Device for a brake-by-wire system, pedal system, brake-by-wire system and method for a brake-by-wire system

Abstract

A device for a brake-by-wire system of a vehicle is proposed. The device comprises a distance sensor configured to: detect a distance traveled by a first target that can be coupled to a brake pedal of the vehicle; detect a distance traveled by a second target that can be coupled to the brake pedal; and a processing circuit configured to: determine a difference between the distance traveled by the first target and the distance traveled by the second target; determine a force acting on the brake pedal based on the difference; and generate a control signal for controlling a brake of the brake-by-wire system based on the force.

Description

Technical FieldThe present disclosure relates to brake-by-wire systems. Embodiments relate to an apparatus for a brake-by-wire system of a vehicle, a pedal system for a brake-by-wire system of a vehicle, a brake-by-wire system and a method for a brake-by-wire system of a vehicle.BackgroundBrake-by-wire systems conventionally measure the distance the brake pedal travels to actuate the brake. However, the actually intended braking force can therefore only be adjusted to a limited extent. Furthermore, conventional brake-by-wire systems cannot detect any mechanical blockages on the brake pedal. There is therefore a need for improved detection of the braking movement.The publication DE19841335A1 describes that an important aspect of a vehicle brake system which functions according to the brake-by-wire principle is the rapid and reliable detection of the braking request of the driver. The achievement of this task is critically dependent on the pedal sensor system assigned to the brake pedal with its measuring devices for detecting the values characterizing the actuation of the brake pedal. At least two measuring devices (4, 5) are provided for detecting the braking request of the driver. The measuring devices mentioned in this case each record the same characteristic values for the actuation of the brake pedal, for example the brake pedal force, the brake pedal travel or the brake pedal angle. To monitor the brake demand measuring devices (4, 5), these brake demand signals are compared with a signal of a third measuring device (6).The publication DE 10 2008 003 801 A1 describes that a control device for an electric brake system comprises: a first switching element which, when actuated, changes a first signal level present on a first signal line by a first level difference, a second switching element which, when actuated, changes a second signal level present on a second signal line by a second level difference which has a sign which is reversed with respect to the first level difference, an actuating element which actuates the first and the second switching element, a function activator which activates a function of the brake system if the first signal level changed by the first level difference or the second signal level changed by the second level difference is present on the first signal line, and a plausibility warning device which, based on the signal levels present on the first and the second signal line, outputs a plausibility warning signal. Furthermore, an electric brake system for a motor vehicle is provided, having such a control device and two brake circuits, wherein the first and second switching elements belong to different ones of the brake circuits. In a further aspect, a method for actuating an electric brake system is provided.The publication DE 10 2022 200 404 A relates to a method for operating a brake system in a vehicle, in which a brake unit for braking the vehicle is actuated as a function of a pedal travel of a brake pedal. The invention further relates to a computer program product and a brake system.The publication DE 10 2005 008 681 A1 relates to a driving dynamics operating element for a motor vehicle with communication of the desire specified by the driver electronically via sensors which determine both the path of the operating element initiated by the driver and the force applied to the operating element by the driver, wherein the determined sensor values are compared with one another in a control unit. At least two sensors are provided for determining the force applied by the driver and / or the path initiated by the driver, and the sensor values of the so-called force sensors and / or the so-called path sensors are each compared with one another for plausibility, wherein in the case of a significant deviation of the sensor values within the so-called group of path sensors or force sensors, a so-called substitute value is used as the sensor value of this sensor group, which substitute value is derived on the basis of the sensor value of the other group from a predefined value assignment between the sensor values of the force sensors and the path sensors. Different value assignments between the sensor values of the two groups are preferably provided for different boundary conditions, wherein the rate of change of the sensor value of the intact sensor group is a boundary condition for the selection of a value assignment.SummaryThis need is met by the technique described in the independent claims.One example is directed to an apparatus for a brake-by-wire system of a vehicle, comprising: a travel sensor configured to: sense a traveled distance of a first target couplable to a brake pedal of the vehicle; sense a traveled distance of a second target couplable to the brake pedal; and a processing circuit configured to: determine a difference between the travel distance travelled by the first target and the travel distance travelled by the second target; determine a force acting on the brake pedal based on the difference; and generate