Quote:
Originally Posted by Qbranch
Rockin Sweet! How does the suspension system operate? Is it six wheel drive, or how many wheels drive? Does it four wheel steer, or how does it steer? What type of computer are you using? Are you building your own drive electronics, or are you using premade ones? *johnny 5 voice* Need Input! INput! 
Anyhow, on the lidar part, unfortunately there's not a whole lot you can do about getting a cheap lidar unit. Many universities are in the market for them, so there's not a whole lot of reason for them to give you an educational discout. However, there are people I know who have managed to get a scratch-and-dent lidar unit from Sick at about 75% off. (which, brings you down to a not-much-more-manageable sum of $5,000  )
What type of environment are you trying to nav in? Perhaps you can avoid using a lidar unit? Let us know! Mechanically it looks like a pretty cool machine. 
-q |
The suspension, unfortunately, works on two axes. The end wheels are free to pivot as you can see, and the drive for those is internal. A shaft runs inside the pivoting hub. Once inside, timing pulleys transfer power to the wheels. The center wheel drive was one of the difficult parts of designing this robot. Due to the resources available, we couldn't duplicate NASA's proven Pathfinder, Spirit, and Opportunity rocker-boggie system, so we had to find another solution. The center wheel can't move in any way that would interfere with the end wheels, so I came up with a four bar linkage suspension. This is slightly more complicated and expensive, so we're only using it on the center wheels. The drive is also internal, using universal joints that align with the linkage joints. We plan on using budget mountain bike shock absorbers.
The steering is traditional skid steering. The idea is to have the springs on the end wheels under less compression to give the same effect as elevating the end wheels by a small amount.
As for electronics, I'm probably not the right one to ask for details. We're using an embedded Linux board about the size of a hand. I believe it has a 200 MHz processor, but it could be more. It has 3 RS-232 ports that we're using for GPS, slave (the FRC controller), and Radio. It also has an ethernet port which we are connecting to a wireless router for wifi programming (we're using the python language, which doesn't need a compiler, so basically, you connect to the router on the rover, drag the updated program into the FTP, and it runs). We have two USB ports for whatever we want, as well as an awesome lime green backlit LCD for diagnostics. We're using a Garmin receiver for GPS, which is meant for this kind of use. As for speed controllers, we are using Victors on the drive, but if we get around to an arm, we have a surplus of small stepper motors. The radio will work up to 1 mile. I've figured out a modular payload system, so we'll be able to try various sensor arrays and cargo containers.
As for LiDAR, we found a unit for only $2600 (heh, only). Unfortunately, that's still more than we're willing to dish out on one thing. The electronics are already running up the bill. The rover is meant for all terrain though, so LiDAR may be vital, especially if we want to do dynamic navigation. The rover has substantial ground clearance, and can traverse shallow waters, and if I find a way, slightly less shallow waters. I could say a lot more, but I'd be here for a long time. There's been tons of revision.
You can see some of the design process, electronics, and fabrication at
http://flickr.com/photos/bear24rw