Rotary solenoid microactuator with drive coil

Abstract

Techniques, devices, and systems are disclosed that provide a rotary solenoid microactuator having a rotary solenoid core with dual magnetic drive coils and magnetic field focusing elements. In one or more examples, the rotary solenoid microactuator may have a spring return, while other examples may have two sets of drive coils that push and pull across each magnetic gap. The magnetic field focusing elements are operable to increase the magnetic field. The rotary solenoid microactuator is configured to expel a liquid medicament from a medication delivery device.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Patent Application No. 63 / 371,805, filed August 18, 2022, the entire contents of which are incorporated herein by reference in their entirety. [Background technology]

[0002] For wearable medical devices, their physical size is a major factor in the overall impact of treatment on the patient using them. One of the largest elements in a complex medical device (such as an insulin pump) is the pumping actuator, which provides the force necessary to deliver the therapeutic agent to the patient. To maintain a small device footprint, the design objective is to optimize the efficiency and performance of the actuator while providing the required power output.

[0003] As the dimensions of electromechanical actuators shrink, the relative proportion of active elements (magnets, coils, etc.) to packaging elements decreases, resulting in losses in both performance and efficiency.

[0004] The performance and efficiency loss can be attributed to the reduction in total magnetic flux due to the reduction in the dimensions of both the permanent magnet and the magnetic coil. Because volume is a cubic relationship (i.e., L x W x H), reducing each axis by half results in a final volume equal to 1 / 8 of the starting volume. However, less magnet volume results in less magnetic flux density inducing a force between the permanent magnet and the coil.

[0005] The required force / torque density required for pumps is often very high. Commercially available DC micromotors based on existing technology have little available torque, requiring mechanical advantage techniques (i.e., gear reduction) that add size, cost, and complexity to the actuator solution. Also, while rotary motors are designed to rotate continuously at fairly high speeds, pumping mechanisms are inherently prone to reciprocal motion, meaning additional translation is required.

[0006] Some solenoids address the problem of reciprocal motion by having bipolar action (on / off, push / pull, etc.), but tend to suffer from other challenges. A large magnetic field is required to generate a large output force. Solenoids can utilize the attractive force of a magnetic coil on a ferromagnetic plunger, but this is limited by the magnetic field strength of the coil (current) and the magnetic permeability of the plunger. Furthermore, in some implementations where a permanent magnet is added to the plunger or a ferromagnetic plunger is used, the magnetic field of the plunger can interact with the external electromagnetic field, leading to inadvertent insulin delivery, if or when the drug delivery device is exposed to an external magnetic field. This additional magnet can also increase the dimensions of the drug delivery device by increasing key dimensions, such as the outer diameter of the reservoir with the new coil.

[0007] Unfortunately, the typical configuration of a linear solenoid involves placing a plunger within the center of a coil of wire to generate a magnetic field within the coil. This configuration requires an increased coil diameter to accommodate the larger permanent magnet volume. Thus, the two elements are not complementary, resulting in further inefficiencies.

[0008] Looking at these issues together, it is possible to arrive at a clear problem statement for the optimization of force output, actuator size (volume), and electrical output.

[0009] It would be useful to have a small, low-cost microactuator with reciprocating motion and maximum output force for a given electrical input.

[0010] It would also be beneficial if a device or algorithm existed that utilized the provided data to customize insulin pump settings or algorithm parameters for an individual. Summary of the Invention

[0011] This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended as an aid in determining the scope of the claimed subject matter.

[0012] According to one example of the disclosed subject matter, a microactuator for a wearable medication delivery device can include a force transfer assembly, a drive coil, and a main structure. The force transfer assembly can include a first focusing element and a second focusing element, and the second focusing element can include a yoke. The drive coil can be operable to attract or repel the first focusing element and the second focusing element. The main structure can be configured to hold the force transfer assembly and the drive coil in alignment with each other.

[0013] In another example of a microactuator, a microactuator for a wearable medication delivery device is provided, the microactuator having a force transmission assembly, a first pair of drive coils, and a second pair of drive coils. The force transmission assembly has a magnet between a first focusing element and a second focusing element. The second focusing element has a yoke. Each drive coil of the first pair of drive coils is energized with an opposite magnetic polarity to the other drive coil to attract or repel the first focusing element and the second focusing element in a first direction. Each drive coil of the second pair of drive coils is energized with an opposite magnetic polarity to the other drive coil to attract or repel the first focusing element and the second focusing element in a second direction opposite the first direction. [Brief explanation of the drawings]

