A redundancy brake control method and system for an electric motorcycle

Abstract

The application discloses a kind of redundancy brake control method and system of electric motorcycle, belong to vehicle braking field.Method includes: if brake system is unavailable after brake signal triggers brake request, activate redundancy brake function based on energy recovery, including the confirmation and distribution of recovery torque;Real-time detection vehicle slip rate;In slip rate meets the preset recovery torque arbitration condition, arbitration is carried out to current recovery torque based on slip rate;Finally, energy recovery is carried out based on current recovery torque to realize redundancy brake.The application utilizes the energy recovery function of motor to realize redundancy brake and intelligently confirm and distribute recovery torque when hydraulic brake fails;When redundancy brake causes wheel speed to be locked in low adhesion road surface, utilize slip rate torque control, help wheel speed to restore, ensure the stability of vehicle of redundancy brake.

Description

Technical Field

[0001] This invention belongs to the field of vehicle braking, and more specifically, this invention relates to a redundant braking control method and system for electric motorcycles. Background Technology

[0002] The reliability of the braking system is of paramount safety importance for electric motorcycles. However, most existing electric motorcycles use traditional hydraulic or mechanical braking systems as their sole braking method. When the braking system malfunctions due to hydraulic line leaks, excessive wear of brake pads, or other reasons, the vehicle will completely lose its braking ability, posing a significant safety risk to the rider.

[0003] In existing technologies, there are methods that utilize regenerative braking control systems as backup in case of hydraulic brake failure. These methods can be used in passenger vehicles, and their principles can also be applied to electric motorcycles that support regenerative braking. However, using regenerative braking control systems as a backup solution still has the following problems: First, excessive recovery torque can easily cause the rear wheels to lock up; Secondly, the recovery torque is fixed and cannot adapt to different driving conditions and road conditions. Third, when the vehicle passes over speed bumps or bumpy road sections, it is easy to misjudge the rear wheel slippage and reduce the recovery torque. Summary of the Invention

[0004] This invention aims to overcome the shortcomings of the prior art and proposes a redundant braking control method and system for electric motorcycles to achieve the following objectives: when hydraulic braking fails, the energy recovery function of the motor is used to realize redundant braking and intelligently confirm and distribute the recovery torque; when redundant braking causes wheel speed lock-up on low-adhesion road surfaces, slip ratio torque control is used to help wheel speed recover and ensure vehicle stability under redundant braking.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: This invention provides a redundant braking control method for an electric motorcycle, comprising: Step S1: Determine whether a braking request is triggered based on the braking signal. If triggered, proceed to the next step. Step S2: Determine if the braking system is available. If it is not available, proceed to the next step. Step S3: Activate the redundant braking function based on energy recovery, including the confirmation and distribution of the recovered torque; Step S4: Real-time detection of vehicle slip rate; Step S5: Determine whether the slip ratio meets the preset recovery torque arbitration condition. If it does, proceed to step S6; otherwise, proceed to step S7. Step S6: Arbitrate the recovery torque based on the slip ratio; Step S7: Perform energy recovery based on the current recovered torque to achieve redundant braking.

[0006] Furthermore, in step S1, the braking signal includes a switch signal emitted by the brake switch and a travel signal emitted by the brake travel sensor; if the brake switch is detected to be pressed or the brake travel is greater than a preset threshold, it is determined that a braking request is triggered; otherwise, a braking request is not triggered.

[0007] Furthermore, in step S2, the availability of the braking system is determined by acquiring the braking system availability status signal, wherein: The braking system status is monitored in real time. When a braking system fault is detected or the braking force output by the braking system is less than a preset threshold, the braking system availability status signal is set to unavailable; otherwise, the braking system availability status signal is set to available.

[0008] Furthermore, in step S2, determining whether the braking system is available also includes: In non-downhill conditions, if the change in vehicle speed is less than a preset threshold after a braking request is triggered, the braking system is deemed unusable.

[0009] Furthermore, in step S3, the confirmation of the recovered torque includes: When the braking signal is a switching signal issued by the brake switch, the corresponding recovery torque is obtained by searching a preset vehicle speed and recovery torque lookup table based on the vehicle speed signal; the vehicle speed and recovery torque lookup table has a corresponding recovery torque set for each vehicle speed. When the braking signal is the stroke signal emitted by the brake stroke sensor, the corresponding recovery torque is obtained by searching a preset vehicle speed, brake stroke and recovery torque lookup table based on the vehicle speed signal and brake stroke. The vehicle speed, brake stroke and recovery torque lookup table has a corresponding recovery torque set for each combination of vehicle speed and brake stroke.

[0010] Furthermore, the vehicle speed is calculated using the motor speed signal, and is expressed by the following formula: V = 0.3768 * nr / i; Where V represents the calculated vehicle speed; n represents the motor speed; r represents the wheel rolling radius; and i represents the transmission ratio from the motor to the wheel.

[0011] Furthermore, in step S3, for electric motorcycles with dual front and rear motors, after confirming the completion of regenerative torque, the distribution of regenerative torque includes: (1) Distribute the recovered torque to the front and rear dual motors according to the preset torque distribution ratio; (2) When the left brake is applied, the recovery torque is distributed to the rear motor; when the right brake is applied, the recovery torque is distributed to the front motor; when the left and right brakes are applied at the same time, the recovery torque is distributed to the front and rear dual motors respectively according to the preset torque distribution ratio. During torque distribution, the torque allocated to each motor is less than or equal to its rated recovery torque.

[0012] Furthermore, P = (V 整车 -V 后轮 / Vref; Where P represents the slip ratio; V 整车 V represents the actual speed of the vehicle. 后轮 Vref indicates the actual wheel speed of the rear wheels; Vref indicates the reference speed.

