EOMs for T Shaped Pendulum with Non-Conservative Force

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EOMs for "T" Shaped Pendulum with Non-Conservative Force

I have a set of equations of motion I'm trying to derive. This problem represents a 2-d approximation of the real system that I'm trying to derive equations of motion for modeling purposes.

There is a base mass and a top mass.

The base mass is constrained to move only in the x direction and is connected by a linear spring to ground which is meant to produce forces that restore the mass to the x = 0 position. Friction is ignored.

The top mass designated (the "T" shaped pendulum) can rotate about the point at the center of the base coordinate system. A torsional spring is operating on the pendulum to produce forces that restore it to the vertical position.

I've chosen my generalized coordinates to be x (corresponding to x-base) and theta (rotation of pendulum from horizontal).

I will include my derivations in reply to this post but my main question is whether I did the virtual work properly? Do I need to for any sort of moment-work?
 
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System Figures
 
Attachments
  • Schematic of a T-shaped pendulum on a cart: a rigid bar with mass Ms and inertia Is at height h above a base with mass Mb on rollers, with body frame xB, yB, sensor frame xS, yS, forces FC and RC, offset rcp, angle Theta, torsional spring Kt,S and spring KB.
    TShapedPendulumMovment.png
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  • Geometry diagram of a pendulum of length h at angle Theta from the horizontal, showing body frame axes xB and yB, sensor frame xS and yS, offset Rcp, center vector RC, and force FC with components Fc,x and Fc,y.
    TShapedPendulumMovment_Vectors.png
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Pages 1 through 3
 
Attachments
  • Handwritten-style derivation of kinetic and potential energy for a pendulum system: generalized coordinates x and theta, base and top mass kinetic energies, velocity components, expanded and simplified equations (1) through (11).
    2DStrikerMovementEquationDerivation_page1.png
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  • Typeset equations (12) to (17): total kinetic energy T_total with expansion, total potential energy V_total = (1/2)K_B x^2 + (1/2)K_tS(pi/2 - theta)^2, the Lagrangian L = T_total - V_total, and Lagrange's equation d/dt(dL/dq_dot) - dL/dq = dW_nc.
    2DStrikerMovementEquationDerivation_page2.png
    12.9 KB · Views: 793
  • Typeset derivation of Lagrange equations (18) to (25): partial derivatives of eq (16) with respect to x-dot, theta-dot, x and theta, their time derivatives, and substituted equations (24) and (25) for the generalized forces Qx and Q-theta.
    2DStrikerMovementEquationDerivation_page3.png
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Pages 4 through 5
 
Attachments
  • Typed page of equations for virtual work of non-conservative forces, numbered 26 to 34, with the non-conservative force vector Fc, the position vector Rc and the generalized forces Qx and Qθ, followed by two equations of motion.
    2DStrikerMovementEquationDerivation_page4.png
    32.6 KB · Views: 691
  • Typeset equations (35) to (41) showing the derivation of equations of motion for a sliding T-shaped pendulum: grouping terms, factoring out the acceleration vector into a 2x2 matrix form, and solving with the inverse matrix.
    2DStrikerMovementEquationDerivation_page5.png
    25.9 KB · Views: 674