This document describes major bug fixes for SimMechanics 2.2. Click on a problem area listed below to read how it has been fixed.
Bodies Now Require At Least One Non-CG Body Coordinate System
Body Coordinate System References Restricted and Correctly Resolved
CAD Translator Computed Joint Locations Bug Fixed
CAD Translator Error with Joint Axis Placement Fixed
Constraint Warning in Lower Dimensional Machines
import_physmod Error with Certain File Names Fixed
mech_StateVectorMgr Overwriting gcs Return Value Bug Fixed
Model Reference Supported with SimMechanics
Point-Curve Constraint GUI No Longer Errors When Deleting a Spline Point
Sample Time Colors Now Work with SimMechanics Upon Update Diagram
Trimming Mode with Joint Initial Condition Actuators Now Works
Update Diagram After Simulation Error Fixed
In previous versions of SimMechanics, you could eliminate all regular Body coordinate systems (CS1, CS2, etc.) in the Body dialog, leaving only the center of gravity CS (CG CS), which cannot be deleted. Eliminating all regular Body CSs created model saving, updating, and visualization errors. You can now only eliminate all but one of the regular Body CSs. A Body thus never has fewer than two CSs, including the center of gravity.
All references from one Body coordinate system (CS) to other CSs in the model must now refer only to CSs on the same Body, to Adjoining CSs (coordinate systems on Bodies directly connected to the referring Body), or to World. Also, some models with correct but complex CS references incorrectly stopped with an error triggered by mutually dependent CS references. SimMechanics now correctly resolves these Body CS references.
The SimMechanics computer-aided design (CAD) translator for SolidWorks sometimes computed joint locations incorrectly if two or more mates between two parts had identical attachment points. This bug is now fixed.
The SimMechanics computer-aided design (CAD) translator for SolidWorks sometimes exported information about joint axes and their associated Body coordinate systems incorrectly. This bug has been fixed.
If you construct a SimMechanics model of a machine initially in one or two dimensions, and all the forces are also in one or two dimensions, the motion should remain in one or two dimensions. But if the model includes a higher dimensional joint, the machine sometimes starts moving in the higher dimension and comes apart. An example is a planar four bar machine connected with universal joints. The machine should move only by rotating about the single axis perpendicular to the plane.SimMechanics now diagnoses whether such an unstable initial configuration could cause a constraint violation and warns you if it can. If a constraint is violated, the simulation still stops with an error.
Avoid this singularity by slightly misaligning the axes, within assembly tolerances.
Previously, when you imported a Physical Modeling XML file representing a computer-aided design (CAD) assembly into SimMechanics, using theimport_physmodcommand, the import failed if the filename had fewer than four characters and you did not include the.xmlfile extension. This bug is now fixed.
After using themech_StateVectorMgrcommand to obtain a SimMechanics system state vector, thegcsvalue for that system would be reset incorrectly. This bug is now fixed.
The "Known Software and Documentation Problems" section of the prerelease SimMechanics 2.2 release notes incorrectly stated that the Model Reference feature of Simulink did not work with SimMechanics. In fact, this feature is supported with SimMechanics.
When you attempted to add, then delete, points on a spline curve in the Point-Curve Constraint interface, SimMechanics would sometimes stop with error. This bug has now been fixed.
If Sample Time Colors is selected in a model's Format > Port/Signal Displays menu, all signal lines are colored in a way that reflects the sample rate of the signal. When you update your diagram in SimMechanics, the sample color of incoming Actuator and outgoing Sensor signal lines is now correctly set to black (continuous and varying in a minor time step), and the model no longer crashes.
The SimMechanics Trimming mode did not correctly initialize the accelerations of degrees of freedom corresponding to joints with Joint Initial Condition Actuators, leading to trimming warnings or errors. The Trimming mode now correctly initializes these accelerations in models with JICA blocks.
If, following a simulation error, you used Update Diagram from the Edit menu, a signal propagation error would result. This bug has now been fixed.
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