Diffedge

Diffedge is a new methodology that eliminates the drawbacks of finite-difference approximations and the complexity to use the automatic differentiation. It combines the powerful of computer algebra system and block diagram structures for computing the derivative of a Simulink™ model with respect to the independent parameters. Diffedge calculates the symbolic derivative of the mathematical models described in the form of block diagram by the application of JM's rules. The obtained symbolic derivative is also represented in graphic form (block diagrams) and can be used like any Simulink® model. The benefits for the user are numerous. We remain in the Simulink™ environment.  Diffedge does not require any task of programming and modification of the model. The visualisation of the partial derivatives is possible for any coordinates of the model. This presentation  illustrates the capabilities of Diffedge , its implementation in the Matlab™ environment and some applications.

When Diffedge has to be used ? : In this situations

• Model with noise blocks.
• Data with noise (optimisation with hardware in the loop).
• Model highly non-linear dynamic ( tanh, sin, exp, ..).
• Model discontinuities or events.
• Large model with numerous parameters ( Diffedge sorts parameters by maximum action into the model)
• Statistic calibrating and validating structure or parameters.
• Identification look-up table ( 1D and 2D).
• Choose precisely the best zone in the output signals for computing the objective function.
• The optimization routine does not converge with numerical gradient.
• Sensitivity analysis with respect to parameters and initial conditions.
• Save time in analysis or optimization of your model ( diffedge is an automatic tools).
• Thrust about values of parameter obtained after an optimization or identification.
• embedded derivative code ( in simulink or real time).
• Optimisation with variable step solver.
• .... To be successful in our optimization of simulink models.

™®Matlab/simulink and optimization, symbolic toolboxes are registered trademarks of The Mathworks, Inc

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