Method and system for monitoring external suspension state of helicopter

Abstract

The invention belongs to the technical field of helicopter external hanging state monitoring, and discloses a method and system applied to helicopter external hanging state monitoring, and the method comprises the steps: firstly building a helicopter body coordinate system with the gravity center of a helicopter as an original point, and obtaining real-time helicopter positioning data, helicopter attitude angle data and external hanging object positioning data; then calculating the position of the externally hung object in the body coordinate system according to the data; then calculating the position of a hanging point, and correcting the position of the externally hung object according to the position of the hanging point; calculating the actual gravity center position of the externally hung object, and judging whether the actual gravity center position exceeds the flight envelope of the helicopter; finally, a three-dimensional image of the attitude relation between the externally hung object and the helicopter is displayed in real time, and if the attitude of the externally hung object exceeds the flight envelope, the helicopter gives an alarm and generates a corresponding flight control adjustment instruction to assist a pilot in controlling the helicopter. Through accurate position calculation, a dynamic correction mechanism and an effective flight control adjustment strategy, the external suspension stability, safety and transportation efficiency of the helicopter are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of helicopter external suspension state monitoring. More specifically, the present invention relates to a method and system for monitoring the state of a helicopter external suspension. Background Art

[0002] With the rapid development of aviation technology, helicopters are increasingly widely used in various complex environments. Among them, the transportation of external suspended loads is an important mission task of helicopters, playing a key role in fields such as vertical replenishment, rescue, and material transportation. However, in actual applications, helicopter external suspension transportation still faces many challenges. When the helicopter flies at high speed, the suspended load generates unsteady aerodynamic loads, the aerodynamic characteristics are unstable, the external suspended load swings irregularly, and the two may exhibit coupled oscillations. The pilot cannot accurately perceive the relative position relationship and motion situation between the external suspended load and the helicopter, and improper operation may seriously affect flight safety. There are significant deficiencies in the current monitoring of the state of external suspended loads.

[0003] First of all, the existing systems lack accuracy in the calculation and correction of the position of the external suspended load. Most systems only rely on GPS positioning data and do not fully consider the influence of the sling swing on the actual position of the external suspended load, resulting in a deviation between the calculation result and the actual situation. This inaccurate position calculation method is not conducive to the helicopter maintaining stable flight and also increases the flight safety risk. In addition, in determining the center of gravity position of the external suspended load, the existing technology usually equates the installation position of the GPS receiver with the center of gravity of the external suspended load, ignoring the possible deviation between the two. This simplified processing method causes the system to be unable to accurately grasp the true center of gravity position of the external suspended load, thus affecting the accuracy and effectiveness of subsequent adjustments. Currently, the pilot has no effective means to accurately understand the relative position relationship and motion situation between the helicopter and the external suspension, and cannot accurately know the attitude relationship between the external suspended load and the helicopter, which is prone to misoperation. Finally, these problems comprehensively lead to insufficient stability and safety of the helicopter during the transportation of external suspended loads, restricting the potential of helicopters for efficient application in complex environments. Summary of the Invention

[0004] In order to overcome the problems of insufficient stability and safety of the helicopter during the transportation of external suspended loads in the prior art, the present invention proposes a method and system for monitoring the state of a helicopter external suspension to solve the above problems.

[0005] The present invention provides the following technical solutions:

[0006] A method for monitoring the state of a helicopter external suspension, comprising:

[0007] Establish a three-dimensional coordinate system with the center of gravity of the helicopter as the origin, and define it as the body coordinate system; obtain real-time helicopter positioning data, helicopter attitude angle data, and external suspension positioning data;

[0008] According to the real-time helicopter positioning data, helicopter attitude angle data, and external suspension positioning data, calculate the position of the external suspension in the body coordinate system, and record it as the external suspension position;

[0009] Obtain real-time sling swing data, and calculate the position of the suspension point in the body coordinate system according to the sling swing data and the sling length, and record it as the suspension point position;

[0010] Correct the external suspension position according to the suspension point position to obtain the corrected external suspension position;

[0011] Obtain the pre-measured center of gravity offset data, and obtain the center of gravity position of the external suspension according to the corrected external suspension position and the center of gravity offset data;

[0012] According to the position and attitude relationship between the external suspension and the helicopter, establish a three-dimensional image of the attitude relationship between the external suspension and the helicopter, and display it in real time on the helicopter integrated display system; if the attitude of the external suspension exceeds the flight envelope, the helicopter will give an alarm. When the relative position relationship between the external suspension and the helicopter is within the ideal center of gravity range, the three-dimensional image on the screen of the integrated display system is green; when it is at the boundary of the ideal center of gravity range, the three-dimensional image on the screen of the integrated display system is yellow; when it exceeds the ideal center of gravity range, the three-dimensional image on the screen of the integrated display system is red, and the helicopter will give a voice alarm;

[0013] Generate corresponding flight control adjustment instructions according to the center of gravity position of the external suspension and the pre-defined ideal center of gravity range.

[0014] Preferably, the body coordinate system takes the center of gravity of the helicopter as the origin, the X-axis points to the nose direction, the Y-axis points to the right side direction of the helicopter body, and the Z-axis points to the ground direction; the helicopter positioning data is the GPS coordinates of the helicopter, which are obtained through the GPS system installed on the helicopter; the helicopter attitude angle data includes pitch angle, roll angle, and yaw angle, which are measured through the inertial measurement system installed on the helicopter; the external suspension positioning data is the GPS coordinates of the external suspension, which are obtained through the GPS system installed on the external suspension.

