Three-D parallel translation mechanism for virtual axle NC machinetool, robot and mechanical measurer

Abstract

A 3D parallel translation mechanism for the virtual-axle machine-tool and robot is composed of moving platform, static platform and three branches. Each branch consists of two rotation sets and one cylindrical set, which are serially linked in parallel mode. Said branch is linked between moving and static platforms. Two branches are parallel but perpendicular to the third one. The 3D translation output of moving platform can be controlled by driving three rotation sets on static platform. Its advantages are simple structure, decouple nature between input and output, big work space and easy manufacture and installation.

Description

technical field [0001] The invention relates to a virtual-axis numerical control machine tool, a robot and an executive mechanism of a virtual-axis mechanical measuring machine, specifically providing a new type of parallel mechanism for a virtual-axis numerical control machine tool with a parallel structure, a parallel robot and a virtual-axis mechanical measuring machine. Background technique [0002] Parallel structure CNC machine tool refers to the machine tool with parallel mechanism as the executive mechanism. This machine tool is considered to be a revolution in the structure of machine tools since the 20th century. At present, prototypes of this machine tool have been developed in the United States, Japan and other countries, and the parallel mechanisms adopted are all traditional Stewart mechanisms. This mechanism for controlling the position and direction of the tool in space is mainly composed of a base, a moving platform and a connecting rod. The base and the mov...

AI Technical Summary

Problems solved by technology

[0003] The Stewart mechanism has the following disadvantages: ①The positive solution of kinematics is very difficult; ②The position and direction of the motion platform are strongly coupled; ⑧The working space is small; ④It is difficult to manufacture high-precision ball pairs

[0005] ①The kinematics positive solution is an 8-degree closed solution, and a one-dimensional 8-degree equation needs to be established and solved, which makes the control and trajectory planning of the system more complicated

[0006] ②The motion input and output of the three-dimensional translation mechanism are strongly coupled, which makes the system control very complicated

[0007] ③ There are virtual constraints in the mechanism, making its manufacture and assembly more complicated

[0008] ④The working space is still relatively small

For 6-SPS and 6-RSS mechanisms, the movable platform has 6 spatial degrees of freedom relative to the base platform, so the space pose of the end effector is relatively flexible, but the mechanism is complex, and the kinematics positive solution and error analysis and correction are difficult ; For the 3-RPS mechanism, the degree of freedom is 3, the flexibility of its space pose is slightly poor, but the structure is simple, because the undesired output of the 3-RPS mechanism is not constant and there is no decoupling, so its error analysis and correction are still more complex

In addition, the above three parallel mechanisms all contain multiple spherical pairs, which are complicated to manufacture and assemble, which is not conducive to improving the measurement accuracy.

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