Human-machine interface for contactless entry of commands by gestures

Abstract

A human-machine interface (HMI) for contactless entry of commands by gestures is proposed. The HMI comprises a capacitive sensing surface, a detection chipset connected to the electrodes of the sensing surface for determining first, second, third and fourth capacitance observables, and a processor. The processor is configured to compute a time series of position coordinates depending on the capacitance observables and is further configured to map the time series of position coordinates onto one or more commands and to output these commands. In a further aspect, the invention relates to a barrier, e.g., a door or a window, comprising such an HMI.

Description

HUMAN-MACHINE INTERFACE FOR CONTACTLESS ENTRY OF COMMANDSBY GESTURESCross-reference to related applications

[0001] The invention generally relates to human-machine interfaces (HMIs), in particular an HMI that allows a user to input commands contactlessly by gestures. In a specific aspect, the invention relates to a barrier (e.g., a door or window) with a moveable element and an HMI connected to an actuator of the movable element.Summary of the Invention

[0002] According to a first aspect of the invention, a human-machine interface for contactless entry of commands by gestures is proposed. The HMI comprises a capacitive sensing surface, comprising a first sector with a first electrode, a second sector with a second electrode, a third sector with a third electrode and a fourth sector with a fourth electrode; a detection chipset connected to the first electrode for determining a first capacitance observable, to the second electrode for determining a second capacitance observable, to the third electrode for determining a third capacitance observable and to the fourth electrode for determining a fourth capacitance observable; a processor connected to the detection chipset and configured to compute a time series of position coordinates, the position coordinates including first and second position coordinates, which, at an instant of time are computed as:X = (CX1 -CX2) / (C1 +C2+C3+C4), andY = ((CY1 -CY2) / (C1 +C2+C3+C4), where, at the instant of time:X is the first position coordinate,Y is the second position coordinate,C1 is the first capacitance observable,C2 is the second capacitance observable,C3 is the third capacitance observable,C4 is the fourth capacitance observable,CX1 is C1 +C4 or CX1 is C1 ,CX2 is C2+C3 or, when CX1 is C1 , CX2 is C3,CY1 is C1 +C2 or, when CX1 is C1 , CY1 is C2, andCY2 is C3+C4 or, when CX1 is C1 , CY2 is C4.The processor is further configured to map the time series of position coordinates onto one or more commands and to output these commands.

[0003] The first, second, third and fourth sectors may be arranged around a center of the sensing surface, the first sector being located opposite the third sector and the second sector being located opposite the fourth sector. The first, second, third and fourth sectors may be quadrants, i.e. , disk sectors with a central angle of 90°.

[0004] According to an embodiment, CX1 is C1 , CX2 is C3, CY1 is C2, and CY2 is C4. In this case, the centroid of the first electrode and the centroid of the third electrode lie on the X-axis (the axis of the X coordinates) while the centroid of the second electrode and the centroid of the fourth electrode lie on the Y-axis (the axis of the Y coordinates).

[0005] Alternatively, CX1 is C1 +C4, CX2 is C2+C3, CY1 is C1 +C2, and CY2 is C3+C4. In this case, the centroid of both the first electrode and the fourth electrode and the centroid of both the second electrode and the third electrode lie on the X-axis while the centroid of both the first electrode and the second electrode and the centroid of both the third electrode and the fourth electrode lie on the Y-axis.

[0006] The position coordinates may include third position coordinates, which, at an instant of time are computed as Z = C1 +C2+C3+C4, where Z is the third position coordinate at the instant of time.

[0007] The sensing surface may comprise one or more counter-electrodes. The one or more counter-electrodes may be grounded or floating.

[0008] The processor may be configured to carry out the mapping of the time series of position coordinates onto one or more commands by pattern recognition.

[0009] The detection chipset may comprise one or more analog-to-digital converters with at least four sensing channels connected to the first, second, third and fourth electrodes, respectively.

[0010] A second aspect of the invention relates to a barrier (e.g., a wall, a fagade, a door, a window), comprising an aperture (e.g., a doorway, a window aperture, a gate, a portal, etc.) therein, and a moveable element (e.g., a door or window leaf) by which the aperture is closed and opened, the barrier further comprising an actuator for moving the moveable element and a human-machine interface as described above, connected to the actuator for controlling its operation.

[0011] The sensing surface may be arranged on the moveable element. Additionally or alternatively, the may be arranged on an immobile part of the barrier (e.g., on a door frame or a window frame).

[0012] The barrier may comprise a transparent or translucent panel. The sensing surface may be integrated into the transparent or translucent panel. The first, second, third and fourth electrodes may be made of transparent or translucent conductive thin film material (e.g. ITO based, conductive ZnO based (AZO, GZO), silver of gold nanowires, or a conductive polymer).

