Isaac Barham
79a4caa1f6
Retain the absolute desired-curvature base and unchanged C0, while adding measured yaw-error correction to C1 under fresh PSCM status. Preserve command limits, reset on override or unusable status, and release stored correction with the base request. Admit reachable partial increments at host slew limits. Publish PSCM enums with original CAN receipt timestamps through carStateSP. Add telemetry, status/driver guards, CAN roundtrip tests and recorded fixtures. Validation: focused suite 116 tests and 38 subtests; Ruff, settings compilation and diff checks pass. Production replay covers 52,273 route80 cycles; no-status fallback preserves v4 over 246,961 cycles / 43 segments. Physical stability and the reported 85-degree plateau remain unvalidated; EPS limits can inhibit the new correction.
What is cereal?
cereal is the messaging system for openpilot. It uses msgq as a pub/sub backend, and Cap'n proto for serialization of the structs.
Messaging Spec
You'll find the message types in log.capnp. It uses Cap'n proto and defines one struct called Event.
All Events have a logMonoTime and a valid. Then a big union defines the packet type.
Best Practices
- All fields must describe quantities in SI units, unless otherwise specified in the field name.
- In the context of the message they are in, field names should be completely unambiguous.
- All values should be easy to plot and be human-readable with minimal parsing.
Maintaining backwards-compatibility
When making changes to the messaging spec you want to maintain backwards-compatibility, such that old logs can be parsed with a new version of cereal. Adding structs and adding members to structs is generally safe, most other things are not. Read more details here.
Custom forks
Forks of openpilot might want to add things to the messaging spec, however this could conflict with future changes made in mainline openpilot's cereal spec. Rebasing against mainline openpilot then means breaking backwards-compatibility with all old logs of your fork. So we added reserved events in custom.capnp that we will leave empty in mainline openpilot's cereal spec. If you only modify those, you can ensure your fork will remain backwards-compatible with all versions of mainline openpilot and your fork.
An example of compatible changes:
diff --git a/openpilot/cereal/custom.capnp b/openpilot/cereal/custom.capnp
index 3348e859e..3365c7b98 100644
--- a/openpilot/cereal/custom.capnp
+++ b/openpilot/cereal/custom.capnp
@@ -10,7 +10,11 @@ $Cxx.namespace("cereal");
# DO rename the structs
# DON'T change the identifier (e.g. @0x81c2f05a394cf4af)
-struct CustomReserved0 @0x81c2f05a394cf4af {
+struct SteeringInfo @0x81c2f05a394cf4af {
+ active @0 :Bool;
+ steeringAngleDeg @1 :Float32;
+ steeringRateDeg @2 :Float32;
+ steeringAccelDeg @3 :Float32;
}
struct CustomReserved1 @0xaedffd8f31e7b55d {
diff --git a/openpilot/cereal/log.capnp b/openpilot/cereal/log.capnp
index 1209f3fd9..b189f58b6 100644
--- a/openpilot/cereal/log.capnp
+++ b/openpilot/cereal/log.capnp
@@ -2558,14 +2558,14 @@ struct Event {
# DO change the name of the field
# DON'T change anything after the "@"
- customReservedRawData0 @124 :Data;
+ rawCanData @124 :Data;
customReservedRawData1 @125 :Data;
customReservedRawData2 @126 :Data;
# DO change the name of the field and struct
# DON'T change the ID (e.g. @107)
# DON'T change which struct it points to
- customReserved0 @107 :Custom.CustomReserved0;
+ steeringInfo @107 :Custom.SteeringInfo;
customReserved1 @108 :Custom.CustomReserved1;
customReserved2 @109 :Custom.CustomReserved2;
customReserved3 @110 :Custom.CustomReserved3;
Example
import openpilot.cereal.messaging as messaging
# in subscriber
sm = messaging.SubMaster(['sensorEvents'])
while 1:
sm.update()
print(sm['sensorEvents'])
# in publisher
pm = messaging.PubMaster(['sensorEvents'])
dat = messaging.new_message('sensorEvents', size=1)
dat.sensorEvents[0] = {"gyro": {"v": [0.1, -0.1, 0.1]}}
pm.send('sensorEvents', dat)