# US 9,038,460 B2 · Inertial unit with several detection axes > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,038,460 B2 - Document ID: US9038460B2 - Status: Granted - Kind: B2 - Application number: 13/459,592 - Filed: 2012-04-30 - Published: 2012-11-08 - Granted: 2015-05-26 - Earliest claimed: 2011-05-02 - Assignees: Commissariat A L'energie Atomique E Aux Energies Alternatives - Applicants: Arnaud Walther - Inventors: Arnaud Walther - Web page: https://patentgrep.com/patent/US9038460B2 ## CPC - G01P 15/08: with conversion into electric or magnetic values - G01C 19/5712: the devices involving a micromechanical structure - G01C 19/5747: each sensing mass being connected to a driving mass, e.g. driving frames - G01P 15/18: in two or more dimensions - G01P: MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT (measuring or recording blood flow A61B5/02, A61B8/06; monitoring speed or deceleration of electrically-propelled vehicles B60L3/00; vehicle lighting systems adapted to indicate speed B60Q1/54; determining position or course in navigation, measuring ground distance in geodesy or surveying G01C; combined measuring devices for measuring two or more variables of movement G01C23/00; measuring velocity of sound G01H; measuring velocity of light G01J7/00; measuring direction or velocity of solid objects by reception or emission of radiowaves or other waves and based on propagation effects, e.g. Doppler effect, propagation time, direction of propagation, G01S; measuring speed of nuclear radiation G01T; measuring acceleration of gravity G01V; {measuring or recording the speed of trains B61L23/00; speed indicators incorporated in motor vehicles B60K35/00; measuring frequency or phase G01R; traffic control G08G}) - G01C: MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY (measuring liquid level G01F; radio navigation, determining distance or velocity by use of propagation effects, e.g. Doppler effects, propagation time, of radio waves, analogous arrangements using other waves G01S) ## Abstract Inertial unit for the measurement of accelerations and/or rotations comprising four sensors, spread out on two intersecting axes, each sensor comprising two inertial masses, each inertial mass comprising a moveable excitation part and a moveable detection part, the moveable excitation parts of a sensor being separate from those of the other sensors, said unit also comprising means for exciting the excitation parts of the sensors and means for detecting the movement of the detection parts, the two inertial masses of each sensor) being mechanically coupled, the four sensors being coupled by elastically deformable mechanical coupling means and able to transmit the excitation vibrations from one axis to the other. ## Claims ### Claim 1 An inertial unit for the measurement of accelerations and/or rotations comprising: at least four sensors, at least one of which is an accelerometer, distributed by pairs on at least two intersecting axes, including a first pair of sensors on a first axis and a second pair of sensors on a second axis, the second axis intersecting the first axis, each sensor comprising two inertial masses, each inertial mass comprising a moveable excitation part and a moveable detection part, the moveable excitation parts of a sensor being separate from those of the other sensors, the two inertial masses of each sensor being mechanically coupled by an intra-sensor coupling structure, excitation means for exciting the excitation parts of the sensors and detection means for detecting the movement of the detection parts, a control unit to control the excitation means and to control the detection means, a mechanical inner-sensor coupling structure between the four sensors, said inner-sensor coupling structure being elastically deformable and able to transmit the excitation vibrations from one axis to the other, wherein at least one of the intra-sensor coupling structures is a strong coupling means. ### Claim 2 (depends on 1) The inertial unit according to claim 1, in which all of said intra-sensor coupling structures are strong coupling means. ### Claim 3 (depends on 1) The inertial unit according to claim 1, in which said inner-sensor coupling structures are situated at the intersection of the axes bearing the two pairs of sensors, the two sensors of each pair being arranged on either side of said inner-sensor coupling structure. ### Claim 4 (depends on 1) The inertial unit according to claim 1, in which the at least two axes are perpendicular. ### Claim 5 (depends on 1) The inertial unit according to claim 1, in which the inner-sensor coupling structure is a strong coupling structure. ### Claim 6 (depends on 1) The inertial unit according to claim 1, in which the inner-sensor coupling structure is connected to the excitation part of one of the masses of each sensor. ### Claim 7 (depends on 1) The inertial unit according to claim 1, in which the inner-sensor coupling structure comprises an assembly of beams comprising at least one closed pattern. ### Claim 8 (depends on 7) The inertial unit according to claim 7, in which the closed pattern has the shape of a diamond, each top of said diamond being connected to a mass of a sensor. ### Claim 9 (depends on 1) The inertial unit according to claim 1, in which the intra-sensor coupling structures connect the two excitation parts of each sensor. ### Claim 10 (depends on 1) The inertial unit according to claim 1, in which the excitation part of each sensor is