Method and system for road feel enhancement based on driving profile assistance

Abstract

The present application relates to the technical field of vehicle control, in particular to a road feeling enhancement method and system based on driving road spectrum assistance, wherein the road feeling enhancement method comprises the following steps: obtaining stress signals of chassis leaf springs, air pressure signals of air springs, torsional vibration signals during operation of an engine and a transmission shaft, and vibration signals of a driver's cabin, forming a whole vehicle vibration representation quantity, forming a driving road spectrum by associating with a vehicle speed signal, generating vibration signals and torque signals for enhancing road feeling feedback in combination with a pre-labeled basic road spectrum and road condition history data; determining the demand for road feeling feedback according to a current vehicle speed signal, a steering torque of a steering wheel and a steering angle, and superimposing the pre-labeled basic assist characteristic and the obtained vibration signals and torque signals. The whole vehicle vibration representation quantity reflects driving habits, and the road feeling feedback is enhanced in combination with historical road condition data, so as to accurately reflect the load signal changes of a steering assist motor as much as possible.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of vehicle control, in particular to a road feeling enhancement method and system based on driving road spectrum assistance. BACKGROUND

[0002] The statements in this section merely provide background information related to the present application and do not necessarily constitute the prior art.

[0003] EPS (Electric Power Steering) is a vehicle steering technology that directly provides steering assistance using an electric motor. It replaces the traditional hydraulic power steering system (HPS) through electronic control, with the characteristics of higher efficiency, more flexible control and more environmental protection. Since the steering control demand is transmitted to the steering actuator in the form of pure electronic signals, the road excitation during vehicle driving cannot be directly transmitted to the steering wheel like traditional mechanical systems, making it difficult for the driver to perceive the road conditions through tactile feedback. To solve this problem, the EPS system generates real-time road excitation feedback through a road feeling simulation mechanism and transmits it to the steering wheel.

[0004] Currently, there are two main methods for road excitation simulation: parameter fitting and dynamic calculation. Parameter fitting method selects variables related to road feeling (such as steering wheel angle, vehicle speed, lateral acceleration, etc.) for fitting calculation, and then generates road feeling feedback. Dynamic calculation method establishes a dynamic model based on vehicle dynamics parameters (such as tire friction coefficient, lateral force, etc.), and estimates the tire return torque to achieve road feeling feedback.

[0005] The road feeling feedback of the EPS system is the result of the cooperation between electronic control and mechanical structure, and its core is to simulate the mechanical feedback of the traditional steering system by controlling the steering assistance motor to apply a reverse torque (or load). During vehicle manufacturing, a pre-calibration method is usually used to balance between "comfort" and "feedback". However, due to the differences in different road conditions and driving habits, the existing method cannot accurately reflect the changes in the load signal of the steering assistance motor, resulting in unsatisfactory road feeling feedback. SUMMARY

[0006] To solve the technical problems existing in the background art, the present application provides a road feeling enhancement method and system based on driving road spectrum assistance, which collects vehicle vibration characteristic data reflecting driving habits, generates driving road spectrum after processing, and dynamically generates vibration signals and torque signals for road feeling feedback by combining pre-calibrated basic road spectrum and road condition history data. This method can adaptively adjust the road feeling feedback strength according to different road conditions and driving habits, thereby improving the realism of the steering system and the driving experience.

[0007] In order to achieve the above object, the present application adopts the following technical solutions:

[0008] The first aspect of the present application provides a road feeling enhancement method based on driving road spectrum assistance, comprising the following steps:

[0009] The stress signal of the chassis leaf spring, the air pressure signal of the air spring, the torsional vibration signal during the operation of the engine and the transmission shaft, and the vibration signal of the cab are obtained to form a whole vehicle vibration representation quantity, and the driving road spectrum is formed by associating with the vehicle speed signal;

[0010] According to the obtained driving road spectrum, the vibration signal and the torque signal used for enhancing the road feeling feedback are generated in combination with the pre-labeled basic road spectrum and the road condition history data;

[0011] According to the current vehicle speed signal, the steering torque and the steering angle of the steering wheel, the demand for road feeling feedback is determined, and the pre-labeled basic assist characteristic is superimposed with the obtained vibration signal and torque signal to realize road feeling enhancement.

