WO2014206592A1

WO2014206592A1 - Method for detecting an imbalance on a vehicle

Info

Publication number: WO2014206592A1
Application number: PCT/EP2014/057035
Authority: WO
Inventors: Christian Reichert; Gregor Dasbach; Frank Schindler; Qiulu DAI; Julian Bartholomeyczik
Original assignee: Robert Bosch Gmbh
Priority date: 2013-06-25
Filing date: 2014-04-08
Publication date: 2014-12-31
Also published as: DE102013211973A1

Abstract

The invention relates to a method and a vehicle, in particular a bicycle, for detecting an imbalance. According to the invention, a first characteristic quantity of a first periodic signal of an acceleration sensor is determined and classified, the first characteristic quantity of a predetermined class is compared with operating parameters of the vehicle, and an imbalance is detected in response to the comparison result.

Description

description

title

Method for detecting an imbalance on a vehicle Prior art

The present invention relates to a method for detecting an imbalance on a vehicle, wherein the vehicle can be in particular a bicycle. In particular, the present invention relates to a method for automated detection and signaling of an imbalance to a user or a

Maintenance operation.

The detection of imbalances and / or bearing damage by means of acoustic or visual control by persons is a time-consuming and therefore costly task. Especially in the case of entire vehicle fleets add up

Expenses for checking the vehicles as part of test drives. In general, for bicycles that are lent, for example, in the fleet (for example, offered by the Deutsche Bahn AG), damage to the

Wheel bearings or unbalance of the wheels ("bicycle eights"), if they are detected by the user at all, not by this reported to the operator or appropriate maintenance personnel

Periodically be subjected to a visual and acoustic control of bicycles, including test drives for detecting imbalances are required. Continuous monitoring of the wheel / bottom bracket and the wheels is therefore not possible. For commercially provided bicycle fleets is the

Method of optical and acoustic control time-consuming and costly, since they, apart from the labor costs, for the period of (also

routine) check not available for rental. It is therefore an object of the present invention to automatically detect imbalances on vehicles.

Disclosure of the invention The inventive method solves the above object by the automatic detection of damage to the wheel or bottom bracket or the detection of imbalance of the wheels. In this case, the information about existing imbalances on a suitable medium to the provider or the

Maintenance company to be transmitted, which purposefully deduct individual bikes from the fleet for repair from the current operation and maintain or repair can. A method is therefore proposed for detecting an imbalance on a vehicle, in particular a bicycle, with the following steps: In a first step, a first parameter of a first periodic signal of an acceleration sensor is determined and then classified. The signal is thus recognized as "periodic" and determines predefined, suitable first characteristics. These can, for example, a

Frequency, frequency spectrum, amplitude or slew rate. In addition, the respective characteristic of the signal is subsequently classified on the basis of predefined threshold values. In this case, for example, it can be detected on the basis of an amplitude of the signal whether the first periodic signal is a noteworthy imbalance. Alternatively or additionally, the frequency of the periodic signal can be examined as to whether a movable (in particular rotating) part of the vehicle due to an imbalance to generate a corresponding frequency at all able. Subsequently, the first classified parameter is compared with operating parameters of the vehicle. The operating parameters can, for example, classify a current movement / operating state of the vehicle. In particular, a cadence, a wheel frequency and / or a speed of the vehicle can be determined in order to provide a reference variable for the determined, classified first parameter. In other words, the possibility is created of determining the current operating state of mechanical components of the vehicle, whether they are responsible for the

Generation of the first periodic signal due to an imbalance in question. Subsequently, an imbalance in response to the

Comparison result (if positive) detected. For example, it may be due to a current speed of the vehicle in conjunction with the

Rolling circumference of a wheel are detected, that the wheel frequency coincides with the frequency of the first periodic signal. In appropriate

Way, imbalances within all rotating parts of the

Moving means are recognized, provided that their imbalance in a current Operating condition could be the cause of the first periodic signal. In this way, an automated detection of an imbalance on the vehicle is possible, which can be automatically reported and corrected promptly.

The dependent claims show preferred developments of the invention.

Preferably, the step of comparing further comprises the step of

Determine second characteristics of a second, in particular periodic, signal. The second signal can serve, for example, as an information source for the operating state in which individual moving parts of the vehicle are currently located. The second parameters can also be a

Amplitude, a frequency, a (flank) shape, as well as a

Frequency spectrum of the second signal include. In this way, a simple comparison variable is generated promptly, on the basis of which the first periodic signal can be detected as imbalance.

