| SimMechanics™ | |
Represent prismatic joint with one translational degree of freedom
Joints
The Prismatic block represents a single translational degrees of freedom (DoF) along a specified axis between two bodies. A prismatic joint is one of SimMechanics™ primitive joints, along with revolute and spherical.
The Prismatic block is assembled: you must connect each side of the Joint block to a Body block at a Body coordinate system (CS) point, and the origins of these Body CSs must lie along the prismatic axis, to within assembly tolerances. These Body CS origins do not need to be collocated in space.
You must connect any Joint block to two and only two Body blocks, and Joints have a default of two connector ports for connecting to base and follower Bodies.
A Joint block represents only the abstract relative motion of two bodies, not the bodies themselves. You must specify a reference CS to define the direction of the joint axis.
Prismatic Motion of Follower (blue) Relative to Base (red)
The dialog has two active areas, Connection parameters and Parameters.
The base (B)-follower (F) Body sequence determines the sense of positive motion. Positive translation is the follower moving in the direction of the translation axis.
When you connect the base (B) connector port on the Prismatic 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, Prismatic Base and Follower Body Connector Ports.
When you connect the follower (F) connector port on the Prismatic 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, Prismatic Base and Follower Body Connector Ports.
Using this spinner menu, you can set the number of extra connector ports needed for connecting Joint Actuator and Joint Sensor blocks to this Joint. The default is 0.
The motion of a Prismatic is specified in linear units.
Prismatic Base and Follower Body Connector Ports
Toggle between the Axes and Advanced panels with the tabs.
The entries on the Axes pane are required. They specify the direction of the translational DoF that the Prismatic represents.
This column automatically displays the name of each primitive joint contained in the Joint block. For Prismatic, there is only one primitive joint, a prismatic, labeled P1.
This column automatically displays the type of each primitive joint contained in the Joint block. For Prismatic, there is only one primitive type, labeled Prismatic.
Enter here as a three-component vector the directional axis along which this translational DoF can move. The default vector is [0 0 1]. The axis is a directed vector whose overall sign matters.
Using the pull-down menu, choose the coordinate system (World, the base Body CS, or the follower Body CS) whose coordinate axes the vector axis of translation is oriented with respect to. This CS also determines the absolute meaning of force and motion along the joint axis. The default is World.
The Advanced pane is optional. You use it to control the way SimMechanics simulation interprets the topology of your schematic diagram.
In a closed loop, the simulation internally and automatically cuts one and only one joint.
If you want this particular joint to be weighted preferentially for cutting during the simulation, select the check box. The default is not selected.
Disassembled Prismatic, Joint Actuator, Joint Initial Condition Actuator, Joint Sensor, Joint Stiction Actuator, Revolute, Spherical
See Modeling Degrees of Freedom for more on representing DoFs with Joints.
See Verifying Machine Topology and How SimMechanics™ Software Works for more on closed loops and cutting.
| Point-Curve Constraint | Prismatic-Translational Interface | |
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