## Open-loop example systems

The FDC toolbox contains three open-loop example systems, which demonstrate how the Beaver model can be used in practice: OLOOP1, OLOOP2, and OLOOP3. These systems have been included in the FDC directory EXAMPLES; they can be opened by typing `oloop1`, `oloop2`, or `oloop3` at the Matlab command line.

### OLOOP1 and OLOOP2

OLOOP1 and OLOOP2 demonstrate how the system Beaver can be used in practice for non-linear, off-line, open-loop simulations of the 'Beaver' aircraft. OLOOP1 computes responses to control inputs to the elevator, ailerons, rudder, engine RPM, or manifold pressure of the engine, while OLOOP2 computes non-linear aircraft responses to atmospheric turbulence.

Before running a simulation, it is necessary to define the parameters for the aircraft model, by loading them into the workspace using DATLOAD. In addition, it is necessary to load trimmed-flight initial conditions with TRILOAD, or compute trimmed-flight conditions with the ACTRIM utility. These routines can all be started by double-clicking the initialization buttons on top of the OLOOP1 or OLOOP2 models.

### OLOOP3

OLOOP3 demonstrates how to create open-loop simulations of aircraft responses to control inputs using a linearized aircraft model which is derived from the non-linear model Beaver.

The system matrices of the linear state-space model must be defined in the Matlab workspace before it is possible to start a simulation. These matrices can be determined for a user-specified operating point with the linearization routine ACLIN (double-click the appropriate button-block in the block-diagram of OLOOP3 to start this program). They can also be loaded from file (for instance a *.LIN file, created by ACLIN), which can be done conveniently with the utility LINLOAD. Both ACLIN and LINLOAD can be started by double-clicking the initialization buttons on top of the OLOOP3 model.