US 11,052,497 B2
Method and system for automatic assembly of curved surface part
Kaifu Zhang, Shaanxi (CN); Yi Cheng, Shaanxi (CN); Hui Cheng, Shaanxi (CN); Bin Luo, Shaanxi (CN); and Yuan Li, Shaanxi (CN)
Assigned to Northwestern Polytechnical University, Shaanxi (CN)
Appl. No. 16/96,088
Filed by Northwestern Polytechnical University, Shaanxi (CN)
PCT Filed Dec. 4, 2017, PCT No. PCT/CN2017/114445
§ 371(c)(1), (2) Date Oct. 24, 2018,
PCT Pub. No. WO2019/047393, PCT Pub. Date Mar. 14, 2019.
Claims priority of application No. 201710791969.9 (CN), filed on Sep. 5, 2017.
Prior Publication US 2020/0368859 A1, Nov. 26, 2020
Int. Cl. B23P 19/04 (2006.01); B25J 9/16 (2006.01); B25J 11/00 (2006.01); B25J 19/02 (2006.01); B25J 15/00 (2006.01); B25J 9/00 (2006.01)
CPC B23P 19/04 (2013.01) [B25J 9/0084 (2013.01); B25J 9/1682 (2013.01); B25J 9/1684 (2013.01); B25J 11/005 (2013.01); B25J 9/1694 (2013.01); B25J 15/0019 (2013.01); B25J 19/021 (2013.01); B25J 19/022 (2013.01); Y10T 29/4978 (2015.01); Y10T 29/49769 (2015.01); Y10T 29/49771 (2015.01)] 10 Claims
OG exemplary drawing
 
1. A method for automatic assembly of a curved surface part, comprising:
acquiring a central point of an execution end surface of an end effector;
acquiring a sensor plane formed by at least three sensors distributed on the end effector;
establishing a space coordinate system according to the central point and the sensor plane, wherein an origin of the space coordinate system is the central point, an x-y plane of the space coordinate system is the sensor plane, an axis z of the space coordinate system is a straight line on which a first unit normal vector is, the first unit normal vector being perpendicular to the x-y plane at the origin;
acquiring coordinates of three measurement points on the surface of a curved surface part in the space coordinate system, wherein the measurement points are intersections of the sensors and the surface of the curved surface part when the sensors collect information along a z-axis direction;
determining a curved surface expression of the surface of the curved surface part in the space coordinate system according to the coordinates of the measurement points;
calculating a second unit normal vector to the surface of the curved surface part according to the curved surface expression;
calculating a rotation angle of the end effector according to the first unit normal vector and the second unit normal vector; and
adjusting the end effector according to the rotation angle, such that a third unit normal vector of the end effector coincides with the second unit normal vector.