To address the performance limitations caused by the independent design of internal and external ballistics in traditional field artillery rockets

this study proposes an integrated internal-external ballistic collaborative optimization method for range maximization aimed at enhancing overall performance. A coupled integrated ballistic computational model is established by developing a joint solution framework that combines a zero-dimensional internal ballistic model of solid rocket motors with six-degree-of-freedom external ballistic motion equations

enabling real-time interaction of coupling parameters including thrust

mass

center-of-gravity

moment of inertia

and ambient back pressure. External ballistic optimization is performed under design parameters

followed by the implementation of multi-objective collaborative optimization for engine parameters and flight trajectories using the Non-Dominated Sorting Genetic Algorithm II (NSGA-II) under optimized external ballistic schemes. A modular computational program is developed to support dynamic parameter feedback and multidisciplinary coupling iterations. Taking a tail-fin controlled field artillery rocket as the research object

the optimization focuses on maximizing range through adjustments in propellant web thickness

burning surface area

nozzle expansion ratio for both boost and sustainer stages

along with angle-of-attack control schemes. Results demonstrate that the coupled optimization achieves 15.5% range extension

1.95% increase in velocity at burnout

6.33% enhancement in maximum altitude

and significant improvement in thrust profile-flight trajectory coordination. The research validates the effectiveness of the integrated ballistic model and NSGA-II algorithm in resolving dynamic coupling problems

providing a novel methodology for energy utilization optimization and system design of field artillery rockets.