Electronic control unit and control method for electric power steering system of vehicle

Abstract

An electronic control unit for an electric power steering system of a vehicle is provided, including: an information acquisition block configured to receive a sensor signal related to electric power steering of the vehicle and determine a real-time front wheel steering angle of the vehicle based on the sensor signal; a steering decision block configured to determine a current driving mode of the vehicle based on the sensor signal and calculate a target control current to be provided using the real-time front wheel steering angle according to the determined current driving mode; and a current generation block configured to generate and output the target control current. Correspondingly, the invention further provides a control method for the electric power steering system of the vehicle.

Description

Technical Field

[0001] The present application generally relates to the field of vehicle steering control, and more particularly to an electronic control unit and a control method for implementing electric power steering control responsive to a vehicle driving mode based on a front wheel steering angle. Background Art

[0002] The design and development of steering control systems for vehicles, especially passenger cars, is an important aspect of achieving safe driving, comfortable driving, intelligent driving and even unmanned driving.

[0003] In the prior art, in the manned steering control mode equipped with Electric Power Steering (EPS) technology, the steering assist characteristic curve is widely used to determine the steering assist torque to be provided by the EPS motor. However, since the pre-set steering assist characteristic curve cannot reflect the transient steering resistance torque changes during the actual driving process of the vehicle, the control based on the steering assist characteristic curve often deviates from the immediate situation and causes control delay.

[0004] Intelligent driving technology based on EPS technology follows the steering wheel angle control strategy, and performs closed-loop angle tracking control through the deviation between the target steering wheel angle and the current steering wheel angle. However, in practice, due to various factors (such as changes in external environmental loads, changes in the load distribution inside the vehicle, and the influence of EPS control), there is nonlinearity in the transmission link from the steering wheel end to the front wheel end of the vehicle. In this case, simply calculating the steering wheel angle as the product of the front wheel angle and the steering system transmission ratio will produce errors and thus affect the accuracy of intelligent driving path planning and the effectiveness of the steering control algorithm. On the other hand, EPS control and intelligent steering control are often executed separately in two different electronic control units, resulting in problems such as excessive resource occupation and redundancy.

[0005] Therefore, it is desirable to provide an improved electronic control unit and control method for a vehicle electric power steering control system, which overcomes at least one of the above disadvantages. Summary of the invention

[0006] The present application proposes a steering control concept based on the vehicle's front wheel angle, which calculates the instantaneous vehicle steering resistance torque or the deviation from the target vehicle's front wheel angle based on the real-time detection or estimation of the vehicle's front wheel angle, and thereby calculates the target control current to be provided by the vehicle's EPS motor, thereby realizing intelligent electric power steering control of the vehicle.

[0007] According to one aspect of the present application, an electronic control unit for a vehicle electric power steering system is provided, comprising: an information acquisition block, the information acquisition block being configured to receive a sensor signal related to the electric power steering of the vehicle and determine the real-time front wheel steering angle of the vehicle based on the sensor signal; a steering decision block, the steering decision block being configured to determine the current driving mode of the vehicle based on the sensor signal and calculate a target control current to be provided using the real-time front wheel steering angle according to the determined current driving mode; and a current generation block, the current generation block being configured to generate and output the target control current.

[0008] Optionally, the information acquisition block comprises a front wheel steering angle estimation module, which is configured to determine the real-time front wheel steering angle of the vehicle based on detection of selected kinematic variables of a steering transmission mechanism directly connected to the front wheels of the vehicle.

[0009] Optionally, the steering transmission mechanism comprises a rack and pinion steering gear, and the selected kinematic variable is the displacement of the rack of the steering gear relative to the pinion.

[0010] Optionally, the information acquisition block is further configured to obtain the real-time front wheel steering angle of the vehicle from the detected value of the selected kinematic variable using a pre-stored functional relationship.

[0011] Optionally, the steering decision block includes a manned driving control module, which is configured to determine an immediate steering resistance torque based on the real-time front wheel angle and calculate a target control current to be provided based on the immediate steering resistance torque and detection information about hand torque in the sensor signal.

