SYSTEMS AND METHODS FOR DYNAMICS, MODELING, SIMULATION AND CONTROL OF MID-FLIGHT COUPLING OF QUADROTORS

• US 20180164835A1
• Filed: 09/26/2017
• Published: 06/14/2018
• Est. Priority Date: 09/27/2016
• Status: Active Grant

• Current Assignee: Arizona Board of Regents (University of Arizona)
• Original Assignee: Arizona Board of Regents (University of Arizona)
• Inventors: Artemiadis, Panagiotis, Larsson, Daniel
• Granted Patent: US 10,642,285 B2
• Time in Patent Office: Days
• CPC Class Codes: B64U 10/13 Flying platforms
• 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 30/20 Rotors; Rotor supports
• CPC Class Codes: G05D 1/08 Control of attitude, i.e. control of roll, pitch, or yaw
• CPC Class Codes: G05D 1/0858 specially adapted for vertical take-off of aircraft
• CPC Class Codes: G05D 1/10 Simultaneous control of position or course in three dimensions G05D1/12 takes precedence
• CPC Class Codes: G05D 1/104 involving a plurality of aircrafts, e.g. formation flying traffic control systems for aircraft G08G5/00

Abstract

A first rotorcraft is provided, including a plurality of first coupling points. A second rotorcraft is provided, including a plurality of second coupling points. The first rotorcraft is mechanically coupled to the second rotorcraft using the plurality of first coupling points and the plurality of second coupling points to form a coupled configuration. A joint controller is implemented to maneuver the first rotorcraft and the second rotorcraft of the coupled configuration. Gains associated with the joint controller are set dependent on the application and anticipated maneuvers. The gains are scheduled to be moderate at time instances immediately following the formation of the coupled configuration and then the gains are changed to more aggressive values once the coupled configuration has been stabilized.

Claims

1. A system for controlling a plurality of rotorcrafts, comprising:

a first controller implemented by a processor;

a first rotorcraft in operative communication with the first controller, the first rotorcraft including a plurality of first coupling points;

a second rotorcraft, the second rotorcraft comprising a plurality of second coupling points, the second coupling points configured to temporarily engage with the first coupling points; and

a joint controller implemented by the processor for navigating the first rotorcraft and the second rotorcraft;

wherein the first rotorcraft is operable to assume a coupled configuration with the second rotorcraft by utilizing the first controller to modify an altitude and coordinates associated with yaw, pitch and roll angles of the first quadrotor relative to the second rotorcraft and adjoin the first coupling points with the second coupling points; and

wherein in the coupled configuration, gains of the joint controller are scheduled such that the gains are set to a first setting immediately following the assumption of the coupled configuration and the gains are subsequently modified to a second setting.

2. The system of claim 1, wherein the gains of the second setting are greater than the gains of the first setting, and changes to the gains define a gain scheduling to accommodate stabilization of the first rotorcraft and the second rotorcraft while assuming the coupled configuration.

3. The system of claim 1, wherein the processor is mounted to a portion of the first rotorcraft such that the first controller defines an onboard controller.

4. The system of claim 1, wherein the first controller is implemented to:

construct a first control loop to compute a force for adjusting translational acceleration and positioning of the first rotorcraft along an inertial Z-axis at a predetermined location proximate the second rotorcraft, and

construct a second control loop for determining a plurality of moments for adjusting angles associated with yaw, pitch and roll of the first rotorcraft to orient the first rotorcraft in a predetermined position over the second rotorcraft; and

wherein the force and plurality of moments are utilized to configure an angular velocity of each of a plurality of motors associated with the first rotorcraft.

5. The system of claim 1, wherein upon assuming the coupled configuration between the first rotorcraft and the second rotorcraft, the joint controller assumes responsibility for a position and a velocity of the first rotorcraft and the second rotorcraft in the coupled configuration.

6. The system of claim 5, wherein derivative control values on position are set to a first value greater than a set of proportional gain values in order to provide adequate dampening to the system.

7. The system of claim 6, wherein upon motion of the first rotorcraft and the second rotorcraft in the coupled configuration being initiated towards an intended target, the proportional gain values and derivative control values are increased to provide a faster response time.

8. The system of claim 1, wherein the plurality of first coupling points and the plurality of second coupling points comprise magnets.

9. The system of claim 1, wherein the plurality of first coupling points and the plurality of second coupling points comprise a plurality of respective ball and socket joints.

10. A method, comprising:

providing a first rotorcraft, the first rotorcraft including a plurality of first coupling points and a first controller for navigating the first rotorcraft;

providing a second rotorcraft, the second rotorcraft including a plurality of second coupling points;

navigating the first rotorcraft over the second rotorcraft such that the plurality of first coupling points align with the plurality of second coupling points;

mechanically coupling the first rotorcraft to the second rotorcraft to form a coupled configuration by engaging the plurality of first coupling points with the plurality of second coupling points;

providing a joint controller for navigating the coupled configuration including the first rotorcraft and the second rotorcraft; and

tuning gain values associated with the joint controller to accommodate for the coupled configuration.

11. The method of claim 10, wherein the second rotorcraft is in a stationary position relative to the first rotorcraft.

12. The method of claim 10, wherein the second rotorcraft is in motion such that the navigating of the first rotorcraft over the second rotorcraft defines an intercept of the second rotorcraft by the first rotorcraft.

13. The method of claim 10, further comprising setting desired locations and velocities associated with the joint controller as those of the first rotorcraft.

14. The method of claim 10, further comprising adjusting for a linkage offset of the coupled configuration to safely land the coupled configuration.

15. The method of claim 10, wherein the gain values are variable and change throughout a flight of the coupled configuration.

16. An apparatus, comprising:

a first rotorcraft, the first rotorcraft including a motor and a coupling mechanism for mechanically with a second rotorcraft; and

a processor in operative communication with the first rotorcraft, the processor implementing a plurality of controllers, each of the plurality of controllers operative to command a rotational frequency of the motor of the first rotorcraft, the plurality of controllers including a joint controller with gains associated with the joint controller being variable to accommodate coupling of the first rotorcraft to the second rotorcraft.

17. The apparatus of claim 16, wherein the first rotorcraft comprises a quadrotor, and the coupling mechanism comprises a plurality of magnets positioned along a vertical surface of the first rotorcraft.

18. The apparatus of claim 16, wherein each of the plurality of magnets is recessed to increase friction between the first rotorcraft and the second rotorcraft.

19. The apparatus of claim 16, further comprising a sensor for determining an orientation, a position and a velocity of the first rotorcraft, the sensor in operative communication with the plurality of controllers.

20. The apparatus of claim 16, wherein the joint controller comprises a proportional integral derivative controller to control a location and a velocity of the first rotorcraft upon being coupled to the second rotorcraft.