METHOD FOR EVALUATING A SENSOR DEVICE

Description

[0001] The invention relates to a method for evaluating a sensor device. In particular, the invention relates to a method in which a sensor device is used that has at least one proximity sensor which detects the spatial approach of bodies. The sensor device further comprises a control and evaluation unit that is coupled to the proximity sensor and which in turn has a signal output.

[0002] Sensor devices of the aforementioned type are used in motor vehicles to detect operating gestures. For example, such sensor devices with capacitive or optical proximity sensors, and occasionally also with ultrasonic or radar sensors, are used in vehicles where a vehicle function is to be triggered by the execution of an operating gesture. Operating doors or hatches, especially tailgates, can thus be largely contactless. In this context, contactless means that the operator does not have to perform any unlocking manipulation of a door lock or door handle.

[0003] The measured values ​​from the proximity sensor are evaluated using established methods to determine whether the temporal signal profile of the data output by the proximity sensor corresponds to predefined criteria that characterize a valid user request. For this purpose, a complex pattern comparison can be performed, but simple temporal characteristics of the signal profile, as well as changes in values ​​within certain time periods, can also be compared. If, for example, the proximity sensor is a capacitive sensor located in the rear of a vehicle, it is typically intended that a user must first perform a pivoting movement of their leg or foot in one direction towards the vehicle and then back again to express a user request.Such a kick sensor will accordingly perform an evaluation to determine whether the proximity sensor detects a body approaching and subsequently moving away within a certain time period. Other gestures and movements can also be used for operation. Numerous implementations for the basic recognition of such operating patterns are known in the prior art. Likewise, numerous designs for sensor devices with proximity sensors and associated control and evaluation units are known.

[0004] For example, document DE 10 2012 100 960 discloses a corresponding sensor device and an associated evaluation algorithm. An alternative design, in which a temporal signal profile of a proximity sensor is subjected to pattern recognition, can be found in DE 10 2014 100 974.

[0005] All known systems share the common feature of evaluating signal patterns from proximity sensors and, based on this evaluation, determining whether or not the user actually intends to operate the vehicle. Simultaneously with or subsequently, an authorization check can also be performed, which involves a wireless query of a vehicle key or other authentication device that the operator must carry to actually activate the vehicle function.

[0006] While the basic function of such operating devices and the procedures for their operation are now widespread and well-established, user and operator acceptance is not always satisfactory. Operators are often unsure whether they are performing an operating gesture correctly or whether the vehicle is even in a state where it detects the executed operating gesture. Numerous improvements have already been proposed to facilitate operation, such as the optical marking of an area in which the operating gesture is to be performed (see, for example, DE 10 2014 106 939).

[0007] However, such systems occasionally bring new problems, as they may require, for example, impermissible light sources on the car or lose their usefulness under unfavorable environmental conditions.

[0008] Further examples of the prior art are disclosed in DE 10 2013 110506 A1 or WO 2015 / 113554 A1.

[0009] The object of the invention is to provide an improved method which increases the ease of use of a sensor device and also enables improved operating safety.

[0010] This problem is solved by a method having the features of claim 1.

[0011] According to the invention, during the detection process of an operating event, several different signals are output at the signal output of the control and evaluation unit. This control and evaluation unit can typically be connected via its signal output to a vehicle bus system or other central control unit of a vehicle. This central control unit receives the signals from the control and evaluation unit of the sensor device and, optionally using additional signals and criteria, initiates subsequent actions, such as unlocking a door or performing other positioning procedures on the vehicle. Triggering wireless communication in response to the central control unit receiving a signal from the control and evaluation unit of the sensor device is also possible. However, these subsequent actions are not part of the invention.The response to the output signals can be individually selected by the vehicle manufacturer.