[0013] Furthermore, the method also includes: after determining that the slip ratio meets the preset recovery torque arbitration condition, further speed bump identification is performed, including: Calculate the second derivative of the rear wheel speed. If the value is greater than the preset amplitude threshold, it is determined to be a speed bump or bumpy road surface. In this case, no recovery torque arbitration is performed, and the process jumps to step S7. If the value is less than or equal to the preset amplitude threshold, it is determined to be a smooth road surface. In this case, the process jumps to step S6 to perform recovery torque arbitration.

[0014] The present invention also provides a redundant braking control system for an electric motorcycle, using the aforementioned redundant braking control method for an electric motorcycle, the system comprising: Brake triggering device, used to generate braking signals and send them to the vehicle controller; The chassis controller is used to send wheel speed or vehicle speed signals, as well as the braking system availability status, to the vehicle controller. The electric drive controller is used to feed back the motor speed signal to the vehicle controller; and to perform redundant braking based on energy recovery in response to the redundant braking command of the vehicle controller. The vehicle controller is used to generate redundant braking commands according to the redundant braking control method for an electric motorcycle described above.

[0015] The technical effects of this invention are as follows: (1) This invention provides an effective redundant braking means when the braking system fails or the braking force is insufficient. The braking torque generated by the recovery of motor energy replaces or supplements the traditional braking system, which significantly improves the braking safety and reliability of electric motorcycles, reduces the risk of traffic accidents caused by brake failure, and provides important safety protection for riders. (2) This invention effectively prevents rear wheel lock-up and vehicle instability during redundant braking by using a closed-loop arbitration control based on slip ratio and a speed bump recognition mechanism, ensuring that rear wheel slip is always within a safe range. At the same time, speed bump recognition avoids misjudgment of bumpy roads and protects the personal safety of riders. (3) This invention realizes the reuse of braking energy through energy recovery, converting the braking energy that was originally dissipated in the form of frictional heat into electrical energy and storing it in the power battery, thereby improving the energy utilization efficiency and driving range of the whole vehicle, taking into account both safety and economy, and conforming to the development trend of energy conservation and environmental protection of new energy vehicles. (4) The present invention makes the operation of redundant braking more in line with the rider’s braking intention through a refined torque confirmation and distribution strategy. The two signal sources of brake switch and brake stroke provide simple, reliable and refined humanized control schemes respectively. The intelligent distribution strategy of front and rear motors is in line with riding habits, improving the riding experience and comfort. Attached Figure Description

[0016] Figure 1 A flowchart of a redundant braking control method for an electric motorcycle provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of a redundant braking control system for an electric motorcycle, provided as an embodiment of the present invention. Detailed Implementation

[0017] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings. This is to help those skilled in the art to have a more complete, accurate, and in-depth understanding of the inventive concept and technical solutions of the present invention, and to facilitate its implementation. It should be noted that the terms "first," "second," etc., used in this application are only for the convenience of describing the technical solutions and to distinguish components; the corresponding component configurations may be the same or different, and are not intended to limit the scope of this application. To make the technical solutions of the present invention clearer, the present invention will be explained and illustrated through the following embodiments.

[0018] In situations where the traditional hydraulic or mechanical braking system of an electric motorcycle malfunctions or lacks sufficient braking force, a safe and reliable redundant braking control method is needed to ensure the electric motorcycle retains effective braking capability even in the event of brake system failure, thereby protecting rider safety. To address this, this embodiment proposes a redundant braking control method for electric motorcycles. Through multiple technical means, including real-time monitoring of the braking system status, intelligent confirmation and allocation of regenerative torque, arbitration correction based on slip ratio, and speed bump recognition, a safe redundant braking system is achieved in the event of brake system failure. It also supports adaptive regenerative torque confirmation and allocation, while improving vehicle stability. This method solves the technical problems of existing electric motorcycle braking systems, lack of effective redundancy, and imperfect energy recovery braking control strategies, significantly improving the braking safety and reliability of electric motorcycles.

[0019] like Figure 1 As shown, this embodiment of the invention provides a redundant braking control method for an electric motorcycle, specifically including the following steps: Step S1: Determine whether a braking request is triggered based on the braking signal. If triggered, proceed to the next step. Step S2: Determine if the braking system is available. If it is not available, proceed to the next step. Step S3: Activate the redundant braking function based on energy recovery, including the confirmation and distribution of the recovered torque; Step S4: Real-time detection of vehicle slip rate; Step S5: Determine whether the slip ratio meets the preset recovery torque arbitration condition. If it does, proceed to step S6; otherwise, proceed to step S7. Step S6: Arbitrate the recovery torque based on the slip ratio; Step S7: Perform energy recovery based on the current recovered torque to achieve redundant braking.

[0020] Referring to step S1, determine whether a braking request is triggered based on the braking signal. If triggered, proceed to the next step. This step is the starting point and trigger condition for the entire redundant braking control method. Its core design purpose is to identify the rider's braking intention in a timely and accurate manner, providing a reliable input basis for subsequent braking system availability assessment and activation of redundant braking functions. In the actual operation of an electric motorcycle, the rider's braking intention is the primary prerequisite for initiating the braking control process. If the braking request cannot be accurately detected, the subsequent redundant braking function will be impossible. Conversely, if the braking request is detected incorrectly, the redundant braking function may be activated when unnecessary, causing unnecessary energy recovery and vehicle deceleration, affecting the riding experience and energy management. Therefore, the accuracy and reliability of braking request detection are directly related to the performance of the entire redundant braking system.

