Electronic Pedal and Vehicle Control Method Based on Drive-Brake Integrated Control Model

Abstract

This invention belongs to the field of vehicles, specifically relating to an electronic pedal and a vehicle control method based on a drive-brake integrated control model. The electronic pedal includes a pedal body, an opening sensor, a feedback component, and an output component. The pedal body's travel is divided into a braking zone, a buffer zone, and a driving zone. The opening sensor detects the real-time opening of the pedal. The feedback component outputs differentiated mechanical feedback to the pedal body based on the opening, simulating the force characteristics of different spring stiffnesses in different zones, allowing both the user and the vehicle to accurately distinguish and perceive the force. The output component outputs a target torque for driving or braking the vehicle to the vehicle control system based on the opening. The control method uses a model predictive controller to dynamically update the torque adjustment command based on the vehicle state and the user-input pedal force. This invention solves the defects of existing electronic pedals used in vehicles, such as poor feedback and insufficient accuracy in recognizing user intentions.

Description

Technical Field

[0001] This invention belongs to the field of vehicles, specifically relating to an electronic pedal and a vehicle control method and vehicle based on a drive-brake integrated control model. Background Technology

[0002] With the global energy structure transformation and increasing environmental awareness, pure electric vehicles have experienced rapid development due to their advantages such as zero emissions and low noise. Electric vehicles use an electric motor drive system, which, compared to traditional internal combustion engine vehicles, offers more direct power transmission and faster response, providing a technological foundation for new driving control modes. In particular, the emergence of the one-pedal driving mode fully demonstrates the innovative potential of electric vehicles in control technology. The one-pedal driving mode is a unique control method for electric vehicles, where the driver primarily controls the vehicle's acceleration and deceleration using a single accelerator pedal, achieving integrated braking and drive control. Depressing the pedal accelerates the vehicle, and releasing it decelerates it through an energy recovery system. This design not only simplifies driving operations but also effectively improves energy efficiency. However, this new control method differs significantly from traditional driving habits, posing a challenge to drivers' adaptation and acceptance.

[0003] Existing one-pedal control technology has revealed several shortcomings in practical applications. First, most systems employ a simple linear mapping between pedal position and motor torque, failing to fully consider the mechanical characteristics of the pedal system itself. As a key component of human-machine interaction, the pedal's feel directly impacts the driving experience. Ignoring the pedal's physical characteristics leads to a lack of proper matching between the input force and vehicle response, making it difficult for the driver to precisely control the vehicle's state. Second, existing technologies exhibit significant deficiencies in control zone division and transition processing. The switching between braking, coasting, and driving states is often abrupt, lacking smooth transition areas. This design not only affects driving smoothness but may also cause unstable vehicle responses under certain conditions. Especially in scenarios requiring precise speed adjustment, such as parking or following other vehicles, the control precision of existing systems is insufficient to meet practical needs. Furthermore, current one-pedal control strategies generally lack adaptability to different driving conditions. Whether in frequent stop-and-go traffic in urban areas or stable cruising on highways, the system uses the same control parameters, failing to optimize and adjust according to actual driving scenarios. This one-size-fits-all control approach limits the practicality of single-pedal driving and impacts driving safety and comfort. More importantly, existing systems are inadequate in recognizing driver intentions. Different driving intentions, such as emergency braking, normal deceleration, and slow coasting, require different control responses, but current technology often only judges these intentions based on changes in pedal position, lacking comprehensive analysis of multi-dimensional information such as pedal operation speed and force. This leads to the system's inability to accurately understand the driver's true intentions at certain critical moments, potentially creating safety hazards.

[0004] In summary, while one-pedal driving mode offers significant advantages in improving energy efficiency and simplifying operation, existing technologies still have many shortcomings in areas such as pedal mechanics modeling, control strategy optimization, adaptive operation, and intent recognition. Therefore, there is an urgent need to develop an intelligent one-pedal control system based on pedal structural mechanics to enhance the driving experience and safety performance of electric vehicles. Summary of the Invention

[0005] To address the shortcomings of existing electronic pedals in vehicles, such as poor feedback and insufficient accuracy in recognizing user intentions, this invention provides an electronic pedal and a vehicle control method and vehicle based on a drive-brake integrated control model.

[0006] This invention is achieved using the following technical solution:

[0007] An electronic pedal includes a pedal body, an opening sensor, a feedback component, and an output component.

[0008] The pedal body's opening range is 0-100%, with the travel intervals [0, 30%), [30%, 35%), and [35%, 100%) designated as the braking zone, buffer zone, and driving zone, respectively. The opening sensor detects the real-time opening of the pedal along a preset travel distance. i .

[0009] The feedback component is connected to the pedal body and is used to adjust according to... i The system outputs corresponding mechanical feedback to the pedal body. This mechanical feedback includes: in the braking zone, the feedback component simulates the force-feel characteristic of a spring stiffness that increases non-linearly as a quadratic function with pedal opening; the stiffness is relatively low initially as the pedal opening increases, gradually increasing with the pedal opening. In the buffer zone, the feedback component simulates the force-feel characteristic of a soft spring with constant stiffness. In the actuation zone, the feedback component simulates the force-feel characteristic of a spring stiffness that increases linearly with pedal opening; and the initial stiffness of the actuation zone is equal to the constant stiffness of the buffer zone to provide progressive force feedback.

[0010] The output component is used to determine the output based on the data. i Outputting a target torque to the vehicle control system for driving or braking the vehicle; including: outputting torque in the braking zone... i Negatively correlated braking torque; output in buffer zone and i A buffer torque that is related to and gradually converts from braking torque to driving torque; output in the driving region and i The driving torque is positively correlated with the pedal force.

[0011] The present invention also includes a vehicle control method based on a drive-brake integrated control model, which is applied to vehicles employing the aforementioned electronic pedals, and includes the following steps:

[0012] S1: Real-time acquisition of pedal opening degree i And calculate the rate of change of pedal opening. .

[0013] S2: According to i Identify the current pedal travel range and combine it with the mechanical balance equations. i and Calculate the pedal force applied by the driver F driver :

[0014] ;

[0015] In the above formula, F driver The pedal force applied to the driver; F inertia The force is due to the inertia of the pedal. F spring ( i The spring restoring force of the pedal is denoted as . This refers to the damping force of the pedal. This refers to the friction force of the pedal.

[0016] S3: Vehicle speed relative to wheels v acceleration a slip ratio l and actual motor torque T ac Discrete sampling is performed to obtain the current state of the vehicle. x , And predict the next state of the vehicle based on the vehicle's dynamics model.

[0017] S4: According to i Generate a target torque for driving or braking the vehicle and use it as the torque demand at the current moment. y m [ k Then, the preset cost function is applied in conjunction with the vehicle's state. J (Δ u [ k The optimization solution is then performed to obtain the optimal torque change that satisfies the constraints and minimizes the cost function. sequence:

[0018] ;

[0019] In the above formula, and r These are the weighting coefficients for each control objective; express k Predicted k +i Predicted velocity value at any given time; This represents the expected velocity reference value at time k+i; express k Predicted k + i Predicted acceleration values ​​at time 1; express k + i The expected acceleration reference value at any given time; express k Predicted k + i The predicted value of the rear wheel slip ratio at time t; express k + i Reference value for the expected rear wheel slip ratio at any given time; express k Predicted k + i The predicted value of the actual motor torque at any given time; express k + i Reference value for the actual expected motor torque at any given time; express k + i The change in rear axle braking torque at any given time.

