A steering control method, device, steering system and vehicle

Abstract

The application belongs to the field of intelligent driving and relates to intelligent automobile steering technology in the field. Specifically, a steering control method and device, a steering system and a vehicle are provided. The method comprises: obtaining a reference information set, the reference information set comprising a steering wheel torque, a motor speed, a motor torque and a vehicle speed signal; when a first condition is met, obtaining a first torque according to the reference information set; obtaining a third torque according to the first torque and a second torque, and controlling steering according to the third torque; wherein the second torque is obtained by open-loop torque control of the steering system. Based on the technical solution provided in the application, the experience of the user when returning to the wheel can be improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of vehicles, in particular to a steering control method and device, a steering system and a vehicle. BACKGROUND

[0002] With the increasing demand of users for driving feel, the problem that the traditional electric power steering system (EPS) is difficult to ensure the smoothness of the steering feel when returning to the wheel is gradually valued, especially in the case of low vehicle speed, the problem of smoothness of the steering feel when returning to the wheel is more prominent. Figure 1 The numerical relationship between the steering wheel torque and the steering gear pinion angle with time is shown, and the abnormal jump of the steering wheel torque occurs in the first time interval (0.75s-0.80s) and the second time interval (0.90s-0.95s). The abnormal jump indicates that the steering feel is not smooth when returning to the wheel. It is verified by experiments that the driving experience of the steering feel is positively correlated with the front axle weight of the vehicle, for example, the steering feel is more uneven when returning to the wheel for large SUVs, and the uneven steering feel cannot be avoided whether a column type EPS or a rack type EPS is used. How to properly solve the problem of uneven steering feel when returning to the wheel has become a problem to be solved in the industry. SUMMARY

[0003] In view of the above problems of the prior art, the present application provides a steering control method, device, system and vehicle to solve the problem of uneven user steering feel when returning to the wheel.

[0004] To achieve the above-mentioned purpose, the first aspect of the present application provides a steering control method, comprising obtaining a reference information set, the reference information set comprising a steering wheel torque, a motor speed, a motor torque and a vehicle speed signal. When a first condition is met, a first torque is obtained according to the reference information set. A third torque is obtained according to the first torque and a second torque, and the steering is controlled according to the third torque; wherein the second torque is obtained by open-loop torque control of the steering system. The first condition is used to indicate the uneven steering feel when returning to the wheel, i.e. the convex jump of the hand on the steering wheel.

[0005] The technical solution provided by the present application, by digging out the internal mechanism of the uneven steering feel when returning to the wheel, and building a compensation torque for the uneven steering feel, i.e. the first torque, specifically: considering the steering wheel torque, the motor speed, the motor torque and the vehicle speed signal and other characteristics, when the uneven steering feel when returning to the wheel is monitored (the first condition is met), the first torque is calculated by using the above-mentioned multiple characteristics, and then the third torque is obtained according to the first torque and the second torque, and the third torque is used as the final torque for controlling the steering. The second torque can be well compensated, and the problem of uneven steering feel when returning to the wheel can be overcome, and the user experience can be improved.

[0006] As an implementation form of the first aspect, the first condition comprises: when the direction of the motor speed and the direction of the motor torque are different, and the steering wheel torque and the vehicle speed signal meet respective preset threshold conditions.

[0007] From the above, the first condition can accurately identify whether the hand feeling is uneven when the wheel is returned.

[0008] As an implementation form of the first aspect, the reference factor set further comprises: the steering gear pinion angle.

[0009] As an implementation form of the first aspect, the first condition comprises: when the steering wheel torque, the vehicle speed signal, and the steering gear pinion angle meet respective preset threshold conditions, and the direction of the motor speed and the direction of the motor torque are different.

[0010] From the above, the steering gear pinion angle is taken as one of the elements in the reference factor set, which can make the monitored wheel return hand feeling more accurate.

[0011] As an implementation form of the first aspect, obtaining the first torque according to the reference information set comprises: determining a second rack force according to the motor speed and the motor torque. Determining a fourth torque according to the second rack force. Determining the first torque according to the fourth torque.

[0012] As an implementation form of the first aspect, determining the second rack force according to the motor speed and the motor torque comprises: determining a first rack force according to the motor speed and the motor torque. Converting the first rack force to the motor rotor coordinate system to obtain the second rack force.

[0013] As an implementation form of the first aspect, the second rack force can be determined according to the motor speed and the motor torque by using the state space-based observer theory and pole placement.

[0014] From the above, in order to overcome the situation that the open-loop torque control will inevitably result in insufficient wheel return assistance in the application scenario of the flexible torsion bar, the second rack force is obtained by the above method, which is taken as the input of the fourth torque signal. By learning from the closed-loop control of the compensation torque signal, the disadvantages of the open-loop torque control are broken, and appropriate assistance can be provided to resist the self-aligning force generated by the suspension and the tire when the wheel is returned.

[0015] As an implementation form of the first aspect, determining the fourth torque according to the second rack force comprises: when the first condition is met, obtaining a first signal corresponding to the vehicle speed signal in a preset first table, a high-frequency signal of the motor speed, and a second signal corresponding to the second rack force in a preset second table to determine the fourth torque.

[0016] The first table is a one-dimensional lookup table module with an input of a vehicle speed signal and an output representing a moment of inertia; and the second table is a one-dimensional lookup table module with an input of a second rack force and an output representing a compensation torque.

[0017] According to an implementation form of the first aspect, the corresponding first signal in the first table is determined according to a driving mode.

[0018] According to an implementation form of the first aspect, the corresponding second signal in the second table is determined according to a driving mode.

