Iron Bird Research Articles

Design and Implementation of a Hardware-in-the-Loop Air Load Simulation System for Testing Aerospace Actuators

This paper presents the design and implementation of the hardware and control strategies of an electrohydraulic air load simulation system for testing aerospace actuators. The system is part of an Iron Bird, which is an energy management research platform developed in collaboration between Saab AB and Linköping University. The purpose of the air load system is to provide realistic forces on the test object through the integration of a flight simulator for full mission evaluation. The challenge with electrohydraulic force control is tackled by increasing the hydraulic capacitance from increased load cylinder dead volumes, together with a feed-forward link based on accurate modelling of the test object and load system by adopting an optimisation routine to find model parameters. The system is implemented for both an electromechanical and servohydraulic actuator as test objects with different performance requirements. The control design is based on nonlinear and linear modelling of the system, and experimental test data are used to tune the models. Finally, test results of the air load system prove its force-tracking performance.

Parameter Adjustment of the Autothrust Control Law by Flight Tests

Aiming at deriving precise automatic control of airspeed, a comprehensive flight test solution for autothrust control law parameter adjustment was proposed, providing a worthy reference for other aircraft types’ work, including the flight test points and methods, aircraft modification requirements for the test, the system performance analysis and evaluation methods, and the flight test risk analysis. A method invoking test scripts by a flight test interface unit and a control panel to configure parameters of autothrust control law and input excitation signals was proposed for the first time. The test scripts and the test devices cross-link can be fully verified in advance in both iron bird and real aircraft ground tests, which can greatly reduce unexpected risks of the test method based on the flight test engineers’ personal experience. According to the evaluation from three aspects of system response, robustness and throttle lever movement based on the test data, the optimal autothrust control law parameters configuration was given.

When the Iron Bird Flies: China's Secret War in Tibet

When the Iron Bird Flies: China's Secret War in Tibet

Design and Preliminary Performance Assessment of a PHM System for Electromechanical Flight Control Actuators

The evolution toward “more electric” aircraft has seen a decisive push in the last decade due to growing environmental concerns and the development of new market segments (flying taxis). Such a push has involved both the propulsion components and the aircraft systems, with the latter seeing a progressive trend in replacing traditional solutions based on hydraulic power with electrical or electromechanical devices. Flight Control Systems (FCSs) are one of the aircraft systems affected the most since the adoption of Electromechanical Actuators (EMAs) would provide several advantages over traditional electrohydraulic or mechanical solutions, but their application is still limited due to their sensitivity to certain single points of failure that can lead to mechanical jams. The development of an effective and reliable Prognostics and Health Management (PHM) system for EMAs could help in mitigating the risk of a sudden critical failure by properly recognizing and tracking the ongoing fault and anticipating its evolution, thus boosting the acceptance of EMAs as the primary flight-control actuators in commercial aircraft. The paper is focused on the results of the preliminary activities performed within the CleanSky 2/Astib research program, dedicated to the definition of the iron bird of a new regional-transport aircraft able to provide some prognostic capabilities and act as a technological demonstrator for new PHM strategies for EMAs employed in-flight control systems. The paper is organized as follows. At first, a proper introduction to the research program is provided, along with a brief description of the employed approach. Hence the simulation models adopted for the study are presented and used to build synthetic databases to inform the definition of the PHM algorithm. The prognostic framework is then presented, and a preliminary assessment of its expected performance is discussed.

Seleksi dan Penentuan Third Party Logistik Transportasi Produk Pelumas Menggunakan Metode TOPSIS dan PROMETHE

Selection of Third Party Logistics (3PL) services is an important focus of attention for companies in selecting suppliers in their supply chain. The wide marketing area of PT PETRONAS's lubricant products demands 3PL performance to increase the company's service level. The purpose of this study is to analyze the decision-making process in the context of selecting 3PL transportation suppliers using the TOPSIS and PROMETHE multi-criteria methods. The type of data used consists of primary data and secondary data through library research, interviews, and field surveys. The process of selecting a transportation 3PL is carried out in two stages, namely selection of criteria and the commercial aspect of the bidding price per region is evaluated as the basis for selecting the best supplier. The selected suppliers are PT Wira Logitama Saksama, PT Glory sogotrans Mandiri, PT Iron Bird Logistik, PT Sumisho Global Logistik, and PT Dunia Express Transindo. Based on the results of the analysis using the PROMETHEE method, five criteria with the highest weight were produced, namely Price, Time Delivery, Health Safety Management, Infrastructure and Office Equipment. The results of the ranking using the TOPSIS method for shipping to each destination are that PT Wira Logitama Semesta is the best supplier for five shipping destinations, namely Jabodetabek, Bandung, Surabaya, Lampung and Medan and PT Iron Bird Logistik is the best supplier for shipping to Cilegon and Semarang.

