Patent Publication Number: US-11648676-B2

Title: Robotic system with a coordinated transfer mechanism

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
     This application is a continuation of U.S. patent application Ser. No. 16/824,673 filed Mar. 19, 2020, issued as U.S. Pat. No. 10,766,141 on Sep. 8, 2020, which claims the benefit of U.S. Provisional Patent Application Ser. No. 62/845,792, filed May 9, 2019, both of which are incorporated by reference herein in their entirety. 
    
    
     TECHNICAL FIELD 
     The present technology is directed generally to robotic systems and, more specifically, to systems, processes, and techniques for coordinating operations of multiple units. 
     BACKGROUND 
     With their ever-increasing performance and lowering cost, many robots (e.g., machines configured to automatically/autonomously execute physical actions) are now extensively used in various different fields. Robots, for example, can be used to execute various tasks (e.g., manipulate or transfer an object through space) in manufacturing and/or assembly, packing and/or packaging, transport and/or shipping, etc. In executing the tasks, the robots can replicate human actions, thereby replacing or reducing human involvements that are otherwise required to perform dangerous or repetitive tasks. 
     However, despite the technological advancements, robots often lack the sophistication necessary to duplicate human interactions required for executing larger and/or more complex tasks. Accordingly, there remains a need for improved techniques and systems for managing operations and/or interactions between robots. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is an illustration of an example environment in which a robotic system with a coordinated transfer mechanism may operate. 
         FIG.  2    is a block diagram illustrating the robotic system in accordance with one or more embodiments of the present technology. 
         FIG.  3    is a top view illustrating a first example transfer environment in accordance with one or more embodiments of the present technology. 
         FIGS.  4 A- 4 D  are top views illustrating a processing sequence for the first example transfer environment in accordance with one or more embodiments of the present technology. 
         FIG.  5 A  is a top view illustrating a second example transfer environment, and  FIG.  5 B  is a profile view illustrating the second example transfer environment, both in accordance with one or more embodiments of the present technology. 
         FIGS.  6 A- 6 D  are top views illustrating a processing sequence for the second example transfer environment in accordance with one or more embodiments of the present technology. 
         FIG.  6 E  is a flow diagram of a first example method for operating the robotic system  100  of  FIG.  1    in accordance with one or more embodiments of the present disclosure. 
         FIG.  7 A  is a top view illustrating a third example transfer environment, and  FIG.  7 B  is a profile view illustrating the third example transfer environment, both in accordance with one or more embodiments of the present technology. 
         FIGS.  8 A- 8 D  are top views illustrating a processing sequence for the third example transfer environment in accordance with one or more embodiments of the present technology. 
         FIG.  8 E  is a flow diagram of a second example method for operating the robotic system of  FIG.  1    in accordance with one or more embodiments of the present disclosure. 
         FIG.  9    is a top view illustrating a fourth example transfer environment in accordance with one or more embodiments of the present technology. 
         FIGS.  10 A- 10 D  are top views illustrating a processing sequence for the fourth example transfer environment in accordance with one or more embodiments of the present technology. 
         FIG.  10 E  is a flow diagram of a third example method for operating the robotic system of  FIG.  1    in accordance with one or more embodiments of the present disclosure. 
         FIGS.  11 A- 11 C  are perspective views of example transfer trays in accordance with one or more embodiments of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Systems and methods for a robotic system with a coordinated transfer mechanism are described herein. The robotic system (e.g., an integrated system of devices that each execute one or more designated tasks) configured in accordance with some embodiments autonomously executes integrated tasks by coordinating operations of multiple units (e.g., robots). In some embodiments, an integrated task can include transferring object from one location to another. For example, in response to a shipping order that includes a specific set of items/objects, the robotic system can pick the ordered items from one or more sources (e.g., containers) and place them into a destination (e.g., a shipping container). 
     As described in detail below, in some embodiments, the robotic system can include/operate a picking robot that picks the objects from the source and packs them onto the destination. In some embodiments, the robotic system can include/operate a picking robot to pick the objects and place them on a transfer tray configured to laterally transfer the objects between the source and the destination. For example, the transfer tray can be adjacent to the source and/or the destination and/or laterally transfer the objects from over/adjacent to the source to over/adjacent to the destination. The robotic system can include a stopper configured to contact the objects on the source while the tray continues moving, thereby causing the objects to slide off the tray and drop onto the destination. The stoppers can be configured to contact the objects while the tray moves away from or towards the source. In some embodiments, the robotic system can include a packing robot that picks the objects from the transfer tray and places them onto the destination. 
     Further, in some embodiments, the transfer robots can include an end-effector (e.g., a gripper) that has a set of suction cups. The suction cups can be operated and/or activated individually to grip objects having various sizes, shapes, contours, and/or surface characteristics. In some embodiments, the transfer tray can include a belt conveyor transfer tray, a slotted transfer tray, and/or a perforated surface transfer tray. In some embodiments, the robotic system can include/operate one or more flexible gripper that is attached to a link via a joint. The flexible gripper can further include a locking mechanism and/or an actuator. In some embodiments, the robotic system can include a position adjustment mechanism configured to adjust position/pose of objects before picking and/or after packing operations. Details are described below. 
     In the following, numerous specific details are set forth to provide a thorough understanding of the presently disclosed technology. In other embodiments, the techniques introduced here can be practiced without these specific details. In other instances, well-known features, such as specific functions or routines, are not described in detail in order to avoid unnecessarily obscuring the present disclosure. References in this description to “an embodiment,” “one embodiment,” or the like mean that a particular feature, structure, material, or characteristic being described is included in at least one embodiment of the present disclosure. Thus, the appearances of such phrases in this specification do not necessarily all refer to the same embodiment. On the other hand, such references are not necessarily mutually exclusive either. Furthermore, the particular features, structures, materials, or characteristics can be combined in any suitable manner in one or more embodiments. It is to be understood that the various embodiments shown in the figures are merely illustrative representations and are not necessarily drawn to scale. 
     Several details describing structures or processes that are well-known and often associated with robotic systems and subsystems, but that can unnecessarily obscure some significant aspects of the disclosed techniques, are not set forth in the following description for purposes of clarity. Moreover, although the following disclosure sets forth several embodiments of different aspects of the present technology, several other embodiments can have different configurations or different components than those described in this section. Accordingly, the disclosed techniques can have other embodiments with additional elements or without several of the elements described below. 
     Many embodiments or aspects of the present disclosure described below can take the form of computer- or controller-executable instructions, including routines executed by a programmable computer or controller. Those skilled in the relevant art will appreciate that the disclosed techniques can be practiced on computer or controller systems other than those shown and described below. The techniques described herein can be embodied in a special-purpose computer or data processor that is specifically programmed, configured, or constructed to execute one or more of the computer-executable instructions described below. Accordingly, the terms “computer” and “controller” as generally used herein refer to any data processor and can include Internet appliances and handheld devices (including palm-top computers, wearable computers, cellular or mobile phones, multi-processor systems, processor-based or programmable consumer electronics, network computers, mini computers, and the like). Information handled by these computers and controllers can be presented at any suitable display medium, including a liquid crystal display (LCD). Instructions for executing computer- or controller-executable tasks can be stored in or on any suitable computer-readable medium, including hardware, firmware, or a combination of hardware and firmware. Instructions can be contained in any suitable memory device, including, for example, a flash drive, USB device, and/or other suitable medium. 
     The terms “coupled” and “connected,” along with their derivatives, can be used herein to describe structural relationships between components. It should be understood that these terms are not intended as synonyms for each other. Rather, in particular embodiments, “connected” can be used to indicate that two or more elements are in direct contact with each other. Unless otherwise made apparent in the context, the term “coupled” can be used to indicate that two or more elements are in either direct or indirect (with other intervening elements between them) contact with each other, or that the two or more elements co-operate or interact with each other (e.g., as in a cause-and-effect relationship, such as for signal transmission/reception or for function calls), or both. 
     Suitable Environments 
       FIG.  1    is an illustration of an example environment in which a robotic system  100  with a coordinated transfer mechanism may operate. The robotic system  100  can include and/or communicate with one or more units (e.g., robots) configured to execute one or more tasks. Aspects of the coordinated transfer mechanism can be practiced or implemented by the various units. 
     For the example illustrated in  FIG.  1   , the robotic system  100  can include an unloading unit  102 , a transfer unit  104  (e.g., a palletizing robot and/or a piece-picking robot), a transport unit  106 , a loading unit  108 , or a combination thereof in a warehouse or a distribution/shipping hub. Each of the units in the robotic system  100  can be configured to execute one or more tasks. The tasks can be combined in sequence to perform an operation that achieves a goal, such as to unload objects from a truck or a van and store them in a warehouse or to unload objects from storage locations and prepare them for shipping. In some embodiments, the task can include placing the objects on a target location (e.g., on top of a pallet and/or inside a bin/cage/box/case). As described in detail below, the robotic system  100  can derive plans (e.g., placement locations/orientations, sequence for transferring the objects, and/or corresponding motion plans) for placing and/or stacking the objects. Each of the units can be configured to execute a sequence of actions (e.g., operating one or more components therein) according to one or more of the derived plans to execute a task. 
