TDR-based system for detecting hand touch location on an object, particularly on a steering wheel, for gesture recognition

Abstract

A method for recognizing a gesture by operating a sensing system (10), the gesture being established by a sequence of hand touch locations on an object, in particular on a steering wheel (38), the sensing system (10) comprising: at least one electrically conductive signal line (12), the at least one electrically conductive signal line (12) being arranged to extend along a portion of the surface of the object using a priori knowledge of the relationship between the distance of any portion of the at least one signal line (12) from a reference point (44) and information about the position on the object; a signal voltage source (26) operatively connected to each signal line (12); and a control and evaluation unit (28) operatively connected to each signal line (12). The method comprises at least the following steps: providing (50) a time-dependent measurement signal to a signal line (12); receiving (52) the measurement signal after being at least partially reflected by at least one portion of the signal line (12); determining (54) one or more positions of one or more portions of the signal line (12) on an object at which the one or more portions of the signal line (12) have reflected the measurement signal; comparing a plurality of obtained stored consecutively determined positions on the object with at least one predefined pattern of consecutive positions to derive (60) a measure of similarity; and providing (64) an output signal indicative of the predefined pattern of consecutive positions if the derived measure of similarity is below a predefined threshold value (Thr).

Description

Technical Field

[0001] The present invention relates to a method for recognizing a gesture established by a sequence of hand touch locations on an object, in particular on a steering wheel, a sensing system for detecting gestures on an object, in particular on a steering wheel, by performing this method, a steering wheel with gesture recognition comprising such a sensing system, and a software module for automatically performing this method. Background Art

[0002] In the field of sensor applications in motor vehicles, it is known to use sensors for so-called Handsoff Detection (HOD) systems, in which one or more sensors provide information about whether the driver has his hands on the steering wheel of the vehicle. This information can be provided as input to an automatic driver assistance system (ADAS) (e.g., adaptive cruise control (ACC)), which can prompt the driver based on the provided sensor signals and remind him or her to take control of the steering wheel again. In particular, such a HOD system can be used to support the requirements of the Vienna Convention, i.e., the driver must always maintain control of the vehicle. HOD systems can also be used in parking assistance systems or ADAS configured to evaluate driver activity at high speeds.

[0003] It is also known to employ capacitive sensors in vehicle HOD systems.

[0004] By way of example, WO 2016 / 096815 A1 proposes a planar flexible carrier for steering wheel heating and / or sensing the presence of the driver's hand on the steering wheel. The planar carrier can be used to be mounted on the rim of the steering wheel without wrinkles, and comprises a portion of a planar flexible foil having two longitudinal sides and two lateral sides, which is roughly rectangular. The length B of the lateral side is 0.96 to 1.00 times the circumference of the rim. N cut-outs per unit length are provided on each of the longitudinal sides, wherein the cut-outs of one side are positioned in a staggered manner relative to the relative cut-out portions on the opposite side. Determination of the optimal shape and size of the cut-outs is described. Further described are a heat carrier, a heating and / or sensing device, and a method for producing a heat carrier, a heating and / or sensing device.

[0005] Multi-zone HOD capacitive sensor systems are known in the art and include multiple distinct and independent sensing zones along the steering wheel. These HOD capacitive sensor systems are able to distinguish between various ways a driver is holding the vehicle's steering wheel (one hand, two hands, angular position).

[0006] For example, European patent EP 1292485 B1 describes a steering wheel for a vehicle, comprising a steering ring, a hub, and at least one spoke connecting the steering ring and the hub. On the steering ring, sensors are arranged in a distributed manner along the circumference of the steering ring, thereby extending over the entire length of the steering ring. The sensors can be configured to operate on the basis of resistance, capacitance, or inductance. The sensors are subdivided into a plurality of segments, which are arranged one behind the other in the longitudinal direction of the steering ring. Two segments of the sensor are spaced apart from each other in the longitudinal direction of the steering ring by less than a finger width, wherein a segment of the sensor is smaller than a finger width in the longitudinal direction of the steering ring. This makes it possible to reliably distinguish between a person's thumb and fingers and achieve high spatial resolution.

[0007] With this capacitive HOD system, it is only possible to detect touch location or grip hand location based on the dedicated sensor area. Position detection can only be based on the sensor area size.

