A Traditional Motion-Law. Also named a Parabolic motion-law.
Segment-Editor AND Blend-Point Editor
CAN specify its:
The Start-Position usually flows from the End-Position of the Previous-Segment
CANNOT specify its:
Segment Editor only
Cv = 2.000
Ca = ±4.000
Cj = ± ∞
* Nominal: the discontinuities in its acceleration, with infinite jerk, will incite vibrations, so that the actual peak acceleration - in a real mechanical system - will be at least 2 times the nominal peak acceleration.
This Motion-Law has been used frequently in the past because it has the lowest nominal acceleration of the Traditional Motion-Laws. However, it has infinite jerk at three points: the start, end, and at its cross-over. This makes it a very poor choice form a dynamic viewpoint. Infinite-Jerk incites vibrations in any mechanical system.
The actual acceleration of the load being driven by Constant-Acceleration motion will always be significantly higher than the nominal value, because of induced vibrations.
For this reason, this segment should only be used in applications where inertia effects are small or even insignificant.
Pressure Angle Considerations
This segment produces a relatively large pressure angle - and so might need a large cam for a given lift. The pressure angle for this segment varies quite severely throughout this Motion-Law indicating that it is unsuitable for roller follower applications because of the severe accelerations imposed on the roller that will tend to induce roller slip.
This law performs badly in terms of drive torque considerations. All of the torque factor curves for this law exhibit a discontinuity, indicating shock loading and noise in operation. Particularly notable is the sudden reversal of the inertia torque factor, and hence of the torsional strain energy, at the cross-over of the motion segment. These reversals will contribute further to noise, shock loading and vibration during operation.