A cooperative control system suitable for preventing folding of a semitrailer

Abstract

The application discloses a kind of suitable for semi-trailer anti-folding cooperative control system;The suitable for semi-trailer anti-folding cooperative control system includes anti-folding prediction module, anti-folding decision module, anti-folding control module, anti-folding cooperative execution module;Through the determination of the driving environment and the state of vehicle itself, the planning of control strategy, the cooperative control of driving, differential braking, active steering is reasonably and effectively carried out;Solve the problem that semi-trailer is out of control due to its high gravity center, large mass, obvious rear amplification effect, prone to severe shimmy under some external force interference or improper operation of driver, resulting in folding and other adverse conditions.The application aims to solve the problem of semi-trailer instability folding by cooperative control of driving, braking and steering mode, and improve the stability of semi-trailer driving.

Description

Technical fields:

[0001] This patent relates to the field of anti-folding control for semi-trailers, specifically to a collaborative control system for anti-folding of semi-trailers based on speed and folding angle. Background technology:

[0002] With economic and social development, e-commerce has experienced rapid growth, which has also spurred the rapid development of the logistics and transportation industry. The express delivery industry's demand for semi-trailers has further increased. However, as the number of semi-trailers on the road increases year by year, the resulting folding hazard has become increasingly serious. Semi-trailers are characterized by a high center of gravity, large weight and volume, and a narrow wheelbase relative to their height. Due to the coupling effect between the tractor and trailer, they have a rear-mounted amplification characteristic. Limited by these characteristics, semi-trailers are prone to folding hazards under conditions such as emergency obstacle avoidance, sudden acceleration or braking on curves, high-speed turns, and varying road surface adhesion coefficients, load conditions, and other unforeseen circumstances.

[0003] With trunk logistics becoming increasingly important and sophisticated, it is imperative to pay more attention to the shortcomings of semi-trailers in cargo transportation, reduce the possibility of folding hazards, and ensure the safety of heavy vehicles and the safety of personnel and property. Summary of the Invention:

[0004] To address the aforementioned problems, this invention provides a collaborative control system for preventing semi-trailers from folding. By acquiring information about the vehicle and the road environment, it enables collaborative control between the tractor and the semi-trailer, reducing the likelihood of folding hazards.

[0005] To achieve the above objectives, the specific technical solution of the present invention is as follows:

[0006] A collaborative control system for preventing folding in semi-trailers includes an anti-folding prediction module, an anti-folding decision module, an anti-folding control module, and an anti-folding collaborative execution module.

[0007] The anti-folding prediction module described in the technical solution includes an environmental monitoring submodule and a vehicle driving submodule. The environmental monitoring submodule is used to monitor the road environment during driving, including road surface condition monitoring and road vehicle monitoring functions. The road surface condition monitoring function is used to obtain information on road adhesion coefficient, road surface slope, and road surface curvature. The road vehicle monitoring function is used to obtain information on the speed of adjacent vehicles and the distance between vehicles in front and behind. The vehicle driving submodule includes a vehicle body sway state monitoring function and a folding angle monitoring function. The vehicle body sway state monitoring function uses onboard sensors to collect parameters such as vehicle speed, yaw rate, and lateral acceleration to determine the degree of vehicle sway. The folding angle monitoring function obtains information on the folding angle through sensors at the articulation point between the tractor and trailer.

[0008] The anti-folding control module in the technical solution receives parameter information measured by the anti-folding prediction module, including vehicle speed, yaw rate, lateral acceleration, road adhesion coefficient, road slope, road curvature, speed of adjacent vehicles, and distance between vehicles. Based on the current vehicle speed, yaw rate, and lateral acceleration, the module designs a body sway weighting coefficient for the trailer body; based on the road adhesion coefficient, road slope, road curvature, speed of adjacent vehicles, and distance between vehicles, the module designs an environmental weighting coefficient; furthermore, the module optimizes the body sway weighting coefficient and environmental weighting coefficient of the trailer body according to the designed calculation formula to determine the folding hazard factor.

[0009] The anti-folding decision module in the technical solution collects information on vehicle speed, yaw rate, lateral acceleration, road adhesion coefficient, road slope, and road curvature. It then uses an environmental weighting coefficient and a trailer body sway weighting coefficient to derive the folding hazard factor. A first discrimination coefficient is used to determine two anti-folding collaborative control modes: one based on folding angle control and the other based on speed control. A second discrimination coefficient is then used to determine whether the anti-folding collaborative execution module performs single control or collaborative control.

[0010] The anti-folding collaborative execution module in the technical solution executes the control strategy determined by the anti-folding control module based on a simplified three-axle model of the semi-trailer. The rear axle of the tractor can perform differential braking and active steering control, while the trailer axle can perform differential braking, active steering, and reverse drive control.

[0011] The anti-folding prediction module in the technical solution determines the vehicle's own and external environmental conditions through the environmental monitoring submodule and the vehicle driving submodule. The collected information includes the current vehicle speed, yaw rate, lateral acceleration, folding angle, road adhesion coefficient, road slope, road curvature, speed of adjacent vehicles, and distance between vehicles in front and behind. The environmental weight coefficient and the trailer body sway weight coefficient are designed using a fuzzy control method. The steps for determining the folding hazard factor are as follows.

[0012] Step 1: The formula for calculating the limit of lateral acceleration is as follows:

[0013]

[0014] Where a y For lateral acceleration, a ymax ε is the lateral acceleration limit value, and ε is the lateral limit coefficient;

[0015] Step 2: The formula for calculating the limit value of yaw rate is as follows:

[0016] r = a y / u

[0017]

[0018] Where r, r max These are the yaw rate and the yaw rate limit of the vehicle during its current movement, respectively, where u is the vehicle speed and ρ is the yaw limit coefficient.

[0019] Step 3: The calculation method for the folding angle threshold is as follows:

[0020]

[0021] Where θ is the folding angle, θ max l is the folding angle threshold value. q It is the longitudinal length of the trailer, l g l0 is the longitudinal length of the tractor unit, and l0 is the wheelbase of the trailer axle.

[0022] Step 4: Optimization analysis is performed using environmental weighting coefficients and vehicle body shimmy weighting coefficients. The method for calculating the first difference coefficient is as follows:

[0023]

[0024] Wherein, N1 is the first distinguishing coefficient, used to distinguish between an anti-folding cooperative control mode based on folding angle control and an anti-folding cooperative control mode based on speed control; a y a ymax These are the lateral acceleration and the lateral acceleration limit of the vehicle during its current movement; r, r max These represent the yaw rate and the yaw rate limit of the vehicle during its current movement; θ represents the current folding angle, θ max The folding angle threshold is denoted by n1 and n2, which are the vehicle body sway weighting coefficient and environmental weighting coefficient, respectively.