[0021] Specifically, the braking signal mentioned in step S1 includes a switching signal from the brake switch and a stroke signal from the brake stroke sensor. This dual-signal-source design fully considers the actual configuration of the electric motorcycle braking system and the technical requirements at different levels. The brake switch, as a simple and reliable mechanical or electronic switching device, is usually installed at the pivot of the brake lever or brake pedal. It generates a clear switching signal when the rider operates the brake lever or brake pedal. Its advantages include rapid response, low cost, high reliability, and strong anti-interference ability. It can work stably even in harsh driving environments and is suitable for low- to mid-range electric motorcycles or cost-sensitive applications. The brake stroke sensor, on the other hand, provides more refined braking operation information. It typically uses Hall effect sensors, potentiometers, or strain gauges to detect the displacement of the brake lever or brake pedal and outputs an analog signal related to the braking force and depth. This signal not only reflects whether the rider has braked but also the intensity and urgency of the braking operation, providing richer information input for accurate confirmation of subsequent recovery torque. It is suitable for high-end electric motorcycles or applications with high braking performance requirements.

[0022] During actual testing, the vehicle controller continuously reads the brake switch signal and brake travel sensor signal at a fixed sampling period. If the brake switch is detected to be pressed (e.g., the brake lever is pressed), meaning the switch signal changes from an open state to a closed state, or if the brake travel exceeds a preset threshold (i.e., the analog signal output by the travel sensor exceeds a pre-calibrated trigger threshold), then a braking request is triggered; otherwise, no braking request is triggered. The setting of this preset threshold requires comprehensive consideration of the braking system's response characteristics, sensor measurement accuracy, signal noise levels, and the rider's operating habits. A threshold that is too small may lead to erroneous activation of the braking control process due to road bumps, vehicle vibrations, or slight touches by the rider on the brake lever, resulting in frequent false triggers. A threshold that is too large may cause delays in brake request recognition, missing the optimal redundant braking intervention opportunity in emergency braking situations. Therefore, the optimal threshold needs to be determined through extensive real-vehicle testing and data analysis.

[0023] Step S1 uses the brake switch signal and brake stroke signal as the basis for judging the braking request, realizing multi-dimensional perception of the rider's braking intention. This ensures the reliability of brake request detection and lays the foundation for subsequent fine-tuning of regenerative torque based on the intensity of braking operation. When the braking request is successfully triggered, the vehicle controller will initiate the subsequent braking system availability judgment process. This design ensures that the redundant braking control method can be activated at the correct time, avoiding system malfunctions or missed actions due to signal misjudgment. This improves the response accuracy and reliability of the entire redundant braking system, providing a solid prerequisite for subsequent safe braking control.

[0024] Refer to step S2, which determines whether the braking system is available. If it is not available, proceed to the next step. This step is the key decision-making link for activating the redundant braking function. Its core design purpose is to accurately determine the working status of the traditional braking system and only activate the energy recovery-based redundant braking function when the traditional braking system fails or the braking force is insufficient. This avoids unnecessary energy recovery braking intervention when the braking system is working normally, ensures the normal priority working logic of the braking system, and prevents conflicts and repeated braking between the two braking systems.

[0025] In step S2 of this embodiment, the availability of the braking system is determined by acquiring the braking system availability status signal. Specifically, the chassis controller monitors the braking system status in real time. When a braking system fault is detected or the braking force output by the braking system is less than a preset threshold, the braking system availability status signal is set to unavailable and sent to the vehicle controller; otherwise, the braking system availability status signal is set to available and sent to the vehicle controller.

[0026] Braking system malfunctions can include various types: insufficient brake fluid pressure due to hydraulic system leaks, in which case the brake pedal or brake lever travel will increase significantly but the braking force will be insufficient; excessive wear of brake pads leading to a decrease in the coefficient of friction, so even if the brake fluid pressure is normal, it cannot generate sufficient braking force; blockage or rupture of brake lines preventing the brake fluid from being transmitted properly, so that the brake pressure cannot be transmitted to the brake calipers; failure of the master cylinder or wheel cylinders causing the brake pressure to fail to build up or to build up slowly; air lock caused by excessively high brake fluid temperature, which causes air bubbles to form in the brake fluid and affect pressure transmission; and electronic system malfunctions such as ABS controller malfunctions and brake pressure sensor malfunctions.

[0027] Furthermore, when the braking force output by the braking system is less than the preset threshold, even without a clear fault code, braking performance may still decline. This could be due to factors such as temporary decreases in the coefficient of friction caused by brake pad thermal fade, reduced pressure transmission efficiency due to air bubbles in the brake fluid, or uneven braking caused by brake disc deformation. In such cases, while the traditional braking system may be functional in form, the actual braking force provided is insufficient for safe braking. Therefore, redundant braking functionality needs to be activated to supplement it. The preset braking force threshold needs to be determined comprehensively based on factors such as the vehicle's total mass, maximum speed, and the minimum braking deceleration required by regulations, ensuring that the vehicle still meets the basic requirements for safe braking after redundant braking intervention.

[0028] Furthermore, in the above process, the vehicle controller's determination of braking system availability relies entirely on the braking system availability status signal sent by the chassis controller. However, there is a possibility that this signal is unreliable; that is, the signal indicates availability, but the braking system is malfunctioning. To address this issue, the vehicle controller adds a redundant judgment condition: In non-downhill conditions, if the change in vehicle speed is less than a preset threshold after a braking request is triggered, the braking system is deemed unusable.

[0029] This judgment logic is designed based on the following technical principle: During normal riding on flat roads or uphill, when the rider operates the braking device, if the braking system is working properly, the vehicle should experience a significant deceleration effect, manifested as a substantial decrease in speed. If a braking request has been triggered, but the change in speed is minimal within a preset time window, it indicates that the braking system has failed to effectively generate braking force, potentially indicating a complete brake system failure or severely insufficient braking force. It is important to note that this judgment logic excludes downhill conditions. When riding downhill, the component of gravity along the slope will drive the vehicle to accelerate; even if the braking system is working properly, the speed may not decrease significantly and may even increase. Therefore, the availability of the braking system cannot be simply judged based on the change in speed.

