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ESA Document - Emits - ESA

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s<br />

3-axis<br />

accelerometer<br />

3-axis rate gyro<br />

altimeter<br />

LIDAR, camera<br />

ASTOS: Trajectory optimizer<br />

α, µ commanded<br />

Rate limiters<br />

Ρ,Π, Ψ commanded<br />

PI controller<br />

State<br />

Vector<br />

Determination<br />

δΡ,δΠ, δΨ commanded<br />

Aero-dynamics database<br />

(CD, CL, CL, T)<br />

δΡ,δΠ, δΨ meassured<br />

Figure 4-94: Control Law<br />

4.4.5.5 Computation of an optimal 6DoF controlled entry trajectory<br />

Dynamics + NLDI<br />

Crtl generation<br />

HMM<br />

Assessment Study<br />

Report: CDF-20(A)<br />

February 2004<br />

page 352 of 422<br />

The next step in the design is to compute the 6DoF trajectory using mathematical models of<br />

sensors and actuators in the closed loop control simulation tool available at ESTEC.<br />

Commanded by ASTOS<br />

150<br />

Followed by the controller<br />

altitude [km]<br />

velocity [m/s]<br />

100<br />

50<br />

4000<br />

3000<br />

2000<br />

1000<br />

0<br />

0 200 400 600<br />

time [s]<br />

0<br />

0 200 400 600<br />

time [s]<br />

declination [°]<br />

drag acc. [m/s 2 ]<br />

50<br />

40<br />

Figure 4-95: 3DoF and 6 DoF trajectories<br />

30<br />

80 90 100 110 120 130<br />

longitude [°]<br />

15<br />

10<br />

5<br />

0<br />

-5<br />

0 200 400 600<br />

time [s]

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