PERSONAL CARE SYSTEM WITH A SET OF FUNCTIONAL UNITS

Abstract

A personal care device drive unit comprises a main body housing a motor and enabling releasable connection to any selected one of a set of different functional units. A controller of the personal care device drive unit generates an output signal associated with the selected one of the functional units connected to the main body in dependence on a sensed motor current and a sensed vibration occurring in the main body. The use of both vibration sensing and current sensing (which detects the electrical motor load resulting from driving the selected one of the functional units connected to the main body) enables multiple different functional units to be identified more reliably.

Claims

1. A personal care device drive unit, comprising a main body; a motor arranged in the main body; a connection interface arranged on the main body, adapted to enable connection of any selected one of a set of different functional units to the main body so as to enable driving of a movable functional component of the selected one of the set of different functional units by the motor; a current sensor for measuring at least one current parameter relating to an electric current driving the motor; and a controller adapted to generate an output signal associated with the selected one of the set of different functional units; characterized in that: the personal care device drive unit further comprises a vibration sensor arranged in the main body for measuring at least one vibration parameter relating to a vibration of the main body during driving of the selected one of the set of different functional units when connected to the main body; and the controller is adapted to generate the output signal associated with the selected one of the set of different functional units in dependence on a value of the at least one current parameter measured by the current sensor and a value of the at least one vibration parameter measured by the vibration sensor.

2. The personal care device drive unit as claimed in claim 1, wherein: the controller comprises a memory adapted to store a plurality of data sets; each data set of the plurality of data sets is associated with a respective one of the set of different functional units; the controller is adapted to select a data set from the plurality of data sets in dependence on the measured value of the at least one current parameter and the measured value of the at least one vibration parameter, and to generate the output signal such that the output signal relates to the selected data set.

3. The personal care device drive unit as claimed in claim 1, further comprising a speed feedback control system adapted to control a drive speed of the motor.

4. The personal care device drive unit as claimed in claim 3, wherein the speed feedback control system is adapted to implement speed control of the motor resulting in a deviation of the drive speed of the motor of less than 1% from a target drive speed.

5. The personal care device drive unit as claimed in claim 4, wherein the speed feedback control system is adapted to generate a motor speed feedback signal from the measured value of the at least one current parameter, and wherein the speed feedback control system comprises a PI controller for processing a difference between the motor speed feedback signal and the target drive speed.

6. The personal care device drive unit as claimed in claim 1, wherein the controller is adapted to: start the motor with default motor drive characteristics; and a predetermined time period after starting of the motor, generate the output signal associated with the selected one of the set of different functional units in dependence on the measured value of the at least one current parameter and the measured value of the at least one vibration parameter.

7. The personal care device drive unit as claimed in claim 1, wherein the output signal associated with the selected one of the set of different functional units is associated with predefined motor drive characteristics associated with the selected one of the set of different functional units.

8. The personal care device drive unit as claimed in claim 1, wherein the vibration sensor comprises an accelerometer.

9. The personal care device drive unit as claimed in claim 8, wherein the at least one vibration parameter comprises one or both of a vibration frequency and a vibration amplitude.

10. The personal care device drive unit as claimed in 9, wherein the controller is adapted to determine whether a maximum vibration amplitude occurring within a predefined range of vibration frequencies is above a predefined threshold value.

11. The personal care system comprising a personal care device drive unit as claimed in claim 1 and a set of different functional units each being releasably connectable to the connection interface of the main body of the personal care device drive unit and each comprising a movable functional component.

12. The personal care system as claimed in claim 11, wherein: the set of different functional units comprises at least a first and a second functional unit, each comprising a functional component configured to perform a reciprocating motion, and at least a third and a fourth functional unit, each comprising a functional component configured to perform a rotating motion in a single direction; the first and the second functional units are associated with the occurrence in the main body of a maximum vibration amplitude above, respectively, a first and a second predefined threshold value in, respectively, mutually different first and second predefined ranges of vibration frequencies; the third and fourth functional units are associated with the occurrence of a value of the at least one current parameter in, respectively, mutually different first and second predefined ranges of the at least one current parameter; the controller is adapted to generate, in a first step, an output signal associated with the first or the second functional unit when a maximum vibration amplitude occurring within, respectively, the first or the second predefined range of vibration frequencies is above, respectively, the first or the second predefined threshold value; and the controller is adapted to generate, in a second step following the first step, an output signal associated with the third or the fourth functional unit when the value of the at least one current parameter is in, respectively, said first or said second predefined range of the at least one current parameter.