[0014] [Figure 1A] FIG. 1A shows an example of a microactuator in accordance with the disclosed subject matter. [Figure 1B] FIG. 1B shows an exploded view of the example microactuator of FIG. [Figure 2A] FIG. 2A shows a side view of the magnetic assembly of the microactuator. [Figure 2B] FIG. 2B shows an example of magnetic field lines in a fully assembled microactuator according to an embodiment of the disclosed subject matter. [Figure 3A] FIG. 3A shows a top view of the microactuator to illustrate an example of the theory of operation of the microactuator shown in FIGS. 1A to 2B. [Figure 3B] FIG. 3B shows a top view of the microactuator to illustrate an example of the theory of operation of the microactuator shown in FIGS. 1A to 2B. [Figure 4A] FIG. 4A shows a top view of an example of a rotary solenoid microactuator with a single drive coil. [Figure 4B] FIG. 4B shows a side view of an example of a rotary solenoid microactuator with a single drive coil. [Figure 4C] FIG. 4C shows additional details of the example microactuator having a rotary solenoid microactuator with a single drive coil shown in the example of FIGS. 4A and 4B. [Figure 4D] FIG. 4D shows additional details of the example microactuator having a rotary solenoid microactuator with a single drive coil shown in the example of FIGS. 4A and 4B. [Figure 5A] FIG. 5A shows another embodiment suitable for providing a rotary solenoid microactuator with multiple drive coils. [Figure 5B] FIG. 5B shows another embodiment suitable for providing a rotary solenoid microactuator with multiple drive coils. [Figure 5C] FIG. 5C shows another embodiment suitable for providing a rotary solenoid microactuator with multiple drive coils. [Figure 5D] FIG. 5D shows another embodiment suitable for providing a rotary solenoid microactuator with multiple drive coils. [Figure 6A] FIG. 6A shows an example of dual drive coils similar to the example of FIGS. 4A and 4B. [Figure 6B] FIG. 6B shows an example of dual drive coils similar to the example of FIGS. 4A and 4B. [Figure 6C] FIG. 6C shows an example of dual drive coils similar to the example of FIGS. 4A and 4B. [Figure 6D] FIG. 6D shows an example of dual drive coils similar to the example of FIGS. 4A and 4B. [Figure 7] FIG. 7 illustrates an example of a wearable drug delivery system that can incorporate the exemplary microactuators described herein. DETAILED DESCRIPTION OF THE INVENTION

[0015] The following description provides a detailed description of the microactuator. An example of the microactuator described herein may be a rotary solenoid microactuator having one or more drive coils.

[0016] In one embodiment, the microactuator 100 may have a single magnet 110 that provides a static N-S (N is red and S is green) magnetic field and two (or a pair) focusing elements 121 and 122. The two focusing elements 121 and 122 may be physically connected (e.g., directly) to the magnet and configured or operable to focus the magnetic field and align it with one or more drive coils 131, 132, e.g., a first drive coil and a second drive coil. In some examples, the magnet 110 and focusing elements 121, 122 are configured to rotate on a spindle 140. The spindle 140 may be operable to snap into a main structure 115 that is configured with the drive coils 131 and 132. For example, the drive coils 131, 132 may be held within the main structure 115 and provide a controllable magnetic field to attract or repel the static magnetic field of the magnet 110. In an embodiment, each drive coil 131 and 132 can be individually controlled to attract or repel the static magnetic field of magnet 110, causing rotation in either of two rotational directions.

[0017] The yoke 150 (or similar mechanism) is configured to transfer the torque / force of the actuator 100 to a pump mechanism (not shown in this example). More specifically, the yoke 150 may have one or more yoke extensions 153, 155 (or yoke arms). The yoke extensions may form yoke bearings. The yoke extensions 153, 155 may be coupled to or integral with either the first focusing element 121 or the second focusing element 122. Alternatively, the yoke extensions 153, 155 may be coupled to or integral with both the first focusing element 121 and the second focusing element 122. While the yoke 150 is shown U-shaped with the yoke extensions 153 and 155 forming a U-shaped extension, other shapes are also envisioned, such as the yoke extensions 153, 155 extending from the yoke 150 in a T- or Y-shape.

[0018] The process for assembling the actuator structure and sequence can be described with reference to FIG. 1B . The focusing elements 121 and 122 can sandwich the spindle 140 and magnet 110 to form a complete magnetic assembly 160. In some embodiments, the first focusing element has a first spindle opening, and the second focusing element has a second spindle opening, with the spindle configured to protrude through the first and second spindle openings and connect to the main structure. The first and second spindle openings can be centrally positioned within the first and second focusing elements. Square keying features 141 and 142 (also called keying features or interlocking features) located on either end of the spindle 140 ensure the alignment of the upper and lower focusing elements 121 and 122, respectively, to the spindle 140. A heat staking operation or the like can be used to lock the focusing elements 121, 122, and magnet 110 to the spindle 140. The complete magnetic assembly 160 may be an inseparable assembly once constructed.

[0019] Snap features 117 or the like on the top and bottom of the main structure 115 may be operable to snap the spindle 140 into place within the main structure 115 and provide axial and radial bearing-like features for the spindle 140. The snap features 117 may be resilient. Further, the snap features 117 may each comprise a bearing surface configured to contact a portion of the spindle 140. In particular, the snap features may each have a bearing surface having an arcuate shape. Thus, in some embodiments, the snap features are configured to receive the spindle and are operable to provide axial and radial bearing-like features for the spindle. The drive coils 131 and 132 may be press-fit into pockets 119 of the main structure 115 to receive and position the respective drive coils 131 and 132 in alignment with the focusing elements 121, 122. Pocket 119 can function to maintain alignment and spacing of respective drive coils 131 and 132 with or within a gap (as shown in a later example) between first focusing element 121 and second focusing element 122. In some embodiments, the drive coils are disposed within pocket 119. In some embodiments, first drive coil 131 and second drive coil 132 are positioned on either side of the force transfer assembly within the main structure.