[0030] Step S2, through the aforementioned multi-dimensional braking system availability assessment mechanism, can comprehensively and accurately identify the failure states of the braking system, including both explicit fault states and implicit insufficient braking force states. This ensures that redundant braking functions are only activated when truly needed. In summary, step S2 establishes an intelligent switching logic between the traditional braking system and the redundant braking system, avoiding unnecessary conflicts and repeated braking between the two systems. It prevents abnormal brake pedal feel and energy management confusion caused by energy recovery braking when the braking system is functioning normally. Simultaneously, it ensures that the redundant braking function can intervene promptly and reliably in the event of a braking system failure, providing continuous braking protection for the rider and significantly improving the safety and controllability of electric motorcycles in braking system failure situations.

[0031] Referring to step S3, when the braking system is unavailable, the redundant braking function based on energy recovery is activated, including the confirmation and distribution of the recovered torque. This step is the core execution link of the redundant braking control method. Its core design purpose is to convert the rider's braking intention into a specific motor recovery torque command, and to convert the braking energy into electrical energy fed back to the battery through a reasonable torque distribution strategy. This achieves both redundant braking and energy recovery economy, thus achieving a balance between safety and economy.

[0032] Confirmation of regenerative torque is the foundation of the entire redundant braking function, directly determining the effectiveness of redundant braking and the stability of vehicle operation. This embodiment adopts two different regenerative torque confirmation strategies according to different types of braking signals to adapt to the needs of different configurations and different operating habits.

[0033] When the braking signal is a switch signal issued by the brake switch, since the switch signal can only provide information on whether the braking operation is present or not, it is a binary digital signal that cannot reflect the intensity and urgency of the braking operation. Therefore, in this embodiment, the vehicle speed signal is used to retrieve a preset vehicle speed and regenerative torque lookup table to obtain the corresponding regenerative torque. In the vehicle speed and regenerative torque lookup table, a corresponding regenerative torque is set for each vehicle speed.

[0034] The braking force required by a vehicle varies at different speeds. At high speeds, the vehicle possesses greater kinetic energy, necessitating greater braking force to decelerate or stop within a reasonable distance. Simultaneously, at high speeds, the motor's rotational speed is higher, resulting in higher energy generation efficiency, allowing the motor to withstand greater regenerative torque without overheating. Conversely, at low speeds, excessive regenerative torque can easily cause the motor to stall or sudden braking, leading to the rider leaning forward and falling, especially when approaching a stop, where a large regenerative torque can produce a noticeable jerk, affecting riding comfort. Therefore, a pre-calibrated speed-to-regenerative torque table can automatically match the appropriate regenerative torque based on the current speed, ensuring braking effectiveness while avoiding vehicle instability caused by inappropriate regenerative torque. The calibration of the table requires extensive real-world testing, including braking tests at different speeds, measuring parameters such as vehicle deceleration, braking distance, motor temperature, and battery charging status, comprehensively considering safety, comfort, and energy recovery efficiency to determine the optimal regenerative torque value for each speed.

[0035] When the braking signal is the travel signal emitted by the brake travel sensor, since the travel signal can reflect the intensity of the braking operation, the greater the travel of the rider squeezing the brake lever or pressing the brake pedal, the greater the desired braking force and the higher the requirement for braking deceleration. Therefore, in this embodiment, based on the vehicle speed signal and the braking travel, a preset vehicle speed, braking travel and regenerative torque lookup table is retrieved to obtain the corresponding regenerative torque. In the vehicle speed, braking travel and regenerative torque lookup table, a corresponding regenerative torque is set for each combination of vehicle speed and braking travel.

[0036] This two-dimensional reference table design allows for more precise and user-friendly confirmation of regenerative torque, better matching the rider's braking intentions. For example, at the same speed, light braking corresponds to a smaller regenerative torque for smooth deceleration, suitable for following other vehicles or anticipatory braking; medium braking corresponds to a medium regenerative torque for moderate deceleration, suitable for general deceleration; and emergency braking corresponds to a larger regenerative torque for rapid braking, suitable for full braking in emergency situations. The calibration of the two-dimensional reference table also requires extensive real-world testing, involving numerous tests at different speeds and combinations of braking strokes, to provide a superior braking feel and higher energy recovery efficiency.

[0037] The common feature of the two recovery torque confirmation strategies mentioned above is that they both require accurate vehicle speed information. This embodiment provides two vehicle speed acquisition methods to adapt to different system configurations and sensor availability.

[0038] The first method involves directly acquiring speed data using wheel speed sensors or vehicle speed sensors. Wheel speed sensors typically employ Hall effect or magnetoelectric sensors and are mounted on the wheel hub or drive shaft to detect the wheel's rotational speed. Vehicle speed sensors, on the other hand, directly measure the vehicle's speed. This method offers high accuracy and fast response, reflecting the vehicle's actual speed in real time, making it the preferred method for obtaining vehicle speed.

[0039] The second method is to calculate it using the motor speed signal, as expressed by the following formula: V = 0.3768 * nr / i; Where V represents the calculated vehicle speed in km / h; n represents the motor speed in rpm; r represents the wheel rolling radius in meters; and i represents the transmission ratio from the motor to the wheel. This method of indirectly calculating vehicle speed through motor speed provides a reliable alternative for situations where wheel speed sensor failure, communication failure between the chassis controller and the vehicle controller, cost constraints, or simplified system configuration are required.

