Calibrating ESCs with Pixhawk Without rc trasmitter

Dear All,

I have been searching the internet for a way to calibrate my ESCs without an RC transmitter. I was able to find two solutions:
1- Use the software available in the pixhawk: mission planner --> terminal --> connect to px4 --> type setup --> esc_calib
2- Use a joystick to calibrate the escs
For the first solution, I tried calibrating my ESCs however they started beeping continuously. I checked the internet for the meaning of this and I found out that the throttle was not down even though I am not attaching any RC receiver to the pixhawk.

The second solution also did not work.

Any idea how can I achieve this? I know that it is recommended to use a radio transmitter however this option now is out of question since I am trying to make my copter autonomous.

Thank you