[0012] Further, the torsional vibration signal during the operation of the engine and the transmission shaft is obtained, including obtaining the frequency domain energy distribution of the torsional vibration by performing difference operation and fast Fourier transform on the acceleration signal, and obtaining the size of each vibration order of the torsional vibration in the frequency domain range relative to the speed of the current shaft system to form the torsional vibration signal.

[0013] Further, obtaining the torsional vibration signal during the operation of the engine and the transmission shaft further comprises, for the engine, taking the acceleration signal at the flywheel end as a reference and taking the acceleration signal at the shock absorber end as a comparison.

[0014] Further, obtaining the torsional vibration signal during the operation of the engine and the transmission shaft further comprises, for the transmission shaft, taking the acceleration signal at the axle end as a reference and taking the acceleration signal at the gearbox end as a comparison.

[0015] Further, the whole vehicle vibration representation quantity is associated with the vehicle speed signal to form the driving road spectrum, specifically: the obtained chassis leaf spring stress signal, air spring air pressure signal, engine and transmission shaft torsional vibration signal and cab vibration signal are weighted and processed, and associated with the corresponding vehicle speed signal to obtain the frequency spectrum data of the whole vehicle vibration representation quantity following the change of the vehicle speed.

[0016] The second aspect of the present application provides a road feeling enhancement system based on driving road spectrum assistance, comprising:

[0017] The driving habit analysis module is configured to obtain the stress signal of the chassis leaf spring, the air pressure signal of the air spring, the torsional vibration signal during the operation of the engine and the transmission shaft, and the vibration signal of the cab to form a whole vehicle vibration representation quantity, and form a driving road spectrum by associating with the vehicle speed signal;

[0018] a road feeling enhancement module configured to generate vibration signals and torque signals for enhancing road feeling feedback according to the driving road spectrum obtained by the driving habit analysis module, in combination with a pre-calibrated basic road spectrum and road condition history data;

[0019] a road feeling control module configured to determine the demand for road feeling feedback according to the current vehicle speed signal, the steering torque and the steering angle of the steering wheel, and to superimpose the vibration signals and torque signals output by the road feeling enhancement module on the pre-calibrated basic assist characteristic to achieve road feeling enhancement.

[0020] Further, there is also a steering controller for loading the driving habit analysis module and the road feeling enhancement module, the steering controller being in communication connection with the plurality of strain sensors, pressure sensors and acceleration sensors to obtain input signals.

[0021] Further, the steering controller is connected with the road feeling vibration exciter through the road feeling vibration excitation controller, and the road feeling vibration exciter is connected with the steering wheel, so as to output vibration signals simulating road feeling to the steering wheel through the road feeling vibration exciter.

[0022] Further, the steering controller is connected with the road feeling torque motor through the road feeling torque controller, and the road feeling torque motor is connected with the steering wheel, so as to output torque signals simulating road feeling to the steering wheel through the road feeling torque motor.

[0023] Further, the steering controller is in communication connection with the cloud server through the road feeling controller and the ECU, for transmitting data during road feeling feedback.

[0024] Compared with the prior art, the above one or more technical solutions have the following beneficial effects:

[0025] 1. The road spectrum is the frequency spectrum data of the dynamic characteristics such as vibration and force feedback generated by the interaction between the tire and the road during the driving of the vehicle, which is used to quantify the influence of different road conditions on the feedback of the steering wheel. The driving road spectrum obtained by collecting the whole vehicle vibration represents the driving habits of the driver under different road conditions, and the vibration signals and torque signals for road feeling feedback are generated by combining the pre-calibrated basic road spectrum and road condition history data. The strength of road feeling feedback can be dynamically adjusted according to different road conditions and different driving habits of drivers, so as to improve the accuracy of feedback and the driving experience.

[0026] 2. The change of chassis spring stress and air spring pressure directly reflects the vehicle dynamic load and the road bump degree, and indirectly reflects the driving habit (such as intense driving or smooth driving). The torsional vibration signal of the engine and the transmission shaft reflects the periodic angular vibration in the torque transmission process. For example, when the driver accelerates sharply (the throttle opening increases rapidly in a short time) or the vehicle acceleration changes suddenly, the torsional vibration signal amplitude increases significantly. By comprehensively analyzing the suspension system stress and shaft torsional vibration data, the driving style can be more accurately identified, and the road feel feedback strategy can be optimized accordingly to achieve a dynamic balance between handling and comfort.