[0012] According to the invention, in addition to the second operating signal, which, according to the invention, signals the recognition of a valid operating gesture, a temporally prior first operating signal is output. If a user performs an operating gesture on the vehicle within the detection range of the sensor device and its proximity sensor, the sensor values ​​of the proximity sensor are evaluated to determine whether these values ​​represent a validly executed operating gesture. As described in the prior art, various types of pattern recognition or other evaluations can be used for this purpose. The evaluation of these signal sequences, which represent an operating gesture, such as the pivoting movement of a foot or the approach of a hand, can be captured and evaluated by threshold comparisons, pattern recognition using neural networks, and other algorithms. The specific criterion also depends on the type of proximity sensor used, which, for example,It can be designed as a capacitive sensor (however, the method can also be used with other types of proximity sensors). Since this detection of actual operator events is state of the art, it will not be discussed further here.

[0013] Before a valid operation is actually recognized, a first operating signal is generated and output by the control and evaluation device, according to the invention. Completely different criteria can be used for this first operating signal than for the evaluation of the valid, complete operating event. It can, for example, be a subset of the criteria also used for the evaluation of the operating signal, or significantly broader criteria that are met for the correct execution of an operating event, although this may also include some invalid operating events. To generate the first operating signal, a timer t1 is started when the control and evaluation device detects the beginning of an actuation of the sensor device.The detection of an initiating action can be triggered, in particular, by a change in the proximity sensor readings beyond a certain deviation from the resting position. This could include, for example, crossing a threshold value that is at a predefined distance from the long-term average of the proximity sensor readings, or a percentage change compared to a moving average. When such a change in the readings is detected, the first timer t1 is started, and the acquisition of readings from the proximity sensors continues. If the first timer t1 reaches a first target value tz1, and the readings continuously meet a first criterion from the timer's start until the target value is reached, the first operating signal is generated at the signal output.The first criterion can be a complex one, or it can be a simple, continuous threshold comparison, such that if the measured values ​​fall back to the long-term average value in the unattended state, the criterion is not met. It can also be designed to check for a continuous monotonic decrease in the measured values ​​at the proximity sensor, whereby the measured values ​​can be subjected to smoothing or filtering beforehand. The first criterion can differ from the criteria used to detect valid operation in terms of data volume and type of criterion. Therefore, if the first criterion is designed to require minimal computational effort, early detection of the first criterion can be performed while simultaneously monitoring for completely correct operation.The runtime of the first timer t1 (i.e., the target value tz1) is selected within the scope of the invention such that this runtime is significantly shorter than the usual actuation duration. The target value tz1 is therefore reached in the usual actuation scenario before the actuation has been fully completed.

[0014] A downstream central control unit can further process the initial operating signal and use it as a trigger for a variety of processes, none of which yet include the final actuation. In particular, it is possible to provide information to the operator in response to the initial operating signal, informing them that an evaluation of the operating process is underway and that their current action is being assessed. Such feedback significantly improves user comfort, as the user does not have to wait until the final activation of the operating function to find out whether the vehicle or sensor device has entered an active and sensing state. Any signal perceptible to the user can be used for such notification, for example, activation of warning systems on the vehicle or other vehicle equipment (e.g., interior lighting).

[0015] The acquisition of measured values ​​continues even after the generation of the first operating signal. This continuation of measurement data acquisition proceeds according to the criteria used for the standard recognition of the operating gesture. Such recognition processes also typically have maximum durations after which they are aborted. If, during the continued acquisition of measured values, the second criterion—designed for recognizing a valid execution of an operating gesture—is met, and thus valid operation by the control and evaluation unit is established, then the second operating signal, following the first, is output at the signal output of the control and evaluation unit.

