System and method for determining changes in the mechanical vibration properties of a vehicle

Abstract

A system (1) is proposed, comprising - a vehicle (2), wherein the vehicle (2) is a two- or three-wheeled road vehicle, - an arrangement for determining changes in the mechanical vibration characteristics of the vehicle (2), wherein the arrangement comprises - a portable computing device (11) comprising at least one accelerometer, - a holding device (3) designed to hold the computing device (11) partially or completely on or in the vehicle (2), wherein the computing device (11) is configured to receive a mechanical vibration signal (S) of the vehicle (2) by means of the at least one acceleration sensor when the computing device (11) is partially or completely held by means of the holding device (3) during a journey of the vehicle (2), wherein the computing device (11) or the computing device (11) and an additional server (31) is / are configured to determine a frequency spectrum (F) from the vibration signal (S) and to determine a deviation (A1, A2, A3) of the frequency spectrum (F) from a reference frequency spectrum (RF). Furthermore, a corresponding procedure is proposed.

Description

[0001] The invention relates to a system comprising a vehicle and an arrangement for determining changes in the mechanical vibration properties of the vehicle, as well as a corresponding method.

[0002] Driving safety and comfort in road vehicles are closely linked to the condition of the vehicle's tires and rims, as well as its suspension and shock absorbers. This applies particularly to two-wheeled vehicles, such as bicycles, e-bikes, pedelecs, S-pedelecs, electric micro-vehicles (e.g., e-scooters), and motor scooters and other single-track vehicles, and also to three-wheeled vehicles (e.g., motorized tricycles).

[0003] Condition monitoring of two- and three-wheeled vehicles with regard to tires, rims, suspension, and shock absorbers is generally carried out reactively, i.e., after a defect has occurred, or at regular time or mileage intervals. Situations can arise where a vehicle is driven even though one of the aforementioned components is not functioning properly. Driving safety and / or ride comfort may be compromised.

[0004] Especially for operators of fleets of low-cost vehicles—such as rental companies and shared mobility providers—conventional inspections of tires, rims, suspension, shock absorbers, and potentially other parts and components are time-consuming and expensive. Furthermore, conventional inspections reduce the service life of a vehicle. Vehicles with defects that are detected too late can also develop consequential damage and incur significant subsequent costs. These disadvantages also apply to private users and other operators of vehicle fleets.

[0005] Especially with regard to two- and three-wheeled vehicles, which are relatively inexpensive to purchase, additional equipment with their own sensors would be costly and uneconomical.

[0006] From DE 10 2012 014 331 A1 a system is known, comprising: - a vehicle, wherein the vehicle is a two- or three-wheeled road vehicle, - an arrangement for determining changes in the mechanical properties of a roadway, wherein the arrangement comprises: - a portable computing device that has at least one accelerometer, - a holding device configured to partially or completely hold the computing device on or in the vehicle, wherein the computing device is configured to record a mechanical vibration signal of the vehicle using at least one acceleration sensor when the computing device is partially or completely held by the holding device during the vehicle's journey, wherein the computing device or the computing device and an additionally provided server is / are configured to determine a frequency spectrum from the vibration signal and to determine a deviation of the frequency spectrum from a reference frequency spectrum.

[0007] Methods for determining the vibration characteristics of vehicles in order to detect damage are known from DE 10 2023 108 765 A1, DE 10 2020 204 944 A1 and DE 10 2014 113 669 A1.

[0008] Holding devices on a handlebar are known from DE 20 2024 104 561 U1, DE 10 2020 200 659 A1 and DE 20 2009 002 544 U1.

[0009] The determination of a frequency spectrum using the Welch method is described, for example, in "Welch's method, In: Wikipedia, The Free Encyclopedia, Revision as of 6.1.2024, 16:32 UTC, URL: As described at https: / / en.wikipedia.org / w / index.php?title=Welch%27s_mehtod&oldid=1193983011.

[0010] The object of the present invention is to provide a cost-effective and simple means of enabling condition monitoring of two- and three-wheeled road vehicles during operation, particularly with regard to tires, rims, suspensions, dampers, and optionally additional parts and components that influence driving safety and comfort (e.g., axle components). The overarching goals are to maintain driving safety and comfort and to reduce operating costs.

[0011] The problem is solved according to the invention by a system with the features of claim 1 and a method with the features of claim 9. Advantageous embodiments are set forth in the dependent claims.

