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Building my first Elev-8. Have a few questions... — Parallax Forums

Building my first Elev-8. Have a few questions...

Don MDon M Posts: 1,647
edited 2012-12-17 13:06 in Robotics
1. I plan on using 2 LIPO batteries, SkiLipo 30C 4000mAh. Do I connect the batteries in parallel and connect to all 4 ESC's together or split them up and use 1 battery per 2 ESC's?

2. Is it a good idea to use the quick disconnects on each ESC power leads versus just soldering them? I already have them on the motor leads between ESC and motor.

3. I plan on mounting the batteries on the underside of the Elev-8. Is that a good place for them?

I'm sure I'll have more questions.

Thanks for now. Excited to see this thing fly!
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Comments

  • W9GFOW9GFO Posts: 4,010
    edited 2012-04-17 22:47
    I mount my battery on the underside, no problems.

    Parallax-EXPO-2012-9588-L.jpg
  • ercoerco Posts: 20,255
    edited 2012-04-18 00:12
    Wow Don M, you don't waste any time! Great to meet you at Expo and happy to hear you're chomping at the bit to get into the air. It'll be June-ish before I even open my ELEV-8's box, between honeydos owed and our imminent family trip back east. Just keep your props pointing skyward! :)
  • dmagnusdmagnus Posts: 271
    edited 2012-04-18 09:07
    Don M, another Don M here. I wanted to introduce myself to you when I saw your nametag, but something got in the way and I didn't do it. Are you the guy who is using the Hoverfly Pro board? If so, I'm in the initial test flying (and crashing) mode and will be glad to pass on anything I have come across.
    As to your questions:
    1. I only use one battery, but may consider using two in the future. If so, I think I'd put them in parallel and hook all 4 ESC's together. I'm a little leery of having separate power for pairs of ESC's, but someone on here will jump in if I'm wrong.

    2. In my opinion, the more connectors you have, the more possibility for problems.

    3. My battery is on the bottom - no problem. That was necessitated because the Pro board is smaller so I don't have room between the standoffs on top for a battery.

    I also installed a switch on the battery so I can turn the whole thing off quickly without yanking on the power leads. My motor leads are soldered to the 13" leads through the arms. Then they have bullet connectors to hook them to the ESC's. The ESC's power leads are soldered together to single lead for each (+ & -) and they have bullet connectors that match the battery ones.
  • W9GFOW9GFO Posts: 4,010
    edited 2012-04-18 11:59
    dmagnus wrote: »
    That was necessitated because the Pro board is smaller so I don't have room between the standoffs on top for a battery.

    I have the Sport, Pro and Open versions of the HoverFly boards. The Pro is the largest, with a larger spacing between the mounting holes. Are you using some other board?
  • JasonDorieJasonDorie Posts: 1,930
    edited 2012-04-18 13:59
    I mount my batteries on the bottom, and have never had a problem. I use either a single 4200mAh, or a pair of 2200mAh batteries in parallel. It's best to run them parallel and tie all the ESCs together, that way the power dies for all of them at roughly the same time. :)

    As for mounting the quick-connects on the ESC to battery side, it helps when mounting the ESCs or if you ever have to disassemble the thing. You have more freedom to move your wiring around if you use the EC3 connectors on the battery leads, and they take a good bit of force to disengage, so I'm not worried about them coming loose in flight.

    Jason
  • dmagnusdmagnus Posts: 271
    edited 2012-04-18 16:28
    No, my bad. But there is still no way I could bet a battery between the mounts. Of course, I somewhat modified it to accomodate the Pro board. I'm also sorry I didn't get to introduce myself to you at the Expo. There was just so much going on and you were really busy! Great job, by the way.
  • Don MDon M Posts: 1,647
    edited 2012-04-19 17:12
    Ok thanks for the suggestions everyone. I have everything wired up and so far it passes the tests! The most tedious task I find is the manufacture of the primary power harnesses. Working with those heavy gauge wires is tricky. I spent quite a bit of time laying out the wire routing and was very meticulous in the fit and finish of the harness and connectors. It looks good. Good solid solder connections.

    Now to figure out the radio setup etc. I'll be giving her a "whirl" this weekend....

