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AffineDrift - scientific notes on golf mechanics, modeling, and control

AffineDrift

Scientific Notes on Golf Mechanics, Modeling, and Control

AffineDrift is a public technical notebook on golf-swing mechanics, multibody dynamics, and nonlinear control. It collects textbook-style chapters, source maps, links to model and code sources, validation notes, and critique responses. Publication here means that material is available to inspect; it does not by itself mean that a claim has been experimentally validated or peer reviewed.

Start with The Physics of Golf → Browse all articles

Publication-state key. Available means a page or program can be opened; Validated is reserved for a claim that names its evidence and validation boundary; Experimental marks in-development analysis or software; Planned is not yet delivered; Deprecated is retained only for compatibility or history; and Opinion identifies editorial interpretation. A page can contain more than one state, so follow its own evidence and limitation notes.

The Core Framework

Several pages model the golf swing as a control-affine system:

$$\dot{x} = f(x) + g(x)u$$

Where f(x) represents the drift dynamics (passive forces including gravity and velocity-dependent inertial coupling terms) and g(x)u represents the controlled torque inputs from the golfer.

Provenance. The control-affine form ẋ = f(x) + g(x)u is standard in nonlinear control theory (Isidori, 1995; Nijmeijer & van der Schaft, 1990). Its application to golf biomechanics — the drift/input decomposition, ZTCF, and DCR — is AffineDrift synthesis. See Theory Part 1 for the derivation and Critiques & Responses for scope limitations.

Latest Writing

• The Physics of Golf

  Available. Textbook treatment of golf kinematics, dynamics, and control; chapter-level claims retain their own evidence and review status.

• The Geometry of Motion

  Available. Differential geometry, Lie groups, and rigid-body motion, with chapter-level scope and review state.

• Proximal-to-Distal Energy Transfer in the Golf Swing

  Available computational publication. Technical monograph and computational publication with model-conditioned mechanisms, counterfactual tests, exact evidence links, and declared falsifiers. Independent scientific review and human validation remain open.

• Theory, Part 1 — Control-Affine Derivation

  Available. A model-conditioned control-affine derivation; it is not a validation of human intent or muscle action.

• Tangent-Space Series

  Experimental. Tangent-space arguments and local-control methods whose finite-time extensions require separate validation.

• The Drifter Manifesto

  Opinion and experimental program. Editorial positioning and hypotheses, with links to the technical sources that must carry the evidence.

• Critiques & Responses

  Available. Governed critique records; open status means unresolved, not disproved or resolved.

Books

• The Physics of Golf
• The Geometry of Motion
• Proximal-to-Distal Energy Transfer in the Golf Swing
• Book series — all volumes

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