Patent ID: 6013995
Filing Date: 2000-01-11
Classification: G11B

Abstract:
A servo control apparatus utilizing adaptive feedforward control, said apparatus comprising:a velocity command device adapted to receive a position indicating signal and to generate therefrom a velocity command signal;a velocity error signal generator in communication with said velocity command device and adapted to receive said velocity command signal and a velocity indicating signal and to generate therefrom a velocity error signal;a gain function device in communication with said velocity error signal generator and adapted to receive said velocity error signal and one or more plant state variable signals and to generate therefrom a current command signal, with each one of said one or more plant state variable signals representative of a value of a plant state variable of a plant undergoing servo control by said apparatus;a current control signal generator in communication with said gain function device and adapted to receive said current command signal and an adaptive feedforward signal and to generate therefrom a current control signal for control of said plant;an adaptive feedforward device in communication with said velocity command device and said current control signal generator and adapted to receive said velocity command signal and to generate therefrom said adaptive feedforward signal, with said adaptive feedforward device including a feedforward calculator and a low pass filter and with said low pass filter adapted to substantially prevent high frequency signal components from arising in said current control signal; andsaid low pass filter providing said adaptive feedforward signal having the following characteristic: ##EQU4## where .alpha.: low pass filter coefficient J: actuator inertia,K.sub.T : torque coefficient,A.sub.rml : arm length,V.sub.max : maximum velocity of a motorI.sub.max : maximum current supplied to a motor,.DELTA.t: servo sampling interval, and.DELTA.V: velocity command (n)-velocity command (n-1).