    @Erco- It was a pleasure meeting you and W9GFO this past weekend. Wish we were all closer to meet-up several times a year.
  • StempileStempile Posts: 82
    edited 2012-04-19 22:23
    Hey Don - I just flew the ELEV-8 that I got at the Expo (converted winnings from the LFO contest) as for the first time late tonight. At first had issues with the motors pulsing when I throd up. Turns out I forgot to change the GEAT ADJ Travel to -25/+25. After that I was able to hover. By that time it was already 10pm so the LEDs were working well. Even so late, I still managed to attrack the attention of a couple neighbors.

    Its a little jittery, not as smooth as I was expecting. I spent a bunch of time making sure the props were balanced before starting, so now I am thinking I might have the HooerFly screwed down to tight and I am getting vibration on the gyro? Suggestions any one? I have the Sport so I tried both the AP and Sport firmware. Did you find it a little twichy? I am going to watch a few of the youtub videos and compare now that I some perspective.

    ms
  • W9GFOW9GFO Posts: 4,010
    edited 2012-04-19 22:33
    I have my gain set at 20%. Rick lowered his to 25% from 35% (I think) and liked it better. I've learned that low gains are much smoother than high gains.
  • StempileStempile Posts: 82
    edited 2012-04-19 22:44
    W9GFO wrote: »
    I have my gain set at 20%. Rick lowered his to 25% from 35% (I think) and liked it better. I've learned that low gains are much smoother than high gains.

    are you talking about just the 'GEAR' gain? What is that doing exactly? I thought it would just have impact if I was engaging the switch? Also though I would need the MAX sonar sensor, I don't have one hooked up, so that last port on the receiver size is empty.
  • StempileStempile Posts: 82
    edited 2012-04-19 22:48
    Answered my own question:
    Page 49 of HoverFly Sport Manual

    Tuning Gain
    The Primary Gain value is the EPA value that you can edit on your transmitter when the Gear switch is set to Altitude Hold disabled. The Primary Gain value is used by the HoverflySPORT to increase the sensitivity of the control algorithm. In general a value that is too low would make the controls feel “mushy” and the aircraft would be difficult to fly. A value that is too high would result in quick oscillations of the aircraft and once again it would be difficult to fly. Every aircraft will have a slightly different gain and the user must adjust the Primary Gain to find the “sweet spot” where it feels best for their type of flying.
    Begin tuning the Primary Gain starting with a low value of gain around +10 to +25 (as shown in Fig. 12). With the aircraft on the ground and armed increase the throttle until it just lifts off. If it is difficult to control or mushy increase the gain by +10 and repeat the procedure. Once you can safely lift off and hover observe the aircraft and look for oscillations. This is very similar to a remote gain on a helicopter where too high of gain will result in tail twitching. The Primary Gain should be increased to a value just before the oscillations begin.
    Once you become more experienced flying with the HoverflySPORT, you will be able to adjust your gain using the Gear EPA for Primary Gain during flight.
  • Don MDon M Posts: 1,647
    edited 2012-04-20 11:38
    Well after a bit of phone help from Nick @ Parallax I was able to get her off the ground. Still need to do some fine tuning of the settings. It wants to take off in one direction besides straight up. Thankfully it doesn't want to just flip over. I had it going a few times and then I was too quick to shut down the throttle and it landed on one of the props. You know the rest of the story.....

    Off to the hobby store to see if they carry these type of props otherwise it's an order to Parallax for a "crash kit". Wish I had picked one up last weekend. Must have thought I wouldn't break anything.. :)
  • StempileStempile Posts: 82
    edited 2012-04-20 14:04
    I cheated, had practice from flying a 450 CP heli... it is different enought. Trick is not to panic and drop the throttle. Its tempting to want to stop everything to get your perspective back in order.

    I scruffed up the tips of a couple props, but didn't cause much damage. The slow stick props are very forgiving, its great!!! Whacked the heli blade and you end up bending parts else where in the craft.

    I have a couple Hobby King Nano-Tech 4500 packs. They are charge and ready to fly again tonight!
  • Don MDon M Posts: 1,647
    edited 2012-04-20 14:25
    I found some props at a HobbyTown store. Put on the spare and flew again. I loaded the AP version of the firmware after talking to HoverFly. They said it would fly a bit more stable for just starting out. It does seem less less touchy.

