Optimal soft landing control for moon lander

• Published in: Automatica (Oxford) Vol. 44; no. 4; pp. 1097 - 1103
• Main Authors: Liu, Xing-Long, Duan, Guang-Ren, Teo, Kok-Lay
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.04.2008; Elsevier
• Subjects: Applied sciences; Computer science; control theory; systems; Constraints transcription technique; Control parameterization technique; Control system synthesis; Control theory. Systems; Exact sciences and technology; Lunar lander; Optimal control; Optimal soft landing; Time scaling transform; Lunar lander; Time scaling transform; Constraints transcription technique; Optimal soft landing; Optimal control; Control parameterization technique; Control synthesis; Fuel consumption; Parameterization; Constrained optimization; Control constraint; Inequality constraint; State constraint
• ISSN: 0005-1098; 1873-2836
• DOI: 10.1016/j.automatica.2007.08.021

This paper considers the soft landing problem of a moon lander. The main purpose is to design the optimal control law to ensure the soft landing of the lander with the least fuel consumption. It is formulated as a constrained optimal control problem, where specific requirements of this soft landing problem are all incorporated in the problem formulation. Then, by utilizing the specific features of the problem, this optimal soft landing problem is transformed into an equivalent standard optimal control problem subject to continuous state inequality constraints. A computational method is developed, based on the control parameterization in conjunction with a time scaling transform and the constraint transcription method, to design the optimal controller for this new constrained optimal control problem. Numerical results are presented for illustration.