Reliability Analysis, Design Improvements and Maintenance Procedure Compilation of a Novel Remotely Piloted Helicopter

Sensors

This paper focuses on the development of a new logistic approach based on reliability and maintenance assessment, with the final aim of establishing a more efficient interval for the maintenance activities for Unmanned Aerial Vehicles (UAV). In the first part, we develop an architectural philosophy to obtain a more detailed reliability evaluation; then, we study the intrinsic reliability at the design stage in order to avoid severe critical issues in the UAV. In the second part, we compare different maintenance philosophies for UAVs and develop the concepts of preventive and corrective maintenance that consider the system subjected (until real “hard failure”) to partial performance degradation (“soft failure”). Finally, by evaluation of the uncertainty through the confidence interval, we determine the new soft failure limits, taking into account the general knowledge of the systems and subsystems in order to guarantee the proper preventive maintenance interval.

The present work aims at discussing the use of the failure analysis methods in Unmanned Aerial Vehicle (UAV) applications, focusing the design review procedures with Failure Modes and Effects Analysis (FMEA) and Fault Tree Analysis (FTA). UAV are typically currently unreliable, and lack systems to improve their reliability. It is shown that the use of these tools will lead to reliability improvement by means of the implementation of countermeasures to potential failures as well as to determine the importance of these failures from various perspectives such as cost, reliability and safety. As an example of implementation of such tools, we adapted forms from commercial use for FMECA system for UAV, and a FTA regarding loss of propulsion for a UAV are briefly presented and discussed.

2017

This paper presents the models and methods for reliability synthesis for components of UAV flight control system: flight computer and navigation system. The developed reliability models depict different variants of faulttolerant designs including designes for systems with complex reliability behavior. They have a high level of adequacy, since effectiveness of detection and switching devices was taken into account. Based on the models, we proposed the reliability synthesis methods for flight control system components that allows making reasonable design decisions. As an example of using these methods, the reliability requirements and recommendations for rational choice of fault-tolerant designs were developed to meet required reliability level of UAV flight computer and navigation system.

Australian Journal of Basic and Applied Sciences, 2009

Remotely piloted vehicles are usually deployed in various applications especially those requiring remote sensing. RPV's, as they are usually called, are very versatile remote data collection tools, especially for aerial imaging of hard to reach terrain such as mountains and deserts. The sensed images obtained from several such RPV's may be either fused together in a data fusion system, or may be individually used for various engineering applications. The reliability of these unmanned remotely piloted vehicles is of great concern due to the vast amount of expenses incurred in setting up an engineering program to sense RPV obtained data in a given application. The most common approaches for the analysis of the reliability of systems are the state space approach and the reliability block diagram (RBD) approach. The expected operating conditions of the system also play an important role in the analysis of the reliability of the system since they affect its mean lifetime. In this study, RBD and state space modeling are used for the analysis of the reliability of the guidance, navigation and control computer system of a remotely piloted vehicle in its various expected operating conditions during its lifetime. It is shown that the reliability of the system may be effectively improved by designing in redundancy where none of the other viable measures of reliability growth are available to us. Measures of reliability such as MTTF, MTTR, and availability are estimated under various system operating conditions.

1981

The division's philosophy for designed-in reliability and a comparison of reliability programs for space, manned military aircraft, and commercial aircraft, are presented. Topics include: the reliability interface with design and production; the concept phase through final proposal; the design, development, test and evaluation phase; the production phase; and the commonality among space, military, and commercial avionics.

Scientific Research Journal

Hazard in technological development can occur anywhere, anytime, and caused by various factors. Every technology product has the possibility to failed or error in its operation. This failure can endanger the product itself, its users or the environment around it. The purpose of this research is to design mitigation for failure conditions at the system level in order to minimize and avoid the impact of failure conditions on an unmanned aircraft named PTTA MALE .The method used is descriptive qualitative method including architecture observation, discussion and interviews with experts. Research was also conducted using quantitative methods based on international standard documents (ARP 4761 & STANAG 4671) to improve the analysis of failure conditions. Mitigation design with a System Functional Hazard Assessment (SFHA) is carried out for each system level failure condition. Failure conditions are generally categorized into detected, undetected, announced and unannounced failures. When a failure condition occurs, the pilot can take action according to the best mitigation that has been designed, for example by turning off the automatic power control, or continuing the operation in manual mode. The results of this research can serve as a guide for pilots in operating PTTA MALE.

The main goal of this report is to review the literature on reliability of Unmanned Ground Vehicles (UGV) and to identify key research areas for improving their reliability. The report begins with definition of a UGV and explanation of the need for improving its reliability. The literature review, which summarizes two major UGV reliability studies, is followed by a classification of failures section. Common failure and reliability analysis methods are then discussed. The report concludes by a summary of key points and identification of research areas for improving UGV reliability.

This paper deals with the architecture definition and the safety assessment of flight control systems for light remotely-piloted helicopters for civil applications. The methods and tools to be used for these activities are standardised for conventional piloted aircraft, while they are currently a matter of discussion in case of light remotely-piloted systems flying into unsegregated airspaces. Certification concerns are particularly problematic for aerial systems weighing from 20 to 150 kgf, since the airworthiness permission is granted by national authorities. The lack of specific requirements actually requires to analyse both the existing standards for military applications and the certification guidelines for civil systems, up to derive the adequate safety objectives. In this work, after a survey on applicable certification documents for the safety objectives definition, the most relevant functional failures of a light remotely-piloted helicopter are identified and analysed via Functional Hazard Assessment. Different architectures are then compared by means of Fault-Tree Analysis, highlighting the contributions to the safety level of the main elements of the flight control system (control computers, servoactuators, antenna) and providing basic guidelines on the required redundancy level.

International Journal of Industrial Ergonomics, 2010

In this paper a statistical analysis of a sample of 58 helicopter maintenance-induced safety occurrences is conducted to study helicopter accidents and incidents' survivability and the severity distribution of such occurrences. Analysis is also carried out to identify helicopter main and subsystems mostly exposed to maintenance errors and to determine various types of such errors. Expected inherent relations between rotorcraft components affected and types of associated maintenance errors are investigated. Human factors-based triggers of these accidents and severe incidents are explored. The concept of Specific Failures (SFs) that immediately precede each of such occurrences is introduced for more detailed representation of the last breached individual and organizational safety barriers. Root causes of these safety occurrences were then sought utilizing the Human Factors Analysis and Classification System-Maintenance Extension (HFACS-ME) taxonomy with a refined focus on its third order categories' list. The rotorcraft characteristics influencing individuals and organizational behaviours within Maintenance, Repair and Overhaul organizations (MROs) are discussed in the light of the root cause investigation results. Relevance to industry: The study of human reliability within helicopter maintenance industry is waited to emphasise the understanding of causes and propagation mechanisms of maintainers' errors and their consequences on the overall aviation safety. Previous works often investigated maintenance errors and their roles in promoting aviation accidents of fixed-wing aircraft; this research is investigating the case of rotorcraft.

Journal of Konbin, 2010

A Method of Aircraft Reliability Assessment as Referred to the Operational-Use Safety Throughout the operational phase of aviation objects, the safety and reliability thereof are characterised with a set of a dozen or so, or even tens of indices correlated with each other. Hence, any analytical and assessment-oriented efforts as well as comparisons - for any specific feature - between both the objects themselves and the systems of manufacturing, operating, and maintaining them are usually hindered. The intended aim of this paper is to suggest some solution to this problem, one that consists in reducing the number of operational indices of safety down to several indices of significance which contain most information on the object under assessment or on a system of operating this object