Steering control method, device and vehicle

Abstract

The present application discloses a steering control method, device and vehicle, belonging to the field of vehicle technology. It includes: in the case of a failure of the electric power steering system of the target vehicle, obtaining the current speed, target steering wheel angle, current steering wheel angle and current steering wheel torque of the target vehicle; determining the rear wheel angle gain based on the current steering wheel torque and the initial angle difference based on the current speed, target steering wheel angle and current steering wheel angle of the target vehicle, the rear wheel angle gain is used to indicate the urgency of the driver's steering; based on the rear wheel angle gain and the initial angle difference of the target vehicle, the target vehicle is controlled to adjust the rear wheel angle. The present application determines a rear wheel angle that meets the driver's steering needs, so that adjusting the rear wheel angle can provide steering assistance to the driver, so that the vehicle can maintain the original driving trajectory, avoid the driver's nervousness, and is conducive to driving safety.

Description

Technical Field

[0001] The present application relates to the field of vehicle technology, and in particular to a steering control method, device and vehicle. Background Art

[0002] With the development of technology, more and more functions are set on vehicles in order to improve the user's driving experience. At present, there are many assisted driving functions on vehicles, such as lane change assistance, lane keeping function, electric power steering system and other intelligent driving functions. Among them, the electric power steering system is a power system that uses a motor to assist the driver in controlling the steering wheel. It can provide steering assistance to the driver in scenes such as turning and U-turns.

[0003] However, when the electric power steering system of a vehicle has not been repaired for a long time, it is very likely to malfunction during driving. When the electric power steering system suddenly fails, the motor cannot assist the driver in controlling the steering wheel. At this time, if the driver is in a turning scene such as turning or U-turn, the steering wheel will suddenly rebound to the middle. In order to ensure smooth U-turns and turns, the driver needs to rely on his own strength to maintain the steering of the vehicle. In this way, when turning at a large angle on a complex road, if the vehicle cannot turn in time, it may also cause the driver's nervousness, which is not conducive to driving safety. Summary of the invention

[0004] The present application provides a steering control method, device, vehicle and storage medium, which can adjust the rear wheel steering angle of the vehicle to assist the driver in steering when the electric power steering system of the vehicle fails, thereby avoiding the driver's emotional tension and ensuring driving safety. The technical solution is as follows.

[0005] In a first aspect, a steering control method is provided, the method comprising:

[0006] In the case that the electric power steering system of the target vehicle fails, obtaining the current vehicle speed, target steering wheel angle, current steering wheel angle and current steering wheel torque of the target vehicle, wherein the target steering wheel angle is the steering wheel angle at a moment before the electric power steering system of the target vehicle fails;

[0007] Based on the current steering wheel torque, determine a rear wheel steering angle gain and based on the current vehicle speed, target steering wheel angle and current steering wheel angle, determine an initial steering angle difference, wherein the rear wheel steering angle gain is used to indicate the urgency of the driver when steering, and the initial steering angle difference is a theoretical angle required for the rear wheels of the target vehicle to rotate at the current vehicle speed;

[0008] Based on the rear wheel steering angle gain of the target vehicle and the initial steering angle difference, the target vehicle is controlled to adjust the rear wheel steering angle.

[0009] In the present application, when the electric power steering system of the target vehicle fails, the current speed, target steering wheel angle, current steering wheel angle and current steering wheel torque of the target vehicle are first obtained, and then the rear wheel angle gain is determined based on the current steering wheel torque, and the initial angle difference is determined based on the current speed, the target steering wheel angle at the previous moment when the electric power steering system fails, and the current steering wheel angle when the electric system fails, that is, the urgency of the driver's steering and the theoretical angle that the rear wheels of a target vehicle need to rotate at the current speed are first determined. Then, based on the rear wheel angle gain of the target vehicle and the initial angle difference, the target vehicle is controlled to adjust the rear wheel angle. The rear wheel angle gain can know the urgency of the driver's steering, and thus it can be known whether the rear wheel angle should be larger or smaller. In this way, a rear wheel steering angle that can meet the driver's steering needs can be determined based on the rear wheel steering gain and the initial steering angle difference. The driver's steering is then assisted by adjusting the rear wheel steering angle, so that the vehicle can maintain its original driving trajectory, thereby avoiding the driver's nervousness and facilitating driving safety.

[0010] Optionally, controlling the target vehicle to adjust the rear wheel steering angle based on the rear wheel steering angle gain of the target vehicle and the initial steering angle difference includes:

[0011] Multiplying the rear wheel steering angle gain by the initial steering angle difference to obtain a target rear wheel steering angle;

[0012] The rear wheels of the target vehicle are controlled to rotate to the target rear wheel turning angle.

[0013] Optionally, determining the initial steering angle difference based on the current vehicle speed, the target steering wheel angle, and the current steering wheel angle of the target vehicle includes:

[0014] Subtracting the target steering wheel angle from the current steering wheel angle to obtain a steering wheel angle difference;

[0015] Based on the steering wheel angle difference and the current vehicle speed, a corresponding initial angle difference is obtained from a target correspondence relationship.

[0016] Optionally, before determining the initial steering angle difference based on the current vehicle speed, the target steering wheel angle and the current steering wheel angle of the target vehicle, the method further includes:

[0017] Obtaining the target vehicle speed and target heading angle at a moment before the electric power steering system of the target vehicle fails, the wheelbase and gear ratio of the target vehicle, and the current heading angle;

[0018] Optionally, determining the initial steering angle difference based on the current vehicle speed, the target steering wheel angle, and the current steering wheel angle of the target vehicle includes:

[0019] An initial steering angle difference is determined based on the current vehicle speed of the target vehicle, the target vehicle speed, the wheelbase, the gear ratio, the current heading angle, the target steering wheel angle, the target heading angle, and the current steering wheel angle.

[0020] Optionally, determining the initial steering angle difference based on the current vehicle speed of the target vehicle, the target vehicle speed, the wheelbase, the gear ratio, the current heading angle, the target steering wheel angle, the target heading angle, and the current steering wheel angle includes:

[0021] Predicting a first driving trajectory of the target vehicle before an electric power steering system fails based on the wheelbase and the gear ratio of the target vehicle, the target heading angle, the target vehicle speed, and the target steering wheel angle;

[0022] Predicting a second driving trajectory of the target vehicle after a failure of an electric power steering system occurs based on the wheelbase and the gear ratio of the target vehicle, the current heading angle, the current vehicle speed, and the current steering wheel angle;

[0023] The initial turning angle difference is determined based on the first driving trajectory, the second driving trajectory, and the wheelbase.

[0024] Optionally, predicting a first driving trajectory of the target vehicle before an electric power steering system fails based on the wheelbase and the gear ratio of the target vehicle, the target heading angle, the target vehicle speed, and the target steering wheel angle includes:

[0025] Dividing the target steering wheel angle by the gear ratio to obtain a target front wheel angle, wherein the target front wheel angle is the front wheel angle of the target vehicle at a moment before the electric power steering system fails;

[0026] Determining a target angular velocity of the target vehicle based on the target front wheel steering angle, the target vehicle speed, and the wheelbase;

[0027] Based on the target angular velocity and the target heading angle, updating the position of the target vehicle at multiple times with the current position of the target vehicle as the initial position;

[0028] The positions of the target vehicle at multiple times are fitted to obtain the first driving trajectory.

[0029] Optionally, determining the initial steering angle difference based on the first driving trajectory, the second driving trajectory, the current steering wheel angle, and the wheelbase includes:

[0030] Determining a first turning radius of the target vehicle based on the first driving trajectory, and determining a second turning radius of the target vehicle based on the second driving trajectory;

[0031] determining a target radius difference based on the first turning radius and the second turning radius;

[0032] An initial turning angle difference is determined based on the target radius difference and the wheelbase.

[0033] Optionally, after controlling the target vehicle to adjust the rear wheel steering angle based on the rear wheel steering angle gain of the target vehicle and the initial steering angle difference, the method further includes:

[0034] Determining the driver's driving intention based on the road information of the target vehicle and the current steering wheel angle;

[0035] In the case where the driving intention is to turn, determining a recommended driving trajectory of the target vehicle based on the road information, wherein the recommended driving trajectory is a driving trajectory that enables the target vehicle to turn smoothly;

[0036] Based on the current steering wheel angle, the adjusted rear wheel angle, the wheelbase and the current vehicle speed of the target vehicle, predict a third driving trajectory, where the third driving trajectory is the driving trajectory of the target vehicle after the rear wheel angle is adjusted;

[0037] The target vehicle is controlled to project the suggested driving trajectory and the third driving trajectory.