a control signal for activating a brake of the brake-by-wire system based on the force.Another example is directed to a pedal system for a brake-by-wire system of a vehicle, comprising: an apparatus according to the invention; the first target; and the second target.Another example is directed to a brake-by-wire system, comprising: a pedal system according to the invention; and the brake, wherein the brake is configured to apply a braking action to the vehicle based on the control signal.A further example relates to a method for a brake-by-wire system of a vehicle, comprising: by means of a travel sensor, detecting a travel distance of a first target couplable to a brake pedal of the vehicle; by means of the travel sensor, detecting a travel distance of a second target couplable to the brake pedal; and by means of a processing circuit, determining a difference between the travel distance travelled by the first target and the travel distance travelled by the second target; by means of the processing circuit, determining a force acting on the brake pedal based on the difference; and by means of the processing circuit, generating a control signal for actuating a brake of the brake-by-wire system based on the force.Brief Description of the FiguresSome examples of devices and / or methods are explained in more detail below with reference to the attached figures, merely by way of example. The following are shown: FIG. 1 shows an embodiment of a device for a brake-by-wire system; FIG. 2 shows an exemplary embodiment of a pedal system for a brake-by-wire system; FIG. 3 shows a further exemplary embodiment of a pedal system for a brake-by-wire system; FIGS. 4 aand 4 b show exemplary diagrams of an input signal and an output signal of a processing circuit of a device according to the invention; FIG. 5 shows an embodiment of a brake-by-wire system; and FIG. 6 shows a flow diagram of an exemplary embodiment of a method for a brake-by-wire system.DESCRIPTION OF THE INVENTIONSome examples will now be described in more detail with reference to the accompanying figures. However, other possible examples are not limited to the features of these embodiments described in detail. These may include modifications of the features, as well as equivalents and alternatives to the features. Further, the terminology used herein to describe certain examples is not intended to be limiting of other possible examples.The same or similar reference numerals refer to the same or similar elements or features throughout the description of the figures, which can each be implemented identically or in modified form, while providing the same or a similar function. In the figures, the thicknesses of lines, layers, and / or regions may be exaggerated for clarity.When two elements A and B are combined using one "or", it is to be understood that all possible combinations are disclosed, i.e., only A, only B, and A and B, unless expressly defined otherwise in the individual case. As an alternative formulation for the same combinations, "at least one of A and B" or "A and / or B" may be used. This applies equivalently to combinations of more than two elements.Where a singular form, e.g., "a," and "the," is used and the use of only a single element is not expressly or implicitly defined as obligatory, further examples may also use multiple elements to implement the same function. When a function is described below as being implemented using multiple elements, further examples may implement the same function using a single element or a single processing entity. It will be further understood that the terms "comprises," "comprising," "comprises," and / or "comprising," when used, describe the presence of stated features, integers, steps, operations, processes, elements, components, and / or a group thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, processes, elements, components, and / or a group thereof.FIG. 1 shows an exemplary embodiment of a device 100 for a brake-by-wire system of a vehicle. The brake-by-wire system is an electronic brake system of the vehicle that at least partially replaces mechanical connections between the brake pedal and the brakes. Instead of a physical brake booster or a hydraulic brake system, such a brake-by-wire system uses electronic signals to control the braking process. For this purpose, the brake pedal is detected by a sensor which detects the brake movement on the brake pedal exerted by the driver. This information is passed on, for example, to a control unit which controls the brake (e.g. brake calipers or brake blocks) on the wheels of the vehicle. The electronic control unit interprets the braking force signals and provides an appropriate braking effect on the individual wheels. This enables more precise and more individual control of the braking force, which is advantageous in particular in the case of vehicles having electronic stability control systems or other driver assistance systems.The device 100 can be integrated into the brake-by-wire system, for example, or external to the brake-by-wire system and be communicatively connected to the control device or the brake, for example, by wired or wireless signal transmission techniques.The apparatus 100 includes a displacement sensor 110 and a processing circuit 120 (e.g., a measurement IC; integrated circuit). The travel sensor 110 may be any sensor for detecting a travel distance, such as an incremental encoder or a linear travel sensor. An incremental encoder may generate pulses corresponding to changes in the position or movement of a target, i.e., they represent a relative displacement with respect to a reference point or a starting position. Such an incremental encoder can increase the resolution of the measurement.The displacement sensor 110 may