A Steering System Limit Position Calibration Method Based on Dynamic Analysis

Abstract

The present invention provides a steering system extreme position verification method based on dynamic analysis, comprising the following steps: collecting modeling parameters and establishing a model; performing steering analysis; establishing a rectangular coordinate system axis0 with P0 as the origin; obtaining projections P1' and P2' of P1 and P2 in the Z=0 plane of the coordinate system axis0; connecting the angles of P1', P2' and P0; obtaining the length of the steering knuckle arm; and verifying the angle and length of the steering knuckle arm. The steering system extreme position verification method based on dynamic analysis described in the present invention is suitable for verifying the rationality of the extreme position movement of the automobile steering system. In the early stage of design and development, simulation analysis is used to reduce the risk of steering jamming and failure to return to the center under the actual vehicle state, reduce the number of road test rounds, and shorten the development cycle; the kingpin penetration point position is obtained by calculating the kingpin position characteristic point, the kingpin inclination angle, the kingpin caster angle and the ground height.

Description

Technical Field

[0001] The invention belongs to the field of automobile performance development and testing, and in particular relates to a steering system extreme position calibration method based on dynamics analysis. Background Art

[0002] During the chassis design and development process, it is necessary to check whether the steering system will get stuck at the extreme position. The commonly used verification indicators are the knuckle arm length and the knuckle arm angle. When the knuckle arm length is too small and the knuckle arm angle is close to 0 degrees or 180 degrees, the steering system is at risk of getting stuck. The coordinates of the inner and outer points of the steering rod can be directly tested and obtained during the steering process. The McPherson and single-ball joint double-wishbone suspensions have real kingpin axes, which can be directly tested and obtained during the steering process. The verification can be completed through the DMU function of general 3D software; while the kingpin of the double-ball joint double-wishbone suspension is a virtual axis and cannot be directly tested, which greatly increases the difficulty of verification. This patent uses multi-body simulation software to output information related to the steering kingpin, which solves the limitation that the virtual kingpin is difficult to obtain. Then, through the coordinate conversion of the inner and outer points of the steering rod, the extreme position verification of the steering system can be effectively completed. Summary of the invention

[0003] In view of this, the present invention aims to propose a steering system limit position verification method based on dynamic analysis, so as to provide a method for quickly and effectively completing the verification of the rationality of the steering system limit position during the chassis design stage.

[0004] To achieve the above object, the technical solution of the present invention is achieved as follows:

[0005] A method for checking the extreme position of a steering system based on dynamic analysis comprises the following steps:

[0006] S1. Collect modeling parameters and establish ADAMS dynamic front suspension model;

[0007] S2. Establish marker points and measure at the inner and outer points of the steering rod of the front suspension model;

[0008] S3, conducting steering analysis on the front suspension model;

[0009] S4, using the software post-processing function to output the kingpin inclination angle, the kingpin caster angle, and the coordinate positions P0, P1, and P2 in the vehicle coordinate system;

[0010] S5, establish a coordinate system axis0 with the kingpin position feature point P0 as the origin, and the Z axis of the coordinate system coincides with the kingpin axis;

[0011] S6, obtaining the projection P1' of P1 in the Z=0 plane of the coordinate system axis0 through the transformation matrix, and obtaining the projection P2' of P2 in the Z=0 plane of the coordinate system axis0 through the transformation matrix;

[0012] S7, connecting the angle formed by P1', P2' and P0 to form line segment P1'P0, line segment P2'P0 and line segment P2'P1';

[0013] S8, the product of the length of the line segment P2'P0 and the sine value of the steering knuckle arm angle is the steering knuckle arm length L;

[0014] S9. Check the steering knuckle arm angle and steering knuckle arm length respectively.

[0015] Furthermore, in step S4, the coordinates of P0 are (x0, y0, z0), the coordinates of P1 are (x10, y10, z10), and the coordinates of P2 are (x20, y20, z20).

[0016] Furthermore, in step S6, the coordinates of P1' are (x1, y1, 0), and the coordinates of P2' are (x2, y2, 0).

[0017] Furthermore, the conversion matrix in step S6 is as follows:

[0018]

[0019]

[0020]

[0021] Among them, kingpin_incl_angle is the kingpin inclination angle, and caster_angle is the kingpin caster angle.

