A wheel control system and method for a towbarless aircraft tractor

Abstract

The present invention discloses a wheel alignment control system and method for a rodless aircraft tractor, and relates to the technical field of tractor control. The control system comprises a data acquisition module, a data processing module, a data analysis module and an instruction execution module. The data acquisition module is used to acquire various information data before the tractor controls the wheels. The data processing module is used to process various information data. The data analysis module is used to analyze the processed information data to determine the driving trajectory of the tractor. The instruction execution module is used to execute the instructions of the driving trajectory analyzed by the data analysis unit. The present invention realizes wheel alignment by automatically controlling the movement of the tractor, so that there is no position or angle deviation between the wheel holding mechanism of the tractor and the front wheel of the aircraft, so that in the process of using the tractor to tow the aircraft, the force of the wheel holding mechanism is more uniform, the service life of the wheel holding mechanism is extended, and the safety of the aircraft towing process is improved.

Description

Technical Field

[0001] The invention relates to the technical field of tractor control, in particular to a wheel control system and method for an aircraft rodless tractor. Background Art

[0002] An aircraft tractor is a support equipment used to tow aircraft on the airport ground. It is divided into a tow bar tractor and a tow barless tractor. The tow barless tractor eliminates the towing bar connected to the aircraft and directly tows the aircraft by clamping the front wheels of the aircraft and lifting the front wheels of the aircraft through the wheel holding mechanism.

[0003] Before using a towbarless tractor to tow an aircraft, the tractor needs to be manually driven to align the wheel-holding mechanism of the towbarless tractor with the front wheels of the aircraft. During the wheel-holding process, if there is a position or angle deviation between the wheel-holding mechanism of the towbarless tractor and the front wheels of the aircraft, the force on the wheel-holding mechanism will be uneven. At the same time, when the tractor is used to tow and turn the aircraft, the force center of the wheel-holding mechanism will be offset, which not only affects the towing safety of the aircraft, but also reduces the service life of the wheel-holding mechanism.

[0004] Therefore, people are in urgent need of a wheel control system and method for an aircraft rodless tractor to solve the above-mentioned technical problems. Summary of the invention

[0005] The object of the present invention is to provide a wheel control system and method for a towbarless aircraft tractor to solve the problems in the prior art.

[0006] To achieve the above object, the present invention provides the following technical solution: a method for controlling wheels of an aircraft rodless tractor, the method comprising the following steps:

[0007] S1. Using a data acquisition module to acquire three-dimensional data of the front wheel of the aircraft, distance data between the front wheel of the aircraft and the wheel holding mechanism, and offset data between the front wheel of the aircraft and the lifting platform;

[0008] S2, using the model building unit to build a three-dimensional model of the front wheel of the aircraft, and importing the three-dimensional model of the front wheel of the aircraft into the digital three-dimensional model according to the distance data and the offset data;

[0009] S3, using the model mapping unit to project the digital three-dimensional model in S2 to obtain a two-dimensional model, and using the function building unit to build an offset function of the front wheel of the aircraft;

[0010] S4, analyzing the offset function using an offset analysis unit to determine the offset of the front wheel of the aircraft relative to the tractor;

[0011] S5. According to the analysis result of S4, a trajectory planning unit is used to plan the driving trajectory of the tractor and the front wheels of the aircraft during the wheel alignment process;

[0012] S6. Using the instruction execution module, the tractor is automatically controlled according to the driving trajectory planned in S5.

[0013] According to the above technical solution, in S1-S2, a three-dimensional laser scanner is used to obtain three-dimensional data of the front wheel of the aircraft, and a distance sensor is used to obtain distance data between the front wheel of the aircraft and the wheel holding mechanism and offset data between the front wheel of the aircraft and the lifting platform, and the distance sensors are arranged on both sides along the center point of the lifting platform;

[0014] A three-dimensional model of the aircraft's front wheel is established based on the three-dimensional data of the aircraft's front wheel, the relative position between the aircraft's front wheel and the lifting platform is determined using distance data and offset data, and the established three-dimensional model of the aircraft's front wheel is imported into the digital three-dimensional model.

[0015] According to the above technical solution, in S3, the model mapping unit is used to project the imported digitized three-dimensional model of the front wheel of the aircraft from top to bottom to obtain a digitized two-dimensional model, and a plane rectangular coordinate system is established on the digitized two-dimensional model with the center point of the lifting platform as the origin, and each coordinate point in the plane rectangular coordinate system is assigned a coordinate value;

[0016] Since the front wheel of the aircraft is composed of at least two tires, the center points A and B of at least two tires are assigned coordinate values ​​(X i , Y i ) and (X j , Y j );

[0017] Take any point C from the plane rectangular coordinate system, the coordinate value of C is (X k , Y k ), use the function establishment unit to calculate the distance between the center point A and point C and between the center point B and point C according to the following formula:

[0018]

[0019]

[0020] in, represents the distance between the center point A and point C, Indicates the distance between the center point B and point C;

[0021] when When , it indicates that point C is the point on the center axis of the aircraft's front wheel;

[0022] The function building unit obtains an offset function y=a*x+b according to the coordinate values ​​of at least two points C on the central axis of the front wheels of the aircraft, wherein a represents the slope of the offset function, and b represents the intersection point between the offset function and the Y axis of the plane rectangular coordinate system;

[0023] When b>0, it indicates that the front wheel of the aircraft is offset to the left relative to the lifting platform. The offset function at this time is y 正 =a 正 *x 正 +b 正 ;

[0024] When b < 0, it indicates that the front wheel of the aircraft is offset to the right relative to the lifting platform. The offset function at this time is y 负 =a 负 *x 负 +b 负 .

