2004 Volume 47 Issue 1 Pages 160-167
This paper presents a methodology to compensate contouring errors introduced by the gravity on a Hexapod-type parallel kinematic machine tool with the Stewart platform. Unlike conventional serial kinematic feed drives, the gravity imposes a critical effect on the positioning accuracy of a parallel kinematic feed drive, and its effect significantly varies depending on the position and the orientation of the spindle. We first present a kinematic model to predict the elastic deformation of struts caused by the gravity. The positioning error at the tool tip is given as the superposition of the deformation of each strut. It is experimentally verified for a commercial parallel kinematic machine tool that the machine's contouring error is significantly reduced by compensating gravity-induced errors on a reference trajectory.
JSME international journal. Ser. 1, Solid mechanics, strength of materials
JSME international journal. Ser. A, Mechanics and material engineering
JSME international journal. Ser. 3, Vibration, control engineering, engineering for industry
JSME international journal. Ser. C, Dynamics, control, robotics, design and manufacturing
JSME International Journal Series A Solid Mechanics and Material Engineering
JSME International Journal Series B Fluids and Thermal Engineering