Reaction balanced rotary drive mechanism

摘要

A rotary drive mechanism is disclosed comprising a housing, a first motor having a first rotor and a first stator connected to the housing and a second motor having a second rotor and a second stator connected to the housing characterised in that the second motor is mechanically independent of the first motor whereby acceleration torques of the first motor are at least partially inertia balanced by the second motor. The balancing may be effected by equal and opposite rotation of the second motor. Control means may be provided to provide the second motor with a current which is proportional to that supplied to the first motor. Also disclosed is a positioning device and a probe having the rotary drive mechanism.