Fault-Tolerant Actuation Architectures for Unmanned Aerial Vehicles

Ismail, Mohamed A.A.; Bosch, Colin; Wiedemann, Simon; Bierig, Andreas

doi:10.1007/978-981-15-9199-0_32

Cited by 9 publications

(5 citation statements)

References 11 publications

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“…On the other hand, the actuator level FTAD concentrates on enhancing actuator reliability. Ismal et al investigated the off-the-shelf technologies, identifying six types of state-of-the-art architecture designs [24].…”

Section: Design Methodologymentioning

confidence: 99%

A Decentralized Voting and Monitoring Flight Control Actuation System for eVTOL Aircraft

He,

Holzapfel,

Bröcker

et al. 2024

Aerospace

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The emergence of eVTOL (electrical Vertical Takeoff and Landing) aircraft necessitates the development of safe and efficient systems to meet stringent certification and operational requirements. The primary state-of-the-art technology for flight control actuation in eVTOL aircraft is electro-mechanical actuators (EMAs), which heavily rely on multiple redundancies of critical components to achieve fault tolerance. However, challenges persist in terms of insufficient reliability, immaturity, and a lack of a measurable evaluation method. This research addresses these issues by elucidating the design requirements for EMAs in eVTOL aircraft and proposing a systematic design and evaluation approach for EMA architecture. A key enhancement involves the incorporation of decentralized voting and monitoring (VoDeMo) mechanisms within the Electronic Control Units (ECUs) to improve the overall safety of the EMA. The paper introduces an innovative triple-dual redundant architecture for aircraft control effectors, comprising three dissimilar lanes of ECUs and two similar redundant parallel channels of power electronics and motors. The design is synergistically supported by a comprehensive evaluation that incorporates quantifiable Model-Based Safety Assessment (MBSA), utilizing both physical simulation and logical safety models. Hardware-In-the-Loop (HIL) tests are conducted on a constructed prototype to validate the proposed architecture.

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Section: Design Methodologymentioning

confidence: 99%

A Decentralized Voting and Monitoring Flight Control Actuation System for eVTOL Aircraft

He,

Holzapfel,

Bröcker

et al. 2024

Aerospace

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“…The flexspline has a nonlinear stiffness that is a function of the flexspline torque. The flexspline torsion can be defined as in (6):…”

Section: B Compliance Modelmentioning

confidence: 99%

Simplified Sensorless Torque Estimation Method for Harmonic Drive Based Electro-Mechanical Actuator

Ismail

Windelberg

Liu

2021

IEEE Robot. Autom. Lett.

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Torque measurements can significantly enhance control and monitoring loops for many mechatronic and aerospace applications. A typical challenge is to justify incorporating a torque sensor in terms of cost, system complexity, and reliability. Recently, sensorless torque estimation methods have been developed for robotic joints that include harmonic drive transmissions (HDTs). The principle is based on their relatively low torsional stiffness, which allows for estimating the transmitted torque by measuring the torsional angles (via existing joint encoders) and a compliance model. However, these methods are based on nonlinear models that are difficult to identify and tune. In this study, a simplified torque estimation method is introduced based on the structural damping friction of the HDTs. The structural damping can be correlated to the HDT torque using a simplified linear dynamic model and torsional rate measurements. Experimental results have validated the proposed method, using a robotic joint setup with an external torque sensor that has been previously utilized for testing several torque estimation methods.

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“…There are many growing civil and military applications for unmanned aerial vehicles (UAVs) due to their low acquisition and operating costs. However, the reliability of inservice UAVs does not match the superior levels of general aviation [1,2] signaling that the root causes should be identified and mitigated by health monitoring systems. In this paper, the focus is on flight control electro-mechanical actuators (EMAs) because their failures have a significant impact on the total system failures of in-service UAVs, according to US Office of the Secretary of Defense [3].…”

Section: Introductionmentioning

confidence: 99%

Spall Fault Quantification Method for Flight Control Electromechanical Actuator

2022

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Flight control electro-mechanical actuators (EMAs) are among the primary onboard systems that significantly influence the reliability and safety of unmanned aerial vehicles. Recent reliability studies have shown that the ball-screw element of a flight control EMA is subject to oscillating operating conditions that may initiate rapid degradation, such as fatigue spall defects. Accordingly, detecting and quantifying such faults are crucial for developing efficient fault prognostic and remaining useful life estimation capabilities. In this study, a vibration-based fault quantification method is developed to quantify the fatigue faults of a ball-screw mechanism of an EMA. The method is based on identifying the ball passing instants through a localized surface defect on the vibrational jerk rather than the vibrational acceleration measurement. The jerk is numerically determined from conventional accelerometers using a Savitzky–Golay differentiator. This method was successfully tested for ball bearings and it is adjusted in this paper for ball-screw faults. The experimental validation is investigated on a set of fault-seeded samples on NASA’s Ames Research Center Flyable Electro-Mechanical Actuator test stand.

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Fault-Tolerant Actuation Architectures for Unmanned Aerial Vehicles

Cited by 9 publications

References 11 publications

A Decentralized Voting and Monitoring Flight Control Actuation System for eVTOL Aircraft

A Decentralized Voting and Monitoring Flight Control Actuation System for eVTOL Aircraft

Simplified Sensorless Torque Estimation Method for Harmonic Drive Based Electro-Mechanical Actuator

Spall Fault Quantification Method for Flight Control Electromechanical Actuator

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