Examples and tips
PROGRAMMING MANUAL
246
Revi
si
on 3.0
Example 3
fig. 21
The mechanical system uses a servo motor with an 17-bit absolute
encoder. The mechanical gear ratio of the gearbox is 1:6.31. One
rotation of the pulley moves the moving part on the belt 320 mm.
The total length of the belt, and therefore the total moving range of
the motion part, is 4160 mm.
The mechanical measurement units must be mm. This means that
all axis parameters and commands given to Trajexia are expressed
in mm. Using the same procedure as in example 1, the equation
expressing the relationship between user units and encoder counts
is:
Therefore:
One solution is:
Note that we have not used the pulley radius in the calculation. This
is to avoid the use of
π
, which cannot be expressed as a fractional
number). In toothed pulleys, the number of teeth and mm per tooth
is commonly used.
The calculation of the multiturn limit setting is:
17-bit absolute
encoder
1:6.31
Gear
r = 320/(2*PI)
1 turn = 320mm move
Total length (perimeter) of belt: 4160
M
r
Pn202
Pn203
UNITS =
2
17
encoder_counts
1 motor_revolution 1 pulley_revolution
6.31 motor_revolution
320mm
1 pulley_revolution
320
2
6.31
mm
encoder_counts
=
.
17
.
.
.
.
.
Pn202
Pn203
UNITS =
2
320
17
6.31
2
1000
17
631
=
2
5
8.125
631
= 2
12
631
= 2
12
125
2
3
631
= 2
9
125
.
.
9
UNITS = 2 = 512
Pn202 = 631
Pn203 = 125
I52E-EN-03.book Seite 246 Freitag, 29. Juni 2007 11:55 11