A method of operating a breast pump device

Abstract

The present invention relates to a method of operating a breast pump device (100) comprising a controller (126), a motor (6) and a movable pump actuator, wherein the pump actuator is driven by the motor (6) to generate a vacuum that is applied to a breast of a lactating user via a breast shield (122) and the motor (6) is controlled by the controller (126), and wherein the controller (126) uses a predetermined trajectory of the pump actuator to control the motor (6). The present invention aims to provide a breast pump and a method of operating the same, which can reproduce clinically tested vacuum curves as best as possible and avoid or at least reduce at least one of noise, electrical stress and mechanical stress.

Description

[0001] MAG 11 / 24 1

[0002] A method of operating a breast pump device

[0003] The present invention relates to a method of operating a breast pump device and a breast pump device with a controller to execute said method.

[0004] Breast pumps for use by nursing mothers are well known. They allow the nursing mothers to express the breastmilk as necessary or convenient, and further provide collection of the breastmilk for later use. For some mothers, breast pumps may be a necessity, such as when the child has suckling problems, or if the mother has problems with excessive or deficient milk production, or soreness, deformation, or injury of the mammilla.

[0005] Electrically-driven breast pumps are commonplace, typically including a vacuum pump which has an electric motor that plugs into standard house current, and / or operates with battery power. Advantages of this type of pump are convenience, ready controllability and regulation of the vacuum, and in many instances the ability to pump both breasts at once.

[0006] Electrically-driven, motorized breast pumps generally have a driving mechanism for cyclically generating the vacuum (negative pressure) to be applied at the breast geared to a particular sequence, or curve, of vacuum or negative pressure increase (i.e. increasing suction), and then release. The cycling vacuum reproduces baby behavior and has at least a stimulation pattern and an expression pattern; examples of such patterns are reproduced in WO 2021 160875, WO 2010 096 547 and WO 03082 378. Each pattern is made of vacuum curves that are cyclically reproduced by the vacuum pump.

[0007] Breast pumps may implement vacuum curves that reproduce as best as possible clinically tested curves. Some breast pumps have an electric motor that drives a movable pump actuator, such as a piston, which generates the vacuum to be applied at the breast via a breast shield. Reproduction of the clinically tested curves can involve trajectories of the movable pump actuator (position Vs time) that cause high velocities and high accelerations. High accelerations, however, stress the mechanical components. It is desirable that such a stress is kept within acceptable limits. In addition, high accelerations can make the movable pump actuator to generate knocking sounds. Such sounds are often experienced as very annoying during use of the breast pumps, not only for the moms, but also (and in particular) for the babies, in case they are with the mom.

[0008] The present invention aims to provide a breast pump and a method of operating the same, which can reproduce the clinically tested curves as best as possible and avoid or at least reduce at least one of noise, electrical stress and mechanical stress.

[0009] To cope with this problem, the present invention provides a breast pump device with a controller, a motor, a movable pump actuator and a breast shield, wherein the controller is configured to execute a method of operating the breast pump device described in the following. Typically, the breast pump device also includes a milk container providing a reservoir for the expressedMAG 11 / 24 2

[0010] milk. In the method of operating the breast pump device according to the present invention, the pump actuator is driven by the motor to generate a vacuum that is applied to a breast of a lactating user via a breast shield and the motor is controlled by the controller, wherein the controller uses a predetermined trajectory of the pump actuator to control the motor. Essentially, a trajectory is a curve representing the position of the movable pump actuator overtime. The movable pump actuator can be a piston.

[0011] In general, the predetermined trajectory causes predefined velocities and accelerations of the movable pump actuator. Thereby, the acceleration of the movable pump actuator can be controlled. Preferably, the acceleration of the pump actuator is restricted to not exceed a predetermined threshold value. Said predetermined threshold value can be 2 m / s2, 2.5 m / s2or3 m / s2.

