A Steering Control Method for a Six-Wheel Rear-Wheel-Drive Unmanned Support Vehicle

Abstract

The present invention relates to a steering control method for a six-wheel rear-wheel drive unmanned support vehicle, and the steps are as follows: 1: Determine the position information and speed of the installation point of the integrated navigation system; 2: Determine the vehicle steering angle coefficient according to the speed of the installation point of the integrated navigation system, and obtain the wheel angular velocity; 3: Calculate the slip ratio calculated based on the sensor during the driving process according to the wheel angular velocity and the speed of the installation point of the navigation system; 4: Obtain the slip ratio based on the empirical model during the driving process according to the type of the road surface on which the vehicle travels; 5: Synthesize the slip ratio calculated based on the sensor and the slip ratio based on the empirical model to obtain the corrected slip ratio; 6: Determine whether the currently corrected slip ratio meets the steering requirements; if the slip ratio is lower than 0.9, proceed to the next step; if the slip ratio is higher than 0.9, send a braking command to the left and right hub motors; 7: Calculate the steering target angular velocity of the left and right drive wheels according to the vehicle steering command. The present invention improves the stability of steering.

Description

Technical Field

[0001] The present invention belongs to the technical field of unmanned vehicle steering, and particularly relates to a steering control method for a six-wheel rear-wheel drive unmanned support vehicle. Background Art

[0002] At present, due to global warming, extreme weather has occurred many times around the world, which not only harms the balance of the natural ecosystem, but also seriously affects human health. China has a large number of fuel vehicles in use, and the exhaust emissions of traditional fuel vehicles have become one of the main sources of environmental pollution. Therefore, it is urgent to vigorously develop pure electric vehicles.

[0003] After changing the drive form of the traditional unmanned support vehicle from a fuel engine to an electric motor, there are more options for the design and control of the steering system. Wheel hub motor drive steering is one of the optimal steering drive methods for pure electric vehicles. Wheel hub motor drive steering realizes vehicle steering by controlling the rotational speed difference between the left and right drive wheels through the wheel hub motors. Wheel hub motor drive steering has the advantages of good flexibility, light weight, and simple control. The current wheel hub motor drive differential steering mainly has the following problems: First, in the process of differential steering modeling, the influence of vehicle slip ratio and vehicle speed on steering is rarely considered simultaneously; Second, when deriving the required rotational speeds of the left and right wheels for steering, the speed at the vehicle speed measurement point is roughly equated to the vehicle centroid speed, resulting in a certain deviation in the target rotational speeds of the left and right drive wheels; Third, the vehicle slip ratio can be calculated through vehicle body sensors or through empirical models. During vehicle driving, the suspension vibration causes relative displacement between the sensor and the wheel, resulting in inaccurate measured wheel speeds. When using an empirical model to estimate the slip ratio, the degree of road surface damage has a greater impact on the result. Currently, the calculation of the slip ratio during the steering process often uses a single theory for estimation, and the reliability and accuracy of the estimation results are relatively low. Summary of the Invention

[0004] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a steering control method for a six-wheel rear-wheel drive unmanned support vehicle.

[0005] The above object of the present invention is achieved by the following technical solutions:

[0006] A steering control method for a six-wheel rear-wheel drive unmanned support vehicle, characterized in that: the drive mode of the support vehicle is that the four front wheels are driven wheels, and the left and right rear wheels are drive wheels, and each drive wheel is respectively provided with a wheel hub motor, including the following steps:

[0007] Step S1: Determine the position information and speed of the installation point of the integrated navigation system on the support vehicle;

[0008] Step S2: Determine the vehicle steering angle coefficient according to the speed of the installation point of the integrated navigation system, and obtain the wheel angular velocity;

[0009] Step S3: Calculate the slip ratio calculated based on the sensor during driving according to the wheel angular velocity and the speed of the navigation system installation point;

[0010] Step S4: Determine the parameters in the Burckhardt slip ratio model according to the type of the road surface on which the vehicle is driving, and obtain the slip ratio based on the empirical model during driving.