     In some embodiments, the task can include manipulation (e.g., moving and/or reorienting) of a target object  112  (e.g., one of the packages, boxes, cases, cages, pallets, etc. corresponding to the executing task) from a start/source location  114  to a task/destination location  116 . For example, the unloading unit  102  (e.g., a devanning robot) can be configured to transfer the target object  112  from a location in a carrier (e.g., a truck) to a location on a conveyor. Also, the transfer unit  104  can be configured to transfer the target object  112  from one location (e.g., the conveyor, a pallet, or a bin) to another location (e.g., a pallet, a bin, etc.). For another example, the transfer unit  104  (e.g., a palletizing robot) can be configured to transfer the target object  112  from a source location (e.g., a pallet, a pickup area, and/or a conveyor) to a destination pallet. In completing the operation, the transport unit  106  (e.g., a conveyor, an automated guided vehicle (AGV), a shelf-transport robot, etc.) can transfer the target object  112  from an area associated with the transfer unit  104  to an area associated with the loading unit  108 , and the loading unit  108  can transfer the target object  112  (by, e.g., moving the pallet carrying the target object  112 ) from the transfer unit  104  to a storage location (e.g., a location on the shelves). Details regarding the task and the associated actions are described below. 
     For illustrative purposes, the robotic system  100  is described in the context of a packaging and/or shipping center; however, it is understood that the robotic system  100  can be configured to execute tasks in other environments/for other purposes, such as for manufacturing, assembly, storage/stocking, healthcare, and/or other types of automation. It is also understood that the robotic system  100  can include other units, such as manipulators, service robots, modular robots, etc., not shown in  FIG.  1   . For example, in some embodiments, the robotic system  100  can include a depalletizing unit for transferring the objects from cage carts or pallets onto conveyors or other pallets, a container-switching unit for transferring the objects from one container to another, a packaging unit for wrapping/casing the objects, a sorting unit for grouping objects according to one or more characteristics thereof, a piece-picking unit for manipulating (e.g., for sorting, grouping, and/or transferring) the objects differently according to one or more characteristics thereof, or a combination thereof. 
     The robotic system  100  can include physical or structural members (e.g., robotic manipulator arms) that are connected at joints for motion (e.g., rotational and/or translational displacements). The structural members and the joints can form a kinetic chain configured to manipulate an end-effector (e.g., a gripper) configured to execute one or more tasks (e.g., gripping, spinning, welding, etc.) depending on the use/operation of the robotic system  100 . The robotic system  100  can include actuation devices (e.g., motors, actuators, wires, artificial muscles, electroactive polymers, etc.) configured to drive or manipulate (e.g., displace and/or reorient) the structural members about or at a corresponding joint. In some embodiments, the robotic system  100  can include transport motors configured to transport the corresponding units/chassis from place to place. 
     The robotic system  100  can include sensors configured to obtain information used to implement the tasks, such as for manipulating the structural members and/or for transporting the robotic units. The sensors can include devices configured to detect or measure one or more physical properties of the robotic system  100  (e.g., a state, a condition, and/or a location of one or more structural members/joints thereof) and/or of a surrounding environment. Some examples of the sensors can include accelerometers, gyroscopes, force sensors, strain gauges, tactile sensors, torque sensors, position encoders, etc. 
     In some embodiments, for example, the sensors can include one or more imaging devices (e.g., visual and/or infrared cameras, 2D and/or 3D imaging cameras, distance measuring devices such as lidars or radars, etc.) configured to detect the surrounding environment. The imaging devices can generate representations of the detected environment, such as digital images and/or point clouds, that may be processed via machine/computer vision (e.g., for automatic inspection, robot guidance, or other robotic applications). As described in further detail below, the robotic system  100  can process digital images and/or point clouds to identify the target object  112 , the start location  114 , the task location  116 , a pose of the target object  112 , a confidence measure regarding the start location  114  and/or the pose, or a combination thereof. 
     For manipulating the target object  112 , the robotic system  100  can capture and analyze an image of a designated area (e.g., a pickup location, such as inside of a bin or on a pallet) to identify the target object  112  and the start location  114  thereof. Similarly, the robotic system  100  can capture and analyze an image of another designated area (e.g., a drop location for placing objects on the conveyor, a location for placing objects inside the container, or a location on the pallet for stacking purposes) to identify the task location  116 . For example, the imaging devices can include one or more cameras configured to generate images of the pickup area and/or one or more cameras configured to generate images of the task area (e.g., drop area). Based on the captured images, as described below, the robotic system  100  can determine the start location  114 , the task location  116 , the associated poses, a packing/placement plan, a transfer/packing sequence, and/or other processing results. 
     In some embodiments, for example, the sensors can include position sensors (e.g., position encoders, potentiometers, etc.) configured to detect positions of structural members (e.g., the robotic arms and/or the end-effectors) and/or corresponding joints of the robotic system  100 . The robotic system  100  can use the position sensors to track locations and/or orientations of the structural members and/or the joints during execution of the task. 
     Suitable System 
       FIG.  2    is a block diagram illustrating the robotic system  100  in accordance with one or more embodiments of the present technology. In some embodiments, for example, the robotic system  100  (e.g., at one or more of the units and/or robots described above) can include electronic/electrical devices, such as one or more processors  202 , one or more storage devices  204 , one or more communication devices  206 , one or more input-output devices  208 , one or more actuation devices  212 , one or more transport motors  214 , one or more sensors  216 , or a combination thereof. The various devices can be coupled to each other via wire connections and/or wireless connections. For example, the robotic system  100  can include a bus, such as a system bus, a Peripheral Component Interconnect (PCI) bus or PCI-Express bus, a HyperTransport or industry standard architecture (ISA) bus, a small computer system interface (SCSI) bus, a universal serial bus (USB), an IIC (I2C) bus, or an Institute of Electrical and Electronics Engineers (IEEE) standard 1394 bus (also referred to as “Firewire”). Also, for example, the robotic system  100  can include bridges, adapters, processors, or other signal-related devices for providing the wire connections between the devices. The wireless connections can be based on, for example, cellular communication protocols (e.g., 3G, 4G, LTE, 5G, etc.), wireless local area network (LAN) protocols (e.g., wireless fidelity (Wi-Fi)), peer-to-peer or device-to-device communication protocols (e.g., Bluetooth, Near-Field communication (NFC), etc.), Internet of Things (IoT) protocols (e.g., NB-IoT, LTE-M, etc.), and/or other wireless communication protocols. 
     The processors  202  can include data processors (e.g., central processing units (CPUs), special-purpose computers, and/or onboard servers) configured to execute instructions (e.g., software instructions) stored on the storage devices  204  (e.g., computer memory). In some embodiments, the processors  202  can be included in a separate/stand-alone controller that is operably coupled to the other electronic/electrical devices illustrated in  FIG.  2    and/or the robotic units illustrated in  FIG.  1   . The processors  202  can implement the program instructions to control/interface with other devices, thereby causing the robotic system  100  to execute actions, tasks, and/or operations. 
     The storage devices  204  can include non-transitory computer-readable mediums having stored thereon program instructions (e.g., software). Some examples of the storage devices  204  can include volatile memory (e.g., cache and/or random-access memory (RAM)) and/or non-volatile memory (e.g., flash memory and/or magnetic disk drives). Other examples of the storage devices  204  can include portable memory and/or cloud storage devices. 
     In some embodiments, the storage devices  204  can be used to further store and provide access to processing results and/or predetermined data/thresholds. For example, the storage devices  204  can store master data  252  that includes descriptions of objects (e.g., boxes, cases, and/or products) that may be manipulated by the robotic system  100 . In one or more embodiments, the master data  252  can include a dimension, a shape (e.g., templates for potential poses and/or computer-generated models for recognizing the object in different poses), a color scheme, an image, identification information (e.g., bar codes, quick response (QR) codes, logos, etc., and/or expected locations thereof), an expected weight, other physical/visual characteristics, or a combination thereof for the objects expected to be manipulated by the robotic system  100 . In some embodiments, the master data  252  can include manipulation-related information regarding the objects, such as a center-of-mass (CoM) location on each of the objects, expected sensor measurements (e.g., for force, torque, pressure, and/or contact measurements) corresponding to one or more actions/maneuvers, or a combination thereof. 
