Method, device, equipment and medium for determining rack force of vehicle

Abstract

The present invention discloses a method, device, equipment and medium for determining the rack force of a vehicle. The method comprises: obtaining a steering lever arm of a steering system of the vehicle; obtaining a steering friction torque of the steering system; obtaining a gravity return torque of the steering system; and determining the rack force of the steering system based on the steering lever arm, the steering friction torque and the gravity return torque.

Description

Technical Field

[0001] The present invention relates to the field of vehicle technology, and in particular to a method, device, equipment and medium for determining a rack force of a vehicle. Background Art

[0002] In the early stage of vehicle steering system development, accurate rack force is crucial for the selection of power steering system and power steering system. However, the traditional method of calculating vehicle rack force in practical applications is not accurate enough. Summary of the invention

[0003] Based on the above problems, embodiments of the present invention provide a method, device, equipment and medium for determining the rack force of a vehicle.

[0004] The technical solution provided by the embodiment of the present invention is as follows:

[0005] An embodiment of the present invention provides a method for determining a rack force of a vehicle, the method comprising:

[0006] Obtaining a steering arm of a steering system of the vehicle;

[0007] Obtaining a steering friction torque of the steering system;

[0008] Obtaining the gravity return torque of the steering system;

[0009] A rack force of the steering system is determined based on the steering arm, the steering friction torque, and the gravity return torque.

[0010] In some embodiments, determining the rack force of the steering system based on the steering arm, the steering friction torque and the gravity return torque includes:

[0011] Counting the gravity self-aligning torque and the steering friction torque to obtain torque statistics results;

[0012] The torque statistics and the steering arm are processed to determine the rack force.

[0013] In some embodiments, obtaining the steering lever arm of the steering system includes:

[0014] The steering arm is obtained based on a first parameter and a second parameter; wherein the first parameter includes a distance parameter between a left steering tie rod axis and a kingpin axis; and the second parameter includes a distance parameter between a right steering tie rod axis and the kingpin axis.

[0015] In some embodiments, obtaining the steering arm based on the first parameter and the second parameter includes:

[0016] Performing a cross product calculation on the first parameter and the second parameter to obtain a third parameter;

[0017] Performing a sum calculation on the first parameter and the second parameter to obtain a fourth parameter;

[0018] The third parameter and the fourth parameter are processed to determine the steering arm.

[0019] In some embodiments, obtaining the gravity return torque of the steering system includes:

[0020] Obtaining the front axle load, tire diameter, kingpin parameter and inner wheel turning angle of the vehicle;

[0021] The front axle load, the tire diameter, the kingpin parameter, and the inner wheel turning angle are processed to obtain the gravity self-aligning torque.

[0022] In some embodiments, obtaining the steering friction torque of the steering system includes:

[0023] Obtaining the front axle load and tire contact parameters of the vehicle;

[0024] The steering friction torque is determined based on the front axle load and the tire contact contact parameter.

[0025] In some embodiments, the tire contact parameters include tire contact patch width and tire contact patch length; and determining the steering friction torque based on the front axle load and the tire contact parameters includes:

[0026] determining tire friction for tires of the vehicle based on the front axle load;

[0027] Processing the tire contact patch width and the tire contact patch length to obtain tire footprint parameters;

[0028] The tire friction force and the tire footprint parameters are processed to determine the steering friction torque.

[0029] An embodiment of the present invention further provides a rack force determination device for a vehicle, the device comprising:

[0030] An acquisition module, used for acquiring a steering arm, a steering friction torque and a gravity return torque of a steering system of the vehicle;

[0031] A determination module is used to determine the rack force based on the steering arm, the steering friction torque and the gravity return torque.

[0032] An embodiment of the present invention also provides a rack force determination device for a vehicle, the device comprising a processor, a memory, a communication interface and a communication bus; the processor, the memory and the communication interface communicate with each other via the communication bus; the memory is used to store at least one executable instruction; the executable instruction enables the processor to execute any of the rack force determination methods for a vehicle as described above.

[0033] An embodiment of the present invention further provides a computer-readable storage medium, wherein the storage medium stores at least one executable instruction; the executable instruction enables a processor to execute any of the above-described methods for determining the rack force of a vehicle.

[0034] In the method for determining the rack force of a vehicle provided in an embodiment of the present invention, the gravity return torque and steering friction torque of the steering system can comprehensively reflect the obstruction state of the steering system during the steering operation, and the steering lever arm can characterize the actual steering state of the steering system. That is to say, the steering lever arm, steering friction torque and gravity return torque of the steering system are directly related to each steering operation of the steering system of the vehicle. Therefore, the rack force of the steering system determined based on the steering lever arm, steering friction torque and gravity return lever arm of the steering system must be consistent with the actual steering state and steering performance of the steering system, thereby improving the accuracy of the rack force of the steering system and meeting the needs of power-assist module selection and matching. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 A schematic flow chart of a method for determining rack force of a vehicle provided by an embodiment of the present invention;

[0036] Figure 2A A schematic diagram of the structure of a left-turn left limit steering arm provided in an embodiment of the present invention;

[0037] Figure 2B A schematic diagram of the structure of a right-turn right limit steering lever arm provided in an embodiment of the present invention;

[0038] Figure 3 Another schematic flow chart of a method for determining a rack force of a vehicle provided by an embodiment of the present invention;

[0039] Figure 4 A schematic diagram of a structure for determining a rack force of a vehicle provided by an embodiment of the present invention;

[0040] Figure 5 A schematic diagram of the structure of a rack force determination device for a vehicle provided by an embodiment of the present invention;

[0041] Figure 6 A schematic structural diagram of a rack force determination device for a vehicle provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0042] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0043] It should be understood that the specific embodiments described herein are only used to explain the present invention, and are not used to limit the present invention.

[0044] During the vehicle development process, in the early stages of the development of the steering system for the entire vehicle project, there is no real vehicle to test and verify the maximum rack force of the steering system, making it impossible to provide accurate data basis for the selection and matching of the power system or power assistance model.