[0020] Ferrite cores 133 and 134 may be positioned within each drive coil 131 and 132 to help ensure that magnetic field lines (not shown in this example) exit from and interact with the permanent magnet magnetic field lines in an optimized direction from the drive coils 131 and 132. The ferrite cores 133 and 134 within each drive coil 133 and 134 help refine the shape of the magnetic field to optimize the magnetic force between the magnet 110 and the drive coils 131 and 132.

[0021] 2A and 2B show side and example magnetic field lines in a fully assembled microactuator according to an embodiment of the disclosed subject matter.

[0022] The complete magnetic assembly 200 may have two focusing elements 221 and 222 that rotate with the spindle 240, with the magnet 210 disposed between the two focusing elements 221 and 222. The focusing element 221 may be a first focusing element, and the focusing element 222 may be a second focusing element. Each of the focusing elements 221 and 222 of FIG. 1 may have a magnetic field inducing element, e.g., an element comprising or consisting of a magnetic material such as iron. The magnetic field inducing element may be a separate element from the focusing element or may be integrally formed with the focusing element. The first focusing element may have an upper element and a lower element. 2A, reference numeral 221-1U denotes an upper magnetic field inducing element (first upper magnetic field inducing element) on a first side of the first focusing element 221, reference numeral 220-2U denotes another upper magnetic field inducing element (second upper magnetic field inducing element) on a second side of the first focusing element, reference numeral 222-1L denotes a lower focusing element (first lower magnetic field inducing element) on a first side of the second focusing element, and reference numeral 222-2L denotes a lower focusing element (second lower magnetic field inducing element) on a second side of the second focusing element.

[0023] As shown on the right side of FIG. 2A , the upper magnetic field induction element 221-2U and the lower magnetic field induction element 221-2L induce the magnetic field generated by the magnet 210 (indicated by line 231) across the gap 225. In some embodiments, the upper magnetic field induction element 221-2U and the lower magnetic field induction element 221-2L are configured to form a gap separating the upper magnetic field induction element 221-2U and the lower magnetic field induction element 221-2L. Similarly, as shown on the left side of FIG. 2A , the gap 226 is located on the opposite side of the magnet 210 from the gap 225. Additionally, the magnetic field generated by the magnet 210 traverses the gap 226 (indicated by magnetic field lines 232).

[0024] As shown in FIG. 2B, drive coil 230 is typically positioned in gap 225 substantially equidistant from upper focusing element 221-2U and lower focusing element 221-2L. Drive coil 230 may be held in place in a pocket in the main structure, as shown in FIGS. 1A and 1B. The pocket (as shown in the previous example) may function to maintain alignment and spacing of the drive coil with or within gap 225 between the first and second focusing elements. Although not shown in this example, a drive coil similar to drive coil 230 is located in gap 226.

[0025] 3A and 3B show top views of the microactuator to illustrate the theory of operation of the example microactuator shown in FIGS. 1A-2B.

[0026] In operation, the microactuator 300 can be coupled to a power source operable to energize the drive coils 331 and 332 to attract (or repel) poles of a magnet (not shown in this example). For example, a current can be applied to the drive coil 331, causing the drive coil 331 to generate a magnetic field (N in this case), which can interact with a magnet, which may be a permanent magnet, to emit a magnetic field N. The combination of the magnetic field N generated by the drive coil 331 and the magnetic field N emitted by the magnet generates a force that repels the focusing element 321 from the drive coil 331 in the direction indicated by arrow A. Additionally or alternatively, a current can be passed through the drive coil 332, causing the drive coil 332 to generate a magnetic field (S in this case), which can interact with a magnet (e.g., a permanent magnet) to emit a magnetic field N. The combination of the magnetic field S generated by the drive coil 332 and the magnetic field N emitted by the magnet generates a force that attracts the focusing element 322 toward the drive coil 332 in the direction indicated by arrow B.

[0027] In response to the generated forces repelling focusing element 321 from drive coil 331 and / or attracting focusing element 322 toward drive coil 332, yoke 350 translates or rotates about the spindle in the direction indicated by arrow C. Reversing the current through the drive coil changes the direction of translation / rotation of yoke 350.

[0028] Additional features can be added to the examples shown in Figures 1A-3B. For example, an external spring can be added to bistable position the actuator at the end of the stroke. Thus, only one direction of current needs to be applied, as the spring can rotate the yoke 350 back to its original position (i.e., the position before the current was applied). Similarly, detents can be added to the spindle to bistable position the actuator at the end of the stroke. Furthermore, both an external spring and a detent in the spindle can be added to further bistable position the actuator at the end of the stroke beyond the single use of either the external spring or the detent in the spindle.

[0029] In a control example, the drive coils may be energized simultaneously to provide the repulsive and attractive magnetic forces, or the drive coils may be energized in an alternating or sequential order (e.g., the attraction drive coil may be energized first and the repulsion drive coil may be energized second), which may improve electrical efficiency.

[0030] In a further example, when the drive coil is energized, energy may be stored within the drive coil over an extended period of time and harvested using a capacitive circuit or the like. In one example, the drive coil may be treated as an inductor that stores energy and only drains the stored energy after it stops receiving a current input. This stored energy may be used to shorten the period that the drive coil is energized or may be transferred to a capacitor or the like for later reuse.

