Tethered, levitated-mass accelerometer

A multi-axis force-balance accelerometer including 3 rectilinear reference axes X, Y and Z and 3 angular reference axes θ, Φ, and Ψ, the accelerometer comprising:

• a) an enclosure having a null position in each of said 3 rectilinear reference axes and in each of said 3 angular reference axes,
• b) a proof mass included inside said enclosure and movable relative to each of said 3 rectilinear reference axes and each of said 3 angular reference axes,
• c) at least one electrically conductive tether which is flexible in 6 degrees of freedom constituting an electrically conductive link between said proof mass and said enclosure, and
• d) mechanical stops for limiting a range of motion of said proof mass from said null position,
• said enclosure including a plurality of capacitive plates for sensing the position of said proof mass relative to the null position in each of said 3 rectilinear reference axes and in each of said 3 angular reference axes and for applying electrostatic forces on said proof mass along each of said 3 rectilinear reference axes and for applying electrostatic torques on said proof mass around each of said 3 angular reference axes,
• said accelerometer including 3 force balancing control loops for positioning said proof mass in said null position for each of said 3 rectilinear reference axes, and 3 force balancing control loops for positioning said proof mass in said null position for each of said 3 angular reference axes,
• and wherein said electrically conductive tether is mechanically compliant such that, on deactivation of said force balancing control loops for said 3 rectilinear reference axes, said proof mass falls so as to rest on said mechanical stops.