[0012] According to a fundamental concept of the invention, vibrations occurring in a vehicle during operation are detected using a portable computing device, which can be, in particular, a mobile device (e.g., a smartphone or tablet computer) or another end-user device with at least one accelerometer. The accelerometer can be part of an inertial measurement unit. The invention is based on the understanding that such an accelerometer, which is frequently installed in modern mobile devices and other end-user devices, can be used to detect mechanical vibrations (e.g., oscillations) in a vehicle that indicate a defect in the vehicle.

[0013] The computing device can also be used to analyze, by comparison with a reference frequency spectrum, whether mechanical vibrations are actually present that indicate a defect. A further insight is that this can particularly easily resolve the conflict of objectives between – especially inexpensive – two- and three-wheeled vehicles and relatively expensive sensors, since smartphones in particular are very widespread today.

[0014] In particular, a system is proposed that features - a vehicle, wherein the vehicle is a two- or three-wheeled road vehicle, - an arrangement for determining changes in the mechanical vibration characteristics of the vehicle, wherein the arrangement comprises - a portable computing device that has at least one accelerometer, - a holding device designed to partially or completely hold the computing device on or in the vehicle, wherein the computing device is designed to record a mechanical vibration signal of the vehicle using the at least one acceleration sensor when the computing device is partially or completely held by the holding device during a journey of the vehicle, wherein the computing device or the computing device and an additionally provided server is / are designed to determine a frequency spectrum from the vibration signal and to determine a deviation of the frequency spectrum from a reference frequency spectrum.

[0015] "At least one" is synonymous with "one or more." The terms "partly," "partially," or "at least partially" are each synonymous with "partially or entirely." Features are sometimes described in the singular below. Such a description may alternatively or additionally include a corresponding disclosure for several such features, if any, and vice versa.

[0016] The vehicle can, in principle, be any two- or three-wheeled road vehicle. Preferably, the vehicle is a bicycle, a kick scooter, a motor scooter, an electric micro-vehicle (especially an e-scooter), an e-bike, a pedelec, an S-pedelec, a trike, a motorized three-wheeled scooter, a motorized tricycle, or a non-motorized tricycle.

[0017] Due to the comparatively smaller number of safety-relevant and comfort-relevant components (especially compared to automobiles, passenger cars, and trucks), and the fact that sensors for monitoring these components are not usually provided, the invention is particularly suitable for vehicles that do not have their own monitoring sensors. Components on which a defect can be detected using a vibration signal measurement according to the invention are, in particular, tires, rims, suspensions, and shock absorbers. The vehicle can also be a motorcycle, especially a motorcycle without its own sensors for monitoring the aforementioned components.

[0018] The change in the mechanical vibration characteristics can, in particular, be a change compared to a new or defect-free condition of the vehicle.

[0019] Such a change can be caused, for example, by incorrect tire pressure, tire imbalance, wheel imbalance / bentness, a defective spring in the suspension, and / or a defective shock absorber. Further specific examples of causes for changes in mechanical vibration characteristics include: wheel bearing damage, wear of a control arm bushing, shock absorber aging, a broken spring, air loss in an air suspension system, a crack in a load-bearing component, or a change in the geometry / plastic deformation of a load-bearing component.

[0020] According to the invention, it is not necessary to perform or attempt a precise fault analysis with regard to a specific component based on the deviation, since the deviation of the frequency spectrum from the reference frequency spectrum already indicates a defect, which can subsequently be examined and localized more precisely by inspection and then remedied by targeted repair. The mere presence of the deviation is sufficient for this purpose.

[0021] The computing device can be, in particular, a mobile device. This refers to a mobile device that, due to its size and weight, can be carried without significant physical exertion and is therefore suitable for mobile use. The computing device can be, in particular, a mobile phone, a smartphone, a tablet computer, a smartwatch, or a fitness tracker. The computing device has at least one accelerometer. At least one additional accelerometer, which can, in particular, measure accelerations in another direction, and / or at least one gyroscope can be provided. Preferably, the computing device can have an inertial measurement unit (often called an "IMU").

[0022] The mounting device can be designed to be rigid. Generally, the mounting device can be designed to hold the computing device partially or completely stationary and rigidly relative to the vehicle. The mounting device can also be designed to fix the computing device partially or completely detachably to the vehicle. The mounting device can be provided, in particular, on a handlebar, steering column, or frame. Especially in the case of electric micro-vehicles, scooters, and bicycles, a mount on the handlebar or steering column designed for smartphones is common.