[0038] In a second aspect, a steering control device is provided, the device comprising:

[0039] A first acquisition module is used to acquire the current vehicle speed, target steering wheel angle, current steering wheel angle and current steering wheel torque of the target vehicle when the electric power steering system of the target vehicle fails, wherein the target steering wheel angle is the steering wheel angle at a moment before the electric power steering system of the target vehicle fails;

[0040] A first determination module is used to determine a rear wheel steering angle gain based on the current steering wheel torque and an initial steering angle difference based on the current vehicle speed, the target steering wheel angle and the current steering wheel angle of the target vehicle, wherein the rear wheel steering angle gain is used to indicate the urgency of the driver when steering, and the initial steering angle difference is a theoretical angle required for the rear wheels of the target vehicle to rotate at the current vehicle speed;

[0041] The control module is used to control the target vehicle to adjust the rear wheel steering angle based on the rear wheel steering angle gain of the target vehicle and the initial steering angle difference.

[0042] Optionally, the control module is used to:

[0043] Multiplying the rear wheel steering angle gain by the initial steering angle difference to obtain a target rear wheel steering angle;

[0044] The rear wheels of the target vehicle are controlled to rotate to the target rear wheel turning angle.

[0045] Optionally, the first determining module is used to:

[0046] Subtracting the target steering wheel angle from the current steering wheel angle to obtain a steering wheel angle difference;

[0047] Based on the steering wheel angle difference and the current vehicle speed, a corresponding initial angle difference is obtained from a target correspondence relationship.

[0048] Optionally, the device further comprises:

[0049] A second acquisition module is used to acquire the target vehicle speed and target heading angle at a previous moment when the electric power steering system of the target vehicle fails, the wheelbase and gear ratio of the target vehicle, and the current heading angle;

[0050] Optionally, the first determining module is used to:

[0051] An initial steering angle difference is determined based on the current vehicle speed of the target vehicle, the target vehicle speed, the wheelbase, the gear ratio, the current heading angle, the target steering wheel angle, the target heading angle, and the current steering wheel angle.

[0052] Optionally, the first determining module is used to:

[0053] Predicting a first driving trajectory of the target vehicle before an electric power steering system fails based on the wheelbase and the gear ratio of the target vehicle, the target heading angle, the target vehicle speed, and the target steering wheel angle;

[0054] Predicting a second driving trajectory of the target vehicle after a failure of an electric power steering system occurs based on the wheelbase and the gear ratio of the target vehicle, the current heading angle, the current vehicle speed, and the current steering wheel angle;

[0055] The initial turning angle difference is determined based on the first driving trajectory, the second driving trajectory, and the wheelbase.

[0056] Optionally, the first determining module is used to:

[0057] Dividing the target steering wheel angle by the gear ratio to obtain a target front wheel angle, wherein the target front wheel angle is the front wheel angle of the target vehicle at a moment before the electric power steering system fails;

[0058] Determining a target angular velocity of the target vehicle based on the target front wheel steering angle, the target vehicle speed, and the wheelbase;

[0059] Based on the target angular velocity and the target heading angle, updating the position of the target vehicle at multiple times with the current position of the target vehicle as the initial position;

[0060] The positions of the target vehicle at multiple times are fitted to obtain the first driving trajectory.

[0061] Optionally, the first determining module is used to:

[0062] Determining a first turning radius of the target vehicle based on the first driving trajectory, and determining a second turning radius of the target vehicle based on the second driving trajectory;

[0063] determining a target radius difference based on the first turning radius and the second turning radius;

[0064] An initial turning angle difference is determined based on the target radius difference and the wheelbase.

[0065] Optionally, the device further comprises:

[0066] A second determination module is used to determine the driver's driving intention based on the road information of the target vehicle and the current steering wheel angle;

[0067] A third determination module is used to determine a recommended driving trajectory of the target vehicle based on the road information when the driving intention is to turn, wherein the recommended driving trajectory is a driving trajectory that enables the target vehicle to turn smoothly;

[0068] A prediction module, configured to predict a third driving trajectory based on the current steering wheel angle, the adjusted rear wheel angle, the wheelbase and the current vehicle speed of the target vehicle, wherein the third driving trajectory is the driving trajectory of the target vehicle after the rear wheel angle is adjusted;

[0069] A projection module is used to control the target vehicle to project the suggested driving trajectory and the third driving trajectory.

[0070] In a third aspect, a vehicle is provided, the vehicle comprising:

[0071] A memory for storing executable program codes;

[0072] The processor is used to call and run the executable program code from the memory so that the vehicle executes the above-mentioned steering control method.

[0073] In a fourth aspect, a computer-readable storage medium is provided, wherein the computer-readable storage medium stores a computer program, and the computer program implements the above-mentioned steering control method when executed by a processor.

[0074] In a fifth aspect, a computer program product comprising instructions is provided, which, when executed on a computer, enables the computer to execute the steps of the above-mentioned steering control method.

[0075] It can be understood that the beneficial effects of the second, third, fourth and fifth aspects mentioned above can be found in the relevant description of the first aspect mentioned above, and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0076] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0077] Figure 1 It is a schematic diagram of an implementation environment of a steering control method provided in an embodiment of the present application;

[0078] Figure 2 is a scenario schematic diagram of a steering control method provided in an embodiment of the present application;

[0079] Figure 3 is a flow chart of a steering control method provided by an embodiment of the present application;

[0080] Figure 4 is a projection schematic diagram of a suggested driving trajectory and a third driving trajectory provided in an embodiment of the present application;

[0081] Figure 5 is a flow chart of another steering control method provided by an embodiment of the present application;

[0082] Figure 6 is a structural schematic diagram of a steering control device provided in an embodiment of the present application;

[0083] Figure 7 It is a structural schematic diagram of a vehicle provided in an embodiment of the present application. DETAILED DESCRIPTION

[0084] In order to make the objectives, technical solutions and advantages of the present application clearer, the implementation methods of the present application will be further described in detail below with reference to the accompanying drawings.

[0085] It should be understood that the "multiple" mentioned in this application refers to two or more. In the description of this application, unless otherwise specified, " / " means or, for example, A / B can mean A or B; "and / or" in this article is only a description of the association relationship of associated objects, indicating that there can be three relationships, for example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. In addition, in order to facilitate the clear description of the technical solution of this application, the words "first" and "second" are used to distinguish between the same items or similar items with basically the same functions and effects. Those skilled in the art can understand that the words "first" and "second" do not limit the quantity and execution order, and the words "first" and "second" do not limit them to be different.

[0086] Before describing the steering control method provided in the embodiment of the present application, the implementation environment of the present application is described first.

[0087] Figure 1 Schematic diagram of an implementation environment of a steering control method provided in an embodiment of the present application. Figure 1 , Figure 1 The vehicle 101 is provided with an electric power steering system 102 (Electric Power Steering, EPS) and a rear wheel steering system 103 .

[0088] The vehicle 101 is a vehicle equipped with the above-mentioned rear-wheel steering system 103. For example, the vehicle 101 can be a front-wheel drive vehicle (Front-Wheel Drive, FWD), a rear-wheel drive vehicle (Rear-Wheel Drive, RWD), or a four-wheel drive vehicle (All-Wheel Drive, AWD). The embodiment of the present application does not limit the type of the vehicle 101.

[0089] The electric power steering system 102 is a power steering system that directly relies on the motor to provide auxiliary torque, which can provide assistance to the driver to reduce the force used in steering. The electric power steering system 102 calculates the required power by detecting the steering wheel angle and the vehicle speed, and then controls the motor to rotate to output the corresponding torque to provide assistance for steering. Generally, when the vehicle is driving at a low speed, especially when the vehicle is turning, the electric power steering system 102 can provide greater assistance, making steering easier.

[0090] The rear-wheel steering system 103 is a technology that can adjust the direction angle of the rear wheels. It improves the handling performance of the vehicle by making the rear wheels of the vehicle rotate in the same direction or opposite direction under certain conditions. The rear-wheel steering system 103 is composed of a rear-wheel steering controller and a wire-controlled steering gear. It receives the steering wheel angle signal, steering wheel speed signal, etc. sent by the vehicle controller through a wire, and then calculates the required rotation angle based on the received steering wheel angle signal, steering wheel speed signal, etc. In general, when the vehicle is driving normally in a straight line, the rear wheels should always remain straight to avoid causing the vehicle to deviate. When the vehicle turns at a low speed, the rear wheels can cooperate with the front wheels to rotate in the opposite direction to reduce the turning radius; when the vehicle changes lanes at high speed, the rear wheels cooperate with the front wheels to rotate in the same direction to improve vehicle stability.

[0091] In an embodiment of the present application, when the electric power steering system 102 in the vehicle 101 fails, the electric power steering system 102 cannot provide steering assistance for the vehicle 101. At this time, the rear wheel steering system 103 can control the rear wheels to rotate a certain angle to assist the driver in steering.

[0092] The application scenarios of the embodiments of the present application are described below.

[0093] For example, Figure 2 is a schematic diagram of a steering control method provided in an embodiment of the present application, see Figure 2 , Figure 2 The vehicle 201 is included in the map, and the vehicle 201 is turning right.

