DE102019204058A1 - Force measuring device and method for determining a force exerted on a movable surface element of a vehicle component - Google Patents

Abstract

The approach presented here relates to a force measuring device (160) for determining a force (F) exerted on a movable surface element (140) of a vehicle component (130). The force measuring device (160) comprises a spring (230) which exerts a preload between the movable surface element (140) and a housing element (225) of the vehicle component (130). The force measuring device (160) further comprises a contactless measuring distance sensor (215) for detecting the distance (220) between the surface element (140) and the housing element (225). Finally, the force measuring device (160) comprises an evaluation unit (240), which is designed to measure the force (F) exerted on the surface element (140) using a parameter of the spring (230) and a distance measured by the distance sensor (215) ( 220) to be determined between the surface element (140) and the housing element (225).

Description

The present invention relates to a force measuring device and to a method for determining a force exerted on a movable surface element of a vehicle component according to the main claims.

In modern vehicles, vehicle components are often installed that are intended to be very easy and intuitive for a user to operate these vehicle components. Many of these vehicle components have a touch-sensitive user interface (touchscreen) in which an operator input is to be recorded using a force that is exerted on this user interface. In order to be able to measure this force as precisely and precisely as possible, sensors are required that have the lowest possible friction and thus cause little disruption of the force to be measured.

Against this background, the present invention creates an improved force measuring device and an improved method for determining a force exerted on a movable surface element of a vehicle component according to the main claims. Advantageous refinements result from the subclaims and the following description.

• eine Feder, die eine Vorspannung zwischen dem beweglichen Oberflächenelement und einem Gehäuseelement der Fahrzeugkomponente ausübt;
• einen berührungslos messenden Abstandsensor zur Erfassung des Abstands zwischen der Oberflächenelement und dem Gehäuseelement; und eine Auswerteeinheit, die ausgebildet ist, um die auf das Oberflächenelement ausgeübte Kraft unter Verwendung eines Parameter der Feder und einem von dem Abstandsensor gemessenen Abstand zwischen dem Oberflächenelement und dem Gehäuseelement zu ermitteln.

A force measuring device for determining a force exerted on a movable surface element of a vehicle component is presented, the force measuring device having the following features:

• a spring that applies a bias between the movable surface member and a housing member of the vehicle component;
• a contactless measuring distance sensor for detecting the distance between the surface element and the housing element; and an evaluation unit which is designed to determine the force exerted on the surface element using a parameter of the spring and a distance between the surface element and the housing element measured by the distance sensor.

In the present case, a surface element can be understood as a user interface element of such a vehicle component. The surface element can include further components such as a circuit board or components for evaluating signals or controlling further components of the vehicle, which are attached to the surface element or the circuit board, for example. The (operating) surface element can be movably connected with respect to a housing element arranged below the (operating) surface element. The housing element can be connected to other components of the vehicle in a fixed or rigid manner, so that a force exerted on the user interface element can move or displace the surface element in relation to the housing element. In the present case, a distance sensor can be understood to be a sensor which can detect a distance between the surface element (or a component connected to the (operating) surface element) and the housing element. Here, the distance sensor works without contact, for example via capacitive or inductive coupling or via optical detection or measurement of the distance between the surface element and the housing element. A spring constant can, for example, be understood as a parameter of the spring.

The approach presented here is based on the knowledge that with knowledge of the properties of the spring and the change in the distance between the movable surface element and the housing element, a conclusion can be drawn very easily and precisely about the force actually acting on the surface element. Due to the contactlessly detected distance between the surface element and in the housing element, the force acting on the surface element can also be determined very precisely and without interference, due to the avoidance of friction that occurs during a measurement.

An embodiment of the approach presented here is advantageous in which the distance sensor is designed as a capacitively measuring sensor and / or an inductively measuring sensor. Such an embodiment offers the advantage that the capacitive or inductive measuring principle delivers very precise results with regard to a distance measurement.

According to another embodiment of the approach proposed here, the distance sensor can be at least partially designed as a planar coil. Such an embodiment offers the advantage of being able to manufacture or provide the components required for the relevant measuring method in a technically very simple manner, so that a cost-effective and yet precisely measuring force measuring device can be created.

