Singularity Closeness of Stewart-Gough Platforms (Differential Geometry)

Agency: FWF (P30855)
Dates: 2018 – 2022
Project leader: Georg Nawratil


General information:

This project is devoted to the evaluation of singularity closeness of Stewart-Gough (SG) platforms. To recall, a parallel manipulator of SG type consists of a moving platform, which is connected via spherical-prismatic-spherical legs with the base, where only the prismatic joints are active. The number of applications of SG manipulators, ranging from medical surgery to astronomy, has increased enormously during the last decades due to their advantages of high speed, stiffness, accuracy, load/weight ratio, etc. One of the drawbacks of these parallel robots are their singular configurations, where the manipulator is shaky while all leg lengths are fixed. As a consequence the actuator forces can become very large, which may result in a breakdown of the mechanism. Therefore singularities have to be avoided. This reasons the high interest of the kinematic/robotic community in evaluating the singularity closeness of SG platforms, but geometric meaningful distance measures for this task are still missing. The research project closes this gap.


Fig.: A linear pentapod in the given (green) configuration and the closest singular configuration (red). The yellow configuration is the closest singularity under affine motions.

Singularity Closeness of Stewart-Gough Platforms (Differential Geometry)