Motion target direction angle obtaining method, apparatus and robot using the same

1. A computer-implemented direction angle obtaining method for a motion object, comprising executing on a processor the steps of:

creating an absolute coordinate system, and obtaining an absolute position coordinate of at least one point after the first point in the absolute coordinate system, wherein the first point and the at least one point are points on a motion trajectory of the motion target, and the points are obtained through an absolute positioning method;

creating a relative coordinate system with the first point as an origin, and obtaining a relative position coordinate corresponding to the at least one point in the relative coordinate system, wherein the relative position coordinate is a coordinate of a point of the motion target obtained by a relative positioning method;

calculating matrix parameters of a transformation matrix based on the absolute position coordinate of the at least one point and the relative position coordinate corresponding to the at least one point, wherein the transformation matrix is for transforming between the absolute coordinate system and the relative coordinate system; and

determining a direction angle of the motion target at the first point based on the matrix parameters.

2. The method of claim 1 , wherein the step of calculating the matrix parameters of the transformation matrix based on the absolute position coordinate of the at least one point and the relative position coordinate corresponding to the at least one point comprises:

creating a matrix equation corresponding to each point based on the absolute position coordinate of each point, the relative position coordinate of each point, and the transformation matrix;

composing the matrix equation corresponding to each point into overdetermined equations; and

solving the overdetermined equations to obtain the matrix parameters of the transformation matrix.

3. The method of claim 2 , wherein the step of solving the overdetermined equations to obtain the matrix parameters of the transformation matrix comprises:

decoupling the overdetermined equations; and

solving the decoupled overdetermined equations based on a least squares method to obtain the matrix parameters of the transformation matrix.

4. The method of claim 2 , wherein the transformation matrix is for transforming the absolute coordinate system to the relative coordinate system, and the equation of the transformation matrix is:

[

x

map

i

y

map

i

1

0

y

map

i

-

x

map

i

0

1

]

⁡

[

cos

⁡

(

θ

)

sin

⁡

(

θ

)

m

n

]

=

[

x

odom

i

y

odom

i

]

where, (x map i ,y map i ) is the absolute position coordinate of the i-th point; (x odom i ,y odom i ) is the relative position coordinate of the i-th point; and θ, m, and n are the matrix parameters.

5. The method of claim 1 , wherein the absolute positioning method comprises positioning the motion target through distances between the motion target and a plurality of base stations.

6. The method of claim 1 , wherein the relative positioning method comprises positioning the motion target through an odometer disposed on the motion target, wherein the relative coordinate system comprises an odometer coordinate system of the odometer.

7. The method of claim 1 , wherein the motion target is a robot.

8. A direction angle obtaining apparatus for a motion target, comprising:

a first creating module configured to create an absolute coordinate system, and obtain an absolute position coordinate of at least one point after the first point in the absolute coordinate system, wherein the first point and the at least one point are points on a motion trajectory of the motion target, and the points are obtained through an absolute positioning method;

a second creating module configured to create a relative coordinate system with the first point as an origin, and obtain a relative position coordinate corresponding to the at least one point in the relative coordinate system, wherein the relative position coordinate is a coordinate of a point of the motion target obtained by a relative positioning method;

a first processing module configured to calculate matrix parameters of a transformation matrix based on the absolute position coordinate of the at least one point and the relative position coordinate corresponding to the at least one point, wherein the transformation matrix is for transforming between the absolute coordinate system and the relative coordinate system; and

a second processing module configured to determine a direction angle of the motion target at the first point based on the matrix parameters.

9. The apparatus of claim 8 , wherein the first processing module is configured to calculate the matrix parameters of the transformation matrix by:

creating a matrix equation corresponding to each point based on the absolute position coordinate of each point, the relative position coordinate of each point, and the transformation matrix;

composing the matrix equation corresponding to each point into overdetermined equations; and

solving the overdetermined equations to obtain the matrix parameters of the transformation matrix.

