Reduction of time delays in Runge-Kutta integration methods

Numerical (digital) integration in a real-time simulation is often performed using explicit Runge-Kutta methods. Real-time system simulation places high demands on computers and integration routines, if data must be sampled from input signals and incor porated into the numerical integration algorithm in order to evaluate the derivatives of the state variables. A modified fourth-order Runge-Kutta (RK4) method, which meets these requirements particularly well is proposed. As an example the routine is applied to a complex flight simulation problem. The results of the modified routine and of the RK4 standard are compared and the specific advantages of the new routine demonstrated.