Servo actuator and position sensor
AssigneeSony Corporation
InventorShinji Ishii
Life of this patent
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Abstract
In an actuator having an integrated drive circuit, a switching current flowing in a coil within the actuator is included in a position sensor signal of the actuator. According to the present invention, by arranging a detection circuit which performs sampling in synchronization with noise, a rotational position which does not include higher harmonic waves can be detected even if the switching noise in a motor coil current in the actuator itself is generated. Consequently, elimination of the influence of the noise allows posture and position control with less vibration to be realized.
Claims12
A servo actuator of a type having a permanent magnet at a rotor and a coil at a stator for generating torque by a magnetic flux distribution and a current passing through the coil, the servo actuator comprising:
- a casing that accommodates the rotor and the stator and supports the rotor rotatably around a predetermined rotation axis;
- a drive control unit for controlling the rotation of the rotor by performing PWM (pulse width modulation) switching control on the current passing through the stator coil with a predetermined period;
- a rotational position detection unit for detecting the rotational position of the rotor;
- and
- a sampling control unit for sampling an output of the rotational position detection unit in synchronization with a switching period of the current passing through the stator coil, in the drive control unit.
A position detector for a servo actuator of a type having a permanent magnet at a rotor and a coil at a stator for generating torque by a magnetic flux distribution and a current passing through the coil, the position detector comprising:
- a drive control unit for controlling the rotation of the rotor by performing PWM (pulse width modulation) switching control on the current passing through the stator coil with a predetermined period;
- a rotational position detection unit for detecting the rotational position of the rotor;
- and
- a sampling control unit for sampling an output of the rotational position detection unit in synchronization with a switching period of the current passing through the stator coil, in the drive control unit.
Dependencies are inferred from the claim text.