In this paper we present recent advances in developing and validating the safeguarded teleoperation approach to time-delayed remote driving. This approach shares control of the rover using a command fusion strategy: In benign situations, users remotely drive the rover; in hazardous situations, a safeguarding system running on-board the rover overwrites user commands to ensure vehicle safety. This strategy satisfies users, because it allows them to drive (except in hazardous situations), while maintaining the integrity of the rover and mission. We present results from experiments on untrained teleoperators with and without safeguarding, which reveal needs to be met by future user interfaces. We describe three technical advances in safeguarding: improving the accuracy of dead reckoning by a factor of 2, speeding up the controller by a factor of 18, and developing an area-based rather than a path-based obstacle avoidance planner in order to circumvent map merging problems. Finally, we dis...

This paper describes practical, effective approaches to stereo perception and dead reckoning, and presents results from systems implemented for a prototype lunar rover operating in natural, outdoor environments. The stereo perception hardware includes a binocular head mounted on a motion-averaging mast. This head provides images to a normalized correlation matcher, that intelligently selects what part of the image to process (saving time), and subsamples the images (again saving time) without subsampling disparities (which would reduce accuracy). The implementation has operated successfully during long-duration field exercises, processing streams of thousands of images. The dead reckoning approach employs encoders, inclinometers, a compass, and a turn-rate sensor to maintain the position and orientation of the rover as it traverses. The approach integrates classical odometry with inertial guidance. The implementation succeeds in the face of significant sensor noise by virtue of senso...

This paper describes a complete stereovision system, which was originally developed for planetary applications, but can be used for other applications such as object modeling. A new effective on-site calibration technique has been developed, which can make use of the information from the surrounding environment as well as the information from the calibration apparatus. A correlation-based stereo algorithm is used, which can produce sufficient dense range maps with an algorithmic structure for fast implementations. A technique based on iterative closest-point matching has been developed for registration of successive depth maps and computation of the displacements between successive positions. A statistical method based on the distance distribution is integrated into this registration technique, which allows us to deal with the important problems such as outliers, occlusion, appearance and disappearance. Finally, the registered maps are expressed in the same coordinate system and are fu...