The absolute value of the the time has been added to the rigid body
model state. This value is not directly necessary for calculating the
evolution of the rigid body system, it just facilitates the
implementation of sub-models which are in some way time-dependent.
'w' is now obtained from 'v' using the relation w = sqrt(1 - |sqr(v)|)
and 'v' is stored in the joint state field 'q' and integrated in the
usual manner but corrected using quaternion transformations.
Currently supported solvers: symplectic, Newmark, CrankNicolson
The symplectic solver should only be used if iteration over the forces
and body-motion is not required. Newmark and CrankNicolson both require
iteration to provide 2nd-order behavior.
See applications/test/rigidBodyDynamics/spring for an example of the
application of the Newmark solver.
This development is sponsored by Carnegie Wave Energy Ltd.
This is a more convenient way of maintaining the state or multiple
states (for higher-order integration), storing, retrieving and passing
between processors.
applications/test/rigidBodyDynamics/spring: Test of the linear spring with damper restraint
Damped simple harmonic motion of a weight on a spring is simulated and
the results compared with analytical solution
Test-spring
gnuplot spring.gnuplot
evince spring.eps
This development is sponsored by Carnegie Wave Energy Ltd.