[0045] In practical applications, the maximum rack force of the steering system is the data basis for the selection and matching of the power module and the power system. If the maximum rack force accuracy of the steering system is insufficient, if the power and torque of the power module are too small, the steering requirements of the steering system cannot be met. If the power and torque of the power module are too large, it will lead to waste of resources of the steering system, thereby increasing unnecessary costs and hindering the smooth progress of the early research and development of the steering system. Therefore, the accurate calculation of the rack force of the steering system is crucial to the selection and matching of the power system and the power module.

[0046] Some methods for calculating the maximum rack force of a steering system have been proposed in the related art. However, the accuracy of the rack force obtained by these methods is relatively poor and cannot meet the requirements for the selection and matching of power-assist modules.

[0047] Based on the above problems, an embodiment of the present invention provides a method, device, equipment and medium for determining the rack force of a vehicle. The method for determining the rack force of a vehicle provided by an embodiment of the present invention can obtain the steering arm, steering friction torque and gravity return torque of the steering system of the vehicle, and determine the rack force based on the steering arm, steering friction torque and gravity return torque. Therefore, the method for determining the rack force of a vehicle provided by an embodiment of the present invention can determine the rack force of the steering system through the steering arm, steering friction torque and gravity return torque directly associated with each actual steering operation of the steering system, thereby greatly improving the accuracy of the rack force of the steering system.

[0048] It should be noted that the rack force determination method of a vehicle provided in an embodiment of the present invention can be implemented by a processor of an electronic device, and the above-mentioned processor can be at least one of an application specific integrated circuit (Application Specific Integrated Circuit, ASIC), a digital signal processor (Digital Signal Processor, DSP), a digital signal processing device (Digital Signal Processing Device, DSPD), a programmable logic device (Programmable Logic Device, PLD), a field programmable gate array (Field Programmable Gate Array, FPGA), a central processing unit (Central Processing Unit, CPU), a controller, a microcontroller, and a microprocessor.

[0049] Figure 1 A schematic flow chart of a method for determining a rack force of a vehicle provided by an embodiment of the present invention is shown in FIG. Figure 1 As shown, the process may include steps 101 to 104:

[0050] Step 101: Obtain the steering arm of the vehicle's steering system.

[0051] Exemplarily, the processor of the electronic device may obtain a steering arm of a steering system of the vehicle.

[0052] Exemplarily, the steering system of a vehicle is used to control the driving direction of the vehicle in real time.

[0053] Exemplarily, the steering system of a vehicle may include a mechanical steering system and a power steering system; wherein the mechanical steering system includes a steering system that requires manual operation by the driver to achieve the steering function, and the power steering system includes a steering system that achieves the steering function with the help of power provided by the vehicle; wherein the power steering system can be further divided into a hydraulic power steering system, an electric power steering system and a pneumatic power steering system.

[0054] Exemplarily, the steering system of the vehicle may include a steering wheel, a steering shaft, a steering intermediate shaft, a steering oil pipe, a steering oil pump, a steering oil tank, a steering arm, a steering tie rod, a steering rocker arm, an integral steering gear, a steering tie rod and a steering damper, etc.

[0055] In one embodiment, the steering lever arm may include the distance that the steering arm of the steering system rotates in the rotation direction; exemplary, the steering lever arm may be related to the rotation angle of the steering arm and the length of the steering arm; exemplary, the steering lever arm may be determined by at least one of the structure, type, and vehicle type of the steering system.

[0056] Step 102: Obtain the steering friction torque of the steering system.

[0057] Exemplarily, the processor of the electronic device may obtain the steering friction torque of the steering system.

[0058] Exemplarily, the steering friction torque may be the product of the steering friction force and the distance of action of the steering friction force; wherein the steering friction force is an important factor affecting the steering performance of the vehicle.

[0059] Step 103: Obtain the gravity self-aligning torque of the steering system.

[0060] Exemplarily, a processor of the electronic device may obtain the gravity-correcting torque.

[0061] Exemplarily, the gravity righting moment may include the righting moment generated by the vehicle's own gravity when the vehicle is unloaded; exemplary, the gravity righting moment may include the righting moment generated by the vehicle's own gravity and the vehicle load when the vehicle is fully loaded.

[0062] Exemplarily, the execution order of step 101 to step 103 may be adjusted sequentially or performed in parallel, which is not limited in the embodiment of the present invention.

[0063] Step 104: Determine the rack force of the steering system based on the steering arm, the steering friction torque, and the gravity return torque.

[0064] For example, the processor of the electronic device may determine the rack force of the steering system based on the steering lever arm, the steering friction torque, and the gravity return torque.

[0065] In one embodiment, the rack force of the steering system may include a rack force range of the steering system; illustratively, the rack force may include a maximum rack force of the steering system.

[0066] Exemplarily, a rack force calculation algorithm can be determined, and then the steering arm, steering friction torque and gravity return torque are processed through the rack force calculation algorithm to determine the rack force of the steering system; exemplary, the rack force calculation algorithm can be adjusted according to at least one of the type and function of the vehicle and the structural composition of the steering system, which is not limited to the embodiments of the present invention.

[0067] From the above, it can be seen that in the method for determining the rack force of a vehicle provided in an embodiment of the present invention, after obtaining the steering lever arm, steering friction torque and gravity restoring torque of the vehicle's steering system, the rack force of the steering system can be determined based on the steering lever arm, steering friction torque and gravity restoring torque.

[0068] Therefore, in the method for determining the rack force of a vehicle provided in an embodiment of the present invention, the gravity return torque and steering friction torque of the steering system can directly reflect the obstructed state of the steering system during the steering operation, and the steering lever arm can characterize the actual steering state of the steering system. That is to say, the steering lever arm, steering friction torque and gravity return torque of the steering system are directly related to each steering operation of the steering system of the vehicle. Then, the rack force of the steering system determined based on the steering lever arm, steering friction torque and gravity return torque of the steering system must be consistent with the actual steering state and steering performance of the steering system, thereby improving the accuracy of the rack force of the steering system and meeting the needs of power-assist module selection and matching.

