# US 12,601,612 B2 · Vehicle system including sensor unit for detecting magnetic marker laid on a road > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,601,612 B2 - Document ID: US12601612B2 - Status: Granted - Kind: B2 - Application number: 18/289,893 - Filed: 2022-05-11 - Published: 2024-07-25 - Granted: 2026-04-14 - Earliest claimed: 2021-05-12 - Assignees: Aichi Steel Corporation - Applicants: Aichi Steel Corporation - Inventors: Michiharu Yamamoto; Tomohiko Nagao; Hitoshi Aoyama - Web page: https://patentgrep.com/patent/US12601612B2 ## CPC - G01D 5/14: influencing the magnitude of a current or voltage - G05D 1/646: Following a predefined trajectory, e.g. a line marked on the floor or a flight path - G01B 7/003: {for measuring position, not involving coordinate determination (coordinate measuring G01B7/004)} - G05D 1/244: using passive navigation aids external to the vehicle, e.g. markers, reflectors or magnetic means - G05D 2107/13: Spaces reserved for vehicle traffic, e.g. roads, regulated airspace or regulated waters - G05D 2109/10: Land vehicles - G05D 2111/30: Radio signals - G01D: MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR - G05D: SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES - G01B: MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS ## Abstract A vehicle system includes a sensor unit including magnetic sensors for detecting a magnetic marker and non-contact displacement sensors which measure a displacement relative to a road surface where the magnetic marker is laid, a processing circuit which performs detection process for detecting the magnetic marker by processing a magnetic measurement value by the plurality of magnetic sensors, and a switching circuit which switches the detection process in accordance with displacement measurement values by the non-contact displacement sensors. By switching the detection process in accordance with the displacement measurement values by the non-contact displacement sensors, the magnetic marker can be detected with high reliability. ## Claims ### Claim 1 A sensor unit to be attached to a movable body to detect a magnetic marker, the sensor unit comprising: at least one magnetic sensor which measures magnetism acting from the magnetic marker; and at least one non-contact displacement sensor which measures a displacement of the movable body relative to a surface where the magnetic marker is laid, wherein the at least one non-contact displacement sensor includes a light source which irradiates light onto the surface, an imager which captures images of the surface in synchronism with light emitting operation of the light source, and a circuit configured to calculate the displacement by identifying an amount of shift which results in a highest match between two temporally successive images when one of the two temporally successive images is positionally shifted by the amount of shift and compared with the other of the two temporally successive images. ### Claim 2 (depends on 1) The sensor unit in claim 1, wherein the at least one magnetic sensor is a plurality of magnetic sensors, the at least one non-contact displacement sensor is a plurality of non-contact displacement sensors, the plurality of magnetic sensors is arrayed on a single straight line, and at least two of the plurality of non-contact displacement sensors are arranged on a straight line parallel to the single straight line. ### Claim 3 (depends on 2) The sensor unit in claim 2, further comprising: a circuitry configured to perform a detection process for detecting the magnetic marker by processing magnetic measurement values measured by the plurality of magnetic sensors, and switch the detection process in accordance with displacement measurement values measured by the plurality of non-contact displacement sensors, wherein the detection process includes a process to which time-series magnetic measurement values measured by one magnetic sensor among the plurality of magnetic sensors are subjected, and the circuitry is further configured to identify a displacement of each magnetic sensor configuring the plurality of magnetic sensors based on the displacement measurement values measured by the plurality of non-contact displacement sensors, and individually change, for the each magnetic sensor, the process to which the time-series magnetic measurement values are subjected, in accordance with the displacement of the each magnetic sensor. ### Claim 4 (depends on 3) The sensor unit in claim 3, wherein the detection process includes a filter process on a signal indicating a temporal or spatial change of the magnetic measurement values measured by the plurality of magnetic sensors or operation values based on the magnetic measurement values, and the circuitry is further configured to switch the detection process by changing filter characteristics of the filter process in accordance with the displacement measurement values measured by the plurality of non-contact displacement sensors. ### Claim 5 (depends on 2) The sensor unit in claim 2, further comprising: circuitry configured to acquire, in parallel, magnetic measurement values measured by the plurality of magnetic sensors, identify a displacement of each magnetic sensor configuring the plurality of magnetic sensors based on the displacement measurement values measured by the plurality of non-contact displacement sensors, and individually change, for the each magnetic sensor, a temporal interval for acquiring the magnetic measurement values in accordance with the displacement of the each magnetic sensor. ### Claim 6 (depends on 5) The sensor unit in claim 5, wherein the circuitry is further configured to change the temporal interval for acquiring the magnetic measurement values so that positions where the magnetic measurement values have been acquired can be arrayed with a constant distance gap. ### Claim 7 (depends on 2) The sensor unit in claim 2, further comprising: circuitry configured to perform a detection process for detecting the magnetic marker by processing magnetic measurement values measured by the