Structural FEM Analyses of a Landing Gear Testing Machine

The “Electro-mechanical Landing gear system Integration for Small Aircraft” (E-LISA) research project has the objective of developing an innovative “iron bird”, a testing facility dedicated to executing tests on an innovative landing gear of a small aircraft. This document presents the structural analyses of this complex testing machine performed with the Finite Element Method (FEM). Key purposes of these numerical simulations were the quantifications of the stress and displacement fields under the loading conditions foreseen for the machine. A modal analysis was performed with the aim of calculating eigenvalues and eigenvectors useful to provide an assessment of the structural dynamic response. The most critical mode shapes and the related frequencies were calculated, and the potentially critical rotational speeds were quantified. Finally, the Peak Stress Method (PSM) was adopted to quantify the fatigue resistance of the most critical weldments and an infinite fatigue life was assessed for the most critical one. The design of the machine, which is currently under manufacturing, was validated by the structural analyses presented here.

Research and modeling of force fighting equalisation for aircraft rudder’s triple active actuation system

AbstractThis paper presents a new approach to force fighting equalisation in a redundant active-active-active rudder actuation system that is used for the primary flight control system of a turboprop regional aircraft. The related coupled problem of force fighting scenario, and the hydraulic architecture of electronic-hydrostatic actuator (EHA) are analysed, the mathematical model of the EHA system is built. The virtual test bench is designed to evaluate the performance of the force fighting equalisation strategy. The proposed methodology is tested on an iron bird test rig. The physical experiment shows that the fighting force is minimised under all flight conditions, meets the low cost requirement and can be a very reliable system. The proposed methodology can be applied to other types of aircraft’ flight actuation systems.

Simulation of Runway Irregularities in a Novel Test Rig for Fully Electrical Landing Gear Systems

The E-LISA research project, under way within the Clean Sky 2 framework, has the objective of developing an innovative iron bird dedicated to executing tests on the landing gear of a small aircraft transport equipped with an electro-mechanical landing gear and electrical brake. Such tests include the simulation of complete landing procedures under different operating conditions such as runway friction, presence of periodical defects along the runway, variable aircraft weight, and approach speed. To this end, the iron bird requires novel solutions in both its architecture and its control scheme. This paper details an innovative solution that is being implemented in the E-LISA iron bird to enable the execution of tests on a landing gear, reproducing the effects of any type of runway irregularity. First, the rig architecture is presented in detail, with particular care toward the hybrid position/force control system that manages its operations. Then, a simulation model is introduced with the objective of verifying the control system stability and the test rig capability to reproduce on the test articles the effects produced on the landing gear leg of periodical runway irregularities. Simulations results are presented, highlighting the stability of the proposed control scheme and providing a preliminary assessment of the system performances.

Layout and testing of a serial hybrid electric powertrain for a light twin demonstrator platform

The Project “RS hybrid 1.0” funded by the LuFo Program of the German BMWi is being executed in order to develop and investigate a serial hybrid electric powertrain to be used in a light twin aircraft, that could be exclusively operated on two electric motors. The powertrain includes a generator system, that provides energy to all power sinks like propulsors, batteries and also covers the low voltage demand of the aircraft. In the frame of this project, all necessary components are developed including the electric propulsion units, the hybrid generator system, battery modules, and DC-Link and associated subsystems.Everything is assembled in an iron bird testbed to be able to run the powertrain in an isolated fashion, to screen for potential issues and to measure operational data. Furthermore, a comprehensive control logic for the overall system and safety management of the powertrain is being developed and tested.

