1. A method for controlling a multivariable system that includes a gas turbine engine, the method comprising: measuring one or more engine parameters using one or more engine sensors; providing a control system configured with a dynamic inversion algorithm, an optimization algorithm and an on-board model; respectively comparing one or more biased predicted engine parameters from a previous control process cycle to the one or more measured engine parameters to determine model error in the on-board model; generating bias data as a function of model error in the on-board model; updating the dynamic inversion algorithm with one or more model terms generated by the on-board model; generating effector equation data by processing reference value data with the updated dynamic inversion algorithm, which effector equation data is indicative of one or more goal equations and one or more limit equations, and which reference value data is indicative of one or more goal values and one or more limit values and is determined as a function of predicted parameter data; at least partially adjusting at least one of the reference value data and/or predicted parameter data for the model error using the bias data; generating one or more effector signals by processing the effector equation data with the optimization algorithm; and controlling operation of the gas turbine engine by providing the one or more effector signals to corresponding engine actuators.