Device for detecting an actuating operation on a motor vehicle

Abstract

The invention relates to a device for detecting an actuation operation on a motor vehicle, comprising an actuation element (2; 21), the sensor device and the evaluation device (4; 24) which is coupled to a sensor device and which outputs an actuation signal as a signal function from the sensor device, the sensor device being arranged between the actuation element (2; 21) for detecting the movement of the actuating element (2; 21) during the actuation. The sensor device comprises at least one strain gauge (5, 6; 23a, 23b), the evaluation device (4; 24) is designed to detect at least one strain gauge (5, 6; 23a, 23b) and is used to evaluate a time-dependent signal pattern in the time sequence of sensor signals.

Description

Technical Field

[0001] The present invention relates to a device for detecting an actuation operation on a motor vehicle. In particular, the present invention relates to a device having an actuation element which is arranged on the motor vehicle so as to be easily accessible to a user. Background Art

[0002] The actuating element can be arranged on the motor vehicle in particular as a handle or grip or an actuating surface. The device has a sensor device, which is coupled to an evaluation device. The evaluation device receives the signal from the sensor device and, depending on the signal from the sensor device, generates an actuating signal, which is forwarded to a control system of the motor vehicle.

[0003] The sensor device is located on the actuating device to detect the deformation of the actuating element during actuation. If the user applies a force to the actuating element, this results in a deformation of the actuating element, which is converted by the sensor device into sensor signals and output to the evaluation device. If the evaluation device detects an actuation by the user based on these sensor signals, the evaluation device outputs a corresponding braking signal.

[0004] Various devices for detecting the braking of motor vehicles are known from the prior art. For example, capacitive sensors are arranged on door handles to detect contactlessly the approach of a user to the door handle. There are also systems in which deformation of an actuating element on a motor vehicle is detected, wherein the deformation is usually detected by an inductive sensor which detects the deformation of the sensor device relative to a metal object in a target object.

[0005] EP3439178A1 discloses a corresponding device. There, the inductive sensor is designed as a printed conductor coil on a printed circuit board, which interacts with a metal part arranged on the handle housing. When the handle is deformed, the distance between the inductive sensor and the metal object changes and the braking is detected. Summary of the invention

[0006] The object of the invention is to improve existing devices for detecting brake actuations of motor vehicles and to expand their possible applications.

[0007] This object is achieved by a device according to claim 1 and a method having the features of claim 10 .

[0008] According to the invention, the sensor device has at least one strain gauge which is arranged and fastened to the actuating element in order to detect deformations of the actuating element and to output a sensor signal to the evaluation device.

[0009] Strain gauges are well-established measuring devices for detecting deformations. They have a conductor track on a support, such as an adhesive foil, which is arranged between two contacts and is usually in a meandering shape. If the support together with the conductor track is applied to a substrate, in this case an actuating element, a deformation is also imposed on the support and the conductor track. As a result, the electrical resistance of the conductor path changes after the conductor path is stretched or compressed due to the deformation of the length and the deformation of the conductor path. The change in resistance is converted into a signal by a downstream circuit, for example by a Wheatstone bridge circuit. In the context of the present invention, such a circuit can be part of the evaluation device or can be inserted as a separate component between the sensor device and the evaluation device.

[0010] In principle, any commercially available strain gauge can be used within the scope of the invention. Typically, commercially available low-cost strain gauges comprise a support foil, the above-mentioned ring-shaped train meander-shaped conductor arrangement arranged on the support foil, and a cover foil. Such strain gauges can be easily arranged anywhere on the actuating element and bonded over its entire surface in a manner suitable for the functionality.

[0011] According to the invention, the evaluation device is designed to detect a temporal sequence of a sensor signal of at least one strain gauge and to evaluate the temporal signal pattern.

[0012] The evaluation device monitors the sensor signal of the strain gauge not only for exceeding a threshold value or a specific triggering threshold, but also for monitoring the time sequence of the strain gauge in order to correct complex signal sequences and assign them to an actuation signal, with the advantage that not only one actuation type of the actuation detection device is possible, but different types of actuation can be distinguished based on the detected time-resolved signal pattern. For example, a user can trigger different functions by different spatial positions and the time sequence of his or her actuation on the actuation device. The position and time sequence of the user's interaction with the actuation element are detected by the evaluation device based on the signal of at least one strain gauge and converted accordingly into an actuation signal.

