How the Perseverance rover avoids crashes on Mars
(ORDO NEWS) — The Perseverance rover has many moving parts, including a robotic arm, drill, mast, instrument shrouds, high-gain antenna, and autonomous systems.
Unintentional collision with the rover body or Martian terrain while moving can cause irreparable damage. In addition, the SuperCam instrument uses the LIBS laser on the surface of the planet to create plasma and conduct spectroscopy, and we also want to prevent the laser from hitting any part of the rover.
To avoid this, Perseverance checks for upcoming movements and laser usage with its Rover Collision Model software and autonomously stops any activity before an accident can occur.
To test for a robotic arm collision, Perseverance predicts the next movement of the arm and checks to see if it will collide with the rover body at any time during that movement. If there are no unexpected contacts in the predicted movement, the software allows movement to begin.
Sometimes the arm has to come very close to the equipment or even touch other parts of the rover body, for example, when changing drill bits or collecting samples.
The rover knows when these contacts are intentional and resolves them. When Perseverance autonomously selects scientific targets using the AEGIS tool, it uses the rover’s collision model to filter out any targets that might lead to them before selecting a target to aim for the SuperCam.
Typically, the task force sends commands to the rover once a day, and the Perseverance rover must protect itself if some of these actions go wrong. If the rig encounters even a minor failure, as happened on the 374th day.
The planned use of the LIBS laser the next morning was aimed at the stone, but which was now blocked by the hand. This incident was gracefully averted, as suggested by the rover’s collision model on day 375.
Collision checking occurs autonomously on board, and the task force on Earth usually does nothing. If the motion fails the collision test during the ground simulation and needs to be corrected, the operations team may not even notice it.
The Rover Collision Model was one of the flight software modules we designed and programmed, so we can’t help but think about what it’s doing in the background. As of sol 460, the system has completed over 64,000 collision checks on Mars with no errors, reporting collisions where expected.
We’ve arrived at Hogwallow Flats and look forward to seeing the rover perform many more collision and snag checks while conducting some exciting science exploration.
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