Ramp Cam-Law, Motion-Law

Motion-Values: With the SEGMENT-EDITOR or the BLEND-POINT EDITOR, you ...

CAN specify the:

Position at the START of the segment.

CAN specify the:

Position at the END of the segment.

CANNOT specify the:

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

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

The Jerk values are a function of the Positions at the Start and End of the segment, and its duration.

Segment Parameters.

SE-Ramp-SegmentParameters

Start-Fraction × 100 = % of Segment-Width for Acceleration
End-Fraction × 100 = % of Segment-Width for Deceleration

Notes:

0 ≤ Start-Fraction ; 0 ≤ End-Fraction ; 1 ≥ End-Fraction + Start-Fraction.

If Start Fraction + End Fraction < 1, there is a constant-velocity. You cannot specify the value of the constant-velocity.

If Start Fraction + End Fraction = 1, there is not a constant velocity.

If Start Fraction = End Fraction, the segment is 'Symmetrical'

If Start Fraction End Fraction, the segment is 'Asymmetrical'.

MotionLaw-Ramp

Examples of Start and End Fractions Segment-Parameters

Start Fraction = End-Fraction, the segment is Symmetric
Start-Fraction ≠ End-Fraction, the segment is Asymmetric
Start Fraction = End Fraction = 0.5 ; the Segment is the Cycloidal Motion-Law.

Applications Notes

Use a Ramp with a constant-velocity to reduce the peak velocity.

This might reduce the pressure angle. However, the peak acceleration will increase.

Use the Ramp Motion-Law to design an 'asymmetrical motion'.
Asymmetrical Motion

Asymmetrical Motion

ASYMMETRICAL MOTION

The segment is asymmetrical when the Start-Fraction End-Fraction

In the image, the:

Start-Fraction is 0.7
End-Fraction is 0.3.
Start-Fraction + End-Fraction = 1,

Thus, there is not a constant-velocity between the start and end fractions.

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