A parking load digitization method and system for a vehicle steering system

Abstract

The present invention discloses a method for digitizing parking loads of vehicle steering systems, comprising the following steps: 100: collecting steering rod force values ​​and steering wheel angle values ​​for various vehicle models during parking; 200: generating a steering rod force-steering wheel angle relationship curve; 300: based on the steering rod force-steering wheel angle relationship curve, plotting the maximum envelope of all steering rod force-steering wheel angle relationship curves; 400: setting a plurality of control points based on the maximum steering wheel angle and maximum rack force of the steering system of each vehicle model; 500: optimizing the abscissa and ordinate of each control point so that each control point continuously approaches the maximum envelope; 600: connecting the optimized control points to obtain a control line; 700: determining whether the control line completely covers the maximum envelope; if so, outputting the control line; if not, returning to step 400. Accordingly, the present invention also discloses a system for digitizing parking loads of vehicle steering systems.

Description

Technical Field

[0001] The present invention relates to a vehicle testing system and method, and in particular to a vehicle steering system testing method and system. Background Art

[0002] Currently, during the development or verification process of vehicle steering systems, whole-vehicle measurements are required to obtain system load conditions for defining design parameters or experimentally verifying load inputs.

[0003] However, in the early stages of vehicle development, there is often no matching prototype vehicle for vehicle load measurement, which prolongs the development cycle. In addition, full vehicle measurement also leads to high personnel and testing costs for vehicle development.

[0004] Based on this, in order to shorten the vehicle development cycle and reduce vehicle development costs, it is expected to obtain a digital method for the parking load of the vehicle steering system. Based on the analysis of historical measurement big data, the vehicle steering system load distribution can be normalized to the load automatically distributed related to the steering angle and the design rack force through the control of influencing factors, thereby solving the data source problem of the steering system load. Summary of the Invention

[0005] One objective of the present invention is to provide a method for digitizing vehicle steering system parking loads. Based on analysis of historical measurement data, this method automatically normalizes the steering system load distribution to a load distribution related to steering angle and design rack force using influencing factors, thereby resolving the data source issue for steering system loads. This method eliminates the need for full vehicle measurements to obtain design or test loads, significantly reducing steering system development cycles and testing costs.

[0006] In order to achieve the above object, the present invention proposes a method for digitizing parking load of a vehicle steering system, which comprises the following steps:

[0007] 100: Collect the steering rod force values ​​and the corresponding steering wheel angle values ​​of each vehicle model during the historical parking process;

[0008] 200: Generate a steering rod force-steering wheel angle relationship curve for each vehicle model;

[0009] 300: Based on the steering rod force-steering wheel angle relationship curves of various vehicle models, the maximum envelope of all steering rod force-steering wheel angle relationship curves is drawn;

[0010] 400: Based on the maximum steering wheel angle and maximum rack force of the steering system of each vehicle model, a plurality of control points are set, wherein the abscissa of each control point is the maximum steering wheel angle multiplied by a first percentile of the setting, and the ordinate of each control point is the maximum rack force multiplied by a second percentile of the setting; the control points are plotted based on the abscissa and ordinate of each control point;

[0011] 500: Optimizing the horizontal coordinate and the vertical coordinate of each control point so that each control point continuously approaches the maximum envelope;

[0012] 600: Connect the optimized control points to obtain a control line;

[0013] 700: Determine whether the control line completely covers the maximum envelope line. If yes, output the control line; if no, return to step 400.

[0014] Furthermore, in the vehicle steering system parking load digitization method described in the present invention, the steering rod force value includes a left steering rod force value and a right steering rod force value.

[0015] Furthermore, in the vehicle steering system parking load digitization method of the present invention, there are 15-20 groups of control points.

