Parallel mechanism with six degrees of freedom used for virtual shaft numerical control machine tool and parallel robot

Abstract

The invention is a six-freedom parallel used in virtual shaft digital controlled machine tool, measurer and parallel robot, composed of dynamic platform, static platform and a mixed chain leg and four same simply open chain legs. The mixed chain leg is composed of a planar closed-loop structure and an open-chain structure, the planar closed-loop structure is composed of five rods by five rotary auxiliaries in turn, two components of the planar closed-loop structure are mechanically connected with the static platform through rotary auxiliaries; the open-chain structure is composed of three components by two parallel-axis rotary auxiliaries, respectively, one end and two planar-rotating components in the planar closed-loop structure compose a compound hinge, and the other end is connected with the dynamic platform through a rotary auxiliary, mechanically; the simple open-chain structure is composed of two components connected by a ball auxiliary, one component is connected with the static platform and the other component is connected with the dynamic platform. Control of the motion of six driving joints on the static platform can control the platform to implement 3D translation and 3D rotary output.

Description

technical field [0001] The present invention relates to a class of executive mechanisms of machine tools, robots and coordinate measuring machines, and specifically provides a class (4 types) of new six-degree-of-freedom machines for virtual-axis CNC machine tools with parallel structures, virtual-axis parallel coordinate measuring machines and parallel robots parallel mechanism. 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, China and other countries, and most of the parallel mechanisms used are traditional Stewart mechanisms or their improved mechanisms. This mechanism for controlling the position and attitude of the tool in space is mainly composed of a base, a moving platform...

AI Technical Summary

Problems solved by technology

The Stewart mechanism and its improved mechanism have the following disadvantages: ① It is difficult to solve the kinematics forward solution; ② The position and direction of the motion platform are strongly coupled; ③ The movement space is small; ④ It is difficult to manufacture high-precision ball pairs

[0004] 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

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

[0005] ③ There are virtual constraints in the mechanism, making its manufacture and assembly more complicated

[0006] ④The working space is still relatively small

At present, the existing relatively mature parallel coordinate measuring machine structures include 6-SPS 6-RSS and 3-RPS. For 6-SPS and 6-RSS mechanisms, since their movable platform has 6 The degree of freedom in space, so the space pose of the end effector is relatively flexible, but due to the relatively complex structure of the mechanism and fewer space constraints, it is difficult to solve the end effector

[0008] Since the above-mentioned structures contain more spherical pairs, their manufacture and assembly are more complicated.

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