Device for detecting operation signals

Abstract

A device for detecting operation signals, wherein the device comprises at least two sensor apparatuses (L1, L2, L3) and a control evaluation apparatus (5), which is coupled to the sensor apparatuses (L1, L2, L3) in order to detect signals from the sensor apparatuses. The sensor apparatuses (L1, L2, L3) are coupled to one another by way of a parallel connection, and the control evaluation apparatus (5) detects the signals from the sensor apparatuses collectively via the parallel connection.

Description

[0001] Device for detecting actuation signals

[0002] The application relates to a device for detecting actuation signals. In particular, the application relates to a device having at least two sensor devices and in which a control and evaluation device is coupled to the sensor devices in order to detect signals from the sensor devices.

[0003] Corresponding devices are widespread in the prior art. For example, such devices are known from vehicle construction, particularly in the area of ​​user interfaces. Devices for detecting actuation signals are used both inside and outside vehicles. Outside, such devices for detecting actuation signals are used, for example, in door handles or hatch handles. Various types of sensor devices are used, in particular inductive sensors or capacitive sensors, but also resistive sensors. In the interior of vehicles, corresponding devices are used to control comfort functions and control functions that are available to drivers or passengers.

[0004] Control and evaluation devices are used to capture and evaluate signals from sensor devices. These devices typically contain a microcontroller and, if necessary, additional circuit components. Depending on the sensor's functionality, various evaluation options are available for controlling the sensor and capturing its signals.

[0005] The principle of passive networks is known from EP 0 207 218 A2 and EP 0 126 846 A2. A microcontroller uses a step function to excite a network containing an inductive displacement sensor as the frequency-determining element. For evaluation, the microcontroller is signaled via a comparator when a predefined value is reached. The time difference between the step excitation and the reaching of the switching threshold provides information about the size of the measuring coil.

[0006] The principle of the oscillator circuit is known from DE-OS 29 24 092 and DE 20 46 336. An inductive displacement sensor is connected to the feedback branch of an amplifier stage, thereby exciting the stage to oscillate. Analog stages with transistors or operational amplifiers, as well as digital stages with inverters or comparators can be used. For evaluation, the oscillation frequency is determined by a processor by measuring either the period of an oscillation or the number of oscillations during a predetermined time. The necessary time or frequency measurement is carried out by the microprocessor. With the first-mentioned principle, the processor is required not only to generate the step function but also to excite the passive network. The problems with the aforementioned circuit principles are the high component complexity and the negative influence of the series resistance.This series resistance must be temperature-compensated in known circuits, as this is the only way to achieve high measurement accuracy over a wide temperature range. The measured values ​​obtained with known circuits are negatively influenced by parasitic capacitances, such as those found in motor vehicles through cables, etc.

[0007] EP 0368128 A2 discloses a circuit for evaluating inductive sensors in the field of automotive engineering. It describes an oscillator circuit for evaluating inductive sensors using microprocessors.

[0008] Adapted circuits also exist for capacitive sensors, where, for example, frequency changes in resonant circuits are detected when the capacitance of a capacitor changes, or the transferred charge quantities at variable capacitors are recorded. WO 2014 / 012763 A1 discloses a vehicle door handle in which the approach of a user is detected via several capacitive sensor electrodes.

[0009] In order to be able to record actuations along extended sections of a device, e.g. along the entire extent of a door handle, several sensors are arranged on the actuation devices. The simultaneous or periodic recording of sensor data from a large number of sensor devices places a corresponding load on the control and evaluation device used, with the use of computing power and processing resources increasing with the number of sensor devices to be evaluated. The load on such a control and evaluation device depends both on the sampling rate of the measured values ​​and on the number of sensor devices to be recorded.

[0010] There is a need to design devices for detecting actuation signals in a resource-saving manner both with regard to the energy used and the number of functional components used.

[0011] The object of the invention is to provide a device for detecting actuation signals which has an optimized ratio of detection range to material and energy consumption.

[0012] This object is achieved by a device having the features of claim 1. The device according to the invention of the type mentioned at the outset is characterized in that the sensor devices are coupled to one another by a parallel circuit, and the control and evaluation device jointly detects the signals of the sensor devices via the parallel circuit.

