Compensation of compliance errors in parallel manipulators composed of   non-perfect kinematic chains
  The paper is devoted to the compliance errors compensation for parallel manipulators under external loading. Proposed approach is based on the non-linear stiffness modeling and reduces to a proper adjusting of a target trajectory. In contrast to previous works, in addition to compliance errors caused by machining forces, the problem of assembling errors caused by inaccuracy in the kinematic chains is considered. The advantages and practical significance of the proposed approach are illustrated by examples that deal with groove milling with Orthoglide manipulator. 
Alexandr Klimchik (IRCCyN), Anatoly Pashkevich (IRCCyN), Damien   Chablat (IRCCyN), Geir Hovland
cs.RO