[0011] Step S5: Synthesize the slip ratio calculated based on the sensor and the slip ratio based on the empirical model to obtain the corrected slip ratio.

[0012] Step S6: Determine whether the currently corrected slip ratio meets the steering requirements. If the slip ratio is lower than 0.9, proceed to the next step; if the slip ratio is higher than 0.9, send a braking command to the left and right hub motors.

[0013] Step S7: Calculate the steering target angular velocities of the left and right drive wheels according to the vehicle steering command.

[0014] Further, the position information to be determined in Step S1 is: the horizontal distance a from the measurement point of the integrated navigation system to the central axis and the vertical distance b from the rear axle.

[0015] Further, the method for determining the vehicle driving speed in Step S2 is: if the current vehicle speed v measured by the integrated navigation m is less than 80 km / h, the steering angle coefficient λ takes a value of 1.2; if the current vehicle speed v measured by the integrated navigation m is greater than or equal to 80 km / h, the steering angle coefficient λ takes a value of 0.8.

[0016] Further, the slip ratio of the vehicle in Step S3 is determined by the following formula:

[0017]

[0018] In the formula, s c is the slip ratio calculated based on the sensor; v m is the current vehicle speed measured by the integrated navigation, unit: m / s; ω is the wheel angular velocity, unit: rad / s; r is the wheel radius, unit: m.

[0019] Further, the Burckhardt slip ratio model in Step S4 is:

[0020]

[0021] In the formula, C1, C2 and C3 are fitting parameters; μ is the peak road surface adhesion coefficient; s t is the slip ratio based on the empirical model.

[0022] The slip ratio based on the empirical model is obtained through the following formula:

[0023]

[0024] Wherein, C1, C2 and C3 are fitting parameters; s t is the slip ratio based on the empirical model.

[0025] Furthermore, the method for correcting the slip ratio in step S5 is as follows:

[0026] s = s c + GΔs

[0027] Wherein, s is the corrected slip ratio; s c is the slip ratio calculated based on the sensor; s t is the slip ratio based on the empirical model; Δs = s c - s t , which is the difference between the slip ratio calculated based on the sensor and the slip ratio calculated based on the empirical model; G is a variable gain. G is a function expression with respect to |Δs| and changes as |Δs| changes. The specific expression is:

[0028] G = 1 + log 10 |Δs|

[0029] Wherein, G is a variable gain; |Δs| = |s c - s t |, which is the absolute value of the difference between the slip ratio calculated based on the sensor and the slip ratio calculated based on the empirical model.

[0030] Furthermore, if the vehicle receives a left turn command in step S7, the angular velocity of the left drive wheel is calculated by the following formula:

[0031]

[0032] Wherein, ω l is the angular velocity of the left drive wheel, unit: rad / s; s is the corrected slip ratio; v m is the current vehicle speed measured by the integrated navigation, unit: m / s; r is the wheel radius, unit: m; L is the front and rear wheelbase of the six-wheel rear-wheel drive unmanned support vehicle, unit: mm; W is the left and right wheel track of the six-wheel rear-wheel drive unmanned support vehicle, unit: mm; λ is the steering angle coefficient; α m is the steering angle; a is the horizontal distance from the measurement point of the integrated navigation system to the central axis, unit: mm; b is the vertical distance from the measurement point of the integrated navigation system to the rear axle, unit: mm.

