Control system and method for aircraft

Abstract

The present invention relates to a manipulation system and method for an aircraft. A workpiece manipulation system for high-precision manipulation of a workpiece by an aircraft is provided. The workpiece manipulation system includes a lifting mechanism coupled to the aircraft, an end effector, and a processor. The lifting mechanism includes one or more joint actuators that extend or retract the lifting mechanism relative to the aircraft. The end effector includes an end effector actuator that controls the operation of the end effector to manipulate the workpiece. The processor is coupled to the aircraft processor in communication and is configured to control the operation of the end effector actuator and one or more joint actuators. In operation, the processor provides feedback to the aircraft.

Description

Technical Field

[0001] The present invention relates generally to aircraft systems and, more particularly, to aircraft and aircraft systems capable of high-precision manipulation, transportation, and placement of workpieces. Background Art

[0002] Robotic arms have been proven to operate accurately around the clock under limited supervision (generally requiring minimal operator interaction after initial programming). In recent decades, robotic automation has developed to the point where robotic arms can be used to pick up and place workpieces with high reliability and millimeter accuracy. Although robotic arms have been developed to be highly reliable and effective, they have multiple disadvantages. For example, robotic arms are also expensive, occupy valuable facility real estate, and because they are limited to being bolted to the floor or sitting on tracks, a single facility typically requires multiple robotic arms to be installed adjacent to each other to serve a continuous production line. In some industries, precision gripping and placement of workpieces is important. For example, wet-lab automation requires the ability to manipulate microplates (e.g., microtiter plates) with millimeter accuracy, which is traditionally performed using robotic arms bolted to the ground or arranged on rigid linear tracks.

[0003] Compared to a high-precision robotic arm that can cost hundreds or thousands of dollars, an unmanned aerial vehicle ("UAV") with perception and comparable transport capabilities is an order of magnitude cheaper. In fact, commercial low-cost UAV development is an active and growing industry, where UAV technology has proven to be a valuable tool for mission profiles involving intelligence, surveillance, reconnaissance, and payload delivery. UAV companies continue to launch UAVs with more capabilities, and recently, UAVs have been used to manipulate and transport artifacts. For example, Amazon recently launched Amazon Prime Air TM , which is a UAV-based delivery system designed to safely deliver packages to customers.

[0004] The current generation of low-cost commercial off-the-shelf (COTS) UAVs (i.e., consumer UAVs) are already capable of performing relatively safe indoor operations. Therefore, UAVs are excellent candidates to replace robotic arms in warehouses, factories, and laboratories, which can provide automation and transportation of workpieces within a given facility. However, existing consumer UAVs have aerodynamic instabilities and inaccuracies that make such UAVs incapable of precise grasping and placement. In fact, modern consumer UAVs hover with an accuracy of about tens of centimeters, which can also be strongly affected by proximity to walls and tables, arm motion, and mechanical interactions between the arm and the environment.

[0005] Therefore, there is a need for a UAV equipped with an arm and an end effector that can manipulate, transport, and place workpieces in an environment (e.g., an indoor environment) with high precision. There is also a need for a workpiece manipulation system that can be modified to compensate for such aerodynamic instabilities and inaccuracies to provide increased endpoint-accuracy. As will be disclosed, the workpiece manipulation system (a) enhances the effective endpoint accuracy of the UAV, and (b) constrains how mechanical forces caused by the interaction between the end effector (e.g., a gripper) and the environment rebound onto the flight dynamics of the UAV. Summary of the invention

[0006] Disclosed herein are aircraft and aircraft systems capable of high-precision manipulation, transportation, and placement of workpieces, including workpiece manipulation systems for aircraft, and the like.

[0007] According to a first aspect, an aviation workpiece manipulation system for providing high-precision manipulation of a workpiece includes: an airframe; a plurality of rotor frames extending radially from the airframe; a plurality of propellers, each of the plurality of propellers being positioned at a distal end of one of the plurality of rotor frames and electrically coupled to an electronic speed controller (ESC) controlled by an aircraft processor; a lifting mechanism coupled to the airframe, wherein the lifting mechanism includes one or more joint actuators to extend or retract the lifting mechanism relative to the airframe; an end effector coupled to the lifting mechanism, wherein the end effector includes an end effector actuator to control operation of the end effector to manipulate the workpiece; and a second processor communicatively coupled to the aircraft processor and configured to control operation of the end effector actuator and the one or more joint actuators.

[0008] According to a second aspect, a workpiece manipulation system for an aircraft to provide high-precision manipulation of a workpiece includes: a lifting mechanism coupled to the aircraft, wherein the lifting mechanism includes one or more joint actuators to extend or retract the lifting mechanism relative to the aircraft; an end effector coupled to the lifting mechanism, wherein the end effector includes an end effector actuator to control the operation of the end effector to manipulate the workpiece; and a processor, which is communicatively coupled to the aircraft processor and is configured to control the operation of the end effector actuator and the one or more joint actuators.

[0009] In certain aspects, the lifting mechanism is a four-bar linkage having four connecting rods connected in a loop by four connecting joints.

[0010] In certain aspects, the lifting mechanism is coupled to the machine body at a first connection joint via a mounting structure.

[0011] In certain aspects, the one or more joint actuators are configured to pivot at least one of the four connecting rods about an axis of rotation of the first connecting joint.

[0012] In some aspects, one or more joint actuators include a first joint actuator and a second joint actuator, wherein the first joint actuator is configured to pivot one of the four connecting rods about the rotation axis of the first connecting joint, and the second joint actuator is configured to pivot another of the four connecting rods about the rotation axis of the first connecting joint.

[0013] In certain aspects, the lift mechanism is removably coupled to the machine body via the mounting structure.

[0014] In certain aspects, the lifting mechanism is rotatably coupled to the underside surface of the body via a mounting structure.

[0015] In some aspects, the mounting structure is a gimbal system.

[0016] In some aspects, the mounting structure is a U-shaped bracket.

[0017] In certain aspects, the end effector actuator and the one or more joint actuators each include a brushless DC back-driveable motor.

[0018] In certain aspects, the end effector is coupled to the lift mechanism via an arm frame.

[0019] In some aspects, the boom frame is a telescopic boom frame.

[0020] In certain aspects, the end effector includes one or more feedback sensors to provide feedback data to the second processor.

[0021] In certain aspects, the end effector includes an optical module communicatively coupled to the second processor.

[0022] In certain aspects, the optical module includes a first infrared (IR) camera and an IR laser projector.

[0023] In certain aspects, the optical module includes a second IR camera spaced apart from the first IR camera.

[0024] In certain aspects, the optical module further includes an RGB (red / green / blue) camera.

[0025] In certain aspects, the end effector includes a pressure sensor communicatively coupled to the second processor.

[0026] In some aspects, the pressure sensor is embedded in the cast rubber.

[0027] In certain aspects, the pressure sensor is positioned on an underside surface of the end effector.

[0028] In certain aspects, the pressure sensor is configured to detect the stable surface when the workpiece is positioned on the stable surface.

[0029] In certain aspects, the end effector includes a plurality of fiducial markers to assist in determining the position of the end effector.

[0030] In certain aspects, the second processor is configured via the optical module to track a plurality of fiducial markers.

[0031] In certain aspects, the end effector is removably coupled to the lift mechanism to enable the end effector to be exchanged with another end effector.

[0032] According to a third aspect, a workpiece manipulation system for an aircraft to provide high-precision manipulation of a workpiece includes: an end effector, which is shaped to guide the workpiece toward the end effector; and a lifting mechanism coupled to the aircraft, wherein the lifting mechanism includes a set of engagement legs, each of the engagement legs includes a first link, the first link is pivotally coupled to a second link, wherein the end effector is coupled to each engagement leg, wherein the lifting mechanism is configured to passively extend or retract relative to the aircraft when the end effector contacts a stable surface, wherein a linear elastic element couples a portion of the first link to a portion of the second link.

[0033] In certain aspects, each engagement leg is configured to move independently to allow the vehicle to move from side to side while maintaining contact between the end effector and the stable surface.

[0034] In some aspects, the linear elastic element is a rubber band.

[0035] In some aspects, the linear elastic element is a metal spring.

[0036] In certain aspects, the end effector is shaped to define a funnel feature to direct the workpiece toward the end effector.

[0037] In certain aspects, an end effector is pivotally coupled to each engagement leg.

