Design and implementation of a roll mechanism and tool interface (RMTI) for a robotic arm

This paper discusses the complete design of a special type of robot end effector with some unique features which make it more reliable and expandable. The Roll Mechanism and Tool Interface (RMTI) performs a continuous roll motion with a maximum twisting torque capability ranging between 90 and 100 Ib-in. It has a built-in accurate parallel type end effector with an opening range from 0 to 3 inches. The maximum squeeze force that can be produced between the tongs of the end effector is 40-lbs. In addition, the end effecter consits of interchangeable digits, which form the gripper, without operator intervention. This way, many other types of tongs or tools can be used. However, for testing purposes, the prototype was built with regular tongs each of which has a grab area of 2.5" x 1". Futhermore, the overall mechanical design volume was kept under 4 in^ and the RMTI weight was minimized. The maximum payload of the RMTI is around 30-lbs and it is capable of withstanding a maximum axial force of equal magnitude. Enhancement and aesthetics of the design are required and the cost must be kept down as much as possible. The minimum size of the object that can be manipulated under maximum loading conditions is 0.25".