13. The personal care system as claimed in claim 12, wherein the set of different functional units comprises at least a rotary-type shaving unit, a reciprocating-type precision hair trimmer, a rotary-type facial brushing unit, and a reciprocating-type beard styler.

14. The personal care system as claimed in claim 11, wherein the set of different functional units comprises at least two of a shaving unit, a facial brushing unit, a beard styler and a precision hair trimmer.

15. A method of controlling a functional unit connected to a main body of a personal care system, the personal care system comprising said main body, a motor arranged in the main body, a set of different functional units each being releasably connectable to the main body and each comprising a movable functional component, and a connection interface arranged on the main body and adapted to enable connection of any selected one of the set of different functional units to the main body so as to enable driving of the movable functional component thereof by the motor, wherein the method comprises: measuring at least one current parameter relating to an electric current driving the motor; and performing an output function associated with the selected one of the set of different functional units; characterized in that: the method further comprises measuring at least one vibration parameter relating to a vibration of the main body during driving of the selected one of the set of different functional units when connected to the main body; and the output function associated with the selected one of the set of different functional units is performed in dependence on a measured value of the at least one current parameter and a measured value of the at least one vibration parameter.

16. The method as claimed in claim 15, further comprising controlling a drive speed of the motor with a deviation of less than 1% from a target drive speed.

17. A computer program comprising computer program code means which is adapted, when said program is run on a controller of a personal care device, to implement the method of claim 15.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0059] For a better understanding of the invention, and to show more clearly how it may be carried into effect, reference will now be made, by way of example only, to the accompanying drawings, in which:

[0060] FIG. 1 shows a personal care system in the form of a shaver;

[0061] FIG. 2 shows the main body of the personal care system (which, including the components contained within the main body, may be defined as a personal care device drive unit) together with an associated set of functional units;

[0062] FIG. 3 shows an example of the possible rotational characteristics of the functional units;

[0063] FIG. 4 shows the frequency spectrum of the accelerometer x-axis signal for a beard styler connected to the handle;

[0064] FIG. 5 shows the frequency spectrum of the accelerometer x-axis signal for a precision trimmer attached to the handle;

[0065] FIG. 6 shows an example of a possible speed feedback control system;

[0066] FIG. 7 shows the resulting components of the personal care device drive unit;

[0067] FIG. 8 shows a series of measurements using different handles (of the same type) and using different functional units; and

[0068] FIG. 9 shows a two-step measurement approach graphically.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0069] The invention will be described with reference to the Figures.

[0070] It should be understood that the detailed description and specific examples, while indicating exemplary embodiments of the apparatus, systems and methods, are intended for purposes of illustration only and are not intended to limit the scope of the invention. These and other features, aspects, and advantages of the apparatus, systems and methods of the present invention will become better understood from the following description, appended claims, and accompanying drawings. It should be understood that the Figures are merely schematic and are not drawn to scale. It should also be understood that the same reference numerals are used throughout the Figures to indicate the same or similar parts.

[0071] The invention provides a personal care device drive unit, comprising a main body housing a motor, wherein a set of different functional units is each releasably connectable to the main body. A controller generates an output signal associated with a connected functional units in dependence on sensed current and a sensed vibration. The use of both vibration sensing and current sensing (which detects the electrical load resulting from the functional unit) enables multiple different functional units to be identified more reliably.

[0072] FIG. 1 shows a personal care system 10 in the form of a shaver.

[0073] The shaver comprises a functional unit 12, in particular a shaver head, releasably connected to a main body 15 (in this example the handle) via a connection interface 14. The main body, including the components accommodated within the main body is referred to in this document as the personal care device drive unit. The shaver head has a movable functional component, in this example a set of three rotary cutters 13. A motor 16 is arranged in the main body to enable driving of the movable functional component by the motor. The shaver head is just one of a set of functional units which may be connected to the main body.

[0074] A current sensor 18 is provided for measuring at least one current parameter relating to an electric current driving the motor and a vibration sensor 19 is arranged in the main body for measuring at least one vibration parameter relating to a vibration of the main body 15 during driving of the shaver head.

[0075] The current sensor 18 measures the electrical current that flows to the electrical motor 16 which drives the functional unit. The motor is typically mounted in the main body, e.g. in the handle, and the functional unit is connected to it via a rotating or translating mechanical interface. The motor current is typically an important parameter for the electronics and/or software controlling the motor, so this information is usually already available. The sensor can simply comprise a resistor, for example a surface mount component. The voltage is measured and is proportional to the current.

