Semitrailer truck train reversing method and device, electronic equipment and storage medium

Abstract

Embodiments of the present disclosure disclose a method and device for reversing a semi-trailer truck train, electronic equipment and a storage medium. The method constructs a cascaded model corresponding to a target truck train and a reversing constraint including an anti-folding constraint, and then determines a final reversing reference trajectory of a tractor of the target truck train according to an initial control sequence of a last trailer, a pose of the last trailer at a first time, initial hinge angles of each vehicle at the first time, the cascaded model and the reversing constraint, so as to track the trajectory and realize reversing control of the target truck train. The method solves the reversing reference trajectory by constructing the anti-folding constraint and the cascaded model to consider the folding phenomenon in the reversing process, actively avoid the folding phenomenon of the semi-trailer truck train in the reversing process, and then avoid the semi-trailer truck train entering an uncontrollable state, thereby improving the rationality of the reversing reference trajectory and ensuring the reversing safety of the semi-trailer truck train.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of automatic driving, and particularly relates to a semi-trailer train reversing method and device, an electronic device and a storage medium. BACKGROUND

[0002] A train of vehicles usually consists of one towing vehicle and one or more towed trailers constrained by a hitch. If a semi-trailer is carried, it is called a semi-trailer train of vehicles, and if a full trailer is carried, it is called a full-trailer train of vehicles. In logistics scenarios such as ports, airports and factory sites, the unmanned closed-loop process of the semi-trailer train of vehicles has been widely applied to help realize automatic cargo transportation in a set area and improve transportation efficiency. Typical tasks include: receiving a dispatch order, automatically hitching a vehicle, running with a hitch, automatically reversing into a warehouse with a hitch, automatically unhitching and automatically returning to a dispatch area.

[0003] Similar to automatic parking technology, reversing into a warehouse with a hitch is a key link in the full-scenario unmanned operation as a terminal scenario of a factory site. Reversing with a hitch means that, in the reversing process, the hitched trailer is caused to travel along a desired trajectory by continuously adjusting the control amount of the towing vehicle.

[0004] However, the trajectory planning for reversing with a hitch in the prior art only discusses a single trailer, cannot realize trajectory planning for reversing with multiple trailers, and in the aspect of reversing trajectory tracking, unstable driving easily occurs, that is, a jack-knife phenomenon occurs. Once this state is entered, no matter how the control amount of the towing vehicle is adjusted (still reversing), the hitch angle between the trailer and the towing vehicle will continue to increase until parking or mechanical jack-knife collision occurs. SUMMARY

[0005] To solve the above technical problems or at least partially solve the above technical problems, the embodiments of the present disclosure provide a semi-trailer train reversing method, device, electronic device and storage medium, which solve the problem that the prior art cannot realize trajectory planning for reversing with multiple trailers, and avoid the jack-knife phenomenon, thereby ensuring the reversing safety of the semi-trailer train of vehicles.

[0006] In a first aspect, the embodiments of the present disclosure provide a semi-trailer train reversing method, which comprises:

[0007] constructing a cascaded model corresponding to a target train of vehicles and reversing constraints, wherein the cascaded model comprises a motion inverse model, a motion positive model, a hitch angle change model and a pose change model, and the reversing constraints comprise anti-jack-knife constraints;

[0008] determine a final reversing reference trajectory of the tractor vehicle in the target vehicle train based on the initial control quantity sequence of the last trailer in the target vehicle train, the pose of the last trailer at the first time, the initial hinge angle of each vehicle in the target vehicle train at the first time, the cascaded model, and the reversing constraint, wherein the final reversing reference trajectory comprises a final control quantity sequence, a final hinge angle sequence, and a final pose sequence;

[0009] track the final reversing reference trajectory of the tractor vehicle to control the target vehicle train to reverse.

[0010] In a second aspect, the embodiments of the present disclosure further provide a semi-trailer vehicle train reversing device, which comprises:

[0011] a construction module configured to construct a cascaded model corresponding to a target vehicle train and a reversing constraint, wherein the cascaded model comprises a motion inverse model, a motion positive model, a hinge angle change model, and a pose change model, and the reversing constraint comprises an anti-folding constraint;

[0012] a determination module configured to determine a final reversing reference trajectory of the tractor vehicle in the target vehicle train based on the initial control quantity sequence of the last trailer in the target vehicle train, the pose of the last trailer at the first time, the initial hinge angle of each vehicle in the target vehicle train at the first time, the cascaded model, and the reversing constraint, wherein the final reversing reference trajectory comprises a final control quantity sequence, a final hinge angle sequence, and a final pose sequence;

[0013] a tracking module configured to track the final reversing reference trajectory of the tractor vehicle to control the target vehicle train to reverse.

[0014] In a third aspect, the embodiments of the present disclosure further provide an electronic device, which comprises one or more processors, a storage device configured to store one or more programs, and when the one or more programs are executed by the one or more processors, the one or more processors implement the semi-trailer vehicle train reversing method as described above.

[0015] In a fourth aspect, the embodiments of the present disclosure further provide a computer readable storage medium having a computer program stored thereon, and the program is executed by a processor to implement the semi-trailer vehicle train reversing method as described above.

[0016] The semi-trailer truck reversing method provided by the embodiments of the present disclosure comprises the following steps: constructing a cascaded model corresponding to a target truck and a reversing constraint comprising a folding prevention constraint; determining a final reversing reference trajectory of a tractor in the target truck according to an initial control quantity sequence of a last trailer in the target truck, a pose of the last trailer at a first time, initial hinge angles of each vehicle in the target truck at the first time, the cascaded model and the reversing constraint; and tracking the trajectory to realize reversing control of the target truck. The method solves the reversing reference trajectory by constructing the folding prevention constraint and the cascaded model to consider the folding phenomenon in the reversing process, actively avoid the folding phenomenon of the semi-trailer truck in the reversing process, and further avoid the semi-trailer truck entering an uncontrollable state, thereby improving the rationality of the reversing reference trajectory and ensuring the reversing safety of the semi-trailer truck. BRIEF DESCRIPTION OF DRAWINGS

[0017] The above and other features, advantages, and aspects of the embodiments of the present disclosure will become more apparent with reference to the following detailed description when taken in conjunction with the accompanying drawings. Throughout the drawings, the same or similar reference numerals refer to the same or similar elements. It is to be understood that the drawings are schematic, and the sizes of the components and elements are not necessarily drawn to scale.

[0018] Figure 1 A flowchart of a semi-trailer truck reversing method in the embodiments of the present disclosure;

[0019] Figure 2 A turning motion schematic diagram of a semi-trailer truck in the embodiments of the present disclosure;

[0020] Figure 3 A turning critical point schematic diagram of a semi-trailer truck motion model in the embodiments of the present disclosure;

[0021] Figure 4 A geometric collision schematic diagram of a semi-trailer truck in the embodiments of the present disclosure;

[0022] Figure 5 A reversing re-planning schematic diagram of a semi-trailer truck in the embodiments of the present disclosure;

[0023] Figure 6 A structure schematic diagram of a semi-trailer truck reversing device in the embodiments of the present disclosure;

[0024] Figure 7 A structure schematic diagram of an electronic device in the embodiments of the present disclosure. DETAILED DESCRIPTION

[0025] Embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although some embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure can be implemented in various forms and should not be construed as being limited to the embodiments set forth herein, but rather, these embodiments are provided so as to more completely and thoroughly understand the present disclosure. It should be understood that the drawings and embodiments of the present disclosure are only for exemplary purposes and are not intended to limit the scope of protection of the present disclosure.

[0026] It should be noted that the concepts of "first", "second", and the like mentioned in the present disclosure are only used to distinguish different devices, modules or units, and are not intended to limit the order or interdependence of the functions performed by these devices, modules or units.

[0027] The names of the messages or information exchanged between the plurality of devices in the embodiments of the present disclosure are only for illustrative purposes, and are not intended to limit the scope of the messages or information.

[0028] Before the method provided by the embodiments of the present disclosure is described in detail, the technical problems solved by the method are exemplarily described.

[0029] Patent 1 (CN111071338A, a semi-trailer train folding angle prediction method and storage medium) discloses a semi-trailer train straight stable reversing articulation angle determination method. According to the division of the stable domain and the feasible domain of the articulation angle, a driving prompt can be given. In this scheme, it is mainly aimed at straight stable reversing, and the feasible domain and stable domain of the semi-trailer train reversing articulation angle of a single trailer are given.

[0030] Patent 2 (CN113696970A, semi-trailer train, reversing control method, device, equipment and medium) discloses a semi-trailer train, reversing control method, device, equipment and medium, mainly involving a feasible reversing control method for a single semi-trailer train.

