Quasi-zero-stiffness based six-degree-of-freedom absolute displacement and attitude measurement device

Patent metadata

Field	Value
Publication number	US-12013237-B2
Application number	US-202017121648-A
Country	US
Kind code	B2
Filing date	Dec 14, 2020
Priority date	Jul 6, 2020
Publication date	Jun 18, 2024
Grant date	Jun 18, 2024

Abstract

The present invention discloses a quasi-zero-stiffness (QZS) based six-degree-of-freedom (6-DOF) absolute displacement and attitude measurement device. A lower end coil and an upper end coil are respectively charged with currents in the opposite directions; The electromagnetic field and the magnetic fields of an upper magnet and a lower magnet per se are mutually acted to produce an electromagnetic stiffness opposite to the stiffness of a spring. The stiffness of the whole leg is close to zero stiffness. When the to-be-measured platform generates space motion, the reference platform is in the stationary state. At this point, the deformation amounts of the six legs can be measured by laser displacement sensors. The six deformation amounts are respectively inputted into the displacement and attitude resolver, and by forward kinematic solution of the 6-DOF device, the displacement and the attitude of the to-be-measured platform can be obtained.

First claim

What is claimed is:

1. A QZS based 6-DOF absolute displacement and attitude measurement device, comprising a reference platform, a to-be-measured platform, a displacement and attitude resolver, and six QZS legs with the same structures, wherein two ends of each QZS leg are respectively connected with the reference platform and the to-be-measured platform through spherical joints;
each QZS leg includes a lower support, a spring, a shaft, a lower end coil, an upper end coil, a lower end magnet, an upper end magnet, an upper support, and a laser displacement sensor; the upper end magnet and the lower end magnet are in a mutual repulsion state and are respectively fixed to the shaft through two retaining rings; the lower end coil and the upper end coil are located on outer sides of the lower end magnet and the upper end magnet and are fixed to an inner wall of the lower support; there is no relative motion among the lower end coil, the upper end coil, and the lower support; a space is reserved between the lower end coil and the upper end coil; the lower end coil and the upper end coil are charged with currents in opposite directions; one end of the shaft is connected with an end part of the inner wall of the lower support through the spring, and another end of the shaft is connected with the end part of the upper support; the laser displacement sensor is used for measuring deformation amount information of each of the six QZS legs; each laser displacement sensor inputs the deformation amount information into the displacement and attitude resolver; and the displacement and attitude resolver solves to obtain displacement and attitude of the to-be-measured platform.

2. The QZS based 6-DOF absolute displacement and attitude measurement device according to claim 1 , wherein the upper end magnet and the lower end magnet have the same appearances and structures, and a magnetizing direction of each of the upper end magnet and the lower end magnet is along a longitudinal axis of each QZS leg; the upper end magnet and the lower end magnet are in the mutual repulsion state.

3. The QZS based 6-DOF absolute displacement and attitude measurement device according to claim 1 , wherein the two retaining rings are respectively a lower end retaining ring and an upper end retaining ring; the upper end magnet and the lower end magnet are respectively fixed to the shaft through the upper end retaining ring and the lower end retaining ring; the two retaining rings are in dead lock.

4. The QZS based 6-DOF absolute displacement and attitude measurement device according to claim 1 , wherein the upper end coil and the lower end coil have the same appearances and structures; a thickness of each of the upper end coil and the lower end coil along a longitudinal axis of each QZS leg is the same as a thickness of each respective one of the upper end magnet and the lower end magnet along the longitudinal axis of each QZS leg.

5. The QZS based 6-DOF absolute displacement and attitude measurement device according to claim 4 , wherein a width of the space between the upper end coil and the lower end coil is equal to a thickness of each respective one of the upper end coil and the lower end coil along the longitudinal axis of each QZS leg.

6. The QZS based 6-DOF absolute displacement and attitude measurement device according to claim 1 , wherein inner diameters of the upper end coil and the lower end coil are larger than outer diameters of the lower end magnet and the upper end magnet.

7. The QZS based 6-DOF absolute displacement and attitude measurement device according to claim 1 , wherein one end of the upper support is nested in the inner wall of the lower support and is connected with the shaft, and the other end of the upper support is connected with the reference platform through a spherical joint.

8. The QZS based 6-DOF absolute displacement and attitude measurement device according to claim 7 , wherein the laser displacement sensor is mounted on an outer wall of a non-nested end of the upper support, and a space is reserved between the laser displacement sensor and an end part of the lower support close to the laser displacement sensor.

Assignees

• Univ Chongqing
• Univ Shanghai

Inventors

• Pu Huayan
• Zhao Jinglei
• Luo Jun
• Zhao Jiyun
• Kong Qinghua
• Ding Jiheng
• Wang Min
• Sun Yi
• Li Zong
• Bai Long
• Peng Yan
• Xie Shaorong

Classifications

• G01B7/14

  for measuring distance or clearance between spaced objects or spaced apertures (G01B7/30 takes precedence) · CPC title

• G01B7/102

  Height gauges · CPC title

• F16F6/005

  using permanent magnets only · CPC title

• F16F3/026

  to give a zero-spring rate characteristic · CPC title

• F16F2228/06

  Stiffness · CPC title