UR5 trajectory on 5kg payload

Technical Questions
1

0kg

5kg

Upper picture : 0kg payload
Down picture : 5kg payload

Axis X : time(ms)
Axis Y : degree(rad)

hello

I compared the trajectory of UR5 between 0kg payload and 5kg payload in same function(moveL) same waypoint.

And I extract the angle of joint1,which is target_qd_1 and actual_qd_1.

The trajectory of 0kg payload is smooth and stable.

But, The trajectory of 5kg payload is not smooth and unstable.

Why the different is happen?

Thank you.

2

Hi kseo,

Did you remember to set the payload and Center-of-Gravity correctly?
Installation->General->Payload

payload
payload673×650 38.9 KB

3

Hi jor

Of course, I set the Payload-Mass and the Center of Gravity.

And I use UR5, CB-series.

Thank you.

4

Hi kseo,

I’ve tried to look at your figures again.
The joint is tracking the Target position correctly. (So I should have been able to deduce that you set the payload and Center-of-Gravity correctly)

Robot movement is dependent on what type of move you are doing.
If you are doing a moveJ, then the robot will try to move the Tool to the target position as fast as possible.
The pathPlanner might do some weird shaping, since the robot is not infinitely rigid.

The pathPlanner is primarily concerned with the position of the tool, not so much the angle of individual joints
Have you considered to look at the tool position instead of a joint?

5

Hi jor

I used the moveL function.

The program consist of three waypoint.

And three waypoints is on a line.
Only position Y is different

eg. p1 = ( 200, 250, 400)
p2 = ( 200, 400, 400)
p3 = ( 200, 550, 400)

and the velocity is 300mm/s

P1

P2

v1

v2

The tool position is same different like joint.

However, the tool velocitiy is smooth and stable each condition.

Thank you.