[0031] In patent 1, the patent only discusses single trailer reversing and only provides warning information to the driving system based on this constraint, which cannot solve the complete unmanned reversing process problem. In patent 2, the reversing control method disclosed is suitable for routes with smooth trajectories and small fluctuations. In the trajectory generation part, the folding constraint during reversing is not considered, and in the reversing trajectory tracking aspect, the folding phenomenon that is more likely to occur is also not considered, and the entering of the uncontrollable state during reversing cannot be actively avoided.

[0032] Therefore, the aforementioned patents do not consider the folding phenomenon during reversing. To solve this problem, this disclosure provides a method for reversing a semi-trailer truck train. By introducing folding constraints and cascaded models, the folding phenomenon during reversing can be considered, thus avoiding the occurrence of folding and actively preventing the vehicle from entering an uncontrollable state during reversing, thereby improving the rationality of the reference trajectory.

[0033] Figure 1 This is a flowchart illustrating a method for reversing a semi-trailer truck train according to an embodiment of this disclosure. The method provided in this embodiment is applicable to situations where a semi-trailer truck train is reversing with a trailer. This method can be executed by a semi-trailer truck train reversing device, which can be implemented in software and / or hardware and can be configured in an electronic device. For example... Figure 1 As shown, the method may specifically include the following steps:

[0034] S110. Construct a cascaded model corresponding to the target vehicle train and reversing constraints. The cascaded model includes an inverse motion model, a forward motion model, an articulation angle change model, and a pose change model. The reversing constraints include anti-folding constraints.

[0035] The target vehicle train may include a tractor unit and one or more semi-trailers bound by a towing pin. Specifically, the articulation point between the tractor unit and the trailer, or between trailers, may be located slightly rearward from the center of the rear axle of the tractor unit or the trailer.

[0036] For example, Figure 2 This is a schematic diagram of the turning motion of a semi-trailer truck train according to an embodiment of this disclosure, such as... Figure 2 As shown, the target vehicle train can consist of a tractor and at least one trailer (i.e., a trailer). The target vehicle train moves in a horizontal plane. The geodetic coordinate system is OXY, where the X-axis points due east and the Y-axis points due north. To simplify the motion analysis, a single-axis bicycle model is used here. (x0, y0) are the coordinates of the rear axle center of the tractor, θ0 is the heading angle of the tractor in the geodetic coordinate system, and β0 is the deflection angle of the front wheels of the vehicle.

[0037] Considering that the tractor unit carries N (N≥1) trailers, with the tractor unit's attachment point being H0, located directly behind the center of the tractor unit's rear axle, and the distance between H0 and the center of the tractor unit's rear axle is L. h0 For the i-th trailer, 1≤i≤N, its heading angle is denoted as θ. i (x1, y1) represents the absolute position coordinates of the rear axle center of the first trailer in the geodetic coordinate system, and the distance between the attachment point of the i-th trailer and the rear axle center of that trailer is L. hi The wheelbase is denoted as L. i And define its hinge angle as β.i = θ i-1 - θ i In addition, the tractor and the trailer only make two-dimensional plane motion, and the vertical movement is not considered. The control quantity of each vehicle (tractor or trailer) in the target vehicle train can be denoted as [ω i , v i ], ω i is the yaw rate of the ith vehicle, and v i is the speed of the ith vehicle.

[0038] In the embodiment of the present disclosure, the cascade model can be composed of a motion inverse model, a motion positive model, a hinged angle change model, and a pose change model. The motion inverse model can determine the control quantity of the former vehicle according to the control quantity of the latter vehicle of the two adjacent vehicles, for example, can be used to derive the control quantity of the tractor according to the control quantity of the last trailer; the motion positive model can determine the control quantity of the latter vehicle according to the control quantity of the former vehicle of the two adjacent vehicles, for example, can be used to derive the control quantity of the last trailer according to the control quantity of the tractor; the hinged angle change model can determine the hinged angle of the vehicle at the next moment according to the hinged angle of the vehicle at the previous moment; and the pose change model can determine the pose of the vehicle at the next moment according to the pose of the vehicle at the previous moment.

[0039] Specifically, for the trailer, [ω i , v i ] can be used as an intermediate variable to establish a cascade relationship, and the control quantity of the entire target vehicle train is provided by the tractor, that is, the control input of the tracking system of the target vehicle train is the control quantity [ω0, v0] of the tractor. Generally, it can be assumed that the tractor reverses at a constant speed, that is: v0(t) > 0, the steering input of the tractor can be calculated by the Ackerman steering model:

[0040]

[0041] In the embodiment of the present disclosure, [ω0, v0] can be directly used as the control input of the tracking system, which is derived through the cascade model, and the semi-trailer vehicle train of the differential steering system can also be compatible.

[0042] In the embodiment of the present disclosure, according to the single-track kinematic model of the vehicle and the connection relationship of the tractor and the trailer, the motion model of the ith vehicle can be obtained as follows:

[0043]

[0044] v i = L hi-1 sin β i ω i-1+cosβ i v i-1 (3);

[0045] In the formula, L hi-1 L represents the distance between the (i-1)th vehicle's engagement point and its rear axle center. i Let β be the wheelbase of the i-th vehicle. i Let be the hinge angle of the i-th vehicle.

[0046] Specifically, for the first trailer, its motion model is as follows:

[0047]

[0048]

[0049] Furthermore, the above formula can be expressed in the following form, that is, the positive motion model can be:

[0050] u i =J(β) i )u i-1 (6);

[0051] Among them, u i =[ω i v i ], i = 1, 2, ..., N, representing the i-th trailer,

[0052] In this embodiment of the disclosure, the change in the articulation angle between the trailer and the tractor, or the change in the articulation angle between the trailers, can be expressed by the following formula:

[0053]

[0054] Specifically, for the first trailer, the change in its articulation angle is as follows:

[0055]

[0056] Furthermore, formula (7) can be rearranged to obtain the hinge angle variation model:

[0057]

[0058] in, Let c be the change in the articulation angle of the i-th vehicle. T =[1,0],Γ i (β i ) = I 2×2 -J(β i ); through the By integration, the articulated angle of the i-th vehicle at the next time can be obtained.

[0059] In the embodiments of the present disclosure, it is assumed that and J(β i ) is reversible, then the motion inverse model can be obtained:

[0060] u i-1 =J -1 (β i )u i (10);

[0061] wherein u i-1 is the control quantity of the i-1-th vehicle, u i is the control quantity of the i-th vehicle,

[0062]

[0063] In the embodiments of the present disclosure, considering that the tractor and the trailer are both two-dimensional planar motion, the pose change model can be:

[0064]

[0065] In the formula, is the pose change quantity of the i-th vehicle, and the pose q i of the i-th vehicle can be expressed as [θ i x i y i ]; by integration on , the pose of the i-th vehicle at the next time can be obtained.

[0066] By constructing the cascade model, the transmission relationship from the control input of the tracking system to the poses of each trailer and tractor, and the cascade control quantity transmission relationship between each vehicle can be established. Based on the cascade model, it can be known that the control quantity of other vehicles can be derived through the control quantity and the articulated angle of the adjacent vehicle, that is, the control quantity of other i-1-th vehicles can be uniquely derived from the control quantity and the articulated angle of the i-th vehicle; and the change rate of the articulated angle of the current vehicle can be derived through the control quantity of the previous vehicle and the articulated angle of the current vehicle, and then integration can obtain the articulated angle at the future time.

[0067] In the embodiments of the present disclosure, the reversing constraint can be composed of the anti-folding constraint, wherein the anti-folding constraint is used to limit the articulated angle of each vehicle in the target automobile train, so as to avoid the folding phenomenon of the vehicle.

[0068] In a specific embodiment, the reverse constraint corresponding to the target automobile train is constructed, including: for each trailer in the target automobile train, determining a first critical articulation angle of the trailer based on the wheelbase of the trailer, and the hitch point distance and the maximum turning radius of the previous vehicle of the trailer, and constructing an anti-fold constraint of the trailer according to the first critical articulation angle of the trailer; constructing an anti-fold constraint of the target automobile train based on the anti-fold constraints of all trailers in the target automobile train; wherein the hitch point distance is the distance from the corresponding hitch point to the center of the rear axle.

[0069] Exemplary, Figure 3 is a schematic diagram of a turning critical point of a semi-trailer automobile train motion model in an embodiment of the present disclosure, from Figure 3 It can be seen that when the turning radius of the trailer itself is less than the maximum turning radius of the semi-trailer automobile train, the folding (jack-knife) phenomenon will occur in the tracking system. Therefore, when the turning center of the trailer coincides with the maximum turning center of the previous vehicle, the articulation angle between them can be used as a critical value to construct a boundary range, and then the anti-folding constraint of the articulation angle can be obtained.

[0070] Specifically, for each trailer, the wheelbase of the trailer, the hitch point distance and the maximum turning radius of the previous vehicle of the trailer can be used to calculate the corresponding first critical articulation angle; as shown in the following formula:

[0071]

[0072] wherein, Φ mi is the first critical articulation angle of the i-th vehicle, L i is the wheelbase of the i-th trailer, is the hitch point distance of the i-1-th vehicle (trailer / tractor), is the maximum turning radius of the previous vehicle, which can be calculated based on the kinematic model, such as, or can be calibrated by the actual turning condition.

