Direct Kinematic Singularity Detection of a Hexa Parallel Robot

Abstract

Besides a quantity of well-known positive characteristics, parallel robots also obtain a couple of negative properties which limit their efficient use in certain application areas nowadays. Direct kinematic singularities that constrain the internal workspace are one of these inconvenient properties. This paper establishes a unique index, with physical meaning, that indicates the entrance of the Hexa parallel robot, considering its joint limits, to all its direct kinematic singularities. For this, we complement two methods to detect singularities: the power inspired measure method and the Grassmann geometry method. The applied procedure uses screw theory and line geometry tools to represent movements, actions and lines, respectively, in the robot. This procedure is practically verified in Hexa robot and shows that some singularities are overlapped forming large singularities.