Some questions about my quad

ArduCopter Copter 4.3
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  1. Can uncalibrated ESC’s take away from radio TX resolution? Was flying the other day and it was extremely difficult for me to find a steady hover in stabilize mode. The tiniest amount of stick movement would make the quad either go up or down almost as if there were no in between or hover point.
  2. Is MOT_THST_EXPO a set in stone value for a given prop, or can I play around with this value?
  3. Is is ok to disable the IMU temp prearm check? BRD_HEAT_TEMP

Thanks!
~Zach

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1.That is typical of Stabilize mode, nothing to do with ESC calibration. Use Loiter mode, there are several parameters associated with Loiter that can be set to your liking.
2. Unless you have a thrust stand the suggested value works for most applications. There is some question about some T-Motor ESC’s related to perceived internal thrust linearization.
3. Why do that? Have your performed the IMU Temperature Calibration assuming your Flight Controller supports it? IMU Temp Comp

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Leonard Hall explained setting and testing MOT_THST_EXPO

  • set too high you can see instability at low throttle
  • set too low you can see instability at high throttle
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@dkemxr I was curious because I had thought my ESC’s calibrated correctly through MP. They didnt. So I calibrated them manually with a frsky receiver I had laying around. This actually worked since my motors now respond at the very bottom of the stick range. And not only that, when testing the motors at the bench they spin and “sound” much smoother whereas before the calibration they sounded like they were screeching when raising the throttle. It also feels like its using more of the throttle range.

As for the IMU temp, I had to wait and use a good 10-15 mins of battery power before flight to warm up the IMU. It was about 30-35° outside. Will the calibration solve this problem?

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I don’t have direct experience with a board heated IMU but on other IMU’s this has helped when there is a large temperature differential from arming thru flight. So, my thought was if you are going to set a lower BRD_HEAT_TARGET value it will better compensate for the higher range of temperature.

I let my craft soak in a freezer and then run the compensation.

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Does the board have to be powered by the battery or just the USB after taking it out of the freezer and running the calibration?

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That might depend on the Flight Controller whether that will make a difference. On small boards with BECS and an OSD chip heating things up you want the battery connected. Or if it’s a FC/ESC stack, you want the battery connected. If it will heat up the Flight Controller you want it connected.

Make sure once you start the procedure you don’t move it. And as per the Wiki if it has a board heater set it high for the test to get things cooking.

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Its the pixhawk cube black

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Did a temp calibration and I like to think I did it the right way. INS_TCAL_ACC and INS_TCAL_GYR now showing all custom calibrated values. So Im assuming this is correct.