[0025] According to the above technical solution, in S4-S5, when b>0, in the process of analyzing the offset function by the offset analysis unit, the offset function y is respectively set to 正 =a 正 *x 正 +b 正 The y in 正 =0 and x 正 = 0, the coordinate value of the intersection between the offset function and the X-axis of the plane rectangular coordinate system is The coordinate value of the intersection point between the offset function and the Y axis of the plane rectangular coordinate system is (0, b 正 ),in

[0026] At this time, the offset analysis unit is used to calculate the offset angle α of the front wheel of the aircraft relative to the lifting platform. 正 Perform the calculation:

[0027] α 正 =arctan(-a 正 );

[0028] Then the offset angle of the aircraft's front wheel relative to the lifting platform is α 正 ;

[0029] The driving trajectory of the tractor planned by the trajectory planning unit is: driving along the positive semi-axis direction of the X-axis of the plane rectangular coordinate system After the distance, it is deflected α toward the positive semi-axis direction of the Y axis of the plane rectangular coordinate system 正 Angle, continue driving until the wheel-holding mechanism on the tractor completes the clamping of the aircraft's front wheels;

[0030] When b<0, in the process of analyzing the offset function using the offset analysis unit, the offset function y负 =a 负 *x 负 +b 负 The y in 负 =0 and x 负 = 0, the coordinate value of the intersection between the offset function and the X-axis of the plane rectangular coordinate system is The coordinate value of the intersection point between the offset function and the Y axis of the plane rectangular coordinate system is (0, b 负 ),in

[0031] At this time, the offset analysis unit is used to calculate the offset angle α of the front wheel of the aircraft relative to the lifting platform. 负 Perform the calculation:

[0032] α 负 =arctan(|a 负 |);

[0033] Then the offset angle of the aircraft's front wheel relative to the lifting platform is α 负 ;

[0034] At this point, it is necessary to determine the coordinate point where the tractor is offset on the offset function;

[0035] The minimum distance value collected by the distance sensor is L min ,Will Substitute the horizontal coordinate of the coordinate point where the tractor is offset on the offset function into the offset function y 负 =a 负 *x 负 +b 负 get Then the coordinate values ​​in the plane rectangular coordinate system are The coordinate point for the tractor to be offset;

[0036] At this time, the initial offset angle β of the tractor is calculated using the offset analysis unit:

[0037]

[0038] The trajectory of the tractor planned by the trajectory planning unit is: deflect the original position to the positive semi-axis direction of the Y axis of the plane rectangular coordinate system by an angle of β, and then move to the coordinate point Directions Distance, and then deflect to the negative semi-axis direction of the plane rectangular coordinate system Y (α 负 +β) angle and continue driving until the wheel-holding mechanism on the tractor completes the clamping of the aircraft's front wheels.

[0039] According to the above technical solution, in S6, according to the driving trajectory planned by the trajectory planning unit, the turning angle control unit is used to control the offset angle of the tractor during the automatic driving process, and the distance control unit is used to control the driving distance of the tractor during the automatic driving process.

[0040] A wheel control system for an aircraft rodless tractor, the system comprising a data acquisition module, a data processing module, a data analysis module and an instruction execution module;

[0041] The data acquisition module is used to acquire various information data before the tractor controls the wheels and during the automatic driving of the tractor, the data processing module is used to process the various information data acquired by the data acquisition module, the data analysis module is used to analyze the information data after data processing to determine the driving trajectory of the tractor and the front wheel of the aircraft during the wheel alignment process, and the instruction execution module is used to execute the control instruction of the tractor according to the driving trajectory obtained by the data analysis unit;

[0042] The output end of the data acquisition module is connected to the input end of the data processing module and the instruction execution module, the output end of the data processing module is connected to the input end of the data analysis module, and the output end of the data analysis module is connected to the input end of the instruction execution module.

[0043] According to the above technical solution, the data acquisition module includes a three-dimensional laser scanner, a distance sensor and an electromagnetic sensor;

[0044] The three-dimensional laser scanner is installed at the tail of the tractor, and is used to scan and obtain the three-dimensional data of the front wheel of the aircraft. There is no need to obtain the three-dimensional data of the entire front wheel of the aircraft, because the wheel holding mechanism of the tractor only needs to be aligned with the front part of the front wheel of the aircraft; the distance sensor is installed on the wheel holding mechanism of the tractor, and is used to obtain the distance data between the lifting platform and the front wheel of the aircraft. At the same time, it is also used to obtain the offset data between the front wheel of the aircraft and the lifting platform. On the one hand, when the tractor is controlled to automatically drive, the distance between the lifting platform and the front wheel of the aircraft is understood, and on the other hand, it is convenient to determine the distance and relative position between the front wheel of the aircraft and the lifting platform on the three-dimensional digital model; the electromagnetic sensor is installed on the steering wheel and tire spindle of the tractor, and is used to control the steering wheel rotation angle data and the driving distance data of the tractor during the automatic driving process of the tractor, so as to control the offset angle and driving distance of the tractor during the automatic driving process of the tractor.

