三自由度并联工装

By employing a first double-headed Hooke hinge and a second double-headed Hooke hinge to form a parallel constraint mechanism in a three-degree-of-freedom parallel fixture, the Jacobian matrix singularity problem caused by coplanar or parallel branches is solved, thereby achieving stability of platform motion and cost reduction.

CN224509684UActive Publication Date: 2026-07-17HANGZHOU GUOCHEN ZHENGYU TECH CO LTD
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Utility models(China)
Current Assignee / Owner
HANGZHOU GUOCHEN ZHENGYU TECH CO LTD
Filing Date
2025-07-24
Publication Date
2026-07-17

AI Technical Summary

Technical Problem

When the branches of a traditional three-degree-of-freedom parallel fixture are coplanar or parallel, the Jacobian matrix singularity causes the platform to lose control of its motion. Furthermore, the use of Hooke hinges in existing technologies, which only replace the ends of the branches, fails to solve the problem of coupling between the degrees of freedom of the branches.

Method used

A first double-headed Hooke hinge and a second double-headed Hooke hinge are used to form a parallel constraint mechanism through a first rotating shaft and a second rotating shaft, which replaces the traditional ball joint and restricts the degree of freedom of the branch to rotate around the axis. Combined with a sealing cover, the through hole is closed to protect the sensor.

Benefits of technology

This completely avoids the Jacobian matrix singularity problem, ensures platform motion stability, reduces production costs, and improves cutting force measurement accuracy.

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Abstract

本实用新型公开了三自由度并联工装，包括固定座、驱动件、连接铰组及平台支座；驱动件安装于固定座，平台支座顶面转动安装有刀具座；连接铰组包括：第一虎克铰、第一连杆、第二虎克铰依次串联构成的第一双头虎克铰链；第三虎克铰、第二连杆、第四虎克铰依次串联构成的第二双头虎克铰链；平台支座底面设有第一转轴，驱动件顶端设有第二转轴，第一虎克铰和第三虎克铰分别铰接于第一转轴两端，第二虎克铰和第四虎克铰分别铰接于第二转轴两端。第一双头虎克铰链与第二双头虎克铰链通过第一转轴和第二转轴形成平行约束机构，替代传统球铰，刚性限制支链绕轴线旋转自由度，彻底避免支链共面或平行时导致的雅可比矩阵奇异问题，保障平台运动稳定性。
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Claims

1. A three degree of freedom parallel fixture, characterized by, include: Fixed base, drive unit, connecting hinge assembly and platform support; The drive component is mounted on a fixed base, and a tool holder is rotatably mounted on the top surface of the platform support; The connecting hinge assembly includes: The first double-headed Hooke hinge is formed by connecting the first Hooke hinge, the first connecting rod, and the second Hooke hinge in sequence. The second double-headed Hooke hinge is formed by the third Hooke hinge, the second connecting rod, and the fourth Hooke hinge connected in series. The platform support has a first rotating shaft on its bottom surface and a second rotating shaft on its top end. The first and third Hooke hinges are respectively hinged to the two ends of the first rotating shaft, and the second and fourth Hooke hinges are respectively hinged to the two ends of the second rotating shaft.

2. The three-degree-of-freedom parallel fixture of claim 1, wherein The fixed base includes a base, a support plate, and a support seat. One end of the support plate is connected to the base, and the other end of the support plate is connected to the support seat. The driving component is installed on the base, and the output end of the driving component passes through the support seat and is connected to a connecting block. The second rotating shaft is fixedly set on the connecting block.

3. The three degree of freedom parallel fixture of claim 2, wherein, The connecting block is provided with guide posts on both sides symmetrically, and the support base is provided with a first through hole that slides with the guide posts.

4. The three-degree-of-freedom parallel fixture of claim 3, wherein, The guide post is provided with a first limiting block and a second limiting block at both axial ends. The outer diameter of the first limiting block and the outer diameter of the second limiting block are larger than the diameter of the through hole.

5. The three degree of freedom parallel fixture of claim 1 wherein, The tool holder includes a base, a spindle, and a bearing. The base is fixedly installed on the top surface of the platform support. The inner ring of the bearing abuts against the outer wall of the spindle, and the outer ring of the bearing abuts against the inner wall of the base.

6. The three degree of freedom parallel fixture of claim 5 wherein, The bearing has a retaining ring at one end of its inner ring, which abuts against the shoulder of the spindle for positioning. The other end of the bearing's inner ring abuts against a locking nut, which engages with the threads on the outer wall of the spindle.

7. The three degree of freedom parallel fixture of claim 5 wherein, It also includes a sealing cover. The platform support has a second through hole for mounting the base body. The diameter of the second through hole is larger than the diameter of the base body. One end of the sealing cover is fixedly covered on the outer peripheral wall of the base body, and the other end of the sealing cover is fixedly connected to the platform support.

8. The three degree of freedom parallel fixture of claim 7 wherein, The outer circumferential wall of the sealing cover is provided with a clamp.