Constant parallel relationship between two body axis vectors
First Generation/Constraints & Drivers
This content is specific to Simscape™ Multibody™ First Generation software. First-generation features are slated to be deprecated and should be avoided.
The two Bodies connected by a Parallel Constraint are restricted in their relative rotational motion. The Parallel Constraint is connected on either side to a Body CS, one on each Body. A vector aB defined in one Body CS on the base body remains parallel to a second vector aF defined in another Body CS on the follower body.
The Parallel Constraint block requires that:
You specify the initial direction to which both vectors must remain parallel.
Constraints restrict relative degrees of freedom (DoFs) between a pair of bodies. Locally in a machine, they replace a Joint as the expression of the DoFs. Globally, Constraint blocks must occur topologically in closed loops. Like Bodies connected to a Joint, the two Bodies connected to a Constraint are ordered as base and follower, fixing the direction of relative motion.
You can connect a Constraint & Driver Sensor to any Constraint block, but not a Driver Actuator. The Constraint & Driver Sensor measures the reaction forces/torques between the constrained bodies.
The dialog has two active areas, Connection parameters and Parameters.
The base (B)-follower (F) Body sequence determines the sense of positive motion. Positive rotation is the follower rotating in the right-handed sense about the rotation axis.
When you connect the base (B) connector port on the Parallel Constraint block to a Body CS Port on a Body, this parameter is automatically reset to the name of this Body CS. See the following figure, Parallel Constraint Base and Follower Body Connector Ports.
When you connect the follower (F) connector port on the Parallel Constraint block to a Body CS Port on a Body, this parameter is automatically reset to the name of this Body CS. See the following figure, Parallel Constraint Base and Follower Body Connector Ports.
Using this spinner menu, you can set the number of extra connector
ports needed for connecting Constraint & Driver Sensor blocks
to this Constraint. The default is
Parallel Constraint Base and Follower Body Connector Ports
Enter the axis vector defining the initial direction of the
two body axis vectors ab, af. These body axis
vectors are restricted to always remain parallel to this initial axis.
The default is
[1 0 0].
Using the pull-down menu, choose the coordinate system (World,
the base Body CS, or the follower Body CS) whose coordinate axes the
initial Parallel constraint axis is
oriented with respect to. This CS also determines the absolute meaning
of reaction forces/torques at this Constraint. The default is
See Constraining and Driving Degrees of Freedom for more on restricting DoFs with Constraints.