be based on any physical principle, for example magnetic induction, Hall effect, optical sensing or capacitive measurement. The path sensor 110 outputs, for example, an output voltage or digital values representing the measured path.In some exemplary embodiments, the travel sensor 110 comprises an inductive sensor or is an inductive sensor. An inductive displacement sensor can measure a displacement or a position of a target using the inductive principle. The inductive displacement sensor comprises, for example, at least one coil which generates, for example, a high-frequency electromagnetic field. When a metallic target reaches the vicinity of the sensor, it changes the electromagnetic field in the coil and leads to a change in the inductance in the coil. This change in inductance is detected by the sensor and converted into a corresponding electrical signal. Such an inductive displacement sensor may be advantageous for a brake-by-wire application because of its robustness, accuracy and low reaction time.The processing circuit 120 may be, for example, a single dedicated processor, a single shared processor, or a plurality of single processors, some or all of which may be shared, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a microcontroller, or a field programmable gate array (FPGA). The processing circuit 120 may optionally be connected to read only memory (ROM) for storing software, random access memory (RAM), and / or nonvolatile memory.The displacement sensor 110 and the processing circuit 120 are communicatively coupled, i.e. the processing circuit 120 receives measurement values of the displacement sensor via a signal connection between the displacement sensor 110 and the processing circuit 120. The processing circuit 120 may, for example, tap an output voltage of the displacement sensor 110.The travel sensor 110 is designed to detect a travel covered by a first target that can be coupled to a brake pedal of the vehicle. The travel sensor 110 is furthermore designed to detect a travel covered by a second target that can be coupled to the brake pedal. The target may be any structure suitable as a position transducer. In the case of an inductive displacement sensor, the target can be, for example, a ferrite core or another at least partially metallic, magnetizable or magnetizable object.The first target and the second target can be coupled to the brake pedal in that they are to be mechanically connected thereto-i.e. their movement or position indicate a movement or position of the brake pedal. They are connected either directly or indirectly via a spring, for example, to the brake pedal. The first target can be coupled to the second target by a spring, for example. For example, the first target and the second target may be directly mechanically connected to different parts of the brake pedal, while these different parts are mechanically coupled to each other with a spring. The brake pedal may include, for example, a footrest coupled to the second target and a main body coupled to the first target, the main body and the footrest being coupled by a spring.The processing circuit 120 is configured to determine a difference between the distance travelled by the first target and the distance travelled by the second target and to determine a force acting on the brake pedal based on the difference. The processing circuit 120 is further configured to generate a control signal for activating a brake of the brake-by-wire system based on the force. The processing circuit 120 may, for example, pass the control signal to a controller of the brake or may itself control the brake to generate the braking action according to the calculated braking force on the brake pedal.The processing circuit 120 can obtain a respective position or a respective distance travelled by the two targets as a measurement signal from the distance sensor 110 or can itself determine on the basis of a measurement signal from the distance sensor 110. By calculating the difference between the two positions or paths, a force acting on a spring coupled between the two targets can be determined. This force is determined based on a known spring constant of this spring and indicates the force acting on the brake pedal, for example, it is proportional to the force acting on the brake pedal.Compared to conventional techniques, the apparatus 100 may allow to determine the actual braking force and not (only) the distance travelled by the brake pedal. This can improve the driveability and responsiveness of the brake of a brake-by-wire system. For example, different drivers may actuate the brake pedal at different intensities, resulting in different levels of braking force. By measuring the braking force, it can be ensured that a specific braking force is generated independently of the pedal distance. This ensures consistent braking behavior that takes account of a respective different use of the drivers. Moreover, the determination of the braking force may allow the performance of the brakes to be monitored and potential issues to be detected early. This contributes to safety in that possible defects or wear phenomena are detected and corrected before they lead to a failure of the brakes.Furthermore, the device 100 can also increase the safety of the brake-by-wire system for the following reasons: In the case of an unimpeded braking operation, the deflection (or deformation) of the spring or the difference in the paths can be small, since both targets move with the braking movement: the deflection of the spring is then determined by the counterpressure from the brake pedal main body. The spring could have a prestress, for example, so that it normally pushes away the first target with a small deflection. However, in the case of a mechanical