[0019] As described above, in the open-loop control, the reduction of the steering wheel torque during the return of the wheels will cause a reduction of the assistance, and at the moment of the return of the wheels, the self-aligning force of the tires and the suspension does not change abruptly, which causes the assistance to be unable to resist the self-aligning force, resulting in a feeling of unevenness during the return of the wheels. In order to avoid this problem, the idea of the closed-loop control is borrowed, and when the feeling of unevenness during the return of the wheels is monitored, a preliminary compensation torque signal is determined based on the second rack force, the first signal and the high-frequency signal of the motor speed, which can ensure that even when the steering wheel torque is reduced, there is still sufficient assistance to resist the unintended movement of the tires, thereby avoiding the problem of unevenness of the steering wheel torque.

[0020] According to an implementation form of the first aspect, determining the first torque according to the fourth torque comprises: determining a first intervention factor based on the steering wheel torque and the vehicle speed signal; performing an exponential operation on the first intervention factor to obtain a second intervention factor; and determining the first torque according to the second intervention factor and the fourth torque.

[0021] As described above, by considering the steering wheel torque and the vehicle speed signal as an intervention, the human-machine interaction is introduced to adjust the compensation torque signal, which can make the output first torque more scientific and reasonable.

[0022] According to an implementation form of the first aspect, the third torque acts on any one or more of a column type electric power steering system, a gear type electric power steering system or a rack type electric power steering system.

[0023] A second aspect of the present application provides a steering control device, comprising: an acquisition module configured to acquire a reference information set, the reference information set comprising a steering wheel torque, a motor speed, a motor torque and a vehicle speed signal; a first determination module configured to obtain a first torque according to the reference information set when a first condition is met; and a second determination module configured to obtain a third torque according to the first torque and a second torque, and to control steering according to the third torque; wherein the second torque is obtained by open-loop torque control of a steering system.

[0024] According to an implementation form of the second aspect, the first condition comprises: when the direction of the motor speed and the direction of the motor torque are different, and the steering wheel torque and the vehicle speed signal meet respective preset threshold conditions.

[0025] As an implementation form of the second aspect, the reference information set further comprises: a steering pinion rotation angle.

[0026] As an implementation form of the second aspect, the first condition comprises: when the steering wheel torque, the vehicle speed signal, and the steering pinion rotation angle meet respective preset threshold conditions, and the direction of the motor speed and the direction of the motor torque are different, it is monitored that the steering wheel feels uneven.

[0027] As an implementation form of the second aspect, the first determination module comprises: a first determination unit configured to determine a second rack force according to the motor speed and the motor torque; a second determination unit configured to determine a fourth torque according to the second rack force; and a third determination unit configured to determine the first torque according to the fourth torque.

[0028] As an implementation form of the second aspect, the first determination unit comprises: a first determination sub-unit configured to determine a first rack force according to the motor speed and the motor torque; and a conversion sub-unit configured to convert the first rack force to a motor rotor coordinate system to obtain the second rack force.

[0029] As an implementation form of the second aspect, the second determination unit is specifically configured to: when the first condition is met, obtain a first signal corresponding to the vehicle speed signal in a preset first table, a high-frequency signal of the motor speed, and a second signal corresponding to the second rack force in a preset second table, to determine the fourth torque.

[0030] As an implementation form of the second aspect, the first signal corresponding to the first table is determined according to a driving mode.

[0031] As an implementation form of the second aspect, the second signal corresponding to the second table is determined according to a driving mode.

[0032] As an implementation form of the second aspect, the third determination unit comprises: a second determination sub-unit configured to determine a first intervention factor based on the steering wheel torque and the vehicle speed signal; an operation sub-unit configured to perform exponential operation on the first intervention factor to obtain a second intervention factor; and a third determination sub-unit configured to determine the first torque according to the second intervention factor and the fourth torque.

[0033] As an implementation form of the second aspect, the third torque acts on any one or more of a column type electric power steering system, a gear type electric power steering system, or a rack type electric power steering system.

[0034] The third aspect of the present application provides a computing device, comprising: at least one processor; and at least one memory connected with the processor and storing program instructions, the program instructions, when executed by the at least one processor, causing the at least one processor to perform the steering control method of any one of the first aspect.

[0035] The fourth aspect of the present application provides a steering system, comprising: a steering wheel, a steering shaft, a steering system and a motor; the steering system is controlled by the steering control method of any one of the first aspect to steer.

[0036] The fifth aspect of the present application provides a vehicle, comprising the steering system of the fourth aspect.

[0037] The sixth aspect of the present application provides a computer readable storage medium, having stored thereon program instructions, the program instructions, when executed by a computer, causing the computer to perform the steering control method of any one of the first aspect.

[0038] These and other aspects of the present application will become more fully understood from the following (a plurality of) embodiment descriptions. BRIEF DESCRIPTION OF DRAWINGS

[0039] The various features and the relationships between the various features of the present application will be further illustrated below with reference to the accompanying drawings. The drawings are all exemplary, some features are not shown in actual proportion, and some features in the drawings can omit the features that are conventional in the field to which the present application pertains and are not essential to the present application, or additional features that are not essential to the present application are shown, and the combination of the various features shown in the drawings is not intended to limit the present application. In addition, throughout the specification, the same reference signs refer to the same things. The specific drawings are as follows:

[0040] Figure 1 Schematic diagram of hand force unevenness when the steering wheel is operated back and forth in the prior art;

[0041] Figure 2 Logic block diagram of the steering control method provided by the embodiment of the present application;

[0042] Figure 3 Architecture diagram of the steering control method provided by the embodiment of the present application;

[0043] Figure 4 Flowchart of the steering control method provided by the embodiment of the present application;

[0044] Figure 5 Logic block diagram of the monitoring of the hand feeling of the steering wheel provided by the embodiment of the present application;

[0045] Figure 6 Flowchart of the determination of the first torque provided by the embodiment of the present application;

[0046] Figure 7 A structural schematic diagram of a steering system provided for an embodiment of the present application is shown in FIG. 1.