[0012] Optionally, the steering decision block includes an intelligent driving control module, and the intelligent driving control module is configured to calculate a target control current using a difference between the real-time front wheel steering angle and a target front wheel steering angle.

[0013] Optionally, the target front wheel turning angle is calculated based on a lateral path deviation and a yaw rate deviation.

[0014] Optionally, the steering decision block comprises a driving mode determination module, which is configured to determine a current driving mode of the vehicle based on detection information about pressure on a manual steering interface in the sensor signal.

[0015] Optionally, the driving mode determination module is configured to determine that the current driving mode of the vehicle is the intelligent driving mode based on the pressure on the manual steering interface being lower than a predetermined pressure threshold for more than a predetermined holding time threshold.

[0016] According to another aspect of the present application, a control method for a vehicle electric power steering system is provided, the method comprising: receiving a sensor signal related to the electric power steering of the vehicle, and determining a real-time front wheel steering angle of the vehicle based on the sensor signal; determining a current driving mode of the vehicle based on the sensor signal; calculating a target control current to be provided using the real-time front wheel steering angle according to the determined current driving mode; and generating and outputting the target control current.

[0017] Optionally, the control method is executed by the electronic control unit as described above. Various features described in this application with reference to the electronic control unit are also applicable to the control method of this application.

[0018] According to still another aspect of the present application, a machine-readable storage medium is provided, which stores executable instructions, and when the instructions are executed by a processor, the control method as described above is implemented.

[0019] According to the steering control disclosed in the present invention, the front wheel angle is used instead of the traditional steering wheel angle as the control parameter, which saves the angle conversion process, simplifies the algorithm logic and improves the control accuracy. For the manned driving mode, the calculation method based on the front wheel angle fundamentally avoids the nonlinear effect introduced by the control algorithm of the power-assist system in the steering transmission path from the steering wheel end to the front wheel end of the vehicle, and the real-time steering resistance torque calculated thereby is more accurate and reliable. For the intelligent driving mode, the front wheel angle can be advantageously directly combined with the target front wheel angle of the planned path to calculate the required steering motor control current, eliminating the intermediate link of converting to the steering wheel angle, which helps to enhance the timely responsiveness, sensitivity and accuracy of the control.

[0020] Using the front wheel angle as the steering control parameter is in line with the trend of EPS intelligent expansion, and promotes the deep integration of EPS technology and intelligent driving technology, so that a smooth transition and easy switching between manned driving mode and intelligent driving mode can be efficiently achieved with a simplified configuration structure and / or logical architecture. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Embodiments according to the principles of the present application are described in detail below in conjunction with the accompanying drawings. The accompanying drawings are provided in an exemplary manner to facilitate understanding of the specific embodiments described. However, the accompanying drawings are not intended to be limiting. Accordingly, any unclaimed feature shown in the accompanying drawings should not be interpreted as a necessary feature for implementing the principles of the present invention, and any claimed feature shown in the accompanying drawings should not be interpreted as the only way to implement the function related to the feature.

[0022] Figure 1 FIG. 4 is a schematic diagram of an exemplary structure of a vehicle steering system that can adopt the steering control concept based on the vehicle front wheel angle according to the principle of the present invention.

[0023] Figure 2 yes Figure 1 A schematic structural diagram of the interaction between the underlying steering transmission mechanism of a vehicle steering system including a steering gear, a tie rod and a steering knuckle arm and the front wheels of the vehicle.

[0024] Figure 3 FIG. 1 is a simplified diagram of an embodiment of a vehicle front wheel angle based steering control system according to the principles of the present invention.

