*SetJointFrictionLugre() - single joint

Sets the friction properties for a joint with friction.

*Applicable for the MotionSolve SolverMode only.

Syntax

*SetJointFrictionLugre(varname, bristle_stiffness, 
                                 damping_effects, viscous_effects)

Arguments

varname
The variable name of the joint.
Data type: varname
bristle_stiffness
Specifies the LuGre bristle stiffness to be used. See Comments below.
Default: 100
Data type: real
damping_effects
Specifies the LuGre damping coefficient for the stiction regime. See Comments below.
Default: 0.316
Data type: real
viscous_effects
Specifies the coefficient for the viscous damping force that occurs when relative sliding actually begins. See Comments below.
Default: 0.0004
Data type: real

Example

*BeginMDL( the_model, "Model" )
 *StandardInclude(FILE)
 *Point( p_block, "Block" )
 *Body( b_0, "Block", p_block, , , , )
 *TransJoint( j_0, "Translation", b_0, B_Ground, p_block, VECTOR, V_Global_X )
 *SetBodyInertia( b_0, 1.0, 1000.0, 1000.0, 100.0, 0.0, 0.0, 0.0 )
 *Set( b_0.usecm, true )
 *SetJointFriction( j_0, true, 0.3, 0.25, ACTIVE_STATIC, 0.1, 0.01, SLIDING_ONLY, PRELOAD, NO_REACTION_FORCE, NO_BENDING_MOMENT, , 1000, 10, , , , 0.0, 1.0, 1.0, 1.0, 1.0 )
 *SetJointFrictionLugre( j_0, 110, 0.31, 0.0005 )
*EndMDL()

Context

*BeginMdl()

*DefineSystem()

*DefineAssembly()

*BeginContext()

Comments

This statement is used to set the LuGre parameters for the friction model of a joint in "Non-Compliant" mode. This statement is valid for the MotionSolve SolverMode and if friction is enabled for the joint using the *SetJointFriction() statement.
bristle_stiffness
Specifies the bristle stiffness in the LuGre model. It models the stiffness resisting micro-deformation in the friction element.
damping_effects
Defines the damping coefficient for the pre-displacement (or stiction) regime. Its main role is to damp out bristle vibrations in the pre-displacement regime.
viscous_effects
Represents viscous damping. This is primarily responsible for the increase in friction force with the increase in the slip velocity.