Polynomial 4-5-6-7 Cam-Law, Motion-Law

Polynomial 4-5-6-7 is a Traditional Motion-Law


In the Segment-Editor or the Blend-Point Editor you ...

CAN specify the:

Position at the START of the segment.

The Position value usually flows from the Previous-Segment.

CAN specify the:

Position at the END of the segment.

CANNOT specify the

The Velocity values at the Start and End are 0 units/s

The Acceleration values at the Start and End are 0 units/s2

The Jerk values at the Start and End are 0 units/s3


See Also: Tutorial 4: Edit the Start and End of a Traditional Segment

CamLaw-Polynomial4567

Application Notes

Dynamic Performance:

This Motion-Law is recommended in applications where the period ratio is between about 5 and 10.

Pressure Angle Considerations

This is a Traditional Motion-Laws. It gives a relatively large pressure angle - and so might need a large cam for a given lift.

Drive Torques

This Motion-Law produces a high peak torque requirement.


When using this Motion-Law the user should be aware of:

High peak velocity.
High peak acceleration.
High value of crossover jerk . Only the Modified-Trapezoidal (finite jerk motions) has a greater peak crossover jerk.
Tiny displacements at the start and end of the segment for significant changes to the X–axis Value - about 0.02% displacement after 5% of Segment-Width.

This this would require extremely precise machining, a large cam, large Cam-Rise, or a high resolution encoder for a servo system.

If possible, increase the segment width when using this Motion-Law - for example by deleting a Dwell segment.

Motion Coefficients

Cv = 2.188

Ca = 7.513

Cj = 42

Cj at Crossover = -52.0

See Motion-Law Coefficients


Tutorial and Reference Help Files for MechDesigner and MotionDesigner 13.2 + © Machine, Mechanism, Motion and Cam Design Software by PSMotion Ltd