[0025] Figure 4 is a flow chart illustrating an embodiment of a steering control method based on a vehicle front wheel angle according to the principles of the present invention. DETAILED DESCRIPTION

[0026] The basic concepts and principles of the present invention are described in detail below in conjunction with the preferred embodiments known to the inventors. It is understood that the following description is provided to make the present disclosure full and complete and to convey the spirit of the present invention to those skilled in the art. Accordingly, the description is only illustrative. After reading the following description, those skilled in the art will be able to modify, change and replace the disclosed embodiments as appropriate without departing from the spirit and teachings of the present invention.

[0027] The present invention mainly relates to vehicle steering systems, and accordingly, the positioning and orientation of related elements or features will be described mainly with the vehicle as the coordinate reference system, unless otherwise specified in the context. As used herein, relative spatial terms such as "front", "rear", "left", "right", "up", "down", "lateral", etc. and vehicle-related technical terms such as "(vehicle) front wheel angle", "steering wheel angle", "hand torque", "steering resistance torque", "electric steering torque", "lateral path deviation", "yaw rate deviation", "target front wheel angle", "target (motor) control current", etc. have the meanings commonly known to ordinary technicians in the field of vehicle engineering.

[0028] Figure 1 FIG. 1 is a schematic diagram of an exemplary structure of a vehicle steering system that can adopt the steering control concept based on the vehicle front wheel angle according to the principle of the present invention. Figure 1 As shown in FIG, the vehicle steering system 100 generally includes an upper driver control unit 10, a lower steering transmission unit (also referred to as a "steering transmission mechanism") 30, and an electric steering unit 20 disposed between the upper and lower layers. It should be noted that the "upper layer" and "lower layer" here refer to both the approximate vertical distribution position of the corresponding features in the vehicle and the level of the corresponding features in the entire steering transmission chain.

[0029] exist Figure 1In the example shown, the driver control unit 10 includes a generally circular steering wheel (also referred to as a "manual steering interface") 12 and an input shaft of a steering column 40 mechanically connected to the center of the steering wheel 12. The steering wheel 12 is installed in the cockpit of the vehicle for the driver seated in the cockpit to control the driving direction of the vehicle. The input shaft of the steering column 40 moves with the steering wheel 12, and the steering column 40 has an output shaft connected to the downstream components of the steering transmission chain. With the steering column 40, the hand torque applied by the driver when turning the steering wheel can be transmitted to the downstream of the steering transmission chain and finally transmitted to the front wheels of the vehicle. Although the figure shows a generally circular steering wheel 12 and a steering column 40, other forms of driver control units are also feasible. For example, the steering wheel 12 can have other shapes (e.g., non-circular), and / or the driver can indicate the desired driving direction in a manner other than turning the steering wheel (e.g., intelligent voice input). In addition, although the steering column 40 is illustrated, the system that can adopt the steering control principle of the present invention is not limited to a system with a steering column, but can also be applied to, for example, a wire control system.

[0030] The electronically controlled steering unit 20 can serve as a supplement to the driver control unit 10 in the manned driving mode to provide steering assist torque for vehicle steering; or the electronically controlled steering unit 20 can override the driver control unit 10 in the intelligent driving mode to plan a path for the vehicle and provide all the steering torque required for the corresponding steering.

[0031] exist Figure 1 In the example shown, the electric steering unit 20 generally includes: a torque angle sensor 22 mounted to the input shaft of a steering column 40, the torque angle sensor being configured to detect a steering wheel angle and a hand torque applied by a driver; an electronic control unit 24 being communicatively coupled to the torque angle sensor 22, the electronic control unit being configured to calculate the electric steering torque required in real time based on data received from an on-board sensor; a steering motor 26 for providing the electric steering torque required in real time, the steering motor being configured to be electrically coupled to the electronic control unit 24 to provide the electric steering torque based on a control current output by the electronic control unit 24 and to feed back corresponding motor operating parameters (e.g., motor operating current, motor output shaft speed, etc.) to the electronic control unit 24; and a reducer 28 connected to the output shaft of the steering column 40 and causing the electric steering torque to be applied to the steering column 40 in a suitable manner.