[0031] 4A and 4B show top and side views of an example force transfer assembly with a single drive coil that is part of a single drive coil rotary solenoid microactuator.

[0032] A top view of the force transfer assembly 405 and single drive coil 430 is shown in FIG. 4A. This top view of the force transfer assembly 405 and single drive coil 430 shows the spindle 410, keying mechanism 415 (also called a keying structure or interlocking mechanism), top focusing element 421, and single drive coil 430 with ferrite core 445. The drive coil 430 can be energized via electrical connection 433. As shown in later examples, electrical connection 433 can be coupled to control circuitry. Also shown in FIG. 4A is the yoke 450 of the bottom focusing element, hidden from view below the top focusing element 421. The top focusing element 421 hides the magnet in FIG. 4A. The force transfer assembly and single drive coil 400 differs from previous examples in that it uses a single gap and drive coil instead of splitting the magnetic field focusing element between two drive coils.

[0033] 4B includes additional details, such as a magnet 425 positioned between the top and bottom focusing elements 421, 422. The side view also shows a ferrite core 445 extending through the single drive coil 430. In this example, the ferrite core 445 extends above the upper edge and below the lower edge of the single drive coil 430. The top focusing element 421 is configured similarly to focusing element 221, with an upper focusing element that curves downward toward the drive coil 430, and the bottom focusing element 422 is configured similarly to focusing element 222, with a lower focusing element that curves upward toward the drive coil 430.

[0034] Figures 4C and 4D show additional details of an example microactuator, including a rotary solenoid microactuator with a single drive coil as shown in the example of Figures 4A and 4B. Figures 4C and 4D show an example microactuator 400 having a force transfer assembly 405 and a main structure 465 for supporting a single drive coil 430. The drive coil 430 may be held in a pocket to ensure alignment of the drive coil 430 with the focusing elements 421 and 422.

[0035] In an example of operation of the microactuator 400 described with reference to FIG. 4C , the drive coil 430 can be energized with a magnetic polarity that repels the magnetic field generated by the magnet 425 and directed toward the drive coil 430 by the focusing elements 421 and 422. In response to energizing the drive coil 430, the force transmission assembly 405 can rotate in the direction indicated by arrow C. An example of a drive mechanism coupling 455 is shown in FIGS. 4C and 4D . The drive mechanism coupling 455, and in particular its coupling element, can contact the yoke. In particular, the drive mechanism coupling 455, and in particular its coupling element, can be disposed between the yoke extensions. The drive mechanism coupling 455 is actuated by the yoke 450 within the focusing element 422 and responds to the rotation of the force transmission assembly 405 (in the direction of arrow C) by moving in the direction indicated by arrow CC. Movement of the drive mechanism coupling 455 in the direction indicated by arrow CC can cause the pump to initiate the transfer of a liquid medicament, for example, from a reservoir using reciprocating motion of the drive mechanism. In some embodiments, the yoke 450 actuates the drive mechanism to expel a first amount of liquid medication from the wearable medication delivery device. In some embodiments, movement of the yoke 550 in a first direction actuates the drive mechanism to expel a first amount of liquid medication from the wearable medication delivery device, and movement of the yoke in a second direction actuates the drive mechanism to expel a second amount of liquid medication from the wearable medication delivery device. Rotation of the force transfer assembly 405 in the direction of arrow CC can be stopped in various ways, such as by de-energizing the drive coil 430, by energizing the drive coil 430 to generate an opposite magnetic polarity (i.e., the magnetic field attracts the focusing elements 421 and 422), by a mechanical stop, etc. As shown in FIG. 4D , the drive coil 430 can be energized to have a magnetic polarity that attracts the magnetic field generated by the magnet 425 and directed toward the drive coil 430 by the focusing elements 421 and 422. In response to energizing drive coil 430, force transfer assembly 405 may rotate in the direction indicated by arrow D. Drive mechanism linkage 455 is actuated by yoke 450 within focusing element 422 and responds to the rotation of force transfer assembly 405 (in the direction of arrow D) by moving in the direction indicated by arrow DD.Movement of drive mechanism coupling 455 in the direction indicated by arrow DD may cause the pump to enter another stage (or stages) of transfer of a drug solution or the like from a reservoir.

[0036] Microactuator 400 may also have a biasing spring (not shown in this example) to ensure that yoke 450 returns to a starting position after each actuation of yoke 450. The biasing spring may allow for only one direction of current to be applied to drive coil 430, such that the magnetic field moves the yoke in one direction and the biasing spring moves the yoke in the opposite direction.

