Siemens SINUMERIK 828D Turning, Руководство по эксплуатации функций

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B1: Continuous­path Mode, Exact Stop, LookAhead
3.4 Dynamic adaptations
Basic Functions
Function Manual, 09/2011, 6FC5397-0BP40-2BA0
185
Principle
During processing and via all the axes involved in the path, the controller cyclically establishes the minimum of all
the limit frequencies to be the limit frequency (f) for the adaptation of the dynamic response and calculates the
relevant time window (t
adapt
) from this:
t
adapt
= 1 / f
The size of the relevant time window t
adapt
determines the further behavior:
1. The time needed to change the velocity is less than t
adapt
:
The acceleration rates are reduced by a factor > 1 and ≤ the value written in machine data:
MD20465 ADAPT_PATH_DYNAMIC (adaptation of the path dynamics)
The reduction in acceleration rate increases the time taken to change the velocity.
The following cases are different:
- The acceleration rate is reduced with a value less than MD20465 so that the process lasts for t
adapt
[s].
The permitted reduction does not need to be fully utilized.
- The acceleration time is reduced with the value written in MD20465. The process lasts less than t
adapt
despite the reduced acceleration. The permitted reduction was fully utilized.
2. The time needed to change the velocity is greater than t
adapt
:
No dynamic response adaptation is required.
Example
The following example is intended to show the effect of the "adaptation of the dynamic path response" function
on traversing motions with acceleration and without jerk limiting (BRISK).
The following parameters are assumed:
The path involves the 3 axes X = AX1, Y = AX2, Z = AX3.
For path motions in which axis AX2 is involved, all deceleration and acceleration processes that would last less
than T
AX2
are adapted.
If only axes AX1 and/or AX3 are involved in path motions, all deceleration and acceleration processes that would
last less than T
AX1
= T
AX3
are adapted.
The relevant time window is marked t
adapt...
in the figures below.
MD20465 $MC_ADAPT_PATH_DYNAMIC[0] = 1.5
MD20460 $MC_LOOKAH_SMOOTH_FACTOR = 1.0
MD32440 $MA_LOOKAH_FREQUENCY[AX1] = 20 Hz
T
AX1
= 1/20 Hz = 50 ms
MD32440 $MA_LOOKAH_FREQUENCY[AX2] = 10 Hz T
AX2
= 1/10 Hz = 100 ms
MD32440 $MA_LOOKAH_FREQUENCY[AX3] = 20 Hz T
AX3
= 1/20 Hz = 50 ms
Note
To illustrate the effect of dynamic response adaptation, the value for the smoothing factor
(MD20460) is set to "1", whereby the "smoothing of the path velocity" function is practically
deactivated.