Poor Slow Speed Control

Hi there.

I have some experience with BLDC motors, but this is my first time with a ESC Mini FSESC4.20, connected to a sensorless BM400 V3 2845/09 2100KV - INRUNNER MOTOR. 

I have it connected to the VESC Tool software and I can read and write to the drive, no problem.

I my application (a type of eboard), I need a very slow (high torque) start to the motor, and the ability to ramp up slowly to a speed set by the user.

If I run the motor detection routine, I see exactly what I am looking for, namely a smooth, fairly high torque ramp up from zero to a few thousand RPM.

I am currently running with a PPM input, and I can apply ramps to the input.

The problem is that the motor starts very roughly, sometimes spinning backwards.

At some points in my testing I have achieved full PID control at high speeds, but not at low speed. A have tested with BLDC and FOC modes, as well as PID, Current and Duty cycle control modes.

My initial question is, is there any way of duplicating the ramp-up used in the motor detection test?

Any help would be appreciated.

David