Handling mechanisms of parallel structure and their application in modern equipment

Abstract

The mechanisms of parallel structure differ in the feature that the output unit (actuator) is connected to the base with several kinematic chains. In this case, mobile girder construction [1, 2] takes place, which is distinguished by the improved parameters of the load� ing ability and accuracy in comparison with the con� sole construction of manipulators having a series arrangement of units. In addition, it is possible to note the simplicity of fabrication of mechanisms of parallel structure because all kinematic chains, as a rule, have identical architecture. In addition to these advantages of such mechanisms, there is also the possibility to mount the engines on the base or very close to it. It decreases the dynamic loads and increases the velocity of motion. The indicated features make it possible to speak about the unique possibilities of mechanisms of paral� lel structure. Therefore, despite certain disadvantages related to decreasing the working volume and the pres� ence of singularities, these mechanisms can find a broad application as simulators, technological and medical robots, measuring and test mechanisms, and manipulators used in aggressive media. At Blagonravov Institute of Engineering Science (IES), Russian Academy of Sciences, a number of serious results were obtained in this field. In particular, the most complete classification of these objects was carried out, methods of their analysis and synthesis [3] were developed, and the dynamic properties of mech� anisms of a similar type were investigated [4, 5]. We presented certain solutions in the field of handling mechanisms of the parallel structure enabling us to solve efficiently the important technical problems. One serious problem is manipulation with the models of aerospace systems in a wind tunnel. The problem is complicated by the fact that the model can be affected by the air flow with a force of about 1.5 t; in this case, it is necessary to have six degrees of freedom of the mechanism and to shade the air flow minimally. For solving the formulated problem, a number of schemes [6, 7], the distinctive feature of which is the arrangements of all drives outside the working zone (Fig. 1), have been synthesized. Similar solutions can be used in other technical applications, in particular, during manipulation in aggressive media (space, ocean).