[0073] After calculating the first critical articulation angle of each trailer, further, the anti-folding constraint of the articulation angle corresponding to each trailer can be constructed according to the first critical articulation angle of each trailer, such as:

[0074] [Φ mimin , Φ mimax ] = [-Φ mi , Φ mi ] (13) ;

[0075] Furthermore, based on the anti-folding constraints of all trailers, anti-folding constraints for the entire target truck train can be constructed. Through the above implementation method, the construction of anti-folding constraints is achieved. By limiting the articulation angle, vehicle folding can be prevented, thereby avoiding stopping or mechanical collisions of the semi-trailer truck train during reversing.

[0076] Optionally, the reversing constraints also include geometric collision constraints. Constructing reversing constraints corresponding to the target vehicle train further includes: for each trailer in the target vehicle train, determining the second critical articulation angle of the trailer based on the trailer's engagement front distance, and the engagement point distance and width of the trailer's preceding vehicle; for each trailer in the target vehicle train, determining the third critical articulation angle of the trailer based on the engagement point distance of the trailer's preceding vehicle, and the trailer's width and engagement front distance, and constructing geometric collision constraints for the trailer based on the second and third critical articulation angles; constructing geometric collision constraints for the target vehicle train based on the geometric collision constraints of all trailers in the target vehicle train; wherein, the engagement front distance is the distance from the corresponding traction point to the vehicle's front edge.

[0077] Considering the possibility of geometric collisions between adjacent vehicles in a semi-trailer truck train, such as Figure 4 As shown, Figure 4 This is a geometric collision diagram of a semi-trailer truck train according to an embodiment of this disclosure. Figure 4 Two collision scenarios are illustrated. Specifically, for the first collision scenario, the corresponding second critical articulation angle can be calculated using the distance from the trailer's towing point, the distance from the towing point of the preceding vehicle, and the width, as shown in the following formula:

[0078]

[0079] Where, β il Let be the second critical hinge angle of the i-th vehicle. The distance to the leading edge of the i-th vehicle is the distance from the towing point (which can be understood as the towing point of the previous vehicle) to the leading edge of the vehicle body. w is the distance to the attachment point of the (i-1)th vehicle; i-1 Let be the width of the (i-1)th vehicle.

[0080] For the second type of collision, the corresponding third critical articulation angle can be calculated using the distance between the attachment point of the preceding vehicle and the width and attachment point distance of the trailer, as shown in the following formula:

[0081]

[0082] Where, β′ il Let w be the third critical articulation angle of the i-th vehicle.i Let be the width of the i-th vehicle. Furthermore, for each trailer, geometric collision constraints can be constructed based on the second and third critical hinge angles, as follows:

[0083] [Φ limin Φ limax ] = [-min(β il ,β′ il ), min(β) il ,β′ il (16)

[0084] Furthermore, the geometric collision constraints of the entire target vehicle train can be constructed based on the geometric collision constraints of all trailers. It should be noted that the geometric collision constraints can be determined by the geometry of two adjacent vehicles and do not require real-time calculation. Through the above implementation method, the geometric collision constraints are constructed, and by limiting the articulation angle, geometric collisions between vehicles can be avoided.

[0085] Optionally, the reversing constraint also includes a stability region constraint. Constructing the reversing constraint corresponding to the target vehicle train also includes: for each trailer in the target vehicle train, determining the fourth critical articulation angle of the trailer based on the trailer's wheelbase, as well as the sampled travel distance, maximum articulation angle, and wheelbase of the trailer's predecessor vehicle, and constructing the trailer's stability region constraint based on the trailer's fourth critical articulation angle; constructing the target vehicle train's stability region constraint based on the stability region constraints of all trailers in the target vehicle train; wherein, the sampled travel distance is the distance traveled by the predecessor vehicle within the sampling step.

[0086] Specifically, the calculation process for anti-folding constraints and geometric collision constraints reveals that when the relative dimensions between trailers meet certain conditions, the desired upper and lower boundaries cannot be determined. In this case, the anti-folding constraints and geometric collision constraints can be automatically reduced to...

[0087] Furthermore, by combining the motion relationship between the tractor / previous trailer and the following trailer, the change in the articulation angle Δβ can be obtained. i Relationship with hinge angle:

[0088]

[0089] Where, Δx i-1 Let β be the sampled travel distance of the (i-1)th vehicle (i.e., the distance traveled within the sampling step). i Let L be the articulation angle of the i-th vehicle. i-1is the wheel base of the i-1th vehicle. For the change of the hitch angle of the trailer, in the case of no physical limit, only when the front wheel deflection angle of the tractor (which can be considered as the hitch angle of the former trailer for the former trailer) reaches the maximum value, the change of the hitch angle of the current trailer is the largest. When the front wheel deflection angle of the tractor reaches the maximum value, the following relationship can be established according to the stable state at this time:

[0090]

[0091] wherein, is the fourth critical hitch angle of the i-th vehicle. Further, the stability domain constraint can be constructed as follows:

[0092]

[0093] Further, the stability domain constraint of the entire target motor train can be constructed according to the stability domain constraints of all trailers. Through the above implementation, the construction of the stability domain constraint is realized, and by limiting the hitch angle, the hitch angle of the vehicle can be ensured to be stable within a certain range.

[0094] Alternatively, the reversing constraint also includes the feasible domain constraint, and the reversing constraint corresponding to the target motor train is constructed, and further includes: for each trailer in the target motor train, the hitch angle at which the lateral velocity of the trailer is equal to the longitudinal velocity in the process of reversing the former vehicle of the trailer at the critical steering angle is determined as the fifth critical hitch angle, and the feasible domain constraint of the trailer is constructed according to the fifth critical hitch angle of the trailer; the feasible domain constraint of the target motor train is constructed based on the feasible domain constraints of all trailers in the target motor train.

[0095] Specifically, for each trailer, in the case of straight-line reversing, the hitch angle at which the lateral velocity of the trailer is equal to the longitudinal velocity in the process of reversing while keeping the steering angle of the former trailer at the critical value can be considered as is the feasible domain boundary of the trailer, which can be determined by the calibration process before the trailer reverses. That is, the hitch angle at which the lateral velocity of the trailer is equal to the longitudinal velocity in the process of reversing the former vehicle or the tractor at the critical steering angle can be determined as the fifth critical hitch angle of the trailer. For example:

[0096]

[0097] Further, the feasible domain constraint of the entire target motor train can be constructed according to the feasible domain constraints of all trailers. Through the above implementation, the construction of the feasible domain constraint is realized, and by limiting the hitch angle, the feasibility of the hitch angle of the vehicle can be ensured.

[0098] It should be noted that if the reversing constraint is composed of at least one constraint, for example, at least two of the anti-folding constraint, the geometric collision constraint, the stability domain constraint and the feasible domain constraint, the lower limit of the boundary range of the reversing constraint can take the maximum value of the lower limit of all constraints, and the upper limit of the boundary range can take the minimum value of the upper limit of all constraints. For example, the lower limit of the boundary range of the reversing constraint can take the maximum value of the lower limit of all constraints, and the upper limit of the boundary range can take the minimum value of the upper limit of all constraints. The upper limit of the boundary range can take: The boundary range of the reversing constraint is: [Φ imin ,Φ imax ], and the reversing constraint is used to limit the articulation angle β i ∈[Φ imin ,Φ imax ] of the trailer.

[0099] In the embodiments of the present disclosure, the geometric collision constraint, the anti-folding constraint, the stability domain constraint and the feasible domain constraint of the semi-trailer train reversing are considered, and the constructed constraint is used in the reversing reference trajectory planning to improve the rationality of the reversing reference trajectory.

[0100] In S120, the final reversing reference trajectory of the tractor of the target vehicle train is determined based on the initial control quantity sequence of the last trailer in the target vehicle train, the pose of the last trailer at the first time, the initial articulation angle of each vehicle in the target vehicle train at the first time, the cascaded model and the reversing constraint.

[0101] The final reversing reference trajectory includes a final control quantity sequence, a final articulation angle sequence and a final pose sequence. The final control quantity sequence can be composed of final control quantities at each time, the final articulation angle sequence can be composed of final articulation angles at each time, and the final pose sequence can be composed of final poses at each time.

