  Fixed-wing Miniature Air Vehicle (MAV) is not only coupled with longitudinal
motion, but also more susceptible to wind disturbance due to its lighter
weight, which brings more challenges to its altitude and airspeed controller
design. Therefore, in this paper, an improved longitudinal control strategy
based on energy state, is proposed to address the above-mentioned issues. The
control strategy utilizes the Linear Extended State Observer (LESO) to observe
the energy states and the disturbance of the MAV, and then designs a
Multiple-Input Multiple-Output (MIMO) controller based on a more coordinated
Total Energy Control (TEC) strategy to control the airspeed and altitude of the
MAV. The performance of this control strategy has been successfully verified in
a Model-in-the-Loop (MIL) simulation with Simulink, and a comparative test with
the classical TEC algorithm is carried out.