[0016] According to the invention, the system first checks whether a first operating signal has actually been generated. This ensures that whenever a second operating signal is generated, it is always preceded by a first operating signal. This guarantees a consistent user experience, meaning that an operation is never detected without the first operating signal having been generated. Such a check is necessary because, as mentioned above, the criteria for generating the first operating signal can differ from the criteria for recognizing successful operation. The first operating signal is generated based on an early evaluation, so it is entirely possible that the subsequent evaluation reveals that a valid operation did indeed occur, while the early evaluation had not met the first criterion for generating the operating signal.If the first criterion is, for example, a simple threshold comparison that checks whether the measured values ​​remain consistently above or below a predefined threshold during the first timer's runtime, a single deviation can cause this criterion to fail validation. For instance, if a zero value is delivered for any reason during signal transmission, the first criterion might be considered unfulfilled. The more complex evaluation, which may employ smoothing and filtering, used to generate the second control signal for a correctly executed, complete operation, could eliminate such errors and confirm that a valid operation has indeed occurred. Then, even though the first criterion was not met up to time tz1, the first control signal is subsequently generated and output, followed by the second control signal.This ensures that a second control signal is only issued after a first control signal has been received. Therefore, if the central control unit triggers a technical response to the first control signal, it can always be relied upon that this action will be executed before any actual user interaction.

[0017] According to the invention, the first and second control signals differ so that the downstream central control unit, which receives the signals from the control and evaluation device, can distinguish between the control signals at any time. The distinction can be based on any difference in signal encoding, frequency, signal level, or similar characteristics.

[0018] It is particularly preferred if the first and second control signals differ in their signal length.

[0019] Length encoding of the signals enables a particularly simple and reliable transmission in a vehicle's signaling system, for example via a bus system.

[0020] In a preferred embodiment of the invention, the first criterion includes a condition that the measured values ​​do not cross a predetermined first threshold.

[0021] This criterion checks whether a threshold value is crossed within the runtime of the first timer t1. For example, the initial rise or fall of the measured values ​​above or below a threshold value can be used as the criterion to start timer t1, thus triggering the detection of the initiating operating event. Afterward, until the first timer t1 expires, it is checked whether the signal falls or rises again toward the initial level. If this is not the case, meaning the signal has not crossed the threshold value again within the specified time period, the first operating signal is generated, possibly after checking for the fulfillment of further conditions. The advantage of such a simple threshold check lies in the low computational requirements for the evaluations and calculations.To keep such a system as simple as possible, low computing power requirements are advantageous, especially since the actual subsequent detection of an operator event may require all available resources for rapid evaluation. Furthermore, it has been shown that a simple threshold comparison can correctly detect the vast majority of operator events, with the threshold being determined empirically and depending on the vehicle model.

[0022] In a preferred embodiment of the invention, the sensor device comprises at least two proximity sensors, each providing measured values, and both of which are used for evaluation to generate the first control signal. Thus, until the first timer t1 reaches the target value, the sensor values ​​of both proximity sensors are used, allowing for a more precise and reliable early evaluation to generate the first control signal. For example, both sets of measured values ​​can be subjected to a threshold comparison, with each proximity sensor being assigned a specific threshold for comparison. In conventional sensor devices, such as those used in the rear of a vehicle, several proximity sensors, usually in the form of capacitive proximity sensors, are located at various positions on the vehicle's exterior.For example, a first proximity sensor is located in the bumper, while a second proximity sensor is positioned below it and further towards the center of the vehicle. If a pivoting motion of the foot is performed in this area, both proximity sensors detect a change in the signal, albeit with a time delay due to their position. As a first criterion, simple value comparisons can then be used for the two proximity sensors. However, the temporal progression of the measured values ​​of the proximity sensors can also be examined, for example, whether both proximity sensors show an increasing or decreasing trend until the first target value is reached by timer t1.

[0023] In a preferred embodiment of the invention, timer t1 is not only used for generating the first operating signal, but is also continuously monitored thereafter. It can then be provided that the timer t1 reaching a second target value TZ2 serves as a time limit for recognizing a valid operating event. Thus, if the control and evaluation unit does not recognize that a valid operating event has occurred by the complete execution of a correct operating gesture before the second target value TZ2 is reached, the operating event is discarded. In this way, a consistent maximum duration for possible operation is defined, which is clear and comprehensible to the user.