[0102] In the embodiments of the present disclosure, the expected driving route of the last trailer in the target vehicle train can be determined first, which is used as a basic reference path. Further, based on the basic reference path, the initial reversing reference trajectory of the last trailer can be obtained by using a waypoint-oriented tracking algorithm, such as a pure tracking algorithm, i.e., the initial reference path is discretized by time. Based on the initial reversing reference trajectory of the last trailer, the initial control quantity sequence of the last trailer and the pose of the last trailer at the first time

[0103] In addition, considering that there are multiple trailers in the target vehicle train, it can be assumed that the articulation angle of each vehicle at the first time in the initial reversing reference trajectory is equal to the articulation angle of each vehicle in the target vehicle train at the current time, and the initial articulation angle of each vehicle at the first time is obtained, i.e.,

[0104]

[0105] Further, based on the initial control variable sequence of the last trailer in the target motor train, the initial pose of the last trailer at the first time, the initial articulation angle of each vehicle in the target motor train at the first time, the cascading model and the reversing constraint, the final reversing reference trajectory of the tractor in the target motor train is determined, including the following steps: q rN (0), the final control variable sequence of the tractor, the final articulation angle sequence of the tractor and the final pose sequence of the tractor are obtained, which are further taken as the final reversing reference trajectory of the tractor. r (0), the final control variable sequence of the tractor, the final articulation angle sequence of the tractor and the final pose sequence of the tractor are obtained, which are further taken as the final reversing reference trajectory of the tractor.

[0106] In a specific embodiment, based on the initial control variable sequence of the last trailer in the target motor train, the initial pose of the last trailer at the first time, the initial articulation angle of each vehicle in the target motor train at the first time, the cascading model and the reversing constraint, the final reversing reference trajectory of the tractor in the target motor train is determined, including the following steps:

[0107] Step 11, in the case that the target motor train includes a tractor and a single trailer, taking the first time as the current time, determining the initial control variable of the tractor at the current time according to the inverse kinematics model, the initial control variable of the trailer at the current time in the initial control variable sequence of the trailer and the initial articulation angle of the trailer at the current time;

[0108] Step 12, determining the initial articulation angle of the trailer at the next time according to the articulation angle change model, the initial articulation angle of the trailer at the current time and the initial control variable of the tractor at the current time;

[0109] Step 13, taking the next time as a new current time, returning to execute the step of determining the initial control variable of the tractor at the current time according to the inverse kinematics model, the initial control variable of the trailer at the current time in the initial control variable sequence of the trailer and the initial articulation angle of the trailer at the current time, until the current time is the last time, obtaining the initial control variable sequence of the tractor and the initial articulation angle sequence of the trailer;

[0110] Step 14, updating the initial articulation angle sequence of the trailer based on the reversing constraint, and determining the final control variable sequence of the trailer according to the updated initial articulation angle sequence of the trailer;

[0111] Step 15, determining the final control variable sequence of the tractor based on the final control variable sequence of the trailer and the forward kinematics model, and determining the final articulation angle sequence of the tractor according to the initial articulation angle of the tractor at the first time, the final control variable sequence of the tractor and the articulation angle change model;

[0112] Step 16, determining the final pose sequence of the tractor according to the initial pose of the tractor at the first time, the final control variable sequence of the tractor and the pose change model.

[0113] In the embodiments of the present disclosure, when the number of trailers in the target automobile train is 1, the final reversing reference trajectory of the towing vehicle can be derived through the motion inverse model, the articulated angle change model and the pose change model in the cascade model.

[0114] Specifically, the first time can be taken as the current time, and the initial control quantity of the trailer at the current time in the initial control quantity sequence of the trailer and the initial articulated angle of the trailer at the current time can be substituted into the motion inverse model to obtain the initial control quantity of the towing vehicle at the current time. For example, the initial control quantity of the towing vehicle at the current time can be calculated through the formula:

[0115]

[0116] wherein u r is the initial control quantity of each vehicle at the first time, is the initial control quantity of the 0th vehicle (i.e. the towing vehicle) at the first time, is the initial control quantity of the Nth vehicle at the first time, is the initial articulated angle of the jth vehicle at the first time.

[0117] Further, the initial control quantity of the towing vehicle at the current time and the initial articulated angle of the trailer at the current time can be substituted into the articulated angle change model to obtain the initial articulated angle of the trailer at the next time. For example, the articulated angle change model can be discretized by combining the Euler method to obtain:

[0118]

[0119] wherein Δt is the discrete step, i.e. the time difference between two adjacent times, and further, the initial articulated angle of the trailer at the next time can be obtained through the discretized articulated angle change model:

[0120]

[0121] Further, the next time can be taken as a new current time, and steps 11-12 can be returned to obtain the initial control quantity of the towing vehicle at the new current time, and so on, until the initial control quantity of the towing vehicle at all times, i.e. the initial control quantity sequence of the towing vehicle, and the initial articulated angle of the trailer at all times, i.e. the initial articulated angle sequence of the trailer, are obtained.

[0122] Further, the initial articulated angle sequence of the trailer can be updated through the reversing constraint so that each initial articulated angle in the initial articulated angle sequence of the trailer satisfies the reversing constraint, i.e. is within the boundary range of the reversing constraint.

[0123] For the above step 14, optionally, the initial articulation angle sequence of the trailer is updated based on the reverse constraint, and the final control quantity sequence of the trailer is determined according to the updated initial articulation angle sequence of the trailer, including the following steps:

[0124] Step 21, judge whether there is a time corresponding to the initial articulation angle of the trailer in the initial articulation angle sequence of the trailer that violates the reverse constraint;

[0125] Step 22, for the time that violates the reverse constraint, update the initial articulation angle at the time based on the critical articulation angle in the reverse constraint, and determine the articulation angle change value at the time based on the updated initial articulation angle and the articulation angle change model, and determine the yaw rate of the tractor at the previous time of the time based on the articulation angle change value at the time;

[0126] Step 23, determine the final control quantity of the tractor at the previous time based on the yaw rate of the tractor at the previous time, and determine the final control quantity of the trailer at the previous time based on the final control quantity of the tractor at the previous time;

[0127] Step 24, update the initial control quantity sequence of the trailer based on the final control quantity of the trailer at the previous time, and obtain the final control quantity sequence of the trailer.

[0128] Specifically, it can be judged whether each initial articulation angle of the trailer violates the reverse constraint, and if there is an initial articulation angle that violates the reverse constraint, it is updated based on the critical articulation angle in the reverse constraint, such as using the critical articulation angle closest to the initial articulation angle in the boundary range of the reverse constraint to update the initial articulation angle.

[0129] Further, according to the updated initial articulation angle and the articulation angle change model, the articulation angle change value at the time can be calculated:

[0130]

[0131] Where, assuming that the speed of the tractor is low and fluctuates little during the reversing process, then v0(k)≈v0(k-1)≈v0(0). Further, according to the articulation angle change value at the time, the yaw rate of the tractor at the previous time of the time can be determined:

[0132]

[0133] Further, according to the yaw rate of the tractor at the previous time of the time, the final control quantity of the tractor at the previous time is calculated:

[0134]

[0135] Further, based on the final control quantity of the towing vehicle at the previous time, the final control quantity of the trailer at the previous time is calculated:

[0136]

[0137] Further, according to the final control quantity of the trailer at the previous time, the initial control quantity sequence of the trailer can be updated to obtain the final control quantity sequence of the trailer. For example, the final control quantity sequence of the trailer is Through the implementation, the control quantity of the trailer is corrected according to the reversing constraint, and the safety of the finally planned trajectory is ensured.

[0138] For the above step 24, in an example, the initial control quantity sequence of the trailer is updated based on the final control quantity of the trailer at the previous time to obtain the final control quantity sequence of the trailer, including: using the final control quantity of the trailer at the previous time to replace the initial control quantity at the previous time in the initial control quantity sequence of the trailer; for each time after the previous time, based on the final control quantity of the trailer at the previous time, the motion positive model, and the hinge angle change model, the final control quantity of the trailer at each time is determined to obtain the final control quantity sequence of the trailer.

[0139] Specifically, the final control quantity sequence of the trailer can be obtained by using the final control quantity of the trailer at the previous time to replace the initial control quantity at the previous time in the initial control quantity sequence of the trailer.

[0140] Alternatively, the final control quantity at each time after the previous time can also be solved based on the motion positive model and the hinge angle change model, and then the final control quantity sequence of the trailer can be constructed by combining the initial control quantity at each time before the previous time, the final control quantity at the previous time, and the final control quantity at each time after the previous time. Through this way, the corrected trajectory can be closer to the original target location, and the reliability of the trajectory is ensured.

[0141] After obtaining the final control quantity sequence of the trailer based on the reversing constraint, further, the final control quantity sequence of the trailer and the updated initial hinge angle sequence of the trailer can be substituted into the motion positive model to derive the final control quantity of the towing vehicle at each time to obtain the final control quantity sequence. Further, according to the initial hinge angle of the towing vehicle at the first time, the final control quantity sequence of the towing vehicle, and the hinge angle change model, the final hinge angle sequence of the towing vehicle can be derived. And according to the initial pose of the towing vehicle at the first time and the final control quantity sequence of the towing vehicle, it is substituted into the pose change model, the final pose of the towing vehicle at each time can be derived to obtain the final pose sequence of the towing vehicle.