[0020] S5: Based on the optimal torque change at the current moment in the sequence. The system issues torque adjustment commands to the vehicle to adjust its output torque.

[0021] S6: Repeat steps S1-S5 at each subsequent sampling time, dynamically adjust the torque adjustment command according to the new vehicle status and the pedal force input by the user, so that the real-time torque output by the vehicle can follow the torque demand.

[0022] The present invention also includes a vehicle that employs the aforementioned electronic pedal and a model predictive controller. The model predictive controller employs the aforementioned vehicle control method based on a drive-brake integrated control model to dynamically update torque adjustment commands according to the vehicle state and the pedal force input by the user, thereby enabling the real-time torque output by the vehicle to follow the torque demand.

[0023] The technical solution provided by this invention has the following beneficial effects:

[0024] This invention presents a novel electronic pedal that uses the pedal force applied by the driver as one of the control inputs. By establishing a pedal dynamics balance equation and comprehensively considering the pedal's inertia, spring, damping, and friction characteristics, it achieves accurate recognition of the driver's operating intentions. The electronic pedal proposes a zoned nonlinear force-torque mapping strategy. This scheme divides the pedal into braking, buffer, and driving zones based on its position, with different mapping relationships used in each zone, achieving a smooth transition between braking and driving.

[0025] This invention also establishes a zoned spring stiffness model in the electronic pedal based on the pedal travel. The braking zone uses increasing stiffness to provide progressive braking force feedback, the buffer zone uses constant low stiffness to simulate the "neutral" feel, and the drive zone uses linearly increasing stiffness to prevent accidental operation. This significantly improves the intuitiveness and safety of pedal operation. Furthermore, this invention achieves a good match between force feedback and vehicle response through pedal mechanics modeling, allowing the driver to intuitively feel the vehicle status through changes in pedal force. This solves the problem of the disconnect between the operating feel and actual response in existing control modes, significantly improving the driving experience and control precision.

[0026] This invention designs a model predictive controller based on the longitudinal dynamics model of a vehicle. With vehicle speed, acceleration, slip ratio and actual motor torque as state variables, the optimal control sequence is solved through rolling optimization. Under the premise of satisfying multiple constraints, it achieves accurate tracking of the torque required by the driver, thereby improving control accuracy and system robustness. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the electronic pedal provided in Embodiment 1 of the present invention.

[0028] Figure 2 This is a flowchart of the electric vehicle control strategy based on the integrated drive and braking control model provided in Embodiment 3 of the present invention.

[0029] Figure 3 The curves showing the change of pedal opening and the rate of change of opening over time were used to test the experiment.

[0030] Figure 4 This is to test the curves of the control variables changing over time in the experiment.

[0031] Figure 5 This is a curve comparing the actual vehicle speed with the reference speed during the test experiment.

[0032] Figure 6 This is a curve comparing the actual vehicle speed with the reference speed during the test experiment.

[0033] Figure 7 This is a curve comparing the actual motor torque value with the reference value in the test experiment. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0035] Example 1

[0036] Unlike traditional gasoline-powered vehicles where the accelerator and brake pedals are linked to the vehicle's drive and braking systems via linkage mechanisms, allowing the system to recognize the user's intention and adjust the status of other subsystems based on the degree of pressure applied to the pedals to achieve acceleration and braking, this embodiment provides an electronic pedal. This electronic pedal does not link with other subsystems through mechanical transmission components. Instead, it simulates the mechanical experience of a user on a traditional pedal, enabling real-time monitoring of the pedal force and pedal opening changes. This allows it to recognize the user's operational intentions and output corresponding torque control targets to the vehicle.

[0037] In the electronic pedal designed in this embodiment, when the electronic pedal interacts with the vehicle control system, the pedal force applied by the driver is used as one of the control inputs. By establishing a pedal dynamics balance equation, comprehensively considering the pedal's inertia, spring, damping, and friction characteristics, accurate recognition of the driver's operating intentions is achieved. When the electronic pedal interacts with the user, the pedal position is divided into braking, buffer, and driving zones based on the changes in the pedal's opening degree, and a zoned spring stiffness model is established based on the pedal travel. This achieves a good match between force feedback and vehicle response, allowing the driver to intuitively feel the vehicle's state through changes in pedal force. This solves the problem of the disconnect between the operating feel and actual response in existing control modes, significantly improving the driving experience and control precision.

[0038] Specifically, the electronic pedal provided in this embodiment includes a pedal body, an opening sensor, a feedback component, and an output component. The pedal body's opening range is 0-100%. Based on this, the control interval division principle adopts the fixed zero-position division method of integrated drive and brake control: the travel intervals [0, 30%), [30%, 35%), and [35%, 100%) are respectively designated as the braking zone, buffer zone, and drive zone. The opening sensor is used to detect the real-time opening of the pedal along a preset travel distance. i This allows for real-time feedback based on different opening ranges, and the generation of corresponding torque control commands in conjunction with the preset pedal force-torque mapping.

[0039] In this embodiment, the division of the pedal travel aligns with the driver's intuitive operating habits: the lower the pedal position (the deeper it is pressed), the larger the angle value, consistent with the accelerator pedal operation logic of traditional gasoline vehicles. Simultaneously, this division facilitates subsequent control algorithm design, ensuring the braking zone is located in the low-angle range and the driving zone in the high-angle range, conforming to the basic logic of integrated drive and braking control operation.

[0040] The feedback component is connected to the pedal body and is used to adjust according to... i The system outputs corresponding mechanical feedback to the pedal body. Since the feedback component in this embodiment aims to provide different force characteristics to the user across different travel ranges, allowing the user to intuitively distinguish the current range and perform actions consistent with their actual intentions, thus avoiding misoperation, the feedback component in this embodiment is not suitable for using conventional springs with a single mechanical characteristic. In practical applications, the feedback component in this embodiment is essentially a "simulated spring," which, through components such as a motor, simulates the mechanical characteristics of springs with different stiffnesses based on changes in pedal opening, allowing the user to intuitively feel the changes in spring stiffness.

[0041] Specifically, the feedback component in this embodiment outputs mechanical feedback including: in the braking zone, the feedback component simulates the force-feel characteristic of spring stiffness increasing non-linearly as a quadratic function with pedal opening; the stiffness is relatively small in the initial stage of pedal opening increase; and the stiffness gradually increases as pedal opening increases. In the buffer zone, the feedback component simulates the force-feel characteristic of a soft spring with constant stiffness. In the driving zone, the feedback component simulates the force-feel characteristic of spring stiffness increasing linearly with pedal opening; and the initial stiffness of the driving zone is equal to the constant stiffness of the buffer zone to provide progressive force feedback.

[0042] Correspondingly, the output component is used to determine the output based on the given information. i Outputting a target torque to the vehicle control system for driving or braking the vehicle; including: outputting torque in the braking zone... i Negatively correlated braking torque; output in buffer zone and i A buffer torque that is related to and gradually converts from braking torque to driving torque; output in the driving region and i The driving torque is positively correlated with the pedal force.

