# Tracing a Peritrochoid

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This Demonstration shows a mechanism drawing a peritrochoid.

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Contributed by: Erik Mahieu (March 2017)

Open content licensed under CC BY-NC-SA

## Snapshots

## Details

The radius of the stationary circle is set to , and is the radius of the rolling circle.

A peritrochoid is a sum of two rotations of the rolling circle, expressed in terms of their angle vectors:

1. A rotation around the axes origin: .

2. A rotation around its center: .

The peritrochoid becomes a closed curve after rotations of the rolling circle, where is the denominator of a rational close to .

Reference

[1] V. I. Koutsovoulos. "Peritrochoid Curve & the Wankel Engine." Mechanical Drafting Services (Mar 6, 2017) mechdrafting.net/en/portfolio-item/peritrochoid-curve.

## Permanent Citation