Multi-dimensional magnetic negative-stiffness mechanism and multi-dimensional magnetic negative-stiffness vibration isolation system composed thereof
A multi-dimensional magnetic negative-stiffness mechanism and a multi-dimensional magnetic negative-stiffness vibration isolation system composed thereof are provided. The multi-dimensional damping system is composed of a positive-stiffness mechanism, a multi-dimensional negative-stiffness mechanism, a floating frame, a vibration isolated body, and a mounting base. The positive-stiffness mechanism is a traditional elastic element connected to the vibration isolated body and the mounting base, and provides supporting forces in an X direction, a Y direction, and a Z direction, and a basic vibration isolation function. The multi-dimensional negative-stiffness mechanism is composed of at least two negative-stiffness magnetic groups. Each negative-stiffness magnetic group may provide one-dimensional or two-dimensional negative stiffness. Through a series connection of the at least two negative-stiffness magnetic groups, a two-dimensional or three-dimensional negative-stiffness effect may be implemented to improve the vibration isolation performance of the system in multiple dimensions.
1. A multi-dimensional magnetic negative-stiffness mechanism, comprising: a mounting base, a floating frame, a two-dimensional magnetic negative-stiffness unit, and a one-dimensional magnetic negative-stiffness unit, wherein
the two-dimensional magnetic negative-stiffness unit comprises a two-dimensional negative-stiffness magnetic group, and the one-dimensional magnetic negative-stiffness unit comprises a one-dimensional negative-stiffness magnetic group;
the floating frame comprises a linear guide rail and a permanent magnet mounting frame; the permanent magnet mounting frame makes one-dimensional linear movement along the linear guide rail; a three-dimensional rectangular coordinate system OXYZ is established with a main bearing direction as a Z direction, the linear guide rail is arranged along the Z direction, two negative-stiffness directions of the two-dimensional negative-stiffness magnetic group are respectively arranged along an X direction and a Y direction, and a negative-stiffness direction of the one-dimensional negative-stiffness magnetic group is arranged along the Z direction;
the two-dimensional negative-stiffness magnetic group comprises two two-dimensional moving magnets linearly arranged along the Z direction and a two-dimensional fixed magnet located between the two-dimensional moving magnets; the two-dimensional fixed magnet and the two-dimensional moving magnets are all magnetized along the Z direction, and magnetizing directions of the two two-dimensional moving magnets are the same and are opposite to a magnetizing direction of the two-dimensional fixed magnet;
the one-dimensional negative-stiffness magnetic group comprises two one-dimensional fixed magnets linearly arranged perpendicular to the Z direction and a one-dimensional moving magnet located therebetween;
the linear guide rail and the two one-dimensional fixed magnets are all fixed onto the mounting base, and the two two-dimensional moving magnets are both fixed onto a vibration isolated body; alternatively, the linear guide rail and the two one-dimensional fixed magnets are all fixed onto the vibration isolated body, and the two two-dimensional moving magnets are both fixed onto the mounting base;
the one-dimensional moving magnet and the two-dimensional fixed magnet are both fixed onto the permanent magnet mounting frame to make one-dimensional linear movement in the Z direction along the linear guide rail along with the permanent magnet mounting frame;
an equivalent stiffness K Z of entire multi-dimensional magnetic negative-stiffness mechanism n the Z direction satisfies a following relationship:
k
z
=
k
ZZ
k
ZF
k
ZZ
+
k
ZF
where K zz is positive stiffness generated by the two-dimensional magnetic negative-stiffness unit in the Z direction, and K ZF is negative stiffness generated by the one-dimensional magnetic negative-stiffness unit in the Z direction;
When K ZF <0<−K ZF <K ZZ , K Z <0, and the entire multi-dimensional magnetic negative-stiffness mechanism is a three-dimensional magnetic negative-stiffness mechanism; and
when K ZF <0<K ZZ ≤−K ZF , K Z ≥0, and the entire multi-dimensional magnetic negative-stiffness mechanism is a two-dimensional magnetic negative-stiffness mechanism in the X direction and the Y direction.
