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jhertzberg
04-18-2011, 10:31 PM
Hello
Robots, just can’t get enough of the darn things.


Overview
starting with a Lynx Scout body, Parallax propeller based servo controller and brain. I would like an 802.11n to serial interface. For prototype work I just use a USB cable.

General Design Concept
What will be taking the field is a early prototype of the Dire Wolf (Daishi). Starting with a repair and resupply mech. A Soviet Mil 24-D hind helicopter was chopped and used to provide power, communication and targeting systems. Finally an old cannon from a KV-1 Russian tank, just to add that certain something.

Walking
Now there is a moving target. I’m learning kinematics (Robot Modeling and Kinematics, Rachid Manseur) and bipedal movement (Bipedal Robots, Christine Chevallereau, Guy Bessonnet, Gabriel Abba, and Yannick Aoustin). The goal was Inverse kinematics based on center of gravity. Now I’m moved that target to inverse kinematics based on center of the moment. That last is only 24 hours old, so it is a little (read that as severely) underdeveloped J

Brains
Parallax Propeller, yep. For those who are not familiar. The Propeller is a eight CPU, shared memory, u-controller. Each CPU or COG can be used to process its own thread. Furthermore a COG can be launched and terminated from another COG. For example the Propeller servo controller uses two cogs to control 16 servos and another cog for communications. The result is they all concurrently run providing communications and servo control reliably. This robot will use two propellers. One to process kinematics and sensors. The other will handle control of at least 15 servos (12 leg, 1 camera, and 2 weapon).

Communication
Currently the top of my list is the RS9110-N-11-22. 802.11n serial device, for about $40. Not far down the list is WiFly GSX Breakout from SparkFun 802.11b/g $85.

http://www.motionmicro.com/products/RS9110%252dN%252d11%252d22.html
http://www.sparkfun.com/products/10050

Camera and Vision
D-link DCS-1130 (802.11n) camera. I’m also keeping an eye out for a 802.11n video to Wifi board so that I can use one of my other small cameras. Current test of the DCS-1130 shows 30fps, 640x480, with nice picture. The board is rather large, but it is a single board. 5V

Turret
Two HS-5645MG will provide horizontal and vertical ability.

Gun
Gun unit from an air soft tank system.

Control System
Saitek X52 joystick (HOSAT), interfaced to a micro ATX with a 17” screen mounted in a Pelican case. Software is RoboRealm.
General flow-joystick->RoboRealm(produces general commands like forward)->Propeller(produce motion path->servo commands)->Propeller servo controller->Servos


Power
Right now I have NiMH 6.0VDC 1500mAh pack. I will upgrade this to Lipo with custom battery boxes (Makerbot). Once I have some current draw measurements. Voltage regulation is a CC Bec Pro 20amp for the servos and a CC Bec 10amp for the computers, video and communication.

Summary
I am ready to start assembling the parts. Once that is done I will start programming. :)
Jeremy

sthmck
04-18-2011, 11:46 PM
Gun
Gun unit from an air soft tank system.

First of all I just wanted to say that I am pretty impressed with the direction you are headed. You have some really good ideas and I am looking forward to seeing what you eventually come up with. I just want to point one thing out to you which may save you a lot of headache later on. After having reffed 70% of the matches at robogames last weekend I noticed that the few people using the tank guns were at a gross disadvantage. Even the more mobile mechs with tank guns had trouble scoring.

Most people assume that the rate of fire is to slow with tank guns, and they are for the most part correct. While the targeting system on registers one hit per second being able to fire 3 to 5 rounds in a second give you a much better chance of scoring a hit. What we are just now starting to realize is that the tank guns are generally just to weak to register on the target panels. At a very close range (1-3) I noticed that a little less than 40% of the shots that hit the target plates actually registered.

I know that getting better guns on a biped is tricky but I would hate to see you put a lot of work into a mech that wont be competitive because of the guns you are using.

lnxfergy
04-18-2011, 11:59 PM
Most people assume that the rate of fire is to slow with tank guns, and they are for the most part correct. While the targeting system on registers one hit per second being able to fire 3 to 5 rounds in a second give you a much better chance of scoring a hit. What we are just now starting to realize is that the tank guns are generally just to weak to register on the target panels. At a very close range (1-3) I noticed that a little less than 40% of the shots that hit the target plates actually registered.

I think the bigger problem is that recent versions of the tank guns are of MUCH lower quality. From the various people I talked to, probably less than 50% of the new "white gear box" guns held up for more than a couple matches worth of rounds.

