Method for fault detection in bicycles, device and bicycle

Abstract

A method for fault detection on a bicycle with a motor, as well as an associated device and a bicycle, is disclosed. The method comprises the steps of receiving (S1) a first speed information from a first speed sensor, receiving (S2) a second speed information from a second speed sensor, determining (S4) whether the bicycle (10) is in a calibration situation, and if so, comparing (S5) the first speed information and the second speed information, and determining (S6) a fault condition based on the comparison.

Description

Technical area

[0001] The present invention relates to a method for fault detection on a bicycle with a motor, as well as an associated device and an associated bicycle. State of the art

[0002] Bicycles with a motor to assist propulsion, such as pedelecs, are continuing to enjoy increasing popularity. Various speed sensors are used to control the system components and record the current actual values. For example, current systems record the crank speed, the rear wheel speed, and the motor speed. Any problems with the recording can lead to system failure. If, for example, the wheel speed sensor fails, the rider will no longer receive assistance because no movement of the rear wheel is detected.

[0003] DE 10 2021 200 516 A1 discloses a method and a device for determining a speed of a bicycle.

[0004] DE 10 2019 115 312 B3 discloses a device for speed control and manipulation detection for an electric bicycle. Description of the invention

[0005] It is therefore the object of the invention to at least reduce the disadvantage mentioned in the prior art.

[0006] The invention is described in the appended set of claims.

[0007] The present invention relates in a first aspect to a method for fault detection on a bicycle with a motor.

[0008] Error detection can be the detection of a sensor error or the detection of an error in another system component, such as a mechanical system component of the drivetrain. In the case of bicycles, this can, for example, be bicycles with an electric (auxiliary) motor to assist propulsion, such as pedelecs.

[0009] In a first step, the method initially comprises receiving first rotational speed information from a first rotational speed sensor. Receiving can, for example, involve wired or wireless reception of a signal from the rotational speed sensor or an indirect unit. However, it can also involve reading corresponding information from a memory. Rotational speed information can, for example, be a rotational speed signal or a signal from which the current rotational speed can be derived. As described below, the rotational speed sensor can, for example, be a wheel speed sensor, an engine speed sensor, or a crank speed sensor.

[0010] The method then includes receiving second speed information from a second speed sensor. With regard to the definition of receiving and speed information, reference is made to the above explanations. In this case, the first speed sensor differs from the second speed sensor. Thus, for example, the second speed sensor can be a different one from the crank speed sensor, the wheel speed sensor, or the engine speed sensor.

[0011] A further step then involves determining whether the bicycle is in a calibration situation. A calibration situation is a situation in which the first speed information and the second speed information have redundant signal content. This does not necessarily mean that they have the same value, but that the relationship between the first speed information and the second speed information is known, and they therefore have a known relationship to one another. If, for example, a freewheel is open between the component at which the speed is detected by the first speed sensor and the component at which the speed is determined by the second speed sensor, this speed information does not have any redundant signal content because it has no known relationship to one another, and therefore there is no calibration situation.However, if the corresponding freewheel is closed and the movement of one component is transmitted to the other component, these have redundant signal contents, since the rotation detected by the first speed sensor and the rotation detected by the second speed sensor are in a predetermined transmission ratio to each other and can be mapped to each other.

[0012] If the calibration situation described here exists, a further step involves comparing the first speed information with the second speed information. A calibration in this case can be understood, for example, as determining whether the first speed information and the second speed information have a known relationship to each other and can therefore be mapped to each other.

[0013] In the final step, a fault condition is determined based on the comparison. For example, if the first speed information and the second speed information do not have a predetermined relationship to each other, even though a calibration situation exists, it can be deduced that a fault is present in a system component. This could be a fault in one of the speed sensors, but it could also be a mechanical fault, such as a fault in a mechanical component of the transmission line.

