forum.TeamFREDNET.org

by **Joerg** » Mon 2008 Oct 20 10:45 pm

I added the WRV1 page to the WIKI

see: http://wiki.xprize.frednet.org/index.php/Portal:WRV1

Saluti Joerg

by **tobiokanobi** » Tue 2008 Oct 21 5:12 am

Great design!!!!

-tobi

by **Joerg** » Thu 2008 Nov 06 11:29 pm

The gearbox has been created!

Have a look: http://wiki.xprize.frednet.org/index.php/Portal:WRV1

JÃ¶rg

by **alexc** » Mon 2008 Nov 10 2:18 pm

Yeah, cool design

I have just added the pictures to our official team blog http://www.googlelunarxprize.org/lunar/ ... n-for-wrv1
Next in the loop is Tobi's Jaluro.

by **alexc** » Fri 2008 Dec 05 4:16 pm

JÃ¶rg has posted new pictures on the wiki today, showing wheel parts he manufactured. Check it out on the WRV1 portal. Great work JÃ¶rg!

by **air.command** » Fri 2008 Dec 05 6:25 pm

Very nice work Joerg!

by **Joerg** » Tue 2008 Dec 16 8:51 am

The wheel is born!

Have a look on it here:
http://wiki.xprize.frednet.org/index.php/Portal:WRV1

Saluti JÃ¶rg

by **ryanw** » Tue 2008 Dec 16 11:54 am

that is really cool, cant wait to see it in action.

by **alexc** » Tue 2008 Dec 16 11:59 am

Yeah, thumbs up! It really looks like on the drawing; something I never managed to accomplish with mechanical stuff :lol:

by **AndersFeder** » Tue 2008 Dec 16 12:09 pm

Nice job. The structural design bears some resemblance to the wheels on the Lunakhod rover, which I think is a good sign.

by **alexc** » Tue 2008 Dec 16 12:13 pm

I was wondering... You write the weight will come down to 60g/wheel. How much total weight will they be able to support?

by **Joerg** » Wed 2008 Dec 17 12:27 am

Thank for the "flowers"!

As Tobias asked me if this design will save weight i may explain the advantages of it:

I started with the idea to have as much area as possible in contact with the regolith, so a flexible belt like a almost flat tire would be the solution. Since i do not like "plastics" to be use in harsh environments, the idea to use somewhat like a track came up. With Stokys i did a simple test because in this system they made once a chain with plastic segments, so i was convinced it could work. Doing some 3D drawings i saw the the side effect was a light weight construction. So thats how and why.

JÃ¶rg

by **Joerg** » Wed 2008 Dec 17 5:03 am

I have forgotten to answer alexc's question:
Until now, i did not measure the spring rate of my construction, but the rovers weight of 2000 grams is no problem, and on the surface of the moon it will be 1/6th.

When the measurements are don I will inform about the results.

JÃ¶rg

by **alexc** » Wed 2008 Dec 17 5:28 am

Ok, thanks. I was just curious about the weight ratio between the supporting components and the total weight since I don't know much about mechanics. Of course, I understand it also depends on the materials and such.

by **Joerg** » Wed 2008 Dec 17 6:35 am

Hi alex
I did not much of calculating. I think it is the best way to try (in this case!) calculating the springs and friction is rather a nightmare and i do not have time nor do i like this kind of calculating (even if it may be interesting).

JÃ¶rg

by **AndersFeder** » Wed 2008 Dec 17 6:58 am

Joerg wrote:I did not much of calculating. I think it is the best way to try (in this case!) calculating the springs and friction is rather a nightmare and i do not have time nor do i like this kind of calculating (even if it may be interesting)

Could you open a task with the necessary information in the wiki, perhaps, in case someone else is up for the challenge?

by **Joerg** » Thu 2009 Jan 15 1:31 pm

If anybody is willing to produce hardware instead of bytes!!

In the WIKI is now a section with BULEPRINTS (even if they are B&W) so you can go on working.