     The communication devices  206  can include circuits configured to communicate with external or remote devices via a network. For example, the communication devices  206  can include receivers, transmitters, modulators/demodulators (modems), signal detectors, signal encoders/decoders, connector ports, network cards, etc. The communication devices  206  can be configured to send, receive, and/or process signals according to one or more communication protocols (e.g., the Internet Protocol (IP), wireless communication protocols, etc.). In some embodiments, the robotic system  100  can use the communication devices  206  to exchange information between units of the robotic system  100  and/or exchange information (e.g., for reporting, data gathering, analyzing, and/or troubleshooting purposes) with systems or devices external to the robotic system  100 . 
     The input-output devices  208  can include user interface devices configured to communicate information to and/or receive information from human operators. For example, the input-output devices  208  can include a display  210  and/or other output devices (e.g., a speaker, a haptics circuit, or a tactile feedback device, etc.) for communicating information to the human operator. Also, the input-output devices  208  can include control or receiving devices, such as a keyboard, a mouse, a touchscreen, a microphone, a user interface (UI) sensor (e.g., a camera for receiving motion commands), a wearable input device, etc. In some embodiments, the robotic system  100  can use the input-output devices  208  to interact with the human operators in executing an action, a task, an operation, or a combination thereof. 
     The robotic system  100  can include physical or structural members (e.g., robotic manipulator arms) that are connected at joints for motion (e.g., rotational and/or translational displacements). The structural members and the joints can form a kinetic chain configured to manipulate an end-effector (e.g., the gripper) configured to execute one or more tasks (e.g., gripping, spinning, welding, etc.) depending on the use/operation of the robotic system  100 . The robotic system  100  can include the actuation devices  212  (e.g., motors, actuators, wires, artificial muscles, electroactive polymers, etc.) configured to drive or manipulate (e.g., displace and/or reorient) the structural members about or at a corresponding joint. In some embodiments, the robotic system  100  can include the transport motors  214  configured to transport the corresponding units/chassis from place to place. 
     The robotic system  100  can include the sensors  216  configured to obtain information used to implement the tasks, such as for manipulating the structural members and/or for transporting the robotic units. The sensors  216  can include devices configured to detect or measure one or more physical properties of the robotic system  100  (e.g., a state, a condition, and/or a location of one or more structural members/joints thereof) and/or of a surrounding environment. Some examples of the sensors  216  can include accelerometers, gyroscopes, force sensors, strain gauges, tactile sensors, torque sensors, position encoders, etc. 
     In some embodiments, for example, the sensors  216  can include one or more imaging devices  222  (e.g., visual and/or infrared cameras, 2D and/or 3D imaging cameras, distance measuring devices such as lidars or radars, etc.) configured to detect the surrounding environment. The imaging devices  222  can generate representations of the detected environment, such as digital images and/or point clouds, that may be processed via machine/computer vision (e.g., for automatic inspection, robot guidance, or other robotic applications). As described in further detail below, the robotic system  100  (via, e.g., the processors  202 ) can process the digital image and/or the point cloud to identify the target object  112  of  FIG.  1   , the start location  114  of  FIG.  1   , the task location  116  of  FIG.  1   , a pose of the target object  112 , a confidence measure regarding the start location  114  and/or the pose, or a combination thereof. 
     For manipulating the target object  112 , the robotic system  100  (via, e.g., the various circuits/devices described above) can capture and analyze image data of a designated area (e.g., a pickup location, such as inside the truck or on the conveyor belt) to identify the target object  112  and the start location  114  thereof. Similarly, the robotic system  100  can capture and analyze image data of another designated area (e.g., a drop location for placing objects on the conveyor, a location for placing objects inside the container, or a location on the pallet for stacking purposes) to identify the task location  116 . For example, the imaging devices  222  can include one or more cameras configured to generate image data of the pickup area and/or one or more cameras configured to generate image data of the task area (e.g., drop area). Based on the image data, as described below, the robotic system  100  can determine the start location  114 , the task location  116 , the associated pose, the packing/placement location, the motion plan, and/or other processing results. 
     In some embodiments, for example, the sensors  216  can include position sensors  224  (e.g., position encoders, potentiometers, etc.) configured to detect positions of structural members (e.g., the robotic arms and/or the end-effectors) and/or corresponding joints of the robotic system  100 . The robotic system  100  can use the position sensors  224  to track locations and/or orientations of the structural members and/or the joints during execution of the task. 
     First Example Transfer Environment 
       FIG.  3    is a top view illustrating a first example transfer environment in accordance with one or more embodiments of the present technology. The transfer environment (e.g., a portion of the environment shown in  FIG.  1   ) can include a picking robot  302  (e.g., an instance of the transfer unit  104  of  FIG.  1   ), a source sensor  306 , and/or a destination sensor  308 . The source sensor  306  can include an instance of the sensors  216  of  FIG.  2    (e.g., a two-dimensional (2D) camera, a three-dimensional (3D) camera, and/or a depth sensor) configured to sense/depict the start location  114  of  FIG.  1   . Similarly, the destination sensor  308  can include an instance of the sensors  216  (e.g., a 2D camera, a 3D camera, and/or a depth sensor) configured to sense/depict the task location  116  of  FIG.  1   . 
     The robotic system  100  can operate (via, e.g., the processor(s)  202  of  FIG.  2   ) the picking robot  302  to pick the target object  112  from a source container  304  (e.g., a pallet, a bin, a cart, a box, a case, etc.), transfer the target object  112  across space, and place the target object  112  at a destination container  310  (e.g., a pallet, a bin, a cart, a box, a case, etc.). For example, the robotic system  100  can derive and/or obtain a motion plan (e.g., a sequence of commands and/or settings for the actuation devices  212  of  FIG.  2    and/or the transport motor  214  of  FIG.  2   ) configured to operate the picking robot  302  and manipulate/transfer the target object  112  along a corresponding path. The robotic system  100  can implement the motion plan, such as by communicating the sequence of commands and/or settings to the picking robot  302  and/or by executing the sequence of commands and/or settings via the picking robot  302 . In executing the motion plan, the picking robot  302  can place an end-effector (e.g., a gripper) thereof at a designated location about the target object  112 , engage/contact the target object  112  with the end-effector, and grip the target object  112  with the end-effector. Once gripped, the picking robot  302  can lift the target object  112  and/or transfer the target object  112  laterally (e.g., from the source container  304  toward the destination container  310 ). The picking robot  302  can lower the target object  112  on a designated location in the destination container  310  and release the target object  112  to complete a transfer task for the target object  112  according to the motion plan. 
     The source sensor  306  and/or the destination sensor  308  can be used to determine real-time information regarding the source container  304 , destination container  310 , and/or contents (e.g., object) therein. For example, the source sensor  306  and/or the destination sensor  308  can generate real-time image data (e.g., 2D/3D images, depth maps, point clouds, etc.) of the start location  114  and/or the task location  116 . The robotic system  100  can process the image data to determine locations and/or edges of objects and/or identify objects. Accordingly, in some embodiments, the robotic system  100  can use the image data to derive/generate the motion plan, such as by identifying the target object, deriving approach location/path to grip the target object, and/or deriving approach location/path to place the target object  112 . In some embodiments, the robotic system  100  can use the image data to track a progress during execution of the motion plan. For example, the robotic system  100  can process the image data to locate the end-effector and/or the target object  112 , detect collisions, detect object loss (e.g., losing grip and dropping the target object  112  during transfer), and/or other events/physical attributes. 
     For illustrative purposes, the source container  304  and the destination container  310  are described as open-top containers having at least a pair of opposing vertical walls. However, it is understood that the source container  304  and the destination container  310  can include various other structures as described above. For example, the source container  304  and/or the destination container  310  can include a pallet that doesn&#39;t have any vertical walls extending above a placement surface. Also, the source container  304  and/or the destination container  310  can include an open-top box having three or more vertical walls. Further, the source container  304  and/or the destination container  310  can be implemented via a car track, a conveyor, a cart, and/or other transport container. 
     First Example Transfer States 
       FIGS.  4 A- 4 D  are top views illustrating a processing sequence for the first example transfer environment in accordance with one or more embodiments of the present technology.  FIGS.  4 A- 4 D  illustrate various states of the picking robot and/or the target object during the processing sequence. As illustrated in  FIG.  4 A , the robotic system  100  can control the source sensor  306  to generate/obtain an image data depicting the source container  304  and object(s) therein. Based on the image data, the robotic system  100  can process the image data to identify the target object  112  and derive a motion plan to pick up, transfer and/or place the target object  112 . According to the motion plan, the robotic system  100  can place the end-effector (by, e.g., operating the picking robot  302  to laterally/vertically displace the end-effector) about or over the target object  112  and pick (by, e.g., gripping with the end-effector and/or lifting) the target object  112 . 
