Attaching The End Effector; R-Axis Tolerable Moment Of Inertia And Acceleration Coefficient - Yamaha YK-X Series User Manual

CHAPTER 3 Installation
6
6-1

Attaching The End Effector

R-axis tolerable moment of inertia and acceleration coeffi-
cient
1) The moment of inertia of a load (end effector and workpiece) that can be
attached to the R-axis is limited by the strength of the robot drive unit and
residual vibration during positioning. It is therefore necessary to reduce the
acceleration coefficient in accordance with the moment of inertia.
2) The R-axis tolerable moment of inertia and the acceleration coefficient ver-
sus R-axis moment of inertia for each robot model are shown in Fig. 3-9 to
Fig. 3-13 on the subsequent pages. The symbols A
respectively indicate the acceleration coefficients of the X-axis, Y-axis and
R-axis. The symbol I
axis and m is the tip mass.
Example: YK500XG
Assume that the mass of the load installed to the R-axis is 1.5kg and the
moment of inertia around the R-axis is 0.1kgm
tip mass parameter is set to 2kg, the robot can be operated by reducing the X,
Y and R-axis acceleration coefficients to 62%, as can be seen from Fig. 3-9.
Be sure to select an optimum tip mass and acceleration coefficient param-
eters that meet the mass of the load and moment of inertia before using the
robot. To make settings for the tip mass and acceleration coefficient, refer to
the separate "YAMAHA Robot Controller User's Manual".
3) Methods for calculating the moment of inertia of the load are shown in Sec-
tion 6-2, however, it is not easy to precisely figure out these values. If a calcu-
lated value smaller than the actual moment of inertia is set, residual vibra-
tions may occur. If this happens, reduce the acceleration coefficient param-
eter even further.
CAUTION
!
• The robot must be operated with correct tolerable moment of inertia and
acceleration coefficients according to the manipulator tip mass and moment
of inertia. If this is not observed, premature end to the life of the drive units,
damage to the robot parts or residual vibration during positioning may result.
• Depending on the Z-axis position, vibration may occur when the X, Y or R-
axis moves. If this happens, reduce the X, Y or R-axis acceleration to an
appropriate level.
• If the moment of inertia is too large, vibration may occur on the Z-axis de-
pending on its operation position. If this happens, reduce the Z-axis accel-
eration to an appropriate level.
(J ) is the moment of inertia of the load around the R-
R R
3-16
, A , and A in each figure
X Y R
2 (1.0kgfcmsec 2 ). When the