A steering assist control method and device for large new energy vehicles

Abstract

The application provides a steering assist control method and device for large new energy vehicles. In the application, compensation assist and bend compensation assist can automatically increase assist to offset the increase in righting moment caused by the surge in tire vertical load and lateral force when the vehicle is fully loaded or high-speed bends, preventing the driver from making mistakes or delaying reactions due to the sudden weight of the steering wheel in critical situations (such as emergency obstacle avoidance or high-speed bending). Based on the basic assist and damping, the steering feel is stable during high-speed driving, significantly reducing the problem of excessive steering sensitivity caused by the steering wheel being too light, avoiding uncontrollable swinging of the vehicle trajectory, especially the bend compensation assist, which allows the driver to retain clear road feel at low speed and fully intervene in compensation at high speed. This not only ensures the intuitiveness of low-speed control, but also ensures high-speed stability, thereby improving safety during turning.

Description

Technical Field

[0001] This application relates to the field of automatic control technology, and more specifically, to a steering assist control method and device for large new energy vehicles. Background Technology

[0002] Most vehicles nowadays have a power steering system, which provides steering torque to make it easier for the driver to turn.

[0003] Currently, power steering systems generally provide a fixed steering assist torque. However, for heavier vehicles, only a small amount of steering assist torque is needed under certain driving conditions. If a fixed steering assist torque is provided, the steering will become unusually agile. On the other hand, for heavier vehicles, a large amount of steering assist torque is needed under certain driving conditions. If a fixed steering assist torque is provided, the steering will become relatively difficult, resulting in a mismatch between steering force and steering effort, which will prevent precise steering. In either case, safety during steering will be reduced. Summary of the Invention

[0004] In view of this, embodiments of this application provide a steering assist control method and device for large new energy vehicles to improve vehicle safety during steering.

[0005] In a first aspect, embodiments of this application provide a steering assist control method for large new energy vehicles, the method comprising:

[0006] Get the vehicle's current speed Steering wheel torque Steering wheel speed ,gross weight lateral acceleration ;

[0007] According to speed And the preset maximum assist torque gain during low-speed movement. The preset minimum assist torque gain during high-speed motion Determine the speed The boost torque gain provided by the lower power steering system ;

[0008] According to speed And the preset assist saturation torque during low-speed movement Preset assist saturation torque during high-speed motion Determine the speed The saturation torque provided by the lower steering assist system ;

[0009] According to steering wheel torque Boost torque gain and saturation torque Calculate the speed The basic assist torque provided by the lower steering assist system ;

[0010] Based on total weight and empty vehicle weight Calculate the compensation torque coefficient of the power steering system under the current load of the vehicle. ;

[0011] According to speed Steering wheel speed And the preset maximum damping torque during low-speed motion. and the preset minimum damping torque during high-speed motion Determine the speed Damping torque of the lower steering assist system ;

[0012] According to speed lateral acceleration ,gross weight Calculate the vehicle's speed The cornering compensation torque coefficient provided by the power steering system when cornering out of a corner ;

[0013] Use the compensation torque coefficient Basic assist torque Compensation is performed using damping torque. and cornering compensation assist torque coefficient The compensated base assist torque is corrected to obtain the assist torque that the power steering system currently needs to provide. ;

[0014] According to the assist torque Control the power steering system.

[0015] Secondly, embodiments of this application provide a steering assist control device for large new energy vehicles, the steering assist control device comprising:

[0016] The acquisition unit is used to acquire the current speed of the vehicle. Steering wheel torque Steering wheel speed ,gross weight lateral acceleration ;

[0017] The first calculation unit is used to calculate based on speed. and a preset maximum boost torque gain at a low speed motion , a preset minimum boost torque gain at a high speed motion , a boost torque gain provided by the steering boost system at a speed ;

[0018] a second calculation unit configured to determine a saturation torque provided by the steering boost system at a speed , and a preset boost saturation torque at a low speed motion , a preset boost saturation torque at a high speed motion , a speed ;

[0019] a third calculation unit configured to calculate a base boost torque provided by the steering boost system at a speed , the boost torque gain , and the saturation torque ;

[0020] a fourth calculation unit configured to calculate a compensation torque coefficient of the steering boost system at a current load of the vehicle according to a total weight , and an empty vehicle weight ;

[0021] a fifth calculation unit configured to determine a damping torque of the steering boost system at a speed , a steering wheel rotation speed , and a preset maximum damping torque at a low speed motion , and a preset minimum damping torque at a high speed motion , a speed ;

[0022] a sixth calculation unit configured to calculate a cornering compensation boost torque coefficient provided by the steering boost system at a speed , a lateral acceleration , and a total weight , a speed ;

[0023] a seventh calculation unit configured to compensate the base boost torque using the compensation torque coefficient , the damping torque , and the cornering compensation boost torque coefficient ​​​​​​​The compensated basic assist torque is corrected to obtain an assist torque currently required by the steering assist system ;

[0024] The control unit is configured to correct the assist torque The steering assist system is controlled.

