Mechatronics

This blog series and the tests reported herein is designed to show some of the key differences between Autodesk Inventor Professional 2011 and SolidWorks Premium 2011 for digital prototyping workflows. This final part of our 8 part blog series examines Mechatronics – the ability to perform cable and harness design in an existing design from an imported electrical wiring diagram.

We test the ability of the mechanical CAD system (MCAD) to leverage data from an electrical CAD system (ECAD). The ECAD system specifies the appropriate connectors, wires, and their connection points while the MCAD system specifies the physical location of those wires and connectors within a product.

Autodesk supplied an Inventor video of their solution, a net list in Excel format, a STEP file of the enclosure assembly, and a schematic drawing (.dwg) of the connections.

What’s Important in Mechatronics Design

• Leverage the data stored in schematic drawing files to design wire harnesses in the mechanical system. Such data can be stored exported from an electrical design file using various techniques. At its most basic, the electrical design software sends a net list to the mechanical package containing connector information for each wire, wire types, and a list of pin-to-pin connections.
• Generate correct wire lengths
• Generate output to enable manufacturing of the wire harness
• Not tested were two-way associativity between the electrical and mechanical software, nor were any tests designed to simulate electromechanical interconnections such as activating switches or sensors based on mechanical actions.

Autodesk supplied us with an Inventor video of their solution, a net list in Excel format, a STEP file of the enclosure assembly, and a schematic drawing (.dwg) of the connections.

What we found out

The two software packages (Inventor and SolidWorks) are comparable. Inventor has a tight connection to AutoCAD Electrical with the xml file transfer. SolidWorks has similar tight coupling with some third party software such as Zuken’s E3. Both systems use added cost electrical software to generate the net-list. SolidWorks was not able to read the AutoCAD Electrical generated xml list, and instead used an Excel file with similar data that needed manual cleanup in Excel.

It appears that there are a few more interactions with SolidWorks, but this may be due to the operator-preferred method. Both systems effectively produced the required output. There appears to be no real operational advantage to either package when used with tightly integrated electrical schematics software. Since AutoCAD Electrical is one of the most widely used electrical schematic packages, the advantage goes to Inventor.

Observations

For this test, on the AutoCAD side, AutoCAD Electrical exports an XML file to Inventor. Inventor reads this file and generates the 3D wiring and, under user control, assigns wires to cables. It can then generates wire lengths, a flat wire harness diagram and a pin board for manufacturing.

Inventor opens the 3D model and then the xml file of the net-list from AutoCAD Electrical. This designates the pin-to-pin connections where the wires are to be placed. Different than SolidWorks, the Inventor user placed the harnesses in anticipation of the wiring to be imported. The wire import could also have been done first, as seen in the SolidWorks video. The names of the connectors and the number of pins on each connector are stored in coordinated libraries in both the electrical and mechanical systems.

After the import, the imported wires appear as direct point-to-point connections between the pins without using any harnesses. 19 wires were imported and identified as un-routed. Then Inventor asks for an auto-route of all un-routed wires. It then places all 19 wires into the predesigned harness, we guess by using closest entry and exit points. Then Inventor builds (and reports) a pin board payout of the harness showing the 3D derived wire lengths. The video below shows an Inventor user performing the test. 

SolidWorks takes a slightly different, albeit very similar approach. After importing the net-list, the operator builds a 3D representation of the harness and then places the wires into the harness, with the software computing the wire lengths. This took more manual interaction than the Inventor solution, but yielded the same end result. The video below shows a SolidWorks user performing the test. 

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This is the final blog in this series. Users can review a summary of these tests, published as Part 1 of this series by clicking here. We have also published a pdf file of the complete report here. The pdf file does not contain any videos. To see them you have to revisit this blog series at raykurland.com.

About the author

Raymond Kurland is president of TechniCom Group LLC and its principal consultant and editor. His firm, founded in 1989, specializes in analyzing MCAD and PLM systems and has been involved in reviewing and comparing such software since 1987. Ray frequently consults with both vendors and users. Ray has degrees in Engineering from Rutgers University and from NYU. His career included stints with Bell Telephone Laboratories, IBM, and Dassault Systemes. Ray can be reached at rayk@technicom.com.

For more information about TechniCom Group and other software reviews please visit http://www.cad‑portal.com and Ray’s blog at www.raykurland.com. You can also follow Ray on twitter using the id technicom.

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