[0094] The process of the vehicle 201 turning right with the assistance of the electric power steering system 102 is as follows: the electric power steering system 102 obtains the steering wheel angle and the current vehicle speed of the vehicle 201. Then, the electric power steering system 102 calculates an angle that the front wheels should turn based on the steering wheel angle and the current vehicle speed, and then the electric power steering system 102 controls the motor to output the corresponding power torque so that the front wheels turn the corresponding angle, thereby assisting the vehicle 201 to turn right when the driver applies a small force.

[0095] However, when the electric power steering system 102 of the vehicle 201 fails, the electric power steering system 102 cannot control the motor to output the corresponding power torque to assist the steering. Therefore, when the electric power steering system fails, the steering wheel will suddenly rebound, and the driving track of the vehicle 201 will also deviate. At this time, the driver needs to rely on greater strength to turn the steering wheel to achieve a large turning angle of the front wheels. If the vehicle cannot turn in time, it may also cause the driver to be nervous, which is not conducive to driving safety.

[0096] To this end, an embodiment of the present application provides a steering control method, which can be applied to a scenario where the vehicle is turning. Of course, the steering control method can also be applied to a scenario where the vehicle is going straight and needs to correct its driving trajectory.

[0097] Specifically, when the electric power steering system 102 of the vehicle 201 fails, the current vehicle speed, current steering wheel angle, current steering wheel torque and the target steering wheel angle of the vehicle 201 at the previous moment when the electric power steering system 102 fails are obtained. Then, the rear wheel angle gain is determined based on the current steering wheel torque. The current steering wheel torque can reflect the magnitude of the force applied by the driver to the steering wheel, so it is equivalent to determining the urgency of the driver's steering based on the current steering wheel torque. And based on the current vehicle speed, the current steering wheel angle and the target steering wheel angle, a theoretical angle required for the rear wheels to rotate at the current vehicle speed is determined. Finally, based on the rear wheel angle gain and the theoretical angle required for the rear wheels to rotate at the current vehicle speed, the vehicle 201 is controlled to adjust the rear wheel angle.

[0098] In this way, a rear wheel steering angle that can meet the driver's steering needs can be determined based on the rear wheel steering gain and the initial steering angle difference. The driver's steering is then assisted by adjusting the rear wheel steering angle, so that the vehicle can maintain its original driving trajectory, thereby avoiding the driver's nervousness and facilitating driving safety.

[0099] The steering control method provided in the embodiment of the present application is explained in detail below.

[0100] Figure 3 is a flow chart of a steering control method provided in an embodiment of the present application. The method can be applied to a vehicle's VCU (Vehicle Control Unit). Figure 3 , the method comprises the following steps.

[0101] Step 301: When an electric power steering system of a target vehicle fails, obtain the current vehicle speed, target steering wheel angle, current steering wheel angle and current steering wheel torque of the target vehicle, where the target steering wheel angle is the steering wheel angle at a moment before the electric power steering system of the target vehicle fails.

[0102] The steering wheel angle refers to the angle at which the steering wheel rotates relative to its initial position when the driver turns the steering wheel. Optionally, an angle sensor may be installed on the steering column of the target vehicle, and the angle sensor may monitor the position change of the steering wheel in real time, so that the target steering wheel angle and the current steering wheel angle may be collected through the angle sensor.

[0103] The current steering wheel torque refers to the torque applied by the driver when turning the steering wheel. This torque reflects the degree of force applied by the driver when operating the steering wheel. Generally, the greater the steering wheel is turned, the greater the steering wheel torque will be, and the steering wheel torque will also be different at different vehicle speeds.

[0104] Optionally, a torque sensor may be installed on the steering wheel column of the target vehicle, and the current steering wheel torque may be acquired by the torque sensor.

[0105] Since the target steering wheel angle is the steering wheel angle at the moment before the electric power steering system fails, that is, the steering wheel angle before the electric power steering system fails, the current steering wheel angle is the steering wheel angle after the electric power steering system fails. In this case, the target steering wheel angle and the current steering wheel angle can be used to know how much the steering wheel returns to the correct position after the electric power steering system fails, so that auxiliary steering can be performed later.

[0106] Optionally, an EPS status signal may be provided in the target vehicle.

[0107] The EPS status signal is used to indicate the operating status of the electric power steering system. For example, if the EPS status signal is 1, it means that the electric power steering system is not faulty and is operating normally. For another example, if the EPS status signal is 0, it means that the electric power steering system is faulty.

[0108] In this case, the EPS status signal can be used to determine whether the electric power steering system is faulty.

[0109] Optionally, in an embodiment of the present application, when an electric power steering system fails, it is also possible to first determine whether the target vehicle is in a steering state; when the target vehicle is in a steering state, the current vehicle speed, target steering wheel angle, current steering wheel angle and current steering wheel torque of the target vehicle are obtained.

[0110] Among them, the operation of judging whether the target vehicle is in a turning state can be: when the current vehicle speed of the target vehicle is less than a preset vehicle speed threshold and the current steering wheel angle is greater than a preset steering wheel angle threshold, it is determined that the target vehicle is in a turning state; when the current vehicle speed is greater than or equal to the preset vehicle speed threshold and / or the current steering wheel angle is less than or equal to the preset steering wheel angle threshold, it is determined that the target vehicle is not in a turning state.

[0111] The preset vehicle speed threshold and the preset steering wheel angle threshold can be set in advance, and the preset vehicle speed threshold can be set smaller, and the preset steering wheel angle threshold can be set larger.

[0112] Generally, when a vehicle is turning (such as a right-angle turn or a U-turn), it will be at a lower speed, because turning at a high speed will cause the vehicle to deviate from the expected trajectory, so the entire turning process will become difficult. Therefore, in the embodiment of the present application, it can also be determined whether the current vehicle speed meets the conditions.

[0113] In this case, when the current vehicle speed is less than the preset vehicle speed threshold and the current steering wheel angle is greater than the preset steering wheel angle threshold, it means that the current vehicle speed is low and the current steering wheel angle is large. That is to say, the target vehicle is currently driving at a low speed, but the driver turns the steering wheel at a large angle, so it can be determined that the target vehicle is currently turning, that is, the target vehicle is in a turning state.

[0114] When the current vehicle speed is greater than or equal to the preset vehicle speed threshold and / or the current steering wheel angle is less than or equal to the preset steering wheel angle threshold, it means that the current vehicle speed is high and the current steering wheel angle is low. That is to say, the target vehicle is currently traveling at a high speed, but the driver does not turn the steering wheel or turns the steering wheel slightly, then it can be determined that the target vehicle is currently traveling straight, that is, the target vehicle is not in a turning state.

[0115] Optionally, the preset steering wheel angle threshold value can also be set according to the angle of the steering wheel rotation during large-angle steering. In this case, the target vehicle can provide auxiliary steering to the driver when performing large-angle steering.

[0116] It is worth noting that when the vehicle is turning at a large angle, the steering wheel angle is generally above 90° (degrees). It may be difficult to operate within this steering range, so steering assistance is more needed. In this case, by setting a preset steering wheel angle threshold, the driver's assistance needs can be better met.

[0117] In the above case, after obtaining the current vehicle speed, the current steering wheel angle, the target steering wheel angle and the current steering wheel torque of the target vehicle, corresponding steering control can be performed accordingly, that is, continue to execute the following step 302.

[0118] Step 302: Based on the current steering wheel torque, determine the rear wheel angle gain and based on the current speed of the target vehicle, the target steering wheel angle and the current steering wheel angle, determine the initial steering angle difference. The rear wheel angle gain is used to indicate the urgency of the driver when steering, and the initial steering angle difference is the theoretical angle that the rear wheels of the target vehicle need to turn at the current speed.

[0119] Since the current steering wheel torque refers to the torque applied by the driver to the steering wheel, in general, the greater the curvature that the target vehicle needs to turn, the greater the torque that the driver needs to apply to the steering wheel to achieve a quick turn. Therefore, based on the current steering wheel torque, the urgency of the driver's steering can be determined, and based on this, it can be known whether the rear wheel steering angle should be adjusted larger or smaller in the future.

[0120] In addition, since the target steering wheel angle is the steering wheel angle at the moment before the electric power steering system fails, the current steering wheel angle is the steering wheel angle after the electric power steering system fails. Therefore, according to the target steering wheel angle and the current steering wheel angle, it can be known how much the steering wheel returns to the correct position after the electric power steering system fails. Based on this, the angle required for the rear wheels to rotate can be preliminarily calculated, that is, the initial angle difference can be determined.

[0121] In this case, by calculating the rear wheel steering gain and the initial steering angle difference, the urgency of the driver's steering and the theoretical angle of the target vehicle's rear wheels at the current speed can be known. The target vehicle can then be accurately controlled based on the rear wheel steering gain and the initial steering angle difference to meet the driver's steering needs.

[0122] Optionally, the operation of determining the rear wheel steering angle gain based on the current steering wheel torque may be: based on the current steering wheel torque, acquiring the corresponding rear wheel steering angle gain from a preset corresponding relationship.

[0123] The preset correspondence refers to the correspondence between the steering wheel torque and the rear wheel steering angle gain, and the preset correspondence includes multiple steering wheel torques and multiple rear wheel steering angle gains, wherein each of the multiple rear wheel steering angle gains corresponds to a corresponding steering wheel torque.

