An online method for identifying steering wheel steering ratio

Abstract

This invention relates to an online steering ratio identification method. The method includes: confirming the iterative equation for online steering ratio identification; determining whether the online steering ratio identification conditions are met during vehicle operation; and if the online steering ratio identification conditions are met, performing real-time steering ratio identification processing based on the iterative equation. The online steering ratio identification mechanism provided by this invention improves the accuracy of the steering ratio by enabling real-time identification of changing steering ratios when the starting conditions are met.

Description

Technical Field

[0001] This invention relates to the field of data processing technology, and in particular to an online method for identifying steering wheel ratio. Background Technology

[0002] Steering ratio refers to the ratio of the steering wheel angle to the front wheel angle. Automakers assign a default steering ratio to each vehicle model at the factory. Steering ratio is a commonly used parameter in the control module of an autonomous driving system, and traditionally, the control module uses the manufacturer's default value. However, in practical applications, we have found that the steering ratio is not necessarily consistent between different vehicles of the same model. If the steering ratio used by the control module has a certain degree of error, it will reduce the control accuracy of the module. Summary of the Invention

[0003] The purpose of this invention is to address the shortcomings of existing technologies by providing an online steering ratio identification method, electronic device, and computer-readable storage medium. Based on the correlation between the front wheel angle δ and the vehicle wheelbase l and road curvature k in a bicycle motion model, and the correlation between the front wheel angle δ and the steering wheel angle s, the steering wheel angle zero offset s0, and the steering ratio A, an objective function is constructed. An iterative equation for online steering ratio identification is built by solving the objective function. The initiation conditions for online identification are established based on a speed limit and a steering wheel angle threshold. During vehicle operation, the initiation conditions for online steering ratio identification are judged in real time, and when satisfied, the steering ratio is identified in real time based on the iterative equation. Through the online steering ratio identification mechanism provided by this invention, the accuracy of the steering ratio can be improved by real-time identification of changing steering ratios when the initiation conditions are met; the control module's control accuracy can be improved by using the latest identification results for vehicle control.

[0004] To achieve the above objectives, a first aspect of the present invention provides an online method for identifying steering wheel ratio, the method comprising:

[0005] The iterative equation for online identification of steering ratio is confirmed;

[0006] During vehicle operation, the system determines whether the online steering ratio identification conditions are met.

[0007] If the conditions for online identification of steering ratio are met, then real-time steering ratio identification processing is performed according to the iterative equation.

[0008] Preferably, confirming the iterative equation for online identification of the steering wheel ratio specifically includes:

[0009] Step 21: Denote the relationship between the front wheel angle δ and the vehicle wheelbase l and road curvature k in the bicycle motion model as the corresponding first relationship; denote the relationship between the front wheel angle δ and the steering wheel angle s, the steering wheel angle zero offset s0 and the steering ratio A as the corresponding second relationship; and obtain the third relationship based on the first and second relationships, which can reflect the relationship between the steering ratio A and the steering wheel angle s, the steering wheel angle zero offset s0, the vehicle wheelbase l and road curvature k.

[0010] The first relation is: tanδ=l·k;

[0011] The second relation is: δ=(s-s0) / A;

[0012] The third relation is: (s-s0)=atan(l·k)·A;

[0013] Step 22, based on the total number of existing measurement data n, the measurement data (s) j ,s 0,j ,k j Under the condition of n sets of measurement data (s) j ,s 0,j ,k j The first objective function of the steering ratio least squares problem is constructed using the third relation and the above.

[0014] The first objective function is: 1≤j≤n;

[0015] Step 23: Transform the first objective function.

[0016]

[0017] The transformation result is then used as the corresponding second objective function.

[0018] The second objective function is:

[0019] Step 24, adjust the steering ratio to minimize the second objective function. The corresponding steering ratio is obtained by solving the problem. The expression;

[0020] Steering wheel ratio The expression is:

[0021] Step 25, based on the steering ratio of the steering wheel The expression is derived from the steering wheel ratio. Steering ratio The single-step iterative equation is transformed to obtain the corresponding iterative equation F, specifically:

[0022] Step 251, based on the steering ratio of the steering wheel The expression sets the steering ratio of the steering wheel. The expression;

[0023] Steering wheel ratio The expression is:

[0024] Step 252, adjust the steering ratio of the steering wheel. The expression is transformed to obtain the corresponding first transformed expression.

