Triple-Harmonic: Zero-Jerk-at-Crossover Motion-Law

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Triple-Harmonic: Zero-Jerk-at-Crossover Motion-Law

Triple-Harmonic: 'Approximate Zero-Jerk at Crossover'

Crossover : the point at which the Acceleration changes to Deceleration.

When Jerk is zero, and the also the acceleration changes from a positive value to a negative value, we say the Motion-Law has Zero Jerk at Crossover. Jerk changes slowly.

When acceleration changes slowly, and it is also near to zero, the velocity changes slowly.

If there is backlash in the mechanical transmission between the follower and the tool, then backlash is traversed as the force changes from a positive action to a negative action. Since the velocity happens to be changing slowly, the impact velocity should also be small, with this motion-law.

(Note: the Force will change when the total force on the mechanical element changes sign. The force in the system is not only a function of the Motion-Law. The Force may also include: constant, spring, damping and other forces).


To use this Motion-Law:

1.Select Triple Harmonic

2.Open the Segment Editor.

3.Edit the Segment Parameters:

First Harmonic = 9*Π/4

Second harmonic = 0.0

Third Harmonic = -3*pi/4

MotionDesigner calculates the third harmonic, based on the fact that the segment always creates a D-R-D segment.

Harmonic Settings that give an Acceleration with Zero Jerk at Crossover

Harmonic Settings that give an Acceleration with Zero Jerk at Crossover

MT-CamLaw-TripleHarmoinc-ZeroJErkatCrossover