kendama op• Data kinds: none → table (an op determined by its arguments alone — it takes no image or data input)
• Call: import fullseye as fs; fs.ledger.kendama_params(preset: 'str' = 'jka_16_2', *, trick: 'str' = 'ozara', ball_radius: 'float' = None, mass: 'float' = 0.075, string: 'float' = 0.39, cup_radius_big: 'float' = None, cup_depth: 'float' = None, ken_length: 'float' = None, width: 'float' = None, rho: 'float' = 1.2, cd=0.4, cup_offset=None, tie_offset=None, cup_axis=None, g: 'float' = 9.81) -> 'dict' (to call the implementation directly, import kendama; kendama.kendama_params(preset: 'str' = 'jka_16_2', *, trick: 'str' = 'ozara', ball_radius: 'float' = None, mass: 'float' = 0.075, string: 'float' = 0.39, cup_radius_big: 'float' = None, cup_depth: 'float' = None, ken_length: 'float' = None, width: 'float' = None, rho: 'float' = 1.2, cd=0.4, cup_offset=None, tie_offset=None, cup_axis=None, g: 'float' = 9.81) -> 'dict'; from the registry, opsdrive.get("kendama_params"))
Kendama table. Default = preset="jka_16_2" (ball 60 mm, width 70 mm and overall length 180 mm are published values of the Japan Kendama Association (JKA); ken height 160 mm and cups 42 / 38 / 35 mm come from a user-provided description of the JKA 16-2 model (primary source not verified)). "recommended_large_cup" = big cup 49 mm, hole 24 mm.
> The detailed description below is the original text — the summary and the headings are translated.
鍵: ball_radius 0.030、string 0.39(糸 = 推奨 38〜40 cm)、pendulum_length = 糸 + 玉の半径(結び目 → 玉の中心、玉の糸穴は大きな穴の反対側と置く)、cup_radius_big / cup_radius_base / cup_radius_small(縁の半径)、cup_depth (大皿の深さ。既定 = 縁に乗った玉の下端の沈み r_b − √(r_b² − r_c²) + 1.5 mm = 玉が底に触れない深さ、と置く仮定)、ken_length(けんの高さ = けん先 → 中皿の縁、160 mm)、width(大皿の縁 〜 小皿の縁、70 mm)、hole_radius / hole_depth(玉の大きな穴。深さ = けん + 玉 − 全長 = 40 mm)、total_length(組み立ての全長 = けん + 玉 − 穴の深さ)、cross_radius / ken_radius / spike_length / cross_from_tip(仮定)、mass(玉、仮定 75 g)・ken_mass(仮定 70 g)。技 trick(KENDAMA_TRICKS: "ozara" 大皿 / "kozara" 小皿 / "chuzara" 中皿 / "ろうそく" = "rousoku")が姿勢を決める:
R_ken(けんの局所座標 → 世界: 局所はけん先 +x・大皿 +z・原点 = 皿胴の中心)、grip(持つ所、局所)、受ける皿 catch_cup("big" / "small" / "base")。そこから手元(= 持つ所)に対する cup_offset(受ける皿の縁の中心)、cup_axis (受ける皿の軸、世界)、tie_offset(皿胴の糸穴: 局所 (0, −cross_radius, 0))、top_offset(けん玉のいちばん高い所)、cup_radius(受ける皿の縁の半径)を出す。けんと皿胴は 1 つの剛体(姿勢は技ごとに固定、手元は並進)。cup_offset / tie_offset / cup_axis を渡すとその値で上書き(0 を渡すと点のけん = 支点 = 皿 = 手元: 定理の門)。catch_window = 0.003 m: kendama_simulate は玉の中心が「縁に乗る高さ h_c から 3 mm 以内」に下りてきた瞬間を捕球とする(玉が縁に触れた = 着地。縁から 1.5 r_b 上の窓に入っただけでは捕らない: 頂点が窓の中だと頂点で「捕れて」しまう —— 測って退けた)。rho/cd = 空気密度・抗力係数(rho = 0 で真空: 定理の門はこれで走らせる)。
fail-closed: 未知の preset、寸法 ≤ 0、皿の縁 ≥ 玉(縁で受けられない = けん玉ではない)、横幅 < 大皿の直径、糸 ≤ 玉の半径、穴の深さが (0, 玉の直径) の外、けん先の太さが穴に入らない、は ValueError。返り値には派生量 "cup_rest_height" = √(r_b² − r_c²)(受ける皿の縁に乗った玉の中心の高さ)、"bp"(ballistics.ball_params、中実球)。
• 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_kendama — py -3.11 examples/poc_kendama.py
table as input)course_layout · course_occupancy · course_contains · world_build · world_camera · world_move · lidar_scan · rss_longitudinal_same
kendama)elliptic_k_agm · pendulum_period_exact · pendulum_launch_speed · pendulum_rod_simulate · tether_tension_fixed · tether_slack_angle · swing_up_plan · swing_up_apex
*Provenance: kendama.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.