Method and system for detecting bicycle speed

Abstract

A method for detecting the speed of a bicycle, wherein the bicycle is equipped with an ABS system on the front wheel, wherein the speed of the bicycle is identified as the speed of the rear wheel if the deceleration of the rear wheel is less than a preset threshold, otherwise the speed of the bicycle is identified as the speed of the front wheel if the pressure in the front brake circuit is lower than a preset low pressure threshold, otherwise the speed of the bicycle is an estimated speed based on the last known speed and possible deceleration.

Description

Technical Field

[0001] This disclosure relates to the field of electric bicycles, and more specifically, to a method and system for detecting the speed of a bicycle equipped with an ABS system on the front wheel. In particular, the object of the invention is a bicycle motion observer as part of a control system used within an ABS system. Background Technology

[0002] The purpose of this software-based component is to calculate real-time vehicle speed, regardless of whether individually measured wheel speeds are reliable (e.g., when one or another road wheel locks up or slips). In this way, continuous control of the ABS system is possible even in dangerous situations.

[0003] As is well known, when a cyclist brakes on a bicycle equipped with an ABS system, it is necessary to know whether the controlled wheel has locked up. This can only be done by comparing the speed of the braking wheel with the speed of the vehicle.

[0004] However, if one or both bicycle wheels lock up or slip, it is necessary to make the best estimate of the vehicle speed based on the available data. For example, in a bicycle with an ABS system on the front wheel, the following data can be obtained: front wheel speed (from a speed sensor on the front wheel), rear wheel speed (from a speed sensor on the rear wheel), and front brake circuit pressure (from a pressure transducer in the front brake hydraulic circuit).

[0005] Under normal conditions without braking, rear wheel speed can be assumed to be the most reliable source of speed data. However, if the bicycle decelerates significantly, we need to consider that the speed of one or both wheels may be unreliable. If the bicycle is decelerating sharply but there is no pressure in the front braking circuit, it can be assumed that the rear brake is working, and there is a risk of rear wheel slippage or lockup. Therefore, we should consider front wheel speed as the most reliable source of speed data. Conversely, if the vehicle is decelerating and the front braking circuit is pressurized, there is a risk of front wheel slippage or lockup. Unfortunately, since the pressure in the rear braking circuit cannot be measured, rear wheel speed cannot be assumed to be reliable.

[0006] Therefore, the object of the present invention is to estimate the speed of a bicycle in these situations in an efficient, reliable and simple manner.

[0007] This objective can be achieved by the method for detecting bicycle speed according to claim 1 and the system for detecting bicycle speed according to claim 9. The dependent claims relate to preferred embodiments of the method and system according to the invention. Summary of the Invention

[0008] According to a general embodiment of the present invention, the method detects the speed of a bicycle equipped with an ABS system on the front wheel. The method includes the following steps:

[0009] - Obtain the front wheel speed from the first speed sensor on the front wheel;

[0010] - Obtain the rear wheel speed from the second speed sensor on the rear wheel;

[0011] - Obtain the front brake circuit pressure from the pressure transducer in the front brake hydraulic circuit;

[0012] - Calculate the rear wheel deceleration.

[0013] If the rear wheel deceleration is less than a preset threshold, the bicycle speed is identified as the rear wheel speed.

[0014] If the rear wheel deceleration is greater than a preset threshold, the method includes the following further steps.

[0015] If the pressure in the front brake circuit is lower than a preset low pressure threshold, the bicycle speed is identified as the front wheel speed.

[0016] If the front brake circuit pressure is greater than a preset low pressure threshold, the bicycle speed is an estimated speed calculated based on the following sub-steps:

[0017] - The front wheel speed is stored in a storage buffer;

[0018] - When the storage buffer is full, calculate the average speed and deceleration of the front wheels;

[0019] -If the front wheel deceleration value is within the preset deceleration threshold, the bicycle speed is estimated to be the average front wheel speed value calculated last time, and the average front wheel speed and front wheel deceleration value are stored.