[0008] The use of other sensors has also been proposed for HOD applications. WO 2019 / 086388 A1 describes a system for detecting whether at least one hand of a user is on a steering wheel. The system is typically based on time domain reflectometry (TDR) measurements. The system comprises a signal line extending from a first point to a second point and arranged along at least a portion of the surface of the steering wheel. The system further comprises a detection unit coupled to the first point. The detection unit is configured to send a time-dependent detection signal travelling along the signal line, to receive a reflected signal travelling along the signal line, and to detect the presence of a hand on the surface based on the reflected signal. Summary of the Invention

[0009] Purpose of the Invention

[0010] The object of the present invention is to provide a low-complexity sensing system that can be used to at least detect hand touch positioning on an object, in particular on a steering wheel (in particular the steering wheel of a vehicle), for recognizing a gesture established by a sequence of hand touch positioning on the object, in particular on the steering wheel.

[0011] This object is achieved by a method of recognizing a gesture established by a sequence of hand touch locations on an object, in particular on a steering wheel, a sensing system for detecting such a gesture, and a steering wheel with gesture recognition as described herein. SUMMARY OF THE INVENTION

[0013] In one aspect of the present invention, this object is achieved by a method for identifying a gesture by operating a sensing system, the gesture being established by a sequence of hand touch locations on an object, in particular on a steering wheel. The sensing system comprises: at least one electrically conductive signal line arranged to extend along a portion of the surface of the object, using a priori knowledge of the relationship between the distance of any portion of the at least one signal line from a reference point and information about the position on the object; a signal voltage source operatively connected to each signal line; and a control and evaluation unit operatively connected to each signal line.

[0014] The method comprises at least the following steps:

[0015] - providing the signal lines with a time-dependent measurement signal intended to run along the respective connected signal line by operating the signal voltage source,

[0016] - operating the control and evaluation unit to receive the measurement signal after at least partly being reflected by at least a portion of the signal line to which the measurement signal has been supplied,

[0017] - operating the control and evaluation unit to determine one or more positions on the object of one or more sections of the signal line which have at least partially reflected the measurement signal,

[0018] - stored at a certain location or locations on the object,

[0019] - repeating the aforementioned steps a predetermined number of times to obtain a plurality of stored successively determined positions on the object,

[0020] - comparing the obtained plurality of stored consecutively determined positions on the object with at least one predefined pattern of consecutive positions to derive a measure of similarity, and

[0021] - providing an output signal indicative of a predefined pattern of consecutive positions if the derived measure of similarity is below a predefined threshold.

[0022] The term "signal" as used throughout this application is to be understood as meaning an electrical signal or an electromagnetic signal. The term "(electrically) connected" as used in this application is to be understood as being electrically connected by a galvanic connection or a capacitive or inductive coupling.

[0023] Typically, the sensing system for hand position detection according to the present invention is based on time domain reflectometry (TDR), and the provided time-dependent measurement signal intended to travel along the corresponding connected signal line is suitable for TDR measurement. The signal shape of the time-dependent measurement signal may depend on the specific application.

[0024] The provided time-dependent measurement signal will travel along the corresponding connected signal line and will be at least partially reflected from any impedance discontinuities along the signal line. Such impedance discontinuities can be temporarily generated by the operator's hand or one or more fingers of a hand positioned near an object (in particular a steering wheel) of the signal line. The nature of the generated one or more impedance discontinuities is determined by the nature of the hand positioning on the object (in particular on the steering wheel).

[0025] The proposed sensing system utilizes a priori knowledge of the relationship between the distance of any portion of at least one signal line from a reference point and information about the location on the object, enabling the location of a detected impedance discontinuity on the object to be determined. This information can be used to determine hand location scenarios on the object, such as hand touch location.

[0026] The proposed method allows for high-resolution position detection of a sequence of hand touch locations using the principle of time domain reflectometry (TDR). By comparing a plurality of successively determined positions with at least one predefined pattern, it is possible to recognize a gesture established by the sequence of hand touch locations on an object.

[0027] The gestures to be recognized by the proposed method can be assigned to a plurality of different additional functions, for example, comfort functions such as multimedia functions. The sequence of hand touch positioning to establish the gesture can be performed by one or both hands of the operator of the object. Hand touch positioning can include, but is not limited to, single-touch positioning using one or both hands, multiple-touch positioning using one or both hands, and hand grasping positioning using one or both hands.