[0025]

[0026] The first transformation expression is:

[0027] Step 253, sum the historical iteration factors n Set the expression;

[0028] The historical iteration factor sum n The expression is:

[0029] Step 254, adjust the steering ratio of the steering wheel. The expression and the historical iteration factor sum n Substituting the expression into the first transformation expression, we obtain the steering ratio from the steering wheel. Steering ratio The single-step iterative equation is as follows:

[0030]

[0031] Step 255: Determine the iterative equation for online identification of steering wheel steering ratio based on the single-step iterative equation;

[0032] The iterative equation is:

[0033]

[0034] Among them, F t-1 F t The steering ratios at times t-1 and t are respectively; sum t-1 The historical iteration factor at time t, i is the time index; l is the vehicle wheelbase; s t s 0,t and k tLet t be the steering wheel angle, the steering wheel angle zero deviation, and the road curvature.

[0035] Preferably, the determination of whether the online identification condition for the steering ratio is met during vehicle operation specifically includes:

[0036] The system identifies whether the vehicle is in autonomous driving mode. If the vehicle is in autonomous driving mode, the system obtains the current vehicle speed and steering wheel angle, which are recorded as the corresponding first speed and first angle. When the first speed meets the preset speed limit range and the absolute value of the first angle is greater than the preset steering wheel angle threshold, the system determines that the online identification condition for the steering wheel ratio has been met. When the first speed does not meet the speed limit range or the absolute value of the first angle is less than or equal to the steering wheel angle threshold, the system determines that the online identification condition for the steering wheel ratio has not been met.

[0037] Preferably, the iterative equation is:

[0038]

[0039] Among them, F t-1 F t The steering ratios at times t-1 and t are respectively; sum t-1 The historical iteration factor at time t-1 i is the time index, t0 is the initial time of this iteration; l is the vehicle wheelbase; s t s 0,t and k t Let t be the steering wheel angle, the steering wheel angle zero deviation, and the road curvature.

[0040] Preferably, the real-time steering ratio identification process based on the iterative equation specifically includes:

[0041] At the initial time t0, the real-time steering wheel angle, steering wheel angle zero offset, and road curvature are obtained as the corresponding initial steering wheel angle s0 and initial steering wheel angle zero offset s. 0,0 and the initial road curvature k0; and based on the initial steering wheel angle s0 and the initial steering wheel angle zero offset s 0,0 The initial road curvature k0 and the preset vehicle wheelbase l are used to calculate and generate the initial steering ratio F0 corresponding to the initial time t0, and output it; and the initial history iteration factor sum0 corresponding to the initial time t0 is generated based on the initial road curvature k0; wherein,

[0042] F0=(s0-s 0,0 ) / atan(l·k0),

[0043] sum0 = [atan(l·k0)]2 ;

[0044] At the next time t1 after the initial time t0, the real-time steering wheel angle, steering wheel angle zero offset, and road curvature are obtained as the corresponding first steering wheel angle s1 and first steering wheel angle zero offset s. 0,1 and the first road curvature k1; and the first steering wheel angle s1, the first steering wheel angle zero offset s 0,1 Substituting the first road curvature k1, the initial steering ratio F0, and the initial historical iteration factor sum0 into the iterative equation, the first steering ratio F1 corresponding to time t1 is calculated and output; and the first historical iteration factor sum1 corresponding to time t1 is generated based on the initial historical iteration factor sum0 and the first road curvature k1; wherein,

[0045]

[0046] sum1 = sum0 + [atan(l·k1)] 2 ;

