In this study, a systematic method of the kinematic synthesis of RSSR spatial four-bar mechanism is developed. This procedure of kinematic synthesis includes both the type synthesis and dimensional synthesis.
For the stage of type synthesis, firstly practical spatial four-bar mechanisms suitable for the three customary tasks of kinematic synthesis are determined based on the heuristic knowledge and the characteristics of motion. Then a systematic modeling method is suggested to resolve the redundancy and passivity problems arising in these spatial mechanisms.
For the stage of dimensional synthesis, firstly two sets of mobility conditions for a RSSR mechanism are developed to ensure the crank-motion. First set of the mobility conditions is the Grashof-type necessary conditions expressed only in terms of link lengths. The other set of the mobility conditions provides the necessary and sufficient conditions in algebraic form accounting for the constraint of the deviation angle. For some special cases, these equations are simplified for easy application to practical problems. Then a dimensional synthesis procedure using Euler parameters along with quaternion algebra is proposed for the generality of the algorithm.
This algorithm is applied to the synthesis of an industrial sewing machine and solar panel deploy mechanism. As expected, the algorithm provides a trouble-free solution in contrast to the conventional algorithms along with good numerical efficiency. However, these merits are disappeared when the numbers of design positions increase.