[0028] Preferably, the step of comparing comprises comparing the obtained plurality of stored consecutively determined positions with a plurality of predefined patterns of consecutive positions to derive a measure of similarity for each of the plurality of predefined patterns. In this way, a plurality of gestures formed by different sequences of hand touch positioning on an object can be distinguished and recognized in a reliable manner.

[0029] Preferably, the execution of the steps of the proposed method can be enabled or disabled by parameter settings in the sensing system. In this way, the same sensing system can be used with or without gesture recognition functionality. Preferably, the parameter settings in the sensing system are designed as software parameter settings within the control and evaluation unit.

[0030] In a preferred embodiment of the method, the step of repeating the aforementioned steps comprises repeating the steps a predetermined number of times, the predetermined number corresponding to a time period between 0.5 seconds and 1.5 seconds. In this way, a high reliability for the recognition of the gesture can be achieved. Furthermore, the method can allow for the recognition of complex gestures performed by an operator or user of the object (particularly a steering wheel) within the described time period.

[0031] Preferably, the object is formed by the rim of a steering wheel, and at least one predefined pattern of consecutive positions includes turning points in the circumferential direction of the rim of the steering wheel. In this way, gestures established by hand touch positioning including back and forth wiping can be reliably detected.

[0032] In another aspect of the invention, a sensing system is provided for detecting a gesture established by a sequence of hand touch locations on an object, in particular the rim of a steering wheel.

[0033] The sensing system comprises at least one electrically conductive signal line, a signal voltage source and a control and evaluation unit.

[0034] Using a priori knowledge about the relationship between the distance of any part of the at least one signal line from a reference point and information about the position on the object, the at least one conductive signal line can be arranged to extend along a part of the surface of the object, in particular the rim of the steering wheel.

[0035] A signal voltage source is operatively connected to each signal line and is configured to provide a time-dependent measurement signal to travel along the respective connected signal line.

[0036] A control and evaluation unit is operatively connected to each signal line and is configured to:

[0037] - receiving the measurement signal after at least partial reflection by at least a portion of the signal line to which the measurement signal has been supplied,

[0038] - determining one or more positions on the object of one or more sections of the signal line, which one or more sections of the signal line have at least partially reflected the measurement signal,

[0039] - stored at a certain location or locations on the object,

[0040] - repeating the aforementioned steps a predetermined number of times to obtain a plurality of stored successively determined positions on the object,

[0041] - comparing the obtained plurality of stored consecutively determined positions on the object with at least one predefined pattern of consecutive positions to derive a measure of similarity, and

[0042] - providing an output signal indicative of a predefined pattern of consecutive positions if the derived measure of similarity is below a predefined threshold.

[0043] The phrase "configured to" as used in this application should particularly be understood as specifically programmed, arranged, equipped or arranged.

[0044] The proposed sensing system for hand position detection on an object, in particular on a steering wheel, may be of low complexity and capable of distinguishing various gestures, each of which is built up from a sequence of hand touch positions on the object.

[0045] The time-dependent measurement signal can be a pulsed signal, as is often used in TDR, but can also be a continuous signal. In a preferred embodiment of the sensing system, the signal voltage source is configured to provide a pulse-shaped signal, a frequency-swept signal, a pseudo-random phase-shift keying signal, or a pseudo-random signal. This provides design freedom for appropriate coverage of a wide range of applications.

[0046] In the case of a frequency swept sine wave, the control and evaluation unit can be configured to apply a Fast Fourier Transformation (FFT) to the received reflected measurement signal. In the case of a pseudo-random phase shift keying signal or a pseudo-random signal, the control and evaluation unit can be configured to apply a cross correlation between the provided measurement signal and the received reflected measurement signal.

[0047] Preferably, the proposed sensing system forms part of a steering wheel of a motor vehicle, and the object is formed by the rim of the steering wheel. The term "motor vehicle" as used in this patent application is to be understood in particular to cover passenger cars, trucks, semi-trucks and buses, but application to other vehicles, such as aircraft or ships, is also envisaged within the scope of the invention.

[0048] In yet another aspect of the present invention, a steering wheel with gesture recognition via hand touch location detection is provided. The steering wheel includes an embodiment of the sensing system disclosed herein, wherein at least one conductive signal line is arranged to extend along a portion of the surface of the steering wheel rim. The benefits described in the context of the sensing system according to the present invention are fully applicable to the proposed steering wheel.

