Many motors and ESCs have a dead zone. This is the zone between the zero throttle value and the throttle value at which the motor starts to move. This can be compensated by setting minimum throttle in the firmware.
this is for motor!!!
but i find [SERVO1_FUNCTION]= 26 (GroundSteering)
it have dead zone too .but seems have any choise to fix this?
How big is the dead zone? The autopilot will almost never attempt extremely low angle turns, so a few degrees dead zone does not matter much. Also, what servo are you using? Perhaps you need to get a more powerful one.
I don’t think autopilot outputs have a deadzone, but the inputs can be configured with one (RCx_DZ). Set that parameter to a small or zero value if you don’t like the behavior.