Calibration of Reconfigurable Stewart-Gough Platform for Mobile Machining Application

Abstract

This paper considers the problem of calibrating a reconfigurable Stewart-Gough platform for mobile machining applications using partial information measurements. The motivation for the work comes from the wind turbine industry, where cost reduction for machining of large components is desired. In the paper kinematic description of an actual prototype machine, together with description of partial information calibration methods of which simulated and experimental results are shown. Results of the proposed calibration methods, where only positional data of the machine was measured by a laser tracker, showed great improvement of the machine performance. Results from experiments showed achievable positioning tolerances of maximum 65μm after an initial factory calibration, and 146μm for a secondary calibration, where fewer parameters were included to reduce lost machining time during configuration change. Machining tests furthermore indicated that it is possible to continue machining across different configurations.