[0049] In particular, the proposed steering wheel may be advantageously applied in the automotive sector; ie for use in vehicles. However, within the scope of the invention it is also envisaged to use the proposed steering wheel in aircraft and marine vehicles.

[0050] In a preferred embodiment, the steering wheel further comprises at least one continuous portion of a rim of the steering wheel, the at least one continuous portion being identifiable by external markings (i.e., identifiable to an operator of the steering wheel), wherein one or more portions of the at least one signal line are arranged on the at least one continuous portion of the rim that can be dedicated for gesture recognition, and wherein the at least one continuous portion defines one or more travel time intervals of the measurement signal along the signal line. In this way, the effort of detecting the location of a hand touch for gesture recognition can be reduced by focusing on the one or more travel time intervals of the measurement signal defined by the position of the at least one continuous portion of the rim.

[0051] Furthermore, the locations on the rim of the steering wheel at which the operator can provide inputs by way of a human machine interface (HMI), for example for selecting or adjusting comfort functions such as multimedia functions, are clearly defined and easily recognizable.

[0052] Preferably, one or more sections of at least one signal line are switchable for one or more dedicated and defined travel time intervals for gesture recognition. In this way, the same signal line design can be used with or without gesture recognition functionality, which can simplify the assembly process of the steering wheel.

[0053] In a preferred embodiment of the steering wheel, the dedicated function can be switched by a parameter setting in the control and evaluation unit. Thus, it is possible to incorporate the dedicated function after the steering wheel has been installed or even as part of a retrofit (e.g., an upgrade without any hardware changes).

[0054] Preferably, the parameter settings in the sensor system are designed as software parameter settings in the control and evaluation unit, whereby special adaptations for gesture recognition can be easily performed at any time.

[0055] In a preferred embodiment of the steering wheel, one or more portions of at least one signal line arranged on at least one continuous portion of the rim of the steering wheel are selectively usable at one point in time for gesture recognition and at another point in time for use as part of at least one signal line for time domain reflectometry-based measurements of an embodiment of the sensing system disclosed herein, which is to be used for hand positioning detection on the steering wheel.

[0056] In other words, at least one signal line can be used as a whole with an appropriate sensing system that is used for hand location detection (i.e., touch location or grip hand location) at one time, and at another time with one or more portions of at least one signal line that are arranged on at least one continuous portion of the rim dedicated to gesture recognition. In this way, the sensing system and the at least one signal line can be used substantially simultaneously to provide the safety function of non-interference detection and to provide additional functions, such as, for example, comfort functions such as multimedia functions.

[0057] In yet another aspect of the present invention, a software module for controlling the automatic execution of the steps of the embodiments of the method disclosed herein is provided.

[0058] The method steps to be performed are converted into program code of a software module, wherein the program code can be implemented in a digital memory unit of the sensing system disclosed herein and can be executed by a processor unit of the sensing system disclosed herein. Preferably, the digital memory unit and / or the processor unit can be a digital memory unit and / or a processing unit of a control and evaluation unit of the sensing system. The processor unit can alternatively or additionally be another processor unit that is specifically assigned to perform at least some of the method steps.

[0059] The software module may enable robust and reliable execution of the method and may allow rapid modification of method steps.

[0060] These and other aspects of the invention will be apparent from and elucidated with reference to the embodiments described hereinafter.

[0061] It should be pointed out that the features and measures detailed individually in the foregoing description can be combined with one another in any technically meaningful manner and represent further embodiments of the invention. The description particularly characterizes and explains the invention in detail in conjunction with the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] Further details and advantages of the present invention will become apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings, in which:

[0063] Figure 1 Schematically shows a sensing system according to the invention for detecting, in the installed state, a gesture built up from a sequence of hand touch locations on an object formed by the rim of a steering wheel,

[0064] Figure 2 Schematically shows the Figure 1 The conductive signal lines of the sensing system,

[0065] Figure 3Schematically illustrates the scene in which the hand performs a gesture according to Figure 1 a sensing system, the gesture being established by a sequence of hand touch locations on the steering wheel, and

[0066] Figure 4 By operating according to Figure 1 A flow chart of a method for a sensing system to recognize a gesture established by a sequence of hand touch locations on a steering wheel.