     As illustrated in  FIG.  4 B , the robotic system  100  can control the picking robot  302  to transfer the target object  112  across space (e.g., laterally and/or vertically) and move toward the destination container  310  according to the motion plan. Once the target object  112  is within a threshold distance from and/or over a derived location (e.g., a placement location), the picking robot  302  can place (by, e.g., lowering and/or releasing from the end-effector) the target object  112 . In some embodiments, the robotic system  100  can operate (according to, e.g., a portion of the motion plan, such as a source reloading portion) one or more other units (e.g., an AGV, a shelf-transport robot, etc.) to replace the initial source container  304  with a new source container at the start location  114  while the picking robot  302  transfers and/or places the target object  112 . In other embodiments, the source container  304  can include multiple objects which can be selected as the new target object  402 . 
     As illustrated in  FIG.  4 C , the robotic system  100  can control the source sensor  306  to generate a new image data. The robotic system  100  can generate the image data similarly as described above to depict the source container  304 . Accordingly, the robotic system  100  can process the new image data and derive a new motion plan as described above. The robotic system  100  can operate the picking robot  302  to pick a new target object  402  in the source container  304  at the start location  114 . 
     As illustrated in  FIG.  4 D , the robotic system  100  can control the picking robot  302  to transfer the new target object  402  across space and move toward the destination container  310  according to the new motion plan. The robotic system  100  can place the new target object  402  at a designated location, which can be adjacent to and/or over the previously placed/targeted object  112 . The above-described example states can be repeated according to the processing sequence to pack the destination container  310  (e.g., a shipping container or a box) with targeted objects, such as for fulfilling a shipping order. 
     Second Example Transfer Environment 
       FIG.  5 A  is a top view illustrating a second example transfer environment, and  FIG.  5 B  is a profile view illustrating the second example transfer environment, both in accordance with one or more embodiments of the present technology. Referring to  FIGS.  5 A and  5 B  together, the transfer environment (e.g., a portion of the environment shown in  FIG.  1   ) can include a picking robot  302  (e.g., an instance of the transfer unit  104  of  FIG.  1   ), a source sensor  306 , a destination sensor  308 , a source container  304 , and/or a destination container  310  similarly as the environment illustrated in  FIG.  3   . 
     The environment can further include a transfer tray  506  configured to laterally transfer the target object  112 . The transfer tray  506  can be operably coupled to a lateral transfer mechanism. The lateral transfer mechanism can include a guiding rail  504  and be configured to move the transfer tray  506  laterally between the source container  304  and the destination container  310 . In some embodiments, the transfer tray  506  can move along a horizontal line/plane via the guiding rail  504  and one or more transport motors (not shown). The horizontal line/plane of movement for the transfer tray  506  can be located vertically above the source container  304  and the destination container  310 , below the source/destination sensors  306  and  308 , and/or below a top movement range of the picking robot  302 . In some embodiments, the transfer tray  506  may include one or more sensor devices (not shown). The sensor devices can be integrated or attached to the transfer tray  506  to provide object information about the target object  112  currently on the transfer tray  506 . For example, the sensor devices can be object identifier scanners, such as a radio-frequency identification (RFID) scanner to read RFID tags of the target object  112 , or sensors capable of determining physical properties of the target object  112  such as weight or mass. 
     As described above, the robotic system  100  of  FIG.  1    can obtain and process image data to analyze real-time conditions of the source container  304  and/or the destination container  310 . Further, the robotic system  100  can process the image data to identify the target object  112  and to derive a motion plan for transferring the target object  112  from the source container  304  to a derived location in/on the destination container  310 . Moreover, the robotic system  100  can implement and/or execute the motion plan as described above. 
     In executing the motion plan, the robotic system  100  can control the picking robot  302  to pick the target object  112 . The robotic system  100  can derive the motion plan to move the transfer tray  506  toward the source container  304  and/or below the target object  112  once the target object  112  is lifted above a predetermined height. In some embodiments, the timing for moving the transfer tray  506  can be based on additional image data from the source sensor  306  and/or a tracked height of the end-effector. 
     In some embodiments, the robotic system  100  can move the transfer tray  506  and/or operate the picking robot  302  according to outputs from one or more area sensors  502 . The robotic system  100  can include the area sensors  502  that are configured to detect crossing events. Some examples of the area sensors  502  can include transmitters that transmit signals (e.g., optical signals, infrared signals, laser, etc.) along a crossing threshold  512 . The transmitters can further include signal detectors that detect the transmitted signals. The area sensors  502  can determine that an object entered/crossed the crossing threshold  512  based on detecting a disruption (e.g., discontinuity) in receiving the transmitted signal. Further, the area sensors  502  can determine that the object exited/cleared the crossing threshold  512  based on detecting the transmitted signals after the disruption. Accordingly, the robotic system  100  can include the area sensors  502  configured with the crossing threshold  512  above and/or coincident with an upper portion (e.g., a top surface) of the transfer tray  506 . Thus, when the end-effector and/or the target object  112  crosses the crossing threshold  512  and then subsequently exits the crossing threshold  512  during the picking operation, the area sensors  502  can generate an exit event. The robotic system  100  can use the exit event as a trigger to laterally move the transfer tray  506  until it is within a threshold distance from, under, and/or overlapping the target object  112 . 
     Once the transfer tray  506  is in position relative to the target object  112  (e.g., under the target object  112  and/or at a predetermined stop location), the robotic system  100  can place the target object  112  on the transfer tray  506 . For example, the robotic system  100  can operate the picking robot  302  to lower the target object  112  and/or release the target object  112  onto the transfer tray  506 . In some embodiments, the robotic system  100  can include the area sensors  502  configured with the crossing threshold  512  just above vertical edges/walls of the source container  304  and/or the upper surface of the transfer tray  506 , thereby reducing a vertical distance between the target object and the transfer tray  506 . 
     The robotic system  100  can operate the transfer tray  506  to displace the target object  112  along lateral (e.g., horizontal) directions. Accordingly, the picking robot  302  can be used primarily for vertically displacing or lifting the target object  112 . Using the transfer tray  506  to laterally displace the target object  112 , thereby reducing horizontal movement of the target object  112  via the picking robot  302 , increases throughput for the robotic system  100 . Using the picking robot  302  to primarily lift the target object  112  reduces total grip time, horizontal forces, and/or collisions that contribute to piece loss (e.g., due to failed grip). Accordingly, the robotic system  100  can reduce the piece loss rate. Further, even if grip fails, the target object  112  would drop into the source container  304  according to the above-described configuration. Thus, even dropped pieces can be manipulated again (via, e.g., re-imaging the source container  304  and re-deriving motion plans) without assistance from human operators. Moreover, since the target object  112  is no longer gripped during lateral transfer, horizontal transfer speed can be increased using the transfer tray  506  in comparison to horizontally transferring the target object  112  via the picking robot  302 . Thus, the robotic system  100  can reduce the time necessary to transfer each object using the transfer tray  506 . 
     For placing the target object  112  at/in the destination container  310 , the robotic system  100  can include a stopper  508  configured to horizontally displace the target object  112  from the top surface of the transfer tray  506 . In some embodiments, the stopper  508  can be located over the destination container  310  at a height that is above the transfer tray  506 . The stopper  508  can be configured to move horizontally, such as along the guiding rail  504  and/or via another mechanism. To place/drop the target object  112 , the robotic system  100  can move the stopper  508  along a lateral direction until an edge/surface of the stopper  508  is directly above a drop location  510 . Once the target object  112  is placed on the transfer tray  506 , the robotic system  100  can move the transfer tray  506  toward and past the drop location  510 . With the stopper  508  (e.g., a bottom portion thereof) vertically located just above the top surface of the transfer tray  506 , the target object  112  can be held in place by the stopper  508  while the transfer tray  506  continues moving past the stopper  508 . Accordingly, the target object  112  can slide off the transfer tray  506  and drop into the destination container  310 . Thus, the robotic system  100  can provide increased success rate for the tasks, allow for simpler/smaller gripper designs, and reduce probability of double pick events. 
     Second Example Transfer States 
       FIGS.  6 A- 6 D  are top views illustrating a processing sequence for the second example transfer environment in accordance with one or more embodiments of the present technology.  FIGS.  6 A- 6 D  illustrate various states of the robotic system  100  of  FIG.  1    and/or the target object  112  during the processing sequence. As illustrated in  FIG.  6 A , the robotic system  100  can control the source sensor  306  to generate an image data depicting the source container  304  and object(s) therein. Based on the image data, the robotic system  100  can process the image data to identify the target object  112  and derive a motion plan to pick up, transfer and/or place the target object  112 . According to the motion plan, the robotic system  100  can operate the picking robot  302  to pick the target object  112  (by, e.g., gripping with the end-effector and/or lifting). Once the target object  112  reaches a predetermined height (e.g., as represented by a triggering event from the area sensors  502 ), the robotic system  100  can move the transfer tray  506  from a previous location (e.g., over and/or within a predetermined distance from the destination container  310 ) to over and/or within a predetermined distance from the source container  304 . 
