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Robot Challenge !!

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  • LarryLarry Posts: 212
    edited 2007-03-26 23:48
    20 mph = 105600 ft/hr

    105600 ft/hr /60 = 1760 ft/min

    10" x pi = 31.416 in/ rev

    1760 ft / 31.416 in == 672.2689 rpm


    pretty fast motor for those little wheels.

    Larry

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  • Brian_BBrian_B Posts: 818
    edited 2007-03-27 00:05
    Thank's Larry ,
    I have some 2300 rpm motors , I beleive that should put me in the roughly at 5mph . That should be just fine to start out with :- )

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    Thank's Brian


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    ·"Imagination is more important than knowledge..." ·· Albert Einstein
  • Capt. QuirkCapt. Quirk Posts: 872
    edited 2007-03-27 01:55
    Consider me, motivated
    Ken,
    ·
    We have different goals, You are working towards a "proof of concept" project, from the ground up. All I need is a test bed for smaller more specific testing·goals, which still parallel my airplane·projects.
    ·
    I found out a long time ago, the dyno doesn't replace ground testing. It's mainly used for verification of the ground testing results. Only after·preliminary testing is completed, can further improvements can be made with the use of a dyno efficiently.
    ·
    So my plans are to buy the·cheapest, small·50cc Chinese quad I can find. Convert it to·radio controll and my test bed will be complete. Along the way it would be fun to start adding Parallax accessories and turn it into a big SX BOE BOT

    Bill
  • Capt. QuirkCapt. Quirk Posts: 872
    edited 2007-03-27 02:10
    I have some 2300 rpm motors , I beleive that should put me in the roughly at 5mph
    I think its closer to 3.5 mph
  • Brian_BBrian_B Posts: 818
    edited 2007-03-27 02:23
    Capt. Quirk said...
    I have some 2300 rpm motors , I beleive that should put me in the roughly at 5mph
    I think its closer to 3.5 mph
    Good thing I don't work for nasa (was just doing the math in my head :- ) , just bought a pair of 5000 RPM motors on ebay for $8.00 a piece .

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    Thank's Brian


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    ·"Imagination is more important than knowledge..." ·· Albert Einstein
  • Capt. QuirkCapt. Quirk Posts: 872
    edited 2007-03-27 05:09
    5000/60 = 83.333333333333333333333333333333 RPS

    ·83.333333333333333333333333333333/20 (20 to 1 gear ratio) = 4.1666666666666666666666666666667 Rotations/sec

    4.1666666666666666666666666666667 * 2.6166666666666666666666666666667 (wheel circumfrence in feet) =

    10.902777777777777777749999999998 Feet/sec * .6818 = 7.4335138888888888888699499999988 MPH

    HAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA!!!!!!!!!!!

    But you'll be able to pull out tree trunks!

    I'll bet your pinion gear has more teeth than that. Really small gears are usally weak, 4 teeth just doesn't make sense.

    Post Edited (Capt. Quirk) : 3/27/2007 5:17:54 AM GMT
  • Brian_BBrian_B Posts: 818
    edited 2007-03-27 10:49
    Capt. Quirk said....

    I'll bet your pinion gear has more teeth than that. Really small gears are usally weak, 4 teeth just doesn't make sense.
    Didn't seem·right to me either , opened the case up and counted the gears . Stangest looking gears I ever seen , not sure what class to put them in . There really thick , about 1.75 inches.

    ·Also did some brian (brain) storming , I seemed to remember a really cool looking 1/2 hp , 12 volt dc motor I have laying around some where . You don't suppose I could use that for power generation and to start the motor too.... hmmm.

    Here's a rough white board drawing of where I'm heading with the frame , next step is cad ( cardboard aided design)


    p.s I think 7.5 mph·is a safe speed for now :- )


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    Thank's Brian


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    ·"Imagination is more important than knowledge..." ·· Albert Einstein

    Post Edited (Brian Beckius) : 3/27/2007 2:40:16 PM GMT
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  • Brian_BBrian_B Posts: 818
    edited 2007-03-27 18:19
    Couldn't find any cardboard :- )

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    Thank's Brian


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    ·"Imagination is more important than knowledge..." ·· Albert Einstein
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  • Brian_BBrian_B Posts: 818
    edited 2007-03-27 23:34
    I turned the frame over ,I think It look's better upside down .

