Sony Corporation

Hajime Yamanaka

Masatsugu Iribe

Shinya Suzuki

Yoshihiro Itoh

A motor comprises: coil on/off switching devices for switching between an on-state wherein current is supplied to the coils, and a first off-state wherein the coil terminals are open-circuited or a second off-state wherein the coil terminals are short-circuited; and a coil current control device for controlling switching operations of the coil on/off switching devices according to commands input to the motor. In the event that motor movement with great mechanical compliance is required, the ratio of the period of the first off-state is increased, and on the other hand, in the event that motor movement with great viscosity resistance is required, the ratio of the period of the second off-state is increased. This solves the problems of torque loss and cogging during a period wherein no current is applied to the coil.

Motor, actuator and controller thereof

To appropriately detect overload which may break a motor or deform a body and reduce the overload in the motor. The DC component of a load torque is derived from the sum of absolute values of a torque applied to a link connected to the output shaft of a motor and the generated torque of the motor, and it is determined that overload has been applied when the DC component exceeds a first threshold value for a prescribed period of time or longer. In addition, considering such a characteristic that the variation of energy applied to the output shaft of a motor is in proportion to a product of the torque and the angular velocity of the motor, the AC component of the load torque is detected based on the variation of energy, and it is predicted that overload will be applied when the AC component exceeds a second threshold value.

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Tokyo, Japan

Hajime Yamanaka