[0047] Figure 8 A logic block diagram for determining the second rack force provided for an embodiment of the present application is shown in FIG. 2.

[0048] Figure 9 A logic block diagram for determining the fourth torque provided for an embodiment of the present application is shown in FIG. 3.

[0049] Figure 10 A logic block diagram for determining the first torque provided for an embodiment of the present application is shown in FIG. 4.

[0050] Figure 11 A structural schematic diagram of a steering control device is shown in FIG. 5.

[0051] Figure 12 A structural schematic diagram of a computing device provided for an embodiment of the present application is shown in FIG. 6. DETAILED DESCRIPTION

[0052] The words "first", "second", "third", etc. or similar words as used in the description and claims, such as module A, module B, module C, etc., are used only to distinguish similar objects, and do not represent a specific order or sequence of the objects. It is understood that the specific order or sequence can be changed, if allowed, so that the embodiments of the present application described herein can be implemented in an order other than that illustrated or described herein.

[0053] In the following description, the reference signs denoting steps, such as S110, S120, etc., do not necessarily mean that the steps are executed in the order as shown. The order of the steps can be changed, if allowed, or the steps can be executed simultaneously.

[0054] The term "comprising" as used in the specification and claims should not be interpreted as limiting to the listed elements; it does not exclude other elements or steps. It thus should be interpreted as specifying the presence of the stated features, integers, steps or components as referred to, but does not preclude the presence or addition of one or more other features, integers, steps or components, or groups thereof. Thus, the expression "a device comprising means A and B" should not be construed as being limited to a device only comprising the means A and B.

[0055] Reference in this specification to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the application. The appearances of the phrase "in one embodiment" or "in an embodiment" in various places in the specification are not necessarily all referring to the same embodiment, but can refer to different embodiments. Furthermore, the particular features, structures, or characteristics can be combined in any suitable manner in one or more embodiments.

[0056] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description of the application herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0057] In the following, first the related art is introduced in detail, and then the technical solutions of the present application are introduced in detail.

[0058] As shown in Table 1, a compensation scheme for the unevenness of the hand feeling when returning to the wheel in the related art is provided.

[0059] Table 1 Technical solutions for improving the unevenness of the hand feeling when returning to the wheel

[0060]

[0061] According to Table 1, the first way can improve the unevenness of the hand feeling when returning to the wheel by increasing the friction. Specifically, the algorithm inside the EPS is used to increase the compensation friction. However, the degree of improvement of the unevenness of the hand feeling by increasing the friction is not significant, and at the same time, too much friction will cause the hand feeling to be too light, causing the driver to have the illusion of inaccurate steering, causing too much interference to normal driving, and seriously reducing the user's driving experience.

[0062] According to Table 1, the second way can improve the unevenness of the hand feeling when returning to the wheel by high-frequency assistance. Specifically, the cut-off frequency is reduced and the high-frequency assistance coefficient is increased to increase the EPS assistance. However, this way will cause a small hand force to cause a large amplitude rotation of the steering wheel at the center position of the steering wheel, so that the user obtains a "light" driving experience. In addition, the EPS system is a dynamic closed-loop system, and the subsequent effects of a certain operation will act on the ECU of the system. The large amplitude assistance gain caused by the small hand force may cause the subsequent commands of the ECU to be uncontrollable, thereby reducing the stability of the system.

[0063] According to Table 1, the third mode can improve the problem of uneven hand feeling when returning to the wheel by compensating for system stability. Specifically, it is realized by reducing the attenuation of the low frequency band of the system. For example: the original attenuation of the low frequency band of the system is x%, and now the attenuation of the low frequency band of the system is y%, where y < x. Equivalent to the percentage of the low frequency band of the system that is not attenuated increases, which will increase the assistance of the EPS, but the load of the system does not change. As in the second mode described above, it will also bring a fluctuating driving experience, which will lead to a decrease in system stability.

[0064] According to Table 1, the fourth mode can improve the problem of uneven hand feeling when returning to the wheel by increasing the basic assistance. Specifically, it is to increase the assistance coefficient of the basic assistance in the small torque region. This way directly increases the assistance coefficient in the small torque region, which can also increase the assistance of the EPS, but the load of the system in the small torque region does not change, which will cause the assistance of the EPS in the center position region of the steering wheel to be higher than the actual required assistance. If the assistance coefficient changes slightly, the effect of improving the uneven hand feeling will not be significant; if the assistance coefficient changes greatly, the increased assistance of the EPS will lead to a decrease in system stability.

[0065] Before detailing the method for controlling steering provided by the embodiments of the present application, first introduce the relationship between the technical terms in the embodiments of the present application: in the following embodiments of the present application, the compensation torque signal can be referred to as the first torque. The original electric power steering torque signal can be referred to as the second torque. The integrated electric power steering torque signal can be referred to as the third torque. The preliminary compensation torque signal can be referred to as the fourth torque.

[0066] Based on the research on related technologies and the defects of related technologies, one embodiment of the present application provides a method for controlling steering, as shown in Figure 2 As shown in the logic diagram of the method for controlling steering, specifically, by introducing the hand wheel torque (HWT), pinion angle (Pin_Ag), motor velocity (Mot_Vel), motor torque (MT) and vehicle speed signal (VS) to obtain the compensation torque signal (SmhCmp_MotTrq) (i.e. the first torque), superimpose the first torque and the original electric power steering torque signal (i.e. the second torque), obtain the torque requested by the motor, i.e. the third torque (also referred to as the integrated electric power steering torque signal), and control steering using the third torque to achieve the purpose of compensating for the uneven hand feeling when returning to the wheel.