[0047] Similarly, at any time t after time t1, the real-time steering wheel angle, steering wheel angle deflection, and road curvature are obtained as the corresponding second steering wheel angle s. t Second steering wheel angle zero deflection s 0,t Second road curvature k t And obtain the steering ratio F of the steering wheel at the previous time t-1. t-1 and historical iteration factor sum t-1 ; and turn the second steering wheel angle s t The second steering wheel angle zero deflection s 0,t The curvature k of the second road t Steering ratio F of the steering wheel at the previous moment t-1 Historical iteration factor sum t-1 Substituting the values ​​into the iterative equation, the second steering ratio F corresponding to time t is calculated. t Output the result; and based on the historical iteration factor sum from the previous time step. t-1 and the curvature k of the second road t Generate the second historical iteration factor sum corresponding to time t. t ;in,

[0048]

[0049] sum t =sum t-1 +[atan(l·k t )] 2 .

[0050] A second aspect of the present invention provides an electronic device, including: a memory, a processor, and a transceiver;

[0051] The processor is used to couple with the memory, read and execute instructions in the memory to implement the steps of the method described in the first aspect above;

[0052] The transceiver is coupled to the processor, and the processor controls the transceiver to send and receive messages.

[0053] A third aspect of the present invention provides a computer-readable storage medium storing computer instructions that, when executed by a computer, cause the computer to perform the instructions described in the first aspect.

[0054] This invention provides an online steering ratio identification method, electronic device, and computer-readable storage medium. Based on the correlation between the front wheel angle δ and the vehicle wheelbase l and road curvature k in a bicycle motion model, and the correlation between the front wheel angle δ and the steering wheel angle s, the steering wheel angle zero offset s0, and the steering ratio A, an objective function is constructed. An iterative equation for online steering ratio identification is constructed by solving the objective function. The initiation conditions for online identification are established based on a speed limit and a steering wheel angle threshold. During vehicle operation, the initiation conditions for online steering ratio identification are judged in real time. When the conditions are met, the steering ratio is identified in real time based on the iterative equation. Through the online steering ratio identification mechanism provided by this invention, the changing steering ratio is identified in real time when the initiation conditions are met, improving the accuracy of the steering ratio. The control module uses the latest identification result output by this invention to control the vehicle, which also improves the control accuracy of the module. Attached Figure Description

[0055] Figure 1 This is a schematic diagram of an online steering ratio identification method provided in Embodiment 1 of the present invention;

[0056] Figure 2 This is a schematic diagram of the structure of an electronic device provided in Embodiment 2 of the present invention. Detailed Implementation

[0057] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0058] The vehicle autonomous driving system, through the online steering ratio identification method provided in Embodiment 1 of the present invention, can confirm whether the vehicle has entered the online steering ratio identification stage, and can identify and output the vehicle's steering ratio in real time when entering the online steering ratio identification stage; Figure 1 This is a schematic diagram of an online steering ratio identification method provided in Embodiment 1 of the present invention, as shown below. Figure 1 As shown, this method mainly includes the following steps:

[0059] Step 1: Confirm the iterative equation for online identification of steering ratio;

[0060] The confirmed iterative equation is:

[0061]

[0062] Among them, F t-1 F t The steering ratios at times t-1 and t are respectively; sum t-1 The historical iteration factor at time t, i is the time index; l is the vehicle wheelbase; s t s 0,t and k t Let be the steering wheel angle, steering wheel angle deflection, and road curvature at time t;

[0063] Here, the autonomous driving system will first confirm the iterative equation used for online identification of steering wheel ratio. Steps 11-15 below are the confirmation process of the iterative equation.