[0124] Optionally, the preset corresponding relationship can be experimentally calibrated in advance by a technician. For example, the technician can apply different steering wheel torques to a vehicle with the power-assist function turned on, observe the change in the steering angle of the rear wheels, and then quantify the change in the steering angle of the rear wheels under different steering wheel torques to obtain the rear wheel steering angle gain under different steering wheel torques.

[0125] For example, Table 1 is an example of a preset corresponding relationship. Referring to Table 1, Table 1 includes multiple steering wheel torques and multiple rear wheel steering angle gains, wherein each rear wheel steering angle gain corresponds to a corresponding steering wheel torque. For example, the current steering wheel torque is 10, and the rear wheel steering angle gain corresponding to the current steering wheel torque obtained from Table 1 is 1.6.

[0126] Table 1

[0127]

[0128] The embodiment of the present application only uses the above Table 1 as an example to illustrate the preset corresponding relationship, and does not constitute a limitation on the embodiment of the present application.

[0129] Optionally, based on the current vehicle speed of the target vehicle, the target steering wheel angle, and the current steering wheel angle, the operation of determining the initial steering angle difference may be implemented in the following three possible ways.

[0130] A first possible implementation method is to subtract the target steering wheel angle from the current steering wheel angle to obtain a steering wheel angle difference; based on the steering wheel angle difference and the current vehicle speed, a corresponding initial angle difference is obtained from the target correspondence.

[0131] The steering wheel angle difference refers to the angle at which the steering wheel returns to normal after a failure of the electric power steering system.

[0132] The target correspondence refers to the correspondence between the steering wheel angle difference, the vehicle speed and the initial angle difference. The target correspondence includes multiple steering wheel angle differences, multiple vehicle speeds and multiple initial angle differences, wherein a steering wheel angle difference and a vehicle speed combination correspond to a corresponding initial angle difference.

[0133] Specifically, the target correspondence relationship can be experimentally calibrated by a technician. For example, the technician can control the vehicle to be at different speeds, and control the electric power steering system to be turned off during the steering process, and turn the steering wheel during the steering process to obtain different steering wheel angle differences. Then, for the steering wheel angle difference at a certain speed, the rear wheels are controlled to rotate at different angles to observe which angle can make the vehicle turn smoothly. The angle of rotation of the rear wheels is then determined as the initial angle difference corresponding to this speed and this steering wheel angle difference. By conducting the above experiments for different speeds and different steering wheel angle differences, the initial angle differences corresponding to different speeds and different steering wheel angle differences can be obtained, and thus the target correspondence relationship can be obtained.

[0134] For example, Table 2 is an example of a target correspondence relationship. Referring to Table 2, Table 2 includes multiple steering wheel angle differences, multiple vehicle speeds, and multiple initial angle differences. One steering wheel angle difference and one vehicle speed correspond to a corresponding initial angle difference. For example, if the steering wheel angle difference is 15 and the current vehicle speed is 12, then it can be determined that the initial angle difference is 3.5.

[0135] Table 2

[0136]

[0137] The embodiment of the present application only uses the above Table 2 as an example to illustrate the target correspondence relationship, and does not constitute a limitation to the embodiment of the present application.

[0138] In this way, based on the steering wheel return angle and the current vehicle speed after the electric power steering system fails, a more accurate initial turning angle difference can be determined. In addition, the target corresponding relationship is obtained by pre-calibration by the technician, so that the initial turning angle difference can be determined more quickly in the future, thereby improving the efficiency of determining the initial turning angle difference.

[0139] In an embodiment of the present application, when the steering wheel angle difference is greater than the target angle difference, the target angle difference and the initial angle difference corresponding to the current vehicle speed are obtained from the target correspondence relationship; the target angle difference and the initial angle difference corresponding to the current vehicle speed are determined as the final initial angle difference.

[0140] In this case, an adjustment limit value is set for the rear wheel angle. When the steering wheel angle difference is large, the target angle difference and the initial angle difference corresponding to the current vehicle speed are used as the limit. Subsequently, the rear wheel angle is always adjusted based on the target angle difference and the initial angle difference corresponding to the current vehicle speed.

[0141] A second possible implementation method is to subtract the target steering wheel angle from the current steering wheel angle to obtain a steering wheel angle difference; divide the steering wheel angle difference by the gear ratio of the target vehicle to obtain a front wheel angle difference; and multiply the front wheel angle difference by a control coefficient to obtain an initial angle difference.

[0142] The gear ratio is used to represent the relationship between the steering wheel angle and the front wheel angle. Optionally, the gear ratio of the target vehicle is generally stored in the vehicle's memory, and is subsequently directly obtained from the memory when the gear ratio of the target vehicle is needed.

[0143] The control coefficient is used to indicate the ratio between the front wheel steering angle and the rear wheel steering angle. Generally, when the vehicle is driving at a low speed, the control coefficient is usually a negative value, indicating that the rear wheels are turning in the opposite direction to the front wheels. When the vehicle is driving at a high speed, the control coefficient is usually a positive value, indicating that the rear wheels are turning in the same direction as the front wheels.

[0144] In this case, it is equivalent to first determining the difference in the front wheel steering angle before and after the electric power steering system failure based on the steering wheel angle difference, and then multiplying the front wheel angle by the control coefficient, which is equivalent to directly assigning the corresponding steering angle to the rear wheels to assist the front wheels in better steering. In this way, the process of determining the initial steering angle difference is more convenient.

[0145] A third possible implementation method is to first obtain the target vehicle speed and target heading angle, the wheelbase and gear ratio of the target vehicle, and the current heading angle at a previous moment when the electric power steering system of the target vehicle fails; and determine the initial steering angle difference based on the target vehicle's current speed, target speed, wheelbase, gear ratio, current heading angle, target heading angle, target steering wheel angle, and current steering wheel angle.

[0146] The operation of determining the initial steering angle difference based on the current vehicle speed, target vehicle speed, wheelbase, gear ratio, current heading angle, target heading angle, target steering wheel angle and current steering wheel angle of the target vehicle may include the following steps (1) to (3).

[0147] (1) Based on the wheelbase and gear ratio, target heading angle, target vehicle speed, and target steering wheel angle of the target vehicle, the first driving trajectory of the target vehicle before the electric power steering system fails is predicted.

[0148] Since the purpose of the steering assistance in the embodiment of the present application is to maintain the original driving trajectory by assisting the steering with the rear wheels when the electric power steering system fails, the driving trajectory before the electric power steering system fails can be predicted first.

[0149] Specifically, the operation of step (1) may be: dividing the target steering wheel angle by the gear ratio of the target vehicle to obtain a target front wheel angle; determining a target angular velocity of the target vehicle based on the target front wheel angle, the target vehicle speed, and the wheelbase; updating the position of the target vehicle at multiple times based on the target angular velocity and the target heading angle with the current position of the target vehicle as the initial position; and fitting the position of the target vehicle at multiple times to obtain a first driving trajectory.

[0150] The target front wheel turning angle is the front wheel turning angle of the target vehicle at a moment before the electric power steering system fails.

[0151] The target angular velocity refers to the angular velocity of the target vehicle at a moment before the electric power steering system fails.

[0152] In this case, the front wheel turning angle at the moment before the electric power steering system fails is calculated, and then the angular velocity of the target vehicle is calculated. Subsequently, based on the angular velocity and the target heading angle, the possible driving position and heading angle of the vehicle are predicted step by step. In this way, the first driving trajectory of the target vehicle can be accurately predicted.

[0153] The operation of determining the target angular velocity of the target vehicle based on the target front wheel steering angle, the target vehicle speed and the wheelbase may be as follows: based on the target front wheel steering angle, the target vehicle speed and the wheelbase, the target angular velocity of the target vehicle is determined by the following formula (1).

[0154] (1)

[0155] in, is the target angular velocity of the target vehicle, is the target speed of the target vehicle, L is the wheelbase of the target vehicle, is the target front wheel turning angle.

[0156] Among them, the operation of updating the position of the target vehicle at multiple moments based on the target angular velocity and the target heading angle with the current position of the target vehicle as the initial position can be: for the position at the first moment among the multiple moments, determine the heading angle at the first moment based on the time step, the target angular velocity and the target heading angle; determine the position of the target vehicle at the first moment based on the target vehicle speed, the time step, the heading angle at the first moment and the initial position of the target vehicle; for the position at the i-th moment among the multiple moments, determine the heading angle at the i-th moment based on the time step, the target angular velocity and the heading angle at the i-1-th moment; determine the position of the target vehicle at the i-th moment based on the target vehicle speed, the time step, the heading angle at the i-th moment and the position of the target vehicle at the i-1-th moment, wherein i is an integer greater than or equal to 2.

[0157] The time step refers to the time interval between two adjacent moments. The time step can be set by the technician. For example, the time step is set to 0.1s (seconds).

