Parrot

Parrot Drones

Parrott

Francois Callou

Michael Rischmuller

Gilles Foinet

Henri Seydoux

Pierre Eline

Laure Chevalley

Mathieu Babel

Etienne Caldichoury

A vertical-view camera () delivers an image signal (S) of the ground overflown by the drone. Gyrometric sensors () measure the Euler angles (&#x3c6;, &#x3b8;, &#x3a8;) characterizing the attitude of the drone and delivering a gyrometric signal (S) representative of the instantaneous rotations. Rotation compensation means () receive the image signal and the gyrometric signal and deliver retimed image data, compensated for the rotations, then used to estimate the horizontal speeds of the drone. The camera and the inertial unit are piloted by a common clock (), and it is provided a circuit () for determining the value of the phase-shift between the gyrometric signal and the image signal, and to apply this phase-shift value at the input of the rotation compensation means () to resynchronize the image signal onto the gyrometric signal before computation of the retimed image data.

Drone provided with a vertical-view video camera compensated for the instantaneous rotations for estimation of the horizontal speeds

The drone () comprises an onboard video camera () picking up a sequence of images to be transmitted to a remote control. The user selects an exposure mode such as forward or sideways, panoramic or boom plane, tracking, defining a trajectory to be transmitted to the drone. Corresponding setpoint values are generated and applied to a processing subsystem controlling the motors of the drone. Once the drone is stabilized on the prescribed trajectory (), the exposure by the video camera () is activated and the trajectory is stabilized by an open loop control avoiding the oscillations inherent in a servocontrol with feedback loop.

Method for piloting a rotary wing drone for taking an exposure through an onboard camera with minimization of the disturbing movements

The attitude and speed of the drone are controlled by angular commands applied to a control loop () for controlling the engines of the drone according to the pitch and roll axes. A dynamic model of the drone, including, in particular, a Kalman predictive filter, represents the horizontal speed components of the drone on the basis of the drone mass and drag coefficients, the Euler angles of the drone relative to an absolute terrestrial reference, and the rotation of same about a vertical axis. The acceleration of the drone along the three axes and the relative speed of same in relation to the ground are measured and applied to the model as to estimate () the horizontal speed components of the cross wind. This estimation can be used to generate corrective commands () that are combined with the angular commands applied to the control loop of the drone in terms of pitch and roll.

Method for controlling a multi-rotor rotary-wing drone, with cross wind and accelerometer bias estimation and compensation

The drone comprises: a vertical-view camera () pointing downward to pick up images of a scene of the ground overflown by the drone; gyrometer, magnetometer and accelerometer sensors (); and an altimeter (). Navigation means determine position coordinates (X, Y, Z) of the drone in an absolute coordinate system linked to the ground. These means are autonomous, operating without reception of external signals. They include image analysis means, adapted to derive a position signal from an analysis of known predetermined patterns (), present in the scene picked up by the camera, and they implement a predictive-filter estimator () incorporating a representation of a dynamic model of the drone, with as an input the position signal, a horizontal speed signal, linear and rotational acceleration signals, and an altitude signal.

Rotary-wing drone comprising autonomous means for determining a position in an absolute coordinate system linked to the ground

The drone comprises altitude determination means (), with an estimator () combining the measures of an ultrasound telemetry sensor () and of a barometric sensor () to deliver an absolute altitude value of the drone in a terrestrial system. The estimator comprises a predictive filter () incorporating a representation of a dynamic model of the drone making it possible to predict the altitude based on the motor commands () and to periodically readjust this prediction as a function of the signals delivered by the telemetry sensor () and the barometric sensor (). Validation means analyze the reflected echoes and possibly modify the parameters of the estimator and/or allow or invalidate the signals of the telemetry sensor. The echo analysis also makes it possible to deduce the presence and the configuration of an obstacle within the operating range of the telemetry sensor, to apply if need be a suitable corrective action.

Altitude estimator for a rotary-wing drone with multiple rotors

This method controls the drone in order to flip through a complete turn about its roll axis or its pitching axis. It comprises the steps of: a) controlling its motors simultaneously so as to impart a prior upward vertical thrust impulse to the drone; b) applying different and non-servo-controlled commands to the motors so as to produce rotation of the drone about the axis of rotation of the flip, from an initial angular position to a predetermined intermediate angular position; and then c) applying individual control to the motors, servo-controlled to a reference target trajectory, so as to finish off the rotation of the drone through one complete turn about the axis of rotation, progressively from the intermediate angular position with a non-zero angular velocity to a final angular position with a zero angular velocity.

Method of dynamically controlling the attitude of a drone in order to execute a flip type maneuver automatically

The user inclines the apparatus () according to the pitch () and roll () axes to produce inclination signals (&#x3b8;, &#x3c6;) which are transformed into corresponding command setpoints (&#x3b8;, &#x3c6;) for the drone () in terms of attitude of the drone according to the pitch () and roll () axes of the drone. The drone and the apparatus each determine the orientation of their local reference frame (XYZ; XYZ) in relation to an absolute reference frame linked to the ground (XYZ), to determine the relative angular orientation of the drone in relation to the apparatus. Then, the reference frame of the apparatus is realigned on the reference frame of the drone by a rotation that is a function of this relative angular orientation. The realigned values thus correspond to user commands referenced in the reference frame of the apparatus and no longer in that of the drone, which allows for more intuitive piloting when the user is watching the drone.

Method for the intuitive piloting of a drone by means of a remote control

This method implements a transition from i) moving state in which the drone is flying at speed and tilt angle that are not zero to ii) hovering state in which the drone has speed and tilt angle that are both zero. The method comprises: a) measuring horizontal linear speed, tilt angles, and angular speeds at the initial instant; b) setting stopping time value; c) on the basis of initial measurements and set stopping time, parameterizing a predetermined predictive function that models optimum continuous decreasing variation of horizontal linear speed as a function of time; d) applying setpoint values to a loop for controlling motors of the drone, which values correspond to target horizontal linear speed precalculated from said parameterized predictive function; and e) once hovering state has been reached, activating a hovering flight control loop for maintaining drone at speed and tilt angle that are zero relative to the ground.

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Paris, France

Francois Callou