A vector-based deviation correction method and system for a multi-axle all-wheel steering vehicle

Abstract

The present invention provides a vector-based deviation correction method and system for a multi-axis all-wheel steering vehicle. The deviation between the current position and the target position of the vehicle is decomposed into three directions. The shortest path deviation correction is used in each of the three directions to obtain the deviation correction speed vectors of each wheel group. The vectors are superimposed to obtain the resultant deviation correction speed vectors of each wheel group. The deviation correction angles of each wheel group under any offset condition can then be calculated. The proposed vector-based deviation correction operation method for a multi-axis all-wheel steering vehicle is used to control the extension and retraction of the steering cylinder to achieve wheel group steering action and adjust the posture of the multi-axis all-wheel steering vehicle. The present invention has the shortest deviation correction path, fast deviation correction speed, independent control of the deviation correction ratio in each direction and the forward speed of the vehicle, and a flexible and smooth deviation correction process.

Description

Technical Field

[0001] The present invention relates to the technical field of vehicle body posture control of a multi-axle all-wheel steering vehicle, and in particular to a vector deviation correction method and system for a multi-axle all-wheel steering vehicle. Background Art

[0002] Multi-axle all-wheel steering vehicles have extremely strong passability and steering flexibility because the speed and turning angle of each wheel can be independently controlled. They are highly adaptable to non-road conditions such as battlefield bomb disposal and rescue.

[0003] For example, a multi-axle all-wheel steering vehicle, typically a large flatbed transporter with independent steering, is a representative example. When a beam transporter deviates while traveling in tunnels, on roadbeds, or on bridge decks, using traditional steering methods makes it difficult to achieve optimal offset correction and align the vehicle with the track centerline. Furthermore, corrections are prone to frequent yaw and slow correction. To improve the vehicle's flexibility in posture adjustment, it is necessary to calculate the shortest correction path for various deviation scenarios, thereby enhancing both flexibility and stability.

[0004] Based on the above reasons, there is an urgent need to develop a low-cost, easy-to-use, and effective multi-axis all-wheel steering vehicle vector correction method and system. Summary of the Invention

[0005] The purpose of the present invention is to propose a steering control method for multi-axis all-wheel steering vehicles based on vector correction to address the problems of low flexibility and unsatisfactory correction effect in existing steering control methods for multi-axis all-wheel steering vehicles.

[0006] To achieve the above-mentioned purpose, the present invention provides a vector-based correction method for a multi-axle all-wheel steering vehicle. The method decomposes the deviation between the vehicle's current posture and the target posture into three directions, uses the shortest path correction method in each of the three directions to obtain the component vectors of the correction speed of each wheel group, and superimposes these components to obtain the resultant vector of the correction speed of each wheel group. The correction angle of each wheel group under any deviation condition can then be calculated. The method comprises the following steps:

[0007] Step S1: Obtain basic vehicle body parameters;

[0008] Step S2: Obtain the current posture of the vehicle body and calculate the deviation between the current posture of the vehicle and the target posture, that is, obtain the angle deviation α and the longitudinal distance deviation H between the vehicle body and the road centerline;

[0009] Step S3: Correct the deviation in each deviation direction separately using the vector correction method, and calculate the correction speed vector of each wheel group in each deviation direction;

[0010] Step S4: Calculate the correction angle and correction speed of each wheel group: perform vector superposition of the correction speed component vectors of each wheel group in each deviation direction to obtain the correction speed sum vector and correction angle of each wheel group;

[0011] Step S5: Multi-axle all-wheel steering vehicle posture adjustment: The correction angle signal is sent to the steering mechanism, and the correction action is completed by feedback control of the wheel group angle sensor. If each wheel group is performing correction angle control for the first time at this time, the angle of each wheel group is first adjusted to the correction angle, and then the speed control command is sent; when the vehicle starts, the angle of each wheel group can be continuously controlled.

[0012] Furthermore, in step S1, the vehicle is virtually extended so that the virtual turning center of the vehicle is located on the center line of the road.

