hw2 #3 Posted by Kelsey Wilson on Tue 21 of Oct, 2014 22:27 EDT Does anyone know how to relate points D and C to the loop closure equation in question #3? I have the loop closure equation as L1i+L4i4=L2i2+L3i3

hw2 #3 Posted by Kelsey Wilson on Tue 21 of Oct, 2014 22:27 EDT Does anyone know how to relate points D and C to the loop closure equation in question #3? I have the loop closure equation as L1i+L4i4=L2i2+L3i3

Posted by D. Dane Quinn on Tue 21 of Oct, 2014 22:49 EDT As we discussed in class today, points D and C are not part of the loop closure equation. However, once you solve the loop closure equation for the angles (and likewise the velocity equations for the angular speeds) you can use these to go back and determine the position and velocity of any point in the mechanism.

Posted by Kelsey Wilson on Tue 21 of Oct, 2014 23:48 EDT I guess I’m confused on how to solve for the velocity. I found the angles and angular speeds through position and velocity analysis, but am not sure how to relate that to the velocity of D and C. I am trying to go off of problem 6 from hw#1 where the velocity of B was found in the i and j directions, but I’m not sure where that came from. is it always distance times angular speed in the j directions?

Posted by D. Dane Quinn on Wed 22 of Oct, 2014 05:38 EDT Once you have the angles and angular speeds from the position and velocity analysis, then go back and find, for example, the position of D with respect to a point fixed in the ground. Knowing all of the angles you can find this vector. Likewise, the velocity of D is found by evaluating the change in position (taking a derivative) and then using th known angles and angular speeds.