Browsing by Author "Kolmanovsky, Ilya"

Now showing 1 - 3 of 3

Open Access
Adaptive control allocation for over-actuated systems with actuator saturation
(Elsevier B.V., 2017) Tohidi, Seyed Shahabaldin; Yıldız, Yıldıray; Kolmanovsky, Ilya
This paper proposes an adaptive control allocation approach for over-actuated systems with actuator saturation. The methodology can tolerate actuator loss of effectiveness without utilizing the control input matrix estimation, eliminating the need for persistence of excitation. Closed loop reference model adaptive controller is used for identifying adaptive parameters, which provides improved performance without introducing undesired oscillations. The modular design of the proposed control allocation method improves the flexibility to develop the outer loop controller and the control allocation strategy separately. The ADMIRE model is used as an over-actuated system, to demonstrate the effectiveness of the proposed method using simulation results.
Open Access
Pilot induced oscillation mitigation for unmanned aircraft systems: an adaptive control allocation approach
(Institute of Electrical and Electronics Engineers, 2018) Tohidi, Seyed Shahabaldin; Yıldız, Yıldıray; Kolmanovsky, Ilya
This paper proposes an adaptive control allocation method that can make unmanned aircraft systems recover from pilot induced oscillations. Pilot induced oscillations are undesired oscillations due to an unintentional and detrimental coupling between the aircraft and the pilot. These oscillations may be instigated due to disturbances, aggressive maneuvers and actuator saturation. Different from manned aircraft, pilot induced oscillations in unmanned aircraft systems are harder to handle due to communication time delays between the operator and the aircraft. The task of a conventional control allocator is to distribute the control effort among redundant actuators to realize a desired virtual control input. When actuators rate saturate, the difference between the desired and the achieved virtual control input introduces an effective time delay to the system dynamics which causes oscillations. In the proposed approach, instead of minimizing the error between the desired and achieved virtual control inputs, the derivative of this error is minimized which eliminates the introduced time delay effect and damps undesired oscillations. Differently from earlier works conducted by the authors, in this work, the proposed pilot induced oscillation mitigation methodology is developed for systems with parametric uncertainty. In the simulations, it is demonstrated that the proposed approach successfully damps pilot induced oscillations that are instigated by a high gain pilot command.
Open Access
Time-varying sliding mode controller for over-actuated systems with constrained and uncertain actuators in flightcontrol applications
(John Wiley and Sons, Ltd, 2022-10-29) Yildiray, Yildiz; Kolmanovsky, Ilya; Tohidi, Seyed Shahabaldin
One solution to the problem of distributing the control action among redundant actuators with uncertain dynamics is employing an adaptive control allocator. This paper proposes a sliding mode controller which exploits a time-varying sliding surface to complement adaptive control allocation in the presence of actuator saturation. The proposed approach does not require error augmentation for tracking desired references, which diminishes the computational burden. Aerodata Model in Research Environment, which is an over-actuated aircraft model, is adopted to demonstrate the efficacy of the proposed controller in simulation studies.