Simulator motion-drive algorithms - A designer's perspective

Changes in the design of software algorithms for generating physical motion in flight simulators have typically been put forward on the grounds of improved motion cueing. Little attention has been paid to more practical criteria such as computational cost, ease of adjustment, or evaluation by experienced pilots in a realistic simulation environment. A comparison of three of the algorithms most commonly found in the literature has been performed: classical washout, optimal control, and coordinated adaptive. This consisted of pilot evaluations of these algorithms implemented on a six-degree-of-freedom flight simulator simulating a large transport aircraft during low-altitude flight and ground maneuvering. This paper presents the results of that study from the designer's viewpoint. In it, we contend that, with enough effort, most algorithms can be massaged to perform reasonably well, and that a more important consideration is the ease with which a given algorithm can be brought to high performance levels. If this criterion is used, it appears that the classical algorithm is a good starting point, and that the benefits of an adaptive algorithm can be added gradually to obtain the advantages conferred by nonlinear filtering and intelligent cost functions.