The invention provides a control method for a fitting gap of an exterior curved surface of a repair
welding position of a
storage tank, which comprises the following steps: S1, extracting spatial three-dimensional coordinates of n points uniformly distributed around a defect area from three-dimensional scanning
point cloud data of the exterior curved surface of the
storage tank, and defining the geometric center of the defect area as a defect center; s2, based on the defect center, mapping the space three-dimensional coordinates of the n points extracted in the step S1 to a
robot tool coordinate
system through a coordinate conversion relation to obtain converted coordinates of n target points; s3, calculating a three-dimensional space error value between the converted coordinates of the target point and the coordinates of the corresponding point on the supporting tool; s4, iteratively optimizing the error value in a
robot joint
kinematics constraint range, solving an optimal support tool space coordinate, and taking the coordinate as a
robot motion target point; and S5,
joint coordinates corresponding to the moving target point of the robot are transmitted to a
robot controller through the real-time industrial
bus communication technology, and the mechanical arm is driven to drive the supporting tool to move to the target point.