Algorithmic improvements for simulator motion drive

Contemporary simulator motion drive algorithms typically are designed in an analog (continuous) environment, but are implemented in a digital (discrete) environment. The intended continuous system, specified as frequency domain (Laplace transform) transfer functions, may not be represented properly by the algorithms used for digital implementation. The motion drive software in use with the Vertical Motion Simulator at Ames Research Center was investigated recently; the original algorithms (Euler) were changed to a state transition method. Comparison of the frequency responses of the original and new implementations showed that the state transition method more closely approximates the desired analog responses. In addition, test pilots who evaluated both implementations preferred the motions generated with the state transition method over those generated with the Euler integration method.