The WRV1 WIKI:
http://wiki.xprize.frednet.org/index.php/Portal:WRV1

and here the drawings:
http://wiki.xprize.frednet.org/index.ph ... Blueprints

Good luck

JÃ¶rg

by **alexc** » Fri 2009 Jan 16 1:15 pm

Cool stuff, JÃ¶rg. It also keeps our blog busy

by **ryanw** » Fri 2009 Jan 16 3:11 pm

Hey Joerg,
what are you using to do the 3D CADs? looks like Solidworks?
-Ryan

by **Joerg** » Sat 2009 Jan 17 4:22 am

No it is a low cost version called "Becker CAD" (http://www.databecker.de/beckercad_5_pro.html) which is a older version from Caddy. I actually use the version 2 pro, but the actual version is 5. The costs are about $100 the "pro" version about $200.

The CAD is easy to handle, so it would be nice if also other members of the team would use it.

JÃ¶rg

by **Joerg** » Tue 2009 Jan 27 5:08 am

See now the new wheel hubs twinkling!

http://wiki.xprize.frednet.org/index.php/Portal:WRV1

JÃ¶rg

by **alexc** » Tue 2009 Jan 27 6:49 am

Very impressive!

by **air.command** » Tue 2009 Jan 27 2:02 pm

Joerg wrote:See now the new wheel hubs twinkling!

http://wiki.xprize.frednet.org/index.php/Portal:WRV1

JÃ¶rg

Very nice work JÃ¶rg!!

by **tristancho** » Tue 2009 Jan 27 5:48 pm

They are so nice!
Joshua

by **Joerg** » Tue 2009 Jan 27 11:01 pm

Thanks and the weight IS the expected 25 grams, as my CAD calculated!

JÃ¶rg

PS: I have added an overview of WRV1 in the WIKI!

by **Joerg** » Fri 2009 Jan 30 4:28 am

Some more pictures are added to the WIKI (including WRV1 on the moon surface!).

http://wiki.xprize.frednet.org/index.php/Portal:WRV1

JÃ¶rg

by **tobiokanobi** » Sat 2009 Feb 07 4:22 pm

Hi JÃ¶rg,

Thanks again for the wheel CAD drawings.

Another topic:

Some of us would like to start to develop a webapplication working as user input interface to control an rover (and to recieve feedback from the rover) - the software shall be designed to work "independend" of the Rover design (using rover dependend librarys/interfaces).
If you have an idea on what parameters you would like to use,set,...please write me a short email!

Thank you very much,

Tobi

by **Joerg** » Mon 2009 Feb 09 11:20 pm

Some more drawings:

http://wiki.xprize.frednet.org/index.php/WRV1-Blueprints

JÃ¶rg

PS: They are in production rigth now!!

by **tristancho** » Tue 2009 Feb 10 2:45 pm

I like drawings!
Nice,
Joshua

by **alexc** » Wed 2009 Feb 18 8:23 am

Somebody raised a question on our team blog whether thermal expansion in the extremes of temperature is going to be a problem for the wheel spokes? Any comment on that?

by **Joerg** » Wed 2009 Feb 18 9:10 am

The design of the wheel and the spokes is not critical for thermal expansion. Also the choise of material was made having extreme temperatures in mind.

JÃ¶rg

by **tristancho** » Wed 2009 Feb 18 11:31 am

I like this wheel spoke design.

Young modulus (Spring coefficient) may change with temperature (let say from -200 ÂºC to +200 ÂºC) but I suppose WRV1 don't run in the lunar night so is not a problem. As per RoverSim could be easy modeled changing this spring coefficient depending on temperature.

If WRV1 life cycle was for years, hysteresis could be a problem for springs but this is not the life cycle for WRV1.

Regards,
Joshua

by **alexc** » Wed 2009 Feb 18 1:27 pm

A new WRV1 video showing the assembly of the steering unit is now available:
http://www.youtube.com/watch?v=MHy9sr8GsaQ

Even simple things can provide great footage for a video, so keep those video footages coming to me!

by **tristancho** » Wed 2009 Feb 18 4:23 pm

Great!
Joshua

by **Joerg** » Thu 2009 Feb 19 9:48 am

And there are some more pictures in the WIKI:

http://wiki.xprize.frednet.org/index.php/Portal:WRV1#2009-02-19

JÃ¶rg

by **ross_brigoli** » Wed 2009 Feb 25 8:08 pm

Hi Joeg,

Very impressive machining job! Have you decided yet how to drive this rover? I mean, how much power/torque needed to turn the wheels and to steer half of the frame? Considering the gear ratio you initially have put up on the design...

