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SetCouple
2D/3D

SetCouple[sym, eqn] builds a CoupleSystem object in which the value of the symbol sym is sought that satisfies the equation eqn.
SetCouple[{sym1, sym2, ... , symn}, {eqn1, eqn2, ... , eqnn}] uses the n equations to try to solve for n symbols.
SetCouple[{syms, ... }, {equations1, options1}, {equations2, options2}, ... ] attempts to find the values of the syms that satisfy all of the equationsi at different configurations. This usage is only meaningful if Time is included in the optionsi.

• The CoupleSystem object is solved with SolveCouple.
• The following options can be given:

• The Time option specifies the value of time, T. The Time option must be present if SetCouple is used with a system that is time dependent.
Time->Free causes time to be treated as a dependent variable, which adds one degree of freedom to the model and requires one additional equation for each occurrence of Time->Free.
SetCouple[{syms, ... }, {equations1, Time->t1, options1}, {equations2, Time->t2, options2}, ... ] attempts to find the values of the syms that satisfy all of the equationsi at different points in time.
• If InitialGuess is unspecified, SetCouple uses the initial guesses from the current model, as obtained from
LastSolve.
• The Compiled and Solution options should only be specified at the end of the argument list, not among the sublists of equationsi, because their effect is global.
• If the Solution option is specified with too low a setting (such as if Solution->Location is specified but the equations eqni contains velocity terms), SetCouple automatically adjusts to a higher-order solution.
• See also: FindTime, SetFree.

Further Examples

Load the Modeler2D package and define a simple model.

Here we rebuild the RelativeDistance1 constraint in the help model so that the distance between the link end and the ground pivot is parameterized by the new variable endDistance. This constraint is identical to the original constraint with the addition of endDistance in place of the constant 4.0.

Now we build a CoupleSystem object that can be used to find the value of endDistance that causes the Y coordinate of the origin of the slider, Y3, to be equal to 1.9 when time, T, is equal to 0.2.

Here we solve the CoupleSystem object to find the value of endDistance and the configuration of the entire model.

See HelpModel2D.


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