[0033] The angular velocity of the right drive wheel is calculated by the following formula:

[0034]

[0035] where ω r is the angular velocity of the right drive wheel, unit: rad / s; s is the corrected slip ratio; v m is the current vehicle speed measured by the integrated navigation, unit: m / s; r is the wheel radius, unit: m; L is the front and rear wheelbase of the six-wheel rear-wheel drive unmanned support vehicle, unit: mm; W is the left and right wheel track of the six-wheel rear-wheel drive unmanned support vehicle, unit: mm; λ is the steering angle coefficient; α m is the steering angle; a is the horizontal distance from the measurement point of the integrated navigation system to the central axis, unit: mm; b is the vertical distance from the measurement point of the integrated navigation system to the rear axle, unit: mm;

[0036] If the vehicle receives a right turn command, the angular velocity of the left drive wheel is calculated by the following formula:

[0037]

[0038] where ω l is the angular velocity of the left drive wheel, unit: rad / s; s is the corrected slip ratio; v m is the current vehicle speed measured by the integrated navigation, unit: m / s; r is the wheel radius, unit: m; L is the front and rear wheelbase of the six-wheel rear-wheel drive unmanned support vehicle, unit: mm; W is the left and right wheel track of the six-wheel rear-wheel drive unmanned support vehicle, unit: mm; λ is the steering angle coefficient; α m is the steering angle; a is the horizontal distance from the measurement point of the integrated navigation system to the central axis, unit: mm; b is the vertical distance from the measurement point of the integrated navigation system to the rear axle, unit: mm.

[0039] The angular velocity of the right drive wheel is calculated by the following formula:

[0040]

[0041] where ω r is the angular velocity of the right drive wheel, unit: rad / s; s is the corrected slip ratio; v m is the current vehicle speed measured by the integrated navigation, unit: m / s; r is the wheel radius, unit: m; L is the front and rear wheelbase of the six-wheel rear-wheel drive unmanned support vehicle, unit: mm; W is the left and right wheel track of the six-wheel rear-wheel drive unmanned support vehicle, unit: mm; λ is the steering angle coefficient; α m is the steering angle; a is the horizontal distance from the measurement point of the integrated navigation system to the central axis, unit: mm; b is the vertical distance from the measurement point of the integrated navigation system to the rear axle, unit: mm.

[0042] Advantages and positive effects of the present invention:

[0043] 1. The steering control method proposed by the present invention fully considers the influence of slip ratio, vehicle speed, and vehicle speed measurement point on steering during the calculation of the steering speeds of the left and right drive wheels, improving the stability of steering.

[0044] 2. During the determination of the slip ratio, the steering control method proposed by the present invention adopts a gain scheduling method to fuse the slip ratio calculated based on sensors and the slip ratio calculated based on an empirical model, making up for the defects in the calculation of a single slip ratio and providing more accurate data for calculating the rotational speeds of the left and right drive wheels during the steering process.

[0045] 3. The steering control method proposed by the present invention has the advantages of strong practicability, simplicity, wide application range, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 is a schematic diagram of the steering model of the present invention, and the intersection point in the figure is the center of steering at the current moment;

[0047] Figure 2 is a flow chart of the steering control method proposed by the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0048] The structure of the present invention will be further described below with reference to the drawings and through embodiments. It should be noted that this embodiment is narrative rather than restrictive.

[0049] The control method proposed by the present invention is applicable to a six-wheel rear-wheel drive unmanned support vehicle, and its specific driving method is as follows: the four front wheels are driven wheels, and the left and right rear wheels are drive wheels. There is a hub motor on each drive wheel, which can independently control the wheel speed on one side. The schematic diagram of the steering model is as shown in the appendix Figure 1 as shown.

[0050] As shown in the appendix Figure 2 as shown, a steering control method for a six-wheel rear-wheel drive unmanned support vehicle includes the following steps:

[0051] Step S1: Determine the position information and speed of the installation point of the integrated navigation system on the support vehicle to be controlled; the position information to be determined is: the horizontal distance a from the measurement point of the integrated navigation system to the central axis of the support vehicle and the vertical distance b from the rear axis. a and b are the installation positions of the integrated navigation system, and their installation positions vary according to the layout of each vehicle. a and b are the positions obtained by measuring the actual vehicle layout. Once the layout of a vehicle is determined, the values of a and b are fixed values. The integrated navigation system is an integral unit that integrates inertial navigation and satellite navigation