[0142] By the above embodiment, the solution of the final reversing reference trajectory of the towing vehicle under the single trailer is realized, and a final reversing reference trajectory of the trailer which does not violate the reversing constraint is obtained The final reversing reference trajectory of the towing vehicle

[0143] In the embodiments of the present disclosure, in addition to the above-mentioned embodiments, the final reversing reference trajectory can also be solved based on an optimization problem for multiple trailers or a single trailer.

[0144] In another specific embodiment, based on the initial control quantity sequence of the last trailer in the target vehicle train, the pose of the last trailer at the first time, the initial hinge angle of each vehicle in the target vehicle train at the first time, the cascaded model and the reversing constraint, the final reversing reference trajectory of the towing vehicle in the target vehicle train is determined, including the following steps:

[0145] Step 31, taking the minimum of the control quantity deviation of the last trailer at each time and the hinge angle deviation of each vehicle as the target, and taking the reversing constraint, the motion positive model and the hinge angle change model as the constraint conditions, a target optimization problem is constructed;

[0146] Step 32, based on the initial control quantity sequence of the last trailer in the target vehicle train, the pose of the last trailer at the first time, and the initial hinge angle of each vehicle at the first time, the target optimization problem is solved to obtain the final reversing reference trajectory of the last trailer;

[0147] Step 33, based on the final reversing reference trajectory of the last trailer, the hinge angle change model and the motion inverse model, the final reversing reference trajectory of the towing vehicle is determined.

[0148] Wherein, the control quantity deviation can be the difference between the initial control quantity and the final control quantity, and the hinge angle deviation can be the difference between the initial hinge angle and the final hinge angle. For example, the target optimization problem can be:

[0149]

[0150]

[0151]

[0152]

[0153] Wherein, Q s and Q u are the weight coefficients of the hinge angle deviation and the control quantity deviation, respectively. is the final control quantity of the last trailer at the k time, βk-1is the initial control amount of the last trailer at the kth time point, r (k) is the initial articulation angle of each vehicle at the kth time point, is the final articulation angle of each vehicle at the kth time point.

[0154] Specifically, the initial control amount sequence of the last trailer, the pose of the last trailer at the first time point, and the initial articulation angle of each vehicle at the first time point can be taken as known quantities, and the target optimization problem is solved to obtain the final control amount sequence of the last trailer and the final articulation angle sequence. In combination with the pose change model, the final pose sequence of the last trailer can be further obtained to generate the final reversing reference trajectory of the last trailer. Further, the final reversing reference trajectory of the towing vehicle can be derived.

[0155] By taking the minimum of the control amount deviation of the last trailer at each time point and the articulation angle deviation of each vehicle as the target, and combining the reversing constraint, the motion positive model and the articulation angle change model to construct the target optimization problem, the trajectory obtained by solving can not violate the anti-folding constraint, ensuring the rationality and safety of the trajectory and preventing folding phenomenon in the actual driving process.

[0156] S130, tracking the final reversing reference trajectory of the towing vehicle to control the reversing of the target automobile train.

[0157] Specifically, after obtaining the final reversing reference trajectory of the towing vehicle, it can be taken as the input of the tracking system of the target automobile train to track the final reversing reference trajectory and realize the reversing control of the target automobile train.

[0158] Considering that the folding constraint must also be ensured during reversing in the process of tracking the final reversing reference trajectory of the towing vehicle, the final reversing reference trajectory can also be optimized and solved during the reversing tracking process.

[0159] Optionally, tracking the final reversing reference trajectory of the towing vehicle to control the reversing of the target automobile train includes: taking the final control amount sequence of the towing vehicle as the input of the tracking system of the target automobile train to track the final reversing reference trajectory of the towing vehicle through the tracking system; in the process of tracking the final reversing reference trajectory of the towing vehicle through the tracking system, taking the minimization of the calculation result of the pre-constructed cost function as the target and taking the reversing constraint as the constraint condition to update the final reversing reference trajectory of the towing vehicle; wherein the cost function is used to calculate the cost according to the control amount deviation and the pose deviation.

[0160] Wherein, the pose deviation can include lateral displacement deviation, longitudinal displacement deviation and heading angle deviation. For example, the cost function can be:

[0161]

[0162] wherein, represents the final pose of the tractor at the kth moment, x0(k), y0(k), θ0(k), u0(k) represent the pose of the tractor at the kth moment solved by the cost function, Q x , Q y , Q θ , Q u are the weights corresponding to the lateral displacement deviation, the longitudinal displacement deviation, the heading angle deviation and the control amount deviation, respectively.

[0163] Specifically, the calculation result of the cost function can be taken as the target to be minimized, and the solution is solved under the constraint condition of the reversing constraint, and the final reversing reference trajectory of the tractor is updated according to the solution result. Through this way, it can further ensure that the folding phenomenon will not appear in the process of trajectory tracking, and further improve the reversing safety of the semi-trailer train.

[0164] In actual application process, the actual reversing pose of the trailer at the initial moment may be affected by artificial influence or external factors, and the trailer may be in an unstable state or a critical stable state during reversing, that is, At this time, due to the limitation of road boundary or surrounding environment, it is not possible to directly start the stable reversing action with the trailer. Therefore, in the embodiment of the present disclosure, the starting point can also be selected to plan the reversing reference trajectory.

[0165] Optionally, before determining the final reversing reference trajectory of the tractor in the target train based on the initial control amount sequence of the last trailer in the target train, the pose of the last trailer at the first moment, the initial articulation angle of each vehicle in the target train at the first moment, the cascaded model and the reversing constraint, the method further comprises:

[0166] determining whether there is a vehicle in the target train that violates the reversing constraint at the first moment, if so, switching the target train to forward mode driving until a preset stop driving condition is met, to update the pose of the last trailer at the first moment, the initial articulation angle of each vehicle at the first moment and the initial control amount sequence of the last trailer.

[0167] wherein, the first moment can be the current moment, that is, before trajectory planning, it can be determined whether there is a vehicle in the target train that violates the reversing constraint. If so, the target train is switched to forward mode driving until a preset stop driving condition is met, to update the pose of the last trailer at the first moment, the initial articulation angle of each vehicle at the first moment and the initial control amount sequence of the last trailer.

[0168] Specifically, the preset stop driving condition can be driving to a preset distance, or the preset stop driving condition can be driving to a vehicle in the target vehicle train that does not violate the reversing constraint, etc. Through the above embodiments, the feasibility of practical application and the integrity of unmanned operation can be improved.

[0169] Exemplary, Figure 5 is a schematic diagram of the reversing re-planning of a semi-trailer vehicle train in an embodiment of the present disclosure. As shown in Figure 5 , the target vehicle train is in an unstable state of reversing at position B. At this time, the re-planning function can be triggered, and the target vehicle train will switch to forward mode and drive for a certain distance, and select a new position point, such as Figure 5 A point in the figure, adjust the pose after driving to the A point, and then take the A point as the starting point to plan the reversing reference trajectory to the target point C.

[0170] The semi-trailer vehicle train reversing method provided in this embodiment determines the final reversing reference trajectory of the tractor in the target vehicle train according to the initial control quantity sequence of the last trailer in the target vehicle train, the pose of the last trailer at the first time, the initial hinging angle of each vehicle in the target vehicle train at the first time, the cascaded model, and the reversing constraint, so as to track the trajectory and realize the reversing control of the target vehicle train. The method solves the reversing reference trajectory by constructing the anti-folding constraint and the cascaded model to consider the folding phenomenon in the reversing process, actively avoid the folding phenomenon of the semi-trailer vehicle train in the reversing process, and further avoid the semi-trailer vehicle train entering an uncontrollable state, thereby improving the rationality of the reversing reference trajectory and ensuring the reversing safety of the semi-trailer vehicle train.

[0171] Figure 6 is a structural schematic diagram of a semi-trailer vehicle train reversing device in an embodiment of the present disclosure. As shown in Figure 6 , the device includes a construction module 610, a determination module 620, and a tracking module 630.

[0172] The construction module 610 is configured to construct a cascaded model corresponding to a target vehicle train and a reversing constraint. The cascaded model includes a motion inverse model, a motion positive model, a hinging angle change model, and a pose change model. The reversing constraint includes an anti-folding constraint.

[0173] The determining module 620 is used to determine the final reversing reference trajectory of the tractor in the target vehicle train based on the initial control quantity sequence of the last trailer in the target vehicle train, the pose of the last trailer at the first moment, the initial articulation angle of each vehicle in the target vehicle train at the first moment, the cascaded model, and the reversing constraints. The final reversing reference trajectory includes the final control quantity sequence, the final articulation angle sequence, and the final pose sequence.

[0174] The tracking module 630 is used to track the final reversing reference trajectory of the tractor vehicle in order to control the reversing of the target vehicle train.