[0016] Another objective of the present invention is to provide a vehicle steering system parking load digitization system. Based on analysis of historical measurement data, this system automatically normalizes the vehicle steering system load distribution to a load distribution related to steering angle and design rack force using influencing factors, thereby resolving the data source issue for steering system loads. This system eliminates the need for full vehicle measurements to obtain design or test loads, significantly reducing steering system development cycles and testing costs.

[0017] In order to achieve the above objectives, the present invention proposes a vehicle steering system parking load digitization system, which includes:

[0018] A data acquisition device that collects the steering rod force value and the corresponding steering wheel angle value of each vehicle model during the historical parking process;

[0019] An envelope curve generation module generates a steering rod force value-steering wheel angle relationship curve for each vehicle model; and based on the steering rod force value-steering wheel angle relationship curve for each vehicle model, draws a maximum envelope curve of all steering rod force value-steering wheel angle relationship curves;

[0020] The control point selection module performs the following steps:

[0021] a: Set several groups of control points based on the maximum steering wheel angle and maximum rack force of the steering system of each vehicle model, where the abscissa of each control point is the maximum steering wheel angle multiplied by the set percentage, and the ordinate of each control point is the maximum rack force multiplied by the set percentage; the control points are plotted based on the abscissa and ordinate of each control point;

[0022] b: Optimizing the horizontal and vertical coordinates of each control point so that each control point continuously approaches the maximum envelope;

[0023] c: Connect the optimized control points to obtain the control line;

[0024] d: Determine whether the control line completely covers the maximum envelope. If so, output the control line to the vehicle steering system control module; if not, return to step a.

[0025] Furthermore, in the vehicle steering system parking load digitization system of the present invention, the steering rod force value includes a left steering rod force value and a right steering rod force value.

[0026] Furthermore, in the vehicle steering system parking load digitization system of the present invention, there are 15-20 groups of control points.

[0027] Another object of the present invention is to provide a vehicle platform, which includes a vehicle steering system and the vehicle steering system parking load digitization system mentioned above, and the vehicle steering system parking load digitization system transmits the control line to the vehicle steering system control module to adjust and control the steering system.

[0028] The vehicle steering system parking load digitization method described in this invention, based on analysis of historical measurement data, automatically distributes the steering system load distribution to the load associated with the steering angle and the designed rack force using influencing factors, thereby resolving the data source issue for steering system loads. This method eliminates the need for full vehicle measurements to obtain design or test loads, significantly reducing steering system development cycles and testing costs.

[0029] The vehicle steering system parking load digitization system of the present invention also has the above-mentioned beneficial effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 A flowchart showing the steps of a method for digitizing parking load of a vehicle steering system according to an embodiment of the present invention is shown.

[0031] Figure 2The figure shows the relationship curve between the steering rod force and the steering wheel angle of a vehicle model in a specific embodiment of the present invention.

[0032] Figure 3 A group of steering rod force-steering wheel angle relationship curves for 12 types of vehicles in a specific embodiment of the present invention is shown.

[0033] Figure 4 The maximum envelope curve drawn by a group of steering rod force-steering wheel angle relationship curves based on 12 types of vehicles in a specific embodiment of the present invention is shown.

[0034] Figure 5 The percentage conversion of the horizontal and vertical axes of the envelope is shown as an example.

[0035] Figure 6 The figure schematically shows a schematic diagram of solving the optimal xi, yi and y'i of the control points in a specific embodiment of the present invention.

[0036] Figure 7 The output control lines in a specific embodiment of the present invention are shown. DETAILED DESCRIPTION

[0037] The vehicle steering system parking load digitization method and system described in the present invention will be further explained and illustrated below in conjunction with the accompanying drawings and specific embodiments. However, such explanation and illustration do not constitute an undue limitation to the technical solution of the present invention.

