Polynomial 3-4-5 Motion-Law

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Polynomial 3-4-5 Motion-Law

Polynomial 3-4-5 Cam-Law, Motion-Law

A Traditional Motion-Law.  Its name is often reduced to Poly345

You CAN specify the:


The Start-Position usually flows from the End-Position of the Previous-Segment.


You CANNOT specify the:

Start-Velocity, End-Velocity

Start-Acceleration, End-Acceleration

Start-Jerk, End-Jerk

Segment Parameters




See also : MD-Globe-www-24 Tutorial 5: Edit the Start of a Traditional Motion-Law.

See also : MD-Globe-www-24 Tutorial 9: Asymmetrical Motions.

Polynomial 3-4-5 Motion-Law / Cam-Law

Polynomial 3-4-5 Motion-Law / Cam-Law

Motion-Law Coefficients

Velocity Coefficient :

Acceleration Coefficient :

Jerk Coefficient :

Jerk at Cross-over :

Application Notes

This segment has finite jerk throughout. It also gives a relatively low nominal peak velocity, but a relatively high peak nominal acceleration. This Motion-Law also has a relatively low jerk value at the cross-over point (the mid-point).

Dynamic Performance:

This Motion-Law is recommended for applications where the period ratio is between 5 and 10, particularly where the input drive is flexible and has backlash. It also performs relatively well from a residual vibration viewpoint.

Pressure Angle Considerations

This is a Traditional Motion-Laws that produces a relatively small pressure angle - and so might allow a smaller cam for a given lift and pre-prescribed maximum pressure angle.

Drive Torques

Both the nominal drive torque characteristics and the actual drive torques for low period ratio values are reasonable for this law. The peak values and smooth variation of the drive torque during the motion segment makes it suitable in applications where the input drive is relatively flexible or exhibits backlash.