A method and system for monitoring the status of an external sling of a helicopter

Abstract

The application belongs to the technical field of helicopter external hanging state monitoring, and discloses a method and system applied to helicopter external hanging state monitoring, which first establishes a machine body coordinate system with the gravity center of the helicopter as the origin, acquires real-time helicopter positioning data, helicopter attitude angle data and external hanging object positioning data; then calculates the position of the external hanging object in the machine body coordinate system according to the data; then calculates the hanging point position and corrects the position of the external hanging object accordingly; subsequently calculates the actual gravity center position of the external hanging object, judges whether it exceeds the flight envelope of the helicopter; finally, displays a three-dimensional image of the attitude relationship between the external hanging object and the helicopter in real time, if the attitude of the external hanging object exceeds the flight envelope, the helicopter alarms and generates corresponding flight control adjustment instructions to assist the pilot in controlling the helicopter. Through accurate position calculation, dynamic correction mechanism and effective flight control adjustment strategy, the stability, safety and transportation efficiency of the helicopter external hanging are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of helicopter external sling state monitoring, and more particularly, to a helicopter external sling state monitoring method and system. BACKGROUND

[0002] With the rapid development of aviation technology, helicopters are increasingly widely used in various complex environments. Among them, external sling transportation is an important mission of helicopters, and plays a key role in vertical supply, rescue, and material transportation. However, in actual application, helicopter external sling transportation still faces many challenges. Helicopters fly at high speed, the sling produces unsteady aerodynamic load, the aerodynamic characteristics are unstable, the external sling swings irregularly, and the two may appear coupled oscillation. Pilots cannot accurately perceive the relative position relationship and motion between the external sling and the helicopter, and improper operation may seriously affect flight safety. There are significant deficiencies in the current external sling state monitoring and other aspects.

[0003] First, the existing system lacks accuracy in calculating and correcting the position of the external sling. Most systems only rely on GPS positioning data and fail to fully consider the impact of sling swing on the actual position of the external sling, resulting in a deviation between the calculation results and the actual situation. This inaccurate position calculation method is not conducive to stable flight of the helicopter and increases the risk of flight safety. In addition, in the determination of the center of gravity position of the external sling, the existing technology usually equates the installation position of the GPS receiver to the center of gravity of the external sling, 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 sling, thereby affecting the accuracy and effectiveness of subsequent adjustment. Currently, pilots have no effective means to accurately understand the relative position relationship and motion of the helicopter and the external sling, and cannot accurately know the attitude relationship between the external sling and the helicopter, which is prone to misoperation. Finally, these problems comprehensively lead to insufficient stability and safety of the helicopter during external sling transportation, limiting the potential of efficient application of the helicopter in complex environments. SUMMARY

[0004] In order to overcome the problem of insufficient stability and safety of the helicopter during external sling transportation in the prior art, the present application provides a helicopter external sling state monitoring method and system to solve the above problems.

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

[0006] A helicopter external sling state monitoring method, comprising:

[0007] A three-dimensional coordinate system is established with the center of gravity of the helicopter as the origin, and is defined as the body coordinate system; real-time helicopter positioning data, helicopter attitude angle data and external hanging object positioning data are obtained;

[0008] According to the real-time helicopter positioning data, helicopter attitude angle data and external hanging object positioning data, the position of the external hanging object in the body coordinate system is calculated, and is recorded as the external hanging object position;

[0009] Real-time sling swing data is obtained, and according to the sling swing data and the sling length, the position of the hanging point in the body coordinate system is calculated, and is recorded as the hanging point position;

[0010] The external hanging object position is corrected according to the hanging point position, and the corrected external hanging object position is obtained;

[0011] The pre-measured center of gravity offset data is obtained, and the center of gravity position of the external hanging object is obtained according to the corrected external hanging object position and the center of gravity offset data;

[0012] According to the position and attitude relationship between the external hanging object and the helicopter, a three-dimensional image of the attitude relationship between the external hanging object and the helicopter is established, and is displayed in real time on the helicopter integrated display system; if the external hanging object attitude exceeds the flight envelope, the helicopter alarms, and when the relative position relationship between the external hanging 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 alarms;

[0013] According to the center of gravity position of the external hanging object and the pre-defined ideal center of gravity range, corresponding flight control adjustment instructions are generated.

