Methods and systems for automated transportation of items between variable endpoints

[0001] The present application relates generally to transportation of items and, more particularly, to automated methods and systems for transporting items between variable endpoints.

[0002] An automated system for transporting items between variable endpoints in accordance with one or more embodiments includes a guidance system for identifying the endpoints and at least one autonomous mobile robot interacting with the guidance system for automatically moving items between the endpoints. The at least one robot is configured to (a) collect an item to be transported at a source endpoint, (b) travel to a destination endpoint utilizing the guidance system to locate the destination endpoint, (c) deliver the item to the destination endpoint, and (d) repeat (a) through (c) for a given set of items. The guidance system is dynamically reconfigurable to identify new endpoints.

[0003] A method of transporting items between endpoints in accordance with one or more embodiments includes the steps of: establishing a source endpoint and a destination endpoint; activating at least one autonomous mobile robot to automatically (a) travel to a source endpoint, (b) collect an item to be transported, (c) travel to the destination endpoint with the item, (d) deliver the item to the destination endpoint, and (e) repeat (a) through (d) for a given set of items; and changing the location of one or both of the source and destination endpoints, wherein the at least one robot dynamically adapts to changed endpoints to repeat steps (a)-(e).

[0009] Like or identical reference numbers are used to identify common or similar elements.

[0010] Various embodiments disclosed herein are generally directed to material handling methods and systems. In particular, automated methods and systems are provided for transporting items between variable endpoints. An automated system in accordance with one or more embodiments includes a guidance system for identifying the endpoints and one or more autonomous mobile robots or platforms interacting with the guidance system for automatically moving items between the endpoints. Each robot is configured to (a) collect an item to be transported at a source end point, (b) travel to a destination endpoint utilizing the guidance system to locate the destination endpoint, (c) deliver the item to the destination endpoint, and (d) repeat (a) through (c) for a given set of items. The guidance system is dynamically reconfigurable to identify new endpoints. The guidance system can mark a complete route or just the end points of a route for the robot.

[0011] Advantages of automated systems in accordance with various embodiments can include flexibility, minimal infrastructure, no programming needed, and adaptability to unstructured environments.

[0012] The automated system can be used across broad market segments. Automated systems in accordance with various embodiments can also be operated under a variety of conditions including the following. (1) The terrain is rough, e.g., outdoor environments where conventional material handling systems are difficult to use. (2) The surface over which material must travel cannot support heavy weight, e.g., the weight of trucks, forklifts or other mechanized solutions. (3) The workspace is unstructured and dynamic. In addition to most outdoor spaces, this description includes indoor spaces, where the workflow changes frequently or large objects (e.g., pallets) are often repositioned. (4) The pickup point or the drop off point or both, change during operations. (5) Obstruction of the workspace created by a fixed conveyor system is unacceptable. (6) Material must be moved long distances and system utilization is low to moderate. (7) The initial cost of the material-handling system is required to be low.

Platform

[0013] The form of an autonomous robot in a particular implementation can vary depending on payload and environmental factors. By way of example, if the robot operates on a flat surface inside a building, it can use a two-wheeled, differential drive mobility system. If it operates on a rough terrain, e.g., a construction site, it may use a tracked platform able to traverse inclines and loose soil.

Behaviors

[0014] The autonomous robots move items from a source or load point to a sink or unload point. The robot's basic behaviors depend on its relationship to the source and sink points and whether it is carrying a load. The following table describes some exemplary behaviors triggered by position and load status:

[0015]

Position	Load status	Behavior
Source	Loaded	Move toward sink
	Empty	Stop, wait to be loaded
Intermediate	[Don't	Proceed along the route until an
	care]	endpoint is reached
Sink	Loaded	Stop, wait to be unloaded
	Empty	Move toward source

[0016] Beyond the basic behaviors outlined in the table, autonomous robots in accordance with various embodiments may have additional behaviors that are activated at intermediate positions along the route. These behaviors deal with obstacles (including other robots) discovered along the way.

Queuing

[0017] In accordance with one or more embodiments, each autonomous robot includes a sensor or other mechanism for detecting the presence of other nearby robots. If a robot encounters an obstacle along its route, it either stops or attempts to go around the obstacle. However, if the obstacle is another robot then the robot stops, thus forming a queue. Queues develop near endpoints of the route when robots wait to be loaded or unloaded.