For example, the second signal by means of the same

Acceleration sensor can be detected, by means of which also the first periodic signal has been detected. The same channel of the

Acceleration sensor, alternatively or additionally, further channels of a designed as a multi-dimensional acceleration sensor

Acceleration sensor can be received and evaluated.

Alternatively or additionally, a speedometer (e.g., satellite-based, wheel-frequency-based, cadence-based, or the like) may be used for comparison.

Alternatively or additionally, a cadence sensor can do so

be evaluated whether the cadence itself can be the cause of an imbalance on the vehicle.

Alternatively or additionally, by means of the cadence sensor also in

Connection with a transmission ratio within the drive train of the vehicle to a Radumlauffrequenz or a speed of

Vehicle to be closed. Alternatively or additionally, the second signal can be determined by means of a measuring device for detecting electrical quantities of aggregates of the vehicle. As an aggregate, for example, a hub dynamo in question. Its electrical output signal is equal in several ways

Operating parameter (vehicle speed) proportional. First is his

Output voltage in amplitude depends on the cruising speed of the vehicle. Secondly, even a quantitative determination of the wheel rotation frequency is possible via a pole pitch of the hub dynamo. Alternatively or additionally, a signal, in particular its frequency, of a force sensor in the drive train (for example pedals) can be used to compare the first characteristic with a corresponding one

Allow operating parameters. This can be done, for example, such that per pedal pivot rotation two force peaks (corresponding to the two pedals) are to be expected. In a similar way could also be

Accelerometer the acceleration peaks (corresponding to the

Torque peaks) through the two pedals per wheel revolution. Since the above-mentioned sensors or devices in many modern

Vehicles (such as bicycles with electric auxiliary motor) are installed anyway, the installation of additional hardware to carry out the

inventive method.

More preferably, the method may further include locating the imbalance based on the comparison. In other words, it can not simply be reported that there is an imbalance in one of the moving parts of the vehicle

Means of locomotion, but also the moving part can be identified. The assignment takes place (as described above) via the comparison of the first periodic signal (the unbalance) or its frequency and the frequency of the parts of the vehicle which are moved as a function of the current operating parameters. Locating the imbalance can therefore be saved

(Error entry) include a defect of a respective component. Accordingly, the user or the maintenance personnel can also be shown which part is faulty. This can enable replacement parts procurement at an earlier point in time, reducing downtime and thus saving costs. As already indicated above, the operating parameters for

Comparing the first characteristic include a gear ratio within a drive train of the vehicle. For example, a

Transmission ratio between a revolution of the bottom bracket and a rotation of a wheel of the vehicle can be determined. Of course, via the gear ratio (e.g.

Speed step detection / gear selector switch) the ratio to many other moving (rotating) parts of the vehicle can be determined. Alternatively or additionally, a cadence, a speed, a wheel diameter or a wheel circumference can be determined as operating parameters. Since in particular with electrically driven vehicles (in particular electrically drivable bicycles) these operating parameters are determined anyway, it is not necessary to provide additional hardware for carrying out the method according to the invention.

Preferably, the acceleration sensor can be fixed to a frame of the vehicle. In other words, the acceleration sensor is not attached to a rotating member of the vehicle. In this way, the acceleration sensor may e.g. also be used for tilt determination for the vehicle. In this case, the acceleration sensor as well

Three-axis (3D) accelerometer be configured. In this way, different directions with respect to current acceleration values can be distinguished and evaluated separately. In this way, it is possible to classify an imbalance in an impeller of the vehicle in terms of their nature (rash, side impact, etc.) and the user of the

Vehicle or maintenance personnel for the vehicle. In this way, more concrete measures (spare parts procurement) can be taken to remedy the defect. Advantageously, a classification of the detected imbalance can also be carried out, so that a determination of a readiness for operation of the vehicle can be determined. The unbalance can be classified as "insignificant", "long-term remedial" or "remedial in the short term". Therefore, measures for ensuring a possible driving operation can be decided and initiated in view of the relevance of the imbalance. The method according to the invention preferably comprises the step of

Storing the findings regarding the imbalance and its causes. This information can be read during maintenance and used for troubleshooting. Alternatively or additionally, a

Message are sent in response to a detected unbalance to promptly report the presence of imbalance, especially more information about the imbalance and its relevance for a comfortable / safe driving. The transmission can take place, for example, via UMTS, LTE, LTE-A or other known wireless communication systems and protocols.