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

[0015] Preferably, the step of calculating the position of the external hanging object in the body coordinate system comprises:

[0016] The GPS coordinates of the helicopter and the GPS coordinates of the external hanging object are converted into coordinates in the geocentric coordinate system;

[0017] The coordinates (X1, Y1, Z1) are obtained from the transformed coordinates; where X1 is obtained by subtracting the helicopter's X-axis coordinate from the X-axis coordinate of the external sling, Y1 is obtained by subtracting the helicopter's Y-axis coordinate from the Y-axis coordinate of the external sling, and Z1 is obtained by subtracting the helicopter's Z-axis coordinate from the Z-axis coordinate of the external sling.

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

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

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

[0021] The first fundamental matrix Rx is constructed using the following formula:

[0022] Where φ represents the pitch angle;

[0023] The second fundamental matrix Ry is constructed using the following formula:

[0024] Where θ represents the roll angle;

[0025] The third fundamental matrix Rz is constructed using the following formula:

[0026] Where ψ represents the yaw angle;

[0027] The transformation matrix R is obtained by performing matrix multiplication operations on the first basic matrix Rx, the second basic matrix Ry, and the third basic matrix Rz in sequence.

[0028] Preferably, the sling swing data includes the sling swing angle and swing direction angle, which are acquired by angle sensors and direction sensors installed on the sling;

[0029] The steps for calculating the position of the suspension point in the body coordinate system include:

[0030] The swing angle is decomposed into X-axis and Y-axis components using 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] Based on the swing angle of the sling length, the X-axis component, and the Y-axis 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;

[0034] Multiplying (X3,Y3,Z3) by the transformation matrix R yields (X4,Y4,Z4), which represents the position of the hanging point in the body coordinate system. Here, X4 represents the X-axis coordinate, Y4 represents the Y-axis coordinate, and Z4 represents the Z-axis coordinate.

[0035] Preferably, the step of correcting the position of the externally suspended object based on the position of the hanging point to obtain the corrected position of the externally suspended object includes:

[0036] The corrected coordinates (X5, Y5, Z5) of the externally suspended object in the body coordinate system are calculated using the following formula:

[0037] (X5,Y5,Z5) represents the correction of the external hanging position, and q represents the preset adjustment coefficient.

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

[0039] The process of obtaining the center of gravity position of the externally suspended object based on the corrected position and center of gravity offset data includes:

[0040] The coordinates (X6, Y6, Z6) of the center of gravity of the externally suspended object in the body coordinate system are calculated using the following formula;

[0041] (X6,Y6,Z6) represents the position of the center of gravity of the externally suspended object.

[0042] Preferably, the step of generating corresponding adjustment commands based on the center of gravity position of the externally suspended object and a predefined ideal center of gravity range includes:

[0043] The position deviation vector is obtained based on the latest center of gravity position of the externally suspended object and the ideal center of gravity position. The position deviation vector includes X-axis deviation, Y-axis deviation and Z-axis deviation.

[0044] The motion trend index vector of the externally suspended object is obtained based on the center of gravity position of the externally suspended object in at least one recent motion cycle. The motion trend index vector includes an X-axis motion trend index, a Y-axis motion trend index, and a Z-axis motion trend index.

[0045] Generate corresponding pitch angle adjustment commands based on X-axis deviation and X-axis motion trend indicators;

[0046] Generate corresponding roll angle adjustment commands based on Y-axis deviation and Y-axis motion trend indicators;

[0047] Generate corresponding collective pitch adjustment commands based on Z-axis deviation and Z-axis motion trend indicators;

[0048] Pitch angle adjustment command, roll angle adjustment command, and collective pitch adjustment command constitute the flight control adjustment command.

[0049] The present invention also provides a system for monitoring the status of external slings on helicopters, and a method for monitoring the status of external slings on helicopters, comprising:

[0050] The coordinate system establishment and data acquisition module is used to establish a three-dimensional coordinate system with the helicopter's center of gravity as the origin and define it as the body coordinate system; it acquires real-time helicopter positioning data, helicopter attitude angle data, and external sling location data.