[0015] Preferably, the steps of calculating the position of the external suspension in the body coordinate system include:

[0016] Convert the GPS coordinates of the helicopter and the GPS coordinates of the external suspension into coordinates in the Earth-centered Earth-fixed coordinate system;

[0017] Obtain the coordinates (X1, Y1, Z1) based on the transformed coordinates; where X1 is obtained by subtracting the X-axis coordinate of the helicopter from the X-axis coordinate of the external suspended object, Y1 is obtained by subtracting the Y-axis coordinate of the helicopter from the Y-axis coordinate of the external suspended object, and Z1 is obtained by subtracting the Z-axis coordinate of the helicopter from the Z-axis coordinate of the external suspended object;

[0018] Calculate the transformation matrix R based on the helicopter attitude angle data;

[0019] Multiply (X1, Y1, Z1) on the left by the transformation matrix R to obtain (X2, Y2, Z2), and use (X2, Y2, Z2) to represent the position of the external suspended object in the body coordinate system, where X2 represents the X-axis coordinate in the body coordinate system, Y2 represents the Y-axis coordinate in the body coordinate system, and Z2 represents the Z-axis coordinate in the body coordinate system.

[0020] Preferably, the step of calculating the transformation matrix R based on the helicopter attitude angle data includes:

[0021] Construct the first basic matrix Rx through the following formula:

[0022] where φ represents the pitch angle;

[0023] Construct the second basic matrix Ry through the following formula:

[0024] where θ represents the roll angle;

[0025] Construct the third basic matrix Rz through the following formula:

[0026] where ψ represents the yaw angle;

[0027] Perform matrix multiplication operations on the first basic matrix Rx, the second basic matrix Ry, and the third basic matrix Rz in sequence to obtain the transformation matrix R.

[0028] Preferably, the sling swing data includes the sling swing angle and the swing direction angle, and is obtained by an angle sensor and a direction sensor installed on the sling;

[0029] The step of calculating the position of the suspension point in the body coordinate system includes:

[0030] Decompose the swing angle into the X-axis direction component and the Y-axis direction component through the following formula;

[0031]

[0032] where βx represents the X-axis direction component, βy represents the Y-axis direction component, β represents the swing angle, and α represents the swing direction angle;

[0033] According to the swing angle, X-axis direction component, and Y-axis direction component of the sling length, the coordinates (X3, Y3, Z3) are obtained, where X3 = L×sin(βx), Y3 = L×sin(βy), Z3 = -L×(1 - cos(β)), and L represents the sling length;

[0034] Multiply (X3, Y3, Z3) by the transformation matrix R on the left to obtain (X4, Y4, Z4), and use (X4, Y4, Z4) to represent the position of the suspension point in the body coordinate system, where X4 represents the X-axis coordinate in the body coordinate system, Y4 represents the Y-axis coordinate in the body coordinate system, and Z4 represents the Z-axis coordinate in the body coordinate system.

[0035] Preferably, the step of correcting the position of the externally suspended object according to the position of the suspension point to obtain the corrected position of the externally suspended object includes:

[0036] Use the following formula to calculate the coordinates (X5, Y5, Z5) of the corrected position of the externally suspended object in the body coordinate system:

[0037] Use (X5, Y5, Z5) to represent the corrected position of the externally suspended object, and q represents a preset adjustment coefficient.

[0038] Preferably, the center-of-gravity offset data is (ΔX, ΔY, ΔZ), where ΔX is the distance on the X-axis in the Earth-centered Earth-fixed coordinate system between the position of the GPS system installed on the externally suspended object and the center of gravity of the externally suspended object, ΔY is the distance on the Y-axis in the Earth-centered Earth-fixed coordinate system between the position of the GPS system installed on the externally suspended object and the center of gravity of the externally suspended object, and ΔZ is the distance on the Y-axis in the Earth-centered Earth-fixed coordinate system between the position of the GPS system installed on the externally suspended object and the center of gravity of the externally suspended object;

[0039] The step of obtaining the center-of-gravity position of the externally suspended object according to the corrected position of the externally suspended object and the center-of-gravity offset data includes:

[0040] Use the following formula to calculate the coordinates (X6, Y6, Z6) of the center-of-gravity position of the externally suspended object in the body coordinate system;

[0041] Use (X6, Y6, Z6) to represent the center-of-gravity position of the externally suspended object.

[0042] Preferably, the step of generating a corresponding adjustment command according to the center-of-gravity position of the externally suspended object and a predefined ideal center-of-gravity range includes:

[0043] Obtain a position deviation vector according to the latest center-of-gravity position of the externally suspended object and the ideal center-of-gravity position, and the position deviation vector includes an X-axis deviation, a Y-axis deviation, and a Z-axis deviation;

[0044] Obtain the external suspension movement trend index vector based on the center-of-gravity position of the external suspension in at least one recent movement cycle. The movement trend index vector includes the X-axis movement trend index, the Y-axis movement trend index, and the Z-axis movement trend index;

[0045] Generate a corresponding pitch angle adjustment command according to the X-axis deviation and the X-axis movement trend index;

[0046] Generate a corresponding roll angle adjustment command according to the Y-axis deviation and the Y-axis movement trend index;

[0047] Generate a corresponding collective pitch adjustment command according to the Z-axis deviation and the Z-axis movement trend index;

[0048] The pitch angle adjustment command, the roll angle adjustment command, and the collective pitch adjustment command form the flight control adjustment command.