[0043] In summary, in the feedback and output logic of the electronic pedal provided in this embodiment, when the real-time pedal opening is in the braking zone [0, 30%), the vehicle is in a braking state, and the pedal force is mainly used to control the braking intensity. Within this range, the driver adjusts the braking intensity by controlling the pedal depth and pedal force, achieving full-range control from slight deceleration to emergency braking. Within this range, the vehicle is in a braking state; the smaller the pedal angle, the greater the braking force. Within this range, the driver adjusts the braking intensity by controlling the pedal depth; fully releasing the pedal provides maximum braking force for emergency braking; lightly releasing it provides slight braking, suitable for slowing down and precise stopping. The braking zone occupies 30% of the pedal travel, providing sufficient braking control accuracy.

[0044] When the pedal opening is within the [30%, 35%) buffer zone, the vehicle is in a transitional and buffered state from braking to driving. To avoid the abrupt change between braking and driving affecting the user's vehicle control, this embodiment provides a control logic similar to the "neutral" position in traditional vehicles within the buffer zone. This newly added narrow transition zone is the key to the integrated drive-brake control strategy of this embodiment, which can solve the driving discomfort that may be caused by direct switching between braking and driving. Within this zone, the vehicle does not generate significant braking force or driving force, but gradually and smoothly switches from a state of outputting a low level of braking torque to a low level of driving torque, producing a coasting state similar to that of a traditional fuel vehicle when the accelerator is released but the brake is not applied. This provides the user with sufficient reaction time while maintaining a smooth transition of vehicle state.

[0045] Finally, when the pedal opening is in the [35%, 100%) drive zone, the vehicle is in drive mode, and the pedal force is mainly used to control the drive torque. The drive zone occupies 65% of the pedal travel, providing the driver with ample acceleration control range. Within this range, the pedal position and pedal force jointly determine the magnitude of the drive torque, ensuring both smooth start-up and strong acceleration performance when needed.

[0046] The three-section division method used in the electronic pedal of this embodiment fully considers the driver's operating habits and vehicle dynamics characteristics. Through reasonable section setting and transition design, the smoothness and controllability of the integrated drive and braking control operation are achieved.

[0047] The feedback component of the electronic pedal provided in this embodiment serves two purposes: firstly, it provides differentiated mechanical feedback to the user when the pedal is depressed, based on the current travel range of the pedal body; secondly, it controls the pedal opening to quickly recover when the user releases the pedal body. Essentially, this process simulates the function of the spring connected in the linkage mechanism of the pedal body. However, because the feedback component in this embodiment needs to provide different feedback for different travel ranges, this "simulated spring" actually simulates the force characteristics of three different springs when the real-time opening of the pedal body is in one of the three travel ranges. In this embodiment, the design of the feedback component directly affects the driver's operating experience; using different spring characteristics for different travel ranges can match corresponding functional requirements. This non-linear spring design allows for good consistency between the pedal force feedback and the vehicle response, improving the driving experience.

[0048] Specifically, the spring stiffness in the braking zone changes non-linearly with the pedal position, simulating the force-feel characteristics of a traditional brake pedal. The stiffness is low at the initial braking stage, facilitating precise control of slight braking; as the pedal depth increases, the stiffness gradually increases, providing clear force feedback and preventing misoperation. Therefore, the stiffness function of the spring simulated by the feedback component in the braking zone of the electronic pedal in this embodiment is:

[0049] ;

[0050] In the above formula, k brake This represents the simulated spring stiffness; k b0 , k b1 and k b2 These represent the constant term, first-order coefficient, and second-order coefficient of the braking zone stiffness function, respectively. In practical applications, these parameters are obtained through actual vehicle calibration and, combined with objective force-displacement measurement data, are determined through iterative optimization to ensure that the braking feel conforms to the operating habits of most drivers. For example, in the typical scheme of this embodiment, the constant term coefficient... k b0 =2N / %, which, as the initial stiffness coefficient, reflects the gentle characteristics of the initial braking phase, allowing the driver to precisely control small-amplitude braking, suitable for conditions such as following other vehicles and slow-moving situations. The linear term coefficient characterizes the linear increase of stiffness; in this embodiment, it is taken as [value missing]. k b1 =0.1N / % 2 This can provide progressive force feedback enhancement. The quadratic term coefficient reflects the rapid increase in stiffness during deep braking; in this embodiment, the quadratic term coefficient is set to a value of k b2 =0.005N / % 3.

[0051] The spring restoring force in the braking zone is obtained by integrating the stiffness function; this integral relationship ensures the continuity of the force-displacement characteristics. Correspondingly, in this embodiment, the spring restoring force output by the feedback component in the braking zone... F spring as follows:

[0052] ;

[0053] In the above formula, i max This indicates the maximum opening of the braking zone.

[0054] In the buffer zone, a constant spring stiffness is used to simulate the characteristics of a soft spring, providing a gentle transition feel; in this embodiment, the stiffness function of the spring simulated by the feedback component in the electronic pedal is:

[0055] ;

[0056] In the above formula, k 0 indicates the preset stiffness value of the buffer. In practical applications, k 0 = 1N / %.

[0057] The spring force calculation for the buffer zone needs to ensure continuity with the end of the braking zone. Accordingly, in this embodiment, the feedback component outputs the spring restoring force in the buffer zone. F spring as follows:

[0058] .

[0059] In the buffer zone, the lower stiffness value gives the zone a distinctly "soft" feel, allowing the driver to clearly perceive entering the buffer zone and helping to accurately control the vehicle's state.

[0060] In the drive zone, the spring stiffness increases linearly with pedal depth, providing progressive force feedback. In this embodiment, the feedback component in the electronic pedal simulates the spring stiffness function as follows:

[0061] ;

[0062] In the above formula, This is the initial stiffness of the driving region; in this embodiment, =1.5N / %, which is slightly higher than the buffer, thus providing a clear sense of interval switching. In this embodiment, the stiffness growth rate of the driving region is... =0.08N / % 2 This allows the carbon fiber plate to generate appropriate force when pressed deeply, preventing excessive acceleration caused by misoperation.

[0063] The spring force in the drive zone also needs to maintain continuity; therefore, the spring restoring force output by the feedback component in the drive zone... F spring as follows:

[0064] .

[0065] In summary, the progressive stiffness design adopted in the drive zone in this embodiment ensures both the handling precision during start-up and low-speed driving, and provides sufficient pedal support when high power output is required.

