CN116300971B

CN116300971B - Traction sliding control method and device for civil aircraft, tractor and storage medium

Info

Publication number: CN116300971B
Application number: CN202310552995.1A
Authority: CN
Inventors: 秦嘉浩; 白杰; 张恩重; 张威
Original assignee: Civil Aviation University of China
Current assignee: Civil Aviation University of China
Priority date: 2023-05-17
Filing date: 2023-05-17
Publication date: 2023-09-01
Anticipated expiration: 2043-05-17
Also published as: CN116300971A

Abstract

The invention discloses a traction sliding control method and device of a civil aircraft, a tractor and a medium. The method comprises the following steps: controlling a wheel holding mechanism on a tractor to approach and accurately butt-joint a front landing gear of a target aircraft in a first-fast-then-slow mode, and planning a global planning path from a sliding starting point to a sliding end point after the butt-joint is completed; adopting a pre-established traction sliding controller to track and control the global planning path so as to enable the tractor to stably slide the traction target plane; during traction and taxiing, if an obstacle is detected to appear in front of a taxiing path and the obstacle cannot be avoided in a slow-down mode, a new global planning path is planned again according to the current taxiing position point, the obstacle information and the taxiing target point. The technical scheme of the embodiment of the invention ensures the accuracy, the rapidity and the safety of the automatic docking of the tractor and the airplane and improves the safety and the reliability of the tractor and the airplane in the combined sliding process.

Description

Traction sliding control method and device for civil aircraft, tractor and storage medium

Technical Field

The invention relates to the technical field of traction navigation of civil aircraft, in particular to a traction sliding control method and device of the civil aircraft, a tractor and a storage medium.

Background

The number of flights in China is increased gradually along with the development, and the speed of airports in the aircraft scheduling process is also required to be improved along with the increase of the number of flights. In order to ensure an increase in the working efficiency, it is necessary to use a tractor to pull the aircraft to glide to the target site, i.e. at the preparation point of the aircraft before takeoff.

In the related art, an unmanned rodless tractor can be adopted to automatically dock the wheel holding mechanism on the front landing gear of the aircraft, and after the wheel holding lifting is completed through docking, the tractor is used to pull the aircraft to slide from the parking apron to the preparation point before the aircraft takes off. One of the difficulties is the accuracy, rapidity and safety of the automatic docking process of the rodless tractor and the airplane; another difficulty is the safety and reliability of rodless tractors and aircraft during combined taxiing.

Disclosure of Invention

The embodiment of the invention provides a traction sliding control method and device of a civil aircraft, a tractor and a storage medium, so that after a wheel holding mechanism on the tractor is accurately abutted against a front landing gear of a target aircraft, the target aircraft is stably pulled by the tractor to slide to a sliding terminal point.

According to an aspect of the embodiment of the present invention, there is provided a traction taxiing control method of a civil aircraft, including:

controlling a wheel holding mechanism on a tractor to approach and accurately butt-joint a front landing gear of a target aircraft in a first-fast-then-slow mode, and planning a global planning path from a sliding starting point to a sliding end point after the butt-joint is completed;

adopting a pre-established traction sliding controller to track and control the global planning path so as to enable the tractor to stably slide the traction target plane;

during traction and sliding, if an obstacle appears in front of a sliding path, detecting whether the obstacle can be avoided in a slow-down and slow-running mode;

if not, re-planning a new global planning path according to the current sliding position point, the obstacle information and the sliding target point, and then returning to execute the operation of tracking and controlling the global planning path by adopting a pre-established traction sliding controller until the whole traction process is completed.

According to another aspect of the embodiment of the present invention, there is also provided a traction taxi control device of a civil aircraft, including:

the overall planning path planning module is used for controlling a wheel holding mechanism on the tractor to approach and accurately butt-joint the front landing gear of the target aircraft in a first-fast-then-slow mode, and planning an overall planning path from a sliding starting point to a sliding end point after the butt-joint is completed;

The track tracking control module is used for carrying out track tracking control on the global planning path by adopting a pre-established traction sliding controller so as to enable the tractor to stably drag the target aircraft to slide;

the avoidance detection module is used for detecting whether an obstacle can be avoided in a slow-down and slow-running mode if the obstacle appears in front of a sliding path in the traction sliding process;

and the path re-planning module is used for re-planning a new global planning path according to the current sliding position point, the obstacle information and the sliding target point if not, and then returning to execute the operation of tracking and controlling the global planning path by adopting a pre-established traction sliding controller until the whole traction process is completed.

According to another aspect of an embodiment of the present invention, there is also provided a tractor including:

at least one processor; and

a memory communicatively coupled to the at least one processor; wherein,

the memory stores a computer program executable by the at least one processor to enable the at least one processor to perform the method of controlling the towing taxiing of a civil aircraft according to any one of the embodiments of the invention.

According to another aspect of the embodiments of the present invention, there is also provided a computer readable storage medium storing computer instructions for implementing the method for controlling towing taxiing of a civil aircraft according to any one of the embodiments of the present invention when executed by a processor.

According to the technical scheme, the wheel holding mechanism on the tractor is controlled to approach and accurately butt-joint the front landing gear of the target aircraft in a first-fast-then-slow mode, and after the butt joint is completed, a global planning path from a sliding starting point to a sliding end point is planned; adopting a pre-established traction sliding controller to track and control the global planning path so as to enable the tractor to stably slide the traction target plane; during traction and sliding, if an obstacle appears in front of a sliding path, detecting whether the obstacle can be avoided in a slow-down and slow-running mode; if not, after a new global planning path is planned again according to the current sliding position point, the obstacle information and the sliding target point, the operation of carrying out track tracking control on the global planning path by adopting a pre-established traction sliding controller is carried out again until the technical means of the whole traction process is completed, the technical effect that the traction vehicle stably drags the target aircraft to the sliding end point after the wheel holding mechanism on the traction vehicle accurately butts the front landing gear of the target aircraft is realized, the accuracy, the rapidity and the safety of the automatic butt joint of the traction vehicle and the target aircraft are ensured, and the safety and the reliability of the traction vehicle and the aircraft in the combined sliding process are improved.

