How do i plot x1(t) and x2(t) from a state space model

Hi i think this is fairly easy to do but i am pretty new to boh matlab and system modelling so hopefully you guys can help me, I have constructed a state space model from a system consisting of two water tanks that are connected to each other, x1 is the water level in tank 1, x2 is the water level in tank 2. I want to plot x1 as a function of time as well as x2 as a function of time. My input signal is a step with a amplitude of 0.1, thank you in advance.

syms a g A h10 h20 opt;
a = 0.1;
A = 1;
h10 = 1;
h20 = 1;
g = 9.81;

Am = [-(a*(2*g)^(1/2))/(2*A*(h10^(1/2))) 0; (a*(2*g)^(1/2))/(2*A*(h10^(1/2))) -(a*(2*g)^(1/2))/(2*A*(h20^(1/2)))]
Bm = [1/A ; 0]
Cm = [1 0; 0 1; (a*(2*g)^(1/2))/(2*A*(h10^(1/2))) 0]
Dm = [0; 0; 0]

tank = ss(Am, Bm, Cm, Dm,  'Inputname', 'U', 'Outputname','q2', 'Statename',{'h1(t)', 'h2(t)'})
opt = stepDataOptions;
opt.StepAmplitude = 0.1;

Answer 1

[Ameer Hamza]

See this

a = 0.1;
A = 1;
h10 = 1;
h20 = 1;
g = 9.81;
Am = [-(a*(2*g)^(1/2))/(2*A*(h10^(1/2))) 0; (a*(2*g)^(1/2))/(2*A*(h10^(1/2))) -(a*(2*g)^(1/2))/(2*A*(h20^(1/2)))];
Bm = [1/A ; 0];
Cm = [1 0; 0 1; (a*(2*g)^(1/2))/(2*A*(h10^(1/2))) 0];
Dm = [0; 0; 0];
tank = ss(Am, Bm, Cm, Dm,  'Inputname', 'U', 'Outputname','q2', 'Statename',{'h1(t)', 'h2(t)'});

opt = stepDataOptions('StepAmplitude', 0.1);
step(tank, opt)

Note that your ss model have 3 outputs. First two are x1 and x2. The third is same as you defined in last row of Cm.

[Marcus Eliasson]

Thank you?

[Ameer Hamza]

I am glad to be of help.