[0020] - If the front wheel deceleration value exceeds a preset deceleration threshold, the bicycle speed is estimated as the difference between the stored front wheel average speed value and the stored front wheel deceleration value multiplied by the time elapsed since the front wheel average speed value and front wheel deceleration value were stored.

[0021] According to one aspect of the invention, at least some method steps are implemented by a finite state machine having a first state, a second state, and a third state, wherein in the first state, the speed of the bicycle is the rear wheel speed, in the second state, the speed of the bicycle is an estimated speed, and in the third state, the speed of the bicycle is the front wheel speed. In this finite state machine:

[0022] - When the current braking circuit pressure is greater than the high pressure threshold and the difference between the front wheel speed and the rear wheel speed is greater than the preset high triangular wheel speed threshold, a transition from the first state to the second state occurs;

[0023] - When the current braking circuit pressure is less than the preset low pressure threshold, a transition from the second state to the third state occurs;

[0024] - When the current braking circuit pressure is greater than the preset high pressure threshold, a transition from the third state to the second state occurs;

[0025] - When the difference between the estimated speed and the rear wheel speed is less than the preset low triangular wheel speed threshold, a transition from the second state to the first state occurs;

[0026] - When the current braking circuit pressure is less than the preset low pressure threshold and the difference between the front wheel speed and the rear wheel speed is greater than the preset high triangular wheel speed threshold, a transition from the first state to the third state occurs;

[0027] When the difference between the front wheel speed and the rear wheel speed is less than the preset low triangular wheel speed threshold, a transition from the third state to the first state occurs.

[0028] In one embodiment, the high pressure threshold is a pressure threshold higher than that of its front wheels, which can be considered to be slipping or locked.

[0029] In one embodiment, the low pressure threshold is a pressure threshold below which the front wheels can be considered to be freely rotating.

[0030] In one embodiment, the high triangular wheel speed threshold is the following triangular wheel speed threshold: above which one of the wheels is considered to be slipping.

[0031] In one embodiment, the low triangular wheel speed threshold is the following triangular wheel speed threshold: below which two wheels are considered to be rotating at the same speed.

[0032] According to another aspect of the invention, if the detected bicycle speed changes from an old value corresponding to one of the front wheel speed, rear wheel speed, and estimated speed to a different new value corresponding to a different speed among the front wheel speed, rear wheel speed, and estimated speed, a transition detection time interval is provided during which the bicycle speed is calculated to gradually change from the old value to the new value.

[0033] In one embodiment, when the detected bicycle speed changes from an old value to a new value, the last detected value is stored, and the transition speed value is calculated as follows:

[0034] Conversion speed value = New value - (Stored value / (Elapsed time)) n ),

[0035] The elapsed time is the time interval after the change of the old value, and n < 1.

[0036] A system for detecting the speed of a bicycle equipped with an ABS system on the front wheel is also disclosed. According to a general embodiment, the system includes:

[0037] -A first speed sensor suitable for detecting front wheel speed;

[0038] -A second speed sensor suitable for detecting rear wheel speed;

[0039] -A pressure transducer suitable for detecting the pressure in the front brake hydraulic circuit;

[0040] - An electronic control unit, which is operatively coupled to a first speed sensor, a second speed sensor, and a pressure transducer.

[0041] The electronic control unit is configured to implement the above-described method for detecting bicycle speed.

[0042] According to one aspect of the invention, the electronic control unit includes a speed estimator module operatively coupled to a first speed sensor and a storage buffer, and configured to estimate the speed of the bicycle according to the following instructions:

[0043] - Load the front wheel speed into the storage buffer;

[0044] - Calculate the average speed and deceleration of the front wheels when the storage buffer is full;

[0045] - If the front wheel deceleration value is within the preset deceleration threshold, the bicycle speed is estimated as the final calculated average front wheel speed value.

[0046] - Store the average speed and deceleration values ​​of the front wheels in the storage buffer;

[0047] - If the front wheel deceleration value exceeds the preset deceleration threshold, the bicycle speed is estimated as the difference between the stored front wheel average speed value and the stored front wheel deceleration value multiplied by the time elapsed since the front wheel average speed value and front wheel deceleration value were stored.

