Closed loop control for autonomous approach and placement of science instruments by planetary rovers

The underlying motive of "follow the water" in the search for evidence of past or present life on Mars has led NASA to deploy increasingly sophisticated robotic missions to the planetary surface. Opportunity and Spirit, the current pair of MER (Mars Exploration Rovers) on Mars for over a year, have both discovered evidence of past surface water. Optimal use of mission resources, such as ground planning time and surface operation duration, for increased science data return becomes critical with each advancement in the capabilities of the onboard instrument suites. This paper presents a novel, end-to-end, fully integrated system being developed at JPL (Jet Propulsion Laboratory) that is called SCAIP (Single Command Approach and Instrument Placement). SCAIP enables a rover to autonomously travel to a designated science target from an extended distance away, and precisely place an instrument on that target with a single command without additional human interaction. The results of some experimental studies with a rover in terrestrial settings and using imagery returned from MER are also described.

I. Introduction

Since 1997, JPL has successfully landed three rovers on the surface of Mars, including the Sojourner rover in 1997 and the two MER, Spirit and Opportunity in 2003. The Sojourner rover had a two-degrees of freedom instrument deployment device (IDD) for the alpha proton X-ray spectrometer. MER has a five-degrees of freedom IDD, with a suite of four instruments at the end-effector, including a microscopic imager (MI), a rock abrasion tool, a Mössbauer spectrometer, and an alpha proton X-ray spectrometer. The MI is a fixed focus camera with a touch-rod for surface contact sensing. An advanced technology prototype of the MER called the FIDO (Field Integrated Design and Operations) rover is shown in Fig. 1, with the IDD in contact with a rock during a recent field trial. FIDO was used for algorithm development and training of MER science personnel for ground operations [1], [2], [3].