[0013] In the present document, the verb “to comprise” and the expression “to be comprised of’ are used as open transitional phrases meaning “to include” or “to consist at least of”. Unless otherwise implied by context, the use of singular word form is intended to encompass the plural, except when the cardinal number “one” is used: “one” herein means “exactly one”. Ordinal numbers (“first”, “second”, etc.) are used herein to differentiate between different instances of a generic object; no particular order, importance or hierarchy is intended to be implied by the use of these expressions. Furthermore, when plural instances of an object are referred to by ordinal numbers, this does not necessarily mean that no other instances of that object are present (unless this follows clearly from context). When this description refers to “an embodiment”, “one embodiment”, “embodiments”, etc., this means that the features of those embodiments can be used in the combination explicitly presented but also that the features can be combined across embodiments without departing from the invention, unless it follows from context that features cannot be combined.Brief Description of the Drawings

[0014] By way of example, preferred, non-limiting embodiments of the invention will now be described in detail with reference to the accompanying drawings, in which:Fig. 1 : is a schematic illustration of a door in accordance with an aspect of the invention;Fig. 2: is an illustration of a first layout of a capacitive sensing surface;Fig. 3: is an illustration of a second layout of a capacitive sensing surface;Fig. 4: is an illustration of a third layout of a capacitive sensing surface;Fig. 5: is a diagram of a HMI according to an embodiment of the invention.Detailed Description of Preferred Embodiments

[0015] Fig. 1 schematically shows a door 10 comprising a door frame 12 delimiting an aperture, in particular a doorway 14, and a door leaf 16. The door 10 further comprises an actuator 18, such as, e.g., a motorized articulated arm, for opening and closing the door. The actuator 18 is connected to a human-machine interface 20, by which user may control operation of the door 10 with gestures, without touching it.

[0016] There has been an enormously increasing demand of touchless interaction in the recent years, catalyzed by the COVID-19 pandemic. Doors in public places, healthcare facilities, schools, etc., were identified as potential contributors to the propagation of hazardous germs. Accordingly, there is a need for touchless control of doors and also of windows. Currently, gesture sensing is normally carried out by optical means, e.g., the Kinect (trademark) camera, which for many applications is too sophisticated and / or too expensive.

[0017] The HMI 20 comprises a capacitive sensing surface 22 and a controller 24, connected to the sensing surface 22 and to the actuator 18. The sensing surface 22 is subdivided into four quadrants, each having a respective sensing electrode therein. Figs. 2-4 illustrate different, non-limiting layouts of the sensing surface 22. Each sensing electrode may be surrounded by a respective counterelectrode. However, the counterelectrodes may be optional in certain configurations. The counterelectrodes may be grounded or floating.

[0018] As illustrated in Fig. 5, the controller 24 comprises a detection chipset 28 connected to the sensing electrodes 30A, 30B, 30C, 30D for determining corresponding capacitance observables C1 , C2, C3, C4, respectively, i.e., measured physical quantities indicative of the capacitance of the respective (sensing) electrode. The capacitance of each sensing electrode increases when a conductive or dielectric moving object, e.g., a user’s hand 26, approaches it. When the object moves away from a sensing electrode, the respective capacitance decreases. The detection chipset 28 may comprise one or more capacitance-to-digital converters with at least four sensing channels connected to the first, second, third and fourth electrodes, respectively.

[0019] The detection chipset may include or be connected to a microprocessor or a microcontroller (e.g., an FPGA, an ASIC, a DSP or a CPU) that receives the capacitance observables C1 , C2, C3, C4 in digital format. The processor computes position coordinates as:X = ((C1 +C4)-(C2+C3)) / (C1 +C2+C3+C4),Y = ((C1 +C2)-(C3+C4)) / (C1 +C2+C3+C4),Z = C1 +C2+C3+C4.

[0020] It shall be noted that the capacitance observables C1 , C2, C3, C4 may change over time and, accordingly, the computed position coordinates are time dependent. The time dependency has not been expressed explicitly in order not to overload the equations. X is the first position coordinate on an axis passing through the centroid of the first electrode and the fourth electrode (taken together) and through the centroid of the second electrode and the third electrode (taken together). Y is the second position coordinate on an axis passing through the centroid of the first electrode and the second electrode (taken together) and the centroid of the third electrode and the fourth electrode lie (taken together). The time series of X and Y coordinates indicate the trajectory of a moving object, e.g., the above-mentioned hand 26, over the sensing surface 22. The Z coordinate indicates a distance between the object and the sensing surface 22.

[0021] The time series of position coordinates X, Y and Z are then mapped onto one or more commands, which are provided as outputs. The mapping of the time series of position coordinates onto one or more commands may be achieved by patternrecognition 29, including classification of the observed trajectory into the most likely among several classes. These classes preferably correspond to the different commands that the HMI may output. The pattern recognition step 29 thus translates the observed trajectories into commands. When the observed trajectory cannot be associated to a command with sufficient confidence level, the pattern recognition 29 may affect it to a class that does not correspond to a command for the actuator.

