Attitude Control System

The SOLIS Attitude Control System page enables you to select one of two Attitude Control System Model Levels, as well as to configure the three main SOLIS controllers (if you select PIID Control).

Selecting the Attitude Control System model level

There are two levels of modeling for the attitude controller:

  • Perfect Control
  • PIID Control

Control Options

Perfect Control

When you select Perfect Control, the ODySSy simulated spacecraft attitude and rate for each body axis are set equal to the corresponding attitude and rate commands generated by the spacecraft flight software. The result is attitude and rate errors that are always zero. You do not need to define actuators, and there is no commanding of any defined actuators under Perfect Control.

Rate damp has unique behavior when you select Perfect Control. The simulated spacecraft attitude is set to the estimated attitude at the time of the mode command and the simulated spacecraft rate is set to zero. Perfect Control will produce inconsistent simulation attitude state results for a nonzero rate damping mode target rate; i.e., it will show a static quaternion with a nonzero spacecraft rate. If you need nonzero rate damping mode target rates, use PID control instead.

PIID Control

Selecting PIID Control opens up three tab where you can customize the PID control loops for attitude control and momentum control. See the individual controller pages for more information.