Vehicle Tools: Events – Adding compliance to the steering joint

Philipp Kabitzsch

Hello,

At the moment I am working on a motorcycle project. The connection between the fork and the frame is the area of interest. In reality the connection is ensured via two bearings, where I need the reaction forces.

When running some event out of the vehicle toolbox (for example n-Post) the event locks the rotational DOF for the steering movement. To achieve that only non-compliant joints of type revolute, translational or cylindrical are allowed.
The problem I am facing now is, that I need two bushings (or compliant joints) for a realistic representation, because the distribution of the forces at the bearings depends on the direction of the applied loads.

Is there some way to implement that in the model without creating an own event? I already tried the approach with an additional virtual joint as a “soft coupling” which will be locked during the simulation and two bushings, but looking at the results, most of the forces are visible at that joint and not at the bushings.

Thank you!
Philipp

GTT Adam

Hi Philipp,

The steering revolute joint you must define for the driver model could technically be anywhere in the model.

Therefore, you could make the revolute joint connect a dummy body to ground, and then apply a torque to the steering tube via a solver variable that is equal to the amount of torque being passed into the dummy revolute joint.

That would free up the constraint on the steering tube and allow you to connect it to the frame via a bearing from the Machinery Toolkit.

 

Hope this helps!

Adam Reid

GTT Adam

Hi Philipp,

The steering revolute joint you must define for the driver model could technically be anywhere in the model.

Therefore, you could make the revolute joint connect a dummy body to ground, and then apply a torque to the steering tube via a solver variable that is equal to the amount of torque being passed into the dummy revolute joint.

That would free up the constraint on the steering tube and allow you to connect it to the frame via a bearing from the Machinery Toolkit.

 

Hope this helps!

Adam Reid

Philipp Kabitzsch

Thanks a lot, Adam!
Connecting the revolute joint to a dummy body was the solution. But instead of applying a torque to the steering tube, I applied a motion with zero displacement/rotation, because I figured out that there is no torque being passed into the dummy joint. Maybe I have to change it, depending on the kind of analysis, but for now it works and allows me to use the bushings instead of the steering joint.

Thank you for your help!
Philipp