Woulld like to repeat basic stamp potentiometer servo control using propeller s

pflynn

Folks,

I have a propeller demo board, standard parallax servo and 10k variable pot and·the servo circut setup on the bread board (like the basic stamp lab- what's a microcontroller).

Looking for example code or someone interested in these issues:

I have tried to use pot/RCtime spin and one of the servo (victor? speed controller·and or ??servo 32)·controller example codes to try to repeat the basic stamp potentiometer control using a propeller stamp.

I get the potentiometer read out ( nice TV out) with one·code and a servo controlled with the other code. When I try to use them together it·doesn't seem to update the potentiometer position when I try referencing pot in the servo controller code or vise versa. Maybe some global var or data·that changes every cycle is not updated·and the other code maybe not looping through it?

I'm looking for a better starting place example. I just want to controll several speed controllers (Jeti opto 99 and AXI 6345 motors) with one throttle control potentiometer·or other·better position sensor for this function. My basic stamp·can do one controller just fine but when I try to add more controllers/servos in, the timing is slowed? and then the speed controllers don't function anymore (initializing min max set points, beeps etc.), but the·multiple servos still work. Hope using one cog per controller could get around this.

Then real·work on differential thrust problems (balance)·between the·6 to 12 motors on different sides of an aircraft. The jeti motor controllers may give me in flight information on their status and·or a vibration/tachometer sensor to look for failures then shutdown failing motor·and then cut back the other matching·oposite side motor to compensate. Trying to·minimize wild yawing from motor/propeller·failures.

Last is to graphically represent all·this in the cockpit display·using the TV out or a·small·LCD screem.

My searches are not finding much in the forums under potentiometer, speed controller, servo, ESC.


Thank you,

Peter.

Mike Green

As with any question like this, you'll need to post your code (as an attachment to a message please ... not cut and paste) and at least describe how you have things connected. A schematic would be best.

W9GFO

Here is a section of code from my Servo tester with the non essential bits removed.

PUB adjMs  | delta, old, workVal, value, potValue[noparse][[/noparse] 30], i, j


  repeat i from 0 to 29                        ' Fill RC array with values
    potValue[noparse][[/noparse] i] := RC.main

  repeat

    repeat i from 0 to 29                    ' running average
      potValue[noparse][[/noparse] i] := RC.main
      workVal := 0
      repeat j from 0 to 29
        workVal += potValue[noparse][[/noparse]j]
      value := workVal/30

      uS := center - ((value/2) - center) + potCal       'pot cal is figured out in the setup routine

     delta := uS - old

      if || delta < 2
        uS := old

      uS <#= uS_Max
      uS #>= uS_Min

      GroupOut(Servo_Pin1, Servo_Pin6, uS)
      GroupOutR(Servo_Pin7, Servo_Pin12, uS)              ' inverts the pulse width so that pins 7 -12 are reversed

      old := uS

Rich H

hover1

Peter,
If you are familiar with BS2 programming, have a look at this object. Implements BS2 functions in Spin :

http://obex.parallax.com/objects/30/

You could start using your BS2 experience to develop something, but it sound like a very ambitious project.

6- AXI 5345 motors? (I'm assuming 6345 was a typo?). Sounds like a 100lb+ plane. So that would take 6 Spin 99 Speed Controllers. To recover from a motor failure, must have 2-axis accelarometer, (or gyro), to indicate yaw fluctuation. This would mean at the very least of controlling a bank of three speed controllers for each side to recover from a motor or prop failure.

The problem I see with the Jeti flight information system, is that it sends the information down to the RC transmitter. I don't know know if that information is available directly at the receiver in the plane for the propeller to pick up.

As far as Graphical Output, see Old Man Earl's contributions:

Video Overlay:
http://forums.parallax.com/forums/default.aspx?f=25&m=348906

Auto Pilot:
http://forums.parallax.com/forums/default.aspx?f=15&m=339513&p=2&ord=d

There is plenty of information for servos available in the Propeller forums. ESC's are nothing more than servos if you are just giving them commands and not expecting anything from them.

Try this search method:

http://search.parallax.com

Hope this information was of value.

Regards,

Jim

pflynn said...
Folks,


I have a propeller demo board, standard parallax servo and 10k variable pot and the servo circut setup on the bread board (like the basic stamp lab- what's a microcontroller).



Looking for example code or someone interested in these issues:



I have tried to use pot/RCtime spin and one of the servo (victor? speed controller and or ??servo 32) controller example codes to try to repeat the basic stamp potentiometer control using a propeller stamp.



I get the potentiometer read out ( nice TV out) with one code and a servo controlled with the other code. When I try to use them together it doesn't seem to update the potentiometer position when I try referencing pot in the servo controller code or vise versa. Maybe some global var or data that changes every cycle is not updated and the other code maybe not looping through it?