[0024] It is advantageous if the control and evaluation unit is operated in such a way that the signals output at the signal output are transmitted with a minimum time interval TD. The control and evaluation unit then ensures that even when several signals are to be output simultaneously or in quick succession, a minimum delay is maintained to guarantee error-free signal transmission within the vehicle system at all times. This is particularly relevant when the first and second operating signals are generated largely simultaneously. As described above, the first operating signal is always sent later if an operation is detected and the first operating signal had not yet been output. In this case as well, a delay in the operation of the control and evaluation unit ensures that the minimum time interval between the first and second operating signals is maintained.

[0025] According to the invention, if a first control signal has been issued, but no fully successful actuation has been detected and consequently no second control signal has been generated because the measured values ​​do not meet the second criterion, a fault actuation signal is issued, which differs from the first control signal and the second control signal.

[0026] The incorrect operation signal is therefore always issued when an initial operating signal has been sent, but no successful operation has subsequently been detected. This ensures that any effect triggered by the initial operating signal on the vehicle, or subsequently on the operator, is canceled out, resulting in a consistent operating sequence and user experience at all times. For example, if the initial operating signal is used to indicate to the operator that operator detection is in progress, the incorrect operation signal can be used to inform the operator of a corresponding unsuccessful detection attempt. This increases operator acceptance, as they can always track whether an operation is being detected, whether it was successful, or whether it was not successfully detected.

[0027] It is particularly advantageous if the initial operating signal is used to inform the operator of the ongoing evaluation process via acoustic or visual signals. The purpose of this procedure is to provide transparent operator guidance, as such visual or acoustic feedback keeps the user informed about the current status of the process at all times.

[0028] In a modified version of the procedure, in addition to or as an alternative to an optical or acoustic signaling signal, the first operating signal can be used as a trigger to initiate wireless radio communication for authorization querying of an ID transmitter carried by the operator.

[0029] Since the first control signal precedes the second control signal indicating successful opening, this time saving can be used to initiate a wireless query of an ID transmitter, which is necessary anyway before a vehicle function, especially a door opening, can be triggered. Using the first control signal for this purpose results in a more pleasant user experience and improved user acceptance.

[0030] The invention is explained in more detail below with reference to the accompanying drawing. Figure 1a shows the rear view of a vehicle for carrying out the method according to the invention; Figure 1b shows a schematic side view of the vehicle Figure 1a ; Figure 2 shows a flowchart of an embodiment of the method according to the invention.

[0031] In the Figures 1a and 1bFigure 1 shows a vehicle in which proximity sensor electrodes 2 and 3 are arranged in the rear area. These proximity sensor electrodes are connected to a control and evaluation unit 4, which controls the proximity sensor electrodes as capacitive electrodes and determines their respective capacitance. This control unit 4 is in turn coupled to a central control unit 5 of the vehicle. The control and evaluation unit 4 handles the control of the electrodes 2 and 3 and the signal evaluation, i.e., the determination of the signal responses and their assignment to a control signal. Any control signal generated is transmitted by the control and evaluation unit 4 to the central control unit 5, which can execute the closing function of the tailgate and the electric opening.

[0032] Electrode 2 is located in the lower rear area and its detection area 2a is directed downwards, as shown in Figure 1bshown. Electrode 3 is arranged such that its detection area 3a is directed to the rear.

