Integral Sliding Mode based Model Reference FTC of an Over-Actuated Hybrid UAV using Online Control Allocation

Prochazka, Karl Frederik; Stomberg, Gösta

doi:10.23919/acc45564.2020.9147655

Cited by 7 publications

(7 citation statements)

References 16 publications

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“…In [ 27 ], supertwisting SMC was used to mitigate the impact of disturbances and model uncertainty on quadplane trajectory following. In [ 28 ], integral sliding mode control was used to ensure fault tolerant control in an overactuated UAV, with a hardware-in-the-loop (HIL) validation. Other approaches use observer-based controllers as previously described in [ 5 , 6 , 11 , 14 ].…”

Section: Introductionmentioning

confidence: 99%

“…Given the winds handling weaknesses of quadplanes and the importance of fault tolerance for safety and legislation considerations, an unknown input observer approach is developed to ensure accurate quadplane path following under both winds and actuator faults. The quadplane model under consideration is based on the Aerosonde twin boom design, which is popular in the research literature (see [ 28 , 38 ]) and employed in industry by companies, such as Textron Systems Corporation. Axial thrust is independently provided by a pusher propeller.…”

Section: Introductionmentioning

confidence: 99%

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Observer-Based Optimal Control of a Quadplane with Active Wind Disturbance and Actuator Fault Rejection

Zyadat

Horri

Innocente

et al. 2023

Sensors

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Hybrid aircraft configurations with combined cruise and vertical flight capabilities are increasingly being considered for unmanned aircraft and urban air mobility missions. To ensure the safety and autonomy of such missions, control challenges including fault tolerance and windy conditions must be addressed. This paper presents an observer-based optimal control approach for the active combined fault and wind disturbance rejection, with application to a quadplane unmanned aerial vehicle. The quadplane model is linearised for the longitudinal plane, vertical takeoff and landing and transition modes. Wind gusts are modelled using a Dryden turbulence model. An unknown input observer is first developed for the estimation of wind disturbance by defining an auxiliary variable that emulates body referenced accelerations. The approach is then extended to simultaneous rejection of intermittent elevator faults and wind disturbance velocities. Estimation error is mathematically proven to converge to zero, assuming a piecewise constant disturbance. A numerical simulation analysis demonstrates that for a typical quadplane flight profile at 100 m altitude, the observer-based wind gust and fault correction significantly enhances trajectory tracking accuracy compared to a linear quadratic regulator and to a H-infinity controller, which are both taken, without loss of generality, as benchmark controllers to be enhanced. This is done by adding wind and fault compensation terms to the controller with admissible control effort. The proposed observer is also shown to enhance accuracy and observer-based rejection of disturbances and faults compared to three alternative observers, based on output error integration, acceleration feedback and a sliding mode observer, respectively. The proposed approach is particularly efficient for the active rejection of actuator faults under windy conditions.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Observer-Based Optimal Control of a Quadplane with Active Wind Disturbance and Actuator Fault Rejection

Zyadat

Horri

Innocente

et al. 2023

Sensors

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“…However, to the authors´ best knowledge, little research can be found in the literature that addresses the issue of the redundancy or over-actuation of the dual-system VTOL UAVs to enhance the abilities of such airplanes. Recently, this problem has been targeted by Porchazka et al [7][8][9] where employing the pair of forward and backward rotors of the vehicle was used with the elevator to control the longitudinal dynamics of the airplane only performing a pitching maneuver at certain ight speed with testing the fault-tolerance against elevators' faults. However, the control system presented in [7][8][9] did not present a complete architecture that can perform complete mission from takeoff to landing with the redundancy employed and did not include the lateral dynamics in the study.…”

