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:

• modeling a realistic 3D model comprising information on a paint trajectory, comprising:
• determining reference coordinates of positions of at least three model characteristic points on a nominal 3D model of the workpiece to be painted, with reference to a model reference frame;
• detecting coordinates of positions of at least three actual characteristic points on the workpiece, each actual characteristic point on the workpiece corresponding to a respective one of the model characteristic points, as determined on the nominal 3D model during said determining;
• transforming coordinates of actual characteristic points and coordinates of the model characteristic points into a common frame of reference;
• and
• generating a realistic 3D model corresponding to the workpiece as deformed and positioned in a paint cell, by applying mechanical stress simulations to the nominal 3D model leading to computed deformations which move the model characteristic points toward their corresponding actual characteristic points, so as to match the positions of the model characteristic points with respect to the nominal 3D model with the positions of the actual characteristic points with respect to the realistic 3D model;
• and
• spraying paint, comprising moving the spraying device opposite the workpiece along the paint trajectory.