[0025] Step 5: Use the known first difference coefficient to distinguish between an anti-folding cooperative control mode based on folding angle control and an anti-folding cooperative control mode based on speed control;

[0026] a) If N1≥1, select an anti-folding cooperative control mode based on speed control;

[0027] b) If 0≤N1<1, select an anti-folding cooperative control mode based on folding angle control;

[0028] Step 6: Calculate the folding hazard factor. The calculation method is as follows:

[0029]

[0030] Where Y0 is the folding hazard factor, u is the current vehicle speed, and u is the folding hazard factor. maxThis is the current speed limit.

[0031] u max The method for determining it is as follows:

[0032] If operating at low speed, u max It is 30km / h;

[0033] If it is a medium-speed operating condition, u max It is 60km / h;

[0034] If it is a high-speed operating condition, u max It is 90km / h;

[0035] Step 7: Determine the judgment parameters based on the folding hazard factors, and determine the driving conditions at this time;

[0036] a) If Y0≥2, let Z t =1, at this point it is determined to be a dangerous working condition;

[0037] b) If 0 ≤ Y0 < 2, let Z t =0, this condition is considered a safe operating condition;

[0038] Z t For determination parameters;

[0039] Step 8: The method for determining the weighting coefficients n1 and n2 for the trailer body sway is fuzzy control, and the specific implementation method is as follows:

[0040] The fuzzy control method takes as input current vehicle speed, yaw rate, lateral acceleration, folding angle, road adhesion coefficient, road surface slope, road surface curvature, adjacent vehicle speed, and distance to vehicles in front and behind as its fuzzy control subset. Its fuzzy control subset is defined as u = {ZE, PO, PS, PM, PB}, i.e., {zero, positive, positive small, positive middle, positive large}, r = {ZE, PO, PS, PM, PB}, i.e., {zero, positive, positive small, positive middle, positive large}, a y ={ZE,PO,PS,PM,PB}, which is {zero, positive, positive small, positive medium, positive large}, θ = {ZE,PO,PS,PM,PB}, which is {zero, positive, positive small, positive medium, positive large}. That is, {zero, positive, positive small, positive medium, positive large}, i = {ZE, PO, PS, PM, PB}, i.e., {zero, positive, positive small, positive medium, positive large}, R = {ZE, PO, PS, PM, PB}, i.e., {zero, positive, positive small, positive medium, positive large}, u p={ZE,PO,PS,PM,PB}, i.e., {zero, positive, positive small, positive medium, positive large}, S = {ZE,PO,PS,PM,PB}, i.e., {zero, positive, positive small, positive medium, positive large}, the output is the vehicle body yaw weighting coefficient n1 = {ZE,PO,PS,PM,PB}, i.e., {zero, positive, positive small, positive medium, positive large}, the environmental weighting coefficient n2 = {ZE,PO,PS,PM,PB}, i.e., {zero, positive, positive small, positive medium, positive large}; where u is the current vehicle speed, r is the yaw rate, a y Let θ be the lateral acceleration and θ be the folding angle. Where i is the road adhesion coefficient, R is the road surface slope, and u is the road surface curvature. p S represents the speed of the vehicle next to it, and S represents the distance between the vehicles in front and behind.

[0041] The anti-folding prediction module in the technical solution distinguishes between an anti-folding cooperative control mode based on folding angle control and an anti-folding cooperative control mode based on speed control using a first discrimination coefficient. The anti-folding decision module then uses a second discrimination coefficient and folding hazard factors to determine whether to implement single control or cooperative control. The determination steps are as follows:

[0042] Step 1: Calculate the second discrepancy coefficient

[0043] N2 = n3Y0 + n4N1

[0044] If N2≥1, then cooperative control is executed;

[0045] If 0 ≤ N2 < 1, then single control is executed;

[0046] Wherein, N2 is the second distinguishing coefficient, Y0 is the folding hazard factor, N1 is the first distinguishing coefficient, n3 is the folding hazard weighting coefficient, and n4 is the distinguishing weighting coefficient;

[0047] Step 2: The method for determining the folding hazard weight coefficient n3 and the differentiation weight coefficient n4 adopts fuzzy control, and the specific implementation method is as follows:

[0048] The fuzzy control method takes the current folding hazard factor and the first distinguishing coefficient as inputs. Its fuzzy control subset is defined as Y0 = {ZE, PO, PS, PM, PB}, i.e. {zero, positive, positive small, positive medium, positive large}, N1 = {ZE, PO, PS, PM, PB}, i.e. {zero, positive, positive small, positive medium, positive large}, and the output is the folding hazard weight coefficient n3 = {ZE, PO, PS, PM, PB}, i.e. {zero, positive, positive small, positive medium, positive large}, and the distinguishing weight coefficient n4 = {ZE, PO, PS, PM, PB}, i.e. {zero, positive, positive small, positive medium, positive large}.

[0049] Step 3: The specific steps for the anti-folding decision module to select the required execution mode for the anti-folding collaborative execution module based on the second difference coefficient are as follows:

[0050] When N1≥1, select an anti-folding cooperative control mode based on speed control;

[0051] 1) If u≤30km / h and 0≤Y0<2, it is determined to be a safe working condition. At the same time, 0≤N2<1, single control is executed, and the anti-folding collaborative execution module executes single control of trailer axle reverse drive.

[0052] 2) If 30km / h<u≤60km / h and Y0≥2, it is judged as a dangerous working condition. At the same time, N2≥1, the cooperative control is executed. The anti-folding cooperative execution module executes the differential braking of the rear axle of the tractor and simultaneously controls the cooperative control to make the braking forces of the wheels on both sides of the trailer axle equal.

[0053] 3) If u>60km / h and Y0≥2, it is judged as a dangerous working condition. At the same time, N2≥1, the cooperative control is executed. The anti-folding cooperative execution module executes the active steering of the rear axle of the tractor and simultaneously controls the cooperative control to make the braking force of the wheels on both sides of the trailer axle equal.

[0054] When 0≤N1<1, select an anti-folding cooperative control mode based on folding angle control;

[0055] 1) If 120°≤θ≤150° and 0≤Y0<2, it is determined to be a safe working condition. At the same time, 0≤N2<1, single control is executed, and the anti-folding collaborative execution module executes single control of trailer axle reverse drive.