[0023] The holding device can be, in particular, a plug-in device and / or a clamping device. It can be designed to provide a positive locking and / or force-locking fix. It is advantageous if the holding device is designed in such a way that it enables rigid vibration transmission to the computing unit and thus the transmission of mechanical oscillations and vibrations. If the computing unit is designed to consist of several units (e.g., a fitness tracker with a wirelessly connected smartphone), the holding device can be designed to hold the unit in which the at least one accelerometer is provided.

[0024] The computing device can be configured to record, determine, and / or convert the mechanical vibration signal—before the frequency spectrum is determined—in such a way that vertical vibrations (which can be particularly informative with regard to potential defects in a tire, rim, suspension, damper, and possibly other axle components) are primarily or exclusively considered. Conversion can be performed, for example, using suitable axle rotations, e.g., from triaxial acceleration values. The term "recording" can include conversion, in particular the conversion of various sensor signals to vertical vibrations. The vibration signal can refer to vertical vibrations.

[0025] The mechanical vibration signal can be, in particular, a sequence of acceleration values ​​in the time domain. It can be recorded, for example, at a sampling frequency of 100 Hz. Specifically, it can represent vibrations occurring on the vehicle in the area of ​​the mounting device. The vibration signal can be recorded, for example, at a predefined time interval and / or during a journey over a predefined route.

[0026] The mechanical vibration signal can consist, in particular, of dynamic vehicle reactions to the dynamic forces occurring at the wheel-road contact point during driving. These dynamic vehicle reactions can be described by a linear, time-invariant system. With such a system, a response in the form of an output signal to any input signal can be calculated using the system's impulse response (usually denoted as g(t)). Measured acceleration values ​​(the mechanical vibration signal) can serve as the output signal. The impulse response can characterize the system, which might consist of, for example, tires, rims, suspension, and dampers, with respect to its suspension / damping behavior.

[0027] Determining the frequency spectrum from the vibration signal can be achieved, in particular, by means of a Fourier transform. The frequency spectrum can, in particular, correspond to the Fourier transform of the impulse response. The frequency spectrum can, in particular, be a spectral power spectral density.

[0028] The frequency spectrum can be the frequency spectrum of the oscillation signal, or it can include the oscillation signal and other oscillation signals, for example, signals recorded over longer distances and / or time periods. The frequency spectrum can also be a power spectral density determined using the Welch method (including: splitting an original signal into overlapping signal segments, applying time-domain window functions to the signal segments, calculating the frequency spectrum using the discrete Fourier transform, calculating the quadratic amplitude of the frequency spectrum, and averaging the individual spectra).

[0029] The deviation of the frequency spectrum from the reference frequency spectrum can include at least one quantitative specification relating to at least one frequency. The deviation can be at least a difference between a value of the frequency spectrum and a value of the reference frequency spectrum at a specific frequency.

[0030] The deviation of the frequency spectrum can consist of several pairs of values ​​of the frequency and the corresponding difference. The deviation of the frequency spectrum can be the mean square deviation of the frequency spectrum and the reference frequency spectrum, or their square root.

[0031] The reference frequency spectrum can correspond to the behavior of the vehicle in a new or defect-free condition. It can, for example, have been previously recorded using the vehicle itself, using a vehicle of the same type, or by averaging several frequency spectra of several vehicles of the same type in a new or defect-free condition.

[0032] The computing device can be configured to assess the deviation, particularly using a predefined criterion. The computing device can also be configured to output the result of this assessment.

[0033] The computing device can be configured to determine the frequency spectrum and its deviation. For this purpose, the computing device can have appropriate software (for example, a corresponding app).

[0034] Alternatively, a server can be provided, and the computing equipment and the server can be configured to determine the frequency spectrum and the deviation. This could mean, for example, - that the computing device is designed to determine the frequency spectrum and send it to the server, and the server is designed to determine the deviation, or - that the server is designed to determine the frequency spectrum and send it to the computing device, and the computing device is designed to determine the deviation, or - that the computing device is designed to send the vibration signal to the server and the server is designed to determine the frequency spectrum and the deviation.

[0035] The computing equipment and the server can be configured to jointly determine the frequency spectrum and / or the deviation in any division of labor.

[0036] Appropriate software (e.g., an app) can be installed on the computer and similar software can be installed on the server. The computer and the server can be configured to exchange data wirelessly (e.g., via a mobile network connection such as LTE or 5G). Both the computer and the server can each have a transmitting / receiving device.

[0037] The computing device can be configured to output a signal when the deviation is determined. The signal can contain information that is tailored to the deviation, e.g., a warning message.