[0037] 5A-5D illustrate another embodiment suitable for providing a quadruple drive coil rotary solenoid microactuator. FIG. 5A shows a schematic diagram of a force transfer assembly 540 configured to operate with four drive coils 511, 513, 515, and 517. For example, the oblong drive coils in the previous example, such as reference numerals 131 and 132 in FIG. 1A, can be split into two oppositely wound coils 511 / 513 and 515 / 517 on each side of the force transfer assembly 540. The two oppositely wound coils 511 / 513 can be referred to as a first pair of drive coils, and the two oppositely wound coils 515 / 517 can be referred to as a second pair of drive coils. The two oppositely wound drive coils 511 / 513 and 515 / 517 on each side can provide additional initial drive force (compared to the single drive coils 131 and 132 in FIG. 1A) and aid in positioning the yoke 550. The force transfer assembly 540 and the four drive coils 511, 513, 515, and 517 can be coupled to a control circuit and drive mechanism of a wearable drug delivery system (both shown in later examples). In some embodiments, the main structure further comprises a pocket for receiving and holding each drive coil of the first pair of drive coils and each drive coil of the second pair of drive coils, the pockets configured to provide a gap between the first and second focusing elements to maintain alignment of each drive coil of the first pair of drive coils with each drive coil of the second pair. In some embodiments, the main structure further comprises a plurality of pockets, each pocket having a respective drive coil of the first pair of drive coils and a respective drive coil of the second pair of drive coils, the pockets configured to provide a gap between the first and second focusing elements to maintain alignment of each drive coil of the first pair of drive coils with each drive coil of the second pair.

[0038] 5B provides a schematic diagram showing the positioning of focusing elements 521 and 522 relative to energized drive coil 511 to attract focusing elements 521 and 522. The two oppositely wound drive coils on each side of force transfer assembly 540 (e.g., reference numbers 511 and 513, 515 and 517) may be wound from the same wire (a first coil wound in a first direction and a second coil wound in a second direction opposite the first direction of wire wound around the first coil), such as electrical connection 533 and electrical connection 534, to simplify the manufacturing process. In the example of operation described with reference to both Figures 5A and 5B, control circuitry (shown in another example) energizes drive coils 513 and 515 to cause drive coils 511 and 517 to have a magnetic polarity that attracts focusing elements 521 and 522, while drive coils 513 and 515 are energized with a magnetic polarity that repels focusing elements 521 and 522. Magnet 510 supplements the attractive force generated by each drive coil 511 and 517 and the repulsive force generated by each drive coil 513 and 515. In this first state, yoke 550 moves in the direction of arrow AA. Figures 5A and 5B show the state after yoke 550 has moved in the direction of arrow AA. Yoke 550 may interact with a drive mechanism to expel a first quantity of liquid medicament from the wearable medication delivery device.

[0039] Conversely, as shown in Figures 5C and 5D, control circuitry (shown in another example) can energize drive coils 513 and 515, causing drive coils 515 and 513 to generate magnetic polarities that attract focusing elements 521 and 522, while energizing drive coils 511 and 517, causing drive coils 513 and 515 to generate magnetic polarities that repel focusing elements 521 and 522. Magnet 510 supplements the attractive forces generated by respective drive coils 513 and 515 and the repulsive forces generated by respective drive coils 511 and 517. Figures 5C and 5D show the state after yoke 550 has moved in the direction of arrow BB. Movement of yoke 550 in the direction of arrow BB can also cause the drive mechanism of the wearable medication delivery device to expel a second amount of liquid medication from the reservoir of the wearable medication delivery device. In some embodiments, the microactuator further comprises a spindle, wherein the magnet has an opening through which the spindle passes, the first focusing element has a first spindle opening, and the second focusing element has a second spindle opening, the spindle configured to protrude through the first spindle opening and the second spindle opening, in particular the spindle having at least one, in particular two, key structures configured to interlock with the first spindle opening and / or the second spindle opening.

[0040] 6A-6D show an example of dual drive coils similar to the example of FIGS. 4A and 4B.

[0041] As shown in FIG. 6A (right side), a pair of oppositely wound drive coils 611 and 613 on one side of the force transmission assembly 640 can provide the directional control and positioning of the yoke 660 required when the output torque generated by the drive coils 611 and 613 and the magnet 610 (shown in FIG. 6B) is sufficient to drive the drive mechanism of the wearable medication delivery device.

[0042] The two oppositely wound drive coils 611 and 613 can provide additional initial drive force and aid in positioning the yoke 660. The force transfer assembly 640 and the two drive coils 611 and 613 can be coupled to the control circuitry and drive mechanism of the wearable drug delivery system. The two oppositely wound drive coils (e.g., reference numerals 611 and 613) of the force transfer assembly 640 can be wound from the same wire (the first coil wound in a first direction and the second coil wound in a second direction opposite the first direction) to simplify the manufacturing process. Figure 6B provides a schematic diagram showing the positioning of the focusing elements 621 and 622 relative to the energized drive coil 613 to attract the focusing elements 621 and 622 and the magnet 610. In the example of operation described with reference to both Figures 6A and 6B, control circuitry (shown in another example) can energize drive coil 613 to attract focusing elements 621 and 622, while energizing drive coil 611 to repel focusing elements 621 and 622. Magnet 610 can supplement the attractive force generated by drive coil 613 and the repulsive force generated by each drive coil 611. In this first state, yoke 660 moves in the direction of arrow AAA. Figures 6A and 6B show the yoke 660 after it has moved in the direction of arrow AAA. Yoke 660 can interact with a drive mechanism to expel a first quantity of liquid medicament from the wearable medication delivery device.

