Automobile steering fluctuation rate calculation method and optimization method

Abstract

The embodiment of the invention provides an automobile steering fluctuation rate calculation method and optimization method, and the method comprises the steps: carrying out the modeling of each part of a steering column under a whole vehicle coordinate system in simulation software, and obtaining a model of each part; then assembling and constraining each part model by using positioning data of a steering system of a real vehicle to obtain a steering model; giving a design angular velocity parameter degree for an input shaft of the steering model to enable the input shaft to rotate for set time; the angular velocity of the output shaft at each moment within the set time is obtained, then the angular velocity fluctuation ratio is obtained by combining the designed angular velocity parameter degree, and the angular velocity fluctuation ratio can be obtained by only paying attention to the angular velocity calculation in the above steps for the steering system with four or more sections of steering columns. The increased step of obtaining the included angle and the phase angle between different steering columns due to the influence of the section number of the steering columns is avoided, the influence of the section number of the steering columns is avoided, and the optimization efficiency of the steering system is improved through the rapidly obtained angular velocity fluctuation rate.

Description

Technical Field

[0001] The present application relates to the field of automobile analysis, and in particular to a method for calculating and optimizing automobile steering fluctuation rate. Background Art

[0002] Currently, steering force is a key metric for evaluating vehicle steering performance. The magnitude of steering force and torque fluctuations directly impact driving comfort. As demand for driving comfort increases, so too does steering requirements. The mainstream steering systems in passenger cars now feature EHPS (Electronic Hydrostatic Power Steering) or EPS (Electric Power Steering), which improve steering comfort and offer significant energy savings and environmental benefits. However, both EHPS and EPS systems rely on the steering transmission mechanism—the steering column. The quality of the steering column layout directly impacts steering force transmission. Improper layout compromises steering comfort and negatively impacts the service life of components like the steering pump and motor.

[0003] In related technologies, with the development of automobile industry analysis, forward design is becoming more and more common, and the application of automobile CAE (computer-aided engineering in engineering design) and related design calculations is becoming more and more extensive; the existing method for calculating automobile steering torque fluctuation is to draw a list of the hard points of the steering transmission system in the drawing software, and then substitute them into the relevant formulas for repeated calculation until the requirements are met. For example, China's application CN115730173A discloses a method for calculating automobile steering torque fluctuation, which uses an EXCEL table to calculate the steering fluctuation rate. However, the EXCEL table calculation is usually only applicable to three-section steering columns. It is difficult to simulate the spatial phase angle problem of steering columns with four or more sections, and the calculation steps and amount of calculation are large.

[0004] In other related technologies, the traditional three-section steering column includes an input shaft, an intermediate shaft, and an output shaft. The two ends of the intermediate shaft are connected to the input shaft and the intermediate shaft through universal joints. During the optimization process, it is necessary to obtain the volatility of the steering system to guide the optimization. Generally, the volatility is obtained through angular velocity volatility or torque volatility; however, whether it is angular velocity volatility or torque volatility, it needs to be calculated using formulas based on relevant parameters such as input angle, output angle, phase angle, angle between the input shaft and the intermediate shaft, and angle between the intermediate shaft and the output shaft; when it comes to the optimization design of four or more sections of steering columns, there are many parameters, which makes the optimization process long and cumbersome. It is necessary to design a simpler and faster volatility acquisition method and steering column optimization method. Summary of the Invention

[0005] The embodiments of the present application provide a method for calculating and optimizing the steering fluctuation rate of an automobile, so as to solve the problem of the cumbersome calculation process when optimizing the design of a steering column with four or more sections by using a traditional three-section steering column in the related art, which requires obtaining relevant parameters such as the input angle, output angle, phase angle, the angle between the input shaft and the intermediate shaft, and the angle between the intermediate shaft and the output shaft to calculate the fluctuation rate.