Avoidance

[0018] If a robot encounters an obstacle along a route that is not another robot, the robot may attempt to continue toward its destination by skirting the object. The robot can include a wide-angle range sensor (see below) to provide it knowledge of obstructions on and near its route. This may make it possible for the robot to depart from a direct route and then return once the obstacle has been passed. However, whether the robot attempts to go around an obstacle or wait for the obstacle to move is a user choice. In generally uncluttered environments, it will be safe for a robot to search for an alternate route by itself. In more complex environments—especially those with non-geometric hazards—finding a safe alternative to the marked route may not be safe. Thus the user can instruct the robot whether to wait when the route is blocked.

Sensing

[0019] Route: In accordance with one or more embodiments, robots can navigate between source and sink using a guidance system such as a beacon marking the route's endpoints or a continuous route marker.

[0020] The beacon can be active (e.g., an IR emitter) or passive (e.g., a pattern recognized by an onboard camera). If a beacon is used, each robot should maintain a line of sight between the beacons, i.e., both beacons should be visible to the robot at nearly all times. The robot moves directly from one beacon toward the other unless an obstacle intervenes as described above.

[0021] The beacons can establish a coordinate system, where the beacon is the origin of the system. Angular encoding can be used to specify the axes of the coordinate system. The coordinate system enables robots to queue along a particular ray whose origin is the beacon. Angle encoding can also enable other useful properties.

[0022] A route marker indicating a robot's path may be used in situations where either a line of sight between beacons does not exist or traveling in a straight path between beacons is not desired. For example, a route marker might enable a robot to avoid a ditch at a construction site.

[0023] The route marker can be a worker-positioned tape or line, e.g., comprising a retro-reflective material that enables the robot to acquire it at a distance. The tape or line need not be permanently installed on the floor.

[0024] The robot can illuminate the tape or line using, e.g., conventional IR LEDs. In one or more embodiments, the robot detects the tape or line using a position-sensitive detector composed of discrete components (i.e., not a camera) to servo on the tape or line. The detector measures the degree of retro-reflectivity in view to eliminate false positives.

[0025] In some embodiments, the robots servo on the line directly. In other embodiments, the robots can servo at any selected offset with respect to the line. Offset servoing enables two important properties. When placing the line to mark the robot's path, workers need not allow space between line and objects. Any time the robot finds its path partially blocked by an object, it will increase its offset from the line so that it can follow the line without colliding with the object. A second feature enabled by offset following allows two robots that meet while traveling along the line in opposite directions to avoid collision. When the robots determine that a collision is imminent, each can offset its position relative to the line. They can thus pass without obstructing each other.

[0026] Obstacles: In order to move safely along its route, each robot is equipped with a sensor such as a wide-angle range sensor.

[0027] Robot: Each robot can be equipped with a sensor able to distinguish between obstacles and other robots at relatively short range. By way of example, this sensor can be an active IR emitter on one robot that is detected by a receiver on the other robot. The components of this system on the two robots can be arranged such that the following robot detects the robot in front only when the two are physically close.

[0028] Load: To allow autonomous operation, each robot can further include a sensor capable of detecting when the robot carries a load. The robot uses the output from this sensor to decide whether to wait at an end point or traverse to the opposite endpoint (see table above).

[0029] Manipulation: Robots may optionally include a mechanism enabling a robot to load and unload itself.

[0030] User interface: The interface for each robot is preferably simple and intuitive such that the workers themselves are able to setup material handling system wherever necessary. In one or more embodiments, no programming is required.

[0031] Automated material handling systems can have a wide range of applications, including, by way of example, the following:

[0032]