     As illustrated in  FIG.  6 B , the robotic system  100  can control the picking robot  302  to drop and/or place the target object  112  onto the transfer tray  506  below. In some embodiments, the robotic system  100  can adjust a position of the stopper  508  according to a derived drop location  510  for the target object  112 . In other embodiments, the stopper  508  can be located at a fixed/static location. The robotic system  100  can move the transfer tray  506  and the target object  112  thereon toward the destination container  310 . In some embodiments, the robotic system  100  can replace or refill the source container  304  at the start location  114  after placing the transfer tray  506  below the target object  112  and/or while the transfer tray  506  moves toward the destination container  310 . In other embodiments, the source container  304  can include multiple objects which can be selected as the new target object  402 . 
     As illustrated in  FIG.  6 C , the robotic system  100  can move the transfer tray  506  past the stopper  508 . Accordingly, the target object  112  can be stopped (e.g., not moving laterally) based on contacting the stopper  508  while the transfer tray  506  continues to move laterally. During the lateral transfer, the robotic system  100  can generate additional image data for the source container  304 , generate the corresponding motion plan, and/or pick the next object  402  from the source container  304 . 
     As illustrated in  FIG.  6 D , the robotic system  100  can continue moving the transfer tray  506  past the stopper  508 . As a result, the target object  112  can slide off the transfer tray  506  and drop into the destination container  310 . Once the transfer tray  506  reaches a predetermined location (such as for moving a trailing edge of the transfer tray  506  up to or past the stopper  508 ) and/or once the target object  112  slides off the transfer tray  506 , the robotic system  100  can move the transfer tray  506  toward the source container  304 . The robotic system  100  can repeat the above described states to pack multiple objects into the destination container  310 . 
       FIG.  6 E  is a flow diagram of a first example method  600  for operating the robotic system  100  of  FIG.  1    in accordance with one or more embodiments of the present disclosure. The example flow diagram can represent processes and/or maneuvers executed by one or more units in the second example transfer environment. Accordingly, the example flow diagram, or a portion thereof, can correspond to a motion plan for executing a task to transfer the target object from the source container to the destination container. 
     At block  602 , the robotic system  100  can obtain via the source sensor image data depicting the source container  304  of  FIG.  5 A  and contents therein (e.g., the target object  112  of  FIG.  5 A ). For example, the robotic system  100  can generate 2D/3D images of the start location  114  of  FIG.  1    using the source sensor  306  of  FIG.  5 A . The image data may be received by the one or more processors  202  of  FIG.  2   . Accordingly, the robotic system  100  can obtain and process the image data that represents the target object  112  located at the start location  114  (e.g., in the source container  304 ). 
     At block  604 , the robotic system  100  can analyze the image data to identify the target object  112 , an object location, and/or an object pose, such as based on identifying and processing edges within the image data. The robotic system  100  can analyze the edges to detect and identify an object. For example, the robotic system  100  can determine an area bounded by a set of intersecting edges as a surface of an object. The robotic system  100  can also compare one or more portions of an image to images in the master data  252  that represent surfaces of known/registered objects. The robotic system  100  can detect an object (by, e.g., determining that a single or a particular object exists or is at a particular location) when an image of the area and/or dimensions of the area match information in the master data  252 . In some embodiments, the robotic system  100  can process a 3D image and identify a surface according to exposed edges and/or exposed corners. 
     At block  606 , the robotic system  100  can use such processing results to derive a motion plan. For example, the robotic system  100  can determine a pickup location, a transfer path for the target object, corresponding maneuvers of the picking robot, and/or associated commands/settings. The robotic system  100  can determine a real-world location for the detected object according to a predetermined process or equation that maps imaged locations to real-world locations. The robotic system  100  can derive the motion plan based on identifying the task location  116  of  FIG.  1    (e.g., the destination container  310  or a location therein) and deriving a travel path for the target object  112  between the current real-world location and the task location  116 . The robotic system  100  can derive the travel path based on a predetermined set of rules, processes, routines. The robotic system  100  can derive the motion plan based on translating the travel path to a set/sequence of commands/settings and/or conditions for executing such commands/settings for the picking robot  302  of  FIG.  5 A . 
     As an illustrative example, the robotic system  100  can derive the motion plan for operating the picking robot  302  and the end-effector thereof to place the end-effector directly adjacent to (e.g., directly above) and contact the target object, grip the target object  112  with the end-effector, and lift the target object  112  to the predetermined height. In some embodiments, the robotic system  100  can derive the motion plan to lift the target object  112  until the exit event is detected by the area sensors  502  as described above. The robotic system  100  can further derive the motion plan to operate the picking robot  302  and/or the transfer tray  506  of  FIG.  5 A  to place the target object  112  on the transfer tray  506  and laterally transfer the target object  112  via the transfer tray  506 . For example, the robotic system  100  can derive the motion plan to place the transfer tray  506  within a threshold distance from and/or under the target object  112  based on the target object  112  reaching the predetermined height (e.g., based on detecting the exit event). The robotic system  100  can also derive the motion plan to operate the transfer tray  506  and/or the stopper  508  of  FIG.  5 A  to drop the target object  112  at the task location  116 . 
     The robotic system  100  can implement the motion plan, such as by communicating the motion plan and/or the associated commands/settings from the processors  202  to the picking robot  302  and/or a system for moving the transfer tray  506  and/or the stopper  508 . The robotic system  100  can further implement the motion plan by executing the motion plan via the picking robot  302 , the transfer tray  506 , and/or the stopper  508 . Accordingly, at block  608 , the robotic system  100  can implement a portion (e.g., a picking portion) of the motion plan and pick (e.g., grip and/or lift) the target object via the picking robot  302 . As an initial state, in some embodiments, the transfer tray can be over or within a predetermined distance from the destination container  310 . 
     At block  610 , the robotic system  100  can determine a clearing event. The robotic system  100  can determine the clearing event that represents the target object  112  reaching the predetermined height. In some embodiments, the robotic system  100  can determine the clearing event based on tracking a height of the end-effector while implementing the motion plan, such as when the tracked height reaches a height greater than a minimum clearance height plus a known height of the target object  112 . The robotic system  100  can also determine the clearing event based on detecting an exit event with the area sensors  502  as described above. 
     At block  612 , the robotic system  100  can implement a portion (e.g., a source transfer portion) of the motion plan using the clearing event as a trigger to move the transfer tray  506  toward the source container  304 . Accordingly, for example, the robotic system  100  can place the transfer tray  506  directly under the picked target object  112 . At block  614 , the robotic system  100  can implement a portion (e.g., a tray placement portion) of the motion plan to place/drop the target object  112  on the transfer tray  506 , such as by lowering the target object  112  and/or releasing the target object  112  from the end-effector. 
     In some embodiments, as illustrated at block  616 , the robotic system  100  can implement a portion (e.g., a stopper placement portion and/or a stopper alignment portion) of the motion plan to position the stopper  508 , such as by moving the stopper  508  along a horizontal direction/plane and aligning an edge of the stopper over a drop location. At block  618 , the robotic system  100  can implement a portion (e.g., a destination transfer portion) of the motion plan to move the transfer tray  506  toward, past, and/or over the destination container  310  and at least partially past the stopper  508  as described above. Accordingly, the robotic system  100  can operate the components to slide the target object  112  off the transfer tray  506  and drop it into the destination container  310 . In some embodiments, as illustrated at block  620 , the robotic system  100  can implement a portion of the motion plan to replace the source container  304  and/or reload a new object (e.g., the new target object  402  of  FIG.  6 C ) at the start location  114  for the next task. In other embodiments, the source container  304  can include multiple objects which can be selected as the new target object  402 . The operational flow can pass to block  602  and the robotic system  100  can repeat the above-described process to execute the next task for the new object. 
     Third Example Transfer Environment 
       FIG.  7 A  is a top view illustrating a third example transfer environment, and  FIG.  7 B  is a profile view illustrating the third example transfer environment, both in accordance with one or more embodiments of the present technology. Referring to  FIGS.  7 A and  7 B  together, the transfer environment (e.g., a portion of the environment shown in  FIG.  1   ) can be similar to the environment illustrated in  FIGS.  5 A and  5 B . For example, the third example transfer environment can include a picking robot  302  (e.g., an instance of the transfer unit  104  of  FIG.  1   ), a source sensor  306 , a destination sensor  308 , a source container  304 , a destination container  310 , a transfer tray  506 , a guiding rail  504 , a stopper  508 , and/or an area sensor  502  as described above. 
