Kinematic synthesis of adjustable four-bar mechanisms for multi-phase motion generation

A four-bar linkage can satisfy up to five prescribed positions for the motion generation problem. The adjustable four-bar linkage, on the other hand, can satisfy more than five given positions by making some of the parameters adjustable. Limited work had been done in the area of motion generation problems of kinematic synthesis of adjustable four-bar linkages until Wilhelm introduced the concept of multiple adjustments. This study considers for the first time, the adjustment of a moving pivot, and the problems of three phases of motion. Various combinations of the number of prescribed positions for the motion generation problems are solved here until the prescribed positions reach the maximum permissible number. These solutions are developed for two and three phase adjustable moving pivot problems, two phase adjustable moving pivot and crank length problems, three phase adjustable crank length problems, and three phase adjustable fixed pivot problems. Equations are also developed for the most complicated cases, which are two phase adjustable moving pivot problems with three positions in each of the two phases, and three phase adjustable crank length problem with two positions in each of the three phases. Six synthesis example problems are presented which represent various topics covered in this study. Several Turbo Pascal programs are developed for solving the synthesis problems. Many user-defined AutoLISP functions and commands are specially designed for this work