[0040] After confirming the regenerative torque, for electric motorcycles with only one drive motor, there is no need to distribute the regenerative torque. Most current electric motorcycles have a rear-mounted motor, so the rear axle must bear the regenerative torque. However, for electric motorcycles with both front and rear motors, the regenerative torque needs to be distributed. This embodiment provides two distribution strategies for electric motorcycles with both front and rear motors to adapt to different control requirements.

[0041] The first method is for electric motorcycles with dual front and rear motors. After confirming the completion of the recovery torque, the recovery torque is distributed to the front and rear motors according to a preset torque distribution ratio. For example, a 60 / 40 ratio in the front and rear ensures more efficient use of the front and rear tires' grip, reducing the risk of single-wheel lock-up. This distribution method is simple and direct, suitable for most normal driving conditions. The preset distribution ratio can be calibrated based on factors such as the vehicle's front and rear axle load distribution, motor power matching, and stability requirements.

[0042] The second allocation strategy is more intelligent and conforms to riding habits. Generally, when the braking system is functioning normally, the left brake lever corresponds to the rear wheel braking, and the right brake lever corresponds to the front wheel braking. Therefore, for electric motorcycles equipped with dual front and rear motors, the torque distribution strategy for redundant braking control can also be designed as follows: For electric motorcycles with dual front and rear motors, after confirming the completion of the recovery torque, when the left brake is applied, the recovery torque is distributed to the rear motor; when the right brake is applied, the recovery torque is distributed to the front motor; when the left and right brakes are pressed simultaneously, the recovery torque is distributed to the front and rear motors respectively according to the preset torque distribution ratio.

[0043] This energy recovery strategy is designed with full consideration of the braking habits and dynamic characteristics of electric motorcycles. On an electric motorcycle, the left brake typically controls the rear wheel braking, and the right brake typically controls the front wheel braking. When the rider operates the left or right brake alone, the recovered torque is distributed to the corresponding motor. When the rear brake is dominant, the vehicle's center of gravity shifts rearward, the load on the rear wheel increases, and the rear wheel's grip improves, making it less likely for the rear motor's recovered torque to cause slippage. Simultaneously, the negative torque generated by the rear motor's recovery assists rear wheel braking, reducing the burden on the mechanical brakes and preventing rear wheel lock-up and fishtailing. When the front brake is dominant, the center of gravity shifts forward, the load on the front wheel increases, and the front motor's recovered torque assists front wheel braking, improving deceleration response; furthermore, front wheel recovery is less likely to cause rear wheel instability. When both left and right brakes are operated simultaneously, it indicates that the rider has performed emergency braking or full braking. At this time, both front and rear motors participate in energy recovery simultaneously, providing greater total braking force, shortening the braking distance, and ensuring a reasonable distribution of braking force between the front and rear axles through a preset distribution ratio, maintaining the vehicle's longitudinal stability.

[0044] In addition, during torque distribution, the torque allocated to each motor is less than or equal to its rated recovery torque. This constraint ensures that the motors operate within a safe operating range, avoiding overheating, insulation damage, permanent magnet demagnetization, or mechanical damage caused by overload. The rated recovery torque is usually determined by the motor manufacturer based on parameters such as the motor's heat capacity, insulation class, and magnetic circuit design.

[0045] Step S3, through the confirmation and distribution mechanism of regenerative torque, accurately translates the rider's braking intention into motor regenerative torque commands and performs reasonable torque distribution based on vehicle configuration and driving conditions. The technical effects are twofold: firstly, energy recovery enables redundant braking, providing an effective alternative braking method in case of brake system failure, avoiding the dangerous situation of the vehicle completely losing its braking ability; secondly, through refined torque confirmation and intelligent distribution strategies, it ensures braking effect while also considering energy recovery efficiency and vehicle stability, avoiding the risk of vehicle instability caused by excessive or improperly distributed regenerative torque. This makes the redundant braking process smoother and more controllable, significantly improving the overall performance of the redundant braking system and the rider's sense of security.

[0046] Referring to step S4, real-time detection of vehicle slip ratio is a crucial monitoring step in the redundant braking control method to ensure vehicle stability. Its core purpose is to assess the relative slip state between the tires and the ground during braking, providing accurate input data for subsequent recovery torque arbitration based on slip ratio, thereby achieving closed-loop control of the recovery torque. During braking, when the braking force exceeds the adhesion between the tires and the road surface, wheel slippage occurs, meaning the wheel speed drops below the vehicle's actual speed, potentially leading to wheel lock-up. For electric motorcycles, being two-wheeled vehicles, there is a strong coupling between longitudinal and lateral stability, resulting in inherently poor stability. If the rear wheel locks up during energy recovery redundant braking, the vehicle loses lateral stability, easily leading to skidding or fishtailing, especially during turns or on uneven surfaces, with potentially severe consequences such as rider falls or even fatal injuries. Therefore, real-time detection of slip ratio is essential for ensuring vehicle safety during redundant braking and is the first line of defense against rear wheel lock-up.

[0047] Specifically, in step S4 of this embodiment, the vehicle slip ratio is calculated using the following formula: P=(V) 整车 -V 后轮 / Vref; Where P represents the slip ratio; V 整车 V represents the actual speed of the vehicle. 后轮 Vref represents the actual rear wheel speed; Vref represents the reference vehicle speed. The rear wheel speed, rather than the front wheel speed, is used for slip ratio calculation because in the energy recovery redundant braking of electric motorcycles, the recovered torque primarily acts on the rear wheel motor. The rear wheel slip state directly reflects the impact of regenerative braking on vehicle stability. Changes in the front wheel slip ratio may be caused by front wheel mechanical braking and are not directly related to energy recovery redundant braking.

