Planetary cliff descent using cooperative robots

Erik Mumm, Shane Farritor, Paolo Pirjanian, Chris Leger, Paul Schenker

Research output: Contribution to journalArticlepeer-review

22 Scopus citations


Future robotic planetary exploration will need to traverse geographically diverse and challenging terrain. Cliffs, ravines, and fissures are of great scientific interest because they may contain important data regarding past water flow and past life. Highly sloped terrain is difficult and often impossible to safely navigate using a single robot. This paper describes a control system for a team of three robots that access cliff walls at inclines up to 70°. Two robot assistants, or anchors, lower a third robot, called the rappeller, down the cliff using tethers. The anchors use actively controlled winches to first assist the rappeller in navigation about the cliff face and then retreat to safe ground. This paper describes the coordination of these three robots so they function as a team to explore the cliff face. Stability requirements for safe operation are identified and a behavior-based control scheme is presented. Behaviors are defined for the system and command fusion methods are described. Controller stability and sensitivity are examined. System performance is evaluated with simulation, a laboratory system, and testing in field environments.

Original languageEnglish (US)
Pages (from-to)259-272
Number of pages14
JournalAutonomous Robots
Issue number3
StatePublished - May 2004


  • Behavior
  • Cliff decent
  • Cooperating robots
  • Planetary exploration
  • Robots for planetary exploration
  • Tethers

ASJC Scopus subject areas

  • Artificial Intelligence

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