How do you create a moving coordinate frame that is the midpoint/average of two existing coorindate frames in simscape/ simulink?

I have a biped model with two coordinate frames. Each frame is attached to the base of each leg. I would like to create a moving coorinate frame that exists inbetween the two legs.

Answer 1

[Steve Miller]

If the frame you are trying to create exists in the physical system, you would need to add joints and parts. I suspect, however, that you want to create the frame for either displaying something in the animation, as a reference frame for measurement, or both.

1. For measurement: I recommend you do not create the frame directly, but rather do the calculations you need in Simulink or MATLAB. You can obviously calculate the location and position of the frame if you know the positions of the other two frames.
2. For animation: As above, calculate the position and orientation of the desired frame. Then, motion actuate a 6-DOF joint to place a frame (and solid geometry, such as a sphere) at that location. Important - make sure this mechanism is in a Simscape Multibody network completely independent of the robot, otherwise you will have to break algebraic loops. The two mechanisms, even though not connected by Simscape Multibody connections, will both be animated in the same Mechanics Explorer window.

--Steve