 | | High Strength Powered Steerable pivot wheel
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I am building a shrimp-style rover along the lines of what Mario Ferrari built. I uses 6 powered wheels. A pair on each side in lateral boggies, One in the front on an articulated arm, a rear fixed to the chassis. Problem is coming up with a strong (...) (24 years ago, 21-May-01, to lugnet.robotics)
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| | Re: High Strength Powered Steerable pivot wheel
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(...) Do you need to steer each wheel independently? The only really strong turntable element you can also pass a drive through is the Technic Turntable (2855/2856 on Partsref) but you would need six. The internal teeth would make it easy to drive (...) (24 years ago, 21-May-01, to lugnet.robotics)
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| | Re: High Strength Powered Steerable pivot wheel
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I was unfamiliar with that turntable. I will have to see if I can find some. Anybody know of an esay to find kit that include them? I only need two: Front and rear. The steering is handle mainly by the front and rear with the side wheels driven like (...) (24 years ago, 21-May-01, to lugnet.robotics)
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| | Re: High Strength Powered Steerable pivot wheel
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I'm sorry to hear that, because my design was going to use a single axle. My plan is for an eight wheel drive, four wheel steering shrimp. Last night I successfully prototyped a pneumatic steering system. It doesn't solve your problem, though. It (...) (24 years ago, 21-May-01, to lugnet.robotics)
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| | Re: High Strength Powered Steerable pivot wheel
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(...) I don't think there are any current sets which include it. But... You will have noticed all the traffic about the 'classic' re-releases coming this autumn. 8459 (to be renumbered 8464) Front End Loader has one though 270DM might be a bit (...) (24 years ago, 21-May-01, to lugnet.robotics)
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| | Re: High Strength Powered Steerable pivot wheel
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(...) coming (...) There's no turntable in this set, the middle steering joint is a 40T gear. And the green 8446 crane truck has a black turntable amongst it 573 elements (according to lugnet set reference) Simon PS: What's that about those (...) (24 years ago, 21-May-01, to lugnet.robotics)
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| | Re: High Strength Powered Steerable pivot wheel
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(...) I think that no current set includes them. But it's available as spare part in the Pitsco/DACTAcatalog (US only). (...) This is actually the same solution I was thinking to implement: steerable front and rear wheels and side wheels driven like (...) (24 years ago, 21-May-01, to lugnet.robotics)
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| | Re: High Strength Powered Steerable pivot wheel
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The problem appears to be leverage. I have no exposed shaft at all. But the force while climbing stairs still managed to snap the axle at the pivot point. I was suprised the axle broke and the retainers did not just pop off. A steerable shrimp is a (...) (24 years ago, 21-May-01, to lugnet.robotics)
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| | SHRIMP building was: Re: High Strength Powered Steerable pivot wheel
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(...) In the near term, I've opted out of the "steer in place" requirement. That way I go from four outputs to two. With an 8-wheel SHRIMP, I steer like a four-wheel steered (FWS) car does at low speed. Also, I don't have to worry about the friction (...) (24 years ago, 21-May-01, to lugnet.robotics)
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| | Re: High Strength Powered Steerable pivot wheel
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(...) Well I feel a total fool, sorry Steven. (Embarrassment tempered by the fact that you can still get them.) (...) Here's the original post about this... (URL) (must remember to switch brain on while at work in future) (24 years ago, 21-May-01, to lugnet.robotics)
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| | Re: SHRIMP building was: Re: High Strength Powered Steerable pivot wheel
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(...) way I (...) four-wheel (...) 8-wheel (...) You drive all the wheels together in the same direction (first output), and use a motor to steer the front and rear groups in sync (second output). Is this what you mean? Very clever. You cannot steer (...) (24 years ago, 22-May-01, to lugnet.robotics)
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| | Re: SHRIMP building was: Re: High Strength Powered Steerable pivot wheel
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(...) Yes, something like this: | is a wheel pointed straight, \ and / are wheel turned left or right = is the body Going straight: | | |==| |==| | | Turning left: \ \ |==| |==| /==/ Turning right: / / |==| |==| \ \ Disclaimer: I haven't actually (...) (24 years ago, 23-May-01, to lugnet.robotics)
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| | Re: SHRIMP building
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(...) Yes, something like this: | is a wheel pointed straight, \ and / are wheel turned left or right = is the body Going straight: | | |==| |==| | | Turning left: \ \ |==| |==| / / Turning right: / / |==| |==| \ \ Disclaimer: I haven't actually (...) (24 years ago, 23-May-01, to lugnet.robotics)
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| | Re: High Strength Powered Steerable pivot wheel
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(...) All the replies were apparently trying to help you to create a steerable wheel with no motors in the assembly. Did you consider rotating the entire motor/wheel assembly? The advantage is that you don't need a drive to go through the rotating (...) (24 years ago, 23-May-01, to lugnet.robotics)
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| | Re: High Strength Powered Steerable pivot wheel
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(...) I'm looking forward to the old sets, my last taste of LEGO was in the 70's, and all my bricks from that time are long gone. Mindstorms have re-kindled my love of lego, and technics feed the machine. If the two technics sets are re-released, it (...) (24 years ago, 23-May-01, to lugnet.robotics)
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| | Re: High Strength Powered Steerable pivot wheel
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IN my design the motor and wheel assembly are one unit. The problem has been keeping the rotation point stong enough. Hopefully I can play around with some things this weekend. I will probably order the large turntables from pitsco. They should (...) (24 years ago, 23-May-01, to lugnet.robotics)
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