[0038] In some embodiments of the present invention, a vehicle steering system parking load digitization system includes:

[0039] A data acquisition device that collects the steering rod force value and the corresponding steering wheel angle value of each vehicle model during the historical parking process;

[0040] An envelope curve generation module generates a steering rod force value-steering wheel angle relationship curve for each vehicle model; and based on the steering rod force value-steering wheel angle relationship curve for each vehicle model, draws a maximum envelope curve of all steering rod force value-steering wheel angle relationship curves;

[0041] The control point selection module performs the following steps:

[0042] a: Set several groups of control points based on the maximum steering wheel angle and maximum rack force of the steering system of each vehicle model, where the abscissa of each control point is the maximum steering wheel angle multiplied by the first percentile of the setting, and the ordinate of each control point is the maximum rack force multiplied by the second percentile of the setting; plot the control points based on the abscissa and ordinate of each control point;

[0043] b: Optimizing the horizontal and vertical coordinates of each control point so that each control point continuously approaches the maximum envelope;

[0044] c: Connect the optimized control points to obtain the control line;

[0045] d: Determine whether the control line completely covers the maximum envelope. If so, output the control line to the vehicle steering system control module; if not, return to step a.

[0046] Figure 1 A flowchart showing the steps of a method for digitizing parking load of a vehicle steering system according to an embodiment of the present invention is shown.

[0047] like Figure 1 As shown, in this embodiment, the method for digitizing the parking load of a vehicle steering system includes the following steps:

[0048] Step 0: Collect the steering rod force value and the corresponding steering wheel angle value of each vehicle model during the parking process.

[0049] Step 1: Generate the steering rod force-steering wheel angle relationship curve for each vehicle model.

[0050] Figure 2 The figure shows, by way of example, a steering rod force-steering wheel angle relationship curve for a vehicle model in a specific embodiment of the present invention, wherein curve I represents the right steering rod force-steering wheel angle relationship curve, and curve II represents the left steering rod force-steering wheel angle relationship curve. Figure 2 The horizontal axis is the steering wheel angle, unit is °, and the vertical axis is the steering rod force value, unit is N.

[0051] By collecting the steering rod force value and the corresponding steering wheel angle value of each vehicle model, the steering rod force value-steering wheel angle relationship curve of all vehicle models can be obtained.

[0052] Figure 3 The relationship curves between steering rod force and steering wheel angle for 12 types of vehicles in a specific embodiment of the present invention are exemplarily shown.

[0053] from Figure 3 As can be seen in the chart, data from 12 historical vehicle models are presented on the same graph, encompassing different axle loads and tire sizes. The group of graphs showing the relationship between steering rod force and steering wheel angle reveal a consistent trend in steering system load distribution, with only slight variations in extreme values ​​depending on the vehicle model and configuration.

[0054] Step 2: Based on the steering rod force-steering wheel angle relationship curves of various vehicle models, draw the maximum envelope of all steering rod force-steering wheel angle relationship curves.

[0055] Figure 4 The maximum envelope curve drawn based on the steering rod force value-steering wheel angle relationship curve group of the above 12 types of vehicles in a specific embodiment of the present invention is exemplarily shown.

[0056] Step 3: Determine the maximum steering wheel angle and maximum rack force of the steering system for each vehicle model. For each vehicle model, its maximum steering wheel angle and maximum rack force are set known quantities.

[0057] For each vehicle platform, the maximum steering wheel angle a and maximum rack force FZ of the steering system are determined at the beginning of design. For example, in one specific embodiment, the maximum steering wheel angle a is 530° and the maximum rack force FZ is 8000N. The steering system parking load digitization method subsequently uses the maximum steering wheel angle a and maximum rack force FZ as the basis for deriving other load levels.