[0048] According to one embodiment, the electronic control unit includes a speed selection state machine module operatively coupled to a first speed sensor, a second speed sensor, a pressure transducer, and a speed estimator module. The speed selection state machine module is configured to implement the speed selection state machine disclosed above.

[0049] According to one embodiment, the electronic control unit further includes a speed selection switch module operatively coupled to a first speed sensor, a second speed sensor, and a speed estimator module. The speed selection switch module is configured to selectively output one of the outputs from the first speed sensor, the second speed sensor, and the speed estimator module based on a control signal received from a speed selection state machine module.

[0050] According to one aspect of the invention, the electronic control unit further includes a discontinuity correction module, which is configured to store the last detected speed value and calculate the converted speed value as follows when the detected bicycle speed changes from an old value corresponding to one of the front wheel speed, rear wheel speed, and estimated speed to a different new value corresponding to a different speed among the front wheel speed, rear wheel speed, and estimated speed:

[0051] Conversion speed value = New value - (Stored value / (Elapsed time)) n ),

[0052] The elapsed time is the time interval after the change of the old value, and n < 1.

[0053] The simplified overview of the examples above is intended to provide a basic understanding of this disclosure. This overview is not a comprehensive summary of all anticipated aspects and is neither intended to identify key or essential elements of all aspects, nor to depict the scope of any or all aspects of this disclosure. Its sole purpose is to present one or more aspects in a simplified form as a prelude to a more detailed description of the disclosure below. In order to achieve the foregoing, one or more aspects of this disclosure include the features described and exemplarily pointed out in the claims. Attached Figure Description

[0054] The accompanying drawings, which are incorporated in and form part of this specification, illustrate one or more exemplary aspects of this disclosure and, together with the detailed description, serve to explain its principles and implementation.

[0055] - Figure 1 This is a flowchart of a method for detecting bicycle speed according to a general embodiment of the present invention;

[0056] - Figure 2 This is a diagram showing a system used to detect the speed of a bicycle;

[0057] - Figure 3 It is a time-velocity graph, which shows the behavior of the speed estimator module when the current wheel reducer remains within a predetermined threshold;

[0058] - Figure 4 This is a time-velocity graph, which shows the behavior of the velocity estimator module when the current wheel deceleration suddenly exceeds a predetermined threshold;

[0059] - Figure 5 This is a table showing the logical conditions that must be satisfied to achieve each state transition in the finite state machine according to the present invention;

[0060] - Figure 6 This is a time-velocity plot showing the behavior of the discontinuity correction module.

[0061] The following detailed description of preferred embodiments of the invention will be disclosed with reference to the accompanying drawings. Detailed Implementation

[0062] Exemplary aspects are described herein within the context of systems and methods for detecting the speed of a bicycle equipped with an ABS system. Those skilled in the art will recognize that the following description is merely illustrative and not intended to be limiting in any way. Other aspects will readily be shown to those skilled in the art who benefit from this disclosure. Implementations of the exemplary aspects, as illustrated in the accompanying drawings, will now be described in detail.

[0063] Figure 1 A general embodiment of a method for detecting bicycle speed is disclosed.

[0064] This method can be implemented using a real-time computational model that estimates vehicle speed using the following as inputs:

[0065] Hydraulic data measured in the front brake caliper circuit 10;

[0066] Front wheel speed data: 20;

[0067] Rear wheel speed data: 30.

[0068] Pressure data can be obtained from pressure transducer 12 in the front brake hydraulic circuit.

[0069] The front wheel speed data 20 can be obtained from the first speed sensor 22 on the front wheel.

[0070] The rear wheel speed data 30 can be obtained from the second speed sensor 32 on the rear wheel.

[0071] As a starting point (100), the speed of the bicycle corresponds to the speed of the rear wheel.

[0072] In step 102, the rear wheel deceleration is calculated.