[0013] Furthermore, the basic parameters of the vehicle body include: ① vehicle body length L; ② vehicle body width W; ③ distances d1 d2 d3 d4 between the four corners of the vehicle and the road boundary; ④ distance X between the wheels along the direction of the vehicle body and the actual center point of the vehicle wi , value range: (-L / 2, L / 2); ⑤ The angle β between the line connecting the wheel center and the vehicle virtual steering center O and the vehicle center line i , value range: (0,π).

[0014] Furthermore, the angle β between the line connecting the wheel center and the vehicle virtual turning center O and the vehicle center line is i , the calculation method is as follows:

[0015]

[0016] When β i When the front wheel angle is indicated,

[0017] When β i When the rear wheel angle is indicated,

[0018] Wherein, i represents the i-th wheel group.

[0019] Furthermore, the deviation between the current vehicle posture and the target posture includes the angular deviation between the vehicle body and the road centerline, with a value range of (-π / 2, π / 2) and is calculated as follows:

[0020]

[0021] The longitudinal distance deviation H is calculated as follows:

[0022] The vehicle length is virtually extended, and two variables are introduced: the vehicle body extension distance L1, and the distance L2 between the actual center point of the vehicle and the virtual turning center O of the vehicle;

[0023] When α>0:

[0024]

[0025] When α<0:

[0026]

[0027]

[0028] H=L2*sinα

[0029] Furthermore, in step S3,

[0030] The vehicle rotates around the virtual center point O to correct the deviation velocity vector:

[0031] Right wheel rotation correction speed vector

[0032] Left wheel rotation correction speed vector

[0033] Where V τRi V is the rotation speed of the right wheel group, τLi The rotation speed of the left wheel group;

[0034] In order to speed up the correction speed of the vehicle body longitudinal distance deviation in the H direction, the H direction is corrected separately:

[0035] H-direction correction velocity vector

[0036] Among them, V h is the vehicle's correction speed in the H direction;

[0037] V-direction correction speed vector

[0038] Where V v is the vehicle's correction speed in the V direction.

[0039] Furthermore, in order to make the deviation in each direction corrected simultaneously within the unit time t and make the correction speed ratio in each direction adjustable, the correction speed ratio factor k in each direction is introduced here. v 、k α 、k h ,ω is the angular velocity of the vehicle body performing rotation correction around the virtual center point O,

[0040] The correction angles of the wheels of the vehicle include:

[0041] Right wheelset correction angle γ R1 γ R2 …γRn , the calculation method is as follows:

[0042]

[0043] Left wheel set deviation correction angle γ L1 γ L2 …γ Ln , the calculation method is as follows:

[0044]

[0045] Among them, the V direction correction ratio coefficient k v , α direction correction proportional coefficient k α , H direction correction ratio coefficient k h .

[0046] Furthermore, the correction velocity vectors of each wheel group of the vehicle include:

[0047] Right wheel deviation correction speed The calculation method is as follows:

[0048]

[0049] Left wheel deviation correction speed The calculation method is as follows:

[0050]

[0051] The present invention also provides a vector-correcting steering system for a multi-axle all-wheel steering vehicle.

[0052] The system comprises: a distance measuring sensor group, an integrated navigation system, a wheel angle sensor group, a controller group, a steering cylinder, and a running wheel group. The controller group is provided with a steering model of a multi-axle all-wheel steering vehicle. The distance measuring sensors are installed at the four corners of the vehicle body, the integrated navigation system is installed at the front of the vehicle, and the wheel angle sensor group is arranged at the upper end of the vertical shaft of the running wheel group. All three are connected to the controller. The distance measuring sensors are used to measure the distance between the four corners of the vehicle and the road boundary when the driving boundary is a wall. The integrated navigation system is used to detect the vehicle body position and calculate the distance between the vehicle body and the road boundary outdoors with a good positioning signal. The wheel angle sensor group is an absolute value wheel angle sensor group used for feedback control of the wheel angle.

[0053] Furthermore, the controller is used to receive signals from a distance measuring sensor group, a combined navigator, and a wheel angle sensor group. The steering model of the multi-axis all-wheel steering vehicle is processed by the multi-axis all-wheel steering vehicle vector correction operation method to control the extension and retraction of the steering cylinder to realize the wheel steering action and adjust its posture.