[0048] The slip ratio ranges from 0 to 1. When P=0, it indicates that the wheel is in pure rolling without slip, at which point the tire and the ground are in a static friction state with the strongest lateral adhesion capability. When P=1, it indicates that the wheel is fully locked with a wheel speed of zero, at which point the tire and the ground are in a sliding friction state, and the lateral adhesion capability is almost lost. When 0<P<1, it indicates that the wheel is in a partial slip state. As P increases, the longitudinal adhesion coefficient first increases and then decreases, while the lateral adhesion coefficient continues to decline. By calculating the slip ratio in real time, the vehicle controller can continuously monitor the slip state of the rear wheels, detect potential locking risks in a timely manner, and provide accurate feedback information for subsequent arbitration control.

[0049] Step S4 provides a quantitative basis for subsequent regenerative torque arbitration, enabling the vehicle controller to dynamically adjust the regenerative torque according to the actual slip state, so as to prevent the rear wheels from locking while ensuring the braking effect, maintain the longitudinal and lateral stability of the vehicle, and provide important state monitoring support for the safe implementation of the redundant braking function.

[0050] Referring to step S5, it is determined whether the slip ratio satisfies a preset regenerative torque arbitration condition. If the condition is satisfied, step S6 is executed; otherwise, step S7 is executed. This step is a key decision link for realizing closed-loop control of the slip ratio in the redundant braking control method. Its core design purpose is to establish a logical association between the slip ratio and the adjustment of the regenerative torque. When it is detected that the slip ratio exceeds the safety threshold, the arbitration correction mechanism is activated, and when the slip ratio is within the safety range, the current regenerative torque is maintained to continue executing the energy regenerative braking, thereby realizing intelligent management of the regenerative torque.

[0051] Specifically, in step S5 of this embodiment, the preset regenerative torque arbitration conditions include: If the slip ratio is greater than the preset slip ratio threshold, it is determined that the condition is satisfied; otherwise, it is determined that the condition is not satisfied.

[0052] The setting of the slip ratio threshold directly affects the safety and braking performance of redundant braking systems, requiring comprehensive consideration of factors such as road surface adhesion coefficient, tire characteristics, vehicle dynamics response, and riding safety. Generally, for dry asphalt roads, the optimal slip ratio range for tires is between 10% and 20%, at which point the longitudinal adhesion coefficient between the tire and the road surface is maximized, braking force is strongest, and braking distance is shortest. When the slip ratio exceeds 30%, the lateral adhesion coefficient of the tire drops sharply, making the vehicle prone to sideslip. For two-wheeled motorcycles, the loss of lateral stability is extremely dangerous. Therefore, the slip ratio threshold is usually set between 15% and 25%. The specific value needs to be calibrated based on actual vehicle test data. The calibration process requires braking tests under different road surface conditions, measuring parameters such as vehicle deceleration and braking distance, and comprehensively evaluating safety and braking performance to determine the optimal threshold. Setting the threshold too high may result in the failure to initiate arbitration correction in time when the slip ratio has exceeded the safe range but has not reached the threshold, increasing the risk of rear wheel lock-up; setting the threshold too low may result in frequent arbitration correction within the normal braking slip range, causing excessive reduction in regenerative torque, affecting braking performance and energy recovery efficiency, and even causing torque fluctuations due to frequent actions of the arbitration system, affecting riding comfort.

[0053] When the slip ratio exceeds the threshold, it indicates that the rear wheels are already in or about to enter a dangerous slip state. If the recovery torque is not adjusted in time, it may lead to rear wheel lock-up and vehicle instability. Therefore, step S6 needs to be executed to arbitrate and correct the recovery torque. By reducing the recovery torque, the braking force of the rear wheels is reduced, and the slip ratio is restored to a safe range. When the slip ratio is less than or equal to the threshold, it indicates that the slip state of the rear wheels is within a safe range and the current recovery torque level is appropriate. Step S7 can be executed to recover energy based on the current recovery torque to achieve redundant braking and maintain the current braking effect and energy recovery efficiency.

[0054] Step S5 establishes a trigger mechanism for slip ratio safety monitoring. By setting a reasonable slip ratio threshold, it realizes the automatic judgment of whether the recovery torque needs to be adjusted. This avoids system oscillation and riding discomfort caused by frequent unnecessary torque adjustments due to excessively low slip ratio. It also ensures that corrective measures can be initiated in time when the slip ratio exceeds the safety limit to prevent the further development of the dangerous state. Thus, while ensuring the continuity of redundant braking, it effectively prevents the risk of rear wheel lock-up, improves the adaptability and safety of the redundant braking system, and enables the system to automatically adjust the control strategy under different road conditions and driving conditions, achieving a dynamic balance between safety and efficiency.

[0055] After determining in step S5 that the slip ratio meets the preset regenerative torque arbitration condition, the rear wheel slip ratio may still reach the threshold for activating the regenerative torque arbitration condition when the vehicle passes over a speed bump or bumpy road surface during braking, leading to false activation of the function. Therefore, this embodiment further introduces a speed bump recognition strategy to distinguish whether the abnormal increase in rear wheel slip ratio is due to a genuine slip risk caused by excessive regenerative torque, or a false slip signal caused by the rear wheels briefly lifting off the ground or bouncing when the vehicle passes over a speed bump or bumpy road surface. This avoids incorrectly reducing the regenerative torque under bumpy road conditions, affecting redundant braking performance and energy recovery efficiency, and also prevents vehicle instability caused by braking force impact when the rear wheels re-contact the ground.

[0056] Specifically, the speed bump identification strategy includes: calculating the second derivative of the rear wheel speed; if the value is greater than a preset amplitude threshold, it is determined to be a speed bump or bumpy road surface. In this case, no regenerative torque arbitration is performed, and the process jumps to step S7; if the value is less than or equal to the preset amplitude threshold, it is determined to be a smooth road surface. In this case, the process jumps to step S6 to perform regenerative torque arbitration.