[0038] Embodiments of the present invention relate to an aviation workpiece manipulation system that provides high-precision manipulation of a workpiece, which may include an airframe; a plurality of rotor frames extending radially from the airframe; a plurality of propellers, each of which is positioned at the distal end of one of the plurality of rotor frames and electrically coupled to an electronic speed controller (ESC) that can be controlled by an aircraft processor; a lifting mechanism coupled to the airframe, wherein the lifting mechanism includes one or more joint actuators to extend or retract the lifting mechanism relative to the airframe; an end effector coupled to the lifting mechanism, wherein the end effector includes an end effector actuator to control the operation of the end effector to manipulate the workpiece; and a second processor, the second processor is communicatively coupled to the aircraft processor and is configured to control the operation of the end effector actuator and the one or more joint actuators. The lifting mechanism may be a four-bar linkage having four connecting rods connected in a loop through four connecting joints. This can improve reliability. The lifting mechanism may be coupled to the airframe at a first connecting joint via a mounting structure, and wherein one or more joint actuators may be configured to pivot at least one of the four connecting rods about a rotation axis of the first connecting joint. One or more joint actuators include a first joint actuator and a second joint actuator, wherein the first joint actuator can be configured to pivot one of the four connecting rods about the rotation axis of the first connecting joint, and the second joint actuator can be configured to pivot another of the four connecting rods about the rotation axis of the first connecting joint. At least one of the end effector actuator and the one or more joint actuators includes a brushless DC reversible drive motor. This will enhance operation. The end effector may include one or more feedback sensors to provide feedback data to the second processor. The end effector may include an optical module that can be coupled to the second processor in a communicative manner. The end effector may include a pressure sensor that can be coupled to the second processor in a communicative manner. The end effector may include multiple reference marks to assist in determining the position of the end effector.

[0039] Another embodiment of the present invention relates to a workpiece manipulation system for an aircraft to provide high-precision manipulation of a workpiece, the workpiece manipulation system comprising a lifting mechanism coupled to the aircraft, wherein the lifting mechanism includes one or more joint actuators to extend or retract the lifting mechanism relative to the aircraft; an end effector coupled to the lifting mechanism, wherein the end effector includes an end effector actuator to control the operation of the end effector to manipulate the workpiece; and a processor, which is communicatively coupled to the aircraft processor and is configured to control the operation of the end effector actuator and the one or more joint actuators. The lifting mechanism can be a four-bar linkage having four connecting rods connected in a loop through four connecting joints. The lifting mechanism can be configured to be coupled to the aircraft at a first connecting joint via a mounting structure. The one or more joint actuators can be configured to pivot at least one of the four connecting rods about a rotation axis of the first connecting joint. One or more joint actuators include a first joint actuator and a second joint actuator, wherein the first joint actuator can be configured to pivot one of the four connecting rods about the rotation axis of the first connecting joint, and the second joint actuator can be configured to pivot another of the four connecting rods about the rotation axis of the first connecting joint. The lifting mechanism can be configured to be removably coupled to the aircraft via a mounting structure. The end effector may include an optical module that can be coupled to the processor in a communicative manner. The optical module includes a first infrared (IR) camera, an IR laser projector, and a second IR camera that can be spaced apart from the first IR camera. The optical module may further include an RGB (red / green / blue) camera. The end effector may include a pressure sensor that can be coupled to the processor in a communicative manner. The end effector may be removably coupled to the lifting mechanism so that the end effector can be exchanged with another end effector.

[0040] A workpiece manipulation system for an aircraft to provide high precision manipulation of a workpiece, the workpiece manipulation system may include: an end effector, the end effector being shaped to guide the workpiece toward the end effector; and a lifting mechanism coupled to the aircraft, wherein the lifting mechanism may include a set of engagement legs, each of the engagement legs may include a first link, the first link pivotally coupled to a second link, wherein the end effector may be coupled to each engagement leg, wherein the lifting mechanism may be configured to passively extend or retract relative to the aircraft when the end effector contacts a stable surface, wherein a linear elastic element couples a portion of the first link to a portion of the second link. At least one of the engagement legs may be configured to move independently to allow the aircraft to move from one side to the other while maintaining contact between the end effector and the stable surface. The end effector may be shaped to define a funnel feature to guide the workpiece toward the end effector. This may enhance performance. The end effector may be pivotally coupled to each engagement leg. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] The foregoing and other objects, features, and advantages of the devices, systems, and methods described herein will become apparent from the following description of specific embodiments thereof, as illustrated in the accompanying drawings, in which like reference numerals refer to like structures. The drawings are not necessarily to scale, emphasis instead being placed on illustrating the principles of the devices, systems, and methods described herein.

[0042] Figure 1a Example Instance Multirotor Vertical Take-Off and Landing (VTOL) UAV.

[0043] Figure 1b Example for Figure 1a Block diagram of an example aircraft control system for a VTOL UAV.

[0044] Figures 2a to 2c Example equipment with example workpiece manipulation system Figure 1a UAVs.

[0045] Figure 3 Example end effector for physically grasping an artifact.

[0046] Figure 4 Example diagram of an integrated architecture for an artifact manipulation system.

[0047] Figures 5a to 5c Example operation of the UAV as it travels toward and grasps a workpiece is illustrated.

[0048] Figure 6a 6d illustrate an example passive artifact manipulation system for use with a UAV. DETAILED DESCRIPTION

[0049] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. The components in the accompanying drawings are not necessarily drawn to scale, but the emphasis is placed on clearly illustrating the principles of the present embodiments. For example, the size of the elements may be exaggerated for clarity and convenience of description. In addition, whenever possible, the same reference numerals are used throughout the drawings to refer to the same or identical elements of the embodiments. In the following description, well-known functions or configurations are not described in detail because they may make the present invention difficult to understand as unnecessary details. The language in the specification should not be interpreted as indicating that any unclaimed element is essential to the practice of the embodiments.

[0050] Unless otherwise specified herein, the recording of numerical ranges herein is not intended to be restrictive, but refers to any and all numerical values ​​falling within the range individually, and each individual numerical value within such a range is incorporated into the specification as if it is individually recorded herein. The words "about", "approximately" or similar words will be interpreted as representing that a person of ordinary skill in the art will understand and that the intended purpose of the operation deviation is met when accompanying numerical values. Numerical ranges and / or numerical values ​​are only provided as examples herein, and do not constitute a limitation on the scope of the embodiments. The use of any example or exemplary language ("for example", "such as", or similar language) provided herein is only intended to better illustrate the embodiments, rather than limiting the scope of the embodiments. The language in the specification should not be interpreted as representing that any unclaimed element is essential to the practice of the embodiments.

[0051] In the following description, it is understood that terms such as "first", "second", "upper", "lower", "side", "front", "rear", and similar terms are words of convenience and should not be construed as limiting terms. Various data values ​​(e.g., voltage, seconds, etc.) provided herein may be replaced by one or more other predetermined data values ​​and therefore should not be considered limiting, but rather exemplary. For the present disclosure, the following terms and definitions shall apply:

[0052] The terms "aerial vehicle" and "aircraft" refer to machines capable of flight, including, but not limited to, fixed-wing aircraft, UAVs (unmanned aerial vehicles), variable-wing aircraft, and vertical take-off and landing (VTOL) aircraft.

[0053] The term "and / or" means any one or more of the items in the list connected by "and / or". As an example, "x and / or y" means any element in the three-element group {(x), (y), (x, y)}. In other words, "x and / or y" means "one or both of x and y". As another example, "x, y and / or z" means any element in the seven-element group {(x), (y), (z), (x, y), (x, z), (y, z), (x, y, z)}. In other words, "x, y and / or z" means "one or more of x, y and z".

[0054] The terms "circuit" and "circuitry" refer to physical electronic components (e.g., hardware) and any software and / or firmware ("code") that may configure, be executed by, and or otherwise be associated with the hardware. As used herein, for example, a particular processor and memory may comprise a first "circuit" when executing a first set of one or more lines of code, and may comprise a second "circuit" when executing a second set of one or more lines of code. As used herein, a circuitry is "operable" so as to perform a function so long as the circuitry includes the hardware and code (if either is necessary) required to perform the function - regardless of whether performance of the function is disabled or not enabled (e.g., by user-configurable settings, factory trim, etc.).

[0055] As used herein, the terms "communication" and "communicative" include the transmission of data from a source to a destination, and the delivery of data to a communication medium, system, channel, network, device, wire, cable, fiber, circuit, and / or link for transmission to a destination. The term "communication" as used herein means the data so transmitted or delivered. The term "communication" as used herein includes one or more of a communication medium, system, channel, network, device, wire, cable, fiber, circuit, and / or link.

