Construction of a Selective Compliance Articulated Robot Arm : And evaluation of its accuracy

Abstract: The concept of a robotic manipulator is widely used throughout many industries. In this project, a manipulator of the type SCARA, selective compliance articulated robot arm, is constructed. The aim was to examine how such a robot could be constructed using 3D-printing and how accurate it would be. Other than 3D-printing, parts in the form of guiding rods, lead screw, bearings, pulleys and timing belts were used. Together with a microcontroller, the robot operates using three stepper motors. In the end it resulted in a SCARA with reasonable accuracy considering the methods used, more specifically the largest average error was 3.6cm in the X direction and 2.3 cm in the Y direction. The largest drawback of the final construction was the negative balance between tightening the belts and friction in the inner joint. Tightening the belts meant larger friction and thereby undesired movement properties. Doing the opposite meant that the belts could start slipping and enabled backlash.