[0049] The present invention also provides a system for monitoring the state of an external suspension of a helicopter, which is used to implement a method for monitoring the state of an external suspension of a helicopter, including:

[0050] A coordinate system establishment and data acquisition module, which is used to establish a three-dimensional coordinate system with the center of gravity of the helicopter as the origin and define it as the body coordinate system; obtain real-time helicopter positioning data, helicopter attitude angle data, and external suspension positioning data;

[0051] An external suspension position calculation module, which is used to calculate the position of the external suspension in the body coordinate system according to the real-time helicopter positioning data, attitude data, and external suspension positioning data, and record it as the external suspension position;

[0052] A suspension point position calculation module, which is used to obtain real-time sling swing data, and calculate the position of the suspension point in the body coordinate system according to the sling swing data and the sling length, and record it as the suspension point position;

[0053] An external suspension position correction module, which is used to correct the external suspension position according to the suspension point position to obtain the corrected external suspension position;

[0054] A center-of-gravity position calculation module, which is used to obtain pre-measured center-of-gravity offset data, and obtain the center-of-gravity position of the external suspension according to the corrected external suspension position and the center-of-gravity offset data;

[0055] A state monitoring and warning module, which is used to establish a three-dimensional image of the attitude relationship between the external suspension and the helicopter in the integrated display system according to the center-of-gravity position of the external suspension and the predefined ideal center-of-gravity range, monitor the state of the external suspension in real time and give warnings in a timely manner;

[0056] A flight control module, which is used to generate corresponding flight control adjustment commands according to the center-of-gravity position of the external suspension and the predefined ideal center-of-gravity range.

[0057] The present invention provides a method and system for monitoring the external suspension state of a helicopter, which has the following beneficial effects:

[0058] By establishing a three-dimensional coordinate system with the helicopter as the origin and comprehensively using the helicopter positioning data, helicopter attitude angle data, and external suspension object positioning data, the precise calculation of the position of the external suspension object is realized, overcoming the limitations of traditional single GPS positioning. By introducing the sling swing data and sling length to correct the position of the external suspension object, the influence of the sling dynamics on the actual position of the external suspension object is effectively considered, making the position calculation closer to the actual situation. At the same time, by introducing the pre-measured center of gravity offset data, the precise conversion from the GPS receiver position to the actual center of gravity position of the external suspension object is realized, overcoming the simplified processing method of equating the GPS receiver position with the center of gravity of the external suspension object. By calculating the position deviation vector and trend index vector, the current deviation and change trend of the center of gravity position of the external suspension object are comprehensively considered, overcoming the limitations of traditional static position judgment only, and being able to generate flight control adjustment instructions more intelligently. By establishing a three-dimensional image of the attitude relationship between the external suspension object and the helicopter and displaying it in real time on the comprehensive display system, the problem that the pilot cannot accurately perceive the attitude of the external suspension object is solved; by generating adjustment instructions for the pitch angle, roll angle, and collective pitch, the omnidirectional adjustment of the helicopter attitude is realized, overcoming the limitations of single-direction adjustment and being able to respond more comprehensively to complex center of gravity changes. Generally speaking, the method proposed by the present invention improves the stability, safety, and transportation efficiency of the external suspension of the helicopter through precise position calculation, dynamic correction mechanism, and effective adjustment strategy. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] Figure 1 is a schematic flow chart of a method for monitoring the external suspension state of a helicopter according to the present invention;

[0060] Figure 2 is a schematic module diagram of a system for monitoring the external suspension state of a helicopter according to the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0061] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0062] Embodiment 1

[0063] Please refer to Figure 1 , in this embodiment, a method for monitoring the external suspension state of a helicopter includes:

[0064] S1. Establish a three-dimensional coordinate system with the helicopter's center of gravity as the origin and define it as the body coordinate system; obtain real-time helicopter positioning data, helicopter attitude angle data, and external suspension object positioning data.

[0065] The body coordinate system has the helicopter's center of gravity as the origin, the X-axis points in the nose direction, the Y-axis points in the right direction of the helicopter, and the Z-axis points in the ground direction; the helicopter positioning data is the GPS coordinates of the helicopter, obtained through the GPS system installed on the helicopter; the helicopter attitude angle data includes pitch angle, roll angle, and yaw angle, measured through the inertial measurement system installed on the helicopter; the external suspension object positioning data is the GPS coordinates of the external suspension object, obtained through the GPS system installed on the external suspension object.

[0066] In this embodiment, establishing a three-dimensional coordinate system with the helicopter's center of gravity as the origin and obtaining relevant data can be carried out according to the following steps: First, install a set of high-precision inertial measurement systems (IMU) on the helicopter. This system usually includes accelerometers, gyroscopes, and magnetometers. Next, use the position where the helicopter's center of gravity is located as the origin of the body coordinate system. Define the three axes of the helicopter body coordinate system. The X-axis points in the nose direction, the Y-axis points in the right direction of the helicopter body, and the Z-axis points in the ground direction. In this way, a three-dimensional coordinate system with the helicopter's center of gravity as the origin is established.