[0067] In the different figures, identical components are always provided with the same reference numerals or numbers, respectively. Therefore, they are usually only described once. DETAILED DESCRIPTION

[0068] Figure 1 A schematic diagram of a sensing system according to the invention is shown for detecting, in the installed state, a gesture formed by a sequence of hand touch locations on an object formed by a steering wheel (more specifically, its rim). For the sake of clarity, only the rim 40 or steering ring of the steering wheel 38 is shown, which also includes at least one spoke that connects the rim 40 to the steering column via a hub in a manner known per se. The steering wheel 38 can be used in vehicles designed as passenger cars, but can also be used in aircraft or ships.

[0069] The sensing system 10 comprises an electrically conductive signal line 12 , a signal voltage source 26 and a control and evaluation unit 28 .

[0070] The signal line 12 of the sensing system 10 is schematically shown in FIG. Figure 2 The signal line 12 can be formed into a meander pattern comprising a plurality of semicircular turns connected by straight sections. The signal line 12 can be designed as a coplanar waveguide having a conductive center line and two conductive return lines, wherein the two conductive return lines are arranged on either side of the center line in an equidistant manner. The center line and the return lines can be attached to a flexible dielectric carrier 14 such as a polymer foil, for example, by applying a screen printing method. In this way, the signal line 12 is designed to have a predefined uniform characteristic impedance, which can be arranged by varying the geometry and relative positions of the center line and the return lines, as is well known in the art.

[0071] The flexible dielectric carrier 14 may be supported by a conductive ground plane that serves as an additional return line for the coplanar waveguide.

[0072] The signal line 12 may be open-ended, such as Figure 2 , but the signal line 12 can also be terminated by a lumped impedance equal to the characteristic impedance to avoid reflections at its end. In the case of an open port, total reflection is expected, which can be used as a time reference marker.

[0073] The maximum dimension between adjacent turning points 16 of the zigzag pattern of the signal line 12 is adapted to the circumferential length of the cross-section of the rim 40 of the steering wheel 38 such that the maximum lateral dimension between adjacent turning points 16 of the zigzag pattern is greater than 25% and less than 50% of the circumferential length of the cross-section of the rim 40 of the steering wheel 38, and in this particular embodiment may be approximately 30% of the circumferential length.

[0074] like Figure 1 , the conductive signal line 12 is arranged to extend along a portion of the surface of the rim 40 of the steering wheel 38. The signal line 12 includes a first portion 18 that is arranged to extend along a portion of a surface 20 of the rim 40 of the steering wheel 38 that faces the operator of the steering wheel 38 (i.e., typically the driver of the vehicle). The signal line 12 also includes a second portion 22 that is arranged to extend along a portion of a surface 24 of the rim 40 of the steering wheel 38 that faces away from the operator of the steering wheel 38. The first portion 18 and the second portion 22 of the signal line 12 are electrically connected in series without an impedance discontinuity.

[0075] Using a priori knowledge of the relationship between the distance of any portion of the signal line 12 from the reference point 44 and information about the position on the rim 40, the signal line 12 is mounted and arranged on the surface of the rim 40 of the steering wheel 38. Any point of the signal line 12 can be selected as the reference point. In this particular embodiment, the reference point 44 is selected to be located at the input end of the signal line 12. The position of any portion of the signal line 12 on the rim 40 can be defined by specifying a surface (i.e., the surface 20 facing the operator or the surface 24 facing away from the operator) and by specifying a center angle relative to a zero angular position.

[0076] The steering wheel 38 also includes a continuous portion 46 of the rim 40 that can be identified to the steering wheel operator by external markings. A portion of the signal line 12 is arranged on the continuous portion 46 of the rim 40 that can be dedicated to gesture recognition. The continuous portion 46 defines the travel time interval of the measurement signal along the signal line 12 relative to the reference point 44.

[0077] The signal voltage source 26 is operatively connected to the signal line 12 and is configured to provide a time-dependent measurement signal to be passed along the connected signal line 12. In this embodiment, the signal voltage source 26 is designed as an integral part of the control and evaluation unit 28, thereby sharing the same housing to improve signal processing and control of the control and evaluation unit 28. In other embodiments, the signal voltage source 26 can be designed as a separate unit with appropriate signal and control lines to the signal line 12 and the control and evaluation unit 28.

[0078] In this particular embodiment, the signal voltage source 26 is designed to provide a pulse shaped signal, but in other embodiments, the signal voltage source may be configured to provide a frequency swept signal, a pseudo-random phase shift keyed signal, or a pseudo-random signal.

