Related to calculate average within particular range of graph

Hello,

I am new to matlab. I got signals from the sensors for force with respect to time. The values of time and force are stored in respetive columns after importing it in matlab through excel file. Thus, I need to find the average values within particular range of values in graph (highlighted in red colour). Can someone help?

Thanks

Preshit

Answer 1

[Star Strider]

Use the negative of your signal (essentially flipping it upside-down) so the sharp dips are now peaks. Then use either findpeaks or islocalmax to isolate the indices of the peaks. Use those indices to calculate the mean between them. (If I had your signal, I could write code specific to your problem. With only a picture, I can only describe the approach.)

[Preshit Limje]

Thanks for your suggestion. I was only able to write this:

clear all;

close all;

clc

[num,txt,raw]=xlsread('test 1');

time=num(:,1);

Fz=num(:,5);

Mz=num(:,7);

plot(time,Fz);

I will try to do my best but it will be a great pleasure if you will help me with this. Here is the excel file.

Thanks.

[Star Strider]

This was slightly more complicated than I originally thought it would be.

The Code —

[num,txt] = xlsread('test 1.xlsx');
time=num(:,1);
Fz=num(:,5);
Fzei = find(Fz > 270);                                          % Edit ‘Fz’ To Eliminate Irrelevant Data
[pks,locs] = findpeaks(-Fz(Fzei), 'MinPeakProminence',100);     % Find Sharp Dip Indices
locsi = Fzei(locs);                                             % Map ‘lods’ To Edited Data Indices

for k = 1:numel(locsi)-1
    idxrng{k} = (locsi(k)+1):(locsi(k+1)-1);
    seg_mean(k) = mean(Fz(idxrng{k}));
end

figure
plot(time,Fz);
hold all
plot(time(locsi), -pks, 'vr')
for k = 1:numel(idxrng)
    plot(time(idxrng{k}), ones(size(idxrng{k}))*seg_mean(k), '-r', 'LineWidth',2)
end
hold off
grid
xlabel('Time')
ylabel('F_z')
legend('Data','Valleys','Segment Mean', 'Location', 'NW')

The Plot —

This appears to give the requestted information. The segment means are in the ‘seg_mean’ vector. Experiment to get other results.

[Preshit Limje]

Hello Strider,

Thanks a lot. I much appreciate your help for solving this problem.

[Star Strider]

As always, my pleasure!