Abstract:

A guidance strategy for elliptical orbital autonomous proximity is proposed based on multiple input sliding mode approach. The coupling nonlinearity and uncertainty in relative dynamic model are overcame by designing a mutiple input sliding mode guidance law. The defined system error expression is modified with adopting the time-togo so that the proximity distance and velocity obtain a better coordinated convergence performance. Then an adptive on-off coefficient is acquired according to the relation between the initial system error and the desired convergence time which is produced using the linear interpolation about the proximity distance error. The control chartering is restrained and the proximity time is increased little with the help of this present adptive on-off coefficient selecting method. Numerical simulation shows that the elliptical orbital autonomous proximity can be achieved accurately with the proposed guidance strategy which is not sensitive to the initial conditions. Especially, the long distance proximity course can be completed rapidly.