[0067] The embodiments of this application will now be described in detail with reference to the accompanying drawings. First, the application scenario of a steering control method provided by the embodiments of this application will be introduced.

[0068] The steering control method provided in this application is applicable to electric power steering (EPS) systems with open-loop torque control. A typical characteristic of this application is that the EPS's assist torque and steering wheel torque are obtained through open-loop control. When an uneven return wheel feel is detected, the steering control method provided in this application is used to compensate for the assist torque to ensure smoothness of the feel. Specifically, when an abnormal sudden jump in steering wheel torque is detected during the return wheel process (e.g., ... Figure 1 The time intervals of 0.75s-0.80s and 0.90s-0.95s shown can be considered as detecting an uneven return feel. Specifically, such as... Figure 3 The diagram shown is an architecture diagram of the steering control method provided in this application embodiment. It monitors whether there is any unevenness in the steering feel when returning the wheel to center based on steering wheel torque, motor speed, motor torque, steering gear pinion angle, and vehicle speed signals; it determines the second rack force based on motor speed and motor torque; it determines a preliminary compensation torque signal based on the second rack force, the flag indicating unevenness in the steering feel when returning the wheel to center, motor speed, and vehicle speed signals; it determines a final compensation torque signal based on the preliminary compensation torque signal, steering wheel torque, and vehicle speed signals; and then it uses the compensation torque signal to compensate for the assist torque, thus achieving compensation for the smoothness of the steering feel.

[0069] For example, the steering control method can be stored in local memory and communicate with the EPS via a bus; the steering control method can also be stored in remote memory and the method can be sent back to local memory. This application does not impose any special restrictions on the storage location of the steering control method.

[0070] The following describes in detail, with reference to the figures, a steering control method provided in the embodiments of this application.

[0071] like Figure 4 The diagram shown is a flowchart of a steering control method provided in an embodiment of this application. The process mainly includes steps S110-S130, which are described in detail below:

[0072] S 110: Obtain a set of reference information, which includes steering wheel torque, motor speed, motor torque and vehicle speed signals.

[0073] In this embodiment, as another optional implementation, the set of reference factors may further include the steering pinion angle (Pin_Ag).

[0074] wherein the motor torque is the product of the motor current in q-axis (Mot Q Curr) and the electromagnetic constant, since the electromagnetic constant is a constant value, the variation trend of the motor torque can be represented by the variation trend of the motor current in q-axis. In addition, the steering wheel torque is the product of the hand force (HW Trq) applied on the steering wheel and the force arm of the steering wheel, and for the same reason, since the force arm of the steering wheel is a constant value, the variation trend of the steering wheel torque can be represented by the hand force applied on the steering wheel.

[0075] As an optional implementation, the steering wheel torque can be obtained by a torque sensor. The motor speed is monitored by a relevant monitoring device in the motor to obtain the electrical angle of the motor, and then the motor speed is obtained by differential calculation. Monitoring the torque of the motor is equivalent to monitoring the q-axis current of the motor, which is usually monitored by a relevant monitoring device in the motor to monitor the current flowing through the three-phase winding of the armature and calculated according to the electrical angle of the motor. The vehicle speed signal can be calculated by monitoring the number of revolutions of the tire per unit time and the radius of the tire.

[0076] S 120: When the first condition is met, a first torque is obtained according to the reference information set. The first condition is used to indicate that the phenomenon of uneven steering wheel feeling is monitored.

[0077] In this step, first of all, it needs to be explained that in the process of returning the steering wheel, the driver controls the steering wheel to return to the correct position according to the speed of the driving intention; the lower end of the steering wheel is connected to the flexible torque of the torque sensor; and the other end of the flexible torque is connected to the pinion. The smooth steering wheel feeling refers to the process that the hand force applied by the user on the steering wheel gradually decreases as the steering wheel gradually returns to the correct position. The radius of the steering wheel is fixed, so it is equivalent to the process that the steering wheel torque gradually decreases as the steering wheel gradually returns to the correct position. The gradual decrease of the steering wheel torque will cause the assist torque provided by the EPS to gradually decrease, which will cause the return torque of the tire and the suspension to be greater than the sum of the steering wheel torque and the assist torque provided by the EPS at a certain moment, which will cause the pinion to move unexpectedly, thereby causing the two ends of the torque sensor (the steering angle and the rotation angle of the pinion) to change out of sync, resulting in a sudden jump of the steering wheel torque signal, forming an uneven feeling. Therefore, whether the steering wheel feeling is uneven can be determined by monitoring whether the steering wheel torque jumps. During the process of experiencing uneven steering wheel feeling, the user's feeling will first have an unexpected sharp decrease, then will have a rebound increase, and then will return to normal.

[0078] It should be understood that step S 120 is divided into two parts, the first part is the monitoring of the steering wheel feeling (i.e. judging whether the first condition is met); the second part is to determine the first torque according to the reference factor set.

[0079] Below, we will first introduce in detail the part about monitoring the feel of the return wheel.

[0080] Specifically, as an optional implementation, when the direction of the motor speed and the direction of the motor torque are not the same, and the steering wheel torque and the vehicle speed signal meet their respective preset threshold conditions, it is considered that the steering wheel feel is not smooth (i.e., the first condition is met).

[0081] In this embodiment, when the set of reference factors may also include the steering gear pinion angle, as another optional implementation, when the direction of the motor speed and the direction of the motor torque are not the same, and the steering wheel torque, the vehicle speed signal, and the steering gear pinion angle meet their respective preset threshold conditions, it is considered that the steering wheel return feel is not smooth.

