link_solver will solve for any two unknowns in a mechanical linkage system. It is precompiled to solve for systems up to 10 mechanical linkages. If the symbolic library is installed then it can be expanded indefinitely.

Example: Given the four bar linkage in the shape of a square, the top bar length and angle is 'unknown'.
[link2, angle2]=fourbar(5,90,[],[],5,270,5,180)
[link2, angle2]=link_solver(5,90,[],[],5,270,5,180)

Will correctly identify that the second link is of length 5 with angle 0.

All functions accept matrix input to solve for multiple orientations at once.
link=link_solver(1,1:360,5,[],.25,-90,[],180);
Will solve for the angles of links 2 and 3 of a mechanical slider four bar system. As linkage 1 is rotated a full 360 degrees.

draw_bar will take the output from link_solver and create a plot for a given mechanical system. This can be put in a for loop to create a movie of the motion of a mechanical linkage system.

Includes documentation, examples (with published code) and movies of mechanical systems.

(fourbar is just a wrapper for link_solver to solve for four bar linkages.)

Also be found on GitHub:
http://github.com/jedediahfrey/Jedediah-Frey-s-MATLABCentral-Projects/tree/master/linkage_solver/