[0076] The vibration sensor measures mechanical vibrations of, or within, the main body. This may be implemented as an accelerometer such as a surface mount device, which is a small and inexpensive component that can be added to the main printed circuit board. In some cases, e.g. in appliances where the user interface is automatically activated upon pickup of the appliance, such accelerometers are already present and can thus be used. The position on the PCB will influence the vibration level detected. Preferably, the accelerometer is placed at a position whereby the vibration of the functional units are readily picked up.

[0077] A controller 20 generates an output signal associated with the connected functional component, i.e. the shaver head in this case, dependence on a value of the at least one current parameter measured by the current sensor and a value of the at least one vibration parameter measured by the vibration sensor.

[0078] The personal care device drive unit thus uses vibration sensing and motor current sensing to generate an output which is associated with a selected one of the different functional units. The output signal is “associated with” the connected functional unit in that the output signal is selected as relevant to, or used by, that particular functional unit. The use of both vibration sensing and current sensing (which detects the electrical load resulting from the functional unit) enables multiple different functional units to be identified. In particular, some units may use a rotary motion, and therefore induce only a small (or no) amount of vibration. Other functional units may use a reciprocating movement, so that vibrations are induced.

[0079] FIG. 2 shows the main body 15 of the personal care device drive unit, together with an associated set of functional units, each of which may be releasably connected to the main body. The functional units comprise a rotary-type shaving unit 12, a reciprocating-type precision hair trimmer 30, a rotary-type facial brushing unit 32, and a reciprocating-type beard styler 34. Each has a connection interface for cooperating with the connection interface 14 of the main body. This is one example of a hair treatment personal care system with (at least) four different functional units. More generally, the set of different functional units may comprise at least two of the different types shown.

[0080] When the personal care device drive unit is switched on, the motor speed will increase until it reaches a steady state level. Before this steady state level is reached, the current and accelerometer readings are not stable. A sufficiently stable signal can for example be obtained after a delay period, for example of between 250 ms and 500 ms. Therefore, the current sensor and accelerometer signals used to determine the output signal are for example obtained within a time period from 250 ms to 500 ms after switching on until a maximum delay for example of 1 second. Preferably, the collection and analysis of the sensor signals takes place before the user starts using the appliance.

[0081] The current sensor signal may be filtered in hardware and/or software. In software, the average current is determined starting after the delay period and for a time window for example of up to 250 ms.

[0082] The accelerometer signal may for example be sampled for example at around 1 kHz, for example at 1600 Hz. The signals of interest are vibration signals and not accelerations caused by gravity or other slow movements of the user moving the handle, so the accelerometer signal is filtered with a Band Pass or High Pass filter, for example with a a low cut-off frequency of about 30 Hz. The high cut-off frequency for a band pass filter may for example be around 200 Hz. The accelerometer is for example a 3-axis device.

[0083] The different functional units have different current and vibrational characteristics.

[0084] FIG. 3 shows an example of the possible rotational characteristics. The motor 16 is shown with a 6000 rpm rotor rotation speed. An output gear train has a step down gear ratio of 2.273 giving a rotation speed of 2640 rpm at the output shaft of the motor. Each functional unit has a different gear train, giving a rotational coupling ratio. The shaving unit 12 has a step down ratio of 1.32 giving a 2000 rpm rotation with no (or minimal) vibration. The precision trimmer 30 has a ratio of 1.0 giving a 2640 rpm reciprocal motion, giving a strong vibration signal at the corresponding frequency of 44 Hz. The rotary brush 32 has a step down ratio of 11.52 giving a 229 rpm rotation with no (or minimal) vibration. The beard styler unit 34 has a step down ratio of 0.437 giving a 5573 rpm reciprocal motion, giving a strong vibration signal at the corresponding frequency of 92.9 Hz.

[0085] There are only two vibrating functional units in this example. These are the beard styler and the precision trimmer. The shaving unit and the brush are rotating systems. Therefore, no vibration frequency is expected from those two functional units.

[0086] If feedforward control is used to control the motor speed, a deviation of +/−10% with respect to the target speed can be expected. This deviation reflects directly on the expected vibration frequency. With this level of tolerance, the precision trimmer frequency may lie in the range 39.6 Hz to 48.4 Hz and the beard styler frequency may lie in the range 83.6 Hz to 10.2 Hz.