[0175] The semi-trailer truck reversing device provided in this embodiment can execute the steps in the semi-trailer truck reversing method provided in this embodiment, and has the execution steps and beneficial effects, which will not be repeated here.

[0176] Figure 7 This is a schematic diagram of the structure of an electronic device according to an embodiment of this disclosure. See below for details. Figure 7 It shows a schematic diagram of a structure suitable for implementing the electronic device 500 in the embodiments of this disclosure. Figure 7 The electronic device shown is merely an example and should not be construed as limiting the functionality and scope of the embodiments disclosed herein.

[0177] like Figure 7 As shown, the electronic device 500 may include a processing device (e.g., a central processing unit, a graphics processor, etc.) 501, which can perform various appropriate actions and processes to implement the methods of the embodiments described herein, based on a program stored in a read-only memory (ROM) 502 or a program loaded from a storage device 508 into a random access memory (RAM) 503. The RAM 503 also stores various programs and data required for the operation of the electronic device 500. The processing device 501, ROM 502, and RAM 503 are interconnected via a bus 504. An input / output (I / O) interface 505 is also connected to the bus 504.

[0178] In particular, according to embodiments of the present disclosure, the processes described above with reference to the flowcharts can be implemented as a computer software program. For example, embodiments of the present disclosure include a computer program product comprising a computer program carried on a non-transitory computer-readable medium, the computer program containing program code for executing the methods illustrated by the flowcharts, thereby implementing the method of semi-trailer reversing as described above. In such embodiments, the computer program can be downloaded and installed from a network by the communication device 509, or installed from the storage device 508, or installed from the ROM 502. When the computer program is executed by the processing device 501, the above-mentioned functions defined in the method of embodiments of the present disclosure are executed.

[0179] It should be noted that the computer-readable medium described above in the present disclosure can be a computer-readable signal medium or a computer-readable storage medium or any combination thereof. The computer-readable storage medium, for example, can be, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, device, or apparatus, or any suitable combination thereof. More specific examples of the computer-readable storage medium can include, but are not limited to, an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination thereof. In the present disclosure, the computer-readable storage medium can be any tangible medium that contains or stores a program that can be used by or in connection with an instruction execution system, apparatus, or device. In the present disclosure, the computer-readable signal medium can include a data signal that propagates in a baseband or as part of a carrier wave, carrying computer-readable program code. Such a propagated data signal can take many forms, including but not limited to electro-magnetic, optical, or any suitable combination thereof. The computer-readable signal medium can also be any computer-readable medium that can be used to carry or store program code for use by or in connection with an instruction execution system, apparatus, or device. The program code contained in the computer-readable medium can be transmitted in any suitable form, including but not limited to electrical, optical, RF (radio frequency), or any suitable combination thereof, or any suitable combination thereof.

[0180] The computer-readable medium described above can be included in the electronic device described above; or can exist separately from the electronic device and be not assembled in the electronic device. The computer-readable medium described above carries one or more programs, which, when executed by the electronic device, cause the electronic device to:

[0181] construct a cascaded model corresponding to the target automobile train and a reversing constraint, wherein the cascaded model comprises a motion inverse model, a motion positive model, a hinged angle change model and a pose change model, and the reversing constraint comprises an anti-folding constraint;

[0182] determine a final reversing reference trajectory of the towing vehicle in the target automobile train based on an initial control quantity sequence of a last trailer in the target automobile train, a pose of the last trailer at a first time, initial hinged angles of each vehicle in the target automobile train at the first time, the cascaded model and the reversing constraint, wherein the final reversing reference trajectory comprises a final control quantity sequence, a final hinged angle sequence and a final pose sequence;

[0183] track the final reversing reference trajectory of the towing vehicle to control the target automobile train to reverse.

[0184] Optionally, when the one or more programs are executed by the electronic device, the electronic device can further execute other steps described in the above embodiments.

[0185] In the context of the present disclosure, a machine-readable medium can be a tangible medium that can contain or store a program for use by or in connection with an instruction execution system, apparatus, or device. The machine-readable medium can be a machine-readable signal medium or a machine-readable storage medium. The machine-readable medium can include, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the above. More specific examples of the machine-readable storage medium will include one or more lines of electrical connections, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fibers, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination of the above.

[0186] Scheme 1, a method for reversing a semi-trailer automobile train, the method comprising:

[0187] construct a cascaded model corresponding to the target automobile train and a reversing constraint, wherein the cascaded model comprises a motion inverse model, a motion positive model, a hinged angle change model and a pose change model, and the reversing constraint comprises an anti-folding constraint;

[0188] determine a final reversing reference trajectory of the towing vehicle in the target vehicle train based on the initial control quantity sequence of the last trailer in the target vehicle train, the pose of the last trailer at the first time, the initial hinge angle of each vehicle in the target vehicle train at the first time, the cascade model and the reversing constraint, wherein the final reversing reference trajectory comprises a final control quantity sequence, a final hinge angle sequence and a final pose sequence;

[0189] track the final reversing reference trajectory of the towing vehicle to control the target vehicle train to reverse.

[0190] Scheme 2, the method according to scheme 1, constructing the reversing constraint corresponding to the target vehicle train comprises:

[0191] for each trailer in the target vehicle train, determining a first critical hinge angle of the trailer based on the wheelbase of the trailer, the hitch point distance of the previous vehicle of the trailer and the maximum turning radius, and constructing the anti-folding constraint of the trailer according to the first critical hinge angle of the trailer;

[0192] constructing the anti-folding constraint of the target vehicle train based on the anti-folding constraints of all trailers in the target vehicle train;

[0193] wherein the hitch point distance is the distance from the corresponding hitch point to the center of the rear axle.

[0194] Scheme 3, the method according to scheme 2, the reversing constraint further comprises a geometric collision constraint, and the constructing the reversing constraint corresponding to the target vehicle train further comprises:

[0195] for each trailer in the target vehicle train, determining a second critical hinge angle of the trailer based on the hitch front distance of the trailer, the hitch point distance of the previous vehicle of the trailer and the width;

[0196] for each trailer in the target vehicle train, determining a third critical hinge angle of the trailer based on the hitch point distance of the previous vehicle of the trailer, the width of the trailer and the hitch front distance, and constructing the geometric collision constraint of the trailer according to the second critical hinge angle and the third critical hinge angle of the trailer;

[0197] constructing the geometric collision constraint of the target vehicle train based on the geometric collision constraints of all trailers in the target vehicle train;

[0198] wherein the hitch front distance is the distance from the corresponding hitch point to the front edge of the vehicle body.

[0199] The method according to scheme 2, wherein the reverse constraints further comprise stability region constraints, and the constructing the reverse constraints corresponding to the target vehicle train further comprises:

[0200] For each trailer in the target vehicle train, determining a fourth critical articulation angle of the trailer based on a wheelbase of the trailer, and a sampled travel distance, a maximum articulation angle and a wheelbase of a previous vehicle of the trailer, and constructing a stability region constraint of the trailer according to the fourth critical articulation angle of the trailer;

[0201] Constructing a stability region constraint of the target vehicle train based on the stability region constraints of all trailers in the target vehicle train.

[0202] The sampled travel distance is a distance traveled by the previous vehicle within a sampling step.

[0203] The method according to scheme 2, wherein the reverse constraints further comprise feasible region constraints, and the constructing the reverse constraints corresponding to the target vehicle train further comprises:

[0204] For each trailer in the target vehicle train, determining a fifth critical articulation angle of the trailer, which is an articulation angle that makes a lateral velocity of the trailer equal to a longitudinal velocity during a process of reversing the previous vehicle of the trailer at a critical steering angle, and constructing a feasible region constraint of the trailer according to the fifth critical articulation angle of the trailer;

[0205] Constructing a feasible region constraint of the target vehicle train based on the feasible region constraints of all trailers in the target vehicle train.

[0206] The method according to scheme 1, wherein the determining the final reverse reference trajectory of the tractor in the target vehicle train based on the initial control quantity sequence of the last trailer in the target vehicle train, the initial pose of the last trailer at the first time, the initial articulation angles of all vehicles in the target vehicle train at the first time, the cascaded model and the reverse constraints comprises:

[0207] In a case where the target vehicle train comprises a tractor and a single trailer, taking the first time as a current time, determining an initial control quantity of the tractor at the current time according to the motion inverse model, an initial control quantity of the trailer at the current time in the initial control quantity sequence of the trailer, and an initial articulation angle of the trailer at the current time;

[0208] Determining an initial articulation angle of the trailer at a next time according to the articulation angle change model, the initial articulation angle of the trailer at the current time, and the initial control quantity of the tractor at the current time;

[0209] determining the initial control quantity sequence of the towing vehicle and the initial articulation angle sequence of the trailer based on the initial control quantity sequence of the trailer, the initial articulation angle sequence of the trailer, and the articulation angle change model until the current time is the last time, obtaining the initial control quantity sequence of the towing vehicle and the initial artication angle sequence of the trailer;

[0210] updating the initial articulation angle sequence of the trailer based on the reverse constraint, and determining the final control quantity sequence of the trailer based on the updated initial articulation angle sequence of the trailer;

[0211] determining the final control quantity sequence of the towing vehicle based on the final control quantity sequence of the trailer and the positive motion model, and determining the final articulation angle sequence of the towing vehicle based on the initial articulation angle of the towing vehicle at the first time, the final control quantity sequence of the towing vehicle, and the articulation angle change model;

[0212] determining the final pose sequence of the towing vehicle based on the initial pose of the towing vehicle at the first time, the final control quantity sequence of the towing vehicle, and the pose change model.