[0012] According to a preferred embodiment of the method, the controller generates a control signal to control the motor based on at least one of an expected position of the pump actuator according to the trajectory, a measured position of the pump actuator, an expected velocity of the pump actuator derived from the expected position of the pump actuator, a measured velocity of the pump actuator, an expected acceleration of the pump actuator derived from the expected position of the pump actuator, and a measured magnitude of the vacuum. In general, the velocity is the first derivative of the position and the acceleration is the second derivative of the position. Thus, when an expected position of the pump actuator corresponds to a position determined by the trajectory, the expected velocity corresponds to the first derivate and the acceleration corresponds to the second derivate. The magnitude of the vacuum can be obtained by a direct measurement with a vacuum sensor. Also, the position and the velocity of the pump actuator can be, in principle, measured directly using suitable sensors for detecting a position and a velocity of the pump actuator.

[0013] The controller may comprise a feedback control part including a PI control unit calculating an error value based on a difference between the expected position of the pump actuator according to the trajectory and the measured position of the pump actuator, wherein the expected position of the pump actuator according to the trajectory corresponds a desired target value. Additionally, the controller may comprise a D control unit calculating another error value based on a difference between the expected velocity of the pump actuator and the measured velocity of the pump actuator. Thus, the controller may essentially be configured as a PI D controller or at least comprise a PID controller.

[0014] According to a further preferred embodiment of the method, the controller comprises a position control module associated with the position of the pump actuator and a current control module associated with the current to drive the motor based on a current set point signal generated by and received from the position control module, wherein the position control module includes the feedback control part, a feedforward control part, and a summing circuit, the feedback controlMAG 11 / 24 3

[0015] part compares the expected position and the expected velocity of the pump actuator with the measured position and the measured velocity of the pump actuator, calculates a first error signal corresponding to a difference between the expected position and the measured position and a second error signal corresponding to a difference between the expected velocity and the measured velocity, multiplies the first error signal by a first factor and the second error signal by a second factor, and feeds the multiplied error signals to the summing circuit, the feedforward control part receives the expected acceleration of the pump actuator, the expected velocity and the measured magnitude of the vacuum, multiplies the expected acceleration of the pump actuator by a third factor and feeds it to the summing circuit, multiplies the expected velocity of the pump actuator by a fourth factor and feeds it to the summing circuit and multiplies the measured magnitude of the vacuum by a fifth factor and feeds it to the summing circuit, the summing circuit sums all values fed into it and generates the current set point signal. The current set point signal can be fed to the current control module, which can generate based on the given set point a motor drive signal. The motor drive signal is fed to the motor to drive it. Generating the motor drive signal for the motor based on a given set point can be commonplace.

[0016] According to a preferred embodiment of the method, the measured position and the measured velocity of the pump actuator are determined by measuring a position and a velocity of the motor and estimating a corresponding position and corresponding velocity of the pump actuator. That is, it is preferable to measure the position and the velocity of the pump actuator indirectly. For measuring the position and the velocity of the motor, at least one hall sensor can be used. A brushless motor is typically provided with three hall sensors.

[0017] According to a preferred embodiment of the method, the user selects a program comprised of at least one vacuum curve, preferably one clinically tested vacuum curve, from at least one set of vacuum curves, preferably a set of clinically tested vacuum curves, each vacuum curve corresponding to a different trajectory of the pump actuator being stored in the breast pump device as discontinuous data points, wherein the controller calculates the curve between the data points by interpolation and generates the corresponding trajectory of the pump actuator. A set of clinically tested vacuum curves may be comprised of at least 10 curves and preferably between 15 to 25 curves. More than one set may be provided, each set preferably comprising between 15 to 25 curves and each set having a different shape or profile, wherein the different curves of one set correspond to different vacuum levels. The generated trajectory may be sampled in order to save memory. Further, a sampled trajectory can facilitate its reproduction by the movable pump actuator. The sample rate can be, for example, 10 kHz. The stored discontinuous data points may indicate the local minima and / or maxima of the trajectory. Further, the stored data points can be chosen as the positions of the pump actuator corresponding to the transitions of the differentMAG 11 / 24 4

[0018] vacuum curve phases. Such phases are: vacuum rise, vacuum peak, vacuum dip, vacuum hold, vacuum release and vacuum relaxation.

[0019] According to a further preferred embodiment of the method, the curve between two adjacent discontinuous data points that have a different position value is calculated by a sinusoidal interpolation. The curve between two adjacent discontinuous data points that have the same position value may be simply a straight line. Preferably, the generated trajectory is a smooth curve.