10. The apparatus of claim 9 , wherein the first processing module is configured to solve the overdetermined equations to obtain the matrix parameters of the transformation matrix by:

decoupling the overdetermined equations; and

solving the decoupled overdetermined equations based on a least squares method to obtain the matrix parameters of the transformation matrix.

11. The apparatus of claim 9 , wherein the transformation matrix is for transforming the absolute coordinate system to the relative coordinate system, and the equation of the transformation matrix is:

[

x

map

i

y

map

i

1

0

y

map

i

-

x

map

i

0

1

]

⁡

[

cos

⁡

(

θ

)

sin

⁡

(

θ

)

m

n

]

=

[

x

odom

i

y

odom

i

]

where, (x map i ,y map i ) is the absolute position coordinate of the i-th point; (x odom i ,y odom i ) is the relative position coordinate of the i-th point; and θ, m, and n are the matrix parameters.

12. The apparatus of claim 8 , wherein the absolute positioning method comprises positioning the motion target through distances between the motion target and a plurality of base stations.

13. The apparatus of claim 8 , wherein the relative positioning method comprises positioning the motion target through an odometer disposed on the motion target, wherein the relative coordinate system comprises an odometer coordinate system of the odometer.

14. The apparatus of claim 8 , wherein the motion target is a robot.

15. A robot comprising:

a memory;

a processor, and

one or more computer programs stored in the memory and executable on the processor, wherein the one or more computer programs comprise:

instructions for creating an absolute coordinate system, and obtaining an absolute position coordinate of at least one point after the first point in the absolute coordinate system, wherein the first point and the at least one point are points on a motion trajectory of the robot, and the points are obtained through an absolute positioning method;

instructions for creating a relative coordinate system with the first point as an origin, and obtaining a relative position coordinate corresponding to the at least one point in the relative coordinate system, wherein the relative position coordinate is a coordinate of a point of the robot obtained by a relative positioning method;

instructions for calculating matrix parameters of a transformation matrix based on the absolute position coordinate of the at least one point and the relative position coordinate corresponding to the at least one point, wherein the transformation matrix is for transforming between the absolute coordinate system and the relative coordinate system; and

instructions for determining a direction angle of the robot at the first point based on the matrix parameters.

16. The robot of claim 15 , wherein the instructions for calculating the matrix parameters of the transformation matrix based on the absolute position coordinate of the at least one point and the relative position coordinate corresponding to the at least one point comprise:

instructions for creating a matrix equation corresponding to each point based on the absolute position coordinate of each point, the relative position coordinate of each point, and the transformation matrix;

instructions for composing the matrix equation corresponding to each point into overdetermined equations; and

instructions for solving the overdetermined equations to obtain the matrix parameters of the transformation matrix.

17. The robot of claim 16 , wherein the instructions for solving the overdetermined equations to obtain the matrix parameters of the transformation matrix comprise:

instructions for decoupling the overdetermined equations; and

instructions for solving the decoupled overdetermined equations based on a least squares method to obtain the matrix parameters of the transformation matrix.

18. The robot of claim 16 , wherein the transformation matrix is for transforming the absolute coordinate system to the relative coordinate system, and the equation of the transformation matrix is:

[

x

map

i

y

map

i

1

0

y

map

i

-

x

map

i

0

1

]

⁡

[

cos

⁡

(

θ

)

sin

⁡

(

θ

)

m

n

]

=

[

x

odom

i

y

odom

i

]

where, (x map i ,y map i ) is the absolute position coordinate of the i-th point; (x odom i ,y odom i ) is the relative position coordinate of the i-th point; and θ, m, and n are the matrix parameters.

19. The robot of claim 15 , wherein the absolute positioning method comprises positioning the robot through distances between the robot and a plurality of base stations.

20. The robot of claim 15 , wherein the robot further comprises an odometer, and the relative positioning method comprises positioning the robot through the odometer, wherein the relative coordinate system comprises an odometer coordinate system of the odometer.