According to a further aspect of the invention, a vehicle, in particular a bicycle, is most preferably an electrically drivable one

Vehicle, proposed with an acceleration sensor and an evaluation unit. The evaluation unit is set up, a signal of the

Receive acceleration sensor and perform a method as has been described in detail in connection with the first-mentioned aspect of the invention. The features of the method according to the invention can be transferred in an apparent manner to the vehicle, so that a

Repetition of the features, the possible feature combinations and the benefits of avoiding repetition can be dispensed with.

Brief description of the drawings

Hereinafter, embodiments of the invention will be described in detail with reference to the accompanying drawings. In the drawings:

Figure 1 is a schematic side view of an embodiment of a vehicle according to the invention;

Figure 2 is a flow chart, visualizing steps of a

Embodiment of a method according to the invention;

FIG. 3 shows a time diagram of a second periodic signal

different speeds; and Figure 4 shows the timing diagrams shown in Figure 3, supplemented by the signals of an excited due to an imbalance in the impeller acceleration sensor. Embodiments of the invention

Figure 1 shows a bicycle 10 as a vehicle, in the front wheel 1 1 an imbalance 1 is shown symbolically. The front wheel 1 1 is equipped with a wheel speed meter 5 a, 5 b, via which a user of the bicycle 10, a speed signal on an on-board computer 3 as

Measuring device can be displayed. The front wheel 1 1 is further equipped with a hub dynamo 6 as an electrical unit. Symbolically, the hub dynamo 6 has four poles whose electrical image can be electrically evaluated in the signal of the hub dynamo 6 for detecting an impeller speed. For driving the rear wheel 12, a first pedal 13 and a second pedal 14 are mounted on the bicycle 10 via a bottom bracket 8. A force sensor 4 can be used for cadence measurement and for determining further operating parameters. In a housing 15 is a

Evaluation unit 7 for evaluating the signal of the force sensor 4 and a first acceleration sensor 2 is provided. The evaluation unit is further connected to a symbolically represented antenna 9. A processor (not shown) within the evaluation unit 7 is set up to carry out a method as has been described in detail in the context of the disclosure of the invention.

FIG. 2 is a flow chart illustrating steps of FIG

Embodiment of a method according to the invention. In step 100, the evaluation unit 7 evaluates signals of the acceleration sensor 2. In step 200, it is determined whether a periodicity is detectable in a predefined frequency range. If this is not the case (N), the method moves in step 100 with the

Signal analysis continues. If a certain periodicity is detected (Y), a determination and classification of a first parameter of the first periodic signal takes place in step 300. Subsequently, in step 400, a second parameter of a second signal is determined and classified. This signal can

For example, be provided by the force sensor 4 and / or the speedometer 5a, 5b and / or the hub dynamo 6. In step 500, it is decided whether the first characteristic of a predetermined class can be assigned. In other words, a comparison is made between the characteristics of the first and the second signal, in the course of which a correlation between the first periodic signal and the second signal is possible.

In particular, in this case, a fixed frequency ratio between the first periodic signal as a suspected imbalance and the second signal as

Reference value made at current speeds on the bicycle 10 located rotating parts. If no predefined relationship between the first signal and the second signal can be determined (N), the method continues with the signal analysis in step 100. However, if a fixed, predefined relationship between the frequency of the first signal and the frequency of the second signal is detected (Y), an imbalance is detected in step 600 and further investigations are made of the nature of the imbalance and localization thereof. For example, this may include an evaluation of further channels of the acceleration sensor designed as a 3D acceleration sensor. In this case, a distinction is made between a rash and a side impact, if the imbalance within an impeller 1 1, 12 is arranged. In step 700, a classification of the imbalance is made as to whether it is relevant to the operating comfort or safety of the bicycle. If this is not the case (N), in step 800 a corresponding

Error memory entry in a local memory of the bicycle 10 (not shown) stored. The method then proceeds to signal analysis in step 100. However, if the unbalance is significant (Y) for the user comfort or reliability of the bicycle 10, a corresponding message is sent in step 900 via a GSM module and the antenna 9 to the

Operator of the bike 10 and sent a maintenance operation.

