Line Replaceable Modules Research Articles

An Intelligent Fleet Condition-Based Maintenance Decision Making Method Based on Multi-Agent

According to the demand for condition-based maintenance online decision making among a mission oriented fleet, an intelligent maintenance decision making method based on Multi-agent and heuristic rules is proposed. The process of condition-based maintenance within an aircraft fleet (each containing one or more Line Replaceable Modules) based on multiple maintenance thresholds is analyzed. Then the process is abstracted into a Multi-Agent Model, a 2-layer model structure containing host negotiation and independent negotiation is established, and the heuristic rules applied to global and local maintenance decision making is proposed. Based on Contract Net Protocol and the heuristic rules, the maintenance decision making algorithm is put forward. Finally, a fleet consisting of 10 aircrafts on a 3-wave continuous mission is illustrated to verify this method. Simulation results indicate that this method can improve the availability of the fleet, meet mission demands, rationalize the utilization of support resources and provide support for online maintenance decision making among a mission oriented fleet.

Cooperative game approach based on agent learning for fleet maintenance oriented to mission reliability

Fleet maintenance oriented to mission reliability is a multi-level maintenance planning problem that becomes highly difficult due to the various reliability models of equipment and fleet. A three-level decision structure for fleet maintenance is established, the objective is maintenance cost, the constraints is the reliability of fleet, and the variables are the maintenance statuses of line replaceable modules. Then, the fleet maintenance process is translated into game behavior among considerable equipment with different statuses. A cooperative game framework based on agent learning is developed. A convergence condition for optimization is proposed by a simulated annealing approach. In the game method, three types of learning signals and their evaluation rules are introduced to establish the equipment’s reduced strategy space. Thus, the computation amount of game can be controlled, and the reliability constraints can be satisfied during the game process. Furthermore, the assessment method for the equipment payoff with a penalty factor is established, and the rapid search algorithm of Pareto optimal solution is provided on the basis of the total revenue of game. A case study is performed on a fleet of 15 aircrafts to prove that the proposed approach can reduce the maintenance cost effectively and can meet the fleet mission reliability requirements.

An Approach to Develop a Remotely Operated Integrated Avionics Test Suit

AbstractIntegration testing and functional validation & verification are few of the key phases of Aircraft Development Life Cycle. This is performed by integrating the avionic system on complex dynamic test platforms in a controlled lab environment. The avionic systems are in general, composed of a combination of multiple LRUs (Line Replaceable Units) / LRMs (Line Replaceable Modules). Test platforms referred to as Integrated test benches (ITB) comprise of dynamic aircraft simulation models running on multiple host computers, IO servers, breakouts, power supply control units and internal airflow management modules for avionics cooling. This paper proposes a means of making the Integration Test Benches remotely available across multiple locations seamlessly, without incurring substantial cost, thereby eliminating the need for building and maintaining the test benches at multiple locations. This approach explores a novel technique that can be leveraged to make a single bench accessible globally within the organization by leveraging various concepts of IOT (Internet of things) and cloud technology.

모듈통합형 항공전자시스템을 위한 Video Processing Module 구현

모듈통합형 항공전자시스템은 연방형의 LRU (line replaceable unit)의 기능을 하나의 LRM (line replaceable module)에서 제공하고, 하나의 cabinet에 여러 개의 LRM을 탑재한다. IMA core 시스템의 VPM (video processing module)은 LRM으로써 ARINC 818 ADVB (avionics digital video bus)의 bridge 및 gateway 역할을 한다. ARINC 818은 광 대역폭, 적은 지연시간, 비 압축 디지털영상 전송을 위해 개발된 규격이다. VPM의 FPGA IP core는 ARINC 818 to DVI 또는 DVI to ARINC 818 처리와 video decoder, overlay 기능을 가진다. 본 논문에서는 VPM 하드웨어 구현에 대해 다루고, VPM 기능과 IP core 성능 검증 결과를 보인다. The integrated modular avionics (IMA) system has quite a number of line repalceable moduels (LRMs) in a cabinet. The LRM performs functions like line replaceable units (LRUs) in federated architecture. The video processing module (VPM) acts as a video bus bridge and gateway of ARINC 818 avionics digital video bus (ADVB). The VPM is a LRM in IMA core system. The ARINC 818 video interface and protocol standard was developed for high-bandwidth, low-latency and uncompressed digital video transmission. FPGAs of the VPM include video processing function such as ARINC 818 to DVI, DVI to ARINC 818 convertor, video decoder and overlay. In this paper we explain how to implement VPM's Hardware. Also we show the verification results about VPM functions and IP core performance.

An optimization method for condition based maintenance of aircraft fleet considering prognostics uncertainty.

An optimization method for condition based maintenance (CBM) of aircraft fleet considering prognostics uncertainty is proposed. The CBM and dispatch process of aircraft fleet is analyzed first, and the alternative strategy sets for single aircraft are given. Then, the optimization problem of fleet CBM with lower maintenance cost and dispatch risk is translated to the combinatorial optimization problem of single aircraft strategy. Remain useful life (RUL) distribution of the key line replaceable Module (LRM) has been transformed into the failure probability of the aircraft and the fleet health status matrix is established. And the calculation method of the costs and risks for mission based on health status matrix and maintenance matrix is given. Further, an optimization method for fleet dispatch and CBM under acceptable risk is proposed based on an improved genetic algorithm. Finally, a fleet of 10 aircrafts is studied to verify the proposed method. The results shows that it could realize optimization and control of the aircraft fleet oriented to mission success.