[0032] The electronic control unit 24 can communicate with a plurality of vehicle-mounted sensors to obtain relevant real-time information to calculate the electric steering torque required immediately. For example, the electronic control unit 24 can communicate with a sensor for detecting the vehicle's driving speed (such as Figure 1The electronic control unit 24 may be connected to a sensor (schematically shown by arrow 55 in the figure) to adjust the electric steering torque in response to changes in vehicle speed. The electronic control unit 24 may include one or more memories and one or more processors, wherein the one or more memories store instructions, and the instructions may be executed by the one or more processors to cause the electronic control unit 24 to output a target control current (sometimes also referred to as a "target motor control current") for causing the steering motor 26 to generate a desired electric steering torque.

[0033] The electric steering torque generated by the electric steering unit 20 and the hand torque generated by the driver's control unit 10 are transmitted to the steering transmission mechanism 30 disposed laterally between the left and right front wheels 50 of the vehicle through the steering column 40, and then transmitted to the front wheels of the vehicle via the steering transmission mechanism 30 to overcome the steering resistance torque on the front wheels of the vehicle to achieve front wheel steering. Figure 1 The speed reducer 28 is shown mounted to the steering column 40, however, the present invention is not limited thereto. The speed reducer 28 may also be mounted to other features besides the steering column in other examples, such as the steering transmission mechanism 30 described in further detail below.

[0034] The steering transmission mechanism 30 is as follows Figure 1 The steering gear 32 shown in FIG. 1 generally includes a rack and pinion steering gear 32, a tie rod 34 mechanically connected to the rack of the steering gear 32 on opposite sides of the steering gear 32, and a steering knuckle arm 36 mechanically connecting the tie rod 34 to the front wheels 50 of the vehicle. Figure 1 In the example of FIG. 4 , the steering gear 32 has a pinion gear mechanically connected to the other end of the steering column 40 opposite to the steering wheel 12 , and a rack gear cooperating with the pinion gear to convert a rotational motion into a translational motion in the lateral direction of the vehicle.

[0035] The steering transmission mechanism 30 forms an end effector for actuating the steering of the front wheels of the vehicle, and can more accurately reflect the instantaneous steering resistance torque experienced by the front wheels of the vehicle and the front wheel turning angle currently formed by the front wheels of the vehicle than the upper driver control unit 10 .

[0036] Figure 2 The interaction between the steering transmission mechanism 30 and the front wheel 50 of the vehicle is simply illustrated in the form of a structural schematic diagram, wherein the solid line diagram shows the spatial relative position relationship between the steering transmission mechanism 30 and the front wheel of the vehicle when the vehicle is traveling straight. To illustrate the interaction between the two, it is assumed that the left front wheel of the vehicle has a turning angle θ, for example, Figure 2As shown by the dotted line in FIG. 3 , the left steering knuckle arm 36 connected to the left front wheel of the vehicle will have a displacement in the direction of arrow 3, the left tie rod 34 connected to the left steering knuckle arm 36 will have a displacement in the direction of arrow 2, and the steering rack connected to the left tie rod 34 will have a displacement X in the direction of arrow 1. At the same time, the angles formed between the steering knuckle arm and the tie rod and between the tie rod and the steering rack will also change accordingly with the turning angle θ of the left front wheel of the vehicle. In other words, as the turning angle of the front wheel of the vehicle changes, the relative positional relationship of the various components of the steering transmission mechanism 30 will also change. Accordingly, the front wheel turning angle of the vehicle can be obtained by detecting the spatial state change of the steering transmission mechanism 30. Of course, the front wheel turning angle of the vehicle can also be obtained by other means, such as imaging the front wheel and measuring the change of the tire edge in the image, etc.