     For the third example transfer environment, the stopper  508  can be located closer to the source container  304  in comparison to the second example transfer environment. Further, the stopper  508  can be configured to have at least an engaged state for contacting the target object  112  and a disengaged state for allowing the target object  112  to pass by. For example, the robotic system  100  can move the stopper  508  along a vertical direction in  FIG.  7 A  and/or up/down as shown in  FIG.  7 B  for the engaged and disengaged states. Accordingly, the robotic system  100  can operate the transfer tray  506  and the stopper  508  such that the stopper  508  contacts/engages the target object  112  on the transfer tray  506  when the tray  506  is moving toward the source container  304 . In other words, the robotic system  100  can operate the stopper  508  to be in the disengaged state after the picking robot  302  places the target object  112  on the transfer tray  506 . The transfer tray  506  can move toward and/or over the destination container  310  with the stopper  508  in the disengaged state, thereby continuing to carry the target object  112  thereon. Once the transfer tray  506  reaches a predetermined location about the destination container  310 , the robotic system  100  can operate the stopper  508  to be in the engaged state. The robotic system  100  can subsequently move the transfer tray  506  toward the source container  304  and past the stopper  508 . With the stopper  508  in the engaged state, the stopper  508  can contact the target object  112  such that the target object  112  slides off the transfer tray  506  and drops into the destination container  310 . Accordingly, with the stopper  508  located closer to the source container  304  and having engaged/disengaged states, the robotic system  100  can further increase the throughput by reducing the total amount of distance traveled by the transfer tray  506  for each task. Thus, the execution time of each task can be reduced, which leads to the increased throughput. The reduction in distance traveled by the transfer tray  506  can further reduce a horizontal footprint of the robotic system  100 . Additionally, the above-described configuration can increase the success rate for completing the tasks, allow for simpler and smaller gripper designs, and reduce probability of double pick events. 
     Third Example Transfer States 
       FIGS.  8 A- 8 D  are top views illustrating a processing sequence for the third example transfer environment in accordance with one or more embodiments of the present technology.  FIGS.  8 A- 8 D  illustrate various states of the robotic system  100  of  FIG.  1    and/or the target object  112  during the processing sequence. As illustrated in  FIG.  8 A , the robotic system  100  can control the source sensor  306  to generate an image data depicting the source container  304  and object(s) therein. Based on the image data, the robotic system  100  can process the image data to identify the target object  112  and derive a motion plan or a portion thereof to pick up, transfer and/or place the target object  112 . According to the motion plan, the robotic system  100  can operate the picking robot  302  to pick the target object  112  (by, e.g., gripping with the end-effector and/or lifting). Once the target object  112  reaches a minimum height (e.g., as represented by a triggering event from the area sensors  502 ), the robotic system  100  can move the transfer tray  506  between the destination container  310  and the source container  304 . For example, the robotic system  100  can move the transfer tray  506  from locations that are adjacent to and/or over the destination container  310  to locations adjacent to and/or over the source container  304 . The initial state of the stopper  508  can be the disengaged state. 
     As illustrated in  FIG.  8 B , the robotic system  100  can control the picking robot  302  to drop and/or place the target object  112  onto the transfer tray  506  below. In some embodiments, the robotic system  100  can adjust a lateral position of the stopper  508  according to a drop location  510  for the target object  112 . In other embodiments, the stopper  508  can be located at a fixed/static lateral location. The robotic system  100  can move the transfer tray  506  and the target object  112  thereon toward the destination container  310 . In some embodiments, the robotic system  100  can replace the source container  304  at the start location  114  after placing the transfer tray  506  below the target object  112  and/or while the transfer tray  506  moves toward the destination container  310 . In other embodiments, the source container  304  can include multiple objects which can be selected as the new target object  402 . 
     As illustrated in  FIG.  8 C , the robotic system  100  can move the transfer tray  506  toward and/or over the destination container  310  and past the stopper  508  that is in the disengaged state. Once the transfer tray  506  reaches a predetermined horizontal location relative to or over the destination container  310 , the robotic system  100  can operate the stopper  508  to be in the engaged state. Subsequently, the robotic system  100  can move the transfer tray  506  toward the source container  304 . Accordingly, the target object  112  can be stopped based on contacting the stopper  508  while the transfer tray  506  continues to move laterally. While the transfer tray  506  is over the destination container  310 , the robotic system  100  can generate additional image data for the source container  304 , generate the corresponding motion plan, and/or pick the next object  402  from the source container  304 . 
     As illustrated in  FIG.  8 D , the robotic system  100  can continue moving the transfer tray  506  past the stopper  508 . As a result, the target object  112  can slide off the transfer tray  506  and drop into the destination container  310 . The transfer tray  506  can continue to move until it is over the source container  304 , within a threshold distance from the picked target object  112 , and/or under the picked target object  112 . Further, the robotic system  100  can operate the stopper  508  to be in the disengaged state. Accordingly, the robotic system  100  can return to the state illustrated in  FIG.  8 B  in preparation to place the target object  112  on the transfer tray  506  and begin lateral transfer thereof. The robotic system  100  can repeat the above described states to pack multiple objects into the destination container  310 . 
       FIG.  8 E  is a flow diagram of a second example method  800  for operating the robotic system  100  of  FIG.  1    in accordance with one or more embodiments of the present disclosure. The example flow diagram can represent processes and/or maneuvers executed by one or more units in the third example transfer environment. Accordingly, the second example method  800 , or a portion thereof, can correspond to the motion plan for executing a task to transfer the target object  112  from the source container  304  to the destination container  310 . 
     The second example method  800  can be similar to the method illustrated in  FIG.  6 E . For example, the processes represented by blocks  802 ,  804 ,  806 ,  808 ,  810 ,  812 ,  814 ,  816 ,  818 , and  820  can be similar to those represented by blocks  602 ,  604 ,  606 ,  608 ,  610 ,  612 ,  614 ,  616 ,  618 , and  620 , respectively. 
     At block  802 , the robotic system  100  can obtain image data depicting the source container  304  of  FIG.  5 A  and the contents therein (e.g., the target object  112  of  FIG.  5 A ) using the source sensor  306  of  FIG.  5 A . At block  804 , the robotic system  100  can analyze the image data to identify, detect, and locate the target object  112  based on analyzing the image data. At block  806 , the robotic system  100  can derive a motion plan based on detecting and/or locating the target object  112 . As described above, the robotic system  100  can derive the motion plan for operating the picking robot  302  of  FIG.  5 A , the transfer tray  506  of  FIG.  5 A , and/or the stopper  508  of  FIG.  5 A  to pick the target object  112 , place the target object  112  on the transfer tray  506 , and drop the target object  112  into the destination container  310 . At block  808 , the robotic system  100  can pick the target object  112  via the picking robot  302  based on the derived motion plan (e.g., by communicating the motion plan and/or the associated commands/settings from the processors  202  to the picking robot  302  and executing the motion plan via the picking robot  302 ). 
     For the second example method  800 , the robotic system  100  can implement the motion plan to operate (e.g., engage and disengage) the stopper  508  to drop the target object  112  into the destination container. For example, as illustrated at block  807 , the robotic system  100  can implement the motion plan to engage the stopper  508  (via, e.g., lowering the stopper  508  to a predetermined stopper height above a top surface of the transfer tray  506 ) after and/or during derivation of the motion plan (block  806 ). In some embodiments, the robotic system  100  can engage the stopper  508  while picking the target object  112  (block  808 ). 
     With the stopper engaged, at block  810 , the robotic system  100  can determine a clearing event by tracking a height of the end-effector while implementing the motion plan, such as when the tracked height reaches a height greater than a minimum clearance height plus a known height of the target object  112 . The robotic system  100  can also determine the clearing event by detecting an exit event using the area sensors  502 . At block  812 , using the clearing event as a trigger, the robotic system  100  can implement a portion of the motion plan to move the transfer tray  506  toward and/or over the source container  304  such that the transfer tray  506  is within a threshold distance from and/or directly under the picked target object  112 . At block  814 , the robotic system  100  can implement a portion of the motion plan to place/drop the target object  112  on the transfer tray  506 , such as by operating the picking robot  302  to lower the target object  112  and/or by releasing the target object  112  from the end-effector. In some embodiments, as illustrated at block  816 , the robotic system  100  can implement a portion of the motion plan to laterally position the stopper  508 , such as by moving the stopper  508  along a horizontal direction/plane and aligning an edge of the stopper over a drop location. Accordingly, the robotic system  100  can drop the target object  112  into the destination container  310  using the stopper  508  of  FIG.  7 A . 
