# US 12,014,855 B1 · Haptic actuator based on nutation structure using squeeze mode of magneto-rheological fluid > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,014,855 B1 - Document ID: US12014855B1 - Status: Granted - Kind: B1 - Application number: 18/175,332 - Filed: 2023-02-27 - Granted: 2024-06-18 - Earliest claimed: 2023-02-27 - Assignees: Korea University of Technology and Education Industry-University Cooperation Foundation - Applicants: Korea University Of Technology And Education Industry-University Cooperation Foundation - Inventors: Yong Hae Heo; Hyun-U Ko; Seok-Han Lee; Seang Ho Kim; Sang-Youn Kim - Web page: https://patentgrep.com/patent/US12014855B1 ## CPC - H01F 13/00: Apparatus or processes for magnetising or demagnetising ({devices for holding workpieces using magnetic or electric force acting directly on the workpieces B23Q3/15} ; for degaussing ships B63G9/06; for clocks or watches G04D9/00; {recording or erasing of information on magnetic record carriers G11B5/00} ; demagnetising arrangements for colour television H04N9/29) - H01F 1/447: {characterised by magnetoviscosity, e.g. magnetorheological, magnetothixotropic, magnetodilatant liquids (electrorheological fluids C10M171/001)} - H01F 7/20: without armatures (cores H01F3/00; coils H01F5/00 {; shaping metal by applying magnetic forces B21D26/14; electromagnets specially adapted for NMR applications G01R33/381}) - H01F: MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES ## Abstract The present invention relates to a haptic actuator based on a nutation structure using a squeeze mode of a magneto-rheological fluid, which compresses a magneto-rheological fluid (MR fluid) by using a rotary body capable of performing a rotary motion based on a nutation structure, thereby generating a sustainable rotational resistance force by using a squeeze mode and a flow mode of the MR fluid. ## Claims ### Claim 1 A haptic actuator based on a nutation structure using a squeeze mode of a magneto-rheological fluid, the haptic actuator comprising: an actuator housing 110 having an interior filled with a magneto-rheological fluid (MR fluid); a rotary body 120 configured to compress the MR fluid by rotating in the actuator housing 110; and a coil 130 provided on an inner surface of the actuator housing 110 and configured to generate a magnetic field by applied electric current, wherein a rotational resistance force is generated in the MR fluid as the rotary body 120 rotates and compresses the MR fluid activated by the magnetic field generated by the coil 130. ### Claim 2 (depends on 1) The haptic actuator of claim 1, wherein the actuator housing 110 is provided to be divided into an upper housing 111 and a lower housing 112. ### Claim 3 (depends on 2) The haptic actuator of claim 2, wherein the upper housing 111 has a vertical through-hole 111a that a shaft 121 extending from one side of the rotary body 120 penetrates upward. ### Claim 4 (depends on 3) The haptic actuator of claim 3, wherein an O-ring 113 is provided in the vertical through-hole 111a to prevent the MR fluid in the actuator housing 110 from leaking, and a bearing 114 is provided in the vertical through-hole 111a to support the shaft 121 and reduce frictional resistance when the shaft 121 rotates. ### Claim 5 (depends on 1) The haptic actuator of claim 1, wherein the rotary body 120 comprises: a rotary sphere 122 provided at a central portion of the actuator housing 110 and configured to rotate by means of a shaft 121; and a circular compression plate 123 protruding outward from the rotary sphere 122 and configured to compress the MR fluid in a state in which the circular compression plate 123 is inclined at a predetermined angle. ### Claim 6 (depends on 5) The haptic actuator of claim 5, wherein the circular compression plate 123 has one or more flow paths 123a through which the compressed MR fluid flows in a vertical direction. ### Claim 7 (depends on 6) The haptic actuator of claim 6, wherein when the rotary sphere 122 rotates, the circular compression plate 123 inclined at the predetermined angle repeatedly compresses the MR fluid, such that a rotational resistance force in a flow mode is additionally generated as the MR fluid flows through the flow path 123a. ### Claim 8 (depends on 5) The haptic actuator of claim 5, wherein when the rotary sphere 122 rotates, the circular compression plate 123 inclined at the predetermined angle repeatedly compresses the MR fluid, such that a rotational resistance force is consistently generated by the MR fluid. ### Claim 9 (depends on 1) The haptic actuator of claim 1, wherein the coil 130 is an electropermanent magnet (EPM). ### Claim 10 (depends on 9) The haptic actuator of claim 9, wherein the electropermanent magnet comprises: a circular alnico magnet provided along an edge of an inner surface of the actuator housing 110; a circular neodymium magnet provided on an inner surface of the alnico magnet while defining a concentric circle; and a solenoid coil wound around the alnico magnet and the neodymium magnet.