Mitsubishi Electronics CR751-D Welding System User Manual


 
2-15
2 Robot arm
2.2.3 Relationships Among Mass Capacity, Speed, and Acceleration/Deceleration Speed
This robot automatically sets the optimum acceleration and deceleration speeds and maximum speed, according
to the load capacity and size that have been set, and operates using these automatically set speeds.
To achieve that, it is necessary to correctly set the actual load data (mass and size of hand and work) to be used.
However, vibration, overheating and errors such as excessive margin of error and overload may occur, depending
on the robot operation pattern or ambient temperature.
In this case, reduce the speed and the acceleration and deceleration rate before continuing to use. This is done by
accessing the robot program and adjusting the speed settings (Ovrd) and the acceleration and deceleration set-
tings (Accel).
If a setting is performed in such a way that it falls below the mounted load, the life span of the mechanism ele-
ments used in the robot may be shortened. In the case of a work requiring a high degree of accuracy, set up the
load correctly and use the robot by lowering the ratios of the acceleration and deceleration speeds.
(1) Setting Load Capacity and Size (Hand Conditions)
Set up the capacity and size of the hand with the "HNDDAT*" parameter (optimum acceleration/deceleration
setting parameter), and set up the capacity and size of the work with the "WRKDAT*" parameter. Numbers 0 to 8
can be used for the asterisk (*) part. Designate the "HNDDAT*" and "WRKDAT*" parameters to be used using
the "LoadSet" command in a program.
For more details, refer to the separate "Instruction Manual/Detailed Explanation of Functions and Operations."
It is the same meaning as "LoadSet 0.0" if not using the "LoadSet".
<Factor default settings>
Note) The position of the center of gravity is located at the center of the surface at the bottom of the shaft. Set
the X, Y and Z center of gravity positions for the tool coordinate directions (the Z center of gravity position
will be a plus for downward directions).
2.2.4 Vibrations at the Tip of the Arm during Low-Speed Operation of the Robot
Vibrations at the tip of the arm may increase substantially during the low-speed operation of the robot, depending
on the combination of robot operation, hand mass and hand inertia. This problem occurs when the vibration count
specific to the robot arm and the vibration count of the arm driving force are coming close to each other. These
vibrations at the tip of the arm can be reduced by taking the following measures:
1) Change the robot's operating speed by using the Ovrd command.
2) Change and move the teaching points of the robot.
3) Change the hand mass and hand inertia.
Hand mass
kg
size X
mm
size Y
mm
size Z
mm
center-of-gravity
position X mm
center-of-gravity
position Y mm
center-of-gravity
position Z mm
HNDDAT*
3.0 99.0 99.0 76.0 0.0 0.0 38.0
WRKDAT*
0.0 0.0 0.0 0.0 0.0 0.0 0.0