[0056] 2) If 90°≤θ<120° and 0≤Y0<2, it is determined to be a safe working condition. At the same time, 0≤N2<1, single control is executed, and the anti-folding collaborative execution module executes single control of trailer axle differential braking.

[0057] 3) If 30°≤θ<90° and Y0≥2, it is judged as a dangerous working condition. At the same time, N2≥1, the collaborative control is executed. The anti-folding collaborative execution module executes the active steering of the rear axle of the tractor and controls the collaborative control to make the braking force of the wheels on both sides of the trailer axle equal.

[0058] The anti-folding control module described in the technical solution calculates the rear wheel steering angle of the tractor's rear wheels for active steering based on the parameter information received from the anti-folding prediction module. The calculation method is as follows:

[0059] Step 1: When this anti-folding collaborative execution module performs active steering of the tractor's rear axle.

[0060]

[0061] Where Δα is the instantaneous increment of the rear wheel steering angle, L xV is the offset of the trailer axle from the rear axle of the tractor. y The longitudinal acceleration of the vehicle is denoted by T, and the data acquisition time is denoted by T.

[0062] Step 2: Optimize PID parameters for the estimated instantaneous increment of the rear wheel steering angle.

[0063] PID control gain function:

[0064] Step 3: α = α0 + Δα

[0065] Where α is the actual active steering angle of the rear wheel, Δα is the instantaneous increment of the rear wheel steering angle, and α0 is the rear wheel steering angle at the previous moment;

[0066] Step 4: The calculation process for the limit steering angle in the active steering system is as follows:

[0067] When the vehicle is under active steering control, the calculation of the changing lateral acceleration is as follows:

[0068] a yn =a y0 +Δa y

[0069] a) At this point, a limiting factor μ is introduced.

[0070] ①a ynmax =a y0 +μΔa y

[0071] ②a ynmin =a y0 -μΔa y

[0072] b) Introduce adjustment coefficient k t

[0073] ①α max =|k t a ynmax +α0|

[0074] ②α min =|k t a ynmax -α0|

[0075] Where a yn a is the lateral acceleration when the vehicle performs active steering control. y0 The initial lateral acceleration is Δa. y

[0076] a represents the change in lateral acceleration during active steering. ynmax a is the maximum value of the lateral acceleration variation limit. ynminFor the minimum limit of lateral acceleration variation, α max α is the maximum limit of the rear wheel steering angle. min This is the minimum limit of the rear wheel steering angle.

[0077] The anti-folding control module described in the technical solution calculates the additional yaw moment required by the differential braking control strategy in the anti-folding cooperative execution module by receiving parameter information from the anti-folding prediction module, and calculates the distribution of braking force based on the additional yaw moment.

[0078] Step 1: Analysis of the additional torque situation is as follows:

[0079] We will only discuss understeer and oversteer:

[0080] If the vehicle understeers when turning left at this time, it is necessary to compensate for the yaw moment by turning to the left of the vehicle.

[0081] 2) If oversteering occurs, the yaw moment needs to be compensated to the right of the vehicle;

[0082] If the vehicle understeers when turning right at this time, it is necessary to compensate for the yaw moment to the right of the vehicle.

[0083] 2) If oversteering occurs, the yaw moment needs to be compensated by moving the vehicle to the left.

[0084] Planning for additional yaw moment based on steering characteristics;

[0085] Step 2: The calculation of braking torque distribution is as follows:

[0086] 1) Braking torque of the front axle wheels of the tractor:

[0087]

[0088]

[0089] 2) Braking torque of the rear axle wheels of the tractor:

[0090]

[0091]

[0092] 3) Braking torque of trailer axle wheels:

[0093]

[0094]

[0095] Among them, T l1 For the torque of the left wheel of the front axle of the tractor, T l2d1 is the right wheel torque of the tractor's front axle, d2 is the left wheel angle stability coefficient of the tractor's front axle, l1 is the track width of the tractor's front axle, r1 is the tire radius of the tractor's front axle, and T is the torque of the right wheel of the tractor's front axle. la1 Braking torque of the left wheel of the front axle of the tractor, T la2 Braking torque of the right wheel of the front axle of the tractor, T q1 Torque of the left wheel of the tractor's rear axle, T q2 The torque of the right wheel of the tractor's rear axle, d3 is the stability coefficient of the left wheel angle of the tractor's rear axle, d4 is the stability coefficient of the right wheel angle of the tractor's rear axle, l2 is the track width of the tractor's rear axle, r2 is the tire radius of the tractor's rear axle, and T is the torque of the right wheel of the tractor's rear axle. lb1 Braking torque of the left wheel of the rear axle of the tractor, T lb2 Braking torque of the right wheel of the tractor's rear axle, T g1 Trailer axle left wheel torque, T g2 The right wheel torque of the trailer axle, d5 is the left wheel angle stability coefficient of the trailer axle, d6 is the right wheel angle stability coefficient of the trailer axle, l3 is the track width of the trailer axle, r3 is the tire radius of the trailer axle, T lc1 Trailer axle left wheel braking torque, T lc2 Braking torque of the right wheel of the trailer axle.

[0096] The anti-folding collaborative execution module described in the technical solution can use the reverse driving torque of the trailer axle to increase the folding angle of the folded semi-trailer. This reverse drive control can be started autonomously under safe working conditions.

[0097] When 0≤Y0<2, it is determined to be a safe operating condition;

[0098] If u≤30km / h and 120°≤θ≤150°, the reverse drive torque will pull the semi-trailer to a folding angle greater than 150°, at which point the reverse drive control will automatically shut off.

[0099] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0100] By acquiring environmental and current vehicle driving information, a first differentiation coefficient is calculated to differentiate and control anti-folding from two aspects: speed and folding angle. Furthermore, a second differentiation coefficient is calculated to execute coordinated control of rear wheel active steering, differential braking, and reverse drive, which is beneficial to improving the stability of semi-trailer driving and reducing the harm of folding hazards. Attached image description:

[0101] The invention will now be further described with reference to the accompanying drawings.

[0102] Figure 1 This is a flowchart of the proposed anti-folding collaborative control system.

[0103] Figure 2 It is a simplified three-axle model of a semi-trailer.