[0069] Based on the above embodiments, in the method for determining the rack force of a vehicle provided in the embodiment of the present invention, the rack force of the steering system is determined based on the steering arm, the steering friction torque and the gravity return torque, which can be achieved in the following manner:

[0070] The gravity self-aligning torque and the steering friction torque are counted to obtain the torque statistics results; the torque statistics results and the steering arm are processed to determine the rack force.

[0071] Exemplarily, the processor of the electronic device may perform statistics on the gravity self-aligning torque and the steering friction torque to obtain torque statistics results, and process the torque statistics results and the steering lever arm to determine the rack force.

[0072] In one embodiment, the factors in the steering friction torque whose influence on the gravity restoring torque is greater than or equal to the influence threshold can be analyzed, and the gravity restoring torque and the steering friction torque can be statistically analyzed based on the factors, so as to weaken the above factors in the steering friction torque, and determine the above statistical results as the torque statistical results.

[0073] Exemplarily, the gravity restoring torque and the steering friction torque can be statistically averaged, and the result of the statistical average processing can be used to determine the torque statistical result; exemplary, the torque statistical result can still be the torque; exemplary, the gravity restoring torque and the steering torque can be summed and calculated, and the summed result can be determined as the torque statistical result.

[0074] Exemplarily, according to the relationship between the torque and the lever arm, the quotient of the torque statistical result and the steering lever arm can be determined as the rack force.

[0075] For example, the rack force F can be calculated by formula (1): R :

[0076]

[0077] In formula (1), T Bis the gravity self-aligning torque, T F is the steering friction torque, and T B +T F is the moment statistics result; L E For the steering arm.

[0078] From the above, it can be seen that in the rack force determination method of the steering system provided in the embodiment of the present invention, the gravity return torque and the steering friction torque can be statistically analyzed, and after the torque statistical results are obtained, the torque statistical results and the steering lever arm are processed to determine the rack force.

[0079] Since the gravity righting torque can accurately characterize the steering resistance of the steering system caused by various load states of the vehicle, and the steering friction torque can characterize the steering resistance of the steering system caused by the surface supporting the vehicle when the vehicle is under a load state, the torque statistical results obtained by statistically analyzing the gravity righting torque and the steering friction torque can accurately and comprehensively characterize the resistance encountered by the vehicle's steering system during the righting process, thereby greatly improving the accuracy of the torque statistical results and the rack force determined by processing the steering arm.

[0080] Based on the above embodiments, in the method for determining the rack force of a vehicle provided in the embodiment of the present invention, obtaining the steering arm of the steering system of the vehicle can be achieved in the following manner:

[0081] The steering arm is obtained based on the first parameter and the second parameter.

[0082] The first parameter includes a distance parameter between the left steering tie rod axis and the kingpin axis; the second parameter includes a distance parameter between the right steering tie rod axis and the kingpin axis.

[0083] Exemplarily, the processor of the electronic device may obtain the steering arm based on the first parameter and the second parameter.

[0084] In one embodiment, the first parameter may include the extreme distance between the left steering rod axis and the kingpin axis due to steering. Exemplarily, the first parameter may be the left steering extreme distance between the left steering rod axis and the kingpin axis; Exemplarily, the first parameter may be the left turn extreme steering arm, wherein, when the left steering rod axis and the kingpin axis are in a relative position of a left turn extreme state, the angle between the left turn extreme steering arm and the kingpin axis, and the angle between the left turn extreme steering arm and the left steering rod axis may both be 90 degrees.

[0085] Figure 2A The schematic diagram of the structure of the left-turn left limit steering arm provided by the embodiment of the present invention is as follows: Figure 2AAs shown, when the kingpin axis 201 and the left steering rod axis 202 are in the left steering limit state, the angle 204 between the kingpin axis 201 and the left turn left limit steering arm 203 is 90 degrees, and the angle 204 between the left steering rod axis 202 and the left turn left limit steering arm 203 is also 90 degrees.

[0086] In one embodiment, the second parameter may include the extreme distance between the right steering rod axis and the kingpin axis due to steering. Exemplarily, the second parameter may be the right steering extreme distance between the right steering rod axis and the kingpin axis; Exemplarily, the second parameter may be the right turn right extreme steering lever arm, wherein, when the right steering rod axis and the kingpin axis are in a relative position of a right turn extreme state, the angle between the right turn right extreme steering lever arm and the kingpin axis, and the angle between the right turn right extreme steering lever arm and the right steering rod axis may both be 90 degrees.

[0087] Figure 2B The schematic diagram of the structure of the right-turn right limit steering arm provided by the embodiment of the present invention is as follows: Figure 2B As shown, when the kingpin axis 201 and the right steering rod axis 205 are in the right steering limit state, the angle 207 between the kingpin axis 201 and the right turn right limit steering arm 206 is 90 degrees, and the angle 207 between the right steering rod axis 205 and the right turn right limit steering arm 206 is also 90 degrees.

[0088] In one embodiment, the first parameter and the second parameter can be integrated and the integration result can be determined as a steering lever arm. At this time, the steering lever arm can reflect the steering performance of the steering system from at least two dimensions; exemplarily, a lever arm calculation algorithm can be determined, and the first parameter and the second parameter can be processed by the lever arm calculation algorithm to determine the steering lever arm; exemplarily, the steering lever arm can be an effective steering lever arm.

[0089] From the above, it can be seen that in the method for determining the rack force of a vehicle provided in an embodiment of the present invention, the first parameter includes the distance parameter between the left steering rod axis and the kingpin axis, the second parameter includes the distance parameter between the right steering rod axis and the kingpin axis, and the steering arm can be determined based on the first parameter and the second parameter.

[0090] Therefore, in the method for determining the rack force of a vehicle provided in an embodiment of the present invention, the steering lever arm determined based on the first parameter and the second parameter can comprehensively and accurately include the steering performance of the vehicle's steering system in all directions and angles, thereby improving the accuracy of the steering lever arm.

