Simple-Harmonic Motion-Law

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Simple-Harmonic Motion-Law

Simple Harmonic Motion Cam-Law, Motion-Law

A Traditional Motion-Law.

Motion Description

This Motion-Law has the lowest maximum nominal velocity of all the Traditional Motion-Laws. However, it also produces infinite jerk at its start and end.

This makes it a poor choice form a dynamic viewpoint if you use it between Dwell Segments. However, you can usefully apply it between Flexible-Polynomial segments, with which it is possible to remove the acceleration discontinuities at its start and end.


You CAN control the:


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


You CANNOT control the:

Start Velocity and End Velocity

Start Acceleration and End Acceleration

Start Jerk and 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.

Simple-Harmonic-Motion Motion-Law

Simple-Harmonic-Motion Motion-Law

Motion-Law Coefficients

Velocity Coefficient :

Acceleration Coefficient :

Jerk Coefficient :

Jerk at Crossover :

Application Notes

Dynamic Performance:

This law should be used in applications where inertia loading is not very significant. For values of Period-Ratio less than 10, the use of this law gives rise to shock loading, noise and vibration during operation.

The actual acceleration at the load being driven by this Motion-Law is always more than the nominal value, and for this reason, this segment should only be used in mechanical applications where inertia effects are insignificant.

Pressure Angle Considerations:

This is one of the Traditional Motion-Laws that produce a relatively small pressure angle - and so might allow a smaller cam for a given lift.

Drive Torques:

When considering drive torques in isolation, the nominal torque for this Motion-Law is the best of Traditional Motion-Laws - it has both the lowest value and the smoothest variation throughout the segment. For compliant systems of high speed systems (period ratio between 2 and 10) the Modified Sine and the Cycloidal are preferred.