MEMS gyroscope with enhanced robustness against vibrations and reduced dimensions
MEMS gyroscope, having a first movable mass configured to move with respect to a fixed structure along a first drive direction and along a first sense direction, transverse to the first drive direction; a first drive assembly, coupled to the first movable mass and configured to generate a first alternate drive movement; a first drive elastic structure, coupled to the first movable mass and to the first drive assembly, rigid in the first drive direction and compliant in the first sense direction; a second movable mass, configured to move with respect to the fixed structure in a second drive direction parallel to the first drive direction and in a second sense direction parallel to the first sense direction; a second drive assembly, coupled to the second movable mass and configured to generate a second alternate drive movement in the second drive direction; and a second drive elastic structure, coupled to the second movable mass and to the second drive assembly, rigid in the second drive direction and compliant in the second sense direction.
1 . A micro electro-mechanical systems (MEMS) gyroscope, comprising:
a fixed structure;
a first movable mass, the first movable mass being configured to move with respect to the fixed structure along a first drive direction and along a first sense direction, transverse to the first drive direction;
a first drive assembly, coupled to the first movable mass and configured to generate a first alternate drive movement in the first drive direction;
a first drive elastic structure, coupled to the first movable mass and to the first drive assembly, the first drive elastic structure being rigid in the first drive direction, being configured to transfer the first alternate drive movement to the first movable mass and being compliant in the first sense direction;
a second movable mass, the second movable mass being configured to move with respect to the fixed structure in a second drive direction parallel to the first drive direction and in a second sense direction parallel to the first sense direction;
a second drive assembly, coupled to the second movable mass and configured to generate a second alternate drive movement in the second drive direction, the second alternate drive movement being in phase opposition with respect to the first alternate drive movement; and
a second drive elastic structure, coupled to the second movable mass and to the second drive assembly, the second drive elastic structure being rigid in the second drive direction, configured to transfer the second alternate drive movement to the second movable mass and compliant in the second sense direction;
a third movable mass, the third movable mass configured to move with respect to the fixed structure in a third drive direction, parallel to the first drive direction, and in a third sense direction, transverse to the third drive direction and to the first sense direction;
a third drive elastic structure, coupled to the third movable mass and to the first drive assembly, the third drive elastic structure rigid in the third drive direction, configured to transfer the first alternate drive movement to the third movable mass and compliant in the third sense direction;
a fourth movable mass, the fourth movable mass configured to move with respect to the fixed structure in a fourth drive direction, parallel to the first drive direction, and in a fourth sense direction, parallel to the third sense direction;
a third drive assembly, coupled to the fourth movable mass and configured to generate a fifth alternate drive movement in the fourth drive direction, the fifth alternate drive movement in phase opposition with the first alternate drive movement; and
a fourth drive elastic structure, coupled to the fourth movable mass and the third drive assembly, the fourth drive elastic structure rigid in the fourth drive direction, configured to transfer the fifth alternate drive movement to the fourth movable mass and compliant in the fourth sense direction.
2 . The MEMS gyroscope according to claim 1 , further comprising:
a first sense elastic system, coupling the first movable mass to the fixed structure and configured to allow movements of the first movable mass with respect to the fixed structure in the first drive direction and in the first sense direction;
a second sense elastic system, coupling the second movable mass to the fixed structure and configured to allow movements of the second movable mass with respect to the fixed structure in the second drive direction and in the second sense direction.
3 . The MEMS gyroscope according to claim 2 , wherein:
the first sense elastic system comprises a first sense mass, a first sense elastic structure and a first anchoring elastic structure, the first sense elastic structure being coupled between the first movable mass and the first sense mass, compliant in the first drive direction and rigid in the first sense direction, the first anchoring elastic structure being coupled between the first sense mass and the fixed structure and compliant in the first sense direction;
the second sense elastic system comprises a second sense mass, a second sense elastic structure and a second anchoring elastic structure, the second sense elastic structure being coupled between the second movable mass and the second sense mass, compliant in the second drive direction and rigid in the second sense direction, the second anchoring elastic structure being coupled between the second sense mass and the fixed structure and compliant in the second sense direction; and
the first sense mass and the second sense mass are coupled to respective position sense structures.
4 . The MEMS gyroscope according to claim 3 , further comprising:
a first bridge element coupling the first and the second sense masses, the first bridge element coupled to the fixed structure and rotatable around a first vertical axis transverse to the first drive direction and to the first sense direction.
5 . The MEMS gyroscope according to claim 1 , wherein the first and the second movable masses are a yaw sense portion.
6 . The MEMS gyroscope according to claim 5 , wherein the third movable mass, the third drive elastic structure, the fourth movable mass, the third drive assembly, and the fourth drive elastic structure are a pitch/roll sense portion.
