# US 11,346,648 B2 · Rotation angle detection method and device thereof

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- Number: US 11,346,648 B2
- Document ID: US11346648B2
- Status: Granted
- Kind: B2
- Application number: 16/626,519
- Filed: 2018-12-29
- Published: 2021-10-28
- Granted: 2022-05-31
- Earliest claimed: 2018-12-29
- Assignees: Ubtech Robotics Corp Ltd
- Applicants: Ubtech Robotics Corp Ltd
- Inventors: Xi Bai; Wenhua Fan; Malin Wang; Youjun Xiong
- Web page: https://patentgrep.com/patent/US11346648B2

## CPC

- G01B 5/24: for measuring angles or tapers; for testing the alignment of axes
- G01D 3/036: on measuring arrangements themselves
- G01D 5/24485: {using other sensors}
- G05B 19/416: characterised by control of velocity, acceleration or deceleration (G05B19/19 takes precedence)
- H02P 21/18: Estimation of position or speed
- G05B 2219/41036: Position error in memory, lookup table for correction actual position
- G01B: MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01D: MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
- G05B: CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS (systems for controlling or regulating non-electric variables G05D; systems for regulating electric or magnetic variables G05F; control devices or systems insofar as characterised by mechanical features only G05G)
- H02P: CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS

## Abstract

The present invention provides a rotation angle detection method and device thereof. The method includes calculating an estimated value of a rotation angle of a motor shaft during rotation according to a second rotation angle; determining an actual range of the rotation angle according to the estimated value of the rotation angle and a detection error of the second angle sensor; determining optional values of the rotation angle based on a relative relationship between a first rotation angle and the estimated value; determining an actual rotation angle of the motor shaft, based on a value falling within the actual range of the rotation angle among the optional values, and determining an actual rotation angle of the output shaft according to the actual rotation angle of the motor shaft. The present invention can improve the measurement accuracy of the rotation angles of the output shaft of the rotating mechanism.

## Claims

### Claim 1

A rotation angle detection method, applied to a rotating mechanism comprising a motor shaft, a transmission part, and an output shaft, an output torque of the motor shaft acting on the output shaft through the transmission part, and driving the output shaft to rotate, wherein a first angle sensor is arranged on the motor shaft of the rotating mechanism for detecting a first rotation angle of the motor shaft, a second angle sensor is arranged on the output shaft of the rotating mechanism for detecting a second rotation angle of the output shaft; the method comprising:
calculating an estimated value of a rotation angle of the motor shaft during rotation according to the second rotation angle;
determining an actual range of the rotation angle of the motor shaft, according to the estimated value of the rotation angle and a detection error of the second angle sensor;
determining optional values of the rotation angle of the motor shaft, based on a relative relationship between the first rotation angle and the estimated value of the rotation angle; and
determining an actual rotation angle of the motor shaft, based on a value falling within the actual range of the rotation angle of the motor shaft among the optional values of the rotation angle, and determining an actual rotation angle of the output shaft according to the actual rotation angle of the motor shaft;
wherein before the step of calculating the estimated value of the rotation angle of the motor shaft during rotation according to the second rotation angle, further comprises:
calculating a rotation angle corresponding relationship between the motor shaft and the output shaft, according to a transmission ratio of the transmission part;
determining an estimated rotation number of the motor shaft, based on the second rotation angle and the rotation angle corresponding relationship between the motor shaft and the output shaft; and
determining an estimated value of a real-time rotation angle of the motor shaft, based on the second rotation angle and the rotation angle corresponding relationship between the motor shaft and the output shaft; and
wherein the step of calculating the estimated value of the rotation angle of the motor shaft during rotation according to the second rotation angle comprises:
determining the estimated value of the rotation angle by adding a product of the estimated rotation number and 360° to a product of the estimated value of the real-time rotation angle and the transmission ratio.

### Claim 2 (depends on 1)

The method as claimed in claim 1, wherein the step of determining the actual range of the rotation angle of the motor shaft, according to the estimated value of the rotation angle and the detection error of the second angle sensor, comprises:
obtaining a measurement error value of the second angle sensor;
determining the actual range of the rotation angle of the motor shaft, according to a sum of the estimated value of the rotation angle and the measurement error value, and a difference between the estimated value of the rotation angle and the measurement error value.

### Claim 3 (depends on 1)

The method as claimed in claim 1, wherein the estimated value of the rotation angle comprises an estimated rotation number, and an estimated value of the real-time rotation angle;
the step of determining the optional values of the rotation angle of the motor shaft, based on the relative relationship between the first rotation angle and the estimated value of the rotation angle, comprises:
determining a corresponding relationship between the estimated rotation number and an actual rotation number of the motor shaft; and
performing an angle value conversion according to the first rotation angle and the actual rotation number, and obtaining the optional values of the rotation angle.