     At block  817 , the robotic system  100  can disengage the stopper  508 , such as by raising the stopper  508  to a predetermined height and increasing a vertical separation from the top surface of the transfer tray  506 . The robotic system  100  can disengage the stopper  508  while or after placement of the target object  112  on the transfer tray  506  (block  814 ) and/or lateral positioning of the stopper  508  (block  816 ). The robotic system  100  can disengage the stopper  508  prior to moving the transfer tray  506  toward and/or over the destination container  310  (block  818 ). Accordingly, the transfer tray  506  can carry the target object  112  thereon over or within a threshold distance from the destination container  310 . At block  820 , in some embodiments, the robotic system  100  may implement a portion of the motion plan to replace the source container  304  and/or reload a new object (e.g., the new target object  402  of  FIG.  8 C ) at the start location  114  for the next task. In other embodiments, the source container  304  can include multiple objects which can be selected as the new target object  402 . The operational flow can pass to block  802  and the robotic system  100  can repeat the above-described process to execute the next task for the new object 
     As the above described processes repeat, such as for identifying and picking the next object  402 , the robotic system  100  can engage the stopper  508  at block  807  and move the transfer tray  506  toward and/or over the source container  304  at block  812  with the target object  112  still on the transfer tray. The target object  112  can contact the stopper  508  and begin sliding off as the transfer tray  506  continues to move toward the source container  304 , thus resulting in the target object  112  dropping into the destination container  310 . Thus, the robotic system  100  can drop the target object  112  into the destination container  310  as the transfer tray  506  moves back toward the source container  304  to receive the next object  402 . 
     Fourth Example Transfer Environment 
       FIG.  9    is a top view illustrating a fourth example transfer environment in accordance with one or more embodiments of the present technology. The transfer environment (e.g., a portion of the environment shown in  FIG.  1   ) can be similar to the environment illustrated in  FIGS.  5 A and/or  7 A . For example, the fourth example transfer environment can include a picking robot  302  (e.g., an instance of the transfer unit  104  of  FIG.  1   ), a source sensor  306 , a destination sensor  308 , a source container  304 , a destination container  310 , a transfer tray  506 , a guiding rail  504 , and/or an area sensor  502  as described above. The fourth example transfer environment can be without the stopper  508  illustrated in in  FIGS.  5 A and  7 A . For illustrative purposes,  FIG.  9    depicts the transfer tray  506  configured to traverse along the guiding rail  504  to be positioned directly over the source container  304  and/or the destination container  310 , however, it is understood that the transfer tray  506  and/or the guiding rail  504  can be positioned differently. For example, the transfer tray  506  can be horizontally off-set from the source container  304  and/or the destination container  310  such that transfer tray  506  is positioned above and/or adjacent to, but not directly over, the source container  304  and/or the destination container  310  when traversing along the guiding rail  504 . In some embodiments, the guiding rail  504  and the transfer tray  506  can be between the containers (e.g., the source container  304  and the destination container  310 ) and the robots. 
     The fourth example transfer environment can include a packing robot  902 , which can be similar to the picking robot  302 , but configured to place objects into the destination container  310 . Instead of dropping objects into the destination container  310  via the stopper  508  as described above, the robotic system  100  can operate the packing robot  902  to pick the objects from the transfer tray  506  and place them into the destination container  310 . For example, the robotic system  100  can implement the motion plan to place the transfer tray  506  within a threshold distance from and/or over the destination container  310 , pick (e.g., grip and/or lift) the target object  112  thereon via the packing robot  902 , transfer/lower the target object  112  to a placement location, and then release the target object  112 . Accordingly, using the packing robot  902 , the robotic system  100  can increase control over the placement of the target object  112 . Thus, the robotic system  100  can reduce damage to the target object  112  and/or increase accuracy in placing/packing the target object  112 . Moreover, using the packing robot  902  and the transfer tray  506 , the robotic system  100  can reduce and/or eliminate horizontal transfer of the target object  112  via a robotic arm. Accordingly, the robotic system  100  can reduce piece loss caused by grip failure during transfer of the target object  112 . 
     Fourth Example Transfer States 
       FIGS.  10 A- 10 D  are top views illustrating a processing sequence for the fourth example transfer environment in accordance with one or more embodiments of the present technology.  FIGS.  10 A- 10 D  illustrate various states of the robotic system  100  of  FIG.  1    and/or the first target object  112  during the processing sequence. As illustrated in  FIG.  10 A , the robotic system  100  can control the source sensor  306  to generate an image data depicting the source container  304  and object(s) therein. Based on the image data, the robotic system  100  can process the image data to identify the first target object  112  and derive a motion plan to pick up, transfer and/or place the first target object  112 . According to the motion plan, the robotic system  100  can operate the picking robot  302  to pick the first target object  112  (by, e.g., gripping with the end-effector and/or lifting). Once the first target object  112  reaches a minimum height (e.g., as represented by a triggering event from the area sensors  502 ), the robotic system  100  can move the transfer tray  506  from the destination container  310  to the source container  304  (e.g., between locations adjacent to and/or over the destination container  310  and the source container  304 ). 
     As illustrated in  FIG.  10 B , the robotic system  100  can control the picking robot  302  to drop and/or place the first target object  112  onto the transfer tray  506  below the first target object  112 . With the transfer tray  506  over or within a threshold distance from the source container  304  and the destination container  310  exposed, the robotic system  100  can operate the destination sensor  308  to generate an image data depicting the destination container  310  and/or object(s) therein. Subsequently the robotic system  100  can move the transfer tray  506  and the first target object  112  thereon toward the destination container  310 . In some embodiments, the robotic system  100  can replace the source container  304  at the start location  114  after placing the transfer tray  506  below the first target object  112  and/or while the transfer tray  506  moves toward the destination container  310 . In other embodiments, the source container  304  can include multiple objects which can be selected as the new target object  402 . 
     As illustrated in  FIG.  10 C , the robotic system  100  can move the transfer tray  506  toward and/or over the destination container  310  and within a threshold distance from and/or under the end-effector of the packing robot  902 . The robotic system  100  can operate the destination sensor  308  to generate an image data depicting the first target object  112  on the transfer tray  506  and about/over the destination container  310 . According to the image data of the destination container  310  (i.e., illustrated in  FIG.  10 B ) and the image data of the first target object  112 , the robotic system  100  can derive a portion (e.g., a destination placement portion) of the motion plan for the packing robot  902 . The robotic system  100  can implement the motion plan using the packing robot  902  to pick the first target object  112  from the transfer tray  506 . 
     The robotic system  100  can also operate the source sensor  306  to generate an image data to identify a second target object  402  in the source container  304  and/or derive a corresponding portion (e.g., a picking portion) of a motion plan for the picking robot  302 . In some embodiments, the robotic system  100  can operate the source sensor  306  and the destination sensor  308  simultaneously. The robotic system  100  can implement the motion plan for the second target object  402 , thereby operating the picking robot  302  to pick the second target object  402 . In some embodiments, the robotic system  100  can operate the picking robot  302  and the packing robot  902  simultaneously to pick the corresponding objects. 
     As illustrated in  FIG.  10 D , the robotic system  100  can move the transfer tray  506  toward and/or over the source container  304 . When the transfer tray  506  reaches a predetermined location over or about the source container  304 , the picking robot  302  can place the second target object  402  onto the transfer tray  506 . The robotic system  100  can operate the packing robot  902  to place the first target object  112  in the destination container  310 . In some embodiments, the robotic system  100  can operate the picking robot  302  and the packing robot  902  simultaneously to place the corresponding objects. The robotic system  100  can repeat the states described above to transfer and pack multiple objects. The robotic system  100  can implement a method that corresponds to the above described states. 
       FIG.  10 E  is a flow diagram of a third example method  1000  for operating the robotic system  100  of  FIG.  1    in accordance with one or more embodiments of the present disclosure. The example flow diagram can represent processes and/or maneuvers executed by one or more units in the fourth example transfer environment. Accordingly, the third example method  1000 , or a portion thereof, can correspond to the motion plan for executing a task to transfer the target object  112  from the source container  304  to the destination container  310 . 
     The third example method  1000  can be similar to the method illustrated in  FIGS.  6 E and/or  8 E . For example, the processes represented by blocks  1002 ,  1004 ,  1006 ,  1008 ,  1010 ,  1012 ,  1016 ,  1018 , and  1020  can be similar to those represented by blocks  602 ,  604 ,  606 ,  608 ,  610 ,  612 ,  614 ,  618 , and  620 , respectively. Also, the processes represented by blocks  1002 ,  1004 ,  1006 ,  1008 ,  1010 ,  1012 ,  1016 ,  1018 , and  1020  can be similar to those represented by blocks  802 ,  804 ,  806 ,  808 ,  810 ,  812 ,  814 ,  818 , and  820 , respectively. 