blockage of the first target, a greater deflection of the spring and thus a higher difference in the paths would result. In the event of such a blockage, this path difference can then be used to further ensure the functionality of the brake-in that the braking force is derived from this difference. With conventional means, a blockage of a brake pedal can be detected only with difficulty or not at all, whereas this is possible with high precision with the device 100.Accordingly, the processing circuit 120 may be configured to detect a mechanical stall of the brake pedal based on the force. The detection of the blockage can be used, for example, to output a warning signal to the driver or else to change from a conventional brake control by means of pedal distance determination to that proposed here. A blockage of the brake pedal may have various causes, for example, a portion of the brake pedal, such as its spring mechanisms, may be damaged or blocked. This can result in the brake pedal no longer being freely movable and no longer being able to be pressed (completely). Blockage may also be caused by foreign bodies entering the area of the brake pedal. These foreign bodies may jam the pedal or otherwise impede its movement. The device 100 may be capable of detecting blockage by both rigid and elastic bodies.In some embodiments, the processing circuit 120 may be further configured to generate the control signal based on at least one of the traveled path of the first target and the traveled path of the second target. That is, in addition to the difference in the paths, the pedal distance itself may be used for controlling the brake. This can further increase the accuracy of the brake control.Alternatively, the last-mentioned measurement and control principle can be used as a default, wherein a change is made to a control by way of path difference only in the case of a detected blockage. As a result, the brake control can be simplified without having to dispense with the detection of blockages.In the case of an inductive sensor, the travel sensor 110 may include an excitation coil, a first periodic secondary coil pair configured to sense the travel of the first target, and a second periodic secondary coil pair configured to sense the travel of the second target. A respective coil pair can thus be provided in order to individually detect each of the targets, which increases the accuracy of the travel measurement.The periodic coil pairs can be, for example, so-called cosine and sine coils. The coils of a coil pair are then phase shifted with respect to one another by 90 degrees in their geometry. As a target moves through the magnetic field of a coil pair, the voltage generated by each coil of a coil pair is modulated according to the cosine of the angle between the magnetic field and the axis of the coil. By measuring the voltages on both coils, the position of the target can be calculated. The arctangent from the induced voltages can be determined to determine the angle by which the magnetic field has rotated relative to the coils and thus also the angle by which the target has moved relative to the coils.The excitation coil can be configured to generate an electromagnetic coupling with the first and the second secondary coil pair. It can improve the accuracy and sensitivity of the displacement measurement together with the secondary coil pairs. The excitation coil approximately generates a magnetic field that is crossed by the targets and generates an electrical signal that is detected by the secondary coil pairs. The use of excitation coils can thus amplify the magnetic field, which leads to a higher signal strength and thus contributes to an improved sensitivity of the displacement measurement. The use of excitation coils may also help reduce environmental disturbances that could interfere with the signal of the secondary coil pairs. By generating a constant magnetic field, external influences such as electromagnetic interference or magnetic materials in the environment can be insulated from the secondary coil pairs.The first and second secondary coil pairs may be commonly excited by only one exciting coil. For example, the excitation coil can encompass both secondary coil pairs. The use of a common exciting coil can save space, weight and cost. Further, control may be simplified: instead of controlling two separate coils independently of each other, a single control circuit may be used to control the common exciting coil.The first and the second secondary coil pair can furthermore be planar or flat. This can allow simple production, for example using printed circuit board technology. Furthermore, the secondary coil pairs can be more precisely aligned and spatially arranged relative to the targets by a planar geometry.In some exemplary embodiments, the device 100 comprises a printed circuit board, which in turn comprises the travel sensor 110. To adapt the travel sensor 110 to a curved pedal path, the printed circuit board can be designed at least partially in an arcuate manner. Thus, the distances of the displacement sensor 110 to the targets in a direction not to be measured can be kept constant in order not to falsify the measurements of the displacement along a direction to be measured.In order to achieve a high resolution of the force measurement, the number of periods of one of the secondary coil pairs can be increased. For example, the first or second secondary coil pair may have a higher winding density than the other of the first or second secondary coil pair. In some exemplary embodiments, the second secondary coil pair has a higher winding density than the first secondary coil pair. This has the advantage that the above-mentioned footrest is arranged at a small distance on the rest of the brake