1. A control system comprising: an actuator for positioning a control surface, the control surface comprising a vane or nozzle surface positioned to control a boundary condition of a working fluid flow; a control law for controlling the actuator, and a processor for generating an output vector to direct the control law, the processor comprising: an open loop module for generating the output vector as a function of a state vector and an input vector, wherein the input vector describes the boundary condition of the working fluid flow; a corrector for generating a corrector vector as a function of the output vector; a comparator for generating an error vector by comparing the corrector vector to the input vector; and an estimator for generating the state vector as a function of a multiple-input, multiple-output gain tensor that operates to decouple cross-correlated elements of the error vector and the state vector, such that the error vector is minimized; wherein the state vector describes a spool speed and the processor has a cycle time of 50 ms or less, such that the state vector has a response time slower than the cycle time.