[0006] In a first aspect, a method for calculating automobile steering fluctuation rate is provided, which includes:

[0007] Obtain the coordinates of multiple hard points of the steering system of the actual vehicle in the vehicle coordinate system to obtain positioning data; the hard points include the center point of the steering wheel, the center points of each universal joint of multiple steering columns, and the meshing point of the steering gear rack;

[0008] Modeling the various components of the steering column in the vehicle coordinate system in the simulation software to obtain models of the various components; assembling and constraining the various component models using the positioning data to obtain a steering model;

[0009] The input shaft of the steering model is given a design angular velocity parameter to make it rotate for a set time; the angular velocity of the output shaft at each moment within the set time is obtained, and then the angular velocity fluctuation rate is obtained by combining the design angular velocity parameter.

[0010] In some embodiments, modeling each component of the steering column in a vehicle coordinate system in simulation software to obtain each component model; assembling and constraining each component model using the positioning data to obtain a steering model specifically includes the following steps:

[0011] In the vehicle coordinate system of CATIA software, the model of each component of the steering column is obtained according to the material and size information of each component;

[0012] In the vehicle coordinate system of CATIA software, hard points are created according to the positioning data, and then connected in sequence with straight lines to form an auxiliary positioning model;

[0013] Using the DMU motion mechanism module in CATIA software, with the auxiliary positioning model as the benchmark and combined with the assembly tolerance, the component models and hard points are assembled and constrained according to the actual vehicle status to obtain the steering model.

[0014] In some embodiments, the speed and acceleration function module in CATIA software is used to set a design angular velocity parameter for the input shaft of the steering model so that it rotates for a set time;

[0015] Use the velocity and acceleration function module in CATIA software to activate the sensor module to read the angular velocity of the output shaft at each moment within the set time;

[0016] The velocity and acceleration function module in CATIA software is used to combine the angular velocity of the output shaft at each moment within the set time with the designed angular velocity parameters to obtain the angular velocity fluctuation rate.

[0017] In some embodiments, the design angular velocity parameter is a constant angular velocity;

[0018] The angular velocity fluctuation rate is obtained by combining the angular velocity of the output shaft at each moment within the set time with the constant angular velocity, which specifically includes the following steps:

[0019] Filter out the maximum angular velocity and the minimum angular velocity from the angular velocity of the output shaft at each moment within the set time;

[0020] According to the maximum angular velocity, the minimum angular velocity and the constant angular velocity, the angular velocity fluctuation rate is obtained by combining the first calculation formula;

[0021] The first calculation formula is:

[0022] In some embodiments, the designed angular velocity parameter is a change in angular velocity from a first angular velocity to a second angular velocity within a set time;

[0023] The angular velocity fluctuation rate is obtained by combining the angular velocity of the output shaft at each moment within the set time with the designed angular velocity parameters, specifically including the following steps:

[0024] Processing the designed angular velocity parameters according to the time axis of the set time to obtain a first curve of time and angular velocity;

[0025] The angular velocity of the output shaft at each moment within the set time is processed according to the time axis of the set time to obtain a second curve of time and angular velocity;

[0026] Calculate the overlap between the first curve and the second curve, and then use the following second calculation formula to obtain the angular velocity fluctuation rate;

[0027] The second calculation formula is: angular velocity fluctuation rate = 1 - coincidence rate.

[0028] In a second aspect, a method for optimizing vehicle steering fluctuation rate is provided, which comprises the following steps:

[0029] According to the calculation method of automobile steering fluctuation rate, the angular velocity fluctuation rate of the steering system to be optimized is simulated and calculated;

[0030] Determine whether the angular velocity fluctuation rate is greater than the target threshold;

[0031] If so, the yoke phase angle of the intermediate shaft connected to the output shaft in the steering model is adjusted; after the adjustment, the iteration step is entered;

[0032] If not, the steering system needs to be optimized to meet the requirements.

[0033] In some embodiments, the iterative step specifically includes:

[0034] The angular velocity fluctuation rate of the adjusted steering model is obtained according to the automobile steering fluctuation rate calculation method;

[0035] Determine whether the angular velocity fluctuation rate of the adjusted steering model is greater than a target threshold;

[0036] If yes, then adjust the yoke phase angle of the intermediate shaft connected to the output shaft in the steering model again, and then return to the step of obtaining the angular velocity fluctuation rate of the adjusted steering model according to the automobile steering fluctuation rate calculation method;

[0037] If not, the iteration step ends.