[0158] The operation of determining the heading angle at the i-th moment based on the time step, the target angular velocity and the heading angle at the i-1th moment may be: based on the time step, the target angular velocity and the heading angle at the i-1th moment, the heading angle at the i-th moment is determined by the following formula (2).

[0159] (2)

[0160] in, is the heading angle at the i-th moment, is the heading angle at the i-1th moment, is the duration step length.

[0161] Wherein, based on the target vehicle speed, time step, heading angle at the i-th moment and the position of the target vehicle at the i-1th moment, the operation of determining the position of the target vehicle at the i-th moment may be: based on the target vehicle speed, time step, heading angle at the i-th moment and the position of the target vehicle at the i-1th moment, the position of the target vehicle at the i-th moment is determined by the following formula (3) and formula (4).

[0162] (3)

[0163] (4)

[0164] in, is the position of the target vehicle at the i-th moment, is the position of the target vehicle at the i-1th moment. In the embodiment of the present application, the current position of the target vehicle is (0, 0).

[0165] From the above process, it can be seen that the process of determining the first driving trajectory is: first calculate the angular velocity of the target vehicle, then update the heading angle of the target vehicle at the next moment according to the angular velocity and the target heading angle of the target vehicle, then determine the distance the target vehicle has advanced in the heading angle direction, and finally update the position of the target vehicle at the next moment based on the position of the target vehicle at the previous moment. In this way, by repeatedly using the above formula (2) to formula (4), the position of the target vehicle at multiple moments can be updated, thereby obtaining the first driving trajectory of the target vehicle.

[0166] The following example illustrates the process of determining the first driving trajectory of the target vehicle. For example, the current position of the target vehicle is (0, 0), the target heading angle is 0, the target front wheel angle The angle is 30°, the wheelbase L is 2.8 meters, the target vehicle speed is 10 meters per second, and the time step is 0.1 seconds.

[0167] Calculation of the position of the target vehicle at the first moment among multiple moments:

[0168] (a) Calculate the angular velocity of the target vehicle

[0169]

[0170] (b) Calculate the heading angle at the first moment

[0171]

[0172] (c) Calculate the position of the target vehicle at the first moment

[0173]

[0174]

[0175] By continuously iterating the above formula (2) to formula (4), the position of the target vehicle at multiple times can be obtained, that is, the first driving trajectory of the target vehicle can be obtained.

[0176] It should be noted that, in the embodiment of the present application, by performing multiple calculations based on multiple parameters, the heading angle and position of the target vehicle at multiple times can be accurately predicted, thereby improving the prediction accuracy of the first driving trajectory of the target vehicle.

[0177] (2) Based on the wheelbase and gear ratio of the target vehicle, the current heading angle, the current vehicle speed, and the current steering wheel angle, predict the second driving trajectory of the target vehicle after the electric power steering system fails.

[0178] The purpose of the steering assistance in the embodiment of the present application is: when the electric power steering system fails, the steering assistance through the rear wheels can maintain the original driving trajectory. However, when the electric power steering system fails, the steering wheel angle will return to the normal position, and the driving trajectory of the target vehicle will change. Therefore, the driving trajectory of the target vehicle after the electric power steering system fails can also be predicted.

[0179] Specifically, the operation of step (2) may be: dividing the current steering wheel angle by the gear ratio of the target vehicle to obtain the current front wheel angle; determining the current angular velocity of the target vehicle based on the current front wheel angle, the current vehicle speed and the wheelbase; updating the position of the target vehicle at multiple times based on the current angular velocity and the current heading angle with the current position of the target vehicle as the initial position, fitting the position of the target vehicle at multiple times to obtain the second driving trajectory.

[0180] The operation of determining the current angular velocity of the target vehicle based on the current front wheel steering angle, the current vehicle speed and the wheelbase may be as follows: based on the current front wheel steering angle, the current vehicle speed and the wheelbase, the current angular velocity of the target vehicle is determined by the following formula (5).

[0181] (5)

[0182] in, is the current angular velocity of the target vehicle, is the current speed of the target vehicle, is the current front wheel steering angle.

[0183] Among them, the operation of updating the position of the target vehicle at multiple moments based on the current angular velocity and the current heading angle with the current position of the target vehicle as the initial position can be: for the position at the first moment among the multiple moments, determine the heading angle at the first moment based on the time step, the current angular velocity and the current heading angle; determine the position of the target vehicle at the first moment based on the current vehicle speed, the time step, the heading angle at the first moment and the initial position of the target vehicle; for the position at the i-th moment among the multiple moments, determine the heading angle at the i-th moment based on the time step, the current angular velocity and the heading angle at the i-1-th moment; determine the position of the target vehicle at the i-th moment based on the target vehicle speed, the time step, the heading angle at the i-th moment and the position of the target vehicle at the i-1-th moment.

[0184] The operation of determining the heading angle at the i-th moment based on the time step, the current angular velocity and the heading angle at the i-1th moment may be as follows: based on the time step, the current angular velocity and the heading angle at the i-1th moment, the heading angle at the i-th moment is determined by the following formula (6).

[0185] (6)

[0186] Wherein, based on the target vehicle speed, time step, heading angle at the i-th moment and the position of the target vehicle at the i-1th moment, the operation of determining the position of the target vehicle at the i-th moment may be: based on the target vehicle speed, time step, heading angle at the i-th moment and the position of the target vehicle at the i-1th moment, the position of the target vehicle at the i-th moment is determined by the following formulas (7) and (8).

[0187] (7)

[0188] (8)

[0189] From the above process, it can be seen that the process of determining the second driving trajectory is: first calculate the current angular velocity of the target vehicle, then update the heading angle of the target vehicle at the next moment according to the current angular velocity and current heading angle of the target vehicle, then determine the distance the target vehicle has advanced in the heading angle direction, and finally update the position of the target vehicle at the next moment based on the position of the target vehicle at the previous moment. In this way, by repeatedly using the above formulas (6) to (8), the position and heading angle of the target vehicle at multiple moments can be updated, thereby obtaining the second driving trajectory of the target vehicle.

[0190] Since the specific operation of predicting the second driving trajectory of the target vehicle after the electric power steering system fails based on the target vehicle's wheelbase and gear ratio, current heading angle, current vehicle speed and current steering wheel angle is similar to the above-mentioned operation of predicting the first driving trajectory of the target vehicle before the electric power steering system fails based on the target vehicle's wheelbase and gear ratio, target heading angle, target vehicle speed and target steering wheel angle, the embodiment of the present application will not be elaborated on this.

[0191] (3) Determine an initial turning angle difference based on the first driving trajectory, the second driving trajectory, and the wheelbase of the target vehicle.

[0192] Since the purpose of the steering assistance in the embodiment of the present application is to maintain the original driving trajectory by providing steering assistance through the rear wheels when the electric power steering system fails, the initial angle difference can be determined based on the first driving trajectory and the second driving trajectory, the current steering wheel angle and the wheelbase.

[0193] The operation of step (3) may be: determining a first turning radius of the target vehicle based on the first driving trajectory, and determining a second turning radius of the target vehicle based on the second driving trajectory; determining a target radius difference based on the first turning radius and the second turning radius; and determining an initial turning angle difference based on the target radius difference and the wheelbase.

[0194] The target radius difference can reflect the difference between the turning radius of the target vehicle before the electric power steering system fails and the turning radius of the target vehicle after the electric power steering system fails, so that the angle by which the rear wheels should turn can be accurately calculated.

[0195] In this case, the first driving trajectory is used as a standard to determine the difference between the current driving trajectory of the vehicle and the previous driving trajectory, so that the vehicle's driving trajectory is made close to the first driving trajectory by controlling the rear wheels. In this way, a relatively accurate initial turning angle difference can be determined.

[0196] The operation of determining the first turning radius of the target vehicle based on the first driving trajectory may be: determining the first turning radius of the target vehicle based on the first driving trajectory by using the following formula (9).

[0197] (9)

[0198] in, is the first turning radius, is the center coordinate of the first driving trajectory, is an arbitrary trajectory point on the first driving trajectory.

[0199] In addition, the operation of determining the second turning radius of the target vehicle based on the second driving trajectory is similar to the operation of determining the first turning radius of the target vehicle based on the first driving trajectory, and will not be repeated here.

[0200] Since the target vehicle is actually making a circular motion when turning at a certain angle within a period of time, the target vehicle's driving trajectory may be an arc. In this case, the first turning radius can be determined more conveniently by the above formula (9).

[0201] The operation of determining the initial turning angle difference based on the target radius difference and the wheelbase may be: determining the initial turning angle difference based on the target radius difference and the wheelbase by using the following formula (10).

[0202] (10)

[0203] in, is the initial angle difference, k is the control coefficient, is the target radius difference.

[0204] In this way, by combining the first driving trajectory and the second driving trajectory in the above step (3), an accurate initial turning angle difference can be determined. The rear wheel turning angle can be adjusted using this initial turning angle difference, so that the vehicle can maintain the original driving trajectory, thereby avoiding the driver's nervousness.

