Cynthia Vaskis

SLM521 Spring 2004

Web Quest Assignment

4/21/04

File: wqrover1.htm

Summary of Rover Autonomous Navigation video’s audio

The rover needs to avoid navigational hazards as large rocks and steep slopes while traversing the Martian terrain. The rover uses paired cameras on its head to take stereo vision pictures that it compares to determine how far objects are from the rover. It also uses this data to create a three dimensional patch grid surrounding the rover’s current position and in the direction of the rover’s goal or target location. The rover’s traversing program finds several safe driving pathways to try and selects one based on how close it will get the rover to its target location in the safest and shortest distance.

The rover selects one of these paths and moves a short distance along it looking downward with another pair of cameras on its front underside to avoid going over rocks that could block its wheels or hang up under its underside. When the rover’s traversing program sees obstacles in the pictures and while making the terrain grid database, it creates a model for the obstacles on the terrain grid and expands the size of these obstacles so that the rover does not get close to them when selecting a pathway to travel. After the rover has moved a short distance, the process repeats over taking pictures again and creating a newer terrain grid.

The rover does not move ahead any more if it reaches its goal location or if no safe pathway is found or if Mission Control redirects the rover to stop and do something else. Recently, one of the rovers got stuck with no safe pathway so Mission Control devised a way to have the rover spin around in place by toeing its front and back wheels inward to form a circle pattern. Then the rover could turn in place and try a new directional heading.