Electrically controlled camera positioning system

A camera positioning system for rotating a video camera about a rotation axis, comprising:

• a camera platform to which said camera is fixedly attached for axial rotation about said axis,
• a motor mounted to a base, said motor for driving said camera platform to effect rotation of said platform about said axis and relative to said base,
• a friction drive for coupling said motor to said camera platform to effect rotation of said platform about said rotation axis, said friction drive comprising a friction drive surface coupled to a friction driven surface, said drive surface being rotatably attached to an output shaft of said motor and said driven surface being attached to said camera platform for movement therewith,
• an electrically driven capacitive sensor assembly for generating electrical position signals for determining a rotational position of said camera platform relative to said base, said capacitive sensor comprising a rotor and a pickup sensor mounted in a spaced apart overlapping configuration, one of said rotor or pickup sensor being attached to said camera platform and the other of said rotor or pickup sensor being attached to said base, said capacitive sensor further comprising a conductive guard plate spaced from said pickup sensor on a side of said pickup sensor opposite to that of said rotor, supported by said base, and which shields said pickup sensor from ground potential and noise, said rotor including a spiral plate pattern having a first conducting surface and a second conducting surface, the rotational position of said camera platform relative to said base being determined by the amount of overlap between said pickup sensor and each of said conducting surfaces, said capacitive sensor assembly further comprises a high impedance, low input voltage measuring capacitance circuit including two discrete field-effect transistors connected between said pickup sensor and an amplifier, said capacitive sensor providing an indication of the absolute rotational position of said camera about said axis and resolution of at least 0.0016 of a degree over 270 degrees, and
• a feedback control circuit for using said position signals from said capacitive sensor assembly to control rotational positioning of said motor, resulting in rotating said camera to a desired camera position.

A camera element positioning system for rotating a rotational camera element about an axis, comprising:

• a motor for driving said rotational camera element to effect rotation of said rotational camera element about said axis,
• a drive for coupling said motor to said rotational camera element to effect rotation of said rotational camera element about said axis,
• an electrically driven capacitive sensor assembly for generating electrical position signals for determining a rotational position of said rotational camera element, and
• a feedback control circuit for using said position signals from said capacitive sensor assembly to control rotational positioning of said motor, resulting in rotating said rotational camera element to a desired position.