Mechanical record
The rotation record contains commanded and measured speed, angular position, direction, acceleration and stop duration. A three-axis accelerometer fixed at the plant module records vibration and transient acceleration. Each test reports mean speed, speed ripple, peak acceleration, RMS vibration and the difference between commanded and measured angle.
| Measurement | Method | Reported value |
|---|---|---|
| Angular speed | encoder count divided by elapsed time | mean, SD, minimum and maximum |
| Angular position | encoder index at each timestamp | position error and missed counts |
| Acceleration ramp | encoder and accelerometer time series | ramp duration and peak acceleration |
| Vibration | three-axis accelerometer at the plant module | axis-specific RMS and peak acceleration |
| Endurance | loaded continuous run | temperature, stalls, slip events and speed drift |
Plant exposure record
Mechanical measurements are synchronised with PPFD, air velocity and root-zone contact. One plant-position record therefore identifies the gravity direction in plant coordinates, incident light, immersion state and local air movement at the same time. This prevents a response caused by light or root-zone exposure from being assigned to rotation alone.
| Control group | Matched variables | Difference retained |
|---|---|---|
| Static control | crop, cultivar, age, mean PPFD, DLI and root-zone exposure | no periodic reorientation |
| Time-varying-light control | light sequence and root-zone exposure | static plant orientation |
| Matched-vibration control | measured vibration spectrum and cultivation conditions | no drum rotation |
| Rotating treatment | cultivation conditions and sampling schedule | periodic orientation cycle |
Plant response
Root-tip angle, shoot curvature and elongation are measured from indexed image sequences. Growth, root architecture and plant chemistry are analysed as separate endpoints. The experimental unit is one plant or one independent cultivation cycle; repeated frames from the same plant are not counted as independent biological replicates. Gravitropic interpretation follows the measured angle-time history and the known statolith–auxin response of roots and shoots.
Reporting
The report publishes the complete speed profile, acceleration trace, light and immersion records, sample count, biological replicate count and analysis code. Effect estimates are reported with confidence intervals. A rotation setting is identified by drum speed, direction, radius, ramp profile, operating duration and stop schedule rather than by a device preset name.