Abstract
An index of motion-transmission characteristics γ of the spatial four-link mechanism, which has two stationary turning pairs and two moving spherical pairs, is presented through investigation of the sensitivity of the angular displacement of the links to the deviation of the kinematic constants and the forces acting at the pairs due to the external forces on the links. Generally speaking, the average of the absolute values of the sensitivities S and the average of the forces acting at the pairs F decrease rapidly in the interval [0, 0.3] and slowly in [0.3, 1] as γ increases. The γ-S and γ-F relations are approximated by the regions bounded by two rectangular hyperbolas. Consequently, it is possible to estimate the values of S and F of any mechanism at the given crank angle by means of γ.