[0027] 3. Combined with historical road condition data and real-time collected data, it has self-learning ability, can continuously optimize the driving strategy for automatic transmission vehicles, and improve the economy and emission performance. In addition, in special road sections (such as accident-prone areas or bumpy roads), the system can actively enhance the road feel feedback strength to remind the driver to pay attention to the road conditions or correct the fatigue driving behavior. Compared with traditional visual / auditory alarms, this tactile feedback is more in line with human engineering and can more effectively guide safe driving. BRIEF DESCRIPTION OF DRAWINGS

[0028] The drawings accompanying the specification of this application form a part thereof, serve to further provide a further understanding of the application, and together with the description of the exemplary embodiments of the application, serve to explain the application, and do not constitute an improper limitation of the application.

[0029] Figure 1 is a whole process schematic diagram of the road feel enhancement method based on driving road spectrum assistance provided by one or more embodiments of the application;

[0030] Figure 2 is a whole architecture schematic diagram of the road feel enhancement system based on driving road spectrum assistance provided by one or more embodiments of the application;

[0031] Figure 3 is a schematic diagram of the basic structure of a vehicle provided by one or more embodiments of the application;

[0032] Figure 4 is a schematic diagram of the relationship between amplitude and time provided by one or more embodiments of the application;

[0033] Figure 5 is a schematic diagram of the relationship between amplitude and time provided by one or more embodiments of the application;

[0034] Figure 6 is a schematic diagram of the relationship between vehicle speed and vibration representation provided by one or more embodiments of the application;

[0035] Figure 7 is a schematic diagram of the structure of the driving habit analysis module provided by one or more embodiments of the application;

[0036] Figure 8 is a structural schematic diagram of an auxiliary road feeling enhancement module provided by one or more embodiments of the present application;

[0037] Figure 9 is a structural schematic diagram of a road feeling enhancement system based on driving road spectrum assistance provided by one or more embodiments of the present application.

[0038] In the figure: 1, cab, 2, engine, 3, flywheel, 4, gearbox, 5, drive shaft, 6, chassis, 7, leaf spring, 8, wheel, 9, air spring, 10, shock absorber. DETAILED DESCRIPTION

[0039] The present application will be further described below in conjunction with the accompanying drawings and embodiments.

[0040] It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs.

[0041] Terminology:

[0042] "Road spectrum" refers to the frequency spectrum data of the dynamic characteristics such as vibration and force feedback generated by the interaction between the tire and the road surface during vehicle driving. It is used to quantify the influence of different road conditions (such as asphalt, gravel, and deceleration strip) on the steering wheel feedback, and is a key reference basis for the EPS system to realize realistic road feeling.

[0043] The road feeling enhancement method and system based on driving road spectrum assistance given in the following embodiments, by monitoring the vehicle vibration parameters, obtaining the whole vehicle vibration representation capable of reflecting the driving habits, after a series of analysis and processing, forming the driving road spectrum, combining the pre-calibrated basic road spectrum and road condition history data, generating the parameters of auxiliary torque control, converting into vibration signals and torque signals for road feeling feedback enhancement.

[0044] Embodiment I:

[0045] As shown in Figure 1 , the road feeling enhancement method based on driving road spectrum assistance includes the following steps:

[0046] Obtaining the stress signal of the chassis leaf spring, the air pressure signal of the air spring, the torsional vibration signal during the operation of the engine and the drive shaft, and the vibration signal of the cab, forming the whole vehicle vibration representation, and forming the driving road spectrum by associating with the vehicle speed signal;

[0047] According to the obtained driving road spectrum, combining the pre-calibrated basic road spectrum and road condition history data, generating the vibration signals and torque signals for enhancing the road feeling feedback;

[0048] According to the current vehicle speed signal, the steering torque and the steering angle of the steering wheel, the demand of the road feel feedback is determined, the basic assist characteristic is superimposed with the obtained vibration signal and the torque signal to realize the road feel enhancement.

[0049] As a further embodiment, the torsional vibration signal during the operation of the engine and the transmission shaft is obtained, including obtaining the frequency domain energy distribution of the torsional vibration by differentiating the acceleration signal and performing fast Fourier transform, and obtaining the size of each vibration order of the torsional vibration in the frequency domain range relative to the speed of the current shaft system to form the torsional vibration signal.