7 . The MEMS gyroscope according to claim 6 , wherein the pitch/roll sense portion further comprises:
a fifth movable mass, the fifth movable mass configured to move with respect to the fixed structure in a fifth drive direction, parallel to the first drive direction, and in a fifth sense direction, parallel to the third sense direction;
a fourth drive assembly, coupled to the fifth movable mass and configured to generate a sixth alternate drive movement in the fifth drive direction, the sixth alternate drive movement in phase with the first alternate drive movement;
a fifth drive elastic structure, coupled to the fifth movable mass and to the fourth drive assembly, the fifth drive elastic structure rigid in the fifth drive direction, configured to transfer the sixth alternate drive movement to the fifth movable mass and compliant in the fifth sense direction;
an sixth movable mass, the sixth movable mass configured to move with respect to the fixed structure in an sixth drive direction, parallel to the first drive direction, and in an sixth sense direction, parallel to the third sense direction;
a fifth drive assembly, coupled to the sixth movable mass and configured to generate a seventh alternate drive movement in the sixth drive direction, the seventh alternate drive movement in phase with the first alternate drive movement; and
an sixth drive elastic structure, coupled to the sixth movable mass and the fourth drive assembly, the sixth drive elastic structure rigid in the sixth drive direction, configured to transfer the seventh alternate drive movement to the sixth movable mass and compliant in the sixth sense direction.
8 . The MEMS gyroscope according to claim 7 , wherein the third and the fourth movable mass are joined to each other and monolithic and wherein the fifth and the sixth movable masses are joined to each other and monolithic.
9 . The MEMS gyroscope according to claim 7 , further comprising an anchoring elastic structure elastically coupling the third, the fourth, the fifth and the sixth movable masses.
10 . The MEMS gyroscope according to claim 7 , further comprising:
a seventh movable mass, the seventh movable mass configured to move with respect to the fixed structure in a seventh drive direction, parallel to the first drive direction, and in a seventh sense direction, parallel to the third sense direction;
a seventh drive elastic structure, coupled to the seventh movable mass and the second drive assembly, the seventh drive elastic structure rigid in the second drive direction, configured to transfer the second alternate drive movement to the seventh movable mass and compliant in the seventh sense direction; and
a bridge element extending between the third, the fourth and the seventh movable masses, the bridge element coupled to the fixed structure and rotatable around a second vertical axis, transverse to the first drive direction and parallel to the third sense direction.
11 . A gyroscope, comprising:
a support;
a first drive assembly elastically coupled to the support, the first drive assembly including a first frame including a base and first and second arms extending from the base of the first frame;
a first mass positioned between the first and second arms of the first frame, the first mass elastically coupled to the first arm of the first frame by a first spring and to the second arm of the first frame by a second spring, the first mass configured to move with respect to the support along a first drive direction and along a first sense direction that is transverse to the first drive direction;
a second drive assembly elastically coupled to the support, the second drive assembly including a second frame including a base and first and second arms extending from the base of the second frame;
a second mass positioned between the first and second arms of the second frame, the second mass elastically coupled to the first arm of the second frame by a third spring and to the second arm of the second frame by a fourth spring, the second mass configured to move with respect to the support in a second drive direction parallel to the first drive direction and in a second sense direction parallel to the first sense direction, the first arm of the first frame elastically coupled to the first arm of the second frame by a fifth spring, the second arm of the first frame elastically coupled to the second arm of the second frame by a sixth spring; and
a sense mass elastically coupled to the support and elastically coupled between the first mass and the second mass.
12 . The gyroscope of claim 11 , wherein the sense mass is configured to rotate around a rotation axis.
13 . A gyroscope, comprising:
a fixed structure;
a first movable mass configured to move along a first drive direction and along a first sense direction, transverse to the first drive direction;
a first drive assembly elastically coupled to the fixed structure and the first movable mass, the first drive assembly configured to generate a first alternate drive movement in the first drive direction, the first drive assembly including a first frame including a base and first and second arms extending from the base of the first frame, the first movable mass elastically coupled to the first arm of the first frame by a first spring and to the second arm of the first frame by a second spring;
a second movable mass configured to move in a second drive direction parallel to the first drive direction and in a second sense direction parallel to the first sense direction;
a second drive assembly elastically coupled to the fixed structure and the second movable mass, the second drive assembly configured to generate a second alternate drive movement in the second drive direction, the second drive assembly including a second frame including a base and first and second arms extending from the base of the second frame, the second movable mass elastically coupled to the first arm of the second frame by a third spring and to the second arm of the second frame by a fourth spring, the first arm of the first frame elastically coupled to the first arm of the second frame by a fifth spring, the second arm of the first frame elastically coupled to the second arm of the second frame by a sixth spring; and
a sense mass elastically coupled to the fixed structure, the first movable mass, and the second movable mass, the first movable mass being coupled to the second movable mass by the sense mass.