[0022] Furthermore, in step S7, the length of the line segment P1'P0 is L1, the length of the line segment P2'P0 is L2, and the length of the line segment P2'P1' is L3.

[0023] Furthermore, the length L1 of the line segment P1'P0 is: L1 = sqrt(x1 2 +y1 2 ), the length L2 of the line segment P2'P0 is: L2 = sqrt(x2 2 +y2 2 ), the length L3 of the line segment P2'P1' is: L3 = sqrt[(x1-x2) 2 +(y1-y2) 2 )].

[0024] Compared with the prior art, the steering system limit position verification method based on dynamic analysis described in the present invention has the following advantages:

[0025] (1) The method for checking the extreme position of a steering system based on dynamic analysis described in the present invention is reasonably designed and suitable for checking the rationality of the extreme position movement of an automobile steering system. In the early stage of design and development, simulation analysis can be used to reduce the risk of steering jamming and inability to return to the center under actual vehicle conditions, reduce the number of road test rounds, shorten the development cycle, and reduce costs. At the same time, the steering knuckle arm length at different turning angles can be used to check the steering tie rod force and steering rack force. The kingpin penetration point position can be calculated using the kingpin position characteristic point P0, the kingpin inclination angle, the kingpin caster angle, and the ground height. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0027] Figure 1 A method for checking the extreme position of a steering system based on dynamic analysis according to an embodiment of the present invention is a top view of the positions of the kingpin axis and the inner and outer points of the steering rod in the vehicle coordinate system;

[0028] Figure 2 A side view of the positions of the kingpin axis and the inner and outer points of the steering rod in the vehicle coordinate system of a steering system limit position verification method based on dynamic analysis according to an embodiment of the present invention;

[0029] Figure 3 A rear view of the positions of the kingpin axis and the inner and outer points of the steering rod in the vehicle coordinate system according to a method for checking the extreme position of a steering system based on dynamic analysis according to an embodiment of the present invention;

[0030] Figure 4 A schematic diagram of a steering knuckle arm angle and a steering knuckle arm length of a steering system limit position verification method based on dynamic analysis according to an embodiment of the present invention;

[0031] Figure 5 A schematic diagram of a McPherson suspension in a method for checking the extreme position of a steering system based on dynamic analysis according to an embodiment of the present invention;

[0032] Figure 6 A schematic diagram of a single ball joint double wishbone suspension in a steering system limit position verification method based on dynamic analysis according to an embodiment of the present invention;

[0033] Figure 7 A schematic diagram of a double-ball joint double-wishbone suspension in a steering system limit position verification method based on dynamic analysis according to an embodiment of the present invention;

[0034] Figure 8 A schematic diagram of a five-link suspension in a steering system limit position verification method based on dynamic analysis according to an embodiment of the present invention;

[0035] Fig. 9 The present invention is a flowchart of a steering system limit position rationality verification method based on dynamic analysis described in an embodiment of the present invention. DETAILED DESCRIPTION

[0036] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0037] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying 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 limiting the present invention. In addition, the terms "first", "second", and the like are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first", "second", and the like may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0038] In the description of the present invention, it should be noted that, 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 it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood by specific circumstances.

[0039] The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments.

[0040] Glossary:

[0041] ADAMS: Adams, which stands for Automatic Dynamic Analysis of Mechanical Systems, is a virtual prototype analysis software developed by MSC Corporation of the United States.

[0042] McPherson suspension: In simple terms, it is a front suspension named after an automobile designer. It was invented by McPherson and is still used in many models today. The wide application of McPherson in the front suspension of automobiles is unmatched by other suspensions. From high-performance cars such as BMW M3 and Porsche 911 to small cars such as Fiat STILO and Ford FOCUS, and even the domestic Hafei van, the front suspension adopts the McPherson design.