[0025] The technical solutions provided in the application include but are not limited to the following beneficial effects:

[0026] In the application, when the vehicle is turning, the current driving parameter of the vehicle is obtained to obtain corresponding compensation data and correction data. Through the compensation torque coefficient and the turning compensation assist torque coefficient, the assist torque can be automatically increased when the vehicle is fully loaded or high-speed turning to offset the increase in the righting moment caused by the surge of the tire vertical load and the lateral force, prevent the driver from operating incorrectly or delaying the reaction due to the sudden weight of the steering wheel at the critical moment (such as emergency obstacle avoidance or high-speed turning), and ensure the stable steering feel during high-speed driving based on the basic assist torque and the damping torque, significantly reduce the problem of excessive sensitivity of steering caused by the steering wheel being too light, and avoid uncontrollable swinging of the vehicle trajectory, especially the turning compensation torque coefficient, which allows the driver to retain clear road feeling at low speed and fully intervene in compensation at high speed. This not only ensures the intuitiveness of low-speed control, but also ensures the stability at high speed, thereby improving the safety during turning.

[0027] In order to make the above-mentioned purposes, features and advantages of the application more obvious and easy to understand, the following preferred embodiments are described in detail below, and the accompanying drawings are described as follows. BRIEF DESCRIPTION OF DRAWINGS

[0028] In order to more clearly illustrate the technical solutions of the embodiments of the application, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only show some embodiments of the application, and therefore should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can also be obtained without creative labor on the basis of these drawings.

[0029] Figure 1 A flowchart of a steering assist control method for large new energy vehicles provided by the embodiments of the application is shown.

[0030] Figure 2 A structural diagram of a steering assist control device for large new energy vehicles provided by the embodiments of the application is shown. DETAILED DESCRIPTION

[0031] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely represents selected embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0032] Large new energy vehicles are equipped with relatively fast processors, providing a platform for dynamic compensation. They also feature a variety of sensors that can acquire various parameters of the vehicle in real time during operation, such as its current speed. Steering wheel torque Steering wheel speed ,gross weight and lateral acceleration These driving parameters provide data support for dynamic compensation.

[0033] Figure 1 This application provides a flowchart illustrating a steering assist control method for large new energy vehicles, as shown in the embodiments below. Figure 1 As shown, the method includes the following steps:

[0034] Step 101: Obtain the vehicle's current speed Steering wheel torque Steering wheel speed ,gross weight lateral acceleration ;

[0035] Step 102, based on speed And the preset maximum assist torque gain during low-speed movement. The preset minimum assist torque gain during high-speed motion Determine the speed The boost torque gain provided by the lower power steering system .

[0036] Step 103, based on speed And the preset assist saturation torque during low-speed movement Preset assist saturation torque during high-speed motion Determine the speed Saturation torque provided by the steering assist system .

[0037] Step 104, the base assist torque provided by the steering assist system at the speed , the assist torque gain and the saturation torque are calculated according to the steering wheel torque . .

[0038] Step 105, the compensation torque coefficient of the steering assist system at the current load of the vehicle is calculated according to the total weight and the empty vehicle weight . .

[0039] Step 106, the damping torque of the steering assist system at the speed is determined according to the speed , the steering wheel rotation speed , the preset maximum damping torque during low-speed movement and the preset minimum damping torque during high-speed movement . .

[0040] Step 107, the over-bend compensation assist torque coefficient provided by the steering assist system when the vehicle is over-bending at the speed is calculated according to the speed , the lateral acceleration , the total weight . .

[0041] Step 108, the base assist torque is compensated using the compensation torque coefficient , and the compensated base assist torque is corrected using the damping torque and the over-bend compensation assist torque coefficient to obtain the assist torque currently required by the steering assist system .