[0051] The external attachment position calculation module is used to calculate the position of the external attachment in the aircraft coordinate system based on real-time helicopter positioning data, attitude data and external attachment positioning data, and record it as the external attachment position;

[0052] The suspension point position calculation module is used to acquire real-time sling swing data, calculate the position of the suspension point in the machine coordinate system based on the sling swing data and sling length, and record it as the suspension point position;

[0053] The external hanging object position correction module is used to correct the position of the external hanging object based on the position of the hanging point, so as to obtain the corrected position of the external hanging object;

[0054] The center of gravity position calculation module is used to obtain the pre-measured center of gravity offset data and obtain the center of gravity position of the external hanging object based on the corrected position of the external hanging object and the center of gravity offset data;

[0055] The status monitoring and alarm module is used to establish a three-dimensional image of the attitude relationship between the externally suspended object and the helicopter in the integrated display system based on the center of gravity position of the externally suspended object and the predefined ideal center of gravity range, and to monitor the status of the externally suspended object in real time and issue alarms as appropriate.

[0056] The flight control module is used to generate corresponding flight control adjustment commands based on the center of gravity position of the externally suspended object and a predefined ideal center of gravity range.

[0057] This invention provides a method and system for monitoring the status of external slings on helicopters, which has the following beneficial effects:

[0058] By establishing a three-dimensional coordinate system with the helicopter as the origin and comprehensively utilizing helicopter positioning data, helicopter attitude angle data, and externally attached object (OPA) positioning data, accurate calculation of the OPA's position is achieved, overcoming the limitations of traditional GPS-only positioning. The introduction of sling swing data and sling length data to correct the OPA's position effectively considers the impact of sling dynamics on the OPA's actual position, making the position calculation closer to reality. Simultaneously, by incorporating pre-measured center of gravity offset data, accurate conversion from the GPS receiver position to the OPA's actual center of gravity position is achieved, overcoming the simplistic approach of equating the GPS receiver position with the OPA's center of gravity. By calculating the position deviation vector and trend index vector, the current deviation and changing trend of the OPA's center of gravity position are comprehensively considered, overcoming the limitations of traditional methods that rely solely on static position judgment and enabling more intelligent generation of flight control adjustment commands. By establishing a three-dimensional image of the attitude relationship between the external sling and the helicopter, and displaying it in real time on an integrated display system, the problem of the pilot's inability to accurately perceive the attitude of the external sling is solved. By generating adjustment commands for pitch, roll, and collective pitch, all-around adjustment of the helicopter's attitude is achieved, overcoming the limitations of single-direction adjustment and enabling a more comprehensive response to complex changes in the center of gravity. Overall, the method proposed in this invention improves the stability, safety, and transport efficiency of helicopter external slings through precise position calculation, dynamic correction mechanisms, and effective adjustment strategies. Attached Figure Description

[0059] Figure 1 This is a flowchart illustrating a method for monitoring the status of externally mounted equipment on a helicopter according to the present invention.

[0060] Figure 2 This is a schematic diagram of the modules of the helicopter external sling status monitoring system of the present invention. Detailed Implementation

[0061] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0062] Example 1

[0063] Please see Figure 1 In this embodiment, a method for monitoring the status of external slings on 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; acquire real-time helicopter positioning data, helicopter attitude angle data, and external sling location data;

[0065] The aircraft coordinate system has the helicopter's center of gravity as its origin, with the X-axis pointing towards the nose, the Y-axis pointing towards the right side of the helicopter, and the Z-axis pointing towards the ground. The helicopter's positioning data consists of its GPS coordinates, acquired through a GPS system installed on the helicopter. The helicopter's attitude angle data includes pitch, roll, and yaw angles, measured by an inertial measurement system installed on the helicopter. The external sling location data consists of the GPS coordinates of the external sling, acquired through a GPS system installed on the external sling.

[0066] In this embodiment, establishing a three-dimensional coordinate system with the helicopter's center of gravity as the origin and acquiring relevant data can be performed according to the following steps: First, a high-precision inertial measurement system (IMU) is installed on the helicopter. This system typically includes an accelerometer, a gyroscope, and a magnetometer. Next, the location of the helicopter's center of gravity is used as the origin of the body coordinate system. The three axes of the helicopter body coordinate system are defined: the X-axis points towards the nose, the Y-axis points towards the right side of the helicopter body, and the Z-axis points towards the ground. This establishes a three-dimensional coordinate system with the helicopter's center of gravity as the origin.

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

[0068] For acquiring helicopter attitude angle data, an installed IMU system is used. By fusing data from accelerometers, gyroscopes, and magnetometers, the IMU can calculate the helicopter's pitch, roll, and yaw angles in real time. These angle data are typically output in Euler angles.

