Here er,start,i and er,end,i are angular errors in degrees against the target at the two ends of observed interval i, within its constant-action segment; wi=1/FPS. ATEr is the trapezoidal time integral divided by total observed duration, a time-weighted mean error rather than an unnormalized integral. No arc-length resampling is used. The default minimum rotation normalizer is θmin=10 degrees. θobs is the observed total rotation. nmismatch counts intervals whose commanded and observed rotation-activity states disagree; nactive counts intervals with commanded or observed rotation.
Observed rotation activity means angular speed exceeds rotation_speed_threshold=6.0 degrees/second by default. Commanded but stalled rotation and uncommanded rotation contribute to activity error; observation gaps are missing data, not freezes.
Lower raw error is better. If rotation is neither commanded nor observed, the metric is not_applicable, not a perfect score. Target angular amplitude is prediction-derived (amplitude_calibrated=false); this does not establish accurate execution of an independently specified angle. Backend: pose_action; official metric.