[0066] The electronic pedal in this embodiment can calculate the pedal force applied by the user to the pedal body by constructing the overall mechanical equilibrium equation of the pedal system, thereby establishing a mapping relationship between the driver's pedal operation information and the pedal force. In this embodiment, based on Newton's second law, considering the rotational inertia, spring restoring characteristics, damping characteristics, and frictional characteristics of the pedal system, a complete pedal dynamics model is established. This model can accurately reflect the relationship between the force applied by the driver to the pedal and the pedal motion state, providing accurate input information for subsequent control strategies. Specifically, the mechanical equilibrium equation of the electronic pedal in this embodiment can be expressed as:

[0067] ;

[0068] In the above formula, F driver The pedal force applied to the driver is a direct reflection of the driver's intention. The driver applies the pedal force by acting on the pedal surface with their foot, and the force is transmitted to the pivot shaft via the pedal lever, thereby adjusting the opening of the pedal body. F inertia This refers to the inertial force of the pedal; the inertial force is the inertial force generated by the pedal and its related moving parts due to changes in their own mass and motion state (such as acceleration, deceleration, and speed change). This force directly affects the pedal's feel, system stability, and energy loss, reflects the mass distribution characteristics of the pedal system, and influences the pedal's dynamic response speed. F spring ( i ) is the spring restoring force of the pedal; the spring restoring force is related to the pedal opening (position), and this force provides the pedal's reset function, enabling the pedal to automatically return to its initial position when no external force is applied. This is the pedal damping force; the pedal damping force is related to the pedal opening and angular velocity, and is used to dissipate system energy, prevent pedal oscillation, and provide appropriate operating damping. This refers to pedal friction; pedal friction is related to the angular velocity of pedal movement and includes bearing friction, seal friction, etc., and affects the smoothness of pedal operation.

[0069] In the feedback component of the electronic pedal in this embodiment, the damping and friction characteristics of the electronic pedal have an important impact on the operation quality. A reasonable damping design can eliminate pedal vibration and provide a stable operating feel; appropriate friction can help the driver maintain the pedal position and reduce fatigue during long-term driving.

[0070] Specifically, in the practical application of this embodiment, the pedal damping force F damping The following nonlinear model is used for calculation:

[0071] ;

[0072] In the above formula, c 0 is the basic damping coefficient; in the typical scheme of this embodiment... c 0 = 0.5. α This is the location correlation coefficient; in a typical scheme of this embodiment, α =0.01, this value allows the damping to increase with the pedal depth, providing stronger damping when the pedal is pressed deeply, thus enhancing operational stability. β For the velocity correlation coefficient, in this embodiment β =0.05, this coefficient reflects the nonlinear damping characteristics during high-speed motion. It increases damping during rapid pedaling to prevent over-aggression, while maintaining low damping during slow adjustments for precise control. This speed-dependent nonlinear design is particularly suitable for emergency braking scenarios, providing additional damping force to help the driver control pedal action.

[0073] Furthermore, the pedal friction in this embodiment F friction The following combined model of Coulomb friction and viscous friction is used for calculation:

[0074] ;

[0075] In the above formula, F c This embodiment uses Coulomb friction. F c =10N; Coulomb friction provides basic resistance to motion, which plays a major role when the pedal is in a stationary or moving state, helping to keep the pedal in a specific position. c v The coefficient of viscous friction; in this embodiment c v =0.2, the coefficient of viscous friction is proportional to velocity, providing continuous resistance during pedal movement. (Sign function) sign (•) Used to determine the direction of motion, ensuring that the frictional force is always opposite to the direction of motion.

[0076] The presence of Coulomb friction gives the pedal a certain position-holding ability, allowing the driver to keep the pedal stable in a certain position without continuous force, which can significantly reduce driving fatigue during long-distance driving. Viscous friction provides smooth motion resistance, improving the smoothness of operation. The combination of these two frictional forces ensures the stability of pedal operation without excessively increasing the operating force, achieving a balance between operating comfort and functionality.

[0077] Based on the mechanical equilibrium equations constructed above, this embodiment can utilize the principle of inverse dynamics to measure the motion state of the pedal (such as real-time opening). i The force applied to the pedal by the driver is reversed. F driver This method avoids the difficulty of directly measuring pedal force and reduces the application cost of the solution.

[0078] In the output component of the electronic pedal in this embodiment, force-torque mapping is the core of the integrated drive and braking control, translating the driver's operational intentions into the vehicle's power output. This embodiment designs different mapping strategies for different travel ranges of the electronic pedal to adapt to different needs of braking, transition, and driving. The design of the mapping relationship fully considers ergonomic principles and vehicle dynamics characteristics, ensuring that the driver can intuitively and accurately control the vehicle.

[0079] For example, in the braking zone, the torque mapping used in this embodiment employs a nonlinear amplification model, resulting in moderate braking with a small pedal force and forced braking with a large pedal force. This design aligns with the driver's psychological expectations and operational characteristics in emergency situations. Specifically, the output braking torque... T brake Satisfy the following formula:

[0080] ;

[0081] In the above formula, K brake This is the maximum braking torque; in practical applications, this value can be determined by the capabilities of the motor and braking system, thus ensuring sufficient braking capacity to meet the requirements of various braking conditions; typically, K brake =300N•m. F refb For reference braking force; typically, F refb =100N•m. F driver The pedal force applied to the driver; n 1 represents the nonlinear coefficient in the braking torque mapping function. In this embodiment, n 1 = 1.3, and a value greater than 1 indicates that it belongs to the amplification effect of pedal force. The term, as a special position factor, is used to ensure the braking intensity and the real-time pedal opening. i Related, i When the value is 0, this item is 1 to provide maximum braking; i When the value is 30%, this item is 0, and the braking is minimal.

[0082] Analysis of the torque mapping in the braking zone of this embodiment reveals that it closely matches users' actual operating habits. For example, in daily driving, drivers typically use a small pedal force to make minor speed adjustments, at which point the system provides a response with good linearity. In emergency situations, however, drivers will instinctively release the pedal forcefully, at which point the nonlinear amplification effect can quickly provide maximum braking force, shorten the braking distance, and improve safety.

[0083] In the drive zone, the torque mapping design takes into account the pedal force saturation characteristics; the greater the pedal opening (the deeper the pedal is pressed), the stronger the drive torque. Therefore, the output drive torque... T drive Satisfy the following formula:

[0084] ;

[0085] In the above formula, K drive This is the maximum driving torque; in this embodiment, K drive =500N•m to fully utilize the motor's power performance. F refd For reference driving force; in this embodiment, F refd Slightly higher than the braking reference force, F refd =100N•m. n 2 represents the nonlinear coefficient in the drive torque mapping function; in this embodiment, it is set... n 2=0.8 to prevent the torque from being too sensitive to the pedal force during deep drive. Similarly, it is included as a positional influence term in the drive torque mapping function to ensure that the more the pedal is pressed, the greater the drive torque that the motor can provide.

[0086] Analysis of the torque mapping set in the drive zone shows that during start-up and low-speed acceleration ( i Approximately 35%), even small changes in pedal force can produce a noticeable torque response, facilitating precise control; while during high-speed cruising or when continuous acceleration is required ( i With torque primarily determined by pedal position (approximately 100%), the driver doesn't need to exert continuous force, reducing fatigue. Simultaneously, the design provides maximum driving force when the pedal is fully released, aligning with the driver's instinctive reaction to quickly release the pedal when rapid acceleration is needed, resulting in a more natural and fluid driving experience.

[0087] Finally, a linear transition strategy is employed in the buffer zone to minimize torque abrupt changes, providing a smooth driving experience and outputting buffered torque. T buf for:

[0088]

[0089] In the above formula, x It serves as a transition factor to ensure a smooth torque transition, completing the shift from braking to driving within 5% of the pedal travel. d This represents the driving force influence coefficient, which controls the degree to which the driver's pedal force contributes to the final output torque. L Indicates an equivalent arm. d and L The value of is chosen to ensure that the buffer zone does not generate significant driving or braking torque, thereby eliminating the abruptness caused by direct switching between braking and driving, and providing the driver with a smooth transition experience.

