RollingWheel
Joint (no mass, no inertia) that describes an ideal rolling wheel (rolling on the plane z=0)
Library
Modelica/Mechanics/MultiBody/Joints
Description
A joint for a wheel rolling on the x-y plane of the world frame. The rolling contact is considered being ideal, i.e. there is no slip between the wheel and the ground. This is simply gained by two non-holonomic constraint equations on velocity level defined for both longitudinal and lateral direction of the wheel. There is also a holonomic constraint equation on position level granting a permanent contact of the wheel to the ground, i.e. the wheel can not take off.
The origin of the frame frame_a is placed in the intersection of the wheel spin axis with the wheel middle plane and rotates with the wheel itself. The y-axis of frame_a is identical with the wheel spin axis, i.e. the wheel rotates about y-axis of frame_a. A wheel body collecting the mass and inertia should be connected to this frame.
Note
To work properly, the gravity acceleration vector g of the world must point in the negative z-axis, i.e.
inner Modelica.Mechanics.MultiBody.World world(n={0,0,-1});
Parameters
| Name | Label | Description | Data Type | Valid Values |
|---|---|---|---|---|
mo_wheelRadius | wheelRadius | Wheel radius | Scalar | |
mo_stateSelect | stateSelect | Priority to use generalized coordinates as states | Structure | |
mo_stateSelect/choice1 | StateSelect.never | Number | 0 | |
mo_stateSelect/choice2 | StateSelect.avoid | Number | 0 | |
mo_stateSelect/choice3 | StateSelect.default | Number | 0 | |
mo_stateSelect/choice4 | StateSelect.prefer | Number | 0 | |
mo_stateSelect/choice5 | StateSelect.always | Number | 0 |
| Name | Label | Description | Data Type | Valid Values |
|---|---|---|---|---|
mo_x | x | x | Structure | |
mo_x/fixed | fixed | Cell of scalars | true | |
mo_x/start | start | Cell of scalars | ||
mo_y | y | y | Structure | |
mo_y/fixed | fixed | Cell of scalars | true | |
mo_y/start | start | Cell of scalars | ||
mo_z | z | z | Structure | |
mo_z/fixed | fixed | Cell of scalars | true | |
mo_z/start | start | Cell of scalars | ||
mo_angles | angles | angles | Structure | |
mo_angles/fixed | fixed | Cell of vectors of size 3 | true | |
mo_angles/start | start | Cell of vectors of size 3 | ||
mo_der_angles | der_angles | der_angles | Structure | |
mo_der_angles/fixed | fixed | Cell of vectors of size 3 | true | |
mo_der_angles/start | start | Cell of vectors of size 3 | ||
mo_r_road_0 | r_road_0 | r_road_0 | Structure | |
mo_r_road_0/fixed | fixed | Cell of vectors of size 3 | true | |
mo_r_road_0/start | start | Cell of vectors of size 3 | ||
mo_f_wheel_0 | f_wheel_0 | f_wheel_0 | Structure | |
mo_f_wheel_0/fixed | fixed | Cell of vectors of size 3 | true | |
mo_f_wheel_0/start | start | Cell of vectors of size 3 | ||
mo_f_n | f_n | f_n | Structure | |
mo_f_n/fixed | fixed | Cell of scalars | true | |
mo_f_n/start | start | Cell of scalars | ||
mo_f_lat | f_lat | f_lat | Structure | |
mo_f_lat/fixed | fixed | Cell of scalars | true | |
mo_f_lat/start | start | Cell of scalars | ||
mo_f_long | f_long | f_long | Structure | |
mo_f_long/fixed | fixed | Cell of scalars | true | |
mo_f_long/start | start | Cell of scalars | ||
mo_err | err | err | Structure | |
mo_err/fixed | fixed | Cell of scalars | true | |
mo_err/start | start | Cell of scalars |
Ports
| Name | Type | Description | IO Type | Number |
|---|---|---|---|---|
frame_a | implicit | Frame fixed in wheel center point. x-Axis: upwards, y-axis: along wheel axis | input | 1 |