[0064] Specifically, this includes: Step 11, recording the relationship between the front wheel angle δ and the vehicle wheelbase l and road curvature k in the bicycle motion model as the corresponding first relationship; and recording the relationship between the front wheel angle δ and the steering wheel angle s, the steering wheel angle zero offset s0 and the steering wheel ratio A as the corresponding second relationship; and obtaining a third relationship based on the first and second relationships that reflects the relationship between the steering wheel ratio A and the steering wheel angle s, the steering wheel angle zero offset s0, the vehicle wheelbase l and road curvature k;

[0065] The first relation is: tanδ=l·k;

[0066] The second relation is: δ=(s-s0) / A;

[0067] The third relation is: (s-s0)=atan(l·k)·A;

[0068] Here, the front wheel steering angle δ, steering wheel angle s, steering wheel angle zero offset s0, steering ratio A, vehicle wheelbase l, and road curvature k mentioned in this embodiment of the invention are all well-known autonomous driving parameters; the front wheel steering angle δ is the steering angle of the vehicle's front wheels; the steering wheel angle s is the actual steering wheel angle fed back by the vehicle's chassis module; the steering wheel angle zero offset s0 is the steering wheel angle when the front wheel angle is 0 degrees. The steering wheel angle zero offset can be a fixed value or an online identification value output in real time by the autonomous driving system. The online identification method of the steering wheel angle zero offset by the autonomous driving system is not part of the technical specifications of this embodiment of the invention. The technical solution is not discussed further here; the vehicle wheelbase l is a fixed value given by the manufacturer when the vehicle leaves the factory; the road curvature k is the reciprocal of the vehicle's real-time turning radius R, k = 1 / R, and the vehicle's real-time turning radius can be obtained from the vehicle's positioning module; the first and second relations are well-known correlations. From the first relation, δ = atan(l·k) can be derived, and combined with the second relation δ = (s-s0) / A, we can get δ = atan(l·k) = (s-s0) / A, and thus we can naturally get the third relation (s-s0) = atan(l·k)·A;

[0069] Step 12, based on the total number of existing measurement data n, the measurement data (s) j ,s 0,j ,k j Under the condition of n sets of measurement data (s) j ,s 0,j ,k j The first objective function of the steering ratio least squares problem is constructed using the third relation.

[0070] The first objective function is: 1≤j≤n;

[0071] Here, n is a positive integer greater than 1;

[0072] Step 13, transform the first objective function.

[0073]

[0074] The transformation result is then used as the corresponding second objective function.

[0075] The second objective function is:

[0076] Step 14, adjust the steering ratio to minimize the second objective function. The corresponding steering ratio is obtained by solving the problem. The expression;

[0077] Steering ratio The expression is:

[0078] Here, minimizing the second objective function means making Therefore, the steering ratio mentioned above can be obtained naturally. The expression;

[0079] Step 15, based on the steering ratio The expression for the steering wheel ratio Steering ratio The single-step iterative equation is transformed to obtain the corresponding iterative equation F, specifically:

[0080] Step 151, based on the steering ratio The expression sets the steering ratio. The expression;

[0081] Steering ratio The expression is:

[0082] Step 152, adjust the steering ratio. The expression is transformed to obtain the corresponding first transformed expression.

[0083]

[0084]

[0085] The first transformation expression is:

[0086] Step 153, sum the historical iteration factors n Set the expression;

[0087] Historical iteration factor sum n The expression is:

[0088] Step 154, adjust the steering ratio. The expression and the history iteration factor sum n Substituting the expression into the first transformation expression, we obtain the steering wheel ratio. Steering ratio The single-step iterative equation is:

[0089]

[0090] Step 155: Determine the iterative equation for online identification of steering wheel ratio based on the single-step iterative equation;

[0091] The determined iterative equation is:

[0092]

[0093] Among them, F t-1 F t The steering ratios at times t-1 and t are respectively; sum t-1 The historical iteration factor at time t, i is the time index; l is the vehicle wheelbase; s t s 0,t and k t Let t be the steering wheel angle, the steering wheel angle zero deviation, and the road curvature.

[0094] Step 2: Determine whether the online identification conditions for the steering ratio are met during vehicle operation;

[0095] Specifically, this includes: identifying whether the vehicle is in autonomous driving mode; if the vehicle is in autonomous driving mode, obtaining the vehicle speed and steering wheel angle at the current moment and recording them as the corresponding first speed and first angle; and determining that the online identification condition for the steering wheel ratio has been met when the first speed meets the preset speed limit range and the absolute value of the first angle is greater than the preset steering wheel angle threshold; and determining that the online identification condition for the steering wheel ratio has not been met when the first speed does not meet the speed limit range or the absolute value of the first angle is less than or equal to the steering wheel angle threshold.