[0052] Step S2: Determine the vehicle steering angle coefficient according to the speed of the installation point of the integrated navigation system, and obtain the wheel angular velocity. The vehicle angular velocity is directly obtained from the vehicle control system;

[0053] The method for determining the vehicle driving speed is as follows: If the current vehicle speed v measured by the integrated navigation m is less than 80 km / h, the steering angle coefficient λ takes the value of 1.2; if the current vehicle speed v measured by the integrated navigation m is greater than or equal to 80 km / h, the steering angle coefficient λ takes the value of 0.8.

[0054] Step S3: Calculate the slip ratio calculated based on the sensors during driving according to the wheel angular velocity and the speed at the navigation system installation point; the slip ratio is determined by the following formula:

[0055]

[0056] In the formula, s c is the slip ratio calculated based on the sensors; v m is the current vehicle speed measured by the integrated navigation, unit: m / s; ω is the wheel angular velocity, unit: rad / s; r is the wheel radius, unit: m.

[0057] Step S4: Determine the parameters in the Burckhardt slip ratio model (existing model) according to the type of the vehicle driving road surface, and obtain the slip ratio based on the empirical model during driving. The Burckhardt slip ratio model is:

[0058]

[0059] In the formula, C1, C2, and C3 are fitting parameters; μ is the peak road surface adhesion coefficient; s t is the slip ratio based on the empirical model.

[0060] The slip ratio based on the empirical model is obtained through the following formula:

[0061]

[0062] In the formula, C1, C2, and C3 are fitting parameters; s t is the slip ratio based on the empirical model.

[0063] Step S5: Integrate the slip ratio calculated based on the sensors and the slip ratio based on the empirical model to obtain the corrected slip ratio. The correction formula for the slip ratio is:

[0064] s = s c + GΔs

[0065] In the formula, s is the corrected slip ratio; s c is the slip ratio calculated based on the sensors; s t is the slip ratio based on the empirical model; Δs = s c - s t, is the difference between the slip ratio calculated based on the sensor and the slip ratio calculated based on the empirical model; G is a variable gain; G is a functional expression of |Δs| and changes with the change of |Δs|. The specific expression is:

[0066] G = 1 + log 10 |Δs|

[0067] In the formula, G is a variable gain; |Δs| = |s c - s t |, which is the absolute value of the difference between the slip ratio calculated based on the sensor and the slip ratio calculated based on the empirical model.

[0068] Step S6: Determine whether the currently corrected slip ratio meets the steering requirements; if the slip ratio is lower than 0.9, proceed to the next step; if the slip ratio is higher than 0.9, send a braking command to the left and right hub motors to stop the vehicle.

[0069] Step S7: Calculate the steering target angular velocities of the left and right drive wheels according to the vehicle steering command.

[0070] If the vehicle receives a left turn command, the angular velocity of the left drive wheel is calculated by the following formula:

[0071]

[0072] In the formula, ω l is the angular velocity of the left drive wheel, unit: rad / s; s is the corrected slip ratio; v m is the current vehicle speed measured by the integrated navigation, unit: m / s; r is the wheel radius, unit: m; L is the front and rear wheelbase of the six-wheel rear-wheel drive unmanned support vehicle, unit: mm; W is the left and right wheel track of the six-wheel rear-wheel drive unmanned support vehicle, unit: mm; λ is the steering angle coefficient; α m is the steering angle (which refers to the angle between the perpendicular line of the instantaneous speed of the integrated navigation system and the front axle, and can be referred to Figure 1 ); a is the horizontal distance from the measurement point of the integrated navigation system to the center axis, unit: mm; b is the vertical distance from the measurement point of the integrated navigation system to the rear axle, unit: mm;

[0073] The angular velocity of the right drive wheel is calculated by the following formula:

[0074]

