Abstract
The possibility of a hydrostatically supported spindle having small radial runout not exceeding 0.01μm is examined. The new mechanism compensating the radial motion error is proposed. The mechanism consists of two micropositioning devices called closed looped differential hydrostatic actuator, and their operating directions are at right angle each other. The micropositioning device, having a stiffness of the order of 104N/μm, controls the radial motion of a spindle within 0.001μm. The experimentation shows that the resolution is within 0.001μm, the bandwidth of the control system is about 90Hz, and the interference between the two positioning devices is negligible small. The radial motion error may be compensated by the proposed mechanism.