[0050] As a further embodiment, the torsional vibration signal during the operation of the engine and the transmission shaft is obtained, and further includes, for the engine, taking the acceleration signal at the flywheel end as a reference and the acceleration signal at the shock absorber end as a contrast.

[0051] As a further embodiment, the torsional vibration signal during the operation of the engine and the transmission shaft is obtained, and further includes, for the transmission shaft, taking the acceleration signal at the axle end as a reference and the acceleration signal at the gearbox end as a contrast.

[0052] As a further embodiment, the vehicle vibration characteristic quantity is associated with the vehicle speed signal to form a driving road spectrum, specifically: the obtained chassis leaf spring stress signal, the air spring air pressure signal, the torsional vibration signal of the engine and the transmission shaft and the vibration signal of the cab are weighted and processed, and are associated with the corresponding vehicle speed signal to obtain the frequency spectrum data of the vehicle vibration characteristic quantity following the change of the vehicle speed.

[0053] By collecting the vehicle vibration characteristic data reflecting the driving habit, the driving road spectrum is generated after processing, and the vibration signal and the torque signal for the road feel feedback are dynamically generated by combining the pre-calibrated basic road spectrum and the road condition history data. The method can adaptively adjust the road feel feedback strength according to different road conditions and driving habits, so as to improve the reality and driving experience of the steering system.

[0054] Embodiment two:

[0055] As Figure 2 shown, the road feel enhancement system assisted based on the driving road spectrum includes a driving habit analysis module and a road feel enhancement module. The road feel enhancement module generates the parameters of the auxiliary torque control according to the driving road spectrum obtained by the driving habit analysis module, combines the pre-calibrated basic road spectrum and the road condition history data, sends the parameters to the road feel controller, and outputs through the road feel driving motor.

[0056] The driving habit analysis module analyzes the driving habits and intensity of the driver by monitoring the vehicle vibration parameters, using predefined calculation logic and models, optimizes the control of the gearbox strategy and components such as suspension, realizes the adjustment of economy, emission, comfort, and conducts driving habit portrait, thereby providing analysis data for vehicle maintenance, insurance, safety warning, vehicle maintenance, etc.

[0057] The monitored vehicle vibration parameters are: chassis leaf spring stress, relative change value of air spring internal air pressure, engine instantaneous torsional vibration, transmission shaft instantaneous torsional vibration and cab vibration.

[0058] In combination Figure 3 The vehicle basic structure shown in the figure is introduced, and the vehicle vibration parameters to be monitored in the present scheme are introduced. Figure 3 In the figure, the air spring 9 is arranged between the cab 1 and the chassis 6, the engine 2 is fixed on the chassis 6, the shock absorber 10 and the flywheel 3 are arranged on the engine 2, the flywheel 3 transmits the power of the engine 2 to the wheels 8 (rear wheels) through the transmission shaft 5, and the chassis 6 is provided with the leaf spring 7 at the bottom.

[0059] Chassis leaf spring stress. Vehicles generally use leaf springs as suspension and damping components. Leaf springs (also known as leaf springs) are a kind of suspension and damping components made of multiple layers of elastic metal sheets (usually spring steel) stacked together, used to bear the vertical load of the vehicle (such as vehicle body, cargo, passenger weight), and transmit the load to the frame or chassis. During this period, the impact energy generated by the road bumps is absorbed by the elastic deformation of the metal sheet.

[0060] Therefore, the stress change of the leaf spring directly reflects the dynamic vehicle weight and the degree of road bumping during driving. Combined with road spectrum information and bumping degree, the driving habits of the driver can be reflected to a certain extent. By arranging multiple strain sensors at different positions of the leaf spring, the stress change of the leaf spring is obtained.

[0061] Relative change value of air spring internal air pressure. Some vehicles use air springs as damping components, or use air springs as adjustment of vehicle height and weight between tires on the basis of using leaf springs. Air spring (also known as air bag spring) is a kind of suspension component that uses the elasticity of compressed air to support the weight of the vehicle, adjust the suspension height and improve the damping performance. By increasing or decreasing the air pressure in the air bag, the change of the vehicle load (such as passengers / cargo increase / decrease) is automatically compensated, the vehicle body height is kept stable, and "tail collapse" or insufficient ground clearance is avoided. And the elastic coefficient of the air spring changes dynamically with the air pressure, which can better filter high-frequency vibration (such as gravel road) and low-frequency shaking (such as deceleration zone), and the comfort is significantly improved compared with metal springs (leaf springs / coiled springs). By independently adjusting the air spring pressure of each wheel, the load transfer caused by roll, acceleration / braking is compensated, the tire grip is kept uniform, and single-sided wear is avoided.

