Search found 76 matches

by physics-matt
19 Oct 2010, 07:08
Forum: Mindstorms Projects
Topic: Lasers, Diffraction Gratings, NXT
Replies: 7
Views: 6628

Re: Lasers, Diffraction Gratings, NXT

Oh well. Still a nice project - thanks for sharing!

Matt
by physics-matt
18 Oct 2010, 23:32
Forum: Mindstorms Projects
Topic: Lasers, Diffraction Gratings, NXT
Replies: 7
Views: 6628

Re: Lasers, Diffraction Gratings, NXT

Very cool indeed!

Could you give us some measurements of how far the gratings were from the projected images and how far apart the rings were? It would be fun to see whether we can calculate the diffraction grating separation! (I appreciate that's some strange meaning of the word "fun" ;) ).

Matt
by physics-matt
18 Oct 2010, 23:18
Forum: Mindstorms Projects
Topic: Proposal how to proof the navigation correction by sensors
Replies: 16
Views: 11427

Re: Proposal how to proof the navigation correction by sensors

Just a couple of observations: you may read the compass sensor values and you may change motor speeds of each motor due to the compass results in order to move straight ahead and/or to turn at each vertex. Are we allowed to use any other sensors for this test of the compass? My concern is that the c...
by physics-matt
17 Oct 2010, 21:12
Forum: Mindstorms Projects
Topic: a Kalman filter to fuse gyro and compass readings
Replies: 79
Views: 48786

Re: a Kalman filter to fuse gyro and compass readings

It's not that easy as you think it would be. I never said it was easy! I'm just trying to point you to work that I know about that may help you along the way to solving your problem, even though it doesn't solve your whole problem. If you would rather I don't try to help in this way in future pleas...
by physics-matt
17 Oct 2010, 19:30
Forum: Mindstorms Projects
Topic: a Kalman filter to fuse gyro and compass readings
Replies: 79
Views: 48786

Re: a Kalman filter to fuse gyro and compass readings

I'm sure - no: I am convinced that your method does not achieve the required accuracy to me (estimated 0,1-0,2% navigation accuracy for a maze mapper and solver, size about 10m x 7m for all rooms on the floor, driving around about 1 hour at a go). Well, it was never designed to. If you want to achi...
by physics-matt
17 Oct 2010, 15:49
Forum: Mindstorms Projects
Topic: a Kalman filter to fuse gyro and compass readings
Replies: 79
Views: 48786

Re: a Kalman filter to fuse gyro and compass readings

I just used the Wait function and chose a length of time such that, at the power it was running, I got roughy 1m. Obviously, the exact distance will depend on battery power levels etc, but during the course of a single run it will move the same distance each time, which is the most important thing. ...
by physics-matt
17 Oct 2010, 15:09
Forum: Mindstorms Projects
Topic: a Kalman filter to fuse gyro and compass readings
Replies: 79
Views: 48786

Re: a Kalman filter to fuse gyro and compass readings

Ok, so I've just programmed my robot to go round a 1m^2 square and finish reliably in the same spot & orientation as it started (to within a couple of cm and degrees). Each turn was conducted by moving the motors until the compass sensor measured the desired bearing. No odometry was used at any poin...
by physics-matt
16 Oct 2010, 23:01
Forum: Mindstorms Projects
Topic: a Kalman filter to fuse gyro and compass readings
Replies: 79
Views: 48786

Re: a Kalman filter to fuse gyro and compass readings

doc-helmut, I've just been looking through your code and it appears that you check the compass or odometry measurement each time the robot stops (please correct me if I'm wrong - not being able to read German and only having a small amount of experience with RobotC makes it difficult to understand y...
by physics-matt
16 Oct 2010, 22:15
Forum: Mindstorms Projects
Topic: a Kalman filter to fuse gyro and compass readings
Replies: 79
Views: 48786

Re: a Kalman filter to fuse gyro and compass readings

this is the Ultimate Question - why do we want to improve navigation data if we don't want to improve the results of navigation? [OT] Wasn't the ultimate question "what do you get if you multiply six by nine?" ?[/OT] But seriously, there is a good reason why this is not the question we should be tr...
by physics-matt
16 Oct 2010, 22:01
Forum: Mindstorms Projects
Topic: a Kalman filter to fuse gyro and compass readings
Replies: 79
Views: 48786

Re: a Kalman filter to fuse gyro and compass readings

These results would tend to suggest that my basic platform may be a little more accurate than the one used by Matt That's not at all surprising as I made no attempt to make my platform return to its original bearing. The point that (nearly) everyone here has realised is it's the comparison between ...