[0091] Based on the above embodiment, in the method for determining the rack force of a vehicle provided in the embodiment of the present invention, obtaining the steering arm based on the first parameter and the second parameter can be achieved through steps A1 to A3:

[0092] Step A1: perform cross multiplication calculation on the first parameter and the second parameter to obtain a third parameter.

[0093] Exemplarily, the processor of the electronic device may perform a cross product calculation on the first parameter and the second parameter to obtain a third parameter.

[0094] Exemplarily, multiple groups of first parameters and second parameters can be obtained, and cross product calculations can be performed on the first parameters and second parameters in each group to obtain multiple cross product results, which are then statistically averaged and the statistical average result is determined as the third parameter.

[0095] Exemplarily, after performing the cross product calculation on the first parameter and the second parameter, the result of the cross product calculation may be weighted, and the weighted result may be determined as the third parameter.

[0096] Step A2: sum the first parameter and the second parameter to obtain a fourth parameter.

[0097] Exemplarily, the processor of the electronic device may perform a sum calculation on the first parameter and the second parameter to obtain a fourth parameter.

[0098] Exemplarily, a weight coefficient may be determined, and based on the weight coefficient, a weighted sum of the first parameter and the second parameter may be performed to obtain a fourth parameter; exemplary, the first parameter and the second parameter may be directly summed, and the result of the summation may be determined as the fourth parameter.

[0099] Step A3: Process the third parameter and the fourth parameter to determine the steering arm.

[0100] Exemplarily, the processor of the electronic device may process the third parameter and the fourth parameter to determine the steering arm.

[0101] Exemplarily, a steering arm calculation algorithm may be determined, and then the third parameter and the fourth parameter are processed by the steering arm calculation algorithm to determine the steering arm.

[0102] For example, the steering arm L E It can be calculated by formula (2):

[0103]

[0104] In formula (2), L L Can be the first parameter, L RCan be the second parameter; 2×L L ×L R Can be the third parameter, L L +L R Can be the fourth parameter.

[0105] From the above, it can be seen that in the method for determining the rack force of a vehicle provided in an embodiment of the present invention, after performing a cross product calculation on the first parameter and the second parameter to obtain the third parameter and performing a sum calculation on the first parameter and the second parameter to obtain the fourth parameter, the third parameter and the fourth parameter can be processed to determine the steering arm.

[0106] Since the first parameter and the second parameter can comprehensively and accurately include the steering performance of the vehicle's steering system in all directions and angles, the steering lever arm determined by performing the above processing on the first parameter and the second parameter can not only accurately reflect the dynamic change process of the lever arm of the vehicle's steering system during the steering process, but also obtain the maximum steering lever arm of the vehicle's steering system, thereby laying a data foundation for improving the rack force accuracy.

[0107] Based on the above embodiments, in the method for determining the rack force of a vehicle provided in the embodiment of the present invention, obtaining the gravity return torque of the steering system can be achieved in the following manner:

[0108] The front axle load, tire diameter, kingpin parameters and inner wheel turning angle of the vehicle are obtained; the front axle load, tire diameter, kingpin parameters and inner wheel turning angle are processed to obtain the gravity self-aligning torque.

[0109] Exemplarily, the processor of the electronic device can obtain the front axle load, tire diameter, kingpin parameters and inner wheel turning angle of the vehicle, and can also process the front axle load, tire diameter, kingpin parameters and inner wheel turning angle to obtain the gravity righting torque.

[0110] In one embodiment, the front axle load may include load values ​​of the vehicle under various load conditions; exemplarily, the tire diameter may include the diameter of the front tire of the vehicle, and the unit may be meter; exemplarily, the kingpin parameters may include the kingpin inclination angle and the kingpin offset distance; exemplarily, the inner wheel turning angle may include the maximum turning angle of the inner wheel.

[0111] For example, the front axle load, tire diameter, kingpin parameter, and inner wheel angle may be comprehensively processed in combination with factors such as the structure of the vehicle and / or the roughness of the surface supporting the vehicle to obtain the gravity righting torque.

[0112] For example, the gravity return moment T B It can be obtained by formula (3):

[0113]

[0114] Where G is the front axle load of the vehicle in Newton (N), D is the tire diameter in meters, σ is the kingpin inclination angle, Dy is the kingpin offset distance, and θ is the maximum inner wheel turning angle.

[0115] From the above, it can be seen that in the method for determining the rack force of a vehicle provided in an embodiment of the present invention, after obtaining the front axle load, tire diameter, kingpin parameters and inner wheel turning angle of the vehicle, the front axle load, tire diameter, kingpin parameters and inner wheel turning angle can be processed to obtain a gravity self-alignment matrix.

[0116] Therefore, in the vehicle rack force determination method provided by the embodiment of the present invention, in the process of calculating the gravity righting torque, a variety of factors that may affect the vehicle's gravity righting torque are added, so that the gravity righting torque can comprehensively reflect the influence state and influence degree of various performance parameters of the vehicle on the gravity righting process, thereby improving the comprehensiveness and accuracy of the gravity righting torque.

[0117] Based on the above embodiments, in the method for determining the rack force of a vehicle provided in the embodiment of the present invention, obtaining the steering friction torque of the steering system can be achieved in the following manner:

[0118] The front axle load and tire contact parameters of the vehicle are obtained; and the steering friction torque is determined based on the front axle load and the tire contact parameters.

[0119] Exemplarily, the processor of the electronic device may obtain the front axle load and tire contact parameters of the vehicle, and determine the steering friction torque based on the front axle load and the tire contact parameters.

[0120] Exemplarily, the tire contact parameters may include parameters of the contact state between the front wheels of the vehicle and the supporting surface of the vehicle; exemplary, the tire contact parameters may be related to at least one of the roughness of the supporting surface of the vehicle, the inclination of the supporting surface, the concave-convexity of the supporting surface, the load state of the vehicle such as the front axle load, and the tire structure size of the vehicle.

