Rotation parameter detection method, encoder, laser radar and unmanned aerial vehicle

Patent metadata

Field	Value
Publication number	US-11320290-B2
Application number	US-202017110239-A
Country	US
Kind code	B2
Filing date	Dec 2, 2020
Priority date	Dec 12, 2017
Publication date	May 3, 2022
Grant date	May 3, 2022

Abstract

An encoder includes a code disc and a processor communicatively coupled with the code disc. The code disc is configured to rotate along with a rotating object and includes a plurality of fan teeth extending radially. One of the plurality of fan teeth is different from other ones of the plurality of fan teeth, and the other ones of the fan teeth are same to each other. A first portion of a detection signal that is generated in one rotation of the code disc, corresponding to the one of the plurality of fan teeth, is different from a second portion of the detection signal, corresponding to each of the other ones of the fan teeth. The processor is configured to detect the rotation of the code disc to obtain the detection signal and a rotation parameter of the rotating object based on the detection signal.

First claim

What is claimed is:

1. An encoder comprising:
a code disc configured to rotate along with a rotating object and including a plurality of fan teeth extending radially, wherein:
one of the plurality of fan teeth is different from other ones of the plurality of fan teeth, the other ones of the fan teeth being same to each other; and
a first portion of a detection signal that is generated in one round of rotation of the code disc, corresponding to the one of the plurality of fan teeth, is different from a second portion of the detection signal, corresponding to each of the other ones of the fan teeth; and

a processor communicatively coupled with the code disc and configured to:
detect the rotation of the code disc to obtain the detection signal; and
obtain a rotation parameter of the rotating object based on the detection signal, the rotation parameter including at least one of a rotation direction, a rotation speed, or a mechanical zero position,
wherein, in a rotation period of the rotating object:
the rotation direction is determined based on at least one of a time relationship between rising edges in the detection signal or a time relationship between falling edges in the detection signal;
the rotation speed is determined based on a duration of the detection signal; and
the mechanical zero position is determined based on at least one of the rising edges or the falling edges in the detection signal.

2. The encoder of claim 1 , further comprising a photo sensor communicatively coupled with the processor and configured to generate the detection signal, the photo sensor being disposed on a position adjacent to the code disc, wherein each of the fan teeth is configured to block the photo sensor for a period of time in the rotation period of the rotating object.

3. The encoder of claim 2 , wherein in the rotation period of the rotating object, the one of the fan teeth is configured to block the photo sensor for a first period of time, and each of the other ones of the fan teeth is configured to block the photo sensor for a second period of time, the second period of time being different from the first period of time.

4. The encoder of claim 3 , wherein the first period of time is greater than the second period of time.

5. The encoder of claim 2 , wherein the detection signal includes:
a continuous first signal that is detected when any of the fan teeth blocks the photo sensor, and
a continuous second signal detected when none of the fan teeth blocks the photo sensor, the first signal being different from the second signal.

6. The encoder of claim 5 , wherein the first signal includes a low-level signal and the second signal includes a high-level signal.

7. The encoder of claim 1 , wherein:
in the rotation period of the rotating object, the detection signal includes a plurality of square wave cycles, each of the square wave cycles including a low-level period each corresponding to one fan tooth of the plurality of fan teeth and a high-level period, and
the processor is further configured to determine the rotation direction based a time relationship between the low-level periods and the high-level periods.

8. The encoder of claim 1 , wherein:
each of the fan teeth includes a first line segment edge, a second line segment edge, and a first arc edge along a circumference of the code disc and connecting the first line segment edge and the second line segment edge;
the first line segment edges of the fan teeth are arranged at the code disc with equal intervals; and
a length of the arc edge of the one of the fan teeth is different from lengths of the arc edges of the other ones of the fan teeth, and the lengths of the arc edges of the other ones of the fan teeth equal each other.

9. The encoder of claim 8 , wherein the processor is further configured to determine the rotation direction based on at least one of the time relationship between the rising edges in the detection signal or the time relationship between the falling edges in the detection signal.

10. The encoder of claim 9 , wherein:
for each of the fan teeth, the first line segment edge is disposed in a clockwise direction with respect to the second line segment edge; and
the processor is further configured to determine the rotation direction to be counterclockwise in response to determining that:
the rising edges are equally separated in time in the rotation period, or
the falling edges are not always equally separated in time in the rotation period.

11. The encoder of claim 9 , wherein:
for each of the fan teeth, the first line segment edge is disposed in a clockwise direction with respect to the second line segment edge; and
the processor is further configured to determine the rotation direction to be clockwise in response to determining that:
the falling edges are equally separated in time in the rotation period, or
the rising edges are not always equally separated in time in the rotation period.

12. The encoder of claim 9 , wherein:
for each of the fan teeth, the first line segment edge is disposed in a counterclockwise direction with respect to the second line segment edge; and
the processor is further configured to determine the rotation direction to be clockwise in response to determining that:
the rising edges are equally separated in time in the rotation period, or
the falling edges are not always equally separated in time in the rotation period.

13. The encoder of claim 9 , wherein:
for each of the fan teeth, the first line segment edge is disposed in a counterclockwise direction with respect to the second line segment edge; and
the processor is further configured to determine the rotation direction to be counterclockwise in response to determining that:
the falling edges are equally separated in time in the rotation period, or
the rising edges are not always equally separated in time in the rotation period.

14. The encoder of claim 1 , wherein the processor is further configured to determine the rotation speed based on at least one of a time relationship between the rising edges in the detection signal or a time relationship between the falling edges in the detection signal in the rotation period of the rotating object.

15. The encoder of claim 14 , wherein the processor is further configured to:
obtain time differences, each of the time differences being between two adjacent ones of the rising edges or between two adjacent ones of the falling edges;
obtain an average time difference based on the time differences; and
determine the rotation speed based on the average time difference.

16. The encoder of claim 14 , wherein the processor is further configured to determine the rotation speed based on:
a time difference between any two adjacent ones of the rising edges in response to the rising edges being equally separated in time in the rotation period; or
a time difference between any two adjacent ones of the falling edges in response to the falling edges being equally separated in time in the rotation period.

17. The encoder of claim 1 , wherein the processor is further configured to determine the mechanical zero position based on the at least one of the rising edges or the falling edges in the detection signal in the rotation period of the rotating object.

18. The encoder of claim 17 , wherein the processor is further configured to, in response to the rising edges not always being equally separated in time in the rotation period:
determine a reference rising edge based on a time relationship between the rising edges in the rotation pe

Assignees

• Sz Dji Technology Co Ltd

Inventors

• Liu Wanqi
• Lan Qiu
• Zhou Changxing

Classifications

• G01P13/045

  with speed indication · CPC title

• G01S7/481

  Constructional features, e.g. arrangements of optical elements · CPC title

• G01D5/3473 Primary

  Circular or rotary encoders · CPC title

• G01P13/02

  Indicating direction only, e.g. by weather vane · CPC title

• G01P3/486

  delivered by photo-electric detectors · CPC title