ENIGMA—A Centralised Supervisory Controller for Enhanced Onboard Electrical Energy Management with Model in the Loop Demonstration

A centralised smart supervisor (CSS) controller with enhanced electrical energy management (E2-EM) capability has been developed for an Iron Bird Electrical Power Generation and Distribution System (EPGDS) within the Clean Sky 2 ENhanced electrical energy MAnagement (ENIGMA) project. The E2-EM strategy considers the potential for eliminating the 5 min overload capability of the generators to achieve a substantial reduction in the mass of the EPGDS. It ensures optimal power and energy sharing within the EPGDS by interfacing the CSS with the smart grid network (SGN), the energy storage and regeneration system (ESRS), and the programmable load bank 1 secondary distribution board (PLB1 SDU) during power overloads and failure conditions. The CSS has been developed by formalizing E2-EM logic as an algorithm operating in real time and by following safety and reliability rules. The CSS undergoes initial verification using model-in-the-loop (MIL) testing. This paper describes the EPGDS simulated for the MIL testing and details the E2-EM strategy, the algorithms, and logic developed for the ENIGMA CSS design. The CSS was subjected to two test cases using MIL demonstration, and based on the test results, the performance of the ENIGMA CSS is verified and validated.

Modeling and Control of a Modular Iron Bird

This paper describes the control architecture and the control laws of a new concept of Modular Iron Bird aimed at reproducing flight loads to test mobile aerodynamic control surface actuators for small and medium size aircraft and Unmanned Aerial Vehicles. The iron bird control system must guarantee the actuation of counteracting forces. On one side, a hydraulic actuator simulates the hinge moments acting on the mobile surface due to aerodynamic and inertial effects during flight; on the other side, the actuator to be tested applies an active hinge moment to control the angular position of the same surface. Reference aerodynamic and inertial loads are generated by a flight simulation module to reproduce more realistic conditions arising during operations. The design of the control action is based on a dynamic model of the hydraulic plant used to generate loads. This system is controlled using a Proportional Integral Derivative control algorithm tuned with an optimization algorithm taking into account the closed loop dynamics of the actuator under testing, uncertainties and disturbances in the controlled plant. Numerical simulations are presented to show the effectiveness of the proposed architecture and control laws.

Pengembangan Model Bisnis Halal Logistik Transportasi Berbasiskan Business Model Canvass (BMC)

The basic concept of general logistics and halal logistics are actually the same, the difference is that halal logistics is carried out by ensuring that processes in the supply chain separate halal cargo from non-halal cargo. This needs to be done to avoid cross-contamination and ensure that as long as the logistics system of the product is guaranteed halal, therefore halal logistics can be expressed as the application of the halal concept throughout the supply chain activities of suppliers, manufacturing, warehousing, transportation and product distribution to ensure the halal status of a product. If this is done, it will produce halal logistic output according to the standards of the customer's wishes.
 The research will be carried out through interviews and surveys, the results will be used to identify business processes and find out what business activities are carried out and who are the business actors involved, from the business process a business model is then created to develop ordinary logistics to halal logistics based on a Business Model. Canvass (BMC). The Business Model Canvass (BMC) consists of 9 elements, namely customer segments, value propositions, channels, customer relationships, revenue streams, key resources, key activities, key partnerships and cost structures.
 The result of this research is to obtain a canvas-based halal logistics model that can be applied at PT Iron Bird, which is divided into 4 categories, namely: 1) Customers who have potential in halal logistics are industries engaged in fast moving, consumer goods, retail. , raw material and pharmacy 2) Value propositions, namely offers to customers regarding delivery that guarantees halal products, distribution to return goods or return, segregation for Less than Truck Load (LTL), re-packaging for contaminated goods, labels and documents halal, cleaning units according to standards, completeness of safety, transparency and trust, on time delivery, and costs in accordance with the services provided 3) Resources by managing main resources through a special team to handle contaminated goods, availability of vehicles, services provided , packaging for contaminated goods and labels and documents h alal 4) Financial through the services provided. Key Performance Indicators (KPI) in accordance with halal logistics standards which consist of: Quality, Time, Cost and Risk.

