the aristotel project aircraft and rotorcraft pilot...

The ARISTOTEL project

Aircraft and Rotorcraft Pilot

Couplings Tools and Techniques for Alleviation and Detection

http://www.aristotel-project.eu/

General presentation

Workshop A/RPCs Milano March 9, 2011 2

Background of ARISTOTEL

ARISTOTEL = Aircraft and

Rotorcraft Pilot Couplings

Tools and Techniques for

Alleviation and Detection

Collaborative project funded

under the European

Communitys 7th Framework

Programme Detail from The School of Athens, Raphael

Aristotel, Aristotle,

Aristoteles(384 BC 322 BC)

Greek philosopher, a student of

Plato and teacher of Alexander

the Great.

http://en.wikipedia.org/wiki/File:Sanzio_01_Plato_Aristotle.jpg

Workshop A/RPCs Milano March 9, 2011

Facts and figures

Acronym: ARISTOTEL - Aircraft and Rotorcraft Pilot Couplings Tools

and Techniques for Alleviation and Detection

Grant Agreement: 266073

Instrument: CP FP

Total cost: 3,843,228.30

EU funding: 3,003,652

Call: FP7AAT2010RTD1

Start date: 01.11.2010

End date: 01.08.2013

Duration: 36 months

Technical domain:

Ensuring Customer Satisfaction and Safety

Website: http://www.aristotel-project.eu/

3


The ARISTOTEL Consortium

4

Technische Universiteit Delft - Coordinator

Wytwornia Sprzetu Komunikacy Jnego PZL-

Swidnik Spolka Akcyjna

Office National d'Etudes et de Recherches

Aerospatiales

Politecnico di Milano

Universita degli Studi Roma Tre

The University of Liverpool

Stichting Nationaal Lucht- en

Ruimtevaartlaboratorium

SC Straero SA

Federal State Unitary Enterprise The

Central Aerohydrodynamic Institute

named after Prof. N.E. Zhukovsky

European Research and

Project Office GmbH


EU set a joint initiative to cut

aviation accidents by 80% in 2020

A/RPCs are still a matter of high

concern for safety.

Modern designs seem

even more sensitive to

A/RPCs

Rotorcraft RPCs are

significantly more

problematic than

aircraft APCs.

We hardly possess

guidelines for

designing A/RPCs

free configurations.

The understanding, controlling and suppressing of pilots involuntary participation is a demanding problem for actual aircraft with high bandwidth servo hydraulic actuation systems and enlarged operational ranges.


The ARISTOTEL key problems

The

ARISTOTEL

project

KEY PROBLEM 1

Lack of

understanding what

A/RPC is

KEY PROBLEM 2

Lack of specific

A/RPC pilot models

KEY PROBLEM 5

No proper simulator

practices to unmask

A/RPC

KEY PROBLEM 4

No reliable A/RPC

criteria

KEY PROBLEM 6

No coherent design

guide for A/RPC

KEY PROBLEM 3

Lack of proper

A/RPC vehicle

models


The ARISTOTEL ambition

The

ARISTOTEL

project

OBJECTIVE 1

Develop

understanding &

definition of A/RPC

OBJECTIVE 2

Develop advanced

pilot models for

A/RPC analysis

OBJECTIVE 5

Develop protocols for

simulator training

OBJECTIVE 4

Develop, extend,

improve current

A/RPC criteria

OBJECTIVE 6

Develop coherent

design guide

OBJECTIVE 3

Develop advanced

vehicle models for

aircraf/rotorcraft


The ARISTOTEL Work Plan

8

WP1 Anatomy of APC/RPC

WP2 Rigid body RPC WP3 Aero-servo-elastic A/RPC

WP4 Testing and validation for A/RPC

WP5 Design guidelines and methodologies

for A/RPC prevention

WP6 D

isse

min

ati

on &

Explo

itati

on

WP7 M

anagem

ent


What is A/RPC?

Fixed and rotary wing pilots alike are familiar with potential

instabilities or with annoying limit cycle oscillations that arise

from controlling aircrafts with high response actuation

systems.

Pilot

Flight control system

Aircraft/Rotorcraft

A/RPC (PIO/PAO) =

"Inadvertent, sustained

aircraft oscillations which

are a consequence of an

abnormal joint enterprise

between the aircraft and

the pilot"

(McRuer et al., 1997)


What is A/RPC?

