John, What sort of duty cycle and frequency do you require for your baseline operations? Some universities have developed some equipment that you may be able to contract out for even less.
Justin S. McFarland -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of [EMAIL PROTECTED] Sent: Tuesday, June 01, 2004 3:00 PM To: [EMAIL PROTECTED] Subject: ERPS-list Digest, Vol 10, Issue 1 Send ERPS-list mailing list submissions to [EMAIL PROTECTED] To subscribe or unsubscribe via the World Wide Web, visit http://lists.erps.org/mailman/listinfo/erps-list or, via email, send a message with subject or body 'help' to [EMAIL PROTECTED] You can reach the person managing the list at [EMAIL PROTECTED] When replying, please edit your Subject line so it is more specific than "Re: Contents of ERPS-list digest..." Today's Topics: 1. Next Meeting ... (Michael Wallis) 2. Re: Re: inertial systems (John Carmack) 3. Re: inertial systems (John Carmack) 4. Armadillo, flight video ([EMAIL PROTECTED]) 5. [Fwd: [AR] ORG member tests regen-cooled N2O+methanol motor] (Sean R. Lynch) ---------------------------------------------------------------------- Message: 1 Date: Mon, 31 May 2004 12:00:01 -0700 (PDT) From: Michael Wallis <[EMAIL PROTECTED]> Subject: [ERPS] Next Meeting ... To: [EMAIL PROTECTED] Message-ID: <[EMAIL PROTECTED]> The next meeting of the Experimental Rocket Propulsion Society will be held this THURSDAY evening at the Bowers Denny's starting at 8:00pm. Items for meeting #283 (03 Jun 2004): - Admin Teams - Documentation - IT - Liaisons - Logistics - PAO - Treasurer - Development Teams - Chief Scientist - Flight Controls - Propellants/Sparger/FF - Regulatory Affairs - Safety - Testing - Project Status - Composites - GizmoCopter/POGO - SmartFlight - Spike The address is: Denny's 3399 Bowers Ave, Santa Clara CA 95054 This Denny's is located a block south of Hwy 101 at Bowers. Bowers is what Great America Parkway becomes south of Hwy 101. Turn LEFT at the first light and RIGHT into the parking lot. Here's a link to a Yahoo Map: http://www.erps.org/map.html Michael ---------------------------------------------------------------------- Michael Wallis KF6SPF (408) 396-9037 [EMAIL PROTECTED] "And I keep praying that this faith we hold in common keeps showing up in the good things we do, and that people recognize Christ in all of it." Philemon 1:6 ------------------------------ Message: 2 Date: Mon, 31 May 2004 14:58:38 -0500 From: John Carmack <[EMAIL PROTECTED]> Subject: Re: [ERPS] Re: inertial systems To: [EMAIL PROTECTED] Message-ID: <[EMAIL PROTECTED]> Content-Type: text/plain; charset="us-ascii"; format=flowed At 08:12 AM 5/31/2004 -0600, you wrote: >John, > > I just got a quote from KVH yesterday for their new 6DOF FOG IMU system -- > > $25,000 and 10-12 weeks delivery. It looks like we will be sticking with > > the Crossbow FOG for a while, although I am keeping my eyes out for either > > a good integrated GPS / IMU that could reduce GPS position jumps, or a set > > of gyros accurate enough to gyrocompass. > >You might want to check with some of the "low-cost ELV" companies. I know >that at least Microcosm and Aeroastro have both developed fairly low-cost >IMU/GPS guidance packages that are supposedly good enough to fly an ELV all >the way to orbit. In at least Microcosm's case, I know that they supposedly >cost less than $30k. That's a heck of a lot for ameteurs, but might be >within These are almost certainly basically what we have -- a FOG based IMU and a separate GPS that outputs position. Our current system should also also be capable of guiding a vehicle to orbit. There is a tighter level of integration that is possible if the core GPS resolving algorithm also has access to inertial data as it weights the values from the various satellites. This can get rid of the occasional discrete steps in position that GPS systems give as they transition from satellite to satellite. A few meters isn't relevant for an orbital vehicle, but it matters for precision landing and maneuvering. Just using differential GPS will probably be a lot easier. John Carmack ------------------------------ Message: 3 Date: Mon, 31 May 2004 15:13:41 -0500 From: John Carmack <[EMAIL PROTECTED]> Subject: Re: [ERPS] inertial systems To: [EMAIL PROTECTED] Message-ID: <[EMAIL PROTECTED]> Content-Type: text/plain; charset="us-ascii"; format=flowed At 11:52 PM 5/30/2004 -0700, you wrote: >On Sun, 2004-05-30 at 12:04, John Carmack wrote: > > Was the code I gave Pierce any help in getting the 