[0082] like Figure 5 The diagram shows the logic block for monitoring the return wheel's feel. As an optional implementation, determining whether the direction of the motor speed and the direction of the motor torque are the same involves: first, performing a low-pass filter on the motor speed and torque; then, judging the signs of the filtered motor speed and torque. If the signs are different, the direction of the motor speed and the direction of the motor torque force are considered different, and this is recorded as -1; if the signs are the same, the direction of the motor speed and the direction of the motor torque force are considered the same, and this is recorded as 1. For ease of understanding, this step can be understood as calculating the motor's operating quadrant. Then, the result of the motor operating quadrant judgment is compared with -1. If they are the same (i.e., both are -1), then 1 is output; if they are different (i.e., one is 1 and the other is -1), then -1 is output.

[0083] As an optional implementation method, determining whether the steering wheel torque meets the preset threshold conditions includes: first, performing low-pass filtering on the steering wheel torque; then, performing differential calculation on the low-pass filtered signal; then, taking the absolute value of the differentially calculated signal; comparing the absolute value with the preset minimum steering wheel torque change rate; and outputting 1 when the absolute value is not less than the preset minimum steering wheel torque change rate, otherwise outputting -1.

[0084] As an optional implementation, determining whether the vehicle speed signal meets the respective preset threshold conditions includes: comparing the vehicle speed signal with the preset maximum vehicle speed signal; if the vehicle speed signal is not greater than the preset maximum vehicle speed signal, then output 1; otherwise, output -1.

[0085] As an optional implementation, judging whether the steering wheel torque meets the respective preset threshold condition is the same as judging whether the steering machine pinion gear rotation angle meets the respective preset threshold condition, including: first performing low-pass filtering on the steering machine pinion gear rotation angle, then performing differential calculation on the signal after low-pass filtering, and then taking the absolute value of the signal after differential calculation, and comparing the absolute value with the preset maximum angular change rate, when the absolute value is not greater than the preset maximum angular change rate, output 1, otherwise output -1. It should be understood that when the steering machine pinion gear rotation angle is not included in the reference factor set, this step of judgment is not required.

[0086] When all the above parts output 1, it is considered that the back wheel hand feeling unevenness phenomenon is monitored (i.e. the first condition is met). As long as there is a part outputting -1, it is considered that the back wheel hand feeling unevenness phenomenon is not monitored (i.e. the first condition is not met).

[0087] Next, the process of determining the first torque according to the reference factor set is described in detail.

[0088] As shown in Figure 6 , it is a flow chart of determining the first torque according to the reference factor set. The process mainly includes steps S610-S630, which are introduced one by one as follows:

[0089] S610: determining the second rack force according to the motor speed and the motor torque.

[0090] Among them, the rack force refers to the force between the steering machine pinion gear and the rack. As shown in Figure 7 , it is a structural schematic diagram of the steering system. Among them, 710 is the steering machine pinion gear, 720 is the rack, and the rack force is the force generated by the relative motion between the steering machine pinion gear 710 and the rack 720. It should be understood that for a column type electric power steering system, the rack force is the force applied to the column; for a gear type electric power steering system, the rack force is the force applied to the gear; for a rack type electric power steering system, the rack force is the force applied to the rack.

[0091] As an optional implementation, first, the first rack force needs to be determined according to the motor speed and the motor torque, which can be obtained by a state space-based observer. Then, the first rack force is converted to the motor rotor coordinate system to obtain the second rack force. Specifically, as shown in Figure 8As shown, a logic block diagram for determining the second rack force is provided, i.e. taking the motor torque and the motor speed as inputs of the state space based observer, the first rack force can be obtained through the state equation and the observation equation combined with the theory of pole placement, and then the first rack force is coordinate transformed to obtain the second rack force in the motor rotor coordinate system. The state equation is as follows (1) and (2), and the observation equation is as follows (3):

[0092]

[0093] Wherein, F mot = ke*I q *n*η, F mot is the thrust of the motor torque acting on the rack end, ke is the electromagnetic constant of the assist motor, I q (unit A) is the q-axis current of the motor, which can be obtained by converting the three-phase current of the motor winding and the electrical angle, and the three-phase current of the motor winding and the electrical angle can be directly tested by the detection device in the motor, n is the transmission ratio of the motor rotating direction converted to the linear direction of the rack, η is the transmission efficiency of the motor rotating direction converted to the linear direction of the rack, M is the mass of the rack (kg), v is the linear moving speed of the rack (m / s), is the derivative of v, C is the damping coefficient when the rack moves, F R is the first rack force (N), is the derivative of F R .

[0094] Through the above (1)-(3) and combined with the theory of pole placement, the first rack force can be obtained.

[0095] S620: determining the fourth torque according to the second rack force.

[0096] As Figure 9As an optional implementation manner, the first signal corresponding to the first table is obtained first, wherein the first table is a one-dimensional look-up table module with the vehicle speed signal as the input and the output representing the moment of inertia. The one-dimensional look-up table module mentioned herein and in the second table is based on a preset specific output at a specific input point, such as x1, x2…xn corresponding to y1, y2…yn, and the output signal y is obtained according to the position of the input signal x in the specific input point sequence xl, x2…xn by linear interpolation. Then, the motor speed is low-pass filtered to obtain a high-frequency signal of the motor speed, and the high-frequency signal is negated and added to the motor speed before low-pass filtering to obtain a differential signal of the processed motor speed. The product of the motor speed differential signal and the first signal is negated to obtain a first intermediate value. Then, the second rack force corresponding signal in the preset second table is obtained, wherein the second table is a one-dimensional look-up table module with the second rack force as the input and the output representing the compensated torque value. The product of the sum of the second signal and the first intermediate value and the hand feeling monitoring result when the steering wheel is returned is multiplied, and then low-pass filtered to obtain a preliminary compensation torque signal. The hand feeling monitoring result when the steering wheel is returned is uneven, and the hand feeling monitoring result when the steering wheel is returned is 1. The hand feeling monitoring result when the steering wheel is returned is smooth, and the hand feeling monitoring result when the steering wheel is returned is -1.