[0038] Alternatively or additionally, the vehicle can have its own transmitter / receiver and receive an instruction from the server to issue a signal or perform an action when a deviation is detected. The signal can contain information that is tailored to the deviation, such as a warning message. Alternatively or additionally, the signal can be the illumination of a warning light or the sound of a warning tone on the vehicle. The action can be, for example, reducing or switching off the vehicle's engine and / or applying the brakes, or—more generally—preventing further travel of the vehicle.

[0039] The described system is advantageous because it provides a cost-effective and simple way to monitor the condition of two- and three-wheeled road vehicles, especially inexpensive vehicles, and particularly with regard to tires, rims, suspensions, shock absorbers, and potentially additional parts and components that affect driving safety and comfort (e.g., axle components). Such road vehicles typically do not have their own suitable sensors. They are generally relatively inexpensive vehicles for which the use of dedicated sensors would be uneconomical. The vast majority of users of such road vehicles today possess a mobile device, especially a smartphone, making the implementation of the invention cost-effective and possible without the need for additional hardware.Furthermore, the invention is very easy to implement in practical use and can be done simply by inserting the mobile device into the holding device and, if necessary, starting a corresponding app.

[0040] If a vehicle has a defect that could impair driving safety and comfort, it can be immediately taken out of service and / or undergo prompt maintenance or repair. This reduces or eliminates risks to the driver, passengers, and potentially other road users. The vehicle's roadworthiness can be quickly restored and thus maintained. Unnecessary inspections and costly consequential damage are avoided, thereby reducing the vehicle's operating costs.

[0041] The server, if provided, or any additional server that is planned, is configured as follows: - Evaluations of deviations in terms of frequency and amount with regard to specific vehicles, vehicle types or vehicle fleets and / or - To make comparisons of deviations in terms of frequency and amount between different vehicles, vehicle types or vehicle fleets.

[0042] The evaluations can be, in particular, statistical evaluations.

[0043] The presented design also allows for the investigation of the reliability of specific vehicles, vehicle types, and vehicle fleets. This enables the identification of vulnerable or particularly reliable vehicles, vehicle types, or vehicle fleets. By selecting particularly reliable vehicles, vehicle types, or vehicle fleets in the future and avoiding vulnerable ones, economic advantages (cost savings, savings on repair and maintenance work) and safety benefits for users can be achieved.

[0044] The following are not related to the invention and are disclosed here: - the use of the presented system / method mutatis mutandis for rail vehicles and other non-road vehicles, - the use of the presented system / method mutatis mutandis for aircraft, in particular airplanes and helicopters, here with regard to vibrations that occur during operation in the air and possibly during taxiing on the ground, - the use of the presented system / method mutatis mutandis in the event that the computing device is not on the vehicle, but worn on the body of a driver or a passenger of the vehicle, - the use of the presented system / method mutatis mutandis not for mechanical vibrations, but for sound signals which are recorded using a microphone of the computing device, whereby an acoustic frequency spectrum is created and a comparison with an acoustic reference frequency spectrum is carried out and in case of deviations a safety-relevant and / or comfort-relevant defect is concluded.

[0045] Furthermore, the following is disclosed at this point - also not pertaining to the invention: The presented system / method may also be suitable, mutatis mutandis, for four-wheeled vehicles, particularly automobiles (especially cars and trucks) and vehicles that are equipped with their own sensors (e.g., tire pressure sensors, shock absorber sensors) for monitoring safety-relevant and comfort-relevant components. It may also be suitable for quads, go-karts, and amusement ride vehicles. The described measurement of the vibration signal allows for the detection of component defects, especially those not monitored by the vehicle's own sensors. Furthermore, measurement results indicating a defect are not always displayed to the driver but are sometimes merely stored in an error memory. The presented system, however, allows measurement results indicating a defect to be displayed to the driver, e.g.,...in the form of a warning message.

[0046] In an advantageous embodiment of the system according to the invention, the reference frequency spectrum is determined using a previous journey or a plurality of previous journeys of the vehicle and / or at least one other vehicle of the same type as the vehicle.

[0047] The previous journey or journeys may have been carried out when the vehicle, or at least one other vehicle, was new or nearly new and / or free of defects. The reference frequency spectrum can therefore represent a defect-free target state.

[0048] In this embodiment, a condition monitoring system according to the invention is particularly reliable because a deviation from the reference frequency spectrum becomes apparent as early as possible, when the reference frequency spectrum corresponds to a defect-free target state that exactly matches the vehicle or vehicle type in a defect-free state. If a number of other vehicles of the same type form the basis, the informative value of the reference frequency spectrum and of deviations from it can be further increased.