### Claim 4 (depends on 3)

The method as claimed in claim 3, wherein the optional values of the rotation angle comprise: a first rotation angle, a second rotation angle, and a third rotation angle;
the step of determining the actual rotation angle of the motor shaft, based on the value falling within the actual range of the rotation angle of the motor shaft among the optional values of the rotation angle, comprises:
calculating sizes of the first rotation angle, the second rotation angle and the third rotation angle, and determining any one of the optional values of the rotation angle falling within the actual range of the rotation angle of the motor shaft as the actual rotation angle of the motor shaft.

### Claim 5 (depends on 1)

The method as claimed in claim 1, wherein the step of determining the actual rotation angle of the output shaft according to the actual rotation angle of the motor shaft, comprises:
obtaining a transmission ratio of the transmission part corresponding to the output torque of the motor shaft, dividing the actual rotation angle of the motor shaft by the transmission ratio, and obtaining the actual rotation angle of the output shaft.

### Claim 6

A rotation angle detection device, comprising:
a rotation angle estimating module, configured for calculating an estimated value of a rotation angle of a motor shaft during rotation according to a second rotation angle;
an actual range determining module, configured for determining an actual range of the rotation angle of the motor shaft, according to the estimated value of the rotation angle and a detection error of the second angle sensor;
an angle calculating module, configured for determining optional values of the rotation angle of the motor shaft, based on a relative relationship between a first rotation angle and the estimated value of the rotation angle, and
an angle selecting module, configured for determining an actual rotation angle of the motor shaft, based on a value falling within the actual range of the rotation angle of the motor shaft among the optional values of the rotation angle, and determining an actual rotation angle of the output shaft according to the actual rotation angle of the motor shaft;
wherein before calculating the estimated value of the rotation angle of the motor shaft during rotation according to the second rotation angle, the rotation angle estimating module is further configured for:
calculating a rotation angle corresponding relationship between the motor shaft and the output shaft, according to a transmission ratio of the transmission part;
determining an estimated rotation number of the motor shaft, based on the second rotation angle and the rotation angle corresponding relationship between the motor shaft and the output shaft; and
determining an estimated value of a real-time rotation angle of the motor shaft, based on the second rotation angle and the rotation angle corresponding relationship between the motor shaft and the output shaft; and
wherein calculating the estimated value of the rotation angle of the motor shaft during rotation according to the second rotation angle, comprises:
determining the estimated value of the rotation angle, by adding a product of the estimated rotation number and 360° to a product of the estimated value of the real-time rotation angle and the transmission ratio.

### Claim 7 (depends on 1)

A terminal, wherein the terminal comprises a processor and a non-transitory storage storing computer programs which when executed by the processor cause the processor to perform steps of the method of claim 1.

### Claim 8 (depends on 1)

A non-transitory computer readable storage medium storing computer programs, wherein when the computer programs are executed by a processor, steps of the method of claim 1 are performed.

### Claim 9 (depends on 6)

The rotation angle detection device as claimed in claim 6, wherein determining the actual range of the rotation angle of the motor shaft, according to the estimated value of the rotation angle and the detection error of the second angle sensor, comprises:
obtaining a measurement error value of the second angle sensor; and
determining the actual range of the rotation angle of the motor shaft, according to a sum of the estimated value of the rotation angle and the measurement error value, and a difference between the estimated value of the rotation angle and the measurement error value.

### Claim 10 (depends on 6)

The rotation angle detection device as claimed in claim 6, wherein the estimated value of the rotation angle comprises an estimated rotation number, and an estimated value of the real-time rotation angle; and
wherein determining the optional values of the rotation angle of the motor shaft, based on the relative relationship between the first rotation angle and the estimated value of the rotation angle, comprises:
determining a corresponding relationship between the estimated rotation number and an actual rotation number of the motor shaft; and
performing an angle value conversion according to the first rotation angle and the actual rotation number, and obtaining the optional values of the rotation angle.

### Claim 11 (depends on 10)

The rotation angle detection device as claimed in claim 10, wherein the optional values of the rotation angle comprise: a first rotation angle, a second rotation angle, and a third rotation angle; and
wherein determining the actual rotation angle of the motor shaft, based on the value falling within the actual range of the rotation angle of the motor shaft among the optional values of the rotation angle, comprises:
calculating sizes of the first rotation angle, the second rotation angle and the third rotation angle, and determining any one of the optional values of the rotation angle falling within the actual range of the rotation angle of the motor shaft as the actual rotation angle of the motor shaft.