[0022] The schematic of Fig. 5 shows that the HMI 22 may include a wireless communication module 32, such as, e.g., a WiFi chipset, a Zigbee module, a Bluetooth module, etc. It should be noted, however, that the HMI may also be wired to the actuator 18 or its hardware controller 34.

[0023] It should be noted that position coordinates, in particular in the capacitive sensing surface configuration of Fig.4, could, alternatively be computed as:X = (C1 -C3) / (C1 +C2+C3+C4),Y = (C2-C4)) / (C1 +C2+C3+C4),Z = C1 +C2+C3+C4.

[0024] In this case, X is the first position coordinate on an axis passing through the centroid of the first electrode and though the centroid of the third electrode while Y is the second position coordinate on an axis passing through the centroid of the second electrode and through the centroid of the fourth electrode. The Z coordinate indicates a distance between the moving object and the sensing surface.

[0025] While specific embodiments have been described herein in detail, those skilled in the art will appreciate that various modifications and alternatives to those details could be developed in light of the overall teachings of the disclosure. Accordingly, the particular arrangements disclosed are meant to be illustrative only and not limiting as to the scope of the invention, which is to be given the full breadth of the appended claims and any and all equivalents thereof.

Claims

Claims:

1. A human-machine interface for contactless entry of commands by gestures, comprising a sensing surface comprising a first sector with a first electrode, a second sector with a second electrode, a third sector with a third electrode and a fourth sector with a fourth electrode; a detection chipset connected to the first electrode for determining a first capacitance observable, to the second electrode for determining a second capacitance observable, to the third electrode for determining a third capacitance observable and to the fourth electrode for determining a fourth capacitance observable; a processor connected to the detection chipset and configured to compute a time series of position coordinates, the position coordinates including first and second position coordinates, which, at an instant of time are computed as:X = (CX1 -CX2) / (C1 +C2+C3+C4), andY = ((CY1 -CY2) / (C1 +C2+C3+C4), where X is the first position coordinate, Y is the second position coordinate, C1 is the first capacitance observable, C2 is the second capacitance observable, C3 is the third capacitance observable, C4 is the fourth capacitance observable at the instant of time, CX1 is C1 +C4 or CX1 is C1 , CX2 is C2+C3 or, when CX1 is C1 , CX2 is C3, CY1 is C1 +C2 or, when CX1 is C1 , CY1 is C2, and CY2 is C3+C4 or, when CX1 is C1 , CY2 is C4; the processor further configured to map the time series of position coordinates onto one or more commands and to output the one or more commands.

2. The human-machine interface as claimed in claim 1 , wherein the first, second, third and fourth sectors are arranged around a centre of the sensing surface, the first sector located opposite the third sector and the second sector located opposite the fourth sector.

3. The human-machine interface as claimed in claim 2, wherein the first, second, third and fourth sectors are quadrants.

4. The human-machine interface as claimed in any one of claims 1 to 3, wherein the position coordinates include third position coordinates, which, at an instant of timeare computed as Z = C1 +C2+C3+C4, where Z is the third position coordinate at the instant of time.

5. The human-machine interface as claimed in any one of claims 1 to 4, wherein the processor is configured to carry out the mapping of the time series of position coordinates onto one or more commands by pattern recognition.

6. The human-machine interface as claimed in any one of claims 1 to 5, wherein the detection chipset comprises one or more analog-to-digital converters with at least four sensing channels connected to the first, second, third and fourth electrodes.

7. The human-machine interface as claimed in any one of claims 1 to 6, wherein CX1 is C1 +C4, CX2 is C2+C3, CY1 is C1 +C2, and CY2 is C3+C4.

8. The human-machine interface as claimed in any one of claims 1 to 6, wherein CX1 is C1 , CX2 is C3, CY1 is C2, and CY2 is C4.

9. A barrier, comprising an aperture therein, and a moveable element by which the aperture is closed and opened, the barrier further comprising an actuator for moving the moveable element and a human-machine interface as claimed in any one of claims 1 to 8 connected to the actuator for controlling operation thereof.

10. The barrier as claimed in claim 9, wherein the sensing surface is arranged on the moveable element.

11. The barrier as claimed in claim 10, wherein the sensing surface is arranged on an immobile part of the barrier.

12. The barrier as claimed in any one of claims 9 to 11 , wherein the moveable element comprises a leaf, e.g., of a door or a window.

13. The barrier as claimed in any one of claims 9 to 12, wherein the barrier comprises a transparent or translucent panel, wherein the sensing surface is integrated into the transparent or translucent panel and wherein the first, second, third and fourth electrodes are made of transparent or translucent conductive material.

14. The barrier as claimed in any one of claims 9 to 13, wherein the human-machine interface is as claimed in claims 2 to 7, taken in combination.

15. The barrier as claimed in any one of claims 9 to 13, wherein the human-machine interface is as claimed in claims 2 to 6 and 8, taken in combination.

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