diabolo op• Data kinds: signal × signal × signal × scalar → table
• Call: import fullseye as fs; fs.ledger.string_tension_from_sag(p_left, p_right, p_diabolo, mass: 'float', *, accel=None, g: 'float' = 9.81) -> 'dict' (to call the implementation directly, import diabolo; diabolo.string_tension_from_sag(p_left, p_right, p_diabolo, mass: 'float', *, accel=None, g: 'float' = 9.81) -> 'dict'; from the registry, opsdrive.get("string_tension_from_sag"))
Computes the tension from the V shape of the string (the 2 stick tips and the axle position) (frictionless pulley = equal tension on both sides).
Least squares of T (û_L + û_R) = m (a − g⃗): T = m (a − g⃗)·n / |n|², n = û_L + û_R (û is the unit vector from the pivot → rod). At rest (accel = None) this equals T = m g / (sin α_L + sin α_R) (α = angle of the string from horizontal). The residual (violation of equilibrium) is also returned —— if large, it is an alarm for "forgot to supply acceleration / friction / elasticity". Raises ValueError: shape, mass ≤ 0, pivot coincides with the rod.
• Sample-data catalog (download URLs / licences) — 2-D uses skimage.data (BSD/public domain) plus synthetic images; 3-D lists download URLs for real data sources (Stanford, PDS, …).
• Operator provenance and references — the sources of the research/methods this op family came from.
• The canonical algorithm (author, year) and its uses are named in the family usage guide above.
• poc_diabolo_model_and_vision — py -3.11 examples/poc_diabolo_model_and_vision.py
table as input)course_layout · course_occupancy · course_contains · world_build · world_camera · world_move · lidar_scan · rss_longitudinal_same
diabolo)diabolo_params · diabolo_spheroid · spheroid_closest · diabolo_dynamics_step · diabolo_simulate · diabolo_state_sequence · diabolo_throw_catch_truth · string_tension_static
*Provenance: diabolo.py — DRIVE operator registry. This per-op note is generated by tools/opdocs.py md (do not hand-edit).*
© 2026 Kazufumi Furuse — Fullseye operator documentation. Licensed under Apache-2.0.