An embodiment of the approach proposed here is also conceivable in which the spring forms at least part of the distance sensor and / or in which the spring is at least partially metal. Such an embodiment offers the advantage of creating a possibility for a very large number of people compact and small design of the force measuring device, whereby an efficient use of material properties is made possible both for the function of the spring and for the function of the distance sensor.

According to a further embodiment of the approach presented here, the spring can be contacted in the area of the distance sensor on the housing element and / or at least part of the distance sensor can be formed between a contact area of the spring on the surface element and an edge of the surface element. Such an embodiment of the approach presented here offers the advantage of being able to exert the spring effect as close as possible in the area of the distance sensor, so that the smallest possible error when determining the force acting on the surface element using the distance between the surface element and the housing element measured with the distance sensor caused.

An embodiment of the approach presented here in which the spring is designed as a leaf spring can be carried out in a technically particularly simple and cost-effective manner.

An embodiment of the approach presented here is also particularly favorable in which the surface element is connected to a printed circuit board which comprises the evaluation unit and / or on which at least part of the distance sensor and / or the spring is arranged or formed. Such an embodiment offers the advantage of being able to arrange components required for the function of the force measuring device in a small installation space and / or in a technically very simple manner, without impairing the function of these components.

In order, for example, to also be able to give a user of a vehicle component haptic feedback about the detection of the force, an actuator can furthermore be provided according to a further embodiment of the approach presented here in order to actively move at least a partial area of the surface element. One or more different force pressure thresholds can also be implemented by such an actuator, so that information such as correct detection of the force exerted on the surface element can be signaled to the user of the vehicle component while the pressure is being exerted on the surface element.

According to a further embodiment of the approach proposed here, a second spring can furthermore be provided which exerts a pretension between the movable surface element and the housing element of the vehicle component. A second contactless measuring distance sensor can also be provided for detecting the distance between the surface element and the housing element, the evaluation unit being designed to measure the force exerted on the surface element using a parameter of the second spring and a second distance measured by the second distance sensor to determine the surface element and the housing element. Such an embodiment offers the advantage of being able to detect the distance between the surface element and the housing element at several different positions, so that, for example, a two-dimensional detection of the force on the surface element is possible. In this way, for example, a pattern or path in which the force is exerted on the surface element can also be recorded, for example the path over which a finger of a user of the vehicle component is guided over the surface element.

An embodiment is also particularly advantageous in which the actuator is arranged between the distance sensor and the second distance sensor and / or wherein the actuator is arranged between the spring and the second spring. Such an embodiment offers, on the one hand, a very compact design of the force measuring device and, on the other hand, a very precise possibility of measuring the force exerted on the surface element with the simultaneous possibility of operating the actuator, which then distributes an actively exerted force evenly between the distance sensor and the second distance sensor and thus minimizes or completely avoids any measurement errors that may occur.

The advantages of the approach presented here can also be achieved if, according to one embodiment, a method for determining a force exerted on a movable surface element of a vehicle component is implemented using a variant of a force measuring device presented here. The method according to this embodiment comprises a step of reading in a distance between the surface element and the housing element and a step of determining the force exerted on the surface element using the distance and a parameter of the spring.

According to a further embodiment of the approach presented here, an evaluation unit is presented which is designed to execute and / or control the steps of the method presented here in appropriate units.

Such an evaluation unit can be an electrical device that processes electrical signals, for example sensor signals, and outputs control signals as a function thereof. The Evaluation unit can have one or more suitable interfaces which can be designed in terms of hardware and / or software. In the case of a hardware design, the interfaces can, for example, be part of an integrated circuit in which the functions of the evaluation unit are implemented. The interfaces can also be separate, integrated circuits or at least partially consist of discrete components. In the case of a software design, the interfaces can be software modules that are present, for example, on a microcontroller alongside other software modules.

A computer program product with program code, which can be stored on a machine-readable carrier such as a semiconductor memory, a hard disk or an optical memory and is used to carry out the method according to one of the embodiments described above, is also advantageous if the program is on a computer or an evaluation unit is performed.