[0014] This method thus makes it possible to perform fault detection on bicycles and thus identify a fault in a bicycle component based on redundant signal content contained in the speed information. As briefly described above, the first speed information and the second speed information can be different speed information, which can be either a crank speed, a wheel speed, or an engine speed. Accordingly, the associated speed sensors are either a crank speed sensor, a wheel speed sensor, or an engine speed sensor.

[0015] In order to further improve the error detection and to be able to localize the error to specific components, a further embodiment may provide for receiving third speed information from a third speed sensor.

[0016] Here, the above-mentioned first speed information may be a crank speed received from a crank speed sensor, the second speed information may be an engine speed received from an engine speed sensor, and the third speed information may be a wheel speed received from a wheel speed sensor.

[0017] The use of three speed information pieces, which should contain redundant signal information in a given calibration situation, thus allows for further narrowing down the error. Depending on whether a discrepancy occurs between the first and second, the first and third, and / or the second and third speed information pieces, or a discrepancy between all speed information pieces, a fault in specific system components can be inferred. Such triangular plausibility checks thus enable improved error detection and more precise localization of the fault, whether in one of the speed sensors or in one of the bicycle's mechanical components.

[0018] In one embodiment, it is also possible to use the bicycle's position information as additional information, which is determined, for example, using a GNSS sensor such as GPS. The method then comprises the further step of receiving a position signal, wherein the comparison step also includes a comparison with the position signal.

[0019] By using the position signal, further plausibility checks are possible, such as a plausibility check of the information from the wheel speed sensor.

[0020] In another embodiment, determining whether the bicycle is in a balance state may include determining whether a freewheel is engaged and / or determining whether a gear change is not currently in progress.

[0021] With regard to the freewheel, please refer to the above explanations. The torque determined by a torque sensor, for example, can also be used to determine the freewheel. However, a signal from a signal generator of the freewheel itself can also be used.

[0022] To determine whether a gear change is currently in progress, it can be determined whether a gear shift is currently in progress, and thus a gear change. If this is the case, a calibration cannot be performed because the relationship between, for example, the crank speed and the wheel speed is unknown, as this is variable at that time. The plausibility check and thus the execution of the calibration must therefore be postponed until a suitable calibration situation exists and the gear change is complete.

[0023] In a further embodiment, a previously known relationship between the rotational speeds can be used in the adjustment step.

[0024] As already explained above, the speeds detected by the speed sensors will not be identical in most situations. Rather, they will be related to each other in a known relationship, such as a linear relationship, since, for example, the wheel speed will depend on a gear ratio determined by the current gear, such as the crank speed. Such relationships, which can be defined by known gear ratios, can be used for plausibility checks and thus in the comparison step. This can be, for example, a pre-ratio of the engine, a gear ratio of a derailleur, or even a gear-dependent gear ratio.Such relationships also depend on whether the motor described here is a drive-side motor, such as a bottom bracket motor with derailleur gears, or an output-side motor, such as a mid-drive motor with a motor at the transmission output. Such relationships can, for example, be stored in a memory and retrieved depending on the current state, such as the currently selected gear.

[0025] In the step of determining a fault condition, at least one of a possible sensor defect or a defect in a mechanical component is determined. As described above, such a fault condition can be deduced from the fact that an irregularity or error is detected during the comparison of the speed signals. Depending on the occurrence of the error, the error can be narrowed down to specific components. In this case, it may not be possible to make a clear statement about a defect in a specific component, but the error can be narrowed down to certain components.Thus, in the step of determining an error condition, at least one of a possible sensor defect or a defect of a mechanical component can be determined, this being done depending on a certain deviation of the speed information, and thus on the fact in which calibration a corresponding error occurs.

[0026] In a further embodiment, a control signal can then be output based on the determined error condition. Such a control signal can control a system component of the bicycle. Such a system component can, for example, be a shift control device, which is controlled in such a way that a specific emergency gear is engaged, allowing the rider to progress further. However, the control can also involve writing or setting a specific error flag. A display device can also be controlled in such a way that a warning message is output to a user or rider.

