An apparatus (100, 200, 300, 400) for controlling a position of a control surface of a vehicle, the apparatus comprising: an error module (190, 230) adapted to calculate a difference between a first state ( ŷ meas)of a vehicle, the first state based on a bounded command ( y cmd), and a second state ( y meas) of the vehicle, the second state based on a measurement from a sensor; an observer module (120, 310, 410) adapted to determine a third state (x̂) of the vehicle based on the difference, wherein the observer module is adapted to determine the third state (x̂) based on (i) determining a sum based on (ii) applying an observer error feedback gain ( L v) to the second state ( y meas) and (iii) a gain command ( B cmd) to the bounded command ( y cmd), (iv) the second state ( y meas)based on an output observation error ( e yI) and a measured vehicle plant output ( y p meas), in which: the output observation error ( e yI) is based on a difference between a regulated output of a baseline control module ( y reg) and the bounded command ( y cmd), wherein the measured plant output ( y p meas), is based on the output of a transfer function of a vehicle plant representing the vehicle, and wherein the observer module is further adapted to execute an observer module transfer function using the sum to generate the third state ( x̂); the baseline control module (130, 320, 420) adapted to generate a first command (û) based on the third state ( x̂); and a vehicle module adapted to execute the first command (û) to control the vehicle by moving the control surface of the vehicle from a first position to a second position. an error module (190, 230) adapted to calculate a difference between a first state ( ŷ meas)of a vehicle, the first state based on a bounded command ( y cmd), and a second state ( y meas) of the vehicle, the second state based on a measurement from a sensor; an observer module (120, 310, 410) adapted to determine a third state (x̂) of the vehicle based on the difference, wherein the observer module is adapted to determine the third state (x̂) based on (i) determining a sum based on (ii) applying an observer error feedback gain ( L v) to the second state ( y meas) and (iii) a gain command ( B cmd) to the bounded command ( y cmd), (iv) the second state ( y meas)based on an output observation error ( e yI) and a measured vehicle plant output ( y p meas), in which: the output observation error ( e yI) is based on a difference between a regulated output of a baseline control module ( y reg) and the bounded command ( y cmd), wherein the measured plant output ( y p meas), is based on the output of a transfer function of a vehicle plant representing the vehicle, and wherein the observer module is further adapted to execute an observer module transfer function using the sum to generate the third state ( x̂); (i) determining a sum based on (ii) applying an observer error feedback gain ( L v) to the second state ( y meas) and (iii) a gain command ( B cmd) to the bounded command ( y cmd), (iv) the second state ( y meas)based on an output observation error ( e yI) and a measured vehicle plant output ( y p meas), in which: the output observation error ( e yI) is based on a difference between a regulated output of a baseline control module ( y reg) and the bounded command ( y cmd), wherein the measured plant output ( y p meas), is based on the output of a transfer function of a vehicle plant representing the vehicle, and wherein the observer module is further adapted to execute an observer module transfer function using the sum to generate the third state ( x̂); the output observation error ( e yI) is based on a difference between a regulated output of a baseline control module ( y reg) and the bounded command ( y cmd), wherein the measured plant output ( y p meas), is based on the output of a transfer function of a vehicle plant representing the vehicle, and wherein the observer module is further adapted to execute an observer module transfer function using the sum to generate the third state ( x̂); the baseline control module (130, 320, 420) adapted to generate a first command (û) based on the third state ( x̂); and a vehicle module adapted to execute the first command (û) to control the vehicle by moving the control surface of the vehicle from a first position to a second position. a vehicle module adapted to execute the first command (û) to control the vehicle by moving the control surface of the vehicle from a first position to a second position.