[0020] According to a preferred embodiment of the method, a variation of acceleration peaks of the pump actuator resulting from any trajectory is within a predetermined range. Said predetermined range may correspond to a variation of a factor of three. Keeping the variation of acceleration peaks resulting from an individual trajectory within the predetermined range may contribute to create a homogenous sound which can be experienced as less annoying.

[0021] According to a preferred embodiment of the method, the controller is configured to adjust the brightness of a display of the breast pump device to different surrounding settings, preferably based on a signal received from an ambient light sensor. That is, the controller may be configured to dim the display of the breast pump device when a dark environment is detected.

[0022] According to a preferred embodiment of the method, the controller is adapted to work with a voltage input of between 9V to 24V and more preferably between 10V to 20V. Power supply for said voltage input may be provided, for example, by at least one battery. Alternatively, power may be provided to the breast pump device through standard current via a power cord or some other appropriate power supply. An AC current from an AC power source may be converted via standard technology to DC current.

[0023] According to a preferred embodiment of the method, upon selection of a specific program by the user and at the start of cyclically generating the vacuum by cyclically repeating at least one trajectory, the breast pump device is ventilated. This may contribute to a calibration of the breast pump device. Preferably, the calibration by ventilation is performed only once at the beginning of a program when the pump starts to work; i.e. it is preferred that the calibration by ventilation is not performed in-between the cycles or during a program. For the calibration, the pump actuator may be controlled to move to a position in which it activates a ventilation valve, said position typically being located outside the positions reached throughout the trajectories.

[0024] According to a preferred embodiment, a breast pump device according to the present invention comprises a brushless motor. The advantage of brushless motors over brushed motors is the much longer lifetime, that makes the brushless motor particularly advantageous for professional pumps, for example pumps used in hospitals. Further, brushless motors may reproduce the clinically tested curves better than brushed motors.

[0025] According to a preferred embodiment, a breast pump device according to the present invention comprises a battery as power supply for the motor.MAG 11 / 24 5

[0026] These and other advantages of the invention will be further understood upon consideration of the following detailed description of certain embodiments, taken in conjunction with the drawings, in which:

[0027] Figure 1 is an illustration of a breast pump device for use in accordance with one embodiment of the present invention; and

[0028] Figure 2 is a schematic drawing of control modules for use in accordance with one embodiment of the present invention.

[0029] Figure 1 is an illustration of a breast pump device in accordance with one embodiment of the present invention. That breast pump device is generally described in U.S. Patent No. 6,547,756 or EP 2 878 317 B1, reference thereto can be made for salient details of this breast pump device.

[0030] As shown in Figure 1, the breast pump device 100 includes a breast pump 110, one or a plurality of the breast shield and container assemblies 120, which may provide a program card 130. Power may be provided to the breast pump apparatus 110 either through standard current via a power cord, a battery, or some other appropriate power supply.

[0031] The breast pump 110 may be either a double or a single pump. The single pump extracts milk from one breast at a time, and the double pump can be used to extract milk from both breasts at the same time. The breast pump 110 is attached to each of the plurality of the breast shield and container assemblies 120 with a tube 140. Each of the plurality of the breast shield and container assemblies 120 comprises a breast shield 122 and a container 124. The container 124 is used as a reservoir to store the pumped milk.

[0032] One significant aspect of the present invention is the ability to operate a movable pump actuator (not shown) of the breast pump 110 with different trajectories, each trajectory corresponding to a different vacuum curve.

[0033] The breast pump 110 utilizes a controller 126 for controlling an electric motor (not shown) that drives the movable pump actuator, so that the pump actuator generates a cyclic suction profile by cyclically reproducing at least one trajectory corresponding to a clinically tested vacuum curve. The controller has access (e.g. via a memory) to vacuum curves that are indicative of vacuum over time to be generated by the pump actuator and / or corresponding trajectories that are used by the controller to control the motor. The different trajectories of the pump actuator may be stored as discontinuous data points. A user of the breast pump device 100 may select a program comprised of at least one vacuum curve from at least one set of clinically tested vacuumMAG 11 / 24 6

[0034] curves and upon said selection, the controller may calculate the curve between the discontinuous data points by interpolation to generate the corresponding trajectories of the selected program.

