PID/First-Order Control Design for a Bank of F-16 Longitudinal Dynamic Systems

This paper presents a guide for designing a set of PID or first-order type attitude controllers for a bank of F-16 longitudinal dynamic models, so that any one of the controller set satisfies the prescribed handling quality requirements. For a scaled down F-16 aircraft, the longitudinal dynamic models between elevator and pitch angle have been identified using the weighted moment matching method with wind tunnel tests, in which ten experiments were performed at three wind velocities, 15 m/s, 20 m/s, and 25 m/s, as the trimmed conditions. The average transfer function models at these trimmed points constitute the model bank M. We here consider the gain and phase margins, the maximum overshoot and settling time limits as the handling quality requirements. In the proposed approach, we first use the results of Bhattacharyya et al. [1] to find the entire set of PI (or first-order) controllers that guarantee the stability margin for a given plant model. Then from this set, we obtain the controller set that satisfies the time response requirements. Repeating this process for three models and taking the intersection of each controller set, we obtain a controller set C that simultaneously meets the prescribed specifications. This set is shown in a 3-D graphic. Simulation shows that an arbitrarily selected controller in this set C meets the design objectives in all three models.