[0054] Compared with the prior art, the present invention has the following advantages:

[0055] 1. High degree of automation, automatic correction can be achieved without human intervention; 2. The correction path is the shortest. Based on the control principle of vector correction, the shortest path correction is adopted in all directions. The superimposed correction path is the shortest correction path, which can avoid frequent steering of the beam transport wheel group during the correction process; 3. The correction ratio in each direction is adjustable, which increases the flexibility and smoothness of the correction process; 4. High cost performance. The ranging sensor is inexpensive compared to lidar and depth cameras, has high reliability and is easy to maintain; 5. Wide range of applications. It can automatically correct driving outdoors where there is a satellite positioning signal or indoors where the road boundary is a wall. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Figure 1 : Schematic diagram of the system of the present invention;

[0057] Figure 2 : Schematic diagram of the entire mechanical and electrical parts of the present invention;

[0058] Figure 3 : Basic parameter diagram of all-wheel steering vehicle motion control;

[0059] Figure 4 : Analysis diagram of the counterclockwise deflection of an all-wheel steering vehicle;

[0060] Figure 5 : Analysis diagram of clockwise deflection of all-wheel steering vehicle; DETAILED DESCRIPTION

[0061] In order to make the technical problems, technical solutions and beneficial effects to be solved by the embodiments of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0062] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present invention 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 operate in a specific orientation, and therefore cannot be understood as limiting the present invention.

[0063] In the description of the present invention, unless otherwise specified, the term "connection" should be understood in a broad sense, for example, it can refer to a fixed connection, a detachable connection, or an integral connection. For those skilled in the art, the specific meaning of the above terms in the present invention can be understood by those skilled in the art in specific circumstances.

[0064] The implementation process of the present invention is further described in detail below with reference to specific drawings and examples.

[0065] Figure 1 is a schematic diagram of the system of the present invention, Figure 2 This is a schematic diagram of the mechanical and electrical structure of the present invention, comprising: a distance sensor group 1, a wheel angle sensor group 2, a controller group 3, a steering cylinder 4, a running wheel group 5, and an integrated navigation system 6. The controller group 3 receives signals from the distance sensors 1, the integrated navigation system 6, and the wheel angle sensor group 2, and after processing, sends control commands to each steering mechanism. The distance sensors 1 are mounted at the four corners of the beam transport vehicle and connected to the controller. The wheel angle sensor group is connected to the controller. The steering cylinder is connected to the running wheel group 5. The integrated navigation system 6 is mounted at the front of the vehicle and connected to the controller.

[0066] The following combination Figure 3 、 Figure 4 The implementation process of the present invention is further described in detail.

[0067] Step S1: Get Figure 3 The basic parameters of the vehicle body shown are: ① vehicle length L, ② vehicle width W, ③ distances d1, d2, d3, d4 between the four corners of the vehicle and the road boundary, ④ distance between the wheel and the center position of the vehicle X wi ; ⑤ Calculate the angle β between all wheels and the center line of the vehicle according to formula (1) i .

[0068]

[0069] When β i When the front wheel angle is indicated,

[0070] When β i When the rear wheel angle is indicated,

[0071] Step S2: Obtain the deviation between the current posture of the vehicle and the target posture: The current posture of the vehicle is obtained by the distance measurement sensors or integrated navigation system installed at the four corners of the vehicle body, and is calculated according to formula (2), formula (3), formula (34), formula (35), and formula (36) respectively. Figure 3 The deviation between the current position of the vehicle shown and the target position is obtained by using distance measuring sensors or integrated navigation system installed at the four corners of the vehicle body to obtain the angular deviation α between the vehicle body and the road centerline and the longitudinal distance deviation H.

[0072] Angle deviation α, value range: (-π / 2,π / 2);

[0073]

[0074] When the vehicle body deflects counterclockwise, α>0;

[0075] When the vehicle body deflects clockwise, α<0;

[0076] Longitudinal distance deviation H:

[0077] H=L2*sinα, (3)

[0078] When the vehicle moves forward, the center point of the vehicle is on the left side of the road centerline, H>0;

[0079] When the vehicle moves forward, the center point of the vehicle is on the right side of the road centerline, H<0;

[0080] Step S3: Correct the deviation in each deviation direction separately using the vector correction method, and calculate the correction speed vector of each wheel group in each deviation direction;