[0043] Conversely, as shown in Figures 6C and 6D, control circuitry (shown in another example) can energize drive coil 611, causing drive coil 611 to attract focusing elements 621 and 622, while energizing drive coil 613, causing focusing elements 621 and 622 to repel. Magnet 610 can supplement the attractive force generated by drive coil 611 and the repulsive force generated by each drive coil 613. In this second state, yoke 660 moves in the direction of arrow BBB. Figures 6C and 6D show the state after yoke 660 has moved in the direction of arrow BBB. Movement of yoke 660 in the direction of arrow BBB also causes the drive mechanism to expel a second amount of liquid medication from the wearable medication delivery device.

[0044] The force transfer assembly 640 and drive coils 611 and 613 may be held in a structure similar to the main structure 115 of Figures 1A and 1B. The microactuators described herein can be used in conjunction with computer control, for example, drug delivery algorithms.

[0045] Types of drug delivery algorithms (MDAs) may include "artificial pancreas" algorithm-based systems or, more generally, artificial pancreas (AP) applications. For ease of description, computer programs and computer applications that implement drug delivery algorithms or applications may be referred to herein as "AP applications," which may be configured to provide automated delivery of insulin based on analyte sensor inputs, such as signals received from analyte sensors, such as continuous blood glucose monitors, ketone sensors, etc. The signals from the analyte sensors may include blood glucose readings, timestamps, etc.

[0046] Additionally or alternatively, while the disclosed examples have been described with reference to closed-loop algorithm implementations, variations of the disclosed examples may be implemented to enable open-loop use. Open-loop implementations allow for the use of different modalities of insulin delivery, such as smart pens, syringes, etc. For example, the disclosed AP application and algorithms may be operable to perform various functions associated with open-loop operation, such as generating prompts requesting input of information such as diabetes type, weight, or age. Similarly, insulin doses may be received by the AP application or algorithm from the user via a user interface. Other open-loop operations may also be performed by adjusting user settings, etc., in the AP application or algorithm.

[0047] FIG. 7 illustrates an example of a wearable drug delivery system that can incorporate the exemplary microactuators described herein.

[0048] The wearable drug delivery system 700 may include a control circuit 710, a power source 720, a micro actuator 730, a drive mechanism 740, and a reservoir 750. The wearable drug delivery device 700 may be a wearable device worn on the user's body. The wearable drug delivery device 700 may be directly connected to the user (for example, it may be directly attached to the user's body part and / or skin via an adhesive or the like). In one embodiment, the surface of the wearable drug delivery device 700 may have an adhesive for facilitating attachment to the user's skin.

[0049] The micro actuator 730 may be similar to the micro actuator having the force transmission assembly and drive coil configuration shown in the previous examples of FIGS. 1A-6D. The reservoir 750 can store a liquid drug. Examples of liquid drugs include, for example, insulin, glucagon-like peptide-1 (GLP-1), pramlintide, glucagon, GLP-1, pramlintide, and co-formulations of two or more of insulin; and any liquid drug that can be administered by a drug delivery device via a subcutaneous cannula, including opioid or narcotic drugs (such as morphine, etc.), methadone, arthritis drugs, hormones such as estrogen and testosterone, blood pressure drugs, chemotherapy drugs, pain relievers such as reproductive ability drugs, or may include them.

[0050] The micro actuator 730 can be physically connected to the drive mechanism 740 via a connecting portion 733. The connecting portion 733 can be a mechanical structure separate from the drive mechanism 740 that connects the yoke (shown in other examples) of the micro actuator 730 to the drive mechanism 740, or can be a mechanical structure that is an integral part of the drive mechanism 740. The connecting portion 733 can extend the movement of the yoke of the micro actuator to the drive mechanism, or can convert the movement of the yoke into movement in a different plane, or convert linear movement into rotational movement, etc. Alternatively, the connecting portion 733 may be omitted, and the yoke of the micro actuator 730 can be directly connected to the drive mechanism 740.

[0051] The drive mechanism 740 may include several mechanical elements, such as gears, gear trains, etc., that convert the linear motion of the yoke into another form of motion, such as rotational motion of the yoke. The drive mechanism 740 may also include an elongated shaft that couples to the first interface (i.e., plunger) of the reservoir 750 or to another interface.

[0052] Drive coupling 743 can couple drive mechanism 740 to reservoir 750. Drive coupling 743 can have structural elements that allow a quantity of liquid medication stored in reservoir 750 to be expelled from reservoir 750 via fluid pathway 760.

[0053] Power source 720 may be a power source such as a battery, a supercapacitor, an energy harvesting circuit, etc. Power source 720 may be configured to last for hours, days, etc. Power source 720 may be replaceable and / or rechargeable via a wired or wireless connection.

[0054] The wearable medication delivery device 700 may include a control circuit 710, which may be implemented in hardware, software, or any combination thereof. The control circuit 710 may be, for example, a microprocessor, logic circuitry, a field programmable gate array (FPGA), an application specific integrated circuit (ASIC), or a microprocessor coupled to a memory device. The control circuit 710 may be operable to perform several functions, such as executing a control application stored in a memory device (not shown). In this example, the control circuit 710 is operable to execute logic that causes a control signal in the form of a voltage or current to be applied to the microactuator 730 via one or more drive coils (shown in the previous example), as described with reference to the examples of FIGS. 1A-6D.