[0056] As used herein, the terms "coupled," "coupled to," and "coupled with" all mean a relationship between or among two or more devices, equipment, files, circuits, elements, functions, operations, processes, procedures, media, components, networks, systems, subsystems, and / or means that constitutes any one or more of the following: (i) a connection, whether directly or through one or more other devices, equipment, files, circuits, elements, functions, operations, processes, procedures, media, components, networks, systems, subsystems, or means; (ii) a communication relationship, whether directly or through one or more other devices, equipment, files, circuits, elements, functions, operations, processes, procedures, media, components, networks, systems, subsystems, or means; and / or (iii) a functional relationship in which the operation of any one or more of the devices, equipment, files, circuits, elements, functions, operations, processes, procedures, media, components, networks, systems, subsystems, or means is dependent, in whole or in part, on the operation of any one or more of the others.

[0057] As used herein, the term "data" means any indicia, signal, sign, symbol, field, symbol set, representation, and any other physical form or forms representing information - whether permanent or temporary, whether visible, audible, acoustic, electrical, magnetic, electromagnetic, or otherwise manifested. The term "data" is used to represent predetermined information in one physical form, including any and all representations of the corresponding information in one or more different physical forms.

[0058] As used herein, the term "database" means an organization of related data, regardless of the manner in which the data or its organization is represented. For example, the organization of related data may be in the form of one or more of a table, a graph, a grid, a packet, a datagram, a frame, a file, an email, a message, a document, a report, a list, or any other form.

[0059] The term "exemplary" means "serving as an example, case, or illustration". The embodiments described herein are not limiting but merely exemplary. It should be understood that the described embodiments are not necessarily to be construed as preferred or advantageous over other embodiments. Furthermore, the terms "embodiments of the invention", "embodiments" or "invention" do not require that all embodiments of the invention include the discussed features, advantages or modes of operation.

[0060] The term "memory device" means computer hardware or circuitry that stores information for use by a processor. The memory device may be any suitable type of computer memory or any other type of electronic storage medium, such as, for example, read-only memory (ROM), random access memory (RAM), cache memory, compact disk read-only memory (CDROM), electro-optical memory, magneto-optical memory, programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), computer-readable medium, or the like.

[0061] The term "network" as used herein includes all types of networks and inter-networks, including the Internet, and is not limited to any particular network or inter-network.

[0062] The term "processor" means a processing device, apparatus, program, circuit, component, system, and subsystem, whether implemented in hardware, tangibly embodied software, or both, and whether or not programmable. The term "processor" includes, but is not limited to, one or more computing devices, hard-wired circuits, signal modification devices and systems, devices and machines for controlling systems, central processing units, programmable devices and systems, field programmable gate arrays, application specific integrated circuits, systems on chips, systems including discrete elements and / or circuits, state machines, virtual machines, data processors, processing facilities, and any combination of the foregoing. The processor may be, for example, any type of general purpose microprocessor or microcontroller, a digital signal processing (DSP) processor, an application specific integrated circuit (ASIC). The processor may be coupled to or integrated in a memory device.

[0063] Disclosed herein is an aircraft configured to achieve millimeter precision grasping and placement of workpieces via a workpiece manipulation system. The endpoint accuracy of the workpiece manipulation system can be greatly enhanced by utilizing the contact between the end effector and the static workpiece (or other stable surface). It is understood that the endpoint accuracy refers to the accuracy of the distal end (e.g., the end effector 210) of the arm frame 206 in terms of targeting and engaging the workpiece 214. For example, the workpiece manipulation system can be designed to be mounted on a gimbal and can provide the feedback required to stabilize the position of the aircraft, which reduces the dependence on the aircraft manufacturer and broadens the future commercial capabilities. The workpiece manipulation system enhances the accuracy and grasping of traditional UAVs in a variety of ways. First, the workpiece manipulation system reduces the impact of hovering changes by causing contact with a stable surface and acting as a suspension between the end effector and the UAV. Second, the lifting mechanism and the end effector provide information about the environment and the workpiece to the UAV through various feedback sensors to guide the UAV to approach the workpiece.

[0064] As will be discussed, the workpiece handling system can be configured as a retrofit system to attach to any aircraft capable of carrying the weight of its system, creating an ever-improving, low-cost aircraft for future use. The workpiece handling system can include a separate processor to direct the aircraft's controller to schedule to facilitate precise pick-and-placement of workpieces. The workpiece handling system of the present disclosure can be used in conjunction with a variety of aircraft configurations, including multi-rotor consumer VTOL UAVs, etc.

[0065] Aircraft suitable for workpiece handling systems include Figure 1a1. As shown, UAV 100 generally includes a body 102 (e.g., a fuselage or other structure), a plurality of rotor gantry 104 (e.g., longitudinal gantry) extending radially from body 102, landing gear 110, and a plurality of propellers 108. Although multi-rotor VTOL UAVs are illustrated throughout the figures, the teachings of the present disclosure may be equally applicable to other aircraft, including fixed-wing aircraft.

[0066] The airframe 102 may be coupled to the proximal end of each of the plurality of rotor frames 104 so that the distal ends of the plurality of rotor frames 104 extend radially from the airframe 102. The airframe 102 and the plurality of rotor frames 104 may be manufactured as a unit, or as separate components coupled to each other. The distal end of each of the plurality of rotor frames 104 may be coupled to a propeller 108, each propeller 108 being exemplified as a lift motor 108a coupled to a propeller 108b and configured to drive / rotate the propeller 108b. Each of the plurality of propellers 108 is positioned at the distal end of the rotor frame 104 and is oriented so that the thrust direction is downward (relative to the airframe 102). The lift motor 108a may be an electric motor controlled via an electronic speed controller (ESC) 106. Thus, the ESC 106 may also be provided, for example, adjacent to the lift motor 108a and integrated (or otherwise coupled) at the distal end of the rotor frame 104. Although the UAV 100 is illustrated as having six propellers 108 (i.e., a hexacopter), those skilled in the art will appreciate that more or fewer propellers 108 may be employed to achieve the desired functionality and, for example, depending on thrust requirements.

[0067] Although the lift motor 108a is illustrated as being at the distal end of each frame 104, the lift motor 108a (or a single lift motor 108a) may instead be positioned at the body 102 and configured to drive (rotate) the one or more propellers 108b via a gearbox and / or drive shaft between the lift motor 108a and the one or more propellers 108b. Further, although each frame 104 is illustrated as having only a single propeller 108, multiple propellers 108 may be provided at the distal end of each frame 104. For example, a cross-member may be positioned at the distal end of each frame 104 and arranged to space the propellers 108 from each other (e.g., perpendicular to the length of the frame 104) or otherwise prevent interference between the propellers 108b (e.g., a staggered / overlapping configuration). Components of the UAV 100 may be made of metal, composite materials, or a combination thereof. To prevent mechanical interference with the workpiece handling system, the landing gear 110 may include a plurality of posts (e.g., at the distal end of each frame) positioned along the periphery of the UAV 100. The posts of the landing gear 110 and the plurality of rotor frames 104 may be manufactured as a unit, or as separate components coupled to each other.

[0068] Figure 1b A block diagram of an example aircraft control system for the UAV 100 is illustrated. The aircraft control system is configured to control various aircraft components and functions of the UAV 100. As shown, the UAV 100 includes one or more aircraft processors 116, an artifact manipulation system 114, a flight controller 120, a wireless transceiver 122, and a navigation system 124 communicatively coupled to at least one memory device 118. The aircraft processor 116 may be configured to perform one or more operations based at least in part on instructions (e.g., software) and one or more databases stored in the memory device 118 (e.g., a hard drive, flash memory, or the like).

[0069] The aircraft control system may further include other desired services, such as a wireless transceiver 122 coupled to the antenna 112 to communicate data between the UAV 100 and a remote device 130 (e.g., a portable electronic device such as a smart phone, tablet computer, and laptop computer) or other controller (e.g., a base station). For example, the UAV 100 may communicate data (processed data, unprocessed data, etc.) with the remote device 130 over a network 128. In certain aspects, the wireless transceiver 122 may be configured to communicate using one or more wireless standards, such as Bluetooth (e.g., short wavelength ultra-high frequency (UHF) radio waves in the industrial, scientific, and medical (ISM) band of 2.4 to 2.485 GHz), near field communication (NFC), Wi-Fi (e.g., the 802.11 standard of the Institute of Electrical and Electronics Engineers (IEEE)), etc. The remote device 130 may facilitate monitoring and / or control of the UAV 100 and its payload(s), including the workpiece manipulation system 114 and the ISR payload 126 .

