A Real-Time Algorithm for Determining the Optimal Paint Gun Orientation in Spray Paint Applications

In this paper, we present a method for increasing the speed at which a standard industrial manipulator can paint a surface. The approach is based on the observation that a small error in the orientation of the end effector does not affect the quality of the paint job. It is far more important to maintain constant velocity throughout the trajectory. We consider the freedom in the end-effector orientation as functional redundancy and represent the restriction on the orientation error as barrier functions or linear matrix inequalities. In doing this, we cast the problem of finding the optimal orientation at every time step into a convex optimization problem that can be solved very efficiently and in real time. We show that the approach allows the end effector to maintain a higher constant velocity throughout the trajectory guaranteeing uniform paint coating and substantially reducing the time needed to paint the object.