Precision tool holder with flexure-adjustable, three degrees of freedom for a four-axis lathe

An apparatus for controlling the spatial position of an article comprising:

• a first adjustment mechanism having a first base fixed relative to an ijk coordinate system, a first platform, at least two parallel flexure hinges connecting the first platform to the first base to enable and guide movement of the first platform in a direction parallel to the i axis of the ijk coordinate system, and means for actuating the first platform to adjust the i-axis position thereof relative to the first base;
• a second adjustment mechanism having a second base fixed relative to the first platform, a second platform, at least two parallel flexure hinges connecting the second platform to the second base to enable and guide movement of the second platform in a direction parallel to the j axis of the ijk coordinate system, and means for actuating the second platform to adjust the j-axis position thereof relative to the second base;
• and
• a third adjustment mechanism having a third base fixed relative to the second platform, a third platform having means for holding the article thereon, at least one flexure hinge connecting the third platform to the third base to guide movement of a held article in a direction parallel to the k axis of the ijk coordinate system, and means for actuating the third platform to adjust the k-axis position of the held article relative to the third base.