ROBUST AND AUTONOMOUS DOCKING AND RECHARGING OF QUADROTORS

• US 20160039541A1
• Filed: 08/06/2014
• Published: 02/11/2016
• Est. Priority Date: 08/06/2014
• Status: Active Grant

• Current Assignee: ETH Zurich, Disney Enterprises Incorporated (The Walt Disney Company)
• Original Assignee: Disney Enterprises Incorporated (The Walt Disney Company)
• Inventors: BEARDSLEY, PAUL A., ALONSO-MORA, JAVIER, ERIKSSON, MICHAEL, REHDER, JOERN
• Granted Patent: US 9,573,701 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B60L 2200/10 Air crafts
• CPC Class Codes: B60L 53/14 Conductive energy transfer
• CPC Class Codes: B60L 53/30 Constructional details of charging stations
• CPC Class Codes: B60L 53/36 by positioning the vehicle
• CPC Class Codes: B60L 53/37 using optical position determination, e.g. using cameras
• CPC Class Codes: B64C 39/024 of the remote controlled vehicle type, i.e. RPV
• CPC Class Codes: B64F 1/362 Installations for supplying conditioned air to parked aircraft
• CPC Class Codes: B64U 10/10 Rotorcrafts
• CPC Class Codes: B64U 10/14 with four distinct rotor axes, e.g. quadcopters
• CPC Class Codes: B64U 2201/10 autonomous, i.e. by navigating independently from ground or air stations, e.g. by using inertial navigation systems [INS]
• CPC Class Codes: B64U 2201/20 Remote controls
• CPC Class Codes: B64U 30/20 Rotors; Rotor supports
• CPC Class Codes: B64U 50/19 using electrically powered motors
• CPC Class Codes: B64U 50/34 In-flight charging photovoltaics B64U50/31
• CPC Class Codes: B64U 70/30 for capturing UAVs in flight by ground or sea-based arresting gear, e.g. by a cable or a net
• CPC Class Codes: B64U 70/95 Means for guiding the landing UAV towards the platform, e.g. lighting means
• CPC Class Codes: G05D 1/0011 associated with a remote control arrangement
• CPC Class Codes: G05D 1/0088 characterized by the autonomous decision making process, e.g. artificial intelligence, predefined behaviours using knowledge based models G06N5/00
• CPC Class Codes: G05D 1/042 specially adapted for aircraft
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/7072 : Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
• CPC Class Codes: Y02T 90/12 : Electric charging stations
• CPC Class Codes: Y02T 90/14 : Plug-in electric vehicles

Abstract

A method of docking and recharging using a base station and a station-mating frame on the multicopter. The base station includes an upward-facing camera that is used by a docking controller to detect the presence, position, and orientation of a frame, with infrared light-emitting diodes arranged in a predefined pattern. The controller of the base station acts to emit wireless signals to the multicopter to guide the multicopter with its station-mating frame to a predefined position above the base station. The controller transmits a wireless signal to the multicopter to reduce thrust, and the multicopter lowers itself onto a sloped receiving surface that may be arranged in a crown pattern to provide passive gravity-driven centering, which causes the station-mating frame to slide to a lowest vertical point of the receiving assembly. A locking mechanism engages to lock the frame in place and provide electrical contact for recharging.

Claims

11. A control method for docking and charging a multicopter, comprising:

detecting a presence of a frame on the multicopter in an airspace above receiving surfaces of base station;

determining a first position of the frame relative to the receiving surfaces;

transmitting a first control signal to the multicopter to move from the first position to a second position over the receiving surfaces;

determining the multicopter is in the second position;

after the multicomputer is determined to be in the second position, transmitting a second control signal to the multicopter to turn off thrust;

receiving the multicopter with the receiving surfaces and passively guiding the frame into a set of receiving grooves; and

charging a battery via electrical connection of contacts on the frame and contacts on the base station.

1. A system for autonomous docking and charging of an unmanned aerial vehicle (UAV), comprising:

a docking station including a vertical sidewall extending about a perimeter of an open space and having a plurality of sloped receiving surfaces arranged in a pattern of alternating peaks and valleys; and

a station-mating frame affixed to the UAV comprising a first linear arm and a second linear arm, wherein the first and second linear arms are coplanar and orthogonal and wherein the first and second linear arms each have a length greater than an outer dimension of the perimeter of the open space defined by the vertical sidewall.

2. The system of claim 1, wherein the sloped receiving surfaces are each provided at a slope angle of at least 15 degrees, whereby the UAV with the station-mating frame slides under gravity into the valleys when the first and second linear arms contact the sloped receiving surfaces.

3. The system of claim 2, wherein a charging contact is provided on at least one of the first and second linear arms and wherein a charging contact, linked to an electrical power supply, is provided in at least one of the valleys of the sloped receiving surfaces, whereby the charging contacts have an electrical connection when the first and second linear arms are received in the valleys of the sloped receiving surfaces.