[0070] The aircraft processor 116 may be operably coupled to the flight controller 120 to control the operation of various actuators (e.g., those controlling the movement of any flight surface) and / or lift motors 108a (e.g., via the ESC 106) in response to commands from an operator, an autopilot, a navigation system 124, or other high-level systems via a wireless transceiver 122. In some aspects, the aircraft processor 116 and the flight controller 120 may be integrated into a single component or circuit. In operation, the flight controller 120 may dynamically (i.e., in real time or near real time) and independently adjust the thrust from each lift motor 108a on each rotor frame 104 via the ESC 106 during various phases of flight (e.g., takeoff, cruise, landing) to control the roll, pitch, or yaw of the UAV 100. In other words, the flight controller 120 may independently control each lift motor 108a on a given rotor frame 104 to produce the desired lift thrust of each lift motor 108a. For example, when using a rotor with rotor blades (e.g., propellers), the flight controller 120 can change the revolutions per minute (RPM) of the rotor and / or change the pitch of the rotor blades when desired. Specifically, the lift motor 108a can be controlled by adjusting the power supplied to each electric motor from a power source (e.g., a battery pack or battery bank) via the ESC 106.

[0071] The aircraft processor 116 may be operably coupled to a navigation system 124, which may include a global positioning system (GPS) 124a, which is communicatively coupled to an inertial navigation system (INS) 124b and / or an inertial measurement unit (IMU) 124c (which may include one or more gyroscopes and accelerometers). The GPS 124a gives an absolute drift-free position value, which may be used to reset an INS solution, or may be blended with the INS solution by utilizing a mathematical algorithm such as a Kalman filter. The navigation system 124 may communicate inertial stabilization data, etc. to the aircraft processor 116, which may be used to facilitate operation of the workpiece manipulation system 114.

[0072] To collect data and / or monitor an area, the UAV 100 may be further equipped with an intelligence, surveillance, and reconnaissance (ISR) payload 126, which includes, for example, one or more cameras 126a (e.g., optics for recording or capturing images and / or video, including light detection and ranging (LIDAR) devices), audio devices 126b (e.g., microphones, echolocation sensors, etc.), and other sensors 126c to facilitate ISR functionality and provide ISR data (e.g., photos, videos, audio, sensor measurements, etc.). The ISR payload 126 is operably coupled to the aircraft processor 116 to facilitate communication of ISR data between the ISR payload 126 and the aircraft processor 116. The ISR data may be used to navigate the UAV 100 and / or control the operation of the workpiece manipulation system 114. The ISR payload 126 may be rotatably and pivotally coupled to, for example, an underside surface of the airframe 102 (or another structural member, such as the rotor frame 104) via a gimbal system to enable the ISR payload 126 to be more easily oriented downward to monitor objects below and / or above the ground. Data may be dynamically or periodically communicated from the UAV 100 to a remote device 130 over a network 128 via the wireless transceiver 122, or stored to the memory device 118 for later access or processing.

[0073] The aircraft processor 116 may be operably coupled to an indoor positioning system 132 that measures the position of the UAV 100 in the environment based on sensor readings and / or a known navigational map (e.g., a map of the environment reflecting obstacles and / or boundaries) that may be loaded and stored to the UAV 100 (e.g., at a memory device 118). The indoor positioning system 132 may include or be communicatively coupled to various sensors, such as motion capture sensors, radio beacons, infrared sensors, acoustic sensors, etc. In certain aspects, the indoor positioning system 132 may utilize ISR data from the ISR payload 126 to determine the position of the UAV 100 in the environment.

[0074] The aircraft processor 116 may be operably coupled to the workpiece handling system 114 to provide bidirectional communication between the workpiece handling system 114 (e.g., its processor and / or sensors) and the aircraft processor 116. In operation, the aircraft processor 116 may communicate target relative stabilization data to the workpiece handling system 114 and receive fine position instructions / data from the workpiece handling system 114. For example, instructions may be communicated from the aircraft processor 116 to the workpiece handling system 114 based at least in part on instructions from an operator, an autopilot, a navigation system 124, an indoor positioning system 132, an ISR payload 126, or other higher-level systems. Further, normal positioning and attitude / rate inputs to the flight controller 120 may be augmented by the aircraft processor 116 with finer scale inputs based at least in part on feedback from the workpiece handling system 114 in contact with a surface and position sensing of the workpiece to be grasped and placed.

[0075] The UAV 100 equipped with the example workpiece manipulation system 114 is illustrated in Figures 2a to 2c middle. Specifically, Figure 2a The workpiece manipulation system 114 is illustrated in an extended state, and Figure 2b The workpiece handling system 114 is illustrated in a stowed position (e.g., when the UAV 100 is navigating to a waypoint), and Figure 2cA side view illustrating contact between an end effector 210 and a stabilizing surface 216 is illustrated. The workpiece manipulation system 114 generally includes a mounting structure 202, a lift mechanism 204, an arm frame 206, one or more joint actuators 208, and an end effector 210. As shown, the workpiece manipulation system 114 may be rotatably and pivotally coupled to the UAV 100 via the mounting structure 202, which is coupled to an underside surface of the body 102. The mounting structure 202 may be fixed or configured to rotate relative to the body 102 (e.g., about an axis perpendicular to the XY plane). The mounting structure 202 may be, for example, a gimbal system or a U-shaped bracket.

[0076] The lifting mechanism 204 is exemplified as a four-bar linkage, which is a movable closed chain linkage having four main bodies (e.g., connecting rods 204a, 204b, 204c, 204d) connected in a ring by four joints (e.g., connecting joints 218a, 218b, 218c, 218d). Specifically, as shown, the first connecting joint 218a pivotally couples the first connecting rod 204a to the fourth connecting rod 204d. The second connecting joint 218b pivotally couples the first connecting rod 204a to the second connecting rod 204b. The third connecting joint 218c pivotally couples the second connecting rod 204b to the third connecting rod 204c. Finally, the fourth connecting joint 218d pivotally couples the third connecting rod 204c to the fourth connecting rod 204d. Each connecting joint can utilize, for example, a pivot pin, which is fixed by one or more pin holes or pin grooves.

[0077] The four-bar linkage may be a planar four-bar linkage in which the connecting joints are configured so that the connecting rods 204a, 204b, 204c, 204d move in the same (or parallel) plane. Although the lifting mechanism 204 is illustrated as a four-bar linkage, additional connecting rods may be provided to alleviate jamming or binding of the lifting mechanism 204 as it traverses the entire range of motion. For example, a fifth connecting rod may be pivotally connected to the second and fourth connecting rods 204b, 204d via a pair of toggles such that the fifth connecting rod is parallel to the first and third connecting rods 204a, 204c.

[0078] The end effector 210 can be coupled to the lifting mechanism 204 via the arm frame 206, and the arm frame 206 can be coupled to the lifting mechanism 204 at the second connection joint 218b. In some aspects, the arm frame 206 and the second connecting rod 204b can be formed as a single structure. The function of the arm frame 206 is to increase the distance between the end effector 210 and the lifting mechanism 204. Therefore, the arm frame 206 can be a telescopic frame, which can use an actuator assembly, such as a ball screw / nut assembly driven by an electric motor or other actuator (e.g., to adjust the length). Various hardware, such as the mounting structure 202, the connecting rods 204a, 204b, 204c, 204d, and the arm frame 206, can be made of one or more lightweight materials, including metals, metal alloys, plastics (e.g., 3D printed plastics) and / or composite materials. Most of the mass of the workpiece manipulation system 114 can be attributed to the joint actuators 208 positioned near the body 102 of the UAV 100.

[0079] A pair of joint actuators 208a, 208b may be coupled to the mounting structure 202 and the lifting mechanism 204 at the first joint 218a to raise and lower the arm frame 206 (and the end effector 210) relative to the body 102. For example, the first joint actuator 208a may be configured to drive the fourth connecting rod 204d so that one end thereof (i.e., the end adjacent to the first joint 218a) pivots about the rotation axis (identified by the pivot axis A) of the first joint 218a, and the second joint actuator 208b may be configured to drive the first connecting rod 204a so that one end thereof pivots about the rotation axis of the first joint 218a.

[0080] The joint actuator 208 may employ, for example, a brushless DC reversible drive motor. In operation, the two joint actuators 208a, 208b may be independently controlled to raise and lower the end effector 210 and adjust the angle of the arm frame 206 relative to the UAV 100 via the lifting mechanism 204. In order to minimize the friction and inertia rebounding onto the lifting mechanism 204, the joint actuator 208 may employ a small gear ratio (e.g., 10:1 or less). Each joint actuator 208a, 208b may include a motor drive circuit controlled by the workpiece manipulation processor 402. The joint actuator 208 may be driven by high-bandwidth current control, which enables the joint actuator 208 to approach the performance of an ideal torque source.

