Explore a double Cardan drive for mechanical shaft-drive design. Matching the two operating angles and intermediate-yoke phasing cancels the output speed fluctuation. The intermediate shaft still speeds up and slows down.
Example buttons set both A and B. Both models share one clock and one scale. Change each condition in its own input fields.
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Play to rotate the shafts at the entered rpm.
At high speeds, frame sampling can make rotation look reversed or stationary. No automatic slowing is applied. Reduce the playback multiplier to inspect motion.
Angles above 45° are kinematic comparisons. Actual joints may not accommodate this angle.
Solid: output / input. Dashed: intermediate / input. The vertical line is the current input angle. Both charts share the same vertical scale.
Solid: output / input. Dashed: intermediate / input. The vertical line is the current input angle. Both charts share the same vertical scale.
Even with constant input speed, the white output mark can speed up and slow down. Use the min–max range and speed chart alongside the instantaneous value.
δ=0° means the two yokes on the intermediate shaft are parallel. This model uses the planar Z arrangement. Equal β₁ and β₂ with δ=0° gives uniform output. Output angle is travel relative to the initial pose.
Input and output shaft lengths are 110 mm each; double-joint centre spacing is 160 mm. A and B use the same dimensions. These lengths do not affect the speed ratio.
Rigid-body kinematics with coplanar shaft axes. Ripple is (maximum ratio − minimum ratio) × 100%. The mean output speed equals the input; this is not a reduction gear. Friction, play, inertia, vibration, life and actual-part interference are excluded. Input ranges are not product ratings.
φ = atan2(cos β · sin θ, cos θ)
ωout / ωin = cos β / (1 − sin²β · sin²θ)Angles are unwrapped across complete turns.
ψ=fβ₁(θ), χ=gβ₂(ψ+δ), g=f⁻¹
dχ/dθ = f′β₁(θ) · g′β₂(ψ+δ)