[0096] Here, this embodiment of the invention presets a speed limit range and a steering wheel angle threshold. The lower speed limit of the speed limit range is 8 km / h by default, and the upper speed limit is 45 km / h by default. Of course, the upper and lower speed limits of the speed limit range can also be configured according to actual application needs. The steering wheel angle threshold is 100 degrees by default, but it can also be configured according to actual application needs. Because the real-time steering ratio error will increase due to the friction damping between the tires and the ground when the vehicle is in a low-speed, large-angle autonomous driving state, the autonomous driving system should continue to execute subsequent steps to start the online identification processing flow provided by this embodiment of the invention. It should be noted that if the vehicle is in an autonomous driving state but the online identification conditions for the steering wheel ratio are not met, the autonomous driving system will stop executing subsequent steps, and the control module will continue to control the vehicle based on the default steering wheel ratio set by the vehicle manufacturer or the value of the steering wheel ratio obtained from the most recent online identification.

[0097] Step 3: If the conditions for online identification of steering ratio are met, then perform real-time steering ratio identification processing according to the iterative equation.

[0098] Specifically, this includes: Step 31, at the initial time t0, acquiring the real-time steering wheel angle, steering wheel angle zero offset, and road curvature as the corresponding initial steering wheel angle s0 and initial steering wheel angle zero offset s 0,0 And the initial road curvature k0; and based on the initial steering wheel angle s0 and the initial steering wheel angle zero offset s 0,0 The initial road curvature k0 and the preset vehicle wheelbase l are used to calculate and generate the initial steering ratio F0 corresponding to the initial time t0, and output it; and the initial history iteration factor sum0 corresponding to the initial time t0 is generated based on the initial road curvature k0; where,

[0099] F0=(s0-s 0,0 ) / atan(l·k0),

[0100] sum0 = [atan(l·k0)] 2 ;

[0101] Here, in this embodiment of the invention, when entering the online identification of the steering ratio, the entry time is taken as the initial time t0 of this iteration; at the initial time t0, since there is no steering ratio F from the previous time, t-1 There is also no historical iteration factor sum from the previous moment. t-1 Therefore, we can directly use the third relation (s-s0) = atan(l·k)·A to calculate the initial steering ratio F0 at the initial time t0, and directly use sum0 = [atan(l·k0)]. 2 The initial historical iteration factor sum0 is calculated; after obtaining the initial steering ratio F0, it is output and saved as the latest identification result; when outputting the initial steering ratio F0, this embodiment of the invention also passes the initial steering ratio F0 and the initial historical iteration factor sum0 to the next time t1 as the corresponding F t-1 ,sum t-1 It should be noted that the initial steering wheel angle s0 obtained in the current step should be the steering wheel angle output by the vehicle chassis module at the current moment.

[0102] Step 32: At the next time t1 after the initial time t0, obtain the real-time steering wheel angle, steering wheel angle zero deviation, and road curvature as the corresponding first steering wheel angle s1 and first steering wheel angle zero deviation s2. 0,1 and the first road curvature k1; and the first steering wheel angle s1, the first steering wheel angle zero offset s 0,1 Substituting the first road curvature k1, the initial steering ratio F0, and the initial historical iteration factor sum0 into the iterative equation, the first steering ratio F1 corresponding to time t1 is calculated and output; and the first historical iteration factor sum1 corresponding to time t1 is generated based on the initial historical iteration factor sum0 and the first road curvature k1; where,

[0103]

[0104] sum1 = sum0 + [atan(l·k1)] 2 ;

[0105] Here, at the next time t1 after the initial time t0, the steering ratio F from the previous time is already known. t-1 =F t0 and historical iteration factor sum t-1 =sum t0 Therefore, the first steering ratio F1 at time t1 can be calculated using iterative equations, and after obtaining the first steering ratio F1, it can be output and saved as the latest identification result; it can be based on The first historical iteration factor sum1 at time t1 is calculated by the accumulation method; when outputting the first steering ratio F1, this embodiment of the invention will also pass the first steering ratio F1 and the first historical iteration factor sum1 to the next time t1 as the corresponding F t-1 ,sum t-1 It should be noted that the first steering wheel angle s1 obtained in the current step should also be the steering wheel angle output by the vehicle chassis module at the current moment.