[0042] Step 109, the steering assist system is controlled according to the assist torque .

[0043] Specifically, the assist torque required during the turning process is different at different speeds, the assist torque gain determines the ease of turning, and the assist torque gain Essentially, it's the torque amplification factor. A higher gain makes steering easier, as the power steering system provides a large amount of assist torque, making the steering feel very light and easy for the driver. A lower gain requires more effort to achieve noticeable assist torque, making the steering feel very stable. Furthermore, different speeds require different steering feels—for example, a stable feel at high speeds and a light feel at low speeds. Therefore, to determine the appropriate torque amplification factor, it's necessary to use a pre-set maximum torque amplification factor for low-speed driving. The preset minimum assist torque gain during high-speed motion And the current speed is determined at the speed The boost torque gain provided by the lower power steering system To achieve increased torque at low speeds Need to increase the torque of the smaller steering wheel This allows for greater power assist torque, resulting in lighter steering; at high speeds, the power assist torque gain... It needs to be reduced, and more steering wheel torque is required. Only in this way can the same assist torque be obtained, the feel becomes heavier, thus giving the driver a better cornering feel.

[0044] Saturated torque This determines the maximum assist torque that the power steering system can provide, and the saturation torque. A higher torque means that even with heavy steering, the power assist torque will continue to increase linearly, providing strong and continuous assistance. (Saturation torque) A low torque level means the assist torque will quickly reach its limit, and no matter how much force you apply, the assist torque will not increase further. This preserves more road feedback and prevents a "false lightness" feel, adjusting according to the current speed. And the preset assist saturation torque during low-speed movement Preset assist saturation torque during high-speed motion To determine the appropriate saturation torque for the current speed V. This allows the driver to obtain a relatively suitable assist torque.

[0045] After obtaining the boost torque gain and saturation torque After that, it is necessary to combine the steering wheel torque. Calculation speed The basic assist torque provided by the lower steering assist system To avoid sudden changes in feel.

[0046] When a vehicle is carrying a load, the required assistance needs to be increased, therefore it can be adjusted based on the total weight. and empty vehicle weight The compensation torque coefficient of the power steering system is obtained. This affects the basic assist torque. Compensation is made to accommodate the current total weight of the vehicle.

[0047] To suppress unnecessary rapid turning, a system needs to be provided that is synchronized with the steering wheel rotation speed. Conversely, damping torque primarily functions to suppress excessive lightness and vibration of the steering wheel when the vehicle is stationary, and to address the sluggishness of the engine speed at high speeds, thus requiring consideration of speed. Steering wheel speed And the preset maximum damping torque during low-speed motion. and the preset minimum damping torque during high-speed motion To determine the speed Damping torque of the lower steering assist system This allows us to obtain a damping torque that is appropriate for the current speed.

[0048] Because a self-aligning force occurs when cornering, and this self-aligning force is related to speed... lateral acceleration ,gross weight All of these are relevant; to counteract the self-correcting force during cornering, it is necessary to adjust the speed accordingly. lateral acceleration ,gross weight Calculate the vehicle's speed The cornering compensation torque coefficient provided by the power steering system when cornering out of a corner This is to counteract unpredictable torque changes at high speeds and improve stability.

[0049] After obtaining the compensation torque coefficient Damping torque and cornering compensation assist torque coefficient Then, by compensating for the torque coefficient Basic assist torque Compensation is performed to obtain the assist torque that adapts to the total weight of the current vehicle, and then the damping torque is applied. and cornering compensation assist torque coefficient The assist torque is adjusted to obtain an assist torque that is suitable for the current cornering situation. This makes the driver's turning feel relatively suitable.

[0050] In the present application, when the vehicle is turning, the current driving parameters of the vehicle are obtained to obtain corresponding compensation data and correction data. Through the compensation torque coefficient and the over-turning compensation boost torque coefficient, the boost torque can be automatically increased when the vehicle is fully loaded or high-speed over-turning to offset the increase of the righting moment caused by the vertical load and lateral force of the tire, so as to prevent the driver from operating incorrectly or delaying the reaction due to the sudden weight of the steering wheel in critical moments (such as emergency obstacle avoidance or high-speed over-turning). Based on the basic boost torque and the damping torque, the steering feel is stable during high-speed driving, which significantly reduces the problem of over-sensitive steering caused by the too light steering wheel, avoids uncontrollable swinging of the vehicle trajectory, and especially the over-turning compensation torque coefficient. The driver retains clear road feeling at low speed, and fully intervenes in compensation at high speed, which not only ensures the intuitiveness of low-speed operation, but also ensures the stability at high speed, thereby improving the safety during turning.

