Sun Pointing Fine Tuning

The ADCS dynamic system can be divided into two distinct phases:

1. Large-angle maneuvers
2. Small-angle maneuvers/ Steady-state operation

In the second phase, where the system is close to its equilibrium point and the attitude error is near zero, the system can be approximated as linear. Under this assumption, each axis can be treated as decoupled and independent. This allows for the application of linear control techniques commonly used in automated control systems, enabling precise fine-tuning.

Currently, the controller gains in use do not reflect the proportional relationship between the principal moments of inertia. Therefore, we will revisit and adjust the gains to better align with the system's inertia distribution.

Current gains:

• Nadir Pointing :

  • Proportional gain: Kp= [0.0002, 0.0015, 0.0012]
  • Derivative gain: Kd= [0.0075, 0.01, 0.0075]

• Sun Pointing :

  • Proportional gain: Kp_gain = 8e-03 * diag([1, 3, 1])
  • Derivative gain :Kd_gain = 2e-01 * diag([1, 1, 1])

Gains reflecting principal moments of inertia proportions `

• Proportional gains: Kp = [0.311123, 0.312384, 0.0287639]

• Derivative gains: Kd = [0.19246, 0.193275, 0.03727]