“…The lower layer optimization problem of the risk aversion coefficient is characterized by high dimensional order, multistage, non-linearity, and multiple constraints. To solve this type of optimization problem, researchers have proposed improved stochastic fractal search algorithm (ISFSA) (Phan et al, 2021), Coyote Optimization Algorithm (COA) (Heidari et al, 1971) and Discrete Differential Dynamic Planning (DDDP) (Bookstaber and McDonald, 1987;Diniz et al, 2020), etc. Among them, DDDP has the advantage of finding the optimal solution only in the locally feasible domain of state variables, which can effectively reduce the computational storage and computing time compared with other algorithms.…”