Equations to Matlab code

hi

I want to convert the two equations below into Matlab code , I wrote the function below for that and I don't know if that is correct or not , specially the integral form ? any help ?

    function [VI,Vw]= Modelfun(TL,TR)

    dt=0.01; %sampling time
    r=0.052;
    L=0.306;
    M=9;
    I=5;
    VI=(TL+TR)/ M * r;
    VI=VI*dt/2; %first integral

    Vw=(L*(TL-TR)) / 2 * r * I;
    Vw=Vw*dt/2; %first integral
    Vw=Vw*dt/2; %second integral

    end

Answer 1

[Torsten]

It is not possible simply to output (VI,Vw) given (TL,TR).

As input you need (VIold,Vwold,Vwdotold,dt,TL,TR).

The output VI,Vw and Vwdot is then calculated according to

VI=VIold+dt*(TL+TR)/(M*r)

Vw=Vwold+dt*Vwdotold

Vwdot=Vwdotold+dt*L*(TL-TR)/(2*r*I).

This would mean that your function "Modelfun" advances VI and Vw from their values at time t to time t+dt.

Best wishes

Torsten.

Answer 2

[Torsten]

If the right-hand sides of your equations does not depend on t, the solution to your differential equations is explicitely given by

VI=VI0+(TL+TR)/(M*r)*t

Vw=Vw0+Vw0dot*t+0.5*L*(TL-TR)/(2*r*I)*t^2

where

VI0=VI at time t=0

Vw0=Vw at time t=0

Vw0dot = d/dt(Vw) at time t=0.

Best wishes

Torsten.

[Maria]

thanks a lot but please could you explain how and why did you that ?

hint : the equations are for dynamic model of mobile robot

[Maria]

Any help ? please

[Torsten]

What is your function "Modelfun" supposed to do ?

Should it calculate VI(t+dt) and Vw(t+dt) given the values VI(t) and Vw(t) ?

Best wishes

Torsten.

[Maria]

thanks a lot Torsten

Actually , I am not so good with Matlab and from my little bit understanding I built this function and I don't know if that right but generally what I want to do is to write the equations above in code form inside "Embedded MATLAB Function " block with two inputs(TL,TR) and two outputs (VI,Vw) as in figure above.

thanks

[Maria]

???

Answer 3

[Warren Dennis]

k=k0e