[0073] In step 104, the rear wheel deceleration is compared with a preset threshold.

[0074] If the rear wheel deceleration is less than a preset threshold, the bicycle speed is identified as the rear wheel speed.

[0075] If the rear wheel deceleration is greater than a preset threshold, then in step 106, check whether there is pressure in the front brake circuit.

[0076] If the front brake circuit pressure is lower than a preset low pressure threshold, the bicycle speed is identified as the front wheel speed (step 108).

[0077] If the front brake circuit pressure is greater than a preset low pressure threshold, the bicycle speed is the estimated speed (step 110), as described below. Figure 2 The algorithm described is used for computation.

[0078] Figure 2 A block diagram of a system 200 for detecting bicycle speed according to an exemplary embodiment of the present invention is disclosed.

[0079] System 200 includes a first speed sensor 22 adapted to detect the speed of the front wheels, a second speed sensor 32 adapted to detect the speed of the rear wheels, a pressure transducer 12 adapted to detect the pressure of the front brake circuit in the front brake hydraulic circuit, an electronic control unit 40 operatively coupled to the first speed sensor 22, the second speed sensor 32, and the pressure transducer 12.

[0080] Figure 2 The electronic control unit 40 disclosed in the paper includes low-pass filters 42 and 44, a speed estimator module 46, a speed selection state machine module 48, a speed selection switch 50, and a discontinuity correction module 52.

[0081] These components of the electronic control unit 40 will now be described in detail.

[0082] Low-pass filters 42 and 44 are computational blocks that filter the raw velocity data to avoid signal spikes that could lead to calculation errors. These functions are designed to introduce the shortest possible time delay to avoid affecting the responsiveness of the ABS control system. Various filter techniques are available for this purpose. For example, a moving average filter can be implemented.

[0083] The speed estimator module 46 consists of a calculation block that estimates the vehicle speed. In some examples, the speed estimator always performs its calculations even if the result is not transferred to the ABS control system via the speed selection switch module 50.

[0084] The algorithm takes the measured front wheel speed as input and loads the speed data points into a storage buffer. When the storage buffer is full, the algorithm calculates the average of all values ​​(average wheel speed) and the difference between the highest and lowest values ​​in the buffer (which, when divided by the time required to fill the buffer, yields the wheel deceleration).

[0085] If the deceleration value is within a certain threshold, the speed estimator module outputs the final calculated average wheel speed value and submits the average wheel speed value and deceleration value to the memory.

[0086] If the deceleration value exceeds the threshold, the module's output is equal to the previously stored average wheel speed value, minus the previously stored wheel deceleration value multiplied by the time elapsed since those values ​​were stored.

[0087] Therefore, the behavior of the velocity estimator module can be summarized as follows:

[0088] If the wheel deceleration is within predetermined limits, it can be assumed that the wheels are not locked or skidding. The module's output equals the average wheel speed. This is as follows: Figure 3 It is shown schematically.

[0089] If the wheel deceleration exceeds a predetermined threshold, it can be assumed that the wheel has suddenly changed speed due to lock-up or slippage. The calculation module outputs the value if the vehicle continues to decelerate at the same rate as before the lock-up or slippage occurred. This is as follows: Figure 4 It is shown schematically.

[0090] State machine module 48 executes the decision-making process, which is used to select among available vehicle speed sources based on the following inputs:

[0091] -Filtered front wheel speed

[0092] -Filtered rear wheel speed

[0093] -Estimated speed

[0094] - Front brake pressure

[0095] -Reference constants

[0096] The speed selection state machine has three states:

[0097] First state: Selected rear wheel speed. The output of the speed selection state machine module 48 indicates to the speed selection switch module 50 that it should select the rear wheel speed.

[0098] Second state: Selected estimated speed. The output of the speed selection state machine module 48 indicates to the speed selection switch module 50 that it should select the estimated speed.

[0099] Third state: Selected front wheel speed. The output of the speed selection state machine module 48 indicates to the speed selection switch module 50 that it should select the front wheel speed.

