modelPartialFriction
Base model of Coulomb friction elements
Information
Basic model for Coulomb friction that models the stuck phase in a reliable way.
This procedure is implemented in a "clean" way by state events and leads to a mixed continuous/discrete systems of equations if friction elements are dynamically coupled which have to be solved by appropriate numerical methods. The method is described in (see also a short sketch in UsersGuide.ModelingOfFriction):
- Otter M., Elmqvist H., and Mattsson S.E. (1999):
- Hybrid Modeling in Modelica based on the Synchronous Data Flow Principle. CACSD'99, Aug. 22.-26, Hawaii.
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Integer | Unknown | 3 | Value of mode is not known |
| Integer | Free | 2 | Element is not active |
| Integer | Forward | 1 | v_relfric > 0 (forward sliding) |
| Integer | Stuck | 0 | v_relfric = 0 (forward sliding, locked or backward sliding) |
| Integer | Backward | -1 | v_relfric < 0 (backward sliding) |
| Advanced | |||
| SI.Velocity | v_small | 1e-3 | Relative velocity near to zero (see model info text) |
Components
| Type | Name | Default | Description |
|---|---|---|---|
| SI.Velocity | v_relfric | Relative velocity between frictional surfaces | |
| SI.Acceleration | a_relfric | Relative acceleration between frictional surfaces | |
| SI.Force | f0 | Friction force for v_relfric=0 and forward sliding | |
| SI.Force | f0_max | Maximum friction force for v_relfric=0 and locked | |
| Boolean | free | = true, if frictional element is not active | |
| Real | sa | Path parameter of friction characteristic f = f(a_relfric) | |
| Boolean | startForward | = true, if v_relfric=0 and start of forward sliding | |
| Boolean | startBackward | = true, if v_relfric=0 and start of backward sliding | |
| Boolean | locked | = true, if v_relfric=0 and not sliding | |
| Integer | mode | Mode of friction (-1: backward sliding, 0: stuck, 1: forward sliding, 2: inactive, 3: unknown) |