pedal and a spring length of the spring coupled therebetween can be kept short. In such a case, the resolution may nevertheless be large enough to determine the braking force sufficiently accurately. A small distance between the two brake pedal parts is advantageous in that the installation space of the brake pedal is not increased or is increased only insignificantly and blockage of the footrest relative to the rest of the brake pedal is also avoided.FIG. 2 shows an exemplary embodiment of a pedal system 200 for a brake-by-wire system of a vehicle. The pedal system 200 comprises a device 210 according to the invention, for example the device 100 described above.The device 210 comprises, as a travel sensor, an inductive sensor which comprises an excitation coil 212, a first periodic secondary coil pair 214 and a second secondary coil pair 216. The first periodic secondary coil pair 214 is configured to detect a distance travelled by a first target 230. The second periodic secondary coil pair 216 is configured to detect a distance travelled by a second target 240. The use of an inductive sensor in FIG. 2 is to be understood merely as an example. As described with reference to FIG. 1, the travel sensor may be any sensor for sensing a respective traveled distance of the first target 230 and the second target 240.In FIG. 2, the displacement sensor is formed planar on a printed circuit board. Furthermore, the second secondary coil pair 216 has a higher winding density than the first secondary coil pair 214. The first secondary coil pair 214 and the second secondary coil pair 216 are collectively disposed within the exciting coil pair 212. The geometry and arrangement of the coil pairs 214, 216 should be understood here as an example. In other exemplary embodiments, the inductive sensor can have, for example, only one secondary coil pair or two separate inductive sensors with a respective excitation coil and secondary coil. A further alternative would be a three-dimensional embodiment of the coils without a printed circuit board or a curved shape of the printed circuit board.The device 210 also comprises a processing circuit 220 which is designed to determine a difference between the distance travelled by the first target 230 and the distance travelled by the second target 240 and to determine a force acting on a brake pedal of the pedal system 200 on the basis of the difference. The processing circuit 220 is further configured to generate a control signal for activating a brake of the brake-by-wire system based on the force.The pedal system 200 further includes the first target 230 and the second target 240. In FIG. 2, the pedal system 200 also includes a first spring 250 configured to couple the first target 230 to a vehicle chassis (not shown) of the vehicle. As a result, a movement of the first target 230 indicates a travel of the pedal relative to the vehicle frame, which enables the determination of a desired braking effect on the basis of this travel.In FIG. 2, the pedal system 200 further includes a second spring 260 configured to couple the second target 240 to the first target 230. Such a spring 260 enables the determination of a desired braking effect on the basis of the path difference of the two targets 230, 240. It should be noted here that the springs 250, 260 do not necessarily have to be mechanical springs as in FIG. 2 : in other exemplary embodiments, the springs 250, 260 can also be elastic springs or gas springs.The second spring 260 has a mechanical bias in some embodiments. This has the result that, when the pedal is actuated in the normal case, the first target 230 is pressed away from the second target 240 without a large deflection of the second spring 260 occurring.In the event of a blockage of the first target 230, on the other hand, a greater deflection would occur, which can be used to continue operating the brake normally and / or to detect the blockage. In the event of a (e.g. elastic) blockage of the second target 240 with respect to the first target 230, on the other hand, an even smaller or no more deflection occurs-this can also be detected and does not influence the functionality of the brake.FIG. 3 shows a further exemplary embodiment of a pedal system 300 for a brake-by-wire system of a vehicle. The pedal system 300 comprises a device 310 according to the invention, for example a device 100 or 210 as described above. The pedal system 300 further includes the first target 330 and the second target 340.The pedal system 300 further includes a first spring 350 configured to couple the first target 330 to a vehicle chassis of the vehicle. In the example of FIG. 3, the spring 350 is fastened to a part 370 of the brake pedal, wherein the first part 370 is rigidly connected to the first target 330 via a connecting part 335.The pedal system 300 includes a second spring 360 configured to couple the second target 340 to the first target 330. In the example of FIG. 3, the spring 360 is fastened to a footrest 380 of the brake pedal, wherein the footrest 360 is rigidly connected to the second target 340 via a connecting part 345. The footrest 380 is coupled to the remainder 370 of the brake pedal and thus to the first target 330 by means of the second spring 360.The pedal system 300 further includes an optional pivot 390 on the vehicle chassis of the vehicle, wherein the brake pedal portion 370 is rotatably supported on the pivot 390.FIGS. 4 aand 4 b show exemplary diagrams 400 of an input signal 410, 420 and an output signal 430 of a processing circuit of a device according to the invention, such as the device 100 or 210. The input signals 410, 420 indicate the respective covered values of a first target and of a second target in millimeters (mm). The output signal 430 indicates the