Abstract:
A desensitized trajectory optimization method was proposed to improve the precision of small body landing control in complex environment, under the influence of the uncertainty of dynamic parameters and state during small body landing. Firstly, considering the influence of uncertain parameters, the augmented stochastic state equation of small body landing is established, and the uncertainty of the gravitational field of small body and the thrust error of probe engine are regarded as the process noise of landing process. Then, the linear covariance dynamic equation of uncertainty propagating along the nominal trajectory is derived, the covariance matrix of state variables is extended to a new state of the state equation, and the joint performance index weighted by fuel consumption and state covariance is constructed. Then the optimal control problem is solved by direct trajectory optimization method and the trajectory's desensitization is finally improved. Taking 433Eros as an example, the simulation results show that the proposed method can overcome the influence of random parameters in the process of small body landing and improve the landing accuracy.