[0057] The technical principle behind this judgment is that the second derivative of wheel speed reflects the acceleration of wheel speed change, i.e., the rate of change of the wheel speed change rate. When a vehicle passes over a speed bump or uneven road surface, the rear wheels experience a vertical impact, causing the wheels to momentarily leave the ground or the contact state between the tires and the ground to change drastically. This is reflected in the wheel speed signal as a sharp change in wheel speed, which may fluctuate significantly within a very short time, even dropping to zero or changing in the opposite direction instantaneously. This drastic change results in a large amplitude of the second derivative of the wheel speed. On a smooth road surface, due to excessive recovery torque causing slippage, the change in wheel speed is relatively gradual, a progressive process. The wheel speed gradually decreases as the braking force increases, and the amplitude of the second derivative of the wheel speed is smaller. Therefore, by monitoring the amplitude of the second derivative of the rear wheel speed, these two different operating conditions can be effectively distinguished.

[0058] This embodiment introduces a speed bump recognition mechanism to achieve intelligent identification and adaptive processing of special road conditions. When the vehicle passes over speed bumps or bumpy roads, it avoids erroneous reduction of regenerative torque due to instantaneous abnormalities in wheel speed signals, ensuring the continuity and stability of redundant braking. This allows the vehicle to maintain sufficient braking force when passing over speed bumps, preventing sudden loss of braking effect due to misjudgment by the control system. On smooth roads, it performs normal regenerative torque arbitration based on slip ratio, ensuring that the vehicle does not lock up due to excessive regenerative torque. This intelligent identification mechanism improves the adaptability of the redundant braking system to complex road conditions, enabling the system to provide safe and reliable redundant braking functions under various driving conditions, further enhancing the system's robustness and practicality.

[0059] Referring to step S6, the regenerative torque is arbitrated based on the slip ratio. This step is the core execution link in the redundant braking control method to realize the slip ratio closed-loop feedback control. Its core purpose is to dynamically correct the regenerative torque through the arbitration algorithm when the slip ratio is detected to exceed the safety threshold, reduce the regenerative torque to reduce the braking force of the rear wheels, thereby restoring the slip ratio to a safe range and preventing the rear wheels from locking up and the vehicle from becoming unstable.

[0060] In this application, the slip ratio is used as input, and a preset arbitration algorithm is used to arbitrate and correct the recovery torque confirmed in step S3, and finally output the arbitrated recovery torque. The arbitration algorithm includes a PI control algorithm.

[0061] PI control, or proportional-integral control, is a classic closed-loop control algorithm. It boasts advantages such as simple structure, convenient parameter tuning, and high steady-state accuracy, making it widely used in industrial control. In PI control, the proportional term responds instantly to the deviation between the current slip ratio and the target slip ratio. The larger the deviation, the greater the adjustment of the recoverable torque, quickly suppressing further increases in the slip ratio and providing a rapid dynamic response. The integral term accumulates historical deviations to eliminate steady-state errors, ensuring that the slip ratio eventually stabilizes near the target value and avoiding persistent steady-state errors.

[0062] Besides PI control algorithms, arbitration algorithms can also include PID control algorithms, which add a derivative term to PI control. This derivative term can predict the slip ratio change trend and adjust in advance, improving the system's response speed and stability. Fuzzy control algorithms use fuzzy logic to handle the nonlinearity and uncertainty of slip ratio control, requiring no precise mathematical model and exhibiting strong adaptability. Sliding mode control algorithms design a sliding surface to allow the system state to reach and remain on the sliding surface within a finite time, exhibiting strong robustness and insensitivity to parameter perturbations and external disturbances. These algorithms each have their own characteristics and can be selected and combined according to actual control requirements, computational resources, and system complexity.

[0063] Step S6 achieves adaptive adjustment of the recovery torque through slip ratio-based arbitration of the recovery torque. When the rear wheel shows signs of slippage, the recovery torque can be reduced in time to decrease the braking force on the rear wheel, restoring the slip ratio to a safe range. This effectively prevents the rear wheel from locking up, maintains the longitudinal and lateral stability of the vehicle, and ensures riding safety. When road conditions improve, such as transitioning from a wet to a dry surface, or when the vehicle speed decreases and the slip ratio decreases, the recovery torque can be appropriately increased to fully utilize the braking capacity of the motor, improve energy recovery efficiency, and increase the range. This closed-loop control mechanism enables the redundant braking system to automatically adapt to different road adhesion conditions and riding states, maximizing braking effect and energy recovery efficiency while ensuring vehicle stability. This significantly improves the intelligence and reliability of the redundant braking system, allowing riders to obtain safe and reliable redundant braking protection in various complex road conditions.

[0064] Referring to step S7, energy recovery is performed based on the current recovered torque to achieve redundant braking. This step is the final execution stage of the redundant braking control method. Its core design purpose is to transform the recovered torque command, after confirmation, allocation, and arbitration, into actual motor braking action. Braking torque is generated through the motor's generator operation mode to achieve redundant braking of the electric motorcycle, completing the closed loop from control decision to physical execution. Specifically, after calculating the current recovered torque, the vehicle controller generates a redundant braking command and sends it to the electric drive controller. The electric drive controller controls the motor's operating state according to the command to generate the corresponding recovered braking torque.

[0065] This embodiment also provides a redundant braking control system for an electric motorcycle, using the aforementioned redundant braking control method for an electric motorcycle, such as... Figure 2 As shown, the system includes: Braking triggering devices, including brake switches and brake travel sensors, are used to generate braking signals and send them to the vehicle controller; The chassis controller is used to send wheel speed or vehicle speed signals, as well as the availability status of the braking system, to the vehicle controller. It typically integrates functional units such as a wheel speed signal acquisition module, a brake pressure monitoring module, and a brake system fault diagnosis module, and is responsible for collecting and managing data from chassis-related sensors such as wheel speed sensors, vehicle speed sensors, and brake pressure sensors. The electric drive controller is used to feed back the motor speed signal to the vehicle controller; and to perform redundant braking based on energy recovery in response to the redundant braking command of the vehicle controller; and to interact with the vehicle controller through the torque interface signal. The vehicle controller is used to generate redundant braking commands according to the redundant braking control method for an electric motorcycle described above.