[0038] In some embodiments, the iterating step further comprises:

[0039] Record the number of times the yoke phase angle of the intermediate shaft connected to the output shaft in the steering model is adjusted;

[0040] When the number of adjustments is greater than the design number and the angular velocity fluctuation rate of the adjusted steering model is still greater than the target threshold, the adjustment method of the yoke phase angle of the intermediate shaft connected to the output shaft in the steering model is changed to adjusting the two hard point coordinates of the intermediate shaft connected to the output shaft in the steering model.

[0041] In some embodiments, after the step of simulating and calculating the angular velocity fluctuation rate of the steering model according to the automobile steering fluctuation rate calculation method, and before the step of determining whether the angular velocity fluctuation rate is greater than a target threshold, the following steps are further included:

[0042] The angular velocity fluctuation rate of the steering model calculated by simulation is multiplied by the calibration simulation parameter to obtain the compensated angular velocity fluctuation rate;

[0043] The angular velocity fluctuation rate in the step of determining whether the angular velocity fluctuation rate is greater than the target threshold value is replaced with the angular velocity fluctuation rate after compensation.

[0044] In some embodiments, obtaining calibration simulation parameters includes the following steps:

[0045] The actual vehicle with the steering system to be optimized is subjected to actual bench testing. The input shaft of the actual vehicle is given a designed angular velocity parameter and rotated for a set time. The angular velocity of the output shaft of the actual vehicle at each moment in the set time is obtained, and then the actual angular velocity fluctuation rate is obtained by combining the designed angular velocity parameter.

[0046] The angular velocity fluctuation rate of the steering model obtained by simulation is divided by the actual angular velocity fluctuation rate to obtain the calibration simulation parameters.

[0047] The beneficial effects of the technical solution provided by this application include:

[0048] An embodiment of the present application provides a method for calculating and optimizing the steering fluctuation rate of an automobile. The components of the steering column are modeled in the whole vehicle coordinate system in the simulation software to obtain models of each component. The positioning data of the steering system of the actual vehicle is then used to assemble and constrain the component models to obtain a steering model. The input shaft of the steering model is then given a design angular velocity parameter to rotate it for a set time. The angular velocity of the output shaft at each moment in the set time is obtained, and then the angular velocity fluctuation rate is obtained in combination with the design angular velocity parameter. For a steering system with four or more steering columns, the above steps only require calculating the angular velocity to obtain the angular velocity fluctuation rate, avoiding the additional steps of obtaining the angle and phase angle between different steering columns due to the influence of the number of steering column sections. The angular velocity fluctuation rate is not affected by the number of steering column sections, and the rapidly obtained angular velocity fluctuation rate accelerates the optimization efficiency of the steering system. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0050] Figure 1 A diagram showing a steering model in CATIA software provided in an embodiment of the present application;

[0051] Figure 2 A schematic diagram of the phase angle in the CATIA software provided in an embodiment of the present application;

[0052] Figure 3 A flow chart of a method for calculating vehicle steering volatility provided in an embodiment of the present application. DETAILED DESCRIPTION

[0053] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0054] The technical terms in this application are explained as follows:

[0055] Angular velocity fluctuation rate, applicable scenarios:

[0056] Dynamic response analysis: If the focus is on the dynamic response characteristics of the steering system (such as steering sensitivity, vibration, or delay), the angular velocity fluctuation rate more directly reflects the transient characteristics of the steering input.

[0057] Electric Power Steering (EPS): The EPS system relies on a motor to control angular velocity. The angular velocity fluctuation rate can help optimize motor response and suppress high-frequency vibrations.

[0058] Comfort-oriented design: In passenger car design, the smoothness of angular velocity directly affects driving comfort, such as the "silky feel" when steering.