[0045] According to the above technical solution, the data processing module includes a model building unit, a digital three-dimensional model, a model mapping unit and a function building unit;

[0046] The model building unit is used to build a three-dimensional model of the front wheel of the aircraft according to the three-dimensional data obtained by the three-dimensional laser scanner, so that the three-dimensional model of the front wheel of the aircraft can be imported into the digital three-dimensional model, so as to facilitate the digital processing of the entire wheel alignment process; the digital three-dimensional model is a three-dimensional model of the entire tractor established in advance, so as to facilitate the direct import of the three-dimensional model of the front part of the front wheel of the aircraft established by the model building unit, so that the tractor and the front wheel of the aircraft are located in the same three-dimensional model, and at the same time reduce the amount of data calculation required for the tractor to build the three-dimensional model; the model mapping unit is used to project the digital three-dimensional model from top to bottom to obtain a digital two-dimensional model, so as to achieve The dimension of the digital three-dimensional model is reduced by performing a latitude reduction process after establishing the digital three-dimensional model, so that the relative position relationship between the tractor and the front wheel of the aircraft can be accurately determined. The model mapping unit also establishes a plane rectangular coordinate system on the digital two-dimensional model with the center point of the lifting platform as the origin, and assigns a coordinate value to each point in the digital two-dimensional model, so as to facilitate the digital analysis and processing of the driving trajectory of the tractor, so that the wheel alignment process is more accurate; the function establishment unit is used to establish an offset function according to at least two coordinate points on the center axis of the front wheel of the aircraft, so as to realize the digital analysis and processing of the driving trajectory of the tractor and improve the accuracy of the wheel alignment;

[0047] The output end of the three-dimensional laser scanner is connected to the input end of the model building unit, the output ends of the model building unit and the distance sensor are connected to the input end of the digitized three-dimensional model, and the output end of the function building unit is connected to the input end of the data analysis module.

[0048] According to the above technical solution, the data analysis module includes a trajectory planning unit of an offset analysis unit;

[0049] The offset analysis unit determines the offset of the front wheel of the aircraft relative to the tractor by calculating the coordinate value of the intersection between the offset function and the plane rectangular coordinate system, so as to plan the driving trajectory of the tractor according to the offset; the trajectory planning unit is used to plan the driving trajectory of the tractor according to the offset of the front wheel of the aircraft relative to the tractor, so that the tractor moves according to the predetermined trajectory and realizes accurate wheel alignment with the front wheel of the aircraft;

[0050] The output end of the function establishment unit is connected to the input end of the offset analysis unit, the output end of the offset analysis unit is connected to the input end of the trajectory planning unit, and the output end of the trajectory planning unit is connected to the input end of the instruction execution module.

[0051] According to the above technical solution, the instruction execution module includes a turning angle control unit and a distance control unit;

[0052] The turning angle control unit is used to control the deviation angle of the tractor according to the driving trajectory planned by the trajectory planning unit during the automatic driving of the tractor; the distance control unit is used to control the driving distance of the tractor according to the driving trajectory planned by the trajectory planning unit during the automatic driving of the tractor;

[0053] The output ends of the trajectory planning unit and the electromagnetic sensor are connected to the input ends of the turning angle control unit and the distance control unit.

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

[0055] 1. The present invention does not align the wheels between the tractor and the front wheels of the aircraft based on the experience of the tractor, but achieves the alignment by automatically controlling the movement of the tractor, so that there will be no position or angle deviation between the wheel holding mechanism of the tractor and the front wheels of the aircraft. In the process of towing the aircraft by the tractor, the force on the wheel holding mechanism is more uniform, which prolongs the service life of the wheel holding mechanism and improves the safety of the aircraft during towing.

[0056] 2. The present invention processes and analyzes various information data before the alignment of the tractor and the front wheels of the aircraft in a digital manner, so that the alignment of the tractor and the front wheels of the aircraft can be achieved more accurately. In addition, automatic driving control is adopted in the whole process to avoid errors and operational mistakes caused by human operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1 It is a schematic diagram of the module composition of a wheel control system of a towbarless aircraft tractor according to the present invention;

[0058] Figure 2 It is a schematic diagram of the primary connection relationship of a wheel control system of a towbarless aircraft tractor according to the present invention;

[0059] Figure 3 It is a schematic diagram of the secondary connection relationship of a wheel control system of a towbarless aircraft tractor according to the present invention;

[0060] Figure 4 A schematic flow chart of the steps of a method for controlling wheels of a towbarless aircraft tractor according to the present invention;

[0061] Figure 5 It is a schematic diagram of a digital two-dimensional model of a first situation of a wheel control method of a towbarless tractor for an aircraft according to the present invention;

[0062] Figure 6 The figure is a schematic diagram of a digital two-dimensional model of a second situation of a wheel control method of a towbarless tractor for an aircraft according to the present invention. DETAILED DESCRIPTION

[0063] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0064] like Figures 4 to 6 As shown, the present invention provides the following technical solution, a method for controlling wheels of an aircraft rodless tractor, the method comprising the following steps:

[0065] S1. Using a data acquisition module to acquire three-dimensional data of the front wheel of the aircraft, distance data between the front wheel of the aircraft and the wheel holding mechanism, and offset data between the front wheel of the aircraft and the lifting platform;

[0066] S2, using the model building unit to build a three-dimensional model of the front wheel of the aircraft, and importing the three-dimensional model of the front wheel of the aircraft into the digital three-dimensional model according to the distance data and the offset data;

[0067] S3, using the model mapping unit to project the digital three-dimensional model in S2 to obtain a two-dimensional model, and using the function building unit to build an offset function of the front wheel of the aircraft;

[0068] S4, analyzing the offset function using an offset analysis unit to determine the offset of the front wheel of the aircraft relative to the tractor;

[0069] S5. According to the analysis result of S4, a trajectory planning unit is used to plan the driving trajectory of the tractor and the front wheels of the aircraft during the wheel alignment process;

[0070] S6. Using the instruction execution module, the tractor is automatically controlled according to the driving trajectory planned in S5.

