Device for interference-free detection of contact with a steering handle

Abstract

Device (1) for interference-free detection of a touch of a steering handle (2) by a user, with at least one touch sensor (11, 12) for touch detection, at least one disturbance sensor (21, 22) for disturbance detection and an evaluation unit (31) which is connected and configured to the sensors (11, 12, 21, 22) in terms of signal transmission, to determine a value for touch detection from measured values ​​acquired by the sensors (11, 12, 21, 22) that is corrected for disturbances, wherein at least one disturbance sensor (21, 22) is designed to receive frequencies as disturbances.

Description

[0001] The invention relates to a device for the error-free or interference-free detection of a contact with a surface, in particular a surface of a steering handle of a vehicle.

[0002] A variety of surfaces and steering handles are known from the state of the art on which a touch is to be detected.

[0003] These touch detection systems are often based on a change in capacitance or impedance on a current-carrying electrical conductor caused by the touch.

[0004] However, the problem here is that the sensor which detects the capacitance or impedance changes, or a measuring path of the sensor, is also subject to interference, so that the recorded measured values ​​and thus the determination of the touch detection can be falsified.

[0005] Such interference or disturbances can be, for example, electromagnetic fields, such as those caused by radio signals.

[0006] Accordingly, it may happen that touches are detected even though the steering handle is not touched, or conversely, that no touch is detected even though the steering handle is touched by a user.

[0007] This is particularly disadvantageous when touch detection is used for safety functions, as is common in modern vehicles. For example, hand detection on the steering handle is often required at the time of registration for the use of autonomous or automated driving.

[0008] It is therefore desirable to improve touch detection and make it more robust and less prone to errors.

[0009] Various approaches to this are already known from the state of the art, but some of them still need to be improved.

[0010] The invention is therefore based on the object of overcoming the aforementioned disadvantages and providing a device on and with which a touch, in particular of a steering handle, by a user can be detected essentially free from interference.

[0011] This problem is solved by the combination of features according to claim 1.

[0012] According to the invention, a device for the interference-free detection of a touch of a steering handle by a user is therefore proposed according to claim 1. The device has at least one touch sensor for touch detection, at least one disturbance sensor for disturbance detection, and an evaluation unit. Accordingly, the at least one touch sensor can also be referred to as a hand detection sensor. The evaluation unit is connected to the sensors, i.e., all touch sensors and all disturbance sensors, for example via one or more measuring circuits and is designed to determine a value for touch detection, adjusted for the disturbances, from the measured values ​​detected by the sensors.To determine adjusted values, the evaluation unit can, for example, subtract the disturbance variables that correspond to the measured values ​​of the disturbance sensor from the measured values ​​of the touch sensor, which correspond to a sum of disturbance variables and the signals caused by the hand or the touch. Instead of a simple subtraction, vectorial subtraction or other suitable operations can also be used. According to the invention, it is further provided that the at least one disturbance sensor is each designed to receive frequencies as disturbance variables. Although the disturbance sensors can each receive a large number of frequencies as disturbance variables, it is preferably provided that the disturbance sensors are each designed to receive a predetermined frequency as a disturbance variable or to receive a frequency band, ie a large number of frequencies with a predetermined frequency therein, as a disturbance variable.In this case, the at least one disturbance sensor is designed in particular as an antenna line and further in particular as an open or one-sidedly open antenna line.

[0013] An advantageous variant of the invention provides that a plurality of disturbance sensors are provided for receiving a plurality of frequencies as disturbances, so that different frequencies or different frequency bands can be detected and different disturbances can be taken into account. Preferably, exactly one disturbance sensor is provided per frequency or per frequency band. Accordingly, the disturbance sensors are each designed to receive a respective predetermined frequency as a disturbance or to receive a predetermined frequency band with predetermined frequencies as disturbances. Although the different disturbance sensors are preferably each designed to detect a frequency band with a predetermined frequency therein as a disturbance, so that the predetermined frequencies of the disturbance sensors to be detected as disturbances differ, the frequency bands can overlap one another.

[0014] A variant of the invention also provides that the at least one disturbance sensor or at least some of the disturbance sensors are each designed as a separate antenna structure.

