Re: [CAD_CAM_EDM_DRO] Re: Re: Re: Hexapod question

>alex wrote:
>
>
>
>>Why not to make legs of hexapod of hydraulic cylinders with feedback
>>encoders?
>>Position can be locked in place with the valve.
>>
>>
>>
>>
>No, not really. If you have a valve that locks the cylinder, then there
>is a delay
>and a jerk when the lock is released. The standard system is to use
>Moog-type
>proportional hydraulic servo valves, which are VERY expensive. These valves
>need to have dither added to the command signals to keep the spools from
>sticking. You need 12 flexible hydraulic lines, 6 $5000 servo valves, 6
>high-resolution linear encoders, and a huge hydraulic pump, in the 5 to 10
>Hp range. Yes, you can do this, and it will work, but it is "old school",
>fantastically expensive, high maintenance, VERY noisy, dangerous to
>work on (a ruptured hydraulic line, or even a pinhole leak can be fatal!)
>and gobbles up a huge amount of electrical power, even when sitting
>still.
>
>Jon
>
>
>Addresses:
>FAQ: http://www.ktmarketing.com/faq.html
>FILES: http://groups.yahoo.com/group/CAD_CAM_EDM_DRO/files/
>Post Messages: CAD_CAM_EDM_DRO@yahoogroups.com
>
>Subscribe: CAD_CAM_EDM_DRO-subscribe@yahoogroups.com
>Unsubscribe: CAD_CAM_EDM_DRO-unsubscribe@yahoogroups.com
>List owner: CAD_CAM_EDM_DRO-owner@yahoogroups.com, wanliker@..., timg@...
>Moderator: pentam@... indigo_red@... [Moderators]
>URL to this group: http://groups.yahoo.com/group/CAD_CAM_EDM_DRO
>
>OFF Topic POSTS: General Machining
>If you wish to post on unlimited OT subjects goto: aol://5863:126/rec.crafts.metalworking or go thru Google.com to reach it if you have trouble.
>http://www.metalworking.com/news_servers.html
>
>http://groups.yahoo.com/group/jobshophomeshop I consider this to be a sister site to the CCED group, as many of the same members are there, for OT subjects, that are not allowed on the CCED list.
>
>NOTICE: ALL POSTINGS TO THIS GROUP BECOME PUBLIC DOMAIN BY POSTING THEM. DON'T POST IF YOU CAN NOT ACCEPT THIS.....NO EXCEPTIONS........
>bill
>List Mom
>List Owner
>
>
>
>Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>
>
>
>