[0069] Finally, an independent GPS receiver is installed on the externally attached object to acquire its real-time positioning data. This GPS receiver is typically mounted on the top of the externally attached object or in another location easily accessible for satellite signals. Similarly, DGPS or RTK technology can be used to improve positioning accuracy. To synchronize and process this data, a central processing unit (CPU) can be installed on the helicopter. This CPU receives data from the helicopter's GPS and IMU via a wired connection and receives GPS data from the externally attached object via wireless communication. The CPU simultaneously acquires data from all sensors at a fixed frequency (e.g., 10Hz) to ensure data consistency. Through these steps, the aircraft coordinate system is established, and real-time helicopter positioning data, helicopter attitude angle data, and externally attached object positioning data are acquired. This data provides the foundation for subsequent coordinate transformations and position calculations.

[0070] S2. Based on real-time helicopter positioning data, helicopter attitude angle data, and external hanging object positioning data, calculate the position of the external hanging object in the aircraft coordinate system and record it as the external hanging object position.

[0071] The steps for calculating the position of the externally suspended object in the body coordinate system include:

[0072] Convert the GPS coordinates of the helicopter and the externally mounted objects into coordinates in the geocentric coordinate system;

[0073] The coordinates (X1, Y1, Z1) are obtained from the transformed coordinates; where X1 is obtained by subtracting the helicopter's X-axis coordinate from the X-axis coordinate of the external sling, Y1 is obtained by subtracting the helicopter's Y-axis coordinate from the Y-axis coordinate of the external sling, and Z1 is obtained by subtracting the helicopter's Z-axis coordinate from the Z-axis coordinate of the external sling.

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

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

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

[0077] The first fundamental matrix Rx is constructed using the following formula:

[0078] Where φ represents the pitch angle;

[0079] The second fundamental matrix Ry is constructed using the following formula:

[0080] Where θ represents the roll angle;

[0081] The third fundamental matrix Rz is constructed using the following formula:

[0082] Where ψ represents the yaw angle;

[0083] The transformation matrix R is obtained by performing matrix multiplication operations on the first basic matrix Rx, the second basic matrix Ry, and the third basic matrix Rz in sequence.

[0084] In this embodiment, the position of the externally suspended object in the body coordinate system can be calculated according to the following steps:

[0085] First, the GPS coordinates of the helicopter and external slinger are converted to geocentrically fixed (ECEF) coordinates using the WGS84 coordinate transformation algorithm. Next, the position vector of the external slinger relative to the helicopter is obtained by calculating the difference between the ECEF coordinates of the external slinger and the helicopter. Then, based on the helicopter's attitude angle data (including pitch, roll, and yaw angles), three basic rotation matrices are constructed. Following the usual order of yaw, then pitch, and finally roll, these three matrices are multiplied sequentially to obtain the final transformation matrix. This step can be performed using a specialized matrix operation library to improve computational efficiency and accuracy.

[0086] Finally, the resulting transformation matrix is ​​multiplied by the relative position vector. Similarly, this step can be performed using a specialized computation library to improve the efficiency and accuracy of the mathematical calculations. The result of the calculation is the position coordinate of the externally suspended object in the body coordinate system.

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

[0088] The sling swing data includes the sling swing angle and swing direction angle, which are acquired by 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 X-axis and Y-axis components using the following formula;

[0091]

[0092] 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;

[0093] Based on the swing angle of the sling length, the X-axis component, and the Y-axis 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] Multiplying (X3,Y3,Z3) by the transformation matrix R yields (X4,Y4,Z4), which represents the position of the hanging point in the body coordinate system. Here, X4 represents the X-axis coordinate, Y4 represents the Y-axis coordinate, and Z4 represents the Z-axis coordinate.

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

[0096] First, angle and direction sensors mounted on the sling acquire real-time data on the sling's swing. This data includes the sling's swing angle and swing direction angle. High-precision inclinometers can be used as angle sensors, while electronic compasses can be used as direction sensors. Next, using the acquired swing angle and swing direction angle, the swing angle is decomposed into X-axis and Y-axis components. This step uses trigonometric functions; this decomposition method transforms the three-dimensional swing into two planar components, facilitating subsequent calculations. Then, based on the sling length, swing angle, and the calculated X-axis and Y-axis components, the position of the suspension point relative to the helicopter is calculated.

