Real Time Simulation of Flexible Aerospace Vehicles Using ...€¦ · Real Time Simulation of Flexible Aerospace Vehicles Using Simulink and RT-Lab Yadunath Gupta, IIT Kharagpur Pulak

Real Time Simulation of Flexible Aerospace Vehicles Using Simulink and RT-Lab

Yadunath Gupta, IIT Kharagpur

Pulak Halder, Research Centre Imarat

Siddhartha Mukhopadhyay, IIT Kharagpur

23-04-2015 1© 2015. All Rights Reserved

Agenda

• Flexible aerospace vehicles

• Controller design

• Challenges

• Strategy

• Simulation and results

• Conclusion


Flexible Aerospace Vehicles

• Definition: Vehicles that undergo structural deformation during flight

• High length to diameter ratio

• Aerodynamically more efficient

• Lower radar visibility


Effects of Flexibility

• Corrupts the feedback signals from sensors

• Vibration frequencies can interfere with control frequencies.

• May lead to self excited divergent oscillations

Proper controller design and simulation of vehicle flight dynamics is necessary to ensure stability


Controller Design

• Gain stabilization for high frequency modes

• Phase stabilization for lower frequency modes


Non-Real Time vs Real Time Simulation

• Non-real time:

– Generally used for validation of algorithms

• Real time:

– Essential for validation of controllers which are designed using phase stabilization.

– Can simulate effects of computational delays

– Enables testing of hardware components


Challenges

• Complexity and order of the model is large

• High computational load

• Model compatibility with real time simulator

• Support for IO cards / communication interfaces in hardware-in-loop simulation

• Monitoring and debugging


Strategy

• MATLAB and Simulink

• RT LAB

• Distributed architecture

• Multi-rate simulation


Tactical Aerospace Vehicle and its Model in MATLAB®/Simulink

23-04-2015 9

Atmospheric ModelVehicle Dynamics

Model (6DoF)Guidance & ControlNavigation

© 2015. All Rights Reserved

Control SurfaceWing

Navigation Guidance & Control

Motor (propulsion)

Navigation Guidance ControlAirframe &

Propulsion

Vehicle

Dynamics

~

Vx~

X~

Acceleration, Rates

ActuatorPlant

Advantages:

Conversion from Non Real-time to Real-Time is very easy

Easy to Implement Communication interfaces (MIL std 1553B, SharedMemNet, ADC/DAC etc.)

Easy to trace the signal, Introduction of disturbance

Validation of model developed by external Agencies (Academic institution/Collaborating Org)

has become easier (Plug & Play).

Vehicle Dynamics Model

23-04-2015 10

PY_Bending

3

Mslp_INS _RGP_PY

2

axyzpqrdot _RFlex

1

In1

In2Out1

-1

1/57 .3

Sarea

1/57 .3

Rigid _6DOF MODEL

delta_p

delta_y

delta_r

pa

alpha

beta

dp

mac

Phi_actual

time

qr_RFlex

ThMscgIyyIxx

axyz _pqrdot_R

FLEX _6DOF_Model

Thrust

mass

xcg

Iyy

axyz _pqrdt_Rigid

tm

Alp_beta

AlphaT

mac

DynPr _sArea

Delta_PY

Vel_b

axyzpqrdot _RFlex

Mslp_INS_RGP_PY

qr_RFlex

PY _Bending

Vel_b

6

time

5

Atmos_para

4

delta _r

3

delta _p

2

delta _y

1

Rigid Body Model

Flexibility Model


Flexibility Model

23-04-2015 11

PY_Bending

4

qr_RFlex

3

Mslp_INS _RGP_PY

2

axyzpqrdot _RFlex

1

Vel_b1

12

Eng_Acc _Gyro _modfLoc

omega_flex _col

gen_mass_col

gm_dot_col

tm _col

xcor

xcna

phy 1

phydsh 1

phy 2

phydsh 2

phy 3

phydsh 3

tm

Mshp_Mslp_TE

Mshp_INS

Mslp_INS

Mslp_RG

wz_GM_GM_dt

rphy

rphydsh

ModeShpSlp _calc

Mslp _INS

Mslp_RG

FCoe _qfdt

FCoe _ayf

FCoe _qyddt

xcg_E_T

wz_mz_mz_dt

Mshp _INS

Mshp _Mslp_TE

Flex _Yaw_Plane

ay _R

r_dot_rigid

Thrust

Vx

Vyb

mass

Izz

beta

deltaY

r_RFlex

fy _ins_rdot_cg

Mslp_INS_RGP_Y

YawBending

Flex_Pitch _Plane

az_R

q_dot_rigid

Thrust

Vx

Vzb

mass

Iyy

Alpha

deltaP

fz_ins_qdot_cg

Mslp_INS _RGP_P

q_RFlex

PitchBending

rphy

rphydsh

mac

QS

alphaT

Vel_b

xcna

mach_col

Cna1

Cna2

Cna3

xcgE

FCoe_qyddt

FCoe_ayf

FCoe_qfdt

force _coeff

xgimb

Cna2

Cna1

gm _dot _col

gen _mass_col

omega _flex _col

mach _col

Cna3

Eng _Acc_Gyro_modfLoc

xcna

phydsh 3

phy 3

phydsh 2

phydsh 1

phy 2

phy 1

xcor

tm_col

sitvl

xcna

Vel_b

12

Delta _PY

11

DynPr_sArea

10mac

9

AlphaT

8

Alp _beta

7

tm

6

axyz_pqrdt _Rigid

5

Iyy

4

xcg

3

mass

2

Thrust

1

Mode shape & slope ComputationFlexibility Rate & Lateral Acc. Computation in Pitch/Yaw plane

Force Coef. Computation


Pitch Plane Flexibility Model

23-04-2015 12

PitchBending

4

q_RFlex

3

Mslp _INS_RGP _P

2

fz_ins_qdot _cg

1

Vx

Alpha

Thrust

deltaP

qy

qy _dot

qy _ddot

qy

qy_dot

qy_ddot

Thrust

mt

Vy _dot_f -u

-u

-u

Thrust 1

3

TPZ 12

In Out

qy

qy_dot

qy_ddot

Thrust

delta_P

Iyy

Vy

r_dot_f

r_rdot

-K-

-K-

Flx_flag _P

Flx_flag _P

-K-

Flx_flag _P

Flx_flag _P

Flx_flag _P

Mslp _RG

Mslp_INS

Mshp_INS

deltaP

9

Alpha

8

Iyy

7

mass

6

Vzb

5

Vx

4

Thrust

3

q_dot _rigid

2

az_R

1

Generalized Coordinate

ComputationFlexibility Lateral Acc. Computation

Flexibility Rate Computation


Simulation Scenario

• Scenario of a flight test which failed due to excessive bending oscillations was reproduced

• Flight response of the launch vehicle with rigid body model and flexible body model was analysed

• Updated controller was validated


Vehicle Response with Rigid-Body Model


Vehicle Response with Flexible-Body Model


Vehicle Response with Flexible-Body Model and Updated Controller


Conclusion

• MATLAB and Simulink tools enabled to develop a complete model of the dynamics of a flexible aerospace vehicle

• RT LAB helped in real time simulation of the vehicle using Simulink models, with hardware in loop

• Block based modelling technique eased the process of debugging, monitoring and modifying the model, and allowed for flexible degrees of freedom to be added to the existing rigid body model


Thank you!


Documents

Real Time Simulation of Flexible Aerospace Vehicles Using ...€¦ · Real Time Simulation of Flexible Aerospace Vehicles Using Simulink and RT-Lab Yadunath Gupta, IIT Kharagpur Pulak