[0097] As an optional implementation manner, the first signal corresponding to the first table can be determined according to the driving mode. Similarly, the second signal corresponding to the second table can be determined according to the driving mode. The driving mode includes but is not limited to sports mode, normal mode, comfort mode, etc. The fourth torque obtained in the sports mode is larger, the fourth torque obtained in the normal mode is medium, and the fourth torque obtained in the comfort mode is slightly smaller.

[0098] S630: determining the first torque according to the fourth torque. The process includes three steps. The first step is to determine a first intervention factor based on the steering wheel torque and the vehicle speed signal. The second step is to perform exponential operation on the first intervention factor to obtain a second intervention factor. The third step is to determine the first torque according to the second intervention factor and the fourth torque. The specific implementation manner of each step is described in detail below.

[0099] As shown in FIG. 6, Figure 10 As shown in FIG. 6, a logic block diagram for determining the first torque is shown. As an optional implementation manner, the steering wheel torque is low-pass filtered through a low-pass filter first, and then the low-pass signal is taken as an absolute value to obtain a processed steering wheel torque signal value. Then, the first signal corresponding to the first table is obtained, and then the first signal and the processed steering wheel torque signal value are multiplied to obtain a first intervention factor.

[0100] Exponentiating the first intervention factor to obtain a second intervention factor.

[0101] Multiplying the second intervention factor with the fourth torque signal, if the result is within a preset range, the result is the first torque.

[0102] S130: determining a third torque according to the first torque and the second torque, and controlling the steering by using the third torque.

[0103] In this step, the first torque and the second torque are summed to obtain the third torque. The steering of the steering system is controlled by using the third torque, which can overcome the problem of uneven feeling during the return wheel process.

[0104] The embodiments of the present application construct the monitoring condition of the uneven feeling of the return wheel by studying the internal mechanism of the uneven feeling of the return wheel of the steering wheel. In order to overcome the insufficient return wheel assistance situation that will inevitably occur in the application scene of the open-loop torque control algorithm in the flexible torsion bar, the embodiments of the present application break the disadvantages of open-loop control by constructing the rack force, so as to provide more suitable assistance to resist the self-aligning force generated by the suspension and the tire during the return wheel, and avoid the uneven feeling during the return wheel. In addition, the embodiments of the present application also introduce the harmonious factor (the first intervention factor and the second intervention factor) of human-computer interaction to debug the first torque, so that the unevenness of the system is compensated.

[0105] Another embodiment of the present application provides a steering control device, which can be realized by a software system, a hardware device, or a combination of the software system and the hardware device.

[0106] It should be understood that, Figure 11 Only a structural schematic diagram of the steering control device is exemplarily shown, and the present application does not limit the division of the functional modules in the steering control device. As Figure 11 shown, the steering control device can be logically divided into multiple modules, each module can have different functions, and the function of each module is realized by the processor in the computing device reading and executing the instructions in the memory. For example, the steering control device can include an acquisition module 810, a first determination module 820 and a second determination module 830. In an optional implementation, the steering control device is configured to perform Figure 4The steps S110-S130 are described. Specifically, the steps S110-S130 can include: an acquisition module 810, configured to acquire a reference information set, the reference information set including a steering wheel torque, a motor speed, a motor torque, and a vehicle speed signal; a first determination module 820, configured to obtain a first torque according to the reference information set when a first condition is met; a second determination module 830, configured to obtain a third torque according to the first torque and a second torque, and control steering according to the third torque, wherein the second torque is obtained by open-loop torque control of a steering system.

[0107] Optionally, the first condition in the first determination module 820 includes: when the direction of the motor speed and the direction of the motor torque are different, and the steering wheel torque and the vehicle speed signal meet respective preset threshold conditions.

[0108] In some embodiments, the first determination module 820 includes: a first determination unit 821, a second determination unit 822, and a third determination unit 823. Specifically, the first determination unit 821 is configured to determine a second rack force according to the motor speed and the motor torque. The second determination unit 822 is configured to determine a fourth torque according to the second rack force. The third determination unit 823 is configured to determine the first torque according to the fourth torque.

[0109] As an optional implementation, the first determination unit 8201 includes: a first determination sub-unit, configured to determine a first rack force according to the motor speed and the motor torque; and a conversion sub-unit, configured to convert the first rack force to a motor rotor coordinate system to obtain the second rack force.

[0110] As an optional implementation, the second determination unit 822 is specifically configured to: when the first condition is met, obtain a first signal corresponding to the vehicle speed signal in a preset first table, a high-frequency signal of the motor speed, and a second signal corresponding to the second rack force in a preset second table, to determine the fourth torque. The first signal corresponding to the first table is determined according to a driving mode. The second signal corresponding to the second table is determined according to the driving mode.

[0111] As an optional implementation, the third determination unit 823 includes: a second determination sub-unit, configured to determine a first intervention factor based on the steering wheel torque and the vehicle speed signal; an operation sub-unit, configured to perform exponential operation on the first intervention factor to obtain a second intervention factor; and a third determination sub-unit, configured to determine the first torque according to the second intervention factor and the fourth torque.

[0112] In this embodiment, the reference information set can further include a steering machine pinion angle.

[0113] When the reference factor set further comprises a steering pinion angle, the first determining module 820 is specifically configured to monitor that the steering wheel feels uneven when the steering wheel torque, the vehicle speed signal, and the steering pinion angle meet respective preset threshold conditions, and the direction of the motor speed and the direction of the motor torque are different.

[0114] As an optional implementation, the third torque acts on any one or more of a column-type electric power steering system, a gear-type electric power steering system, or a rack-type electric power steering system.

[0115] The specific implementation of each functional module in this embodiment can be referred to the description in the method embodiments, and the embodiment will not be described again.

