 | | Re: How to get non-circular movements?
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(...) Greetings, An "elliposgraph" aka "elliptic trammel" should be just what you need. (URL) (20 years ago, 23-Aug-04, to lugnet.technic)
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| | Re: How to get non-circular movements?
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(...) Have an arm attached off-center on a gear, running through a fixed pivot point (that is free to rotate!). As the main gear rotates, the distance between the driven end of the arm and the pivot point changes as the off-center attatchment point (...) (20 years ago, 23-Aug-04, to lugnet.technic)
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| | Re: why won't my biped walk?
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(...) Congratulations! Always happy to help out a biped fan. I love them. Make sure you take a picture and post it here, so you can be added to the "Walker Madness" list. (...) For me, building is about experimenting and exploring. Each of my MOC's (...) (20 years ago, 23-Aug-04, to lugnet.technic)
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| | How to get non-circular movements?
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Short question: how can I combine technic gears, arms, cams, etc. to make a motor-driven part that does not move in either a straight line, a circle, or an arc (i.e. part of a circle)? Long question: I'm trying to figure out how to drive an arm so (...) (20 years ago, 23-Aug-04, to lugnet.technic)
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| | Re: New MOC: large crane
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(...) Hi ROSCO, The slew ring uses a roller bearing based on the what-you-ma-call-it-...big-wheels wheels. For some strange reason it did not occur to me to use one wheel and then have a flat surface on the bottom of the upper works, so the ring is (...) (20 years ago, 23-Aug-04, to lugnet.technic)
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| | pneumatic help
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Kevin- I am in the design phase of my crane (the Demag AC 500-1 SSL) and currently I am working on the control system for the pneumatics. Following Ross Crawford's idea, I came out with something like this: (URL) am trying to control four pneumatic (...) (20 years ago, 22-Aug-04, to lugnet.technic)
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| | Re: New MOC: large crane
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(...) finished! I like the use of technic turntables for the crawler sprockets. Did you also use a technic turntable for the slew ring? ROSCO (20 years ago, 23-Aug-04, to lugnet.technic)
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| | New MOC: large crane
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Hi, After working on it for one year (on and off), I've finished a large, crawler crane. Read all about it here (scroll past my minifig crane to the bottom of the page): (URL) (20 years ago, 23-Aug-04, to lugnet.technic) !!
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| | Re: why won't my biped walk?
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(...) Just a follow-up -- all I had to do was slightly redesign and reattach the feet, with the cam-driven connection on the outside and the stabilizing connections on the inside. It now walks quite reliably! Very cool. This bot is cute in a sort of (...) (20 years ago, 23-Aug-04, to lugnet.technic)
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| | Re: why won't my biped walk?
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(...) I think you're right. For the record, I tried simply shifting the foot plates in one stud each -- and this does sort of work; the bot now wobbles a lot but, most of the time, actually transfers from foot to foot. But I think your analysis (...) (20 years ago, 23-Aug-04, to lugnet.technic)
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| | Re: why won't my biped walk?
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(...) OK, so I think I know why it won't walk. Right now, the rotation axis of the ankle is on the outer edge of the foot. This means that when the center post lifts the foot, the inside edge of the foot lifts, while the outside edge of the foot (...) (20 years ago, 22-Aug-04, to lugnet.technic)
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| | Re: why won't my biped walk?
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(...) Oh, I was under no illusions that this would magically solve your problem, and it should be possible to compensate enough for an inconsistent COG that it won't matter in the long run. It's the transition point between the two where it'll (...) (20 years ago, 22-Aug-04, to lugnet.technic)
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| | Re: why won't my biped walk?
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"Joe Strout" <joe@strout.net> wrote in message news:I2us3r.9oF@lugnet.com... (...) walker, (...) doesn't (...) Take a look at another "Joe" He is my favorite for making simple things do complex work. (URL) (20 years ago, 22-Aug-04, to lugnet.technic)
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| | Re: why won't my biped walk?
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(...) I'll try that. Though if it works, I may still be baffled as to why. What is it that causes the CG to move over the down foot at all? At the start of a walk cycle (when we go from both feet flat to one foot lifting), you have one foot lifting (...) (20 years ago, 22-Aug-04, to lugnet.technic)
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| | Re: why won't my biped walk?
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(...) I appreciate the attempt, but I don't think that's it. Despite how it might look it is, in fact, very carefully balanced, and the bot doesn't seem to favor one foot over the other. Thanks, - Joe (20 years ago, 22-Aug-04, to lugnet.technic)
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| | Re: why won't my biped walk?
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(...) Good explanations so far. Here are some additions. The problem is that you are not truly getting the center of gravity inside the footprint of the down foot. The critical part is to get the center of gravity past the inside edge of each foot. (...) (20 years ago, 22-Aug-04, to lugnet.technic)
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| | Re: why won't my biped walk?
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Here's my opinion: Your CG is too low or your feet are tooo heavy. Your bot is not able able to put enaugh weight over to one side (or the other) to balance on one leg. Try either making lighter feet or raise your CG by raising the motor assembly up (...) (20 years ago, 22-Aug-04, to lugnet.technic)
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| | Re: why won't my biped walk?
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(...) A useful first step would be to clean up the construction of the motor/gear housing to make it symmetrical. With how jumbled some of those parts look, I'd be very surprised if your center-of-gravity isn't off-center. If it is, that would mean (...) (20 years ago, 22-Aug-04, to lugnet.technic)
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| | why won't my biped walk?
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A newbie needs some help here... I tried to make a biped COG-shifting walker, based on the many excellent examples found in the archives here. But it doesn't walk -- it just tips up onto the edges of its feet. Here's the starting position (both feet (...) (20 years ago, 22-Aug-04, to lugnet.technic)
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| | Re: SSClagorpion - Let the fun resume
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(...) I was in a rush getting ready for BrickFest. I changed over my radial compressor from yellow to red (SSClagorpion's official color). In the process I accidentally cut the hoses on four pumps. I've changed the outer bracing structure so that (...) (20 years ago, 21-Aug-04, to lugnet.technic)
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