• FreeSystem is the head of the data object returned by SetFree.
• The output format of the FreeSystem data object is FreeSystem[solution, <>], where solution is the setting for the Solution option in SetFree.
• The second element of a FreeSystem object is True for nonlinear systems, and False for linear ones.
• FreeSystem is not intended to be used external to Mech.
• See also: SolveFree.
Load the Modeler2D package and define a simple model.
Here we build a FreeSystem object that can be used to simulate the underconstrained motion of the help model when the constraint that controls the rotation of the crank has been removed. Before calling SetFree, a velocity solution is generated with SolveMech so that initial conditions for the location and velocity of each body will be available.
Because the help model has only one body with nonzero mass and one applied load (the link body has a 10-unit mass and a 10-unit applied load in the X direction), the instantaneous free acceleration is somewhat predictable. The X acceleration of the link body, X3dd, is equal to 1.0.
Here we integrate the free acceleration of the help model with respect to time for four seconds.
Here is a plot of the X position of the link. The link is initially decelerating until its X coordinate reaches a local minimum, and then it accelerates the other way.