commaai
Draft - Honda: fix 2025 Civic Hybrid braking
Draft PR for fixing 2025 Civic Hybrid braking. The 2025 Honda Civic is the first VOACC/radarless hybrid model, and is observed to max out at -0.5m/s2 when openpilot commands braking, ignoring requests up to -3.5m/s2. Stock VOACC has been observed to easily surpass -3.5m/s2 brake strength.
Hypothesis: I believe that radarless hybrids require a lead car to engage full braking, otherwise they coast slower to save fuel.
Reasons:
- After extensively searching cabana, I could not find a signal that was present in Stock ACC, that was missing from comma ACC, with the exception of the lead car data from the VOACC camera.
- In instances where the VOACC camera detects a lead car (eg: Honda saw the lead slow to a stop), it brakes at full -3.5m/s2 as commanded by comma. When VOACC doesn't see a lead it limits at about -0.5m/s2.
This is an early draft of code attempting to achieve the full -3.5m/s2, by spoofing a lead car from the VOACC camera when either: VOACC cannot see a car (Honda does not see stopped cars), or if experimental wants to stop for a red light in absence of a lead car.
Todo: test if this works
What does this fix exactly?
User in honda discord has logs showing that braking is maxing out at -0.5m/s2, ignoring requests up to -3.5m/s2.
Not sure this works, but the goal is to imitate a new brake channel that Honda stock ACC sends while braking on hybrids to see if it fixes it. Testdrive should be imminent.
The fix is similar to one I had do to for the MDX Hybrid PR.
(I set as draft PR because I like the CI code review stuff)
Revised approach to redefine a brake message, to align with how stock ACC does braking. Code was force-pushed to clean/new working PR.
Tests were successful. This is ready for review.