It should be understood that the description in this section is not intended to identify key or critical features of the embodiments of the invention or to delineate the scope of the invention. Other features of the present invention will become apparent from the description that follows.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for the description of the embodiments will be briefly described below, and it is apparent that the drawings in the following description are only some embodiments of the present invention, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

Fig. 1 is a flowchart of a method for controlling traction taxiing of a civil aircraft according to a first embodiment of the present invention;

fig. 2 is a flowchart of a method for controlling traction taxiing of a civil aircraft according to a second embodiment of the present invention;

FIG. 3 is a flow chart of one manner of calculating a target yaw angle of a tractor relative to a nose landing gear provided in accordance with a second embodiment of the present invention;

FIG. 4 is a front view of a tractor deflected by an angle α relative to the nose landing gear for which the teachings of the present invention are applicable;

FIG. 5 is a top view of a tractor deflected by an angle α relative to the nose landing gear for which the teachings of the present invention are applicable;

FIG. 6 is a schematic diagram of a dynamics model of a traction skidding system to which the solution of the embodiment of the present invention is applied;

fig. 7 is a block diagram of a traction taxiing control device for a civil aircraft according to a third embodiment of the present invention;

fig. 8 is a schematic diagram of a tractor according to a fourth embodiment of the present invention.

Detailed Description

In order that those skilled in the art will better understand the present invention, a technical solution in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in which it is apparent that the described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the present invention without making any inventive effort, shall fall within the scope of the present invention.

It should be noted that the terms "first," "second," and the like in the description and the claims of the present invention and the above figures are used for distinguishing between similar objects and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used may be interchanged where appropriate such that the embodiments of the invention described herein may be implemented in sequences other than those illustrated or otherwise described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

Example 1

Fig. 1 is a flowchart of a method for controlling traction and taxiing of a civil aircraft according to an embodiment of the present invention, where the method may be implemented by a traction and taxiing control device of a civil aircraft, which may be implemented in hardware and/or software, and may be generally configured in a tractor, and executed by a controller on the tractor, where a wheel-holding mechanism on the tractor is used to automatically dock a nose landing gear of a target aircraft to be towed, and after the wheel-holding is lifted by docking, the target aircraft is towed to a target position. As shown in fig. 1, the method includes:

s110, controlling a wheel holding mechanism on the tractor to approach and accurately butt-joint the front landing gear of the target aircraft in a first-fast-then-slow mode, and planning a global planning path from a sliding starting point to a sliding ending point after the butt-joint is completed.

In this embodiment, in order to improve the rapidity and accuracy of docking of a tractor (typically an unmanned, rodless tractor) to a target aircraft, a new implementation of controlling a wheel-holding mechanism on the tractor to approach and dock with the nose landing gear of the target aircraft step by step at least two speeds is proposed. Specifically, when the tractor is far from the target aircraft, the tractor can be controlled to quickly move towards the direction of the target aircraft. When the tractor is closer to the target aircraft, the tractor can be controlled to slowly move so as to accurately realize docking with the target aircraft.

Specifically, two or more groups of visual sensors can be arranged on the tractor in advance, and each group of visual sensors is used for detecting the relative distance and the relative position relation of the target aircraft with different distance. Correspondingly, the movement speed and the movement direction of the tractor can be flexibly set according to the detection results of the visual sensors in different groups, so that the effective consideration of the butting speed and the butting accuracy is realized.

It will be appreciated that the number of groups of visual sensors and the speed of movement selected for use at different distances may be set by those skilled in the art according to the actual circumstances, and this embodiment is not limited thereto.

After the wheel holding mechanism on the tractor is in butt joint with the front landing gear of the target aircraft, the position of the whole formed by the tractor and the target aircraft (hereinafter referred to as a traction sliding system) in an airport can be determined through the target aircraft or a positioning module arranged on the tractor to serve as a sliding starting point. Meanwhile, the taxiing end point, namely the preparation point of the target airplane before taking off, needs to be determined through an empty pipe instruction. After the taxi starting point and the taxi ending point are obtained, a global planned path of the traction taxi system from the taxi starting point to the taxi ending point can be planned by combining map data of an airport and a preset path planning algorithm.

When the global planning path is planned, constraint conditions such as least time consumption or least turning can be adopted for constraint, so that the global planning path meeting actual requirements is obtained.

And S120, performing track tracking control on the global planning path by adopting a pre-established traction taxiing controller so as to enable the tractor to stably drag the target aircraft to taxis.

After the global path planning is completed, the stable traction target aircraft of the tractor can be controlled to slide from the sliding starting point to the sliding ending point along the global planning path.

In this embodiment, in order to ensure that the tractor stably pulls the target aircraft to taxi, it is proposed to perform effective track following control during the whole taxi process. Specifically, a traction sliding controller is firstly constructed, and the cost control function and the constraint condition are set in the traction sliding controller, so that the optimal control quantity can be obtained in different control periods to effectively control the real-time speed and the real-time rotation angle of the tractor.

S130, in the traction sliding process, detecting whether an obstacle appears in front of a sliding path, if so, executing S140; otherwise, the process returns to S120 until the entire traction process is completed.

In this embodiment, in consideration of the dynamic change characteristics in the airport environment, it is necessary to detect an obstacle in front of the taxi path in real time. If no obstacle exists in front, the vehicle can continue to slide according to the original global planning path, and if the obstacle exists in front, the obstacle needs to be safely avoided, for example, the vehicle is decelerated, avoided or avoided by bypassing, and the like.

