Trim Tab Flight Stabilisation System Performance Assessment under Degraded Actuator Speeds

One of the areas involved in changing current aircraft into more electric ones is decreasing energy consumption by the aircraft's automatic flight control. Therefore, some aircraft types have tested the possibility of controlling the flight in automatic mode or stabilising the flight with trimmers. Previous research on cost-effective and less electrical-energy-consuming automatic stabilisation systems for an aircraft resulted in constructing a laboratory model of the system. Such a feature is beneficial for initiatives like Future Sky, electric aircraft and aircraft stabilisation system retrofits. The system was developed using model-based design and next tuned and tested in model, pilot and hardware-in-the-loop simulations. The implementation of this system does not modify the pilot's primary manual controls. Instead, the electrical trim system is used for automatic stabilisation or manual trimming, depending on the chosen operation mode. The paper presents the development process of the laboratory model of the system and its simulation under degraded actuator speeds. The results were the basis for its control performance assessment. First, the control performance measure was defined. Then the simulation scenarios that compare system behaviour in stabilisation mode after aerodynamic disturbance with three different trim tab actuator speeds were described. The performance measure is highly degraded by the slower actuator speeds, although altitude and heading are finally stabilised in all cases. Moreover, the performance of stabilisation in a lateral channel is less affected by the slowest actuator than in a longitudinal channel.