path difference of the two targets that results from the input signals 410, 420.In an unblocked state of a brake pedal, a relatively low travel difference results, as shown in FIG. 4 a. In a blocked state of the brake pedal, a higher path difference results, as shown in FIG. 4 b.On the basis of the output signal 430, the processing circuit can determine a force acting on the brake pedal and generate a control signal for actuating a brake of the brake-by-wire system on the basis of the force. This is also possible in the case of a mechanical blockage of the brake pedal, as shown in FIG. 4 b.FIG. 5 shows an embodiment of a brake-by-wire system 500. The brake-by-wire system 500 comprises a pedal system 510 according to the invention, for example the pedal system 200 or 300, and the brake 520. The brake 520 is configured to apply a braking action to the vehicle based on the control signal. For example, the brake 520 may be directly controlled via the processing circuit of the pedal system 510 or via a controller.For example, the information sensed by the sensors in the pedal system 510 may be converted to control signals and transmitted to the brake 520. The brake 520 may include one or more actuators that generate the mechanical motion to actuate the brakes based on the control signals (or based on the output signal of the processing circuit). In the brake-by-wire system 500, these may be electrical actuators, for example generating hydraulic forces in order to generate the braking action.FIG. 6 shows a flow diagram of an exemplary embodiment of a method 600 for a brake-by-wire system of a vehicle. The method 600 may be carried out, for example, by an apparatus according to the invention, for example apparatus 100.Method 600 includes detecting 610 a distance covered by a first target couplable to a brake pedal of the vehicle by means of a distance sensor, detecting 620 a distance covered by a second target couplable to the brake pedal by means of the distance sensor, and determining 630 a difference between the distance covered by the first target and the distance covered by the second target by means of a processing circuit. Method 600 further comprises determining 640 a force acting on the brake pedal based on the difference by means of the processing circuit and generating 650 a control signal for activating a brake of the brake-by-wire system based on the force by means of the processing circuit.Further details of the method 600 are described with reference to the apparatuses and systems with reference to FIGS. 1-5.The above-described devices and methods make it possible to determine the actual braking force and not (only) the distance traveled by the brake pedal. This can improve the driveability and responsiveness of the brake of a brake-by-wire system. Furthermore, the devices and methods can increase the safety of the brake-by-wire system by concluding from the deflection of a spring between the first target and the second target a mechanical blockage and, for example, changing an operating mode of the brake-by-wire system.Further exemplary embodiments of the proposed technique are described below:A first example relates to an apparatus for a brake-by-wire system of a vehicle, comprising a travel sensor configured to: detect a travel distance of a first target couplable to a brake pedal of the vehicle; detect a travel distance of a second target couplable to the brake pedal; and a processing circuit configured to: determine a difference between the travel distance travelled by the first target and the travel distance travelled by the second target; determine a force acting on the brake pedal based on the difference; and generate a control signal for activating a brake of the brake-by-wire system based on the force.A second example relates to an apparatus of any preceding example (such as the first example), wherein the processing circuitry is further configured to detect a mechanical blockage of the brake pedal based on the force.A third example relates to an apparatus of any preceding example (such as any of the first and second examples), wherein the displacement sensor comprises an incremental encoder.A fourth example relates to a device of any preceding example (such as any of the first through third examples), wherein the displacement sensor comprises an inductive sensor.A fifth example relates to an apparatus of any preceding example (such as the fourth example), wherein the inductive sensor comprises: an excitation coil; a first periodic secondary coil pair configured to sense the travel of the first target; and a second periodic secondary coil pair configured to sense the travel of the second target.A sixth example relates to an apparatus of any preceding example (such as the fifth example), wherein the first and second secondary coil pairs are planar.A seventh example relates to an apparatus of a preceding example (such as one of the fifth and sixth examples), wherein the excitation coil is configured to generate an electromagnetic coupling with the first and second secondary coil pairs.An eighth example relates to an apparatus of any preceding example (such as any one of the fifth to seventh examples), wherein one of the first and second secondary coil pairs has a higher winding density than the other of the first and second secondary coil pairs.A ninth example relates to an apparatus of any preceding example, further comprising a printed circuit board, wherein the printed circuit board comprises the displacement sensor.A tenth example relates to an apparatus of any preceding example (such as the ninth example), wherein the circuit board is at least partially arc-shaped.An eleventh example relates to an apparatus of any preceding example, wherein the processing circuit is further