[0033] In Figure 1bThe leg 6a, 6b of a user is shown in two different positions. In position 6a, the user is standing behind the rear of the vehicle, and the user's leg may be detected by sensor arrangement 3 with detection range 3a, but not by sensor arrangement 2 with its detection range 2a. However, if the user moves close to the tailgate and places their foot within detection range 2a, as shown in position 6b, detection in both range 3a and range 2a is possible. For successful user detection, both sensor 2 and sensor 3 must provide time-based signal sequences that conform to a criterion stored in the control and evaluation unit 4.This can take into account, for example, how long the user's leg must remain in position 6b to register a successful activation and how the measured values ​​of sensor 2 and sensor 3 change over time. How such a detection process works and how a corresponding second operating signal is generated is described in detail in the prior art. The control and evaluation unit can, in particular, perform pattern or threshold comparisons or even include a neural network to distinguish the actual operation from interference signals caused by other objects or environmental conditions.

[0034] According to the invention, however, the second operating signal, which signals successful activation to the central control unit 5, is preceded by a first operating signal. To generate the first operating signal, a timer t1 is started upon detection of initiating operation. In the present example, this timer can be started as soon as the proximity sensor electrode 3 and the proximity sensor electrode 2 detect the approach of an object, which is manifested by the increase of the measured values ​​above their respective assigned threshold values.

[0035] While the Figures 1a and 1b To illustrate the system that can be used to carry out the method according to the invention, the following is shown. Figure 2 the flow diagram of the method according to the invention in a first embodiment.

[0036] In a first section of the inventive method, which is described in Figure 2As shown in block 10, the control and evaluation unit 4 monitors the signals S1 and S2, each assigned to one of the proximity sensor electrodes 2 and 3, respectively. This monitoring is performed in a loop until the measured values ​​of both proximity sensor electrodes 2 and 3 cross a threshold value THR1 or THR2, respectively. Such a crossing of the aforementioned threshold values ​​indicates that an operator event may be beginning or initiating. The capacitance detected by the proximity sensor electrodes 2 and 3 changes so significantly compared to the previous state (a resting state or moving average) that the proximity of a user can be assumed. If this condition is met, i.e., if the assigned threshold values ​​THR1 or THR2 have been crossed at both proximity sensor electrodes 2 and 3, then process block 30 is executed.

[0037] Procedure block 30 describes how the first control signal is generated and the corresponding criteria in this embodiment of the invention. First, timer t1 is set to zero. Then, for a duration of timer t1, specifically as long as it is less than the target value tz1, it is checked whether signals S1 and S2, i.e., the measured values ​​of the proximity sensor electrodes 2 and 3, have not crossed the assigned threshold values ​​again and have risen or fallen towards their initial level. The reference here to falling and rising sensor values ​​is only relevant to this specific embodiment. Whether an approach is expressed by falling or rising measured values ​​depends on the type of signal representation and the circuitry of the proximity sensor electrodes.In process block 30, it is checked whether the signal data S1 and S2 remain on the same side of the assigned threshold values ​​for the duration of timer t1 and do not cross them again. If this is the case, a first operating signal is generated at the signal output of the control and evaluation unit. If this is not the case, the first operating signal is not generated. In any case, after the timer t1 has elapsed, the process returns to block 20. There, regardless of the previously or concurrently performed check in block 30, the measured values ​​S1 and S2 from the proximity sensors are used to check whether a valid operating event has occurred. The time required for this can be significantly longer than the duration tz1 and may therefore also take additional measured values ​​into account compared to the process in block 30.The evaluation of such a valid operating event can be performed using complex criteria and with significantly higher computational effort. For example, stored measured values ​​for a specific time range can be subjected to pattern matching or fed into a neural network. A variety of threshold comparison criteria can also be used to recognize a valid operating event. If a valid operating event is detected in block 20, it is checked whether an initial operating signal has been sent. If no valid operating signal was output in the previously or concurrently executed block 30, the initial operating signal is output first. Subsequently, the second operating signal, which indicates the recognition of the valid operating event, is output. The control and evaluation unit inserts a predefined minimum time interval between the first and second operating signals.

[0038] In this process, it is therefore always ensured that a second operating signal is always preceded by the first operating signal, even if it was not sent as part of the recognition in block 30.