[0075] In the formula, ω r is the angular velocity of the right drive wheel, unit: rad / s; s is the corrected slip ratio; v m$v$ is the current vehicle speed measured by integrated navigation, unit: m / s; $r$ is the wheel radius, unit: m; $L$ is the front and rear wheelbase of the six-wheel rear-wheel drive unmanned support vehicle, unit: mm; $W$ is the left and right wheel track of the six-wheel rear-wheel drive unmanned support vehicle, unit: mm; $\lambda$ is the steering angle coefficient; $\alpha$ m is the steering angle; $a$ is the horizontal distance from the measurement point of the integrated navigation system to the central axis, unit: mm; $b$ is the vertical distance from the measurement point of the integrated navigation system to the rear axle, unit: mm.

[0076] If the vehicle receives a right turn command, the angular velocity of the left driving wheel is calculated by the following formula:

[0077]

[0078] In the formula, $\omega$ l is the angular velocity of the left driving wheel, unit: rad / s; $s$ is the corrected slip ratio; $v$ m is the current vehicle speed measured by integrated navigation, unit: m / s; $r$ is the wheel radius, unit: m; $L$ is the front and rear wheelbase of the six-wheel rear-wheel drive unmanned support vehicle, unit: mm; $W$ is the left and right wheel track of the six-wheel rear-wheel drive unmanned support vehicle, unit: mm; $\lambda$ is the steering angle coefficient; $\alpha$ m is the steering angle; $a$ is the horizontal distance from the measurement point of the integrated navigation system to the central axis, unit: mm; $b$ is the vertical distance from the measurement point of the integrated navigation system to the rear axle, unit: mm.

[0079] The angular velocity of the right driving wheel is calculated by the following formula:

[0080]

[0081] In the formula, $\omega$ r is the angular velocity of the right driving wheel, unit: rad / s; $s$ is the corrected slip ratio; $v$ m is the current vehicle speed measured by integrated navigation, unit: m / s; $r$ is the wheel radius, unit: m; $L$ is the front and rear wheelbase of the six-wheel rear-wheel drive unmanned support vehicle, unit: mm; $W$ is the left and right wheel track of the six-wheel rear-wheel drive unmanned support vehicle, unit: mm; $\lambda$ is the steering angle coefficient; $\alpha$ m is the steering angle; $a$ is the horizontal distance from the measurement point of the integrated navigation system to the central axis, unit: mm; $b$ is the vertical distance from the measurement point of the integrated navigation system to the rear axle, unit: mm.

[0082] Embodiment:

[0083] For the six-wheel model adopted in this specific embodiment, the front and rear wheelbase $L = 1700$ mm, the left and right wheel track $W = 1530$ mm, the wheel radius $r = 0.31$ mm, the horizontal distance $a$ from the measurement point of the integrated navigation system to the central axis is 470 mm, and the vertical distance $b$ from the measurement point of the integrated navigation system to the rear axle is 255 mm.

[0084] The speed v of the installation point of the integrated navigation system m = 60 km / h (about 16.6 m / s), and the steering angle coefficient λ is taken as 1.2. According to the sensor, the wheel angular velocity ω = 47.7 rad / s. Based on the slip ratio formula, the slip ratio s calculated based on the sensor can be obtained c :

[0085]

[0086] The parameters in the Burckhardt slip ratio model are determined by Table 1.

[0087] Table 1: Statistical table of empirical slip ratios in the Burckhardt slip ratio model

[0088] Pavement type <![CDATA[C1]]> <![CDATA[C2]]> <![CDATA[C3]]> Dry asphalt 1.281 23.98 0.51 Dry cement 1.196 25.16 0.55 Wet asphalt 0.855 33.83 0.34 Wet cement 0.401 33.7 0.11 Snow 0.194 94.14 0.06 Ice 0.04 306.38 0.02

[0089] In this example, the road surface condition is dry asphalt. According to the table, in the Burckhardt slip ratio model, C1 = 1.281, C2 = 23.98, C3 = 0.51. The slip ratio s based on the empirical model can be calculated t The value is

