Moderator

Motors/ESC's very slow to respond, default PID's. Help!

I've set up my DIY quad with the default PID's (Roll_P 4.60, Pitch_P 4.60) and everything seems OK in tests except the motors/ESC's are very slow to react to tilting the quad while hand holding it. If tilted to the left 30 deg and then rapidly tilted to the right 30 deg it takes about 6 seconds for the 2 right motors (x-mode) to increase their rpm to the point that it can correct that movement!

Reactions to the roll and pitch stick movement are almost instantaneous like I'd expect but to the IMU movement it's incredibly slow.

Any ideas?

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Replies

  • Moderator

    Fixed! Don't power receiver before powering APM, contrary to what I've done my whole RC life!

    Hitec Aurora 9 Tx and Optima 6 Rx

  • Moderator

    Below is a graph of what's happening. The blue line shows a rapid tilt to 90 deg, the red line shows a gradual ramping of the output to the ESC taking nearly 8 seconds to reach 70 degrees. (I've isolated the APM from the frame completely to negate any vibration affects)

    Weird!! Any help or explanation would be appreciated, I've spent hours searching, reloading and rechecking.

    Could it be the on board sensor filters, I've tried desoldering the 3 little pads but even weirder things happen then

    3692339130?profile=original

  • Moderator

    Is there a way to test or see what signal goes to each ESC? Could it be the ESC's that are slow? They are the Turnigy TY-P1 25Amp HEXFET ESC's (link)

  • Moderator

    IMU test shows the values updating pretty quickly but the HSI (Horizontal Situation Indicator) in the mission planner is also slow to react to movements of the quad?

  • Moderator

    Adjusting Stablize_xx down and Rate_xx up doesn't seem to solve this. The large oscillations get progressively worse. The motors' response seems to lag behind the required response to stabilize the 'copter?

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