Proposed solution for torque calculation. Please Check.

Hi!
I have a proposed solution but I'm not sure if it's right. I first did an analysis with the shank/lower leg given the angular velocity and acceleration of the shank at a certain time. I can draw free body diagrams from where I can generate the free body equations according to Newton's 2nd Law (please refer to the figures I've provided). From there, I can compute for the reactions at the knee joint by summing the forces along x and along y. I can now use these reactions to get the torque about the hip joint.

You see that I isolated the shank first assuming that the knee joint is fixed. Did I made the right assumption?

Bipedal Robot Design

Robot Leg
Shank Free Body diagram
Thigh Free Body Diagram
Equation for Angular Acceleration
Solving for Ax
Solving for Ay
Solving for the torque