[0035] The controller 126 or microprocessor-based system may be provided with user input, for example through the program card 130.

[0036] To extract breastmilk from a mother, the breast shields 122 are placed and centered over a mother's nipples. The breast pump apparatus 110 may be turned on by a user pressing a first button 112, and in an embodiment, the program card 130 is used with the device. The device reads the programs contained on the program card 130. The breast pump 110 may display instructions to the user via interface 150. The instructions may ask the user to select a particular program. Further, the user may select a vacuum level via a turnable button. The different vacuum curves of one set preferably correspond to different vacuum levels. The first button 112 may be configured as the turnable button for selecting a vacuum level. A second button 114 may be configured as a second turnable button for selecting a program and pressing the second button 114 may start the program. The interface 150 may then show instructions and / or graphics that let the user know that the program is starting. The discontinuous data points of the trajectories can be stored on a memory, which may be provided with the program card 150. In another embodiment, the discontinuous data points of the trajectories and / or the vacuum curves may be stored in the breast pump 110 and the program card 130 can be omitted. In such an embodiment, the user is asked to select a particular program directly upon turning on the device.

[0037] Figure 2 schematically illustrates control modules for use by a controller, for example by controller 126, in accordance with one embodiment of the present invention. As shown in figure 2, the controller comprises a position control module 2 associated with the position of the pump actuator and a current control module 4 associated with the current to drive the motor 6 (schematically illustrated as a circle) based on a current set point signal 8 generated by and received from the position control module 2. The current set point signal 8 is fed to the current control module 4, which generates a motor drive signal 10 based on the current set point signal 8. The motor drive signal 10 is fed to the motor 6 to drive it.

[0038] The position control module 2 includes a feedback control part 12 and a feedforward control part 14, both communicating with a memory 16 (schematically illustrated as a rectangle), and a summing circuit 18 communicating with the feedback control part 12 and a feedforward control part 14. Additionally, the feedback control part 12 communicates with an estimation unit 20 (schematically illustrated as another rectangle), which estimates the position and the velocity of the motor 6 based on the signals received from the three hall sensors (not shown) provided in the motor and therefrom estimates the position and the velocity of the pump actuator. The feedforward control part 14 communicates with a vacuum sensor 22 (schematically illustrated as another rectangle), which measures the vacuum generated by the pump actuator. The estimated positionMAG 11 / 24 7

[0039] and the estimated velocity of the pump actuator are fed to the feedback control part 12. For simplicity, the estimated position and the estimated velocity of the pump actuator are called measured position and measured velocity in the following.

[0040] The feedback control part 12 compares the measured position with an expected position and the measured velocity with an expected velocity of the pump actuator, wherein the expected position and the expected velocity are received from the memory and wherein the expected position is taken from the trajectory that may be stored on the memory and the expected velocity is calculated as the derivate of the expected position. The feedback control part 12 calculates a first error signal corresponding to a difference between the expected position and the measured position and a second error signal corresponding to a difference between the expected velocity and the measured velocity, multiplies the first error signal by a first factor and the second error signal by a second factor, and feeds the multiplied error signals to the summing circuit 18.

[0041] The feedforward control part 14 receives the expected velocity and the expected acceleration of the pump actuator from the memory 16 and receives the measured magnitude of the vacuum from the vacuum sensor 22, wherein the expected acceleration is calculated as the second derivative of the expected position. The feedforward control part 14 multiplies the expected acceleration of the pump actuator by a third factor and feeds it to the summing circuit 18, multiplies the expected velocity of the pump actuator by a fourth factor and feeds it to the summing circuit 18, and multiplies the measured magnitude of the vacuum by a fifth factor and feeds it to the summing circuit. The summing circuit sums all values fed into it and generates the current set point signal 8.MAG 11 / 24 8