[0049] In an advantageous embodiment of the system according to the invention, the previous journey or the majority of previous journeys have been carried out on a reference route and / or in a reference area.

[0050] The reference section and / or the reference area can be selected, in particular, based on a road surface located within the reference section and / or the reference area. For example, it could be a road surface known to produce vehicle vibrations when driven over, resulting in a particularly uniform frequency spectrum across different frequency ranges. Such a road surface could be, for example, cobblestones. Cobblestones can produce stronger and more significant vehicle vibrations than, for example, a largely flat asphalt surface.

[0051] The reference route can have a defined length and defined boundaries (in particular: start, end, lateral boundaries). The reference route can be, for example, a road, a path, a section of a road, or a section of a path. The reference area can have a defined extent and defined boundaries. For example, the reference route can be the exit of a yard where the vehicle and / or other vehicles of the same type are frequently located.

[0052] In this configuration, a condition monitoring system according to the invention can be particularly reliable because the reference section and / or the reference area can be specifically selected to obtain a particularly uniform and / or informative reference frequency spectrum across various frequency ranges. If a number of additional vehicles of the same type form the basis, the informative value of the reference frequency spectrum and of deviations from it can be further increased.

[0053] In an advantageous embodiment of the system according to the invention, the computing device is configured to record the mechanical vibration signal when the vehicle travels on the reference track and / or in the reference area and / or on a track whose surface corresponds to a surface of the reference track and / or a surface in the reference area.

[0054] The computing device may be equipped with or connected to a positioning system for this purpose. The positioning system may, in particular, be a receiver of signals from a navigation satellite system. The computing device may be configured to automatically begin recording the mechanical vibration signal when the vehicle begins traveling along the reference track and / or reference area and / or route, and to automatically end the recording when the travel along the track or reference area is completed or when the vehicle leaves the reference track or reference area or route. The computing device may receive information about the start and / or end of the recording from the server, if provided for.

[0055] The computing device and / or server may contain a database of floor coverings and their assignment to routes, areas, positions, or coordinates, or be configured to access such a database. The computing device and / or server may also contain a digital map, for example, in the form of an electronic city map, for implementing such assignments, or be configured to access such a map.

[0056] In this embodiment, a condition monitoring system according to the invention can be particularly reliable and informative, since the conditions under which the reference frequency spectrum was determined and the conditions under which the frequency spectrum is determined are similar. The probability that a deviation of the frequency spectrum from the reference frequency spectrum actually indicates a defect in the vehicle is particularly high.

[0057] In an advantageous embodiment of the system according to the invention, the computing device is designed to determine the frequency spectrum using the Welch method.

[0058] The Welch method includes in particular: splitting an original signal into overlapping signal segments and applying window functions in the time domain to the signal segments, calculating the frequency spectrum using the discrete Fourier transform, calculating the quadratic amplitude of the frequency spectrum, and averaging the individual spectra.

[0059] The Welch method can advantageously reduce noise in the vibration signal. This improves the informativeness of the frequency spectrum and thus the reliability of a condition monitoring system according to the invention.

[0060] The reference frequency spectrum can also be determined using the Welch method.

[0061] An advantageous embodiment of the system according to the invention is characterized in that the vehicle - has a handlebar and the mounting device is attached to the handlebar, - has a steering column and the holding device is attached to the steering column or - has a frame and the holding device is attached to the frame.

[0062] The handlebars, steering column, and frame are typically rigid or largely rigid, mostly metallic components that dampen vibrations only to a limited extent. Vibrations of a wheel, rim, suspension, shock absorber, and possibly other axle components, which can affect safety and comfort, are therefore particularly easy to detect at the handlebars, steering column, and frame. In this configuration, a condition monitoring system according to the invention can be exceptionally reliable and informative.

[0063] In an advantageous embodiment of the system according to the invention, - the computing equipment and / or - the server, if provided for, is designed to perform an assessment of the deviation using a predefined criterion.

[0064] For example, if the deviation with respect to one or more frequencies exceeds a predetermined amount or several (frequency-dependent) amounts, an assessment can be made in such a way that the criterion is either met or violated.

[0065] An assessment result, such as a warning message, can be output, for example, by an acoustic and / or visual signal to a user of the vehicle (for example, via a display and / or an audio output from the computer unit) and / or a message to a lessor and / or owner of the vehicle. Output can be made, for example, by the computer unit or by the server, if provided for, or by another server that can be connected to the computer unit and / or the server.

