In a motion system, the high-frequent portion (or onset part) of a linear motion cue is
generated by linear acceleration of the motion platform in the direction of the specific force
vector. Washout schemes are used to keep the platform within the physical confines of the
motion system hardware. Washout means returning the simulator platform back to the
neutral position following the generation of the onset part of a motion cue.
The low frequent portion (or sustained part) of the linear motion cue is generated by tilting
the motion platform and allowing the gravity vector to provide the cue, or gravity alignment.
Care should be taken that the angular acceleration in pitch or roll direction used in
performing gravity alignment stay below perceptible level.
For rotational motion cues only the onset part is generated in the corresponding motion
system degree of freedom. Washout filters are used to slowly return the system to the neutral
position.