-Fergs

sthmck
04-19-2011, 12:05 AM
I think the bigger problem is that recent versions of the tank guns are of MUCH lower quality. From the various people I talked to, probably less than 50% of the new "white gear box" guns held up for more than a couple matches worth of rounds.

-Fergs

Good point, I totally meant to mention that too but I am apparently running on a very low battery at this point. This does seem to be the case. I had three or four of the die on me just doing testing in the few weeks before the event.

jhertzberg
04-19-2011, 12:51 AM
Good points, I think I will move my current weapon to stand in till I have the Mech walking.
Thank you very much,
Jeremy

Quantum
04-19-2011, 12:51 AM
The prop is powerful enough to control 24 servos by itself along with a ps2 controller plus sensors. I wouldn't bother with the servo controller's. Just use Beau's servo controller and tweak the code. Take a look at some of my post's here or under Paul K. at parallax's forum.

jhertzberg
04-19-2011, 01:14 AM
Totally the propeller could. I do need to leave room for some latter enhancements since this unit will also be used for other education related projects that will need AtoDs and I2C communications. Moving the servo controllers off of my prop project board freed up an amazing amount of space. In fact it allowed me to move to a small board.

The Propeller Servo Controller was a clean solution and freed up a couple of cogs. The built in level converters are the safest way to go. Finally the PSCi software gave me a quick and dirty check of my servos-center, endpoints, direction, safety position. Always nice to be able to whip out a USB cable and test all your servo systems. Yea it is overkill, but is that not what we are going for :)

Thanks,
Sincerely,

Jeremy

Connor
04-19-2011, 09:58 AM
First of all I just wanted to say that I am pretty impressed with the direction you are headed. You have some really good ideas and I am looking forward to seeing what you eventually come up with. I just want to point one thing out to you which may save you a lot of headache later on. After having reffed 70% of the matches at robogames last weekend I noticed that the few people using the tank guns were at a gross disadvantage. Even the more mobile mechs with tank guns had trouble scoring.

Most people assume that the rate of fire is to slow with tank guns, and they are for the most part correct. While the targeting system on registers one hit per second being able to fire 3 to 5 rounds in a second give you a much better chance of scoring a hit. What we are just now starting to realize is that the tank guns are generally just to weak to register on the target panels. At a very close range (1-3) I noticed that a little less than 40% of the shots that hit the target plates actually registered.

I know that getting better guns on a biped is tricky but I would hate to see you put a lot of work into a mech that wont be competitive because of the guns you are using.

I have a question, I wasn't at RG11 this year.. On the Tank guns, what weight was the BB's the people where using with the tank guns that had issues registering hits on the target plates? I found the tank guns work MUCH better with the .20g weight.. and the higher quality the better. In RG10, I modified my tank guns to run around 4-6 rounds per second.. I have no idea if anyone made this modification in RG11, however.. My guns lasted several matches.. in fact.. the only reason one failed was because I switched to the cheap .17g in the bot brawl at the end. One of those BB's jammed the gun up.. When I got home, that guns motor was failing as well..

Thanks, Connor

lnxfergy
04-19-2011, 10:37 AM
I have a question, I wasn't at RG11 this year.. On the Tank guns, what weight was the BB's the people where using with the tank guns that had issues registering hits on the target plates? I found the tank guns work MUCH better with the .20g weight.. and the higher quality the better. In RG10, I modified my tank guns to run around 4-6 rounds per second.. I have no idea if anyone made this modification in RG11, however.. My guns lasted several matches.. in fact.. the only reason one failed was because I switched to the cheap .17g in the bot brawl at the end. One of those BB's jammed the gun up.. When I got home, that guns motor was failing as well..

Thanks, Connor

Connor, the quality really has gone down from the guns we got the past few years -- and it is very hit or miss. A few people got halfway decent guns, but I think most got piles of garbage. I can't recommend that anyone spend their hard earned money on these things, especially after seeing the kind of firepower they are going to be up against (such as the new guns that Cire/Tyberius were using).

-Fergs

jhertzberg
04-19-2011, 01:41 PM
Replacing the gun issue will be interesting. I think I may take a trip down to the local air-soft/paint-ball and Navy surplus store in Moss Landing, California. I'm thinking they may have the old guts from an updated weapon they could sell.

BB quality at RoboGames 2011 looked like a mixed bag, I was not paying a lot of attention to it but I do remember seeing excellent quality ones all the way to garbage.

