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Kinematics
#1
Hello
I tested the kinematics of RoboDK on a scara robot (see attachment)
When I make a linear movement with a fixed speed and acceleration, the time needed to make this movement corresponds well to a trapezoidal speed profile (Robot on target 1 and programme ProgVitesseLineaire)
It is the same for the rotation of a joint (Robot on target 2 and programme ProgVitesse1Joint) but when the movement requires the use of 2 joints (Robot on target 2 and programme ProgVitesse2Joint), the time given by RoboDK corresponds to the time needed to make a rotation corresponding to the sum of the 2 angles on the 2 joints whereas the time needed is the maximum value between the time needed to make the movement on axis 1 and the time needed for the movement on axis 2.
I also observed that when I add a smoothing of the trajectory, all the movements are executed at constant speed and I deduce that the acceleration of the axes is disabled.
Can you tell me if my observations are correct or if I am making mistakes?
Sincerely


Attached Files
.rdk   ModeleVitesse.rdk (Size: 336.72 KB / Downloads: 19)
#2
Your observation is correct: if you use smoothing/rounding RoboDK assumes the robot can keep a constant speed. This may not be the case if you have a small rounding and/or you are moving at high speeds.

Note that RoboDK cycle time calculation is an estimate. More information here:
https://robodk.com/doc/en/General-Cycle-Time.html

Also, the time estimates of a program include the position where the robot comes from.
  




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