Deriving Equations of Motion for Compound Pendulum with 3 DOF

In summary, to determine the equations of motion for a compound pendulum with 3 degrees of freedom, one must identify the variables involved and use principles of dynamics to derive the equations. The 3 degrees of freedom refer to the two angles at which the pendulum arms are displaced and the angle of rotation of the pendulum bob. Deriving these equations allows us to mathematically describe the motion of the pendulum and understand its behavior, which is important in various applications. Common assumptions when deriving these equations include neglecting air resistance and assuming rigid pendulum arms and a point mass bob. While in most cases the equations cannot be solved analytically and require numerical methods, there are some cases where they can be simplified and solved analyt
  • #1
msntito
5
0
Can anyone help?
I have to derive eq of motion of a compound pendulum with 3 rotational dof.
I know how to do it, for simple pendulum (using Lagrangian's).
 
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  • #2
Is it literally a 3d (or conical) pendulum, or a 2d (plane) pendulum made of 3 rods, each with tied to the other by a junction point (thus with 3 degrees of freedom) ?
 
  • #3
It is a single body (irregular shape with an Inertia tensor 3x3), fixed at a point, say O and can move in 3d rectangular coord system (3 rotational DOF...say alpha beta gamma).
 

1. How do you determine the equations of motion for a compound pendulum with 3 degrees of freedom?

To determine the equations of motion for a compound pendulum with 3 degrees of freedom, you first need to identify the variables involved, such as the lengths of the pendulum arms, the mass of the pendulum bob, and the angles at which the pendulum arms are displaced. Then, you can use principles of dynamics, such as Newton's laws, to derive the equations of motion that describe the motion of the pendulum.

2. What are the 3 degrees of freedom in a compound pendulum?

The 3 degrees of freedom in a compound pendulum refer to the three independent variables that can describe its motion. These are the two angles at which the pendulum arms are displaced and the angle of rotation of the pendulum bob.

3. Why is it important to derive equations of motion for a compound pendulum with 3 DOF?

Deriving equations of motion for a compound pendulum with 3 degrees of freedom allows us to mathematically describe the motion of the pendulum and understand its behavior. This is important in applications such as designing pendulum-based instruments, analyzing pendulum systems in engineering, and studying the dynamics of pendulum motion in physics.

4. What assumptions are typically made when deriving equations of motion for a compound pendulum with 3 DOF?

When deriving equations of motion for a compound pendulum with 3 degrees of freedom, some common assumptions include neglecting air resistance, assuming the pendulum arms are rigid, and assuming the pendulum bob is a point mass.

5. Can the equations of motion for a compound pendulum with 3 DOF be simplified or solved analytically?

In most cases, the equations of motion for a compound pendulum with 3 degrees of freedom cannot be solved analytically and require numerical methods for solution. However, in some special cases where certain simplifying assumptions are made, the equations may be solvable analytically.

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