Water level control for a non-minimum phase hydraulically balanced beam system

A multivariable nonlinear hydraulically balanced beam system with unstable internal dynamics is considered. Due to the complexity and uncertainty of system model, the control design with exact feedback linearization may not be very practical. Alternatively its equilibrium manifold is incorporated into the control design to stabilize the internal dynamics and to cancel system nonlinearity. On-line adaptation of equilibrium manifold parameters is introduced to reduce the modeling error. Due to the actuator capacity, motion from an equilibrium point to another has to be accomplished by trajectory following along the equilibrium manifold.