[0071] In S1-S2, a three-dimensional laser scanner is used to acquire three-dimensional data of the front wheel of the aircraft, and a distance sensor is used to acquire distance data between the front wheel of the aircraft and the wheel-holding mechanism and offset data between the front wheel of the aircraft and the lifting platform. The distance sensors are arranged on both sides along the center point of the lifting platform. The wheel-holding mechanism refers to a mechanism on the rodless tractor that clamps the front wheel of the aircraft. The lifting platform is a part of the wheel-holding mechanism. After the wheel-holding mechanism fixes the front wheel of the aircraft, the lifting mechanism is used to lift the front wheel of the aircraft to lift the front wheel of the aircraft off the ground.

[0072] A three-dimensional model of the aircraft's front wheel is established based on the three-dimensional data of the aircraft's front wheel, the relative position between the aircraft's front wheel and the lifting platform is determined using distance data and offset data, and the established three-dimensional model of the aircraft's front wheel is imported into the digital three-dimensional model.

[0073] Because a plurality of parallel distance sensors are embedded and installed on the lifting platform, the front wheel of the aircraft is composed of at least two tires, and there is a certain distance between the two tires. The distance between each two adjacent distance sensors is smaller than the width of the front wheel tire of the aircraft. Therefore, at least three distance sensors will collect the distance between the lifting platform and the front wheel of the aircraft. The difference between the distance data collected by the two adjacent distance sensors can be used to analyze and calculate the offset data of the aircraft tire. This solution belongs to the conventional technical means of those skilled in the art, and therefore, it will not be described in detail in the present invention.

[0074] In S3, the model mapping unit is used to project the imported digital three-dimensional model of the front wheel of the aircraft from top to bottom to obtain a digital two-dimensional model, and a plane rectangular coordinate system is established on the digital two-dimensional model with the center point of the lifting platform as the origin, and each coordinate point in the plane rectangular coordinate system is assigned a coordinate value. Because in the actual wheel control of the tractor and the front wheel of the aircraft, only the relative position change on the plane needs to be considered, and there is no need to consider the height change between the wheel holding mechanism and the front wheel of the aircraft. Therefore, it is necessary to reduce the dimension of the digital three-dimensional model for easy analysis;

[0075] Since the front wheel of the aircraft is composed of at least two tires, the center points A and B of at least two tires are assigned coordinate values ​​(X i , Y i ) and (X j , Y j );

[0076] Take any point C from the plane rectangular coordinate system, the coordinate value of C is (X k , Y k ), use the function establishment unit to calculate the distance between the center point A and point C and between the center point B and point C according to the following formula:

[0077]

[0078]

[0079] in, represents the distance between the center point A and point C, Indicates the distance between the center point B and point C;

[0080] when When , it indicates that point C is the point on the center axis of the aircraft's front wheel;

[0081] The function building unit obtains an offset function y=a*x+b according to the coordinate values ​​of at least two points C on the central axis of the front wheels of the aircraft, wherein a represents the slope of the offset function, and b represents the intersection point between the offset function and the Y axis of the plane rectangular coordinate system;

[0082] When b>0, it indicates that the front wheel of the aircraft is offset to the left relative to the lifting platform. The offset function at this time is y 正 =a 正 *x 正 +b 正 ;

[0083] When b < 0, it indicates that the front wheel of the aircraft is offset to the right relative to the lifting platform. The offset function at this time is y 负 =a 负 *x 负 +b 负 .

[0084] In S4-S5, when b>0, in the process of analyzing the offset function using the offset analysis unit, the offset function y is respectively set to 正 =a 正 *x 正 +b 正 The y in 正 =0 and x 正 = 0, the coordinate value of the intersection between the offset function and the X-axis of the plane rectangular coordinate system is The coordinate value of the intersection point between the offset function and the Y axis of the plane rectangular coordinate system is (0, b 正 ),in

[0085] At this time, the offset analysis unit is used to calculate the offset angle α of the front wheel of the aircraft relative to the lifting platform. 正 Perform the calculation:

[0086] α 正 =arctan(-a 正 )

[0087] Then the offset angle of the aircraft's front wheel relative to the lifting platform is α 正 ;

[0088] The driving trajectory of the tractor planned by the trajectory planning unit is: driving along the positive semi-axis direction of the X-axis of the plane rectangular coordinate system After the distance, it is deflected α toward the positive semi-axis direction of the Y axis of the plane rectangular coordinate system 正 Angle, continue driving until the wheel-holding mechanism on the tractor completes the clamping of the aircraft's front wheels;

[0089] When b<0, in the process of analyzing the offset function using the offset analysis unit, the offset function y 负 =a 负 *X 负 +b 负 The y in 负 =0 and x 负= 0, the coordinate value of the intersection between the offset function and the X-axis of the plane rectangular coordinate system is The coordinate value of the intersection point between the offset function and the Y axis of the plane rectangular coordinate system is (0, b 负 ),in

[0090] At this time, the offset analysis unit is used to calculate the offset angle α of the front wheel of the aircraft relative to the lifting platform. 负 Perform the calculation:

[0091] α 负 =arctan(|a 负 |);

[0092] Then the offset angle of the aircraft's front wheel relative to the lifting platform is α 负 ;

