# US 6,969,025 B1 · Servo actuation systems > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 6,969,025 B1 - Document ID: US6969025B1 - Status: Granted - Kind: B1 - Application number: 07/421,629 - Filed: 1989-10-06 - Granted: 2005-11-29 - Earliest claimed: 1988-10-24 - Assignees: Mbda UK Limited - Inventors: John F. Bugge; Kenneth C. Goulding; Anthony Machell - Web page: https://patentgrep.com/patent/US6969025B1 ## CPC - G05D 3/12: using feedback - G05B 2219/34013: Servocontroller - G05B 2219/34027: Dual servo controller, for two motors - G05B 2219/42097: Dual mode servo, slow and precise, quick and coarse movement - G05D: SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES - G05B: CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS (systems for controlling or regulating non-electric variables G05D; systems for regulating electric or magnetic variables G05F; control devices or systems insofar as characterised by mechanical features only G05G) ## Abstract A dual servo system for a seeker actuator comprises a seeker head gimballed on a platform and driven in the pitch and yaw senses by respective fast, i.e. high bandwidth low ambit, servo sub-systems, the platform being pivotally mounted with respect to a base and driven in the pitch and yaw senses by respective slow, i.e. low bandwidth high ambit, servo systems. The pivotal mounting between the platform and the base is configured to provide a spherical bearing of relatively large area (typically about 85° solid angle) to provide good resistance to high acceleration loads. ## Claims ### Claim 1 A dual servo system comprising: a support means; platform means mounted for movement in a given sense with respect to said support means; base means; said support means being mounted for movement in substantially the same sense with respect to said base means; first drive means for effecting small displacements of said platform means relative to said support means; second drive means for effecting large displacements of said support means relative to said base means; and common control means, responsive to an input signal, for controlling said first and second drive means to orient said platform means in accordance with said input signal. ### Claim 2 A seeker actuation system for a projectile including: base means for attachment to a projectile, mounting means supported for movement in at least one sense, sensor means mounted for movement with respect to the mounting means in said at least one sense, first drive means for effecting movement of said mounting means relative to said base means in said at least one sense, second drive means for effecting movement of said sensor relative to said mounting means in said at least one sense, and common means responsive to an input demand signal to control each of said first and second drive means to move said sensor to a required position, one of said drive means being capable of effecting movement in a relatively large locus of movement and the other of said drive means being capable of effecting movement in a relatively small locus of movement. ### Claim 3 (depends on 2) A seeker actuation system according to claim 2, wherein said first drive means is capable of effecting movement through a relatively large arc. ### Claim 4 (depends on 3) A seeker actuation system according to claim 3, wherein said sensor means is mounted for pitch and yaw movement about a pivotal point and said mounting means is mounted for pitch and yaw movement about substantially the same pivotal point, and the system includes first and second yaw drive means and first and second pitch drive means for effecting movements in the pitch and yaw senses respectively. ### Claim 5 (depends on 2) A seeker actuation system according to claim 2, wherein said sensor means is mounted on said mounting means by means of a gimbal arrangement and the second drive means comprises a linear force motor arranged between the sensor means and the mounting means. ### Claim 6 (depends on 2) A seeker actuation system according to claim 2, wherein the second drive means includes a rack and pinion arrangement. ### Claim 7 (depends on 2) A seeker actuation system according to claim 2, wherein the mounting means and the base means have complementary generally spherical bearing surfaces for supporting the mounting means to pivot in at least one sense about a pivot point. ### Claim 8 (depends on 2) A seeker actuation system according to claim 2, wherein the mounting means is connected to the support means by translation plate means, the translation plate means having a concave spherical surface for engaging a complementary surface on the mounting means and a generally concentric convex spherical surface for engaging a complementary convex surface on the base means. ### Claim 9 A servo system comprising: a platform mounted for movement; and a servo loop controlling movement of said platform in accordance with an input signal, said servo loop including: first drive means for effecting relatively large displacements of said platform within a relatively low bandwidth; second drive means for effecting relatively small displacements of said platform within a relatively high bandwidth; and common control means, responsive to said input signal, for controlling said first and second drive means. ### Claim 10 A dual servo system comprising: a support means; platform means mounted for movement in a given sense with respect to said support means; base means; said support means being mounted for movement in substantially the same sense with respect to said base means; first drive means for effecting small displacements of said platform means relative to said support means; second drive means for effecting large displacements of said support means relative to said base means; and control means, separate from said first and second drive means and responsive to an input signal, for controlling said first and second drive means to orient said platform means in accordance with said input signal. ### Claim 11 A seeker actuation system for a projectile including: base means for attachment to a projectile, mounting means supported for movement in at least one sense, sensor means mounted for movement with respect to the mounting means in said at least one sense, first drive means for effecting movement of said mounting means relative to said base means in said at least one sense, second drive means for effecting movement of said sensor relative to said mounting means in said at least one sense, and means, separate from said first and second drive means and responsive to an input demand signal, for controlling said first and second drive means to move said sensor to a required position, one of said drive means being capable of effecting movement in a relatively large locus of movement and the other of said drive means being capable of effecting movement in a relatively small locus of movement. ### Claim 12 (depends on 11) A seeker actuation system according to claim 11, wherein said first drive means is capable of effecting movement through a relatively large arc. ### Claim 13 (depends on 12) A seeker actuation system according to claim 12, wherein said sensor means is mounted for pitch and yaw movement about a pivotal point and said mounting means is mounted for pitch and yaw movement about substantially the same pivotal point, and the system includes first and second yaw drive means and first and second pitch drive means for effecting movement in the pitch and yaw senses respectively. ### Claim 14 A servo system comprising: a platform mounted for movement; and a servo loop controlling movement of said platform in accordance with an input signal, said servo loop including: first drive means for effecting relatively large displacements of said platform within a relatively low bandwidth; second drive means for effecting relatively small displacements of said platform within a relatively high bandwidth; and control means, separate from said first and second drive means and responsive to said input signal, for controlling said first and second drive means.