Robust and autonomous docking and recharging of quadrotors

• US 9,573,701 B2
• Filed: 08/06/2014
• Issued: 02/21/2017
• 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: Eriksson, Michael, Rehder, Joern, Beardsley, Paul A., Alonso-Mora, Javier
• Primary Examiner(s): Badii, Behrang
• Assistant Examiner(s): Malhotra, Sanjeev
• Application Number:
  US14/452,819
• Publication Number:
  US 20160039541A1
• Time in Patent Office: 930 Days
• Field of Search: 701/2, 701/3, 701/23, 738/49, 403/119, 439/66, 244/114.R
• 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: 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

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,

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,

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.

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 1, 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.

4. The system of claim 3, 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.

5. 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 an asymmetric pattern, and wherein the docking station comprises a controller processing frames captured by the camera to identify the station-mating frame based on the asymmetric pattern of the light sources, and, in response, to communicate landing control signals to the UAV.

6. The system of claim 5, 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.

7. The system of claim 5, 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.

8. The system of claim 7, 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.

9. The system of claim 8, 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.