I'm looking for a better starting place example. I just want to controll several speed controllers (Jeti opto 99 and AXI 6345 motors) with one throttle control potentiometer or other better position sensor for this function. My basic stamp can do one controller just fine but when I try to add more controllers/servos in, the timing is slowed? and then the speed controllers don't function anymore (initializing min max set points, beeps etc.), but the multiple servos still work. Hope using one cog per controller could get around this.



Then real work on differential thrust problems (balance) between the 6 to 12 motors on different sides of an aircraft. The jeti motor controllers may give me in flight information on their status and or a vibration/tachometer sensor to look for failures then shutdown failing motor and then cut back the other matching oposite side motor to compensate. Trying to minimize wild yawing from motor/propeller failures.



Last is to graphically represent all this in the cockpit display using the TV out or a small LCD screem.



My searches are not finding much in the forums under potentiometer, speed controller, servo, ESC.





Thank you,



Peter.

pflynn

Thank you all for replying..

Here are versions of the code I was working with. The one with the date on it was the last try. I have to sneaker net it off of another system I have upstairs in a multi purpose unfinished (junk)·room. The·system the kids don't want to work on..

There is also a picture of my setup and a·very small picture·of the air plane design.

Yes, The motor is a AXI 5345 -16·with a spin opto 99 controller at 48 volts. This motor sings at 36 volts. I have not test it at 48 volts·yet.

yes, I agree it's ambitous dream at this point. I have to start here first. If the motor control doesn't work
then the rest is not important. The aircraft design involves an 6061 T6 al. tube frame with a kevlar shell.
It would be·smaller·than·a bd5. but lighter with graphite/carbon wings.·Less than 400 pounds. The 12 motors are mounted in twos on the wing tips fore and aft·and elevator and canard surfaces fore and aft. It would use·Lithium batteries. Think bicycle scale.
They would counter rotate and try to eliminate ( may create..) wing tip loses. The goal would be to fly at 160 to 190 mph for 10-15 minutes to comute a 40 mile distance.

I will look at the new searches. and the Display information.

Thanks again,

Peter.

hover1

Peter ,
Bede meets Rutan, I like.
Are we talking unmaned vehicle, I hope?
Jim

BADHABIT

I hope you got a $h1t Lo@d of Milliamp Hours

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
BH

pflynn

Jim,

What would be the fun of all the hard work, to let a propeller stamp fly it. Yes, I understand your point. Safty first. It's going to be a long road before that time. There will be a lot of testing to failure. Frozen chickens, ice, garden hose spray, etc.. : ) I do plan on a BSR? chute system. Large rudders ,fuse an tail, And there always the master power switch. glider training and 3rd parachute jump.

BH.

The batteries are mounted near the motors with connections to their cousins on the other side for power balance. If I get lipos, the heat may be a problem with the graphite /carbon composite. Duracane? is one of the few resins to take temp above 200 F may have to transition back to some other material at the tips. S-glass and duracane can take some heat. Amp minutes is what I need. ~48 volts at 90 amps for 10-15 minutes per motor. Well that's next on the list.

Peter.

W9GFO

I made a very short hop in an electric powered paraglider on 17 Dec 2003, we think we were the first to fly an electric ultralight. It used an Etek motor swinging a 42" prop. We were pulling 8 kilowatts out of five 40 cell battery packs for that very short flight. Later we added 120 more cells for a boost up to 11 kw but we had an inflation failure with messed things up a bit.

My point is, for an electric powered aircraft you could drop that Etek (or a newer more efficient motor) in a Quickie - and off you go!

Rich H

SamMishal

Please Have a look at this posting

http://forums.parallax.com/showthread.php?p=825226

Sam

pflynn

SamMishal,

Thank you for the code examples, This should give me a good start. I will work with this and the Rich H. code.

Rich H.,

Sorry I didn't get back with you, I just cut and pasted all the info this morning and realized you were the first to respond with the code example. I am interested in your ultra light experience as well. inflation problem? Weight? What was the dry weight without the motor and what was your weight with the motor and batteries?

Hover1,

I have your links, I will try and go through those this weekend.

I picked the AXI 5345 because it looked like it had a nice power to weight ratio. Though not tested to 48 volts yet. Also I could distribute the weight around the aircraft better than just the fuselage. I don't care about high roll rates. I have 16 hours in a pitts S2 (muscle)and about 3 hours in the Christian eagle (like power steering) with instructors. I don't have enough tail drag time for these squirly aircraft on landings.

Peter.

W9GFO

pflynn said...
I am interested in your ultra light experience as well. inflation problem? Weight? What was the dry weight without the motor and what was your weight with the motor and batteries?

All up weight was right around 170 lbs. The batteries weighed 55 lbs, for the flight in the picture, later we added 22 lbs more. The trike frame was made out of tubing from old hang gliders and the paraglider harness hung inside the frame. The prop guard was made out of old hang glider battens (1/2 aluminum tubing) and was only intended to keep the lines away from the prop. The motor was an 8 hp Etek pancake style motor which swung a 42" wooden ground adjustable prop - direct drive. We measured 100 lbs of thrust for six minutes. We used a 300 amp controller made by Axe. The wing was an Advance Epsilon 3 - because that's what I had.