	Current	Automated	System
Application	Practice	Solution	Advantages
Produce picker	Laborers in	Workers	The automated
conveyor	the field pick	establish	system
	produce and	routes for	eliminates the
	place it in a	one or more	time workers
	basket or	autonomous	spend in transit
	sling.	robots. The	and eliminates
	Periodically,	robots travel	the need to carry
	they carry	along crop	heavy loads.
	the	rows and stop
	produce	at the
	from the	collection
	field to a	point.
	truck or	Periodically a
	other	robot arrives
	collection	at the place
	point.	where a
		worker is
		picking. The
		worker places
		just-picked
		produce on
		the robot then
		continues
		picking.
Truck Loading	Trucks back	Robots move	The automated
	up to the	products into	system reduces
	loading dock.	the trucks. A	the time and
	Workers move	worker in the	number of
	items from a	loading area	workers needed
	warehouse or	places items	to load a truck.
	other facility	onto a robot	Reduced loading
	into the	and dispatches	time translates
	loading area.	it to the	directly into cost
	There the	correct truck.	savings
	items may be	A worker in	especially in
	staged into	the truck	situations where
	orders or	packs the	customers must
	loaded	truck.	pay the trucking
	directly onto		company for idle
	the trucks.		time while trucks
	In either case,		are loaded.
	workers make
	a large
	number of
	back and
	forth trips
	to move
	items into
	trucks.
Baggage	At small	Ticket agents	The automated
Handling	airports ticket	place luggage	system enables
	agents collect	on robots	more timely
	luggage onto	queued in the	departures by
	a tray or pull	ticket area.	reducing the
	cart as	Bags then	loading
	passengers	move	bottleneck. It also
	check in.	immediately	makes more
	Eventually,	to the	efficient use of
	a batch of	aircraft	airline personnel.
	bags is	loading area.	Bags can be
	hauled out		loaded onto the
	to the		airplane as
	airplane.		passengers
	Loading		arrive and need
	cannot begin		not be loaded en
	until the		mass just before
	batch arrives.		takeoff.
Contract	Work is	When a new	The automated
Manufacturing	typically	contract job	system improves
	performed on	begins routes	the efficiency of
	the	are established	low-volume
	subassemblies	between the	manufacturing by
	of a product at	various stations	providing the
	several	where the work	benefits of
	different	will be done.	automatic
	assembly	The robots	conveyor
	stations. The	automatically	systems where
	particular	carry	they cannot
	stations	subassemblies	now be used.
	involved and	from each
	the flow of	station to the
	work pieces	next.
	among them
	may change
	with each
	contract job.
	Because
	workflow is
	frequently
	scrambled,
	fixed
	conveyor
	systems
	cannot be
	used.
Stocking	Workers	Workers mark	The automated
shelves in	place	the start and	system eliminates
stores	merchandise	end points of	multiple round
	on stocking	a route. A	trips. Workers
	carts then	worker in the	need set up a
	push the	store's storage	route only once,
	carts to the	area loads	then the robot
	correct area	robots with	will follow it
	of the store.	the proper	however many
	Popular items	items. After	times necessary.
	or items that	the robots
	do not stack	have
	well may	delivered
	require	their cargo
	many trips.	to the proper
		areas (using
		an optional
		AutoOffLoad
		feature)
		workers can
		stock the
		shelves.
Construction	Obstructions	Workers set	The automated
site material	or soft	up a route for	system saves
delivery	surfaces at	robots to	time by relieving
	construction	follow. A	workers of the
	sites often	worker at one	need to manually
	prevent trucks	end of the route	cart material from
	from delivering	loads robots	the delivery truck
	material to the	with material,	to the work point.
	place where it	and a worker at
	will be used.	the work point
	In these cases	unloads them.
	workers may
	need to make
	repeated trips
	to carry or
	cart item from
	the delivery
	point to the
	work area.
Landscaping	Trucks filled	A route is	The automated
site material	with plants	established	system reduces
delivery	and other	with drop off	the time needed
	items arrive	points indicated.	to distribute
	at a	The robots are	plants at
	landscaping	loaded at the	landscaping
	site. Because	truck then	sites.
	trucks cannot	automatically
	drive on the	carry plants to
	lawn all	the proper point
	materials	and drop them
	must be	off.
	carried or
	handcarted
	to the places
	where they
	will be
	installed.
Debris removal	Workers	Robots	The automated
	tear out	continuously	system
	walls,	carry debris	eliminates the
	fixtures,	away from the	time workers
	and other	work area as	spend in transit
	items in	it is generated.	hauling debris.
	preparation		Because the
	for new		work area never
	construction.		becomes
	The work		cluttered with
	area becomes		debris
	filled with		demolition
	debris. Carts		proceeds
	are brought in,		more
	loaded with		efficiently.
	debris, and it
	is moved to a
	dumpster,
	usually
	located
	outdoors.
Consumer leaf	Removing	The	The automated
collection	fallen leaves	homeowner	system makes
	typically	places a	raking faster
	involves	beacon at the	and easier.
	raking the	point where
	leaves into a	the leaves are
	pile, placing	to be deposited.
	the pile on a	An automated
	wheelbarrow	robot repeatedly
	or tarp, then	travels between
	moving the	the leaf deposit
	wheelbarrow	point and the
	or tarp to a	place where the
	collection	owner is raking.
	point.	The robot
		dumps the
		leaves using
		an optional
		dumping
		mechanism.

