Hi,

I have some problems with modelling reaction wheel in Adams. I need to analyze behaviour of separation mechanism that set both linear velocity along Z axis and angular velocity around Z axis to fly-away mass. In order to stabilize fly-away mass that is separated from a base and ejected, I want to use one reaction wheel, that will be rotating around axis aligned to Z axis. Reaction wheel is rotating with angular velocity of 23000 deg/s. Mechanism is analyzed in no gravity condition (separation and latter movement will take place in space). Unfortunately I am encountering some issues during analysis. First of all, angular velocity magnitude of reaction wheel and fly-away mass changes throughout the time and constantly decreasing, same is happening with angular momentum magnitude of fly-away mass and reaction wheel.

Picture 1, https://files.engineering.com/getfile.aspx?folder=...

Picture 2 https://files.engineering.com/getfile.aspx?folder=...

They should not be changing, because after separation there are no forces acting on components. I am using timestep that is set at 1e-3s. Characteristics of the curves are also unsettling:

Picture 3 https://files.engineering.com/getfile.aspx?folder=...

With smaller time step i.e. 1e-5 magnitudes of angular velocity and angular momentum are constant, but while plotting components of them, this is what I get (some peaks occur randomly):

Picture 4 https://files.engineering.com/getfile.aspx?folder=...

To clarify, model without reaction wheel was also implemented and results have been validated. I assume that, issues are connected with reaction wheel.
In order to connect reaction wheel with fly-away mass I am using revolute joint, motion is assigned to the revolute joint (23000 deg/s around Z axis), initial angular velocity of fly-away mass is set at 0 deg/s around Z axis. Could you help me with finding out where the problem may lay?

Thanks!

• https://files.engineering.com/getfile.aspx?folder=38817d49-2673-4313-ae1a-b