[0106] Step 33, and so on, at any time t after time t1, obtain the real-time steering wheel angle, steering wheel angle deflection, and road curvature as the corresponding second steering wheel angle s. t Second steering wheel angle zero deflection s 0,t Second road curvature k t And obtain the steering ratio F of the steering wheel at the previous time t-1. t-1 and historical iteration factor sum t-1 ; and turn the second steering wheel angle s t Second steering wheel angle zero deflection s 0,t Second road curvature k t Steering ratio F of the steering wheel at the previous moment t-1 Historical iteration factor sum t-1 Substituting the values ​​into the iterative equation, we can calculate the second steering ratio F corresponding to time t. t Output the result; and based on the historical iteration factor sum from the previous time step. t-1 Second road curvature k t Generate the second historical iteration factor sum corresponding to time t. t ;in,

[0107]

[0108] sum t =sum t-1 +[atan(l·k t )] 2 .

[0109] Here, similar to step 32, at any time t after time t1, the steering ratio F from the previous time is already known. t-1 and historical iteration factor sum t-1 Therefore, the second steering ratio F at time t can be calculated using iterative equations. t And obtain the second steering ratio F t Then output and save it as the latest identification result; it can be based on sum. t =sum t-1 +[atan(l·k t )] 2 The second historical iteration factor sum at time t is calculated using the accumulation method. t ; Output the second steering wheel ratio F t In this embodiment of the invention, the second steering wheel steering ratio F will also be adjusted. t Second historical iteration factor sum t Passed to the next moment as the new F t-1 ,sum t-1 It should be noted that the second steering wheel angle s obtained in the current step t It should also be the steering wheel angle output by the vehicle chassis module at the current moment.

[0110] In summary, when the initiation conditions for online identification of steering ratio are met, the autonomous driving system of this embodiment can output the steering ratio in real time through step 3 above, thereby reducing the error between the parameter value of the steering ratio used in the system and the true value, and improving the accuracy of the steering ratio; the control module controls the vehicle based on the latest identification result output in real time in step 3 above, which naturally improves the control accuracy of the module.

[0111] Figure 2 This is a schematic diagram of an electronic device provided in Embodiment 2 of the present invention. This electronic device can be the aforementioned terminal device or server, or it can be a terminal device or server connected to the aforementioned terminal device or server that implements the method of the embodiments of the present invention. Figure 2As shown, the electronic device may include: a processor 301 (e.g., CPU), a memory 302, and a transceiver 303; the transceiver 303 is coupled to the processor 301, and the processor 301 controls the transmission and reception operations of the transceiver 303. The memory 302 may store various instructions for performing various processing functions and implementing the processing steps described in the foregoing method embodiments. Preferably, the electronic device involved in the embodiments of the present invention further includes: a power supply 304, a system bus 305, and a communication port 306. The system bus 305 is used to realize communication connections between components. The communication port 306 is used for communication between the electronic device and other peripherals.

[0112] exist Figure 2 The system bus 305 mentioned can be a Peripheral Component Interconnect (PCI) bus or an Extended Industry Standard Architecture (EISA) bus, etc. This system bus can be divided into address bus, data bus, control bus, etc. For ease of representation, it is represented by only one thick line in the figure, but this does not indicate that there is only one bus or one type of bus. The communication interface is used to enable communication between the database access device and other devices (e.g., clients, read-write libraries, and read-only libraries). Memory may include Random Access Memory (RAM) and may also include non-volatile memory, such as at least one disk storage device.

[0113] The processors mentioned above can be general-purpose processors, including central processing units (CPUs), network processors (NPs), graphics processing units (GPUs), etc.; they can also be digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components.