[0033] FIGS. 1-4 illustrate various possible guidance systems that can be used by robots to locate endpoints in accordance with one or more embodiments. In FIG. 1, the guidance system comprises a SLAM navigation system that gives robots 10 a global coordinate frame. In this formulation destinations are coordinates, thus no physical markers are necessary.

[0034] As shown in FIG. 2, beacons or passive tags 12 visible from a large distance mark each possible destination. This method allows the robot to reach any inbox or outbox without the need of a global frame.

[0035] FIG. 3 shows a guidance system combining shorter-range beacons 12 with “highways” established by markers 14 attached to the floor to give the robots a rough global frame. This arrangement simplifies range sensor requirements compared to SLAM.

[0036] In FIG. 4, robots are guided by marker 16 laid on the ground, in some cases temporarily.

[0037] FIG. 5 is a block diagram of various components of an exemplary robot 10. The robot 10 includes a chassis and a drive subsystem 52 for maneuvering the chassis. It further includes a guidance subsystem 54 on the chassis for interacting with the guidance system. In some embodiments, the subsystem 54 includes one or more marker detecting sensors able to detect the position of a marker such as a retro-reflective tape laid on the ground. By way of example, the marker detecting sensors can each comprise a photodiode-based sensor and one or more radiation sources (e.g., LEDs) to servo on the marker.

[0038] In some embodiments, the guidance subsystem 54 comprises a plurality of beacons, each having a radio frequency or other (e.g., infrared) beacon transmitter. In this case, the guidance subsystem 54 includes one or more sensors for detecting signals from beacons.

[0039] The robot includes an obstacle detection subsystem 56 for detecting other robots and obstacles.

[0040] The robot includes a microprocessor-based controller subsystem 58 for controlling operation of the robot in performing programmed behaviors. A power supply 50 for all the subsystems can include one or more rechargeable batteries.

[0041] In some embodiments, the drive subsystem 52 takes the form of a differential drive comprising two coaxial wheels and a roller for balance. The wheels are driven together or independently by one or more motors and a drive train controlled by the controller subsystem 58.

[0042] The obstacle detection subsystem 56 can include one or more range sensors to detect other robots and obstacles. In some embodiments, the range sensor is a wide-angle (120 degree) range sensor. Raw range sensor data (in the form of a list of angle and range readings) supplied by the sensor is processed by a computer processor (e.g., a processor in the controller subsystem 58) to return the position of other robots and obstacles.

[0043] The controller subsystem 58 is configured (e.g., programmed) to perform various functions, including transporting items between endpoints. The controller subsystem 58 is responsive to the output of guidance subsystem 54 and the output of obstacle detection subsystem 56. The controller subsystem 58 controls the drive subsystem 52 to maneuver the robot to prescribed endpoint locations.

[0044] Having thus described several illustrative embodiments, it is to be appreciated that various alterations, modifications, and improvements will readily occur to those skilled in the art. Such alterations, modifications, and improvements are intended to form a part of this disclosure, and are intended to be within the spirit and scope of this disclosure. While some examples presented herein involve specific combinations of functions or structural elements, it should be understood that those functions and elements may be combined in other ways according to the present disclosure to accomplish the same or different objectives. In particular, acts, elements, and features discussed in connection with one embodiment are not intended to be excluded from similar or other roles in other embodiments. Additionally, elements and components described herein may be further divided into additional components or joined together to form fewer components for performing the same functions.

[0045] The processes the robots are programmed to perform as described above may be implemented in software, hardware, firmware, or any combination thereof. The processes are preferably implemented in one or more computer programs executing on the programmable controller subsystem, which includes a processor, a storage medium readable by the processor (including, e.g., volatile and non-volatile memory and/or storage elements), and input and output devices. Each computer program can be a set of instructions (program code) in a code module resident in a random access memory. Until required, the set of instructions may be stored in another computer memory (e.g., in a hard disk drive, or in a removable memory such as an optical disk, external hard drive, memory card, or flash drive) or stored on another computer system and downloaded via the Internet or other network.

[0046] Accordingly, the foregoing description and attached drawings are by way of example only, and are not intended to be limiting.