[0067] Then, install a high-precision GPS receiver on the helicopter to obtain real-time positioning data of the helicopter. To improve the positioning accuracy, differential GPS (DGPS) or real-time kinematic (RTK) GPS technology can be used, which can improve the positioning accuracy to the centimeter level.

[0068] For the acquisition of helicopter attitude angle data, use the installed IMU system. The IMU can calculate the pitch angle, roll angle, and yaw angle of the helicopter in real time by fusing the data of accelerometers, gyroscopes, and magnetometers. These angle data are usually output in the form of Euler angles.

[0069] Finally, install an independent GPS receiver on the external suspended load to obtain the real-time positioning data of the external suspended load. This GPS receiver is usually installed on the top of the external suspended load or other positions where satellite signals can be easily received. Similarly, DGPS or RTK technology can be used to improve the positioning accuracy. At the same time, to synchronize and process these data, a central processing unit (CPU) can be set on the helicopter. This CPU receives the data of the helicopter GPS and IMU through a wired connection and receives the data of the external suspended load GPS through wireless communication. The CPU collects the data of all sensors at a fixed frequency (e.g., 10Hz) to ensure the time consistency of the data. Through the above steps, the establishment of the body coordinate system is completed, and the real-time helicopter positioning data, helicopter attitude angle data, and external suspended load positioning data are obtained. These data provide a basis for subsequent coordinate transformation and position calculation.

[0070] S2. Calculate the position of the external suspended load in the body coordinate system based on the real-time helicopter positioning data, helicopter attitude angle data, and external suspended load positioning data, and record it as the external suspended load position;

[0071] The steps of calculating the position of the external suspended load in the body coordinate system include:

[0072] Convert the GPS coordinates of the helicopter and the GPS coordinates of the external suspended load into coordinates in the Earth-centered Earth-fixed coordinate system;

[0073] Obtain the coordinates (X1, Y1, Z1) based on the converted coordinates; where X1 is obtained by subtracting the X-axis coordinate of the helicopter from the X-axis coordinate of the external suspended load, Y1 is obtained by subtracting the Y-axis coordinate of the helicopter from the Y-axis coordinate of the external suspended load, and Z1 is obtained by subtracting the Z-axis coordinate of the helicopter from the Z-axis coordinate of the external suspended load;

[0074] Calculate the transformation matrix R based on the helicopter attitude angle data;

[0075] Multiply (X1, Y1, Z1) on the left by the transformation matrix R to obtain (X2, Y2, Z2), and use (X2, Y2, Z2) to represent the position of the external suspended load in the body coordinate system, where X2 represents the X-axis coordinate in the body coordinate system, Y2 represents the Y-axis coordinate in the body coordinate system, and Z2 represents the Z-axis coordinate in the body coordinate system.

[0076] The steps of calculating the transformation matrix R based on the helicopter attitude angle data include:

[0077] Construct the first fundamental matrix Rx through the following formula:

[0078] where φ represents the pitch angle;

[0079] Construct the second fundamental matrix Ry through the following formula:

[0080] Among them, θ represents the roll angle;

[0081] The third basic matrix Rz is constructed through the following formula:

[0082] Among them, ψ represents the yaw angle;

[0083] The first basic matrix Rx, the second basic matrix Ry, and the third basic matrix Rz are successively subjected to matrix multiplication operations to obtain the transformation matrix R.

[0084] In this embodiment, calculating the position of the external suspended load in the body coordinate system can be performed according to the following steps:

[0085] First, using the WGS84 coordinate conversion algorithm, the GPS coordinates of the helicopter and the external suspended load are converted into coordinates in the Earth-Centered Earth-Fixed (ECEF) coordinate system. Then, by calculating the difference between the ECEF coordinates of the external suspended load and the ECEF coordinates of the helicopter, the position vector of the external suspended load relative to the helicopter is obtained. Then, according to the helicopter attitude angle data (including pitch angle, roll angle, and yaw angle) of the helicopter, three basic rotation matrices are constructed. In the usual order, first yaw, then pitch, and finally roll; these three matrices are successively multiplied to obtain the final transformation matrix. This step can be assisted by a dedicated matrix operation library to improve the calculation efficiency and accuracy.

[0086] Finally, the obtained transformation matrix and the relative position vector are subjected to matrix multiplication operations. Similarly, this step can also use a dedicated operation library to improve the efficiency and accuracy of mathematical calculations. The result of the operation is the position coordinates of the external suspended load in the body coordinate system.

[0087] S3. Obtain real-time sling swing data, and calculate the position of the suspension point in the body coordinate system according to the sling swing data and the sling length, and record it as the suspension point position;

[0088] The sling swing data includes the sling swing angle and the swing direction angle, and is obtained through angle sensors and direction sensors installed on the sling;

[0089] The steps for calculating the position of the suspension point in the body coordinate system include:

[0090] The swing angle is decomposed into the X-axis direction component and the Y-axis direction component through the following formula;

[0091]

[0092] Among them, βx represents the X-axis direction component, βy represents the Y-axis direction component, β represents the swing angle, and α represents the swing direction angle;

[0093] According to the swinging angle of the sling, the X-axis direction component, and the Y-axis direction component, the coordinates (X3, Y3, Z3) are obtained, where X3 = L×sin(βx), Y3 = L×sin(βy), Z3 = -L×(1 - cos(β)), and L represents the sling length;

[0094] Multiply (X3, Y3, Z3) by the transformation matrix R on the left to obtain (X4, Y4, Z4), and use (X4, Y4, Z4) to represent the position of the suspension point in the body coordinate system, where X4 represents the X-axis coordinate in the body coordinate system, Y4 represents the Y-axis coordinate in the body coordinate system, and Z4 represents the Z-axis coordinate in the body coordinate system.