Definition developed in ARISTOTEL:

"An Aircraft- or Rotorcraft-Pilot Coupling (A/RPC) is an

unintentional (inadvertent) sustained or uncontrollable

vehicle oscillations characterized by a mismatch between the

pilots mental model of the vehicle dynamics and the actual

vehicle dynamics. The result is that the pilot's control input is

out-of-phase with the response of the vehicle, possibly

causing a diverging motion."


Aircraft/Rotorcraft Pilot couplings

with PIO

Physics:

A/RPCs occur when the pilot inadvertently excites divergent

vehicle oscillations by applying control inputs that are in the

wrong direction or have phase lag. Since active involvement in the

control loop is occurring, A/RPCs will cease when the pilot

releases the controls, stops control motion or changes control

strategy.

Examples at helicopters:

Excitation of low -damped main rotor regressive inplane mode by

cyclic stick inputs resulting in body roll and pitch aircraft

vibrations.

Excitation of low frequency pendulum mode of external slung

loads by delayed collective and/or cyclic control inputs due to

couplings of the load dynamics via elastic cables.

11

Pilot induced oscillations


Well known Problems of Unintended RPC

at helicopters

Inplane Forces Vertical Forces, Torque

Source: Cyclic control inputs

Problem: Resonance excitation of inplane

regressive/blade bending modes

Blade strength limits

Source: Collective control inputs

Problem: Resonance excitation of tailboom

bending and drive train modes,

respectively

Comfort & strength limit

Source: Eurocopter, Garteur work PIO

12


Physics:

A/RPCs are the result of involuntary control inputs of the pilot in the loop

that may destabilize the aircraft due to inadvertent man - machine couplings.

Since passive involvements by the pilots biodynamic response to vibrations

occur, these oscillations are generally much more dangerous because releasing

the controls may be impossible.

Examples at helicopters:

Destabilization of the main rotor blade bending torsion motion at high rotor

loadings and flight speeds during manoeuvres by stall effects results in

airframe vibrations which may be amplified by unintended cyclic stick inputs

of the pilot.

Destabilization of low-damped main rotor engine drive train modes

aggravated by pilot assisted collective control inputs.

Augmentation of transient airframe bending oscillation by feedback type

couplings of the airframe structure by the main rotor via the actuation system

assisted by collective and/or cyclic control inputs.

Aircraft/Rotorcraft Pilot couplings

la PAO

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Pilot assisted oscillations


Division of A/RPCs

A/RPCs in Flight Mechanics

Associated with flight mechanical frequencies

Related to high control sensitivities (e.g. about roll axis)

Attributed to an overlap of guidance and control task

A/RPCs in Dynamics/Aeroelastics

Associated with structural dynamics or aeroelastic

resonances

Supported by high bandwidth servo-hydraulic control

systems

14


Simulators

TUD

LIVERPOOL

NLR

TSAGI

Helicopters Fixed wing Bio-dynamical tests

4 test campaigns for bio-dynamical research and

4 test campaigns for simulators have been planned.


Multitude of configurations

Relation between the next generation cockpit control configurations and pilot-vehicle interaction for prevention of large transport aircraft APC and rotorcraft RPC

Fly-by-wire sidestick flight deck Future large transport aircraft Conventional wheel/column flight deck


CE HO

CD

PLF NMS

CNS

Example of Biodynamic Feedthrough Tests

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Biodynamic feedthrough (BDFT) = the phenomenon where vehicle accelerations can cause involuntary pilot control inputs

CD : Control Device

CE : Controlled Element

PLF: Platform

HO : Human Operator

NMS : Neuromuscular System

CNS : Central Nervous System


Example of Biodynamic Feedthrough Tests

Recent results of BDFT tests: BDFT is task dependent

Biodynamic feedthrough Neuromuscular admittance

stiff

compliant

low feedthrough

high feedthrough

Joost Venrooij et. Al. (2010)

Ascent from the study of particular phenomena

to the knowledge of essences

Like Aristotle, we hope to find the "universal"

in particular things - the essence of things -

ARISTOTEL

the aristotel project aircraft and rotorcraft pilot...

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