Trajectory optimization method for air-to-air missiles with trim tab deflection constraints

Abstract This paper investigates the impact of incorporating trim deflection constraints in missile trajectory optimization, aiming to address the inaccuracies that may arise from neglecting such constraints in traditional methods. Based on the dynamics and aerodynamic models of the AM120D air-to-air missile, a trajectory optimization problem that includes trim deflection constraints is formulated and solved using the Radau pseudospectral method. The results indicate that incorporating trim deflection constraints leads to significant changes in flight time, maximum altitude, and maximum range, with noticeable differences in the trends of angle of attack, Mach number, and flight path angle during flight. The variation in key parameters ranges from a minimum of 12.7% to a maximum of 26.9%, highlighting substantial discrepancies between trajectories with and without trim deflection constraints. Further analysis reveals that the influence of different initial center of mass positions on the trajectory is relatively small, while the impact of trim deflection constraints on the optimization results is significant. This underscores the critical importance of incorporating trim deflection constraints in trajectory optimization research, as it ensures that the results are more realistic and valuable for engineering applications.