2. The multi-dimensional magnetic negative-stiffness mechanism according to claim 1 , wherein the two-dimensional negative-stiffness magnetic group comprises two two-dimensional negative-stiffness magnetic groups, the one-dimensional negative-stiffness magnetic group comprises one one-dimensional negative-stiffness magnetic group, and the two two-dimensional negative-stiffness magnetic groups are distributed on two sides of the one-dimensional negative-stiffness magnetic group along the X direction or the Y direction.
3. The multi-dimensional magnetic negative-stiffness mechanism according to claim 1 , wherein the two-dimensional negative-stiffness magnetic group comprises one two-dimensional negative-stiffness magnetic group, the one-dimensional negative-stiffness magnetic group comprises two one-dimensional negative-stiffness magnetic groups, and the two one-dimensional negative-stiffness magnetic groups are distributed on two sides of the two-dimensional negative-stiffness magnetic group along the X direction or the Y direction.
4. The multi-dimensional magnetic negative-stiffness mechanism according to claim 1 , wherein the one-dimensional fixed magnets and the one-dimensional moving magnet are all formed by stacking a plurality of magnets, and in the magnets stacked on top of each other, magnetizing directions of adjacent magnets are opposite; and magnetizing directions of magnets on a same layer of two one-dimensional fixed magnets are the same and are opposite to magnetizing directions of magnets on a same layer of the one-dimensional moving magnet.
5. The multi-dimensional magnetic negative-stiffness mechanism according to claim 4 , wherein magnets for stacking in the one-dimensional negative-stiffness magnetic group are all long rectangular bodies with square cross sections.
6. A multi-dimensional magnetic negative-stiffness vibration isolation system, comprising: a positive-stiffness mechanism and the multi-dimensional magnetic negative-stiffness mechanism according to claim 1 , wherein
the positive-stiffness mechanism comprises an X-direction positive-stiffness component, a Z-direction positive-stiffness component, and a Y-direction positive-stiffness component, which are respectively supported between the vibration isolated body and the mounting base along an X-direction, a Z-direction, and a Y-direction.
7. The multi-dimensional magnetic negative-stiffness vibration isolation system according to claim 6 , wherein the X-direction positive-stiffness component, the Z-direction positive-stiffness component, and the Y-direction positive-stiffness component respectively comprise any one or more of a metal spring, a rubber structure, a metal-rubber composite structure, and a gas spring.
8. The multi-dimensional magnetic negative-stiffness vibration isolation system according to claim 7 , wherein the Z-direction positive-stiffness component comprises four Z-direction coil springs, which are symmetrically distributed at four corners between the vibration isolated body and the mounting base.
9. The multi-dimensional magnetic negative-stiffness vibration isolation system according to claim 7 , wherein the X-direction positive-stiffness component comprises two X-direction coil springs, which are symmetrically distributed along the X-direction on two sides of the vibration isolated object, and are fixedly connected onto the mounting base through an X-direction mounting column.
10. The multi-dimensional magnetic negative-stiffness vibration isolation system according to claim 7 , wherein the Y-direction positive-stiffness component comprises two Y-direction coil springs, which are symmetrically distributed along the Y-direction on two sides of the vibration isolation object, and are fixedly connected to the mounting base through a Y-direction mounting column.
11. The multi-dimensional magnetic negative-stiffness mechanism according to claim 2 , wherein the one-dimensional fixed magnets and the one-dimensional moving magnet are all formed by stacking a plurality of magnets, and in the magnets stacked on top of each other, magnetizing directions of adjacent magnets are opposite; and magnetizing directions of magnets on a same layer of two one-dimensional fixed magnets are the same and are opposite to magnetizing directions of magnets on a same layer of the one-dimensional moving magnet.
12. The multi-dimensional magnetic negative-stiffness mechanism according to claim 3 , wherein the one-dimensional fixed magnets and the one-dimensional moving magnet are all formed by stacking a plurality of magnets, and in the magnets stacked on top of each other, magnetizing directions of adjacent magnets are opposite; and magnetizing directions of magnets on a same layer of two one-dimensional fixed magnets are the same and are opposite to magnetizing directions of magnets on a same layer of the one-dimensional moving magnet.