ON THE KINEMATIC AND DYNAMIC CHARACTERISTICS AND ERROR ANALYSIS OF A CLASS OF SPATIAL MECHANISMS.

摘要

The objective of this investigation is to apply recent advances in the kinematics and analytical mechanics to develop systematic design methods capable of predicting the performance characteristics and effects of manufacturing tolerances of a class of spatial mechanisms with realistic complexity.; This research concentrates in three areas of development: (1) the effect of overclosure on the kinematics and dynamics of mechanisms; (2) design methods on the investigation of the dynamics of spatial mechanisms; and (3) three-dimensional models for the error analysis of mechanisms with manufacturing tolerances. Analytical techniques are developed and applied to the design of two groups of mechanisms. The first group is a class of high-speed shaft couplings including the UNI-LAT coupling which after mounting is an overconstrained mechanism, the commonly used Hooke joint, and the tripode joint that has been widely used as the shaft coupling for the front-wheel-drive vehicle. The second group includes two industrial robots, the PUMA 500 and SEIKO 3000.; On the investigation of the UNI-LAT coupling, a method for complete force analysis of overconstrained, statically indeterminate mechanisms is presented. It involves development of an analytical technique coupled with an experimental method to completely specify the dynamic state of an overconstrained mechanism.; The investigation of the tripode joint provides dynamic analysis of a class of mechanisms in which there are no linkage-equivalents and therefore are difficult to analyze.; In the mechanical error analysis three-dimensional models are developed. They are used to describe the tolerances of links as well as the clearances at the joints of a mechanism, and they provide the necessary transformation of the notations of machine design to kinematic parameters. The theory is illustrated in the case of the universal Hooke joint and the error analysis of two robot manipulators.