[0104] The names of the reference numerals in the accompanying drawings of this invention are: 1-front axle of the tractor, 2-rear axle of the tractor, 3-trailer axle. Detailed implementation method:

[0105] like Figure 1 As shown, the entire system includes an anti-folding prediction module, an anti-folding decision module, an anti-folding control module, and an anti-folding collaborative execution module. The anti-folding prediction module includes an environmental monitoring submodule and a vehicle driving submodule. The environmental monitoring submodule monitors the road environment during driving, including road surface condition monitoring and road vehicle monitoring functions. The road surface condition monitoring function acquires information on road adhesion coefficient, road slope, and road curvature. The road vehicle monitoring function acquires information on the speed of adjacent vehicles and the distance between vehicles. The vehicle driving submodule includes a vehicle body sway monitoring function and a folding angle monitoring function. The vehicle body sway monitoring function uses onboard sensors to collect parameters such as vehicle speed, yaw rate, and lateral acceleration to determine the degree of vehicle sway. The folding angle monitoring function acquires folding angle information through sensors at the articulation point between the tractor and trailer.

[0106] The anti-folding control module receives parameter information measured by the anti-folding prediction module, including vehicle speed, yaw rate, lateral acceleration, road adhesion coefficient, road slope, road curvature, speed of adjacent vehicles, and distance between vehicles. Based on the current vehicle speed, yaw rate, and lateral acceleration, it designs the trailer body sway weight coefficient; based on the road adhesion coefficient, road slope, road curvature, speed of adjacent vehicles, and distance between vehicles, it designs the environmental weight coefficient; furthermore, it optimizes the trailer body sway weight coefficient and environmental weight coefficient according to the designed calculation formula to determine the folding hazard factor.

[0107] The anti-folding decision module collects information on vehicle speed, yaw rate, lateral acceleration, road adhesion coefficient, road slope, and road curvature. It also uses environmental weighting coefficients and trailer body sway weighting coefficients to derive folding hazard factors. Using a first discrimination coefficient, it determines two anti-folding collaborative control modes: one based on folding angle control and the other based on speed control. Furthermore, it uses a second discrimination coefficient to determine whether the anti-folding collaborative execution module performs single control or collaborative control.

[0108] like Figure 2 The anti-folding collaborative execution module shown executes the control strategy determined by the anti-folding control module based on a simplified three-axle model of the semi-trailer. The rear axle of the tractor can perform differential braking and active steering control, while the trailer axle can perform differential braking, active steering, and reverse drive control.

[0109] The anti-folding prediction module determines the vehicle's own and external environmental conditions through the environmental monitoring submodule and the vehicle driving submodule. The collected information includes the current vehicle speed, yaw rate, lateral acceleration, folding angle, road adhesion coefficient, road slope, road curvature, speed of adjacent vehicles, and distance between vehicles in front and behind. The environmental weight coefficient and the trailer body sway weight coefficient are designed using fuzzy control. The steps for determining the folding hazard factor are as follows.

[0110] Step 1: The formula for calculating the limit of lateral acceleration is as follows:

[0111]

[0112] Where a y For lateral acceleration, a ymax ε is the limit value of lateral acceleration, and ε is the lateral limit coefficient;

[0113] Step 2: The formula for calculating the limit value of yaw rate is as follows:

[0114] r = a y / u

[0115]

[0116] Where r, r max These are the yaw rate and the yaw rate limit of the vehicle during its current movement, respectively, where u is the vehicle speed and ρ is the yaw limit coefficient.

[0117] Step 3: The calculation method for the folding angle threshold is as follows:

[0118]

[0119] Where θ is the folding angle, θ max l is the folding angle threshold value. q It is the longitudinal length of the trailer, l g l0 is the longitudinal length of the tractor unit, and l0 is the wheelbase of the trailer axle.

[0120] Step 4: Optimization analysis is performed using environmental weighting coefficients and vehicle body shimmy weighting coefficients. The method for calculating the first difference coefficient is as follows:

[0121]

[0122] Wherein, N1 is the first distinguishing coefficient, used to distinguish between an anti-folding cooperative control mode based on folding angle control and an anti-folding cooperative control mode based on speed control; a y a ymax These are the lateral acceleration and the lateral acceleration limit of the vehicle during its current movement; r, r maxThese represent the yaw rate and the yaw rate limit of the vehicle during its current movement; θ represents the current folding angle, θ max The folding angle threshold is denoted by n1 and n2, which are the vehicle body sway weighting coefficient and environmental weighting coefficient, respectively.

[0123] Step 5: Use the known first difference coefficient to distinguish between an anti-folding cooperative control mode based on folding angle control and an anti-folding cooperative control mode based on speed control;

[0124] a) If N1≥1, select an anti-folding cooperative control mode based on speed control;

[0125] b) If 0≤N1<1, select an anti-folding cooperative control mode based on folding angle control;

[0126] Step 6: Calculate the folding hazard factor. The calculation method is as follows:

[0127]

[0128] Where Y0 is the folding hazard factor, u is the current vehicle speed, and u is the folding hazard factor. max This is the current speed limit.

[0129] u max The method for determining it is as follows:

[0130] If operating at low speed, u max It is 30km / h;

[0131] If it is a medium-speed operating condition, u max It is 60km / h;

[0132] If it is a high-speed operating condition, u max It is 90km / h;

[0133] Step 7: Determine the judgment parameters based on the folding hazard factors, and determine the driving conditions at this time;

[0134] a) If Y0≥2, let Z t =1, at this point it is determined to be a dangerous working condition;

[0135] b) If 0 ≤ Y0 < 2, let Z t =0, this condition is considered a safe operating condition;

[0136] Z t For determination parameters;

[0137] Step 8: The method for determining the weighting coefficients n1 and n2 for the trailer body sway is fuzzy control. The specific implementation method is as follows:

