KNES 300 Lecture Notes - Lecture 17: Free Body Diagram, Ankle, Inverse Dynamics
5 Apr 2017
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Inverse dynamics: goal: resultant joint kinetics, internal forces and moments between joints, from input data, body segment kinematics (get information from motion capture, external forces (gravity, grf, using, musculoskeletal model. How to do inverse dynamics: lots of approaches, we will use the iterative newton-euler method. I. e. , if you are only interested in the right leg, do not include the left leg in the drawing. Frx: sum of forces in the y-direction, use +9. 81 for g the equation already takes into account the negative sign that should be with gravity. Example: the shank/knee: notice, ankle resultants on the shank are equal and opposite to ankle resultants on the foot, knee resultants (fryp, frxp, trp) are unknown, subscripts: r = resultant, d = distal, p = proximal. Thought exercise: how would you now calculate the resultant hip forces and moments, figure out what is happening at the knee, flip the numbers, and then find the calculations for the hip.