[0090] Analyzing the above formula, we can find that, due to T brake (30%) ≈ 0 (braking zone boundary) and T brake (35%) ≈ 0 (drive zone boundary), therefore the buffer zone basically does not generate significant drive or braking torque. The buffer zone set in this embodiment solves a key problem in the integrated drive and brake control: how to achieve a feeling similar to "coasting in neutral" in a traditional vehicle on a single pedal. The torque mapping of the buffer zone minimizes the influence of force, allowing the driver to easily keep the pedal in this range, achieving inertial coasting of the vehicle.

[0091] Example 2

[0092] Based on the three-segment electronic pedal provided in Embodiment 1, this embodiment further provides a vehicle control method based on a drive-brake integrated control model, which is applied to vehicles using the electronic pedal as in Embodiment 1, and includes the following steps:

[0093] S1: Real-time acquisition of pedal opening degree i And calculate the angular velocity of the pedal. .

[0094] This step is the foundational data acquisition stage of the entire control strategy. The accuracy and response speed of the pedal opening sensor directly affect the accuracy of all subsequent calculations. In practical applications, this embodiment can determine the real-time pedal opening by using the pedal position signal acquired in real time by the integrated opening sensor in the electronic pedal. iThe rate of change of pedal opening is obtained by differentiating the pedal position signal with respect to time. .

[0095] In practical applications, to ensure signal reliability, a redundant design can be adopted, installing multiple sensors of the same type for data comparison and verification. When performing derivative calculations on the pedal opening signal, since the original signal may contain high-frequency noise, low-pass filtering preprocessing is required to obtain a smooth and accurate opening change rate signal, providing high-quality input data for subsequent pedal force estimation.

[0096] S2: According to i Identify the current pedal travel range and combine it with the mechanical balance equations. i and Calculate the pedal force applied by the driver F driver :

[0097] ;

[0098] In the above formula, F driver The pedal force applied to the driver; F inertia The force is due to the inertia of the pedal. F spring ( i The spring restoring force of the pedal is denoted as . This refers to the damping force of the pedal. This refers to the friction force of the pedal.

[0099] In this embodiment, based on the constructed mechanical balance equation of the pedal, the real-time pedal opening and angular velocity can be used as inputs to estimate the pedal force applied by the driver. F driver However, considering that the signals acquired by the sensors may contain measurement noise and system delays, the noise will be amplified when differentiating the position signal to obtain the angular velocity and angular acceleration signals, thus affecting the estimated pedal force. F driver The error is too large. To solve this problem, this embodiment chooses to filter out high-frequency noise using a low-pass filter to reduce the error in the calculated pedal force. Specifically, in step S2, a first-order low-pass filter is used to filter the calculated pedal force according to... i Calculated pedal force F driver The filtering process is performed, and the corresponding filtering formula is as follows:

[0100] ;

[0101] In the above formula, s Represents the Laplace operator; This indicates the pedal force after filtering and correction. The filtering time constant is the parameter that needs to be selected, requiring a trade-off between filtering effectiveness and system response speed. An excessively large time constant will lead to system response delays, affecting the driving experience; an excessively small time constant will fail to effectively filter out noise. Based on system requirements, an experimental calibration was performed, resulting in a value of 0.05 to ensure effective filtering of measurement noise while maintaining good dynamic response characteristics.

[0102] S3: Vehicle speed relative to wheels v acceleration a slip ratio l and actual motor torque T ac Discrete sampling is performed to obtain the current state of the vehicle. x , And predict the next state of the vehicle based on the vehicle's dynamics model.

[0103] In practical applications, the discretization of the state should employ an appropriate sampling time, typically 0.01 seconds, to balance computational accuracy and real-time requirements. In this embodiment, the constructed vehicle dynamics model is used to accurately describe the vehicle's longitudinal dynamic characteristics while maintaining appropriate simplification to ensure the feasibility of real-time computation. In practical applications, its expression is as follows;

[0104] ;

[0105] In the above formula, x [ k ]and x [ k +1] represent the vehicle's current time. k and the next moment k +1 to the state variable; u [ k [] represents the control variables input to the vehicle at the current moment; A , B These represent the influence weight matrices for state variables and control variables, respectively. y [ k [] represents the controlled variable being output at the current moment; C This represents the state transition matrix between the state variables and the controlled variables. Matrices A, B, and C can be obtained through vehicle parameter identification and system modeling in practical applications. The determination of the above system matrices needs to consider parameters such as vehicle mass, tire radius, transmission ratio, and road adhesion coefficient, and is verified and corrected through real vehicle tests.

[0106] S4: According to i Generate a target torque for driving or braking the vehicle and use it as the torque demand at the current moment.y m [ k Then, the preset cost function is applied in conjunction with the vehicle's state. J (Δ u [ k The optimization solution is then performed to obtain the optimal torque change that satisfies the constraints and minimizes the cost function. sequence:

[0107] ;

[0108] In the above formula, express k Time prediction k + i Vehicle number at the moment j Real-time torque at each wheel. Indicates that the vehicle is in k + i The first moment j Target torque at each wheel; Δ u [ k ]and They represent k Time and k + i The change in torque at any given time; q j Indicates the first j Weighting coefficients of the state terms at each wheel; r Indicates the weighting coefficient of the control item; N p Indicates the observation step size; N c This indicates the control step size.

[0109] In this embodiment, the constraints are set to ensure that the system operates within safe boundaries. Specifically, based on the physical limitations of the actuator, the constraints that need to be satisfied in the optimization solution of the control commands in this embodiment include:

[0110] 1. Torque constraint: -300 N•m ≤ T cmd ≤500N•m.

[0111] In the above formula, T cmd These represent the ideal output motor torque of the vehicle; -300 N•m and 500 N•m correspond to the maximum braking torque and maximum driving torque, respectively. Of course, in practical applications, these two limits can be flexibly adjusted according to the motor characteristics, battery power, and thermal management system performance of the vehicle's actual motor.

[0112] 2. Torque change rate constraint: |ΔT cmd |≤Δ T max .

[0113] In the above formula, Δ T cmd This represents the rate of torque change, which is dynamically adjusted according to the control range to limit the speed of torque change, protect the transmission system, and improve comfort; Δ T max This indicates the maximum preset torque variation.

[0114] 3. Slip ratio constraint: l ≤0.2.

[0115] In the above formula, l This represents the vehicle's slip ratio. Setting a slip ratio constraint can prevent excessive wheel slippage, ensuring vehicle stability and effective utilization of tire adhesion. The limit of 0.2 is primarily determined based on the tire characteristic curve; in practical applications, this value can be further adjusted according to actual operating conditions.

[0116] 4. State constraints: Vehicle speed constraint 0≤ v ≤ v max Acceleration constraints | a |≤ a max .

[0117] In the above formula, v Indicates vehicle speed. v max This indicates the preset maximum vehicle speed; a This represents the longitudinal acceleration of the vehicle. a max This represents the maximum preset longitudinal acceleration of the vehicle. The two constraints described above are used to ensure that the vehicle operates within a reasonable range.

