// the find
peng-zhihui/Dummy-Robot
我的超迷你机械臂机器人项目。
The open-source hardware and firmware for peng-zhihui's viral 6-DOF desktop robotic arm — Altium PCB designs, a custom CAN-bus closed-loop stepper driver, and STM32F4/FreeRTOS firmware with DH-parameter kinematics. It's for makers who want to build a real (if expensive) arm from scratch, not a software framework to build on top of an existing one.
The stepper driver firmware is a genuine rewrite in C++11, hardware-decoupled from the STM32 HAL so it could realistically be ported to another MCU, with CAN and UART protocol templates and flash-emulated EEPROM for persistent params. The zero-point calibration trick — low-torque drive into a mechanical limit for coarse zero, then single-turn absolute encoder for fine zero — avoids needing dual encoders or a battery-backed absolute encoder, which is a real cost/complexity win. Inverse kinematics picks among the ~8 solutions by minimizing total joint travel from the previous pose, and the three command modes (SEQ/INT/TRJ) map cleanly to different use cases (pick-and-place vs. real-time vs. toolpath-following).
PCB sources are Altium (.PcbDoc/.SchDoc) — no gerbers-only fallback for most boards, so anyone without a paid Altium license can't inspect or modify the schematics, only order the boards as-is. Dynamics/torque control is explicitly unfinished, and the PC-side control software (Unity3D-based) is not open sourced at all, so a chunk of the actual operating stack is missing from the repo. Documentation is almost entirely Chinese with no maintained English translation beyond a video link, which is a real barrier given the BOM-heavy, multi-board build this requires. No commits since March 2024, and the promised cheaper '青春版' (3D-printed, no harmonic drive) never landed here — so what's public is still the expensive original with a ~600 RMB secondhand harmonic reducer per joint.