[0013] If the user touches the actuating element, the touch and the corresponding deformation result in a corresponding sensor signal. For example, pulling the actuating element will result in a temporarily prolonged sensor signal, while clicking the actuating element will result in a short temporal sequence and increased resistance change and sensor signal. The evaluation device monitors the signal of at least one strain gauge until it detects that the signal sequence corresponds to a stored pattern and can therefore be assigned to an actuation request. If such an assignment is made by the evaluation device, the evaluation device outputs a corresponding actuation signal at a signal output of the evaluation device. Downstream systems in the vehicle trigger corresponding functions or further execution.

[0014] The evaluation of the time-resolved signal sequence can be monitored, for example, in such a way that the evaluation device temporarily stores the sensor signals in a buffer memory and performs pattern recognition based on the stored signal sequence data. Signal template patterns of actual actuation gestures can be determined empirically by recording signal sequences in operation of at least one strain gauge according to a specific actuation pattern and storing them as template patterns in the evaluation device.

[0015] Comparison data can be stored in the read-only memory of the evaluation device in order to specify the time at which the sensor signals a specific operating instruction. The evaluation device can also teach and store such signals in a user-specific learning mode. Simple characteristic signal sequences can be permanently stored in the evaluation device by the manufacturer, such as a longer (e.g. 0.5s-2s) pulling of the actuating element or a longer pressing of the actuating element. This pulling or pressing action of the actuation leads to a deformation of at least one strain gauge over a longer time, i.e. until the force is released again and the actuating element deforms back to its original rest position. During this time, the evaluation device detects the change in resistance and can record the duration of the actuation as well as the measured force and the direction of the force. Further actuation, such as a tap on the actuating element, leads to a transient change in the resistance of at least one strain gauge and a series of such transients can be associated with another actuation and lead to the output of another actuation signal at the signal output of the evaluation device.

[0016] In a preferred embodiment of the invention, the sensor device has at least two strain gauges arranged in the spatial direction of the actuating element for detecting different deformations. The use of at least two strain gauges arranged at different positions relative to each other in the spatial direction allows an extended evaluation of the operating effects on the actuating element. This means that more complex actuation actions can be detected.

[0017] The arrangement in different spatial directions means that an actuation which leads to a deformation of the actuating element and which is not detected by one of the strain gauges can also be detected by another strain gauge. The evaluation device detects the temporal signal characteristics of all strain gauges and evaluates them together to identify the respective characteristic signal so that the actuation signal is generated from the totality of the characteristics of the identified characteristic signals.

[0018] It is best to provide a minimum evaluation time during which the time signal curve of the strain gauge is monitored before the evaluation device performs a specified actuation signal.

[0019] By providing the above-mentioned minimum evaluation period which can be adjusted if necessary during the measurement, more complex actuation operations can also be detected and a premature determination of the actuation signal before the actuation operation has actually been completed can be avoided.

[0020] In this case, preferably a minimum evaluation time is determined for each time signal pattern as a function of each time signal detected at the beginning of a respective evaluation event of the evaluation device.

[0021] In this case, the evaluation device detects at the beginning of an evaluation event that an evaluation event can begin because the sensor of at least one strain gauge deviates from its rest value. Depending on the level and duration of the first signal, the evaluation device determines whether a longer or shorter time should be required for the evaluation. This decision is made on the basis of the sensor signals detected so far. If, For example, if a simple time-resolved signal sequence is provided for a frequent standard actuation, the minimum evaluation time can be shortened compared to a predetermined standard value. If such an actuator is used, for example, in a door handle of a vehicle and it is assumed that the door handle needs to be pressed to open the door, then when a time signal pattern is detected that indicates that the actuator on the door handle has been pressed, , the corresponding actuator can quickly output the signal in order to shorten the time delay until the door is opened. This is particularly useful in the following situations: If no further operating gestures are initiated with the pressing of the door handle. On the other hand, if a sequence which could be the beginning of a more complex operation is detected at the start of the actuation, the shortest evaluation duration is determined to be sufficient time to perform this gesture.

