Device for measuring angular errors in the inclination of the true axis of rotation of a rotary element, and associated method

A device (100) for measuring and estimating angular errors of inclination αx(θ), αy(θ) of a real axis of rotation (204) of a rotary element (101) in relation to a reference axis (203), the rotary element (101) being installed in metrology or machining equipment in such a way that its real axis of rotation (204) is aligned as closely as possible with the reference axis (203), the real axis of rotation (204), in relation to the reference axis (203), having an inclination that is variable as a function of the angular position θ of the rotary element about its real axis of rotation (204) or “wobble”, the device including:

• control electronics (111) for controlling the rotation of the rotary element (101) about its real axis of rotation (204);
• a first and a second rotation sensors (112a, 112b) for obtaining respectively angular velocities of the rotary element (101), about two measurement axes (302, 402) which are orthogonal to one another and both orthogonal to the real axis of rotation (204);
• a third rotation sensor (112c) for obtaining the angular position and the angular velocity of the rotary element (101) about its real axis of rotation (204),
• at least two of the above-mentioned sensors being inertial and enabling to obtain projections of the Earth's rotational velocity vector onto at least two projection axes;
• an acquisition unit (113) configured to acquire measurements made by the above-mentioned sensors while the rotary element carries out at least one series of periodic oscillations resulting in reversals of the direction of rotation of the rotary element;
• a memory (114) for storing the measurements of the above-mentioned sensors;
• a calculation unit (115) configured to calculate, from the angular velocities and positions obtained from the above-mentioned sensors, the angular errors of inclination αx(θ), αy(θ) of the real axis of rotation (204) of the rotary element (101) in relation to the reference axis (203)
• and as a function of the angular position θ of the rotary element (101) about its real axis of rotation (204).