Basic study on the characteristics of a singular mechanism and its application to the robot arm

Abstract

This paper shows a singular mechanism for a gravity compensated and reactionless robot arm. Firstly, the difference between singular point and singular mechanism is explained. A Simple example shows that singular point is local but singular mechanism is global. In other words the latter singularity is globally maintained. Secondly, four characteristics are introduced. The first one is gravity equilibrium, the second is centroid immobility, the third is conservation of angular momentum and the last is constant posture. Gravity compensation is made possible by gravity equilibrium, and no reaction is made possible by centroid immobility and conservation of angular momentum. Thirdly, a robot arm using a singular mechanism is introduced, and characteristics of no reaction are shown by a computer simulation. Finally, it shows the motion range of the arm as an issue.