[0087] FIG. 4 shows the frequency spectrum obtained by performing an FFT (Fast Fourier Transform) on the accelerometer x-axis signal (which is the dominant vibration axis) for a beard styler connected to the handle.

[0088] FIG. 4 shows that within the frequency window where the beard styler signal is expected, there is an amplitude peak 50. This indicates that must be a beard styler attached. However, FIG. 4 also shows an amplitude spike caused by the imbalance of the motor, at around 100 Hz (corresponding to 6000 rpm). This frequency is in the same general frequency window as the beard styler signal. In some cases the amplitude of the imbalance frequency can be sufficiently high that it appears that a beard styler is attached to the handle while actually a shaving unit is attached. This would result in a misclassification.

[0089] This motor imbalance problem is even more pronounced in the FIG. 5. The frequency spectrum is again shown based on an FFT of the accelerometer x-axis signal with a precision trimmer attached to the handle.

[0090] In this case it is not clear what is attached to the handle since in both the expected frequency window of the beard styler and the frequency window of the precision trimmer a large amplitude peak is seen. Peak 60 is in the precision trimmer window and peaks 62 and 64 are both in the general window where the beard styler signal is expected. Peak 62 is the second harmonic frequency of the precision trimmer. For example, peak 60 is at 43.5 Hz and peak 62 is at 87 Hz, with a lower amplitude that the first harmonic peak 60. The peak 64 is the motor imbalance peak. This also can result in a misclassification.

[0091] For robustness enhancement, the motor can have the speed controlled more accurately using a feedback approach. For this purpose, a digital algorithm or analogue system may be used to measure the motor speed and a digital or analogue system is used to control the motor speed accurately using feedback control.

[0092] FIG. 6 shows an example of a possible speed feedback control system. It means that vibrations caused by the motor itself (for example from slight imbalance) will give rise to known vibration parameters, which can then be filtered or ignored as not relating to a connected functional unit. Additionally, vibrating functional units that vibrate with frequencies close to each other are also better distinguishable. The speed feedback control system for example controls the motor speed with a deviation of less than 1% from a target drive speed.

[0093] A desired motor speed 70 is provided as input. It is compared with a feedback signal, and the difference is provided to a PI (proportional-integral) controller 72. The control output is the drive signal Um for the motor 16. The motor speed is detected by an encoder 74, and the encoder pulses are converted to a feedback speed signal by a pulse to speed conversion unit 76. The detection by the encoder may in fact be based on the motor current (i.e. the at least one current parameter). The motor drive current can thus be used to derive the motor speed, thereby avoiding the need for additional feedback sensors.

[0094] The speed feedback control system avoids the need for the inherent balance of the motor to be improved by means of an expensive design. Such a design would also need to include the surrounding components such as the motor frame.

[0095] By controlling the deviation on the motor speed to be +/−1%, the frequency window for the beard styler example would become 91.97 Hz to 93.83 Hz. If the target speed of the motor is 6000 rpm, the imbalance frequency is at 100 Hz (+/−1%). In that case the imbalance frequency falls out of the required detection window for the beard styler and misclassification can be avoided

[0096] FIG. 7 shows the resulting components of the personal care device drive unit. Already described above are the motor 16, current sensor 18, vibration sensor 19 (i.e. accelerometer) and controller 20.

[0097] FIG. 7 shows that the controller 20 comprises a memory 40 which stores a plurality of data sets 42. Each data set of the plurality of data sets is associated with a respective one of the set of different functional units. The controller 20 selects a data set from the plurality of data sets 42 in dependence on the measured current and vibration values and then an output signal is generated based on the selected data set.

[0098] FIG. 7 also shows that the controller 20 includes a PI control algorithm 44. It also shows an output display 46.

[0099] The output signal generated by the controller 20 may be used to control the motor 16 and/or to control the display 46. Both are shown in FIG. 7. Other output devices may of course be used.

[0100] A preferred implementation has automatic control of the identified functional unit, for example a preferred motor speed, or variation of motor speed over time. Thus, once a functional unit is identified, it may be desired not to maintain the motor speed at 6000 rpm, but to implement a time-varying motor speed profile.

[0101] The initial operation at 6000 rpm (for example) may be considered to be a generic operation mode which can be applied safely to any functional unit. The initial actuation of the motor is thus with default motor drive characteristics. Once the functional unit has been identified, the output signal is generated. This may for example relate to a drive scheme which is specific to the particular functional unit.

