SimMechanics™

Spherical-Spherical

Represent composite joint composed of two spherical primitives spatially separated by massless connector of constant length

Library

Joints/Massless Connectors

Description

The Spherical-Spherical block represents a composite joint composed of two spherical joint primitives. The Body coordinate system (CSs) on either side of the Joint are connected to the spherical primitives. The primitives are separated spatially by a vector of constant length but variable direction connecting the two Body CS origins. Both primitives are assembled.

The distance separation between the two axes is computed automatically from the Body CS origins to which the Joint is connected. This distance separation (the magnitude of the vector between the Body CS origins) remains fixed at its initial value during the simulation. This initial value must be nonzero.

You cannot connect an Actuator or Sensor to a Massless Connector.

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 directions of the joint axes.

Massless Connector Between Spherical and Spherical Joints

Dialog Box and Parameters

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

Connection Parameters

The base (B)-follower (F) Body sequence determines the sense of positive motion. Positive rotation is the base or follower pivoting as shown by the motion figure in the Spherical block reference page.

Current base: When you connect the base (B) connector port on the Spherical-Spherical 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, Spherical-Spherical Base and Follower Body Connector Ports.
Current follower: When you connect the follower (F) connector port on the Spherical-Spherical 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, Spherical-Spherical Base and Follower Body Connector Ports.

Spherical-Spherical Base and Follower Body Connector Ports

Parameters

Toggle between the Axes and Advanced panels with the tabs.

The entries on the Axes pane are automatic. They specify the orientation of the spherical DoFs that the Spherical-Spherical represents.

Name: This column automatically displays the name of each primitive joint contained in the Joint block. For Spherical-Spherical, there are two spherical primitives, labeled S1 and S2, connecting to base and follower, respectively.
Primitive: This column automatically displays the type of each primitive joint contained in the Joint block. For Spherical-Spherical, there is only one primitive type, labeled Spherical.
Axis of Action [x y z]: These fields are not active.
Reference CS: These fields are not active.

The Advanced pane is optional. You use it to control the way SimMechanics™ simulation interprets the topology of your schematic diagram.

Mark as the preferred cut joint

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.