plurality of magnetic sensors, and switch the detection process in accordance with displacement measurement values measured by the plurality of non-contact displacement sensors. ### Claim 8 (depends on 1) The sensor unit in claim 1, wherein the at least one magnetic sensor is a plurality of magnetic sensors, the at least one non-contact displacement sensor is a plurality of non-contact displacement sensors, the plurality of magnetic sensors is two-dimensionally arrayed, and at least two of the plurality of non-contact displacement sensors are arranged at different positions. ### Claim 9 (depends on 1) The sensor unit in claim 1, wherein the at least one magnetic sensor is a plurality of magnetic sensors, the at least one non-contact displacement sensor is a plurality of non-contact displacement sensors, and the plurality of non-contact displacement sensors is respectively disposed to the plurality of magnetic sensors so that each of the plurality of non-contact displacement sensors is able to individually measure a displacement of each of the plurality of magnetic sensors relative to the surface. ### Claim 10 (depends on 1) The sensor unit in claim 1, further comprising: circuitry configured to perform a detection process for detecting the magnetic marker by processing a magnetic measurement value measured by the at least one magnetic sensor, and switch the detection process in accordance with a displacement measurement value measured by the at least one non-contact displacement sensor. ### Claim 11 (depends on 10) The sensor unit in claim 10, wherein the detection process includes a filter process on a signal indicating a temporal or spatial change of the magnetic measurement value measured by the at least one magnetic sensor or an operation value based on the magnetic measurement value, and the circuitry is further configured to switch the detection process by changing filter characteristics of the filter process in accordance with the displacement measurement value measured by the at least one non-contact displacement sensor. ### Claim 12 A sensor unit to be attached to a movable body to detect a magnetic marker, the sensor unit comprising: at least one magnetic sensor which measures magnetism acting from the magnetic marker; at least one non-contact displacement sensor which measures a displacement of the movable body relative to a surface where the magnetic marker is laid; and circuitry configured to acquire magnetic measurement values measured by the at least one magnetic sensor, and change a temporal interval for acquiring the magnetic measurement values in accordance with a displacement measurement value measured by the at least one non-contact displacement sensor. ### Claim 13 (depends on 12) The sensor unit in claim 12, wherein the circuitry is further configured to change the temporal interval for acquiring the magnetic measurement values so that positions where the magnetic measurement values have been acquired can be arrayed with a constant distance gap. ### Claim 14 A system to detect a magnetic marker, the system comprising: a movable body; and a sensor unit attached to the movable body, wherein the sensor unit includes at least one magnetic sensor which measures magnetism acting from the magnetic marker, and at least one non-contact displacement sensor which measures a displacement of the movable body relative to a surface where the magnetic marker is laid, wherein the at least one non-contact displacement sensor includes a light source which irradiates light onto the surface, an imager which captures images of the surface in synchronism with light emitting operation of the light source, and a circuit configured to calculate the displacement by identifying an amount of shift which results in a highest match between two temporally successive images when one of the two temporally successive images is positionally shifted by the amount of shift and compared with the other of the two temporally successive images. ### Claim 15 (depends on 14) The system in claim 14, further comprising: circuitry configured to perform a detection process for detecting the magnetic marker by processing a magnetic measurement value measured by the at least one magnetic sensor, and switch the detection process in accordance with the displacement measured by the at least one non-contact displacement sensor. ### Claim 16 (depends on 15) The system in claim 15, wherein the detection process includes a filter process on a signal indicating a temporal or spatial change of the magnetic measurement value measured by the at least one magnetic sensor or an operation value based on the magnetic measurement value, and the circuitry is further configured to switch the detection process by changing filter characteristics of the filter process in accordance with a displacement measurement value measured by the at least one non-contact displacement sensor. ### Claim 17 (depends on 16) The system in claim 16, wherein the movable body is a vehicle traveling a road, and the circuitry is further configured to switch the detection process in accordance with a type of the road where the movable body travels. ### Claim 18 (depends on 15) The system in claim 15, wherein the movable body is a vehicle traveling a road, and the circuitry is further configured to switch the detection process in accordance with a type of the road where the movable body travels. ### Claim 19 (depends on 14) The system in claim 14, wherein the sensor unit further includes circuitry configured to acquire magnetic measurement values measured by the at least one magnetic sensor, and change a temporal interval for acquiring the magnetic measurement values in accordance with a displacement measurement value measured by the at least one non-contact displacement sensor. ### Claim 20 (depends on 19) The system in claim 19, wherein the circuitry is further configured to change the temporal interval for acquiring the magnetic measurement values so that positions where the magnetic measurement values have been acquired can be arrayed with a constant distance gap.