IP Library › Granted Patent US 12698088

Granted Patent B1

US 12698088 · App. 18/621,657 · Granted Aug 4, 2026

Fault detection systems and methods for electric drives using redundant speed and position data

Inventors: Lizon Maharjan (Seattle, WA); Xiaoqi Wang (Bellevue, WA); Tausif Husain (Maple Valley, WA); Sheverria Antony Aikens (Mill Creek, WA); Frederic Pierre Lacaux (Kirkland, WA)

Assignee: Amazon Technologies, Inc.

B64D31/09 B64F5/60 G01P3/48

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Quick Facts

Patent No.: US 12698088
App. No.: 18/621,657
Granted: Aug 4, 2026
Kind: B1

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Abstract

Fault detection systems and methods may include error determinations related to position sensors and/or sensorless estimators that are associated with respective motors or electric drives of an aerial vehicle. Based on various detected faults, operations of affected motors may be modified, such as stopping operation or modifying motor control processes, in order to maintain safe flight and navigation of the aerial vehicle.

Claims (53)

1 . An aerial vehicle, comprising:

a body;

a plurality of motors associated with the body; and

a control system comprising a processor and a memory, the control system configured to at least:

receive a position sensor error determination associated with a first motor of the plurality of motors;

receive a sensorless error determination associated with the first motor;

receive a speed difference error determination associated with the first motor; and

responsive to at least one of the position sensor error determination, the sensorless error determination, or the speed difference error determination indicating a fault associated with the first motor, modify an operation of the first motor.

2 . The aerial vehicle of claim 1 , wherein the position sensor error determination indicates a fault associated with at least one position sensor that is associated with the first motor;

wherein the sensorless error determination indicates a fault associated with at least one sensorless estimator that is associated with the first motor; and

wherein the speed difference error determination indicates a fault associated with at least one of the at least one position sensor or the at least one sensorless estimator that is associated with the first motor.

3 . The aerial vehicle of claim 1 , wherein modifying the operation of the first motor comprises stopping operation of the first motor; and

wherein the control system is further configured to:

responsive to stopping operation of the first motor, execute a motor out aerial vehicle control process.

4 . The aerial vehicle of claim 1 , wherein modifying the operation of the first motor comprises selecting a healthy position sensor or sensorless estimator associated with the first motor; and

wherein the control system is further configured to:

responsive to selecting the healthy position sensor or sensorless estimator, continue operation of the first motor using data from the healthy position sensor or sensorless estimator.

5 . The aerial vehicle of claim 1 , wherein the control system is further configured to:

responsive to none of the position sensor error determination, the sensorless error determination, or the speed difference error determination indicating a fault associated with the first motor, continue operation of the first motor.

6 . A method for an aerial vehicle, comprising:

instructing a position sensor error determination associated with a position sensor of a first motor of a plurality of motors of an aerial vehicle;

instructing a sensorless error determination associated with a sensorless estimator of the first motor;

responsive to at least one of the position sensor error determination or the sensorless error determination indicating a fault associated with the first motor, modifying an operation of the first motor.

7 . The method of claim 6 , wherein the position sensor error determination indicates a fault associated with position and speed data measured by a single position sensor that is associated with the first motor.

8 . The method of claim 7 , wherein the fault is determined based at least in part on a sum of squares of a sine signal and a cosine signal measured by the single position sensor.

9 . The method of claim 6 , wherein the position sensor error determination indicates a fault associated with position and speed data measured by two position sensors that are associated with the first motor.

10 . The method of claim 9 , wherein the fault is determined based at least in part on:

a difference between a sine signal measured by a first position sensor of the two position sensors and a sine signal measured by a second position sensor of the two position sensors, or

a difference between a cosine signal measured by the first position sensor of the two position sensors and a cosine signal measured by the second position sensor of the two position sensors.

11 . The method of claim 6 , wherein the sensorless estimator error determination indicates a fault associated with position and speed data estimated by the sensorless estimator that is associated with the first motor.

12 . The method of claim 11 , wherein the fault is determined based at least in part on an angle error value calculated by the sensorless estimator.

13 . The method of claim 6 , further comprising:

instructing a speed difference error determination associated with at least one of the position sensor or the sensorless estimator of the first motor; and

14 . The method of claim 13 , wherein the speed difference error determination indicates a fault associated with at least one of speed data measured by the position sensor or speed data estimated by the sensorless estimator.

15 . The method of claim 14 , wherein the fault is determined based at least in part on a difference between the speed data measured by the position sensor and the speed data estimated by the sensorless estimator.

16 . The method of claim 6 , wherein the fault is determined based at least in part on a count of detected errors reaching or exceeding a threshold value, time, or time duration.

17 . A method, comprising:

receiving a position sensor error determination associated with a first motor of the plurality of motors of an aerial vehicle;

receiving a sensorless error determination associated with the first motor;

receiving a speed difference error determination associated with the first motor; and

18 . The method of claim 17 , wherein modifying the operation of the first motor further comprises:

stopping operation of the first motor; and

responsive to stopping operation of the first motor, executing a motor out aerial vehicle control process.

19 . The method of claim 17 , wherein a plurality of position sensors are associated with the first motor; and

wherein modifying the operation of the first motor further comprises:

selecting a healthy position sensor from the plurality of position sensors associated with the first motor; and

responsive to selecting the healthy position sensor, continuing operation of the first motor using data from the healthy position sensor.

20 . The method of claim 17 , wherein a plurality of sensorless estimators are associated with the first motor; and

wherein modifying the operation of the first motor further comprises:

selecting a healthy sensorless estimator from the plurality of sensorless estimators associated with the first motor; and

responsive to selecting the healthy sensorless estimator, continuing operation of the first motor using data from the healthy sensorless estimator.