Finding the Equation System of a Complex Mechanism: Using Lagrange Formalism

[Nagui]

Summary:: equation system of complex mechanism need to be done. Lagrange Formalism could be helpfull to do it but small errors could all destroy ..

Hi everyone,
I tried to find the equation system of the joined Mechanism (4 DoF). I think there is a mistake but I am not sure where is it . I have used the Lagrange Formalism to determine the equations. Can anybody please help me with the verification, if it is correct . Thank you very much for your help :)

 

[Dr.D]

If you intent to use Lagrange, you should begin by writing kinetic energy T and potential energy V. I don't see those in your work.