Version 1.0, August 31, 2001, Copyright, Hugh Jack 1993-2001
· When a system has a disturbance that can be measured we can add a controller that specifically compensates.
· The figure below shows a feedforward disturbance controller,
· In this case `F(B)' is a function of how the disturbance actually effects the system. But `Gf' is the controller to compensate. First, we need a model of `F(B)'. Next the controller `Gf' is,
· The error controller is designed as if the disturbance is not present.
· This system is well suited to systems with large measurable disturbances. For example we could measure cutting force, and adapt an axis controller on a CNC machine.