BB weight-I think I will dig out my paint-ball velocity measuring device and see if it picks up air-soft rounds. Remember kinetic energy (Ke) kills (lesson from EMT class 20 years ago). Ke=1/2mV^2. Double your weight, double your Ke. Double your velocity and four times your Ke!

Happy hunting :veryhappy:

Jeremy

DresnerRobotics
04-19-2011, 01:57 PM
Just one thing: 802.11N is forbidden.

Sorry, it's spread spectrum and we don't have infrastructure to support it anyway.

jhertzberg
04-19-2011, 06:47 PM
Thanks Tyberius,

I will have to keep my b/g options open then.

Jeremy

DresnerRobotics
04-19-2011, 07:09 PM
Thanks Tyberius,

I will have to keep my b/g options open then.

Jeremy

Most N cameras can run in a B/G mode I believe, we just can't have N protocol taking up the entire 2.4ghz spectrum.

jhertzberg
04-20-2011, 05:33 PM
Mech Cavalry Maintenance and Control (MC MAC)
Mini ATX, 1.6GHz 2G ram, blue tooth, WIFI b/g/n with a 17" screen. Will be adding Video input and external network cable.
Saitek X52 (I give this joystick 5 smilies :happy::happy::happy::happy::happy:, highly recommend)

~Jeremy

http://forums.trossenrobotics.com/gallery/files/5/5/9/2/dscf0053_sml.jpg

cire
04-20-2011, 05:50 PM
Mech Cavalry Maintenance and Control (MC MAC)
Mini ATX, 1.6GHz 2G ram, blue tooth, WIFI b/g/n with a 17" screen. Will be adding Video input and external network cable.
Saitek X52 (I give this joystick 5 smilies :happy::happy::happy::happy::happy:, highly recommend)

~Jeremy

http://forums.trossenrobotics.com/gallery/files/5/5/9/2/dscf0053_sml.jpg


Amazing setup! Did you basically build a desktop into a Pelican case?

jes1510
04-20-2011, 06:59 PM
Replacing the gun issue will be interesting. I think I may take a trip down to the local air-soft/paint-ball and Navy surplus store in Moss Landing, California. I'm thinking they may have the old guts from an updated weapon they could sell.

BB quality at RoboGames 2011 looked like a mixed bag, I was not paying a lot of attention to it but I do remember seeing excellent quality ones all the way to garbage.

BB weight-I think I will dig out my paint-ball velocity measuring device and see if it picks up air-soft rounds. Remember kinetic energy (Ke) kills (lesson from EMT class 20 years ago). Ke=1/2mV^2. Double your weight, double your Ke. Double your velocity and four times your Ke!

Happy hunting :veryhappy:

Jeremy

I was shooting .2g KSC's through my tank guns and I would never even consider recommending the tank guns to someone under any circumstances. They are too slow and the mods required to keep them shooting reliably at a decent speed aren't worth the effort.

You are correct on the energy calculation but keep in mind that to increase your velocity you have to replace a spring in the gear box. Going to a higher weight BB will decrease the velocity but increase the accuracy. The energy within the system will stay the same. I would say to always shoot .2g or better BB's and never shoot anything from Wal-Mart. The roundness alone is a good reason to stay away from those.

jhertzberg
04-20-2011, 07:43 PM
The tank gun is an old one, but I'm going to take your guys advice and dump it.

Sincerely,
Jeremy

jhertzberg
04-20-2011, 07:46 PM
Amazing setup! Did you basically build a desktop into a Pelican case?

Thanks, a MiniATX like one might mount in a car. So very small desktop.

jhertzberg
05-11-2011, 04:03 AM
http://forums.trossenrobotics.com/gallery/files/5/5/9/2/daishi_with_support.jpg
All right, got a spiffy new support structure, new servos for knees arrived (over 400 oz-in).
I have every thing I need to start work on designing a weapon system. Next steps
1) put in new servos
2) load robot and test current draw
3) determine optimal battery packs

Jeremy

jhertzberg
05-16-2011, 01:03 PM
Moving forward a little at a time.
Replaced Daishi's knee servos with HSR-5990TG (about 400 oz-in).
The new servos have a much higher pitch whine.
Increased hight of test support structure.

this week:
2) load robot and test current draw
3) determine optimal battery packs

Jeremy

Stobs
06-12-2011, 12:51 PM
Hi Jeremy, how's the project going? BTW, we're right down the street from each other - possibly literally since I'm in New Monterey currently. :)

[Edit: @Admin: I just posted yet it shows I'm "offline"?! lol]