[0015] The separate antenna structure can be an electrically conductive structure applied to or etched into a circuit board with a predetermined length and / or length adapted to a frequency to be received as an interference variable. The circuit board is preferably a circuit board on which the evaluation unit is also arranged, so that the separate antenna structure can be formed cost-effectively and space-savingly on the evaluation unit and is integrated with it in a common structural unit. Furthermore, the antenna structure can have a predetermined course that is optimized for receiving the frequency predetermined for it and can, for example, be meander-shaped. Typically for an antenna, the structure can be open on one side, i.e. one side of the conductive structure is not electrically connected to other components.

[0016] Similar to the alternative embodiment mentioned below, however, a switching element for disconnecting the electrically conductive structure can also be provided in the antenna structure.

[0017] An alternative variant to the separate antenna structure, which can also be combined with it, provides that the at least one disturbance sensor or at least some of the disturbance sensors are each integrally formed by a detachable electrical line of an electronic component that is integrated or can be integrated into the steering handle. The electronic component can, in particular, be another sensor and, more particularly, a temperature sensor, which is already integrated into the steering handle, for example, for controlling a heater.

[0018] The electronic component or the further sensor and in particular the temperature sensor can also be connected to the evaluation unit in terms of signal technology and, for example, via one or more measuring circuits, so that the evaluation unit can record and / or evaluate the measured values ​​of the further sensor / the temperature sensor on the one hand and the measured values ​​of the disturbance sensor formed by the switchable electrical line on the other hand.

[0019] Furthermore, it can be provided that the switchable electrical line runs at least partially in a grip area or a steering wheel rim of the steering handle, so that the line is not located behind the airbag or other shielding elements, but runs outwards to the steering wheel rim and is less shielded from the interference or interference frequencies.

[0020] In combination with the detachable electrical line, the device can also comprise at least one switching element, by which the detachable electrical line can be detachable such that the line is open on one side and / or has a predetermined length adapted to a frequency to be received as a disturbance. The at least one switching element can be controlled by the evaluation unit for this purpose. Furthermore, the evaluation unit can also be connected to or disconnected from the detachable electrical line via a switching element.

[0021] For operation, the electronic component can be connected to a supply voltage or a voltage source and / or a ground via the switchable electrical line. For operation or use as a disturbance sensor, the line can be separated from the supply voltage or the voltage source and / or the ground by the at least one switching element and switched to a potential-free state. Accordingly, the supply voltage and / or the ground can be separated from the switchable electrical line, allowing it to be used as a disturbance sensor.

[0022] The switchable electrical line can also be divided into several sections, each of which is separated from one another by a further switching element, so that the sections can each be used as a disturbance sensor, or several sections together can be used as a disturbance sensor. Each of the sections can be designed, in particular by a length or a course adapted for this purpose, to receive a predetermined frequency as a disturbance or a predetermined frequency band with a frequency within it as a disturbance. Each of the sections can then be connected for signaling purposes to the evaluation unit or a measuring circuit of the evaluation unit.

[0023] Accordingly, the evaluation unit can be configured to activate the at least one switching element prior to the acquisition and evaluation of the measured values ​​of the at least one disturbance sensor, thereby enabling the at least one disturbance sensor. After, and preferably immediately after, the measured values ​​have been acquired, the disconnectable electrical line can be reconnected to the supply voltage and / or ground.

[0024] The evaluation unit can also be designed to record the measured values ​​of the sensors in parallel over time. For this purpose, the evaluation unit can be connected to or have a plurality of measuring circuits or measuring ICs, with each sensor being assigned a measuring IC, for example. However, due to the large number of measuring ICs, this leads to increased installation space requirements and higher costs. Therefore, alternatively, it can be provided that the evaluation unit is designed to record the measured values ​​of the sensors sequentially over time, i.e. one after the other. For this purpose, the evaluation unit can be connected to or have a single or exactly one measuring IC, i.e. a measuring circuit, which records the measured values ​​of the sensors one after the other.However, in order to ensure that a disturbance present at the time of recording the measured values ​​of the at least one touch sensor can be correctly recorded with the at least one disturbance sensor, it is provided that the evaluation unit is also designed to record the measured value of the at least one disturbance sensor immediately after the measured value of the at least one touch sensor has been recorded.