configured to generate the control signal based on at least one of the traveled distance of the first target and the traveled distance of the second target.A twelfth example relates to a pedal system for a brake-by-wire system of a vehicle, comprising: an apparatus of any of the preceding examples; the first target; and the second target.A thirteenth example relates to a pedal system of any preceding example (such as the twelfth example), further comprising a first spring configured to couple the first target to a vehicle body of the vehicle.A fourteenth example relates to a pedal system of any preceding example (such as any of the twelfth and thirteenth examples), further comprising a second spring configured to couple the second target to the first target.A fifteenth example relates to a pedal system of any preceding example (such as the fourteenth example), wherein the second spring has a mechanical pre-tension.A sixteenth example relates to a pedal system of any preceding example (such as any of the twelfth through fifteenth examples), further comprising the brake pedal, wherein the brake pedal has a foot rest coupled to the remainder of the brake pedal by a spring.A seventeenth example relates to a brake-by-wire system comprising a pedal system of any of the preceding examples and the brake, wherein the brake is configured to apply a braking effect to the vehicle based on the control signal.An eighteenth example relates to a method for a brake-by-wire system of a vehicle, comprising: by means of a travel sensor, detecting a travel distance of a first target couplable to a brake pedal of the vehicle; by means of the travel sensor, detecting a travel distance of a second target couplable to the brake pedal; and by means of a processing circuit, determining a difference between the travel distance travelled by the first target and the travel distance travelled by the second target; by means of the processing circuit, determining a force acting on the brake pedal based on the difference; and by means of the processing circuit, generating a control signal for actuating a brake of the brake-by-wire system based on the force.The aspects and features described in connection with a particular one of the preceding examples can also be combined with one or more of the further examples in order to replace an identical or similar feature of this further example or in order to additionally introduce the feature into the further example.Examples can furthermore be or relate to a (computer) program having a program code for executing one or more of the above methods when the program is executed on a computer, a processor or another programmable hardware component. Steps, operations, or processes of various of the methods described above may also be performed by programmed computers, processors, or other programmable hardware components. Examples may also cover program storage devices, e.g., digital data storage media, that are machine, processor, or computer readable and encode or contain machine-executable, processor-executable, or computer-executable programs and instructions. The program storage devices may include or be, for example, digital storage, magnetic storage media such as magnetic disks and magnetic tapes, hard disk drives, or optically readable digital data storage media. Further examples may also cover computers, processors, controllers, field programmable logic arrays ((F)PLAs=(field) programmable logic arrays), field programmable gate arrays ((F)PGA=(field) programmable gate arrays), graphics processors (GPU= Graph Processor Unit), application specific integrated circuits (ASIC=application-specific integrated circuit), integrated circuits (IC= Integr Circuit), or system-on-a-chip systems (SoC=System-on-a-chip) programmed to perform the steps of the methods described above.It is further understood that the disclosure of a plurality of steps, processes, operations or functions disclosed in the description or the claims should not be construed as necessarily in the described order, provided that this is not explicitly stated in the individual case or is absolutely necessary for technical reasons. Therefore, the foregoing description does not limit the execution of multiple steps or functions to a particular order. Further, in further examples, a single step, function, process, or operation may include and / or be broken into multiple substeps, functions, processes, or operations.Where some aspects have been described in the preceding paragraphs in the context of an apparatus or a system, these aspects should also be understood as a description of the corresponding method. In this case, for example, a block, a device or a functional aspect of the device or of the system can correspond to a feature, for example a method step, of the corresponding method. Accordingly, aspects described in connection with a method are also to be understood as a description of a corresponding block, a corresponding element, a property or a functional feature of a corresponding device or a corresponding system.The following claims are hereby incorporated into the Detailed Description, with each claim standing on its own as a separate example. It is further to be noted that although a dependent claim refers in the claims to a particular combination with one or more other claims, other examples may also comprise a combination of the dependent claim with the subject matter of any other dependent or independent claim. Such combinations are hereby explicitly proposed, unless it is stated in the individual case that a specific combination is not intended. Further, features of a claim are intended to be included for any other independent claim even if that claim is not defined directly as dependent on that other independent claim.