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    Thank's Brian


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    ·"Imagination is more important than knowledge..." ·· Albert Einstein
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  • Ken GraceyKen Gracey Posts: 7,366
    edited 2007-03-27 23:39
    Funny how that worked out, but it seems more appropriate. Now it can carry a small child.

    I've also thought about using a DC motor as both a power generator and a starter. I think the challenge is that you need a non-geared motor for a direct connection to an engine to generate power, and you need a geared motor to start the engine. Maybe others can weigh in on this detail, but it's a darned good question you bring up for hybrid robots. I guess I could go and machine a big pile of parts to find out, but each time I "finish" a project I get more careful about getting excited ahead of time. The commitments are always bigger than the ideas!

    Ken Gracey
  • Brian_BBrian_B Posts: 818
    edited 2007-03-28 00:37
    Ken,
    ·Couldn't take the pressure , hooked the DC motor direct, took the smallest 12 volt battery I had and whoa la. One running (gas)·motor :- )


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    Thank's Brian


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    ·"Imagination is more important than knowledge..." ·· Albert Einstein

    Post Edited (Brian Beckius) : 3/28/2007 12:44:57 AM GMT
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  • Ken GraceyKen Gracey Posts: 7,366
    edited 2007-03-28 00:58
    Brian,

    Cool! What kind of current and voltage does the motor generate when you wind it up with the engine?

    What is the motor and engine shaft size and type? How did you couple them? Flexible coupling of some kind, or just a one-piece collar?

    Ken Gracey
  • Brian_BBrian_B Posts: 818
    edited 2007-03-28 01:22
    16 volts ,960 watts and 60 amps· ( I don't think it was wide open , but my meter couldn't take any more)·, Just made a direct·coupler quik to try it, I'm going to go with a flexable one. 5/8 shaft on engine and 5/8 on dc motor ( there might already be a step up bushing on this)


    p.s - kinda of hard to hold the meter ,the camera And motor control's at once :- )


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    Thank's Brian


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    ·"Imagination is more important than knowledge..." ·· Albert Einstein

    Post Edited (Brian Beckius) : 3/28/2007 2:04:12 AM GMT
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  • ChrisPChrisP Posts: 136
    edited 2007-03-28 04:49
    For a hybrid robot would it be realistic to go to a higher voltage electrical system, say on the order of 150-250 VDC? Brushless motors are getting very common and seem to make pretty efficient generators/alternators as well as considerable startup torque. That kind of setup would also generate plenty of AC allowing the use of larger scale servo motors for drive etc maybe, and if tapped into the AC side with a small toroid could recharge onboard batteries for the electronics... Just a thought.....
  • Brian_BBrian_B Posts: 818
    edited 2007-03-28 11:24
    ChrisP said...
    For a hybrid robot would it be realistic to go to a higher voltage electrical system, say on the order of 150-250 VDC?


    Thanks ChrisP,

    I think this whole subject needs a little more investigating , for this robot I'm going to stay with 12 volt ( all my parts are 12 volt ) . My plan right now is to build a "real" test stand and to try to graph some longer runs of the dc power plant . one curios note, the motor pulls really hard then really easy . I beleive it fully charges the battery and then the·dc motor try's to out run the gas engine· (might need a diode some place to prevent this).

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    Thank's Brian


    www.truckwiz.com

    ·"Imagination is more important than knowledge..." ·· Albert Einstein
  • ChrisPChrisP Posts: 136
    edited 2007-03-29 03:38
    Is there a circuit breaker somewhere that could be tripping and resetting? Whats the open circuit voltage of your motor/generator setup? Might want to be careful about boiling the battery off with voltage rise once its completely charged. Amperage will be determined by the torque applied, voltage by the rpm's (Within the ratings of the motors windings of course) For brushless motors its Back EMF· Volts per thousand rpm.

