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J
JB_142559904-Participant
4-Participant
October 14, 2025
Solved

Flexible component's constraints in assembly

  • October 14, 2025
  • 2 replies
  • 835 views

Hello,

 

I'm asking help to know if there is a way in assembly to make constraint play on values of a flexible element. I have a 6DOF robot arm saved as an flexible asm. To place it I'm currently making his base's origin concurrent with the floor's one (cf. constraints.png). 

In order to make it looks like the right position, I change each angle of rotation he had (which are all 6 flexible elements) degrees by degrees which is painfull (cf. flexible elements list.png). 

Regarding this issue, I want to know if it's possible to add an other constraint on the robot arm, this time with gripper and make both of his constraints change the value of the flexible element instead of changing all by hand.

PS : I'm a using Creo 11

 

Best answer by pausob

That does not seem quite right way to use flexibility to model robots.

I'd treat the robot assembly as a mechanism and placed it into the parent assembly with a couple of rigid connections.

One constraining the base to the base coordinate system and one that constraints its gripper to the coordinate system that describes the gripper pose.

If the robot mechanism can achieve the gripper pose, then the joint angles needed will be figured out automatically...

2 replies

P
19-Tanzanite
pausob19-TanzaniteAnswer
19-Tanzanite
October 14, 2025

That does not seem quite right way to use flexibility to model robots.

I'd treat the robot assembly as a mechanism and placed it into the parent assembly with a couple of rigid connections.

One constraining the base to the base coordinate system and one that constraints its gripper to the coordinate system that describes the gripper pose.

If the robot mechanism can achieve the gripper pose, then the joint angles needed will be figured out automatically...

    J
    JB_142559904-ParticipantAuthor
    4-Participant
    October 16, 2025

    Thank you ! It's exactly what I was looking for but I didn't know the features actually exists and no one in my company neither.

    tbraxton
    22-Sapphire II
    tbraxton22-Sapphire II
    22-Sapphire II
    October 14, 2025

    I would agree with @pausob that your use of flexible components in the context of your model is not the best way to capture the design intent in Creo. Apply assembly constraints (or use the defined joints) to lock down the required DOFs in your model and set limit positions. You can use the drag model or explicitly position the gripper of the arm, and the kinematic chain will be correctly represented in the models.

    | Joint Type | Degrees of Freedom | Description |
|--------------|----------------------------|-----------------------------------------------------------|
| Rigid | 0 | No movement allowed; component is fixed in place. |
| Pin | 1 rotation | Allows rotation around a single axis (like a hinge). |
| Slider | 1 translation | Allows linear motion along one axis. |
| Cylinder | 1 rotation + 1 translation | Rotation and translation along the same axis. |
| Planar | 2 translation + 1 rotation | Movement in a plane and rotation about its normal axis. |
| Ball | 3 rotation | Full rotational freedom (like a ball-and-socket joint). |
| Bearing | 1 rotation | Rotation along a defined trajectory. |
| Weld | 0 | Fixed using coordinate system and offset; used in welds. |
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