[0097] Finally, multiplying the relative position coordinates obtained in the previous step by the transformation matrix on the left yields the position of the attachment point in the body coordinate system. The transformation matrix used here is the same matrix used when calculating the position of the external attachment.

[0098] S4. Correct the position of the externally suspended object based on the position of the hanging point to obtain the corrected position of the externally suspended object;

[0099] The step of correcting the position of the externally suspended object based on the location of the hanging point to obtain the corrected position of the externally suspended object includes:

[0100] The corrected coordinates (X5, Y5, Z5) of the externally suspended object in the body coordinate system are calculated using the following formula:

[0101] (X5,Y5,Z5) represents the correction of the external hanging position, and q represents the preset adjustment coefficient.

[0102] In this embodiment, the process of correcting the position of the externally suspended object based on the location of the hanging point can be performed according to the following steps:

[0103] First, obtain the coordinates of the previously calculated external attachment position and attachment point position in the body coordinate system. Both positions are three-dimensional coordinates, containing X, Y, and Z components respectively. Next, a correction formula is used to calculate the corrected external attachment position. Taking the X-axis as an example, the corrected external attachment X-coordinate is equal to the original external attachment X-coordinate plus (the difference between the attachment point X-coordinate and the external attachment X-coordinate) divided by a preset value q. In this example, q is set to 2. The correction method for the Y and Z axes is the same as for the X-axis. This method calculates the corrected position of the externally suspended object by considering the influence of the sling on its position and simulating the actual effect of the object being pulled towards the suspension point. It also boasts strong real-time performance, allowing for immediate correction calculations upon acquiring new position data, eliminating the need for complex iterative processes and enabling rapid response to positional changes caused by sling swing. Furthermore, by adjusting the q-value, this method offers high flexibility, controlling the degree of correction to adapt to different suspension conditions and the characteristics of the externally suspended object. A smaller q-value results in a larger correction, bringing the externally suspended object closer to the suspension point, and vice versa. The corrected position of the externally suspended object more accurately reflects its actual location. Through this correction, a more accurate and real-time estimate of the externally suspended object's 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 hanging object based on the corrected position of the external hanging object and the center of gravity offset data;

[0105] The center of gravity offset data is (ΔX, ΔY, ΔZ), where ΔX is the distance between the GPS system position installed on the external suspended object and the center of gravity of the external suspended object in the geocentric-ground-fixed coordinate system under the X-axis, ΔY is the distance between the GPS system position installed on the external suspended object and the center of gravity of the external suspended object in the geocentric-ground-fixed coordinate system under the Y-axis, and ΔZ is the distance between the GPS system position installed on the external suspended object and the center of gravity of the external suspended object in the geocentric-ground-fixed coordinate system under the Y-axis.

[0106] The process of obtaining the center of gravity position of the externally suspended object based on the corrected position and center of gravity offset data includes:

[0107] The coordinates (X6, Y6, Z6) of the center of gravity of the externally suspended object in the body coordinate system are calculated using the following formula;

[0108] (X6,Y6,Z6) represents the position of the center of gravity of the externally suspended object.

[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 externally suspended object is as follows:

[0110] First, pre-measured center of gravity offset data is acquired. This data reflects the distance difference between the GPS system position mounted on the external suspension and the actual center of gravity of the external suspension. Specifically, it includes the distance differences in the X, Y, and Z axes in the geocentric coordinate system. This data is typically obtained through precise measurements before the external suspension is loaded and stored in the form of (ΔX, ΔY, ΔZ).

[0111] Next, the corrected position and center of gravity offset data of the externally suspended object are used to calculate the actual center of gravity position of the externally suspended object. Since positioning devices (such as GPS receivers) are typically difficult to install at the precise center of gravity of the externally suspended object, the previously calculated position was actually the position of the positioning device, not the true center of gravity position of the externally suspended object. By incorporating this pre-measured deviation, the actual position of the externally suspended object's center of gravity can be estimated more accurately, providing accurate data reference for subsequent center of gravity adjustments.

[0112] S6. Generate corresponding flight control adjustment commands based on the center of gravity position of the externally suspended object and the predefined ideal center of gravity range.