[0095] In this embodiment, calculating the position of the suspension point in the body coordinate system can be carried out according to the following steps:

[0096] First, the swinging data of the sling are obtained in real time through the angle sensor and the direction sensor installed on the sling. These data include the swinging angle of the sling and the swinging direction angle. The angle sensor can use a high-precision inclinometer, and the direction sensor can use an electronic compass. Then, using the obtained swinging angle and swinging direction angle, the swinging angle is decomposed into components in the X-axis and Y-axis directions. This step is realized by using trigonometric functions. This decomposition method can transform the swinging in three-dimensional space into two components on a plane, which is convenient for subsequent calculations. Then, according to the sling length, the swinging angle, and the X-axis and Y-axis direction components just calculated, the position of the suspension point relative to the helicopter is calculated.

[0097] Finally, multiply the relative position coordinates obtained in the previous step by the transformation matrix on the left to obtain the position of the suspension point in the body coordinate system. The transformation matrix used here is the same as the one used when calculating the position of the external suspended object before.

[0098] S4. Correct the position of the external suspended object according to the position of the suspension point to obtain the corrected position of the external suspended object;

[0099] The correcting the position of the external suspended object according to the position of the suspension point to obtain the corrected position of the external suspended object includes:

[0100] Use the following formula to calculate the coordinates (X5, Y5, Z5) of the corrected position of the external suspended object in the body coordinate system:

[0101] Use (X5, Y5, Z5) to represent the corrected position of the external suspended object, and q represents a preset adjustment coefficient.

[0102] In this embodiment, the process of correcting the position of the external suspended object according to the position of the suspension point can be carried out according to the following steps:

[0103] First, obtain the coordinates of the external suspended load position and the suspension point position in the body coordinate system calculated previously. Both of these positions are three-dimensional coordinates, each containing three components: X, Y, and Z. Then, use a correction formula to calculate the corrected external suspended load position. Taking the X-axis as an example, the corrected X coordinate of the external suspended load is equal to the original X coordinate of the external suspended load plus (the difference between the X coordinate of the suspension point and the X coordinate of the external suspended load) divided by a preset value q. In this example, q is set to 2. The correction methods for the Y-axis and Z-axis are the same as that of the X-axis. The corrected external suspended load position calculated by this method takes into account the influence of the sling on the external suspended load position and simulates the actual effect of the external suspended load being pulled towards the suspension point. At the same time, it has strong real-time performance. After obtaining new position data each time, the correction calculation can be carried out immediately without a complex iterative process, thus being able to quickly respond to the position changes caused by the sling swing. In addition, by adjusting the q value, this method also has high flexibility and can control the degree of correction to adapt to different suspension situations and the characteristics of the external suspended load. The smaller the q value, the greater the correction, and the closer the external suspended load position is to the suspension point; conversely, it is closer to the original calculated position. Correcting the external suspended load position can more accurately reflect the actual position of the external suspended load. Through this correction, a more accurate and real-time estimation of the external suspended load position can be obtained.

[0104] S5. Obtain the pre-measured center of gravity offset data, and obtain the center of gravity position of the external suspended load according to the corrected external suspended load position and the center of gravity offset data;

[0105] The center of gravity offset data is (ΔX, ΔY, ΔZ), where ΔX is the distance along the X-axis in the Earth-Centered Earth-Fixed coordinate system between the position of the GPS system installed on the external suspended load and the center of gravity of the external suspended load, ΔY is the distance along the Y-axis in the Earth-Centered Earth-Fixed coordinate system between the position of the GPS system installed on the external suspended load and the center of gravity of the external suspended load, and ΔZ is the distance along the Z-axis in the Earth-Centered Earth-Fixed coordinate system between the position of the GPS system installed on the external suspended load and the center of gravity of the external suspended load;

[0106] The obtaining of the center of gravity position of the external suspended load according to the corrected external suspended load position and the center of gravity offset data includes:

[0107] Use the following formula to calculate the coordinates (X6, Y6, Z6) of the center of gravity position of the external suspended load in the body coordinate system;

[0108] Use (X6, Y6, Z6) to represent the center of gravity position of the external suspended load.

[0109] In this embodiment, the process of obtaining the pre-measured center of gravity offset data and calculating the center of gravity position of the external suspended load is as follows:

[0110] First, obtain the pre-measured center of gravity offset data. These data reflect the distance difference between the position of the GPS system installed on the external suspended load and the actual center of gravity of the external suspended load. Specifically, it includes the distance differences in the three directions of the X-axis, Y-axis, and Z-axis in the Earth-Centered Earth-Fixed coordinate system. These data are usually obtained through precise measurement before the external suspended load is loaded and stored in the form of (ΔX, ΔY, ΔZ).

