Search found 67 matches

by rghansen
04 Nov 2010, 18:37
Forum: Mindstorms Hardware
Topic: NXT servo motor robustness
Replies: 14
Views: 8685

Re: NXT servo motor robustness

Thanks for the additional confirmation. But I started to have my doubts when I read that Lego was offering replacement linear actuators to some of their unhappy customers. (You also mentioned this problem in your bided topic). I was thinking about buying a set of these. How can I be sure that I'll g...
by rghansen
02 Nov 2010, 18:57
Forum: Mindstorms Hardware
Topic: NXT servo motor robustness
Replies: 14
Views: 8685

Re: NXT servo motor robustness

Thanks for the info. You've taken the worry out of pushing them a little harder.
by rghansen
02 Nov 2010, 18:27
Forum: Mindstorms Hardware
Topic: NXT servo motor robustness
Replies: 14
Views: 8685

NXT servo motor robustness

What's the consensus on the robustness of NXT servo motors?

Will they overheat if we run them at full power for extended periods?

Will their gears fall apart if we drive them much harder than we would ever drive our cars?

Will a little gentleness go a long way to extending their useful existence?
by rghansen
24 Oct 2010, 20:09
Forum: Robot Building
Topic: My nxt cant turn well help!
Replies: 4
Views: 3630

Re: My nxt cant turn well help!

Can you post an image of your robot? A non-caster robot needs a rear differential or some other means of letting the two rear wheels turn at different rates. Without this, they don't corner very well. A quick fix is to only drive one rear wheel.
by rghansen
17 Oct 2010, 19:52
Forum: Mindstorms Projects
Topic: a Kalman filter to fuse gyro and compass readings
Replies: 79
Views: 41747

Re: a Kalman filter to fuse gyro and compass readings

physics-matt wrote:
Sounds like you are talking about SLAM (simultaneous location and mapping). It's well worth reading up on (wikipedia is a good place to start) and if you can get it working on the NXT then you'll get a lot of kudos!

Matt
Thanks for the SLAM tip.
by rghansen
17 Oct 2010, 19:44
Forum: Mindstorms Projects
Topic: a Kalman filter to fuse gyro and compass readings
Replies: 79
Views: 41747

Re: a Kalman filter to fuse gyro and compass readings

What I would like to know is exactly why the compass has such a strong dependence on its tilt (i.e. how far it is off being horizontal). Having a better understanding of the underlying physics of it may help to find better ways to compensate. Even better, do we know whether anyone else has made a c...
by rghansen
17 Oct 2010, 19:33
Forum: Mindstorms Projects
Topic: Stonehenge 3: A fast, precise robot arm
Replies: 29
Views: 20233

Re: Stonehenge 3: A fast, precise robot arm

As you probably noticed, I also modified the cable guide. The Flexi-cables from mindsensors.com needed a bit more support than the orginal Lego cables.
stonehenge_cable_guide.jpg
stonehenge_cable_guide.jpg (87.96 KiB) Viewed 7782 times
by rghansen
17 Oct 2010, 19:29
Forum: Mindstorms Projects
Topic: Stonehenge 3: A fast, precise robot arm
Replies: 29
Views: 20233

Re: Stonehenge 3: A fast, precise robot arm

Thanks for the photos. I think you may also have altered the bottom end of the ball chute where it meets the first stand. Can you give any detail of alterations here? For example, it looks like you've used two 13 beams instead of the 13 plus 11 one specified in Philo's original design. I can't quit...
by rghansen
17 Oct 2010, 14:13
Forum: Mindstorms Projects
Topic: Stonehenge 3: A fast, precise robot arm
Replies: 29
Views: 20233

Re: Stonehenge 3: A fast, precise robot arm

I'm including just one more photo to show that if given enough time, I can actually get one of these fully automatic digital cameras to focus on what I want. It is a closeup of the light shield. The 3 black beams sit on top of beams that are suspended from the two stands on either side of the color ...
by rghansen
17 Oct 2010, 13:59
Forum: Mindstorms Projects
Topic: Stonehenge 3: A fast, precise robot arm
Replies: 29
Views: 20233

Re: Stonehenge 3: A fast, precise robot arm

I think I've found the problem. I had the grab and lift arm motors the wrong way round. I think your program is different to the nxt-g allocation. Also I notice that the port for the light sensor is also altered. Now I've corrected the wiring it is beginning to work. Some adjustments necessary, as ...