ndi flight control
DESCRIPTION
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Flight Control Design using Nonlinear Dynamic Inversion
Dr. Om Prakash PhD. IIT Bombay M.Tech. IIT Kanpur [email protected]
Nonlinear Dynamic Inversion
• Nonlinear Aircraft dynamics are inverted based on measured states and inputs
• Cancels the original Aircraft dynamics of the system
• Replaces with desired Aircraft dynamics
• Used as feedback in control design
• Output should perfectly match the input
• Applicable to Highly maneuverable Aircrafts, Missiles, etc.
Nonlinear Aircraft Dynamics
Control Surface deflection
Aircraft States Aircraft Forces and Moments
Aircraft Forces and Moments dependent on
control surface deflection
Aircraft Forces and Moments independent of control surface deflection
Inverting above equation
Nonlinear Aircraft Dynamics Inversion
• Desired Aircraft Dynamics
Control Surface Deflection required to achieve demanded aircraft states
Desired Aircraft
Dynamics
Feedback Aircraft States
Commanded Aircraft States
SISO(Aircraft Pitch Axis) Dynamic Inversion Control
System Dynamics
System Dynamics Inversion
SISO(Aircraft Pitch Axis) NDI Control
• Longitudinal Dynamics
• Desired to control pitch rate q
Simplified 6DOF Aircraft Dynamics
Simplified representation
6-DOF Aircraft Dynamic Inversion
9-DOF PARAFOIL-PAYLOAD SYSTEM
9-DOF PARAFOIL-PAYLOAD EQUATIONS
• 9DOF EQUATIONS
Heading Tracking of Parafoil-Payload System
• Yaw rate inner loop equation
• Yaw Angle outer loop equation
Parafoil-Payload System Inner Loop Dynamic Inversion
• Yaw rate inner loop Inversion
• Inversion is
• Substituting this in above we get
Inner Loop inversion Block Diagram
Parafoil-Payload System Outer Loop Dynamic Inversion
• Yaw angle outer loop Inversion
• Inversion is
• Substituting this in above we get
Outer Loop Dynamic Inversion Block Diagram
Heading Tracking using Inner and Outer Loops
Longitudinal Missile Dynamics
Longitudinal Missile Dynamics Inversion
Longitudinal Missile Dynamics Inversion Result (Sungjin Cho et. al., 2002)
THANKS
End of Presetation