SR-Support Self-Righting Robot Tutorial
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SR-Support is a low-cost active self-righting device based on a 2-DOF arm. After tipping in any direction it plants its two-joint arm on the ground, rolls and levers itself back upright. This tutorial is organized as a reading order covering the full path from scratch to a verified build.
Reading order
| # | Page | Content | Note |
|---|---|---|---|
| 01 | Basics | Working principle, specs, BOM | read first |
| 02 | Environment setup | Create/activate .venv, prebuilt firmware + flash tools (Flash Download Tool / esptool), computer-side tools and MuJoCo env, optional PlatformIO, serial port | do this first |
| 03 | Flash the main firmware | Prebuilt bin (recommended for customers) or a PlatformIO source build, serial commands, boot behavior | skippable for stock units |
| 04 | Assembly: print, build, wire | Printed parts, horn index, wiring table, IMU mounting | skippable for stock units |
| 05 | Zero-calibration | Arrow-key jog + z zeroing (after re-indexing/re-assembly) | required for DIY builds; skippable for stock units |
| 06 | Debug and calibration | Whole-robot check and calibration: telemetry, IMU, servos, center check, four lying poses, fall gate | |
| 07 | Self-righting usage and monitoring | Four fall directions, expected motion, monitoring and logs | |
| 08 | WiFi and the simulation twin | Status page, home-WiFi provisioning, wireless MuJoCo twin | optional |
| 09 | Troubleshooting | Common symptoms and fixes | reference |
| 10 | Reference: model, parameters, licensing | Model files (XML/STL), parameters, reference sequences, licensing | reference |
Factory state of a finished unit (two reading paths)
This tutorial serves two audiences - pick the path that matches yours:
| Reader | Factory state | Recommended path |
|---|---|---|
| Finished-unit user | Assembled and wired, firmware flashed, calibrated (servo zeros and IMU accel zeros baked), tested (all four get-up directions verified per unit) | Go straight to 07 usage and 08 WiFi/twin (optional); keep 09/10 for reference. Pages 02/03/04/05/06 are only needed for firmware upgrades, servo/IMU replacement or horn re-mounting; to use the twin/telemetry tools on page 08, first install the computer-side tools from page 02. |
| Kit / DIY builder | Starts from parts | Follow 01 → 02 → 03 flash → 04 assembly → 05 zeroing (required) → 06 debug/calibration → 07 end to end. Both zeroing (05) and calibration (06) happen after full assembly and flashing: z does not use the IMU and works in any pose; c needs the assembled robot standing level. |
Recommended first-use check for a finished unit: power up upright → confirm
up≈(0,0,1)→ tip it once in each of the four directions per page 07 and confirm it stands up.
Prerequisites
- SR-Support mechanical parts (bottom plate, shoulder servo mount, elbow servo mount, top strut; printing and assembly on page 04);
- ESP32-S3 board, Juxi ICM42670P IMU, passive direct-drive servo adapter board;
- 2× PTK7452MG (180° PWM) servos;
- A servo power supply (5 V / ≥5 A) and a USB-C data cable;
- A computer with the environment from page 02.
Verified status (2026-11-06)
All four fallen directions have been verified on the real robot, each as a direct get-up (no roll-over needed), taking about 1–6 s; no servo envelope violations were recorded. The kit also ships an arrow-key zero calibration tool (page 05), a WiFi status page with home-network provisioning, and a wireless MuJoCo live twin (page 08).
Safety
- Hold the robot on first power-up, keep a 30 cm clear area, and send
xor cut servo power on any anomaly;- Never stall a servo longer than 1 s; stop when the case exceeds 60 °C;
- the servo supply 5 V / ≥5 A (verified for all four get-up directions);
- anything above 5 V goes to the servo rail only - never to the ESP32 5V/3V3;
- Everything shares one ground; power-up order is in page 04.