[0116] Figure 12 is a structural schematic diagram of a computing device 900 provided by an embodiment of the present application. The computing device 900 includes a processor 910, a memory 920, and a communication interface 930.

[0117] It should be understood that the communication interface 930 in the computing device 900 shown in the embodiment can be used for communication between the computing device 900 and other devices. Figure 12 The communication interface 930 in the computing device 900 shown in the embodiment can be used for communication between the computing device 900 and other devices.

[0118] The processor 910 can be connected with the memory 920. The memory 920 can be used for storing program codes and data. Therefore, the memory 920 can be a storage unit inside the processor 910, can be an external storage unit independent of the processor 910, or can be a component including the storage unit inside the processor 910 and the external storage unit independent of the processor 910.

[0119] Optionally, the computing device 900 can further include a bus. The memory 920 and the communication interface 930 can be connected with the processor 910 through the bus. The bus can be a peripheral component interconnect (PCI) bus or an extended industry standard architecture (EISA) bus, etc. The bus can be divided into an address bus, a data bus, a control bus, etc.

[0120] It should be appreciated that the processor 910 can be a central processing unit (CPU) in the embodiments of the present application. The processor can also be other general-purpose processors, digital signal processors (DSP), application specific integrated circuits (ASIC), field programmable gate arrays (FPGA) or other programmable logic devices, discrete gates or transistor logic components, discrete hardware components, etc. The general-purpose processor can be a microprocessor or the processor can also be any conventional processor. Alternatively, the processor 910 can be one or more integrated circuits for performing related programs to implement the technical solutions provided by the embodiments of the present application.

[0121] The memory 920 can include read-only memory and random access memory, and provide instructions and data to the processor 910. Part of the processor 910 can also include a non-volatile random access memory. For example, the processor 910 can also store device type information.

[0122] When the computing device 900 is running, the processor 910 executes computer execution instructions in the memory 920 to perform the operation steps of the above method.

[0123] It should be appreciated that the computing device 900 according to the embodiments of the present application can correspond to the execution of the corresponding subject in the method according to the embodiments of the present application, and the above and other operations and / or functions of each module in the computing device 900 are respectively for implementing the corresponding process of each method of the embodiments, and for brevity, will not be repeated here.

[0124] Those of ordinary skill in the art can realize that the units and algorithm steps of each example described in combination with the embodiments disclosed herein can be realized in electronic hardware or a combination of computer software and electronic hardware. Whether the functions are performed in hardware or software depends on the specific application and design constraints of the technical solutions. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present application.

[0125] Those skilled in the art can clearly understand that, for the convenience and brevity of the description, the specific working processes of the above-described system, device and unit can refer to the corresponding processes in the foregoing method embodiments, which will not be repeated here.

[0126] In several embodiments provided in the present application, it should be understood that the disclosed system, device and method can be implemented in other manners. For example, the described device embodiments are merely schematic. For example, the division of the units is only a logical function division. There can be another division manner for the actual implementation, for example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the displayed or discussed mutual couplings or direct couplings or communication connections can be indirect couplings or communication connections through some interfaces, devices or units, and can be in electrical, mechanical or other forms.

[0127] The units described as separate components can or can not be physically separate, and the components shown as units can or can not be physical units, i.e., can be located in one place, or can be distributed on multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the embodiment.

[0128] In addition, each functional unit in the various embodiments of the present application can be integrated into a processing unit, or each unit can exist physically, or two or more units can be integrated into one unit.

[0129] If the functions are realized in the form of software function units and sold or used as independent products, they can be stored in a computer readable storage medium. Based on this understanding, the technical solutions of the present application or the essential part or part of the technical solutions that make contributions to the prior art can be embodied in the form of a software product. The computer software product is stored in a storage medium, and includes several instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present application. The aforementioned storage medium includes: a U disk, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk, and various media that can store program codes.

[0130] The embodiments of the present application also provide a computer readable storage medium, which stores a computer program. The program is executed by a processor to execute a steering control method. The method includes at least one of the schemes described in the various embodiments.

[0131] The computer storage medium of the embodiments of the present application can adopt any combination of one or more computer-readable media. The computer-readable medium can be a computer-readable signal medium or a computer-readable storage medium. The computer-readable storage medium may, for example, but is not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, device or apparatus, or any combination thereof. More specific examples (non-exhaustive list) of the computer-readable storage medium include an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above. In this document, the computer-readable storage medium can be any tangible medium that contains or stores a program that can be used by or in connection with an instruction execution system, apparatus or device.

[0132] The computer-readable signal medium can include a data signal propagated in baseband or propagated as a carrier wave, in which computer-readable program code is embodied. Such propagated data signals can take a wide variety of forms, including but not limited to electro-magnetic signals, optical signals, or any suitable combination thereof. Computer-readable signal media can also be any computer-readable medium that is not a storage medium, that is, that is not a tangible medium, and that can communicate, propagate or transport programming for use by or in connection with an instruction execution system, apparatus or device.

[0133] The program code embodied on the computer-readable media can be transmitted using any appropriate medium, including but not limited to wireless, wired, optical fiber cable, RF, etc., or any suitable combination of the above.

[0134] Computer program code for carrying out operations of the present application can be written in any combination of one or more programming languages, including an object oriented programming language such as Java, Smalltalk, C++ or the like and conventional procedural programming languages, such as the "C" programming language or similar programming languages. The program code can execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on the remote computer or server. In the latter scenario, the remote computer can be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or the connection can be made to an external computer (for example, through the Internet using an Internet Service Provider). In some embodiments, electronic circuitry including, for example, programmable logic circuitry, application specific circuitry, or field programmable gate array (FPGA) circuitry can execute the computer program code.