[0025] If several touch sensors are present, it can also be provided that the measured values ​​of a single touch sensor are recorded first and then the measured values ​​of one, all or several disturbance sensors are recorded one after the other.

[0026] One aspect of the invention also relates to a steering handle with a device according to the invention integrated therein or connected thereto or to a system comprising a steering handle and a device according to the invention.

[0027] The features disclosed above can be combined as desired, as long as this is technically possible and they do not contradict each other.

[0028] Other advantageous developments of the invention are characterized in the subclaims or are presented in more detail below, together with the description of the preferred embodiment of the invention, with reference to the figures. They show: Fig. 1 a system comprising a steering handle and a device; Fig. 2 a flow chart for recording the measured values ​​of the sensors.

[0029] Fig. 1 shows, by way of example, a schematic view of a system comprising a steering handle 2 and a device 1 according to the invention. Fig. Figure 2 shows an example of a method for determining adjusted values ​​using a device 1 according to the invention, as described for example in Fig. 1. The representation of the procedure according to Fig. 2 based on a flow chart.

[0030] The device 1 in Fig. 1 comprises two touch sensors 11, 12, which are integrated into the steering handle 2, two disturbance sensors 21, 22, and an evaluation module 30. All sensors 11, 12, 21, 22 are connected to the evaluation module 30 or a measuring circuit 32 of the evaluation module 30, and via the measuring circuit 32 to an evaluation unit 31 of the evaluation module 30. Although the evaluation unit 31 and the measuring circuit 32 are shown as two components, they can alternatively be formed integrally by a single structural unit.

[0031] The two touch sensors 11, 12 are each connected via a filter element 33 and the two disturbance sensors 21, 22 are connected without a filter element or directly to the measuring circuit 32.

[0032] The measuring circuit 32, which can be provided as a measuring IC, has an input for each of the sensors 11, 12, 21, 22, but in the present case cannot evaluate the sensors 11, 12, 21, 22 simultaneously, but only one after the other, ie sequentially, so that the measuring circuit 32 switches through the inputs or evaluates them one after the other.

[0033] In the present case, a first disturbance sensor 21 is designed as a separate antenna structure. To reduce installation space and costs, the antenna structure or the first disturbance sensor 21 is designed as a conductive structure 23 applied to the circuit board of the evaluation module 30. The length of the conductive structure 23 is adapted to a specific frequency to be received as the disturbance variable.

[0034] Since the measuring circuit 32 and the evaluation unit 31 of the evaluation module 30 are each arranged as IC on the circuit board, the evaluation module 30 can be provided as a compact unit.

[0035] Furthermore, a second disturbance sensor 22 is provided, which is integrally formed by a switchable electrical line 24, which simultaneously serves as a supply line for an electronic component 3 arranged in the steering handle 2. In this case, the electronic component 3 is a temperature sensor of a heater of the steering handle 2, which is connected to a voltage source 4 and a ground 5 via the supply line.

[0036] Since the supply line of the electronic component 3 is to be used as an open antenna line for receiving a predetermined frequency as an interference variable, two switching elements 41, 42 are provided in this case, wherein a first switching element 41 separates, i.e., disconnects, the switchable electrical line 24 from the voltage source 4 and a second switching element 42 separates, i.e., disconnects, the switchable electrical line 24 from ground 5. It is provided that the switching elements 41, 42 are arranged and separate the supply line in such a way that the switchable electrical line 24, which forms the second interference sensor 22, has a predetermined length and is accordingly also suitable for receiving a predetermined frequency.

[0037] However, the two disturbance sensors 21, 22 are adapted to two different predetermined frequencies as disturbance variables, so that different disturbance frequencies or disturbance variables can be taken into account accordingly.

[0038] To determine the adjusted values, the evaluation unit 31 of the evaluation module 30 is connected to the measuring circuit 32 so that the measured values ​​of the sensors 11, 12, 21, 22 acquired by the measuring circuit 32 can be transmitted to the evaluation unit 31. Before the measured values ​​are acquired, the evaluation unit 31 controls the switching elements 41, 42 such that they enable the switchable electrical line 24 for use as a disturbance sensor 22. After the measured values ​​of the disturbance sensor 22 have been acquired, the switching elements 41, 42 can be controlled to reconnect the temperature sensor 3 to the voltage source 4 and ground 5.