[0205] Step 303: Based on the rear wheel steering angle gain of the target vehicle and the initial steering angle difference, the target vehicle is controlled to adjust the rear wheel steering angle.

[0206] In this case, a rear wheel steering angle that can meet the driver's steering needs can be determined based on the rear wheel steering gain and the initial steering angle difference, and the turning radius of the target vehicle can be reduced by adjusting the rear wheel steering angle. This can provide steering assistance to the driver, allowing the vehicle to maintain its original driving trajectory, thereby avoiding the driver's nervousness and facilitating driving safety.

[0207] Optionally, the operation of step 303 may be: multiplying the rear wheel steering angle gain by the initial steering angle difference to obtain a target rear wheel steering angle; and controlling the rear wheels of the target vehicle to rotate to the target rear wheel steering angle.

[0208] Since the rear wheel steering angle gain is used to indicate the urgency of the driver's steering, the more urgent the driver is in steering, the greater the rear wheel steering angle gain is, and the greater the steering angle of the rear wheels is.

[0209] In this case, a more accurate rear wheel steering angle (that is, a target rear wheel steering angle) can be obtained by multiplying the rear wheel steering gain by the initial steering angle difference, so that the rear wheels of the target vehicle can be accurately controlled to provide a rear wheel steering angle that can meet the driver's needs, thereby improving the accuracy of determining the rear wheel steering angle.

[0210] After controlling the target vehicle to adjust the rear wheel steering angle, the following steps (1) to (4) may also be included.

[0211] (1) Determine the driver’s driving intention based on the road information of the target vehicle and the current steering wheel angle.

[0212] The road information may be an image of the road that the target vehicle is located in. In the embodiment of the present application, a camera may be installed on the target vehicle, and the image of the road that the target vehicle is located in may be collected by the camera.

[0213] The driver's driving intention may include turning or going straight.

[0214] In this case, the current steering wheel angle can reflect whether the driver has turned the steering wheel, and the road information of the target vehicle can reflect the lane lines, intersection information, etc. of the target vehicle's road. Then, the road information and the current steering wheel angle can be combined to determine whether the driver currently wants to turn.

[0215] Optionally, based on the road information of the road where the target vehicle is located and the current steering wheel angle, the operation of determining the driver's driving intention can be: performing road recognition on the road information of the road where the target vehicle is located; when the recognition result is any one of an intersection, a T-junction, and a curve, judging whether the current steering wheel angle is greater than a preset angle threshold; when the current steering wheel angle is greater than the preset angle threshold, determining that the driver's driving intention is turning; when the recognition results are neither an intersection, a T-junction, a curve and / or the current steering wheel angle is less than or equal to the preset angle threshold, determining that the driver's driving intention is going straight.

[0216] In this case, when the recognition result is any one of a crossroad, a T-junction, or a curve, it means that the target vehicle may be at a crossroad, a T-junction, or a curve, and the driver may turn at this time. The current steering wheel angle is then determined. If the current steering wheel angle is greater than the preset angle threshold, it means that the driver has turned the steering wheel at this time, and the steering wheel turning angle is large, so the driver is likely to turn. In this case, it can be determined that the driver's driving intention is to turn.

[0217] When the recognition results are not a crossroad, a T-junction, or a curve, it means that the target vehicle is not at a crossroad, a T-junction, or a curve, and the target vehicle is likely to be on a straight road. When the current steering wheel angle is less than or equal to the preset angle threshold, it means that the driver has not turned the steering wheel or has turned the steering wheel slightly, and in this case the driver is likely not to turn, and it can be determined that the driver's driving intention is to go straight.

[0218] (2) When the driver's driving intention is to turn, a recommended driving trajectory of the target vehicle is determined based on the road information.

[0219] The recommended driving trajectory is a driving trajectory that enables the target vehicle to turn smoothly.

[0220] In this case, when the driver wants to turn, he can determine a driving trajectory that can enable the target vehicle to turn smoothly based on the road information, so that subsequent drivers can refer to this recommended driving trajectory to turn the vehicle, allowing the driver to turn the vehicle more conveniently.

[0221] The operation of step (2) may be: performing lane line recognition and obstacle recognition on the road information to determine the lane lines around the target vehicle and the positions of obstacles; performing path planning based on the current position of the target vehicle, the lane lines around the target vehicle, the positions of obstacles and the end position to obtain a recommended driving trajectory for the target vehicle.

[0222] The current position of the target vehicle refers to the position of the target vehicle relative to the lane line, that is, the position of the target vehicle in the lane line. The end position can be a position in the lane line on the road after the target vehicle turns, or it can also be a position on the road where the target vehicle turns.

[0223] In this case, it is equivalent to first determining the position of the lane lines and obstacles, and then performing path planning based on the starting and ending positions of the target vehicle, as well as the positions of the lane lines and obstacles, so as to plan a route that the target vehicle can travel, and the target vehicle can turn smoothly based on this route. In this way, path planning based on the positions of lane lines and obstacles can obtain an accurate recommended driving trajectory.

[0224] In the embodiment of the present application, it can also be determined whether the target vehicle is in the first lane on the left or the first lane on the right. Subsequently, when the target vehicle is in the first lane on the left, based on the current position of the target vehicle, the lane lines around the target vehicle, the position of obstacles and the terminal position, a path planning is performed to the left to obtain a recommended driving trajectory of the target vehicle; when the target vehicle is in the first lane on the right, based on the current position of the target vehicle, the lane lines around the target vehicle, the position of obstacles and the terminal position, a path planning is performed to the right to obtain a recommended driving trajectory of the target vehicle.

[0225] (3) Predict a third driving trajectory based on the current steering wheel angle, the adjusted rear wheel angle, the wheelbase of the target vehicle, and the current speed.

[0226] The third driving track is the driving track of the target vehicle after the rear wheel angle is adjusted, that is, the driving track of the target vehicle currently traveling. In this case, after adjusting the rear wheel turning angle of the target vehicle, the driving track of the target vehicle can be continuously predicted.

[0227] The operation of step (3) may be as follows: inputting the current steering wheel angle, the adjusted rear wheel angle, the wheelbase and the current vehicle speed of the target vehicle into a trajectory prediction model, processing the current steering wheel angle, the adjusted rear wheel angle, the wheelbase and the current vehicle speed of the target vehicle through the trajectory prediction model, and outputting a third driving trajectory.

[0228] The trajectory prediction model is used to predict the driving trajectory of the target vehicle. The trajectory prediction model can be a convolutional neural network model, a recurrent neural network model, etc., which is not limited in the embodiment of the present application.

[0229] In this way, by predicting the third driving trajectory through the neural network model, the third driving trajectory can be predicted more conveniently and the prediction efficiency of the third driving trajectory can be improved.

[0230] (4) Control the target vehicle to project the proposed driving trajectory and the third driving trajectory.

[0231] Since the suggested driving trajectory is the driving trajectory that the target vehicle can pass smoothly when turning, the third driving trajectory is the possible driving trajectory of the target vehicle after adjusting the rear wheel turning angle of the rear wheel. In this case, by projecting the suggested driving trajectory and the third driving trajectory, the driver can see the driving trajectory that the target vehicle can pass smoothly and the current driving trajectory of the target vehicle itself. Then when the current driving trajectory of the target vehicle itself deviates greatly from the suggested driving trajectory, the driver can adjust the steering wheel based on the suggested driving trajectory to minimize the deviation between the driving trajectory of the target vehicle itself and the suggested driving trajectory, so that the target vehicle can turn smoothly. In this way, the user's driving experience is improved, and by providing a reference for the driver, the driver's nervousness can also be eliminated, making the entire steering process more convenient.

[0232] For example, Figure 4 is a projection diagram of the recommended driving trajectory and the third driving trajectory, see Figure 4 , Figure 4 The target vehicle 401, the suggested driving track 402 and the third driving track 403 are included. The target vehicle 401 projects the suggested driving track 402 and the third driving track 403 forward.

[0233] In the embodiment of the present application, a projection lamp may be installed on the target vehicle, and the projection lamp may be installed on the front of the vehicle. Optionally, the operation of step (4) may be: projecting the suggested driving trajectory and the third driving trajectory by the projection lamp of the target vehicle.

[0234] It is worth noting that through the above steps 301 to 303, when the electric power steering system of the target vehicle fails, the rear wheel steering angle of the target vehicle can be adjusted, so that the driver can be assisted in steering by adjusting the rear wheel steering angle.

[0235] In the embodiment of the present application, the EPS status signal can be further monitored, and when the EPS status signal returns to 1, the electric power steering system can provide assistance to the target vehicle. That is, when the EPS function is restored, that is, when there is no fault, the electric power steering system can continue to provide assistance.

[0236] In this case, the target vehicle can be controlled to adjust the rear wheel angle based on the current steering wheel angle. Specifically, the target angle can be determined based on the current steering wheel angle, and the target angle and target steering speed can be sent to the rear wheel steering system, so that the rear wheel steering system controls the rear wheels to turn to the target angle at the target steering speed.

