You Can’t Prototype This: The Power of Mechatronic Design

Yesterday I took the family to the airport for their semiannual flight back to the UK to visit friends and family.  And as I watched the luggage go down the conveyor belt I started to wonder what went on behind those black plastic doors.  Now we’ve all heard of stories where you fly to Madrid but your luggage ends up in Beijing, but have you ever thought of what happens in such an automated system?  From a systems point of view, it’s just one giant mechatronic sorting machine, but from a design point of view it’s a machine that you cannot prototype.  It’s a one-off–it’s large and expensive, and any issues you have with it could well only turn up at the time of installation.

If you have a one-off design the importance and impact of design analysis and verification becomes even greater.  The cost of redesign is huge at the time of installation, but the delay in putting your product into service can also have a dramatic impact on cost.  So thinking back to my baggage sorting machine at the airport, how would I design and test this inside SolidWorks?  Well as I said the sorting machine is a mechatronic design where the mechanical, control and electrical aspects of design are closely coupled.  If one aspect of the mechatronic design doesn’t work then the machine fails, you need to test each aspect of the design before you build. 

Let’s consider the small conveyor system below.  A product, in this case a pallet with two engine cylinder blocks, moves down one conveyor and then is lifted onto the second shorter conveyor (the image showing the end of the simulation).  We can build this simple behavior with Event Based Motion (the lower part of the image).  In event based motion analysis, sensors trigger action in the same way that a light beam or micro switch sensor would in the real world, allowing the designer to try different sensor locations. Once the sensor locations are set routing can then be used to layout the cable runs thoughout the conveyor.

  Conveyer

But what about the controls design?  Well, as a result of the event based approach, one of the outputs is a Gant chart of the event interactions (bottom right of the image).  This is the first part of the controls design, but you can go so much further by using either Motion Analyzer from Rockwell Automation or LabView from National Instruments.  These partner products allow you to control your machine using virtual controls software so you can create a true virtual prototype of your machine.

Just as important as the motion verification is the stress analysis–you want to make sure that your machine can withstand the operational loads.  So with the event based motion analysis calculated, you can transfer the motion loads to structural simulation and evaluate stresses and displacements to ensure that there is an adequate factor of safety. If the factor of safety is too high, then parts can be redesigned, the motion analysis re-run and the stresses re-calculated.  SolidWorks Simulation can then go one step further and calculate the expected service life of the components, helping the design team set the correct maintenance schedule.

Simparts

With SolidWorks and its partners a true mechatronic design approach is possible.  The three aspects of modern machine design, mechanical, electrical and controls, are brought together inside of SolidWorks allowing a holistic approach to machine design.  When you cannot prototype, developing a true lifelike virtual design is central to minimizing the risk of design.  Simulation gives the designer information to make better design decisions, and ultimately better products.

Stephen Endersby

Stephen Endersby

Product Manager at SolidWorks