DESIGN AND FABRICATION OF INDUSTRIAL ROBOT FOR THE AUTOMOTIVE INDUSTRY

摘要

The Industrial Robot named "MECHRO" designed to pick and place objects of maximum one kg and used in the Automotive and Electronics Industry. Its main function is to pick the objects, lift it, move to a distance, orient it and then place the objects. This robot is provided with four degrees of freedom out of which one is the linear movement of the gripper and remaining three are rotary motions. The type of configuration used is the "SCARA CONFIGURATION" which is a combination of cylindrical configuration and revolute configuration operating in horizontal plane. The drive system incorporated is "The electrical drive system". This is accomplished by making use of stepper motors one for each axis. The distinct parts of "Mechro" are the upper arm, lower arm, the gripper and base. The arms are made of Aluminum and its houses the drive system consisting of motors, sprockets, chains and gears. The gripper is also made of Aluminum. Mild steel screw shaft at the end of the lower arm provides the linear movement of the gripper. The Base of "Robot" is made of a heavy material whose main function is to support whole unit in stable condition during operation. Stepper motors have been chosen to avoid feedback, reduce cost, and make the control system less complicated. The stepper motors were controlled through a computer. This facilities the programmer to write the control programme in any convenient language. On completion of Fabrication the experimental robot was assembled and tested for working. The motors were run and tested for the specified speed. The Gripper assembly was tested and the following results were inferred. The Gripper opening and closing was found to be 0-35 mm. The roll of the Gripper was 360°. For every revolution of the gripper the M-12 screw advanced by 1.7 mm (pitch) giving the vertical linear movement of the gripper. Next the rotations at the axes were examined and the rotation of the elbow axis was found to be equal to 255° and at the shoulder axis 360° rotation was obtained. The gripper was found to grip a load of 1 kg. The robot is command to move 20 inches and the actual move is measured and found to be 19.9 inches. The error is 0.10 inch and can be represented as an accuracy error of 0.5% less than the commanded distance. Key Words: Automotive Industrial Robot; SCARA Configuration; Four Degree of Freedom.