[0037] In one example, a simulation model of a vehicle steering system is established, and the relationship between the front wheel steering angle θ of the vehicle and the displacement X of the rack of the steering gear 32 of the steering transmission mechanism 30 relative to the pinion is obtained through numerical calculation and data fitting analysis. For example, the vehicle steering system can be modeled using simulation software, and then the rack displacement of the model steering system (i.e., the displacement of the rack relative to the pinion, hereinafter referred to as "rack displacement") is changed over time according to a predetermined displacement sequence X(t), and the corresponding front wheel steering angle sequence θ(t) is obtained. By performing data fitting on the displacement sequence X(t) and the front wheel steering angle sequence θ(t) in response to the displacement sequence, the fitting relationship between the front wheel steering angle and the rack displacement can be obtained: θ(t)=f'(X(t)). The relationship can be stored in a machine-readable manner in the memory of the electronic control unit 24 for offline use during vehicle driving. However, the relationship between the front wheel steering angle of the vehicle and the rack displacement can also be obtained in other ways. Alternatively, other kinematic variables can also be used to characterize the transient spatial state of the steering transmission mechanism 30.

[0038] The relationship between the vehicle front wheel steering angle and the selected variable can be pre-stored in the memory of the electronic control unit 24 before the vehicle leaves the factory, or the relationship can be downloaded from the server when the vehicle is started, etc. Based on the relationship between the front wheel steering angle and, for example, the rack displacement stored in the memory, the electronic control unit 24 can respond to the displacement sensor 60 (at the position of the steering gear 32) installed on the steering gear 32. Figure 1 The rack displacement signal received in real time is used to determine the target motor control current I to be output to the steering motor. tar .

[0039] Figure 3 FIG. 200 is a diagram showing an embodiment of a steering control system based on the front wheel angle of a vehicle according to the principles of the present invention. The steering control system 200 may be integrated into Figure 1The electronic control unit 20 and in particular the electronic control unit 24 of the electronic control unit 20 or as a part of the electronic control unit 24. Figure 3 As shown in , the steering control system 200 generally includes an information acquisition block 220 , a steering decision block 240 and a current generation block 260 .

[0040] The information acquisition block 220 is configured to receive sensor signals related to the electric power steering of the vehicle (for example, received from a vehicle-mounted sensor group electrically connected thereto or via a local area network) and convert the sensor signals into data that can be used for subsequent calculations. Figure 3 In the example of , the information acquisition block 220 is generally divided into two modules, namely the first module 220-1 and the second module 220-2, wherein the first module 220-1 receives a plurality of sensor signals from a first vehicle-mounted sensor group including a torque angle sensor 22 to determine the road information of the vehicle, the vehicle operation status information and the vehicle-road correlation information, and the second module 220-2 receives a detection signal for the rack displacement X from the displacement sensor 60 installed on the steering gear 32 to determine the front wheel angle of the vehicle. Accordingly, the second module 220-2 is sometimes also referred to as a front wheel angle estimation module. It is understood that the division of the first and second modules is only for the convenience of explanation, and is not intended to imply that the first and second modules are independent and / or completely unrelated modules. On the contrary, there may be data access, communication, calling and other docking between the first module and the second module, and the vehicle road information, vehicle operation status information, vehicle-road correlation information and vehicle front wheel angle data received, preliminarily processed and generated by the first module and the second module can be sent to the steering decision block 240 together in the form of a collection.

[0041] The steering decision block 240 is configured to determine a target motor control current to be output to the steering motor based on the information and data provided by the information acquisition block 220 and based on a predetermined algorithm. Figure 3 In the example, the steering decision block 240 includes a manned driving control module 240 - 1 , an intelligent driving control module 240 - 2 and a driving mode determination module 240 - 12 .

[0042] In the case of human driving, the target motor control current is aimed at enabling the driver to achieve the corresponding vehicle front wheel steering with the hand torque provided. Accordingly, the real-time vehicle front wheel steering angle data obtained directly or indirectly is used to calculate the instantaneous steering resistance torque of the vehicle front wheels, and then calculate the target motor control current corresponding to the electric steering torque to be provided by the steering motor.

