Design of a high stiffness machining robot arm using double parallel mechanisms

Industrial robot has played a central role in the production automation such as welding, assembling, and painting. There has been however, little effort to the application of robots in machining works (grinding, cutting, milling, etc.) which are typical 3D works. The machining automation requires a high stiffness robot arm to reduce deformation and vibration. Conventional articulated robots serially connected links from the base to the gripper. So they have very weak structure for the machining work. Stewart platform is a typical parallel robotic mechanism with a very high stiffness but it has a small work space and a large installation space. This research proposes a new machining robot arm with a double parallel mechanism. It is composed of two platforms and a central axis. The central axis will connect the motions between the fist and the second platforms. Therefore, the robot has a large work space as well as a high stiffness. This paper will introduce the machining automation with a robot and design a machining robot arm using the double parallel mechanism