1. A system for controlling a plant to a reference set point comprising: an outer-loop controller receiving said reference set point and a performance variable value from said plant, said outer-loop controller generating a desired virtual control input; an inner-loop controller receiving said desired virtual control input from said outer-loop controller and generating a real control input; at least one actuator receiving said real control input from said inner-loop controller and generating an actual virtual control input; wherein said plant receives said actual virtual control input from said at least one actuator and generates an updated performance variable value; said inner-loop controller also minimizing a cost function in real time in order to generate said real control input, said cost function being a function of said desired virtual input and said actual virtual control input; and said at least one actuator provides said plant a disturbance, said disturbance equal to the difference between said actual virtual control input and said desired virtual control input.