Kinematics of a Novel Type Positioning Table for Cast Alignment on Machine Tool

The paper presents a study into the kinematics of a novel type of a rotary positioning table based on the constrained parallel mechanism. Fixture and leveling a workpiece on a machine tool table is an essential stage in machining or layout process. In this study, a compact low-height rotary table is presented for automated leveling, which can be mounted directly on the machine tool table without a significant decrease of the workspace. The authors propose a modification of parallel mechanism by introducing four extensible leg design with specific geometrical constraint for workpiece positioning and in order to achieve higher rigidness. The table is driven by four hydraulic linear actuators which are integrated in the linkages. The designed model allows to rotate the table about the sphere center about three independent axis. Procedures using meta-heuristic methods were implemented to optimize the geometrical dimensions of the entire mechanism for the required workspace.Copyright © 2015 by ASME