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How to Tune a Multivariable Controller

 Learn the step-by-step process for tuning a multivariable controller using an example of a two-loop autopilot that controls the pitch rate and vertical acceleration of an airframe. The airframe dynamics and the autopilot are modeled in Simulink® leveraging its Model-Based Design approach.

The airframe dynamics model is composed of an aerodynamics model, constant thrust input, and equations of motion to provide a complete mathematical model of an aircraft. The autopilot consists of two cascaded loops; the inner loop controls the pitch rate q, and the outer loop controls the vertical acceleration az in response to the pilot stick command vertical acceleration (az) ref. The architecture also includes the tunable elements, the PI controller gains (“az Control” block), and the pitch-rate gain (“q Gain” block). The goal is to tune the autopilot to respond to input vertical acceleration (az ref) with a 1-second response time, with minimal overshoot for a change in az ref for a steady state condition of a straight and level flight with constant velocity. The Control System Tuner app in Simulink was utilized for tuning the controller and the Simulation Data Inspector was utilized for visualizing the system response. For more information, please visit ------------------------------------------------------------------------------------------------

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