[0062] Therefore, the relative pressure change of the air inside the air spring can also reflect the driving habits of the driver. When the vehicle air spring adjustment is completed, the internal static pressure is relatively constant, but after the vehicle bounces, the internal pressure fluctuates, and by adding a pressure sensor at the air inlet, the stress of the air spring during vehicle operation can be monitored in real time.

[0063] Torsional vibration refers to the periodic angular vibration in the direction of rotation of the shaft system (such as the crankshaft of the engine, the transmission shaft, the output shaft of the motor, etc.) when transmitting torque due to periodic torque fluctuations or external excitation.

[0064] Engine instantaneous torsional vibration. This parameter reflects the torsional vibration of the shaft system under different operating conditions. The original torsional vibration of each engine is generally collected under stable calibration conditions, and the instantaneous torsional vibration can reflect the driver's control process of the throttle opening to some extent.

[0065] Transmission shaft instantaneous torsional vibration. The instantaneous torsional vibration of the transmission shaft between the gearbox and the axle also reflects the driver's control of the acceleration and deceleration of the vehicle to some extent.

[0066] In this embodiment, the test method of torsional vibration is to measure the acceleration at both ends of the shaft system, and then to perform differential calculation on the acceleration, and then to perform fast Fourier transform to obtain the frequency energy distribution of the torsional vibration. According to the current speed of the shaft system, the size of each vibration order of the torsional vibration in the frequency domain range relative to the speed is obtained. By differentiating the acceleration at both ends of the shaft system, the overall amplitude error caused by rolling vibration can be effectively eliminated.

[0067] For engine instantaneous torsional vibration and transmission shaft instantaneous torsional vibration, a passive magneto-electric sensor is used as a detection sensor to detect the engine flywheel ring gear, engine free end shock absorber tooth disc, and transmission shaft tooth disc at both ends to obtain the engine instantaneous torsional vibration and transmission shaft instantaneous torsional vibration. Form flywheel ring gear sensor, shock absorber tooth disc sensor, transmission shaft gearbox side sensor and transmission shaft axle side sensor.

[0068] For the engine, the flywheel end is used as the reference signal, and the shock absorber end is used as the comparison signal.

[0069] For the transmission shaft, the axle end is used as the reference signal, and the gearbox end is used as the comparison signal.

[0070] When the driver steps on the accelerator (the change in throttle opening is too high within a set time period) or the acceleration changes significantly, the torsional amplitude of the comparison signal will increase.

[0071] In this embodiment, taking the engine torsional vibration as an example, the relationship between the amplitude and time presents a sine function graph, and the original data Figure 4 andFigure 5 As shown in Figure 4 The horizontal axis is time and the vertical axis is amplitude. Figure 5 The horizontal axis is order and the vertical axis is amplitude.

[0072] The cab vibration is obtained by a vibration sensor.

[0073] The relevant parameters are obtained by the above detection method to form real-time vehicle vibration representation.

[0074] The motion equation of the automobile multi-mass system is designed, the masses of the vehicle body, engine, transmission shaft and tire are M1, M2, M3 and M4 respectively, the vehicle body, engine and transmission shaft are integrated components with consistent motion, the displacement is Z1, the tire is a rotating rolling forward, the displacement is Z2, the spring stiffness of the leaf spring is K1, the air spring stiffness is K2, the tire stiffness is K3, the damping coefficient is C, and the road roughness is Q, then the motion equation is:

[0075] ;

[0076] ;

[0077] Among them, The first order derivative of displacement Z1 with respect to time, i.e. speed (Z2 is the same) The second order derivative of displacement Z1 with respect to time, i.e. acceleration.

[0078] The Fourier transform is taken on the equation, and the determinant is solved, and the solution of the motion equation, i.e. the displacement data of the vehicle body and the tire, is derived.

[0079] In the case of a certain vehicle body mass, the collected engine torsional vibration, transmission shaft vibration, leaf spring stress, air spring pressure change value and other parameters are weighted and fitted with the solution of the above motion equation to approximately obtain the vibration representation and the change relationship diagram of the vehicle speed as shown in Figure 6 With the increase of vehicle speed, the vibration representation shows an exponential change trend, and the higher the vehicle speed, the smaller the change of the vibration representation, which reflects the actual scene that the higher the vehicle speed, the smaller the vibration felt by the driver.