### Claim 12 (depends on 6)

The rotation angle detection device as claimed in claim 6, wherein determining the actual rotation angle of the output shaft according to the actual rotation angle of the motor shaft, comprises:
obtaining a transmission ratio of the transmission part corresponding to the output torque of the motor shaft, dividing the actual rotation angle of the motor shaft by the transmission ratio, and Obtaining the actual rotation angle of the output shaft.

### Claim 13 (depends on 7)

The terminal as claimed in claim 7, wherein the step of determining the actual range of the rotation angle of the motor shaft, according to the estimated value of the rotation angle and the detection error of the second angle sensor, comprises:
obtaining a measurement error value of the second angle sensor;
determining the actual range of the rotation angle of the motor shaft, according to a sum of the estimated value of the rotation angle and the measurement error value, and a difference between the estimated value of the rotation angle and the measurement error value.

### Claim 14 (depends on 7)

The terminal as claimed in claim 7, wherein the estimated value of the rotation angle comprises an estimated rotation number, and an estimated value of the real-time rotation angle;
the step of determining the optional values of the rotation angle of the motor shaft, based on the relative relationship between the first rotation angle and the estimated value of the rotation angle, comprises:
determining a corresponding relationship between the estimated rotation number and an actual rotation number of the motor shaft; and
performing an angle value conversion according to the first rotation angle and the actual rotation number, and obtaining the optional values of the rotation angle.

### Claim 15 (depends on 14)

The terminal as claimed in claim 14, wherein the optional values of the rotation angle comprise: a first rotation angle, a second rotation angle, and a third rotation angle;
the step of determining the actual rotation angle of the motor shaft, based on the value falling within the actual range of the rotation angle of the motor shaft among the optional values of the rotation angle, comprises:
calculating sizes of the first rotation angle, the second rotation angle and the third rotation angle, and determining any one of the optional values of the rotation angle falling within the actual range of the rotation angle of the motor shaft as the actual rotation angle of the motor shaft.

### Claim 16 (depends on 7)

The terminal as claimed in claim 7, wherein the step of determining the actual rotation angle of the output shaft according to the actual rotation angle of the motor shaft, comprises:
obtaining a transmission ratio of the transmission part corresponding to the output torque of the motor shaft, dividing the actual rotation angle of the motor shaft by the transmission ratio, and obtaining the actual rotation angle of the output shaft.

### Claim 17 (depends on 8)

The non-transitory computer readable storage medium as claimed in claim 8, wherein the step of determining the actual range of the rotation angle of the motor shaft, according to the estimated value of the rotation angle and the detection error of the second angle sensor, comprises:
obtaining a measurement error value of the second angle sensor; and
determining the actual range of the rotation angle of the motor shaft, according to a sum of the estimated value of the rotation angle and the measurement error value, and a difference between the estimated value of the rotation angle and the measurement error value.

### Claim 18 (depends on 8)

The non-transitory computer readable storage medium as claimed in claim 8, wherein the estimated value of the rotation angle comprises an estimated rotation number, and an estimated value of the real-time rotation angle;
the step of determining the optional values of the rotation angle of the motor shaft, based on the relative relationship between the first rotation angle and the estimated value of the rotation angle, comprises:
determining a corresponding relationship between the estimated rotation number and an actual rotation number of the motor shaft; and
performing an angle value conversion according to the first rotation angle and the actual rotation number, and obtaining the optional values of the rotation angle.

### Claim 19 (depends on 18)

The non-transitory computer readable storage medium as claimed in claim 18, wherein the optional values of the rotation angle comprise: a first rotation angle, a second rotation angle, and a third rotation angle;
the step of determining the actual rotation angle of the motor shaft, based on the value falling within the actual range of the rotation angle of the motor shaft among the optional values of the rotation angle, comprises:
calculating sizes of the first rotation angle, the second rotation angle and the third rotation angle, and determining any one of the optional values of the rotation angle falling within the actual range of the rotation angle of the motor shaft as the actual rotation angle of the motor shaft.

### Claim 20 (depends on 8)

The non-transitory computer readable storage medium as claimed in claim 8, wherein the step of determining the actual rotation angle of the output shaft according to the actual rotation angle of the motor shaft, comprises:
obtaining a transmission ratio of the transmission part corresponding to the output torque of the motor shaft, dividing the actual rotation angle of the motor shaft by the transmission ratio, and Obtaining the actual rotation angle of the output shaft.