[0121] Exemplarily, the correlation relationship between the mutual influence of the front axle load and the tire contact parameters can be obtained, and then the front axle load and the tire contact parameters can be adjusted based on the correlation relationship to determine the steering friction torque; exemplary, the tire contact parameters corresponding to various front axle loads can be determined based on the degree of influence of the front axle load on the tire contact parameters in the correlation relationship, and a series of steering friction torques corresponding to various front axle loads and their associated tire contact parameters can be calculated.

[0122] It can be seen from the above that in the method for determining the rack force of a vehicle provided in the embodiment of the present invention, the front axle load and tire contact parameters of the vehicle can be obtained, and the steering friction torque can be determined based on the front axle load and tire contact parameters.

[0123] Therefore, in the method for determining the rack force of a vehicle provided in an embodiment of the present invention, the process of determining the steering friction torque includes two factors: the front axle load of the vehicle and the tire contact parameters, so that the steering friction torque not only includes the two factors of the front wheel load and the tire contact parameters, but also includes the influence of the interaction between the above two factors on the steering friction torque, so that the steering friction torque can comprehensively and accurately reflect the state of the friction force that the steering system of the vehicle is subjected to during the steering process.

[0124] Based on the above-mentioned embodiment, in the method for determining the rack force of a vehicle provided by the embodiment of the present invention, the tire contact parameters include the tire contact patch width and the tire contact patch length.

[0125] In one embodiment, the tire contact patch width and the tire contact patch length may be closely related to factors such as the tire type, structure, size, tire weight, vehicle weight, vehicle load, and tire pressure; illustratively, when any of the above factors changes, the tire contact patch width and the tire contact patch length may change accordingly.

[0126] For example, multiple sets of tire contact patch widths and tire contact patch lengths may be obtained according to different vehicle weights, vehicle load states, and vehicle tire pressures.

[0127] For example, the tire contact patch length may be related to factors such as tire diameter, tire radial deformation, tire contact patch width, and tire type.

[0128] Exemplarily, the tire contact patch length L can be calculated by formula (4):

[0129]

[0130] Where D is the tire diameter, in meters; δ is the tire radial deformation, in centimeters (cm); δ can be calculated using formula (5):

[0131]

[0132] Among them, C1 is a parameter related to tire design. For example, if the tire type is a bias tire, its value can be 1.15, and if the tire type is a radial tire, its value can be 1.5; B is the tire contact patch width, and its unit can be centimeters (cm); p is the tire pressure, and its unit is 100Kpa; K0 is the coefficient; G is the vehicle front axle load.

[0133] Among them, G can be calculated by formula (6):

[0134] G=M×g (6)

[0135] Where M is the front axle load weight of the vehicle in kilograms (Kg), and g is the acceleration due to gravity in m / s 2 .

[0136] Among them, K0 can be calculated by formula (7):

[0137] K0=0.015×B+0.42 (7)

[0138] Exemplarily, obtaining the steering friction torque based on the front axle load and the tire contact parameters can be achieved through steps B1 to B3:

[0139] Step B1: Determine the tire friction force of the tires of the vehicle based on the front axle load.

[0140] Exemplarily, the friction parameters and the front axle load may be processed to obtain the tire friction; Exemplarily, the friction parameters are related to the material, structure, roughness, and tilt angle of the surface supporting the vehicle.

[0141] Exemplarily, the friction force parameter and the front axle load may be cross-producted to obtain the tire friction force, and the tire friction force at this time may characterize the degree of resistance to the return operation of the steering system caused by the friction force generated by the front axle load.

[0142] Step B2: Process the tire contact patch width and the tire contact patch length to obtain tire contact patch parameters.

[0143] Exemplarily, the processor of the electronic device may process the tire contact patch width and the tire contact patch length to obtain tire footprint parameters.

[0144] Exemplarily, the tire footprint parameters may include the tire contact area; Exemplarily, the tire footprint parameters may include the effective area of ​​the tire contact area; Exemplarily, the tire footprint parameters may be closely related to at least one of the tire structure, surface characteristics, tire pressure, vehicle load and tire weight.

[0145] Exemplarily, the tire footprint parameters may include a median of a tire contact patch width and a tire contact patch length.

[0146] Step B3: Process the tire friction force and tire footprint parameters to obtain the steering friction torque.

[0147] Exemplarily, the processor of the electronic device may process the tire friction and tire footprint parameters to obtain the steering friction torque.

[0148] Exemplarily, the tire contact parameters may be fine-tuned based on the front axle load, and the steering friction torque may be determined according to the fine-tuned tire contact parameters and the front axle load.

[0149] Exemplarily, the tire friction force and the tire footprint parameter may be cross-producted to obtain the steering friction torque.

[0150] For example, the steering friction torque T can be determined by formula (8): F :

[0151]

[0152] In formula (8), G is the front axle load of the vehicle, and its unit is Newton (N), μ is the friction coefficient of the supporting surface of the vehicle, which is generally taken as 0.78, B and L are the tire contact patch width and tire contact patch length, respectively, and their units are both meters; G×μ is the tire friction force, and is the tire footprint parameter.

[0153] From the above, it can be seen that in the method for determining the rack force of a vehicle provided in an embodiment of the present invention, the tire contact parameters include the tire contact width and the tire contact footprint length. After obtaining the friction parameters, the friction parameters and the front axle load can be processed to obtain the tire friction, and the tire contact footprint width and the tire contact footprint length can be processed to obtain the tire footprint parameters, and then the tire footprint parameters and the tire friction can be processed to obtain the steering friction torque.

[0154] Therefore, in the method for determining the rack force of a vehicle provided in an embodiment of the present invention, in the process of obtaining the steering friction torque, four factors, namely, friction force parameters, front axle load, tire contact patch width and tire contact patch length, are fully considered, so that the friction torque includes various load states of the vehicle and the influence of various support surfaces on the steering friction torque, so that the steering friction torque can fully and comprehensively reflect the load state of the vehicle and the changing state of the support surface during the driving of the vehicle, thereby improving the accuracy of the steering friction torque.

