Wobble and Heat

ArduCopter Copter 3.6
1

WOBBLE AND HEAT ISSUE

I have built a hexacopter out of a cheapie hex thorax frame and spare bits but I have a few issues that I am trying to resolve. The build details are at the end and the link is a test flight log.

Issue 1. A pretty good wobble which does not abate and seems to be exacerbated by very slight amounts of wind. The Pixracer board is mounted on the frame using rubber 3M vibration mount screws.

Issue 2. Motors 1 and 2 (the middle left and right) get very hot. The test flight was barely a minute and they were just able to be touched. May this be due to the constant corrections required for the wobble. Other motors are warm but not significantly so. ESC’s also seem unaffected.

Issue 3. Float ?. A bit harder to explain. The craft maneuvers well and is responsive in pitch, yaw etc, however, throttle responsiveness when decreasing the altitude is slow. It’s like the props have so much lift that it takes a bit of time for the rotation speed of the motor to slow enough to allow it to lower the altitude. The effect is reduced when using 5x3 props as opposed to 5x45 BN props.

Pixracer R14

4S 5000mA Lipo

EMAX RS2205-2300 motors

ESC = TURNIGY MULTISTAR 40A BLHELI-S REV 16 ESC 2~4S V3 (OPTO).

ESC Settings as shown below

Startup Power = 0.5

Temp Protection = 140C

Low RPM Power Protection = yes

Brake on Stop = no

Demag Compensation = Low

Motor Timing = Medium

Other settings: MOT_PWM TYPE = Oneshot125

Weight = 1150gms

2

From looking at the log, its obvious the Roll PID is WAY off. I see a lot of over shoot, so I’m thinking the Roll P is too low.

I’d start off by using Inflight Tuning to get Roll settled down and then I’d run
AutoTune.

3

Thanks. Altered Roll and Pitch P from 0.135 (the default) to 0.09. Some very very minor twitching but good enough now to do an Autotune. Parameters changed were as follows:

ATC_RAT_RLL_P Default Setting = 0.135 to 0.09 (a bit more than half)
ATC_RAT_PIT_P Default Setting = 0.135 to 0.09.

They really need someone to make a plain english version of the parameter descriptions. Some are straightforward others are not.