peg_wrench_to_pad_loads — DRIVE pegtactile op

• Data kinds: signal × signal × table → table

• Call: import fullseye as fs; fs.ledger.peg_wrench_to_pad_loads(F_pad, M_pad, pad: 'dict') -> 'dict' (to call the implementation directly, import pegtactile; pegtactile.peg_wrench_to_pad_loads(F_pad, M_pad, pad: 'dict') -> 'dict'; from the registry, opsdrive.get("peg_wrench_to_pad_loads"))

Usage

Wrench that the 2 pads apply to the peg (gripper frame, about the grasp point) → for each pad (normal force P, shear on the membrane q = (q_u, q_v)).

Equilibrium (derivation): pad R (+x) applies −N_R x̂ and T_R to the peg, L (−x) applies +N_L x̂ and T_L. F_x = N_L − N_R, F_y = T_Ry + T_Ly, F_z = T_Rz + T_Lz, M_y = −w(T_Rz − T_Lz), M_z = w(T_Ry − T_Ly), M_x = torsion (half each). The normal is N = G₀ ∓ F_x/2 from the grip force.

Returns: R/L (each with P, q (received by the membrane = −T), slip_ratio = |q|/(μP), torsion (torsion received by the membrane), torsion_ratio = |torsion| / full-slip torque (3π/16)μPa), torsion (half of the torsion on the peg, M_x/2), ok (both |q| < μP), min_margin, torsion_ok. Slip (|q| ≥ μP) and full slip in torsion are returned as flags (not exceptions: the synthesis is a model of proportional loading and no-slip torsion). Raises ValueError: shape is not (3,) or not finite; the normal force of either pad is 0 or less (the pad separates = outside this mapping. fail-closed).

References (sample data, literature)

• 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.

Runnable examples (verified samples that actually call this op)

• poc_knife_tactile_toughness — py -3.11 examples/poc_knife_tactile_toughness.py

• poc_peg_insertion_tactile — py -3.11 examples/poc_peg_insertion_tactile.py

Ops the type connects to (they accept table as input)

course_layout · course_occupancy · course_contains · world_build · world_camera · world_move · lidar_scan · rss_longitudinal_same

Same category (pegtactile)

pad_params · pad_context · pad_loads_to_peg_wrench · pad_shear_asymmetry · pad_marker_displacement · pad_tactile_frame · pad_tactile_read · contact_candidates

*Provenance: pegtactile.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.