Callback function not able to update System

I am implementing a slider for a certain variable in a spring-damper system and trying to update the plot according to the value in the slider using the callback fn. but somehow not able to update it.

clc
clear 
close all
m = 8              %mass
k = 1          %stiffness
c = 0.5           %damping
time = 0 : 0.1 : 10;
t = sym ('t')
x_0= 0.01;                % Initial Condition displacement
x_dot_0= 0;               % Initial Condition velocity


syms x(t)

Dx = diff(x,1);
D2x = diff(x,2);
x = dsolve( m*D2x + c*Dx + k*x == 0  ,x(0)==x_0  ,Dx(0) == x_dot_0,  't');  % Initial conditions units are [m] and [m/s] respectively
x_fun = matlabFunction(x);
sys = x_fun(time);
f = figure;
ax = axes('Parent',f,'position',[0.13 0.42  0.77 0.54]);
h1 = plot(time,sys);

bgcolor = f.Color;
b = uicontrol('Parent',f,'Style','slider','Position',...
    [81,130,419,23],'value',c, 'min',0, 'max',5);
bl3 = uicontrol('Parent',f,'Style','text','Position',[240,115,100,23],...
     'String','Damping Ratio','BackgroundColor',bgcolor);
bl1 = uicontrol('Parent',f,'Style','text','Position',[50,130,23,23],...
                'String','0','BackgroundColor',bgcolor);
bl2 = uicontrol('Parent',f,'Style','text','Position',[500,130,23,23],...
                'String','5','BackgroundColor',bgcolor);
b.Callback = @(es,ed) updateSystem(h1,dsolve(m*D2x + c*Dx + (es.Value) *x == 0  ,x(0)==x_0  ,Dx(0) == x_dot_0,  't'));

Answer 1

[Rik]

I prefer to use actual functions for my GUIs, see if this helps. Usually this also really helps with debugging.

m = 8;              %mass
k = 1;          %stiffness
c = 0.5;           %damping
time = 0 : 0.1 : 10;
t = sym ('t');
x_0= 0.01;                % Initial Condition displacement
x_dot_0= 0;               % Initial Condition velocity


syms x(t)

Dx = diff(x,1);
D2x = diff(x,2);
x = dsolve( m*D2x + c*Dx + k*x == 0  ,x(0)==x_0  ,Dx(0) == x_dot_0,  't');  % Initial conditions units are [m] and [m/s] respectively
x_fun = matlabFunction(x);
sys = x_fun(time);
f = figure(1);clf(f)
ax = axes('Parent',f,'position',[0.13 0.42  0.77 0.54]);
h1 = plot(time,sys);

bgcolor = f.Color;
b = uicontrol('Parent',f,'Style','slider','Position',...
    [81,130,419,23],'value',c, 'min',0, 'max',5,...
    'Callback',@callback_wrapper);

bl3 = uicontrol('Parent',f,'Style','text','Position',[240,115,100,23],...
    'String','Damping Ratio','BackgroundColor',bgcolor);
bl1 = uicontrol('Parent',f,'Style','text','Position',[50,130,23,23],...
    'String','0','BackgroundColor',bgcolor);
bl2 = uicontrol('Parent',f,'Style','text','Position',[500,130,23,23],...
    'String','5','BackgroundColor',bgcolor);

handles=struct;
[handles.f,handles.h1]=deal(f,h1);
vars=struct;
[vars.m,vars.c,vars.x_0,vars.x_dot_0,vars.x,vars.Dx,vars.D2x]=deal(...
    m,c,x_0,x_dot_0,x,Dx,D2x);
handles.vars=vars;
guidata(handles.f,handles)

function callback_wrapper(es,ed)
handles=guidata(es);vars=handles.vars;
[m,c,x_0,x_dot_0]=deal(...
    vars.m,vars.c,vars.x_0,vars.x_dot_0);
k=es.Value;
syms x(t)
Dx = diff(x,1);
D2x = diff(x,2);
sys=dsolve(m*D2x + c*Dx + k*x == 0  ,x(0)==x_0  ,Dx(0) == x_dot_0,  't');
updateSystem(handles.h1,sys)
end

[Abdelrahman Darwish]

I tried your code but nothing changed, I keep trying to move the slider but the plot is not affected.

The following error is generated:

Undefined function or variable 'updateSystem'.

Error in LiveEditorEvaluationHelperE975945502>callback_wrapper (line 43)

updateSystem(handles.h1,sys)

Error while evaluating UIControl Callback.

>>

[Rik]

Does that function work when using it in isolation?