Double pendulum equations of motion

[Daniel1992]

Hi,

I am trying to create displacement time series graphs of a double bar pendulum using Matlab.

Am I correct in assuming that if I use the ode45 solver to integrate the equations below I can plot displacement time series graphs? Are these the correct coupled first order ODEs to use?

Source of above equations

Thanks,
Daniel

 

[lippyka]

Yes, you are correct in assuming that if you use the ode45 solver to integrate the equations below (which are the correct coupled first order ODEs for a double bar pendulum) you can plot displacement time series graphs. The equations you have provided are: d2θ1/dt2= (-g/l1)*sin(θ1) - (b/m1) * dθ1/dt + (1/m1) * (F(t) – 2*F(t)*cos(θ2-θ1))d2θ2/dt2 = (-g/l2)*sin(θ2) - (b/m2) * dθ2/dt + (1/m2) * (F(t) – F(t)*cos(θ2-θ1))Where: θ1 : angle of first pendulumθ2 : angle of second pendulumg : acceleration due to gravityl1 : length of first penduluml2 : length of second pendulumm1 : mass of first pendulumm2 : mass of second pendulumb : coefficient of dampingF(t) : driving forceYou can use these equations with the ode45 solver to calculate the displacement time series graphs.