Defining Jerk / Ramps; Jerk Limitation - Parker Compax3S025V2 Operating Instructions Manual

Parker EME
4.1.8.

Defining jerk / ramps

4.1.8.1
Without jerk
according to
VDI2143
In this chapter you can read about:

Jerk limitation.....................................................................................................................................91

Ramp upon error / deenergize..........................................................................................................92
Jerk limitation
Jerk
The jerk (marked with "4" in the drawing below) describes the change in
acceleration (derivation of the acceleration)
The maximum change in acceleration is limited via the jerk limitation.
A motion process generally starts from a standstill, accelerates constantly at the
specified acceleration to then move at the selected speed to the target position.
The drive is brought to a stop before the target position with the delay that has
been set in such a manner as to come to a complete stop at the target position. To
reach the set acceleration and deceleration, the drive must change the acceleration
(from 0 to the set value or from the set value to 0).
This change in speed is limited by the maximum jerk.
According to VDI2143 the jerk is defined (other than here) as the jump in
acceleration (infinite value of the jerk function).
This means that positionings with Compax3 are without jerk according to VDI2143,
as the value of the jerk funciton is limited.
Motion sequence
1
2
3
4
1: Position
2: Velocity
3: Acceleration
4: Jerk
High changes in acceleration (high jerks) often have negative effects on the
mechanical systems involved. There is a danger that mechanical resonance points
will be excited or that impacts will be caused by existing mechanical slack points.
You can reduce these problems to a minimum by specifying the maximum jerk.
Jerk
3
Unit: Length unit/s Range: 0 ... 10 000 000
192-120101 N11 C3I11T11 November 2007
Setting up Compax3
t
t
t
t
Standard value:
1 000 000
91