[0135] Note that the above merely describes preferred embodiments of the present application and the applied technical principles. Those skilled in the art will understand that the present application is not limited to the specific embodiments described herein, and that various obvious changes, modifications and substitutions can be made to the present application without departing from the scope of the present application. Therefore, although the present application has been described in detail through the above embodiments, the present application is not limited to the above embodiments, and can include more other equivalent embodiments without departing from the concept of the present application, and all fall within the scope of the present application.

Claims

1. A steering control method characterized by, The method comprises: obtaining a reference information set comprising a steering wheel torque, a motor speed, a motor torque and a vehicle speed signal; when a first condition is met, determining a second rack force according to the motor speed and the motor torque; determining a fourth torque according to the second rack force; determining a first torque according to the fourth torque; obtaining a third torque according to the first torque and a second torque, and controlling steering according to the third torque; wherein the first condition comprises that the direction of the motor speed and the direction of the motor torque are different, and the steering wheel torque and the vehicle speed signal meet respective preset threshold conditions, and the second torque is obtained by open-loop torque control of a steering system.

2. The method of claim 1, wherein, The reference information set further comprises a steering gear pinion rotation angle.

3. The method of claim 2, wherein, The first condition comprises: when the steering wheel torque, the vehicle speed signal and the steering gear pinion rotation angle meet respective preset threshold conditions, and the direction of the motor speed and the direction of the motor torque are different.

4. The method of claim 1, wherein, The determination of the second rack force according to the motor speed and the motor torque comprises: determining a first rack force according to the motor speed and the motor torque; converting the first rack force into a motor rotor coordinate system to obtain the second rack force.

5. The method according to any one of claims 1 to 4, characterized in that, The determination of the fourth torque according to the second rack force comprises: when the first condition is met, obtaining a first signal corresponding to the vehicle speed signal in a preset first table, a high-frequency signal of the motor speed, and a second signal corresponding to the second rack force in a preset second table to determine the fourth torque.

6. The method of claim 5, wherein, The first signal corresponding in the first table is determined according to a driving mode.

7. The method of claim 5, wherein, The second signal corresponding in the second table is determined according to a driving mode.

8. The method according to any one of claims 1 to 7, characterized in that, The determination of the first torque according to the fourth torque comprises: determining a first intervention factor based on the steering wheel torque and the vehicle speed signal; performing exponential operation on the first intervention factor to obtain a second intervention factor; determining the first torque according to the second intervention factor and the fourth torque.

9. The method of claim 1, wherein, Further comprising: The third torque acts on any one or more of a column type electric power steering system, a gear type electric power steering system or a rack type electric power steering system.

10. A steering control device characterized by comprising: The method comprises: an obtaining module for obtaining a reference information set comprising a steering wheel torque, a motor speed, a motor torque and a vehicle speed signal; a first determining module comprising a first determining unit, a second determining unit and a third determining unit, when a first condition is met, the first determining unit is configured to determine a second rack force according to the motor speed and the motor torque, the second determining unit is configured to determine a fourth torque according to the second rack force, and the third determining unit is configured to determine a first torque according to the fourth torque; a second determining module for obtaining a third torque according to the first torque and a second torque, and controlling steering according to the third torque; wherein the first condition comprises that the direction of the motor speed and the direction of the motor torque are different, and the steering wheel torque and the vehicle speed signal meet respective preset threshold conditions, and the second torque is obtained by open-loop torque control of a steering system.

11. The apparatus of claim 10, wherein, The reference information set further comprises a steering wheel pinion rotation angle.

12. The apparatus of claim 11, wherein, The first condition comprises: When the steering wheel torque, the vehicle speed signal, and the steering wheel pinion rotation angle meet respective preset threshold conditions, and the direction of the motor speed and the direction of the motor torque are not the same.

13. The apparatus of claim 10, wherein, The first determination unit comprises: A first determination sub-unit configured to determine a first rack force according to the motor speed and the motor torque; A conversion sub-unit configured to convert the first rack force to a motor rotor coordinate system to obtain the second rack force.

14. The apparatus of any one of claims 10-13, wherein, The second determination unit is specifically configured to: When the first condition is met, obtain a first signal corresponding to the vehicle speed signal in a preset first table, a high-frequency signal of the motor speed, and a second signal corresponding to the second rack force in a preset second table to determine the fourth torque.

15. The apparatus of claim 14, wherein, The first signal corresponding to the first table is determined according to a driving mode.

16. The apparatus of claim 14, wherein, The second signal corresponding to the second table is determined according to a driving mode.

17. The apparatus of any of claims 10-16, wherein, The third determination unit comprises: A second determination sub-unit configured to determine a first intervention factor based on the steering wheel torque and the vehicle speed signal; An operation sub-unit configured to perform exponential operation on the first intervention factor to obtain a second intervention factor; A third determination sub-unit configured to determine the first torque according to the second intervention factor and the fourth torque.

18. The apparatus of claim 10, wherein, Further comprising: The third torque acts on any one or more of a column-type electric power steering system, a gear-type electric power steering system, or a rack-type electric power steering system.

19. A computing device, comprising: Comprise: At least one processor; And At least one memory connected with the processor and storing program instructions, the program instructions, when executed by the at least one processor, cause the at least one processor to execute a steering control method according to any one of claims 1-9.

20. A steering system characterized by, Comprise: A steering wheel, a steering shaft, a steering system, and a motor; the steering system is controlled by a steering control method according to any one of claims 1-9 to steer.

21. A vehicle characterized by A steering system according to claim 20.

22. A computer readable storage medium having stored thereon program instructions, wherein, The program instructions, when executed by a computer, cause the computer to execute a steering control method according to any one of claims 1-9. The program instructions, when executed by a computer, cause the computer to execute a steering control method according to any one of claims 1-9.

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