defineLinkage: Defines a lever or linkage
In aaronolsen/linkR: 3D Lever and Linkage Mechanism Modeling

Description Usage Arguments Details Value Author(s) See Also

This function takes the joint positions, types and constraints of a lever or linkage mechanism or a set of minimum parameters and creates a list of class "linkage" that forms the basic object for model creation and analysis.

defineLinkage(joint.coor, joint.types, joint.cons, 
              joint.conn = NULL, link.points = NULL, link.assoc = NULL, 
              link.names = NULL, ground.link = NULL, path.connect = NULL, 
              lar.cons = NULL)

`joint.coor`	A matrix of 2D or 3D coordinates that are the joints of a lever or linkage mechanism.
`joint.types`	A vector of single letters indicating the type of constraints acting on each joint. Supported types are "R", "U", "L" and "P". See Details.
`joint.cons`	A list or matrix of 3D constraint vectors that correspond to each joint.
`joint.conn`	A two-column matrix having the same number of rows as `joint.coor`, specifying the two links that each joint connects.
`link.points`	A matrix of points associated with one or more of the links in the linkage (optional).
`link.assoc`	A vector of integers or rownames indicating the link with which each row in `points` is associated. Required if `points` is non-`NULL` but otherwise optional.
`link.names`	A vector of the link names (optional).
`ground.link`	A numeric or link name specifying the ground link of the linkage.
`path.connect`	A list of vectors, each specifying the points to connect (in sequence) with lines when drawing. This parameter is only used when calling the function `drawLinkage`.
`lar.cons`	A list specifying long-axis rotation constraints on links with S-joints on each end. This feature will eventually be added into the `joint.conn` input parameter as network connections.

Please see linkR Resources for a tutorial on how to use the linkR package and the linkR example gallery for several examples (code and animations) of different linkages that can be created using linkR.

a list of class "linkage" with the following elements:

`joint.coor`	A matrix of 2D or 3D coordinates that are the joints of a lever or linkage mechanism.
`joint.cons`	A vector of single letters indicating the type of constraints acting on each joint.
`joint.types`	A list or matrix of 3D constraint vectors that correspond to each joint.
`joint.links`	A matrix specifying the joints connecting to each link. Used by the `animateLinkage` function.
`joint.paths`	"Path fragments" along the linkage network, used by the `animateLinkage` function to solve for the position of unresolved joints.
`joint.conn`	A two-column matrix having the same number of rows as `joint.coor`, specifying the two links that each joint connects.
`joint.init`	The initial position of the joints in the linkage.
`ground.joints`	The ground joints in the linkage.
`points`	A matrix of points associated with any of the links in the linkage.
`points.assoc`	The links with which each point is associated.
`link.assoc`	A vector of integers or rownames indicating the link with which each row, if input.
`link.names`	A vector of the link names.
`point.connect`	A list of vectors, each of which specifies linkage-associated points to connect in sequence with a path. This is only used by `drawLinkage` when creating the linkage visualization.
`link.lcs`	Local coordinate systems assigned to each link which will be transformed with the associated link for kinematic analysis.
`lar.cons`	Constraints on long-axis rotation.
`num.links`	The number of links in the linkage.
`dof`	The number of degrees of freedom of the linkage. Currently, this may not be accurately estimated for all linkages.