A gantry platform control method applied to a gantry platform device which comprises a crossbeam, a first guide rail and a second guide rail, wherein one end of the crossbeam is in sliding fit with the first guide rail, and the other end of the crossbeam is in sliding fit with the second guide rail;
- the first guide rail is provided with a first longitudinal motor, the second guide rail is provided with a second longitudinal motor, and the first longitudinal motor and the second longitudinal motor are respectively connected to two ends of the crossbeam;
- and the crossbeam is provided with a transverse motor configured to drive the gantry platform to move along the crossbeam;
- and
- a gantry platform kinematics modeling method considering parallelism and perpendicularity errors comprises the following steps:
- (1) establishing a two-dimensional coordinate system
- taking the first guide rail as a reference guide rail and an initial position of the first longitudinal motor as an origin to establish a two-dimensional coordinate system O0 in a plane at which the first guide rail and the second guide rail are located, wherein in the coordinate system, a coordinate of the first longitudinal motor after movement is Y1′ (0, y1), a coordinate of the second longitudinal motor after movement is Y2′ (x2, y2), and a position coordinate of the gantry platform after movement is (x, y);
- and
- a length of the crossbeam is 1, a parallelism error between the first guide rail and the second guide rail is α, and a perpendicularity error between the crossbeam and the first guide rail at the initial position of the first motor is β0;
- (2) constructing a forward kinematics solution model
- it is given that moved displacements of the first longitudinal motor, the second longitudinal motor and the transverse motor are ye1, ye2, xe, and an initial offset of the transverse motor is xz0, solving displacements xr, yr of the gantry platform as follows:
- {
- x
- r
- =
- x
- e
-
- 1
-
- cos
-
- β
- 0
- y
- r
- =
- xy
- 2
- -
- xy
- 1
- +
- x
- 2
-
- y
- 1
- x
- 2
- -
- x
- z
-
- 0
-
- β
- 0
- ;
- equation
-
- (
- 1
- -
- 4
- )
- and
- (3) constructing an inverse kinematics solution model
- it is given that the displacements of the gantry platform are xr, yr solving required displacements ye1, ye2, xe for the first longitudinal motor, the second longitudinal motor and the transverse motor to move:
- {
- y
- e
-
- 1
- =
- y
- 1
- y
- e
-
- 2
- =
- y
- 2
- -
- l
-
- β
- 0
- cos
-
- α
- x
- e
- =
- x
- r
- cos
-
- β
- ,
- equation
-
- (
- 1
- -
- 9
- )
- wherein β is a perpendicularity error after movement;
- wherein the gantry platform control method comprises the following steps:
- acquiring expected displacements xr, yr of the gantry platform after movement;
- obtaining the required displacements xe, ye1, ye2 for the transverse motor, the first longitudinal motor and the second longitudinal motor to move by using the inverse kinematics solution mode;
- controlling the movement of the first longitudinal motor, the second longitudinal motor and the transverse motor;
- acquiring actual displacements xt1, yt1, yt2 of the transverse motor, the first longitudinal motor and the second longitudinal motor;
- obtaining an actual position (x, y) of the gantry platform after movement by using the forward kinematics solution model;
- and
- compensating for a deviation between an expected position (xr, yr) and the actual position (x, y) of the gantry platform after movement.