[0138] The fuzzy control method takes as input current vehicle speed, yaw rate, lateral acceleration, folding angle, road adhesion coefficient, road surface slope, road surface curvature, adjacent vehicle speed, and distance to vehicles in front and behind as its fuzzy control subset. Its fuzzy control subset is defined as u = {ZE, PO, PS, PM, PB}, i.e., {zero, positive, positive small, positive middle, positive large}, r = {ZE, PO, PS, PM, PB}, i.e., {zero, positive, positive small, positive middle, positive large}, a y ={ZE,PO,PS,PM,PB}, which is {zero, positive, positive small, positive medium, positive large}, θ = {ZE,PO,PS,PM,PB}, which is {zero, positive, positive small, positive medium, positive large}. That is, {zero, positive, positive small, positive medium, positive large}, i = {ZE, PO, PS, PM, PB}, i.e., {zero, positive, positive small, positive medium, positive large}, R = {ZE, PO, PS, PM, PB}, i.e., {zero, positive, positive small, positive medium, positive large}, u p ={ZE,PO,PS,PM,PB}, i.e., {zero, positive, positive small, positive medium, positive large}, S = {ZE,PO,PS,PM,PB}, i.e., {zero, positive, positive small, positive medium, positive large}, the output is the vehicle body yaw weighting coefficient n1 = {ZE,PO,PS,PM,PB}, i.e., {zero, positive, positive small, positive medium, positive large}, the environmental weighting coefficient n2 = {ZE,PO,PS,PM,PB}, i.e., {zero, positive, positive small, positive medium, positive large}; where u is the current vehicle speed, r is the yaw rate, a y Let θ be the lateral acceleration and θ be the folding angle. Where i is the road adhesion coefficient, R is the road surface slope, and u is the road surface curvature. p S represents the speed of the vehicle next to it, and S represents the distance between the vehicles in front and behind.

[0139] After the anti-folding prediction module distinguishes between an anti-folding cooperative control mode based on folding angle control and an anti-folding cooperative control mode based on speed control using a first discrimination coefficient, the anti-folding decision module uses a second discrimination coefficient and folding hazard factors to determine whether to implement single control or cooperative control. The determination steps are as follows:

[0140] Step 1: Calculate the second discrepancy coefficient

[0141] N2 = n3Y0 + n4N1

[0142] If N2≥1, then cooperative control is executed;

[0143] If 0 ≤ N2 < 1, then single control is executed;

[0144] Wherein, N2 is the second distinguishing coefficient, Y0 is the folding hazard factor, N1 is the first distinguishing coefficient, n3 is the folding hazard weighting coefficient, and n4 is the distinguishing weighting coefficient;

[0145] Step 2: The method for determining the folding hazard weight coefficient n3 and the differentiation weight coefficient n4 adopts fuzzy control, and the specific implementation method is as follows:

[0146] The fuzzy control method takes the current folding hazard factor and the first distinguishing coefficient as inputs. Its fuzzy control subset is defined as Y0 = {ZE, PO, PS, PM, PB}, i.e. {zero, positive, positive small, positive medium, positive large}, N1 = {ZE, PO, PS, PM, PB}, i.e. {zero, positive, positive small, positive medium, positive large}, and the output is the folding hazard weight coefficient n3 = {ZE, PO, PS, PM, PB}, i.e. {zero, positive, positive small, positive medium, positive large}, and the distinguishing weight coefficient n4 = {ZE, PO, PS, PM, PB}, i.e. {zero, positive, positive small, positive medium, positive large}.

[0147] Step 3: The specific steps for the anti-folding decision module to select the required execution mode for the anti-folding collaborative execution module based on the second difference coefficient are as follows:

[0148] When N1≥1, select an anti-folding cooperative control mode based on speed control;

[0149] 1) If u≤30km / h and 0≤Y0<2, it is determined to be a safe working condition. At the same time, 0≤N2<1, single control is executed, and the anti-folding collaborative execution module executes single control of trailer axle reverse drive.

[0150] 2) If 30km / h<u≤60km / h and Y0≥2, it is judged as a dangerous working condition. At the same time, N2≥1, the cooperative control is executed. The anti-folding cooperative execution module executes the differential braking of the rear axle of the tractor and simultaneously controls the cooperative control to make the braking forces of the wheels on both sides of the trailer axle equal.

[0151] 3) If u>60km / h and Y0≥2, it is judged as a dangerous working condition. At the same time, N2≥1, the cooperative control is executed. The anti-folding cooperative execution module executes the active steering of the rear axle of the tractor and simultaneously controls the cooperative control to make the braking force of the wheels on both sides of the trailer axle equal.

[0152] When 0≤N1<1, select an anti-folding cooperative control mode based on folding angle control;

[0153] 1) If 120°≤θ≤150° and 0≤Y0<2, it is determined to be a safe working condition. At the same time, 0≤N2<1, single control is executed, and the anti-folding collaborative execution module executes single control of trailer axle reverse drive.

[0154] 2) If 90°≤θ<120° and 0≤Y0<2, it is determined to be a safe working condition. At the same time, 0≤N2<1, single control is executed, and the anti-folding collaborative execution module executes single control of trailer axle differential braking.

[0155] 3) If 30°≤θ<90° and Y0≥2, it is judged as a dangerous working condition. At the same time, N2≥1, the collaborative control is executed. The anti-folding collaborative execution module executes the active steering of the rear axle of the tractor and controls the collaborative control to make the braking force of the wheels on both sides of the trailer axle equal.

[0156] The anti-folding control module described in the technical solution calculates the rear wheel steering angle of the tractor's rear wheels for active steering based on the parameter information received from the anti-folding prediction module. The calculation method is as follows:

[0157] Step 1: When this anti-folding collaborative execution module performs active steering of the tractor's rear axle.

[0158]

[0159] Where Δα is the instantaneous increment of the rear wheel steering angle, L x V is the offset of the trailer axle from the rear axle of the tractor. y The longitudinal acceleration of the vehicle is denoted by T, and the data acquisition time is denoted by T.

[0160] Step 2: Optimize PID parameters for the estimated instantaneous increment of the rear wheel steering angle.

[0161] PID control gain function:

[0162] Step 3: α = α0 + Δα

[0163] Where α is the actual active steering angle of the rear wheel, Δα is the instantaneous increment of the rear wheel steering angle, and α0 is the rear wheel steering angle at the previous moment;

[0164] Step 4: The calculation process for the limit steering angle in the active steering system is as follows:

[0165] When the vehicle is under active steering control, the calculation of the changing lateral acceleration is as follows:

[0166] a yn =a y0 +Δa y

[0167] a) At this point, a limiting factor μ is introduced.

[0168] ①a ynmax =a y0 +μΔa y

[0169] ②a ynmin =a y0 -μΔa y

[0170] b) Introduce adjustment coefficient k t

[0171] ①α max =|k t a ynmax +α0|

[0172] ②α min =|k t a ynmax -α0|

[0173] Where a yn a is the lateral acceleration when the vehicle performs active steering control. y0 The initial lateral acceleration is Δa. y

[0174] a represents the change in lateral acceleration during active steering. ynmax a is the maximum value of the lateral acceleration variation limit. ynmin For the minimum limit of lateral acceleration variation, α max α is the maximum limit of the rear wheel steering angle. min This is the minimum limit of the rear wheel steering angle.