Further, considering that the implementation cost of deceleration avoidance is far lower than that of detour avoidance, in this embodiment, it is detected whether the traction sliding system can avoid the obstacle safely by the way of deceleration avoidance: if so, the vehicle can continue to slide after safely avoiding the obstacle by means of slowing down and slowing down on the basis of keeping the existing global planning route; if not, a new global planned route from the current taxi position point to the taxi end point needs to be planned again based on the information such as the position and the speed of the obstacle, so as to safely avoid the obstacle in a detour manner.

It will be appreciated that the operation of S130 needs to be performed in real time throughout the taxiing process until the tractor successfully tows the target aircraft to the taxiing endpoint.

S140, detecting whether the obstacle can be avoided in a slow-down mode: if yes, executing S150; otherwise, S160 is performed.

In this embodiment, it may be estimated whether the traction sliding system can avoid the obstacle in a slow-moving manner on the basis of maintaining the existing global planned route by combining the current position point, the movement speed and the movement direction of the obstacle, the movement speed and the movement direction of the traction sliding system, and the deceleration performance of the traction sliding system.

Specifically, a neural network model may be trained in advance, where the input of the neural network model is the current position point, the movement speed and the movement direction of the obstacle, and the parameters of the movement speed, the current position point, the deceleration performance parameter, the global planning route and the like of the traction sliding system are output as the recognition result of whether the traction sliding system can avoid the obstacle in a deceleration and slow-running mode.

And S150, after the deceleration avoidance strategy is executed, returning to the step S120 until the whole traction process is completed.

The deceleration avoidance strategy may define what time period and in what deceleration mode (e.g., specific braking time or throttle setting value) the tractor needs to perform deceleration processing, or what speed value the tractor needs to reduce the current speed to at what time point, etc.

Similarly, the deceleration avoidance strategy can be directly output by the neural network model, and can also be calculated in real time according to a preset calculation formula by combining the current position point, the movement speed and the movement direction of the obstacle, and parameters such as the movement speed, the current position point, the deceleration performance parameter, the global planning route and the like of the traction sliding system.

Specifically, after the deceleration avoidance strategy is executed to successfully avoid the obstacle, the speed of the traction sliding system can be gradually increased according to the preset acceleration processing strategy so as to continuously advance towards the sliding end point according to the normal sliding speed.

S160, re-planning a new global planning path according to the current sliding position point, the obstacle information and the sliding target point, and returning to execute S120 until the whole traction process is completed.

In this embodiment, if the obstacle cannot be successfully avoided only by means of deceleration, a new global planned route needs to be planned again, and a pre-established traction taxiing controller is adopted to continue track tracking control on the new planned global planned route, so that the tractor can stably drag the target aircraft.

It should be noted that, after determining that the obstacle cannot be avoided in a slow-down manner, first avoiding cost of the obstacle for avoiding the traction sliding system and second avoiding cost of the traction sliding system for avoiding the obstacle can be estimated first, if the second avoiding cost is far greater than the first avoiding cost, the air pipe center can be requested to prompt the obstacle to avoid, and a corresponding slow-down avoiding strategy is executed at the same time.

Example two

Fig. 2 is a flowchart of a traction and taxiing control method for a civil aircraft according to a second embodiment of the present invention, which is refined based on the foregoing embodiment, in this embodiment, a wheel holding mechanism on a tractor is controlled to approach and accurately dock a nose landing gear of a target aircraft in a fast-slow-after-fast manner, and after docking is completed, an operation of planning a global planned path from a taxiing start point to a taxiing end point is specified.

Accordingly, as shown in fig. 2, the method includes:

s210, acquiring a first nose landing gear image of a target aircraft in real time through a remote vision camera arranged on the tractor, and acquiring a first real-time distance and a relative position relation between the tractor and the nose landing gear according to the first nose landing gear image.

In this embodiment, two sets of vision sensors are provided on the tractor, with only one vision camera included in each set of vision sensors, to effect control of tractor movement through two speeds and docking of the target aircraft.

Optionally, a remote vision camera may be disposed near the centerline of the tractor roof, through which a relatively far-apart nose wheel (i.e., nose landing gear) is visually identified, and a first nose landing gear image is acquired.

After the first nose landing gear image is acquired, the image position and the occupied pixel size of the nose landing gear of the target aircraft can be acquired through an image recognition technology. After the information is acquired, the mapping relationship between the real space and the pixel space of the remote vision camera can be determined according to the camera calibration result for the remote vision camera and the installation position of the remote vision camera in the tractor. Further, the first real-time distance and the relative positional relationship between the tractor and the front landing gear can be identified based on the above-described mapping relationship.

S220, judging whether the first real-time distance is larger than a distance threshold value: if yes, executing S230; otherwise, S240 is performed.

In the present embodiment, the distance threshold value is used as a switching boundary of the tractor moving speed. When the distance between the tractor and the front landing gear is greater than the distance threshold, the tractor can quickly approach the front landing gear of the target aircraft at a larger speed, and when the distance between the tractor and the front landing gear is less than or equal to the distance threshold, the tractor can slowly approach the front landing gear of the target aircraft at a smaller speed so as to achieve both docking speed and docking accuracy.

The distance threshold may be preset according to an actual scene or a requirement of a docking speed or precision, which is not limited in this embodiment.

And S230, controlling a wheel holding mechanism on the tractor to move towards the nose landing gear at a first speed according to the relative position relation, and returning to the step S210.

After the relative positional relationship between the tractor and the nose landing gear is obtained, a wheel clasping mechanism on the tractor can be controlled to move towards the nose landing gear at a first speed based on the relative positional relationship so as to realize quick rough alignment.