[0022] In a particularly preferred embodiment of the invention, the actuation element comprises at least two actuation portions which are angled relative to each other.

[0023] On the one hand, the use of actuation sections which are angled with respect to one another facilitates operation particularly for the user and, on the other hand, also facilitates a particularly flexible and spatially adaptable arrangement of the strain gauges, depending on the intended actuation direction.

[0024] Preferably, at least one strain gauge is arranged on each of the at least two angled actuation parts facing each other. With this arrangement, the strain gauges are necessarily given different spatial orientations, since the actuation parts have different spatial orientations from each other. Based on the respective signal curves, it can then be determined on which part of the angled actuation parts a tensile or compressive force is being applied.

[0025] In a preferred embodiment of the invention, the actuating element is formed with an inner support structure, which is made of elastic material, in particular metal. The strain gauges (5, 6) are attached to the inner support structure, wherein the inner support structure is covered on at least one part by a structure or a covering layer covering the strain gauges.

[0026] In this design, the strain gauge is protected against environmental influences and the supporting structure consisting of elastic material ensures that the strain gauge is stretched by the forces distributed on the strip and, on the other hand, returns each time to an unaffected rest position.

[0027] The deformation of the support structure made of metal material ensures stability and thermal homogeneity of the entire strain gauge strip. The deformation of the cover structure made of plastic material increases the feel of the actuating element for the user and is easy to clean and can withstand external environmental influences.

[0028] In another embodiment of the invention, the actuating element is formed as a flat or curved cover of the actuating device, wherein at least two strain gauges are fixed on the inner side of the actuating element.

[0029] Such a device can be arranged, for example, at the rear of the vehicle, there for example in the form of a vehicle emblem which is at the same time an actuating device for actuating the tailgate.

[0030] By arranging the strain gauges in different spatial directions, the actuation positions of different sections along the cover can also be distinguished. Depending on the point of application of the force, different temporal signal progressions and signal strengths of the sensor are detected by the evaluation device. Based on these time-dependent sensor signal progressions, it is possible to identify in which outer area of ​​the cover actuation actually occurs.

[0031] In the method according to the invention for detecting an operation on a motor vehicle, a deformation of an actuating element on the motor vehicle is detected by at least one strain gauge. Subsequently, the time sequence of the signal of the strain gauge is detected by an evaluation device. The characteristic time-dependent signal pattern of the strain gauge in the time sequence of the signal is detected by the evaluation device. The identified characteristic time-dependent signal pattern is assigned by the evaluation device to an actuation signal and the actuation signal is output by the evaluation device at a signal output of the evaluation device.

[0032] Preferably, the method takes into account two or more strain gauges, for each of which a characteristic time signal sequence is identified.

[0033] Preferably, the method according to the invention is performed with an apparatus according to the above description.

[0034] The invention will now be explained in more detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 A schematic perspective view showing a first embodiment of the present invention; Figure 2 Shows Figure 1 A cross-sectional schematic diagram of an embodiment; Figure 3shows an exemplary first signal characteristic of a strain gauge from a first embodiment during a first operation; Figure 4 shows an exemplary second signal characteristic of the strain gauge from the first embodiment during a second operation; Figure 5 and 6 shows a perspective view of a second embodiment of the present invention; Figure 7 An exploded view of a second embodiment is shown; Figure 8 The arrangement of the strain gauges in the second embodiment is schematically shown. DETAILED DESCRIPTION

[0036] Figure 1 A first embodiment of a detection device for detecting an actuation action on a motor vehicle is shown. The device comprises an actuating element 2 which in this embodiment has three angled sections facing each other. The end section facing the user 1 is angled upwards so that the user 1 can easily reach out and pull or push this section. A horizontal section is formed as a middle section and connects the end sections. An end section on the vehicle side is again angled and provides a mounting surface for connection to the motor vehicle.