[0027] To enable the driver to continue to move forward even in the event of a fault, other control methods implemented on a control unit can replace the output of one of the speed sensors with another speed sensor. Accordingly, one speed information can be emulated with another speed information. This allows, for example, the wheel speed information to be replaced with engine speed information or crank speed information, whereby the previously known relationship between these pieces of information can be used. This ensures continued movement and, for example, the continued use of the engine, even if a corresponding signal or speed sensor fails.

[0028] The sequence of steps, in particular the steps of receiving the speed information and determining whether the bicycle is in a calibration situation, are not limited to the sequence shown here.

[0029] The present invention further relates to an apparatus for carrying out a method according to the embodiments discussed above.

[0030] The present invention also includes a computer program product which, when executed on a corresponding device, carries out the method steps.

[0031] The present invention also relates to a bicycle with a motor, such as an electric motor, and the device discussed here for carrying out the method. Short description of the characters Fig. 1 shows a bicycle according to an embodiment. Fig. 2 shows a method according to one embodiment. Fig. 3 shows a comparison of three speed information. Detailed description of embodiments

[0032] Fig. 1 shows a bicycle 10 with a motor (not shown). Furthermore, the bicycle shown here comprises three sensors: a wheel speed sensor 11, which detects the wheel speed 11a, a crank speed sensor 12, which detects the crank speed 12a, and an engine speed sensor 13, which detects an engine speed 13a. Furthermore, the bicycle comprises a device 14 for carrying out the method described below, such as a control device.

[0033] In the Fig. In the method shown in Figure 2, first speed information, here the crank speed 12a from the crank speed sensor 12, is received in step S1. Then, second speed information, here the engine speed 13a from the engine speed sensor 13, is received in step S2. Third speed information, here the wheel speed 11a from the wheel speed sensor 11, is received in step S3. Steps S1-S3 can be executed in any order or in parallel.

[0034] Then, in step S4, it is determined whether the bicycle is in a calibration situation. In the present embodiment, this check determines whether a gear change is currently being made. If this is the case, the bicycle is not in a calibration situation. The present embodiment also checks whether a freewheel is currently open. If the freewheel is currently open, the bicycle is also not in a calibration situation.

[0035] The step of checking whether the bicycle is in a calibration situation can also be performed before or during steps S1 to S3.

[0036] If the bicycle is in a calibration situation, the calibration of the first speed information, the second speed information and the third speed information is then carried out in step S5.

[0037] Such a comparison is exemplified in Fig. 3. In the triangle plausibility check in Fig. 3, as indicated by reference numeral 15, the crank speed 12a is adjusted with the engine speed 13a, as indicated by reference numeral 16, the engine speed 13a is adjusted with the wheel speed 11a, and as indicated by reference numeral 17, the crank speed 12a is adjusted with the wheel speed 11a.

[0038] Known relationships between the speeds are used, such as the current gear ratio depending on the selected gear of a bicycle's gearshift, or the pre-ratio of the motor, also known as the electric motor (EM). If deviations or errors are detected in comparisons 15, 16, and / or 17, an error state is derived from them in step S6.

[0039] Possible error conditions are described below with reference to Fig. 3 are described.

[0040] For example, if the bicycle's motor is a drive-side motor, such as a bottom bracket motor with a derailleur, an error in calibration 15, 16, and / or 17, or even multiple errors in the calibrations, can be used to determine the type of defect. This is shown in a table for a drive-side motor in the following paragraph: - Adjustment 15 faulty (crank speed signal ≠ engine speed signal): Crank speed signal OR engine speed signal OR pre-transmission engine defective - Adjustment 16 faulty (engine speed signal ≠ wheel speed signal): Engine speed signal OR wheel speed signal OR pre-gearing engine defective OR derailleur defective - Adjustment 17 faulty (wheel speed signal ≠ crank speed signal): Wheel speed signal OR crank speed signal OR derailleur defective - Comparison 15 AND 16 incorrect: Engine speed signal or pre-ratio engine defective - Comparison 16 AND 17 incorrect: Wheel speed signal or derailleur defective - Comparison 15 AND 17 incorrect: Crank speed signal defective

