Motion simulation capabilities of three-degree-of-freedom flight simulators

This paper presents the results of a study aimed at determining the simulation realism that might be achieved using reduced-degree-of-freedom flight simulator motion bases, More specifically, the quality of motion produced by two different three-degree-of-freedom platforms was compared to that produced by a conventional six-degree-of-freedom Stewart platform, The three-degree-of-freedom motion bases investigated were a spherical mechanism allowing only rotational motions, as well as a motion base capable of heave, pitch, and roll motions, To compare the different motion bases, three characteristic maneuvers were simulated using a nonlinear model of a Boeing 747, The aircraft motions were then simulated on nine different combinations of virtual motion platforms and motion base drive algorithms, The motion cues (specific forces and angular velocities) produced in this manner were then graphically compared, The analysis revealed that, in most cases, a three-degree-of-freedom simulator is capable of producing motion simulation quality comparable to that produced by a six-degree-of-freedom Stewart platform, Analysis of the motion sensations, as produced by a vestibular model, revealed nearly the same results as the motion analysis.