[0051] It should be noted that when controlling the steering boost system, the control of the steering boost system can be realized by controlling the current size or the opening degree of the steering valve, so that the boost torque provided by the steering boost system is The specific control strategy can be set according to the type of actual steering boost system, and is not limited here.

[0052] It should be noted that the total weight of the vehicle generally does not change during driving, so the compensation torque coefficient only needs to be calculated once and stored. When the compensation torque coefficient is needed for compensation during the current driving process, the stored data can be retrieved.

[0053] It should be noted again that the sensors in the vehicle are usually collected at a certain frequency, and when the steering boost system is controlled between two collection periods, the boost torque calculated using the data collected in the earlier collection period of the two collection periods is controlled. .

[0054] In a feasible implementation, when step 102 is performed, the boost torque gain is calculated using formula one as follows: :

[0055] ; formula one

[0056] wherein, is a preset speed threshold for distinguishing high-speed motion and low-speed motion, represents a hyperbolic tangent function.

[0057] Specifically, can be set to 50 km / h, and when higher than high speed motion, when below low speed motion, corresponding speed is shown in The hyperbolic tangent function is used to achieve a smooth transition of the parameters with the vehicle speed, avoiding abrupt changes in the feel.

[0058] In one possible implementation, when performing step 103, the saturated torque is calculated using the following equation two :

[0059] Equation two

[0060] In one possible implementation, when performing step 104, the base assist torque is calculated using the following equation three :

[0061] Equation three

[0062] wherein, is a shape factor of the preset base assist torque and the preset steering wheel torque growth curve, and is equal to 2.

[0063] In one possible implementation, when performing step 105, the compensation torque coefficient is calculated using the following equation four :

[0064] Equation four

[0065] wherein, is a nonlinear factor representing a nonlinear relationship between the increase of the vehicle steering resistance and the increase of the vehicle load, and is a positive number less than 1, is a preset load compensation coefficient of the vehicle, wherein, the value of is in the range of 0.2-0.8.

[0066] In one possible implementation, when performing step 106, the damping torque is calculated using the following equation five :

[0067] Equation five

[0068] wherein, exp is an exponential decay function, represents the rate of the control damping decay with the vehicle speed, and is in the range of 30 km / h to 50 km / h.

[0069] Specifically, the negative sign in equation five indicates that the damping force always hinders the motion direction, is an equivalent damping torque coefficient, which is a quantity varying with the vehicle speed, and the damping torque coefficient is Its main function is to suppress excessive lightness and vibration of the steering wheel when the vehicle is stationary. As the vehicle speed V increases, this value decreases sharply to 0, and the damping torque coefficient becomes... This reduces damping torque at high speeds, ensuring a stable feel while preventing a sticky sensation. The smaller the value, the faster the decay.

[0070] In one feasible implementation, when performing step 107, the cornering compensation assist torque coefficient is calculated using the following formula six. :

[0071]

[0072] Formula Six

[0073] in, Indicates the direction of lateral acceleration. The preset compensation rate as a function of lateral acceleration is 0.5 m / s². 2 Up to 3.0 m / s 2 , This is a preset speed constant, ranging from 0.02 to 0.1, with units equal to speed. same, The preset gain constant for cornering compensation is 0.001 kg. 1 Up to 0.01kg 1 .

[0074] Specifically, Ensure the direction of the compensation distance is consistent with the turning direction; the return torque is closely related to the total mass. It is a smooth saturation function that describes the compensation amount as a function of lateral acceleration. The relationship of increasing The smaller the value, the greater the compensation. The faster it increases, This refers to speed-related compensation gain. During low-speed, large-angle steering, the significant self-centering torque is a crucial road feel that the driver expects to experience. Compensating for this gain would result in an unnatural driving feel, therefore it is necessary to... , This means that the system provides almost no cornering compensation when making a U-turn at low speeds. At high speeds... This means that full compensation needs to be provided to offset unpredictable torque changes at high speeds and improve stability.

[0075] In one feasible implementation, when performing step 108, the assist is calculated using the following formula seven. :

[0076] Equation seven.

