Mars Perseverance Sol 87-Left navigation camera: The first docking on Mars, in Sol 87 [May 18, 2021]. The image was captured by Perserverance's left navigation camera shortly after the arm was docked. Bit Carousel is a conical object in the center of the image. Image source: NASA/JPL-Caltech
Docking occurred twice during the sample collection period. First, the robotic arm stops to put down the grinding bit currently clamped, and picks up the coring bit with the empty sample tube. Then, after collecting the rock sample, it stops again, and puts down the coring bit with the now filled sample tube. The sample tube will be processed, sealed and stored by the buffer assembly.
Mars Perseverance Sol 21 – WATSON camera: An overview of the pier in front of Perseverance, taken by the WATSON camera on the robotic arm. When this image was acquired, the door in front of the drill conveyor was still closed and has since been opened. Image source: NASA/JPL-Caltech
The working principle of the docking is to guide a group of small columns at the end of the robotic arm to a group of matching cones on the dock. Imagine plugging the charger into a mobile phone or computer-even if you don’t think about it, you rely heavily on the tactile feedback from your hand and fingertips to feel whether you need to slide the plug to the side to align it a bit and know when Reach the bottom. The docking works in the same way. The force sensor at the end of the robotic arm tells Perseverance the force and direction it is pushing. Perseverance uses this data to guide the robotic arm into position and determine when to complete the docking. (The base also includes microswitches at the bottom of each cone. Press these microswitches when the arm is almost docked, as an additional verification). Once the post reaches the bottom of the cone, the robotic arm pushes into the dock harder with nearly 650N (146 lbs) of force to ensure it remains docked during the bit exchange.
In JPL's 6-year career, I have spent most of my time in docking work. My goal is to make it reliable and simple-just like plugging in a mobile phone. Achieving this requires a lot of design and testing (including nearly 2,000 alignments on various test platforms on Earth), and it is an honor to be able to successfully see the docking on Mars many times. I was a little nervous every time we collected samples, but I crossed my fingers for more successful and easy docking attempts.
Written by Sawyer Brooks, NASA/JPL docking system engineer.
The email address is optional. If provided, your email will not be published or shared.
SciTechDaily: The best home of science and technology news since 1998. Keep up to date with the latest technology news via email or social media.
The research results can provide information for the design of new materials, such as iridescent windows or waterproof textiles. If you touch the wings of a butterfly,...
Copyright © 1998-2021 SciTechDaily. all rights reserved.