[0080] The chassis leaf spring stress signal, air spring pressure signal, engine and transmission shaft torsional vibration signal and cab vibration signal obtained by the driving habit analysis module are weighted and associated with the corresponding vehicle speed signal to obtain the frequency spectrum data of the vehicle vibration representation following the change of the vehicle speed, i.e. the driving road spectrum.

[0081] In this embodiment, a driver drives a vehicle on a road for one time, and generates a map-based representation of the road segment, i.e., a basic road profile. After a large number of drivers and vehicles pass through the road segment, different data generated by different drivers are classified to obtain different driving habit profile data according to different driving types. The final road profile of the specific driving habit of the current road segment can be determined by superimposing a plurality of road profiles of the same type.

[0082] As shown in Figure 7 , the driving habit analysis module includes a multi-way switch receiving signals of a plurality of strain sensors and pressure sensors, and a signal conditioning module receiving signals of a flywheel ring sensor, a shock absorber tooth disc sensor, a transmission shaft gearbox side sensor, and a transmission shaft axle side sensor. The multi-way switch and the signal conditioning module communicate with an MCU through corresponding ADCs (analog-to-digital converters). The MCU receives signals sent by each sensor and signals of a 9-axis gyroscope. The MCU communicates with an ECU through a CAN bus.

[0083] By switching the analog signals of a plurality of sensors, the analog signals are sent to an ADC for analog-to-digital conversion, and after conversion, the current instantaneous pressure value and strain value are obtained.

[0084] By signal conditioning, the sinusoidal signal of a magneto-electric sensor is conditioned into a standard CMOS square wave signal, which is sent to a high-speed ADC for collection. After data is sent to an MCU for pulse analysis, acceleration signals of an engine and a transmission shaft are obtained.

[0085] A light-weight analysis model is called to obtain corresponding driving habit data and optimal driving state prompt signals by using the current instantaneous pressure value, the strain value, and the acceleration signals of the engine and the transmission shaft. The signals are sent to the ECU through the CAN bus. The ECU can perform strategy adjustment and other work according to the data.

[0086] At the same time, the collected data is sent to the cloud through an antenna at regular intervals for storage and analysis, which is used for model training on the cloud or for developing control strategies for the specific vehicle.

[0087] An auxiliary road feeling enhancement module receives driving profiles output from the driving habit analysis module, combines pre-calibrated basic road profiles and road condition history data to generate parameters for auxiliary torque control, and converts the parameters into vibration signals and torque signals for road feeling feedback enhancement. By controlling the motor of the steering wheel shaft, steering road feeling simulation is realized. By controlling the vibration exciter to generate vibration, road surface vibration road feeling simulation is realized.

[0088] As shown in Figure 8As shown, the signals obtained by the torque sensor, the vehicle speed sensor, and the rotation angle sensor are taken as inputs, the driving habit analysis module outputs the characteristic signals of the driving road spectrum, the basic assist characteristic (previously calibrated) is superimposed, the simulated vibration (for example, the "click" feeling when passing the road joint) is generated through the motor or the exciter, and the actual output torque of the motor is monitored to ensure consistency with the target value, thereby realizing the basic assist control, the return control, the compensation control, the damping control, and other functions. The motor refers to the steering assist motor in the EPS.

[0089] Regarding "superimposition of the characteristic signals of the driving road spectrum and the basic assist characteristic", for the rotation angle control of the steering wheel, mainly refers to the algebra and superposition of parameters such as damping size and rotation vibration intensity; for vibration, generally refers to the axial vibration of the steering wheel, which is added to the steering wheel shaft through the axial vibration excitation controller.

[0090] In this embodiment, the torque sensor is used to obtain the steering force of the driver, and the intention (such as sharp steering or fine adjustment) is judged. The vehicle speed sensor is used to reduce the assist force at high speed and enhance the stability; the assist force is increased at low speed. The rotation angle sensor is used to monitor the position of the steering wheel for return control.

[0091] In this embodiment, the basic assist control, the return control, the compensation control, the damping control, and other functions are realized by using the existing technology, and the present scheme only optimizes the superimposed road feeling part on the steering wheel based on the above driving process.

