1. The problem statement, all variables and given/known data I have to derive newton euler equations of an inverted telescopic pendulum with two links. I will use this model to simulate biped walking. The leg link is assumed to be massless and it carries the body link. The model at final stage should be 3d. In 3d case the hip namely the joint between two links will have all 3 rotations. The leg is assumed to be sticked to the ground. 2. Relevant equations newton-euler equations 3. The attempt at a solution I do not know the procedure to derive the equations. However, I think the 2d case is not that hard, but I do not know what to do in 3d case. I am not asking for a full answer. I only need someone to guide me to the right track. Thanks..