Error using ode45 for spring pendulum

2020 4 3
0 个回答
更新时间：2020 4 4
7 次查看（30 天）

0 个投票

Hello there, I was developing an example for class of a spring pendulum that was to utilize the ode45 command on MATLAB. Problem is, that somehow the ode45 keep encountering errors and I can't seem to figure out why this is the case. Anyone have any insight?

3 个评论
显示 1更早的评论 隐藏 1更早的评论

madhan ravi
madhan ravi 2020-4-3
编辑：madhan ravi 2020-4-3
Could you paste the code(not as a file)?
Mathew Amador
Mathew Amador 2020-4-4
编辑：Mathew Amador 2020-4-4
"Solve for the EOMs of a spring pendulum system, then integrate the EOM for 10 seconds starting at rest with the radial position at and . The spring is unstretched at . Then, integrate the EOM for 120 seconds starting at rest with a variety of initial conditions with in meters and in degrees."
Goal: Plot the initial position of the mass using a blue line with 'x' markers and the final position of the mass using a black line with 'x' markers.
Step 1:
clear variables
clc
m = 0.1416; % kg
k = 7.1; % N/m
g = 9.81; % m/s^2
r_0 = 9; % cm
r = 29; % cm
theta = 30; %degrees
Step 2:
List variables:
m: mass,
k: spring constant,
r: radius,
r_0 : unstretched radius,
theta : Initial angular displacement,
g: gravity,
r_m: linear displacement of mass in the r-direction, state variable
r_mddot: accelerations (EOMs) of the mass in the r-direction
theta_m: displacement of mass in the -direction, state variable
theta_mddot: accelerations (EOMs) of the mass in the -direction
Step 3:
syms m l r
syms thetadot thetaddot rdot rddot
eqn(1) = m*thetaddot == m*((l+r)*thetaddot+2*rdot*thetadot);
eqn(2) = m*rddot == m*(rddot-(l+r)*thetadot^2);
Step 4:
Find Unknown variables
theta double dot, and r double dot : accelerations in the theta and r directions, respectively
2 equations, 2 unknowns
Step 5:
unknowns = solve(eqn, rddot, thetaddot)
accelEOMs = solve(eqn,rddot,thetaddot);
accelEOMs = struct2cell(accelEOMs);
Step 6:
Solve equation of motion (EOM)
[T,S] = ode45(@(t,s)eom(m, k, r, r_0, theta, g),linspace(0,10,100),[0,0]);
darova
darova 2020-4-4
Something is wrong

请先登录，再进行评论。

请先登录，再回答此问题。

回答（0 个）

类别

在 帮助中心 和 File Exchange 中查找有关 Assembly 的更多信息

产品

版本

R2020a

标签

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by