Rotation controller and rotation control method

An electrically controlled mechanical timepiece comprising:

• a mechanical energy source;
• a generator, driven by said mechanical energy source connected via a train wheel, generating an induced power and thus supplying electric energy;
• a rotation controller controlling the rotation period of said generator by applying one of a braking force and an acceleration force on said generator by power supplied from said mechanical energy source, comprising:
• rotation detecting means for generating a rotation signal corresponding to revolutions of said generator;
• target signal generating means for generating a target signal corresponding to target revolutions of said generator;
• phase difference compensating means for detecting a phase difference between a rotation signal output by said rotation detecting means and said target signal output by said target signal generating means, and generating a phase difference compensating signal;
• frequency difference compensating means for detecting a frequency difference between said rotation signal and said target signal, and generating a frequency difference compensating signal;
• a signal capture circuit selectively triggered to capture and retain the current value of said frequency difference compensating signal output from said frequency difference compensating means, and to produce the captured signal as a reference frequency difference output signal and
• brake/acceleration control means controlling one of the braking force and acceleration force in accordance with the frequency difference compensating signal from said frequency difference compensating means in a first mode of operation, and in accordance with the sum of said reference frequency difference output signal and said phase difference compensating signal during a second mode of operation, wherein said signal capture circuit is triggered in response to a transition from said first mode of operation to said second mode of operation;
• and
• a pointer connected to said train wheel.

A rotation control method for controlling the rotation period of a rotary member by one of braking and accelerating the rotary member rotated by power supplied by a power source, comprising the steps of:

• detecting a phase difference by comparing a rotation signal corresponding to revolutions of the rotary member and a target signal corresponding to target revolutions of the rotary member;
• producing a phase difference compensating signal corresponding to said phase difference
• detecting a frequency difference between said rotation signal and said target signal;
• producing a frequency difference compensating signal corresponding to said frequency difference;
• controlling one of braking and acceleration of said rotary member by means of said frequency difference compensating signal in a first mode of operation, and by means of a sum signal of said phase difference compensating signal and a constant frequency-difference reference signal during a second mode of operation.

A rotation controller controlling the rotation period of a rotary member, comprising:

• a rotation detector to generate a rotation signal corresponding to revolutions of the rotary member;
• a target signal generator to generate a target signal corresponding to target revolutions of the rotary member;
• a phase difference compensator to detect a phase difference between said rotation signal and said target signal, and generating a phase difference compensating signal in response to the detected phase difference;
• a frequency difference compensator to detect a frequency difference between said rotation signal and said target signal, and generating a frequency difference compensating signal in response to the detected frequency difference;
• a signal-capture-circuit to selectively capture and hold the signal value of said frequency difference compensating signal in response to a transition from a first mode of operation to a second mode of operation, the captured signal being output as a constant-offset compensation signal;
• a brake/acceleration controller controlling one of the braking force and acceleration force in accordance with said frequency difference compensating signal during said first mode of operation and in accordance with a sum signal of said constant-offset compensation signal and said phase difference compensating signal during said second mode of operation.

An electrically controlled mechanical timepiece comprising:

• a mechanical energy source;
• a generator, driven by said mechanical energy source connected via a train wheel, generating an induced power and thus supplying electric energy;
• a rotation controller controlling the rotation period of said generator by applying one of a braking force and an acceleration force on said generator by power supplied from said mechanical energy source, comprising:
• a rotation detector to generate a rotation signal corresponding to revolutions of said generator;
• a target signal generator to generate a target signal corresponding to target revolutions of said generator;
• a phase difference compensator to detect a phase difference between said rotation signal and said target signal, and generating a phase difference compensating signal;
• a frequency difference compensator to detect a frequency difference between said rotation signal and said target signal, and generating a frequency difference compensating signal;
• and
• a brake/acceleration controller controlling one of the braking force and acceleration force in accordance with said frequency difference compensating signal during a first mode of operation and a sum signal of said phase difference compensating signal and a constant-offset compensation signal during a second mode of operation;
• and
• a pointer connected to said train wheel.