• 1 eine schematische Darstellung eines Fahrzeugs mit einer Kraftmessvorrichtung gemäß einem Ausführungsbeispiel;
• 2 eine schematische Querschnittsdarstellung durch einen Teil der Fahrzeugkomponente, die ein Ausführungsbeispiel einer Kraftmessvorrichtung aufweist;
• 3 ein Ablaufdiagramm eines Ausführungsbeispiels eines Verfahrens zur Ermittlung einer auf ein bewegliches Oberflächenelement einer Fahrzeugkomponente ausgeübten Kraft unter Verwendung einer Varianten einer hier vorgestellten Kraftmessvorrichtung; und
• 4 ein Blockschaltbild eines Ausführungsbeispiels einer Auswerteeinheit.

The invention is explained in more detail by way of example with reference to the accompanying drawings. Show it:

• 1 a schematic representation of a vehicle with a force measuring device according to an embodiment;
• 2 a schematic cross-sectional view through part of the vehicle component having an embodiment of a force measuring device;
• 3 a flowchart of an embodiment of a method for determining a force exerted on a movable surface element of a vehicle component using a variant of a force measuring device presented here; and
• 4th a block diagram of an embodiment of an evaluation unit.

In the following description of preferred exemplary embodiments of the present invention, identical or similar reference symbols are used for the elements shown in the various figures and having a similar effect, a repeated description of these elements being dispensed with.

1 shows a schematic representation of a vehicle 100 in which, for example, an engine 110 a drive power to a transmission 120 provides, from which in turn the drive power to wheels 125 of the vehicle is transmitted. In order to be able to select gear steps assigned to different driving speeds, in which the transmission 120 is to be switched, in the present case, for example, a gear selector switch as a vehicle component 130 provided over which a vehicle occupant 135 a gear selection or a gear ratio of the transmission 120 can choose. In modern vehicles, this is the vehicle component 130 designed such that to actuate the vehicle component 130 , here the selection of the specific gear selection stage, just a pressure or a movement with the finger on a (control) surface element 140 is to be exercised, with the vehicle component then from this pressure or movement 130 that of the vehicle occupant 135 manually entered gear selection and recognizes the transmission 120 by means of a control signal 142 controls accordingly.

However, it is also conceivable that the vehicle component shown here 130 is designed for the manual input of other control commands, for example to control an infotainment system 150 or similar. The function of the vehicle component is of particular relevance here 130 for a comfortable input of a control command by the vehicle occupant 135 . For this function of recording a force on the vehicle components 130 is now a force measuring device 160 provided, which is described in more detail below.

For this force measuring device 160 It should be ensured that the lowest possible friction when reading the force onto the user interface element 140 caused so by the vehicle component 130 very quickly appealing one from the vehicle occupant 135 on the on the user interface element 140 exerted force can be detected or also or a very small force is already detected precisely and clearly. In conventional systems, on the other hand, an approach to force detection is often used that in some cases involves a high level of force from the vehicle occupant 135 on the user interface element 140 Requires force to be exerted and thus for the vehicle occupant 135 has low comfort.

In order to be able to overcome the above-mentioned disadvantages of force detection subject to friction, an improvement of the vehicle component is required according to the approach proposed here 130 or a force measuring device 160 suggested.

2 shows a schematic cross-sectional illustration through part of the vehicle component 130 who have favourited the force measuring device 160 having. The control surface element 140 here comprises a substantially planar plate 200 , which is designed as a user interface and can be designed, for example, as a glass pane or plastic pane. On this record 200 for example, the one in the 1 depicted vehicle occupant 135 his finger 205 if you want to enter data. To now the pressure of the finger 205 on the user interface element 140 to be able to capture is on a rear side of the plate 200 , so one side that is not through the finger 205 touches a circuit board 210 arranged on which at least one distance sensor 215 is formed or attached. The distance sensor 215 is designed to be a distance 220 between the control surface element 140 or the circuit board 210 and a housing element 225 the vehicle component 130 to eat. For this purpose, for example, the housing element 225 the vehicle component 130 firmly with other components of the 1 illustrated vehicle 100 connected, whereas the user interface element 140 movable with respect to the housing element 225 is designed. By pressing your finger 205 on the plate 200 this is caused by a force F in the direction of the housing element 225 deflected, thereby increasing the distance 220 decreased.