    You are right about dropping the throttle. That's just what I seem to do when it starts going somewhere that I don't want it to. I drop the throttle and then it too drops from the air. Just broke a second prop. Gonna take a bit of practice.....
  • StempileStempile Posts: 82
    edited 2012-04-20 14:52
    Until you get use to the controls, tether it. You could setup a counter balance to include lift + pitch and roll.
  • StempileStempile Posts: 82
    edited 2012-04-20 21:39
    Lost orentation, reconfirm that 90 degree to the ground won't produce any lift. I came down bu recovered mostly before grounding, only lost 1 prop but did crack a main plate on the bottom. Before got 4 batteries worth of flight time in before. When learning to fly the heli I was really conservitve, wasn't much fun. With the Elev-8 having lots of fun and it really does attrack a lot of attention from kids and adults alike!!

    Hey Nick or Ken - can I buy just the plastic plates of the ELEV-8? Not a standard crash pack item... Looks like its nomy cracked plate isn;t to bad, but it might fail in the future.
  • dmagnusdmagnus Posts: 271
    edited 2012-04-21 16:40
    Got in about a half hour flying today before the rains came. I have my primary gain(Pro board) set pretty good now to the point where it's pretty easy to fly. It's set at 23. I have everything plugged in to the proper places, altitude hold gain set at 25. I can take off, fly around and then come back to a hover at about 2 1/2 feet of altitude. Flip the autolevel switch (gear) and the quad does a perfect flip to the left, landing on it's top - the video is hilarious. No problem getting out of the throttle so it just gently land's on it's back in the tall grass. In two batteries worth (about 14 min each), I tried it about 5 times. Same thing every time. I tried lower gain and higher gain and 23 seems to be comfortable to fly. I'm getting flipping discouraged! :frown: I don't know what else to try so I guess I'll call Hoverfly on Monday. I'm going to go out and flip it a few more times tomorrow and just generally fly around for awhile, maybe I'll come up with a gain that works...
    Don
  • dmagnusdmagnus Posts: 271
    edited 2012-04-22 14:12
    Got in about 3 batteries worth of flying today. I settled on 28 as a good gain setting. Recomfirmed that everything is hooked up properly and even took it outside with the computer hooked up to check the GPS for signal, etc. Really cool, the window in the Setup app comes up with a Google map of your location when the GPS acquires. Showed me standing outside on the front side of my house. Very accurate.
    Went out and flew and it is still flipping whenever I try any of the advanced features. Obviously, if Autolevel won't work, then nothing else will either. I finally broke a prop after about 11 flips - not bad. I'm going to call Hoverfly tomorrow. Other than that, it flys really nicely on a gain setting of 28. 25 would probably work fine, too, but anything over 30 makes it shaky.
  • dmagnusdmagnus Posts: 271
    edited 2012-04-23 16:43
    Finally solved the flipping problem. As it turns out, I had everything set up properly, but when I did my calibration (accelerometer) way back when, I had the quad in front of me, at a right angle to the computer. Why this makes a difference is beyond me, but the instructions I finally found (though another forum) here: https://hoverflytech.zendesk.com/entries/21202158-how-to-setup-autoleveling states that you should have the board (quad) between you and the computer screen when manipulating it for the calibration. It also appears that clearing out the settings, and unplugging the USB cable, plugging it back in, then doing the calibration is important. Go figure. Anyway, I took the ELEV-8 out in the yard and got it into hover, flipped the Autolevel switch and VOILA, it worked! Then I proceeded to mess around and managed to really land it hard, breaking THREE gear legs. I've only got two in the crash pack so I'm ordering more. But we're making progress!!!
    I guess my next question is this: Now that autolevel works, it seems really mushy to fly - to overcome the autolevel - I wonder which way I should move the gain to make it less so or should I leave it well enough alone and live with it...
  • JasonDorieJasonDorie Posts: 1,930
    edited 2012-04-23 17:45
    If I'm not mistaken, the gain in auto-level is independent of the gain in "regular" mode. Just change the OTHER endpoint setting (not the one you have at 25-ish). If that setting works well for you on that end, my *guess* is 75 will work well for the other side. What's it set to now?
  • dmagnusdmagnus Posts: 271
    edited 2012-04-24 06:30
    Right now, both gains on the gear switch ("regular" and autolevel) are set to 28. So you're saying I should go to 75 on the autolevel one? I'm confused, is higher gain LESS control by the board or MORE? They recommend starting with both levels at 25. They use a different radio in their example that has a positive and negative side - the DX8 has only positive, controlled by where the switch is set. (pp 56-58 in the HFPro manual) I have mine set to 28 with the switch in the "0" or "off" position and 28 with it in the "1" or "on" position. It flys ok without autolevel being turned on, but is slightly squirrely. When I engage autolevel, it holds pretty well, but needs a lot of stick to make it move -very "mushy". When I get more gear legs (oops) I will do some more experimentation.
  • JasonDorieJasonDorie Posts: 1,930
    edited 2012-04-24 09:24
    Ahh, ok - if your radio has two different switch settings, and they're both from 0 to 100, then you're correct to use the same (or close to it) value for each side. Some radios use the range 0 to 100 to represent the whole range of an input, so 0 is one side, and 100 is the other. On a radio like this, my advice would be correct - 25 on one end would equate to 50% of the way from 0 to the midpoint, and 75 on the other side would be halfway between 100 and the midpoint. It'd be nice if they'd settle on a way for all of them to work. :) (and hopefully my explanation here hasn't made anything more confusing)
  • dmagnusdmagnus Posts: 271
    edited 2012-04-24 11:11
    Yup, I understand. And thank you for your help.
    'nother question. Can you epoxy delrin? one of my gear legs is broken right where it attaches to the arm. It looks like a clean break and I'm wondering if I couldn't epoxy it to hold it until I can get more legs. I have two in my crash pack and that would get me flying sooner. But, as I remember from working with delrin bearings on sailboat hardware, I don't think much of anything will stick to it. Might give it a try anyway...
  • SRLMSRLM Posts: 5,045
    edited 2012-04-24 12:06
    http://www.rebreatherworld.com/home-build-rebreathers/16952-glue-for-delrin.html
  • Nick ErnstNick Ernst Posts: 138
    edited 2012-04-25 13:52
    Dmagnus,
    I have a Pro board on my Hex, and my "Free Flight" gain is set to around 29%, and my Autolevel is set to 26%. When flying with Autolevel, you are really just fighting the HoverCore system. If you have your "Auto Level" gain set to how you like it, I would leave it alone before you get over ambitious and something catastrophic happens to you quad. (I've gotten over amibitious before, that's why I said that!)