[0037] Strain gauges 5 and 6 are arranged on the actuator element, such as Figure 2 As shown, the strain gauge 5 is arranged on the user-side upright end portion of the actuating element 2. The strain gauge 6 is arranged in the middle part of the actuating element 2. An evaluation device 4 is coupled to the strain gauges 5 and 6, receives the signals of the respective strain gauges and evaluates the time-dependent signal characteristics. The respective resistance is evaluated as a measure of the deformation of the strain gauge. The conversion of the resistance change into a measured value can be realized, for example, by a Wheatstone bridge circuit, but any other circuit or logic element can also be used to detect the resistance change.

[0038] Figure 2 A schematic cross-sectional view of a first embodiment is shown. Here, the actuator element 2 is shown to have a core 2a formed of an elastic metal material, which is surrounded by a plastic housing. Strain gauges 5 and 6 are bonded to the core 2a made of elastic metal. The strain gauges 5 and 6 are encapsulated and protected by the plastic material. Figure 2 Different directional forces 9a, 9b, 9c and 9d are shown, from which the actuating force can be applied to the actuator 2. Depending on the applied force, the strain gauges 5 and 6 generate different signals with a characteristic time pattern. For example, if the user 1 pulls or pushes the protruding end of the device, i.e. the end portion of the actuating element 2, the strain gauges 5 and 6 register the corresponding deformation. Tapping this portion or a series of such tappings over time leads to other sensor signals which are detected by the evaluation device 4. Figure 3 and4 An exemplary signal characteristic of the strain gauges 5 and 6 is shown, as recorded and evaluated by the evaluation device 4. Figure 3 In FIG. 1 , the signal waveform 10 a shows an example of a signal curve of the strain gauge 6 over time, while the signal curve 10 b shows an example of a signal curve of the strain gauge 5 . Figure 3 The signal curve shown is characteristic of a user 1 striking the actuating element 2 twice in succession, e.g. One side of the end portion on the user side ( Figure 2 The evaluation device 4 detects two distinct signal deflections in rapid succession and can assign a desired operating gesture and the actuation signal corresponding to this operating gesture. The signal pattern can be identified, for example, by matching this signal curve with a stored pattern. By including two strain gauges in the evaluation, the evaluation device 4 can also check the consistency of the sensor signal, thereby avoiding erroneous detections of inconsistent sensor data.

[0039] Figure 4 An exemplary signal characteristic of the strain gauges 5 and 6 of the same embodiment is shown when the user pulls the actuating element 2. In this case, the user 1 holds the actuating element 2 at its protruding end and pulls it (force along Figure 3 In this figure, it can be seen that the signal curve is Figure 3 The curves in Figure 11 are significantly different. In this example, signal 11a comes from strain gauge 6 and signal 11b comes from strain gauge 5. The signal changes from the static state to the Figure 3 In addition, the tensile force on the actuating element 2 leads to a change in the temporal characteristics of the signal; short, independent signal pulses are no longer recognizable, but both signal curves increase significantly over a longer period of time.

[0040] The evaluation device 4 assigns these signal characteristics to a different actuation gesture and thus to a different actuation request and generates a corresponding response. Figure 3 The actuation signal generated according to the signal characteristics is different from the actuation signal.

[0041] Figure 5 , 6 , 7 and 8 relate to the second embodiment example.

[0042] In this embodiment example, the device 20 is accommodated in an actuating element which is arranged, for example, at the rear of the vehicle and is provided, for example, with a manufacturer's logo.

[0043] Such a device can be used as an element of a vehicle tailgate, for example a control unit. In the present embodiment, the device has a housing 25, whose cover 21 forms the actuating element of the device. The housing 25 accommodates a circuit board with electronic components, including the evaluation device 24. A seal 22 is arranged between the actuating element 21 and the housing 25.

[0044] The housing 25 has a mounting portion by means of which the housing 25 can be secured in its mounted position in the vehicle so that the actuating element 21 faces outwardly towards the user.

