Mu control of aircraft in windshear

Using H-Infinity/μ control analysis and synthesis methods, a first-order controller is derived for aircraft flight through moderate to severe windshear. It satisfies robust performance as well as robust stability requirements for a constructed linearized uncertain system containing two repeated scalar uncertainties due to changes in dynamic pressure and angle of attack. Results of applying the derived μ controllers are given for the severe windshear models in W.J. Grantham (1990) and Y. Zhao and A.E. Bryson, Jr. (1990). The input to the controller is the tracking error between a commanded windshear-free nominal airspeed value and the actual windshear-free airspeed during flight through windshear. Controlling this error leads to robust performance against moderate to severe windshear. The results illustrate the significance of keeping the windshear-free airspeed near its nominal windshear-free value. Decreasing it before controlling the aircraft against windshear leads to unnecessary loss in altitude as flight progresses through windshear