A State Trajectory Planning Method Considering Input Constraint for Variable Pitch Electric Propulsion Units

Variable pitch electric propulsion is one of the most promising propulsion techniques for future aircrafts. In response to a fast dynamic control requirement, a system state trajectory planning method is proposed in this work. The final system state is calculated by the difference equation iteration. The equality constraint is transformed into a tracking error with weight factor. The error and the time consumption form a novel fitness function. The particle swarm optimization method is used to find the optimal time steps of the state trajectory. The theoretical difficulties caused by implicit equations, equality constraints and nonlinear load characteristics are avoided. A state trajectory with less time consumption can be obtained. An improved model predictive trajectory control method is proposed for better servo tracking of the planned reference trajectory. The state trajectory planning results in different conditions are simulated, analyzed and compared. The time-saving effect and better-tracking effect are experimental verified.