[0066] The consequence may be that the vehicle should be taken out of service and / or undergo an inspection and / or repair. Automatic decommissioning depending on the assessment result may be implemented.

[0067] The presented design is advantageous because it allows for a particularly rapid response to a vehicle malfunction. Driving the vehicle in a defective state, which could be detrimental to safety and / or comfort, is effectively and quickly avoided.

[0068] In an advantageous embodiment of the system according to the invention, the computing device and / or the server, if provided, is / are configured to display a message, in particular - a warning message, - a repair recommendation, - a safety notice and / or - to issue a decommissioning order with regard to the vehicle, depending on the assessment of the deviation.

[0069] The computing unit and / or server can be configured to issue different levels of messages and / or perform actions depending on the magnitude of the deviation. The predefined criterion can therefore be multi-level. For example, the computing unit and / or server can be configured to issue a warning message and / or a repair recommendation for a minor deviation that indicates a comfort issue but is not safety-relevant. Conversely, the computing unit and / or server can be configured to issue a safety warning and / or a shutdown command, which can lead to the immediate shutdown of the vehicle, for a major deviation that indicates a safety issue (examples of such issues that can lead to significant deviations include: a loss of tire pressure, a broken suspension, a malfunctioning shock absorber, or a wheel imbalance).

[0070] The presented design is advantageous because it allows for a particularly fast and precise response to a vehicle defect. Driving the vehicle in a defective state, which could be detrimental to safety and / or comfort, can be effectively and quickly avoided.

[0071] In an advantageous embodiment of the system according to the invention, the computing device and / or the server can be configured to record a temporal progression of the deviation and extrapolate it into the future in order to predict a time when an intervention threshold will be reached.

[0072] The proposed design is advantageous because it enables predictive maintenance of the vehicle. Downtime due to inspection and maintenance can thus be better planned and further reduced.

[0073] Furthermore, a method for determining changes in the mechanical vibration properties of a vehicle is proposed, comprising a system according to one of the preceding claims: - Providing a vehicle, wherein the vehicle is a two- or three-wheeled road vehicle, - Providing an arrangement comprising a portable computing device having at least one acceleration sensor and a holding device configured to hold the computing device partially or completely on or in the vehicle, wherein the computing device is designed to record a mechanical vibration signal of the vehicle using the at least one acceleration sensor when the computing device is partially or completely held by the holding device during a journey of the vehicle, - Holding the computing device using the holding device, - Carrying out the journey, - Determining a frequency spectrum from the oscillation signal and determining any deviation of the frequency spectrum from a reference frequency spectrum, either by the computing device or by the computing device and an additional server. The server, if present, or another server, performs the evaluations and / or comparisons.

[0074] The features of the embodiments of the system or process described above can be the subject of the process according to the invention. With regard to the process according to the invention, all embodiments of the system are fully incorporated by reference, and vice versa.

[0075] The invention is described below with reference to exemplary embodiments. The figures shown are: Fig. 1: a schematic view of a system according to the invention, Fig. 2: a schematic, simplified mechanical model of the in Fig. 1 system according to the invention as shown, Fig. 3: a portable computing device according to the invention, Fig. 4: a server according to the invention, Fig. 5: a vibration signal, Fig. 6: a frequency spectrum (power spectral density) and a reference frequency spectrum (reference power spectral density), with deviations existing.

[0076] Identical reference symbols used in different figures signify identical or essentially the same parts or features, even if not every figure refers again to all the features or parts shown with reference symbols.

[0077] Fig. Figure 1 shows a schematic view of a system 1 according to the invention. The system provides a vehicle 2, which is a bicycle. The vehicle 2 can also be, for example, an e-bike, a pedelec, or an S-pedelec. Alternatively, the vehicle 2 could be another two-wheeler or, with appropriate modifications, a tricycle. The vehicle 2 has a front wheel and a rear wheel. The front wheel has a front tire 4a and an assembly 5 consisting of a rim, spokes, and a hub. The rear wheel has a rear tire 4b and an assembly 5 consisting of a rim, spokes, and a hub. In the illustrated state, the vehicle 2 contacts a ground 15, which may have, for example, cobblestones (or other paving), with its front tire 4a in a front contact area 16a. The vehicle 2 contacts the ground 15 with its rear tire 4b in a rear contact area 16b.

