11.1.1 2D Constraints

There are only two 2D generalized coordinate constraints. The wide variety of standard 2D constraints cannot be meaningfully converted to generalized constraints; only constraints which attach exactly two bodies together such that only one degree of freedom remains between them are generally useful.
The arguments given to the generalized coordinate constraints are of the same form as the arguments given to the standard constraints. However, each of these constraints requires an additional argument to specify the name of, and an initial guess for, the new symbol that represents the added degree of freedom.

The 2D generalized coordinate constraints.

Note that there is a clear distinction between a master and slave bodies. The slave body is the one that will be represented by the single new generalized coordinate. Thus, the slave body cannot be the ground body. The master body may be the ground body, another body represented by standard coordinates, or another body represented by generalized coordinates that was created with another generalized constraint. The master-slave relationship cannot be circular; the master-slave chain must originate from the ground, or from a standard body. Also, a slave body cannot be a slave to more than one master body.
Another restriction on the arguments to generalized coordinate constraints is that the axis objects, axis1 and axis2, must each be defined entirely on a single body. While standard constraints allow axis objects to span multiple bodies (such as a line originating on one body and ending on another) generalized coordinate constraints do not.

Example

The following example shows a standard constraint and a generalized coordinate constraint that could be used to perform exactly the same function in a model.

Here are two functionally equivalent constraints.

In[1]:=

Out[4]=

Out[5]=