Explore the Proximal–Distal Models

An Interactive Workbench for Forces, Moments, Transfer, and Counterfactuals

Run the open double-pendulum, triple-pendulum, and bilateral golf models in matched PyQt6 and React/Tauri interfaces.

1 Explore the Models

The interactive workbench turns the article’s diagrams into systems you can change and challenge. It includes double-pendulum, triple-pendulum, and bilateral golfer models, with force vectors, moment arrows, energy and power histories, torque counterfactuals, and parameter perturbations.

The workbench is maintained as an open-source resource in the Tools pendulum simulator. Its PyQt6 desktop interface and React/Tauri interface read the same experiment and glossary catalog. Definitions and scientific limits therefore have one source rather than two copies that can drift apart.

Before You Interpret a Plot

Every interactive run is labeled exploratory_model_output. It is generated by a declared mathematical model, not measured from a golfer. The article’s scripted analyses and recorded data remain the authority for published numerical results.

2 Choose a Guided Experiment

Open Companion Guide in either interface. Each experiment presents its hypothesis, observables, steps, interpretation tips, falsifier, and limitations before you change the model.

Guided Experiment	What to Vary	What to Inspect
Passive Transfer in a Two-Link Chain	Proximal drive and distal torque	Distal acceleration, interaction torque, power, and energy closure
Phase-Resolved Proximal Velocity	Analysis-window start and end	Drift/control grip work, Negative Grip Work, peak force, distal energy gain, and whether the conclusion changes across phase
Coordinate Force Sources	Torque history and wrist-drive onset	Full-trajectory Coriolis cross-speed, squared-speed/centripetal, gravity, damping, and applied-drive signed and absolute tangent impulse and generalized work
Distal-Torque Onset Comparison	Wrist-command onset	Late club speed, actuator work, and sensitivity to the timing grid
Three-Link Cascade	Segment geometry and timing	Whether the transfer pattern survives an intermediate segment
Two-Hand Force and Equivalent-Couple Mechanism	Hand separation and reaction directions	Net club moment, individual forces, and zero-moment-arm control
Pointwise and Forward Zero-Torque Counterfactuals	Intervention definition and cut time	Immediate decomposition versus the altered future trajectory
Parameter Robustness and Falsifiability Envelope	Geometry, inertia, damping, and timing	Whether a small plausible perturbation reverses the conclusion

Tooltips explain controls at the point of use. The searchable glossary defines terms such as interaction torque, equivalent couple, power, work, mass matrix, Jacobian, and ZTCF family without requiring the reader to leave the experiment.

3 A Known Limit of the Two-Link Model

The workbench now carries a Swing Objective Lab tile, which optimizes one downswing against five competing objectives under a shared torque budget. Its optima are dynamically feasible and not golf-like: they brake the arms to a standstill at impact, arriving with hands at 0.36 m/s against a measured 6–9 m/s.

That is a property of the model, not of the optimizer. In a point-mass-clubhead double pendulum the clubhead-speed-optimal hand speed at impact is identically zero for every parameter value, and releasing the club requires reversing the hub torque, which is the same act as stopping the hands. The derivation, the repairs that fail, and the model change that would fix it are in Why an Optimized Double Pendulum Stops Its Hands.

Read that before drawing conclusions from the objective comparison: the five objectives sit within 0.6% of each other on realism while all of them sit far outside measured golfer kinematics, so their ordering is not evidence about golf.

4 What Would Count Against the Mechanism?

A useful interactive result need not support the proposed mechanism. Examples of disconfirming observations include:

a distal acceleration that remains unchanged when the declared proximal motion and applied torques are removed;
a timing advantage that disappears under matched initial states or reverses under a small plausible parameter change;
a two-hand couple that remains when the hands are coincident or the moment arm is set to zero;
incompatible conclusions from pointwise and forward counterfactuals after their different questions are accounted for; or
force, power, or energy histories that fail the declared numerical closure tolerance.

These checks expose assumptions rather than hiding them. They do not establish that a mechanism occurs in people; they identify what the model predicts and how that prediction can fail.

5 Run It Locally

Clone D-sorganization/Tools, then choose either interface.

5.1 PyQt6 Desktop Interface

cd Tools/src/pendulum_simulator
python -m pip install -e .
python -m double_pendulum_golf

After a double-pendulum run, open the docked Analysis panel and select the Drift Transfer tab. Choose the start and end of the phase to inspect. The tab reports distal energy gain, drift and control grip work, Negative Grip Work, wrist-control work, peak grip force, and peak distal speed, while plotting the power and speed histories. Its displayed proximal-link angular velocity is not an anatomical shoulder or torso measurement. Other model tiers remain unavailable in this tab until their force-allocation contracts are qualified.

For qualified double-pendulum runs, the same panel includes Full-Trajectory Coordinate Force Sources. It reports signed and absolute tangent impulse and generalized work under the shared force-attribution/v1 contract. The Christoffel split uses shoulder-absolute and wrist-relative coordinates. It is a modeled equation-term attribution, not a measured muscle force, and unsupported friction, clamp, or joint-limit terms fail closed rather than being folded into another source.

5.2 React/Tauri Interface

cd Tools/src/pendulum_simulator/pendulum-web
npm install
npm run dev
# Or launch the native desktop wrapper:
npm run tauri dev

Developers using UpstreamDrift can also open the Pendulum Simulator tile. The launcher resolves the sibling Tools provider and its dockable adapter; it does not maintain a second physics implementation.

6 A Productive Review Sequence

Read the hypothesis and falsifier before running the experiment.
Start from the named preset and save its parameters and units.
Inspect vectors and signed power, not animation alone.
Run the matched counterfactual and negative control.
Perturb geometry, inertia, damping, timing, and numerical step size.
Record observations that weaken the interpretation as carefully as those that support it.
Promote a result to the scientific resource only through a deterministic script, frozen inputs, convergence and closure tests, and machine-readable output.

7 Interpretation Boundary

The models illuminate mechanics under declared assumptions. They do not by themselves identify muscle action, scapular coordination, tissue slack, a preferred swing strategy, or a universal route to clubhead speed. A generalized torque is not a muscle, an interaction force is not voluntary effort, and a negative torque is not necessarily negative biological work.

Human falsification requires synchronized whole-body and club kinematics, bilateral hand wrenches, ground reactions, launch outcomes, and appropriately registered activation or stiffness measurements. The governed technical monograph specifies those evidence boundaries and links the deterministic studies behind the article. Its models, claims, and evidence are pinned to UpstreamDrift commit 85cce4d3.

Return to How a Golf Swing Carries Energy for the visual narrative, read the technical summary for a shorter synthesis, or use the technical monograph for the full mathematical and evidentiary treatment.