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Disassembled Cylindrical

Joint with misaligned base and follower axes containing one revolute and one prismatic joint primitives

Library

Joints/Disassembled Joints

Description

The Disassembled Cylindrical block represents a composite joint, one translational and one rotational degrees of freedom (DoF) along and about a pair of specified misaligned axes between two bodies. SimMechanics™ simulation automatically assembles (aligns) the two axes at simulation start when it defines a machine's assembled configuration.

A cylindrical joint is composite, with two DoFs and a single specified axis: a prismatic primitive translating along the axis, and a revolute primitive rotating about the axis. There are no constraints between the two primitives.

Disassembled Cylindrical Axes of Follower (blue) and Base (red)

Satisfying Joint Requirements

A Joint block represents the relative degrees of freedom between two bodies, not the bodies themselves.

You must connect any Joint block to two and only two Body blocks, the base and the follower. All Joints have a default of two connector ports for these connections, defining the direction of joint motion (base to follower). You connect each side of the Joint block to these Body blocks at a Body coordinate system (CS) point.

You specify the joint primitive axes, if any, in the Joint dialog. The two disassembled primitive joint axes are associated, in order, with the base and follower Bodies, respectively.

You cannot connect an Actuator or Sensor to a Disassembled Joint.

Assembly Restrictions on Disassembled Joints

This Joint block is disassembled: the connected Body CS origins do not need to be spatially collocated points or lie within the span of prismatic primitives, if any.

You can only use a Disassembled Joint block within a closed loop. One loop can have no more than one disassembled joint.

Dialog Box and Parameters

The dialog has two active areas, Connection parameters and Parameters.

Connection Parameters

Current base

When you connect the base (B) connector port on the Disassembled Cylindrical 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, Disassembled Cylindrical Base and Follower Body Connector Ports.

Current follower

When you connect the follower (F) connector port on the Disassembled Cylindrical 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, Disassembled Cylindrical Base and Follower Body Connector Ports.

Disassembled Cylindrical Base and Follower Body Connector Ports

Parameters

There is one Axes tab.

The entries on the Axes tab are required. They specify the directions of the two misaligned axes of the translational-rotational DoFs that the Disassembled Cylindrical represents.

Name

This column automatically displays the names of the two misaligned rotation axes attached to base and follower bodies, respectively.

Axis of Action [x y z]

Enter here as two three-component vectors the two misaligned directional axes along and about which the base and follower bodies respectively can translate and rotate. The default vectors are [1 0 0] and [0 1 0], respectively. The axes are directed vectors whose overall signs matter.

Reference CS

Using the pull-down menu, choose the coordinate systems (World, the base Body CS, or the follower Body CS) whose coordinate axes the two vector axes of translation-rotation are oriented with respect to. The defaults are World.

 Restricted Parameters

See Also

Cylindrical, Disassembled Prismatic, Disassembled Revolute, Disassembled Spherical

See Modeling Degrees of Freedom for more on representing DoFs with Disassembled Joints.

See Checking Model Topology and How SimMechanics Software Works for more on closed loops and cutting disassembled joints.

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