[0078] The vehicle 2 has a front damper 6a and a front suspension 7a on the front axle. On the rear axle, the vehicle 2 has a rear damper 6b and a rear suspension 7b. The vehicle 2 also has a steering rod 8, a handlebar 9, and a frame 10. The steering rod 8 is rotatably mounted in a tube of the housing 10. A holding device 3, designed as a clamping device, is provided on the steering rod 8. It can be made of metal. A portable computing device 11, designed as a smartphone, is held by the holding device 3.

[0079] Furthermore, a Server 31 is planned (see also Fig. 4), which is located in a data center. Computing unit 11 and server 31 are designed to exchange data with each other. A mobile communication standard (for example, LTE or 5G) can be used for this purpose. Computing unit 11 has a transmit / receive unit 14 for this purpose (see Fig. 3, in which the computing device 11 is shown schematically).

[0080] The computing device 11 is designed to transmit a vibration signal S during travel on the ground 15 (cf. Fig. 5) to record the values ​​of the vertical acceleration [m / s²] 2 ], plotted against time [s], consists of a vertical oscillation signal. The computing device 11, as shown in Fig. Figure 3 shows an inertial measurement unit 13. The inertial measurement unit 13 has several accelerometers and several gyroscopes. Furthermore, the computing unit 11 has a processor 12, which functions as the central computing unit and is also configured using corresponding program instructions that may be stored in a memory (not shown) of the computing unit 11: • to calculate the vibration signal S (exhibiting vibration values ​​in the vertical direction) from values ​​measured by the acceleration sensors and • from the oscillation signal S a frequency spectrum F (see Fig. 6) to determine, if necessary using the Welch method, where the frequency spectrum F is a power spectral density spectrum.

[0081] The computing unit 11 is further configured to transmit the frequency spectrum F to the server 31 using the transmit / receive unit 14 to the server 31.

[0082] Server 31 has - see Fig. 4 - via a transmit / receive device 34 and a processor 32. The processor 32 is designed to compare the frequency spectrum F with a reference frequency spectrum RF using appropriate program instructions, which may be provided in a memory (not shown) of the server 31 (see Figure 4). Fig. 6). Fig. Figure 6 shows values ​​of the frequency spectrum F and the reference frequency spectrum RF as values ​​of the spectral power density [dB / Hz] versus the frequency [Hz].

[0083] In Fig. At approximately 5 Hz, 12 Hz, and 39 Hz, noticeable deviations A1, A2, and A3 of the frequency spectrum F from the reference frequency spectrum RF are observed, indicating a defect in vehicle 2. Server 31 is designed to detect these deviations (for example, using one or more criteria – such as exceeding a threshold value due to the difference between frequency spectrum F and the reference frequency spectrum RF at a specific frequency) and to evaluate them using a predefined criterion.

[0084] The reference frequency spectrum RF may have been determined by averaging previously recorded frequency spectra, which were determined using journeys of defect-free vehicles of the same type as vehicle 2 on a reference track that also has cobblestones like the floor 15.

[0085] The computing unit 11 can be configured to output a message via a display 24, which has been determined by the server 31 based on an assessment of deviations A1, A2, and A3 using the predefined criterion. The server 31 can be configured to send this message to the computing unit 11 for output to a driver of vehicle 2. In the example shown, this message could be, for instance, that vehicle 2 may no longer be used. Simultaneously, the server 31 can be configured to output a repair recommendation, for example, in the form of a message to an owner or lessor of vehicle 2.

[0086] The specific component that may have a defect leading to the frequency spectrum F does not need to be identified more precisely by the procedure and can be determined during inspection, for example, using visual and functional tests. The crucial point is that a defect has been detected at all.

[0087] To understand this, a mechanical equivalent diagram is needed – as in Fig. Figure 2 is helpful. Components of vehicle 2 (front tire 4a, rear tire 4b, front shock absorber 6a, rear shock absorber 6b, front suspension 7a, rear suspension 7b) are represented by corresponding mechanical symbols. In this case, it is logical to examine components on the front axle first, since these components can transmit vibrations to the mounting device 3 and the computing unit 11 via a short path.

