چكيده لاتين :
In th is paper a closed-loop time-optimal con trol strategy for the non-lin ear lusuu: letuler mission is developed, Generally, determination of closed-loop feedback control law is not usually feasible for many
non-linear dynamic systems, In
addition, there exist certain difficulties associated with the numerical
determination of open-loop optimal control solution for non-lin ear
systems , such as slow convergence rate and high sensitivity to initial guesst imates, Besides, if one manages to overcome th eseinherent
difficulties, the determined optimal control strategy will be in an open -loop form, and thus, fully dependent on the initial condition , Obviously, in this way perturbations and noise processes unll ma ke the optimal
trajectory deviate from its ideal predicted values in any actual operating enuironmeni. Our study focuses on th e planar traj ectory and
control optimization of a lunar lander spacecraf t as a viable example of nonlin ear dynamic system, A fuzzy algorithm is augmented to our
variational formulation of the problem in an attempt to create a closed-loop fuzzy guidance logic, The training process of the fuzzy system is greatly reduced throuqb. the in troduction of a set of states related non-dimensional variables, Simulation
results indicate that the developed meth odology can be successfully ut ilized in other flight scenarios with good robustness to the actuator and measurment system noise.
