Dzhanibekov reference
A rigid body with fixed principal moments I₁ < I₂ < I₃, initialized near the unstable intermediate-axis rotation. Its torque-free Euler equations conserve both |L| and rotational energy.
REDUCED MODEL CONTROLS
Move the shape clock. Watch the resemblance move with it.
The rigid reference conserves angular momentum and rotational energy. The Jitterbug analogue prescribes a periodic inertia tensor, so shape work may change kinetic energy while angular momentum remains the primary invariant.
DISPLAY-ONLY ATTITUDE PROJECTION
Rigid instability / shape-driven analogue
The wireframes depict inertia and body axes, not a validated Fuller hinge mechanism. Animation is a projection of the calculated trajectories and adds no physical claim.
EXPLORATORY COMPARISON
CALCULATING
- Best geodesic RMS
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- Best excursion correlation
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- Rigid reversals
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- Analogue reversals
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- Rigid |L| drift
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- Rigid energy drift
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- Analogue |L| drift
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- Analogue energy variation
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- Best time scale
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- Physical equivalence
- FALSE
WHAT IS BEING COMPARED?
Quaternion paths, not screenshots.
Jitterbug analogue
A positive-definite inertia tensor changes with a bounded periodic shape coordinate λ(t). It is a reduced variable-inertia model—not a multibody Fuller Jitterbug with vertices, hinges, constraints and internal momentum coupling.
Distance
d(q₁,q₂) = 2 acos(|q₁·q₂|) respects the fact that q and −q describe the same attitude. Global orientation, time shift and one scalar time rescaling are allowed during comparison.
Interpretation
“Partial resemblance” means both trajectories contain a large flip-like motif, but their complete attitude histories remain far apart. It is evidence for a research question, not identity of mechanism.