[0175] The anti-folding control module calculates the additional yaw moment required by the differential braking control strategy in the anti-folding cooperative execution module by receiving parameter information from the anti-folding prediction module, and calculates the distribution of braking force based on the additional yaw moment.

[0176] Step 1: Analysis of the additional torque situation is as follows:

[0177] We will only discuss understeer and oversteer:

[0178] If the vehicle understeers when turning left at this time, it is necessary to compensate for the yaw moment by turning to the left of the vehicle.

[0179] 2) If oversteering occurs, the yaw moment needs to be compensated to the right of the vehicle;

[0180] If the vehicle understeers when turning right at this time, it is necessary to compensate for the yaw moment to the right of the vehicle.

[0181] 2) If oversteering occurs, the yaw moment needs to be compensated by moving the vehicle to the left.

[0182] Planning for additional yaw moment based on steering characteristics;

[0183] Step 2: The calculation of braking torque distribution is as follows:

[0184] 1) Braking torque of the front axle wheels of the tractor:

[0185]

[0186]

[0187] 2) Braking torque of the rear axle wheels of the tractor:

[0188]

[0189]

[0190] 3) Braking torque of trailer axle wheels:

[0191]

[0192]

[0193] Among them, T l1 For the torque of the left wheel of the front axle of the tractor, T l2 d1 is the right wheel torque of the tractor's front axle, d2 is the left wheel angle stability coefficient of the tractor's front axle, l1 is the track width of the tractor's front axle, r1 is the tire radius of the tractor's front axle, and T is the torque of the right wheel of the tractor's front axle. la1 Braking torque of the left wheel of the front axle of the tractor, T la2 Braking torque of the right wheel of the front axle of the tractor, T q1 Torque of the left wheel of the tractor's rear axle, T q2 The torque of the right wheel of the tractor's rear axle, d3 is the stability coefficient of the left wheel angle of the tractor's rear axle, d4 is the stability coefficient of the right wheel angle of the tractor's rear axle, l2 is the track width of the tractor's rear axle, r2 is the tire radius of the tractor's rear axle, and T is the torque of the right wheel of the tractor's rear axle. lb1 Braking torque of the left wheel of the rear axle of the tractor, T lb2 Braking torque of the right wheel of the tractor's rear axle, T g1 Trailer axle left wheel torque, T g2 The right wheel torque of the trailer axle, d5 is the left wheel angle stability coefficient of the trailer axle, d6 is the right wheel angle stability coefficient of the trailer axle, l3 is the track width of the trailer axle, r3 is the tire radius of the trailer axle, T lc1 Braking torque of the left wheel of the trailer axle, Y lc2 Braking torque of the right wheel of the trailer axle.

[0194] The anti-folding collaborative execution module can use the reverse driving torque of the trailer axle to increase the folding angle of the folded semi-trailer. This reverse drive control can be started autonomously under safe working conditions.

[0195] When 0≤Y0<2, it is determined to be a safe operating condition;

[0196] If u≤30km / h and 120°≤θ≤150°, the reverse drive torque will pull the semi-trailer to a folding angle greater than 150°, at which point the reverse drive control will automatically shut off.

[0197] The foregoing discussion is merely a preferred embodiment of the present invention, intended for explanation and illustration, and is not intended to limit the invention itself. The invention is not limited to the specific embodiments disclosed herein, but is defined by the following claims. Furthermore, the descriptions relating to specific embodiments in the foregoing description should not be construed as limiting the scope of the invention or the definitions of the terms used in the claims. Various other embodiments and variations of the disclosed embodiments will be apparent to those skilled in the art. However, all such embodiments, modifications, and variations that do not depart from the basic concept of the invention are within the scope of the appended claims.

Claims

1. A cooperative control system for preventing folding in semi-trailers, characterized in that: The anti-folding collaborative control system for the semi-trailer includes an anti-folding prediction module, an anti-folding decision module, an anti-folding control module, and an anti-folding collaborative execution module. The anti-folding prediction module includes an environmental monitoring submodule and a vehicle driving submodule. The environmental monitoring submodule is used to monitor the road environment during driving, including road surface condition monitoring function and road vehicle monitoring function. The road surface condition monitoring function is used to obtain information on road adhesion coefficient, road surface slope, and road surface curvature. The road vehicle monitoring function is used to obtain the speed of adjacent vehicles and the distance between vehicles in front and behind. The vehicle driving submodule includes a vehicle body sway monitoring function and a folding angle monitoring function. The vehicle body sway monitoring function collects parameters such as vehicle speed, yaw rate and lateral acceleration of the vehicle through on-board sensors and determines the degree of vehicle sway at this time. The folding angle monitoring function obtains information about the folding angle through sensors at the hinge between the tractor and the trailer. The anti-folding control module receives parameter information measured by the anti-folding prediction module, including vehicle speed, yaw rate, lateral acceleration, road adhesion coefficient, road slope, road curvature, speed of adjacent vehicles, and distance between vehicles. Based on the current vehicle speed, yaw rate, and lateral acceleration, it designs a body sway weighting coefficient for the trailer body; based on the road adhesion coefficient, road slope, road curvature, speed of adjacent vehicles, and distance between vehicles, it designs an environmental weighting coefficient; furthermore, it optimizes the body sway weighting coefficient and environmental weighting coefficient of the trailer body according to the designed calculation formula to determine the folding hazard factor. The anti-folding decision module collects information on vehicle speed, yaw rate, lateral acceleration, road adhesion coefficient, road slope, and road curvature, and uses environmental weight coefficient and trailer body sway weight coefficient to derive folding hazard factors. It also uses the first differentiation coefficient to determine two anti-folding collaborative control modes. One is an anti-folding collaborative control mode based on folding angle control, and the other is an anti-folding collaborative control mode based on speed control; then, the second difference coefficient is used to determine whether the anti-folding collaborative execution module performs single control or collaborative control. The anti-folding collaborative execution module executes the control strategy determined by the anti-folding control module based on a simplified three-axle model of the semi-trailer. The rear axle of the tractor can perform differential braking and active steering control, while the trailer axle can perform differential braking, active steering, and reverse drive control.