[0100] The logical flow between states is controlled by a series of transitions, which are... Figure 2 The numbered arrows indicate the transitions. A transition occurs when each logical statement becomes true.

[0101] Therefore, during the calibration phase of ABS system development, a list of fixed parameter values ​​must be programmed into the system. These parameters are:

[0102] - High caliper pressure threshold: A pressure threshold that is higher than the pressure threshold at which the front wheel may slip or lock up.

[0103] -Low caliper pressure threshold: The pressure threshold below which the front wheel can be considered to be free to rotate.

[0104] - The high delta wheel speed threshold is the following delta wheel speed threshold: above this delta wheel speed threshold, one of the wheels is considered to be slipping.

[0105] - The low triangular wheel speed threshold is the following triangular wheel speed threshold: below this triangular wheel speed threshold, two wheels are considered to be rotating at the same speed.

[0106] The logical conditions that must be met for each transformation to occur are as follows (transformation number reference). Figure 2 (Notes). These logical conditions are as follows: Figure 5 The table is shown.

[0107] When the current braking circuit pressure is greater than the high caliper pressure threshold and the difference between the front wheel speed and the rear wheel speed is greater than the high triangular wheel speed threshold, a transition from the first state to the second state occurs (1);

[0108] -When the current brake circuit pressure is lower than the low caliper pressure threshold, a transition from the second state to the third state occurs (2);

[0109] -When the current brake circuit pressure is greater than the high caliper pressure threshold, a transition from the third state to the second state occurs (3);

[0110] - When the difference between the estimated speed and the rear wheel speed is less than the low triangular wheel speed threshold, a transition from the second state to the first state occurs (4);

[0111] - When the current braking circuit pressure is less than the low caliper pressure threshold and the difference between the front wheel speed and the rear wheel speed is greater than the high triangular wheel speed threshold, a transition from the first state to the third state occurs (5);

[0112] - When the difference between the current wheel speed and the rear wheel speed is less than the low triangular wheel speed threshold, a transition from the third state to the first state occurs (6).

[0113] The speed selection switch module 50 is operatively connected at its input to the output of the low-pass filter 44 for rear wheel speed data, the output of the low-pass filter 42 for front wheel speed data, and the output of the speed estimator module 46. The speed selection switch module 50 has a control input for receiving a switch selection request signal from the speed selection state machine module 48.

[0114] Based on the output of the state machine module 48, the correct speed value is transmitted to the output of the vehicle motion observer system 200.

[0115] The discontinuity correction module 52 is operatively connected to the output of the speed selection switch module 50 and the output of the speed selection state machine 48. Therefore, the switch selection request signal is also received by the discontinuity correction module 52.

[0116] When the speed selection switch changes between input sources, the discontinuity correction module 52 functions to avoid sudden discontinuities in the speed value.

[0117] When the discontinuity detection module 52 detects a change in the value of the switch selection request from the state machine, the last detected value from the speed selection switch module is stored in the memory.

[0118] In the subsequent calculation steps, the following output values ​​were calculated:

[0119] Output value = New speed data - (Stored data / (Elapsed time)) n )

[0120] The elapsed time is the time period since the switch selection request was changed, and n < 1.

[0121] This module behaves as follows: if a discontinuity occurs between the selected data sources, the output data is smoothed after the switch, tending towards the value from the new data source. The rate at which the new data source trend emerges depends on the value of the exponent n. The discontinuity correction block behaves as follows: Figure 6 As shown schematically.

[0122] Based on the above description, it can be understood that the estimated speed is calculated mathematically without using inertial sensors. The estimated speed is used when the speeds of both wheels are unreliable (for example, when the rear wheel speed is known to be unreliable, and pressure above a certain reference value is applied to the front brake caliper, thus potentially causing the front wheels to slip).

[0123] Advantageously, vehicle speed can be estimated without using inertial sensors, and the most reliable final calculated speed can be obtained from the inputs listed above.