Design of iron bird for a regional jet aircraft

A regional jet’s iron bird was built for trouble shooting and design improvement of its airborne system. Modular design architecture and overall plan for the iron bird were proposed, and structure of the test rig, main tested systems, relevant supporting test systems and test programs were described. Besides, as one of the most critical airborne systems, NLG loading system was chosen for deep research; its mathematical model was built and analyzed in detail. Test results of hydraulic system’s main parameters were given. The whole iron bird provided important guarantee for system testing and continued design improvement. Also, test validation level for multi systems integration and fault diagnosis level of airborne system were improved.

DEVELOPMENT OF NUMERICAL PLATFORM FOR AIRCRAFT SYSTEMS SIMULATION

This paper discusses the development of a numerical simulation platform that can be used for representing the principal works of aircraft systems. The platform consists of some parts each of which is intended to replicate the operation of a system implemented in a modern aircraft, such as hydraulic line, electrical system, landing gear system, control system, etc. The platform is intended to be a tool for modeling and analyzing the operation and performance of certain systems configuration. To some extend the platform can be viewed as a virtual Iron Bird System. Iron Bird is a term representing a platform for simulating the works of aircraft systems using real components, which is very important for aircraft system development. At this stage, the numerical platform will only involve some sub-systems, namely main hydraulic line, control surface actuation, landing gear, and control system. These sub-systems are chosen to be the basis for further development where other sub-systems will be added and integrated to the platform.Keywords—Aircraft System, Numerical Simulation, System Analysis

Integrated Navigation, Guidance and Control System and Validation

The navigation, guidance and control (NGC) system of Reusable Launch Vehicle – Technology Demonstrator (RLV-TD) is the most complex system ever flown in ISRO’s launches. It includes a navigation system employing traditional inertial navigation system along with global positioning system aiding and radar altimeter, ceramic servo accelerometer package, angle of attack-based control, different control systems, including secondary injection thrust vector control, reaction control system and aero control surfaces. Closed loop simulations of integrated NGC system of RLV-TD are of utmost importance to ensure mission success by assessment of system performance in nominal and off-nominal flight conditions. Validation is achieved through progressive evaluations in different levels of integrated simulation, namely autonomous simulations, software in loop simulation, on-board processor in loop simulation, hardware in loop simulation and actuator in loop simulation using Iron Bird test facility. This article discusses the overall NGC system, challenges faced during the realization of the simulation test bed, including system design to validate the new on-board elements, commissioning of Iron Bird facility and validation through various phases of simulation. The outcome of these simulations played a crucial role in bringing about improvements and helping in the evolution of the on-board system to the final configuration, ensuring the success of the mission.

A review of electromechanical actuators for More/All Electric aircraft systems

Conventional hydraulic actuators in aircraft systems are high maintenance and more vulnerable to high temperatures and pressures. This usually leads to high operating costs and low efficiency. With the rapid development of More/All Electric technology, power-by-wire actuators are being broadly employed to improve the maintainability, reliability, and manoeuvrability of future aircraft. This paper reviews the published application and development of the airborne linear electromechanical actuator. First, the general configuration, merits, and limitations of the gear-drive electromechanical actuator and the direct-drive electromechanical actuator are analysed. Second, the development state of the electromechanical actuator testing systems is elaborated in three aspects, namely the performance testing based on room temperature, testing in a thermal vacuum environment, and iron bird. Common problems and tendencies of the testing systems are summarized. Key technologies and research challenges are revealed in terms of fault-tolerant motor, high-thrust mechanical transmission, multidisciplinary modelling, thermal management, and thermal analysis. Finally, the trend for future electromechanical actuators in More/All Electric Aircraft applications is summarized, and future research on the airborne linear electromechanical actuators is discussed.

