ORION MINANGLE: A FLEXURE-BASED, DOUBLE-TILTING PARALLEL KINEMATICS FOR ULTRA-HIGH PRECISION APPLICATIONS REQUIRING HIGH ANGLES OF ROTATION

If you need to design ultra-high precision devices1 for mechanisms with multiple axes there are not a lot of ways leading around flexure-based joints. Using this type of articulations totally eliminates backlash and friction and is, by this, providing an accurate mechanical foundation for your device. The most important disadvantage of this technology is the low range of motion. The basic joint types, blades and circular hinges, have angular limits which strongly depend on the targeted stiffness, the quan-tity of motion cycles and the elastic limit of the material. This article will introduce novel parallel kinematics which are totally based on 1 dof 2 flexures and whose angu-lar range of motion is determined by twice the range of the single joint. It is a 3 dof parallel kinematics based on 3 identical kinematic chains which produces move-ments in θx, θy and Z. The model has been designed to constitute the left hand of a machine tool that requires to orient the workpiece in a very precise manner and with high rotation amplitudes. Additionally to this it pre-sents very interesting characteristics of Remote-Center-of-Motion (RCM) mechanisms. This is a vital feature for applications where the linear movements are highly limited and should not be consumed by parasitic move-ments of other axes. All these features, combined with the advantages of parallel kinematics, makes the Orion Mi-nAngle a very interesting concept. The model has been designed with joints achieving ±8◦ leading to an output angle of ±15 ◦ on both rotation axes. 1