Claims

An apparatus (100; 210) for a brake-by-wire system of a vehicle, comprising: a travel sensor (110) configured to: detect a travel of a first target (230; 330) couplable to a brake pedal (370) of the vehicle; detect a travel of a second target (240; 340) couplable to the brake pedal (370); and a processing circuit (120) configured to: determine a difference between the travel travelled by the first target (230; 330) and the travel travelled by the second target (240; 340); determine a force acting on the brake pedal (370) based on the difference; and generate a control signal for controlling a brake of the brake-by-wire system based on the force.The apparatus (100; 210) of claim 1, wherein the processing circuit (120) is further configured to detect a mechanical blockage of the brake pedal (370) based on the force.The apparatus (100; 210) according to any one of the preceding claims, wherein the displacement sensor (110) comprises an incremental encoder.The apparatus (100; 210) of any preceding claim, wherein the displacement sensor (110) comprises an inductive sensor.The apparatus (100; 210) of claim 4, wherein the inductive sensor comprises: an excitation coil (212); a first periodic secondary coil pair (214) configured to sense the travel of the first target (230; 330); and a second periodic secondary coil pair (216) configured to sense the travel of the second target (240; 340).The apparatus (100; 210) of claim 5, wherein the first secondary coil pair (214) and the second secondary coil pair (216) are planar.The device (100; 210) according to any one of claims 5 or 6, wherein the excitation coil (212) is configured to generate an electromagnetic coupling with the first secondary coil pair (214) and the second secondary coil pair (216).The apparatus (100; 210) according to any one of claims 5 to 7, wherein the first secondary coil pair (214) or the second secondary coil pair (216) has a higher winding density than the other of the first secondary coil pair (214) or the second secondary coil pair (216).The apparatus (100; 210) of any preceding claim, further comprising a printed circuit board, wherein the printed circuit board comprises the displacement sensor (110).The apparatus (100; 210) of claim 9, wherein the circuit board is at least partially arcuate.The apparatus (100; 210) according to any of the preceding claims, wherein the processing circuit (120) is further configured to generate the control signal based on at least one of the traveled path of the first target (230; 330) and the traveled path of the second target (240; 340).A pedal system (200, 300, 510) for a brake-by-wire system of a vehicle, comprising: an apparatus (100; 210) according to any one of the preceding claims; the first target (230; 330); and the second target (240; 340).The pedal system (200, 300; 510) of claim 12, further comprising a first spring (250; 350) configured to couple the first target (230; 330) to a vehicle chassis of the vehicle.The pedal system (200; 300; 510) of any of claims 12 or 13, further comprising a second spring (260; 360) configured to couple the second target (240; 340) to the first target (230; 330).The pedal system (200; 300; 510) of claim 14, wherein the second spring (260; 360) has a mechanical bias.The pedal system (200; 300; 510) of any of claims 12 to 15, further comprising the brake pedal (370), wherein the brake pedal (370) has a foot rest coupled to the remainder of the brake pedal (370) by the second spring (260; 360).A brake-by-wire system (500) comprising: a pedal system (200; 300; 510) according to any one of claims 12 to 16; and the brake (520), wherein the brake (520) is configured to apply a braking action to the vehicle based on the control signal.A method (600) for a brake-by-wire system (500) of a vehicle, comprising: by means of a displacement sensor (110), detecting (610) a distance travelled by a first target (230; 330) couplable to a brake pedal (370) of the vehicle; by means of the displacement sensor, detecting (620) a distance travelled by a second target (240; 340) couplable to the brake pedal (370); and by means of a processing circuit (120), determining (630) a difference between the distance travelled by the first target (230; 330) and the distance travelled by the second target (240; 340); by means of the processing circuit (120), determining (640) a force acting on the brake pedal based on the difference; and by means of the processing circuit (120), generating (650) a control signal for controlling a brake of the brake-by-wire system (500) on the basis of the force.

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