modelRelativeVelocity
Measure relative velocity vector between the origins of two frame connectors
Extends from Internal.PartialRelativeSensor (Base class for relative sensor models).
Information
The relative velocity vector between the origins of frame_a and of frame_b are determined and provided at the output signal connector v_rel. This vector is defined as:
r_rel = MultiBody.Frames.resolve2(frame_a.R, frame_b.r_0 - frame_a.r_0); v_rel = der(r_rel);
Via parameter resolveInFrame it is defined, in which frame the velocity vector is resolved:
| resolveInFrame = Types.ResolveInFrameAB. | Meaning |
|---|---|
| world | Resolve vector in world frame |
| frame_a | Resolve vector in frame_a |
| frame_b | Resolve vector in frame_b |
| frame_resolve | Resolve vector in frame_resolve |
If resolveInFrame = Types.ResolveInFrameAB.frame_resolve, the conditional connector "frame_resolve" is enabled and v_rel is resolved in the frame, to which frame_resolve is connected. Note, if this connector is enabled, it must be connected.
Example
If resolveInFrame = Types.ResolveInFrameAB.frame_b, the output vector is computed as:
r_rel = MultiBody.Frames.resolve2(frame_a.R, frame_b.r_0 - frame_a.r_0); v_rel_a = der(r_rel); v_rel = MultiBody.Frames.resolveRelative(frame_a.R, frame_b.R, v_rel_a);
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.Mechanics.MultiBody.Types.ResolveInFrameAB | resolveInFrame | Modelica.Mechanics.MultiBody.Types.ResolveInFrameAB.frame_a | Frame in which output vector v_rel shall be resolved (world, frame_a, frame_b, or frame_resolve) |
Connectors
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.Mechanics.MultiBody.Interfaces.Frame_a | frame_a (from PartialRelativeSensor) | Coordinate system a | |
| Modelica.Mechanics.MultiBody.Interfaces.Frame_b | frame_b (from PartialRelativeSensor) | Coordinate system b | |
| Modelica.Blocks.Interfaces.RealOutput[3] | v_rel | Relative velocity vector resolved in frame defined by resolveInFrame | |
| Modelica.Mechanics.MultiBody.Interfaces.Frame_resolve | frame_resolve | Coordinate system in which v_rel is optionally resolved |