Flexure pivot for aerospace mechanisms

A generic high precision flexible pivot dedicated to pointing and scanning space mechanisms is described. Typical applications are payload scientific instruments and inter-satellite communication systems. The work started with a comprehensive analysis of the present and future market and mission needs. This survey was used to define requirements for a baseline pivot concept in terms of mobile mass, inertias, size, angular strokes, etc. A comprehensive solution catalogue was established and traded-off to select an original concept. This concept was designed in detail and manufactured by wire electro-discharge machining for characterization on special test benches. The main characteristic of the proposed design is its very small parasitic center translation : less than 2 μm off axis shift over a ±10° motion range (which is 65 times less than a classical cross spring pivot of the same size). Resolution better than 50 μrad was achieved over a ± 10° stroke. Fatigue tests show that the pivots can endure more than 1.4 million cycles of ± 7.5° stroke without failure.