[0090]

[0091] The value of the variable gain G is

[0092] G = 1 + log 10 |0.11 - 0.18| ≈ -0.15

[0093] According to the slip ratio s calculated based on the sensor as described above c , the slip ratio s based on the empirical model t and the variable gain G, the corrected slip ratio s can be calculated

[0094] s = s c + GΔs = 0.11 - 0.15×(0.11 - 0.18) = 12.05%

[0095] The steering angle α m is taken as 10°. When the vehicle receives a left turn command, the angular velocity ω of the left driving wheel l is:

[0096]

[0097] The angular velocity ω of the right driving wheel r is:

[0098]

[0099] The steering angle α mTake 10°. When the vehicle receives a right-turn command, the angular velocity ω of the left driving wheel l is:

[0100]

[0101] The angular velocity ω of the right driving wheel r is:

[0102]

[0103] Although embodiments and drawings of the present invention are disclosed for illustrative purposes, those skilled in the art can understand that various substitutions, changes, and modifications are possible without departing from the spirit of the present invention and the appended claims. Therefore, the scope of the present invention is not limited to the content disclosed in the embodiments and drawings.

Claims

1. A steering control method for a six-wheel rear-wheel drive unmanned support vehicle, characterized in that: The driving mode of the support vehicle is as follows: the four front wheels are driven wheels, and the left and right rear wheels are driving wheels. There is a hub motor on each driving wheel, including the following steps: Step S1: Determine the position information and speed of the installation point of the integrated navigation system on the support vehicle; Step S2: Determine the vehicle steering angle coefficient according to the speed of the installation point of the integrated navigation system, and obtain the wheel angular velocity; Step S3: Calculate the slip ratio calculated based on the sensor during the driving process according to the wheel angular velocity and the speed of the installation point of the navigation system; Step S4: Determine the parameters in the Burckhardt slip ratio model according to the type of the road surface on which the vehicle is driving, and obtain the slip ratio based on the empirical model during the driving process; Step S5: Integrate the slip ratio calculated based on the sensor and the slip ratio based on the empirical model to obtain the corrected slip ratio; Step S6: Determine whether the currently corrected slip ratio meets the steering requirements; if the slip ratio is lower than 0.9, proceed to the next step; if the slip ratio is higher than 0.9, send a braking command to the left and right hub motors; Step S7: Calculate the steering target angular velocity of the left and right driving wheels according to the vehicle steering command.

2. The steering control method of the six-wheel rear-wheel drive unmanned security vehicle according to claim 1, characterized in that: The position information to be determined in Step S1 is: the horizontal distance a from the measuring point of the integrated navigation system to the central axis and the vertical distance b from the rear axis.

3. The steering control method of the six-wheel rear-wheel drive unmanned security vehicle according to claim 1, characterized in that: The method for determining the vehicle steering angle coefficient in step S2 is as follows: If the current vehicle speed v measured by the integrated navigation m is less than 80 km / h, the steering angle coefficient λ takes a value of 1.2; if the current vehicle speed v measured by the integrated navigation m is greater than or equal to 80 km / h, the steering angle coefficient λ takes a value of 0.

8.

4. The steering control method of the six-wheel rear-wheel drive unmanned support vehicle according to claim 1, wherein: The slip ratio of the vehicle in Step S3 is determined by the following formula: where s c is the slip ratio calculated based on the sensor; v m is the current vehicle speed measured by the integrated navigation, unit: m / s; ω is the wheel angular velocity, unit: rad / s; r is the wheel radius, unit: m.

5. The steering control method of the six-wheel rear-wheel drive unmanned security vehicle according to claim 4, characterized in that: The Burckhardt slip ratio model in Step S4 is: where C1, C2, and C3 are fitting parameters; μ is the peak road surface adhesion coefficient; s t is the slip ratio based on the empirical model; The slip ratio based on the empirical model is obtained by the following formula: where C1, C2, and C3 are fitting parameters; s t is the slip ratio based on the empirical model.