     At block  1002 , the robotic system  100  can obtain image data depicting the source container  304  of  FIG.  9    and the contents therein (e.g., the target object  112  of  FIG.  5 A ) using the source sensor  306  of  FIG.  9   . At block  1004 , the robotic system  100  can analyze the image data to identify, detect, and locate the target object  112  based on analyzing the image data. At block  1006 , the robotic system  100  can derive a picking portion of the motion plan based on detecting and/or locating the target object  112 . As described above, the robotic system  100  can derive the picking portion for operating the picking robot  302  of  FIG.  9    and/or the transfer tray  506  of  FIG.  9    to pick the target object  112  and place the target object  112  on the transfer tray  506 . At block  1008 , the robotic system  100  can pick the target object  112  via the picking robot  302  based on the picking portion (e.g., by communicating the motion plan and/or the associated commands/settings from the processors  202  to the picking robot  302  and executing the motion plan via the picking robot  302 ). At block  1010 , the robotic system  100  can determine a clearing event by tracking a height of the end-effector while implementing the motion plan and/or by detecting an exit event using the area sensors  502 . At block  1012 , using the clearing event as a trigger, the robotic system  100  can implement a portion (e.g., a source transfer portion) of the motion plan to move the transfer tray  506  toward and/or over the source container  304  such that the transfer tray  506  is within a threshold distance from and/or directly under the picked target object  112 . 
     For the third example method  1000 , at block  1014 , the robotic system  100  can obtain image data depicting the destination container  310  via the destination sensor  308 . The robotic system  100  can generate the image data when the transfer tray is within a threshold distance and/or over the source container  304 . For example, the robotic system  100  can generate 2D/3D images of the task location  116  of  FIG.  1    using the destination sensor  308 . The image data may be received by the one or more processors  202  of  FIG.  2   . The robotic system  100  may obtain image data before, while, or after placing the target object on the transfer tray, as illustrated at block  1016 . The robotic system  100  can implement a portion of the motion plan to place/drop the target object  112  on the transfer tray  506 , such as by operating the picking robot  302  to lower the target object  112  and/or by releasing the target object  112  from the end-effector. At block  1018 , the robotic system  100  can implement a portion of the motion plan to move the transfer tray  506  and the target object  112  thereon toward and/or over the destination container  310 . At block  1020 , the robotic system  100  may implement a portion of the motion plan to replace the source container  304  and/or reload a new object (e.g., the new target object  402  of  FIG.  10 C ) at the start location  114  for the next task. In other embodiments, the source container  304  can include multiple objects which can be selected as the new target object  402 . 
     Additionally, at block  1022 , the robotic system  100  can generate image data depicting the target object  112  on the transfer tray  506  and over/within a threshold distance from the task location  116 . The robotic system  100  can generate the image data when the transfer tray  506  is over or within a threshold distance from the destination container  310 . At block  1024 , based on the image data of the destination container  310  and/or the image data of the target object  112 , the robotic system  100  can derive a destination placement portion of the motion plan for the packing robot  902 . At block  1026 , the robotic system  100  can pick the target object  112  from the transfer tray  506  by implementing a portion of the packing motion plan using the packing robot  902 . As illustrated at block  1028 , the robotic system  100  can place the picked target object  112  in the destination container  310  via the packing robot  902 . The robotic system  100  can implement a portion of the packing motion plan to place the target object  112  after moving the transfer tray from the destination container  310  toward the source container (block  1012 ). 
       FIGS.  11 A- 11 C  are perspective views of example transfer trays (e.g., transfer tray  506  of  FIG.  5 A ) in accordance with one or more embodiments of the present disclosure.  FIG.  11 A  illustrates a belt conveyor transfer tray  1102  configured to laterally transfer objects between locations above the source container  304  and the destination container  310 . In some embodiments, the belt conveyor transfer tray  1102  itself can move along the guiding rail  504 . Once the belt conveyor transfer tray  1102  reaches a targeted location over and/or within a threshold distance from the destination container  310 , the robotic system  100  can operate the belt conveyor to drop the target object  112  instead of using the stopper  508  of  FIG.  5 A  or  FIG.  7 A  to engage the target object  112 . 
     In other embodiments, the belt conveyor transfer tray  1102  can be static and extend between the source container  304  and the destination container  310 , and the belt conveyor transfer tray  1102  can move the belt thereon to laterally transfer the target object  112  from the source container  304  and the destination container  310 . The belt conveyor transfer tray  1102  can operate without the stopper  508 . Moreover, the belt conveyor transfer tray  1102  can horizontally transfer the target object  112  thereon while minimizing stops, change in directions, and/or acceleration events. 
       FIG.  11 B  illustrates a slotted transfer tray  1104  configured to laterally transfer objects across the source container  304  and the destination container  310 . The slotted transfer tray  1104  can be operably coupled to and move along the guiding rail  504 . The slotted transfer tray  1104  can include slots  1106  (e.g., linear depressions) on a top surface thereof. The slots  1106  can extend parallel to the direction of movement of the slotted transfer tray  1104 . 
     In some embodiments, the robotic system  100  can include a fork-style stopper  1108  along with the slotted transfer tray  1104 . The fork-style stopper  1106  can include extensions  1110  that extend downward and into the slots  1106 . Accordingly, the fork-style stopper  1108  can extend below the target object  112 , thereby reducing failures. Further, the slots  1106  can prevent the target object  112  from sticking to the tray  1104 , further reducing failures. Also, the slots  1106  can provide an escape path for air while the target object  112  is placed/dropped onto the slotted transfer tray  1104 . Accordingly, the slotted transfer tray  1104  can reduce/remove unintended movement of the target object  112 , along with the associated failures, caused by air resistance or air flow during placement of the target object. 
       FIG.  11 C  illustrates a perforated-surface transfer tray  1112  configured to laterally transfer objects across the source container  304  and the destination container  310 . The perforated-surface transfer tray  1112  can include a perforated layer  1114  on the top surface thereof. The perforated layer  1114  can include depressions on the top surface. In some embodiments, the perforated layer  1114  can include rubber or resin type material. Accordingly, the perforated layer  1114  can provide increased friction, thereby reducing the likelihood of the target object  112  slipping off the tray  1112  during transfer. Moreover, the perforated layer  1114  and the depressions in the top surface of the perforated-surface transfer tray  112  can prevent any suction cups on grippers from gripping the tray  1112 . 
     Additionally or alternatively, one or more sensors may be attached to and/or integral with the transfer tray  506 . Some examples of the tray sensors can include visual code sensors (e.g., barcode sensor and/or QR sensors), cameras, weight/mass sensor, RFID sensors, contact sensors, etc. In some embodiments, the transfer tray  506  can include an identification sensor (e.g., the RFID sensor or the visual code sensor) that identifies the object placed on the tray. The transfer tray  506  may similarly sense weight/mass object, absence/presence of the object, and/or other aspects of the placed object via the tray sensor(s). The transfer tray  506  can use the sensor output to identify the placed object and/or track the status of the motion plan or the corresponding actions. 
     Conclusion 
     The above Detailed Description of examples of the disclosed technology is not intended to be exhaustive or to limit the disclosed technology to the precise form disclosed above. While specific examples for the disclosed technology are described above for illustrative purposes, various equivalent modifications are possible within the scope of the disclosed technology, as those skilled in the relevant art will recognize. For example, while processes or blocks are presented in a given order, alternative implementations may perform routines having steps, or employ systems having blocks, in a different order, and some processes or blocks may be deleted, moved, added, subdivided, combined, and/or modified to provide alternative or sub-combinations. Each of these processes or blocks may be implemented in a variety of different ways. Also, while processes or blocks are at times shown as being performed in series, these processes or blocks may instead be performed or implemented in parallel, or may be performed at different times. Further, any specific numbers noted herein are only examples; alternative implementations may employ differing values or ranges. 
     These and other changes can be made to the disclosed technology in light of the above Detailed Description. While the Detailed Description describes certain examples of the disclosed technology as well as the best mode contemplated, the disclosed technology can be practiced in many ways, no matter how detailed the above description appears in text. Details of the system may vary considerably in its specific implementation, while still being encompassed by the technology disclosed herein. As noted above, particular terminology used when describing certain features or aspects of the disclosed technology should not be taken to imply that the terminology is being redefined herein to be restricted to any specific characteristics, features, or aspects of the disclosed technology with which that terminology is associated. Accordingly, the invention is not limited, except as by the appended claims. In general, the terms used in the following claims should not be construed to limit the disclosed technology to the specific examples disclosed in the specification, unless the above Detailed Description section explicitly defines such terms. 
     Although certain aspects of the invention are presented below in certain claim forms, the applicant contemplates the various aspects of the invention in any number of claim forms. Accordingly, the applicant reserves the right to pursue additional claims after filing this application to pursue such additional claim forms, in either this application or in a continuing application.