Dynamic System Transfer Function Identification Based on the Experimental Results

The paper deals with identifying linear dynamical systems from the experimental data obtained through applying the test signals to the system. The paper objective is to determine both the form and the coefficients of the transfer function retrieved from the hodograph samples experimentally at bench test. The order of the frequency transfer function of the system being identified was assumed to be unknown. It was expected that in obtaining the frequency characteristics of a real system there would be noise during the experiment as a result of which the points of the experimentally obtained hodograph would be randomly shifted. As a model, a certain transfer function of the system was adopted. The authors proposed to find a solution of the identification problem in the class of hodographs specified by the model of the system. The search for unknown coefficients of the transfer function of the system model is carried out by minimizing a proximity criterion (measure) - described and published earlier by one of the authors - between the experimentally received system hodograph and the system model on an entire set of the experimental points of the system hodograph and the hodograph of the system model. The solution of linear dynamic system identification from the frequency hodograph was reduced to solving a system of equations of the system model frequency transfer function that is linear with respect to unknown parameters. The proposed identification algorithm allows us to determine the order of the frequency transfer function of the identified system from the experimentally obtained samples of the frequency hodograph of the system. For dynamic systems of the fifth order at most there is software developed to simulate the process providing the pseudo-experimental data with random errors and determining the parameters of such systems. A computational experiment has been carried out to evaluate the error with which the proposed algorithm determines the parameter values of the system to be identified. The illustrative computational experiment has shown that using the proposed algorithm for identifying a linear dynamic system from the frequency hodograph the error in determining the coefficient values of the frequency transfer function of the system is comparable with a range of measuring error in the experimental samples of the hodograph of this system. In known sources on identification of linear dynamic systems there is no method of identification this publication describes. This identification method of linear dynamic systems can find application in experimental testing, verification tests in situ and iron bird tests for vehicles of various purposes.

Clearance of Flight-Control-System Software with Hardware-in-Loop Test Platform

The Indian Light Combat Aircraft has flown more than 2000 flights, including trainer and naval variants, without encountering any major faults in the flight safety-critical fly-by-wire control software. This is partly due to the stringent quality control and rigorous testing of the control-law and air-data-system algorithms carried out on various ground platforms before flight. One of these ground test platforms is the hardware-in-loop test platform (Iron Bird). The processing of tolerance bounds to define the pass/fail criteria is an algorithmic development. It guarantees the correctness of the modules, if the set of inputs generates a set of outputs within processed tolerance bounds. This paper presents the philosophy behind the design of test cases and the tools developed to evaluate the control-law and air-data-system modules on the Iron Bird platform, and the procedure to clear the test results. The computation of tolerance bounds and algorithms for their processing have been evolved over a period based on several criteria, testers’ experience, and the experience gained during various levels of testing of air-data-system and control-law algorithms. This process yielded excellent results, and is accepted as a formal clearance methodology for the onboard safety-critical fly-by-wire system software.

Flight control iron bird based on passive electric‐hydraulic servo loading system

PurposeThe purpose of this paper is to develop a novel type of full‐size flight control iron bird based on a passive electronic hydraulic servo loading system.Design/methodology/approachOn the basis of mathematical modeling of passive loading system math model, the detailed design process of the flight control iron bird is presented. Subsequently, the system digital simulation and physical verification are also given.FindingsExperimental results show that the proposed approach can reduce the redundant forces and improve the system dynamic and force‐tracking accuracy.Practical implicationsThis newly‐developed flight control iron bird system has been successfully applied in the flight control system design of some fighters.Originality/valueThe proposed approach for flight control iron bird is new and significant for the design of fighter flight control systems.

The Iron Bird for the Fairchild-Dornier 728

A full size representative system integration test rig (Iron Bird) for the Fairchild-Dornier 728 regional jet has been designed and built. The 728 is a full fly-by-wire aircraft without mechanical back-up and is the benchmark for system integration in its class. The primary focus of Iron Bird testing is on flight controls, landing gear and hydraulics; other aircraft systems are installed for support. To reproduce in-flight aerodynamic loads, a hydraulically powered computer-controlled loading system is employed. The rig is not only used to minimize the development risk by testing fully integrated systems well in advance of the first test aircraft, as in previous programs, but also to unload ground and flight testing to the greatest extent possible as well as to conduct certification testing. A description of the Iron Bird structure and the aircraft systems' integration into the rig is given. An overview is provided of the rig's mechanical and electrical design as well as of its control and data acquisition system. The Iron Bird's capability to run in a closed loop configuration with the Engineering Simulator is highlighted. The main test targets are pointed out and results to date are presented. An outlook with respect to possible future testing and the extension of the capabilities of the Iron Bird facility is provided.