[0213] In scheme 7, the updating of the initial articulation angle sequence of the trailer based on the reverse constraint and the determination of the final control quantity sequence of the trailer based on the updated initial articulation angle sequence of the trailer include:

[0214] determining whether there is a time corresponding to the initial articulation angle sequence of the trailer that violates the reverse constraint;

[0215] for the time that violates the reverse constraint, updating the initial articulation angle at the time based on the critical articulation angle in the reverse constraint, and determining the articulation angle change value at the time based on the updated initial articulation angle and the articulation angle change model, and determining the yaw angular velocity of the towing vehicle at the previous time of the time based on the articulation angle change value at the time;

[0216] determining the final control quantity of the towing vehicle at the previous time based on the yaw angular velocity of the towing vehicle at the previous time, and determining the final control quantity of the trailer at the previous time based on the final control quantity of the towing vehicle at the previous time;

[0217] updating the initial control quantity sequence of the trailer based on the final control quantity of the trailer at the previous time, and obtaining the final control quantity sequence of the trailer.

[0218] The method according to the method of scheme 7, the final control quantity sequence of the trailer is updated based on the final control quantity of the trailer at the previous time, and the final control quantity sequence of the trailer is obtained, including:

[0219] The final control quantity of the trailer at the previous time is used to replace the initial control quantity of the trailer at the previous time in the initial control quantity sequence of the trailer;

[0220] For each time after the previous time, the final control quantity of the trailer at each time is determined based on the final control quantity of the trailer at the previous time, the motion positive model, and the hinge angle change model, and the final control quantity sequence of the trailer is obtained.

[0221] The method according to the method of scheme 1, the final reversing reference trajectory of the tractor in the target automobile train is determined based on the initial control quantity sequence of the last trailer in the target automobile train, the pose of the last trailer at the first time, the initial hinge angle of each vehicle in the target automobile train at the first time, the cascade model and the reversing constraint, including:

[0222] An objective optimization problem is constructed with the minimum deviation of the control quantity of the last trailer at each time and the hinge angle deviation of each vehicle as the target, and with the reversing constraint, the motion positive model and the hinge angle change model as the constraint condition;

[0223] The target optimization problem is solved based on the initial control quantity sequence of the last trailer in the target automobile train, the pose of the last trailer at the first time, and the initial hinge angle of each vehicle at the first time, and the final reversing reference trajectory of the last trailer is obtained;

[0224] The final reversing reference trajectory of the tractor is determined based on the final reversing reference trajectory of the last trailer, the hinge angle change model and the motion inverse model.

[0225] The method according to the method of scheme 1, the final reversing reference trajectory of the tractor is tracked to control the reversing of the target automobile train, including:

[0226] The final control quantity sequence of the tractor is used as the input of the tracking system of the target automobile train, so that the final reversing reference trajectory of the tractor is tracked by the tracking system;

[0227] In the process that the tracking system tracks the final reversing reference trajectory of the tractor, the final reversing reference trajectory of the tractor is updated with the minimum calculation result of the pre-constructed cost function as the target and with the reversing constraint as the constraint condition;

[0228] The cost function is used to calculate a cost according to a control quantity deviation and a pose deviation.

[0229] Scheme 11, the method according to scheme 1, before determining the final reversing reference trajectory of the tractor of the target automobile train based on the initial control quantity sequence of the last trailer in the target automobile train, the pose of the last trailer at the first time, the initial hinge angle of each vehicle in the target automobile train at the first time, the cascade model and the reversing constraint, further comprising:

[0230] determining whether there is a vehicle in the target automobile train that violates the reversing constraint at the first time, if so, switching the target automobile train to forward mode driving until a preset stop driving condition is met to update the pose of the last trailer at the first time, the initial hinge angle of each vehicle at the first time and the initial control quantity sequence of the last trailer.

[0231] Scheme 12, a semi-trailer automobile train reversing device, comprising:

[0232] A first determination module is configured to determine at least one pose of the vehicle through at least one positioning method within a set time window when the vehicle is in a driving state, wherein the poses determined through different positioning methods are different.

[0233] A first correction module is configured to perform a first correction on an initial pose obtained through a wheel speed odometer based on a target pose in the at least one pose to obtain a first correction result.

[0234] A second correction module is configured to continue to correct the first correction result based on road information obtained within the set time window to obtain a second correction result, wherein the road information includes road identification, three-dimensional points constituting the road identification and a collection timestamp of the three-dimensional points.

[0235] A second determination module is configured to obtain a final positioning result of the vehicle based on the second correction result.

[0236] Scheme 13, an electronic device, comprising:

[0237] one or more processors;

[0238] a storage device configured to store one or more programs;

[0239] when the one or more programs are executed by the one or more processors, the one or more processors implement the method according to any one of schemes 1-11.

[0240] Scheme 14. A computer readable storage medium having stored thereon a computer program which, when executed by a processor, implements the method of any one of schemes 1-11.

[0241] The above description is merely illustrative of the exemplary embodiments of this disclosure and the principles thereof. It will thus be appreciated that those skilled in the art will be able to devise numerous alternative arrangements based on the principles described herein without departing from the scope of the disclosure as set forth in the appended claims. For example, the features described above and illustrated in the accompanying drawings are meant only to exemplify possible features of the present disclosure. Numerous other features, not described or shown, are contemplated as being within the scope of the present disclosure. For instance, features disclosed in the background section, in the summary of the application, in the abstract, in the claims, in the description of the figures, in the examples, or in the detailed description of the embodiments, are all contemplated as being within the scope of the present disclosure.

Claims

1. A method of reversing a semitrailer truck, characterized by, The method comprises: constructing a cascade model corresponding to a target automobile train and a reversing constraint, wherein the cascade model comprises a motion inverse model, a motion positive model, a hinged angle change model, and a pose change model, the reversing constraint comprises an anti-folding constraint, the motion inverse model determines a control quantity of a front vehicle among two adjacent vehicles according to a control quantity of a rear vehicle, the motion positive model determines a control quantity of a rear vehicle among two adjacent vehicles according to a control quantity of a front vehicle, the hinged angle change model determines a hinged angle of a vehicle at a next time according to a hinged angle of the vehicle at a previous time, and the pose change model determines a pose of a vehicle at a next time according to a pose of the vehicle at a previous time; determining a final reversing reference trajectory of a towing vehicle in the target automobile train based on an initial control quantity sequence of a last trailer in the target automobile train, a pose of the last trailer at a first time, initial hinged angles of all vehicles in the target automobile train at the first time, the cascade model, and the reversing constraint, wherein the final reversing reference trajectory comprises a final control quantity sequence, a final hinged angle sequence, and a final pose sequence; tracking the final reversing reference trajectory of the towing vehicle to control the target automobile train to reverse, wherein the final reversing reference trajectory is taken as an input of a tracking system of the target automobile train, and the final reversing reference trajectory is tracked to realize the reversing control of the target automobile train; wherein the reversing constraint corresponding to the target automobile train is constructed, comprising: for each trailer in the target automobile train, determining a first critical hinged angle of the trailer based on a wheelbase of the trailer, a hitch point distance of a front vehicle of the trailer, and a maximum turning radius, and constructing an anti-folding constraint of the trailer according to the first critical hinged angle of the trailer; constructing an anti-folding constraint of the target automobile train based on the anti-folding constraints of all trailers in the target automobile train; wherein the hitch point distance is a distance from a corresponding hitch point to a center of a rear axle.

2. The method of claim 1, wherein, The reversing constraint further comprises a geometric collision constraint, and the construction of the reversing constraint corresponding to the target automobile train further comprises: for each trailer in the target automobile train, determining a second critical hinged angle of the trailer based on a hitch front distance of the trailer, a hitch point distance of a front vehicle of the trailer, and a width; for each trailer in the target automobile train, determining a third critical hinged angle of the trailer based on the hitch point distance of the front vehicle of the trailer, and the width and the hitch front distance of the trailer, and constructing a geometric collision constraint of the trailer according to the second critical hinged angle and the third critical hinged angle of the trailer; constructing a geometric collision constraint of the target automobile train based on the geometric collision constraints of all trailers in the target automobile train; wherein the hitch front distance is a distance from a corresponding hitch point to a front edge of a vehicle body.