[0059] Angular velocity directly reflects the speed of steering movements, making it useful for evaluating the steering system's followability and smoothness. Angular velocity can be directly measured using a speed sensor or encoder, which is inexpensive and easy to obtain. However, it cannot directly reflect the impact of external loads (such as road impact and tire friction) on the steering system.

[0060] Torque fluctuation rate, applicable scenarios:

[0061] Optimizing driver feel: If the design goal is to reduce steering wheel "hitting" or sudden torque changes (such as feedback from bumpy roads), torque fluctuation rate is more critical.

[0062] Commercial vehicle or performance vehicle design: In scenarios where precise control of steering feedback torque is required (such as track driving or heavy-loaded vehicles), torque fluctuation rate can better reflect system stability.

[0063] Hydraulic Power Steering (HPS): Pressure fluctuations in the hydraulic system directly affect torque and require intensive monitoring.

[0064] Torque fluctuation is directly related to changes in steering system load (such as road disturbances and tire lateral forces), and is more closely aligned with the driver's perceived force. Sudden changes in torque can indicate mechanical component failure (such as seizure or breakage), making it suitable for durability testing. However, torque fluctuation can lag behind angular velocity changes, making it difficult to use solely for dynamic response optimization.

[0065] This application's problem arises from optimizing the steering system of a vehicle equipped with a four-stage steering column to improve its dynamic response and driving comfort. A four-stage steering column is a traditional three-stage column with an additional intermediate shaft. Therefore, the challenge is how to quickly and effectively implement this optimization solution using simulation technology.

[0066] At present, the traditional three-section steering column needs to obtain relevant parameters such as input angle, output angle, phase angle, angle between the input shaft and the intermediate shaft, and angle between the intermediate shaft and the output shaft to calculate the fluctuation rate. However, when optimizing the design of steering columns with four sections or more, the parameters that need to be obtained increase with the number of sections of the steering column, resulting in a cumbersome calculation process. In addition, as the number of intermediate shafts increases, the number of steering knuckles also increases. At this time, it is unknown which intermediate shaft should be mainly adjusted, or whether all of them should be adjusted. Therefore, an efficient optimization design method is needed.

[0067] In summary, a calculation method and optimization method for automobile steering fluctuation rate are proposed to cope with the design scenarios of steering columns with four or more sections.

[0068] In a first aspect, a method for calculating automobile steering volatility comprises the following steps:

[0069] Step 100: Obtain the coordinates of multiple hard points of the steering system of the actual vehicle in the vehicle coordinate system to obtain positioning data; the hard points include the center point of the steering wheel, the center points of the universal joints of multiple steering columns, and the meshing point of the steering gear rack; the coordinates of these hard points are obtained from actual measurements. This step is a common technology and will not be described in detail; the hard points A, B, C, D, E are as follows: Figure 1 As shown;

[0070] The hard point coordinates can be referred to the following table.

[0071] Hard Point X Y Z Steering wheel center point 628 -435 668 Upper universal joint center point 298 -435 448 Center point of the universal joint 208 -430 208 Lower universal joint center point 203 -433 88 Steering gear rack meshing point 185 -262 -202

[0072] Step 200: Model each component of the steering column in the vehicle coordinate system in the simulation software to obtain each component model; assemble and constrain each component model using the positioning data to obtain a steering model; the steering model can refer to Figure 1 The content shown.

[0073] Step 300: The input shaft of the steering model is given a designed angular velocity parameter to rotate for a set time; the angular velocity of the output shaft at each moment within the set time is obtained, and then the angular velocity fluctuation rate is obtained by combining the designed angular velocity parameter.

[0074] Since the various components of the steering column are modeled in the whole vehicle coordinate system in the simulation software, the models of each component are obtained; then the positioning data of the steering system of the actual vehicle are used to assemble and constrain the various component models to obtain the steering model; then the input shaft of the steering model is given a design angular velocity parameter to make it rotate for a set time; the angular velocity of the output shaft at each moment in the set time is obtained, and then the angular velocity fluctuation rate is obtained in combination with the design angular velocity parameter. The above steps only need to focus on calculating the angular velocity when targeting a steering system with four or more steering columns to obtain the angular velocity fluctuation rate, avoiding the additional steps of obtaining the angle and phase angle between different steering columns due to the influence of the number of steering column sections. It is not affected by the number of steering column sections, and the quickly obtained angular velocity fluctuation rate accelerates the optimization efficiency of the steering system.

