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Ta b l e 2 . 2 . Inter hit travel times
Hit
Hit
0
1
2
3
4
5
6
7
0
-
50
100
50
100
150
100
200
1
50
-
50
100
50
100
150
150
2
100
50
-
150
100
50
200
100
3
50
100
150
-
50
100
50
150
4
100
50
100
50
-
50
100
100
5
150
100
50
100
50
-
150
50
6
100
150
200
50
100
150
-
100
7
200
150
100
150
100
50
100
-
100
2a
5b
7a
100
1c
4d
3a
6c
0
Fig. 2.4. Flat metal sheet to be punched
change in tools because that the turret will rotate. The cost of rotation is 60 time units,
which exceeds the 50 inter-hit time unit. This means that the modified inter
hit time
between locations 1 and 2 is 60 time units. From the home to any hit is not affected. The
modified inter
hit times are shown in Table 2.3. This information is used for TSP. One
TSP solution for Table 2.2 is
{
0 , 1 , 2 , 3 , 4 , 5 , 6 , 7
}
, with a cost of 830 .WeusedtheDE
heuristic to obtain tool sequence of c
a , and the cost is 410 . As can
be seen a better solution is obtain by the latter. Let us explain how we obtained the tool
sequence. Solving the TSP using DE, the sequence obtaineed is
d
b
a
c
{
2 , 5 , 6 , 8 , 7 , 4 , 1 , 3
}
or
{
1 , 4 , 5 , 7 , 6 , 3 , 0 , 2
}
. What we do is to refer to Fig 2.4 and get the labels that corrspond
to this sequence as
{
c , d , b , a , c , a , a
}
. Hence the optimum sequence is c
d
b
a
c .
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