[0081] The workpiece manipulation system 114 may employ direct-drive and impedance control. Because the lifting mechanism 204 is very stiff and has low inertia, force control of the end points of the arm frame 206 (e.g., the end effector 210) may be performed using only the inverse Jacobian of the lifting mechanism 204 to relate the end point forces to the required motor torques. This enables the workpiece manipulation system 114 to control the mechanical impedance of the lifting mechanism 204 by giving motor torque commands in response to the motion feedback of the lifting mechanism 204. For example, stiffness is controlled by commanded force as a function of position displacement, while damping is controlled by commanded force as a function of velocity displacement. Appropriate selection of arm impedance will enable the lifting mechanism 204 to control the contact characteristics of the end effector 210 and the workpiece 214. The arm impedance may also provide a stabilizing force to the UAV 100, which will reduce variations in the position of the UAV 100 caused by air flow, measurement errors, and other disturbances.

[0082] The endpoint accuracy of the workpiece manipulation system 114 can be greatly enhanced by utilizing the contact between the end effector 210 and the stable surface 216. For example, consider a workpiece 214 resting on a flat stable surface 216. Placing the end effector 210 directly on the workpiece 214 would require accurate positioning of six axes - three Cartesian axes and three rotational axes. On the other hand, the workpiece manipulation system 114 can explicitly contact the stable surface 216 before approaching the workpiece 214, thereby utilizing the stable surface 216 to orient and stabilize the three degrees of freedom of the end effector 210 (i.e., vertical displacement and two rotational degrees of freedom). Active feedback control can ensure constant contact with the stable surface 216 as the UAV 100 moves the last few centimeters (identified as direction A) toward the workpiece 214.

[0083] like Figure 2c In the example, the workpiece manipulation system 114 can move the end effector 210 along a stable surface 216 (e.g., a table, or other static machine surface) relative to the UAV 100 and toward the workpiece 214. The lift mechanism 204 acts as a spring-damper suspension 220 to provide active feedback and maintain contact between the lift mechanism 204 and the stable surface 216 near the workpiece 214. The dynamic capabilities of the lift mechanism 204 effectively act as a spring-damper suspension 220 between the end effector 210 and the UAV 100 to maintain contact between the end effector 210 and the stable surface 216 while decoupling the dynamics of the UAV 100 from the interactive forces at the end effector 210.

[0084] Additional sensing in the lift mechanism 204 and the end effector 210 can provide the UAV 100 with information to position itself relative to the workpiece 214, as well as to navigate toward and grasp the workpiece 214. For example, as will be discussed, the end effector 210 can be configured with a depth camera and / or one or more tactile sensors to measure the relative orientation of the end effector 210 relative to the workpiece 214. Information from one or more sensors reflecting, for example, the motion state of the workpiece manipulation system 114 can be communicated to the aircraft processor 116 to provide information about the precise position of the UAV 100 relative to the stable surface 216 and the workpiece 214. This information enhances the positioning and navigation of the UAV 100 to enable precise grasping of the workpiece 214. For example, after the workpiece 214 is grasped by the end effector 210, the lift mechanism 204 can stabilize the workpiece 214 during transportation to prevent, for example, any potential sloshing and spillage. For example, if the workpiece 214 is grasped with the arm 206 partially extended, the end of the arm 206 will have sufficient actuation range of motion to minimize acceleration of the workpiece 214 as the UAV 100 moves through the environment. Such stabilization control may be performed using a single spring damper gain setting selected, for example, using optimization and without actively reading accelerometer data, or by reading accelerometer data on the UAV 100 and / or the workpiece 214 for active vibration identification and suppression. In one example, the lift mechanism 204 may exhibit a substantially Figure 2b The stowed position of the UAV 100, whereby the lifting mechanism 204 and / or the end effector 210 are fixed in place. This stowed configuration brings the arm frame 206 and the workpiece 214 close to the center of mass of the UAV, which provides the most favorable flight dynamics for the UAV 100.

[0085] The end effector 210 is the portion of the workpiece manipulation system 114 that interacts with the workpiece 214 and the environment. The end effector 210 suitable for manipulating, transporting, and placing the workpiece 214 includes a gripper, a magnet, and a vacuum cup. For example, in the case where the UAV 100 needs to pick up the workpiece 214, a gripper can be used as the end effector 210. In the case where the UAV 100 must perform other manufacturing operations, the end effector 210 may include tools such as brushes, cutting tools, drills, sanders, screwdrivers, spray guns, and welding guns. The end effector 210 may further include other devices to monitor the environment, such as collision avoidance sensors and cameras.

[0086] Figure 3An example end effector 210 of a gripper configured to physically and reliably grasp a workpiece 214 is illustrated. As shown, the end effector 210 generally includes a base 314 and a set of finger members 302 pivotally attached to the base 314, wherein the base 314 is pivotally coupled to the arm frame 206. The end effector 210 includes one or more end effector actuators 212 to selectively control the finger members 302. For example, each finger member 302 may include gearing teeth at one end (e.g., where it is coupled to the base 314) that mesh with a drive gear driven by the end effector actuator 212. The end effector actuator 212 may utilize, for example, a brushless DC back-drivable motor to drive (i.e., rotate) a gear that meshes with corresponding gear teeth of two finger members 302 at a pivot point.

[0087] The shape of the end effector 210 (e.g., the finger member 302) can be designed to take advantage of the shape of a particular workpiece 214, which is illustrated as a rectangular prism, to minimize the actuation degrees of freedom of the end effector 210. For example, as shown, the finger member 302 is shaped to correspond to the longitudinal sides of the workpiece 214, with the tip bent inward to prevent the workpiece 214 from sliding outward (i.e., away from the base 314). In some aspects, the finger member 302 can include a pivot joint along its length to provide a fully articulated finger member.

[0088] The contact surface between the finger member 302 and the workpiece 214 may be further shaped to increase friction / engagement. For example, the workpiece 214 may include one or more protrusions (or depressions) to match corresponding depressions (or protrusions) on the end effector 210 (e.g., the finger member 302 or the base 314). The finger member 302 may be lined or configured with a low friction surface (e.g., rubber) to enhance its grip on a given workpiece 214. The finger member 302 may further include an electromagnet to selectively engage the workpiece 214.

[0089] In certain aspects, the end effector 210 may be interchangeable. Thus, a quick connect device may be provided at the distal end of the arm frame 206 to physically and communicatively engage a corresponding quick connect device located on the base 314 of the end effector 210. Thus, the quick connect device may provide two mating parts, a master side and a tool side, which are designed to lock or couple together, carry a payload, and have the ability to transmit utilities such as electrical signals, pneumatics, water, etc. Thus, via the quick connect device, an operator is enabled to quickly exchange and replace the type of end effector 210 installed on the arm frame 206.

[0090] Sensing in the end effector 210 is necessary to provide millimeter-precise positioning and orientation relative to the workpiece 214. Therefore, in order to optimally grasp the workpiece 214, the end effector 210 can provide sensor feedback to the workpiece manipulation system 114 (e.g., the workpiece manipulation processor 402) to adjust the orientation of the lifting mechanism 204. For example, tactile sensing of the end effector 210 combined with distance sensors can assist the workpiece manipulation system 114 and the UAV 100 in orienting the end effector 210 relative to the workpiece 214 and ensuring that the workpiece 214 is securely grasped. Therefore, in addition to the end effector actuator 212 that selectively opens / closes the two finger members 302, the end effector 210 can also include an optical module 304 and other feedback sensors to provide feedback to the UAV 100 regarding the workpiece 214 and the environment adjacent to or near the workpiece 214.

[0091] The optical module 304 may include, for example, a first infrared (IR) camera 306, an RGB (red / green / blue) camera 308, an IR laser projector 310, a second IR camera 312, and the like. The optical module 304 may be positioned proximate to the rear of the end effector 210 (e.g., on a base 314) and configured with a forward field of view to capture images of the workpiece 214 and the environment. The optical module 304 may utilize one or more sensing technologies to enable depth perception, 3D imaging, interior mapping, and feature tracking. The first and second IR cameras 306, 312, together with the IR laser projector 310, provide depth information to calculate the spatial relationship between the end effector 210 and the workpiece 214. Thus, the first IR camera 306 and the second IR camera 312 may be spaced apart from each other to capture different views (i.e., angles) of the workpiece 214 and the environment. Using this data, the workpiece manipulation system 114 (via its workpiece manipulation processor 402 ) can measure the 3D position of the workpiece 214 relative to the end effector 210 to a resolution within 1 mm.

