After reading the description, it will be apparent to one skilled in the relevant art(s) how to implement the disclosure in alternative embodiments. 
     Furthermore, no element, component, or method step in the present disclosure is intended to be dedicated to the public regardless of whether the element, component, or method step is explicitly recited in the claims. No claim element herein is to be construed under the provisions of 35 U.S.C. 112(f) unless the element is expressly recited using the phrase “means for.” As used herein, the terms “comprises,” “comprising,” or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. 
     Finally, it should be understood that any of the above described concepts can be used alone or in combination with any or all of the other above described concepts. Although various embodiments have been disclosed and described, one of ordinary skill in this art would recognize that certain modifications would come within the scope of this disclosure. Accordingly, the description is not intended to be exhaustive or to limit the principles described or illustrated herein to any precise form. Many modifications and variations are possible in light of the above teaching.