[0093] At this point, it is necessary to determine the coordinate point where the tractor is offset on the offset function;

[0094] The minimum distance value collected by the distance sensor is L min ,Will Substitute the horizontal coordinate of the coordinate point where the tractor is offset on the offset function into the offset function y 负 =a 负 Technique 负 +b 负 get Then the coordinate values ​​in the plane rectangular coordinate system are The coordinate point for the tractor to be offset;

[0095] Here, half of the minimum value between the front wheel of the aircraft and the lifting platform is used as the horizontal coordinate of the coordinate point where the tractor is offset on the offset function. The purpose is to ensure that the tractor is traveling directly toward the front wheel of the aircraft for at least a certain distance, so as to avoid the distance between the offset point of the tractor on the offset function and the front wheel of the aircraft being too small, resulting in deviation when the front wheel of the aircraft and the wheel holding mechanism of the tractor are aligned, thus affecting the normal towing of the aircraft;

[0096] At this time, the initial offset angle β of the tractor is calculated using the offset analysis unit:

[0097]

[0098] The trajectory of the tractor planned by the trajectory planning unit is: deflect the original position to the positive semi-axis direction of the Y axis of the plane rectangular coordinate system by an angle of β, and then move to the coordinate point Directions Distance, and then deflect to the negative semi-axis direction of the plane rectangular coordinate system Y (α 负+β) angle and continue driving until the wheel-holding mechanism on the tractor completes the clamping of the aircraft's front wheels.

[0099] In S6, according to the driving trajectory planned by the trajectory planning unit, the turning angle control unit is used to control the offset angle of the tractor during the automatic driving process, and the distance control unit is used to control the driving distance of the tractor during the automatic driving process.

[0100] like Figure 1 to Figure 3 As shown, a wheel control system for a towbarless aircraft tractor includes a data acquisition module, a data processing module, a data analysis module and an instruction execution module;

[0101] The data acquisition module is used to acquire various information data before the tractor controls the wheels and during the automatic driving of the tractor, the data processing module is used to process the various information data acquired by the data acquisition module, the data analysis module is used to analyze the information data after data processing to determine the driving trajectory of the tractor and the front wheel of the aircraft during the wheel alignment process, and the instruction execution module is used to execute the control instruction of the tractor according to the driving trajectory obtained by the data analysis unit;

[0102] The output end of the data acquisition module is connected to the input end of the data processing module and the instruction execution module, the output end of the data processing module is connected to the input end of the data analysis module, and the output end of the data analysis module is connected to the input end of the instruction execution module.

[0103] The data acquisition module includes a three-dimensional laser scanner, a distance sensor and an electromagnetic sensor;

[0104] The 3D laser scanner is installed at the rear of the tractor, specifically at both sides of the rear of the tractor, and is used to scan and acquire the 3D data of the front wheels of the aircraft, specifically to scan the 3D data from the left front and right front of the front wheels of the aircraft, and there is no need to acquire the 3D data of the entire front wheels of the aircraft, because the wheel holding mechanism of the tractor only needs to be aligned with the front of the front wheels of the aircraft; the distance sensor is installed on the wheel holding mechanism of the tractor, specifically embedded in the lifting platform of the wheel holding mechanism, and is used to acquire the distance data between the lifting platform and the front wheels of the aircraft, and at the same time, it is also used to acquire the offset data between the front wheels of the aircraft and the lifting platform, so that on the one hand, the 3D data of the front wheels of the aircraft can be acquired when the tractor is under the control of the tractor. When the tractor is controlling the automatic driving, the distance between the lifting platform and the front wheel of the aircraft is understood. On the other hand, it is convenient to determine the distance and relative position between the front wheel of the aircraft and the lifting platform on the three-dimensional digital model; the electromagnetic sensor is installed on the steering wheel and tire spindle of the tractor, and is used to control the collection of steering wheel rotation angle data and tractor travel distance data during the automatic driving process of the tractor, and convert the steering wheel rotation angle into the deflection angle of the tractor through the angle control algorithm, and convert the number of tire rotation circles into the travel distance of the tractor through the distance control algorithm, so as to control the deviation angle and travel distance of the tractor during the automatic driving process of the tractor.

[0105] The data processing module includes a model building unit, a digital three-dimensional model, a model mapping unit and a function building unit;

[0106] The model building unit is used to build a three-dimensional model of the front wheel of the aircraft according to the three-dimensional data obtained by the three-dimensional laser scanner. Specifically, a three-dimensional model of the front part of the front wheel of the aircraft is built, so that the three-dimensional model of the front wheel of the aircraft can be imported into the digital three-dimensional model, so as to facilitate the digital processing of the entire wheel alignment process; the digital three-dimensional model is a three-dimensional model of the entire tractor built in advance, so as to directly import the three-dimensional model of the front part of the front wheel of the aircraft built by the model building unit, so that the tractor and the front wheel of the aircraft are located in the same three-dimensional model, and at the same time reduce the amount of data calculation required for the tractor to build the three-dimensional model; the model mapping unit is used to project the digital three-dimensional model from top to bottom to obtain a digital The digital two-dimensional model is used to reduce the dimension of the digital three-dimensional model. After the digital three-dimensional model is established, the dimensionality reduction processing is performed, so that the relative position relationship between the tractor and the front wheel of the aircraft can be accurately determined. The model mapping unit also establishes a plane rectangular coordinate system on the digital two-dimensional model with the center point of the lifting platform as the origin, and assigns a coordinate value to each point in the digital two-dimensional model, so as to facilitate the digital analysis and processing of the driving trajectory of the tractor, so that the wheel alignment process is more accurate; the function establishment unit is used to establish an offset function according to at least two coordinate points on the center axis of the front wheel of the aircraft, so as to realize the digital analysis and processing of the driving trajectory of the tractor and improve the accuracy of the wheel alignment;

[0107] The output end of the three-dimensional laser scanner is connected to the input end of the model building unit, the output ends of the model building unit and the distance sensor are connected to the input end of the digitized three-dimensional model, and the output end of the function building unit is connected to the input end of the data analysis module.