[0075] It should be understood that this application is an optimization for the steering system of a real vehicle, and focuses more on the dynamic response characteristics of the steering system. The angular velocity directly reflects the speed of the steering action, which is convenient for evaluating the followability and smoothness of the steering system. Therefore, the angular velocity fluctuation rate is used as an optimization indicator for the steering system.

[0076] In some preferred embodiments, step 200 specifically includes the following steps:

[0077] In the vehicle coordinate system of CATIA software, the model of each component of the steering column is obtained according to the material and size information of each component;

[0078] In the vehicle coordinate system of CATIA software, hard points are created according to the positioning data, and then connected with straight lines in sequence to form an auxiliary positioning model;

[0079] Using the DMU kinematics module in CATIA software, with the auxiliary positioning model as the reference and assembly tolerances in mind, the component models and hard points are assembled and constrained according to the actual vehicle conditions to create a steering model. Constraints can be fixed by fixing the hard points and their connecting lines, using rotational constraints and hard point connecting line constraints on the steering axis, and using rotational constraints on the yoke and cross universal joint.

[0080] In this embodiment, the modeling and simulation of this application are all implemented through CATIA software. The models of each component are obtained by modeling according to the material and size information of each component of the steering column. The auxiliary positioning model is used as a reference and the assembly tolerance is combined to ensure the accuracy of the modeling, which is closer to the actual vehicle.

[0081] In some preferred embodiments, in step 300, the speed and acceleration function module in CATIA software is used to give a design angular velocity parameter to the input shaft of the steering model so that it rotates for a set time;

[0082] Use the velocity and acceleration function module in CATIA software to activate the sensor module to read the angular velocity of the output shaft at each moment within the set time.

[0083] The velocity and acceleration function module in CATIA software is used to combine the angular velocity of the output shaft at each moment within the set time with the designed angular velocity parameters to obtain the angular velocity fluctuation rate.

[0084] Furthermore, the design angular velocity parameters can be expressed in the following two forms:

[0085] Form 1: the design angular velocity parameter is a constant angular velocity;

[0086] The angular velocity fluctuation rate is obtained by combining the angular velocity of the output shaft at each moment within the set time with the constant angular velocity, which specifically includes the following steps:

[0087] Filter out the maximum angular velocity and the minimum angular velocity from the angular velocity of the output shaft at each moment within the set time;

[0088] According to the maximum angular velocity, the minimum angular velocity and the constant angular velocity, the angular velocity fluctuation rate is obtained by combining the first calculation formula;

[0089] The first calculation formula is:

[0090] Form 1 does not consider the fact that constant angular velocity input does not cover actual transient conditions (such as sharp turns or step inputs) and may miss dynamic response issues. Therefore, Form 2 is designed.

[0091] Form 2: The angular velocity parameter is designed to change from a first angular velocity to a second angular velocity within a set time;

[0092] The angular velocity fluctuation rate is obtained by combining the angular velocity of the output shaft at each moment within the set time with the designed angular velocity parameters, specifically including the following steps:

[0093] Processing the designed angular velocity parameters according to the time axis of the set time to obtain a first curve of time and angular velocity;

[0094] The angular velocity of the output shaft at each moment within the set time is processed according to the time axis of the set time to obtain a second curve of time and angular velocity;

[0095] Calculate the overlap between the first curve and the second curve, and then use the following second calculation formula to obtain the angular velocity fluctuation rate;

[0096] The second calculation formula is: angular velocity fluctuation rate = 1-coincidence rate.

[0097] The second form focuses on the degree of agreement between the first and second curves within a set time period to judge volatility.