2. The collaborative control system for preventing folding of semi-trailers as described in claim 1, characterized in that... The anti-folding prediction module determines the vehicle's own condition and the external environment through the environmental monitoring submodule and the vehicle driving submodule. The collected information includes current vehicle speed, yaw rate, lateral acceleration, folding angle, road adhesion coefficient, road surface slope, road surface curvature, speed of adjacent vehicles, and distance to vehicles in front and behind. A fuzzy control method is used to design the environmental weighting coefficient and the trailer body sway weighting coefficient at this time. The steps for determining the folding hazard factor are as follows: Step 1: The formula for calculating the limit of lateral acceleration is as follows: Where a y For lateral acceleration, a ymax ε is the limit value of lateral acceleration, and ε is the lateral limit coefficient; Step 2: The formula for calculating the limit value of yaw rate is as follows: r=a y / u Where r, r max These are the yaw rate and the yaw rate limit of the vehicle during its current movement, respectively, where u is the vehicle speed and ρ is the yaw limit coefficient. Step 3: The calculation method for the folding angle threshold is as follows: Where θ is the folding angle, θ max l is the folding angle threshold value. q It is the longitudinal length of the trailer, l g l0 is the longitudinal length of the tractor unit, and l0 is the wheelbase of the trailer axle. Step 4: Optimization analysis is performed using environmental weighting coefficients and vehicle body shimmy weighting coefficients. The method for calculating the first difference coefficient is as follows: Wherein, N1 is the first distinguishing coefficient, used to distinguish between an anti-folding cooperative control mode based on folding angle control and an anti-folding cooperative control mode based on speed control; a y a ymax These are the lateral acceleration and the lateral acceleration limit of the vehicle during its current movement; r, r max These represent the yaw rate and the yaw rate limit of the vehicle during its current movement; θ represents the current folding angle, θ max The folding angle threshold is denoted by n1 and n2, which are the vehicle body sway weighting coefficient and environmental weighting coefficient, respectively. Step 5: Using the known first difference coefficient, distinguish between an anti-folding cooperative control mode based on folding angle control and an anti-folding cooperative control mode based on speed control: a) If N1≥1, select an anti-folding cooperative control mode based on speed control; b) If 0≤N1<1, select an anti-folding cooperative control mode based on folding angle control; Step 6: Calculate the folding hazard factor. The calculation method is as follows: Where Y0 is the folding hazard factor, u is the current vehicle speed, and u is the folding hazard factor. max This is the current speed limit. u max The method for determining it is as follows: If operating at low speed, u max It is 30km / h; If it is a medium-speed operating condition, u max It is 60km / h; If it is a high-speed operating condition, u max It is 90km / h; Step 7: Determine the judgment parameters based on the folding hazard factors, and determine the driving conditions at this time; a) If Y0≥2, let Z t =1, at this point it is determined to be a dangerous working condition; b) If 0 ≤ Y0 < 2, let Z t =0, this condition is considered a safe operating condition; Z t For determination parameters; Step 8: The method for determining the weighting coefficients n1 and n2 for the trailer body sway is fuzzy control. The specific implementation method is as follows: The fuzzy control method takes as input current vehicle speed, yaw rate, lateral acceleration, folding angle, road adhesion coefficient, road surface slope, road surface curvature, adjacent vehicle speed, and distance to vehicles in front and behind as its fuzzy control subset. Its fuzzy control subset is defined as u = {ZE, PO, PS, PM, PB}, i.e., {zero, positive, positive small, positive middle, positive large}, r = {ZE, PO, PS, PM, PB}, i.e., {zero, positive, positive small, positive middle, positive large}, a y ={ZE,PO,PS,PM,PB}, which is {zero, positive, positive small, positive medium, positive large}, θ = {ZE,PO,PS,PM,PB}, which is {zero, positive, positive small, positive medium, positive large}. That is, {zero, positive, positive small, positive medium, positive large}, i = {ZE, PO, PS, PM, PB}, i.e., {zero, positive, positive small, positive medium, positive large}, R = {ZE, PO, PS, PM, PB}, i.e., {zero, positive, positive small, positive medium, positive large}, u p ={ZE,PO,PS,PM,PB}, i.e., {zero, positive, positive small, positive medium, positive large}, S = {ZE,PO,PS,PM,PB}, i.e., {zero, positive, positive small, positive medium, positive large}, the output is the vehicle body yaw weighting coefficient n1 = {ZE,PO,PS,PM,PB}, i.e., {zero, positive, positive small, positive medium, positive large}, the environmental weighting coefficient n2 = {ZE,PO,PS,PM,PB}, i.e., {zero, positive, positive small, positive medium, positive large}; where u is the current vehicle speed, r is the yaw rate, a y Let θ be the lateral acceleration and θ be the folding angle. Where i is the road adhesion coefficient, R is the road surface slope, and u is the road surface curvature. p S represents the speed of the vehicle next to it, and S represents the distance between the vehicles in front and behind.

3. A collaborative control system for preventing folding of semi-trailers as described in claim 1, characterized in that... After the anti-folding prediction module distinguishes between an anti-folding cooperative control mode based on folding angle control and an anti-folding cooperative control mode based on speed control using a first discrimination coefficient, the anti-folding decision module uses a second discrimination coefficient and folding hazard factors to determine whether to implement single control or cooperative control. The determination steps are as follows: Step 1: Calculate the second discrepancy coefficient N2 = n3Y0 + n4N1 If N2≥1, then cooperative control is executed; If 0 ≤ N2 < 1, then single control is executed; Wherein, N2 is the second distinguishing coefficient, Y0 is the folding hazard factor, N1 is the first distinguishing coefficient, n3 is the folding hazard weighting coefficient, and n4 is the distinguishing weighting coefficient; Step 2: The method for determining the folding hazard weight coefficient n3 and the differentiation weight coefficient n4 adopts fuzzy control, and the specific implementation method is as follows: The fuzzy control method takes the current folding hazard factor and the first distinguishing coefficient as inputs. Its fuzzy control subset is defined as Y0 = {ZE, PO, PS, PM, PB}, i.e. {zero, positive, positive small, positive medium, positive large}, N1 = {ZE, PO, PS, PM, PB}, i.e. {zero, positive, positive small, positive medium, positive large}, and the output is the folding hazard weight coefficient n3 = {ZE, PO, PS, PM, PB}, i.e. {zero, positive, positive small, positive medium, positive large}, and the distinguishing weight coefficient n4 = {ZE, PO, PS, PM, PB}, i.e. {zero, positive, positive small, positive medium, positive large}. Step 3: The specific steps for the anti-folding decision module to select the required execution mode for the anti-folding collaborative execution module based on the second difference coefficient are as follows: When N1≥1, select an anti-folding cooperative control mode based on speed control; 1) If u≤30km / h and 0≤Y0<2, it is determined to be a safe operating condition; At the same time, 0≤N2<1, single control is executed, and the anti-folding collaborative execution module executes single control of the trailer axle reverse drive; 2) If 30km / h < u ≤ 60km / h and Y0 ≥ 2, it is judged as a dangerous working condition; At the same time, N2≥1, the coordinated control is executed. The anti-folding coordinated execution module executes the differential braking of the rear axle of the tractor, and at the same time controls the coordinated control to make the braking forces of the wheels on both sides of the trailer axle equal. 3) If u > 60 km / h and Y n ≥2, is judged as a dangerous working condition; At the same time, N2≥1, coordinated control is executed. The anti-folding coordinated execution module executes the active steering of the rear axle of the tractor, and at the same time controls the coordinated control to make the braking force of the wheels on both sides of the trailer axle equal. When 0≤N1<1, select an anti-folding cooperative control mode based on folding angle control; 1) If 120°≤θ≤150° and 0≤Y0<2, it is determined to be a safe working condition; At the same time, 0≤N2<1, single control is executed, and the anti-folding collaborative execution module executes single control of the trailer axle reverse drive; 2) If 90°≤θ<120° and 0≤Y0<2, it is determined to be a safe working condition; At the same time, 0≤N2<1, single control is executed, and the anti-folding collaborative execution module executes single control of the trailer axle differential braking; 3) If 30°≤θ<90° and Y0≥2, it is determined to be a dangerous working condition; At the same time, N2≥1, coordinated control is executed. The anti-folding coordinated control module executes active steering of the rear axle of the tractor and coordinates the control to ensure that the braking force of the wheels on both sides of the trailer axle is equal.

