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A comprehensive set of stability, handling qualities, and performance specifications was used to drive the optimization of commonly used fixed-wing longitudinal control laws applied to a business jet. The specifications were divided into two tiers. The first were the key flight control and handling qualities requirements and were used directly for optimization, while the second were used as a check afterwards. Similarities between the commonly used longitudinal control laws investigated in this study and a model following controller were exploited to explicitly set feed-forward gains to provide good handling qualities. A linear-quadratic regulator method was employed for preliminary design as a way to initialize the control law feedback gain values for optimization. A multi-objective parametric optimization approach was then used to arrive at feedback gains that concurrently satisfy all specifications. Using this optimization approach, the trade-offs of increased crossover frequency were investigated. In addition, a smooth gain schedule was generated by optimizing the control law parameters of different flight conditions to meet the same requirements. This paper describes the control law architecture used as well as the optimization approach, the specifications used, and the design results. Nomenclature α Angle-of-attack [deg, rad] α cmd Angle-of-attack command [rad] α nz Steady state angle-of-attack per normal load factor [rad/g] q Dynamic pressure [psf] δ act Actuator position [deg] δ stk Stick force [lb] α Angle-of-attack rate [deg/sec, rad/sec] α cmd Angle-of-attack rate command [rad/sec] δ act Actuator rate [deg/sec] n z cmd Commanded normal load factor rate [g/sec] q Pitch acceleration [rad/sec 2 ] ω c Crossover frequency [rad/sec] ω n Natural frequency [rad/sec] ω α LQR output shaping function frequency of complex-pair target zeros [rad/sec] ω cmd Command model frequency [rad/sec] ω inv Inverse model frequency [rad/sec] ω sp Short-period frequency [rad/sec] φ Bank angle [rad] τ Time delay [sec] τ n Normal acceleration transfer function equivalent time delay [sec] τ q Pitch rate transfer function equivalent time delay [sec] τ cmd Command time delay [sec] θ Pitch attitude [deg, rad] θ DB Pitch attitude dropback [deg] ζ Damping ratio [-] ζ α LQR output shaping function damping of complex-pair target zeros [-] ζ cmd Command model damping [-] ζ inv Inverse model damping [-] ζ sp Short-period damping [-] a LQR output shaping function real zero [rad/sec] g Acceleration due to gravity [ft/sec 2 ] J LOES LOES fit cost J M F Model following cost K Control law gain K n Normal acceleration transfer function gain [g/deg-elev] K q Pitch rate transfer function gain [rad/sec/deg-elev] K stk Stick gain [g/lb] K u Speed error gain [g/kt] M α Dimensional pitch stiffness derivative [1/sec] M δe Dimensional pitch rate control derivative [rad/sec 2 /deg − elev] n/α Steady-state normal acceleration change per unit change of angle-of-attack [g/rad] n z Normal acceleration [g] n z Normal load factor at the ICR [g] n z u, n z +u No...

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This paper presents the development and piloted assessment of a full flight-envelope simulation model of a light business jet using a model stitching architecture. Individual state-space models and trim data for discrete flight conditions were combined to produce a continuous simulation model, which was integrated into a fixed-base simulation facility. Back-to-back flight/simulation piloted evaluations of a similar light business jet in flight and the stitched model in simulation were performed to assess the fidelity of the stitched model. Overall pilot impressions were that the stitched simulation model was representative of the actual aircraft. Simulation Fidelity Ratings were given to quantify simulation fidelity for each of the evaluated qualitative tasks, in which mostly Fidelity Level 1 ratings were assigned, suggesting full transfer of training for those tasks. Guidance on flight testing for the development of fixed-wing aircraft stitched models is provided.