Designing a reference model that produces trajectories reflecting capabilities of the aircraft is crucial for control system design. Fundamentally, it offers two advantages. First, it prevents integrator windup when there is an integral action in the controller. Second, it mitigates actuator saturation and reduces the effect of unachievable commands on other axes, in the case of multiaxis effectors like propellers in a multi-rotor aircraft. Pseudo control hedging (PCH) provides a feedback of the unachieved pseudo controls to the reference model, in order to slow down reference trajectories. Typically, implementation of PCH alters the closed-loop response of the system, since it accounts for not only actuator nonlinearities like saturations, but also the linear dynamics of the actuators. Moreover, in feedforward-feedback control structures, the effect of hedging is not visible in the pseudo control command unless reference model is significantly slower than the controller. In this paper, we propose a PCH structure that is active only in the case of actuator saturations and therefore, does not alter the nominal closed-loop response and does not require the reference model to be slower than the controller. Additionally, we propose a reference model architecture with a novel PCH implementation for a transition aircraft employing a unified control strategy.