[0077] Specifically, the basic assistance torque is the skeleton of the entire assistance system, establishes the touch base tone, and compensates the torque coefficient is used to correct the basic assistance torque, and the damping torque is used to suppress jitter, improve stability, and compensate the assistance torque coefficient when turning is used to offset the change in return moment, and the assistance torque of the vehicle at the current turning time can be obtained through equation seven.

[0078] In a feasible embodiment, the large new energy vehicle includes a new energy passenger vehicle and a new energy truck.

[0079] It should be noted that the present application can also be adapted to other large new energy vehicles, such as new energy mine vehicles, new energy tanks, etc., and the specific use scenarios can be set according to actual needs, which are not limited here.

[0080] Figure 2 A structure diagram of a steering assistance control device for a large new energy vehicle provided by the embodiment of the present application is shown in Figure 2 The steering assistance control device includes:

[0081] The acquisition unit 21 is configured to acquire the current speed , steering wheel torque , steering wheel speed , total weight , and lateral acceleration of the vehicle.

[0082] The first calculation unit 22 is configured to determine the assistance torque gain provided by the steering assistance system at the speed according to the speed , and the preset maximum assistance torque gain during low-speed movement , and the preset minimum assistance torque gain during high-speed movement .

[0083] The second calculation unit 23 is configured to determine the saturation torque provided by the steering assistance system at the speed according to the speed , and the preset assistance saturation torque during low-speed movement , and the preset assistance saturation torque during high-speed movement .

[0084] The third calculation unit 24 is configured to determine the assistance torque according to the steering wheel torque , and the assistance torque gain ​​and saturation torque Calculate the speed The basic assist torque provided by the lower steering assist system ;

[0085] The fourth calculation unit 25 is used to calculate based on the total weight. and empty vehicle weight Calculate the compensation torque coefficient of the power steering system under the current load of the vehicle. ;

[0086] The fifth calculation unit 26 is used to calculate based on speed. Steering wheel speed And the preset maximum damping during low-speed motion. and the preset minimum damping torque during high-speed motion Determine the speed Damping torque of the lower steering assist system ;

[0087] The sixth calculation unit 27 is used to calculate based on speed. lateral acceleration ,gross weight Calculate the vehicle's speed The cornering compensation torque coefficient provided by the power steering system when cornering out of a corner ;

[0088] The seventh calculation unit 28 is used to calculate the compensation torque coefficient. Basic assist torque To compensate, use damping torque. and cornering compensation assist torque coefficient The compensated base assist torque is corrected to obtain the assist torque that the power steering system currently needs to provide. ;

[0089] Control unit 29, used to adjust the assist torque according to the torque. Control the power steering system.

[0090] In one feasible implementation, the first computing unit is used to calculate based on speed. And the preset maximum assist torque gain during low-speed movement. The preset minimum assist torque gain during high-speed motion Determine the speed The boost torque gain provided by the lower power steering system At that time, including:

[0091] Calculate the boost torque gain using the following formula :

[0092] ;

[0093] in, The preset speed threshold for distinguishing between high-speed and low-speed motion, This represents the hyperbolic tangent function.

[0094] In one feasible implementation, the second computing unit is used to calculate based on speed. And the preset assist saturation torque during low-speed movement Preset assist saturation torque during high-speed motion Determine the speed Saturation torque provided by the lower steering assist system At that time, including:

[0095] Calculate the saturation torque using the following formula :

[0096] .

[0097] In one feasible implementation, the third calculation unit is used to calculate based on the steering wheel torque. Boost torque gain and saturation torque Calculate the speed The basic assist torque provided by the lower steering assist system At that time, including:

[0098] Calculate the base assist torque using the following formula :

[0099] ;

[0100] in, The shape factor for the preset base assist torque and preset steering wheel torque growth curve is set to 2.

[0101] In one feasible implementation, the fourth calculation unit is used to calculate based on the total weight. and empty vehicle weight Calculate the compensation torque coefficient of the power steering system under the current load of the vehicle. At that time, including:

[0102] The compensation torque coefficient is calculated using the following formula. :

[0103] ;

[0104] in, a non-linear factor for representing the non-linear relationship between the increase of the steering resistance of the vehicle and the increase of the load of the vehicle, being a positive number less than 1, a load compensation coefficient preset for the vehicle.

