modelWeakSphericalSpring
Extends from Modelica.Mechanics.MultiBody.Interfaces.PartialTwoFrames (Base model for components providing two frame connectors + outer world + assert to guarantee that the component is connected).
Information
Attribution Notice
This model is an extension of the Spherical block in the Mechanics.MultiBody.Joints package
of the Modelica Standard Library
Copyright © 1998-2016, Modelica Association and DLR.
Block for modeling a spherical joint with a weak constraint. Most Modelica joints introduce strong constraints, i.e. the position of the two frames must be exactly equal. In reality, such strong constraints can cause binding in systems with multiple joints and cause systems to have kinematic loops. This joint overcomes these problems by using a weak formulation of the joint constraints.
The torsional stiffness of this joint in all three directions is determined by the constant c.
Copyright © 2018
ATA ENGINEERING, INC.
ALL RIGHTS RESERVED
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| SI.TranslationalSpringConstant | c_constraint | 1.0e6 | Spring constant |
| SI.TranslationalSpringConstant | c | Spring constants {rx,ry,rz} | |
| SI.Angle | phi_rel0 | {0, 0, 0} | Unstretched spring angles |
| Boolean | animation | false | = true, if animation shall be enabled (show sphere) |
| if animation = true | |||
| SI.Distance | sphereDiameter | world.defaultJointLength | Diameter of sphere representing the spherical joint |
| Advanced | |||
| Types.RotationSequence | sequence_angles | {1, 2, 3} | Sequence of rotations to rotate frame_a into frame_b around the 3 angles used as states |
Connectors
| Type | Name | Default | Description |
|---|---|---|---|
| Interfaces.Frame_a | frame_a (from PartialTwoFrames) | Coordinate system a fixed to the component with one cut-force and cut-torque | |
| Interfaces.Frame_b | frame_b (from PartialTwoFrames) | Coordinate system b fixed to the component with one cut-force and cut-torque |
Components
| Type | Name | Default | Description |
|---|---|---|---|
| Types.Color | sphereColor | Modelica.Mechanics.MultiBody.Types.Defaults.JointColor | Color of sphere representing the spherical joint |
| Types.SpecularCoefficient | specularCoefficient | world.defaultSpecularCoefficient | Reflection of ambient light (= 0: light is completely absorbed) |
| SI.Position[3] | r_rel_0 | Position vector from frame_a to frame_b resolved in world frame | |
| SI.Angle[3] | phi | Three angles to rotate frame_a into frame_b | |
| Frames.Orientation | R_rel | Relative orientation object to rotate from frame_a to frame_b |