[0114] It should be noted that the embodiments of the present invention also provide a computer-readable storage medium storing instructions that, when run on a computer, cause the computer to perform the methods and processes provided in the above embodiments.

[0115] This invention also provides a chip for executing instructions, which is used to perform the processing steps described in the foregoing method embodiments.

[0116] This invention provides an online steering ratio identification method, electronic device, and computer-readable storage medium. Based on the correlation between the front wheel angle δ and the vehicle wheelbase l and road curvature k in a bicycle motion model, and the correlation between the front wheel angle δ and the steering wheel angle s, the steering wheel angle zero offset s0, and the steering ratio A, an objective function is constructed. An iterative equation for online steering ratio identification is constructed by solving the objective function. The initiation conditions for online identification are established based on a speed limit and a steering wheel angle threshold. During vehicle operation, the initiation conditions for online steering ratio identification are judged in real time. When the conditions are met, the steering ratio is identified in real time based on the iterative equation. Through the online steering ratio identification mechanism provided by this invention, the changing steering ratio is identified in real time when the initiation conditions are met, improving the accuracy of the steering ratio. The control module uses the latest identification result output by this invention to control the vehicle, which also improves the control accuracy of the module.

[0117] Those skilled in the art will further recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this invention.

[0118] The steps of the methods or algorithms described in conjunction with the embodiments disclosed herein can be implemented in hardware, a software module executed by a processor, or a combination of both. The software module can be located in random access memory (RAM), main memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disk, removable disk, CD-ROM, or any other form of storage medium known in the art.