    -Nick
  • dmagnusdmagnus Posts: 271
    edited 2012-04-26 05:22
    Thanks, Nick. As soon as I can get some replacement gear legs, I'll do some more experimentation. I didn't think of setting them different from each other, but maybe I should just leave it alone until I get more proficient.

    SRLM: I don't think the epoxy worked so I'll try some plastic glue next. Gotta get some gear legs!
  • Don MDon M Posts: 1,647
    edited 2012-04-26 11:47
    When changing the GEAR setting (I have a DX6I radio) do you need to power down / up the quad, the radio or both? For instance if I was flying my quad and wanted to make a GEAR setting change I would land the quad, change the setting in the radio and then do I need to power down/up anything for the settings to take effect?
  • JasonDorieJasonDorie Posts: 1,930
    edited 2012-04-26 12:36
    From what I understand, the settings can be toggled in flight. Best to make sure you have both configured properly before doing that, though. :)
  • Don MDon M Posts: 1,647
    edited 2012-04-26 17:29
    JasonDorie wrote: »
    Best to make sure you have both configured properly before doing that, though. :)

    That is my question- when doing the configuration settings (when the craft is not flying but powered on) does the power need to be toggled off/on on the radio and/or the quad for the setting to take effect?
  • dmagnusdmagnus Posts: 271
    edited 2012-04-27 06:44
    In my experience, you do not have to power off/on the craft. You are making changes to the transmitter, not anything on the craft, so they take effect immediately.
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