Nonlinear Controller Design for a Nonlinear helicopter model

A nonlinear controller is going to be designed for a nonlinear helicopter model. Model (plant) has 4 inputs, 9 states and 12 outputs. Any controller may going to be okay for me, but it should be a nonlinear controller. I mean I don't want a LQR controller or PID controller. Please contact me with a controller design method you want. I'm going to share detailed files for the system. Note: Nonlinear model can be trimmed and linearized around specific flight condition. So, you are going to have both linear and nonlinear system. You can design controller using A,B,C,D matrices for the linear system and try with the nonlinear system, if you want. Note 2: Control aim is to follow the trajectory (position tracking) or velocity/attitude tracking. *States are longitudinal velocities (u, v, w), rotational velocities (p, q, r) and Euler angles (phi, theta, psi) *Outputs are longitudinal velocities (u, v, w), rotational velocities (p, q, r), Euler angles (phi, theta, psi) and positions (X, Y, Altitude) *Inputs are longitudinal cyclic, lateral cyclic, collective and pedal. Note 3: Software should be in Matlab/Simulink. Note 4: Detailed information about controller should be given. If it can be a design report, it's the best for me.