[0039] In Fig. Figure 2 illustrates an example of a method for determining adjusted values ​​using the device according to the invention. This method comprises the following steps: A Start B Collecting the measured values ​​of all touch sensors 11, 12 (collecting the measured values ​​of the i-th touch sensor) C Have all touch sensors been read or their measured values ​​recorded? No → Continue to step D; Yes → Continue to step E D Increase counter i or record the measured values ​​of the next touch sensor 11, 12 E Is (at least) one disturbance sensor 21 configured as a separate antenna structure on the circuit board present? No → Continue to step G; Yes → Continue to step F F Recording the measured values ​​of the disturbance sensors 21 designed as a separate antenna structure on the circuit board G Is (at least) one disturbance sensor 22 integrally formed by a detachable electrical line 24 present? No → Continue to step M; Yes → Continue to step H H Are switching elements 41, 42 present for disconnecting the electrical line 24? No → Continue to step J; Yes → Continue to step I I Controlling the switching elements 41, 42 so that line 24 is enabled. J Recording the measured values ​​of the disturbance sensors 22, which are designed as an integral part by a switchable electrical line 24 K Are switching elements 41, 42 present for disconnecting the electrical line 24? No → Continue to step M; Yes → Continue to step L L Controlling the switching elements 41, 42 so that the line 24 is connected to the voltage source 4 and the ground 5. M Determine the adjusted values ​​by subtracting the measured values ​​of the disturbance sensors 21, 22 from the measured values ​​of the touch sensors 11, 12. N Waiting for new measurement request / next measurement slot

Claims

[1] Device (1) for the interference-free detection of a touch of a steering handle (2) by a user, with at least one touch sensor (11, 12) for touch detection, at least one disturbance sensor (21, 22) for disturbance detection and an evaluation unit (31) which is connected to the sensors (11, 12, 21, 22) by signal technology and is designed to determine a value for touch detection adjusted for the disturbances from measured values ​​recorded by the sensors (11, 12, 21, 22), wherein the at least one disturbance sensor (21, 22) is designed to receive frequencies as disturbances. [2] Device according to claim 1, wherein a plurality of disturbance sensors (21, 22) are provided for receiving a plurality of frequencies as disturbances, wherein the disturbance sensors are each designed to receive a respective predetermined frequency as disturbance or to receive a predetermined frequency band with predetermined frequencies as disturbances. [3] Device according to claim 1 or 2, wherein at least one disturbance sensor (21) is designed as a separate antenna structure. [4] Device according to the preceding claim, wherein the separate antenna structure is an electrically conductive structure (23) applied to a printed circuit board or etched into a printed circuit board with a predetermined length and / or length adapted to a frequency to be received as an interference variable. [5] Device according to one of the preceding claims, wherein at least one disturbance sensor (22) is formed integrally by a switchable electrical line (24) of an electronic component (3) integrated into the steering handle (2). [6] Device according to the preceding claim, further comprising at least one switching element (41, 42) by means of which the switchable electrical line (24) can be switched on in such a way that the line (24) is open on one side and has a predetermined length and / or a length adapted to a frequency to be received as a disturbance variable. [7] Device according to the preceding claim, wherein the electronic component (3) for operating the electronic component (3) is connected to a voltage source (4) and / or a ground (5) via the switchable electrical line (24) and the line (24) for operating as a disturbance sensor (22) can be separated from the voltage source (4) and / or the ground (5) and switched to be potential-free by the at least one switching element (41, 42). [8] Device according to one of the two preceding claims, wherein the evaluation unit (31) is designed to control the at least one switching element (41, 42) in an enabling manner before the measured values ​​of the at least one disturbance sensor (22) are detected and evaluated. [9] Device according to one of the preceding claims, wherein the evaluation unit (31) is designed to record the measured values ​​of the sensors (11, 12, 21, 22) in parallel, or wherein the evaluation unit (31) is designed to record the measured values ​​of the sensors (11, 12, 21, 22) sequentially in time and, after the measured value of the at least one touch sensor (11, 12) has been recorded, to record the measured value of the at least one disturbance sensor (21, 22) immediately in time.

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