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Precision Control Autonomous Systems for NEO Mission Design

Precision Control Autonomous Systems for NEO Mission Design. Karl Williams Matthew Zimmer. Project Basis / Motivation. Asteroid mission has received a lot of attention in recent years Defense, economic and exploration purposes Current missions DAWN and HAYABUSA II (2014-15 Launch)

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Precision Control Autonomous Systems for NEO Mission Design

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  1. Precision Control Autonomous Systems for NEO Mission Design Karl Williams Matthew Zimmer

  2. Project Basis / Motivation • Asteroid mission has received a lot of attention in recent years • Defense, economic and exploration purposes • Current missions • DAWN and HAYABUSA II (2014-15 Launch) • Orbital control as not been demonstrated around objects of small diameters • 500 meter in diameter scale

  3. Let’s Look at an Example.

  4. Classifying the Problem • Need to determine regions of natural stability • Balance between complex gravitation, solar radiation pressure and third body perturbations • Which orbital parameters are needed such that our spacecraft stays in orbit for a longer duration of time disregarding external control

  5. Standardizing the Model • Running multiple simulations on different computers • Prone to error due to changing initial conditions • Asteroid characteristics • Epoch • Rotation • Gravity Model • Create a standard satellite model • Surface Area • Dry Mass • Fuel mass 25143 Itokawa(JAXA – 2005)

  6. Standardizing the Model • Custom Ion Engine Model • Maximum & Minimum Power • Specific Impulse • Mass Flow Rate • Based on existing 8 cm Ion Engine* *L3 Communications

  7. PID Control • Proportional, Integral, Derivative Control • Error Function: Current altitude vs desired altitude • Execution • Proportional – push based on error • Integral – constant summation (plus correction) of the error over the simulation • Derivative – monitors the position’s rate of change and helps to eliminate rapid fluctuations leading to overshoot

  8. Simulations • Interface Matlab and STK • Orbital Mechanics vs PID Control • Hohmann Transfer is useful for direct control • PID is useful for indirect control • Multiple simulations ran • Impulsive burns • Finite burns

  9. Questions? • We would like to thank: • Josh Johnson, Chris Church • Dr. Ron Fevig, Dr. William Semke • North Dakota Space Grant Consortium • UND Seed/Planning Grant for Collaborative Research, Proposal Entitled, “The Development of Predictive Control for Autonomous Systems” • NSF Grant #EPS-081442

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