[0108] The data analysis module includes a trajectory planning unit of an offset analysis unit;

[0109] The offset analysis unit determines the offset of the front wheel of the aircraft relative to the tractor by calculating the coordinate value of the intersection between the offset function and the plane rectangular coordinate system, and the offset includes an offset direction and an offset angle, so as to plan the driving trajectory of the tractor according to the offset; the trajectory planning unit is used to plan the driving trajectory of the tractor according to the offset of the front wheel of the aircraft relative to the tractor, so that the tractor moves according to the predetermined trajectory and realizes accurate wheel alignment with the front wheel of the aircraft;

[0110] The output end of the function establishment unit is connected to the input end of the offset analysis unit, the output end of the offset analysis unit is connected to the input end of the trajectory planning unit, and the output end of the trajectory planning unit is connected to the input end of the instruction execution module.

[0111] The instruction execution module includes a turning angle control unit and a distance control unit;

[0112] The turning angle control unit is used to control the deviation angle of the tractor according to the driving trajectory planned by the trajectory planning unit during the automatic driving of the tractor; the distance control unit is used to control the driving distance of the tractor according to the driving trajectory planned by the trajectory planning unit during the automatic driving of the tractor;

[0113] The output ends of the trajectory planning unit and the electromagnetic sensor are connected to the input ends of the turning angle control unit and the distance control unit.

[0114] Embodiment 1:

[0115] Since the front wheel of the aircraft is composed of at least two tires, the center points A and B of at least two tires are assigned coordinate values ​​(X i , Y i ) and (X j , Y j );

[0116] Take any point C from the plane rectangular coordinate system, the coordinate value of C is (X k , Y k ), use the function establishment unit to calculate the distance between the center point A and point C and between the center point B and point C according to the following formula:

[0117]

[0118]

[0119] in, represents the distance between the center point A and point C, Indicates the distance between the center point B and point C;

[0120] when When , it indicates that point C is the point on the center axis of the aircraft's front wheel;

[0121] The function building unit obtains an offset function y=a*x+b according to the coordinate values ​​of at least two points C on the central axis of the front wheels of the aircraft, wherein a represents the slope of the offset function, and b represents the intersection point between the offset function and the Y axis of the plane rectangular coordinate system; for example, the two points C are respectively (1, 1.35) and (2, 1.2);

[0122] b>0, indicating that the front wheel of the aircraft is offset to the left relative to the lifting platform. The offset function at this time is y 正 =a 正 *x 正 +b 正 =-0.15*x 正 +15;

[0123] In the process of analyzing the offset function using the offset analysis unit, the offset function y is respectively set to 正 =a 正 *x 正 +b 正 The y in 正 =0 and x 正 = 0, the coordinate value of the intersection between the offset function and the X-axis of the plane rectangular coordinate system is The coordinate value of the intersection point between the offset function and the Y axis of the plane rectangular coordinate system is (0, b 正 ) = (0, 1.5);

[0124] At this time, the offset analysis unit is used to calculate the offset angle α of the front wheel of the aircraft relative to the lifting platform. 正 Perform the calculation:

[0125] α 正 =arctan(-a 正 )=8.53°;

[0126] Then the offset angle of the aircraft's front wheel relative to the lifting platform is α 正 =8.53°;

[0127] The driving trajectory of the tractor planned by the trajectory planning unit is: driving along the positive semi-axis direction of the X-axis of the plane rectangular coordinate system After the distance, it is deflected α toward the positive semi-axis direction of the Y axis of the plane rectangular coordinate system 正 =8.53° angle, and continue driving until the wheel-holding mechanism on the tractor completes the clamping of the aircraft's front wheels.

[0128] Embodiment 2:

[0129] Since the front wheel of the aircraft is composed of at least two tires, the center points A and B of at least two tires are assigned coordinate values ​​(X i , Y i ) and (X j , Y j );

[0130] Take any point C from the plane rectangular coordinate system, the coordinate value of C is (X k , Y k ), use the function establishment unit to calculate the distance between the center point A and point C and between the center point B and point C according to the following formula:

[0131]

[0132]

[0133] in, represents the distance between the center point A and point C, Indicates the distance between the center point B and point C;

[0134] when When , it indicates that point C is the point on the center axis of the aircraft's front wheel;

[0135] The function building unit obtains an offset function y=a*x+b according to the coordinate values ​​of at least two points C on the central axis of the front wheels of the aircraft, wherein a represents the slope of the offset function, and b represents the intersection between the offset function and the Y axis of the plane rectangular coordinate system; for example, the two points C are respectively (3, -15.95) and (2, -16.3);

[0136] b<0, indicating that the front wheel of the aircraft is offset to the right relative to the lifting platform. The offset function at this time is:

