The SISO Calculator app by Deft Dynamics is available for free on the iOS App Store. We built this app so that any engineer can gain an intuitive sense for System Dynamics and Controls. Education is always evolving to become more effective. Sometimes, teaching methods develop painfully slowly. This is especially true in technical arts – it took over two hundred years for universities to learn to teach Newton’s laws based on free-body diagrams. With Dynamics and Controls science brought to life only in the 1930s, today is still an experimental time to decide how best to teach it.
Application of Dynamics and Controls is tightly tied to computing. While hand-sketched Bode and Root Locus diagrams are impressive, they are a slow way to iterate and get a sense of how time and frequency domains interact. By creating a tool that is powerful enough to help practicing controls engineers, but clear enough to be used by engineering students, we hope this app helps simplify the art of Controls design so that it will soon become as familiar among engineers as the free-body diagram. We know that Controls is difficult but we promise it can be rewarding once mastered. Just remember: It’s easy once it’s easy!
All models are stored as ([zeros], [poles], gain), and converted to/from transfer function polynomials or state space models as needed. Matrix and Polynomial math is custom. Roots are calculated (e.g. for Root Locus or Closed Loop solutions) by converting a transfer function to Companion matrix then solving for Eigenvalues using LAPack (Swift Accelerate). Time response is simulated by a state space model representation, discretized using Van Loan’s trick. A range of test models have been verified against commercial software tools and unit tests are used to verify performance before each new release. It is our objective that this tool be accurate and useful so please report any discrepancies you find.
This app was written in iOS Swift for iPhone, iPad, and Mac.
