Block Error Solver Configuration: An implicit 6-DOF joint is attached to a degenerate mass distribution.

Does anyone know the meaning of the error message in the title and how to correct it? It appears when I try to start the simulation in Simmechanics and marks the Solver Configuration Block f(x)=0.

Answer 1

[Christopher Dadswell]

Hi, a reply now probably isn't very useful to you but hopefully it may help someone else. I've been encountering the same problem recently while trying to build a simmechanics model of a quadcopter and have been bashing my head against a wall trying to find a solution.

Whenever I tried to specify a torque to drive a revolute joint I got the 'degenerate mass distribution' error and no amount of reorganising of the model or changing parameters seemed to be able to make it work.

Eventually I tried changing my solver settings and it finally works. It seems that for whatever reason you just need to have a very small step size to make the model run. I'm currently running a fixed step ode5 solver with step size 0.0001 and it runs and behaves sensibly, just a veeery slow simulation.

[Victoria Prince]

For someone who is TRUE newbie, how do I set up for ode5 solver?

[Bolun Dai]

This might not help you any more but this probably will help someone , look for the gear symbol in the simulink interface or the words that appear on the lower right corner and open it. Then in solver options in the solver tab you can find Solver where you can specify what kind of solver would you be using.