[0045] Figure 8 Strain gauges 23a and 23b are shown, which are arranged in different spatial directions relative to each other on the inner side of the cover 21 and are coupled to an evaluation device 24 for signal output. The arrangement of the decentralized strain gauges 23a and 23b and their directions make it possible to distinguish the application of actuation forces in different areas on the actuation element 21. Arrows 30a, 30b and 30c represent different actions at different positions of the actuation element 21, which are converted into different signals in response to the strain gauges 23a and 23b. The evaluation device 24 detects the signal and then derives the actuation signal by pattern matching of the stored time pattern progression. Accordingly, the evaluation device 24 then transmits the command signal to the downstream system of the vehicle. In addition to being able to determine the user's position by coordination of the strain gauges 23a and 23b, it is also possible in time, as shown in the first embodiment example. For example, the user can express a first actuation request by tapping the actuation element 21 once or more, while pressing the actuation element 21 for a longer time expresses another different actuation request.

Claims

1. A device for detecting an actuation operation on a motor vehicle, the device comprising an actuation element (2; 21), a sensor device and an evaluation device (4; 24), the evaluation device being coupled to the sensor device and outputting an actuation signal as a function of a signal from the sensor device, The sensor device is arranged on the actuating element (2; 21) to detect deformation of the actuating element (2; 21) during actuation, and is characterized in that The sensor device comprises at least one strain gauge (5, 6; 23a, 23b) fixed on the actuator element for detecting deformation, and the evaluation device (4; 24) is designed to detect the time series of sensor signals of at least one strain gauge (5, 6; 23a, 23b) and to evaluate time-dependent signal patterns in the time series of the sensor signals.

2. The device according to claim 1, wherein the sensor device has at least two strain gauges (5, 6; 23a, 23b), which are fixed to the actuator element (2; 21) and arranged in different spatial directions for detecting the deformation of the actuator element (2; 21).

3. The device according to claim 1 , wherein the evaluation device (4; 24) for evaluating the time-dependent signal pattern is configured to evaluate each evaluation The event detection comprises a plurality of sensor signals within at least a predetermined minimum evaluation time and the sensor signals are evaluated during this minimum evaluation period.

4. A device according to claim 3, wherein the predetermined minimum evaluation time for each time-dependent signal pattern is determined by the evaluation device (4; 24) as a function of a plurality of time-resolved sensor signals detected from at least one strain gauge (5, 6; 23a, 23b) at the beginning of the respective evaluation event.

5. Device according to any of the preceding claims, wherein the actuating element (2) has at least two actuating portions which are angled relative to each other.

6. The device according to claim 5, wherein at least one strain gauge (5, 6) is arranged on one of at least two parts of the actuating element (2) which are angled with respect to one another.

7. A device according to any one of the preceding claims, wherein the actuating element has an internal support structure made of an elastic material (2a) to which at least one strain gauge (5, 6) is attached, wherein the inner support structure (2a) is covered in at least one portion by a structure or a covering layer covering the strain gauge.

8. The device according to claim 7, wherein the inner support structure (2a) is formed of a metallic material and the cover structure is formed of a plastic.

9. A device according to any one of claims 1 to 4, wherein the actuator element (21) is formed as a flat or curved cover of the actuator device, wherein at least two strain gauges (23a, 23b) are fixed on the inner side of the actuator element, and the strain gauges are arranged in different spatial directions for detecting deformation (21) on the actuator element.

10. A method for detecting an operation on a motor vehicle, comprising the following steps: Detecting deformation of an actuating element (2; 21) on a motor vehicle using at least one strain gauge (5, 6; 23a, 23b); obtaining a time series of signals of strain gauges (5, 6; 23a, 23b) by means of an evaluation device (4; 24); Identification of strain gauges (5, 6; 23a, 23b) characteristic time-dependent signal patterns in the time series of the signal; The evaluation device (4; 24) assigns the actuation signal to the identified Characteristic time-dependent signal patterns; The evaluation device outputs a specified actuation signal at a signal output of the evaluation device.

11. The method according to claim 10, wherein the at least two strain gauges (5, 6; The time series of signals of the actuators 23a, 23b) are evaluated by an evaluation device (4; 24) and the respective characteristic time-dependent signal patterns are detected, wherein the strain gauges (2; 21) on the actuator elements are oriented in different spatial directions.

12. The method according to any one of claims 10 or 11, wherein the method is performed using an apparatus according to any one of claims 1 to 9.

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