6. The steering control method of the six-wheel rear-wheel drive unmanned security vehicle according to claim 5, wherein: The correction method of the slip ratio in Step S5 is: s = s c + GΔs Where s is the corrected slip ratio; s c is the slip ratio calculated based on the sensor; s t is the slip ratio based on the empirical model; Δs = s c - s t , which is the difference between the slip ratio calculated based on the sensor and the slip ratio calculated based on the empirical model; G is a variable gain; G is a functional expression with respect to |Δs| and changes with the change of |Δs|; the specific expression is: G = 1 + log 10 |Δs| where G is a variable gain; |Δs| = |s c - s t |, which is the absolute value of the difference between the slip ratio calculated based on the sensor and the slip ratio calculated based on the empirical model.

7. The steering control method of the six-wheel rear-wheel drive unmanned security vehicle according to claim 6, characterized in that: In Step S7, if the vehicle receives a left turn command, the angular velocity of the left driving wheel is calculated by the following formula: where ω l is the angular velocity of the left driving wheel, unit: rad / s; s is the corrected slip ratio; v m is the current vehicle speed measured by the integrated navigation, unit: m / s; r is the wheel radius, unit: m; L is the front and rear wheelbase of the six-wheel rear-wheel drive unmanned support vehicle, unit: mm; W is the left and right wheel track of the six-wheel rear-wheel drive unmanned support vehicle, unit: mm; λ is the steering angle coefficient; α m is the steering angle; a is the horizontal distance from the measurement point of the integrated navigation system to the central axis, unit: mm; b is the vertical distance from the measurement point of the integrated navigation system to the rear axle, unit: mm; The angular velocity of the right driving wheel is calculated by the following formula: where ω r is the angular velocity of the right drive wheel, unit: rad / s; s is the corrected slip ratio; v m is the current vehicle speed measured by the integrated navigation, unit: m / s; r is the wheel radius, unit: m; L is the front and rear wheelbase of the six-wheel rear-wheel drive unmanned support vehicle, unit: mm; W is the left and right wheel track of the six-wheel rear-wheel drive unmanned support vehicle, unit: mm; λ is the steering angle coefficient; α m is the steering angle; a is the horizontal distance from the measurement point of the integrated navigation system to the central axis, unit: mm; b is the vertical distance from the measurement point of the integrated navigation system to the rear axle, unit: mm; If the vehicle receives a right turn command, the angular velocity of the left driving wheel is calculated by the following formula: where ω l is the angular velocity of the left driving wheel, unit: rad / s; s is the corrected slip ratio; v m is the current vehicle speed measured by the integrated navigation, unit: m / s; r is the wheel radius, unit: m; L is the front-rear wheelbase of the six-wheel rear-wheel drive unmanned support vehicle, unit: mm; W is the left-right wheel track of the six-wheel rear-wheel drive unmanned support vehicle, unit: mm; λ is the steering angle coefficient; α m is the steering angle; a is the horizontal distance from the measurement point of the integrated navigation system to the central axis, unit: mm; b is the vertical distance from the measurement point of the integrated navigation system to the rear axle, unit: mm; The angular velocity of the right driving wheel is calculated by the following formula: where ω r is the angular velocity of the right drive wheel, unit: rad / s; s is the corrected slip ratio; v m is the current vehicle speed measured by the integrated navigation, unit: m / s; r is the wheel radius, unit: m; L is the front and rear wheelbase of the six-wheel rear-wheel drive unmanned support vehicle, unit: mm; W is the left and right wheel track of the six-wheel rear-wheel drive unmanned support vehicle, unit: mm; λ is the steering angle coefficient; α m is the steering angle; a is the horizontal distance from the measurement point of the integrated navigation system to the central axis, unit: mm; b is the vertical distance from the measurement point of the integrated navigation system to the rear axle, unit: mm.

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