I'm having a problem with a quadcopter that's running arducopter. It keeps tilting backwards.
I am 100% sure that the escs are connected to the correct apm outputs according to the setup diagram for my "x" configuration. I also calibrated them individually (the all at once method wouldn't work for anything). The receiver channels are also connected to the apm correctly. The propellers are all spinning in the correct direction (according to the setup diagram for my "x" configuration).
The apm unit is facing forward like its supposed to.
The compass, accelerometer and receiver are calibrated correctly. When sitting on a level surface, mission planner shows that the apm knows that it's level.
When I do the hand test, it seems to work except that it wants to tilt itself backwards. Yaw, pitch and roll do what they are expected to do except that pitch is inverted. By this I mean pulling back on the stick makes it tilt more forwards and puching forward makes it tilt more backwards.
If I push the stick to the right, it wants to bank right. If I push it to the left, it wants to bank left as it should.
It's just that if I give it throttle and don't touch the other stick, it will tilt backwards and do a backflip into the ground. In order to get it off the ground, I have to pull back on the stick a lot to get it to go up.
Once I finally got it into the air, it was really unstable to fly. It wasn't just a little off, it was all over the place and for the most part out of control. I got like 20 feet off the ground by accident, still holding the pitch back a lot. I decided to just cut the throttle and let it crash to the concrete before things got worse. Surprisingly, nothing broke.
I tried a second time. This time, once I got into the air, I let go of the right stick hoping that stabilize mode would do it's job.
NOPE.
It titled back and crashed into a tree with mind blowing speed.
This time a ton of stuff flew apart. The only thing that appears to be unfixable is the minumosd. It just has two red lights and doesn't do anything else.
I haven't been able to find the solution to this problem on the internet. The only thing I can find is about making sure the escs are plugged into the correct outputs (which they are).
Does anyone know how to make it fly the ways it's supposed to. Is there a way to fix that minumOSD chip with the two red light error code?
Replies
Have you balanced the props and motors?
Here is a screenshot of one of my data logs. Don't really know what to make of it. It looks like the DesPitch (meaning desired pitch?) is always higher than zero which means that it thinks it has to pitch in that direction all the time? Maybe I should try to trim it?
I'm pretty sure the props and motors aren't balanced. I haven't balanced them myself.
I tried moving stuff around to adjust the center of gravity and it doesn't matter which side I put the battery on, it still wants to tilt in the same direction. By grabbing the middle part of the frame with my hand it seems to have the center of gravity pretty centered but that's just a rough estimate.
I have also done absolutely no PID tuning. I'll try increasing my P values.
And yeah this is all in stabilize mode.
I'd invert the pitch output on your transmitter first so the controls are more intuitive.
It helps to have your centre of gravity as balanced as possible. You may want to try repositioning you battery and see if that helps.
What PID tuning have you done so far? am assuming you are trying to fly in Stabilise mode. Perhaps you need to increase the stabilise P values so that it puts more effort into staying level.
Have you got a dataflash log. Are you sure you are using the correct motor layout? Other flight controllers use different layouts.
Also, I just now noticed, from reading this webpage that in tip #3 it says to make sure the jumper is in place is powering the apm from a BEC. The apm is receiving it's power from my receiver sorta I guess. So I'll try putting in the jumper and see if it somehow magically makes all that difference.
The way I have is set up as is the front-right motor is connected to channel 1. The front-left motor is connected to channel 3. The back-left motor is connected to channel 2. The back-right motor is connected to channel 4.
It's set up according to this diagram. I'm using the quad-X configuration which is what my ardupilot unit is flashed with.
I'm in the process of downloading all my data logs. There are like 40 of them. Most of them are probably worthless but I just need the ones from any sessions where I actually got into the air, right?
What exactly am I looking for in these logs? Where/how is a good way to post them? I will post them later is the day tomorrow.