[0042] List of reference signs

[0043] 2 position control module

[0044] 4 current control module

[0045] 6 motor

[0046] 8 current set point signal

[0047] 10 motor drive signal

[0048] 12 feedback control part

[0049] 14 feedforward control part

[0050] 16 memory

[0051] 18 summing circuit

[0052] 20 estimation unit

[0053] 22 vacuum sensor

[0054] 100 breast pump device

[0055] 110 breast pump

[0056] 112 first button

[0057] 114 second button

[0058] 120 breast shield and container assembly

[0059] 122 breast shield

[0060] 124 container

[0061] 126 controller

[0062] 130 program card

[0063] 140 tube

[0064] 150 interface

Claims

MAG 11 / 24 9CLAIMS1. A method of operating a breast pump device (100) comprising a controller (126), a motor (6) and a movable pump actuator, wherein the pump actuator is driven by the motor (6) to generate a vacuum that is applied to a breast of a lactating user via a breast shield (122) and the motor (6) is controlled by the controller (126), characterized in that the controller (126) uses a predetermined trajectory of the pump actuator to control the motor (6).

2. The method according to claim 1 , wherein the acceleration of the pump actuator is restricted to not exceed a predetermined threshold value.

3. The method according to claim 2, wherein the predetermined threshold value is 2 m / s2, 2.5 m / s2or 3 m / s2.

4. The method according to any one of claims 1 to 3, wherein the controller (126) generates a control signal to control the motor (6) based on at least one ofan expected position of the pump actuator according to the trajectory,a measured position of the pump actuator,an expected velocity of the pump actuator derived from the expected position of the pump actuator,a measured velocity of the pump actuator,an expected acceleration of the pump actuator derived from the expected position of the pump actuator, anda measured magnitude of the vacuum.

5. The method according to claim 4, wherein the controller (126) comprises a position control module (2) associated with the position of the pump actuator and a current control module (4) associated with the current to drive the motor (6) based on a current set point signal (8) generated by and received from the position control module (2), and wherein the position control module (2) includes a feedback control part (12), a feedforward control part (14) and a summing circuit (18),the feedback control part (12) compares the expected position and the expected velocity of the pump actuator with the measured position and the measured velocity of the pump actuator, calculates a first error signal corresponding to a difference between the expected position and the measured position and a second error signal corresponding to a difference between the expected velocity and the measured velocity, multiplies the first error signal by a first factor andMAG 11 / 24 10the second error signal by a second factor, and feeds the multiplied error signals to the summing circuit (18),the feedforward control part (14) receives the expected acceleration of the pump actuator, the expected velocity and the measured magnitude of the vacuum, multiplies the expected acceleration of the pump actuator by a third factor and feeds it to the summing circuit (18), multiplies the expected velocity of the pump actuator by a fourth factor and feeds it to the summing circuit (18) and multiplies the measured magnitude of the vacuum by a fifth factor and feeds it to the summing circuit (18),the summing circuit (18) sums all values fed into it and generates the current set point signal (8).

6. The method according to claim 4 or 5, wherein the measured position and the measured velocity of the pump actuator are determined by measuring a position and a velocity of the motor (6) and estimating a corresponding position and corresponding velocity of the pump actuator.

7. The method according to any one of the preceding claims, wherein the user selects a program comprised of at least one clinically tested vacuum curve from at least one set of clinically tested vacuum curves, each vacuum curve corresponding to a different trajectory of the pump actuator being stored in the breast pump device as discontinuous data points, and wherein the controller calculates the curve between the data points by interpolation and generates the corresponding trajectory of the pump actuator.

8. The method according to claim 7, wherein the curve between two adjacent discontinuous data points that have a different position value is calculated by a sinusoidal interpolation.

9. The method according to any one of the preceding claims, wherein a variation of acceleration peaks of the pump actuator resulting from any trajectory is within a predetermined range.

10. The method according to claim 9, wherein the predetermined range corresponds to a variation of a factor of three.

11. The method according to any one of the preceding claims, wherein the controller (126) is configured to adjust the brightness of a display of the breast pump device to different surrounding settings, preferably based on a signal received from an ambient light sensor.MAG 11 / 24 1112. The method according to any one of the preceding claims, wherein the controller (126) is adapted to work with a voltage input of between 9V to 24V.

13. A breast pump device (100) with a controller (126), a motor (6), a movable pump actuator and a breast shield (122), wherein the controller (126) is configured to execute the method according to any one of the preceding claims.

14. The breast pump device (100) according to claim 13, wherein the motor (6) is a brushless motor.

15. The breast pump device (100) according to claim 13 or 14, wherein the breast pump device (100) comprises a battery power supply for the motor (6).

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