excitable in a single direction. ### Claim 11 (depends on 1) The inertial unit according to claim 1, comprising one or more gyrometers and/or one or more accelerometers, said at least gyrometer and/or accelerometer being able to measure a rotation and/or an acceleration along an axis called a detection axis. ### Claim 12 (depends on 11) The inertial unit according to claim 11, comprising a rigid rod in rotation around an axis orthogonal to the detection axis, said rigid rod connecting the two detection parts of the masses of the accelerometer. ### Claim 13 (depends on 11, 12) The inertial unit according to claim 11 or 12, the intra-sensor coupling structure between two masses of a gyrometer forming a strong coupling in antiphase, and the intra-sensor coupling structure between two masses of an accelerometer forming a strong coupling in phase. ### Claim 14 (depends on 13) The inertial unit according to claim 13, in which the intra-sensor coupling structure in antiphase comprises a closed assembly of beams. ### Claim 15 (depends on 13) The inertial unit according to claim 13, in which the intra-sensor coupling structure in phase comprises a rigid connection, the two masses of a same accelerometer acting as a single mass. ### Claim 16 (depends on 12) The inertial unit according to claim 12, the intra-sensor coupling structure between two masses of a gyrometer forming a strong coupling in antiphase, and the intra-sensor coupling structure between two masses of an accelerometer forming a strong coupling in phase. ### Claim 17 (depends on 16) The inertial unit according to claim 16, in which the intra-sensor coupling structure in antiphase comprises a closed assembly of beams. ### Claim 18 (depends on 16, 17) The inertial unit according to claim 16 or 17, in which the intra-sensor coupling structure in phase comprises a rigid connection, the two masses of a same accelerometer acting as a single mass. ### Claim 19 (depends on 11) The inertial unit according to claim 11, in which the gyrometers(s) comprise a rigid rod in rotation around the detection axis around which the rotation is to be detected connecting the detection parts of the inertial masses. ### Claim 20 (depends on 1) The inertial unit according to claim 1, in which at least one of the sensors is replaced by an object not supplying a measurement on the acceleration or the rotation and ensuring a balancing of the inertial unit. ### Claim 21 (depends on 1) The inertial unit according to claim 1, comprising three pairs of sensors, the sensors of each pair being aligned on an axis , two of the axes being parallel and the other axis being intersecting to the two parallel axes, a first inner-sensor coupling structure being provided at the level of each intersection of one of the axes parallel with the other axis and a second inner-sensor coupling structure being provided between the first inner-sensor coupling structure. ### Claim 22 (depends on 21) The inertial unit according to claim 21, comprising three gyrometers and three accelerometers, the three gyrometers being connected directly to the first inner-sensor coupling structure different from the first inner-sensor coupling structure to which are connected directly the three accelerometers. ### Claim 23 (depends on 1) The inertial unit according to claim 1, comprising eight sensors, the inner-sensor coupling means comprising an assembly of eight patterns in juxtaposed diamond shape, the patterns being connected by one of their tops in a point constituting a centre of symmetry of the coupling structure, so as to have patterns opposite and aligned two by two, the tops of the opposite patterns at the centre of symmetry being intended to be each integral with a mass of eight sensors. ### Claim 24 (depends on 1) The inertial unit according to claim 1, in which the excitation means are of electrostatic, piezoelectric or magnetic type and the detection means are of capacitive, piezoelectric, magnetic or piezoresistive type. ### Claim 25 (depends on 1) The inertial unit according to claim 1, in which the detection means are chosen of same type for all of the sensors. ### Claim 26 (depends on 1) The inertial unit according to claim 1, in which the control unit comprises a single control loop in excitation for all of sensors and means for detecting the displacement of the detection parts. ### Claim 27 (depends on 1) The inertial unit according to claim 1, in which the control unit comprises means for reading the detection means of the different sensors by time division multiplexing. ### Claim 28 (depends on 1) The inertial unit according to claim 1, in which the strong coupling means mechanically couples two inertial masses of the accelerometer such that the two inertial masses of the accelerometer move with a same amplitude. ### Claim 29 (depends on 28) The inertial unit according to claim 28, in which the strong coupling means includes a rigid rod connecting the two inertial masses of the accelerometer. ### Claim 30 (depends on 1) The inertial unit according to claim 1, in which at least one of the four sensors is a gyroscope and the strong coupling means mechanically couples two inertial masses of the gyroscope such that the two inertial masses of the gyroscope move apart or closer together in phase along a same axis and with a same amplitude. ### Claim 31 (depends on 30) The inertial unit according to claim 30, in which the strong coupling means includes a rigid rod connecting the two inertial masses of the gyroscope.