S240, acquiring a second nose landing gear image of the target aircraft in real time through a near-distance vision camera arranged on the tractor, and calculating a target deflection angle of the tractor relative to the nose landing gear according to the second nose landing gear image.

Optionally, a near-distance vision camera can be fixedly installed on a front frame of the wheel holding mechanism on the central axis of the rodless tractor, and the near-distance vision camera can perform vision scanning on the environment under the working condition so as to quickly identify the position of the nose landing gear of the front aircraft.

Specifically, the model and technical parameters of the long-distance vision camera and the short-distance vision camera can be selected according to actual application scenes or application requirements. In general, the acquisition accuracy of near vision cameras is generally higher than that of far vision cameras.

When the distance between the wheel holding mechanism on the tractor and the nose landing gear of the target aircraft is very close, the relative position relationship between the wheel holding mechanism and the nose landing gear needs to be accurately determined, so that the wheel holding mechanism and the nose landing gear are accurately butted. That is, the target yaw angle of the tractor relative to the nose landing gear needs to be calculated.

In an alternative implementation of the present embodiment, as shown in fig. 3, the method for calculating the target yaw angle of the tractor with respect to the nose landing gear according to the second nose landing gear image may include:

s2401, identifying the outline of the nose landing gear in a second nose landing gear image, and identifying the deflection type of the tractor relative to the nose landing gear as left deflection or right deflection according to the characteristics of the outline of the nose landing gear.

In this embodiment, the nose landing gear profile may be identified in the second nose landing gear image by image recognition techniques. The left side of the hub is visible in the second nose gear image with the left offset angle, and the right side of the hub is visible in the second nose gear image with the right offset angle, so that the type of deflection of the tractor relative to the nose gear can be judged to be left offset or right offset based on the characteristics of the identified nose gear profile.

S2402, based on the nose landing gear profile, obtaining a transverse maximum dimension w', a longitudinal maximum dimension d, and a nose wheel width b of the nose wheel of the aircraft.

For convenience of explanation, a drawing to which the technical solution of the embodiment of the present invention is applied is shown in fig. 4Steering relative to nose landing gearAn angular elevation view, in figure 5, shows a tractor deflection relative to the nose landing gear for which the solution of the embodiment of the invention is applicable>A top view of the corner.

Specifically, the cross section of the aircraft tire is formed by complex circular arcs and line segments, and then a cylindrical model with a radius of R can be used for approximating a single tire, namely, the circular arc with the radius of R is used for fitting the tire radius. In general, the nose landing gear profile identified in the second nose landing gear image is shown in fig. 5, and therefore, the transverse maximum dimension w', the longitudinal maximum dimension d (i.e., the diameter of the front wheel tire), and the width b of the front wheel tire of the aircraft can be measured directly in fig. 5. In the example shown in FIG. 5, the angle of deflection of the tractor relative to the nose landing gear can be calculated by the following equations。

；

； wherein ,/>。

Obviously, for the purpose of calculation There is an unknown R that cannot be directly obtained from the nose landing gear profile.

S2403, determining a fixed proportional relation among the tire diameter d1, the tire width b1 and the tire arc radius R1 of the front wheel of the airplane according to the tire model of the target airplane.

It will be appreciated that a specified model of aircraft wheel is provided on a civil aircraft of a given model, and therefore, after the model of the target aircraft has been determined, the model of the wheel tyre of the target aircraft is also uniquely determined. After the model of the target aircraft's wheel tire has been determined, it is known that there is a fixed proportional relationship between its tire diameter d1 and tire width b1 and radius R1, which is still present in the nose landing gear profile identified in the second nose landing gear image, and thus a scaleable factor is introduced and />The method comprises the following steps: />；/>

S2404, calculating the deflection angle of the tractor relative to the nose landing gear according to the transverse maximum dimension w', the longitudinal maximum dimension d, the front wheel width b of the front wheel of the airplane and the fixed proportional relation.

By combining scaling factors and />Substituted into the aforesaid +.>The calculation formula of (2) can be used for obtaining the deflection angle of the tractor relative to the nose landing gear>。

Specifically, calculating the yaw angle of the tractor relative to the nose landing gear based on the transverse maximum dimension w', the longitudinal maximum dimension d, the front wheel width b of the front wheel of the aircraft, and the fixed proportional relationship may include:

According to the fixed proportion relation, a first proportion factor is obtainedAnd a second scale factor；

According to a first scale factorAnd a second scale factor->Calculating to obtain deflection adjustment factor->；

wherein ,；

according to the transverse maximum dimension w', the longitudinal maximum dimension d, the front wheel width b and the first scale factor of the front wheel of the aircraftSecond scale factor->Deflection adjustment factor->Calculating the yaw angle of the tractor relative to the nose landing gear>；

wherein ,。

s2405, using the combination of the deflection type and the deflection angle as a target deflection angle of the tractor with respect to the nose landing gear.

Wherein the target yaw angle describes the yaw angle of the tractor relative to the nose landing gear in a left-or right-hand manner.

S250, controlling a wheel holding mechanism on the tractor to approach and accurately butt-joint a nose landing gear of the target aircraft at a second speed according to the target deflection angle, wherein the first speed is greater than the second speed.

After the target deflection angle is accurately determined through the near vision camera, a wheel holding mechanism on the tractor can be controlled to approach and accurately butt-joint the nose landing gear of the target aircraft at a second speed.

Similarly, the first speed and the second speed can be set by a person skilled in the art according to the actual application scenario and the actual requirement, which is not limited in this embodiment.

It should be noted that, when the wheel holding mechanism on the tractor and the nose landing gear of the target aircraft realize automatic docking, the wheel holding mechanism can hold the front wheel of the aircraft up and lift the front wheel, and after receiving the next sliding instruction, the wheel holding mechanism drives the target aircraft to slide.