[0111] Next, use the corrected position of the external suspended load and the center of gravity offset data to calculate the actual center of gravity position of the external suspended load. Since it is usually difficult to install the positioning device (such as a GPS receiver) at the exact center of gravity position of the external suspended load. Therefore, the previously calculated position is actually the position of the positioning device, rather than the true center of gravity position of the external suspended load. By adding this pre-measured deviation, the actual position of the center of gravity of the external suspended load can be estimated more accurately, and accurate data reference can be provided for subsequent center of gravity adjustment.

[0112] S6. Generate corresponding flight control adjustment instructions according to the center of gravity position of the external suspended load and the predefined ideal center of gravity range.

[0113] The step of generating corresponding flight control adjustment instructions according to the center of gravity position of the external suspended load and the predefined ideal center of gravity range includes:

[0114] Obtain a position deviation vector based on the latest center of gravity position of the external suspended load and the ideal center of gravity position. The position deviation vector includes X-axis deviation, Y-axis deviation, and Z-axis deviation;

[0115] Obtain an external suspended load movement trend index vector based on the center of gravity position of the external suspended load in at least the most recent 1 movement cycle. The external suspended load movement trend index vector includes an X-axis movement trend index, a Y-axis movement trend index, and a Z-axis movement trend index;

[0116] Generate a corresponding pitch angle adjustment instruction according to the X-axis deviation and the X-axis movement trend index;

[0117] Generate a corresponding roll angle adjustment instruction according to the Y-axis deviation and the Y-axis movement trend index;

[0118] Generate a corresponding collective pitch adjustment instruction according to the Z-axis deviation and the Z-axis movement trend index;

[0119] The pitch angle adjustment instruction, roll angle adjustment instruction, and collective pitch adjustment instruction form the flight control adjustment instruction.

[0120] In this embodiment, the process of generating adjustment instructions according to the center of gravity position of the external suspended load and the predefined ideal center of gravity range is as follows:

[0121] First, pre-define an ideal center of gravity position, which can be pre-calculated and is a position that enables the helicopter to maintain stability in various flight states. Then, continuously collect the center of gravity position data of the external suspended load at multiple time points (at least one motion cycle).

[0122] Then, calculate the position deviation vector and the trend index vector. The position deviation vector is the difference between the latest sampling point and the ideal position, including the deviations in the X-axis, Y-axis, and Z-axis directions. The motion trend index vector is obtained through linear regression analysis of multiple consecutive sampling points and reflects the change trends of the center of gravity position of the external suspended load in the three directions. Next, determine whether adjustment is needed based on the position deviation and the motion trend index, and generate corresponding adjustment instructions. Specifically:

[0123] For the X-axis direction, if the absolute value of the trend index exceeds the preset threshold and the absolute value of the position deviation also exceeds the allowable error, a pitch angle adjustment instruction needs to be generated. When the motion trend index and the position deviation have the same sign, it means that the position of the external suspended load is moving away from the ideal position, and the pitch angle needs to be increased; otherwise, the pitch angle needs to be decreased.

[0124] For the Y-axis direction, a roll angle adjustment instruction is generated in a similar way. When the Y-axis motion trend index and the position deviation have the same sign and both exceed their respective thresholds, the roll angle needs to be increased; otherwise, the roll angle needs to be decreased.

[0125] For the Z-axis direction, a collective pitch adjustment instruction is generated. Similarly, when the Z-axis motion trend index and the position deviation have the same sign and both exceed the threshold, the collective pitch needs to be increased; otherwise, the collective pitch needs to be decreased.

[0126] Finally, combine the generated pitch angle adjustment instruction, roll angle adjustment instruction, and collective pitch adjustment instruction into the final flight control adjustment instruction. This method not only considers the deviation between the current position and the ideal position but also the trend of position change, and can perform more intelligent adjustments. By setting various preset thresholds, it is possible to avoid frequent adjustments due to minor fluctuations while being able to respond promptly to significant position changes. This method can help the helicopter maintain stability in complex flight environments and improve flight stability and safety.

[0127] Embodiment 2

[0128] Please refer to Figure 2 , the present invention provides a system for monitoring the state of an external suspension of a helicopter, which is used to implement a method for monitoring the state of an external suspension of a helicopter, including:

[0129] A coordinate system establishment and data acquisition module, which is used to establish a three-dimensional coordinate system with the center of gravity of the helicopter as the origin and define it as the body coordinate system; obtain real-time helicopter positioning data, helicopter attitude angle data, and external suspended load positioning data;

[0130] An external suspended load position calculation module, configured to calculate the position of the external suspended load in the body coordinate system according to real-time helicopter positioning data, helicopter attitude angle data, and external suspended load positioning data, and record it as the external suspended load position;

[0131] A suspension point position calculation module, configured to obtain real-time sling swing data, and calculate the position of the suspension point in the body coordinate system according to the sling swing data and the sling length, and record it as the suspension point position;

[0132] An external suspended load position correction module, configured to correct the external suspended load position according to the suspension point position to obtain a corrected external suspended load position;

[0133] A center of gravity position calculation module, configured to obtain pre-measured center of gravity offset data, and obtain the center of gravity position of the external suspended load according to the corrected external suspended load position and the center of gravity offset data;

[0134] A status monitoring and warning module, configured to establish a three-dimensional image of the attitude relationship between the external suspended load and the helicopter in the integrated display system according to the center of gravity position of the external suspended load and a predefined ideal center of gravity range, monitor the status of the external suspended load in real time and give warnings in a timely manner;

[0135] A flight control module, configured to generate corresponding flight control adjustment instructions according to the center of gravity position of the external suspended load and a predefined ideal center of gravity range.

