Design and construction of a linear-rotary joint for robotics applications

In this paper the mechanical design process of a special linear-rotary joint for a SCARA robot, called FUM SCARA, is illustrated. FUM SCARA is constructed in the Robotics Lab of Ferdowsi University of Mashhad, in Iran. Main features of this robot are overall ±0.015 mm repeatability in XYZ plane, 8.5 m/s end-effector velocity and 0.5 seconds full pick and place cycle time. FUM SCARA robot is capable of doing applications such as pick and place and assembly in production lines using a custom designed linear-rotary joint. SCARA is a common industrial robot with inherent high joint repeatability and rigidity. As a result, repeatability of the proposed joint is essential. To pick up and place a work piece, a vacuum system tubing must be designed into the linear-rotary joint. Mechanical design process, includes linear-rotary joint design and selection of the required components. The effectiveness of the presented joint and the robot is investigated through experimental and simulation results.