[0043] like Figures 1 to 9 As shown, a method for checking the extreme position of a steering system based on dynamic analysis comprises the following steps:

[0044] S1. Collect modeling parameters (collect modeling parameters such as hard point position, bushing stiffness, topological structure, etc. of front suspension and steering system) and establish ADAMS dynamic front suspension model;

[0045] S2. Establishing Marker (a mark point that can move with the corresponding component) points and Measure (outputting the real-time position information of the Marker point) at the inner and outer points of the steering tie rod of the front suspension model, so as to output the real-time positions of the inner and outer points of the steering tie rod;

[0046] S3, performing steering analysis on the front suspension model, with the steering wheel input changing continuously from the left limit to the right limit;

[0047] S4, using the software post-processing function to output the kingpin inclination angle (kingpin_incl_angle), the kingpin caster angle (caster_angle), and the coordinate positions P0 (kingpin_location), P1, and P2 in the vehicle coordinate system;

[0048] S5, establish a coordinate system axis0 with the kingpin position feature point P0 as the origin, and the Z axis of the coordinate system coincides with the kingpin axis;

[0049] S6, obtaining the projection P1' of P1 in the Z=0 plane of the coordinate system axis0 through the transformation matrix, and obtaining the projection P2' of P2 in the Z=0 plane of the coordinate system axis0 through the transformation matrix;

[0050] S7, the angle formed by connecting P1', P2' and P0 is the toggle angle, and line segments P1'P0, P2'P0 and P2'P1' are formed;

[0051] S8, the product of the length of the line segment P2'P0 and the sine value of the steering knuckle arm angle is the steering knuckle arm length L;

[0052] S9. Check the steering knuckle arm angle toggle angle and the steering knuckle arm length L respectively. This verification method is reasonably designed and suitable for checking the rationality of the extreme position movement of the automobile steering system. It can use simulation analysis methods in the early stage of design and development to reduce the risk of steering jamming and failure to return to the center under the actual vehicle state, reduce the number of road test rounds, shorten the development cycle, and reduce costs; at the same time, the steering knuckle arm length at different turning angles can be used to check the steering rod force and steering rack force; the kingpin penetration point position can be calculated using the kingpin position characteristic point P0, the kingpin inclination angle, the kingpin caster angle and the ground height.

[0053] In step S4, the coordinates of P0 are (x0, y0, z0), the coordinates of P1 are (x10, y10, z10), and the coordinates of P2 are (x20, y20, z20).

[0054] In step S6, the coordinates of P1' are (x1, y1, 0), and the coordinates of P2' are (x2, y2, 0).

[0055] In the specific implementation example, the modeling parameters such as the hard point position, bushing stiffness, and topological structure of the front suspension and steering system are first collected to establish an ADAMS dynamic model; Marker points and corresponding measures (used to output the real-time positions of the inner and outer points of the steering rod) are established at the inner and outer points of the steering rod to perform steering analysis, and the steering wheel input changes continuously from the left limit to the right limit; the kingpin inclination angle (kingpin_incl_angle) and the kingpin caster angle (caster_angle) in the output parameters are used to calculate the kingpin position feature point P0 (kingpin_loc ation, corresponding coordinates are x0, y0, z0) as the origin to establish a rectangular coordinate system axis0, the Z axis of the coordinate system coincides with the kingpin axis; obtain the projection P1' of the inner point P1 of the steering rod (coordinates are x10, y10, z10) in the Z=0 plane of the coordinate system axis0 and its coordinates (x1, y1, 0); obtain the projection P2' of the outer point P2 of the steering rod (coordinates are x20, y20, z20) in the Z=0 plane of the coordinate system axis0 and its coordinates (x2, y2, 0); the angle formed by connecting P1', P2' and P0 is the toggle angle; the product of the length of the line segment P2'P0 and the sine value of the steering knuckle angle is the steering knuckle length; check the steering knuckle angle θ min <toggle angle<θ max ; Check the steering knuckle arm length>L min .

[0056] The conversion matrix in step S6 (conversion matrix from the vehicle coordinate system to the coordinate system axis0) is as follows:

[0057]

[0058]

[0059]

[0060] Among them, kingpin_incl_angle is the kingpin inclination angle, caster_angle is the kingpin caster angle, the coordinates of the inner point P1 of the steering rod in the vehicle coordinate system are (x10, y10, z10), the coordinates of the outer point P2 of the steering rod in the vehicle coordinate system are (x20, y20, z20), the coordinates of the kingpin position feature point P0 in the vehicle coordinate system are (x0, y0, z0), P0 is the origin of the coordinate system axis0, P1' is the projection of P1 in the Z=0 plane of the coordinate system axis0, and the coordinates are (x1, y1, 0); P2' is the projection of P2 in the Z=0 plane of the coordinate system axis0, and the coordinates are (x2, y2, 0).