[0137] y 负 =a 负 *x 负 +b 负 =0.35*x 负 +(-17

[0138] In the process of analyzing the offset function using the offset analysis unit, the offset function y is respectively set to 负 =a 负 *x 负 +b 负 The y in 负 =0 and x 负 = 0, the coordinate value of the intersection between the offset function and the X-axis of the plane rectangular coordinate system is The coordinate value of the intersection point between the offset function and the Y axis of the plane rectangular coordinate system is (0, b 负 ) = (0, -17);

[0139] At this time, the offset analysis unit is used to calculate the offset angle α of the front wheel of the aircraft relative to the lifting platform. 负 Perform the calculation:

[0140] α 负 =arctan(|a 负 |)=19.29°;

[0141] Then the offset angle of the aircraft's front wheel relative to the lifting platform is α 负 =19.29°;

[0142] At this point, it is necessary to determine the coordinate point where the tractor is offset on the offset function;

[0143] The minimum distance value collected by the distance sensor is L min =30, Substitute the horizontal coordinate of the coordinate point where the tractor is offset on the offset function into the offset function y 负 =a 负 *x 负 +b 负 get Then the coordinate values ​​in the plane rectangular coordinate system are The coordinate point for the tractor to be offset;

[0144] At this time, the initial offset angle β of the tractor is calculated using the offset analysis unit:

[0145]

[0146] The trajectory of the tractor planned by the trajectory planning unit is: deflect β = 37.95° in the positive semi-axis direction of the Y axis of the plane rectangular coordinate system, and then move to the coordinate point Directions Distance, and then deflect to the negative semi-axis direction of the plane rectangular coordinate system Y (α 负 +β)=57.24°, and continue driving until the wheel-holding mechanism on the tractor completes the clamping of the aircraft's front wheels.

[0147] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

Claims

1. A method for controlling wheels of a towbarless aircraft tractor, characterized in that: The method comprises the following steps: S1. Using a data acquisition module to acquire three-dimensional data of the front wheel of the aircraft, distance data between the front wheel of the aircraft and the wheel holding mechanism, and offset data between the front wheel of the aircraft and the lifting platform; S2, using the model building unit to build a three-dimensional model of the front wheel of the aircraft, and importing the three-dimensional model of the front wheel of the aircraft into the digital three-dimensional model according to the distance data and the offset data; S3, using the model mapping unit to project the digital three-dimensional model in S2 to obtain a two-dimensional model, and using the function building unit to build an offset function of the front wheel of the aircraft; S4, analyzing the offset function using an offset analysis unit to determine the offset of the front wheel of the aircraft relative to the tractor; S5. According to the analysis result of S4, a trajectory planning unit is used to plan the driving trajectory of the tractor and the front wheels of the aircraft during the wheel alignment process; S6, using the command execution module to perform automatic driving control on the tractor according to the driving trajectory planned in S5; In S1-S2, a three-dimensional laser scanner is used to acquire three-dimensional data of the front wheel of the aircraft, and a distance sensor is used to acquire distance data between the front wheel of the aircraft and the wheel holding mechanism and offset data between the front wheel of the aircraft and the lifting platform. The distance sensors are arranged on both sides along the center point of the lifting platform. A three-dimensional model of the front wheel of the aircraft is established according to the three-dimensional data of the front wheel of the aircraft, the relative position between the front wheel of the aircraft and the lifting platform is determined by using the distance data and the offset data, and the established three-dimensional model of the front wheel of the aircraft is imported into the digital three-dimensional model; In S3, the model mapping unit is used to project the imported digitized three-dimensional model of the front wheel of the aircraft from top to bottom to obtain a digitized two-dimensional model, and a plane rectangular coordinate system is established on the digitized two-dimensional model with the center point of the lifting platform as the origin, and each coordinate point in the plane rectangular coordinate system is assigned a coordinate value; Since the front wheel of the aircraft is composed of at least two tires, the center points A and B of at least two tires are assigned coordinate values and ; Take any point C from the plane rectangular coordinate system, the coordinate value of C is , use the function to build a unit to calculate the distance between center point A and point C and between center point B and point C according to the following formula: ； ； in, represents the distance between the center point A and point C, Represents the distance between the center point B and point C; when When , it indicates that point C is the point on the center axis of the aircraft's front wheel; The function building unit obtains the offset function according to the coordinates of at least two points C on the central axis of the front wheels of the aircraft. , where a represents the slope of the offset function, and b represents the intersection point between the offset function and the Y axis of the plane rectangular coordinate system; when When , it indicates that the front wheel of the aircraft is offset to the left relative to the lifting platform. The offset function at this time is: ; when When , it indicates that the front wheel of the aircraft is offset to the right relative to the lifting platform. The offset function at this time is: .