    Been kicking around back driving a brushless motor and using it as the high voltage AC supply to run a pair of small servo drives..... Say·3 amp rms 300 volt drives... Should get some serious power without the high current draw/heat/huge wiring etc while keeping the controllability of electric drive...
  • Brian_BBrian_B Posts: 818
    edited 2007-03-29 09:03
    ·This whole test caught me a little off gaurd , I thought I was just going to confirm that the motor would not start the engine ( I intentionally used the smallest and lowest charged battery I had to make sure I didn't get a start under too good of conditions). So needless so say I was ill prepared to take any kind of measurments when it did start . I had to "borrow" the watt meter from my wind generator to get the readings I did get(these reading where made hooked into my wind generators battery bank)·.I only really ran it for 30 seconds ,just enough to take a quik reading . Once I get this set up to do some real test I'll post the results . By the way, the motors on my axel's are 115 dcv .

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    Thank's Brian


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    ·"Imagination is more important than knowledge..." ·· Albert Einstein

    Post Edited (Brian Beckius) : 3/29/2007 9:25:02 AM GMT
  • Brian_BBrian_B Posts: 818
    edited 2007-03-29 12:46
    ...Anyhow , moving along with the robot . Here's the design I decided on ,front "wagon" will be 16 inches long and rear "wagon" will be 20 inches long and the 2 will pivot in the center . My next step is to cast 4 axel mounts & the center pivot.


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    Thank's Brian


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    ·"Imagination is more important than knowledge..." ·· Albert Einstein

    http://www.diycalculator.com/subroutines.shtml· My favorite website ( Bet you can't guess why)


    Post Edited (Brian Beckius) : 3/30/2007 12:47:56 PM GMT
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  • Mr. RichardMr. Richard Posts: 51
    edited 2007-03-29 17:32
    Brian,

    How do you do your castings?

    I have used perma-bond sand packed around a Styrofoam form. When you pour in the molten material, the foam burns away. I have had great success with this, but am always looking for new ways



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    Magic Smoke Theory of Electronics –
    Inside every electronic part there is magic smoke.
    The magic smoke is what makes everything work.
    If you release the magic smoke, the part stops working!
  • Brian_BBrian_B Posts: 818
    edited 2007-03-29 22:41
    Mr. Richard,
    I'm kind of a little old school when it comes to casting , I use petro-bond and wood patterns . I would like to look into air set sand (you can cheat a little and use a cnc mill to make patterns) . Seem's like a waste ,but it adds a little factory look to it.

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    Thank's Brian


    www.truckwiz.com

    ·"Imagination is more important than knowledge..." ·· Albert Einstein

    http://www.diycalculator.com/subroutines.shtml· My favorite website ( Bet you can't guess why)


    Post Edited (Brian Beckius) : 3/30/2007 12:48:55 PM GMT
  • Brian_BBrian_B Posts: 818
    edited 2007-03-30 01:52
    Here's axel mount 1 of 4· , center has to be machined out and then split. I'm going to cnc·machine one of these brackets··just to see how it looks compared to the cast one.


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    Thank's Brian


    www.truckwiz.com

    ·"Imagination is more important than knowledge..." ·· Albert Einstein

    http://www.diycalculator.com/subroutines.shtml· My favorite website ( Bet you can't guess why)


    Post Edited (Brian Beckius) : 3/30/2007 11:39:43 AM GMT
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  • Brian_BBrian_B Posts: 818
    edited 2007-03-31 04:32
    I'm trying to check in once a day to let everybody know my progress . Raining out today, so I can't pour metal· . I am working on CNC version of the bracket ,really close to making chips fly if I could get some fillets to work out.