3D inertial > > transformations working with your crossbow? For really short flights with > > no significant wobble you might get by with just integrating rates, but > > eventually you will need 3D transformations. > >Yes, although I've gotten a lot more from looking at the functions that >get data from the IMU and do the screen drawing. Your code has been >extremely helpful all the way around. That is from my "quick hacks" directory, so don't read too much into it... >I've never done graphics programming before, so looking at your code and >reading the OpenGL manual pages has got me on the right track for that. >I hope to have the display done tomorrow. The biggest hurdle for starting 3D graphics programming is getting anything at all drawing on the screen. It is really easy to just have the projection or model matrix putting things behind you, or have the triangles drawn backwards so they are culled, or have some critical functionality disable or enabled with the wrong parameters. Modifying sample code that puts something on the screen is a good way to star. > That would allow us to move >Gizmo around and see similar motion on the computer display. Once we're >happy with that I'll add in the PID loops and try controlled flight. > >Matrix math has been the bane of my existence since college, but I think >I'm finally starting to grasp it. Personally, I think much better in terms of groups of vectors than a matrix. My math isn't nearly as advanced as many people think, given my perceived status as a "graphics god". > > I just got a quote from KVH yesterday for their new 6DOF FOG IMU system -- > > $25,000 and 10-12 weeks delivery. > >Ouch. Would this be their "tactical grade" IMU? Yes. >I'm starting to wonder if our IMU will be OK for Gizmo, and I'm sure >that it won't cut it for POGO and later vehicles. We did a couple flights of our very first vehicle frame with tuning fork gyros before moving to FOGs, so you should be able to get some work done with the cheap xbow, which is a good step up from the gyration units we started with. We did have to make a very vibration isolated container for the gyros, with soft foam pads supporting it on all sides, because any good thump would confuse the gyros. The 10hz bandwidth was an issue for us when we were using solenoid based differential engines, but a jet vane vehicle should be able to fly fine with 10hz gyros. I'm still willing to loan ERPS my old KVH gyros if you want. They are discrete single axis analog output FOGs, which aren't nearly as convenient as the integrated IMU, but they do have 100hz bandwidth and are vibration / shock / G insensitive. They were fairly expensive ($1500 each), but they are now a discontinued product. You could have them on loan if someone is willing to take responsibility for $2000. John Carmack ------------------------------ Message: 4 Date: Mon, 31 May 2004 20:26:06 EDT From: [EMAIL PROTECTED] Subject: [ERPS] Armadillo, flight video To: [EMAIL PROTECTED] Message-ID: <[EMAIL PROTECTED]> Content-Type: text/plain; charset="US-ASCII" http://www.armadilloaerospace.com/n.x/Armadillo/Home/News?news_id=260 Nice job! In a few weeks, the Armadillo flight test vehicle went from 4 motors with differential thrust steering to one large motor with exhaust vane steering! And they flew some hops to prove it works. That's progress. John C. told us at Space Access '04 that it doesn't look like Armadillo will be ready for a shot at the X-Prize before it terminates, but with the rapid development they've shown, I've started hoping ... cheers from Allen Meece in S. Florida members.aol.com/beanstalkr/project/ ------------------------------ Message: 5 Date: Tue, 01 Jun 2004 08:52:37 -0700 From: "Sean R. Lynch" <[EMAIL PROTECTED]> Subject: [ERPS] [Fwd: [AR] ORG member tests regen-cooled N2O+methanol motor] To: [EMAIL PROTECTED] Message-ID: <[EMAIL PROTECTED]> Content-Type: text/plain; charset="us-ascii" Skipped content of type multipart/mixed-------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 256 bytes Desc: OpenPGP digital signature Url : /archives/erps-list/attachments/20040601/66634507/signature.pgp ------------------------------ _______________________________________________ ERPS-list mailing list [EMAIL PROTECTED] http://lists.erps.org/mailman/listinfo/erps-list End of ERPS-list Digest, Vol 10, Issue 1 **************************************** _______________________________________________ ERPS-list mailing list [EMAIL PROTECTED] http://lists.erps.org/mailman/listinfo/erps-list
