Torque disturbance rejection improvement by voltage mode control using current driver

This paper introduces an alternative method of voltage based actuator control providing a driver for DC motor or Voice Coil Motor (VCM) with current source and local voltage feedback by activating the back electromotive voltage. The existing method also proposed by the author provides a voltage source and a local current feedback reducing the VCM impedance in appearance in order to suppress the torque disturbances such as nonlinear friction of pivot bearing, flexible cable tension, and spinning disk windage. This method allows servo controller designers to choose either of a voltage source or a current source for the driver in order to target sub-nano meter positioning accuracy.