Transcript FF_FDR_ADCS
Why Zero-momentum? Type D. of F. Gravity inclination 0 cost Accuracy Low Low Spin Attitude Change Heat generation Can't change Small Components Other None Difficult Dual Spin 1 Nutation Bias Momentum For small Dumper Large Controled bias Weak from disturbance 2 momentum 3 High High Easy Mass Wheel communication Sat. Bias+Roll Reaction Weak from disturbance. For Wheel communication Sat. Don't use Momentum Bias+Roll/Yaw LEO Reaction Strong from disturbance For Large Sat. LEO Zero momentum Wheel is OK Zero momentum: Each axis is independent. It is easy to control. I don’t know if we need one, but an introduction slide with your names and hours worked might be a good idea. It should be included somewhere in the presentation. Make sure to explain this slide and the requirements that needed to be met and how they were met. 1 Attitude Determination Use bullet points to separate ideas. Do this through out the presentation on all slides. Clarify that attitude is fixed and that the satellite always points in the same direction without attitude control. Get rid of the question mark before the statement. I am not sure what this question is. Fixed pointing the same direction ?Point exact center? Maybe rephrase to, Does the camera always point at the center of the shuttle? Front View x y 2 z Pointing Direction Make sure to explain the figure and what it represents. Put conditions from orbit control team into Joe’s code. 3 Pointing Error Make sure to explain this figure as well and what it represents. Worst case: Maximum pointing error is about 33 degrees. 4 Case when is larger than Field of View, angle, r This slide is a little confusing because it refers to multiple Multiple Camera cameras but we are not using multiple cameras. If you are saying that the size requirement limits the use of multiple cameras, explain how we will rotate to get the largest field of Length of the shuttle view (The longest) To get large , we should use multiple cameras. It (the satellite?) is easy to control, and need more space for camera. Especially when 33 5 Single Camera Case when is smaller than Consider making the figure a bit larger. Field of View, angle, r Worst case: r 220[m] 18.6 6.195 Because of small , we have to change the direction. Need more accurate sensors. 6 Multi VS Single camera • Multiple camera Easy to control Need to space to put camera Need more space than is available for multiple cameras. • Single camera Need to control to point the shuttle. (Explain later) 7 Disturbance G r Aerodynamic torque: Taero rcp Faero a v Solar Radiation Pressure Torque: Tsolar rcp 1 K A i t 2 ˆ I rˆ Gravity-Gradient Torque: T 3 n r gravity y Magnetic torque: Tmagnetic M B G r a Ttotal,dist Taero d Tgravity Tsolar Tmagnetic i 0.0373 e 3 10 n 0.5070 Nm t Is c Tgravity 0.4521 8 Changing Orbit Requirement 89.9 T from 1 to 2 Orbit 1: Blue Orbit 2: Red 90 min 4 Pointing thrust req 89.9 deg/s t 89.9 90 min 4 0.0666 deg/s 9 I’m not sure that this diagram is correct. We might not have time to change it however. I thought this angle was 89.9 deg 89.9 72 m | | 0.0007 r 6731 km sin A sin B sin C sin 0.0007 sin a b c 72 6731000 89.9 10 Requirement for pointing camera Pointing requirement Pointing camera 6.195096 Pointing requiremen t : 1 5 5 1.2390192 shuttle FOV : 6.195096 What does FOV stand for?, writing it out may help with clarity. Also consider making the diagram larger. 11 Simulation There should be some comments on this slide explaining what this figure means or how it is relevent. 12 Reaction wheel Make sure to explain figure and how it is relevant. T 40 m Nm ReactionWheelsR03 produces 50mNm R03 (Sun space) 13 Attitude sensor Accuracy of sensor : req 1 req 10 0.1239 This slide is kind of bare. Maybe add a picture or two and explain how the star tracker will work and what requirement it satisfies. Star tracker 14 Conclusion • Each equipment is satisfied with our requirements. Maybe list each requirement that was satisfied and how it was satisfied 15