[0098] In a second aspect, a method for optimizing vehicle steering fluctuation rate is provided, which comprises the following steps:

[0099] According to the above calculation method of automobile steering fluctuation rate, the angular velocity fluctuation rate of the steering system to be optimized is simulated and calculated;

[0100] Determine whether the angular velocity fluctuation rate is greater than the target threshold;

[0101] If so, the yoke phase angle of the intermediate shaft connected to the output shaft in the steering model is adjusted; after the adjustment, the iteration step is entered;

[0102] If not, the steering system needs to be optimized to meet the requirements.

[0103] The above steps follow the steering model used in the automotive steering volatility calculation method. Through this model, we can intuitively understand the rotation of the column and the impact of the hard point and phase angle on the volatility, which is consistent with the actual vehicle state. The hard point and phase angle can then be adjusted in the steering model to facilitate iterative optimization. In other words, after each adjustment of the hard point or phase angle, the angular velocity volatility can be quickly derived, and the effect of the adjustment can be evaluated. Ultimately, a satisfactory angular velocity volatility can be quickly obtained. Based on this angular velocity volatility, the corresponding hard point coordinates or phase angle can be determined, and the actual vehicle's steering system can then be adjusted based on the final hard point coordinates or phase angle.

[0104] It should be understood that during optimization, we adjust the hard point coordinates or phase angles, that is, how to find the hard point coordinates or phase angles that meet the requirements among uncertain hard point coordinates or phase angles.

[0105] In some preferred embodiments, the iterative step specifically includes:

[0106] According to the above automobile steering fluctuation rate calculation method, the angular velocity fluctuation rate of the adjusted steering model is obtained;

[0107] Determine whether the angular velocity fluctuation rate of the adjusted steering model is greater than a target threshold;

[0108] If yes, then adjust the yoke phase angle of the intermediate shaft connected to the output shaft in the steering model again, and then return to the step of obtaining the angular velocity fluctuation rate of the adjusted steering model according to the automobile steering fluctuation rate calculation method;

[0109] If not, the iteration step ends.

[0110] In this embodiment, the specific method of adjustment is defined, that is, directly adjusting the yoke phase angle of the intermediate shaft connected to the output shaft, and providing a specific adjustment object, so that the adjustment will not be made blindly. The consideration for such adjustment is that, usually in a real vehicle, due to the influence of assembly and vehicle space layout, the space where the other intermediate shafts are located is relatively small, which is inconvenient to adjust with the real vehicle. The method of this embodiment facilitates the real vehicle to be adjusted according to the simulation optimization results, and is not affected by the internal structure layout of the vehicle. The optimization scheme obtained by adjusting the lowest intermediate shaft is related to the real vehicle adjustment and is more in line with the actual scenario. In addition, the phase angle referred to in this application is the angle between the central axes of the two yokes of the intermediate shaft connected to the output shaft, refer to Figure 2 The content shown is the phase angle (φ is an arbitrary angle, the position shown is 90°).

[0111] Furthermore, when the yoke phase angle of the intermediate shaft connected to the output shaft is adjusted multiple times and the fluctuation rate is still not effectively reduced, the iterative steps further include:

[0112] Record the number of times the yoke phase angle of the intermediate shaft connected to the output shaft in the steering model is adjusted;

[0113] When the number of adjustments is greater than the design number and the angular velocity fluctuation rate of the adjusted steering model is still greater than the target threshold, the adjustment method of the yoke phase angle of the intermediate shaft connected to the output shaft in the steering model is changed to adjusting the two hard point coordinates of the intermediate shaft connected to the output shaft in the steering model.

[0114] Through the above adjustment and optimization method, the rotation of the steering column can be visually observed, and the influence of different hard points and phase angles on the fluctuation rate can be intuitively understood. This method is consistent with the actual vehicle state, and the optimization process is not affected by the number of steering column segments. There is no need to increase the number of steering column segments in the EXCEL table to increase the calculation amount.