[0155] Figure 3Another flow chart of a method for determining a rack force of a vehicle provided by an embodiment of the present invention is as follows: Figure 3 As shown, the method may include steps 301 to 306:

[0156] Step 301, start.

[0157] Exemplarily, the processor of the electronic device may determine parameters such as the type of vehicle, the application scenario, the type of the vehicle steering system, and the type of tires of the vehicle in this step.

[0158] Step 302: Determine the vehicle front axle load, maximum inner wheel turning angle, effective steering arm, front wheel kingpin inclination angle, kingpin offset, tire pressure, tire diameter, tire contact patch length, and tire contact patch width.

[0159] Exemplarily, the processor of the electronic device can determine parameters such as vehicle front axle load, maximum inner wheel turning angle, effective steering arm, front wheel kingpin inclination angle, kingpin offset, tire pressure, tire diameter, tire contact patch length and tire contact patch width.

[0160] Exemplarily, the effective steering lever arm may be the effective value of the steering lever arm in the aforementioned embodiment.

[0161] Step 303: Obtain gravity self-aligning torque.

[0162] Exemplarily, a processor of the electronic device may obtain the gravity-correcting torque.

[0163] For example, the front axle load, tire diameter, kingpin parameter, and inner wheel turning angle can be comprehensively processed by formula (3) to obtain the gravity self-aligning torque.

[0164] Step 304: Obtain steering friction torque.

[0165] Exemplarily, a processor of the electronic device may obtain the steering friction torque.

[0166] For example, the vehicle front axle load, the friction coefficient, the tire contact patch width, and the tire contact patch length can be calculated using formula (8) to obtain the steering friction torque.

[0167] Step 305: Determine the maximum rack force of the steering system according to the gravity self-aligning torque, the steering friction torque, and the effective steering arm.

[0168] Exemplarily, the processor of the electronic device may determine the maximum rack force of the steering system according to the gravity return torque, the steering friction torque, and the effective steering lever arm.

[0169] For example, the maximum rack force of the steering system can be determined by using formula (1) for the gravity self-aligning torque, the steering friction torque and the effective steering arm.

[0170] Step 306, end.

[0171] Exemplarily, the processor of the electronic device may obtain and output the maximum rack force of the steering system.

[0172] Figure 4 A schematic diagram of the structure of determining the rack force of a vehicle provided by an embodiment of the present invention. Figure 4 As shown, the structure may include: a gravity self-aligning torque obtaining unit 401 , a parameter determining unit 402 , a friction torque obtaining unit 403 and a maximum rack force determining unit 404 .

[0173] For example, the parameter determination unit 402 may determine parameters such as vehicle front axle load, maximum inner wheel turning angle, effective steering arm, front wheel kingpin inclination angle, kingpin offset, tire pressure, tire diameter, and tire contact patch width.

[0174] Among them, the parameter determination unit 402 includes an effective steering lever arm calculation unit 4021 and a tire contact patch length calculation unit 4022; exemplarily, the effective steering lever arm calculation unit 4021 can calculate the left extreme steering lever arm for left turn and the right extreme steering lever arm for right turn by formula (2), so as to obtain the effective steering lever arm; exemplarily, the tire contact patch length calculation unit 4022 can calculate the tire diameter and the tire radial deformation by formula (4), so as to obtain the tire contact patch length.

[0175] Exemplarily, the gravity-righting moment obtaining unit 401 can perform comprehensive processing on the front axle load, tire diameter, kingpin parameter, and inner wheel turning angle through equation (3) to obtain the gravity-righting moment.

[0176] Exemplarily, the friction torque obtaining unit 403 can calculate the vehicle front axle load, the friction coefficient, the tire contact patch width, and the tire contact patch length through equation (8), thereby obtaining the steering friction torque.

[0177] Exemplarily, the maximum rack force determination unit 404 can determine the maximum rack force of the steering system by using equation (1) to calculate the gravity self-aligning torque, the steering friction torque, and the effective steering arm.

[0178] In the related art, the rack force of the steering system is usually calculated by equation (9)-equation (10):

[0179]

[0180]

[0181] Among them, G t is the vertical load acting on a tire, its unit is Newton (N), μ is the friction coefficient between the tire and the surface supporting the tire, p is the tire pressure, its unit is Pa, T is the in-situ steering resistance torque, its unit is Nm, F R is the maximum rack force of the steering system, in Newton (N), L E is the effective steering arm, in meters.

[0182] From the above, it can be seen that in the relevant technology, the maximum rack force of the steering system is determined based on four factors: the vertical load of the tire, the friction coefficient, the tire pressure, and the effective steering arm. However, in actual applications, the number and types of factors that affect and determine the maximum rack force of the steering system far exceed the above four factors. Therefore, the accuracy of the maximum rack force of the steering system calculated by the above method cannot meet actual needs.

[0183] In the rack force determination method for a vehicle provided in an embodiment of the present invention, the rack force of the steering system is determined by a series of parameters such as the vehicle front axle load, the maximum inner wheel turning angle, the effective steering lever arm, the front wheel kingpin inclination angle, the kingpin offset, the tire pressure, the friction coefficient, the tire diameter, the tire contact patch width and the tire contact patch length, and the above parameters include effective parameters that can directly or indirectly affect the rack force of the steering system. That is to say, in the implementation process of the rack force determination method for a vehicle provided in an embodiment of the present invention, multiple parameters that have an impact on the rack force of the steering system are fully covered, thereby greatly improving the accuracy of the rack force.

[0184] Table 1

[0185]

[0186] Table 1 is the accuracy comparison data between the rack force determined by the solution provided by the related technology provided by the embodiment of the present invention and the rack force determined by the rack force determination method provided by the embodiment of the present invention.

[0187] Table 1 includes eight columns of data, including vehicle model, tire model, front axle load, measured maximum steering rack force, first rack force, first error, second rack force, and second error; wherein the unit of the front axle load is kilogram (Kg), the first rack force is the maximum rack force calculated by the rack force determination method provided by the embodiment of the present invention, in Newton (N), and the first error is the error of the first rack force; the second rack force is the maximum rack force determined by formula (9)-formula (10) provided in the relevant technology, in Newton (N), and the second error is the error of the second rack force. The first error and the second error are expressed in percentage.