Section: Introductionmentioning

confidence: 99%

“…In cases of fault existence, the command of the acceleration along z-direction is dropped down and only the 3 rotational accelerations are passed to the control allocator. The fault detection and isolation (FDI) design is not in the scope of this study thus it is assumed that once faults happen they are detected, which is done in similar studies [7][8][9].…”

mentioning

confidence: 99%

“…Figure 10 shows the ight trajectory of the same airplane loitering at the same ight speed. The blue trajectory is obtained by employing the control surfaces only with the vertical rotors shut off, which is the case of the traditional control systems found in the literature [7][8][9], and the red trajectory is for the same airplane but with the ight control system proposed in this study.…”

mentioning

confidence: 99%

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Promoting The Maneuverability and Fault-tolerance Capabilities of Dual-system VTOL UAVs

Salem

Mohamady

Draz

et al. 2022

Preprint

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This paper proposes a new architecture for the flight control system of dual-system vertical takeoff and landing (VTOL) unmanned aerial vehicles (UAVs). Having two separate systems for vertical and horizontal thrust in addition to the conventional control surfaces makes it the simplest VTOL UAV configuration, however, less employment of its controls redundancy is a drawback and a waste of its inherent capabilities. The main contribution of the designed control system is to employ the control's redundancy to enhance the airplane's maneuverability and to achieve fault-tolerance via the control allocation technique, thus benefiting from the vertical rotors during all the flight phases rather than having them as dead weights during the majority of the flight. The designed control system performs full flight missions including VTOL, transitions, cruise, and loiter in fault and fault-free cases with allowable commands for all the healthy controls according to their effectiveness, following the desired trajectory while minimizing the energy consumption and aerodynamic drag as well. A severe fault scenario is presented that includes sudden jamming of all the control surfaces where the control system successfully completed the intended mission as in the fault-free case. The proposed control system proved to enhance the maneuverability by achieving a 38% reduction in the coordinated steady-level turn radius at a given flight speed compared to the minimum turn radius achieved using the control surfaces only. The results reveal the dual-system configuration's safety and reliability features, recommending it as a first choice in VTOL UAVs applications.

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Promoting the Maneuverability and Fault-Tolerant Control Capabilities of Dual-System/Hybrid VTOL UAVs

Salem,

Mohamady,

Draz

et al. 2023

Arab J Sci Eng

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This paper presents an active fault-tolerant flight control system (FCS) design for the dual-system/hybrid VTOL UAV configuration that maximally exploits its inherent over-actuation abilities to provide higher levels of fault-tolerance and reliability compared to that of the other VTOL UAVs configurations up to this point. The significance of this study is to convert the main drawback of having the vertical rotors as dead weights during the cruise to a key advantage where all the UAV's controls are kept active during all the flight phases raising the UAV's fault-tolerance and maneuverability abilities. The FCS proposed elaborates on a new architecture for the hierarchical automatic control loops using the dynamic inversion control to design the trajectory tracking virtual commands and employing optimal dynamic control allocation to optimally resolve the controls redundancy. Regarding fault-tolerance, the presented FCS handles simultaneous failures and jamming of all the control surfaces during flight where the control commands to the healthy controls (vertical rotors) were automatically adapted such that the trimming and trajectory tracking were successfully maintained till the mission end. Additionally, this paper addresses for the first time the employment of the controls redundancy to enhance the VTOL UAV's maneuverability in fault-free cases, where we present a study of reducing the minimum turn radius of the UAV when the vertical rotors are employed with the control surfaces during the maneuver. A reduction of 38% in the coordinated steady-level minimum turn radius turn at 35 m/sec flight speed was achieved.

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Integral Sliding Mode based Model Reference FTC of an Over-Actuated Hybrid UAV using Online Control Allocation

Cited by 7 publications

References 16 publications

Observer-Based Optimal Control of a Quadplane with Active Wind Disturbance and Actuator Fault Rejection

Observer-Based Optimal Control of a Quadplane with Active Wind Disturbance and Actuator Fault Rejection

Promoting The Maneuverability and Fault-tolerance Capabilities of Dual-system VTOL UAVs

Promoting the Maneuverability and Fault-Tolerant Control Capabilities of Dual-System/Hybrid VTOL UAVs

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