Abstract: The trajectory optimization of ascending stage for multi-stage solid launch vehicle using artificial fish-swarm optimization algorithm is presented. The flight program angle of ascending stage is designed. A pseudo-spectral method is used to discretize the dynamic optimization problem into the parameter optimization problem. The fish-swarm algorithm is used to solve an initial ballistics as the initial value, and the parameter optimization problem is solved by SQP. The simulation results show that the fish-swarm algorithm can effectively solve the trajectory optimization problem of multi-stage solid launch vehicles. The flight duration of the optimized scheme is reduced. The algorithm has a fast convergence rate, requires less control parameters, and has a low dependence on the initial value. It is easy to implement and has a good reference for studying the ballistic optimization of multi-stage solid launch vehicles.

Key words: trajectory optimization, artificial fish-swarm optimization algorithm, multi-stage solid launch vehicle, pseudo-spectral method, Matlab simulation