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 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 in a Dwell-Rise-Dwell type motion.. 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. When Period-Ratio is less than 10, this law will give 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. OR for a given limit to Pressure-Angle, this motion-law can give a smaller cam, and/or a shorter motion segment.

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. However, the motion discontinuities at its beginning and end cannot be ignored, as these will lead to shock loading.

For compliant systems of high speed systems (Period Ratio between 2 and 10) the Modified Sine and the Cycloidal are preferred.