[0013] Through the parallel connection, the control and evaluation device treats the parallel-connected sensor devices as a unit and controls them accordingly. The individual sensor devices can be located at different spatial positions within a device, particularly in different detection ranges. This arrangement and coupling is always advantageous when spatially resolved detection of the sensor data is not required, but rather only the detection of an actuation occurring somewhere within the detection range of one of the sensor devices.

[0014] A parallel connection is understood here to mean a combined parallel connection of functional units. Several separate sensor devices, each of which forms a functional unit in its own right, are arranged spatially separately in the device and electrically coupled to one another in the form of a parallel connection. A sensor device is therefore understood to be a functional element which does not require the other sensor devices for its own function, but is functionally independent of them. In the case of inductive sensors, a corresponding sensor device is formed, for example, by a coil. In the case of capacitive sensors, each corresponding sensor device is formed by a capacitor or an electrode surface, and in the case of resistive sensors, by a variable resistor.

[0015] The control evaluation device, in turn, treats the parallel-connected sensor devices as a single sensor device, thereby reducing the associated circuit network and the required resources in the control evaluation device.

[0016] In a preferred embodiment of the invention, the sensor devices are arranged on a common printed circuit board. The sensor devices are arranged offset from one another in the plane of the circuit board.

[0017] The use of a common circuit board ensures the correct positioning and spacing of the individual sensor devices. Installing a circuit board with several parallel-coupled sensor devices in a vehicle's control unit is particularly simple.

[0018] In a preferred embodiment of the invention, the sensor devices all have an identical sensor principle, wherein the sensor principle is selected from the group of resistive detection, capacitive detection, and inductive detection. According to this embodiment, for example, exclusively inductively detecting sensor devices are coupled in parallel with one another, or exclusively capacitively detecting sensor devices are coupled with one another.

[0019] In the general embodiment of the invention, it is possible to connect both inductively detecting sensor devices and capacitively detecting sensor devices in parallel and to detect the changes in the respective properties in a parallel circuit. However, the use of uniform detection principles for the sensor devices is particularly advantageous with regard to manufacturing.

[0020] As already mentioned above, the device according to the invention can be used at any location on the vehicle where user operations are to be detected. These can be control elements in the interior of the vehicle, as well as control elements, handles, or flaps on the exterior of the vehicle, in particular on its outer skin.

[0021] It is advantageous if the control evaluation device is coupled to the parallel circuit of the sensor device via a single signal channel.

[0022] By using a single signal channel of the control evaluation device, the load on the control evaluation device is considerably reduced, since the processing power available there can be concentrated on this signal channel.

[0023] In a preferred embodiment of the invention, all sensor devices are designed as inductive sensor devices which are supplied with an alternating voltage in parallel via a common oscillator circuit, wherein a frequency detector is coupled to the parallel circuit of the inductive sensors in order to detect the total frequency of the parallel circuit.

[0024] By using a common excitation system with an oscillator and a common frequency detector for all sensors connected in parallel, the number of required components is significantly reduced. Conventional inductive sensors generally each have their own oscillators and, if necessary, frequency detectors as an assembly. According to the invention, only several inductors need to be provided as a sensor device at several points in the device, with a single, common oscillator being sufficient for the supply and a common frequency detector for providing frequency information to the control and evaluation device.

[0025] The embodiment of the aforementioned type is particularly advantageous when the sensor devices consist of spiral-shaped printed conductor tracks on one or more printed circuit boards which are coupled in parallel with the oscillator circuit.

[0026] The sensor device can be designed as printed circuit tracks during the creation of the circuit board and the functional circuit before assembly and does not require any significant additional processing steps. Manufacturing is therefore particularly simple and resource-efficient.

[0027] An example of the design of inductive and capacitance sensor devices on a circuit board made of printed conductors can be found, for example, in document EP 3439178 A1. There, too, inductive sensor regions are designed as spiral-shaped conductors, each of which is separately coupled to a control and evaluation device. According to the invention, however, the spiral-shaped inductive sensor devices are jointly coupled to a control and evaluation device and are controlled and evaluated by the latter as a unified sensor.

[0028] In a preferred embodiment of the invention, both the control evaluation device and the sensor devices are accommodated in a vehicle door handle.

[0029] The invention can fully develop its advantages in vehicle door handles or hatch handles. Vehicle door handles and hatch handles often have extensive actuation areas that must be monitored by a device for detecting actuations. On the other hand, a largely standardized actuation detection system is usually sufficient, since the exact position of the actuation is not important.