3. The method of claim 1, wherein, The reversing constraint further comprises a stable domain constraint, and the construction of the reversing constraint corresponding to the target automobile train further comprises: For each trailer in the target automobile train, a fourth critical articulation angle of the trailer is determined based on a wheelbase of the trailer, and a sampled travel distance, a maximum articulation angle and a wheelbase of a previous vehicle of the trailer, and a feasible region constraint of the trailer is constructed according to the fourth critical articulation angle of the trailer; a stable region constraint of the target automobile train is constructed based on the stable region constraints of all trailers in the target automobile train; wherein the sampled travel distance is a distance traveled by the previous vehicle within a sampling step.

4. The method of claim 1, wherein, The reverse constraint further comprises a feasible region constraint, and the constructing the reverse constraint corresponding to the target automobile train further comprises: For each trailer in the target automobile train, a fifth critical articulation angle is determined, which is an articulation angle that makes a lateral velocity of the trailer equal to a longitudinal velocity during a process in which a previous vehicle of the trailer reverses at a critical steering angle, and a feasible region constraint of the trailer is constructed according to the fifth critical articulation angle of the trailer; a feasible region constraint of the target automobile train is constructed based on the feasible region constraints of all trailers in the target automobile train.

5. The method of claim 1, wherein, The determining the final reverse reference trajectory of the tractor in the target automobile train based on the initial control quantity sequence of the last trailer in the target automobile train, the initial pose of the last trailer at the first time, the initial articulation angles of all vehicles in the target automobile train at the first time, the cascaded model and the reverse constraint comprises: In a case where the target automobile train comprises a tractor and a single trailer, taking the first time as a current time, determining an initial control quantity of the tractor at the current time according to the motion inverse model, an initial control quantity of the trailer at the current time in the initial control quantity sequence of the trailer and an initial articulation angle of the trailer at the current time; determining an initial articulation angle of the trailer at a next time according to the articulation angle change model, the initial articulation angle of the trailer at the current time and the initial control quantity of the tractor at the current time; taking the next time as a new current time, returning to perform the step of determining the initial control quantity of the tractor at the current time according to the motion inverse model, the initial control quantity of the trailer at the current time in the initial control quantity sequence of the trailer and the initial articulation angle of the trailer at the current time, until the current time is the last time, to obtain an initial control quantity sequence of the tractor and an initial articulation angle sequence of the trailer; updating the initial articulation angle sequence of the trailer based on the reverse constraint, and determining a final control quantity sequence of the trailer according to the updated initial articulation angle sequence of the trailer; determining a final control quantity sequence of the tractor based on the final control quantity sequence of the trailer and the motion positive model, and determining a final articulation angle sequence of the tractor according to the initial articulation angle of the tractor at the first time, the final control quantity sequence of the tractor and the articulation angle change model; determining a final pose sequence of the tractor according to the initial pose of the tractor at the first time, the final control quantity sequence of the tractor and the pose change model.

6. The method of claim 5, wherein, The initial articulation angle sequence of the trailer is updated based on the reverse constraint, and a final control quantity sequence of the trailer is determined according to the updated initial articulation angle sequence of the trailer. It is judged whether there is a time point in the initial articulation angle sequence of the trailer at which a corresponding initial articulation angle violates the reverse constraint. For the time point at which the reverse constraint is violated, the initial articulation angle at the time point is updated based on a critical articulation angle in the reverse constraint, and an articulation angle change value at the time point is determined based on the updated initial articulation angle and the articulation angle change model, and a yaw angular velocity of the tractor at a previous time point of the time point is determined according to the articulation angle change value at the time point. A final control quantity of the tractor at the previous time point is determined based on the yaw angular velocity of the tractor at the previous time point, and a final control quantity of the trailer at the previous time point is determined based on the final control quantity of the tractor at the previous time point. The initial control quantity sequence of the trailer is updated based on the final control quantity of the trailer at the previous time point, and a final control quantity sequence of the trailer is obtained.

7. The method of claim 6, wherein, The initial control quantity sequence of the trailer is updated based on the final control quantity of the trailer at the previous time point, and a final control quantity sequence of the trailer is obtained. The initial control quantity at the previous time point in the initial control quantity sequence of the trailer is replaced by the final control quantity of the trailer at the previous time point. For each time point after the previous time point, a final control quantity of the trailer at each time point is determined based on the final control quantity of the trailer at the previous time point, the motion positive model, and the articulation angle change model, and a final control quantity sequence of the trailer is obtained.

8. The method of claim 1, wherein, The final reverse reference trajectory of the tractor is determined based on the initial control quantity sequence of the last trailer in the target automobile train, the pose of the last trailer at the first time point, the initial articulation angles of each vehicle in the target automobile train at the first time point, the cascade model, and the reverse constraint. A target optimization problem is constructed with the minimum control quantity deviation of the last trailer at each time point and the articulation angle deviation of each vehicle as the target, and with the reverse constraint, the motion positive model, and the articulation angle change model as the constraint conditions. The target optimization problem is solved based on the initial control quantity sequence of the last trailer in the target automobile train, the pose of the last trailer at the first time point, and the initial articulation angles of each vehicle at the first time point, and a final reverse reference trajectory of the last trailer is obtained. The final reverse reference trajectory of the tractor is determined based on the final reverse reference trajectory of the last trailer, the articulation angle change model, and the motion inverse model.

9. The method of claim 1, wherein, The final reverse reference trajectory of the tractor is tracked to control the target automobile train to reverse, including: The final control quantity sequence of the tractor is taken as the input of a tracking system of the target automobile train, so that the final reverse reference trajectory of the tractor is tracked by the tracking system. In the process that the tracking system tracks the final reverse reference trajectory of the tractor, the final reverse reference trajectory of the tractor is updated with the calculation result of the pre-constructed cost function as the minimum target and the reverse constraint as the constraint condition; The cost function is used to calculate the cost according to the control quantity deviation and the pose deviation.

10. The method of claim 1, wherein, Before determining the final reverse reference trajectory of the tractor in the target automobile train based on the initial control quantity sequence of the last trailer in the target automobile train, the pose of the last trailer at the first time, the initial articulation angle of each vehicle in the target automobile train at the first time, the cascade model and the reverse constraint, the method further comprises: determining whether there is a vehicle in the target automobile train that violates the reverse constraint at the first time, and if so, switching the target automobile train to forward mode driving until a preset stop driving condition is met to update the pose of the last trailer at the first time, the initial artication angle of each vehicle at the first time and the initial control quantity sequence of the last trailer.

11. A semi-trailer vehicle reversing device, characterised in that, Comprise: The construction module is configured to construct a cascade model corresponding to the target automobile train and a reverse constraint, wherein the cascade model comprises a motion inverse model, a motion positive model, an articulation angle change model and a pose change model, the reverse constraint comprises an anti-folding constraint, the motion inverse model determines the control quantity of a front vehicle according to the control quantity of a rear vehicle of two adjacent vehicles, the motion positive model determines the control quantity of a rear vehicle according to the control quantity of a front vehicle of two adjacent vehicles, the articulation angle change model determines the articulation angle of a vehicle at a next time according to the articulation angle of the vehicle at a previous time, the pose change model determines the pose of a vehicle at a next time according to the pose of the vehicle at a previous time, and the anti-folding constraint is used to limit the articulation angle of each vehicle in the target automobile train. The determination module is configured to determine the final reverse reference trajectory of the tractor in the target automobile train based on the initial control quantity sequence of the last trailer in the target automobile train, the pose of the last trailer at the first time, the initial articulation angle of each vehicle in the target automobile train at the first time, the cascade model and the reverse constraint, wherein the final reverse reference trajectory comprises a final control quantity sequence, a final articulation angle sequence and a final pose sequence. The tracking module is configured to track the final reverse reference trajectory of the tractor to control the reverse of the target automobile train, wherein the final reverse reference trajectory is taken as the input of a tracking system of the target automobile train, the final reverse reference trajectory is tracked, and the reverse control of the target automobile train is realized. The construction of the reverse constraint corresponding to the target automobile train comprises: For each trailer in the target automobile train, the first critical articulation angle of the trailer is determined based on the wheelbase of the trailer, the hitch point distance of the front vehicle of the trailer and the maximum turning radius, and the anti-folding constraint of the trailer is constructed according to the first critical articulation angle of the trailer. The anti-folding constraint of the target automobile train is constructed based on anti-folding constraints of all trailers in the target automobile train. The hitch point distance is a distance from the corresponding hitch point to the center of the rear axle.

12. An electronic device, comprising: The electronic device includes: one or more processors; a memory device for storing one or more programs; when the one or more programs are executed by the one or more processors, the one or more processors implement the method as claimed in any one of claims 1-10.

13. A computer readable storage medium having stored thereon a computer program, characterized in that, The program is executed by the processor to implement the method as claimed in any one of claims 1-10.

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