Crazyflie big quad with px4flow

Dear all,
I install px4flow with crazyflie big quad. When I step into ‘position control’ mode, the quad always drifts severely to different directions at each time. Using other px4 hardwares, this problem does not show up and everything works just fine. I cannot figure out why only crazyflie has this problem. I am sure that the px4flow is correctly installed as other px4 hardware.

Have you verified PX4 actually connected to the px4flow? Check the console (if available on crazyflie) or the logs.

Thanks for the quick reply. I am sure the px4flow has communicated normally with CF big quad. I have observed the ‘quality’ and ‘distance’ data on QGC, both of which make pretty sense. The quality value is above 200 for most of the time, and sonar also responds quickly when I move it up and down. I also checked the installation direction of the flow module, which is also correct. But I want to mention that I do not use brushless motor with servos, instead, I use coreless motor. Does it have any impacts on position control?