[0055] Specific embodiments of the present disclosure have been described above. However, it should be expressly noted that the present disclosure is not limited to those embodiments; rather, additions and modifications to those explicitly described herein are also intended to be within the technical scope of the disclosed embodiments. Furthermore, it should be understood that the features of the various embodiments described herein are not mutually exclusive and may exist in various combinations and permutations, even if such combinations or permutations are not expressly set forth herein, without departing from the spirit and scope of the disclosed embodiments. Indeed, variations, modifications, and other implementations of what is described herein will occur to those skilled in the art without departing from the spirit and scope of the disclosed embodiments. Therefore, the disclosed embodiments should not be defined solely by the foregoing illustrative description.

[0056] It is emphasized that the Summary of the Disclosure is provided to allow the reader to quickly ascertain the nature of the technical disclosure. It is understood that the Summary is not used to interpret or limit the scope of the claims. Moreover, in the foregoing Detailed Description, various features are grouped together in a single example to streamline the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed examples require more features than are expressly recited in each claim. Rather, as the following claims reflect, novel subject matter lies in fewer than all features of a single disclosed embodiment. Accordingly, the following claims are hereby incorporated into the Detailed Description, with each claim standing on its own as a separate example. In the appended claims, the terms "including" and "in which" are used as the plain-English equivalents of the respective terms "comprising" and "where." Furthermore, the terms "first," "second," "third," etc. are used merely as labels and are not intended to impose numerical requirements on their objects.

[0057] The foregoing description of embodiments has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure to the precise form disclosed. Many modifications and variations are possible in light of this disclosure. The scope of the disclosure is not limited by this detailed description, but rather by the scope of the claims appended hereto. Future applications claiming priority to this application may claim the disclosed subject matter differently and may generally comprise any set of one or more features as variously disclosed or otherwise demonstrated herein.

[0058] While the present invention is defined in the appended claims, it should be understood that the invention may also be defined according to the following embodiments. A microactuator for a wearable medication delivery device, The microactuator comprises: a force transfer assembly having a first focusing element and a second focusing element, the second focusing element having a yoke; a drive coil operable to attract or repel the first focusing element and the second focusing element; a main structure configured to hold the force transfer assembly and the drive coil in alignment with one another. The microactuator comprises: 10. The microactuator of claim 1, further comprising a spindle, wherein the first focusing element has a first spindle opening and the second focusing element has a second spindle opening, the spindle protruding through the first spindle opening and the second spindle opening and configured to couple to the main structure. The microactuator comprises: The microactuator of claim 1 , further comprising a magnet disposed between the first focusing element and the second focusing element. The main structure is The microactuator of claim 1 , further comprising a snap mechanism configured to receive the spindle and operable to provide an axial and radial bearing-like mechanism for the spindle. The main structure is The microactuator of claim 1 , further comprising a pocket that receives and holds the drive coil. The main structure is The microactuator of claim 1 , further comprising a pocket further operable to maintain alignment of the drive coil within a gap between the first focusing element and the second focusing element. The drive coil The microactuator of claim 1 , further comprising first and second drive coils positioned on opposite sides of the force transfer assembly within the main structure. The first focusing element comprises: The microactuator of claim 1 , further comprising a first upper magnetic induction element and a second upper magnetic induction element disposed across each other on either side of the first focusing element. The first focusing element comprises: an upper magnetic field inducing element disposed on one side of the first focusing element; The second focusing element comprises: a lower magnetic induction element disposed on a lower side of the lower magnetic field induction element of the second focusing element; The microactuator of claim 1 , wherein the upper magnetic inductive element and the lower magnetic inductive element are configured to form a gap separating the upper magnetic inductive element from the lower magnetic inductive element. The microactuator of claim 1 , wherein the yoke comprises a yoke extension operable to interact with a drive mechanism of a wearable medication delivery device. 10. The microactuator of claim 1, wherein the yoke comprises a yoke extension extending from either the first focusing element or the second focusing element, the yoke extension causing the yoke to be T-shaped, U-shaped, or Y-shaped. A microactuator for a wearable medication delivery device, The microactuator comprises: a force transfer assembly having a magnet between the first focusing element and the second focusing element, the second focusing element having a yoke; a first pair of drive coils; a second pair of drive coils; each drive coil of the first pair of drive coils is energized with an opposite magnetic polarity to the other drive coil to attract or repel the first focusing element and the second focusing element in a first direction; a microactuator, wherein each drive coil of the second pair of drive coils is energized with an opposite magnetic polarity to the other drive coil to attract or repel the first focusing element and the second focusing element in a second direction opposite the first direction. The microactuator comprises: 13. The microactuator of claim 12, comprising a main structure configured to align the force transfer assembly and each drive coil of the first pair of drive coils and each drive coil of the second pair of drive coils to enable rotation of the force transfer element. 14. The microactuator of claim 13, wherein the main structure comprises a snap mechanism configured to receive the spindle and operable to provide an axial and radial bearing-like mechanism for the spindle. The main structure is 14. The microactuator of claim 13, further comprising: pockets configured to receive and hold each drive coil of the first pair of drive coils and each drive coil of the second pair of drive coils, respectively, the pockets configured to maintain alignment of each drive coil of the first pair of drive coils with each drive coil of the second pair of drive coils such that there is a gap between the first focusing element and the second focusing element. each drive coil of the first pair of drive coils being wound from the same piece of wire; 13. The microactuator of claim 12, wherein the wire is wound in a first direction for a first respective drive coil of the first pair of drive coils and in a second opposite direction for a second respective drive coil of the first pair of drive coils. The microactuator of claim 12 , wherein the yoke comprises a yoke extension operable to interact with a drive mechanism of a wearable medication delivery device. 13. The microactuator of claim 12, wherein the yoke comprises a yoke extension extending from either the first focusing element or the second focusing element, and the yoke is T-shaped, U-shaped, or Y-shaped. the microactuator further comprises a spindle; 13. The microactuator of claim 12, wherein the magnet has an opening through which the spindle passes, the first focusing element has a first spindle opening, the second focusing element has a second spindle opening, and the spindle is configured to protrude through the first spindle opening and the second spindle opening. 20. The microactuator of claim 19, wherein the spindle has a key structure configured to interlock with the first spindle opening and / or the second spindle opening.