[0118] S5: Based on the optimal torque change at the current moment in the sequence. The system issues torque adjustment commands to the vehicle to adjust its output torque.

[0119] S6: Repeat steps S1-S5 at each subsequent sampling time, dynamically adjust the torque adjustment command according to the new vehicle status and the pedal force input by the user, so that the real-time torque output by the vehicle can follow the torque demand.

[0120] The dynamic optimization method for model vehicle torque adjustment commands described above in this embodiment actually employs an advanced strategy based on Model Predictive Control (MPC), which can achieve multi-objective optimization control while satisfying various constraints. This embodiment introduces MPC into the drive-braking integrated control system, which not only accurately tracks the driver's torque demand but also comprehensively considers multiple requirements such as vehicle safety, comfort, and energy efficiency.

[0121] To make the control strategy clearer, the following provides a detailed introduction to the solution model and solution process of the optimization problem based on model predictive control used in the scheme:

[0122] In this embodiment, to simplify the problem, it is assumed that the vehicle to be controlled meets the following conditions: (1) The vehicle always travels in a straight line, and lateral and vertical forces are not considered; only longitudinal forces are considered. (2) It is assumed that the road in the simulation test has no slope. (3) The left and right sides of the vehicle are completely symmetrical, and the braking and driving of the vehicle are completely controlled by the torque of the rear axle motor. (4) There is a linear relationship between the longitudinal ground torque and the longitudinal ground force. Under these conditions, a state-space model of the vehicle's longitudinal dynamics is established. This model needs to accurately describe the dynamic characteristics of the vehicle while maintaining appropriate simplification to ensure the feasibility of real-time calculation.

[0123] First, the state-space equation for vehicle speed is constructed as follows:

[0124] ;

[0125] In the above formula, for v The first derivative, which is the longitudinal acceleration of the vehicle. a .

[0126] For the overall force analysis of the vehicle during driving (ignoring the slope), the following can be obtained from the vehicle's driving equation:

[0127] ,

[0128] ,

[0129] In the above formula, F t Indicates the driving force; F f Indicates rolling resistance; F w Indicates air resistance; F i This represents slope resistance (set to 0 here, ignoring slope). F j Indicates acceleration resistance;T ac This represents the actual motor torque. i 0 is the transmission ratio of the main reducer; or t For transmission efficiency; r w Where G is the wheel radius; G represents the vehicle's weight. C D This refers to the air drag coefficient; r air density; S For windward area; d 0 represents the rotational mass conversion factor; m The total mass of the vehicle; d Represents the differential symbol. Indicates vehicle speed v right t Find the derivative, which is the vehicle acceleration; f This is the road surface friction coefficient.

[0130] Ignoring the rotational mass conversion factor, let d =1, the above expression can be simplified to:

[0131] ;

[0132] In the above formula, for a The first derivative; for T ac The first derivative.

[0133] Slip ratio can be divided into slip ratio during driving and slip ratio during braking. The slip ratio for rear-wheel drive can be expressed as... s t :

[0134] ;

[0135] In the above formula, oh This indicates the angular velocity of the wheel's rotation.

[0136] Rear wheel brake slip ratio s b It can be represented as:

[0137] ;

[0138] Differentiating both sides of the above equation and simplifying it, we get:

[0139] ;

[0140] In the above formula, and They are respectively st and s b The first derivative.

[0141] By analyzing the forces acting on the rear wheel separately, the torque balance equation for the rear wheel is derived as follows:

[0142] ;

[0143] In the above formula, express oh The first derivative; T t This refers to the braking torque acting on the wheels; F x The ground tangential reaction force, I This represents the moment of inertia of the rear wheel.

[0144] Among them, the actual motor torque T ac and T t The following conversion relationships exist:

[0145] ;

[0146] Substituting it into the previous equation, we get:

[0147] ;

[0148] The dynamic change of motor torque follows certain dynamic laws. It changes in the direction of the motor torque command, but due to factors such as system inertia, it will not instantly reach the commanded torque value. This process can be approximated as a first-order inertial element, and the specific formula is as follows:

[0149] ;

[0150] In the above formula, T cmd This is the instruction sent to the motor controller, i.e., the ideal output motor torque.

[0151] In summary, we have:

[0152] ;

[0153] Based on this, select vehicle speed v acceleration a slip ratio l Actual motor torque T ac If we consider the state variables, then the state-space equations of the vehicle are as follows:

[0154] ;

[0155] In the above formula, It is a state vector x ( t The first derivative of ) represents the state as a function of time. t The rate of change; u ( t ) indicates the control quantity; A c It is a state matrix that describes the dynamic relationships between state variables; B cu It is an input matrix that describes the effect of the input on the state; C c It is an output matrix that describes how state variables are mapped to the output; y c ( t ) is the output vector representing the measurable output of the system.

[0156] Discretizing the state-space equations yields the following formula:

[0157] ;

[0158] In the above formula, x [ k ]and x [ k+ 1] represents the vehicle at the current time. k and the next moment k +1 to the state variable; u [ k [] represents the control variables input to the vehicle at the current moment; A , B These represent the influence weight matrices for state variables and control variables, respectively. y [ k [] represents the controlled variable being output at the current moment; C This represents the state transition matrix between the state variables and the controlled variables.

[0159] Considering only the vehicle's motion under braking conditions, the discrete state-space equations can be written as:

[0160] ;

[0161] In the above formula, x 1[ k ]~ x 4[ k These are the state variables. x 1~ x 4 in k The value at time, x 1[ k+ 1]~x 4[ k+ 1] are state variables x 1~ x 4 in k+ The value at time 1.

[0162] Set the prediction step size to N p Control step size is N c And establish a linear model to predict the cost function of the controller at the current time. J The expression is as follows:

[0163] ;

[0164] In the above formula, and r These are the weighting coefficients for each control objective; express k Predicted k + i Predicted velocity value at any given time; express k + i Expected speed reference value at any given time; express k Predicted k + i Predicted acceleration values ​​at time 1; express k + i The expected acceleration reference value at any given time; express k Predicted k + i The predicted value of the rear wheel slip ratio at time t; express k + i Reference value for the expected rear wheel slip ratio at any given time; express k Predicted k + i The predicted value of the actual motor torque at any given time; express k + i Reference value for the actual expected motor torque at any given time; express k + i The change in rear axle braking torque at any given time.

[0165] Let the cost function J To minimize this, we can find the optimal value of the control input at the current moment:

[0166] ;

[0167] In the above formula, Δ U [ k ] represents the set of control variable increments obtained from the solution; They are respectively represented as k , k +1、 k + N c - The increment of the control variable at time 1; the first term is selected as the adjustment value.

[0168] Select prediction step size N p and control step size N c If the values ​​are both "1", then the linear model predictive control law formula for the integrated control of the drive and braking of a pure electric vehicle is obtained as follows:

[0169] ;

[0170] In the above formula, The optimal Δ at the current moment u [ k ].