There is also a spring 230 provided that the user interface element 140 with a previously known spring parameter (such as a spring constant) as far away as possible from the (fixed) housing element 225 presses so after a pressure of the finger 205 on the user interface element 140 this is brought back to its original position. On the circuit board 210 is now also an evaluation unit 240 arranged, which of the distance sensor 215 a the distance 220 representative signal 245 receives and using the spring parameter now determines the force F, which is caused by the finger 205 on the plate 200 was exercised. This determination can be made by utilizing the spring law known from physics, whereby a linear relationship between the spring force is favorable 230 exerted force F and a deflection distance of the spring 230 with known spring parameters, especially the spring constant, can be assumed. Thus the evaluation unit 240 with very simple technical means the force F can be determined, which is caused by the finger 205 on the plate 200 was exercised.

In order to address the disadvantages mentioned above in relation to the lack of comfort or the imprecise detection of the force F exerted by the finger 205 on the plate 200 of the control surface element 140 is exercised to avoid, a contactless measuring distance sensor 215 used. Such a contactless measuring distance sensor 215 can for example be based on an inductive and / or capacitive measuring principle; However, it is also the use of an optical measuring principle for the distance sensor 215 or another contactless measuring principle is conceivable. The distance sensor 215 can be formed, for example, by two opposing electrically conductive, for example metallic, layers, so that a capacitance is created between these layers when the distance changes 220 changes and thus vice versa this distance 220 can be detected or determined from this change in capacity. Alternatively or additionally, the distance sensor 215 a change in the inductance in the area around the distance sensor 215 detect, for example, if an electrically conductive or metallic element in the area of this distance sensor 215 moved or changed in its position. This way the distance can 220 can also be recorded very precisely. For the case of measuring a change in inductance, a part of the distance sensor can be used, for example 215 , for example on or on the circuit board 210 is arranged, be designed as a planar coil. A distance sensor designed in this way 215 can be produced in a technically very simple manner, for example in the same work step in which conductor tracks in the circuit board 210 be formed, for example, to guide the signal 245 be used.

The force measuring device 160 , which has been described in more detail above, can in this context at least as a combination of the features of the spring 230 , the distance sensor 215 and the evaluation unit 240 be understood.

The feather 230 can be of any shape. A very simple production or assembly can be achieved in that the spring 230 is designed as a leaf spring and between the housing element 225 and the circuit board 210 is introduced and thus the circuit board 210 from the housing element 225 pushes away. It is also particularly advantageous if one area of the spring 230 as part of the distance sensor 215 acts or is formed, for example if part of the spring 230 on the housing element 225 at a position opposite to the position of the distance sensor 215 lying on or on the circuit board 210 is upset. For example, is the pen 230 Manufactured from a metallic material or contains this metallic material, can thereby when the user interface element is pressed down 140 the approach of this part of the spring 230 to the distance sensor 215 be recorded capacitively or inductively, so that this very precisely to the current distance 220 can be closed.

Furthermore, according to the 2 illustrated embodiment an actuator 250 provided, for example, fixed to the housing element 225 connected and also to the circuit board 210 of the user interface element 240 can strike. The actuator can contain, for example, a motorized or magnetic element in order to, in addition to the spring 230 a (controllable) force F _A from the housing element 225 towards the circuit board 210 or the user interface element 140 exercise. In this way, for example, a haptic feedback can be given to the in the 1 illustrated vehicle occupants 135 , for example during this inmate 135 the finger 205 on the plate 200 presses to signal haptically that this pressure or the force F has been recognized. It is also conceivable that the 1 illustrated vehicle occupants 135 to transmit further information tactilely, for example which gear selection level is currently through the pressure of the finger 205 on the plate 200 is controlled.