2. The wheel control method of a towbarless aircraft tractor according to claim 1, characterized in that: In S4-S5, when When the offset analysis unit is used to analyze the offset function, the offset function is respectively set to In and , the coordinate value of the intersection between the offset function and the X-axis of the plane rectangular coordinate system is The coordinate value of the intersection between the offset function and the Y axis of the plane rectangular coordinate system is ,in ; At this time, the offset analysis unit is used to measure the offset angle of the aircraft's front wheels relative to the lifting platform. Perform the calculation: ； Then the offset angle of the aircraft's front wheel relative to the lifting platform is ; The driving trajectory of the tractor planned by the trajectory planning unit is: driving along the positive semi-axis direction of the X-axis of the plane rectangular coordinate system After the distance, it deflects toward the positive half axis of the Y axis of the plane rectangular coordinate system Angle, continue driving until the wheel-holding mechanism on the tractor completes the clamping of the aircraft's front wheels; when When the offset analysis unit is used to analyze the offset function, the offset function is respectively set to In and , the coordinate value of the intersection between the offset function and the X-axis of the plane rectangular coordinate system is The coordinate value of the intersection between the offset function and the Y axis of the plane rectangular coordinate system is ,in ; At this time, the offset analysis unit is used to measure the offset angle of the aircraft's front wheels relative to the lifting platform. Perform the calculation: ； Then the offset angle of the aircraft's front wheel relative to the lifting platform is ; At this point, it is necessary to determine the coordinate point where the tractor is offset on the offset function; The minimum distance value collected by the distance sensor is ,Will Substitute the horizontal coordinate of the coordinate point where the tractor is offset on the offset function into the offset function get , then the coordinate value in the plane rectangular coordinate system is The coordinate point for the tractor to be offset; At this time, the initial offset angle of the tractor is analyzed by the offset analysis unit. Perform the calculation: ； The trajectory of the tractor planned by the trajectory planning unit is: deflection from the original position to the positive semi-axis direction of the Y axis of the plane rectangular coordinate system Angle, then to the coordinate point Directions Distance, and then deflected toward the negative semi-axis direction of the Y axis of the plane rectangular coordinate system Continue driving until the wheel-holding mechanism on the tractor completes the clamping of the aircraft's front wheels.

3. The wheel control method of a towbarless aircraft tractor according to claim 2, characterized in that: In S6, according to the driving trajectory planned by the trajectory planning unit, the turning angle control unit is used to control the offset angle of the tractor during the automatic driving process, and the distance control unit is used to control the driving distance of the tractor during the automatic driving process.

4. A wheel control system for a towbarless tractor for an aircraft that implements the wheel control method for a towbarless tractor for an aircraft according to any one of claims 1 to 3, characterized in that: The system includes a data acquisition module, a data processing module, a data analysis module and an instruction execution module; The data acquisition module is used to acquire various information data before the tractor controls the wheels and during the automatic driving of the tractor, the data processing module is used to process the various information data acquired by the data acquisition module, the data analysis module is used to analyze the information data after data processing to determine the driving trajectory of the tractor and the front wheel of the aircraft during the wheel alignment process, and the instruction execution module is used to execute the control instruction of the tractor according to the driving trajectory obtained by the data analysis unit; The output end of the data acquisition module is connected to the input end of the data processing module and the instruction execution module, the output end of the data processing module is connected to the input end of the data analysis module, and the output end of the data analysis module is connected to the input end of the instruction execution module.

5. The wheel control system of the aircraft towbarless tractor according to claim 4, characterized in that: The data acquisition module includes a three-dimensional laser scanner, a distance sensor and an electromagnetic sensor; The three-dimensional laser scanner is installed at the tail of the tractor to scan and obtain the three-dimensional data of the front wheels of the aircraft; the distance sensor is installed on the wheel-holding mechanism of the tractor to obtain the distance data between the lifting platform and the front wheels of the aircraft, and at the same time, it is also used to obtain the offset data between the front wheels of the aircraft and the lifting platform; the electromagnetic sensor is installed on the steering wheel and tire spindle of the tractor to control the steering wheel rotation angle data and the driving distance data of the tractor during the automatic driving process.

6. The wheel control system of the aircraft towbarless tractor according to claim 5, characterized in that: The data processing module includes a model building unit, a digital three-dimensional model, a model mapping unit and a function building unit; The model building unit is used to build a three-dimensional model of the front wheel of the aircraft according to the three-dimensional data obtained by the three-dimensional laser scanner; the digital three-dimensional model is a three-dimensional model of the entire tractor established in advance; the model mapping unit is used to project the digital three-dimensional model from top to bottom to obtain a digital two-dimensional model, and the model mapping unit also establishes a plane rectangular coordinate system on the digital two-dimensional model with the center point of the lifting platform as the origin, and assigns a coordinate value to each point in the digital two-dimensional model; the function building unit is used to establish an offset function according to at least two coordinate points on the center axis of the front wheel of the aircraft; The output end of the three-dimensional laser scanner is connected to the input end of the model building unit, the output ends of the model building unit and the distance sensor are connected to the input end of the digitized three-dimensional model, and the output end of the function building unit is connected to the input end of the data analysis module.

7. The wheel control system of the aircraft towbarless tractor according to claim 6, characterized in that: The data analysis module includes an offset analysis unit and a trajectory planning unit; The offset analysis unit determines the offset of the front wheel of the aircraft relative to the tractor by calculating the coordinate value of the intersection between the offset function and the plane rectangular coordinate system; the trajectory planning unit is used to plan the driving trajectory of the tractor according to the offset of the front wheel of the aircraft relative to the tractor; The output end of the function establishment unit is connected to the input end of the offset analysis unit, the output end of the offset analysis unit is connected to the input end of the trajectory planning unit, and the output end of the trajectory planning unit is connected to the input end of the instruction execution module.

8. The wheel control system of the aircraft towbarless tractor according to claim 7, characterized in that: The instruction execution module includes a turning angle control unit and a distance control unit; The turning angle control unit is used to control the deviation angle of the tractor according to the driving trajectory planned by the trajectory planning unit during the automatic driving of the tractor; The distance control unit is used to control the driving distance of the tractor according to the driving trajectory planned by the trajectory planning unit during the automatic driving of the tractor; The output ends of the trajectory planning unit and the electromagnetic sensor are connected to the input ends of the turning angle control unit and the distance control unit.

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