[0092] Other feedback sensors may include, for example, pressure transducers, tactile sensors, and the like. Tactile sensing is used to facilitate impedance control of the lifting mechanism 204 and may be implemented using pressure sensors embedded in the cast rubber. For example, one or more pressure sensors may be positioned on the underside surface of the end effector 210 to contact the stable surface 216 when approaching the workpiece 214. For example, a tactile sensor (e.g., a pressure transducer or a strain gauge) may be arranged on one or more finger elements 302, on the front surface of the base of the end effector 210 (where the sensor can sense the contact force on the finger member 302) or on the bottom surface (where the base 314 will contact the ground); or at the member 206. In addition, the motor driving the gear 304 (which may be positioned in the base 314) may be used for tactile feedback through current sensing in the motor circuit. The workpiece manipulation system 114 may utilize information from the optical module 304 to plan a “rough” approach path that quickly moves the end effector 210 and its tactile sensor proximate to the end effector 210 to within a few millimeters of the workpiece 214 .

[0093] The workpiece manipulation system 114 may further utilize a barcode (e.g., located on the workpiece 214) to identify the workpiece 214 via the RGB camera 308. A plurality of fiducial markers (e.g., April tags or AR tags) on the end effector 210 (e.g., the finger member 302) may assist in determining the precise position of the end effector 210. The workpiece manipulation processor 402, via the optical module 304, is configured to track the plurality of fiducial markers.

[0094] Although the end effector 210 is illustrated as a claw-shaped active gripper having two finger-like members 302, other forms of grippers are contemplated to provide the desired gripping force, such as pinching, entrapment, capture, and vacuum suction. Thus, other end effectors may be coupled to the arm frame 206 to engage the workpiece 214. In fact, the end effector 210 may be an active or passive end effector. In fact, the end effector 210 may utilize active actuation ( Figure 3 ), or it may utilize a passive mechanism that self-aligns with a specific workpiece ( Figure 6ato 6d). Additionally, the end effector may utilize active sensing to carefully align the end effector attachments and the workpiece, or the end effector may be truly based on a gripper that does not require extensive alignment or has automatic alignment features. One example of "active actuation" with "passive sensing" utilizes granular media. For example, where the shape of the workpiece 214 is unknown or inconsistent, the end effector 210 may employ a flexible hollow sphere (or partial sphere) filled with granular material that can conform to the shape of the workpiece 214. As the flexible hollow sphere conforms to the shape of the workpiece 214, a vacuum is utilized to remove air from the flexible hollow sphere, causing the granular material to maintain its shape surrounding the workpiece 214. When the end effector 210 is ready to release, air is returned to the flexible hollow sphere, causing the granular material to loosen and the flexible hollow sphere to resume its original shape. One example of a passive sensing universal gripper comprising a mass of granular material enclosed in an elastic membrane is described in U.S. Patent No. 8,882,165 issued on November 11, 2011 to Hod Lipson et al. and entitled “Gripping and releasing apparatus and method”.

[0095] Figure 3 An actively actuated gripper is illustrated (fingers 302 are driven by gear motors within base 314), but fingers 302 also exhibit some automatic alignment features so that end effector 210 does not need to be fully aligned with the workpiece before closing its fingers to grasp the target. Note that low inertia and back drivable robot arm designs can assist in automatic alignment. An example of passive actuation and passive sensing is a rigid gripper that automatically aligns with a rigid workpiece of known shape, in Figure 6a For example, if the workpiece is a rigid cube with a flange on the upper side, the gripper can be driven to the workpiece by the UAV 100 - with the interface sliding under the flange and gravity being used to hold the workpiece in place on the gripper.

[0096] Figure 4A diagram illustrating an example integrated architecture 400 for an artifact manipulation system 114 is illustrated. In operation, the UAV 100 is capable of coarse positioning based at least in part on inputs from an indoor positioning system 132 (or ISR payload 126) and from an on-board IMU 124c. Specifically, these inputs are used by the aircraft processor 116 for coarse stabilization. However, the artifact manipulation system 114 provides the aircraft processor 116 with additional inputs of similar type to the UAV 100 feedback laws, but at a finer resolution - in part because the artifact manipulation processor 402 (e.g., a microcontroller) has higher fidelity information from other feedback sensors (such as target position sensing, pressure sensing, and joint position sensing). Therefore, coarse positioning and attitude / velocity inputs can be enhanced by finer scale inputs from the artifact manipulation system 114.

[0097] Integration of the workpiece manipulation system 114 with the UAV 100 may be facilitated by using a workpiece manipulation processor 402 that is designed to communicate with the aircraft processor 116 of the host UAV 100 and control the operation of the workpiece manipulation system 114, including its various actuators (e.g., the first joint actuator 208a, the second joint actuator 208b, and the end effector actuator 212). That is, the joint actuators 208a, 208b and the end effector actuator 212 may each include, for example, a motor drive circuit that is controlled by the workpiece manipulation processor 402.

[0098] One or more feedback sensors 406 are configured to monitor the force and position of the first joint actuator 208a, the second joint actuator 208b, and the end effector actuator 212. The one or more feedback sensors 406 may also include current sensors to monitor the current flowing to various actuators to determine the load. The output signal from the one or more feedback sensors 406 may be encoded by an encoder 408 and provided as feedback to a workpiece manipulation processor 402 for a motor control loop 404, etc. The encoder 408 may be attached to a rotating object (e.g., a motor or a joint) to measure rotation, which enables the workpiece manipulation processor 402 to determine the displacement, velocity, acceleration, or angle at the rotation sensor. In fact, the encoder 408 (one or more) may be mounted to the actuator, or to the joint itself.

[0099] The workpiece manipulation processor 402 may also receive feedback from other feedback sensors (e.g., one or more end-point pressure sensors 410) and the optical module 304, which provide target position sensing data. Thus, the workpiece manipulation system 114 is able to provide: (1) tight inner-loop control for arm impedance control; (2) low-level feedback to the UAV 100 inner loops (attitude and velocity) to improve the accuracy of the UAV 100 hovering; and (3) high-level instructions to the aircraft processor 116 to instruct the UAV 100 to approach the workpiece 214. The integrated architecture 400 enables high-bandwidth end-point control of pick and place operations, where the UAV 100 is treated as an element of the entire pick and place system.

[0100] A second IMU 412 may be provided to provide an additional 6-axis gyro and accelerometer combination to the workpiece manipulation system 114 to enhance and compensate for any potential shortcomings in the avionics technology, indoor positioning system 132, and navigation system 124 of the UAV 100. Thus, the workpiece manipulation processor 402 may also receive data from a redundant second IMU 412. The second IMU 412 may be located, for example, on the end effector 210.

[0101] Figures 5a to 5c Example operation of the UAV 100 as it moves toward and grasps the workpiece 214 is illustrated. Figure 5a The UAV 100 is illustrated with the workpiece manipulation system 114 being lowered from its stowed position to a deployed position, wherein the endpoint (e.g., end effector 210) contacts a stable surface 216 at a landing point. As shown, the landing point is adjacent to the workpiece 214. When approaching the target position, the UAV 100 does not require precise positioning because the arm frame 206 is lowered until the end effector 210 contacts a solid stable surface 216 near the target workpiece 214. Tactile sensors at the bottom of the end effector 210 provide closed-loop feedback to the UAV 100 to keep it vertically stable. The optical module 304 identifies the location of the workpiece 214 and any obstacles associated with the UAV 100.

[0102] The UAV 100 slides the end effector 210 using the stabilizing surface 216 as it moves toward the workpiece 214 (identified by direction A) to perform a millimeter-precision pick-up operation. The UAV 100 moves toward the workpiece 214 until the workpiece 214 is within the encirclement of the end effector 210. Although the stabilizing surface 216 is illustrated as being large and the initial landing point is relatively far from the workpiece 214, the end point can be configured to land within a short distance (e.g., 2-10 cm, or directly above) of the workpiece 214 using visual positioning and AR tags, etc. In this example, the UAV 100 orients itself using a horizontal stabilizing surface 216, but any stabilizing surface 216 in any orientation can be utilized, such as a vertical wall near the workpiece 214. The workpiece 214 itself can also be used as a stabilizing surface 216 if it is properly constrained.

[0103] like Figure 5b In the example shown in FIG. 1 , after the workpiece 214 is within the encirclement of the end effector 210, the end effector actuator 212 causes the finger members 302 to close around the workpiece 214. Tactile sensors on the end effector 210 (e.g., the finger members 302) provide feedback to the workpiece manipulation processor 402 to ensure that a secure grip is established with the workpiece 214. The contact between the end effector 210 (via the lifting mechanism 204) and the stable surface 216 will help the UAV 100 to maintain flight stability when it captures the workpiece 214 and prepares to fly away. Figure 5c In the example, UAV 100 stows lift mechanism 204 and workpiece 214 into a transport position, adjusting the arms relative to the system's center of gravity to provide the most efficient flight dynamics. Lift mechanism 204 can also be used to stabilize workpiece 214 during flight.

