FULL SCALE FLIGHT DEMONSTRATION OF LIDAR-BASED HAZARD DETECTION AND AVOIDANCE

摘要

International space agencies want to maximise the scientific return of planetary exploration missions with the minimum level of risk. This goal can be achieved by implementing the capability of landing spacecrafts with high precision and safety nearby known surface targets of interest such as craters, boulders and hills. Innovative guidance, navigation and control technologies are needed to achieve that goal. It requires the capability to identify boulders and slopes on the surface of the celestial body and react rapidly in order to guide the spacecraft toward a safe region. This capability is known in the literature as Hazard Detection and Avoidance (HDA). In previous papers presented at various conferences, the design of a Lidar-based autonomous planetary landing system and its validation using software simulators and scaled hardware-in-the-loop simulators were presented. This paper is a continuation of this work and presents the demonstration at full scale of this technology using helicopter flight test experiments, with Lidar measurements processing and HDA software functions operated in real time using a flight representative Lidar instrument. The first flight test experiments of this program were performed with success during the month of October 2010 and additional flight test campaigns were conducted during September 2011 using an upgraded and consolidated version of the design. This paper begins with a description of the latest design version of the Lidar-based autonomous planetary landing system. Then, the paper presents the methodology adopted to validate the interfaces and the performance of the landing system in a scaled and repeatable environment using a robotic test bench, the so-called Landing Dynamic Test Facility (LDTF). This laboratory environment enables the efficient, low-cost and low-risk validation of the complex landing system before proceeding to the more expensive and more risky flight experiments. The paper then presents the flight test validation methodology using a helicopter on a steep descent (Mars-like) and shallow descent (Moon-like) trajectory toward terrains with representative slopes, rocks and boulders. The paper concludes with the presentation of the flight experiment results and a detailed analysis of the achieved performance.