[0041] If the motor is an output-side motor, such as a mid-engine / mid-gearbox with the motor at the transmission output, then, again in this situation, an error in calibration 15, 16, and / or 17 can be used to infer a corresponding sensor defect or a defect in the mechanical transmission, such as a defect in a mechanical component. This case is also presented in the table below: - Adjustment 15 faulty (crank speed signal ≠ engine speed signal): Crank speed signal OR engine speed signal OR pre-transmission engine defective - Adjustment 16 faulty (engine speed signal ≠ wheel speed signal): Engine speed signal OR wheel speed signal OR engine pre-gearing OR final gearing defective - Adjustment 17 faulty (wheel speed signal ≠ crank speed signal): Wheel speed signal OR crank speed signal OR gearbox OR final drive defective - Comparison 15 AND 16 incorrect: Engine speed signal or pre-ratio engine defective - Comparison 16 AND 17 incorrect: Wheel speed signal or final drive ratio defective - Comparison 15 AND 17 incorrect: Crank speed signal defective

[0042] In step S7, an appropriate measure can then be taken by outputting a corresponding control signal based on the determined error condition. For example, a component of the bicycle can be controlled in such a way that it shifts into an emergency gear.

[0043] If a sensor defect is detected, a sensor signal can be emulated using another sensor signal in order to maintain the bicycle's operational readiness. Reference symbol 10 bicycles 11 Wheel speed sensor 11a Wheel speed 12 Crank speed sensor 12a Crank speed 13 Engine speed sensor 13a Engine speed 14 Device 15 Adjustment of crank speed and engine speed 16 Adjustment of engine speed and wheel speed 17 Adjustment of crank speed and wheel speed S1 Receiving a first speed information S2 Receiving a second speed information S3 Receiving a third speed information S4 Determining a comparison situation S5 Match S6 Determining an error condition S7 Outputting a control signal

Claims

[1] A method for detecting faults on a bicycle (10) with a motor, comprising the steps of: - receiving (S1) a first speed information from a first speed sensor; - receiving (S2) a second speed information from a second speed sensor; - determining (S4) whether the bicycle (10) is in a calibration situation; - if the bicycle (10) is in a calibration situation, calibration (S5) of the first speed information and the second speed information; and - Determining (S6) an error condition based on the comparison, wherein - in the step of determining (S6) an error condition, at least one of a possible sensor defect or a defect of a mechanical component is determined depending on a certain deviation of the speed information. [2] The method according to claim 1, wherein - the first speed information and the second speed information different speed information are from one of: - a crank speed; - a wheel speed; and - an engine speed. [3] The method of claim 1, further comprising: - receiving (S3) a third speed information from a third speed sensor, wherein - the first speed information is a crank speed (12a) received from a crank speed sensor (12); - the second speed information is an engine speed (13a) received from an engine speed sensor (13); and - the third speed information is a wheel speed (11a) received from a wheel speed sensor (11). [4] Method according to one of the preceding claims, wherein - determining (S4) whether the bicycle (10) is in a calibration state comprises one of: - determining whether a freewheel is engaged; and - determining whether a gear change is not currently in progress. [5] Method according to one of the preceding claims, wherein - in the adjustment step (S5) a previously known relationship between the speeds is used. [6] Method according to one of the preceding claims, further comprising: - Outputting (S7) a control signal based on the determined error condition. [7] Method according to claim 6, wherein - the control signal controls a control device of the bicycle (10) in such a way that an emergency gear is switched on. [8] Method according to claim 6, wherein - the control signal controls a control device of the bicycle (10) such that the output of one of the speed sensors is replaced by an output of another of the speed sensors for use in another control method. [9] Device (14) for carrying out a method according to one of the preceding claims. [10] Bicycle (10) comprising: - an engine; and - a device (14) according to claim 9.

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