This is very promising.

- Ross

by **Joerg** » Thu 2009 Feb 26 8:19 am

Dear Ross

Yes, I did some calculations first.

The torque of the motor itself is in the range of 1 mNm, this will produce a force of about 0.3 Nm at the motor gear unit and some more torque on the wheels.

The steering unit's stepper motors have about 10 mNm torque (each) and the gearbox will multiply this torque about 100 times.

The efficiency of the gears are about 50%. Since the rover is rather a snail (2 m per minute) the power consumption is very low. The WRV1 test rover has two 1W motors and drives four times faster than the real WRV1.

JÃ¶rg

by **ryanw** » Thu 2009 Feb 26 3:57 pm

so most power on rover will go towards comm>?

by **Joerg** » Fri 2009 Feb 27 11:37 am

Yes, especially for HD-Video.

Shortly some more info about the steering unit!

JÃ¶rg

by **Joerg** » Mon 2009 Mar 02 1:46 pm

Ther is the new mockup of WRV1!

http://wiki.xprize.frednet.org/index.php/Portal:WRV1#2009-03-02

JÃ¶rg

by **alexc** » Mon 2009 Mar 02 2:05 pm

Wow, just how cool is that?! A combination of state of the art wheels and Stokys... That's just perfect!

by **tristancho** » Mon 2009 Mar 02 3:35 pm

Impresive!
Joshua

by **ryanw** » Mon 2009 Mar 02 4:26 pm

That is really cool Joerg!

by **scasey** » Mon 2009 Mar 02 7:12 pm

Yes - I agree - very nice to see hardware. Are there plans for a video showing actual operations?

by **ross_brigoli** » Mon 2009 Mar 02 11:02 pm

The overall design is very impressive. I'm just curious about the drive wheels. Is this front drive, rear drive or does each wheel has individual drive motor? My concern is how do we steer the rover? I noticed two motors on the center joint in the photo. Or, are those encoders? I also noticed a little deformation of the wheels... Is this normal?

Fantastic job Joerg!

by **Joerg** » Mon 2009 Mar 02 11:23 pm

Here some answers:

- I will do some videos as soon as the vehicle is moving

- steering is done by the center part. There are two stepper motors for that purpose. Because of the redundant concept each one (shuld) is capable to "bend" the rover.

- yes the wheels shall be deformed, so they will act as suspension and have a bigger contact surface

- the four motors are actually missing. Look at the drawings for the details how they will look like.

Saluti JÃ¶rg

by **Joerg** » Sun 2009 Mar 29 8:16 am

I have uploaded some more pictures in the WIKI!

http://wiki.xprize.frednet.org/index.php/Portal:WRV1#2009-03-28

The steering unit is now moving the two WRV1 modules. I am preparing a PDF-document showing all the drawings, schematics and PCBs as well as other infos like calculations. If anyone is interested I will send it via eMail -> just ask!

As soon WRV1 is moving (RC controlled for the moment) i will do a video!

JÃ¶rg

by **scasey** » Sun 2009 Mar 29 10:29 am

Will it be possible to operate this rover remotely using the 'Rover Director' (RD) software? How would this be accomplished?

SC

by **ARAGORN II** » Sun 2009 Mar 29 10:30 am

Only now I've seen this thread, congratulation Joerg! It's really a great work, and it's also very interesting.

Is there a tread or a wiki page where I can read something about the WR1 movment?

Thanks.

by **Joerg** » Mon 2009 Mar 30 12:07 am

to scasey

If i will control the WRV1 rover depends on various factors! Since the WRV1 design is based on "Do it as simple as possible, but not simpler!, I will decide that later.

to ARAGON II
have also a look here:

the WIKI
http://wiki.xprize.frednet.org/index.php/Portal:WRV1

the blueprints
http://wiki.xprize.frednet.org/index.php/WRV1-Blueprints

the previous tread
http://forum.xprize.frednet.com/viewtopic.php?t=204

JÃ¶rg

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