Navigation

While we’re furiously working away to complete the rover construction in time for the challenge, the majority of our other systems are complete.  The next one we’ll talk about is the navigation system.

While this is clearly crucial to completing the mission the on-board vision system is relatively basic.  We are using a stereo-camera to provide a live video stream back to our ground-station/control centre.  This will be our primary vision system and used to navigate the rover, search for the samples and aid the robot arm when collecting them.  In order to make full use of the capabilities this provides we have mounted the camera to a pan and tilt unit.  Coupled with a pair of bright headlights we will be able to use this unit to pan around the crater floor once inside to search for the samples, without wasting additional power driving around the site.

The video below shows the PTU with the camera and headlights attached, in both lit and and unlit conditions.

And here’s our dev-bot with the arm attached on the back and the camera on the front.  These will be next to each other on the final rover however this allowed us to check the camera was capable of giving a clear view of the arm workspace.  It looked great!

 

The devbot rover with arm and PTU/camera/headlights attached.  The combined unit did a great job of illuminating and videoing our lab!

The devbot rover with arm and PTU/camera/headlights attached. The combined unit did a great job of illuminating and videoing our lab!

Also visible in the photo above is the prototype part for the secondary area of our navigation system, the long bar with coloured LEDs at each end.  These lights will be attached at the very front and back of Selene, and will allow us to use our relaybot camera to orientate ourselves back toward our entry point once we have collected the sample.

 

 

The relaybot, with the camera visible mounted on the front

The relaybot, with the camera visible mounted on the front

The principle is fairly simple, while the primary purpose of the relaybot is to allow for wireless communications between the lander site and Selene once inside the crater, the fact that it will have some element of mobility will allow us to position the relaybot on the edge of the crater rim, where we estimate that it’s field of view should cover the entire site we have to explore.  Once we have located and collect the soil sample the relaybot camera will detect the alignment of the red and green LEDs mounted on Selene.  Once directly pointing at the relaybot we will have a clear indicator that we are pointing at our entry point, and therefore the optimal location to exit (in order to achieve maximum points!).  We anticipate becoming easily disorientated and lost after searching the crater floor, this system will allow us to quickly regain our bearings and direct the rover back home to the lander!

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