A demonstration hybrid computer for real-time flight simulation

Abstract

A hybrid, real-time simulation facility has been de signed, constructed, and demonstrated, using as a test vehicle the complete aerodynamic and engine equations for a high-performance military aircraft. The analog-digital configuration employs peripheral analog equipment to represent a linear, skeleton version of the aircraft and the PDP-1 digital com puter to carry out engine simulation, decision man agement, and corrections for nonlinear effects. To provide an all-digital reference against which the hybrid simulation could be compared, the air craft model was also simulated in real-time on the PDP-1 alone. It was found that the solution rate of 20 per second employed in the all-digital study could be reduced substantially without deleterious effects when the hybrid configuration was used. Such a re duction demonstrates that supplementing a digital computer by relatively inexpensive analog peripheral equipment greatly increases the real-time capacity of the digital computer in complex simulation appli cations. Moreover, because a number of key variables are computed continuously in the analog domain, the introduction of analog equipment results in a net decrease in the complexity of the interface.