[0136] The present invention significantly improves the stability, safety, and transportation efficiency of the external suspension of the helicopter through precise position calculation, dynamic correction mechanisms, and effective flight control adjustment strategies.

[0137] In several embodiments provided by the present invention, it should be understood that the disclosed systems, devices, and methods can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of the units is only one type, and there may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the displayed or discussed coupling or direct coupling or communication connection between each other can be through some interfaces. The indirect coupling or communication connection of the device or unit can be in electrical, mechanical, or other forms.

[0138] The above is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention can easily think of changes or substitutions, which should all be covered within the protection scope of the present invention.

[0139] Finally, the above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for monitoring the external suspension state of a helicopter, characterized in that, Including: Establish a three-dimensional coordinate system with the center of gravity of the helicopter as the origin and define it as the body coordinate system; obtain real-time helicopter positioning data, helicopter attitude angle data, and external suspension positioning data. According to the real-time helicopter positioning data, helicopter attitude angle data, and external suspension positioning data, calculate the position of the external suspension in the body coordinate system and record it as the external suspension position. Obtain real-time sling swing data, and calculate the position of the suspension point in the body coordinate system according to the sling swing data and the sling length, and record it as the suspension point position. Correct the external suspension position according to the suspension point position to obtain the corrected external suspension position. Obtain the pre-measured center of gravity offset data, and obtain the center of gravity position of the external suspension according to the corrected external suspension position and the center of gravity offset data. Judge whether the attitude of the external suspension exceeds the flight envelope according to the actual center of gravity position of the external suspension and the predefined ideal center of gravity range. If the attitude of the external suspension exceeds the flight envelope, the helicopter gives an alarm, and generates a corresponding flight control adjustment instruction according to the actual center of gravity position of the external suspension and the predefined ideal center of gravity range to assist the pilot in controlling the helicopter.

2. The method for monitoring the external suspension state of a helicopter according to claim 1, characterized in that, The body coordinate system has the center of gravity of the helicopter as the origin, the X-axis points in the nose direction, the Y-axis points in the right side direction of the helicopter body, and the Z-axis points in the ground direction; the helicopter positioning data is the GPS coordinates of the helicopter, which are obtained through the GPS system installed on the helicopter; the helicopter attitude angle data includes pitch angle, roll angle, and yaw angle, which are measured through the inertial measurement system installed on the helicopter; the external suspension positioning data is the GPS coordinates of the external suspension, which are obtained through the GPS system installed on the external suspension.

3. A method for monitoring the external suspension state of a helicopter according to claim 2, characterized in that, The steps of calculating the position of the external suspension in the body coordinate system include: Convert the GPS coordinates of the helicopter and the GPS coordinates of the external suspension into coordinates in the Earth-Centered Earth-Fixed coordinate system. Obtain the coordinates (X1, Y1, Z1) according to the converted coordinates; where, X1 is obtained by subtracting the X-axis coordinate of the helicopter from the X-axis coordinate of the external suspension, Y1 is obtained by subtracting the Y-axis coordinate of the helicopter from the Y-axis coordinate of the external suspension, and Z1 is obtained by subtracting the Z-axis coordinate of the helicopter from the Z-axis coordinate of the external suspension. Calculate the transformation matrix R according to the helicopter attitude angle data. Multiply (X1, Y1, Z1) on the left by the transformation matrix R to get (X2, Y2, Z2), and use (X2, Y2, Z2) to represent the position of the external suspension in the body coordinate system, where X2 represents the X-axis coordinate in the body coordinate system, Y2 represents the Y-axis coordinate in the body coordinate system, and Z2 represents the Z-axis coordinate in the body coordinate system.

4. A method for monitoring the external suspension state of a helicopter according to claim 3, characterized in that, The steps of calculating the transformation matrix R according to the helicopter attitude angle data include: Construct the first fundamental matrix Rx through the following formula: Wherein, φ represents the pitch angle; Construct the second fundamental matrix Ry through the following formula: Wherein, θ represents the roll angle; Construct the third fundamental matrix Rz through the following formula: Where ψ represents the yaw angle; Perform matrix multiplication operations on the first fundamental matrix Rx, the second fundamental matrix Ry, and the third fundamental matrix Rz in sequence to obtain the transformation matrix R.

5. A method for monitoring the external suspension state of a helicopter according to claim 4, characterized in that, The sling swing data includes the sling swing angle and the swing direction angle, which are obtained through the angle sensor and the direction sensor installed on the sling. The steps of calculating the position of the suspension point in the body coordinate system include: Decompose the swing angle into the X-axis direction component and the Y-axis direction component through the following formula; Among them, βx represents the X-axis direction component, βy represents the Y-axis direction component, β represents the swing angle, and α represents the swing direction angle; According to the sling length, swing angle, X-axis direction component and Y-axis direction component, obtain the coordinates (X3, Y3, Z3), where X3 = L×sin(βx), Y3 = L×sin(βy), Z3 = -L×(1 - cos(β)), and L represents the sling length; Multiply (X3, Y3, Z3) by the transformation matrix R on the left to obtain (X4, Y4, Z4), and use (X4, Y4, Z4) to represent the position of the suspension point in the body coordinate system, where X4 represents the X-axis coordinate in the body coordinate system, Y4 represents the Y-axis coordinate in the body coordinate system, and Z4 represents the Z-axis coordinate in the body coordinate system.

