Fixed spatial relationship between frames
Simscape / Multibody / Frames and Transforms
This block applies a time-invariant transformation between two frames. The transformation rotates and translates the follower port frame (F) with respect to the base port frame (B). Connecting the frame ports in reverse causes the transformation itself to reverse. The frames remain fixed with respect to each other during simulation, moving only as a single unit. Combine Rigid Transform and Solid blocks to model compound rigid bodies.
B
— Base frameFrame with respect to which you specify the transforms.
F
— Follower frameFrame to which you apply the transforms.
Rotation: Method
— Method for specifying the rotation transformMethod to use to specify the rotation transform between the base and follower frames. The table summarizes the available options.
Method | Description |
---|---|
None | Constrain the base and follower frames to share the same orientation. |
Aligned Axes | Set frame rotation by aligning two follower frame axes with two base frame axes. |
Standard Axis | Specify frame rotation as an angle about a standard axis (x, y, or z). |
Arbitrary Axis | Specify frame rotation as an angle about a general [x, y, z] axis. |
Rotation Sequence | Specify frame rotation as a sequence of three elementary rotations. |
Rotation Matrix | Specify frame rotation as a right-handed orthogonal rotation matrix. |
Aligned Axes
Select two pairs of base-follower frame axes.
Parameter | Description |
---|---|
Pair 1 | First pair of base-follower frame axes to align. |
Pair 2 | Second pair of base-follower frame axes to align. Axis choices depend on Pair 1 axis selections. |
Standard Axis
Select a standard rotation axis, resolved in the base frame, and specify the follower frame rotation angle.
Parameter | Description |
---|---|
Axis | Standard rotation axis (X, Y, or Z) resolved in the base frame. |
Angle | Follower frame rotation angle about the rotation axis with respect to the base frame. |
Arbitrary Axis
Select a general 3-D rotation axis, resolved in the base frame, and specify the follower frame rotation angle.
Parameter | Description |
---|---|
Axis | General rotation axis [X Y Z] resolved in the base frame. |
Angle | Follower frame rotation angle about the rotation axis with respect to the base frame. |
Rotation Sequence
Specify a sequence of three elementary rotations about the selected permutation of x, y, and z axes. These rotation sequences are also known as Euler and Tait-Bryan sequences. The rotations are those of the follower frame relative to the frame selected in the Rotate About parameter.
If you set the Rotate About
parameter to Follower Frame
, the
follower frame rotates about its own axes. These axes change
orientation with each successive rotation. If you set the
Rotate About parameter to
Base Frame
, the follower
frame rotates about the fixed base frame axes.
Parameter | Description |
---|---|
Rotation About | Frame whose axes to rotate the follower frame about. |
Sequence | Sequence of axes about which to apply the elementary rotations. |
Angles | Three-element vector with elementary rotation angles about the axes specified in the Sequence parameter. |
Rotation Matrix
Specify the 3×3 transformation matrix of a proper
rotation between the base and follower frames. The matrix
must be orthogonal and have determinant +1. The default
matrix is [1 0 0; 0 1 0; 0 0 1]
.
Translation: Method
— Method for specifying the translation transformMethod to use to specify the translation transform between the base and follower frames. The table summarizes the available options.
Method | Description |
---|---|
None | Make base and follower frames coincident. This method requires no parameters. |
Cartesian | Specify a 3-D translation in terms of Cartesian coordinates |
Standard Axis | Specify a 1-D translation along the X, Y, or Z axis |
Cylindrical | Specify a 3-D translation in terms of cylindrical coordinates |
Cartesian Axis
Specify the Offset of the follower frame with respect to the base frame. This is the 3-D translation vector that brings the base frame into coincidence with the follower frame. Select or enter a physical unit.
Standard Axis
Specify the offset of the follower frame with respect to the base frame along the base frame X, Y, or Z axis. Select or enter a physical unit.
Parameter | Description |
---|---|
Axis | Axis the follower frame translates along |
Offset | Translation of the follower frame with respect to the base frame along the specified axis |
Cylindrical
Specify in cylindrical coordinates the translation that brings the base frame into coincidence with the follower frame. Select or enter a physical unit.
Parameter | Description |
---|---|
Radius | Distance between the origin of the follower frame and the Z axis of the base frame. This is the cylindrical radius coordinate. |
Theta | Rotation angle of the line connecting base and follower frame origins with respect to the base frame X axis. This is the cylindrical azimuth coordinate. |
Z Offset | Distance between base and follower frame origins along the base frame Z axis. This is the cylindrical length coordinate. |
Reference Frame | Transform Sensor | Variable Brick Solid | World Frame