Authors: Arturo Rankin, Mark Maimone, Jeffrey Biesiadecki, Nikunj Patel, Dan Levine, Olivier Toupet
Year: 2020
- Review of MSL mission (exploring Gale crater and Mount Sharp)
- Curiosity = 6 wheels rover, that can rotate in both direction independantly (except middle wheels that are not steerable)
- Visual odometry enables SLIP estimates: evaluate the slip fraction by comparing the motion of VO with the one of wheel odometers
- Excessive SLIP may raise a fault or even stop the sol
- 99,55% of VO convergence
Categories of VO failure:
- Failed to converge (mostly due to a lack of features)
- Bug in step truncation (FSW is supposed to truncate large step to prevent from VO failure)
- Sequencing failure: Rover planners may send commands outside of the normal bounds
- Strategy filure
- IMU parameter failure
Drives Modes:
- the whole VO process takes 47s on average
- Autonomous mode alternates between full VO (ie one iteration every meter) and slip checks (every 20 meters)
- Visual target tracking ie visual servoing. Tracking is performed with a correlation function cf Overview of the Mars Exploration Rovers’ Autonomous Mobility and Vision Capabilities (already available on MER)
- Path planning with D* algorithm
- Details of all drive failure cause (slip limits, time of the day exceeded, obstacle, tilt limit)
- TRCTL adapt each wheel speed to fit the topography: enables longevity of wheels and actuators
Belle histoire, considération intéressante sur la mission et les causes d'échec. Mais HS pour la thèse