US 9,415,870 B1Granted

Unmanned aerial vehicle motor driving randomization and feedback for noise abatement

AssigneeAmazon Technologies, Inc.

InventorsBrian C. Beckman, Fabian Hensel, Atishkumar Kalyan, Gur Kimchi

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Abstract

This disclosure is directed to monitoring a noise signature of an unmanned aerial vehicle (UAV) and varying the speed of the motors of the UAV to reduce unwanted sound (i.e., noise) of the UAV based on the noise signature. The noise signature of the UAV may be measured by an audio sensor of a vibration sensor, and feedback may be provided to the UAV. The UAV may generate noise during flight, which may include a number of noise components such as tonal noise (e.g., a whining noise such as a whistle of a kettle at full boil) and broadband noise (e.g., a complex mixture of sounds of different frequencies, such as the sound of ocean surf). By measuring the noise signature of the UAV, and varying the motor revolutions per minute (RPM) during flight operations, the UAV may reduce tonal components of the UAV noise signature.

Claims20

Dependent claims

An unmanned aerial vehicle (UAV) configured to deliver a package, the UAV comprising:

a frame;
a plurality of motors including at least a first motor and a second motor, each motor coupled to the frame and configured to rotate at least one propeller to cause lift and propulsion for the UAV;
a power source to selectively provide power to the plurality of motors;
an audio sensor to measure a tonal component of sound generated by propellers of the UAV;
a control system in communication with at least the plurality of motors and the power source, the control system to control at least operation of the plurality of motors, the control system to perform operations comprising:
determining a flight control of the UAV, the flight control of the UAV including at least a heading and a velocity of the UAV;
determining a first motor speed of the first motor of the UAV, wherein the first motor speed is based in part on the flight control of the UAV;
determining a second motor speed of at least the second motor of the UAV, wherein the second motor speed is based in part on the flight control of the UAV;
a closed-loop noise controller configured to perform operations comprising:
determining that the UAV is operating in a noise-sensitive location;
receiving a first audio signal from the audio sensor at a first time indicating a first tonal component of the sound generated by the propellers of the UAV;
calculating a first randomization motor speed by applying a first random value within a randomization threshold to the first motor speed;
sending the first randomization motor speed to the control system to control operation of at least the first motor;
receiving a second audio signal from the audio sensor at a second time indicating a second tonal component of the sound generated by the propellers operating using the first randomization motor speed;
determining that a second amplitude of the second tonal component is greater than a first amplitude of the first tonal component;
calculating a second randomization motor speed by applying a second random value within the randomization threshold to the first motor speed;
and
sending the second randomization motor speed to the control system to control operation of at least the first motor.

15 more elements

An unmanned aerial vehicle (UAV) comprising:

one or more processors;
memory coupled to the one or more processors, the memory including one or more modules that are executable by the one or more processors to perform operations comprising:
determining a flight control of the UAV, the flight control of the UAV including at least a heading and a velocity of the UAV;
receiving, from one or more sensors coupled to the UAV, first sensor feedback at a first time indicating a first tonal component of a first noise signature of the UAV;
determining a first motor speed of the first motor of the UAV, wherein the first motor speed is based in part on the flight control of the UAV;
changing the first motor speed to a first adjusted motor speed by randomly selecting the first adjusted motor speed within a randomization threshold;
receiving, from the one or more sensors coupled to the UAV, second sensor feedback at a second time indicating a second tonal component of a second noise signature of the UAV;
comparing a second amplitude of the second tonal component of the second noise signature to a first amplitude of the first tonal component of the first noise signature;
determining that the second amplitude of the second tonal component of the second noise signature is greater than the first amplitude of the first tonal component of the first noise signature;
and
changing the first adjusted motor speed to a second adjusted motor speed by randomly selecting the second adjusted motor speed within the randomization threshold.

8 more elements

Dependencies are inferred from the claim text.