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Andrew85

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Hi, revising for my christmas exams and am really struggling to get my bearing with Lagrangian Equations. I think its just the initial steps that I can't seem to follow.

This is a tutorial question that I just can't get my head around:

Use Lagrange’s Equations to obtain the equations of motion of the vehicle model shown, about the equilibrium position. The vehicle is symmetrical about the vertical centre line and you may assume small displacements and hence neglect any lateral movements of the masses, spring ends and link pivots.

Note: L1 = (L2 + L3)/2 i.e. the spring is attached half way along the link and the links attaching the wheels to the body are horizontal ( φ1 = φ2 = 0 ) at the equilibriumposition shown. Also, because we are interested in motion about the equilibriumposition it is not necessary to take into account any change in gravitational potential energy associated with the motion of the masses.

There should be a pic of the problem attached. Thanks for any help on how to get started.

This is a tutorial question that I just can't get my head around:

Use Lagrange’s Equations to obtain the equations of motion of the vehicle model shown, about the equilibrium position. The vehicle is symmetrical about the vertical centre line and you may assume small displacements and hence neglect any lateral movements of the masses, spring ends and link pivots.

Note: L1 = (L2 + L3)/2 i.e. the spring is attached half way along the link and the links attaching the wheels to the body are horizontal ( φ1 = φ2 = 0 ) at the equilibriumposition shown. Also, because we are interested in motion about the equilibriumposition it is not necessary to take into account any change in gravitational potential energy associated with the motion of the masses.

There should be a pic of the problem attached. Thanks for any help on how to get started.