{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

ASE 370L Take Home Test 3

# ASE 370L Take Home Test 3 - ASE 370L Take Home Test 3 Drew...

This preview shows pages 1–3. Sign up to view the full content.

ASE 370L Take Home Test 3 April 29, 2010 Drew Rosecrans DCR544

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
Satellite Attitude Controller with Control Moment Gyros It is necessary to control the attitude of a satellite in space. Based on what the satellites’ purpose is, it may be useful to keep the satellite pointed toward Earth or out into space. There are several ways to control the attitude of an object in space, but for this problem a control moment gyro (CMG) is to be used. In this problem it is important to consider gravity gradient torques due to the variation of the earth’s gravitational field over the satellite. Also aerodynamic disturbances due to the atmosphere need to be accounted for. The simplified model of the spacecraft is given by = = - θsUs Gs 1Iys2 3n2Δ Where θs is the pitch angle, Us is the CMG input torque, = . Iy 0 2 kg∙m2 , = - Δ Iz Ix , = . Ix 0 1 kg∙m2 , = . Iz 0 01 kg∙m2 , and = . / n 0 0011 rad sec is the orbital angular velocity. For this problem it is desired that the satellite be pointed toward Earth, that occurs when θs = 0 , thus the desired pitch angle θds = 0 . Now the gravity gradient term is taken care of in the plant model Gs , it is represented by =- Tgg 3n2Δθs The CMG is a constant-rate flywheel mounted on a set of gimbals that is controlled by actuators. The simplified model for the CMG is = + Gas 15s 15 The aerodynamic disturbance is due to atmospheric drag acting on the satellite and creating a torque. We can view this torque as a disturbance because it is generally much smaller than the gravity gradient torque. This disturbance torque,
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

### What students are saying

• As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

Kiran Temple University Fox School of Business ‘17, Course Hero Intern

• I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

Dana University of Pennsylvania ‘17, Course Hero Intern

• The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

Jill Tulane University ‘16, Course Hero Intern