This paper was produced for the 2019 NAFEMS World Congress in Quebec Canada

Resource Abstract

A high lift device is a system used to control the lift in an aircraft by actuating the flaps and slats. Importance of high lift device is to control the lifting force even when the aircraft speed decreases; hence these devices are vital in aircraft take-off and landing stages.



Earlier only experimentation techniques and various simulation techniques such as computational fluid dynamics were used to study the performance of these devices. This led to major challenges in studying the characteristics of each sub units, resulting in high lead time and finally high cost to study and develop a system. It is much simpler and easier to study and understand the complex behaviour of various systems and sub-systems associated within the mechanism by the application of System level Block Design using a customized set of block libraries.



SYSTEM Level Design and Simulation is chosen to study the behaviour and performance of each sub-units of high lift device in order to make effective decision and transforming the developed system model in to an effective experimental Test RIGS. MSC’s EASY5, a 1-D Multi-Physics System Simulation software is used to model and simulate the hydraulic circuit of the test rigs for aircraft high lift devices.



The Hydraulic circuit consists of a drive unit and a load unit. The drive unit consists of a Flow Control Valve, Accumulator, Servo Valve and a Hydraulic Motor called the Power Drive Unit, which is connected to the load unit hydraulic motor through a drive shaft. Driving side utilizes a Servo valve to control the flow of hydraulic fluid to the hydraulic motor when driving the system. Loading side utilizes a Proportional Pressure Control Valve to control the upstream pressure thereby loading the motor to generate required torque. A closed loop of PID control is used to control the flow of hydraulic fluid by Servo Valve in driving side and Pressure Control Valve in loading side.



Simulation results proved that the required speed (RPM) of the Drive side motor can be controlled by the flow of fluid from the Servo Valve to the drive side motor and achieve the required Revolution position of the motor. Similarly the Torque generated by the Loading Side Motor based on the upstream pressure created to control the load motor. Hence the analysis gives us flexibility of modelling and analysing the performance of hydraulic sub systems at various loading conditions and finally helps us to understand the behaviour of the system at the stage of development itself.