[0113] The step of generating corresponding flight control adjustment commands based on the center of gravity position of the externally suspended object and a predefined ideal center of gravity range includes:

[0114] The position deviation vector is obtained based on the latest center of gravity position of the externally suspended object and the ideal center of gravity position. The position deviation vector includes X-axis deviation, Y-axis deviation and Z-axis deviation.

[0115] The motion trend index vector of the externally suspended object is obtained based on the center of gravity position of the externally suspended object in at least one recent motion cycle. The motion trend index vector includes an X-axis motion trend index, a Y-axis motion trend index, and a Z-axis motion trend index.

[0116] Generate corresponding pitch angle adjustment commands based on X-axis deviation and X-axis motion trend indicators;

[0117] Generate corresponding roll angle adjustment commands based on Y-axis deviation and Y-axis motion trend indicators;

[0118] Generate corresponding collective pitch adjustment commands based on Z-axis deviation and Z-axis motion trend indicators;

[0119] Pitch angle adjustment command, roll angle adjustment command, and collective pitch adjustment command constitute the flight control adjustment command.

[0120] In this embodiment, the process of generating adjustment commands based on the center of gravity position of the externally suspended object and a predefined ideal center of gravity range is as follows:

[0121] First, an ideal center of gravity position is predefined. This position can be calculated in advance and ensures the helicopter remains stable under various flight conditions. Next, data on the center of gravity position of the externally slung object is continuously collected at multiple time points (at least one motion cycle).

[0122] Next, the position deviation vector and trend index vector are calculated. The position deviation vector is the difference between the latest sampling point and the ideal position, including deviations in the X, Y, and Z axes. The motion trend index vector is obtained through linear regression analysis of multiple consecutive sampling points, reflecting the changing trend of the center of gravity of the externally suspended object in the three directions. Then, based on the position deviation and motion trend index, it is determined whether adjustment is needed, and corresponding adjustment commands are generated. Specifically:

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

[0124] For the Y-axis direction, a similar method is used to generate roll angle adjustment commands. When the Y-axis motion trend indicator and position deviation have the same sign and both exceed their respective thresholds, the roll angle needs to be increased; conversely, the roll angle needs to be decreased.

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

[0126] Finally, the generated pitch, roll, and collective pitch control commands are combined into the final flight control control commands. This method considers not only the deviation between the current position and the ideal position but also the trend of position changes, enabling more intelligent adjustments. By using preset thresholds, frequent adjustments due to minor fluctuations can be avoided, while timely responses to significant position changes are possible. This method helps helicopters maintain stability in complex flight environments, improving flight stability and safety.

[0127] Example 2

[0128] Please see Figure 2 This invention provides a system for monitoring the status of external slings on helicopters, and a method for monitoring the status of external slings on helicopters, comprising:

[0129] The coordinate system establishment and data acquisition module is used to establish a three-dimensional coordinate system with the helicopter's center of gravity as the origin and define it as the body coordinate system; it acquires real-time helicopter positioning data, helicopter attitude angle data, and external sling location data.

[0130] The external attachment position calculation module is used to calculate the position of the external attachment in the aircraft coordinate system based on real-time helicopter positioning data, helicopter attitude angle data and external attachment positioning data, and record it as the external attachment position.

[0131] The suspension point position calculation module is used to acquire real-time sling swing data, calculate the position of the suspension point in the machine coordinate system based on the sling swing data and sling length, and record it as the suspension point position;

[0132] The external hanging object position correction module is used to correct the position of the external hanging object based on the position of the hanging point, so as to obtain the corrected position of the external hanging object;

[0133] The center of gravity position calculation module is used to obtain the pre-measured center of gravity offset data and obtain the center of gravity position of the external hanging object based on the corrected position of the external hanging object and the center of gravity offset data;

[0134] The status monitoring and alarm module is used to establish a three-dimensional image of the attitude relationship between the externally suspended object and the helicopter in the integrated display system based on the center of gravity position of the externally suspended object and the predefined ideal center of gravity range, and to monitor the status of the externally suspended object in real time and issue alarms as appropriate.

[0135] The flight control module is used to generate corresponding flight control adjustment commands based on the center of gravity position of the externally suspended object and a predefined ideal center of gravity range.

[0136] This invention significantly improves the stability, safety, and transport efficiency of external sling loads on helicopters through precise position calculation, dynamic correction mechanisms, and effective flight control adjustment strategies.

