Choosing a fixed-step Simulink solver (for example, for Real-Time applications)

Most of the time, a fixed-step continuous solver needs to be selected except if there are no continuous states in the Simulink system. Otherwise, fixed-step discrete solvers can be envisaged. Typically, the selection of a fixed-step Simulink solver is necessary for real-time simulations.

To check the solver's accuracy for a small enough step size, you are advised to select ode1 first (n=1), then to proceed via a binary search technique (n+2 then n+1… See the following figure) to choose the best compromise between accuracy and computational effort until ode5. Result accuracy can for instance be verified by comparing with the results obtained with a variable-step solver and/or with those of a reference model that has not been simplified for real-time purpose.

Figure 90: Simulink fixed-step continuous solver selection