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    Thank's Brian


    www.truckwiz.com

    ·"Imagination is more important than knowledge..." ·· Albert Einstein

    http://www.diycalculator.com/subroutines.shtml· My favorite website ( Bet you can't guess why)


    Post Edited (Brian Beckius) : 3/31/2007 4:39:18 AM GMT
  • Brian_BBrian_B Posts: 818
    edited 2007-03-31 12:56
    Heres some photo's of my multimillion dollar robot shop :- )


    ps. Everybody can thank lostcauz for turning these pictures right side up :-)



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    Thank's Brian


    www.truckwiz.com

    ·"Imagination is more important than knowledge..." ·· Albert Einstein

    http://www.diycalculator.com/subroutines.shtml· My favorite website ( Bet you can't guess why)


    Post Edited (Brian Beckius) : 3/31/2007 7:43:49 PM GMT
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  • ChrisPChrisP Posts: 136
    edited 2007-04-01 06:16
    Brian, actually the reason I was asking about higher voltage was two fold. I've come into posession of some Allan Bradley servo motors, 3 phase brushless DC, and have a couple of very small servo drives to operate them.

    One approach was to generate the AC power to run the drives from one of the motors, and then have robot drive from the brushless servo motors, with a very small on board battery to run the electronics charging from a small transformer perhaps. The other that I simply dont have the electronics knowledge for is generating high voltage DC and then using a PWM output to regulate the voltage down to something useable. Mainly because the brushless motors seem to be better paired with small 2 cycle engines rpm wise. 4,000 - 6,000 rpm small motors are pretty common. Just not sure how the PWM would work as a voltage regulator. Also no parasitic losses from the fields of an alternator.....





    Chris
  • Brian_BBrian_B Posts: 818
    edited 2007-04-01 13:39
    Chris,

    ·I'm not really comfortable working with AC And higher voltages , but I'm sure there's sombody out there that should have a answer for you.



    Heres some sensor array info for robot. Also my newest axel bracket ,still has a little twist (arggg !, I remember why I like casting : -) I've also included a photo of the brackets home.


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    Thank's Brian


    www.truckwiz.com

    ·"Imagination is more important than knowledge..." ·· Albert Einstein

    http://www.diycalculator.com/subroutines.shtml· My favorite website ( Bet you can't guess why)


    Post Edited (Brian Beckius) : 4/1/2007 2:46:46 PM GMT
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  • PARPAR Posts: 285
    edited 2007-04-02 08:24
    Brian Beckius said...
    Heres some photo's of my multimillion dollar robot shop :- )
    Your shop must be equipped with one heckuva vacuum cleaner !! Is that what you spent the millions on?· There's not a spec of metal toolings/shavings anywhere????
    :>)
    PAR
  • Brian_BBrian_B Posts: 818
    edited 2007-04-02 12:02
    I should have a big mess to show you tonight . My old DOS/cncpro computer took a dump . I switch over to MACH3 controller software this weekend. It would only run 1000 lines of code until I received the registration code and I'm happy to say I just received it in a E-mail.

    Ps. My shop is in the garage and my wife has yelled at me more than once about metal shavings in the house , so I vacuum pretty heavy smile.gif

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    Thank's Brian


    www.truckwiz.com

    ·"Imagination is more important than knowledge..." ·· Albert Einstein

    http://www.diycalculator.com/subroutines.shtml· My favorite website ( Bet you can't guess why)
  • T0mT0m Posts: 124
    edited 2007-04-02 15:34
    Brian,
    I love the shop. Looks alot like mine except mine is a big mess. Chips every where....lol. I use mach 3 and if you have any questions about it I may be able to help. If you need the taig xml for setting up mach3 let me know.
    Tom
  • Brian_BBrian_B Posts: 818
    edited 2007-04-02 15:51
    Tom,
    Thank's ,I'll let you know if I have a problem . where did you get the tracks on your robot from ?

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    Thank's Brian


    www.truckwiz.com

    ·"Imagination is more important than knowledge..." ·· Albert Einstein

    http://www.diycalculator.com/subroutines.shtml· My favorite website ( Bet you can't guess why)


    Post Edited (Brian Beckius) : 4/3/2007 12:17:51 AM GMT
  • T0mT0m Posts: 124
    edited 2007-04-02 17:52
    Hi Brian,
    I ordered the tracks from Radio shack. They are spare parts for a rc truck they sold a few years back. The parts needed to adapt the mattracks to the boe bot were designed with turbocad cam and made on my taig mill running mach3
    Tom
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