Fundamental Concepts in Kinematics
This chapter explains kinematic and design distinctions among select planar and spatial mechanisms, mechanism components and mechanism construction, Mechanism mobility, Gruebler's equation and number synthesis. It discusses Grashof criteria and the circuit defect, the transmission angle and its relationship with follower-link forces, mechanism inversion, and the passive degree of freedom and paradoxes to Gruebler's equation. The fundamental objective in mechanical system design is to produce specific controlled output motions for supplied input motions. The slider-crank mechanism can be theoretically described as a planar four-bar mechanism having a follower link of infinite length. Number synthesis involves the determination of alternate mechanism solutions for a given mobility. Grashof's criteria are used to determine the link rotation behavior or link rotatability of four-bar mechanisms. Attaching a grounded link pair or a dyad to the coupler of the planar four-bar mechanism produces a planar multiloop six-bar mechanism.