Process for Painting a Workpiece Comprising Generating a Trajectory Suitable for the Actual Workpiece

A process for painting a workpiece by using a painting robot comprising a robotic arm equipped with a paint spraying device, the process comprising:

• (1) a primary operation of modeling a realistic 3D model comprising information on the paint trajectory, comprising:
• (10) determining reference coordinates of at least three model characteristic points on a nominal 3D model of the workpiece to be painted, the coordinates of the model characteristic points being expressed in a reference frame;
• (20) detecting at least three actual characteristic points on the workpiece, the actual characteristic points corresponding on the workpiece to one of the model characteristic points, respectively, as determined on the nominal 3D model during (10);
• (30) transposing coordinates of actual characteristic points and coordinates of the model characteristic points into a common frame of reference;
• and
• (40) generating a realistic 3D model corresponding to the workpiece as deformed and positioned in a paint cell, by applying stress simulations to the nominal 3D model leading to deformations which move the model characteristic points toward the respective coordinates of their corresponding actual characteristic point thereof, so as to match the position of the model characteristic points with respect to the nominal 3D model with the position of the actual characteristic points with respect to the realistic 3D model;
• and
• (2) a primary operation of paint spraying during which the paint spraying device is moved along the paint trajectory opposite the workpiece.