[0105] In a feasible embodiment, the fifth calculation unit is configured to determine the damping torque of the steering assist system at a speed , a steering wheel rotation speed , a preset maximum damping torque at a low speed movement , and a preset minimum damping torque at a high speed movement , including: The damping torque is calculated by the following formula:

[0106]

[0107] ;

[0108] wherein exp is an exponential decay function, indicating the rate of the control damping decay with the speed, and the value range is 30 km / h to 50 km / h.

[0109] In a feasible embodiment, the sixth calculation unit is configured to calculate the over-bend compensation assist force provided by the steering assist system when the vehicle is over-bending at a speed , a lateral acceleration , and a total weight , including: The over-bend compensation assist force torque coefficient is calculated by the following formula:

[0110]

[0111]

[0112] ;

[0113] wherein indicates the direction of the lateral acceleration, is a preset compensation rate increasing with the lateral acceleration, and the value range is 0.5 m / s 2 to 3.0 m / s 2 , is a preset rate constant, and the value range is 0.02 to 0.1, and the unit is the same as the speed , is a preset over-bend compensation base gain constant 0.001 kg 1 to 0.01 kg​​​​​​ 1 .

[0114] In one feasible implementation, the seventh calculation unit is used to use the compensated torque coefficient. Basic assist torque Compensation is performed using damping torque. and cornering compensation assist torque coefficient The compensated base assist torque is corrected to obtain the assist that the power steering system currently needs to provide. At that time, including:

[0115] Calculate the assist torque using the following formula :

[0116] .

[0117] In one feasible implementation plan, large new energy vehicles include new energy customers and new energy trucks.

[0118] about Figure 2 For explanations of the relevant principles, please refer to [link / reference]. Figure 1 Detailed explanations of the relevant content will not be repeated here.

[0119] In the embodiments provided in this application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. The apparatus embodiments described above are merely illustrative. For example, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. Furthermore, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Additionally, the displayed or discussed mutual couplings, direct couplings, or communication connections may be through some communication interfaces; indirect couplings or communication connections between devices or units may be electrical, mechanical, or other forms.

[0120] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0121] In addition, the functional units in the embodiments provided in this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0122] If the functions are implemented 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 essentially or the parts that contribute to the prior art or parts of the technical solutions can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes a number of 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, Read-Only Memory), a random access memory (RAM, Random Access Memory), a magnetic disk or an optical disk, and various program code storage media.

[0123] It should be noted that similar reference numbers and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings. In addition, the terms "first", "second", "third" and the like are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0124] Finally, it should be noted that the above-described embodiments are only specific implementations of the present application, which are used to illustrate the technical solutions of the present application, but not to limit them. The protection scope of the present application is not limited thereto. Although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any person skilled in the art can modify or easily think of changes to the technical solutions described in the foregoing embodiments within the technical scope disclosed by the present application, or make equivalent replacements to some of the technical features. These modifications, changes or replacements do not cause the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present application. They should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A steering assist control method for a large new energy vehicle, characterized by, The method comprises: acquiring a current speed of the vehicle steering wheel torque steering wheel rotational speed total weight lateral acceleration ; According to the speed , and a preset maximum boost torque gain at low speed motion , a preset minimum boost torque gain at high speed motion , determine the boost torque gain provided by the steering boost system at the speed ;​ According to the speed , and the preset low-speed motion time assist saturation torque , the preset high-speed motion time assist saturation torque , determine the saturation torque provided by the steering assist system at the speed ;​ According to the steering wheel torque , a boost torque gain and a saturation torque , a base boost torque provided by the steering boost system at a speed is calculated; According to the total weight and the empty weight , the compensation torque coefficient of the steering assist system of the vehicle under the current load is calculated ; According to the speed , the steering wheel rotation speed , and the preset maximum damping torque at low speed movement and the preset minimum damping torque at high speed movement , the damping torque of the steering assist system at the speed is determined ; According to the speed , the lateral acceleration , the total weight , the over-bend compensation boost torque coefficient provided by the over-bend compensation boost system of the vehicle when the vehicle is over-bending at the speed is calculated ; Using a compensation torque coefficient to the base assistance torque Using a damping torque and an over-bank compensation assistance torque coefficient correcting the compensated base assistance torque to obtain the assistance torque currently required by the steering assistance system ; According to the assist torque The steering assist system is controlled.

2. The steering assist control method according to claim 1, characterized by, According to speed And the preset maximum assist torque gain during low-speed movement. The preset minimum assist torque gain during high-speed motion Determine the speed The boost torque gain provided by the lower power steering system ,include: The boost torque gain is calculated using the following equation : ； wherein is a predetermined velocity threshold value for distinguishing between high-speed motion and low-speed motion, denotes the hyperbolic tangent function.