[0171] Example 3

[0172] Based on the solutions in Embodiments 1 and 2, this embodiment further provides a vehicle that employs an electronic pedal as in Embodiment 1, and further includes a model prediction controller, such as... Figure 2 As shown, the model predictive controller consists of a pedal multi-information acquisition module, a driver pedal force estimation module, a control interval management module, an interval-based pedal force-torque mapping module, and a torque dynamic correction module. The model predictive controller employs the vehicle control method based on the drive-brake integrated control model as described in Example 2. It dynamically updates the torque adjustment command sent to the actuator based on the vehicle state of the pure electric vehicle and the user-input pedal force, thereby enabling the real-time torque output by the vehicle to follow the torque demand.

[0173] The model predictive controller in this embodiment is essentially a computer device. In practical applications, it can be an embedded device, which can directly update torque adjustment commands based on data collected from the front end. Alternatively, it can be a standalone computer device, such as a laptop, tablet, desktop computer, or a rack server, blade server, tower server, or cabinet server (including standalone servers or server clusters composed of multiple servers) capable of executing computer programs. This allows for the processing of signals output from the front-end vehicle, the updating of torque adjustment commands, and their transmission to the vehicle's control system.

[0174] The computer device in this embodiment includes, but is not limited to, a memory and a processor that can be interconnected via a system bus. In this embodiment, the memory (i.e., the readable storage medium) includes flash memory, hard disk, multimedia card, card-type memory (e.g., SD or DX memory), random access memory (RAM), static random access memory (SRAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), programmable read-only memory (PROM), magnetic memory, magnetic disk, optical disk, etc. In some embodiments, the memory can be an internal storage unit of the computer device, such as the hard disk or RAM of the computer device. In other embodiments, the memory can also be an external storage device of the computer device, such as a plug-in hard disk, smart media card (SMC), secure digital card (SD), flash card, etc. Of course, the memory can also include both internal storage units and external storage devices of the computer device. In this embodiment, the memory is typically used to store the operating system and various application software installed on the computer device. Furthermore, the memory can also be used to temporarily store various types of data that have been output or will be output.

[0175] In some embodiments, the processor may be a central processing unit (CPU), a controller, a microcontroller, a microprocessor, or other data processing chip. The processor is typically used to control the overall operation of a computer device.

[0176] Simulation test

[0177] To verify the performance of the electronic pedal and the vehicle control method based on the integrated drive and brake control model provided by this invention, technicians simulated the relevant schemes and tested their performance.

[0178] 1. Simulation conditions

[0179] This experiment selected a pure electric vehicle based on rear axle braking as the vehicle model for simulation. The specific basic parameters of the vehicle are shown in the table below:

[0180] Table 1: Basic parameters of the simulation process

[0181]

[0182] 2. Control process simulation

[0183] This experiment first simulates the cyclical operating conditions of a pure electric vehicle in urban environments, characterized by frequent start-stop cycles and continuous speed variations within a low-to-medium speed range. The driver can adjust the pressure and rate at which they press and release the pedal as the initial pedal signal input to begin the simulation. At this point, the initial velocity of the pure electric vehicle is 0, and the pedal position is also at zero.

[0184] During the experiment, the pedal opening value and the rate of change of opening corresponding to the simulated working conditions are shown in the attached figure. Figure 3 As shown in the figure, analysis of the data reveals that:

[0185] During the driving phase, the vehicle is in driving mode when the pedal opening is between 35% and 100% of its travel. During these periods, the pedal opening undergoes multiple increases and decreases, meaning the vehicle performs multiple acceleration and deceleration operations. A larger rate of change at corresponding moments in the graph indicates high driving intensity and rapid vehicle acceleration; conversely, when the pedal opening decreases, the driving intensity weakens, and the vehicle accelerates more slowly or begins to decelerate.

[0186] During braking, the vehicle is in a braking state when the pedal opening is between 0% and 30% of its travel. Similarly, the rate of change of pedal opening reflects the braking intensity; a larger rate of change indicates stronger braking. For example, at certain times, a rapid decrease in pedal opening results in strong braking; conversely, a slow decrease in pedal opening indicates weaker braking.

[0187] During the buffer phase, the pedal opening varies within the 30%-35% travel range. Within this range, the pedal opening changes relatively smoothly. As can be seen from the two graphs, the pedal opening and rate of change fluctuate little during the corresponding time period, and the vehicle's power state transitions smoothly, without strong driving or braking.

[0188] Furthermore, the simulation process requires a motor torque mapping diagram as follows: Figure 4 As shown in the figure, analysis of the data reveals that the pedal input signal, through the reverse calculation of pedal force, effectively reflects the integrated control logic of drive and braking. The pedal opening and its rate of change are closely related to the motor torque demanded by the driver. Changes in pedal opening directly determine the magnitude and direction of the demanded motor torque, thereby controlling the vehicle's drive or braking state.

[0189] 3. Tracking effect test

[0190] This experiment further plotted the tracking performance of vehicle speed, acceleration, and torque relative to the required values ​​during vehicle operation. The acceleration reference value was set to -1.962 m / s². 2 , to obtain Figure 5-Figure 7 The tracking curve.

[0191] Depend on Figure 5The vehicle speed simulation curves show that the actual vehicle speed follows the reference speed well. During acceleration, the actual vehicle speed quickly catches up with the reference speed, and during deceleration, it decreases smoothly and synchronously without significant lag or overshoot. Data shows a smooth speed transition without sudden speed changes caused by rapid acceleration or deceleration. In steady-state driving, the deviation between the actual and reference speeds is controlled within ±2 km / h, indicating a small error. Combined with model predictive control, the vehicle speed control achieves precise tracking of the reference trajectory through dynamic torque adjustment, effectively avoiding the speed fluctuation problems common in integrated drive and braking control modes. Overall performance is excellent, with high speed control accuracy and smooth response, meeting the fine-tuning requirements of urban driving conditions and improving driving comfort and controllability.

[0192] like Figure 6 In terms of acceleration response speed, the curve rapidly approaches the steady-state value in the initial stage; in terms of response characteristics, the actual acceleration rapidly approaches the reference value in the initial stage (0-0.2s), with rapid dynamic response and no obvious start-up delay; in the steady-state stage, the actual acceleration fluctuates slightly around the reference value, with the fluctuation range controlled within ±0.2m / s². 2 Within a certain range, the system exhibits excellent stability. Regarding error metrics, a steady-state average acceleration error of less than 5% indicates a fast system response and good performance of the model predictive controller for dynamic adjustment. From a steady-state performance perspective: the curve exhibits minimal fluctuations after stabilization, demonstrating high control accuracy in the steady-state phase, covering the dynamic processes of braking deceleration and driving acceleration.

[0193] analyze Figure 7 The data shows that, judging from the curve trend, the torque response can quickly follow changes in operating conditions. In the initial 0-20s period, the torque rapidly adjusts to the target range, and then maintains a relatively stable output under different operating conditions, without significant fluctuations or abrupt changes. Before 0.2 seconds, the rear axle motor torque increases from its initial value of 0. Due to braking conditions, the torque value is negative. Around 0.2 seconds, the torque gradually converges towards the optimal value of -220, with a fluctuation range of approximately 10 and an average error of 4.55%, demonstrating high control precision. Overall, the motor torque control effect is excellent, with rapid dynamic response, stable steady-state performance, and precise execution of torque adjustment commands, meeting the power output requirements of the integrated drive and braking control mode, resulting in good overall control performance.

