An Autonomous Robotic Cell for Painting Applications

Normally industrial painting robots have an articulated structure and have six degrees of freedom (DOF). This project investigated a 3 DOF robot for painting vertical objects of different colors. The proposed project utilized a SCARA type robot which has stiffness in the vertical direction and the largest workspace in industrial applications. The gripper of the robot was replaced with an end-effector which was designed to hold a color sensor and an automatic spray gun. The color sensor detects the color to be painted from a sticker pasted on the corner of the object and gives a signal to the Programmable Logic Controller (PLC) for selecting the proper container in the tank reservoir. A painting reservoir, consists of different painting tanks, was attached to the robot as a mobile unit and an electronic switch was utilized to direct the cable to the selected color based on the signal from the color sensor. The equatıons of motıon for the SCARA robot is presented based on the Lagrange-Euler technique. The joints trajectory are designed as fifth-order polynomials to estimate the required torques and linear force for actuators. Performance analysis for accurate and homogeneous painting is provided.