The composite sinusoidal trajectory control panel allows the pilot
to command the vehicle to rotate the desired attitude about each
individual axis at a rate specified by the sum of two sine waves of
selectable frequencies and magnitudes.
The interface is partitioned into three identical sections, one for each axis. Each section has two identical subsections, one for each of the two sine waves that compose the signal for that axis. The sliders in each of these subsections specify the frequency and magnitude of the two sine waves. When the parameters for the sine waves have been selected for a particular axis, the trajectory about that axis may be commanded to start by pressing the start button for that axis. If the trajectory is stopped and started again, it begins at the current desired attitude about that axis, but with the time variable set to zero for the associated sine waves. These modes are primarily for evaluation of controller performance. These oscillating trajectories are not very useful for typical flight operations.
These sinusoidal commanded trajectories can provide valuable insight into the performance of a particular controller. For example, the quaternion based PD controller will exhibit significant phase lag for a particular trajectory, while the PD plus nonlinear compensation controller takes into account the dynamics of the vehicle, and will significantly reduce phase lag for the same trajectory.