US Patent 8092398 Multi-axis tilt estimation and fall remediation

Among other things, a vestibular prosthesis includes a wearable motion sensing system, the motion sensing system generating a motion signal indicative of a motion thereof, wherein the motion includes rotation about two distinct axes; a signal processor in communication with the motion sensing system, the signal processor being configured to generate an estimate of a tilt of the motion sensing system; and an actuator responsive to the estimate of the tilt made by the signal processor.