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Technical Paper

Evaluation of Control Strategies for Single Flap Drive Systems in Multifunctional High Lift Systems

The continuous need for improved high lift performance motivates the evaluation of innovative high lift systems. Single flap drive systems are possible solutions to implement novel functionalities for aerodynamic performance optimization. The previously mechanical coupling needs to be replaced by approved equivalent means. This directly results in high demands on control and monitoring of the multiple single drive systems in order to preserve a safe operation. In the context of the national German research project SysTAvio, strategies for a new concept of a multifunctional high lift system are investigated and presented in this paper. The conceptual system comprises four single flap surfaces, each driven by a local transmission system and powered by a local power control unit. This architecture requires an innovative control strategy for a safe operation of a single drive system as well as synchronous movement of multiple systems.
Technical Paper

Architecture and Parameter Optimization for Aircraft Electro-Hydraulic Power Generation and Distribution Systems

The All-Electric-Engine with only electrical power offtake is a main goal in aircraft system development. The use of electric-motor pumps instead of engine-driven pumps for powering the central hydraulic systems could be a part of this objective. Additionally, the concept would meet the incremental development strategy performed by the aerospace industry today and saves costs by using state-of-the-art hydraulic actuation technology. This paper describes a process for optimizing such systems regarding their architecture and design parameters. For this task a methodology for the hydraulic consumer allocation called OPAL is used and extended by an automatic power system sizing. Feasible allocations, called permutations, are determined on the basis of preliminary system safety assessments regarding multiple top failure events. In the next step an automated sizing of the permutations is performed based on simplified hydraulic load analyses.
Technical Paper

Optimization of the Power Allocation for Flight Control Systems

Due to a shift of the major aviation concerns to focus on enhancements of the successful programs instead of pushing their successors, the need for new methodologies for aircraft system architecture design emerges. Challenging the existing requirements and reconsidering the functions and their allocation could help to dissolve the system specific development paradigm and lead to beneficial architecture concepts. To help understand the mechanisms and boundary conditions of developing fault-tolerant systems, the first part of the paper gives an overview of the successive process of architecture design. The significant architectural design decisions and the concurrent safety assessment process are discussed. One crucial step in the design space exploration of future aircraft system architectures is the allocation of the consumers to the available power sources. Within the paper a methodology for the optimization of the power allocation for flight control systems is proposed.
Technical Paper

Multi-Objective Design of Optimized Diagnosis Functions for High Lift Actuation Systems

This paper presents a model-based approach for the multi-objective design of optimized diagnosis functions for high lift actuation systems. These systems are used to augment lift at low speed during takeoff and landing, and are safety critical. This demands requirements to the detection of failures and the isolation of root causes in order to provide a high availability at low risk. Dedicated functions cover the determination of features, the detection of symptoms and the isolation of root causes by means of inference and resolution. The aim of the design approach is to provide these functions in an optimal manner with respect to multiple objectives. In order to be clear and traceable the approach consists of separate consecutive steps. These are arranged by using systems engineering principles. With respect to requirements, models of different levels of detail are developed and used to design stepwise all required functions.
Technical Paper

Accuracy Analysis and Error Source Identification for Optimization of Robot Based Machining Systems for Aerospace Production

Strong market growth, upcoming global competition and the impact of customer-requirements in aerospace industry demand for more productive, flexible and cost-effective machining systems. Industrial robots have already demonstrated their advantages in smart and efficient production in a wide field of applications and industries. However, their use for machining of structural aircraft components is still obstructed by the disadvantage of low absolute accuracy and adverse reaction to process loads. This publication demonstrates and investigates different methods for performance assessment and optimization of robot-based machining systems. For conventional Cartesian CNC machining systems several methods and guidelines for performance assessment and error identification are available. Due to the attributes of a common 6-axis-robot serial kinematics these methods of decoupled and separated analysis fail, especially concerning optimization of the system.
Journal Article

A Methodology for Rapid Evaluation and Sizing of Fuel Cell System Architectures for Commercial Aircraft

This paper presents a methodology to develop, optimize and evaluate fuel cell system architectures. The main focus is placed on the sizing and optimization process which uses the simulation tool Matlab/Simscape. A model library is introduced which contains parametric behavior models. The benefit of this is that the size of the components is not fixed by the parameters. The size of the components is driven by the energy and mass flows of each component. Thus the implicit sizing and optimization process is easy to handle and numerically robust. Illustrative results are shown for a fuel cell system.
Journal Article

Recent Advances Towards an Integrated and Optimized Design of High Lift Actuation Systems

For actuation of high lift surfaces in modern airplanes, complex mechanical shaft transmission systems powered by central drive units are deployed. The design of mechanical actuation systems, which have a major share in the weight of secondary flight controls, is a complex and challenging engineering task. Especially for specification of essential component and system design parameters within the preliminary design phase, engineering skill and experience are of significant importance owing to many uncertainties in component data and boundary conditions. Extensive trade-offs, as well as an evaluation of the system requirements and constraints lead to an iterative and time-consuming design process. Utilizing an integrated design assistance tool, mathematical functions and constraints can be modeled on system and component level and formalized as a constraint satisfaction problem (CSP). Thus, automated consistency checking and pruning of the solution space can be achieved.