S260, determining a sliding starting point through a positioning module on the tractor, and identifying a sliding end point in the received empty pipe instruction.

S270, useAs a heuristic function, a global optimal path from the taxi start point to the taxi end point is planned by combining the taxi start point, the taxi end point and the airport map, and the global optimal path is used as a global planned path.

In this embodiment, the existing a-algorithm may be improved, so as to complete the planning of the global optimal path.

wherein ,is a heuristic factor, include->The value of (2) is determined by the size of the airport map; />The included angle between the vector formed by the current node and the starting point and the vector formed by the end point and the current node; />Is the included angle between the vector formed by the previous node and the current node and the vector formed by the next node and the current node; />Is a safety factor, is->The value of (2) is->Is of a certain size,/->，/>All are adjusting parameters, and are added with->The value of (2) is->Is of a certain size,/- >The value of (2) is->Is determined by the size of (a).

Specifically, coordinate information of a taxi start point and a taxi end point in an airport map is firstly obtained, and then a global optimal path is calculated based on the airport map and combined with a cost evaluation function f (n). The searching can be performed according to the cost evaluation function f (n), the point which is searched to be satisfied is used as a starting point of the next searching, the process is repeated until the sliding end point is found, and the points found in the searching process form an optimal path.

Alternatively, the cost evaluation function may be defined as:；

where f (n) is the cost evaluation function of the current node n, g (n) is the actual cost from the taxi start point to the current node n,for the cost of the current node to the target point, i.e. the heuristic function. In order to improve the calculation efficiency and the safety of the sliding process, the searching direction needs to be considered, the included angle information in the sliding process is constructed, and the obtained heuristic function is as follows:

。

wherein ,as a heuristic factor, determining the weight of the direction information in the traction and sliding process, wherein the value of the weight is determined according to the size of an actual map, and generally 5 is taken; />The angle between the vector of the current node and the start point and the vector of the end point and the current node reflects that the search direction points to the sliding end point. This- >The smaller the value, the more toward the end of the taxi the search is conducted; />Is the angle between the vector formed by the previous node and the current node and the vector formed by the next node and the current node, and is->The larger the included angle is, the higher the risk coefficient is; />As a safety factor, it determines the impact weight of the longitudinal angle of the tractor and the target aircraft on the taxi safety.

When (when)The angle is less than->When (I)>The value is 0, when->When (I)>Take a value of 5, whenWhen (I)>The value is 10, when->Time->The value is 20; />，/>Are all preset parameters, when->Little->When (I)>Is 0; when->Is greater than->When (I)>1 is shown in the specification; when->Less than->When (I)>Is 0; when->Greater thanWhen (I)>1.

And S280, performing track tracking control on the global planning path by adopting a pre-established traction taxiing controller so as to enable the tractor to stably drag the target aircraft to taxis.

Optionally, performing trajectory tracking control on the global planned path using a pre-established traction taxiing controller may include:

as shown in fig. 6, in the geodetic coordinate system XOY, the center of the front axle of the tractor is defined as a point a, the center of the rear axle is defined as a point B, the front-rear wheel distance of the tractor is L1, the hinge point of the tractor and the target aircraft is a point H, and the front wheel rotation angle of the tractor is The midpoint of the connecting line of the two main landing gears of the target aircraft is C point, the distance from the C point to the hinge point is L2, and the target aircraft is towedThe distance from the center B point of the rear axle to the hinge point H is La, and the yaw angle of the tractor is +.>The yaw angle of the target aircraft is +.>The articulation angle of the tractor and the target plane is +.>And obtaining a dynamic model schematic diagram of the traction sliding system.

To be used forFor the state quantity->Building an aircraft traction model for the control quantity:

； wherein ,/>Representing taking the derivative of Z;

according to the aircraft traction model, a state space expression of a four-degree-of-freedom linear error model is constructed and obtained:； wherein ,/>；

；/>；

；

Discretizing the state space expression of the four-degree-of-freedom linear error model, and obtaining a discretization model under a sampling period T as follows:

；

wherein ,，/>，/>；/>for the state quantity at the current time t0, +.>The state quantity at time t0+T.

Constructing control increments within each control periodAnd discrete state quantity +.>Controlling incrementsIs combined into a new state quantity +.>The new state space equation is obtained as follows:

；

wherein ,，/>，/>；

let Np be the predicted time domain step size, nc be the control time domain step size, and NcNp, the objective cost function is constructed as follows:

；

wherein ,is a reference value of the k+i moment predicted under the k moment; / >Is the actual value of the k+i moment output at the k moment; />The control increment of the k+i moment calculated under the k moment; />The weight coefficient of the relaxation factor is 1;

wherein ,；

；

；/>is a preset relaxation factor; wherein Q, R is a weight matrix, < + >>、/>、/>、/>、/> and />The values are all coefficients in the weight matrix, and the values are all 1;

based on the objective cost function and two constraints:

, and />Constructing and obtaining a traction sliding controller;

solving a target cost function in each control period based on the two constraint conditions through the traction sliding controller to obtain the following optimal control increment sequence:

；

and adding the first control increment in the optimal control increment sequence and the control quantity at the previous moment to serve as the control quantity input at the current moment through the traction sliding controller, repeating the above process in the next control period, performing online rolling optimization to obtain the actual control quantity at each moment, and finally realizing the track tracking control of the system.

S290, if an obstacle is detected to appear in front of a sliding path during traction sliding, whether the obstacle can be avoided in a slow-down and slow-running mode is detected.

In the embodiment, in the process of controlling the tractor and the target aircraft to travel according to the global planned path plan based on the optimal global path plan, the obstacle is perceived in real time so as to adjust the local path in real time to generate a smooth path.