6. A method for monitoring the external suspension state of a helicopter, as claimed in claim 5, wherein The step of correcting the position of the externally suspended object according to the position of the suspension point to obtain the corrected position of the externally suspended object includes: Calculate the coordinates (X5, Y5, Z5) of the corrected position of the externally suspended object in the body coordinate system using the following formula: Use (X5, Y5, Z5) to represent the corrected position of the external suspended load, and q represents the preset adjustment coefficient.

7. A method for monitoring the external hanging state of a helicopter according to claim 6, characterized in that, The center-of-gravity offset data is (ΔX, ΔY, ΔZ), where ΔX is the distance on the X-axis in the Earth-Centered Earth-Fixed coordinate system between the position of the GPS system installed on the externally suspended object and the center of gravity of the externally suspended object, ΔY is the distance on the Y-axis in the Earth-Centered Earth-Fixed coordinate system between the position of the GPS system installed on the externally suspended object and the center of gravity of the externally suspended object, and ΔZ is the distance on the Y-axis in the Earth-Centered Earth-Fixed coordinate system between the position of the GPS system installed on the externally suspended object and the center of gravity of the externally suspended object; The step of obtaining the center-of-gravity position of the externally suspended object according to the corrected position of the externally suspended object and the center-of-gravity offset data includes: Calculate the coordinates (X6, Y6, Z6) of the center-of-gravity position of the externally suspended object in the body coordinate system using the following formula; Use (X6, Y6, Z6) to represent the center of gravity position of the external suspended load.

8. A method for monitoring the external suspension state of a helicopter according to claim 7, characterized in that, According to the position and attitude relationship between the externally suspended object and the helicopter, establish a three-dimensional image of the attitude relationship between the externally suspended object and the helicopter in the helicopter integrated display system; if the attitude of the externally suspended object exceeds the flight envelope, the helicopter gives an alarm; when the relative position relationship between the externally suspended object and the helicopter is within the ideal center-of-gravity range, the three-dimensional image on the screen of the integrated display system is green; when it is at the boundary of the ideal center-of-gravity range, the three-dimensional image on the screen of the integrated display system is yellow; when it exceeds the ideal center-of-gravity range, the three-dimensional image on the screen of the integrated display system is red, and the helicopter gives a voice alarm.

9. A method for monitoring the external suspension state of a helicopter according to claim 7, characterized in that The steps of generating corresponding flight control adjustment instructions according to the center-of-gravity position of the externally suspended object and the predefined ideal center-of-gravity range include: Obtain the position deviation vector according to the latest center-of-gravity position of the externally suspended object and the ideal center-of-gravity position, and the position deviation vector includes the X-axis deviation, Y-axis deviation and Z-axis deviation; Obtain the movement trend index vector of the externally suspended object according to the center-of-gravity position of the externally suspended object in at least 1 recent movement cycle, and the trend index vector includes the X-axis movement trend index, Y-axis movement trend index and Z-axis movement trend index; Generate a corresponding pitch angle adjustment instruction according to the X-axis deviation and the X-axis movement trend index; Generate a corresponding roll angle adjustment instruction according to the Y-axis deviation and the Y-axis movement trend index; Generate a corresponding collective pitch adjustment command according to the Z-axis deviation and the Z-axis movement trend index; The pitch angle adjustment command, the roll angle adjustment command and the collective pitch adjustment command form the flight control adjustment command.

10. A system for monitoring the external suspension state of a helicopter, which is used to implement the method for monitoring the external suspension state of a helicopter according to any one of claims 1-8, characterized in that, Including: A coordinate system establishment and data acquisition module, which is used to establish a three-dimensional coordinate system with the center of gravity of the helicopter as the origin and define it as the airframe coordinate system; obtain real-time helicopter positioning data, helicopter attitude angle data and external suspension positioning data; An external suspension position calculation module, which is used to calculate the position of the external suspension in the airframe coordinate system according to the real-time helicopter positioning data, helicopter attitude angle data and external suspension positioning data, and record it as the external suspension position; A suspension point position calculation module, which is used to obtain real-time sling swing data and calculate the position of the suspension point in the airframe coordinate system according to the sling swing data and the sling length, and record it as the suspension point position; An external suspension position correction module, which is used to correct the external suspension position according to the suspension point position to obtain the corrected external suspension position; A center of gravity position calculation module, which is used to obtain pre-measured center of gravity offset data and obtain the external suspension center of gravity position according to the corrected external suspension position and the center of gravity offset data; A status monitoring and warning module, which is used to establish a three-dimensional image of the attitude relationship between the external suspension and the helicopter in the helicopter integrated display system according to the external suspension center of gravity position and the predefined ideal center of gravity range, monitor the external suspension status in real time and give warnings in a timely manner; A flight control module, which is used to generate corresponding flight control adjustment commands according to the external suspension center of gravity position and the predefined ideal center of gravity range.

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