Link-systems have been around for a long time and are still used to control motion in diverse applications such as
automobiles, robots and industrial machinery. This study presents a procedure involving the use of a genetic algorithm
for the optimal design of single four-bar link systems and a double four-bar link system used in diesel engine. We
adopted the Successive Zooming Genetic Algorithm (SZGA), which has one of the most rapid convergence rates among
global search algorithms. The results are verified by experiment and the Recurdyn dynamic motion analysis package.
During the optimal design of single four-bar link systems, we found in the case of identical input/output (IO) angles that
the initial and final configurations show certain symmetry. For the double link system, we introduced weighting factors
for the multi-objective functions, which minimize the difference between output angles, providing balanced engine
performance, as well as the difference between final output angle and the desired magnitudes of final output angle. We
adopted a graphical method to select a proper ratio between the weighting factors.