 | | Re: Newbie needs Help
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(...) (Or vice-versa!) (19 years ago, 7-Jun-06, to lugnet.robotics)
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| | Re: Newbie needs Help
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(...) Sure, I understand the argument. But this old farm boy has both a few hours in the driver's seat of a farm tractor, as well as a couple of engineering degrees, both of which prompted my cautionary statements. Let me start by saying that I (...) (19 years ago, 7-Jun-06, to lugnet.robotics)
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| | Re: Newbie needs Help
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(...) I don't think Dean was talking about torque from the rope tipping the robot; I think he was talking about the fact that a raised attachment point for the rope can result in a downward component of the tension, increasing the force down on the (...) (19 years ago, 6-Jun-06, to lugnet.robotics)
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| | Re: Newbie needs Help (diff sensor)
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(...) Quite true. My bad. -dave (19 years ago, 6-Jun-06, to lugnet.robotics)
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| | Re: Newbie needs Help (diff sensor)
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(...) I think you need another pair of gears on one of the wheels to reverse its direction. If you are going to use a rotation sensor to measure the slippage then you need to realise that the sensor is notoriously poor at very low speeds. You'll at (...) (19 years ago, 6-Jun-06, to lugnet.robotics)
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(...) What I'm saying is that if the robot is moving along at (say) 3 inches per second - then the drive wheels will get most traction if they are turning at a speed equivelent to 3 inches per second. If they are rotating faster than that (because (...) (19 years ago, 6-Jun-06, to lugnet.robotics)
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| | Re: Newbie needs Help (diff sensor)
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Some varied thoughts here: (...) I might be wrong, but my understanding of the Lego differential gearing is that if both shafts are turning at the same rate and direction, the outer gear/shell will turn at the same rate as the axles. Only when the (...) (19 years ago, 6-Jun-06, to lugnet.robotics)
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| | Re: Newbie needs Help
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(...) Raj, There's a bit of confusion here. I believe the above quote actually came from Steve Baker (posting only as Steve). As Steve Baker pointed out, there is a difference between kinetic (sliding) friction and static friction. ((URL) In the (...) (19 years ago, 6-Jun-06, to lugnet.robotics)
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| | Re: Newbie needs Help
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(...) Ummm.... that's not the way I remember the mechanics. There is a torque created that is force on the drawbar times the drawbar height from ground. That torque will lift your front end. Doubling your own drawbar height halves your pulling (...) (19 years ago, 6-Jun-06, to lugnet.robotics)
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| | Re: Newbie needs Help
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(...) One rotation sensor and a differential will allow you to compare the rotation of two wheels. If the driven wheel and the undriven wheel come in the two sides of the differential, and the rotation sensor is connected to the drive ring, then the (...) (19 years ago, 6-Jun-06, to lugnet.robotics)
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| | Re: Newbie needs Help
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(...) Dean, Thank you for your response. I am going to get on with the tow rope suggestion right away. You might like to know that your 2002 'Building Lego Robots for FLL' guide was the first thing that I read. Raj (19 years ago, 6-Jun-06, to lugnet.robotics)
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| | Re: Newbie needs Help
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You only need one rotation sensor and some fancy gearing. Using a differential in a way similar to the "South Facing Cart" or the stearing drive in a dual differential setup, you could directly measure the amount of spin between a driven wheel and (...) (19 years ago, 6-Jun-06, to lugnet.robotics)
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| | Re: Newbie needs Help
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(...) Steve, One rotation sensor is allowed. There are also two light sensors, so your idea is definitely doable. The situations that are confusing are when the pull of the other robot prevents your robot from making any headway, as well as when (...) (19 years ago, 6-Jun-06, to lugnet.robotics)
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| | Re: Newbie needs Help
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(...) Steve, Provided that my robot doesn't tip-over and that only the front wheels are driven. I have seen a video of a robot in last year's competition that opened up into a V-shape. The angle between the arms of the V being greater than 90 (...) (19 years ago, 6-Jun-06, to lugnet.robotics)
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(...) Steve, Philo's page on 'Wheels, Tyres & Traction' seems to imply that increased speed will not make much of a difference or am I reading that wrong? By 'mechanically connect' do you mean by using two differentials? The maximum 'safe' gearing (...) (19 years ago, 6-Jun-06, to lugnet.robotics)
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| | Mitchel Resnick & NXT were here
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Finally got a chance to have a closeup look at the much talked about Mindstorms NXT when Prof Mitchel Resnick (of MIT Media Lab) was here for the LEGO MINDSTORMS Education (LME) NXT Regional Pre-Launch at the Singapore Science Centre. (URL) (...) (19 years ago, 6-Jun-06, to lugnet.robotics, lugnet.loc.sg)
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| | Re: Newbie needs Help
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(...) Real tanks and dozers have lots of little sprung wheels resting along the bottom edge of the track - adding those would give you back that down-force you miss from the center of the track being unsupported. Tank tracks are a subtle thing in (...) (19 years ago, 5-Jun-06, to lugnet.robotics)
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| | Re: Newbie needs Help
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Steve Hassenplug wrote: > You can (A) add more weight (B) make it go faster, or (C) add more traction. > Considering you're already at the weight limit (out of parts), option (A) is out. > > Making it go faster is a reasonable option. Geared down (...) (19 years ago, 5-Jun-06, to lugnet.robotics)
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| | Re: Newbie needs Help
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(...) Well, I'm not exactly an expert - but it seems to me (if the rules allow it) that attaching the tow rope above the center of gravity of the robot and putting the drive wheels at the end nearest your opponent would result in the force of your (...) (19 years ago, 5-Jun-06, to lugnet.robotics)
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| | RCX and Basic stamp
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can anyone help me. im trying to communicate a basic stamp 2 microcontroller with the RCX 2 via infrared. i dont get the protocol it works on can someone help. -- View this message in context: (URL) from the LEGO Robotics forum at Nabble.com. (19 years ago, 5-Jun-06, to lugnet.robotics)
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