[0081] In the above embodiment, if Figure 4 As shown in the figure, when the vehicle body deflects counterclockwise, the vehicle rotates clockwise around the virtual center point O to complete the correction:

[0082] Right wheel rotation correction speed vector

[0083] Left wheel rotation correction speed vector

[0084] In order to speed up the correction speed of the vehicle body longitudinal distance deviation in the H direction, the H direction is corrected separately:

[0085] H-direction correction velocity vector

[0086] When H>0,

[0087] When H<0,

[0088] (6) and (7) give

[0089] To allow the vehicle to perform corrections in the α and H directions while moving forward, a virtual offset V is introduced. Its direction is parallel to the road centerline and points in the vehicle's forward direction. This allows for independent correction in the V direction:

[0090] V-direction correction speed vector

[0091] like Figure 5 As shown in the figure, when the vehicle body deflects clockwise, the vehicle rotates counterclockwise around the virtual center point O to complete the correction:

[0092] Right wheel rotation correction speed vector

[0093] Left wheel rotation correction speed vector

[0094] In order to speed up the correction speed of the vehicle body longitudinal distance deviation in the H direction, the H direction is corrected separately:

[0095] H-direction correction velocity vector

[0096] When H>0,

[0097] When H<0,

[0098] (12) and (13) give,

[0099] In order to make the vehicle perform the correction action in the α and H directions while moving forward, a virtual offset V is introduced here, whose direction is parallel to the center line of the road and points to the direction of vehicle movement, and the V direction is corrected separately: the V direction correction speed vector

[0100] In summary:

[0101] The vehicle rotates around the virtual center point O and the correction velocity vector is: (the situation of the left and right wheels is different)

[0102] (4) and (10) give

[0103] (5) and (11) give

[0104] H-direction correction velocity vector (The same situation applies to both left and right wheels)

[0105] (8) and (14) give

[0106] V-direction correction speed vector (The same situation applies to both left and right wheels)

[0107] (9) and (15) give

[0108] In order to make the deviation in each direction corrected simultaneously within the unit time t and make the correction speed ratio in each direction adjustable, the correction speed ratio factor k in each direction is introduced here. v 、k α 、k h ,ω is the angular velocity of the vehicle body performing rotation correction around the virtual center point O, which can be sorted out as follows:

[0109]

[0110] Since this calculation only requires numerical values, it is easy to get:

[0111]

[0112]

[0113]

[0114]

[0115] The vectors of the correction speed in each direction are shown in Table 1: (The actual direction in the following formula is determined by the signs of each term)

[0116] Table 1. Correction velocity vector table in each direction

[0117]

[0118]

[0119] Step S4: Calculate the correction angle and correction speed of each wheel group: perform vector superposition of the correction speed component vectors of each wheel group in each deviation direction to obtain the correction speed sum vector and correction angle of each wheel group;

[0120] The sum of the right wheelset's correcting speed vector:

[0121]

[0122] The sum of the left wheelset's correcting speed vector:

[0123]

[0124] For the convenience of subsequent control, let t=1, V=1, V v =1.

[0125] The summed vectors of the right and left wheel correction velocities are:

[0126]

[0127]

[0128] Right wheel set steering angle:

[0129]

[0130] Left wheel set deviation correction angle:

[0131]

[0132] When the wheel rotates counterclockwise, γ>0;

[0133] When the wheel rotates counterclockwise, γ>0;

[0134] S5: Multi-axle all-wheel steering vehicle posture adjustment: Send the correction angle signal to the steering mechanism, and the wheel angle sensor feedback control completes the correction action. If each wheel group performs the correction angle control for the first time, the wheel angle of each wheel group is adjusted to γ R1 , γ R2 …γ Ri , γ L1 , γ L2 …γ Li , and then send speed control instructions; when the vehicle starts, the steering angle of each wheel group can be continuously controlled.

[0135] Furthermore, in step S1, when the vehicle is traveling on a road section with walls on both sides of the vehicle body, such as a tunnel, a bridge with a slag retaining wall, etc., the distances d1, d2, d3, and d4 between the four corners of the vehicle body and the road boundary are measured by distance measuring sensors at the four corners of the vehicle body, and then the angle deviation α and the longitudinal distance deviation H between the vehicle body and the road centerline are calculated through (34), (35), (36), (2), and (3); when the vehicle is traveling on a road section without walls on both sides of the vehicle body, the angle deviation α and the longitudinal distance deviation H between the vehicle body and the road centerline are directly obtained through the combined navigation system.