[0119] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An online method for identifying steering wheel steering ratio, characterized in that, The method includes: The iterative equation for online identification of steering ratio is confirmed; During vehicle operation, the system determines whether the online steering ratio identification conditions are met. If the conditions for online identification of steering ratio are met, then real-time steering ratio identification processing is performed according to the iterative equation. The iterative equation is: Among them, F t-1 F t The steering ratios at times t-1 and t are respectively; sum t-1 The historical iteration factor at time t-1 i is the time index, t0 is the initial time of this iteration; l is the vehicle wheelbase; s t s 0,t and k t Let be the steering wheel angle, steering wheel angle deflection, and road curvature at time t; The determination of whether the online identification conditions for the steering ratio are met during vehicle operation specifically includes: The system identifies whether the vehicle is in autonomous driving mode. If the vehicle is in autonomous driving mode, the system obtains the current vehicle speed and steering wheel angle, which are recorded as the corresponding first speed and first angle. When the first speed meets the preset speed limit and the absolute value of the first angle is greater than the preset steering wheel angle threshold, the system determines that the online identification condition for the steering wheel ratio has been met. When the first speed does not meet the speed limit or the absolute value of the first angle is less than or equal to the steering wheel angle threshold, the system determines that the online identification condition for the steering wheel ratio has not been met. The real-time steering ratio identification process based on the iterative equation specifically includes: At the initial time t0, the real-time steering wheel angle, steering wheel angle zero offset, and road curvature are obtained as the corresponding initial steering wheel angle s0 and initial steering wheel angle zero offset s. 0,0 and the initial road curvature k0; and based on the initial steering wheel angle s0 and the initial steering wheel angle zero offset s 0,0 The initial road curvature k0 and the preset vehicle wheelbase l are used to calculate and generate the initial steering ratio F0 corresponding to the initial time t0, and output it; and the initial history iteration factor sum0 corresponding to the initial time t0 is generated based on the initial road curvature k0; wherein, F0=(s0-s 0,0 ) / atan(l·k0), sum0[atan(l·k0)] 2 100. At the next time t1 after the initial time t0, the real-time steering wheel angle, steering wheel angle zero offset, and road curvature are obtained as the corresponding first steering wheel angle s1 and first steering wheel angle zero offset s. 0,1 and the first road curvature k1; and the first steering wheel angle s1, the first steering wheel angle zero offset s 0,1 Substituting the first road curvature k1, the initial steering ratio F0, and the initial historical iteration factor sum0 into the iterative equation, the first steering ratio F1 corresponding to time t1 is calculated and output; and the first historical iteration factor sum1 corresponding to time t1 is generated based on the initial historical iteration factor sum0 and the first road curvature k1; wherein, sum1=sum0+[atan(l·k1)] 2 ; Similarly, at any time t after time t1, the real-time steering wheel angle, steering wheel angle deflection, and road curvature are obtained as the corresponding second steering wheel angle s. t Second steering wheel angle zero deflection s 0,t Second road curvature k t And obtain the steering ratio F of the previous time step t-1. t-1 and historical iteration factor sum t-1 ; and turn the second steering wheel angle s t The second steering wheel angle zero deflection s 0,t The curvature k of the second road t Steering ratio F of the steering wheel at the previous moment t-1 Historical iteration factor sum t-1 Substituting the values ​​into the iterative equation, the second steering ratio F corresponding to time t is calculated. t Output the result; and based on the historical iteration factor sum from the previous time step. t-1 and the curvature k of the second road t Generate the second historical iteration factor sum corresponding to time t. t ;in, as t =sum t-1 +[attan(l·k t )] 2 。 2. The online identification method for steering wheel ratio according to claim 1, characterized in that, The confirmation of the iterative equation for online identification of the steering ratio specifically includes: Step 21: Denote the relationship between the front wheel angle δ and the vehicle wheelbase l and road curvature k in the bicycle motion model as the corresponding first relationship; denote the relationship between the front wheel angle δ and the steering wheel angle s, the steering wheel angle zero offset s0 and the steering ratio A as the corresponding second relationship; and obtain the third relationship based on the first and second relationships, which can reflect the relationship between the steering ratio A and the steering wheel angle s, the steering wheel angle zero offset s0, the vehicle wheelbase l and road curvature k. The first relation is: tanδ=l·k; The second relation is: δ=(s-s0) / A; The third relation is: (s-s0)=atan(l·k)·A; Step 22, based on the total number of existing measurement data n, the measurement data (s) j ,s 0,j ,k j Under the condition of n sets of measurement data (s) j ,s 0,j ,k j The first objective function of the steering ratio least squares problem is constructed using the third relation and the above. The first objective function is: 1≤j≤n; Step 23: Transform the first objective function. ， The transformation result is then used as the corresponding second objective function. The second objective function is: Step 24, adjust the steering ratio to minimize the second objective function. The corresponding steering ratio is obtained by solving the problem. The expression; Steering wheel ratio The expression is: Step 25, based on the steering ratio of the steering wheel The expression is derived from the steering wheel ratio. Steering ratio The single-step iterative equation is transformed to obtain the corresponding iterative equation F, specifically: Step 251, based on the steering ratio of the steering wheel The expression sets the steering ratio of the steering wheel. The expression; Steering wheel ratio The expression is: Step 252, adjust the steering ratio of the steering wheel. The expression is transformed to obtain the corresponding first transformed expression. The first transformation expression is: Step 253, sum the historical iteration factors n Set the expression; The historical iteration factor sum n The expression is: Step 254, adjust the steering wheel ratio. The expression and the historical iteration factor sum n Substituting the expression into the first transformation expression, we obtain the steering ratio from the steering wheel. Steering ratio The single-step iterative equation is: Step 255: Determine the iterative equation for online identification of steering wheel steering ratio based on the single-step iterative equation; The iterative equation is: Among them, F t-1 F t The steering ratios at times t-1 and t are respectively; sum t-1 The historical iteration factor at time t, i is the time index; l is the vehicle wheelbase; s t s 0,t and k t Let t be the steering wheel angle, the steering wheel angle zero deviation, and the road curvature.

3. An electronic device, characterized in that, include: Memory, processor, and transceiver; The processor is configured to be coupled to the memory, read and execute instructions in the memory to implement the method according to any one of claims 1-2; The transceiver is coupled to the processor, and the processor controls the transceiver to send and receive messages.

4. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer instructions that, when executed by a computer, cause the computer to perform the method described in any one of claims 1-2.

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