[0079] The control and evaluation unit 28 is operatively connected to the signal line 12 and the signal voltage source 26. The control and evaluation unit 28 may include a microcontroller including a digital data memory unit 32, a processor unit 30 for accessing data from the digital data memory unit 32, and a control interface 34. As will be explained below, the control and evaluation unit 28 is configured to automatically perform a method for recognizing a gesture established by a sequence of hand touch positions on a steering wheel 38.

[0080] The portion of the signal line 12 arranged on the continuous portion 46 of the rim 40 can be dedicated to gesture recognition by means of software parameter settings in the control and evaluation unit 28. By setting appropriate software parameters, the travel time interval of the measurement signal defined by the continuous portion 46 of the rim 40 along the signal line 12 relative to the reference point 44 will be assigned by the control and evaluation unit 28 to gesture recognition.

[0081] That is, the portion of the signal line 12 disposed on the continuous portion 46 of the rim 40 of the steering wheel 38 may be selectively usable at one point in time for gesture recognition and, at another point in time, may be selectively usable as the portion of the signal line 12 to be used for time domain reflectometry-based measurements of the sensing system 10 to be used for hand position detection on the steering wheel for HOD purposes, and in particular for distinguishing between touch position and hand grip position. This is not noticeable to the steering wheel operator due to the speed of operation of the sensing system 10.

[0082] If the software parameters are not set appropriately, the portion of the signal line 12 that is arranged on the continuous portion 46 of the rim 40 of the steering wheel 38 will always be used for time domain reflectometry-based measurements of the sensing system to be used for hand positioning detection on the steering wheel 38 for HOD purposes. Therefore, the same sensing system hardware can be used to achieve both purposes.

[0083] In the following, reference will be made to Figure 1 and Figure 3 as well as Figure 4 Description by operation according to Figure 1 An embodiment of a method of sensing system 10 to recognize a gesture established by a sequence of hand touch locations on an object formed by steering wheel 38 (more specifically, by rim 40 of steering wheel 38), wherein Figure 3 Schematically shows the situation in which a hand performs a gesture established by a sequence of hand touch locations on a steering wheel according to Figure 1 The sensing system, Figure 4 A flow chart of the method is provided. When preparing to operate the sensing system 10, it should be understood that all units and devices involved are in an operational state and as Figure 1 Configuration shown.

[0084] To enable the method to be automatically executed, the control and evaluation unit 28 includes a software module 36. The method steps to be executed are converted into program code in the software module 36. The program code is implemented in a digital data memory unit 32 of the control and evaluation unit 28 and can be executed by the processor unit 30 of the control and evaluation unit 28. Alternatively, the software module 36 can also reside in another control unit of the vehicle and be executed by it, and a data communication unit established between the control and evaluation unit 28 and the vehicle control unit will be used to achieve mutual data transmission.

[0085] The execution of the method can be enabled or disabled by appropriate setting of software parameters in the control and evaluation unit 28 .

[0086] In a first step 50 of the method, a time-dependent measurement signal is provided to the signal line 12 by operating the signal voltage source 26. The measurement signal is intended to travel along the connected signal line 12. In the absence of any hand positioning on the steering wheel 38 and the termination of the signal line 12 with a lumped impedance, a complete absence of reflections is expected. The provision of the time-dependent measurement signal can be controlled by the control and evaluation unit 28. In other embodiments, the provision of the time-dependent measurement signal can serve as a trigger signal for the control and evaluation unit 28 to start executing subsequent steps.

[0087] In a further step 52 of the method, the control and evaluation unit 28 is operated to receive the measurement signal after being at least partially reflected by at least a portion of the signal line 12 (also referred to as received reflected measurement signal).

[0088] In a next step 54, the control and evaluation unit 28 is operated to determine the position of the portion of the signal line 12 which has at least partially reflected the measurement signal on the wheel rim 40. This is done by using the distance ( Figure 2 ) and information about the position on the rim 40 ( Figure 3 ) is obtained based on the prior knowledge of the relationship between

[0089] Due to the software parameter settings in the control and evaluation unit 28, the determined position on the rim 40 corresponding to the travel time of the measurement signal within the travel time interval defined by the continuous section 46 of the rim 40 is regarded by the control and evaluation unit 28 as being generated by a hand touch positioning on the steering wheel 40, which is part of a sequence of hand touch positionings that establish a gesture.