[0043] In one example, the steering resistance torque M is calculated from the front wheel steering angle θ of the vehicle using the following algorithm: f ,Right now:

[0044] When the vehicle speed u=0,

[0045]

[0046] And when the vehicle speed u≠0,

[0047]

[0048] Among them, δ t is the ground contact deformation of the front tire of the vehicle, μ is the road friction coefficient, G1 is the front axle load, l t is the tire contact length, c is the kingpin offset, D is the tire diameter, φ is the kingpin inclination angle, M y is the self-aligning torque generated by the caster angle, M z is the self-aligning torque generated by the tire trail, u is the vehicle speed, and f(u) is the functional expression of the equivalent friction coefficient with respect to the vehicle speed u.

[0049] In another example, the following formula is used to calculate the steering resistance torque M: f Calculate the electric steering torque T that needs to be provided by the steering motor e :

[0050]

[0051] Among them, T h is the hand torque acting on the steering wheel, i is the transmission ratio from the steering wheel to the front wheels of the vehicle, i e It is the transmission ratio from the output of the reducer to the front wheels of the vehicle. Figure 1 The vehicle steering system 100 shown in FIG. e It can be calculated as i e =i c ·i g , where i c is the equivalent transmission ratio of the knuckle arm and the tie rod, and i g is the gear ratio of the steering gear.

[0052] In another example, the electric steering torque T can be obtained by solving the following equations simultaneously: e Calculate the target motor control current I tar :

[0053]

[0054]

[0055] Among them, J m is the moment of inertia of the steering motor, B mis the equivalent damping coefficient of the steering motor, θ e is the output shaft angle of the steering motor, i w is the transmission ratio of the reducer, U is the control voltage of the steering motor, K v is the equivalent back electromotive force coefficient of the steering motor, R is the equivalent resistance of the steering motor, and L is the equivalent inductance of the steering motor.

[0056] The manned driving control module 240-1 can be configured to calculate the target motor control current I based on the above algorithm from the vehicle front wheel angle θ tar However, other formulas, equations, mapping relationships, functional relationships, topological relationships, etc. may also be used to calculate the front wheel steering resistance torque from the vehicle front wheel steering angle and then calculate the target motor control current from the front wheel steering resistance torque. The correlation coefficients, parameters, function expressions, etc. used in the calculation may be pre-stored in the memory of the electronic control unit 24 and / or provided immediately by the information acquisition block 220.

[0057] In the case of intelligent driving, the target motor control current is aimed at making the vehicle turn accordingly along the planned path. Accordingly, the real-time vehicle front wheel steering angle obtained directly or indirectly is used to calculate the angle deviation from the target front wheel steering angle of the planned path, and then calculate the target motor control current corresponding to the electric steering torque to be provided by the steering motor.

[0058] In one example, based on the lateral path deviation e and the yaw rate deviation ω, the target front wheel turning angle θ is calculated using the following formula: tar :

[0059]

[0060] Among them, α and β are compensation coefficients, and k pe , k ie , k de , k pω , k iω , k dω is the pld control calculation parameter. Then, using the known current front wheel steering angle θ and the calculated target front wheel steering angle θ tar , the front wheel steering angle deviation between the current front wheel steering angle and the target front wheel steering angle can be calculated as Δθ=θ-θ tar .

[0061] In another example, the target motor control current I is calculated by the front wheel steering angle deviation Δθ using the following formula: tar :

[0062]

[0063] Among them, k p , ki , k p It is the pld control calculation parameter.

[0064] The intelligent driving control mode 240-2 can be configured to calculate the target motor control current I based on the above algorithm from the vehicle front wheel angle θ tar However, other formulas, equations, mapping relationships, functional relationships, topological relationships, etc. may also be used to calculate the deviation between the current front wheel angle and the target front wheel angle from the vehicle front wheel angle and then calculate the target motor control current from the front wheel angle deviation. The correlation coefficients, parameters, function expressions, etc. used in the calculation may be pre-stored in the memory of the electronic control unit 24 and / or provided immediately by the information acquisition block 220.

[0065] The driving mode determination module 240 - 12 is configured to determine the current driving mode of the vehicle so that the steering decision block can selectively use the manned driving control module 240 - 1 or the intelligent driving control module 240 - 2 to determine the target control current based on the current driving mode of the vehicle.

