how can i do this?

hey guys, i must make a plot like as follows: L=ax. x is constant. a is changing linearly in some intervals so L is changing like that also (in the picture for theta=-180:-120 and 0:60 a is decreasing linearly, -60:0 and 120:180 a is increasing linearly, -120:-60 and 60:120 a is equal to zero). How can i do this there are three parameters: a, L and theta. And L is changing with variation of theta and a.

Answer 1

[Orion]

Hey,

Just do :

% amplitude
Lmaks = 10;

% coordinates vectors
theta = [-180  -120 -60 0     60 120 180];
L     = [Lmaks 0    0   Lmaks 0  0   Lmaks];

% plot
figure('Position',[59   544   756   220]);
plot(theta,L);
axis([-180 180 -5 15]);
xlabel('\theta_m')
ylabel('L_{11}(\theta_m)')
grid

Answer 2

[m]

thanks a lot. I wonder if there is a method like a simulation. for example theta is position of motor and when the motor starts to rotating then L is changing with them is it possible in matlab? i won't do this, i wonder only

[Orion]

Sure, you can do that with something like

time = 0:0.01:5;
MyAngularValue = 2*180/pi*sin(2*pi*time);
MyLvalue = interp1(theta,L,MyAngularValue);
figure;
subplot(211)
plot(time,MyAngularValue,'b')
ylabel('theta')

subplot(212)
plot(time,MyLvalue,'r')
ylabel('L')
xlabel('time')