On-line robust trajectory generation on approach and landing for reusable launch vehicles

Extension of motion primitives and neighboring optimal control used in trajectory generation for RLVs

“…On-line A&L trajectory generation using MP and NOC was introduced in [2] and discussed thoroughly in [3], [4]. This section will give a brief review of the approach discussed in [3] and [4].…”

“…The gliding flight in a vertical plane of symmetry is then defined by the following point mass equations ([2]- [4], [9])…”

“…In this paper, the main concern is to extend these approaches to the trajectory generation for RLVs during TAEM and A&L when the system dynamics considers lateral ground track. Note that all failures considered in this paper and [2]- [4] correspond to the case of a stuck effector.…”

“…Second generation (and future generation) RLVs may eventually take the place of the space shuttles, but not before scientists perfect the technologies that make RLVs safer, more reliable, and less expensive than the shuttle fleet. At each of four major flight phases -ascent, re-entry, terminal area energy management (TAEM), and approach and landing (A&L), a variety of new RLV trajectory design approaches have recently been proposed [1]- [4]. Since A&L is a critical flight phase that brings the unpowered vehicle from the end of the TAEM phase to runway touchdown, the authors imposed the most efforts on the development of new approaches that could deliver an RLV to its landing site safely and reliably, recover the vehicle from some failures, and avoid mission abort as much as possible.…”

Controllable set analysis for planetary landing under model uncertainties

“…For this reason, several researches on model uncertainty have been conducted in Titan entry (Kazeminejad et al, 2011), Mars entry (Li and Peng, 2011), Earth reentry (Jiang and Ordó ñ ez, 2009), etc. In order to deal with the large perturbation on approach and landing for reusable launch vehicles, trajectory robustness theorem is applied to the trajectory generation in the reentry to Earth (Jiang and Ordó ñ ez, 2009). To improve Mars entry precision, desensitized optimal control is adopted by minimizing the sensitivity of trajectory to entry state perturbation (Li and Peng, 2011).…”