[0124] The proposed computational method may require relatively low computational power, allowing the entire algorithm to run in the background while providing accurate and reliable results.

[0125] It should be noted that the term "module" as used in this disclosure refers to a real-world device, component, or arrangement of components implemented using hardware, such as by an application-specific integrated circuit (ASIC) or FPGA, or as a combination of hardware and software, such as a microprocessor system and a set of instructions that (when executed) transform the microprocessor system into a dedicated device. A module can also be implemented as a combination of both, where some functions are implemented solely by hardware, while others are implemented by a combination of hardware and software. In some implementations, at least a portion of the module, and in some cases, the entire module, can be executed on a processor of a computer system. Therefore, each module can be implemented in a variety of suitable configurations and should not be limited to any particular implementation exemplified herein.

[0126] The various aspects disclosed herein include current and future known equivalents of known modules mentioned herein by way of example. Furthermore, while various aspects and applications have been shown and described, it will be apparent to those skilled in the art, who will benefit from this disclosure, that further modifications beyond those described herein can be made without departing from the inventive concept disclosed herein.

[0127] For example, this disclosure is made with reference to a bicycle; however, it will be apparent that the inventive concept can be extended to other types of vehicles, such as other two-wheeled vehicles (e.g., scooters or motorcycles) that have ABS only on the front wheel, or other vehicles where ABS is applied to the brakes on a single axle via a single hydraulic circuit and the average speed of the wheels on the other axle is also used as an input to the system.

[0128] Furthermore, for clarity, this disclosure relates to a bicycle with an ABS system mounted on the front wheel, but those skilled in the art will appreciate from this disclosure that the inventive concept can also be applied to bicycles or other vehicles with an ABS system mounted on one or more rear wheels.

Claims

1. A method for detecting the speed of a bicycle, wherein the bicycle is equipped with an ABS system on its front wheel, the method comprising the steps of: a) Obtain the front wheel speed from a first speed sensor on the front wheel; b) Obtain the rear wheel speed from the second speed sensor on the rear wheel; c) Obtain the front brake circuit pressure from the pressure transducer in the front brake hydraulic circuit; d) Calculate the rear wheel deceleration; e) If the rear wheel deceleration is less than a preset threshold, the speed of the bicycle is identified as the rear wheel speed; otherwise: f) If the front brake circuit pressure is below a preset low pressure threshold, the bicycle speed is identified as the front wheel speed; otherwise... g) The speed of the bicycle is an estimated speed calculated based on the following sub-steps: i) Load the front wheel speed into the storage buffer; ii) When the storage buffer is full, calculate the average speed and deceleration of the front wheels; iii) If the front wheel deceleration value is within a preset deceleration threshold, the speed of the bicycle is estimated as the last calculated average front wheel speed value, and the average front wheel speed value and the front wheel deceleration value are stored. iv) If the front wheel deceleration value exceeds the preset deceleration threshold, the speed of the bicycle is estimated as the difference between the stored front wheel average speed value and the stored front wheel deceleration value multiplied by the time elapsed since the front wheel average speed value and the front wheel deceleration value were stored in sub-step iii).

2. The method according to claim 1, wherein, Steps d), e), f), and g) are implemented using a finite state machine having a first state, a second state, and a third state, wherein in the first state, the speed of the bicycle is the rear wheel speed, in the second state, the speed of the bicycle is the estimated speed, and in the third state, the speed of the bicycle is the front wheel speed, and wherein: - When the pressure in the front braking circuit is greater than the high pressure threshold and the difference between the front wheel speed and the rear wheel speed is greater than the preset high triangular wheel speed threshold, a transition from the first state to the second state occurs; - When the pressure in the front braking circuit is less than a preset low pressure threshold, a transition from the second state to the third state occurs; - When the pressure in the front braking circuit is greater than a preset high pressure threshold, a transition from the third state to the second state occurs; - When the difference between the estimated speed and the rear wheel speed is less than a preset low triangular wheel speed threshold, a transition from the second state to the first state occurs; - When the pressure in the front braking circuit is less than the preset low pressure threshold and the difference between the front wheel speed and the rear wheel speed is greater than the preset high triangular wheel speed threshold, a transition from the first state to the third state occurs; - When the difference between the front wheel speed and the rear wheel speed is less than the preset low triangular wheel speed threshold, a transition from the third state to the first state occurs.

