feat(uavcan): support for new Continious, Periodic and Cell Battery messages by Claudio-Chies · Pull Request #27464 · PX4/PX4-Autopilot

Claudio-Chies · 2026-05-26T11:21:51Z

Summary

Add UAVCAN bridge support for the multi-message smart-battery protocol (BatteryContinuous / BatteryPeriodic / BatteryCells) and a host-runnable gtest harness that exercises the UAVCAN→uORB path end-to-end through libuavcan's loopback transport.

Problem

PX4's UAVCAN battery bridge only understood the legacy BatteryInfo/BatteryInfoAux and CBAT messages. Newer style smart batteries split their data across a BatteryContinuous (high-rate) + BatteryPeriodic (low-rate) + BatteryCells trio, which the bridge ignored. Separately, the bridge had no automated test
coverage at all: verifying a change meant wiring real hardware on a CAN bus and watching listener battery_status. The driver is also gated on PLATFORM_NUTTX, so it isn't compiled in the px4_sitl_test build that make tests uses, leaving no path to test it in CI.

Solution

Add a BatteryDataType::Multi mode that claims a node on the first multi-message frame and suppresses the legacy BatteryInfo/BatteryInfoAux/CBAT handlers for that node to avoid double-publishing.

BatteryContinuous
maps voltage/current/SoC/temperature/fault flags and charging state;
BatteryPeriodic
maps cell count,
nominal voltage, capacity (with full_charge_capacity→design_capacity→BAT${i}_CAPACITY param fallback), cycle count, SoH and serial number into battery_info;
BatteryCells
fills per-cell voltages and max_cell_voltage_delta. The delta computation is extracted into a reusable static

For testing, a BUILD_TESTING-gated standalone CMake target (src/drivers/uavcan/sensors/test/) compiles libuavcan core + DSDL + the bridge sources without CONFIG_DRIVERS_UAVCAN, so the bridge links into a functional gtest. A generic UavcanBridgeTestFixture spins N loopback-paired libuavcan nodes — index 0 hosts the
bridge, the rest publish synthetic frames — and is reusable for other UAVCAN sensor bridges. BatteryBridgeTest covers field mapping, battery_info serial-number/id propagation, multi-instance separation, capacity param fallback, and edge cases (zero nominal voltage → NaN, missing capacity, UINT*_MAX "not provided"
sentinels, charging/fault flag handling). Runs under the existing make tests / checks.yml job — no new CI workflow.

Related PR

Better Battery Messages dronecan/DSDL#7

dakejahl

Can you add some instructions to your CLAUDE.md for prettier PR descriptions?

This is what I use, maybe we should add this to the PX4 project CLAUDE.md

CLAUDE.md

github-actions · 2026-05-27T06:50:58Z

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Updated: 2026-06-02T09:25:06

…oltage delta

hamishwillee

Note that MAVLink follows the same model - BATTERY_INFO is the slow message, BATTERY_STATUS_V2 is the fast message - planned to go in very soon #25347

The battery RFC stripped out the cell information message from BATTERY_STATUS when inventing BATTERY_STATUS_V2 as "diagnostic" - there's a proposal that it be retained in a separate message, but no one has defined its form.

EDIT, I guess my point is that it is worth looking at the form of the messages because BATTERY_STATUS_V2 can still change, and if there are significant differences we should look at them now.

…tinuous, periodic, and cell data

Claudio-Chies · 2026-05-27T07:15:36Z

@dakejahl i've also added CI tests for the can battery driver. open for discussion if this adds too much clutter, which i guess it might be the case.

dakejahl

If we're going to add tests shouldn't they cover the callbacks? Maybe not necessary or that useful for this module though 🤷

Claudio-Chies · 2026-05-28T07:59:55Z

@dakejahl which callbacks do you mean? i am testing the callbacks of the three messages which i'm implementing by comparing against the uorb messages.

…ellVoltageDelta function

Claudio-Chies requested a review from dakejahl May 26, 2026 11:22

dakejahl reviewed May 26, 2026

View reviewed changes

feat(battery): add computeMaxCellVoltageDelta function to calculate v…

dc0a6a6

…oltage delta

Claudio-Chies force-pushed the pr-uavcan_battery branch from b261478 to 7011dd1 Compare May 27, 2026 07:00

hamishwillee reviewed May 27, 2026

View reviewed changes

Claudio Chies added 2 commits May 27, 2026 09:04

feat(battery): add support for multi-message smart batteries with con…

28ac2ff

…tinuous, periodic, and cell data

feat(tests): add UAVCAN battery bridge tests and CMake configuration

ff9cb4a

Claudio-Chies force-pushed the pr-uavcan_battery branch from 7011dd1 to ff9cb4a Compare May 27, 2026 07:09

dakejahl reviewed May 27, 2026

View reviewed changes

Claudio-Chies marked this pull request as ready for review June 1, 2026 07:10

feat(battery): add fault flag bitmask helpers and improve computeMaxC…

c41f3d9

…ellVoltageDelta function

Claudio-Chies requested review from alexcekay and dakejahl June 4, 2026 13:16

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feat(uavcan): support for new Continious, Periodic and Cell Battery messages - #27464

feat(uavcan): support for new Continious, Periodic and Cell Battery messages#27464
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