[0194] Finally, it should be noted that this experiment presents the operating results under a typical simulation condition, but the solution is not limited to urban driving conditions. It also shows relatively ideal control results in the other two braking strategy ranges, such as the combined control of front axle mechanical braking and rear axle motor braking, and fully mechanical braking (emergency braking). Furthermore, the pedal opening and rate of change signals collected by the driver on the pedal in the braking intention fuzzy controller and braking intensity fuzzy controller can also be used to identify the driver's driving intention, and the fuzzy rule formulation method is also applicable to the control strategies of other types of vehicles with integrated drive and braking control.

[0195] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An electronic pedal, characterized in that, It includes: The pedal body has travel intervals of [0, 30%), [30%, 35%) and [35%, 100%), which serve as the braking zone, buffer zone and driving zone, respectively. An opening sensor is used to detect the real-time opening degree of the pedal along a preset travel distance. ; A feedback component, which is connected to the pedal body, and is used to provide feedback based on... The system outputs corresponding mechanical feedback to the pedal body; this includes: in the braking zone, the feedback component simulates the force-feel characteristics of a spring whose stiffness increases non-linearly as a quadratic function with respect to pedal opening; the simulated spring stiffness function is: ； In the above formula, k brake This represents the simulated spring stiffness; k b0 , k b1 and k b2 These represent the constant term, the coefficient of the first term, and the coefficient of the second term of the braking zone stiffness function, respectively. Spring restoring force output by the feedback component F spring as follows: ； In the above formula, This indicates the maximum opening of the braking zone; In the buffer, the feedback component simulates the force-feed characteristics of a soft spring with constant stiffness; the simulated spring stiffness function is: ； In the above formula, k 0 indicates the preset stiffness value of the buffer; Spring restoring force output by the feedback component F spring as follows: ； In the drive zone, the feedback component simulates the force feedback characteristic of a spring whose stiffness increases linearly with the pedal opening; and the initial stiffness of the drive zone is equal to the constant stiffness of the buffer zone to provide asymptotic force feedback; the simulated spring stiffness function is: ； In the above formula, The initial stiffness of the driving region; This represents the stiffness growth rate of the driving region; Spring restoring force output by the feedback component F spring as follows: ； Output component, which is used to determine the output based on the output component. Outputting a target torque to the vehicle control system for driving or braking the vehicle; including: outputting torque in the braking zone... Negatively correlated braking torque; output in buffer zone and A buffer torque that is related to and gradually converts from braking torque to driving torque; output in the driving region and The driving torque is positively correlated with the pedal force.

2. The electronic pedal as described in claim 1, characterized in that: In the braking zone, the output braking torque T brake Satisfy the following formula: ； In the above formula, K brake This is the maximum braking torque; F refb For reference braking force; F driver The pedal force applied to the driver; n 1 represents the nonlinear coefficient in the braking torque mapping function; In the drive region, the output drive torque T drive for: ； In the above formula, K drive This is the maximum driving torque; F refd As a reference driving force; n 2 represents the nonlinear coefficient in the drive torque mapping function; In the buffer, the output buffer torque T buf for: ； In the above formula, As a transition factor; Indicates the driving force influence coefficient; L Indicates an equivalent arm.

3. A vehicle control method based on a drive-braking integrated control model, characterized in that, It is applied to vehicles employing the electronic pedal as described in claim 1 or 2, and includes the following steps: S1: Real-time acquisition of pedal opening degree And calculate the rate of change of pedal opening. ; S2: According to Identify the current pedal travel range and combine it with the mechanical balance equations. and Calculate the pedal force applied by the driver F driver : ； In the above formula, F driver The pedal force applied to the driver; F inertia The force is due to the inertia of the pedal. The restoring force of the pedal spring; This refers to the damping force of the pedal. This refers to the friction force of the pedal. S3: Vehicle speed relative to wheels v acceleration a slip ratio and actual motor torque T ac Discrete sampling is performed to obtain the current state of the vehicle. x , And predict the next state of the vehicle based on the vehicle's dynamics model; S4: According to Generate a target torque for driving or braking the vehicle and use it as the torque demand at the current moment. y m [ k Then, the preset cost function is applied in conjunction with the vehicle's state. J (△ u [ k The optimization solution is then performed to obtain the optimal torque change that satisfies the constraints and minimizes the cost function. sequence: ； In the above formula, q 1. q 2. q 3. q 4 and r These are the weighting coefficients for each control objective; express k Predicted k + i Predicted velocity value at any given time; express k + i Expected speed reference value at any given time; express k Predicted k + i Predicted acceleration values ​​at time 1; express k + i The expected acceleration reference value at any given time; express k Predicted k + i The predicted value of the rear wheel slip ratio at time t; express k + i Reference value for the expected rear wheel slip ratio at any given time; express k Predicted k + i The predicted value of the actual motor torque at any given time; express k + i Reference value for the actual expected motor torque at any given time; express k + i The change in rear axle braking torque at any given time; S5: Based on the optimal torque change at the current moment in the sequence. Issue torque adjustment commands to the vehicle to adjust the vehicle's output torque; S6: Repeat steps S1-S5 at each subsequent sampling time, dynamically adjust the torque adjustment command according to the new vehicle status and the pedal force input by the user, so that the real-time torque output by the vehicle can follow the torque demand.

4. The vehicle control method based on the integrated drive and braking control model as described in claim 3, characterized in that: In step S2, the pedal damping force F damping The following nonlinear model is used for calculation: ； In the above formula, The basic damping coefficient; This is the location correlation coefficient; The velocity correlation coefficient; pedal friction F friction The following combined model of Coulomb friction and viscous friction is used for calculation: ； In the above formula, F c Coulomb friction; c v Coefficient of viscous friction; sign function To determine the direction of motion, ensure that the frictional force is always opposite to the direction of motion.

5. The vehicle control method based on the integrated drive and braking control model as described in claim 3, characterized in that, In step S3, the vehicle's dynamic model is as follows: ； In the above formula, x [ k ]and x [ k+ 1] represents the vehicle at the current time. k and the next moment k +1 to the state variable; u [ k [] represents the control variables input to the vehicle at the current moment; A , B These represent the influence weight matrices for state variables and control variables, respectively. y [ k [] represents the controlled variable being output at the current moment; C This represents the state transition matrix between the state variables and the controlled variables.

6. The vehicle control method based on the integrated drive and braking control model as described in claim 3, characterized in that: In step S1, the real-time opening degree of the pedal is measured by the opening degree sensor. Measurements are performed, and in step S2, a first-order low-pass filter is used to filter the data according to the given conditions. Calculated pedal force F driver The filtering process is performed, and the corresponding filtering formula is as follows: ； In the above formula, The filtering time constant; s Represents the Laplace operator; This represents the pedal force after filtering and correction.

7. A vehicle, characterized in that, It employs the electronic pedal as described in claim 1 or 2, and further includes a model predictive controller. The model predictive controller employs the vehicle control method based on the drive-brake integrated control model as described in any one of claims 3-6, to dynamically update the torque adjustment command according to the vehicle state and the pedal force input by the user, thereby enabling the real-time torque output by the vehicle to follow the torque demand.

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