[0104] Although the lifting mechanism 204 and the end effector 210 described above use active components (e.g., motors, actuators, etc.), in some aspects, a passive lifting mechanism 600 and a passive end effector 610 may be used. Certain aerospace control systems use non-compliant robotic limbs with high rotational inertia; however, these systems do not provide decoupling between the UAV 100 and the contact impact dynamics between the lifting mechanism and the environment (e.g., a stable surface 216, a flat surface, or a hard stop where the workpiece 214 is stored). Instead, these designs can amplify the impact dynamics—which can make existing systems very prone to uncertainty from the perspective of the UAV 100. However, the passive lifting mechanism 600 can be configured to provide directional compliance and directional constraints to minimize the negative effects of impact, provide flexibility between the orientation of the end effector 610 and the orientation of the UAV 100, and utilize reliable constraints in the environment. Passive mechanisms (including passive ankles, etc.) can be adopted in applications where simplicity and cost are required.

[0105] Figure 6a 6d illustrate an example passive lift mechanism 600 that employs a passive end effector 610 that is designed (e.g., sized and shaped) to achieve reliable gripping of a particular workpiece 214. Because no actuation is required, the interfacing geometry between the end effector 610 (exemplified as a passive gripper) and the workpiece 214 should be more precise than that of an actuated end effector 210 ( Figure 3 ) is more controlled. As with the lift mechanism 204, the passive lift mechanism 600 may be mounted to the COTS UAV 100 to enable reliable grasping of the workpiece 214 - ie, aerial manipulation.

[0106] Aeromanipulation achieved by a robotic limb with a highly geared RC servo motor may exhibit high rotational inertia and high friction; and low or zero back-drivability. However, the passive lift mechanism 600 demonstrates that a robotic limb with low friction, low inertia, and sufficient compliance (i.e., stiffness) may enhance the aeromanipulation capabilities of the UAV 100. This enhanced performance results from the ability of the robotic arm to partially decouple the contact interaction dynamics between the end effector 610 and the environment and the flight dynamics of the end effector 610 and the UAV 100.

[0107] Thus, the passive end effector 610 provides two solutions to the problem: (1) a lightweight end effector 610 with a passive "ankle joint 616" enables the end effector 610 to maintain surface contact with a stable surface 216 (e.g., a flat surface / table) - even when the UAV 100 can move in the pitch degree of freedom; and (2) an articulated limb using passive springs can produce favorable compliance so that the distal end of the passive lift mechanism 600 can maintain contact with the stable surface 216 - even when the UAV 100 can move in pitch, roll, and vertical directions. The passive end effector 610 shows that the favorable compliance produced by the passively controlled limb damps out the vibrations caused by the stable surface 216, allowing operation at a precise height near the stable surface 216.

[0108] As shown, the passive lift mechanism 600 may include a lightweight robotic leg 620 having a passive end effector 610 at its distal end and coupled to the UAV via a base 602. The base 602 may be similar to Figure 2a and 2b The robot leg 620 is secured to the underside of the body 102 of the UAV 100 by means of the mounting structure 202 of the UAV 100. As shown, the robot leg 620 may include a set (e.g., two) of independently articulated legs, each articulated leg generally including an upper link 604 (similar to a femur), a middle link 606 (similar to a tibia), and a lower link 608 (similar to a foot). The structural components of the lightweight robot leg 620 (e.g., the upper link 604, the middle link 606, the lower link 608, etc.) may be configured with multiple holes to allow for different limb geometries and reduce the weight of the structure, but the holes may be omitted.

[0109] As through Figure 6a 6d example, the end effector 610 can be supported by two independent / separate knee and hip joints 614, 616. Each knee joint 614 can be configured with a separate elastic element 618, which can move independently. The two-legged approach provides a wider support basin for the UAV 100, while the independent movement of the two legs also enhances the tolerance of the passive lifting mechanism 600 to the rolling action of the UAV 100. The two-legged approach and the end effector 610 design also allow the UAV 100 to move sideways (side-to-side) while maintaining contact between the end effector 610 and the stable surface 216. This ability is enhanced by the independent movement of the two legs, which enables the end effector 610 to maintain surface contact with the stable surface 216 when the flying vehicle rolls.

[0110] The upper link 604 may be pivotally coupled to the base 602 at its proximal end via a hip (upper) joint 612. The upper link 604 may be pivotally coupled to the proximal end of the middle link 606 at its distal end via a knee (middle) joint 614. The middle link 606 may be pivotally coupled to the proximal end of the lower link 608 at its distal end via an ankle (lower) joint 616. The lower link 608 may be coupled (fixedly or pivotally, as desired) to a passive end effector 610 at its distal end. Although the lower link 608 and the end effector 610 are generally described as separate components, they may instead be formed as one (single) component, as may be the case where a fixed connection between the lower link 608 and the end effector 610 is desired. Thus, one or more of the hip joint 612, the knee joint 614, and the ankle joint 616 may employ a pivot joint (e.g., rotation about axis B, C, and / or D). The pivot joint can be formed as a hinge with a pin, a clevis with a pin or the like.

[0111] One or more linear elastic elements 618 (e.g., metal springs, elastic / rubber bands / bands, etc.) may be disposed between the middle link 606 and the rigid body of the base 602 (or upper link 604). In some aspects, the rotating ankle joint 616 of the end effector 610 may be designed so that gravity passively aligns the bottom of the end effector 610 with the stable surface 216. In some aspects, the passive lifting mechanism 600 may be configured with built-in compliance to enable the UAV 100 to fly toward the stable surface 216. The compliance of the legs allows a certain degree of decoupling of the impact between the end effector 610 and the stable surface 216, and the range of motion of the legs and ankles allows contact to be maintained - even if the UAV 100 is not precisely at a vertical height or orientation. This compliance contributes to the stability of the UAV 100. For verification purposes, experiments using the passive lifting mechanism 600 were conducted without joint motion / compliance. Specifically, the revolute joints are made rigid by tightening screws that serve as bearing surfaces. Although some aerodynamic maneuvers are still possible, UAV 100 control is impaired and collisions are more common.

[0112] Control of the UAV 100 approaching the desired workpiece 214 is simplified because it is easier to maintain contact between the end effector 610 and the stable surface 216. In fact, the fully passive lift mechanism 600 can achieve maneuvering when the end effector 610 and the workpiece 214 are designed to match, such as in Figure 6a and 6b214. Specifically, the size and shape of the end effector 610 is set to the dimensions of the workpiece 214. Note that the end effector 610 includes a funnel feature 610a at the front to guide the workpiece 214 into the end effector 610, and the workpiece 214 includes a flange 214a on its upper surface. The funnel feature 610a and the flange 214a allow the end effector 610 and the workpiece 214 to be aligned with each other when the end effector 610 is driven into the workpiece 214. Further, the flange 214a of the workpiece 214 engages the end effector 610, thereby allowing the end effector 610 to lift the workpiece 214.

[0113] The passive lift mechanism 600 may be attached to the UAV 100 such that the end effector 610 is approximately aligned with the center of mass of the UAV 100. However, testing has confirmed that it is easier to "pull" (or "drag") the end effector 610 (i.e., place the end effector 610 slightly "behind" the center of mass), and then drive the UAV 100 forward. This can be attributed to the torque that the UAV 100 applies to itself as it moves forward. That is, in order to move forward, the UAV 100 must lean forward. Therefore, proper placement of the end effector 610 will not fight this motion. Therefore, although Figures 5a to 5c A push configuration is illustrated (ie, the end effector 610 is slightly forward of the center of mass), but the placement of the end effector (whether passive end effector 610 or active end effector 210) can be moved back to achieve a drag / pull configuration.

[0114] In operation, the UAV 100 flies in front of the workpiece 214. The UAV 100 is driven forward (toward the workpiece 214) and the end effector 610 is dragged to the junction with the workpiece 214. The compliance of the passive lifting mechanism 600 provides suspension between the UAV 100 and the stable surface 216 when the end effector 610 contacts the stable surface 216. The rotational compliance of the end effector 610 enables flat surface contact between the end effector 610 and the stable surface 216 without requiring flawless alignment by the UAV 100. The hip joint 612 can be fixed, or configured to rotate. The elastic element 618 attached between the knee joint 614 and the hip joint 612 provides compliance of the knee joint 614. The ankle joint 616 rotates freely. The end effector 610 is designed so that gravity pulls it parallel to the stable surface 216. The ankle joint 616 can align with the ground at an angle. The knee joint 614 can be configured to flex significantly upon contact with the stable surface 216. The specific limb geometry can be selected to enable the UAV 100 to move a predetermined vertical distance (e.g., 2 to 12 inches, 2 to 8 inches, or approximately 4 inches) above the stable surface 216 while the end effector 610 maintains contact with the stable surface 216. Once the workpiece 214 is captured (i.e., secured by the end effector 610), the UAV 100 lifts off and flies away.