FIG. 3 shows two voltage signals over time, which were received by the on-board computer 3 from the hub dynamo 6 at different speeds (V1, V2). With the numbers 1 to 4 are the voltage signals of a respective Radumdrehung (corresponding to a respective magnetic

Pol of the hub dynamo) numbered. Since the voltage signals of the upper graph S _V i follow each other in time more closely than the voltage peaks of the lower graph S _V 2, it can be concluded that the

Speed V1 is greater than the speed V2. Since within the same time unit in the signal S _V i exactly twice the number of

Voltage pulses with respect to the signal S _V 2 is included, the

Speed V1 is twice as high as the speed V2 become. In addition, considering the knowledge of the number of poles (in the example four) within the hub dynamo 6, the duration of one revolution of the wheel can be determined as the time period extending between identically designated voltage pulses.

FIG. 4 shows in addition to the signals S _V i, S _V 2 of the hub dynamo 6

Voltage signals U of the acceleration sensor 2. In the upper timing diagram, a respective voltage peak Ui, U ₂ , U ₃ , U _{4 occurs in} each case at the beginning of the designated voltage signal of the hub dynamo 6. In other words, results in an identical correlation Ci, C ₂ , C ₃ , C ₄ between the times of an imbalance signal Ui, U ₂ , U ₃ , U ₄ with a respective voltage pulse of the first magnetic pole of the hub dynamo 6. In the lower diagram of the figure 4, the bicycle 10 is operated at a lower speed.

According to the spreading of the voltage pulses Sv2 of the hub dynamo 6, the voltage pulses U, U ₂ are also spread. In this case, the relative allocation of the voltage pulses U, U ₂ 'to the respective voltage pulses of the signal S ^ remains the same, which leads to a corresponding correlation C _r , C ₂ >. The signals shown in Figure 4 thus suggest that an imbalance 1 within the front wheel 1 1 consists. Alternatively, an imbalance in the rear wheel 12 of the bicycle 10 could lead to a corresponding signal context.

Even if the aspects of the invention and advantageous

Embodiments with reference to the attached

Drawings illustrated embodiments have been described in detail, modifications and combinations of features of the illustrated embodiments are possible for the skilled person without departing from the scope of the present invention, the scope of which is defined by the appended claims.

Claims

claims

1 . Method for detecting an imbalance (1) on a vehicle (10), in particular a bicycle, comprising the steps:

Determining (300) and classifying (300) a first parameter of a first periodic signal (Ui, U ₂ , U ₃ , U ₄ , Ui ', U ₂ ') of an acceleration sensor (2),

Comparing (500) the first characteristics of a predetermined class with operating parameters (V1, V2) of the vehicle (10), and detecting (600) the unbalance (1) in response to the comparison result.

2. The method of claim 1, wherein the step of comparing (500) further comprises the step of determining (400) second characteristics (Ui, U ₂ , U ₃ , U ₄ , Ui ', U ₂ ') of a second, in particular periodic, Signal (S _V i, S _V2 ) includes.

3. The method of claim 2, wherein the second signal (S _V i, S _V2 ) by means of the same acceleration sensor (2) and / or by means of a

Speedometer (5a, 5b) and / or by means of a

Cadence sensor (4) and / or by means of a measuring device (3) for detecting electrical quantities (Ui, U ₂ , U ₃ , U ₄ , Ui ', U ₂ ') of aggregates of the vehicle (10), in particular a hub dynamo (6) , is determined.

4. The method according to any one of the preceding claims, wherein the characteristic comprises a frequency and / or a frequency spectrum and / or an amplitude and / or a slope.

The method of any preceding claim, wherein the method further comprises locating the imbalance (1) based on the comparison.

6. The method according to any one of the preceding claims, wherein the

Operating parameters a gear ratio within a Drive train of the vehicle (10) and / or a cadence and / or speed (V-ι, V ₂ ) and / or a wheel diameter and / or a wheel circumference include.

7. The method according to any one of the preceding claims, wherein the

Acceleration sensor (2) is fixed to a frame of the vehicle (10) and / or designed as a three-axis acceleration sensor.

Method according to one of the preceding claims further comprising a direction evaluation of the first periodic signal (Ui, U ₂ , U ₃ , U ₄ , Ui ', U ₂ ') of an acceleration sensor (2) for the assignment of the imbalance (1) to a component of the vehicle (10).

Method according to one of the preceding claims further comprising the step of classifying (700) the imbalance (1) for determining a readiness for operation of the vehicle (10).

Method according to one of the preceding claims, further comprising the step of storing (800) and / or, in particular wireless, sending (900) a message in response to a detected imbalance

(1 ) -

Vehicle, in particular bicycle (10), with an acceleration sensor

(2) and an evaluation unit (7), wherein the evaluation unit (7)

is arranged to receive a signal of the acceleration sensor (2) and perform a method according to any one of the preceding claims.