[0058] Step 4: Based on the maximum steering wheel angle and maximum rack force, several groups of control points are set. The abscissa of each control point is the maximum steering wheel angle a multiplied by a set first percentile xi, and the ordinate of each control point is the maximum rack force Fz multiplied by a set second percentile (yi when representing the left steering rod force, y'i when representing the right steering rod force). The control points are then plotted based on their abscissas and ordinates. For example, for the i-th group of control points, the abscissa angle value for the left steering rod is xi%a, and the ordinate steering rod force value is yi%Fz; for the right steering rod, the abscissa angle value is xi%a, and the ordinate steering rod force value is y'i%Fz. Table 1 shows 17 groups of control points selected based on the full steering range (specifically, steering wheel fully right, fully left, and return to center) to control the steering wheel angle and left and right steering rod forces, respectively, in one embodiment of the present invention.

[0059] Table 1.

[0060]

[0061] Note: Table 2 is for a maximum steering wheel angle a = 530° and a maximum rack force Fz = 80,000N

[0062] Theoretically, the horizontal and vertical coordinates of the points on the maximum envelope obtained in step 2 can be expressed as percentages of the maximum steering wheel angle a, and the vertical coordinate can also be expressed as percentages of the maximum rack force load FZ, such as Figure 5As shown, the horizontal coordinate of the point on the envelope can be converted into the form of percentage multiplied by the maximum steering wheel angle a, and the vertical coordinate can be converted into the form of percentage multiplied by the maximum rack force FZ. Each point on the envelope can be processed in this way, so that the normalized load digital table of the relationship between the steering rod force and the angle can be obtained as shown in Table 2, where xj represents the percentage of the current steering wheel angle and the maximum steering wheel angle a, and yj and y'j represent the percentage of the current left and right steering rod force values ​​and the maximum rack force FZ, respectively.

[0063] Table 2.

[0064]

[0065]

[0066] Theoretically, as long as the points on the envelope are divided finely enough, an infinite number of points can be taken, so an infinite number of groups of control points can be set, and the lines connecting these control points will infinitely approach the envelope. However, in the present invention, in order to simplify the model, reduce the number of actions during the operation of the test bench and the amount of calculation of the controller, under the premise that a limited number of control points can cover the envelope, the present invention selects 15-20 groups of control points, such as the 17 groups mentioned above, based on the characteristics of the steering load curve and continuous iterations in long-term work, so as to better take into account the curve envelope effect and the amount of calculation of the test bench. It should be noted that these control points are not points on the envelope, but are determined according to the range of the maximum steering wheel angle and the maximum rack force and the set percentage.

[0067] Step 5: The variables xi, yi and y'i can be adjusted and iterated to find a relatively optimal solution by setting initial values, thereby optimizing the horizontal and vertical coordinates of each control point so that each control point continuously approaches the maximum envelope.

[0068] As mentioned above, solving the optimal xi, yi and y'i is the process of the curve constructed by digital load continuously approaching the envelope, such as Figure 6As shown, taking the third group of control points as an example, the initial xi, yi and y'i are set to 40, 46, and -40 respectively. It is found that the control points at this time are far away from the corresponding points on the envelope (the two correspond to the same steering wheel angle). Although the load corresponding to the constructed curve can cover the envelope, the constructed curve load is larger than the envelope load. This constructed curve load as a test signal will cause the damage to the parts caused by the bench loading to be greater than the actual damage to the parts on the road, that is, the bench load is too strong. Therefore, it is necessary to adjust the xi, yi and y'i values ​​again to make the curve of the constructed load as close to the envelope as possible. For the third group of control points shown in the figure, the most ideal values ​​should be 40, 36, and -30. And so on. For other control points, the optimal xi, yi and y'i values ​​are found in this way. Connect the optimized control points to obtain the control line.

[0069] Step 6: Determine whether the control line completely covers the maximum envelope. If so, output the control line. Figure 7 The output control line of a specific embodiment of the present invention is exemplarily shown; if the judgment is otherwise, return to step 4.

[0070] Correspondingly, in another embodiment of the present invention, a vehicle platform is provided. The vehicle platform is basically the same in structure as the existing vehicle platform and also includes a vehicle steering system. The difference is that it also includes the vehicle steering system parking load digitization system as described above. The vehicle steering system parking load digitization system obtains a control line according to the vehicle steering system parking load digitization method described above, and then transmits the control line to the vehicle steering system control module to adjust and control the steering system.