[0136] Furthermore, in step S2, the vehicle length is virtually extended, where two variables are introduced: the virtual extension distance L1 of the vehicle body and the distance L2 between the vehicle geometric center point and the coordinate origin in the V direction;

[0137] L1: Make the center point of the extended vehicle be on the center line of the tunnel;

[0138] When the vehicle body deflects clockwise, that is, α>0:

[0139]

[0140] When the vehicle body deflects counterclockwise, that is, α<0:

[0141]

[0142] When the extended part of the vehicle body is located at the rear side of the vehicle, L1>0;

[0143] When the extended part of the vehicle body is located at the front side of the vehicle, L1<0;

[0144] L2: The distance between the vehicle's geometric center and the coordinate origin in the V direction:

[0145]

[0146] When the vehicle's geometric center is located on the positive half of the X-axis, L2>0;

[0147] When the vehicle's geometric center is located on the negative half axis of the X-axis, L2<0.

[0148] Furthermore, in step S3, since the vehicle body rotates around the virtual center point O, the angular deviation α between the vehicle body and the road centerline and the longitudinal distance deviation H can be corrected simultaneously. However, in order to speed up the correction speed of the longitudinal distance deviation H, a correction is performed in the H direction separately; therefore, the ratio of the correction speed in the α direction to the correction speed in the H direction is k α :(k α +k h ). By adjusting k v The size and positive and negative values ​​control the wheel angle corresponding to the vehicle's different moving speeds and directions in the V direction.

[0149] Furthermore, in step S4, if the vehicle only rotates around the virtual center point O, the vehicle satisfies the Ackerman steering principle; if the vehicle only moves in the V direction or the H direction, the wheels of the vehicle are synchronized; therefore, the wheels of the vehicle are divided into vectors according to the deviation correction speed. The sum of the correction velocity vector after superposition During movement, the steering center of each wheel group remains the same, satisfying the Ackermann steering principle.

[0150] The specific embodiments described herein are merely illustrative of the spirit of the present invention. Persons skilled in the art may make various modifications, additions, or substitutions to the described specific embodiments without departing from the spirit of the present invention or exceeding the scope of the appended claims.

Claims

1. A vector-based deviation correction method for a multi-axle all-wheel steering vehicle, characterized in that: The deviation between the vehicle's current and target positions is decomposed into three directions. The shortest path correction is used in each of the three directions to obtain the component vectors of the correction velocity of each wheel group. These vectors are then superimposed to obtain the resultant vector of the correction velocity of each wheel group. The correction angle of each wheel group under any offset condition can then be calculated. This process includes the following steps: Step S1: Obtain basic vehicle body parameters; In step S1, the vehicle is virtually extended so that the virtual turning center of the vehicle is located on the center line of the road; the basic parameters of the vehicle body include: ① body length L; ② body width W; ③ distances d1, d2, d3, d4 between the four corners of the vehicle and the road boundary; ④ distance X between the wheel along the body direction and the actual center point of the vehicle wi , value range: (-L / 2, L / 2); ⑤ The angle β between the line connecting the wheel center and the vehicle virtual steering center 0 and the vehicle center line i , value range: (0,π); Step S2: Obtain the current posture of the vehicle body and calculate the deviation between the current posture of the vehicle and the target posture, that is, obtain the angular deviation α between the vehicle body and the road centerline and the longitudinal distance deviation H; the deviation between the current posture of the vehicle and the target posture includes the angular deviation between the vehicle body and the road centerline, and the value range is (-π / 2, π / 2). The calculation method is as follows: The longitudinal distance deviation H is calculated as follows: The vehicle length is virtually extended, and two variables are introduced: the vehicle body extension distance L1, and the distance L2 between the actual center point of the vehicle and the virtual turning center O of the vehicle; When α>0: When α<0: H=L2*sinα Step S3: Correct the deviation in each deviation direction separately using the vector correction method, and calculate the correction speed vector of each wheel group in each deviation direction; Step S4: Calculate the correction angle and correction speed of each wheel group: perform vector superposition of the correction speed component vectors of each wheel group in each deviation direction to obtain the correction speed sum vector and correction angle of each wheel group; Step S5: Multi-axle all-wheel steering vehicle posture adjustment: The correction angle signal is sent to the steering mechanism, and the correction action is completed by feedback control of the wheel group angle sensor. If each wheel group is performing correction angle control for the first time at this time, the angle of each wheel group is first adjusted to the correction angle, and then the speed control command is sent; when the vehicle starts, the angle of each wheel group can be continuously controlled.