[0088] The corresponding rigid components (especially the rim 5 on the front axle) and, if applicable, the steering rod should also be examined first. If no defect is found, components of the rear axle, which can only transmit vibrations to the mounting device 3 and the computing unit 11 via a longer path (through the frame 10), can be examined. Reference symbol list 1 system 2 vehicles 3 Holding device 4a Front tires 4b Rear tire 5. Compound consisting of a wheel rim, spokes and a hub 6a front damper 6b rear shock absorber 7a front suspension 7b rear suspension 8 handlebar 9 handlebars 10 frames 11 Computing equipment 12 Processor (of the computing unit 11) 13 inertial measurement units 14 Transmitting / receiving equipment (of the computing unit 11) 15 Floor 16a front contact area 16b rear touch area 24" Display 31 servers 32 processors (of server 31) 34 Transmitting / receiving equipment (of server 31) A1, A2, A3 deviations F Frequency spectrum RF reference frequency spectrum S vibration signal

Claims

[1] System (1), having - a vehicle (2), wherein the vehicle (2) is a two- or three-wheeled road vehicle, - an arrangement for determining changes in the mechanical vibration characteristics of the vehicle (2), wherein the arrangement comprises - a portable computing device (11) comprising at least one accelerometer, - a holding device (3) designed to hold the computing device (11) partially or completely on or in the vehicle (2), wherein the computing device (11) is configured to receive a mechanical vibration signal (S) of the vehicle (2) by means of the at least one acceleration sensor when the computing device (11) is partially or completely held by means of the holding device (3) during a journey of the vehicle (2), wherein the computing device (11) or the computing device (11) and an additionally provided server (31) is / are configured to determine a frequency spectrum (F) from the vibration signal (S) and to determine a deviation (A1, A2, A3) of the frequency spectrum (F) from a reference frequency spectrum (RF), wherein the server (31), if provided for, or any further server that is provided for, is configured - Evaluations of deviations (A1, A2, A3) in terms of frequency and amount relating to specific vehicles (2), vehicle types or vehicle fleets and / or - To make comparisons of deviations (A1, A2, A3) in terms of frequency and amount between different vehicles (2), vehicle types or vehicle fleets. [2] System (1) according to claim 1, characterized by, that the reference frequency spectrum (RF) is determined using a previous journey or a plurality of previous journeys of the vehicle (2) and / or at least one other vehicle of the same type as the vehicle (2). [3] System (1) according to claim 2, characterized by that the previous journey or the majority of previous journeys were made on a reference route and / or in a reference area. [4] System (1) according to claim 3, characterized by , that the computing device (11) is designed to record the mechanical vibration signal (S) when the vehicle (2) travels on the reference track and / or in the reference area and / or on a track whose surface corresponds to a surface of the reference track and / or a surface in the reference area. [5] System (1) according to any one of the preceding claims, characterized by, that the computing device (11) is designed to determine the frequency spectrum (F) using the Welch method. [6] System (1) according to any one of the preceding claims, characterized by , that the vehicle (2) - has a handlebar (9) and the holding device (3) is attached to the handlebar (9), - has a steering column (8) and the holding device (3) is attached to the steering column (8) or - has a frame (10) and the holding device (3) is attached to the frame (10). [7] System (1) according to any one of the preceding claims, characterized by , that - the computing equipment (11) and / or - the server (31), if provided, is / are designed to perform an assessment of the deviation (A1, A2, A3) using a predefined criterion. [8] System (1) according to claim 7, characterized by, that the computing facility (11) and / or the server (31), if provided for, is configured to send a message, in particular - a warning message, - a repair recommendation, - a safety notice and / or - to issue a shutdown order with regard to the vehicle (2), depending on the assessment of the deviation (A1, A2, A3). [9] Method for determining changes in the mechanical vibration characteristics of a vehicle (2) using a system (1) according to one of the preceding claims, comprising: - Providing a vehicle (2), wherein the vehicle (2) is a two- or three-wheeled road vehicle, - Providing an arrangement comprising a portable computing device (11) having at least one acceleration sensor and a holding device (3) configured to hold the computing device (11) partially or completely on or in the vehicle (2), wherein the computing device (11) is configured to receive a mechanical vibration signal (S) of the vehicle (2) by means of the at least one acceleration sensor when the computing device (11) is partially or completely held by means of the holding device (3) during a journey of the vehicle (2), - Holding the computing device (11) using the holding device (3), - Carrying out the journey, - Determining a frequency spectrum (F) from the oscillation signal (S) and determining a deviation (A1, A2, A3) of the frequency spectrum (F) from a reference frequency spectrum (RF) by the computing device (11) or by the computing device (11) and an additionally provided server (31), wherein the server (31), if provided, or another server performs the following steps: - Evaluations of deviations (A1, A2, A3) in terms of frequency and amount relating to specific vehicles (2), vehicle types or vehicle fleets and / or - To make comparisons of deviations (A1, A2, A3) in terms of frequency and amount between different vehicles (2), vehicle types or vehicle fleets.

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