[0115] In some preferred embodiments, after the step of simulating and calculating the angular velocity fluctuation rate of the steering model according to the automobile steering fluctuation rate calculation method, and before the step of determining whether the angular velocity fluctuation rate is greater than a target threshold, the following steps are further included:

[0116] The angular velocity fluctuation rate of the steering model calculated by simulation is multiplied by the calibration simulation parameter to obtain the compensated angular velocity fluctuation rate;

[0117] The angular velocity fluctuation rate in the step of determining whether the angular velocity fluctuation rate is greater than the target threshold value is replaced with the angular velocity fluctuation rate after compensation.

[0118] The process of obtaining the calibration simulation parameters includes the following steps:

[0119] The actual vehicle with the steering system to be optimized is subjected to actual bench testing. The input shaft of the actual vehicle is given a designed angular velocity parameter and rotated for a set time. The angular velocity of the output shaft of the actual vehicle at each moment in the set time is obtained, and then the actual angular velocity fluctuation rate is obtained by combining the designed angular velocity parameter.

[0120] The angular velocity fluctuation rate of the steering model obtained by simulation is divided by the actual angular velocity fluctuation rate to obtain the calibration simulation parameters.

[0121] Through the above methods, the data of the actual experiment are correlated and simulation verification is carried out in the early stage to improve the accuracy of the angular velocity fluctuation rate obtained by simulation, ensure the authenticity of the optimization and improve the engineering practicality of the results.

[0122] In the description of this application, it should be noted that the terms "upper" and "lower" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application. Unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be internal communication between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0123] It should be noted that, in this application, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising 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 "comprising a ..." does not exclude the presence of other identical elements in the process, method, article or device comprising the element.

[0124] The foregoing is merely a list of specific embodiments of the present application, intended to enable those skilled in the art to understand or implement the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application is not limited to the embodiments shown herein, but is intended to conform to the broadest scope consistent with the principles and novel features of the present application.

Claims

1. A method for calculating automobile steering fluctuation rate, characterized in that: It includes: Obtain the coordinates of multiple hard points of the steering system of the actual vehicle in the vehicle coordinate system to obtain positioning data; The hard points include the center point of the steering wheel, the center points of the universal joints of multiple steering columns, and the meshing point of the steering gear rack and pinion; Modeling the various components of the steering column in the vehicle coordinate system in the simulation software to obtain models of the various components; assembling and constraining the various component models using the positioning data to obtain a steering model; The input shaft of the steering model is given a design angular velocity parameter to make it rotate for a set time; Obtain the angular velocity of the output shaft at each moment within the set time, and then combine the designed angular velocity parameters to obtain the angular velocity fluctuation rate.

2. The method for calculating automobile steering fluctuation rate according to claim 1, wherein: Modeling the various components of the steering column in the vehicle coordinate system in the simulation software to obtain the component models; assembling and constraining the component models using the positioning data to obtain the steering model, specifically comprising the following steps: In the vehicle coordinate system of CATIA software, the model of each component of the steering column is obtained according to the material and size information of each component; In the vehicle coordinate system of CATIA software, hard points are created according to the positioning data, and then connected in sequence with straight lines to form an auxiliary positioning model; Using the DMU motion mechanism module in CATIA software, with the auxiliary positioning model as the benchmark and combined with the assembly tolerance, the component models and hard points are assembled and constrained according to the actual vehicle status to obtain the steering model.

3. The method for calculating automobile turning fluctuation rate according to claim 2, wherein: Using the speed and acceleration function module in CATIA software, the input shaft of the steering model is given a design angular velocity parameter to make it rotate for a set time. Use the velocity and acceleration function module in CATIA software to activate the sensor module to read the angular velocity of the output shaft at each moment within the set time; The velocity and acceleration function module in CATIA software is used to combine the angular velocity of the output shaft at each moment within the set time with the designed angular velocity parameters to obtain the angular velocity fluctuation rate.

