Missile Acceleration Controller Design using PI and Time-Delay Adaptive Feedback Linearization Methodology
For missile autopilot designers, this work offers a practical solution to acceleration control with nonminimum phase and uncertainty, though it is an incremental improvement over existing feedback linearization methods.
The paper addresses missile acceleration control under nonminimum phase dynamics and model uncertainties by proposing a cascade controller combining approximate feedback linearization with a time-delay adaptation scheme and an outer PI loop. Numerical simulations and 6DOF tests demonstrate effective tracking and compensation for model errors.
A straight forward application of feedback linearization to the missile autopilot design for acceleration control may be limited due to the nonminimum characteristics and the model uncertainties. As a remedy, this paper presents a cascade structure of an acceleration controller based on approximate feedback linearization methodology with a time-delay adaptation scheme. The inner loop controller is constructed by applying feedback linearization to the approximate system which is a minimum phase system and provides the desired acceleration signal caused by the angle-of-attack. This controller is augmented by the time-delay adaptive law and the outer loop PI (proportional-integral) controller in order to adaptively compensate for feedback linearization error because of model uncertainty and in order to track the desired acceleration signal. The performance of the proposed method is examined through numerical simulations. Moreover, the proposed controller is tested by using an intercept scenario in 6DOF nonlinear simulations.