Recent content by Remusco

  1. Remusco

    A Flaw in Lagrangian Mechanics for a rotary inverted pendulum system? (Simulation vs. Measured)

    All I'm trying to do is replicate this YouTube tutorial, but for a uniform pendulum rod, not a point mass...
  2. Remusco

    A Flaw in Lagrangian Mechanics for a rotary inverted pendulum system? (Simulation vs. Measured)

    The physical model result is from my physical rotary inverted pendulum. It is the data I collected with my Arduino. The simulated as shown in the plot is the result from the Newtonian equations. Here I now solve the Newtonian equations for theta_ddot:
  3. Remusco

    A Flaw in Lagrangian Mechanics for a rotary inverted pendulum system? (Simulation vs. Measured)

    Here are the Newton's equations: $$ -T \sin{\left(\theta \right)} - b \theta_{dot} \cos{\left(\theta \right)} - m_{p} x_{ddot} - \frac{1}{2} L m_{p} \cos{\left(\theta \right)} \theta_{ddot} + \frac{1}{2} L m_{p} \theta_{dot}^{2} \sin{\left(\theta \right)} = 0$$ $$-T \cos{\left(\theta \right)} -...
  4. Remusco

    A Flaw in Lagrangian Mechanics for a rotary inverted pendulum system? (Simulation vs. Measured)

    I'm directly controlling phi with my stepper motor. The position, velocity, acceleration. The dynamics of phi are whatever I want them to be, and I'm assuming that the stepper is rigid and does not slow down under changes in torque, which is a valid assumption. This reduces the DOF by one...
  5. Remusco

    A Flaw in Lagrangian Mechanics for a rotary inverted pendulum system? (Simulation vs. Measured)

    Thanks for sending that to me. Great resource. However, I used the exact results in the paper and this is what i get. Still the same thing is happening: import sympy as sp # === Step 1: Define all symbolic variables === theta1, theta2 = sp.symbols('theta1 theta2') theta1_dot, theta2_dot =...
  6. Remusco

    A Flaw in Lagrangian Mechanics for a rotary inverted pendulum system? (Simulation vs. Measured)

    I have built this inverted pendulum system (powered by a stepper motor). I define theta to be the pendulum angle 0 degrees in the vertical position, phi is the motor arm angle. When I let the physical pendulum go at theta = 90 degrees, with the stepper motor turned off, I get: Now if I...
  7. Remusco

    Computing the moment of inertia for a rotary inverted pendulum

    Yes this is what I am looking for. Thanks for clarifying.
  8. Remusco

    Computing the moment of inertia for a rotary inverted pendulum

    I looked all over the internet and I can't find a derivation of this. It is over my head to derive this. This is my system: I want to assume that the pendulum and motor arm are uniform rods. I want to ignore the motor shaft inertia and the rotary encoder inertia since they are negligible. Does...
  9. Remusco

    Simulating a Rotary Inverted Pendulum in Python

    No, I wrote all of this myself. The only thing I'm not sure about are the inertias.
  10. Remusco

    Simulating a Rotary Inverted Pendulum in Python

    # System Parameters m_p = 0.1 # Mass of pendulum (kg) m_a = 0.5 # Mass of arm (kg) l_p = 0.2 # Length of pendulum (m) l_a = 0.15 # Length of arm (m) g = 9.81 # Gravity (m/s^2) b = 0.00 # Damping coefficient I_a = (1/3) * m_a * l_a**2 # Arm moment of inertia I_p = (1/3) * m_p *...
  11. Remusco

    Simulating a Rotary Inverted Pendulum in Python

    I am getting really good results now with this code: import numpy as np import matplotlib.pyplot as plt # System Parameters m_p = 0.1 # Mass of pendulum (kg) m_c = 0.5 # Mass of arm (kg) l_p = 0.2 # Length of pendulum (m) l_a = 0.15 # Length of arm (m) g = 9.81 # Gravity (m/s^2) b =...
  12. Remusco

    Simulating a Rotary Inverted Pendulum in Python

    I need help calculating inertias for a rotary inverted pendulum system (Furuta pendulum). This is for a school project. The pendulum is a unform rod, and the motor arm is a unform rod. The equations of motion are: Where theta is the angle of the pendulum (0 degrees is in vertical position)...
  13. Remusco

    Simulating a Rotary Inverted Pendulum in Python

    Do you think my calculation for the inertia seen by the motor shaft is correct? Isn't this just J_p or should this be J_p + m_p*r_a**2?
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