[0115] In order to provide all-weather operation (e.g., 24 hours a day, 7 days a week), the UAV 100 should be configured to provide continuous operation. However, the problem is that the UAV 100 is limited by its battery capacity. Nevertheless, continuous operation can be facilitated in a variety of ways, including a tag team approach, a battery swapping approach, and / or an overhead tether system.

[0116] In a grouping approach, multiple UAVs 100 may be deployed with one UAV 100 operating while the remaining UAVs 100 are recharging their batteries. It will be appreciated that the number of UAVs 100 required in the grouping approach is a function of the UAV 100 operating time and the time required for the UAV 100 to recharge. For example, if a UAV 100 can operate for 15 minutes before needing to recharge its battery and recharging takes 75 minutes, then six (6) UAVs 100 are required for continuous operation, each with its own charging station. The charging station may be a contact charging station or a contactless charging station (e.g., utilizing one or more inductive charging technologies). The grouping approach provides the advantage of having multiple UAVs 100 available to perform parallel missions simultaneously (under proper schedule management). However, the purchase cost of the entire system will be six times higher than that of a single UAV 100, and operating and maintenance costs will increase. In the battery replacement method, an operator (or a robotic system) can be used to: remove the spent battery pack from the UAV 100; replace it with a new battery pack; and place the spent battery pack in a charger. The battery replacement method provides the advantage of eliminating the need for several UAVs 100, but introduces the time cost of an operator replacing battery packs and the complexity associated with a robotic battery replacement system.

[0117] Overhead tether systems will introduce wire tethers to provide continuous, uninterrupted power to the UAV 100, and eliminate the need for batteries, freeing up valuable lifting capacity and making the UAV 100 significantly smaller. The wire tether will also provide a safer UAV 100 in the event of a fault, because the wire tether can be used to catch the UAV 100 if it deviates from the right track or fails. However, the tether limits the number of UAVs 100 that can be operated in series or in groups, and limits the movement of each UAV 100. In the case where the UAV 100 can operate using sunlight (or other equivalent light), one or more solar panels can be installed on the UAV 100 to extend battery life. Exemplary solar aircraft configurations and techniques are described in commonly owned U.S. patent application Ser. No. 15 / 593,617 (filed May 12, 2017, and entitled “Solar Power System and Method Thereof”) and U.S. patent application Ser. No. 15 / 134,938 (filed April 21, 2016, and entitled “Solar-Powered Aircraft”).

[0118] The patents and patent publications cited above are incorporated herein by reference in their entirety. In the case where the definition of terms or usage in the references incorporated herein by reference is inconsistent or contrary to the definition of terms or understanding provided herein, the meaning of the terms provided herein shall prevail, and the definition of the terms in the references may not necessarily apply. Although various embodiments have been described with reference to the specific arrangement of parts, features and the like, these are not intended to exhaust all possible arrangements or features, and in fact a variety of other embodiments, modifications, and changes will be determinable for those skilled in the art. Therefore, it is to be understood that the teachings of the present disclosure can therefore be practiced in a manner other than the above specific description.

Claims

1. An aerospace workpiece (214) manipulation system, which provides high-precision manipulation of a workpiece (214), the aerospace workpiece (214) manipulation system comprising: Body (102); A plurality of rotor frames (104) extending radially from the body (102); a plurality of propellers, each of the plurality of propellers (108) being positioned distally of one of the plurality of rotor trusses (104) and electrically coupled to an electronic speed controller (ESC) (106) that is controlled by an aircraft processor (116); a lifting mechanism (204) coupled to the body (102), wherein the lifting mechanism (204) includes one or more joint actuators (208, 208a) to extend or retract the lifting mechanism (204) relative to the body (102); an end effector (210, 610) coupled to the lifting mechanism, wherein the end effector (210, 610) includes an end effector (210, 610) actuator to control the operation of the end effector (210, 610) to manipulate the workpiece (214); as well as a second processor communicatively coupled to the aircraft processor (116) and configured to control operation of the end effector (210, 610) actuator and the one or more joint actuators (208, 208a), wherein the workpiece (214) manipulation system is configured to bring the end effector (210, 610) into contact with a stable surface (216) on which the workpiece (214) is located and to move the end effector (210, 610) along the stable surface (216) toward the workpiece (214), and The end effector (210, 610) includes one or more feedback sensors to provide feedback data to the second processor to guide the system to approach the workpiece (214), wherein the feedback sensors include one or more pressure sensors positioned on the underside surface of the end effector (210, 610) to contact the stable surface (216) when approaching the workpiece (214).

2. The aviation workpiece (214) manipulation system of claim 1, wherein the lifting mechanism (204) is a four-bar linkage having four connecting rods (204a, 204b, 204c, 204d) connected in a loop through four connecting joints.

3. An aviation workpiece (214) manipulation system as described in claim 2, wherein the lifting mechanism (204) is coupled to the body (102) at a first connection joint via a mounting structure (202), and wherein the one or more joint actuators (208, 208a) are configured to cause at least one of the four connecting rods (204a, 204b, 204c, 204d) to pivot about a rotation axis of the first connection joint (218a).

4. An aviation workpiece (214) manipulation system as described in claim 3, wherein the one or more joint actuators (208, 208a) include a first joint actuator and a second joint actuator, wherein the first joint actuator is configured to cause one of the four connecting rods (204a, 204b, 204c, 204d) to pivot about the rotation axis of the first connecting joint (218a), and the second joint actuator is configured to cause another one of the four connecting rods (204a, 204b, 204c, 204d) to pivot about the rotation axis of the first connecting joint (218a).

5. The aerospace workpiece (214) manipulation system of any one of claims 1-4, wherein the end effector (210, 610) actuator and the one or more joint actuators (208, 208a) each comprise a brushless DC back-drivable motor.

6. The aerospace workpiece (214) manipulation system of any one of claims 1-4, wherein the end effector (210, 610) includes an optical module communicatively coupled to the second processor.

7. The aerospace workpiece (214) manipulation system of claim 1, wherein the end effector (210, 610) includes a pressure sensor communicatively coupled to the second processor.

8. The aerospace workpiece (214) manipulation system of claim 6, wherein the end effector (210, 610) includes a plurality of fiducial markers to assist in determining the position of the end effector.

9. A workpiece (214) manipulation system for an aircraft to provide high-precision manipulation of a workpiece (214), the workpiece (214) manipulation system comprising: a lifting mechanism (204) coupled to the aircraft, wherein the lifting mechanism (204) includes one or more joint actuators (208, 208a) to extend or retract the lifting mechanism (204) relative to the aircraft; an end effector (210, 610) coupled to the lifting mechanism, wherein the end effector (210, 610) includes an end effector (210, 610) actuator to control the operation of the end effector (210, 610) to manipulate the workpiece (214); as well as a processor communicatively coupled to the aircraft processor (116) and configured to control operation of the end effector (210, 610) actuator and the one or more joint actuators (208, 208a), wherein the workpiece (214) manipulation system is configured to bring the end effector (210, 610) into contact with a stable surface (216) on which the workpiece (214) is located and to move the end effector (210, 610) along the stable surface (216) toward the workpiece (214), and wherein the end effector (210, 610) includes one or more feedback sensors to provide feedback data to the processor communicatively coupled to the aircraft processor (116) to guide the system to approach the workpiece (214), wherein the feedback sensors include one or more pressure sensors positioned on an underside surface of the end effector (210, 610) to contact the stable surface (216) when approaching the workpiece (214).

10. The workpiece (214) manipulation system of claim 9, wherein the lifting mechanism (204) is a four-bar linkage having four connecting rods (204a, 204b, 204c, 204d) connected in a loop through four connecting joints.

11. The workpiece (214) handling system of claim 9 or 10, wherein the lifting mechanism (204) is configured to be removably coupled to the aircraft via a mounting structure (202).

12. The workpiece (214) manipulation system of claim 9 or 10, wherein the end effector (210, 610) includes an optical module communicatively coupled to the processor.

13. The workpiece (214) manipulation system of claim 9 or 10, wherein the end effector (210, 610) includes a pressure sensor communicatively coupled to the processor.

14. The workpiece (214) manipulation system of claim 9 or 10, wherein the end effector (210, 610) is detachably coupled to the lifting mechanism (204) so ​​that the end effector (210, 610) can be exchanged with another end effector.

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