Equations of motion for a compound pendulum

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SUMMARY

The discussion focuses on deriving the equations of motion for a compound pendulum, characterized by parameters such as mass (M), mass moment of inertia (Ixx, Iyy, Izz, Ixy, Iyz, Izx), and Euler angles (theta, phi, psi) along with their time derivatives (theta_dot, phi_dot, psi_dot). The kinetic energy is defined as T = 0.5 * ω * I * ω, while the potential energy is given by V = -m * g * z. The Lagrangian is expressed as L = T - V. The user has successfully derived the center-of-mass coordinates in terms of Euler angles and seeks assistance in deriving the angular velocity components.

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  • Knowledge of kinetic and potential energy formulations
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Homework Statement


To derive the equations of motion for a compound pendulum. Pendulum parameters are: mass M, mass moment of inertia= Ixx,Iyy,Izz,Ixy,Iyz,Izx, Euler angles theta, phi & psi and their time-derivatives theta_dot, phi_dot, & psi_dot, and coordinates of center-of-mass (x,y,z)

The coordinate system is give as; X & Y axis in horizontal plane, while Z axis point downwards. (SEE FIGURE attached with this post)
https://www.physicsforums.com/attachment.php?attachmentid=27054&stc=1&d=1279608886

Homework Equations


Kinetic energy, T = 0.5 \omega * I * \omega
Potential energy, V = -m*g*z
Lagrangian, L = T - V

The Attempt at a Solution


I have found the expression of c-o-m in terms of Euler angles:
x = l*sin(theta)*cos(psi)
y = l*sin(theta)*sin(psi)
z = l*cos(theta)
where, l is the distance between hinge point and c-o-m, and theta is inclination from Z axis, psi is angle between "l*sin(theta)" and X axis.

Now, need to derive the expression for components of angular velocity in terms of Euler angles. How should I do that? Please help.
 
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