*Motion()

Applies a motion to a specified joint or constrains the motion between two markers.

Syntax

*Motion(motion_name,"motion_label",JOINT, joint_name, TRANS|ROT)

*Motion(motion_name,"motion_label",MARKERS, i_marker_name, j_marker_name, direction)

Arguments

motion_name: The variable name of the motion.; Data type: varname
motion_label: The descriptive label of the motion.; Data type: label
JOINT|MARKERS: Type of motion applied to a joint or two markers.; Data type: keyword
joint_name: The joint to which the motion is applied.; Data type: CylJoint, RevJoint, or TransJoint
TRANS|ROT: This argument indicates whether the motion is applied to the translational or rotational degree of freedom when using a cylindrical joint.
i_marker_name: The first of two markers for which displacement is being controlled.; Data type: Marker
j_marker_name: The second of two markers for which displacement is being controlled.; Data type: Marker
direction: The direction of the constraint.; Data type: X, Y, Z, B1, B2, or B3

Example

*RevJoint(j_crank_piv, "Crank pivot", 
                          b_crank, 
                          B_Ground, 
                          p_crank_pivot, 
                          p_crank_pivot_axis)
*Motion(crank_rot, "Crank rotation", 
                      JOINT, j_crank_piv)
*SetMotion(crank_rot, DISP, '360D*TIME')
*Motion(motion_0, "Motion 0", MARKERS, marker_5, marker_6, B2)

Context

*BeginMdl()

*DefineAnalysis()

*DefineSystem()

Properties

Table 1.
Property	Returns Data Type	Description
label	string	The descriptive label of the motion.
state	boolean	Control state (TRUE or FALSE).
varname	string	The variable name of the motion.
id	long integer	The solver ID of the motion.
jt	CylJoint, RevJoint, or TransJoint	The joint to which the motion is applied.
im	Marker	The first of two markers for which displacement is being controlled.
jm	Marker	The second of two markers for which displacement is being controlled.
direction	string	The direction of the constraint.
type		The type of motion specified: DISP, VEL, or ACCL.
value	string	The value or solver expression for the motion.

Comments

A *Motion() statement can be specified for any revolute joint, translational joint, or cylindrical joint. However, a motion cannot be specified for a joint in compliant mode.

The TRANS|ROT flag is required only when a motion is applied to a cylindrical joint.

If no *SetMotion() statement is present, the displacement of the joint is set to zero.