In particular, the position of the aircraft and the tractor in the airport may be determined according to the positioning module, and the profile of the aircraft traction system may be constructed by storing the aircraft parameters and the tractor parameters in the module and combining the hinge angle information measured in the sensing module.

Then, whether an obstacle exists on the sliding path of the aircraft traction system can be detected in real time according to the sensing module, and when the obstacle exists, the processing judging module judges the safety risk by combining the speed and the size of the obstacle and the speed and the size of the aircraft traction system, and the slow deceleration mode is preferably selected for avoiding due to the characteristic of high turning danger coefficient of the aircraft traction system; when the airplane cannot avoid through the deceleration, the current node is taken as an initial node, the information of the obstacle is added into an airport map, and a new taxi path is planned again.

In an alternative implementation manner of the present embodiment, detecting whether the obstacle can be avoided in a slow-down mode may include:

acquiring the moving speed of the obstacle and the current traction sliding speed, and calculating the speed sum value of the moving speed and the traction sliding speed; if the speed sum value does not exceed a preset speed threshold value, determining that the obstacle can be avoided in a slow-down mode; otherwise, it is determined that the obstacle cannot be avoided in a slow-down mode.

In a specific example, when the sum of the moving speed of the obstacle and the current traction sliding speed is less than 50km/h, the obstacle can be avoided in a slow deceleration mode preferably; when the sum of the moving speed of the obstacle and the current traction sliding speed is greater than 50km/h, the deceleration may not be avoided, and at this time, the position coordinates and the speed of the obstacle need to be updated into the airport map.

And S2100, if not, re-planning a new global planning path according to the current sliding position point, the obstacle information and the sliding target point, and returning to execute the operation of tracking and controlling the track of the global planning path by adopting a pre-established traction sliding controller until the whole traction process is completed.

Example III

Fig. 7 is a schematic structural diagram of a traction environment control device for a civil aircraft according to a third embodiment of the present invention. As shown in fig. 7, the apparatus includes: a global planning path planning module 710, a trajectory tracking control module 720, a avoidance detection module 730, and a path re-planning module 740, wherein:

the global planning path planning module 710 is configured to control a wheel holding mechanism on the tractor to approach and accurately dock the nose landing gear of the target aircraft in a fast-then-slow manner, and plan a global planning path from a taxiing start point to a taxiing end point after docking is completed;

the track tracking control module 720 is configured to perform track tracking control on the global planned path by using a pre-established traction taxiing controller, so that the tractor stably tows the target aircraft for taxiing;

the avoidance detection module 730 is configured to detect, during traction and sliding, if an obstacle is detected to appear in front of a sliding path, whether the obstacle can be avoided in a slow-down manner;

and a path re-planning module 740, configured to, if not, re-plan a new global planned path according to the current sliding position point, the obstacle information and the sliding target point, and then return to executing the operation of performing track tracking control on the global planned path by using the pre-established traction sliding controller until the whole traction process is completed.

Based on the foregoing embodiments, the global planning path planning module 710 may specifically include:

the first image recognition unit is used for acquiring a first nose landing gear image of the target aircraft in real time through a remote vision camera arranged on the tractor, and acquiring a first real-time distance and a relative position relation between the tractor and the nose landing gear according to the first nose landing gear image;

the first speed moving unit is used for controlling the wheel holding mechanism on the tractor to move towards the front landing gear at a first speed according to the relative position relationship if the first real-time distance is larger than the distance threshold value;

the second image recognition unit is used for acquiring a second nose landing gear image of the target aircraft in real time through a near vision camera arranged on the tractor if the first real-time distance is smaller than or equal to the distance threshold value, and calculating a target deflection angle of the tractor relative to the nose landing gear according to the second nose landing gear image;

and the second speed moving unit is used for controlling a wheel holding mechanism on the tractor to approach and accurately butt-joint the nose landing gear of the target aircraft at a second speed according to the target deflection angle, wherein the first speed is higher than the second speed.

On the basis of the above embodiments, the second image recognition unit is specifically configured to:

identifying a nose landing gear contour in a second nose landing gear image, and identifying whether the deflection type of the tractor relative to the nose landing gear is left-hand deflection or right-hand deflection according to the characteristics of the nose landing gear contour;

acquiring a transverse maximum dimension w', a longitudinal maximum dimension d and a front wheel width b of the front wheel of the aircraft according to the nose landing gear profile;

according to the model of the tire of the target aircraft, determining a fixed proportional relationship among the tire diameter d1, the tire width b1 and the tire arc radius R1 of the front wheel of the aircraft;

calculating the deflection angle of the tractor relative to the nose landing gear according to the transverse maximum dimension w', the longitudinal maximum dimension d, the front wheel width b of the front wheel of the airplane and the fixed proportional relation;

the combination of the deflection type and the deflection angle is taken as a target deflection angle of the tractor relative to the nose landing gear.

On the basis of the above embodiments, the second image recognition unit is further specifically configured to:

According to a first scale factorAnd a second scale factor- >Calculating to obtain deflection adjustment factor->；

wherein ,；

wherein ,。

based on the above embodiments, the global planning path planning module 710 may be further specifically configured to:

determining a sliding starting point through a positioning module on the tractor, and identifying a sliding ending point in the received empty pipe instruction;

usingAs a heuristic function, planning a global optimal path from a sliding starting point to a sliding end point by combining the sliding starting point, the sliding end point and an airport map, and taking the global optimal path as a global planned path;

wherein ,is a heuristic factor, include->The value of (2) is determined by the size of the airport map; />The included angle between the vector formed by the current node and the starting point and the vector formed by the end point and the current node; />Is the vector formed by the previous node and the current node to follow the next oneIncluded angles between vectors formed by the individual nodes and the current node; />Is a safety factor, is->The value of (2) is->Is of a certain size,/->，/>All are adjusting parameters, and are added with->The value of (2) is- >Is of a certain size,/->The value of (2) is->Is determined by the size of (a).

