Abstract
Most severe pilot-induced oscillations (PIOs) are characterized as the presence of actuator rate limiting. Rate limiting causes phase lag and magnitude reduction between the limiter input and output when the input signal rate exceeds the rate limitation. This is the main cause of PIOs. Herein, two controllers, in which actuator rate limiting is redefined as input constraints, are designed based on the model predictive control (MPC) strategy and applied to the pilot-aircraft loop in both parallel and serial manners. In the parallel implementation, the MPC controller can suppress rate-limiter-based PIOs. In the serial implementation, the MPC controller can compensate the phase lag due to rate limiting, and hence, help the pilot prevent PIOs from occurring in advance.
