Development of Guidance and Control System for Parafoil-Payload System

1. Development ofGuidance and Control SystemforParafoil-Payload System VVR Subbarao, Sc ‘C’ Flight Mechanics & Control Engineering ADE

2. Leading Edge Cell` Stabilizer Panels Suspension Lines Steering Lines Payload Parafoil-Payload System • Advantages • Sufficient glide and wind penetration • Low potential damage to payload • Fly aircraft at safe stand-off distance • Greater offset distance for given altitude • Differences with Aircraft • Flexible lifting surface • Centre of mass is suspended below canopy • Control is achieved by changing parafoil shape • No external power to push forward • Control Surfaces – 1 pair at the Trailing Edge • Symmetrical Deflection • Changes flight path angle and rate of descent • Asymmetrical Deflection • Generates turn Workshop on Mathematical Engineering

3. CADS NameControlled Aerial Delivery System Objective To demonstrate the technology for precise delivery of a payload of 500 kg using a Ram Air Parafaoil Workshop on Mathematical Engineering

4. Airborne Guidance &Control System` Task To develop Airborne Guidance and Control System to meet required CEP of 100m Followed Strategy • Phase I • Developing path control in 2-D plane on 80kg p/p system • To assess the control effectiveness of parafoil • To arrive the suitable guidance and control scheme • Phase II • Development of guidance and control scheme to make touch down within 100m CEP • Design of Energy Management Maneuvers • Extension of these CLAW for 300kg parafoil Workshop on Mathematical Engineering

5. Phase I

6. Issues • Simulation Model • Conventional 6 DOF equations do not hold • Multi-body dynamics • 4, 6, 9, 12 Degree-of-Freedom • Lifting surface is not rigid • Flexible canopy • Aerodynamic Data • Not available at the beginning • Data was generated semi-rigid canopy • Later data available only for 500kg parafoil • Stability and control derivatives • No rate derivatives • Data Generation Trials • Controlled from ground • Planned data generation trials • Developed 4 DOF model Workshop on Mathematical Engineering

7. DRU Analog RS 232 NMEA GPS Receiver PFCC BL 2120 Alt. Sensor Tx,Rx Heading Actuators On-Board Sub-Systems Pt & SB Lanyard Commands Tx, Rx Joy Stick Ground Sub-Systems Ground based Guidance and Control System Architecture • Issues • Vehicle state information • Sensors Mounting • Sensors selection Workshop on Mathematical Engineering

8. 4 DOF Mathematical Model • Assumption • parafoil-payload (p/p) load system as a single rigid body. • Simulates • the forward and downward translations • roll and yaw (turn) motions of the para-foil. • Does not required much aero data • Used • to finalize the implementation of control laws • In Hardware-In-Loop Simulation to close control loop • To design failure logics • Train ground pilot Workshop on Mathematical Engineering

9. Guidance and Control Scheme • Autonomous Mode • Two loop • Outer loop • Cross-track error minimization • Inner loop • Heading error minimization • Sensors • Main • GPS • Monitoring • Static Pressure • Compass Workshop on Mathematical Engineering

10. Handheld Terminal TX/RX  C BL 2120 RS 232 Para Flight Control Computer RS 232 Heading Sensor IAS Transducer Analog Altitude Transducer Analog Proximity Sensor RS 422 On-board DRU GPS Antenna Target Point Parachute Power Supply Port Lanyard Actuator Starboard Lanyard Actuator AG&CS Architecture Workshop on Mathematical Engineering

11. Phase II Workshop on Mathematical Engineering

12. Energy Management Maneuver • Objective • To ensure the touchdown within CEP • Selected Fig-of-Eight Maneuver for altitude management • Length of leg is fixed considering turn time Workshop on Mathematical Engineering

13. 300kg p/p system • Sluggishness response • No turn rate response up to 20% of differential command • No aerodynamic rate derivative data • Model derived from flight data Workshop on Mathematical Engineering

14. Challenges • Design of Guidance and Control Scheme • catering to high wind • Payload mass variations • Terminal Guidance for Soft Landing • Flight path can be influenced only with symmetrical deflection above 50% of total deflection • Turn and altitude control cannot simultaneously done • Sluggish Response • No Turn rate for command less than 20% of total command • Non-linear turn rate response against differential command • Gain Scheduling • Measuring wind magnitude and direction • Air speed measurement Workshop on Mathematical Engineering