Uni Freiburg Rescue Robots: autonomous climbing and visual odometry

Alexander Kleiner from the AI working group at Uni Freiburg has posted some cool videos of their robots on their website. You can see them here. It shows a tarantula robot climbing over various obstacles and using visual odometry to keep track of its position in space. As you cannot use wheel-based odometry on the tarantulas, this is a major step towards self-localization of complex track-based robot in unknown environments.

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Updating my thinkpad…

I tried to update my thinkpad because of this bug. And while doing so, I wondered if the .cab I downloaded actually installed properly. So I chose to updat the AccessIBM software to the newest version to automatically upgrade all drivers. Which told me that the recovery partition on my thinkpad is very outdated. So i downloaded 216 Megs, cleaned up my harddrive to install the installer. Cleaned up my harddrive again to run the second installer that the first installer installed in c:\ibmtools. Defragmented my harddrive to run that installer. Completed the installer. Rebooted as the installer wanted me to do. Ended up with a dead ThinkPad. 🙁

Well, IBM/Lenovo does not really care for a grub installation that you may have on the harddisk. And it also updates the bios on the machine. I don’t really know what side effect this was, but grub only said “GRUB” on boot and nothing more. So I dug out an old Knoppix CD and tried for a couple of hours with grub-install. Didn’t work, no matter what options i gave (–root-directory=/mnt/hda2 –force-lba and whatever) I got “The file stage1 not read correctly.”
This morning, I figured out that grub-install is a shellscript and that this shellscript has some clever safety checks that are sometimes not so clever.

It tries to figure out if the files read by grub are the same as the files read by the OS. If it thinks the files differ, it refuses to install. As I booted from knoppix, it could not figure out the proper mountpoint of /mnt/hda3 (which is my disk root partition) so it thought that the boot/grub/stage1 file on hda3 has somehow not been properly copied. But that file was already there, I just wanted a proper boot sector that the IBM rescue installation wrecked.

So I figured out all I had to do is to start grub manually (as the grub-install does too) to bypass all clever checks and just specify

root (hd0,2)

setup (hd0)

And as grub is smart, it figured out that the files were already present on hd0,2 and installed and configured the boot sector properly. And I rebooted and everything went well since.

Thank you IBM/Lenovo for letting me find out again what I never wanted to know in the first place.

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