Spray painting of a general three-dimensional surface

An economic automatic system for spray painting of a general three dimensional surface is described. The spray gun is mounted on the wrist of a six degree of freedom (6 DOF) industrial robot. The system functions by the method of camera space manipulation, using two CCD cameras to scan the surface dimensions off-line, and store them in a supervisory computer in the form of nodes. An inverse kinematic program is developed and stored in the computer to calculate the trajectories of the six joints corresponding to the nodes on the surface, to acquire the correct position and orientation of the spray nozzle. The values of the joint angles are fed to the controllers of the joint motors every time interval, depending on the number of nodes and the required spray painting rate. Sensors inform the computer of the presence of the surface as well as of the home position and end of trajectory. The computer also receives sensory data from the motor controllers as spray painting of the workpiece is accomplished. The position and velocity trajectories of two surfaces with different geometries (rectangular and hemispherical) are calculated using the proposed algorithm, and plotted for each of the six joints angles.