4. A collaborative control system for preventing folding of semi-trailers as described in claim 1, characterized in that... The anti-folding control module calculates the rear wheel steering angle of the tractor's rear wheels for active steering based on the parameter information received from the anti-folding prediction module. The calculation method is as follows: Step 1: When this anti-folding collaborative execution module performs active steering of the tractor's rear axle. Where Δα is the instantaneous increment of the rear wheel steering angle, L x V is the offset of the trailer axle from the rear axle of the tractor. y The longitudinal acceleration of the vehicle is denoted by T, and the data acquisition time is denoted by T. Step 2: Optimize PID parameters for the estimated instantaneous increment of the rear wheel steering angle. PID control gain function: Step 3: α = α0 + Δα Where α is the actual active steering angle of the rear wheel, Δα is the instantaneous increment of the rear wheel steering angle, and α0 is the rear wheel steering angle at the previous moment; Step 4: The calculation process for the limit steering angle in the active steering system is as follows: When the vehicle is under active steering control, the calculation of the changing lateral acceleration is as follows: in yn = yes y0 +Δa y a) At this point, a limiting factor μ is introduced. ①a ynmax =a y0 +μΔa y ②a ynmin =a y0 -μΔa y b) Introduce the adjustment coefficient k t ①a max =|k t a ynmax +α0| ②a min =|k t a ynmax -α0| Where a yn a is the lateral acceleration when the vehicle performs active steering control. y0 The initial lateral acceleration is Δa. y a represents the change in lateral acceleration during active steering. ynmax a is the maximum value of the lateral acceleration variation limit. ynmin For the minimum limit of lateral acceleration variation, α max α is the maximum limit of the rear wheel steering angle. min This is the minimum limit of the rear wheel steering angle.

5. A collaborative control system for preventing folding of semi-trailers as described in claim 1, characterized in that... The anti-folding control module calculates the additional yaw moment required by the differential braking control strategy in the anti-folding cooperative execution module by receiving parameter information from the anti-folding prediction module, and calculates the distribution of braking force based on the additional yaw moment. Step 1: Analysis of the additional torque situation is as follows: We will only discuss understeer and oversteer: If the vehicle turns left at this time 1) If understeering occurs, the yaw moment needs to be compensated by moving the vehicle to the left. 2) If oversteering occurs, the yaw moment needs to be compensated to the right of the vehicle; If the vehicle turns right at this time 1) If understeering occurs, the yaw moment needs to be compensated to the right of the vehicle; 2) If oversteering occurs, the yaw moment needs to be compensated by moving the vehicle to the left. Planning for additional yaw moment based on steering characteristics; Step 2: The calculation of braking torque distribution is as follows: 1) Braking torque of the front axle wheels of the tractor: 2) Braking torque of the rear axle wheels of the tractor: 3) Braking torque of trailer axle wheels: Among them, T l1 T is the torque of the left wheel of the front axle of the tractor. l2 d1 is the right wheel torque of the tractor's front axle, d2 is the left wheel angle stability coefficient of the tractor's front axle, l1 is the track width of the tractor's front axle, r1 is the tire radius of the tractor's front axle, and T is the torque of the right wheel of the tractor's front axle. la1 Braking torque of the left wheel of the front axle of the tractor, T la2 Braking torque of the right wheel of the front axle of the tractor, T q1 Torque of the left wheel of the tractor's rear axle, T q2 The torque of the right wheel of the tractor's rear axle, d3 is the stability coefficient of the left wheel angle of the tractor's rear axle, d4 is the stability coefficient of the right wheel angle of the tractor's rear axle, l2 is the track width of the tractor's rear axle, r2 is the tire radius of the tractor's rear axle, and T is the torque of the right wheel of the tractor's rear axle. lb1 Braking torque of the left wheel of the rear axle of the tractor, T lb2 Braking torque of the right wheel of the tractor's rear axle, T g1 Trailer axle left wheel torque, T g2 The right wheel torque of the trailer axle, d5 is the left wheel angle stability coefficient of the trailer axle, d6 is the right wheel angle stability coefficient of the trailer axle, l3 is the track width of the trailer axle, r3 is the tire radius of the trailer axle, T lc1 Trailer axle left wheel braking torque, T lc2 Braking torque of the right wheel of the trailer axle.

6. A cooperative control system for preventing folding of semi-trailers as described in claim 1, characterized in that... The anti-folding collaborative execution module can use the reverse driving torque of the trailer axle to increase the folding angle of the folded semi-trailer. This reverse drive control can be started autonomously under safe working conditions. When 0≤Y0<2, it is determined to be a safe operating condition; If u≤30km / h and 120°≤θ≤150°, the reverse drive torque will pull the semi-trailer to a folding angle greater than 150°, at which point the reverse drive control will automatically shut off.

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