Abstract: A double-ball bar (DBB) based approach for kinematic calibration of a novel 3 DOF spindle head named A3 head is presented. The error model is formulated by projecting the loop closure equations onto in the directions of actuation and constraints of each limb, allowing the geometric source errors affecting the compensatable and uncompensatable pose accuracy to be separated. A two-step kinematic calibration algorithm is then carried out, i.e. firstly to identify the relative and absolute home errors of each limb by using a diameter and cylindrical gauge, and then to identify the rest source errors by using a DBB. The effectiveness of this approach is verified by both computational and experimental results.

Key words: 3-DOF spindle head, Double-ball bar, Kinematic calibration, Boiler, Modeling, Tube Rupture, Leakage, Power Plant