[0066] In one example, the current driving mode of the vehicle can be determined based on the pressure acting on the steering wheel. For example, the first vehicle-mounted sensor group may include a pressure sensor mounted to the steering wheel 12, and the pressure sensor is used to detect the pressure p acting on the steering wheel. The information acquisition module 220 obtains information about the pressure p from the pressure sensor and provides it to the driving mode judgment module 240-12. The driving mode judgment module 240-12 detects whether the pressure p meets the mode switching condition and determines the current driving mode of the vehicle based on whether the mode switching condition is met. For example, the intelligent driving mode can be defined as the steering wheel has not been used for a period of time. Accordingly, if it is detected that the pressure p is lower than a predetermined pressure threshold p0 for more than a predetermined holding time threshold t0 (i.e., p<p0&&t> t0), it can be determined that the current driving mode of the vehicle is the intelligent driving mode, otherwise it is considered that the vehicle is in the manned driving mode. Alternatively, other standards can also be used to define the intelligent driving mode, and the mode switching conditions for the driving mode determination module 240-12 are set accordingly.

[0067] After the steering decision block 240 selects one of the manned driving module 240-1 and the intelligent driving control module 240-2 to calculate the target motor control current value based on the determination of the driving mode determination module 240-12, the current generation block 260 is used to supply current to the steering motor according to the calculated target motor control current value, so that the steering motor can respond to the instantaneous electric steering torque demand during the vehicle driving process in a timely manner. That is, the current generation block 260 is configured to generate and output the target control current.

[0068] Figure 4A vehicle front wheel angle based steering control method 400 according to the principles of the present invention is illustrated in the form of a flow chart.

[0069] At step S410-1, multiple sensor signals are received from a first vehicle-mounted sensor group, and vehicle road information, vehicle operating status information, and vehicle-road correlation information are obtained based on the multiple sensor signals. The first vehicle-mounted sensor group includes a torque sensor configured to detect the hand torque applied by the driver to the steering wheel, and the vehicle operating status information includes the hand torque applied by the driver to the steering wheel.

[0070] Simultaneously with step S410 - 1 , at step S410 - 2 , a detection signal for a selected kinematic variable is received from a sensor mounted to the steering transmission mechanism, and a front wheel steering angle of the vehicle is acquired based on the detection signal.

[0071] Subsequently, at step S420, based on a plurality of sensor signals from the first vehicle-mounted sensor group, it is determined whether the vehicle operating state meets a predetermined intelligent driving control mode standard.

[0072] If the determination at step S420 is that the vehicle operating state meets the predetermined intelligent driving control mode standard (in Figure 4 If the value is “Y”, go to step S430.

[0073] At step S430, based on the information obtained in step S410-1, the target front wheel angle for vehicle steering is calculated. Subsequently, at step S450, the front wheel angle deviation is calculated based on the target front wheel angle calculated at step S430 and the front wheel angle obtained at step S410-2. Thereafter, at step S470, the target motor control current is calculated based on the front wheel angle deviation calculated at step S450. Finally, at step S490, according to the calculated target motor control current, a current is generated and output to the steering motor for steering control.

[0074] If the determination at step S420 is that the vehicle operating state does not satisfy the predetermined intelligent driving control mode standard (in Figure 4 If the value is “N”, go to step S440.

[0075] At step S440, the instantaneous steering resistance torque of the front wheels of the vehicle is calculated based on the front wheel angle obtained at step S410-2. Subsequently, at step S460, the electric steering torque to be provided by the steering motor is calculated based on the instantaneous steering resistance torque calculated at step S440 and the hand torque obtained at step S410-1. Thereafter, at step S480, the target motor control current is calculated based on the electric steering torque calculated at step S460. Finally, at step S490, according to the calculated target motor control current, a current is generated and output to the steering motor for steering control.

