Simscape Multibody angle constraint translation bug

Hi,

There seems to be a bug i Simscape Multibody angle constraint. If I follow up the contraint with a frame that is also translated to define the next body at an offset, it will not translate it. I even introduced it as an additional frame with just translation. But the rigid body will not be trasnlated. If I do the ame thng with say 6dof joint, there are no issues. Please let me know if I'm doing something wrong.

[Steve Miller]

Hashem - you will need to share your model for us to help you.

Answer 1

[Hashem Ashrafiuon]

Steve,

Thank you for getting back to me. Please see the attached. It's a simple model of a differential drive wheeled moblie robot. You can ignore most of the model. Please see the rigid transform called "pitch end". I have a caretsian translation [0,0,5] cm. That should move the whole robot 5 cm up relative to the base plane. But t doesn't. In fact, you can see that using any translation value in any of the three directions has no effect. Thanks.

Hashem

Answer 2

[Steve Miller]

Hi Hashem

1. Your Rigid Transform Pitch end ensures that the F frame it creates is 5 cm away from the B frame along the z-axis of the B Frame.
2. The z-axis of the B frame, however, is pointing along the global -X axis, so the F frame is within the plane of the Chassis Cir solid.

Your Pitch Angle Constraint is forcing the angle between the z-axes of the two frames to which it is attached to be 90 degrees. Since the B Frame of the constraint is rigidly connected to the world frame, it is forcing the z axis of its F frame to be in the XY world plane.

--Steve

Answer 3

[Hashem Ashrafiuon]

Thank you.