According to the 2 illustrated embodiment of the force measuring device 160 is still a second distance sensor 215 ' provided a second distance 220 ' between the housing element 225 and the circuit board 210 of the control surface element 140 can recognize. The second distance sensor 215 ' can then send a second signal 245 ' to the evaluation unit 240 send whichever the second interval 220 ' corresponds. Furthermore, in the area of the second distance sensor 215 ' a second spring 230 ' be provided, which is also analogous to the spring 230 between the housing element 225 and the circuit board 210 is tensioned and a bias builds up, so that after a depression of the user interface unit 140 across the plate 200 the user interface unit 140 is transferred back to its original position. Here, part of the second spring can again 230 ' as the counterpart of the second distance sensor 215 ' serve, especially if the second sensor 215 ' also based again on a capacitive or inductive measuring principle, the second distance sensor 215 ' analogous to the distance sensor 215 can be constructed. However, it is also conceivable that the second distance sensor 215 ' based on an alternative measuring principle than the distance sensor 215 .

It is particularly advantageous if, according to the 2 illustrated embodiment of the distance sensor 215 and the second distance sensor 215 ' at opposite ends of the circuit board 210 are arranged. In particular, the actuator 250 at one position on the circuit board 210 attack that between the distance sensor 215 and the second distance sensor 215 ' lies. In this way, the most uniform possible distribution of the from the actuator 250 force exerted on the circuit board 210 cause the vehicle occupant to use his finger 205 A corresponding haptic information can be transmitted very pleasantly and comfortably, since there may be vibrations caused by the spring 230 and the second spring 230 ' can be dampened or balanced very efficiently. Thus, for example, the distance sensor 215 and the pen 230 mirror image of the actuator 250 to the second spring 230 ' and to the second distance sensor 215 ' on the housing element 225 or on the user interface element 140 be arranged.

It is also conceivable that the evaluation unit 240 not on the circuit board 210 is arranged, but in the area of the housing element 225 . In this case, however, there would be a signal from the distance sensor 215 or from the second distance sensor 215 ' from the movably mounted user interface element 140 to or through the housing element 225 to conduct, with such a movable line in principle subject to high wear. The one in the 2 configuration of the arrangement of the evaluation unit shown 240 on the circuit board 210 however, only a corresponding signal needs to be transmitted, which is then used to control the transmission, for example 120 through the signal 142 out 1 can be used. This signal from the evaluation unit 240 can, for example, also be transmitted wirelessly in order to be able to avoid the high wear and tear of a moving line as far as possible.

In summary, it can be stated that the force on the user interface element (or the user interface) that is applied to the user interface element or the user interface by a user or by the haptic feedback function should be measured in a contactless or smooth manner. This prevents the force measurement from introducing any additional disruptive forces into the system. The force measurement is helpful because the haptic feedback function can give the user haptic feedback of his input from a certain force on the user. With inductive displacement sensors or distance sensors, for example, distances from electrically conductive metals can be determined very well. Compared to other measuring systems, this measuring method has a relatively high resolution and accuracy. In addition, thanks to the inductive measuring method, the springs that are used to mount the user interface element can also be used as a measuring object for the inductive displacement sensor. Furthermore, the inductance required for the measurement can be implemented directly on an existing circuit board as a planar coil.

Since there is also a capacitive touch sensor system in the product, the path measurement of the user interface element can also be carried out as a capacitive path measurement. This has the advantage that the electronic components for evaluating the inductive displacement sensors could be omitted. With this approach, however, it should also be taken into account whether such a measurement is in conflict with other requirements for the product, such as functional safety, so that, if necessary, an alternative contactless distance measurement can be used.

3 shows a flow chart of an exemplary embodiment of a method 300 for determining a force exerted on a movable surface element of a vehicle component using a variant of a force measuring device presented here. The procedure 300 includes one step 310 reading in a distance between the surface element and the housing element. The method also includes 300 one step 320 determining the force exerted on the surface element using the distance and a parameter of the spring.

4th shows a block diagram of an embodiment of an evaluation unit 240 . The execution unit 240 shows an interface 410 for reading in a distance between the surface element and the housing element and a unit 420 for determining the force exerted on the surface element using the distance and a parameter of the spring.

The exemplary embodiments described and shown in the figures are selected only as examples. Different exemplary embodiments can be combined with one another completely or with regard to individual features. An exemplary embodiment can also be supplemented by features of a further exemplary embodiment.

