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

Polynomial 3-4-5 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 are a function of the Positions at the Start and End of the segment, and duration of the segment.

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


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 one of the Traditional Motion-Laws that produce 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.

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