High accuracy, zero backlash rotary-to-linear electromechanical actuator

An electromechanical actuator, comprising:

• a brushless DC electric motor adapted to be selectively energized and configured, upon being energized to generate a drive torque;
• a harmonic drive gear train coupled to receive the drive torque from the motor and, upon receipt thereof, supply a reduced-speed drive torque;
• a cable yoke coupled to receive the reduced-speed drive torque from the harmonic drive gear train and configured, upon receipt thereof, to rotate about a rotational axis;
• an output shaft coupled to receive a drive force and configured, upon receipt thereof, to translate along a linear axis that is disposed at least substantially perpendicular to the rotational axis;
• a pair of cables, each cable wound, in pretension, on a portion of the cable yoke and around a portion of the output shaft, the pair of cables configured, upon rotation of the cable yoke, to supply the drive force to the output shaft;
• a position sensor coupled to the output shaft and configured to sense a position of the output shaft and supply a position signal representative thereof;
• and
• a motor control coupled to receive the position signal from the position sensor and configured to commutate the brushless DC motor using the position signal.

A valve control system, comprising:

• a valve coupled to receive a translational drive force and operable, upon receipt thereof, to selectively move, along a linear axis, between a closed position and a plurality of open positions;
• and
• an actuator coupled to the valve and configured to supply the translational drive force thereto, the actuator comprising:
• an electric motor adapted to be selectively energized and configured, upon being energized to generate a drive torque;
• a cable yoke coupled to receive the drive torque and configured, upon receipt thereof, to rotate about a rotational axis;
• an output shaft coupled to receive a drive force and configured, upon receipt thereof, to translate along the linear axis, the linear axis being disposed at least substantially perpendicular to the rotational axis;
• and
• a pair of cables, each cable wound, in pretension, on a portion of the cable yoke and around a portion of the output shaft, the pair of cables configured, upon rotation of the cable yoke, to supply the drive force to the output shaft.