4. The method for calculating automobile turning fluctuation rate according to claim 3, wherein: The designed angular velocity parameter is a constant angular velocity; The angular velocity fluctuation rate is obtained by combining the angular velocity of the output shaft at each moment within the set time with the constant angular velocity, which specifically includes the following steps: Filter out the maximum angular velocity and the minimum angular velocity from the angular velocity of the output shaft at each moment within the set time; According to the maximum angular velocity, the minimum angular velocity and the constant angular velocity, the angular velocity fluctuation rate is obtained by combining the first calculation formula; The first calculation formula is:

5. The method for calculating automobile steering fluctuation rate according to claim 3, wherein: The designed angular velocity parameter is that the angular velocity changes from a first angular velocity to a second angular velocity within a set time; The angular velocity fluctuation rate is obtained by combining the angular velocity of the output shaft at each moment within the set time with the designed angular velocity parameters, specifically including the following steps: Processing the designed angular velocity parameters according to the time axis of the set time to obtain a first curve of time and angular velocity; The angular velocity of the output shaft at each moment within the set time is processed according to the time axis of the set time to obtain a second curve of time and angular velocity; Calculate the overlap between the first curve and the second curve, and then use the following second calculation formula to obtain the angular velocity fluctuation rate; The second calculation formula is: angular velocity fluctuation rate = 1 - coincidence rate.

6. A method for optimizing automobile steering fluctuation rate, characterized in that: It includes the following steps: According to the automobile steering fluctuation rate calculation method as claimed in claim 1, the angular velocity fluctuation rate of the steering system to be optimized is simulated and calculated; Determine whether the angular velocity fluctuation rate is greater than the target threshold; If so, the yoke phase angle of the intermediate shaft connected to the output shaft in the steering model is adjusted; after the adjustment, the iteration step is entered; If not, the steering system needs to be optimized to meet the requirements.

7. The method for optimizing automobile steering fluctuation rate according to claim 6, characterized in that: The iterative steps specifically include: Obtaining the angular velocity fluctuation rate of the adjusted steering model according to the automobile steering fluctuation rate calculation method as claimed in claim 1; Determine whether the angular velocity fluctuation rate of the adjusted steering model is greater than a target threshold; If so, the yoke phase angle of the intermediate shaft connected to the output shaft in the steering model is adjusted again, and then the process returns to the step of obtaining the adjusted angular velocity fluctuation rate of the steering model according to the method for calculating the automobile steering fluctuation rate as claimed in claim 1 ; If not, the iteration step ends.

8. The method for optimizing automobile steering fluctuation rate according to claim 7, characterized in that: The iterative step further comprises: Record the number of times the yoke phase angle of the intermediate shaft connected to the output shaft in the steering model is adjusted; When the number of adjustments is greater than the design number and the angular velocity fluctuation rate of the adjusted steering model is still greater than the target threshold, the adjustment method of the yoke phase angle of the intermediate shaft connected to the output shaft in the steering model is changed to adjusting the two hard point coordinates of the intermediate shaft connected to the output shaft in the steering model.

9. The method for optimizing automobile steering fluctuation rate according to claim 6, wherein: After the step of simulating and calculating the angular velocity fluctuation rate of the steering model according to the automobile steering fluctuation rate calculation method as claimed in claim 1, and before the step of determining whether the angular velocity fluctuation rate is greater than a target threshold, the method further includes the following steps: The angular velocity fluctuation rate of the steering model calculated by simulation is multiplied by the calibration simulation parameter to obtain the compensated angular velocity fluctuation rate; The angular velocity fluctuation rate in the step of determining whether the angular velocity fluctuation rate is greater than the target threshold value is replaced with the angular velocity fluctuation rate after compensation.

10. The method for optimizing automobile steering fluctuation rate according to claim 9, wherein: Obtaining calibration simulation parameters includes the following steps: The actual vehicle with the steering system to be optimized is subjected to actual bench testing. The input shaft of the actual vehicle is given a designed angular velocity parameter and rotated for a set time. The angular velocity of the output shaft of the actual vehicle at each moment in the set time is obtained, and then the actual angular velocity fluctuation rate is obtained by combining the designed angular velocity parameter. The angular velocity fluctuation rate of the steering model obtained by simulation is divided by the actual angular velocity fluctuation rate to obtain the calibration simulation parameters.

Images