First Tricopter AP platform - help would be nice :)

[makattack]

I'm glad to hear you've sorted out your tricopter! Yeah, what a lot of people forget with these things is that they aren't the same as fixed wing craft with more elementary electronics. You actually have a flight computer onboard and it's trying to stabilize flight for you. One needs to test the input commands result in behavior that you'd expect and also test that external influences/un-commanded forces on the airframe results in the opposite to counter the external forces.

Similarly, I think a lot of people who come from fixed wing or even heli RC, thinks they can just program their TX, taking advantage of expo, curves, etc, and think their computer driven controllers allow, forgetting that this actually works against them for better flight characteristics. All the programming and configuration should be on the flight controller for multirotors, including rates, expo, servo reversals, etc.

With multirotors, you're essentially using your TX to issue a command, and the flight controller software will try to do what you want it to do, with full control over all the motors, servos, etc.

 

[LitterBug]

Excellent news to hear you have it all sorted out! :applause:

Cheers!
LitterBug

 

[JamesWhom]

I'm glad to hear you've sorted out your tricopter! Yeah, what a lot of people forget with these things is that they aren't the same as fixed wing craft with more elementary electronics. You actually have a flight computer onboard and it's trying to stabilize flight for you. One needs to test the input commands result in behavior that you'd expect and also test that external influences/un-commanded forces on the airframe results in the opposite to counter the external forces.

Similarly, I think a lot of people who come from fixed wing or even heli RC, thinks they can just program their TX, taking advantage of expo, curves, etc, and think their computer driven controllers allow, forgetting that this actually works against them for better flight characteristics. All the programming and configuration should be on the flight controller for multirotors, including rates, expo, servo reversals, etc.

With multirotors, you're essentially using your TX to issue a command, and the flight controller software will try to do what you want it to do, with full control over all the motors, servos, etc.

Thank you to you both

Coming from a fixed wing background, I completely understand your point about assumptions over how the electronics work. It's been a learning curve, but I have learned much through these issues and through the trial and error in attempting to overcome them. I'm sure there will be more before this project is at an end and I possess a perfectly flying AP platform

 

[JamesWhom]

Update: Whilst I try and work out how to upload pictures to Flitetest on my new windows machine or ipad (my Mac is out of action), I have a few updates.

I've been enjoying having a working Tricopter to experiment with. Apart from cracking a boom, all is good. P and I settings have been set to levels I quite like, and I am getting a lot of information from Youtube and other threads about setups.

However I have another issue that I cannot find the solution to.

Problem 5) The copter stick inputs seem to continually add power to one motor or the other if held in one position. For example, if I have the copter on a table, props off, plugged in, no throttle input, and push the left stick over to the right, the right hand motor will eventually start to spin up. Even if it doesn't reach the point where it will start to spin up, say I leave the stick over to the right for a few seconds, and I apply throttle, the motors will spin at uneven speeds, the right one spinning more. This seems problematic for flight.

Is this supposed to happen? If it is not, then what modes to I need to program to fix it?

Cheers.

 

[LitterBug]

That may very well be normal behavior with the props off. The FC is trying to honor your stick command, but since the props aren't there, the frame is not moving in the direction the FC told it to. So the FC keeps feeding in more power hoping that it will get a reaction. Does it respond correctly in the air with props on?

Cheers!
LitterBug

 

[JamesWhom]

That may very well be normal behavior with the props off. The FC is trying to honor your stick command, but since the props aren't there, the frame is not moving in the direction the FC told it to. So the FC keeps feeding in more power hoping that it will get a reaction. Does it respond correctly in the air with props on?

Cheers!
LitterBug

Okay, that makes sense. The thing is it does this with props on too. It also, when sitting on the ground without moving, without and stick commands whatsoever, starts to spin up the left hand motor. What do you think this may be? :/

Cheers for your help!

James.

 

[LitterBug]

If it is not in the air, and the frame is not reacting the way the FC thinks it should, it will adjust the motors until it gets the response it is looking for. If you have the props off, arm it, pick it up, and move it around on the three axis. You will see the FC changing the motors and servo reacting to the motion to compensate for the actions the frame is making. What flight mode are you in? Have you calibrated the sensors and level? Is the frame level or tilted?

Cheers!
LitterBug

 

[JamesWhom]

It is doing what you say, but extremely slowly on the ground, which seems odd. The tail servo clearly adjusts when I pick it up, and when the motors are running, I can see and hear all of them reacting. I guess you are right

The flight mode is not auto level, if that is what you mean. I calibrated the sensors whilst the copter was sat on the ground where I was performing the experiment. This meant that the copter thought it was level.

Hmm, I'll have a play around with some settings and see if anything changes.

thanks for your help,
James

 

[makattack]

Don't forget that the version of the software you installed is known to be buggy, so certain unexplained behavior like that may well indeed be a "feature" -- although, I can't seem to find a comprehensive bug list.

 

[The-One-Who-Never-Crashes]

Thanks again for your help. I have done as you said and increased the percentages to 125%, yet the kk2 is saying that the travel is still only +40 max. It has increased the end point, but not enough.

Have you flown the copter?

 

[JamesWhom]

Yes I have now thank you

 

[JamesWhom]

So I'm thinking of upgrading my Electrohub frame to a more robust and portable carbon frame such as the Hobbyking Titus 600. What do you guys think? Anyone with knowledge about the FT electronics package motors and esc's, do you think that this frame would cope with my current electrical setup?

My original plan was to use the Electrohub frame and build my own landing legs and camera rails etc from wood. However, unfortunately I am currently away at college and using woodworking tools, drills, saws, is pretty inconvenient. A bolt together solution seems a little more practical.

 

[JamesWhom]

 

[makattack]

Personally, if I were going to go with a high end AP tricopter setup, I would go with a RCExplorer kit. It's more than half the weight, and with much higher quality parts and electronics options that are well proven. Sure, it may cost more, but I suspect in the long run, it'll equalize or even cost less and will result in a much higher quality tricopter.

 

[JamesWhom]

Hmmm, true, but I do like the idea of having big landing legs and plenty of space to swing a gimbal. Having said that, I would like to support David Windestal's products more than Hobbyking's.

 

[The-One-Who-Never-Crashes]

Hmmm, true, but I do like the idea of having big landing legs and plenty of space to swing a gimbal. Having said that, I would like to support David Windestal's products more than Hobbyking's.

I second getting RCExplorer's kit. The latest version of the Tricopter (v4) flies really well. If you want to use a gimbal on it, you can attach it to the front spacer, like this: https://www.google.com/search?q=rce...=P4HxV8u8L5ecjwPR-b2IDg#imgrc=RFvDK7fIhC21lM:

Have fun!