Two Position Coordinated Motion Synthesis with a RRRR Mechanism
Schematic Diagram of a 4 Bar RRRR Linkage
In this experiment you will asked to design a RRRR mechanism whose input and output motion is coordinated at at least two given positions. That is, suppose the input link (link 2) is oriented at 30 degrees, the output link is required to have an orientation of 75 degrees. Likewise, suppose the input link (link 2) is oriented at 45 degrees, the output link is required to have an orientation of 120 degrees. Since we are concerned only about two pairs of poisitions, therefore it becomes a problem of coordinated two position synthesis. Such synthesis is also referred to as function snythesis. Why this is so is easily understandble, if you reframe the earlier problem in a different fashion, where we may seek the input angle (theta_2) to be 30 degrees and 60 degrees, while the output angle (theta_4)s are 100*sin(30 degrees) and 100*sin(60 degrees) respectively, thereby making theta_4 = 100*sin(theta_2) at two given orientations of the input link.
While such problems can be solved analytically, a graphical method of synthesis will be used here. Go to the Procedure Tab to see an animated guide to the geometrical constructions required. An animation of a sample 4 bar RRRR mechanism passing through 2 given sets of orientations can bee seen by clicking on the Demo Tab.