[0061] The length of the line segment P1'P0 in step S7 is L1, and the length L1 formula of the line segment P1'P0 is: L1=sqrt(x1 2 +y1 2 ); the length of the line segment P2'P0 is L2, and the length L2 of the line segment P2'P0 is: L2 = sqrt(x2 2 +y2 2 ); the length of the line segment P2'P1' is L3, and the length L3 formula of the line segment P2'P1' is: L3=sqrt[(x1-x2) 2 +(y1-y2) 2 )].

[0062] In a specific embodiment, the knuckle arm length L can be obtained according to the cosine theorem:

[0063] L1 2 =L2 2 +L3 2 -2*L2*L3*cos(toggle angle);

[0064] toggle angle = arccos[(-L1 2 +L2 2 +L3 2 ) / 2*L2*L3];

[0065] L = L2*sin(toggle angle).

[0066] like Figure 5 The figure shows a McPherson suspension, where the kingpin axis is the straight line connecting the mounting point A on the shock absorber and the outer point B of the lower arm;

[0067] like Figure 6 As shown, it is a double wishbone suspension, and the kingpin axis is a straight line connecting the outer point A of the upper wishbone and the outer point B of the lower wishbone;

[0068] like Figure 7 As shown, it is a double ball joint double wishbone suspension, and the kingpin axis is the straight line connecting the outer points A and B' of the upper wishbone (the intersection of the rod CD and the extension line of the rod EF);

[0069] like Figure 8 As shown, it is a five-link suspension, and the kingpin axis is a straight line connecting A' (the intersection of the extension line of the rod GH and the rod IJ) and B' (the intersection of the extension line of the rod CD and the rod EF).

[0070] Example 1

[0071] During the chassis design and development process, the layout of the steering system, especially the inner and outer points of the steering rod, has an important impact on the steering and self-centering performance of the vehicle, and requires strict design verification. After the hard points of the suspension and steering system are initially determined, the front suspension dynamics model is established. In addition to the commonly used verification indicators such as bump steer, roll steer, percent ackerman, steering rack travel, and minimum turning radius, it is also necessary to verify whether the steering system is stuck at the extreme position. Through simulation analysis, the steering wheel is simulated to turn from one extreme position to the other extreme position, and the kingpin inclination angle, kingpin caster angle, kingpin position feature point, steering rod inner point coordinates, steering rod outer point coordinates are simulated and output; the rectangular coordinate system axis0 is established with the kingpin position feature point as the origin, the coordinate system Z axis coincides with the steering kingpin, the inner and outer points of the steering rod are projected onto the Z=0 plane of the coordinate system axis0, and the angle formed by connecting P1', P2' and P0 in the projection plane is the steering knuckle arm angle (toggle angle), and the product of the steering rod length and the sine value of the steering knuckle arm angle is the steering knuckle arm length; the steering knuckle arm angle θ is checked min <Toggle angle<θ max ; Check the steering knuckle arm length>L min .

[0072] Taking a certain suspension as an example, at the right turn limit position, the relevant parameters of the right suspension are:

[0073] Kingpin inclination angle 6.7643, kingpin caster angle 15.2446, kingpin position feature point P0 (711.80, 750.60, 519.70), steering rod inner point coordinates P1 (952.00, 310.00, 461.00), steering rod outer point coordinates P2 (841.00, 592.10, 479.60);

[0074] Through coordinate transformation P1'(247.18,-436.76,0.00), P2'(247.18,-436.76,0.00);

[0075] L2 length 207.91mm, L1 length 501.86mm, L3 length 300.46mm;

[0076] The steering knuckle arm angle is 161.3 degrees;

[0077] Steering knuckle arm length L = 66.6 mm.

[0078] At the left turn limit position, the relevant parameters of the right suspension are:

[0079] Kingpin inclination angle 3.8718, kingpin caster angle 4.8159, kingpin position characteristic point P0 (789.14, 734.63, 501.59), steering rod inner point coordinates P1 (952.00, 479.96, 460.87), steering rod outer point coordinates P2 (927.82, 782.20, 477.70);

[0080] Through coordinate transformation P1'(167.84,-252.49,0.00), P2'(140.09,48.81,0.00);

[0081] L2 length 148.35mm, L1 length 303.18mm, L3 length 302.57mm;

[0082] The steering knuckle arm angle is 76.1 degrees;

[0083] Steering knuckle arm length L = 144.0 mm. Note: deg is an angle unit in CSS, representing degree.

