Sony Corporation

Masaomi Inagaki

Takashi Nakatsuyama

Tsunehiro Maruo

Hiroshi Teranishi

A position control system for controlling a motor-driven mechanism capable of occupying a plurality of specified positions comprises a plurality of switches for specifying a position to be occupied by the mechanism and an encoder for generating a specified position signal representative of the specified position and a loading circuit for providing a present position signal representative of the position presently occupied by the mechanism. A read-only memory circuit uses the specified and present position signals to provide a control signal for controlling the motor to move the mechanism to a particular position and a comparison signal and a particular position signal indicative of that particular position. A position detector responsive to the position of the mechanism provides a detection signal representative of the particular position when the mechanism reaches it. A comparator compares the comparison signal from the memory circuit with the detection signal and provides a match signal to the loading circuit when they coincide. In response to the match signal the loading circuit loads the particular position signal into the memory circuit as the present position signal. If the particular position signal matches the specified position signal, the memory circuit provides a control signal that stops the motor. If the particular position does not match the specified position signal, the memory circuit provides a control signal to actuate the motor again. The illustrated embodiment of the system provides a tape recording and reproducing apparatus with four different operating modes.

Position control system

Apparatus for generating a signal corresponding to a reference phase of a reference rotor of a motor relative to the stator, includes a field magnet having a plurality of north and south poles mounted on the rotor; a Hall-effect element associated with the field magnet and mounted on the stator for generating a position signal corresponding to the position of the rotor relative to the stator for use in changing-over energization of coils on the stator; a plurality of equally spaced cut-out portions along the periphery of the rotor forming a plurality of equally spaced toothed portions; an optical detector associated with the toothed portions and mounted on the stator for generating a speed signal corresponding to the rotational speed of the rotor relative to the stator; a differentiating circuit for differentiating the position signal to produce a differentiated signal; and an AND gate supplied with the differentiated signal and the speed signal for producing the phase signal corresponding to a reference phase of the rotor relative to the stator.

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Yachiyo, Japan

Masaomi Inagaki