How to set maximum and minimum limit of signal in MATLAB code.

I need to set maximum and minimum value of variables. For example,

x3= x1 + x2

where

maximum value of x1 = 3

minimum value of x1 = 0

maximum value of x2 = 2.5

minimum value of x2 = -1

I didn't understand that how i can implement it in MATLAB codes.

Answer 1

[Omer Yasin Birey]

Hi Usman, you can use one of the codes below. However, I recommend the first one, because no loop is necessary here.

x1Max = 3;
x1Min = 0;
x2Max = 2.5;
x2Min = -1;
x1(x1>x1Max) = x1Max;
x1(x1<x1Min) = x1Min;
x2(x2>x2Max) = x2Max;
x2(x2<x2Min) = x2Min;
x3 = x1 + x2;

or

x1Max = 3;
x1Min = 0;
x2Max = 2.5;
x2Min = -1;
x3 = zeros(length(x1),1);
for i = 1:length(x1)%or length x2 since they must have the same dimensions. 
    if x1(i)>x1Max
        x1(i) =  x1Max;
    elseif x1(i)<x1Min
        x1(i) = x1Min;
    end 
    if x2(i)>x2Max
        x2(i) =  x2Max;
    elseif x2(i)<x2Min
        x2(i) = x2Min;
    end
    x3(i) = x1(i)+x2(i);
end

[Usman Taya]

Thanks Brother for answer. But when i have length of x is 12 and try to give data to GA in vector form. is it correct if i write as following:

x(3)(i) = x(1)(i)+x(2)(i)

if it is not correct than please suggest me correct way brother Omer.

[Omer Yasin Birey]

Hi brother, from your comment I understood that you have just one x vector and you want to fill its third index with the sum of the prior first two indexes and it goes on?

If it is correct writing x(3) will be enough to set third data, in Matlab, for array vectors you cannot use double indexing i.e x(3)(i). By the way Im very sorry but I don't know what GA stands for is it google analytics? Or do you want to multiply them like in geometric algebra(GA)?

[Omer Yasin Birey]

x1 = randi(10,1,12);%created 3 x values to test
x2 = randi(10,1,12);
x3 = zeros(1,12);
x1Max = 3;
x1Min = 0;
x2Max = 2.5;
x2Min = -1;
x1(x1>x1Max) = x1Max;
x1(x1<x1Min) = x1Min;
x2(x2>x2Max) = x2Max;
x2(x2<x2Min) = x2Min;
X = cell(3,1);
X{1,1} = x1;
X{2,1} = x2;
X{3,1} = x3;

for i = 1:length(x1)
    X{3,1}(i) = X{1,1}(i) +  X{2,1}(i);
end
x3 = X{3,1}(:);
    

I collected the all x values in a greater X cell which contains x1,x2,x3 and if you call x3 with this way it will be a 12x1 vector.

[Usman Taya]

x1Max = 3;
x1Min = 0;
x2Max = 2.5;
x2Min = -1;
x1(x1>x1Max) = x1Max;
x1(x1<x1Min) = x1Min;
x2(x2>x2Max) = x2Max;
x2(x2<x2Min) = x2Min;
x3 = x1 + x2;

When I used above codes than it shows following error:

Undefined function or variable 'x1'.

Error in Untitled2 (line 5)
x1(x1>x1Max) = x1Max;
Please help to solve the error.

[Omer Yasin Birey]

Hi Usman, apparently you haven't assigned any value to x1. It is hard to understand from here what it should have been given to x1, x2 or x3. Is there any text you can share that explains what code should do? So I can understand fully and help.

[Usman Taya]

Here is my actual code Brother:

x4 = [0,0,0,0,0,0,0,0,0,0,20.10,386.22,1013.36,1688.74,2685.19,2905.13,3370.94,3730.35, 2232.83,4166.60,4404.63,4853.86,4953.58,3897.27,2996.94,4328.13,4293.91,3655.74,3593.10,3080.08,2633.71,2058.05,1374.24,697.60,213.83,41.52,0,0,0,0,0,0,0,0,0,0,0,0];
x5 = [3498.91,3506.20,3491.12,3515.54,3490.08,3546.83,3491.12,3631.95,3895.54,3647.16,3498.37,3548.29,3525.54,3415.20,3394.50,3426.41,3413.20,3409.79,6531.87,6317.20,6433.33,6075.83,5983.62,5525.04,5650,5276.16,5885.04,5169.33,5908.37,5376.66,5733.37,5243.58,5792,5384.25,5408.95,5408.66,3662.29,3701.54,3688.41,3648.87,3648.58,3594.5,3521.12,3653.87,3771.70,3767.20,3541.04,3532.16];
E_batt_inst = 80000;
x3Max = 72000;
x3Min = 8000;
x2Min = -5000;
x2Max = 5000;
x1Min = 0;
x1 = zeros(48,1);
x2 = zeros(48,1);
x3 = zeros(48,1);
for i = 1:48
    if i<14 && i>40
        x1Max = 4500;
    elseif i>14 && i<=40
        x1Max = 3000;
    end
    if i==1
        x3 = 40000;
        flag = 1;
    end
    if x1(i)>x1Max
        x1(i) =  x1Max;
    elseif x1(i)<x1Min
        x1(i) = x1Min;
    end
    if x2(i)>x2Max
        x2(i) =  x2Max;
    elseif x2(i)<x2Min
        x2(i) = x2Min;
    end
    if x3(i)>x3Max
        x3(i) =  x3Max;
    elseif x3(i)<x3Min
        x3(i) = x3Min;
    end
    if (flag == 1)&&(x3 <= 8000)
        x2(i)=  x5(i) - x4(i)
    elseif x2(i)< x5(i) - x4(i)
        x1(i)=  x5(i) - x4(i) - x2(i)
        t = i-1;
        x3(i) = x3(t) - (x2(i)/E_batt_inst);
        flag = 1;
    elseif (x3 >= 72000)
        flag = 0;
        x2(i)=  x5(i) - x4(i)
    elseif x2(i)< x5(i) - x4(i)
        x1(i)=  x5(i) - x4(i) - x2(i)
        t = i-1;
        x3(i) = x3(t) - (x2(i)/E_batt_inst);
    end
end

Here x1, x2 and x3 is measured by given equation. x2 is power of battery which is charging and dischargine with respect to maximum and minimum capacity (x3) of battery. x1 is power imported from diesel generator. Battery is not allowed to discharge when its charged and flag = 1. When charging than battery power is in negative (-5000 (x2Min)) while discharge it is positive (5000 (x2Max)). If you want further details than please share your email address so I can email u. or please send me email on [e-mail]