[0188] In Table 1, the vehicle models may include C1 and S1. When the vehicle model is C1, the tire model is 215 / 50R17, and the front axle loads are 978, 1000, and 1024, respectively, the measured maximum rack forces are 7920, 8018, and 8343, respectively, the first rack forces are 7509.4, 7705.7, and 7921.0, respectively, and the first errors are 5.1843%, 3.895%, and 5.0581; and the second rack forces are 3920.9, 4053.9, and 4200.7, respectively, and the second errors are 50.4949%, 49.44%, and 5.0663%, respectively. 49.65%; when the vehicle model is S1, the tire model is 225 / 60R17, and the front axle loads are 973, 1027, and 1061 respectively, the measured maximum rack forces are 7176, 7491, and 7704 respectively; the first rack forces are 6937.5, 7389.8, and 7677.3 respectively, and the first errors are 3.3236%, 1.315%, and 0.3466% respectively; and the second rack forces are 3675.3, 3985.5, and 4185.0 respectively, and the second errors are 48.7834%, 49.7962%, and 45.6776% respectively.

[0189] According to the statistical results of the data in Table 1, no matter how the vehicle model, tire model and front axle load change, the error between the first rack force determined by the rack force determination method provided by the embodiment of the present invention and the measured maximum rack force is smaller than the error between the second rack force determined by the solution provided by the related art and the measured maximum rack force.

[0190] Among them, the first error can be the absolute value of the difference between the first rack force and the measured maximum steering rack force, and the ratio to the measured maximum steering rack force; the second error can be the absolute value of the difference between the second rack force and the measured maximum steering rack force, and the ratio to the measured maximum steering rack force.

[0191] From the above, it can be seen that the method for determining the rack force of a vehicle provided by the embodiment of the present invention fully covers multiple and various parameters that have an impact on the rack force during the rack force determination process, thereby greatly improving the accuracy of the rack force.

[0192] Based on the above embodiments, the present invention further provides a rack force determination device for a vehicle. Figure 5 A schematic diagram of the structure of a rack force determination device 5 for a vehicle provided in an embodiment of the present invention is shown in FIG. Figure 5 As shown, the device may include an acquisition module 501 and a determination module 502, wherein:

[0193] An acquisition module 501 is used to obtain a steering arm of a steering system of a vehicle, a steering friction torque of the steering system, and a gravity return torque;

[0194] The determination module 502 is used to determine the rack force based on the steering arm, the steering friction torque and the gravity return torque.

[0195] In some embodiments, the determination module 502 is used to collect statistics on the gravity self-aligning torque and the steering friction torque to obtain torque statistics results; and process the torque statistics results and the steering lever arm to determine the rack force.

[0196] In some embodiments, the determination module 502 is used to determine the steering arm based on a first parameter and a second parameter; wherein the first parameter includes a distance parameter between the left steering rod axis and the kingpin axis; and the second parameter includes a distance parameter between the right steering rod axis and the kingpin axis.

[0197] In some embodiments, the determination module 502 is used to perform a cross product calculation on the first parameter and the second parameter to obtain a third parameter; perform a sum calculation on the first parameter and the second parameter to obtain a fourth parameter; and process the third parameter and the fourth parameter to determine the steering arm.

[0198] In some embodiments, the acquisition module 501 is used to obtain the front axle load, tire diameter, kingpin parameters and inner wheel turning angle of the vehicle; the front axle load, tire diameter, kingpin parameters and inner wheel turning angle are processed to obtain the gravity self-aligning torque.

[0199] In some embodiments, the acquisition module 501 is used to obtain the front axle load and tire contact parameters of the vehicle;

[0200] The determination module 502 is used to determine the steering friction torque based on the front axle load and the tire contact parameters.

[0201] In some embodiments, the tire contact patch parameters include a tire contact patch width and a tire contact patch length;

[0202] The determination module 502 is used to determine the tire friction force of the tire of the vehicle based on the front axle load; process the tire contact patch width and the tire contact patch length to obtain tire footprint parameters; and process the tire friction force and the tire footprint parameters to determine the steering friction torque.

[0203] The rack force determination device 5 of the vehicle provided in the embodiment of the present invention, the gravity restoring torque and the steering friction torque can comprehensively reflect the resistance state that the steering system is borne during the steering operation, and the steering lever arm can characterize the actual steering state of the steering system. That is to say, the steering lever arm, steering friction torque and gravity restoring torque of the steering system are directly related to each steering operation of the steering system of the vehicle. Then, the rack force of the steering system determined based on the steering lever arm, steering friction torque and gravity restoring torque of the steering system must be consistent with the actual steering state and steering performance of the steering system, thereby improving the accuracy of the rack force of the steering system.

[0204] Based on the above embodiments, the present invention further provides a rack force determination device 6 for a vehicle. Figure 6 A schematic diagram of the structure of a rack force determination device 6 for a vehicle provided in an embodiment of the present invention is shown in FIG. Figure 6 As shown, the device may include: Figure 6 As shown, the device includes a processor 601, a memory 602, a communication interface 603 and a communication bus 604; the processor 601, the memory 602 and the communication interface 603 communicate with each other through the communication bus 604; the memory 602 is used to store at least one executable instruction 605; the executable instruction 605 enables the processor 601 to execute the rack force determination method of the vehicle as described in any of the above.

[0205] Exemplarily, the executable instructions 605 may include program codes. Exemplarily, the program codes may include computer executable instructions.

[0206] Exemplarily, the processor 601 may be at least one of an ASIC, a DSP, a DSPD, a PLD, an FPGA, a CPU, a controller, a microcontroller, and a microprocessor; exemplary, the processor 601 may include an integrated circuit.

