Multi-objective adaptive sliding manifold control for More Electric Aircraft

The increased usage of electric and electronic devices on board the aircraft requested by the "More Electric Aircraft" (MEA) requires the adoption of multi-objective control algorithms, with controllers (supervisors) able to autonomously switch among different objectives. However, the operating point changes during operations, and "small signal" analysis becomes inconclusive to assess overall stability. Thus, the use of standard Proportional-Integral (PI) or Proportional-Integral-Derivative (PID) controllers may become an issue. In this paper, by using nonlinear mathematical tools, the theoretic stability of the controlled electrical devices is considered. Two different control tasks are considered, namely battery charging and generator current limiting. Then an automaton supervisor switches between the two control objectives. Each objective is achieved by using a sliding mode control with adaptive sliding manifold. The adaptation strategy increases robustness, and is crucial for MEA applications, since the controlled system parameters are highly uncertain, due to their harsh environment. Rigorous stability proofs are given, along with detailed simulations in different scenarios. Also hardware implementation is proposed and a comparison with existing strategies (i.e., the Proportional-Integral) is presented, showing the effectiveness of the proposed approach.