The death of smart sensors and effectors for future combat aircraft

This paper presents the view that the combination of performance, availability and affordability requirements for future combat aircraft demands a concept for low-bandwidth sensor/effector interfacing which removes the need for smart sensors and effectors. This contrasts sharply with current trends for civil aircraft. The paper discusses the reasons for the above, then describes a concept which extends modular avionics into the low-bandwidth sensor/effector interfacing domain. Modular avionics programmes concentrate on the core digital processing and/or the high-bandwidth sensor/effector interfacing (RF modules, integrated sensor system [ISS], etc.). Low-bandwidth sensors and effectors (temperature, pressure, position, switches, lamps, etc.) need to be interfaced to the core processing, and are an important part of the availability equation since they are often essential for flight. The paper therefore proposes that: 1. (1) Modular avionic architecture characteristics and goals can be applied to the low-bandwidth interfacing domain 2. (2) “Open system” standardization of low-bandwidth interface components is possible, leading to cost savings 3. (3) Hardware and software elements designed for the core digital processing can be re-used in the low-bandwidth interfaces, further improving affordability 4. (4) The drivers for civil and military aircraft are different, but a common solution is possible. The paper covers the following topics: 1. (1) Key requirements for combat aircraft (derived from goals for LCC, mission performance, operational performance), and differences between civil and military requirements 2. (2) Modular low-bandwidth interfacing concept 3. (3) Overview (signal concentrators in an integrated avionic architecture): hardware building blocks (line replaceable interface modules); data transmission (within signal concentrators and to the core processing); software 4. (4) Conclusions (implications for modular avionics standardization, smart sensors/effectors and the potential for a common civil/military approach).

Simulation of future system data networks

The rapid development of avionic system technology over the last two decades has provided a quantum leap in system capability and performance. The cost of developing, manufacturing and supporting avionic systems has also risen considerably. It is now recognised that future technology must emphasise low life-cycle costs and flexibility, as well as mission effectiveness. The modular approach to avionic system design and construction is widely considered to be the way to meet future requirements. There are a number of significant technical risks associated with the modular approach. One major risk area is the transmission of data between avionic modules (known as Line Replaceable Modules or LRMs) and between modules, and sensor and display systems. Data transmission technology is developing rapidly, and there is a range of candidate network solutions to meet the modular system requirements. A cost-effective way to carry out an assessment of the candidate networks is by means of simulation. However, it is important that simulations use realistic data rather than statistical data arrival distributions. This paper describes a programme in which realistic data flows were defined for two avionic system implementations covering 1997 and 2007 timescales. One implementation was based upon the Pi-Bus and LTPB combination, and another featured a ‘unified’ SCI data network. The data flows were subsequently provided to DRA for simulation. The paper addresses a number of stages of the programme, including. • the system engineering process of developing logical (functional) models of the systems and mapping them to physical (implementation) models, • the design of a ‘unified’ network using SCI, • extensions to basic network simulation (e.g. transfer layer, reconfiguration and system behaviour). Conclusions identify the necessity for more advanced tools to assist with the design, simulation and build of systems that incorporate these data networks.

ARINC 653 — Challenges of the present and future

ARINC 653 is currently one year from the completion of its first phase. Phase 1 is intended to meet the requirements of the most critical systems which require strictly deterministic periodic processing. The original hardware platform envisaged for software conforming to ARINC 653 was cabinet-based line replaceable modules communicating with each other over the ARINC 659 backplane databus. However, ARINC 653 conformant software must be compatible with other hardware configurations such as the proposed Avionics Computing Resource (RTCA SC-182) and LRMs with direct ARINC 629 connections and ARINC 429 based systems. This paper describes the challenges facing the ARINC 653 working group in defining a sufficiently rigorous specification of services without constraining the developer to a particular system architecture. The external communications mechanisms and configuration information necessary to realize the aims of portability and re-use are considered. The achievement of ‘time partitioning’ on a shared processor resource is discussed. The paper concludes with a discussion of future extensions to ARINC 653 to enable reconfiguration of applications both statically and dynamic- ally, and to accommodate aperiodic processes.

SAFEbus (for avionics)

The Airplane Information Management System (AIMS) for the Boeing 777 wide-body engine will be the first highly integrated avionics system for commercial transport. A description is given of the backplane bus, called SAFEbus, that provides communications of all data among the line replaceable modules (LRMs) in the AIMS cabinets. SAFEbus consists of two self-checking buses. The overriding goal in the design of SAFEbus has been to prevent unintended and undetected interactions among the integrated avionics functions and to control complexity so that airplane certification is straightforward. SAFEbus is slated to become the first standard backplane bus for commercial avionics, having been accepted as the draft for ARINC Project Paper 659. >

Integrated communications, navigation, identification avionics (ICNIA)-the next generation

A description is given of an approach developed for the ICNIA (integrated communications, navigation, identification avionics) design that uses a small number (28) of types of self-testing line replaceable modules (LRMs) to configure current and future fixed- or rotary-wing aircraft radio suites while replacing the current logistic tails for over 1000 fielded shop-replaceable units. The flexibility of the ICNIA architecture is demonstrated by examining the methods by which it could be inserted into future totally integrated avionics architectures. Embedded data and processing rates, advanced architecture considerations, and system security/partitioning issues are discussed. >