[0039] However, if block 20 determines that no valid operating signal has been detected, the system first checks whether the first operating signal was generated in block 30. If not, the process is terminated and the measured values ​​S1 and S2 are monitored again. If, however, the first operating signal was sent in block 30, a fault signal is now issued by the control and evaluation unit. The system then returns to monitoring the sensors.

[0040] The reactions of the central control unit 5 to the first and second operating signals depend on the intended use and the specific vehicle manufacturer that has installed the system. As described above, a first operating signal can be used, in particular, to indicate to the user that their action is being continuously monitored. Alternatively, the first operating signal can be used to integrate a user-carrying authentication device, such as a key fob, into a radio communication system. In such a radio communication system, the vehicle can, for example, monitor the distance to a valid vehicle key while the actual user interaction is still in progress.Similarly, the incorrect activation signal can be used to send a corresponding message to the user or the accompanying means of authentication and, if necessary, to terminate a radio dialogue.

Claims

1. Method for evaluating a sensor device, wherein said sensor device includes at least one proximity sensor (2, 3) which captures the spatial proximity of bodies (6a, 6b), and wherein the sensor device includes at least one control and evaluation device (4) that is coupled to said proximity sensor and has a signal output, with the steps of repeated capturing the sensor measurement values of the proximity sensor (2, 3) with the control and evaluation device, if the sensor measurement values characterize an initiating operation of the sensor device, then - starting a first timer t1, - repeated capturing the sensor measurement values of the at least one proximity sensor (2, 3) with the control and evaluation device, - wherein when the first timer has reached a first target value tz1 and the sensor measurement values continuously fulfil a first criterion since the start of the first timer, a first operating signal is output at the signal output of the control and evaluation device (4), - continued capturing of the sensor measurement values of the at least one proximity sensor with the control and evaluation device (4), - when the sensor measurement values satisfy a second criterion configured designed to detect of a valid execution of an operating gesture, a valid operation is identified by the control and evaluation device (4), and • if a first operating signal has already been output, a second operating signal is output at the signal output, • if a first operating signal has not yet been output, the first operating signal is first output at the signal output of the control and evaluation device (4), and the second operating signal is then output at the signal output, - wherein the first and the second operating signal differ in terms of their characteristics, - wherein if the sensor measurement values do not fulfil the second criterion, an invalid operating signal is identified by the control and evaluation device, and if a first operating signal has already been output an incorrect operation signal is output at the signal output.

2. Method according to Claim 1, wherein the first and the second control signals differ in respect of their signal lengths.

3. Method according to Claim 1 or 2, wherein the first criterion includes a condition according to which the sensor measurement values do not cross a predetermined first threshold value.

4. Method according to any one of the preceding claims, wherein the sensor device includes at least two proximity sensors (2, 3), each of which supplies sensor measurement values, and when the first timer has reached the first target value and the sensor measurement values of all proximity sensors (2, 3) continuously fulfil a respectively assigned first criterion since the start of the first timer, a first operating signal is output at the signal output.

5. Method according to Claim 4, wherein the first criterion assigned respectively to each proximity sensor is a specific threshold value that the sensor measurement values of the respective proximity sensor (2, 3) must not cross.

6. Method according to any one of the preceding claims, wherein the second criterion contains a condition according to which a valid execution of an operating gesture must be detected within a running time of the timer tl and before the timer tl reaches a second target value tz2.

7. Method according to any one of the preceding claims, wherein the control and evaluation device delays the output of signals that are output at the signal output as necessary, in such a way that a minimum time interval td is maintained between each of the signals.

8. Method according to any one of the preceding claims, wherein the first operating signal and / or the incorrect operation signal is / are received with a processing unit and used as a trigger for actuating an optical or acoustic signalling device.

9. Method according to any one of the preceding claims, wherein the first operating signal is received with a processing unit and used as a trigger for actuating a wireless radio communication for authorisation query of an ID transmitter carried by the operator.