[0237] The target steering speed can be set in advance, for example, the target steering speed is 5° / s (degrees / second). In this case, when the EPS function is restored, the rear wheel steering angle is adjusted to the rear wheel steering angle corresponding to the current steering wheel angle, so that the rear wheel steering angle is used for normal driving of the target vehicle.

[0238] It is worth noting that the steering control method provided in the embodiment of the present application enables the target vehicle to maintain its original driving track by appropriately adjusting the rear wheel steering angle, that is, increasing the rear wheel steering angle to reduce the turning radius when the electric power steering system of the target vehicle fails. In this way, the driver's nervousness can be avoided during steering, ensuring the driver's safe driving.

[0239] For ease of understanding, now combined Figure 5 The steering control method provided in the embodiment of the present application is exemplarily described, for example, Figure 5 is a flow chart of another steering control method provided in an embodiment of the present application, see Figure 5 , the steering control method includes the following steps.

[0240] Step 501: When EPS fails, obtain the steering wheel angle and vehicle speed of the target vehicle.

[0241] Step 502: Determine whether the steering wheel angle is greater than a preset steering wheel angle threshold and whether the vehicle speed is less than a preset vehicle speed threshold.

[0242] Step 503: When the steering wheel angle is greater than a preset steering wheel angle threshold and the vehicle speed is less than a preset vehicle speed threshold, the current vehicle speed, the current steering wheel angle, the target steering wheel angle and the current steering wheel torque are obtained. When the steering wheel angle is less than or equal to the preset steering wheel angle threshold and / or the vehicle speed is greater than or equal to the preset vehicle speed threshold, the rear wheel angle is controlled to remain unchanged or the rear wheel angle corresponding to the current steering wheel angle is sent.

[0243] Step 504: Subtract the target steering wheel angle from the current steering wheel angle to obtain a steering wheel angle difference.

[0244] Step 505: Determine the rear wheel steering angle gain based on the current steering wheel torque and determine the initial steering angle difference from the target correspondence based on the steering wheel steering angle difference and the current vehicle speed.

[0245] Step 506: Multiply the rear wheel steering angle gain by the initial steering angle difference to obtain a target rear wheel steering angle.

[0246] Step 507: Control the rear wheels of the target vehicle to rotate to a target rear wheel turning angle.

[0247] In an embodiment of the present application, when the electric power steering system of the target vehicle fails, the VCU first obtains the current speed, target steering wheel angle, current steering wheel angle and current steering wheel torque of the target vehicle, and then determines the rear wheel angle gain based on the current steering wheel torque, and determines the initial angle difference based on the current vehicle speed, the target steering wheel angle at the moment before the electric power steering system fails, and the current steering wheel angle when the electric system fails, that is, first determine the urgency of the driver's steering and the theoretical angle that the rear wheels of a target vehicle need to turn at the current speed. Then, based on the rear wheel angle gain of the target vehicle and the initial angle difference, the target vehicle is controlled to adjust the rear wheel angle. The rear wheel angle gain can know the urgency of the driver's steering, and thus it can be known whether the rear wheel angle should be larger or smaller. In this way, a rear wheel steering angle that can meet the driver's steering needs can be determined based on the rear wheel steering gain and the initial steering angle difference. The driver's steering is then assisted by adjusting the rear wheel steering angle, so that the vehicle can maintain its original driving trajectory, thereby avoiding the driver's nervousness and facilitating driving safety.

[0248] Figure 6 is a schematic diagram of the structure of a steering control device provided in an embodiment of the present application. The steering control device can be implemented by software, hardware or a combination of both to form part or all of a vehicle, and the vehicle can be as follows Figure 7 Vehicle shown. Figure 6 The device includes: a first acquisition module 601, a first determination module 602 and a control module 603.

[0249] The first acquisition module 601 is used to acquire the current vehicle speed, target steering wheel angle, current steering wheel angle and current steering wheel torque of the target vehicle when the electric power steering system of the target vehicle fails, wherein the target steering wheel angle is the steering wheel angle at a moment before the electric power steering system of the target vehicle fails;

[0250] A first determination module 602 is used to determine a rear wheel steering angle gain based on the current steering wheel torque and an initial steering angle difference based on the current vehicle speed, the target steering wheel angle and the current steering wheel angle of the target vehicle, wherein the rear wheel steering angle gain is used to indicate the urgency of the driver when steering, and the initial steering angle difference is a theoretical angle required for the rear wheels of the target vehicle to rotate at the current vehicle speed;

[0251] The control module 603 is used to control the target vehicle to adjust the rear wheel steering angle based on the rear wheel steering angle gain and the initial steering angle difference of the target vehicle.

[0252] Optionally, the control module 603 is used to:

[0253] Multiply the rear wheel steering angle gain by the initial steering angle difference to obtain the target rear wheel steering angle;

[0254] The rear wheels of the target vehicle are controlled to rotate to a target rear wheel turning angle.

[0255] Optionally, the first determining module 602 is used to:

[0256] Subtract the target steering wheel angle from the current steering wheel angle to obtain the steering wheel angle difference;

[0257] Based on the steering wheel angle difference and the current vehicle speed, a corresponding initial angle difference is obtained from the target correspondence.

[0258] Optionally, the device further comprises:

[0259] A first acquisition module is used to acquire the target vehicle speed and target heading angle at a previous moment when the electric power steering system of the target vehicle fails, the wheelbase and gear ratio of the target vehicle, and the current heading angle;

[0260] Optionally, the first determining module 602 is used to:

[0261] An initial steering angle difference is determined based on the current vehicle speed of the target vehicle, the target vehicle speed, the wheelbase, the gear ratio, the current heading angle, the target steering wheel angle, the target heading angle, and the current steering wheel angle.

[0262] Optionally, the first determining module 602 is used to:

[0263] Predicting a first driving trajectory of the target vehicle before a failure of the electric power steering system occurs based on the wheelbase of the target vehicle and the gear ratio, the target heading angle, the target vehicle speed, and the target steering wheel angle;

[0264] Based on the wheelbase of the target vehicle and the gear ratio, the current heading angle, the current vehicle speed, and the current steering wheel angle, predict a second driving trajectory of the target vehicle after the electric power steering system fails;

[0265] The initial turning angle difference is determined based on the first driving trajectory, the second driving trajectory and the wheelbase.

[0266] Optionally, the first determining module 602 is used to:

[0267] The target steering wheel angle is divided by the gear ratio to obtain a target front wheel angle, which is the front wheel angle of the target vehicle at a moment before the electric power steering system fails.

[0268] Determining a target angular velocity of the target vehicle based on the target front wheel steering angle, the target vehicle speed, and the wheelbase;

[0269] Based on the target angular velocity and the target heading angle, the position of the target vehicle at multiple times is updated with the current position of the target vehicle as the initial position;

[0270] The positions of the target vehicle at multiple times are fitted to obtain a first driving trajectory.

[0271] Optionally, the first determining module 602 is used to:

[0272] Determining a first turning radius of the target vehicle based on the first driving trajectory, and determining a second turning radius of the target vehicle based on the second driving trajectory;

[0273] Determining a target radius difference based on the first turning radius and the second turning radius;

[0274] Based on the target radius difference and the wheelbase, an initial turning angle difference is determined.

[0275] Optionally, the device further comprises:

[0276] A second determination module is used to determine the driver's driving intention based on the road information of the target vehicle and the current steering wheel angle;

[0277] A third determination module is used to determine a recommended driving trajectory of the target vehicle based on the road information when the driving intention is to turn, where the recommended driving trajectory is a driving trajectory that enables the target vehicle to turn smoothly;

[0278] A prediction module, configured to predict a third driving trajectory based on the current steering wheel angle, the adjusted rear wheel angle, the wheelbase and the current vehicle speed of the target vehicle, where the third driving trajectory is the driving trajectory of the target vehicle after the rear wheel angle is adjusted;

[0279] The projection module is used to control the target vehicle to project the suggested driving trajectory and the third driving trajectory.

[0280] In an embodiment of the present application, when the electric power steering system of the target vehicle fails, the current vehicle speed, target steering wheel angle, current steering wheel angle and current steering wheel torque of the target vehicle are first obtained, and then the rear wheel angle gain is determined based on the current steering wheel torque, and the initial angle difference is determined based on the current vehicle speed, the target steering wheel angle at the previous moment when the electric power steering system fails and the current steering wheel angle when the electric system fails, that is, the urgency of the driver's steering and the theoretical angle that the rear wheels of a target vehicle need to rotate at the current speed are first determined. Then, based on the rear wheel angle gain of the target vehicle and the initial angle difference, the target vehicle is controlled to adjust the rear wheel angle. The rear wheel angle gain can know the urgency of the driver's steering, and thus it can be known whether the rear wheel angle should be larger or smaller. In this way, a rear wheel steering angle that can meet the driver's steering needs can be determined based on the rear wheel steering gain and the initial steering angle difference. The driver's steering is then assisted by adjusting the rear wheel steering angle, so that the vehicle can maintain its original driving trajectory, thereby avoiding the driver's nervousness and facilitating driving safety.

