YASKAWA MOTOMAN YRC1000 - Page 119

System Setup
9 - 119
1. Split the tool up into individual parts because the weight and center of gravity can be
determined approximately. It is not necessary to split it up precisely. The tool is used to
deal with unfinished parts.
2. Calculate the weight and center of gravity of each part on the flange coordinates. This
can be an approximate value. Calculate the moments of inertia of the larger parts (the
moment of inertia does not have to be calculated for small parts). To calculate the
moment of inertia, see the calculation of the moment of inertia for a hexahedron and
cylinder.
wi: Weight of the nth parts [kg]
(xi, yi, zi): Centre of gravity of the nth parts (on the flange coordinates) [mm] Icxi, Icyi,
Iczi: Moments of inertia of the nth parts [kgm²]
3. The center of gravity for the whole tool is calculated on the basis of the following
formula.
4. The center of gravity at the center of gravity for the whole tool is calculated on the basis
of the following formula.
xg = {w1 * x1 + w2 * x2 +.... + wi * xi} / (w1 + w2 +.... + wi)
yg = {w1 * y1 + w2 * y2 +.... + wi * yi} / (w1 + w2 +.... + wi)
zg = {w1 * z1 + w2 * z2 +.... + wi * zi} / (w1 + w2 +.... + wi)
Ix = {w1 * ((y1 - yg)2 + (z1 - zg)2) * 10
-6
+ Icx1} + {w2 * ((y2 - yg)2 + (z2 - zg)2) * 10
-6
+
Icx2}
..............................
+ {wi * ((yi - yg)2 + (zi - zg)2) *10
-6
+ Icxi}
Iy = {w1 * ((x1 - xg)2 + (z1 - zg)2) * 10-6 + Icy1} + {w2 * ((x2 - xg)2 + (z2 - zg)2) * 10
-6
+
Icy2}
..............................
+ {wi * ((xi - xg)2 + (zi - zg)2) * 10
-6
+ Icyi}
Iz = {w1 * ((x1 - xg)2 + (y1 - yg)2) * 10
-6
+ Icz1} + {w2 * ((x2 - xg)2 + (y2 - yg)2) * 10
-6
+ Icz
.............................
+ {wi * ((xi - xg)2 + (yi - yg)2) * 10
-6
+ Iczi}