[0207] Exemplarily, the rack force determination device 6 of the vehicle may include one or more processors 601; exemplary, when the number of processors 601 is multiple, the types of the multiple processors 601 may be the same, such as all being CPUs; exemplary, when the number of processors 601 is multiple, the types of the multiple processors 601 may be different, such as the multiple processors 601 may include at least one CPU and at least one ASIC.

[0208] Exemplarily, the memory 602 can be used to store executable instructions 605; exemplary, the memory 602 can be a volatile memory (volatile memory), such as a random access memory (Random Access Memory, RAM); or a non-volatile memory (non-volatile memory), such as a read-only memory (Read-Only Memory, ROM), a flash memory (flash memory), a hard disk drive (Hard Disk Drive, HDD) or a solid state drive (SSD); or a combination of the above types of memory, and provide instructions and data to the processor 601.

[0209] Exemplarily, the executable instruction 605 may be called by the processor 601 to enable the rack force determination device 6 of the vehicle to execute any of the rack force determination methods for the vehicle as described above.

[0210] Exemplarily, the acquisition module 501 and the determination module 502 in the aforementioned embodiment may be implemented by the processor 601 .

[0211] Based on the aforementioned embodiments, an embodiment of the present invention further provides a computer-readable storage medium, in which at least one executable instruction is stored, and the executable instruction enables a processor to execute any of the above-mentioned methods for determining the rack force of a vehicle.

[0212] The above description of various embodiments tends to emphasize the differences between the various embodiments. The same or similar aspects can be referenced to each other, and for the sake of brevity, they will not be repeated herein.

[0213] The methods disclosed in the various method embodiments provided by the present invention can be arbitrarily combined without conflict to obtain new method embodiments.

[0214] The features disclosed in the various product embodiments provided by the present invention can be arbitrarily combined without conflict to obtain new product embodiments.

[0215] The features disclosed in the various method or device embodiments provided by the present invention can be arbitrarily combined without conflict to obtain new method embodiments or device embodiments.

[0216] It should be noted that the above-mentioned computer-readable storage medium can be a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), a magnetic random access memory (FRAM), a flash memory (Flash Memory), a magnetic surface memory, an optical disc, or a compact disc read-only memory (CD-ROM) and other memories; it can also be various electronic devices including one or any combination of the above-mentioned memories, such as mobile phones, computers, tablet devices, personal digital assistants, etc.

[0217] It should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the existence of other identical elements in the process, method, article or device including the element.

[0218] The serial numbers of the above embodiments of the present invention are only for description and do not represent the advantages or disadvantages of the embodiments.

[0219] Through the description of the above implementation methods, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be implemented by means of software plus necessary general hardware nodes, and of course can also be implemented by hardware, but in many cases the former is a better implementation method. Based on such an understanding, the technical solution of the present invention is essentially or the part that contributes to the prior art can be embodied in the form of a software product, which is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk), including a number of instructions for a terminal device (which can be a mobile phone, computer, server, air conditioner, or network device, etc.) to execute the methods described in each embodiment of the present invention.

[0220] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0221] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0222] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0223] The above are only preferred embodiments of the present invention, and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A method for determining rack force of a vehicle, characterized in that: The method comprises: Obtaining a steering arm of a steering system of the vehicle; Obtaining a steering friction torque of the steering system; Obtaining the gravity return torque of the steering system; The gravity self-aligning torque and the steering friction torque are counted to obtain torque statistics results; the torque statistics results and the steering arm are processed to determine the rack force; The statistical analysis of the gravity self-aligning torque and the steering friction torque to obtain the torque statistical results includes: Analyzing factors of the steering friction torque whose influence on the gravity return torque is greater than or equal to a preset influence threshold, and performing statistics on the gravity return torque and the steering friction torque based on the factors, and determining the statistical results as the torque statistical results; or performing statistical average processing on the gravity return torque and the steering friction torque, and determining the statistical average processing result as the torque statistical result; The processing of the torque statistics result and the steering arm to determine the rack force includes: The F R is the rack force, the T B is the gravity self-aligning moment, and T F is the steering friction torque, the T B +T F is the moment statistics result, the L E is the steering arm; Wherein, obtaining the steering arm of the steering system of the vehicle includes: The L E is the steering arm, and L L is the first parameter, the L R As the second parameter, the 2×L L ×L R As the third parameter, the L L +L R is the fourth parameter; Wherein, the first parameter includes the distance between the left steering tie rod axis and the kingpin axis; The second parameter includes the distance between the right steering tie rod axis and the kingpin axis.

2. The method according to claim 1, characterized in that The obtaining of the gravity return torque of the steering system comprises: The T B is the gravity self-aligning torque, G is the front axle load of the vehicle, D is the tire diameter, s is the kingpin inclination angle, Dy is the kingpin offset distance, and θ is the maximum inner wheel turning angle.

3. The method according to claim 1, characterized in that The obtaining of the steering friction torque of the steering system comprises: Obtaining the front axle load and tire contact parameters of the vehicle; The steering friction torque is determined based on the front axle load and the tire contact contact parameter.

4. The method according to claim 3, characterized in that The tire contact parameters include a tire contact patch width and a tire contact patch length; and determining the steering friction torque based on the front axle load and the tire contact patch parameters includes: The T F is the steering friction torque, G is the front axle load of the vehicle, μ is the friction coefficient of the supporting surface of the vehicle, B is the tire contact patch width, L is the tire contact patch length, G×μ is the tire friction force, is the tire footprint parameter.

5. A rack force determination device for a vehicle, the device being applied to the rack force determination method for a vehicle as claimed in any one of claims 1 to 4.

6. A rack force determination device for a vehicle, characterized in that: The device includes a processor, a memory, a communication interface and a communication bus; the processor, the memory and the communication interface communicate with each other through the communication bus; The memory is used to store at least one executable instruction; the executable instruction enables the processor to execute the rack force determination method for a vehicle as described in any one of claims 1 to 4.

7. A computer-readable storage medium, characterized in that: The storage medium stores at least one executable instruction; the executable instruction enables the processor to execute the rack force determination method for a vehicle as described in any one of claims 1 to 4.

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