[0066] The present invention has been described above by way of example with reference to the accompanying drawings. Obviously, the specific implementation of the present invention is not limited to the above-described manner. Any non-substantial improvements made using the inventive concept and technical solution; or the direct application of the inventive concept and technical solution to other situations without modification, are all within the protection scope of the present invention.

Claims

1. A redundant braking control method for an electric motorcycle, characterized in that: include: Step S1: Determine whether a braking request is triggered based on the braking signal. If triggered, proceed to the next step. Step S2: Determine if the braking system is available. If it is not available, proceed to the next step. Step S3: Activate the redundant braking function based on energy recovery, including the confirmation and distribution of the recovered torque; Step S4: Real-time detection of vehicle slip rate; Step S5: Determine whether the slip ratio meets the preset recovery torque arbitration condition. If it does, proceed to step S6. Otherwise, proceed to step S7; Step S6: Arbitrate the recovery torque based on the slip ratio; Step S7: Perform energy recovery based on the current recovered torque to achieve redundant braking.

2. The redundant braking control method for an electric motorcycle according to claim 1, characterized in that: In step S1, the braking signal includes a switch signal from the brake switch and a travel signal from the brake travel sensor; if the brake switch is detected to be pressed or the brake travel is greater than a preset threshold, a braking request is triggered; otherwise, a braking request is not triggered.

3. The redundant braking control method for an electric motorcycle according to claim 1, characterized in that: In step S2, the availability of the braking system is determined by acquiring the braking system availability status signal, wherein: The braking system status is monitored in real time. When a braking system fault is detected or the braking force output by the braking system is less than a preset threshold, the braking system availability status signal is set to unavailable; otherwise, the braking system availability status signal is set to available.

4. The redundant braking control method for an electric motorcycle according to claim 3, characterized in that: Step S2, determining whether the braking system is available, also includes: In non-downhill conditions, if the change in vehicle speed is less than a preset threshold after a braking request is triggered, the braking system is deemed unusable.

5. The redundant braking control method for an electric motorcycle according to claim 1, characterized in that: In step S3, the confirmation of the recovery torque includes: When the braking signal is a switching signal issued by the brake switch, the corresponding recovery torque is obtained by searching a preset vehicle speed and recovery torque lookup table based on the vehicle speed signal; the vehicle speed and recovery torque lookup table has a corresponding recovery torque set for each vehicle speed. When the braking signal is the stroke signal emitted by the brake stroke sensor, the corresponding recovery torque is obtained by searching a preset vehicle speed, brake stroke and recovery torque lookup table based on the vehicle speed signal and brake stroke. The vehicle speed, brake stroke and recovery torque lookup table has a corresponding recovery torque set for each combination of vehicle speed and brake stroke.

6. The redundant braking control method for an electric motorcycle according to claim 5, characterized in that: The vehicle speed is calculated from the motor speed signal, and is expressed by the following formula: V = 0.3768 * nr / i; Where V represents the calculated vehicle speed; n represents the motor speed; r represents the wheel rolling radius; and i represents the transmission ratio from the motor to the wheel.

7. The redundant braking control method for an electric motorcycle according to claim 1, characterized in that: In step S3, for electric motorcycles with dual front and rear motors, after confirming the completion of regenerative torque, the distribution of regenerative torque includes: (1) Distribute the recovered torque to the front and rear dual motors according to the preset torque distribution ratio; (2) When the left brake is applied, the recovery torque is distributed to the rear motor; when the right brake is applied, the recovery torque is distributed to the front motor; when the left and right brakes are applied at the same time, the recovery torque is distributed to the front and rear dual motors respectively according to the preset torque distribution ratio. During torque distribution, the torque allocated to each motor is less than or equal to its rated recovery torque.

8. The redundant braking control method for an electric motorcycle according to claim 1, characterized in that: In step S4, the vehicle slip ratio is calculated using the following formula: P=(V 整车 -V 后轮 ) / Vref; Where P represents the slip ratio; V 整车 V represents the actual speed of the vehicle. 后轮 Vref indicates the actual wheel speed of the rear wheels; Vref indicates the reference speed.

9. The redundant braking control method for an electric motorcycle according to claim 1, characterized in that: The method further includes: after determining that the slip ratio meets the preset recovery torque arbitration condition, further speed bump identification is performed, including: Calculate the second derivative of the rear wheel speed. If the value is greater than the preset amplitude threshold, it is determined to be a speed bump or bumpy road surface. In this case, no recovery torque arbitration is performed, and the process jumps to step S7. If the value is less than or equal to the preset amplitude threshold, it is determined to be a smooth road surface. In this case, the process jumps to step S6 to perform recovery torque arbitration.

10. A redundant braking control system for an electric motorcycle, using a redundant braking control method for an electric motorcycle according to any one of claims 1-9, characterized in that: The system includes: Brake triggering device, used to generate braking signals and send them to the vehicle controller; The chassis controller is used to send wheel speed or vehicle speed signals, as well as the braking system availability status, to the vehicle controller. The electric drive controller is used to feed back the motor speed signal to the vehicle controller; and to perform redundant braking based on energy recovery in response to the redundant braking command of the vehicle controller. A vehicle controller is used to generate redundant braking commands according to the redundant braking control method for an electric motorcycle as described in any one of claims 1-9.

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