[0030] The invention will now be explained in more detail with reference to the accompanying drawing. Figure 1 shows the schematic arrangement of a first embodiment of the invention in a door handle;

[0031] Figure 2 shows the first embodiment of the invention in a schematic plan view;

[0032] Figure 3 shows an exemplary circuit according to the first embodiment;

[0033] Figure 1 shows a vehicle door handle 1 into which a printed circuit board 2 is inserted. Printed conductor tracks, coils L1, L2, and L3, are arranged on the circuit board 2 as sensor arrangements at various positions on the circuit board 2. A control and evaluation device 5 with a microcontroller is also arranged on the circuit board 2. Further functional components may also be arranged on the circuit board 2; however, these are not relevant to understanding the invention here and are therefore not shown.

[0034] The inductive sensor devices in the form of coils L1, L2 and L3 detect the approach of metallic objects in their respective detection areas along the longitudinal extent of the door handle. Such metallic objects can be metallic objects that are approached from outside, such as vehicle keys, smartphones or the like, but they can also be a change in the position of metallic components in the door handle itself, for example deformations of the metallic housing of a door handle 1. If metallic objects approach one of the sensors, i.e. one of the spiral-shaped printed conductor tracks, the inductance of this sensor device changes.

[0035] Figure 2 shows a plan view of the circuit board 2 from Figure 1. In this exemplary embodiment, the control and evaluation device 5 is coupled to a driver circuit 4 which has an oscillator circuit. The sensor devices L1, L2 and L3 are coupled in parallel to this driver circuit 4. They are thus excited by a common oscillation, and changes in the overall inductance of the coil arrangements connected in parallel are detected together without being assigned to a specific coil. The control and evaluation device 5 detects the overall signal via a single channel, which signal is passed on from the driver circuit 4 to the control and evaluation device 5.

[0036] It is evident that the spatially distributed arrangement of the conductor tracks printed as spiral coils with parallel coupling and the use of a single driver circuit 4 and a single detection channel in the control-evaluation device 5 achieves a significantly improved utilization of resources with, at the same time, extended spatial detection along the entire circuit board 2.

[0037] Fig. 3 shows area 10 from Fig. 2 as an example of an electronic circuit diagram. It shows an oscillator circuit with a comparator with an open collector output and a microprocessor. A circuit of this type can be found, for example, in EP 0 368 128 A2. The example oscillator circuit has good temperature behavior, stability and accuracy with little design effort. The size of the inductances of the sensor devices LI, L2 and L3 is converted into the period of a stationary oscillation, which can be easily determined by the processor. The load on the processor depends on the sampling rate for updating a measured value and the time for determining the period. However, the parallel connection reduces the load compared to the otherwise usual individual query of inductive sensors to the evaluation of a single channel.

Claims

Patent claims 1. Device for detecting actuation signals, the device having at least two sensor devices (LI, L2, L3), a control evaluation device (5) being coupled to the sensor devices (LI, L2, L3) in order to detect signals from the sensor devices, characterized in that the sensor devices (LI, L2, L3) are coupled to one another by a parallel circuit and the control evaluation device (5) detects the signals from the sensor devices jointly via the parallel circuit.

2. Device according to claim 1, wherein the sensor devices (LI, L2, L3) are arranged on a common circuit board (2) and offset from one another in the plane of the circuit board.

3. Device according to one of the preceding claims, wherein the sensor devices (LI, L2, L3) have an identical detection principle, selected from the group of resistive detection, capacitive detection and inductive detection.

4. Device according to one of the preceding claims, wherein the control evaluation device (5) is coupled to the parallel circuit via a single signal channel.

5. Device according to one of the preceding claims, wherein the sensor devices (LI, L2, L3) are designed as inductive sensor devices which are connected in parallel via a common driver circuit (4) is supplied with an alternating voltage.

6. Device according to claim 5, wherein the sensor devices (L1, L2, L3) are formed from spiral printed conductor tracks on one or more circuit boards (2) which are coupled in parallel with the driver circuit (4).

7. Device according to one of the preceding claims, wherein the control evaluation device (5) and the sensor devices are accommodated in a vehicle handle (2).

8. Device according to claim 7, wherein the The vehicle handle is an outside door handle, in particular a fixed outside door handle.

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