Stepper Stresser

Introduction

The stepper stresser script works with Klipper to determine the maximum acceleration and velocity of a stepper system.

See this video for an example application of this script.

The script pipes gcode to Klipper via the pseudo-serial port, commanding the x-axis to home, move and home again. At each stage, the GET_POSITION gcode is used to obtain the current position and MCU step count.

The acceleration (and velocity) of the moves progressively get faster, with the intention of inducing a failure.

The difference in MCU step counts after the first and second homing is then used to determine if the stepper has skipped sufficient steps to qualify as a failure.

Once a failure is detected, a binary search is performed to find the maximum "safe" acceleration and velocity values.

Setup

Ensure Klipper and your motion system is configured. At minimum, you need:

• x-axis with endstop at the 0 position
• Configured the acceleration and velocity limits greater than test intended test values

venv is recommended, but not necessary.

After setting up and activating venv, install the dependencies:

pip install -r requirements.txt

Usage

The main script accepts three optional arguments:

• --port_name: Path to Klipper's psudo-serial port (default: ~/printer_data_comms/klippy.serial)
• --max_travel: Maximum travel in mm (default: 300)
• --max_velocity: Maximum velocity in mm/s (default: 1000)

Examples:

python main.py # Run with default port name, 300mm max. travel, 1000mm/s max. velocity
python main.py --max_travel 50 --max_velocity 2000 # Run with default port name, 50mm max. travel, 2000mm/s max. velocity