Author open-sources ~$20 dual-encoder closed-loop stepper driver that compensates for gearbox backlash in software

A developer designed an open-source closed-loop stepper driver for their 3D-printed robotic arm. It uses dual encoders to separately measure motor position and the actual joint position after the reducer, compensating for backlash in software rather than relying on a high-precision reducer. The driver is based on the ESP32-S3 and TMC2209, and the author aims to keep the cost at about $20. The code is already on GitHub. The author also asks whether anyone has made similar attempts and how to handle backlash compensation without destabilizing the control loop.