Based on the above embodiments, the track following control module 720 may be specifically configured to:

in the geodetic coordinate system XOY, the front axle center of the tractor is defined as point A, the rear axle center is defined as point B, the front-rear wheel distance of the tractor is defined as L1, the hinging point of the tractor and the target plane is defined as point H, and the front wheel corner of the tractor is defined as point BThe midpoint of the connecting line of the two main landing gears of the target aircraft is a point C, the distance from the point C to the hinge point is L2, the distance from the center B of the rear axle of the tractor to the hinge point H is La, and the yaw angle of the tractor is +.>Target aircraftIs +.>The articulation angle of the tractor and the target plane is +.>；

； wherein ,/>Representing taking the derivative of Z;

；/>；

；

wherein ,，/>，/>；

constructing control increments within each control periodAnd discrete state quantity +.>Controlling increments Is combined into a new state quantity +.>The new state space equation is obtained as follows:

；

wherein ,，/>，/>；

；

wherein ,is a reference value of the k+i moment predicted under the k moment; />Is the actual value of the k+i moment output at the k moment; />The control increment of the k+i moment calculated under the k moment; />The weight coefficient of the relaxation factor is 1; />

wherein ,；

；

based on the objective cost function and two constraints:

, and />Constructing and obtaining a traction sliding controller;

；

Based on the foregoing embodiments, the avoidance detection module 730 may specifically be configured to:

acquiring the moving speed of the obstacle and the current traction sliding speed, and calculating the speed sum value of the moving speed and the traction sliding speed;

if the speed sum value does not exceed a preset speed threshold value, determining that the obstacle can be avoided in a slow-down mode; otherwise, it is determined that the obstacle cannot be avoided in a slow-down mode.

The traction sliding control device of the civil aircraft provided by the embodiment of the invention can execute the traction sliding control method of the civil aircraft provided by any embodiment of the invention, and has the corresponding functional modules and beneficial effects of the execution method.

Example IV

A schematic of the external shape of a tractor to which the fourth embodiment of the present invention is applied is shown in fig. 8. As shown in FIG. 8, the wheel-holding mechanism is 1-, the camera is 2-near vision, the gyroscope is 3-accelerometer, the controller is 4-, the range sensor is 5, 6-laser radar, the angle sensor is 7-and the camera is 8-far vision.

In this embodiment, the traction vehicle mainly includes a wheel holding mechanism, a controller, two vision cameras, and other sensors; the wheel holding mechanism is positioned near the center of the vehicle of the rodless tractor and is used for holding and lifting the front wheels of the aircraft.

The controller comprises a positioning module, a storage module, at least one processor and a motion controller; the positioning module is used for determining the position of the aircraft and the tractor in the airport, the storage module is used for storing the aircraft parameters and the tractor parameters, and the at least one processor is used for executing the method according to any embodiment of the invention, namely:

controlling a wheel holding mechanism on a tractor to approach and accurately butt-joint a front landing gear of a target aircraft in a first-fast-then-slow mode, and planning a global planning path from a sliding starting point to a sliding end point after the butt-joint is completed; adopting a pre-established traction sliding controller to track and control the global planning path so as to enable the tractor to stably slide the traction target plane; during traction and sliding, if an obstacle appears in front of a sliding path, detecting whether the obstacle can be avoided in a slow-down and slow-running mode; if not, re-planning a new global planning path according to the current sliding position point, the obstacle information and the sliding target point, and then returning to execute the operation of tracking and controlling the global planning path by adopting a pre-established traction sliding controller until the whole traction process is completed.

The motion controller is used for controlling the wheel holding mechanism to approach the nose landing gear quickly and slowly and controlling the direction and the throttle of the tractor in the traction and sliding process.

In the context of the present invention, a computer-readable storage medium may be a tangible medium that can contain, or store a computer program for use by or in connection with an instruction execution system, apparatus, or device. The computer readable storage medium may include, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. Alternatively, the computer readable storage medium may be a machine readable signal medium. More specific examples of a machine-readable storage medium would include an electrical connection based on 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 of the foregoing.

The above embodiments do not limit the scope of the present invention. It will be apparent to those skilled in the art that various modifications, combinations, sub-combinations and alternatives are possible, depending on design requirements and other factors. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of the present invention.

Claims

1. A method of controlling drag taxiing of a civil aircraft, comprising:

if not, re-planning a new global planning path according to the current sliding position point, the obstacle information and the sliding target point, and then returning to execute the operation of tracking and controlling the track of the global planning path by adopting a pre-established traction sliding controller until the whole traction process is completed;

If yes, executing a deceleration avoidance strategy, and then returning to execute the operation of performing track tracking control on the global planned path by adopting a pre-established traction sliding controller until the whole traction process is completed, wherein the deceleration avoidance strategy comprises the time when the tractor needs to perform deceleration processing in a deceleration mode, and the deceleration mode comprises a braking time or accelerator quantity setting value;

wherein detecting whether the obstacle can be avoided in a slow-down mode comprises:

inputting the current position point, the movement speed and the movement direction of the obstacle, the movement speed, the current position point, the deceleration performance parameters and the global planning route of the traction sliding system into a pre-trained neural network model, and outputting an identification result of whether the obstacle can be avoided in a deceleration slow-running mode by the neural network model;

the method further comprises the steps of:

if the recognition result is that the obstacle can not be avoided in a slow-down mode, calculating the first avoiding cost of the obstacle for avoiding the traction sliding system and the second avoiding cost of the traction sliding system for avoiding the obstacle, if the second avoiding cost is far greater than the first avoiding cost, requesting the hollow pipe center to prompt the obstacle to avoid, and executing a slow-down avoiding strategy.