3. The steering assist control method according to claim 1, characterized by, The speed , and the preset low-speed motion time assist saturation torque , the preset high-speed motion time assist saturation torque , determine the saturation torque provided by the steering assist system at the speed , comprising:​ The saturation torque is calculated using the following equation : 。 4. The steering assist control method according to claim 1, characterized by, The method based on steering wheel torque Boost torque gain and saturation torque Calculate the speed The basic assist torque provided by the lower steering assist system ,include: The base assist torque is calculated using the following equation : ； wherein is a shape factor of the curve of the preset basic assistance torque and the preset steering wheel torque increase, and is 2.

5. The steering assist control method according to claim 1, characterized by, said total weight and the empty vehicle weight calculating a compensation torque coefficient of the steering assistance system of the vehicle at the current load comprising: The compensation torque coefficient is calculated using the following equation : ； wherein, is a non-linear factor representing a non-linear relationship between an increase in the steering resistance of the vehicle and an increase in the load of the vehicle, is a positive number smaller than 1, is a load compensation coefficient preset for the vehicle.

6. The steering assist control method of claim 1, wherein, The speed , steering wheel rotation speed , and preset maximum damping torque at low speed movement and preset minimum damping torque at high speed movement , determine the damping torque of the steering assist system at the speed , comprising:​ The damping torque is calculated using the following equation : ； where exp is an exponential decay function, represents the rate of control damping decay with vehicle speed, with a value range of 30 km / h to 50 km / h.

7. The steering assist control method of claim 1, wherein, According to speed lateral acceleration ,gross weight Calculate the vehicle's speed The cornering compensation torque coefficient provided by the power steering system when cornering out of a corner ,include: The over-bend compensation assist torque coefficient is calculated using the following equation : ； wherein, represents the direction of lateral acceleration, is a preset compensation rate for the growth of lateral acceleration, with a value range of 0.5 m / s 2 to 3.0 m / s 2 , is a preset rate constant, with a value range of 0.02 to 0.1, and the unit is the same as the speed , is a preset basic gain constant of over-bending compensation 0.001 kg 1 to 0.01 kg 1 .

8. The steering assist control method of claim 1, wherein, The use of a compensation torque coefficient to the base assistance torque is compensated for, using a damping torque and an over-bend compensation assistance torque coefficient to the compensated base assistance torque, to obtain the assistance torque currently required by the steering assistance system , comprising: The assist torque is calculated using the following equation : 。 9. The steering assist control method of claim 1, wherein, The large new energy vehicle includes a new energy client and a new energy truck.

10. A steering assist control device for a large new energy vehicle, characterized by, The steering assist control device comprises: an acquisition unit configured to acquire a current speed of the vehicle steering wheel torque steering wheel rotational speed total weight lateral acceleration ; The first calculation unit is used to calculate based on speed. And the preset maximum assist torque gain during low-speed movement. The preset minimum assist torque gain during high-speed motion Determine the speed The boost torque gain provided by the lower power steering system ; a second calculation unit configured to determine a saturation torque provided by the steering assistance system at a speed and a preset low-speed motion assistance saturation torque , a preset high-speed motion assistance saturation torque at a speed ;​ The third calculation unit is used to calculate based on the steering wheel torque. Boost torque gain and saturation torque Calculate the speed The basic assist torque provided by the lower steering assist system ; a fourth calculation unit configured to calculate a compensation torque coefficient of the steering assist system of the vehicle at the current load based on the total weight and the empty vehicle weight ​​ a fifth computing unit for determining a damping torque of the steering assist system at a speed , a steering wheel rotational speed , and a maximum damping torque preset for a low speed motion and a minimum damping torque preset for a high speed motion , wherein the speed is determined from the steering wheel rotational speed . The sixth calculation unit is used to calculate based on speed. lateral acceleration ,gross weight Calculate the vehicle's speed The cornering compensation torque coefficient provided by the power steering system when cornering out of a corner ; a seventh calculation unit for using a compensation torque coefficient to the base assistance torque a damping torque and an over-bend compensation assistance torque coefficient correcting the compensated base assistance torque to obtain an assistance torque currently required to be provided by the steering assistance system ; a control unit for controlling the assist torque The steering assist system is controlled.

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