[0090] In a further step 56 of the method, the determined position on the continuous section 46 of the rim 40 is stored in the digital data memory unit 32 .

[0091] The steps 50-56 of providing the measurement signal to the signal line 12, receiving the measurement signal after reflection, determining the position of the portion of the signal line 12 that reflects the measurement signal, and storing the determined position are repeated a predetermined number of times. The predetermined number of times corresponds to a time period that can be between 0.5 seconds and 1.5 seconds, and in this particular embodiment, the predetermined number of times can be selected to be 1.0 seconds. During this time, the steering wheel operator can perform a gesture, which can include a wiping gesture back and forth across the continuous portion 46 of the wheel rim 40.

[0092] Thus, a plurality of stored, consecutively determined positions on the rim 40 is obtained. In a further step 58, the plurality of stored, determined positions is retrieved from the digital data storage unit 32. In a next step 60, the plurality of stored, determined positions is compared with a predefined pattern of consecutive positions to derive a measure of similarity. The predefined pattern of consecutive positions includes turning points with respect to the circumferential direction of the rim 40.

[0093] In a further step 62, the derived measure of similarity is compared with a predefined threshold value Thr. If the derived measure of similarity is below the predefined threshold value Thr, then in a further step 64, an output signal is provided by the control and evaluation unit 28, which output signal indicates a predefined pattern of consecutive positions, which in turn represents a specific gesture. If the derived measure of similarity is equal to or greater than the predefined threshold value Thr, a plurality of stored determined positions are compared with another predefined pattern of consecutive positions to derive another measure of similarity. This is repeated until the derived measure of similarity is below the predefined threshold value Thr for one of the predefined patterns of consecutive positions, or until a plurality of stored consecutive determined positions fails to match any of the predefined patterns of consecutive positions.

[0094] While the invention has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive; the invention is not limited to the disclosed embodiments.

[0095] Other variations of the disclosed embodiments may be understood and effected by those skilled in the art in practicing the claimed invention by studying 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 intended to represent at least two. The 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. Any reference signs in the claims should not be construed as limiting the scope.

[0096] Reference Signs List

[0097] 10 Sensing System

[0098] 12 signal lines

[0099] 14 Flexible dielectric carrier

[0100] 16 Turning Point

[0101] 18 Part 1

[0102] 20 Surface

[0103] 22 Part 2

[0104] 24 Surface

[0105] 26 Signal voltage source

[0106] 28 Control and evaluation units

[0107] 30 processor units

[0108] 32 digital data memory cells

[0109] 34 Control Interface

[0110] 36 software modules

[0111] 38 Steering wheel

[0112] 40 rim

[0113] 42 hands

[0114] 44 reference points

[0115] 46 Continuous Section

[0116] Thr predefined threshold

[0117] step:

[0118] 50 Provides measurement signal to signal line

[0119] 52 Receive reflected measurement signal

[0120] 54 Determine the position of the portion of the signal line that reflects the measurement signal on the wheel rim

[0121] 56 The determined position on the rim is stored in the digital data storage unit

[0122] 58 Retrieve the stored determined position on the rim from the digital data storage unit

[0123] 60 Derive a measure of similarity by comparing to a predefined pattern of consecutive positions

[0124] 62 Compare the similarity measure to a predefined threshold

[0125] 64 Provides output signals indicating predefined patterns

Claims

1. A method for recognizing a gesture by operating a sensing system (10), said gesture being established by a sequence of hand touch locations on an object, said sensing system (10) comprising: at least one conductive signal line (12) arranged to extend along a portion of a surface of the object using a priori knowledge of a relationship between a distance of any portion of the at least one signal line (12) from a reference point (44) and information about a position on the object; a signal voltage source (26) operatively connected to each signal line (12); and a control and evaluation unit (28) operatively connected to each signal line (12), the method comprising at least the following steps: - providing (50) the signal line (12) with a time-dependent measurement signal intended to run along the respective connected signal line (12) by operating the signal voltage source (26), - operating the control and evaluation unit (28) to receive (52) the measurement signal after at least partly being reflected by at least a portion of the signal line (12) to which the measurement signal has been supplied, - operating the control and evaluation unit (28) to determine (54) one or more positions on the object of one or more sections of the signal line (12) at which one or more sections of the signal line (12) have at least partially reflected the measurement signal, - storing (56) the determined position or positions on the object, - repeating the aforementioned steps (50, 52, 54, 56) a predetermined number of times to obtain a plurality of stored successively determined positions on said object, - comparing the obtained plurality of stored consecutively determined positions on the object with at least one predefined pattern of consecutive positions to derive (60) a measure of similarity, and - If the derived measure of similarity is below a predefined threshold value (Thr), providing (64) an output signal indicative of a predefined pattern of said consecutive positions.

