Feedforward/Feedback Controls in a Noisy Environment

A nonlinear controller useful in situations is presented, in which variable external disturbances are measured with a high-quality sensor. In many applications, feedforward and feedback control are employed in a complementary manner to produce satisfactory response. The feedforward link "cancels" the primary disturbances, and the feedback regulator is then used to minimize any residual errors. The influence of the feedforward signal becomes more subtle when the sensor measuring the disturbance is contaminated with noise.