[0076] The method 400 may be programmed as instructions or computer programs that can be executed by a processor of the electronic control unit 24 and repeatedly executed during vehicle driving. The various features described in this application with reference to the electronic control unit are also applicable to the control method of this application and will not be described in detail here.

[0077] The present application also provides a machine-readable (computer-readable) storage medium storing executable instructions, which implement the control method described above when executed by a processor.

[0078] Thus, the preferred practice methods of practicing the vehicle steering control strategy based on the front wheel angle of the present disclosure known to the inventor have been described in detail from the two dimensions of process method and system architecture. To make the description concise, certain elements or features according to the principles of the present disclosure may be described in combination with the process method, and other elements or features according to the principles of the present disclosure may be described in combination with the system architecture. It is understood that the elements or features stated in combination with different aspects may be combined with each other to form other embodiments not specifically described in this application. Such embodiments are also included within the scope of the present invention.

Claims

1. An electronic control unit for an electric power steering system of a vehicle, comprising: an information acquisition block configured to receive a sensor signal related to an electric power steering of the vehicle and determine a real-time front wheel steering angle of the vehicle based on the sensor signal; a steering decision block configured to determine a current driving mode of the vehicle based on the sensor signal and calculate a target control current to be provided using the real-time front wheel steering angle according to the determined current driving mode; as well as A current generating block is configured to generate and output the target control current.

2. The electronic control unit for the vehicle electric power steering system according to claim 1, wherein: The information acquisition block includes a front wheel steering angle estimation module configured to determine a real-time front wheel steering angle of the vehicle based on detection of selected kinematic variables of a steering transmission mechanism directly connected to the front wheels of the vehicle.

3. The electronic control unit for the vehicle electric power steering system according to claim 2, wherein: The steering transmission mechanism includes a rack and pinion steering gear, and the selected kinematic variable is the displacement of the rack of the steering gear relative to the pinion.

4. The electronic control unit for a vehicle electric power steering system according to claim 2 or 3, wherein: The information acquisition block is further configured to obtain the real-time front wheel steering angle of the vehicle from the detected value of the selected kinematic variable using a pre-stored functional relationship.

5. The electronic control unit for a vehicle electric power steering system according to any one of claims 1 to 3, wherein: The steering decision block includes a manned driving control module, which is configured to determine an immediate steering resistance torque based on the real-time front wheel angle and calculate a target control current to be provided based on the immediate steering resistance torque and detection information about a hand torque in the sensor signal.

6. The electronic control unit for a vehicle electric power steering system according to any one of claims 1 to 3, wherein: The steering decision block includes an intelligent driving control module configured to calculate a target control current using a difference between the real-time front wheel steering angle and a target front wheel steering angle.

7. The electronic control unit for the vehicle electric power steering system according to claim 6, wherein: The target front wheel turning angle is calculated based on the lateral path deviation and the yaw rate deviation.

8. The electronic control unit for a vehicle electric power steering system according to any one of claims 1 to 3, wherein: The steering decision block includes a driving mode determination module configured to determine a current driving mode of the vehicle based on detection information about pressure on a manual steering interface in the sensor signal.

9. The electronic control unit for the vehicle electric power steering system according to claim 8, wherein: The driving mode determination module is configured to determine that the current driving mode of the vehicle is the intelligent driving mode based on the pressure on the manual steering interface being lower than a predetermined pressure threshold for more than a predetermined holding time threshold.

10. A control method for an electric power steering system of a vehicle, optionally, the method is executed by an electronic control unit according to any one of claims 1 to 9, the method comprising: receiving a sensor signal associated with an electric power steering of the vehicle, and determining a real-time front wheel steering angle of the vehicle based on the sensor signal; determining a current driving mode of the vehicle based on the sensor signal; Calculating a target control current to be provided using the real-time front wheel steering angle according to the determined current driving mode; as well as The target control current is generated and outputted.

11. A machine-readable storage medium storing executable instructions, wherein the instructions implement the control method according to claim 10 when executed by a processor.

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