*Coupler()

Creates a coupler for two or three joints.

Syntax

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

Example

*BeginMDL(model, "The Model")
*Point(p_0, "Point 0")
*Point(p_1, "Point 1")
*Point(p_2, "Point 2")
*Point(p_3, "Point 3")
*SetPoint(p_0, 1, 2, 3)
*SetPoint(p_1, 4, 5, 6)
*SetPoint(p_2, 7, 8, 9)
*SetPoint(p_3, 10, 11, 12)
*Body(b_0, "Body 0", p_0)
*Body(b_1, "Body 1", p_1)
*Body(b_2, "Body 2", p_2)
*Body(b_3, "Body 3", p_3)
*RevJoint(j_0, "Rev Joint 0", b_0, b_1, p_0, V_Global_Y)
*RevJoint(j_1, "Rev Joint 1", b_1, b_2, p_1, V_Global_Z)
*RevJoint(j_2, "Rev Joint 2", b_2, b_3, p_2, V_Global_X)
*Coupler(c_0, "Coupler 0", 2JOINT, j_0, j_1, ROT, ROT)
*SetCoupler(c_0, 50)
*SetCoupler(c_0, USER, `USER( 300, 1, 2)`)
*SetLocalUserDLLFlag(c_0, TRUE)
*SetLocalUserDLL(c_0, " C:/Test/mycoupler.py ")
*SetLocalUserFuncname(c_0, "COUSUB")
*SetLocalUserFunction(c_0, PYTHON)
*Set(c_0.local_der1_funcname, COUXX)
*Set(c_0.local_der2_funcname, COUXX2)
*EndMDL()

Context

Properties

Table 1.
Property	Returns Data Type	Description
j1	Joint	The first joint constrained by the coupler.
j2	Joint	The second joint constrained by the coupler.
j3	Joint	The third joint constrained by the coupler.
label	string	The descriptive label of the coupler.
ratio1	real	The ratio is the displacement of joint 1 divided by the displacement of joint 2 for each joint's respective direction of displacement.
ratio2	real	The ratio is the displacement of joint 1 divided by the displacement of joint 3 for each joint's respective direction of displacement.
state	boolean	Control state (TRUE or FALSE).
varname	string	The variable name of the coupler.
id	long integer	The solver ID of the coupler.
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 can constrain a revolute, translational, or cylindrical joint. When a coupler contains a cylindrical joint, either of its two degrees of freedom (translational or rotational) may be constrained by specifying the TRANS or ROT flag, respectively. The TRANS or ROT flag for the seventh, eigth, and ninth argument applies to the first joint, second joint, and third joint, respectively. The TRANS or ROT argument needs to be specified for cylindrical joints only.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.