Hi,
I'm trying to simulate a model and I'm struggling to get what SM solvers errors messages means. I know from a math point of view what is a linear system with no solution, but the problem is that the solver error doesn't give too much of a clue and Equation Browser points to a continuous system of 9 equations:
der(body1.Q[1]) * $dynState.set1.s[2,1] + der(body1.Q[2]) * $dynState.set1.s[2,2] + der(body1.Q[3]) * $dynState.set1.s[2,3] + der(body1.Q[4]) * $dynState.set1.s[2,4] + wheelOnGround1.body.w_a[1] * $dynState.set1.s[2,5] + wheelOnGround1.body.w_a[2] * $dynState.set1.s[2,6] + wheelOnGround1.body.w_a[3] * $dynState.set1.s[2,7] = $dynState.set1.x[2]
-------------
der(body1.Q[1]) * $dynState.set1.s[1,1] + der(body1.Q[2]) * $dynState.set1.s[1,2] + der(body1.Q[3]) * $dynState.set1.s[1,3] + der(body1.Q[4]) * $dynState.set1.s[1,4] + wheelOnGround1.body.w_a[1] * $dynState.set1.s[1,5] + wheelOnGround1.body.w_a[2] * $dynState.set1.s[1,6] + wheelOnGround1.body.w_a[3] * $dynState.set1.s[1,7] = $dynState.set1.x[1]
-------------
body1.w_a[3] = wheelOnGround1.body.w_a[3] * revolute1.R_rel.T[3,3] - wheelOnGround1.body.w_a[1] * revolute1.R_rel.T[1,3]
-------------
0 = 2 * der(body1.Q[4]) * body1.Q[4] + 2 * der(body1.Q[3]) * body1.Q[3] + 2 * der(body1.Q[1]) * body1.Q[1] + 2 * der(body1.Q[2]) * body1.Q[2]
-------------
der(body1.Q[1]) * $dynState.set1.s[3,1] + der(body1.Q[2]) * $dynState.set1.s[3,2] + der(body1.Q[3]) * $dynState.set1.s[3,3] + der(body1.Q[4]) * $dynState.set1.s[3,4] + wheelOnGround1.body.w_a[1] * $dynState.set1.s[3,5] + wheelOnGround1.body.w_a[2] * $dynState.set1.s[3,6] + wheelOnGround1.body.w_a[3] * $dynState.set1.s[3,7] = $dynState.set1.x[3]
-------------
body2.w_a[1] = -2.0 * (body1.Q[1] * der(body1.Q[4]) + body1.Q[2] * der(body1.Q[3])) + 2.0 * (body1.Q[3] * der(body1.Q[2])) + 2.0 * (body1.Q[4] * der(body1.Q[1]))
-------------
der(body1.Q[1]) * $dynState.set1.s[4,1] + der(body1.Q[2]) * $dynState.set1.s[4,2] + der(body1.Q[3]) * $dynState.set1.s[4,3] + der(body1.Q[4]) * $dynState.set1.s[4,4] + wheelOnGround1.body.w_a[1] * $dynState.set1.s[4,5] + wheelOnGround1.body.w_a[2] * $dynState.set1.s[4,6] + wheelOnGround1.body.w_a[3] * $dynState.set1.s[4,7] = $dynState.set1.x[4]
-------------
body2.w_a[1] = wheelOnGround1.body.w_a[3] * revolute1.R_rel.T[1,3] + wheelOnGround1.body.w_a[1] * revolute1.R_rel.T[3,3]
-------------
body1.w_a[3] = -2.0 * (body1.Q[3] * der(body1.Q[4])) + 2.0 * (body1.Q[4] * der(body1.Q[3])) + -2.0 * (body1.Q[1] * der(body1.Q[2])) + 2.0 * (body1.Q[2] * der(body1.Q[1]))
I know that variables now are out of context, but what means $dynState.set1.s[x,y] for example? I thinks that is part of the state selection system, but is really hard for me to have a clue of what to think about this system of equation when it has those dummy variables (?). Maybe I'm missing something in SM docs about the solver errors, but I couldn't find anything meaningful. Is there any specific docs on solver errors ?
I'm a beginner in multi-body modeling and such systems are really hard to debug. Also, could someone points out a good text on multi-body dynamics specially something about solver issues?
Thanks.
