K. Isom
c27d91c857
uv-managed Python app for ramping Crazyflie 2.1 / Bolt motors on a
thrust test stand over a Crazyradio.
- cf_link.py: thread-safe cflib wrapper — scan/connect, supervisor
arming (send_arming_request) with legacy forceArm fallback, motor
override via motorPowerSet params, battery + estimator-state logging,
firmware-console capture, and a log buffer for the UI console.
- app.py: DearPyGui UI with a per-frame ramp loop.
* Linked / individual motor control, sliders + numeric entry (percent)
* Max-throttle limit, ramp rate, EMERGENCY STOP (button + SPACE)
* ARM button: disabled when disconnected, green when ready, yellow
when armed
* Telemetry: estimator-state panel (pose/yaw/flow), throttle + battery
plots that start at zero and only scroll while armed (freeze on disarm)
* Live console panel (app + cflib + firmware messages)
Benign cflib warnings (stale log blocks, missing optional params) are
filtered; safety teardown disarms on disconnect/quit.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
95 lines
4.0 KiB
Markdown
95 lines
4.0 KiB
Markdown
# test-stand
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A small GUI for ramping **Crazyflie** motors on a thrust/verification test
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stand. Connect to a Crazyflie 2.1 (`cf21`) or Bolt (`cfbl`) over a Crazyradio,
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arm the motor override, and ramp motors **individually or all together** with a
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configurable rate and a hard max-throttle limit.
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Built with **[cflib]** (the official Crazyflie Python library) for comms and
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**[DearPyGui]** (a Dear ImGui–based UI) for the front-end.
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> **Why Python and not C++?** There is no official, full-featured C++ Crazyflie
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> API. Bitcraze's only official C++ component is `crazyflie-link-cpp` (the radio
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> link layer, which ships *Python* bindings). The complete param/logging API
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> needed for motor control is Python-first via `cflib`; the C++ alternatives are
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> third-party and lag firmware. DearPyGui keeps the imgui feel while letting the
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> comms stay on the supported path.
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## How motor control works
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The firmware exposes a motor-override param group used for exactly this kind of
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bench testing:
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| Param | Meaning |
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| ---------------------- | ---------------------------------------------------- |
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| `motorPowerSet.enable` | `0` off · `1` per-motor (m1–m4) · `2` all follow m1 |
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| `motorPowerSet.m1..m4` | raw PWM `0–65535` |
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| `system.forceArm = 1` | keeps motors armed while stationary (recent fw) |
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| `motor.batCompensation = 0` | PWM maps directly to output (repeatable tests) |
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"Linked" mode uses `enable = 2`; "Individual" mode uses `enable = 1`. Missing
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params on older firmware are reported in the UI and otherwise skipped.
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## Setup
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Managed with [uv]. Requires Python 3.10+ and a Crazyradio (PA) dongle.
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```bash
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# from the repo root — creates .venv and installs deps from pyproject.toml
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uv sync
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```
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On Linux, allow non-root USB access to the radio (one-time) if you get
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permission errors — see Bitcraze's [USB permissions guide][udev].
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> No uv? Install with `pip install -r requirements.txt` into a virtualenv and
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> run `python main.py` instead.
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## Run
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```bash
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uv run test-stand # or: uv run main.py
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```
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1. **Scan** → pick the URI (e.g. `radio://0/80/2M/E7E7E7E7E7`) → **Connect**.
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2. Set a sensible **Max throttle limit** and **Ramp rate** first.
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3. **ARM**.
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4. Move the **Master** slider (Linked) or per-motor **M1–M4** sliders
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(Individual). Output ramps smoothly toward the slider target; live throttle
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and battery are plotted.
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## Safety
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- Motors never move until you press **ARM**, and throttle starts at 0.
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- The **max-throttle limit** clamps every target.
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- **EMERGENCY STOP** (button or the **SPACE** key) cuts all motors instantly.
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- Disconnecting, losing the link, or quitting the app disarms automatically.
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- Always secure the drone/motors to the stand before arming.
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## Troubleshooting
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- **`Unable to find variable [system.forceArm]` / `[motor.batCompensation]`** —
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harmless. These legacy params don't exist on current firmware; the app arms
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through the supervisor (a platform arming request) instead and sets those
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params only if present. The motors are driven by `motorPowerSet.*`, which is
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what matters. (The app no longer emits this line, but older builds did.)
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- **`Error no LogEntry to handle id=N`** — a benign cflib warning: the firmware
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is streaming a *stale log block* left over from a previous run that didn't
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disconnect cleanly, or from another client (e.g. cfclient) connected to the
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same Crazyflie. It doesn't affect motor control. The app filters this line,
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but to clear it at the source: close any other client and **power-cycle the
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Crazyflie**.
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## Layout
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```
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main.py entry point
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test_stand/cf_link.py cflib wrapper: connect, arm, motor PWM, telemetry
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test_stand/app.py DearPyGui UI + per-frame ramp loop
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```
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[uv]: https://docs.astral.sh/uv/
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[cflib]: https://github.com/bitcraze/crazyflie-lib-python
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[DearPyGui]: https://github.com/hoffstadt/DearPyGui
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[udev]: https://www.bitcraze.io/documentation/repository/crazyflie-lib-python/master/installation/usb_permissions/
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