A four-degree-of-freedom parallel mechanism with additional branch chain base rotation

Abstract

The invention discloses a four-degree-of-freedom parallel mechanism added with branched chain seats for rotation. The four-degree-of-freedom parallel mechanism comprises a rack, a rotation mechanism, a first branched chain seat, a second branched chain seat, a third branched chain seat, a first branched chain group, a second branched chain group, a third branched chain group and a movable platform, wherein the rack comprises a base, a first vertical column and a second vertical column; the first vertical column and the second vertical column are fixed to the two ends of the base; the rotation mechanism is installed in the rack, and the first branched chain seat and the third branched chain seat are connected with the rotation mechanism respectively; the second branched chain seat is fixed to the upper end of the base; one end of each of the first branched chain group, the second branched chain group and the third branched chain group is connected with the first branched chain seat, the second branched chain seat and the third branched chain seat respectively, and the other end is connected with the movable platform; and connection between the two ends of each of the first branched chain group, the second branched chain group and the third branched chain group is realized through a spherical hinge, thus a spatial parallel closed-loop structure is formed. The mechanism is large in working space and capable of avoiding singular configurations, improves the movement performance and rigidity, solves the problems of positive solution and certain solution of the mechanism, and simplifies a control system.

Description

technical field [0001] The invention belongs to the field of numerical control manufacturing equipment, in particular to a four-degree-of-freedom parallel mechanism with additional branch chain seat rotation. Background technique [0002] In the field of grand manufacturing, the welding displacement of large components, the assembly and docking of large parts or large components all require devices that can move in a large range, rotate around any direction, have reasonable precision, and have a strong bearing capacity to work together. At present, in the assembly of large parts, the conventional method is to assist the operation with equipment such as bridge cranes and forklifts. Due to the large position positioning error of such equipment and the lack of angle positioning capabilities, the operation efficiency is low and the operation safety hazards are many; In terms of large-scale welding , In addition to cranes and forklifts, there have been reports on the application ...

AI Technical Summary

Problems solved by technology

[0003] Chinese patent CN105818137A discloses a parallel mechanism with three-dimensional translation, which uses three servo motors installed on a fixed platform, and the connecting hinge also serves as a coupling to drive three sets of retractable branch chains synchronously. Although it solves the fixed solution problem of the positive solution of the mechanism, However, this mechanism has a small working space and is not suitable for large-scale work; Chinese patent CN103240729A discloses a space three-translational parallel manipulator, including a fixed frame, a moving platform, and three supports symmetrically arranged between the fixed frame and the moving platform. Chain group, each group of branch chains is divided into near-frame rods and far-frame rods to form a space-axisymmetric multi-link structure. The limitation lies in poor rigidity and small working space

Unable to meet the requirements for processing large workpieces

Chinese patent CN103846649A discloses a two-stage parallel robot device for precision assembly. The device is composed of a rope parallel mechanism and a Stewart parallel mechanism in series. The moving platform of the rope parallel mechanism needs to be pulled upwards by occupying the driving in the workshop. Positioning, driving the rope branch chain can only adjust the posture of the cable platform. The limitation is that when assembling a large workpiece, the fixed trolley occupies too much area, and the one-way force characteristic of the rope makes the positioning accuracy of the cable platform poor. The movement of the moving platform limits the installation of equipment and the operation of personnel in the work area at the same time, and it is unsafe

Chinese patent CN104117809A discloses a car body welding positioner, which includes a driving part and a driven part. Its limitation is that the device has less degrees of freedom and is used for welding specific workpieces, but it cannot be used as an assembly robot, and its versatility is low. Difference

However, there are two problems with this mechanism: one is that the frame must be very tall to obtain a larger working space, and the horizontal working range of the mechanism is relatively small; Limited paths available

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