[0281] It should be noted that: the steering control device provided in the above embodiment only uses the division of the above-mentioned functional modules as an example when performing steering control on a vehicle. In actual applications, the above-mentioned functions can be assigned to different functional modules as needed, that is, the internal structure of the device can be divided into different functional modules to complete all or part of the functions described above.

[0282] The functional units and modules in the above embodiments may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit, and the above integrated units may be implemented in the form of hardware or in the form of software functional units. In addition, the specific names of the functional units and modules are only for the convenience of distinguishing each other, and are not used to limit the protection scope of the embodiments of the present application.

[0283] The steering control device and the steering control method embodiments provided in the above embodiments belong to the same concept. The specific working process of the units and modules in the above embodiments and the technical effects brought about can be found in the method embodiment part and will not be repeated here.

[0284] Figure 7 It is a structural schematic diagram of a vehicle provided in an embodiment of the present application.

[0285] For example, Figure 7 As shown, the vehicle 700 includes: a memory 71 and a processor 70, wherein the memory 71 stores an executable program code 72, and the processor 70 is used to call and execute the executable program code 72 to perform the above-mentioned steering control method.

[0286] In this embodiment, the functional modules of the vehicle can be divided according to the above method example. For example, each functional module can be corresponded, or two or more functions can be integrated into one processing module. The above integrated module can be implemented in the form of hardware. It should be noted that the division of modules in this embodiment is schematic and is only a logical function division. There may be other division methods in actual implementation.

[0287] In the case of dividing each functional module according to each function, the vehicle may include: a first acquisition module, a first determination module and a control module. It should be noted that all relevant contents of each step involved in the above method embodiment can be referred to the functional description of the corresponding functional module, which will not be repeated here.

[0288] The vehicle provided in this embodiment is used to execute the above-mentioned steering control method, and thus can achieve the same effect as the above-mentioned implementation method.

[0289] In the case of an integrated unit, the vehicle may include a processing module and a storage module. The processing module may be used to control and manage the actions of the vehicle. The storage module may be used to support the vehicle in executing corresponding program codes and data.

[0290] The processing module may be a processor or a controller, which may implement or execute various exemplary logic blocks, modules and circuits shown in combination with the contents disclosed in this application. The processor may also be a combination that implements computing functions, such as a combination of one or more microprocessors, a combination of digital signal processing (DSP) and a microprocessor, etc. The storage module may be a memory.

[0291] This embodiment also provides a computer-readable storage medium, in which a computer program code is stored. When the computer program code is run on a computer, the computer executes the above-mentioned related method steps to implement the above-mentioned steering control method in the above-mentioned embodiment.

[0292] This embodiment also provides a computer program product. When the computer program product is run on a computer, the computer is enabled to execute the above-mentioned related steps to implement the above-mentioned steering control method in the above-mentioned embodiment.

[0293] Among them, the vehicle, computer-readable storage medium, computer program product or chip provided in this embodiment are all used to execute the method provided above. Therefore, the beneficial effects that can be achieved can refer to the beneficial effects in the method provided above and will not be repeated here.

[0294] Through the description of the above implementation methods, technical personnel in the relevant field can understand that for the convenience and brevity of description, only the division of the above-mentioned functional modules is used as an example. In actual applications, the above-mentioned functions can be assigned to different functional modules as needed, that is, the internal structure of the device can be divided into different functional modules to complete all or part of the functions described above.

[0295] In the embodiments provided in the present application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are schematic, for example, the division of modules or units is only a logical function division, and there may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another device, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0296] The above contents are only specific implementation methods of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A steering control method, characterized in that: The method comprises: In the case that the electric power steering system of the target vehicle fails, obtaining the current vehicle speed, target steering wheel angle, current steering wheel angle and current steering wheel torque of the target vehicle, wherein the target steering wheel angle is the steering wheel angle at a moment before the electric power steering system of the target vehicle fails; Based on the current steering wheel torque, obtaining a corresponding rear wheel steering angle gain from a preset corresponding relationship, wherein the rear wheel steering angle gain is used to indicate the urgency of the driver when steering; and subtracting the target steering wheel angle from the current steering wheel angle to obtain a steering wheel angle difference; based on the steering wheel angle difference and the current vehicle speed, obtaining a corresponding initial steering angle difference from a target corresponding relationship, wherein the initial steering angle difference is a theoretical angle required for the rear wheels of the target vehicle to rotate at the current vehicle speed; Multiplying the rear wheel steering angle gain by the initial steering angle difference to obtain a target rear wheel steering angle; The rear wheels of the target vehicle are controlled to rotate to the target rear wheel turning angle.

2. The method according to claim 1, characterized in that The method further comprises: Obtaining the target vehicle speed and target heading angle at a moment before the electric power steering system of the target vehicle fails, the wheelbase and gear ratio of the target vehicle, and the current heading angle; The step of determining the initial rotation angle difference also includes: An initial steering angle difference is determined based on the current vehicle speed of the target vehicle, the target vehicle speed, the wheelbase, the gear ratio, the current heading angle, the target steering wheel angle, the target heading angle, and the current steering wheel angle.

3. The method according to claim 2, characterized in that The determining of the initial steering angle difference based on the current vehicle speed of the target vehicle, the target vehicle speed, the wheelbase, the gear ratio, the current heading angle, the target steering wheel angle, the target heading angle and the current steering wheel angle comprises: Predicting a first driving trajectory of the target vehicle before an electric power steering system fails based on the wheelbase and the gear ratio of the target vehicle, the target heading angle, the target vehicle speed, and the target steering wheel angle; Predicting a second driving trajectory of the target vehicle after a failure of an electric power steering system occurs based on the wheelbase and the gear ratio of the target vehicle, the current heading angle, the current vehicle speed, and the current steering wheel angle; The initial turning angle difference is determined based on the first driving trajectory, the second driving trajectory, and the wheelbase.

4. The method according to claim 3, characterized in that The method of predicting a first driving trajectory of the target vehicle before an electric power steering system fails based on the wheelbase and the gear ratio of the target vehicle, the target heading angle, the target vehicle speed, and the target steering wheel angle comprises: Dividing the target steering wheel angle by the gear ratio to obtain a target front wheel angle, wherein the target front wheel angle is the front wheel angle of the target vehicle at a moment before the electric power steering system fails; Determining a target angular velocity of the target vehicle based on the target front wheel steering angle, the target vehicle speed, and the wheelbase; Based on the target angular velocity and the target heading angle, updating the position of the target vehicle at multiple times with the current position of the target vehicle as the initial position; The positions of the target vehicle at multiple times are fitted to obtain the first driving trajectory.

5. The method according to claim 3, characterized in that The determining the initial turning angle difference based on the first driving trajectory, the second driving trajectory and the wheelbase includes: Determining a first turning radius of the target vehicle based on the first driving trajectory, and determining a second turning radius of the target vehicle based on the second driving trajectory; determining a target radius difference based on the first turning radius and the second turning radius; An initial turning angle difference is determined based on the target radius difference and the wheelbase.

6. The method according to claim 1, characterized in that The method further comprises: Determining the driver's driving intention based on the road information of the target vehicle and the current steering wheel angle; In the case where the driving intention is to turn, determining a recommended driving trajectory of the target vehicle based on the road information, wherein the recommended driving trajectory is a driving trajectory that enables the target vehicle to turn smoothly; Based on the current steering wheel angle, the adjusted rear wheel angle, the wheelbase and the current vehicle speed of the target vehicle, predict a third driving trajectory, where the third driving trajectory is the driving trajectory of the target vehicle after the rear wheel angle is adjusted; The target vehicle is controlled to project the suggested driving trajectory and the third driving trajectory.

7. A steering control device, characterized in that: The device comprises: A first acquisition module is used to acquire the current vehicle speed, target steering wheel angle, current steering wheel angle and current steering wheel torque of the target vehicle when the electric power steering system of the target vehicle fails, wherein the target steering wheel angle is the steering wheel angle at a moment before the electric power steering system of the target vehicle fails; A first determination module is used to obtain a corresponding rear wheel steering angle gain from a preset correspondence relationship based on the current steering wheel torque and to obtain a steering wheel angle difference by subtracting the target steering wheel angle from the current steering wheel angle; and to obtain a corresponding initial steering angle difference from a target correspondence relationship based on the steering wheel angle difference and the current vehicle speed, wherein the rear wheel steering angle gain is used to indicate the urgency of the driver when steering, and the initial steering angle difference is a theoretical angle required for the rear wheels of the target vehicle to rotate at the current vehicle speed; The control module is used to multiply the rear wheel steering angle gain by the initial steering angle difference to obtain a target rear wheel steering angle; and control the rear wheels of the target vehicle to rotate to the target rear wheel steering angle.

8. A vehicle, characterized in that: The vehicle comprises: A memory for storing executable program codes; A processor, configured to call and run the executable program code from the memory so that the vehicle executes the method according to any one of claims 1 to 6.

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