The inflation problem I referred to was what destroyed the prop and the prop guard. We had several helpers who all wanted to help with the launch. They insisted that the best thing to do was to hold the wing at chest level while I hit the throttle. This mainly acted as a huge air brake. I explained that it would be better to lie it on the ground and let it be snatched up into the air just as is done when foot launching. After exactly one attempt doing it my way they went back to holding it.

So what happens is the wing kind of wallows back and forth trying to get up overhead while I'm trying to steer the trike with my feet, hold the throttle and steer the nearly non responsive wing (which is behind me). In the last attempt the wing pulled too far to one side, flexing the guard and then catching the propeller. It made quite an impressive noise, the prop exploded upon impact with the guard and many of the lines were cut, bits of wood everywhere.

I would have preferred strongly to have used a hang glider instead of a paraglider. The problem was that my hang glider was rated at just a little more than my hook in weight so using it to lift an additional 170 lbs was out of the question. I had the paraglider already and we were pressed for time in order to make the Dec 17 goal, it was already November.

It would be a lot easier to do this now. There's at least one giant size brushless motor out there now but I can't remember the name, I think it is four pounds and puts out 10 - 14 hp. LiPos have come down in price drastically. Our power system weighed right near 100 lbs - today it could be around 40 lbs. And I would definitely use a hang glider instead of a paraglider!

The picture below was taken 100 years to the hour from the Wright Bro's first flight. We managed to get about four feet off the ground for 50 or so yards that day. A few weeks later we tried again with more batteries and that is when the accident happened.



Rich H

pflynn

Rich,
Thanks for the information and story. I don't have any experience with parasails. Seem like a workable Idea. I looked at the etek a while back for an electric go cart for the kids. Seemed expensive for me at the time. I have run across a electric sail plane. The manufacture didn't think it would cruise sustained at ~100 mph and was not designed with that in mind. They rated the motor in KW? By the way I hooked up the AXI 5345 and spin 99 opto to my basic stamp setup. Had to change timing to 24 degrees, 8 hz, aircraft outrunner, auto set, monitor timing on with the jeti box. I runs great with no buz saw sound at 50% & 90% power which had killed the ph0enix HV110 esc with the AXI 5345 three times. I did have to run it with a smaller prop though. My 22 inch 14 pitch had a crack in it. So I don't have any temperature/load information yet.

Folks,

Anyway, I hooked up the propeller stamp and loaded SamMishal's code (flipped the pinouts 0,1) and it worked, just the servo was eratic on the ends (min and max pot positions, scaling problem with my setup).

Is there a similiar Debug option like in the basic stamp to see the values of RCtime variable print to screen.

I had the video out working with the RCTIME_foreground DEMO_20090525.spin and could see what was getting output. I will check the capacitor and resistors and see what is different. Then maybe modify the code to use video out. I looked in the manual for Debug and print statement ...

Would like to see the output of PulseWidth and RCTime in this line:

PulseWidth:= 500+RCTime*21000/5425/10

I might be able to substitute this code into the RCTIME_foreground_DEMO_20090525 code and see it in video out and tweek it.

Thanks,

Peter.

pflynn

Folks,

I didn't see this little detail in the code.

To determine the range of the RCTime use the example │
│ program given in the Object documentation which uses │
│ Parallax Serial Terminal to show the RCTime value.

I will try this out.
Sorry,

Peter.

PS: I use 48 volts last night to test the AXI 5345 and spin 99 opto.

SamMishal

pflynn said...

I didn't see this little detail in the code.

To determine the range of the RCTime use the example │
│ program given in the Object documentation which uses │
│ Parallax Serial Terminal to show the RCTime value.

I will try this out.

Hi Peter,

How did it work out for you? Please let me know.


For the reasoning behind the formula please see this posting:

http://forums.parallax.com/showthread.php?p=825226


Regards

Samuel

Post Edited (SamMishal) : 7/27/2009 4:24:50 AM GMT

SamMishal

W9GFO said...
The picture below was taken 100 years to the hour from the Wright Bro's first flight. We managed to get about four feet off the ground for 50 or so yards that day. A few weeks later we tried again with more batteries and that is when the accident happened.

Hi Rich,

This is very very cool stuff......


Samuel
·

pflynn

Samuel,

I had down loaded the Parallax Serial Terminal but had trouble seeing output. The problem was my old version of the
propeller editor. I have down loaded the latest and just need to install it and try again. I got your information.
Will report back.

Thank you very much,

Peter.

Sigma X

has this project been done is there any code available?
the only difference is that i'm tring to control 5 servos with 5 different
pots

Post Edited (Sigma X) : 7/6/2010 1:53:36 PM GMT