[0092] Return control: damping adjustment when the steering wheel automatically returns to the center.

[0093] Compensation control: offset external interference (such as crosswind, road inclination).

[0094] Damping control: suppress the shaking of the steering wheel (such as high-frequency vibration when passing through the deceleration zone).

[0095] Among them, the sensors and other inputs include road impact monitoring, inclination monitoring, crosswind detection, and the characteristic signals of the driving road spectrum output by the driving habit analysis module. The characteristic signals exist in the form of leaf spring or air spring, engine torsional vibration, main shaft torsional vibration, and the like. For electric vehicles, the motor acceleration is increased.

[0096] As shown in Figure 9 , the system architecture can be divided into two parts: the vehicle end and the cloud end.

[0097] The vehicle end part adds an auxiliary road feeling enhancement module in the steering controller of the vehicle, and the road feeling vibration excitation controller, the road feeling vibration exciter, the road feeling controller, and other components in communication connection with the steering controller.

[0098] The auxiliary road feeling enhancement module and the general road feeling control module form Figure 2The road feeling enhancement module is loaded into the steering controller together with the steering execution function module, and the steering controller sends a steering control instruction to the steering motor through the motor controller according to the steering angle feedback and the torque feedback, during which the auxiliary road feeling enhancement module and the general road feeling control module generate a vibration signal and a torque signal simulating road feeling.

[0099] The auxiliary road feeling enhancement module acquires engine torsional vibration, main shaft torsional vibration, leaf spring vibration signal, air spring vibration signal, road impact, lateral wind speed and vehicle inclination, and obtains road feeling control parameters after superposition with basic assistance characteristics through processing, sends an auxiliary road feeling torque control instruction and a vibration instruction simulating road feeling to the road feeling vibration exciter through the road feeling vibration excitation controller, the auxiliary road feeling torque control instruction is sent to the road feeling torque motor through the road feeling torque controller to realize road feeling torque simulation (such as changing resistance when steering); the vibration instruction simulating road feeling is sent to the road feeling vibration exciter through the road feeling vibration excitation controller, and the generated vibration is transmitted to the steering wheel to realize road feeling vibration simulation.

[0100] The auxiliary road feeling enhancement module generates signals for controlling the road feeling torque motor and the road feeling vibration exciter, and combines current road condition history data obtained from the ECU by the road feeling controller, fuses road spectrum and other information to generate comprehensive road feeling torque and vibration signal control information, and drives the actuator to generate simulated road feeling on the steering wheel.

[0101] The cloud receives driving road spectrum data, and realizes real-time update of the driving road spectrum according to the pre-stored basic road spectrum, road condition history data and received driving road spectrum through the road spectrum fusion algorithm, and communicates with the ECU through the Internet of Vehicles system.

[0102] The scheme realizes human-vehicle-road collaborative optimization through data-driven closed-loop control.

[0103] Through dynamic simulation of vibration signals and torque signals, the road feeling loss problem caused by the steer-by-wire system or the low-noise powertrain of the vehicle (such as the lack of engine vibration transmission of road information of an electric vehicle) is compensated, and the misoperation caused by the driver due to insufficient perception is avoided.

[0104] Driving habits are analyzed through suspension system stress and shaft torsional vibration, for example, the driver's preference for sports style is identified (judged by the leaf spring stress change rate), and the gearbox shift logic (the downshift timing is prolonged) and suspension damping (the stiffness is improved) are adjusted in linkage to realize dynamic balance of maneuverability and comfort.

[0105] For radical driving behavior (such as sudden acceleration / braking causes the transmission shaft torsional vibration to suddenly increase), the system can enhance the steering wheel damping or trigger a vibration warning, force to correct dangerous operation through tactile feedback, which is more ergonomic than visual / auditory warning, and the way of road feeling feedback has real-time, which can remind the driver to drive the vehicle better.

[0106] Combined with historical road condition data and real-time collected related data, the system has a self-learning function, which is beneficial to continuously optimize the strategy of automatic transmission vehicle (such as AT\AMT, etc.), so as to realize the optimal driving of economy and emission, and can improve the road feeling strength in special road sections, prompt the driver to pay attention to the accident-prone road section, or prompt the driver to fatigue driving, etc.