3. The method according to claim 2, wherein, The high pressure threshold is the following pressure threshold: above which the front wheel can be considered to be slipping or locked.

4. The method according to claim 2 or 3, wherein, The low pressure threshold is the following pressure threshold: below which the front wheel can be considered to rotate freely.

5. The method according to any one of claims 2-4, wherein, The high triangular wheel speed threshold is the following triangular wheel speed threshold: above this triangular wheel speed threshold, one of the wheels is considered to be slipping.

6. The method according to any one of claims 2-5, wherein, The low triangular wheel speed threshold is the following triangular wheel speed threshold: below this triangular wheel speed threshold, the two wheels are considered to be rotating at the same speed.

7. The method according to any one of the preceding claims, wherein, If the detected bicycle speed changes from an old value corresponding to one of the front wheel speed, the rear wheel speed, and the estimated speed to a different new value corresponding to a different speed among the front wheel speed, the rear wheel speed, and the estimated speed, a transition detection time interval is provided during which the bicycle speed is calculated to gradually change from the old value to the new value.

8. The method according to claim 7, wherein, When the detected bicycle speed changes from the old value to the new value, the last detected value is stored, and the transition speed value is calculated as follows: Conversion speed value = New value - (Stored value / (Elapsed time)) n ), The elapsed time is the time period after the change of the old value, and n < 1.

9. A system for detecting the speed of a bicycle, wherein the bicycle is equipped with an ABS system on the front wheel, the system comprising: - First speed sensor, which is suitable for detecting the speed of the front wheels; - A second speed sensor, suitable for detecting rear wheel speed; - Pressure transducer, which is suitable for detecting the front brake circuit pressure in the front brake hydraulic circuit; - An electronic control unit, operatively coupled to the first speed sensor, the second speed sensor and the pressure transducer, and configured to implement a method for detecting the speed of a bicycle according to any one of the preceding claims.

10. The system according to claim 9, wherein, The electronic control unit includes a speed estimator module operatively coupled to the first speed sensor and a storage buffer, and is configured to: - Load the front wheel speed into the storage buffer; - When the storage buffer is full, calculate the average speed and deceleration of the front wheels; If the front wheel deceleration value is within a preset deceleration threshold, then the speed of the bicycle is estimated as the last calculated average front wheel speed value. - Store the average front wheel speed value and the front wheel deceleration value in the storage buffer; If the front wheel deceleration value exceeds the preset deceleration threshold, the speed of the bicycle is estimated as the difference between the stored front wheel average speed value and the stored front wheel deceleration value multiplied by the time elapsed since the front wheel average speed value and the front wheel deceleration value were stored.

11. The system according to claim 10, wherein, The electronic control unit includes a speed selection state machine module operatively coupled to the first speed sensor, the second speed sensor, the pressure transducer, and the speed estimator module, and configured to implement a finite state machine according to any one of claims 2-6.

12. The system according to claim 11, wherein, The electronic control unit further includes a speed selection switch module operatively coupled to the first speed sensor, the second speed sensor, and the speed estimator module, and configured to selectively output one of the outputs from the first speed sensor, the second speed sensor, and the speed estimator module based on a control signal received from the speed selection state machine module.

13. The system according to any one of claims 9-12, wherein, The electronic control unit also includes a discontinuity correction module, which is configured to store the last detected speed value and calculate the converted speed value when the detected bicycle speed changes from an old value corresponding to one of the front wheel speed, the rear wheel speed, and the estimated speed to a different new value corresponding to a different speed among the front wheel speed, the rear wheel speed, and the estimated speed. Conversion speed value = New value - (Stored value / (Elapsed time)) n ), The elapsed time is the time period after the change of the old value, and n < 1.

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