Furthermore, method steps according to the invention can be repeated and carried out in a sequence other than that described.

If an exemplary embodiment comprises a “and / or” link between a first feature and a second feature, this can be read in such a way that the exemplary embodiment according to one embodiment has both the first feature and the second feature and according to a further embodiment either only the first Has feature or only the second feature.

List of reference symbols

100

vehicle

110

engine

120

transmission

125

bikes

130

Vehicle component

135

Vehicle occupant

140

User interface element, UI element

142

Control signal

150

Infotainment system

160

Force measuring device

200

plate

205

finger

210

Circuit board

215

Distance sensor

220

distance

225

Housing element

230

feather

240

Evaluation unit

245

signal

215 '

second distance sensor

220 '

second distance

230 '

second spring

245 '

second signal

300

Method for determining a force exerted on a movable surface element of a vehicle component

310

Reading step

320

Step of determining

410

Read-in interface

420

Unit for determining

Claims (14)

Force measuring device (160) for determining a force (F) exerted on a movable surface element (140) of a vehicle component (130), the force measuring device (160) having the following features: a spring (230) that exerts a bias between the movable surface element (140) and a housing element (225) of the vehicle component (130); a non-contact measuring distance sensor (215) for detecting the distance (220) between the surface element (140) and the housing element (225); and an evaluation unit (240) which is designed to measure the force (F) exerted on the surface element (140) using a parameter of the spring (230) and a distance (220) measured by the distance sensor (215) between the surface element ( 140) and the housing element (225). Force measuring device (160) according to Claim 1 , characterized in that the distance sensor (215) is designed as a capacitively measuring sensor and / or an inductively measuring sensor. Force measuring device (160) according to one of the preceding claims, characterized in that the distance sensor (215) is at least partially designed as a planar coil. Force measuring device (160) according to one of the preceding claims, characterized in that the spring (230) forms at least part of the distance sensor (215) and / or that the spring (230) is at least partially metal. Force measuring device (160) according to one of the preceding claims, characterized in that the spring (230) is contacted in the area of the distance sensor (215) on the housing element (225) and / or at least part of the distance sensor (215) between a contact area of the spring (230) is formed on the surface element (140) and an edge of the surface element (140). Force measuring device (160) according to one of the preceding claims, characterized in that the spring (230) is designed as a leaf spring (230). Force measuring device (160) according to one of the preceding claims, characterized in that the surface element (140) is connected to a printed circuit board (210) which comprises the evaluation unit (240) and / or on which at least part of the distance sensor (215) and / or the spring (230) is arranged. Force measuring device (160) according to one of the preceding claims, characterized in that an actuator (250) is also provided in order to actively move at least a partial area of the surface element (140). Force measuring device (160) according to one of the preceding claims, characterized in that a second spring (230 ') is also provided, which exerts a preload between the movable surface element (140) and the housing element (225) of the vehicle component (130) and a second Contactless measuring distance sensor (215 ') is provided for detecting a second distance (220') between the surface element (140) and the housing element (225), the evaluation unit (240) being designed to measure the force exerted on the surface element (140) (F) using a parameter of the second spring (230 ') and the second distance (220') between the surface element (140) and the housing element (225) measured by the second distance sensor (215 '). Force measuring device (160) according to Claim 8 and 9 wherein the actuator (250) is arranged between the distance sensor (215) and the second distance sensor (215 ') and / or wherein the actuator (250) is arranged between the spring (230) and the second spring (230'). Method (300) for determining a force (F) exerted on a movable surface element (140) of a vehicle component (130) using a force measuring device (160) according to one of Claims 1 to 10 wherein the method (300) comprises the following steps: reading in (310) a distance (220) between the surface element (140) and the housing element (225); and determining (320) the force (F) exerted on the surface element (140) using the distance (220) and a parameter of the spring (230). Evaluation unit (240) which is designed to carry out the steps of the method (300) according to Claim 11 to be executed and / or controlled in corresponding units (410, 420). Computer program which is set up to carry out the steps of the method (330) according to Claim 11 execute and / or control. Machine-readable storage medium on which the computer program is based Claim 13 is stored.

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