[0071] The steering system load digitization method and system described in the present invention can solve the problem of test load source once and for all. The load no longer needs to be obtained through vehicle measurement, thereby significantly reducing the development cycle and test costs of the steering system.

[0072] The combination of the various technical features in this case is not limited to the combination described in the claims of this case or the combination described in the specific embodiments. All technical features recorded in this case can be freely combined or combined in any way unless there is a contradiction between them.

[0073] It should also be noted that the above-listed embodiments are merely specific embodiments of the present invention. Obviously, the present invention is not limited to the above-listed embodiments. Similar variations or modifications that can be directly derived from or easily conceived by those skilled in the art based on the disclosure of the present invention should fall within the scope of protection of the present invention.

Claims

1. A method for digitizing parking load of a vehicle steering system, characterized in that: Including steps: 100: Collect the steering rod force values ​​and the corresponding steering wheel angle values ​​of each vehicle model during the historical parking process; 200: Generate a steering rod force-steering wheel angle relationship curve for each vehicle model; 300: Based on the steering rod force-steering wheel angle relationship curves of various vehicle models, the maximum envelope of all steering rod force-steering wheel angle relationship curves is drawn; 400: Based on the maximum steering wheel angle and maximum rack force of the steering system of each vehicle model, a plurality of control points are set, wherein the abscissa of each control point is the maximum steering wheel angle multiplied by a first percentile of the setting, and the ordinate of each control point is the maximum rack force multiplied by a second percentile of the setting; the control points are plotted based on the abscissa and ordinate of each control point; 500: Optimizing the horizontal coordinate and the vertical coordinate of each control point so that each control point continuously approaches the maximum envelope; 600: Connect the optimized control points to obtain a control line; 700: Determine whether the control line completely covers the maximum envelope line. If yes, output the control line; if no, return to step 400.

2. The method for digitizing parking load of a vehicle steering system according to claim 1, wherein: The steering rod force value includes a left steering rod force value and a right steering rod force value.

3. The method for digitizing parking load of a vehicle steering system according to claim 1, wherein: There are 15-20 groups of control points.

4. A vehicle steering system parking load digitization system, characterized in that: include: A data acquisition device that collects the steering rod force value and the corresponding steering wheel angle value of each vehicle model during the historical parking process; An envelope curve generation module generates a steering rod force value-steering wheel angle relationship curve for each vehicle model; and based on the steering rod force value-steering wheel angle relationship curve for each vehicle model, draws a maximum envelope curve of all steering rod force value-steering wheel angle relationship curves; The control point selection module performs the following steps: a: Set several groups of control points based on the maximum steering wheel angle and maximum rack force of the steering system of each vehicle model, where the abscissa of each control point is the maximum steering wheel angle multiplied by the first percentile of the setting, and the ordinate of each control point is the maximum rack force multiplied by the second percentile of the setting; plot the control points based on the abscissa and ordinate of each control point; b: Optimizing the horizontal and vertical coordinates of each control point so that each control point continuously approaches the maximum envelope; c: Connect the optimized control points to obtain the control line; d: Determine whether the control line completely covers the maximum envelope. If so, output the control line to the vehicle steering system control module; if not, return to step a.

5. The vehicle steering system parking load digitization system according to claim 4, characterized in that: The steering rod force value includes a left steering rod force value and a right steering rod force value.

6. The vehicle steering system parking load digitization system according to claim 4, characterized in that: There are 15-20 groups of control points.

7. A vehicle platform comprising a vehicle steering system, characterized in that: It also includes a vehicle steering system parking load digitization system as described in any one of claims 4 to 6, and the vehicle steering system parking load digitization system transmits the control line to a vehicle steering system control module to adjust and control the steering system.

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