[0084] Example 2

[0085] Taking a front steering gear suspension as an example, at the right turn limit position, the relevant parameters of the right suspension are

[0086] Kingpin inclination angle 6.6387, kingpin caster angle 12.5753, kingpin position characteristic point P0 (-61.97, 807.72, 15.43), steering rod inner point coordinates P1 (-167.21, 496.56, -74.71), steering rod outer point coordinates P2 (-161.43, 871.91, -79.38);

[0087] Through coordinate transformation P1'(-77.83,-322.50,0.00), P2'(-71.03,49.89,0.00);

[0088] L2 length 86.80mm, L1 length 331.76mm, L3 length 372.46mm;

[0089] The steering knuckle arm angle is 55.96 degrees, which meets the 30 degree requirement. <Toggle angle<150deg。

[0090] The length of the steering knuckle arm is L=71.93mm, satisfying L>65mm.

[0091] At the left turn limit position, the relevant parameters of the right suspension are:

[0092] Kingpin inclination angle 0.3708, kingpin caster angle 2.1394, kingpin position characteristic point P0 (23.53, 758.99, -2.21), steering rod inner point coordinate P1 (-167.20, 325.45, -74.70), steering rod outer point coordinate P2 (-145.23, 699.44, -99.25);

[0093] Through coordinate transformation P1'(-164.96,-444.66,0.00), P2'(-137.31,-75.39,0.00);

[0094] L2 length 156.64mm, L1 length 474.28mm, L3 length 370.31mm;

[0095] The steering knuckle arm angle is 123.05 degrees, which meets the 30 degree requirement. <Toggle angle<150deg。

[0096] The length of the steering knuckle arm is L=131.29mm, satisfying L>65mm.

[0097] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for checking the extreme position of a steering system based on dynamic analysis, characterized in that: The following steps are involved: S1. Collect modeling parameters and establish ADAMS dynamic front suspension model; S2. Establish marker points and measure at the inner and outer points of the steering rod of the front suspension model; S3. Perform steering analysis on the front suspension model; S4, using the software post-processing function to output the kingpin inclination angle, the kingpin caster angle, and the coordinate positions P0, P1, and P2 in the vehicle coordinate system; S5, establish a coordinate system axis0 with the kingpin position feature point P0 as the origin, and the Z axis of the coordinate system coincides with the kingpin axis; S6, obtain the projection P1' of P1 in the Z=0 plane of the coordinate system axis0 through the transformation matrix, and obtain the projection P2' of P2 in the Z=0 plane of the coordinate system axis0 through the transformation matrix; S7, the angle formed by connecting P1', P2' and P0 is the toggle angle, and line segments P1'P0, P2'P0 and P2'P1' are formed; S8, the product of the length of the line segment P2'P0 and the sine value of the steering knuckle arm angle is the steering knuckle arm length L; S9, check the knuckle arm angle and knuckle arm length respectively, check the knuckle arm angle <toggle angle< ; Check the length of the steering knuckle arm> ; In step S7, the length of the line segment P1'P0 is L1, the length of the line segment P2'P0 is L2, and the length of the line segment P2'P1' is L3; In step S8, the steering knuckle arm length L is obtained according to the cosine theorem: ； ； ； In step S4, the coordinates of P0 are (x0, y0, z0), the coordinates of P1 are (x10, y10, z10), and the coordinates of P2 are (x20, y20, z20); In step S6, the coordinates of P1' are (x1, y1, 0), and the coordinates of P2' are (x2, y2, 0).

2. The method for checking the extreme position of a steering system based on dynamic analysis according to claim 1, characterized in that: The conversion matrix in step S6 is as follows: ； ； ， ； Among them, kingpin_incl_angle is the kingpin inclination angle, and caster_angle is the kingpin caster angle.

3. The method for checking the extreme position of a steering system based on dynamic analysis according to claim 2, characterized in that: The length L1 of the line segment P1'P0 is: , the length L2 of the line segment P2'P0 is: , the length L3 of the line segment P2'P1' is: .

Images