2. The method according to claim 1, wherein The execution of the steps (50-52, 60, 64) can be enabled or disabled by parameter settings in the sensing system (10).

3. The method according to claim 1 or 2, wherein: The step of repeating the aforementioned steps (50, 52, 54, 56) includes repeating the steps (50, 52, 54, 56) a predetermined number of times, the predetermined number of times corresponding to a time period between 0.5 seconds and 1.5 seconds.

4. The method according to claim 1 or 2, wherein: The object is formed by a rim (40) of a steering wheel (38), and wherein at least one predefined pattern of consecutive positions comprises turning points with respect to a circumferential direction of the rim (40) of the steering wheel (38).

5. A sensing system (10) for detecting a gesture, the gesture being established by a sequence of hand touch locations on an object, comprising: at least one electrically conductive signal line (12) which can be arranged to extend along at least a portion of a surface of the object using a priori knowledge of the relationship between the distance of any portion of the at least one signal line (12) from a reference point (44) and information about the position on the object, a signal voltage source (26) operatively connected to each signal line (12) and configured to provide a time-dependent measurement signal to be passed along the respective connected signal line (12), and - a control and evaluation unit (28) operatively connected to each signal line (12) and configured to: receiving (52) the measurement signal after being at least partially reflected by at least a portion of the signal line (12) to which the measurement signal has been supplied, determining (54) one or more positions on the object of one or more portions of the signal line (12) at which one or more portions of the signal line (12) have at least partially reflected the measurement signal, storing (56) the determined position or positions on the object, repeating the aforementioned steps (52, 54, 56) a predetermined number of times to obtain a plurality of stored successively determined positions on said object, comparing the obtained plurality of stored consecutively determined positions on the object with at least one predefined pattern of consecutive positions to derive (60) a measure of similarity, and • If the derived measure of similarity is below a predefined threshold value (Thr), providing (64) an output signal indicative of a predefined pattern of said consecutive positions.

6. A steering wheel (38) with gesture recognition by hand touch location detection, comprising the sensing system (10) according to claim 5, wherein: The object is formed by a rim (40) of the steering wheel (38), and the at least one electrically conductive signal line (12) is arranged to extend along a portion of the surface of the rim (40) of the steering wheel (38).

7. The steering wheel (38) of claim 6, further comprising at least one continuous portion (46) of the rim (40) of the steering wheel (38), the at least one continuous portion (46) being identifiable by external markings, wherein One or more sections of the at least one signal line (12) are arranged on the at least one continuous section (46) of the rim (40) that can be dedicated to gesture recognition, and wherein the at least one continuous section (46) defines one or more travel time intervals of the measurement signal along the signal line (12).

8. The steering wheel (38) according to claim 7, wherein The one or more portions of the at least one signal line (12) are switchable for the dedicated and defined one or more travel time intervals for gesture recognition.

9. The steering wheel (38) according to any one of claims 7 or 8, wherein: The dedicated mode can be switched by parameter setting in the control and evaluation unit (28).

10. The steering wheel (38) according to any one of claims 7 or 8, wherein The one or more portions of the at least one signal line (12) arranged on the at least one continuous portion (46) of the rim (40) of the steering wheel (38) are selectively usable for gesture recognition at one point in time and selectively usable as part of the at least one signal line (12) for time domain reflectometry-based measurements of a sensing system (10) according to claim 5, the sensing system (10) being used for hand positioning detection on the steering wheel (38).

11. A software module (36) for controlling the automatic execution of the method according to any one of claims 1 to 4, wherein: The method steps to be performed are converted into program code of the software module (36), wherein the program code can be implemented in a digital data memory unit (32) of the sensing system (10) according to claim 5 or a separate control unit and can be executed by a processor unit (30) of the sensing system (10) according to claim 5 or a separate control unit.

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