4. The system of claim 3, further comprising a locking mechanism in the docking station adapted for retaining the first and second linear arms in the valleys of the sloped receiving surfaces and for urging the charging contact on the at least one of the first and second linear arms into contact with the charging contact in the at least one of the valleys of the sloped receiving surfaces.

5. The system of claim 4, wherein recessed grooves are provided at lowest points in the valleys for receiving the first and second linear arms, wherein the locking mechanism is actuable to retain the first and second linear arms within the recessed grooves, and wherein the charging contact in the at least one of the valleys of the sloped receiving surfaces is provided in the recessed grooves.

6. The system of claim 1, wherein the docking station comprises a camera facing upward from the open space enclosed by the vertical sidewalls, wherein the station-mating frame comprises a plurality of light sources arranged on the first and second linear arms in a pattern, and wherein the docking station comprises a controller processing frames captured by the camera to identify the station-mating frame based on the pattern of the light sources, and, in response, to communicate landing control signals to the UAV.

7. The system of claim 6, wherein the plurality of light sources are mounted in spaced apart and crossing lines on the first and second linear arms to allow the controller to process the frames with projective invariance.

8. The system of claim 6, wherein the plurality of light sources each comprises infrared (IR) light emitting diodes (LEDs) and the camera includes an IR filter filtering out ambient light.

9. The system of claim 8, wherein the landing control signals include a pose of the UAV determined based on an orientation of the asymmetric pattern in the captured frames and include a signal to reduce thrust when the UAV is tracked to a pre-landing position above the sloped receiving surfaces of the vertical walls.

10. The system of claim 9, wherein the UAV comprises a quadrotor and wherein the reduced thrust signal comprises instructions to reduce speed of motors on the quadrotor to allow the quadrotor to land or lower onto the receiving surfaces.

12. The method of claim 11, wherein the processing of the image comprises applying a Kalman Filter in searching for the predefined pattern in the image.

13. The method of claim 11, wherein the frame comprises orthogonally crossed linear arms and a plurality of light sources positioned on the arms in a predefined pattern and wherein the detecting of the presence of the frame comprises processing an image captured by a camera for light points in the predefined pattern.

14. The method of claim 13, wherein the light sources comprise a number of IR LEDs.

15. The method of claim 14, wherein the processing of the image captured by the camera comprises masking out non-infrared radiation.

16. The method of claim 12, wherein the method further comprises determining a pose of the multicopter based on the light points and the predefined pattern and wherein the first control signal is generated based on the determined pose of the multicopter.

17. The method of claim 11, further comprising, after the receiving, sensing a portion of the frame within a receiving groove in the receiving surfaces and, in response, activating a locking mechanism to retain the frame within the receiving groove and to urge the frame into a charging position to provide the electrical connection or improve an efficiency of the charging with the electrical connection.

18. A base station for use with a quadrotor carrying a frame formed with two linear and crossed arms, comprising:

a camera;

a sidewall extending about and enclosing a space including the monochromatic camera, wherein the monochromatic camera is facing upward from the enclosed space and captures digital images of light directed downward into the enclosed space; and

a controller with a processor executing code on computer readable media to cause the controller to;

(a) process the digital images to identify a predefined pattern of light points, wherein a plurality of LEDs are positioned in the predefined pattern on the two linear and crossed arms of the frame;

(b) to determine a position of the frame relative to the base station; and

(c) to communicate position or pose data to the quadrotor to land on the base station with the quadrotor frame making contact with upper edges of the sidewall.

19. The base station of claim 17, wherein the upper edges of the sidewall are arranged in an alternating peak and valley pattern, whereby the upper edges each have a slope causing the frame of the quadrotor, when received on the upper edges, to slide under gravity into lowest vertical positions on the sidewall.

20. The base station of claim 19, further comprising at least one charging contact connected to a power supply for mating with a contact on the frame of the quadrotor and a locking mechanism operable by the controller upon receipt of the frame in the lowest vertical positions on the sidewall to retain the frame on the vertical sidewalls and to urge the at least charging contact to engage the contact on the frame.

18-1. The base station of claim 17, wherein the LEDs are IR LEDs and wherein the processing of the digital images comprises masking non-infrared radiation from the digital images.

21. A system for landing a UAV, comprising:

a landing dock with a controller and a wireless communication assembly;

a target assembly on the UAV; and

in the landing dock, a sensor assembly sensing the target assembly and output sensor signals to the controller,

wherein the controller processes the output sensor signals to determine a position of the UAV relative to the landing dock, and

wherein the controller transmits, using the wireless communication assembly, control signals to the UAV to guide the UAV to land on the landing dock based on the determined relative position of the UAV.