[0107] The above is only the preferred embodiment of the present application and is not used to limit the present application. For those skilled in the art, the present application can have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for road feel enhancement assisted based on driving profile, characterized in that, The method comprises the following steps: Obtaining stress signals of chassis leaf springs, air spring pressure signals, torsional vibration signals during engine and transmission shaft operation, and vibration signals of the cab, forming a vehicle vibration representation, and forming a driving road spectrum by associating with the vehicle speed signal; the vehicle vibration representation is associated with the vehicle speed signal to form the driving road spectrum, specifically: the obtained chassis leaf spring stress signals, air spring pressure signals, torsional vibration signals of the engine and transmission shaft, and vibration signals of the cab are processed by weighting, and are associated with the corresponding vehicle speed signal to obtain frequency spectrum data of the vehicle vibration representation changing with the vehicle speed; According to the obtained driving road spectrum, combined with the pre-labeled basic road spectrum and road condition history data, the vibration signal and torque signal for enhancing the road feeling feedback are generated; According to the current vehicle speed signal, the steering torque and the steering angle of the steering wheel, the demand of the road feeling feedback is determined, the pre-labeled basic assist characteristic is used, and the vibration signal and torque signal obtained are superimposed to realize the road feeling enhancement.

2. The road feel enhancement method based on driving road profile assistance of claim 1, wherein, The torsional vibration signal during the operation of the engine and the transmission shaft comprises: obtaining the frequency energy distribution of the torsional vibration by differentiating and performing fast Fourier transform on the acceleration signal, and obtaining the size of each vibration order of the torsional vibration in the frequency domain range relative to the speed of the current shaft system to form the torsional vibration signal.

3. The road feel enhancement method based on driving road profile assistance of claim 1, wherein, The torsional vibration signal during the operation of the engine and the transmission shaft further comprises: for the engine, taking the acceleration signal at the flywheel end as the reference and the acceleration signal at the shock absorber end as the comparison.

4. The road feel enhancement method based on driving road profile assistance of claim 1, wherein, The torsional vibration signal during the operation of the engine and the transmission shaft further comprises: for the transmission shaft, taking the acceleration signal at the axle end as the reference and the acceleration signal at the gearbox end as the comparison.

5. A road feel augmentation system assisted by a driving road profile, characterized by, The method comprises: The driving habit analysis module is configured to: obtain stress signals of chassis leaf springs, air spring pressure signals, torsional vibration signals during engine and transmission shaft operation, and vibration signals of the cab, form a vehicle vibration representation, and form a driving road spectrum by associating with the vehicle speed signal; the vehicle vibration representation is associated with the vehicle speed signal to form the driving road spectrum, specifically: the obtained chassis leaf spring stress signals, air spring pressure signals, torsional vibration signals of the engine and transmission shaft, and vibration signals of the cab are processed by weighting, and are associated with the corresponding vehicle speed signal to obtain frequency spectrum data of the vehicle vibration representation changing with the vehicle speed; The road feeling enhancement module is configured to: according to the driving road spectrum obtained by the driving habit analysis module, combined with the pre-labeled basic road spectrum and road condition history data, generate the vibration signal and torque signal for enhancing the road feeling feedback; The road feeling control module is configured to: according to the current vehicle speed signal, the steering torque and the steering angle of the steering wheel, determine the demand of the road feeling feedback, use the pre-labeled basic assist characteristic, and superimpose the vibration signal and torque signal output by the road feeling enhancement module to realize the road feeling enhancement.

6. The drive profile assistance based road feel enhancement system of claim 5, wherein, Further comprising a steering controller for loading the driving habit analysis module and the road feeling enhancement module, the steering controller is in communication connection with a plurality of strain sensors, pressure sensors and acceleration sensors to obtain input signals.

7. The drive profile assistance based road feel enhancement system of claim 6, wherein, The steering controller is connected with a road feel vibration exciter through a road feel vibration excitation controller, the road feel vibration exciter is connected with the steering wheel, and the road feel vibration excitation controller outputs a vibration signal simulating road feel to the steering wheel.

8. The drive profile assistance based road feel enhancement system of claim 6, wherein, The steering controller is connected with a road feel torque motor through a road feel torque controller, the road feel torque motor is connected with the steering wheel, and the road feel torque motor outputs a torque signal simulating road feel to the steering wheel.

9. The drive profile assistance based road feel enhancement system of claim 6, wherein, The steering controller is connected with a cloud server in communication through a road feel controller and an ECU, and is used for transmitting data during road feel feedback.

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