2. The method of claim 1, wherein controlling the wheel-holding mechanism on the tractor to approach and accurately dock with the nose landing gear of the target aircraft in a quick-then-slow manner comprises:

acquiring a first nose landing gear image of a target aircraft in real time through a remote vision camera arranged on the tractor, and acquiring a first real-time distance and a relative position relationship between the tractor and the nose landing gear according to the first nose landing gear image;

if the first real-time distance is greater than the distance threshold, controlling a wheel holding mechanism on the tractor to move towards the nose landing gear at a first speed according to the relative position relationship;

if the first real-time distance is smaller than or equal to the distance threshold value, acquiring a second nose landing gear image of the target aircraft in real time through a near-distance vision camera arranged on the tractor, and calculating a target deflection angle of the tractor relative to the nose landing gear according to the second nose landing gear image;

and controlling a wheel holding mechanism on the tractor to approach and accurately butt-joint the nose landing gear of the target aircraft at a second speed according to the target deflection angle, wherein the first speed is greater than the second speed.

3. The method of claim 2, wherein calculating a target yaw angle of the tractor relative to the nose landing gear based on the second nose landing gear image comprises:

4. A method according to claim 3, wherein calculating the angle of deflection of the tractor relative to the nose landing gear from the transverse maximum dimension w', the longitudinal maximum dimension d, the front wheel width b of the front wheels of the aircraft and the fixed proportional relationship comprises:

according to the fixed proportion relation, a first proportion factor is obtainedAnd a second scale factor ；

wherein ,；

wherein ,。

5. the method of claim 1, wherein planning a global planned path from a taxi start point to a taxi end point comprises:

wherein ,is a heuristic factor, include->The value of (2) is determined by the size of the airport map; />The included angle between the vector formed by the current node and the starting point and the vector formed by the end point and the current node; />Is the included angle between the vector formed by the previous node and the current node and the vector formed by the next node and the current node; />Is a safety factor, is->The value of (2) is- >Is of a certain size,/->，/>All are adjusting parameters, and are added with->The value of (2) is->Is of a certain size,/->The value of (2) is->Is determined by the size of (a).

6. The method of claim 1, wherein performing trajectory tracking control on the global planned path using a pre-established traction taxi controller comprises:

in the geodetic coordinate system XOY, the front axle center of the tractor is defined as point A, the rear axle center is defined as point B, the front-rear wheel distance of the tractor is defined as L1, the hinging point of the tractor and the target plane is defined as point H, and the front wheel corner of the tractor is defined as point BThe midpoint of the connecting line of the two main landing gears of the target aircraft is a point C, the distance from the point C to the hinge point is L2, the distance from the center B of the rear axle of the tractor to the hinge point H is La, and the yaw angle of the tractor is +.>The yaw angle of the target aircraft is +.>The articulation angle of the tractor and the target plane is +.>；

； wherein ,/>Taking the derivative of the table on Z;

；/>；

；

wherein ,，/>，/>；

constructing control increments within each control periodAnd discrete state quantity +.>Controlling incrementsGroup(s)Synthesis of a New State quantity->The new state space equation is obtained as follows:

；

wherein ,，/>，/>；

let Np be the predicted time domain step size, nc be the control time domain step size, and NcNp, the objective cost function is constructed as follows:；

wherein ,is a reference value of the k+i moment predicted under the k moment; />Is the actual value of the k+i moment output at the k moment; />The control increment of the k+i moment calculated under the k moment; />The weight coefficient of the relaxation factor is 1;

wherein ,；

；

based on the objective cost function and two constraints:

, and />Constructing and obtaining a traction sliding controller;

by the tractionAnd the sliding guiding controller solves the objective cost function in each control period based on the two constraint conditions to obtain the following optimal control increment sequence:；

7. The method of claim 1, wherein detecting whether the obstacle can be avoided in a slow-down mode comprises:

8. A drag taxiing control device for a civil aircraft, comprising:

The path re-planning module is used for re-planning a new global planning path according to the current sliding position point, the obstacle information and the sliding target point if not, and then returning to execute the operation of tracking and controlling the global planning path by adopting a pre-established traction sliding controller until the whole traction process is completed;

the deceleration avoidance module is used for executing a deceleration avoidance strategy if yes, returning to execute the operation of performing track tracking control on the global planning path by adopting a pre-established traction sliding controller until the whole traction process is completed, wherein the deceleration avoidance strategy comprises when and in what deceleration mode the tractor needs to perform deceleration treatment, and the deceleration mode comprises a braking time or accelerator quantity setting value;

wherein, dodge detection module specifically is used for: inputting the current position point, the movement speed and the movement direction of the obstacle, the movement speed, the current position point, the deceleration performance parameters and the global planning route of the traction sliding system into a pre-trained neural network model, and outputting an identification result of whether the obstacle can be avoided in a deceleration slow-running mode by the neural network model;

The apparatus further comprises: an obstacle avoidance module for: if the recognition result is that the obstacle can not be avoided in a slow-down mode, calculating the first avoiding cost of the obstacle for avoiding the traction sliding system and the second avoiding cost of the traction sliding system for avoiding the obstacle, if the second avoiding cost is far greater than the first avoiding cost, requesting the hollow pipe center to prompt the obstacle to avoid, and executing a slow-down avoiding strategy.

9. A tractor, the tractor comprising:

at least one processor; and

a memory communicatively coupled to the at least one processor; wherein,

the memory stores a computer program executable by the at least one processor to enable the at least one processor to perform the method of controlling the towing taxi of a civil aircraft as claimed in any one of claims 1 to 7.

10. A computer readable storage medium storing computer instructions for causing a processor to perform the method of controlling the towing taxiing of a civil aircraft as claimed in any one of claims 1 to 7.