Two-rotation two-motion four-freedom-degree parallel excitation platform

Abstract

A two-rotation two-motion four-freedom-degree parallel excitation platform comprises a movable platform, a fixed platform, four driving branches of the same structure and a middle restraint branch, wherein the four driving branches and the middle restraint branch are used for connecting the two platforms. The four driving branches are respectively of a PSS structure. In each driving branch, a linear module (in an electric driven mode) is fixed to the fixed platform and connected with a sliding block through a sliding pair, one end of a connecting rod is connected with the sliding block through a first ball pair, and the other end of the connecting rod is connected with the movable platform through a second ball pair. The middle restraint branch is of a PPU structure. A guide rail in the middle restraint branch is fixed to the fixed platform, one end of a lower connecting rod is connected with the guide rail through a first sliding pair, the other end of the lower connecting rod is connected with one end of an upper connecting rod through a second sliding pair, and the other end of the upper connecting rod is connected with the movable platform through a universal hinge. The two-rotation two-motion four-freedom-degree parallel excitation platform can achieve the space two-dimensional independent rotational freedom degree and the two-dimensional independent movement freedom degree and has the advantages of being simple and compact in structure, rapid in dynamic response, easy to install and maintain and the like.

Description

technical field [0001] The invention relates to a parallel mechanism, in particular to a parallel excitation platform. Background technique [0002] Before industrial products leave the factory, they generally have to pass the inspection of dynamic environment. In order to save costs and improve efficiency, the working environment of the product is often simulated in the laboratory, and a stable and experienced vibration test is usually carried out. The vibration test in the laboratory is generally completed by a shaking table. So far, there are many vibration platforms on the market, which can be roughly divided into one-dimensional vibration platforms and multi-dimensional vibration platforms. The one-dimensional vibration platform is mainly used in the testing of precision small parts. It is suitable for vertical and horizontal vibration in the laboratory due to its low frequency, large load and low price. However, in nature and engineering, a large number of vibration ...

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Problems solved by technology

However, the research on parallel mechanisms with few degrees of freedom is extremely unbalanced. Among them, parallel mechanisms with two and three degrees of freedom are more mature, while the research on parallel mechanisms with four or five degrees of freedom is more complicated and still in its infancy, which limits this type of parallel mechanism to a certain extent. The development and application of institutions, but its demand is very large, so the research on institutions in this area has broad application prospects

[0003] Chinese patent CN1387977A proposes a four-degree-of-freedom parallel mechanism that can realize two rotations and two shifts. It is also driven by several groups of moving pairs. It has the characteristics of high transmission efficiency, good rigidity, and good force performance. The disadvantage is that , there are too many drive branches, the structure is more complicated, and the installation and maintenance are inconvenient

Chinese patent CN102240911 proposes a non-completely symmetrical four-degree-of-freedom parallel mechanism. Its structure is relatively compact, and its branches are simple and easy to manufacture and install.

Chinese patent CN201573026U proposes a symmetrically arranged four-degree-of-freedom parallel mechanism, which has a compact structure and high rigidity, but its disadvantage is that its driver is placed on the branch, which increases the mass of the branch and improves the dynamic response characteristics of the mechanism. not good

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