Problem
wuji-mjlab logs Episode_Metrics/joint_acceleration_rms, but a downstream task consuming UniLab's public Entity API cannot obtain joint acceleration from the mjwarp backend. During wuji_unilab metric-name alignment, all other source metrics could be mapped without backend-private access.
Evidence
- The source metric reads
robot.data.joint_acc and computes RMS across selected joints.
- UniLab
EntityData exposes joint position and velocity but no joint acceleration.
- UniSim has no declared
qacc/joint-acceleration state field.
- A finite difference of public joint velocity would be a different, control-step quantity and must not be silently logged under the source native-acceleration name.
Requested maintainer decision
Choose whether to add a declared backend-neutral joint-acceleration state contract, expose an explicitly named control-step finite-difference metric at the task layer, or keep this source metric unsupported. The Wuji downstream currently chooses the last option and reports the omission.
Scope
This does not block Wuji training or the other metric-name alignments. Any new public backend contract requires owner design, tests, and adapter behavior before downstream consumption. No fallback is requested.
Related: unilabsim/wuji_unilab#17 and roadmap unilabsim/wuji_unilab#1.
Problem
wuji-mjlablogsEpisode_Metrics/joint_acceleration_rms, but a downstream task consuming UniLab's publicEntityAPI cannot obtain joint acceleration from the mjwarp backend. Duringwuji_unilabmetric-name alignment, all other source metrics could be mapped without backend-private access.Evidence
robot.data.joint_accand computes RMS across selected joints.EntityDataexposes joint position and velocity but no joint acceleration.qacc/joint-acceleration state field.Requested maintainer decision
Choose whether to add a declared backend-neutral joint-acceleration state contract, expose an explicitly named control-step finite-difference metric at the task layer, or keep this source metric unsupported. The Wuji downstream currently chooses the last option and reports the omission.
Scope
This does not block Wuji training or the other metric-name alignments. Any new public backend contract requires owner design, tests, and adapter behavior before downstream consumption. No fallback is requested.
Related: unilabsim/wuji_unilab#17 and roadmap unilabsim/wuji_unilab#1.