[0102] FIG. 8 shows a series of measurements using different handles (of the same type) and using different functional units. The measurements are gathered using feedforward control. This gives about +/−10% deviation on the speed. Thus, the clustering will be even better when the feedback speed control is used.

[0103] The x-axis plots the natural logarithm of the average current measured. The y-axis plots the natural logarithm of Max1 and Max2. Max1 is the maximum amplitude found in the frequency window where the precision trimmer (PT) and nose trimmer (NT) is expected. Max2 is the maximum amplitude found in the frequency window where the beard styler (BS) is expected.

[0104] Region 80 relates to the shaving brush (BR), region 82 relates to a nose trimmer (NT), region 84 relates to the precision trimmer (PT), region 86 relates to the shaving unit and region 88 relates to the beard styler (BS).

[0105] In one example, the set of functional units comprises a brush, precision trimmer, shaving unit and beard styler. In such a case, the set of different functional units comprises a first (precision trimmer) and a second (beard styler) functional unit, each comprising a functional component (e.g. blade) configured to perform a reciprocating motion, and at least a third (shaving unit) and a fourth (brush) functional unit, each comprising a functional component (e.g. cutter disk or bristle head) configured to perform a rotating motion in a single direction.

[0106] The first and the second functional units are then associated with the occurrence in the main body of a maximum vibration amplitude above, respectively, a first and a second predefined threshold value in, respectively, mutually different first and second predefined ranges of vibration frequencies. Thus, they vibrate at different frequencies with their own characteristic amplitude. The third and fourth functional units are associated with the occurrence of a value of the at least one current parameter in, respectively, mutually different first and second predefined ranges of the at least one current parameter. Thus, they result in characteristic load current for the driving motor.

[0107] In such a case, it is sufficient to check if a large enough vibration amplitude is found in one of the two frequency windows in order to identify the first and second functional units. The controller thus determines whether a maximum vibration amplitude occurring within a predefined range of vibration frequencies is above a predefined threshold value. Thus, the controller may seek to identify a vibration with a characteristic amplitude within a certain frequency band.

[0108] In this way, the controller generates, in a first step, an output signal associated with the first or the second functional unit when a maximum vibration amplitude occurring within, respectively, the first or the second predefined range of vibration frequencies is above, respectively, the first or the second predefined threshold value. In this example, if the required amplitude was reached in the frequency window where the precision trimmer is expected, the functional unit must be a precision trimmer. If this was in the frequency window where the beard styler is expected, the functional unit must be a beard styler.

[0109] If the vibration amplitude in both frequency windows is not high enough (not higher than the expected threshold) then a brush or a shaving unit must be attached. In that case those two can be distinguished by looking at the average current level. Below a certain current threshold it must be the brush, above this threshold it must be the shaving unit.

[0110] The controller thus generates, in a second step following the first step, a control signal associated with the third or the fourth functional unit when the value of the at least one current parameter is in, respectively, said first or said second predefined range of the at least one current parameter.

[0111] A simply switch may be used to detect whether or not any functional unit is attached.

[0112] FIG. 9 shows this two-step approach graphically.

[0113] The first step is shown as 90. The vibration amplitude is measured in the two frequency windows, as shown in the graph. The first measurement identifies whether or not a precision trimmer (PT) is present, and the second measurement identifies whether or not a beard styler (BS) is present.

[0114] The second step is shown as step 92. The average current is used to distinguish between the brush (BR) and shaving unit (SU) (and optionally also a nose trimmer NT, as shown, in the case that frequency determination alone is not sufficient).

[0115] The invention may be applied to personal care systems other than shaving systems. For example it may be applied to other hair care systems such as epilator systems, or even to oral healthcare modular systems.

[0116] Variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure and the appended claims. In the claims, the word “comprising” does not exclude other elements or steps, and the indefinite article “a” or “an” does not exclude a plurality. A single processor or other unit may fulfill the functions of several items recited in the claims. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. A computer program may be stored/distributed on a suitable medium, such as an optical storage medium or a solid-state medium supplied together with or as part of other hardware, but may also be distributed in other forms, such as via the Internet or other wired or wireless telecommunication systems. If the term “adapted to” is used in the claims or description, it is noted the term “adapted to” is intended to be equivalent to the term “configured to”.

[0117] Any reference signs in the claims should not be construed as limiting the scope.