*PerpAxesJointPair()

Creates a perpendicular axes joint pair.

Syntax

*PerpAxesJointPair(joint_name,"joint_label",body_1, body_2, origin, POINT|VECTOR, point_1|vector_1, POINT|VECTOR, point_2|vector_2)

Arguments

joint_name
The variable name of the perpendicular axes joint pair.
Data type: varname
joint_label
The descriptive label of the perpendicular axes joint pair.
Data type: label
body_1
The first body or body pair constrained by the perpendicular axes joint pair.
Data type: Body or BodyPair
body_2
The second body or body pair constrained by the perpendicular axes joint pair.
Data type: Body or BodyPair
origin
The location of the perpendicular axes joint pair.
Data type: Point or PointPair
POINT|VECTOR
A keyword that indicates the alignment method.
point_1|vector_1
An entity variable referring to a Point, PointPair, Vector, or VectorPair which is based on the above keyword.
Data type: Point or Vector pair
POINT|VECTOR
A keyword that indicates the alignment method.
point_2|vector_2
An entity variable referring to a Point, PointPair, Vector, or VectorPair which is based on the above keyword.
Data type: Point or Vector pair

Example

*BodyPair(body_1,    "First body",    p_1)
*BodyPair(body_2,             "Second body",   p_2)
*VectorPair(vector_1,         "First vector")
*VectorPair(vector_2,         "Second vector")
*PointPair(p_origin, "origin")

*PerpAxesJointPair(jt1, "Orientation joint", body_1, 
                                             body_2, 
                                             p_origin, 
                                             VECTOR, 
                                             vector_1, 
                                             VECTOR, 
                                             vector_2)

Context

*BeginMdl()

*DefineAnalysis()

*DefineSystem()

Properties

Table 1.
Property Returns Data Type Description
b1 BodyPair The first body pair constrained by the perpendicular axes joint pair.
b2 BodyPair The second body pair constrained by the perpendicular axes joint pair.
i MarkerPair The marker pair on b1.
j MarkerPair The marker pair on b2.
l PerpAxesJoint Left perpendicular axes joint.
label string The descriptive label of the perpendicular axes joint pair.
r PerpAxesJoint Right perpendicular axes joint.
state boolean Control state (TRUE or FALSE).
varname string The variable name of the perpendicular axes joint pair.

Comments

The individual joints of a *PerpAxesJointPair() can be referred to as joint_name.l (left perpendicular axes joint) and joint_name.r (right perpendicular axes joint).

A perpendicular axes joint constrains the relative rotation between two bodies in such a way that the specified axes attached to the two bodies always remain mutually perpendicular.

When a point is used (instead of a vector) to define an axis, it is obtained as the direction from the origin of the joint to the specified point.