Accounting requirements for aeroservoelastic stability of maneuverable unmanned aircraft during the stage of electromechanical rudder drive design

Aviation technics and technology


Turkin I. K.1*, Kondrashev G. V.2**

1. Moscow Aviation Institute (National Research University), 4, Volokolamskoe shosse, Moscow, А-80, GSP-3, 125993, Russia
2. State Machine Building Design Bureau «Vympel» by name I.I. Toropov, 90, Volokolamskoe shosse, Moscow, 125424, Russia



The purpose of this study is to propose an electromechanical rudder drive design method. Main objective of this method is to determine critical values of rudder drive design parameters on stage of conceptual design and reduce time expenses required for experimental obtaining of the aeroservoelastic (ASE) stability margins.

A mathematical modeling approach has been chosen to solve the rudder drive design problem. The rudder drive model has been developed in MATLAB/Simulink environment corresponding to block diagram of real electromechanical drive. The frequency response function (FRF) has been measured from real electromechanical rudder drive and then compared with calculated FRF obtained from Simulink to validate the developed rudder drive model.

During the validation process it is found that the mathematical model of a rudder drive reliably reproduces the characteristics of the real drive and thus can be used to preliminary estimate the ASE stability margins.

The developed model has the potential for further improvement, for example to include new tasks such as rudder drive stability regions formation for several design parameters. Further development of the model should be directed towards the detailed backlash simulation in reduction drive. To solve this task reducer should be represented as two (or more) gear wheels which are moving separately from each other in backlash.

The design method described in this study can help to replace a part of the experimental studies with mathematical modeling. Also with the help of this approach it is possible to reduce the risk of ASE instability in the final stages of design, thereby avoiding costly changes to the automatic control system and rudder drives to eliminate shortcomings.


aeroservoelastic stability, unmanned aircraft, electromechanical rudder drive, conceptual design


  1. Moskalenko V.V. Elektricheskii privod (Electric drive), Moscow, Akademiya, 2007, 368 p.
  2. Firago B.I. Teoriya elektroprivoda (Electric drive theory), Minsk, Tekhnoperspektiva, 2004, 527 p.
  3. Pedora A.P., Smyslov V.I. Issledovanie aerouprugoi ustoichivosti manevrennykh bespilotnykh letatel’nykh apparatov (Investigation of aeroelastic stability maneuverable unmanned aircrafts), Trudy TsAGI, 2005, no. 2669, 260 p.
  4. Turkin I. K., Kondrashev G.V. Elektronnyi zhurnal «Trudy MAI», 2011, no.49, available at: (accessed 27.12.2011).

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