simscapeEquation

Convert symbolic expressions toSimscapelanguage equations

Syntax

simscapeEquation(f)

simscapeEquation(LHS,RHS)

Description

simscapeEquation(f)converts the symbolic expressionfto a Simscape™ language equation. This function call converts any derivative with respect to the variabletto the Simscape notationX.der. HereXis the time-dependent variable. In the resulting Simscape equation, the variabletimereplaces all instances of the variabletexcept for derivatives with respect tot.

simscapeEquationconverts expressions with the second and higher-order derivatives to a system of first-order equations, introducing new variables, such asx1,x2, and so on.

example

simscapeEquation(LHS,RHS)returns a Simscape equationLHS == RHS.

Examples

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Convert Expressions toSimscapeEquations

Convert the following expressions to Simscape language equations.

syms t x(t) y(t) phi = diff(x) + 5*y + sin(t); simscapeEquation(phi) simscapeEquation(diff(y),phi)

ans = 'phi == sin(time)+y*5.0+x.der;' ans = 'y.der == sin(time)+y*5.0+x.der;'

Convert ODE toSimscapeEquation

Convert this expression containing the second derivative.

syms x(t) eqn1 = diff(x,2) - diff(x) + sin(t); simscapeEquation(eqn1)

ans = 'x.der == x1; eqn1 == sin(time)-x1+x1.der;'

Convert this expression containing the fourth and second derivatives.

eqn2 = diff(x,4) + diff(x,2) - diff(x) + sin(t); simscapeEquation(eqn2)

ans = 'x.der == x1; x1.der == x2; x2.der == x3; eqn2 == sin(time)-x1+x2+x3.der;'

Tips

The equation section of a Simscape component file supports a limited number of functions. For details and the list of supported functions, see Simscapeequations(Simscape). If a symbolic equation contains functions that are not available in the equation section of a Simscape component file,simscapeEquationcannot convert these equations correctly to Simscape equations. Such expressions do not trigger an error message. Expressions with infinities are prone to invalid conversion.

Version History

Introduced in R2010a