*CouplerPair()

Creates a coupler pair.

Syntax

*CouplerPair(coupler_name,"coupler_label",2JOINT|3JOINT joint_1, joint_2, [joint_3] TRANS|ROT, TRANS|ROT, [TRANS|ROT])

Arguments

coupler_name: The variable name of the coupler pair.; Data type: varname
coupler_label: The descriptive label of the coupler pair.; Data type: label
2JOINT|3JOINT: Set to 3JOINT for a three joint coupler, otherwise, set to 2JOINT.
joint_1: The first joint or joint pair constrained by the coupler pair.; Data type: JointPair
joint_2: The second joint or joint pair constrained by the coupler pair.; Data type: JointPair
joint_3: The third joint constrained by the coupler pair. Required if *SetCouplerType() is 3JOINT .; Data type: JointPair
TRANS|ROT: See Comments .
TRANS|ROT: See Comments .
TRANS|ROT: Required if *SetCouplerType() is 3JOINT. See Comments.

Example

*BeginMDL( the_model, "Model", "11.0.0.130-HWDesktop" )
 *BodyPair( b_0, "Body 0", p_0, , , , , false, false )
 *PointPair( p_0, "Point 0" )
 *SetPoint( p_0, LEFT, , -50 )
 *SetBodyInertia( b_0, LEFT )
 *Set( b_0.usecm, true )
 *SetOrientation( b_0.cm.l, TWOAXES, ZX, DXDYDZ, , , , DXDYDZ )
 *PointPair( p_1, "Point 1" )
 *SetPoint( p_1, LEFT, 50, -50 )
 *BodyPair( b_1, "Body 1", p_1, , , , , false, false )
 *Set( b_1.usecm, true )
 *RevJointPair( j_0, "Joint 0", b_0, B_Ground, p_0, VECTOR, V_Global_Y )
 *TransJointPair( j_1, "Joint 1", b_1, B_Ground, p_1, POINT, p_0 )
 *CouplerPair( c_0, "Coupler 0", 2JOINT, j_0, j_1, TRANS, TRANS )
 *SetCoupler( c_0, LEFT )
 *SetCoupler( c_0, , -5 , -5 )
*EndMDL()

Context

Properties

Table 1.
Property	Returns Data Type	Description
j1	JointPair	The first joint pair constrained by the coupler pair.
j2	JointPair	The second joint pair constrained by the coupler pair.
j3	JointPair.	The third joint pair constrained by the coupler pair.
l	Coupler	Left coupler.
label	string	The descriptive label of the coupler pair.
r	Coupler	Right coupler.
state	boolean	Control state (TRUE or FALSE).
varname	string	The variable name of the coupler pair.
ratio	real	The coupler ratio between first joint and the second joint.
ratio2	real	The coupler ratio between first joint (j1) and the third joint (j3).
usr_sub	string	User expression passed to the solver dll in the case of a user defined coupler.
use_local_dll	boolean	Valid values are "true" or "false". True switches the flag on to use a local function instead of default.
local_func_type	string	Keyword to set the type of function to be used. Valid choices are: DLL, PYTHON, and MATLAB.
local_dll	string	String containing the path to the local function file.
local_funcname	string	The function name or subroutine name called by the entity. The default name is "COUSUB".
local_der1_funcname	string	The function name or subroutine name for the first derivative. The default name is "COUXX". See ^Comments^ (below).
local_der2_funcname	string	The function name or subroutine name for the second derivative. The default name is "COUXX2". See ^Comments^ (below).

Comments

A coupler pair can constrain a revolute, translational, or cylindrical joint pair. When a coupler pair contains a cylindrical joint pair, either of its two degrees of freedom (translational or rotational) may be constrained by specifying the TRANS or ROT flag. The TRANS or ROT flag for the seventh, eighth, and ninth arguments applies to the first joint pair, second joint pair, and third joint pair, respectively. Therefore, TRANS or ROT argument needs to be specified for cylindrical joints only.

The individual couplers of a *CouplerPair()can be referred to as coupler_name.l (left coupler) and coupler_name.r (right coupler).Symmetry is not applicable for a user-defined coupler pair. The local dll flag and function name needs to be set individually for the left and the right side, as shown in example above.

The function names for the first order and second order derivatives cannot be set using the MotionView graphical user interface. Use the general *Set statement to set the function names.