Claims

1. A microactuator for a wearable medication delivery device, The microactuator comprises: a force transfer assembly having a first focusing element and a second focusing element, the second focusing element having a yoke; a drive coil operable to attract or repel the first focusing element and the second focusing element; a main structure configured to hold the force transfer assembly and the drive coil in alignment with one another.

2. The microactuator comprises:

10. The microactuator of claim 1, further comprising a spindle, wherein the first focusing element has a first spindle opening and the second focusing element has a second spindle opening, the spindle protruding through the first spindle opening and the second spindle opening and configured to couple to the main structure.

3. The microactuator comprises: The microactuator of claim 1 , further comprising a magnet disposed between the first focusing element and the second focusing element.

4. The main structure is The microactuator of claim 1 , further comprising a snap mechanism configured to receive a spindle and operable to provide an axial and radial bearing-like mechanism for the spindle.

5. The main structure is 10. The microactuator of claim 1, further comprising a pocket that receives and holds the drive coil, more particularly, the pocket further operable to maintain alignment of the drive coil within a gap between the first focusing element and the second focusing element.

6. The drive coil The microactuator of claim 1 , further comprising first and second drive coils positioned on opposite sides of the force transfer assembly within the main structure.

7. The first focusing element comprises: The microactuator of claim 1 , wherein a first upper magnetic induction element and a second upper magnetic induction element are disposed across each other on either side of the first focusing element.

8. The first focusing element comprises: an upper magnetic field inducing element disposed on one side of the first focusing element; The second focusing element comprises: a lower magnetic field inducing element disposed on a lower side of the second focusing element than the upper magnetic field inducing element; The microactuator of claim 1 , wherein the upper magnetic field inducing element and the lower magnetic field inducing element are configured to form a gap separating the upper magnetic field inducing element from the lower magnetic field inducing element.

9. the yoke comprising a yoke extension operable to interact with a drive mechanism of the wearable medication delivery device; More specifically, the microactuator of claim 1 , wherein the yoke comprises a yoke extension extending from either the first focusing element or the second focusing element, the yoke extension causing the yoke to be T-shaped, U-shaped, or Y-shaped.

10. A microactuator for a wearable medication delivery device, The microactuator comprises: a force transfer assembly having a magnet between a first focusing element and a second focusing element, the second focusing element having a yoke; a first pair of drive coils; a second pair of drive coils; each drive coil of the first pair of drive coils is energized with an opposite magnetic polarity to the other drive coil to attract or repel the first focusing element and the second focusing element in a first direction; wherein each drive coil of the second pair of drive coils is energized with an opposite magnetic polarity to the other drive coil to attract or repel the first focusing element and the second focusing element in a second direction opposite the first direction.

11. The microactuator comprises:

11. The microactuator of claim 10, comprising a main structure configured to align the force transfer assembly and each drive coil of the first pair of drive coils and each drive coil of the second pair of drive coils to enable rotation of a force transfer element, more particularly, the main structure comprising a snap mechanism configured to receive a spindle and operable to provide an axial and radial bearing-like mechanism for the spindle.

12. The main structure is 12. The microactuator of claim 11, further comprising: pockets that receive and hold each drive coil of the first pair of drive coils and each drive coil of the second pair of drive coils, respectively, the pockets configured to maintain alignment of each drive coil of the first pair of drive coils with each drive coil of the second pair of drive coils such that there is a gap between the first focusing element and the second focusing element.

13. each drive coil of the first pair of drive coils being wound from the same piece of wire; 11. The microactuator of claim 10, wherein the wire is wound in a first direction for a first respective drive coil of the first pair of drive coils and in a second opposite direction for a second respective drive coil of the first pair of drive coils.

14. The microactuator of claim 10, wherein the yoke comprises a yoke extension operable to interact with a drive mechanism of a wearable medication delivery device, more specifically, the yoke comprises a yoke extension extending from either the first focusing element or the second focusing element, the yoke extension causing the yoke to be T-shaped, U-shaped, or Y-shaped.

15. the microactuator further comprises a spindle; 11. The microactuator of claim 10, wherein the magnet has an opening through which the spindle passes, the first focusing element has a first spindle opening, and the second focusing element has a second spindle opening, the spindle is configured to protrude through the first spindle opening and the second spindle opening, and in particular the spindle has at least one, in particular two, key structures configured to interlock with the first spindle opening and / or the second spindle opening.

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