2. The vector-based deviation correction method for a multi-axle all-wheel steering vehicle according to claim 1, characterized in that: The angle β between the line connecting the wheel center and the vehicle virtual steering center O and the vehicle center line i , the calculation method is as follows: When β i When the front wheel angle is indicated, When β i When the rear wheel angle is indicated, Wherein, i represents the i-th wheel group.

3. The vector-based deviation correction method for a multi-axle all-wheel steering vehicle according to claim 2, characterized in that: In the step S3, The vehicle rotates around the virtual center point O to correct the deviation velocity vector: Right wheel rotation correction speed vector : Left wheel rotation correction speed vector : Where V τRi V is the rotation speed of the right wheel group, τLi The rotation speed of the left wheel group; In order to speed up the correction speed of the vehicle body longitudinal distance deviation in the H direction, the H direction is corrected separately: H-direction correction velocity vector : Among them, V h is the vehicle's correction speed in the H direction; V-direction correction speed vector :(V v cosα,-V v sinα), Where V v is the vehicle's correction speed in the V direction.

4. The vector-based deviation correction method for a multi-axle all-wheel steering vehicle according to claim 3, characterized in that: In order to make the deviation in each direction corrected simultaneously within the unit time t and make the correction speed ratio in each direction adjustable, the correction speed ratio factor k in each direction is introduced here. v 、k α 、k h ,ω is the angular velocity of the vehicle body performing rotation correction around the virtual center point O, The correction angles of the wheels of the vehicle include: Right wheelset correction angle γ R1 , γ R2 ...γ Rn , the calculation method is as follows: Left wheel set correction angle γ L1 , γ L2 ...γ Ln , the calculation method is as follows: Among them, α is the deviation between the current vehicle posture and the target posture, including the angle deviation between the vehicle body and the road centerline, and the V direction correction coefficient k v , α direction correction proportional coefficient k α , H direction correction ratio coefficient k h .

5. The vector-based deviation correction method for a multi-axle all-wheel steering vehicle according to claim 4, characterized in that: The correction velocity vectors of each wheel group of the vehicle include: Right wheel deviation correction speed The calculation method is as follows: Left wheel deviation correction speed The calculation method is as follows:

6. A multi-axle all-wheel steering vehicle vector correction steering system, characterized in that: The method for executing the steps of the vector deviation correction method for a multi-axle all-wheel steering vehicle according to claim 1 comprises: a distance sensor group, an integrated navigation system, a wheel group angle sensor group, a controller group, a steering cylinder, and a running wheel group. The controller group is provided with a steering model of the multi-axle all-wheel steering vehicle. The distance sensors are installed at the four corners of the vehicle body, the integrated navigation system is installed at the front of the vehicle, and the wheel group angle sensor group is arranged at the upper end of the vertical shaft of the running wheel group. All three are connected to the controller. The distance sensors are used to measure the distance between the four corners of the vehicle and the road boundary when the vehicle is traveling on a road with a wall as the boundary. The integrated navigation system is used to detect the vehicle body position and calculate the distance between the vehicle body and the road boundary outdoors with a good positioning signal. The wheel group angle sensor group is an absolute value wheel group angle sensor group used to feedback control the wheel group angle.

7. The multi-axle all-wheel steering vehicle vector correction steering system according to claim 6, characterized in that: The controller is used to receive signals from a distance sensor group, an integrated navigator, and a wheel angle sensor group. The steering model of the multi-axis all-wheel steering vehicle is processed by the multi-axis all-wheel steering vehicle vector correction operation method to control the extension and retraction of the steering cylinder to realize the wheel steering action and adjust its posture.

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