Chapter 5 Commissioning operation
ADSD-S-S
51
2).Speed loop integral time constant T
i.
Speed loop integration can eliminate speed steady-state error effectively, response subtle
change of the speed rapidly. In the premise that the mechanical systems would not produce vibration
or noise,
decreasing s
peed loop integral time constant T
i,
that increase the system rigidity, reduce the
steady-state error. If resonance factors in load inertia ratio much large or mechanical system exist,
make sure that speed loop integral time constant is big enough, otherwise the mechanical system is
easy to produce resonance. If load inertia ratio G is set rightly, use the following formula to get
Speed loop integral time constant T
i:
)
(
π
)
(
Hz
k
2
4000
ms
Ti
v
×
≥
3
)
. P
osition loop gain
K
p
P
osition loop gain
decides
the response speed of the p
osition loop gain
directly. In the premise
that the mechanical systems would not produce vibration or noise, increasing the position loop gain
value, as to
accelerate
the reaction speed reduces the position tracking error and the
positioning time.
But too large can cause mechanical system jitter or positioning overshoot. Position loop bandwidth
is not higher than speed loop bandwidth,
general,
Hz)
bandwidth(
loop
speed
*
4
1
Hz)
bandwidth(
loop
position
≤
if l
oad inertia ratio (G)is set right(
M
L
J
J
G
/
=
), so that the position loop gain Kp
calculation as follows:
4
Hz
Kv
2
/
1
Kp
)
(
π
)
(
×
≤
s
2. Gain tuning steps
The choice of position and speed bandwidth must be decided by the mechanical strength and
applications, as the mechanical transmission belt connected rigid is low, the
bandwidth can be set
lowly; as t
he speed reducer drive the ball screw machine stiffness is moderate, the
bandwidth can be
set
moderately; as the direct driving ball screw or linear motor stiffness is high, the
bandwidth can
be set
highly. If the mechanical properties are unknown, would step by step to improve the
frequency width gain until that produces resonance and then just
turn down
the gain only.
Among the servo gain, if change a parameter so that the others. Please not only to change one
of the parameters to be bigger .About the servo parameters to change steps as follows
principle
:
Improve response
Reduce response, suppress vibration and overshoot
1.Improve speed loop gain K
V
2.Reduce speed loop integral time
constant Ti
3.Improve the position loop gain Kp
1.Reduce the position loop gain Kp
2.Increase speed loop integral time constant Ti
3.Reduce speed loop gain Kv
The
steps to adjust the Speed control gain
1. Setting load inertia ratio.
2. Setting time constant speed loop points as larger value
Chapter 5 Commissioning operation
ADSD-S-S
52
3.Speed loop gain could turn up bigger within producing no vibration and abnormal sound ,if there
came up vibration please turn down it slightly.
4.Speed loop integral time constant could turn down litter within producing no vibration ,if there
came up vibration please turn down it greater.
5.When If
the gain cannot
tune
bigger because mechanical system resonance reason occur and can't
get the hope of the response, adjust torque filtering time constant(L007),and then
repeat
the steps of
the operation to improve response again.
The
steps to adjust the position control gain
1). Setting load inertia ratio.
2). Setting time constant speed loop points as larger value
3). Speed loop gain could turn up bigger within producing no vibration and abnormal sound, if there
came up vibration please turn down it slightly.
4). Speed loop integral time constant could turn down litter within producing no vibration ,if there
came up vibration please turn down it greater.
5). Increasing the position loop gain, if there came up vibration please turn down it slightly.
6). When If
the gain cannot
tune
bigger because mechanical system resonance reason occur and can't
get the hope of the response, adjust torque filtering time constant(L007),and then
repeat
the steps of
the operation to improve response again.
7). If you need less time and the smaller position tracking error, adjust the position feed forward can
make it, reference 4-2-4 section, please.
5-2-11 Resonance inhibit
When the mechanical system resonance phenomenon occur, may cause of servo system
stiffness too much and response too fast, reduce gain perhaps may improve well. The drive provide
low-pass filter, not changing the case of the gain and reaching suppress resonance effect. The
parameters about resonant inhibition as show
:
parameters
designation
range
default
value
unit
apply
L007
Torque filtering time
constant
0.10
~
50.00
2.50
ms ALL
Setting by parameter L007. Low-pass filter default is effective. Low-pass filter
decay
high
frequency well, could restrain high frequency resonant and noise well. But
lower
the system
response frequency width and the margin of the phase, the system may become unstable.
Since the servo drive cause the machine occur high frequency vibration, adjust torque filter
time constant Tf to
wipe off
vibration. The smaller numerical ,the better response to control, but with
machine limitations, The larger numerical ,the better restrain high frequency resonant, too big,
would cause reduced the margin of the phase and cause vibration .If load inertia grain G is set
correctly(
M
L
J
J
G
/
=
), need to meet:
)
(
π
)
(
Hz
k
2
2
1000
ms
T
v
f
×
×
≥