[0137] In the several embodiments provided by this invention, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only one method, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0138] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

[0139] In conclusion, the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for monitoring the status of external slings mounted on a helicopter, characterized in that, include: Establish a three-dimensional coordinate system with the helicopter's center of gravity as the origin, and define it as the body coordinate system; acquire real-time helicopter positioning data, helicopter attitude angle data, and external sling location data; Based on real-time helicopter positioning data, helicopter attitude angle data, and external hanging object positioning data, calculate the position of the external hanging object in the aircraft coordinate system and record it as the external hanging object position; Acquire real-time sling swing data, calculate the position of the suspension point in the machine coordinate system based on the sling swing data and sling length, and record it as the suspension point position; The position of the externally suspended object is adjusted based on the location of the hanging point to obtain the corrected position of the externally suspended object. Obtain the pre-measured center of gravity offset data, and obtain the center of gravity position of the external hanging object based on the corrected position of the external hanging object and the center of gravity offset data; Based on the actual center of gravity position of the externally suspended object and the predefined ideal center of gravity range, determine whether the attitude of the externally suspended object exceeds the flight envelope; If the attitude of the externally slung object exceeds the flight envelope, the helicopter will issue an alarm and generate corresponding flight control adjustment commands based on the actual center of gravity position of the externally slung object and the predefined ideal center of gravity range to assist the pilot in controlling the helicopter.

2. The method for monitoring the status of external slings on a helicopter according to claim 1, characterized in that, The aircraft coordinate system has the helicopter's center of gravity as its origin, with the X-axis pointing towards the nose, the Y-axis pointing towards the right side of the helicopter body, and the Z-axis pointing towards the ground. The helicopter's positioning data consists of its GPS coordinates, acquired through a GPS system installed on the helicopter. The helicopter's attitude angle data includes pitch, roll, and yaw angles, measured by an inertial measurement system installed on the helicopter. The external sling location data consists of the GPS coordinates of the external sling, acquired through a GPS system installed on the external sling.

3. The method for monitoring the status of external slings on a helicopter according to claim 2, characterized in that, The steps for calculating the position of the externally suspended object in the body coordinate system include: Convert the GPS coordinates of the helicopter and the externally mounted objects into coordinates in the geocentric coordinate system; The coordinates (X1, Y1, Z1) are obtained from the transformed coordinates; where X1 is obtained by subtracting the helicopter's X-axis coordinate from the X-axis coordinate of the external sling, Y1 is obtained by subtracting the helicopter's Y-axis coordinate from the Y-axis coordinate of the external sling, and Z1 is obtained by subtracting the helicopter's Z-axis coordinate from the Z-axis coordinate of the external sling. Calculate the transformation matrix R based on the helicopter attitude angle data; Multiply (X1,Y1,Z1) by the transformation matrix R to obtain (X2,Y2,Z2). Use (X2,Y2,Z2) to represent the position of the external hanging object in the body coordinate system, where X2 represents the X-axis coordinate, Y2 represents the Y-axis coordinate, and Z2 represents the Z-axis coordinate.

4. The method for monitoring the status of external slings on a helicopter according to claim 3, characterized in that, The step of calculating the transformation matrix R based on the helicopter attitude angle data includes: The first fundamental matrix Rx is constructed using the following formula: Where φ represents the pitch angle; The second fundamental matrix Ry is constructed using the following formula: Where θ represents the roll angle; The third fundamental matrix Rz is constructed using the following formula: Where ψ represents the yaw angle; The transformation matrix R is obtained by performing matrix multiplication operations on the first basic matrix Rx, the second basic matrix Ry, and the third basic matrix Rz in sequence.

5. The method for monitoring the status of external slings on a helicopter according to claim 4, characterized in that, The sling swing data includes the sling swing angle and swing direction angle, which are acquired by angle sensors and direction sensors installed on the sling. The steps for calculating the position of the suspension point in the body coordinate system include: The swing angle is decomposed into X-axis and Y-axis components using the following formula; 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; Based on the swing angle of the sling length, the X-axis component, and the Y-axis 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; Multiplying (X3,Y3,Z3) by the transformation matrix R yields (X4,Y4,Z4), which represents the position of the hanging point in the body coordinate system. Here, X4 represents the X-axis coordinate, Y4 represents the Y-axis coordinate, and Z4 represents the Z-axis coordinate.

6. The method for monitoring the status of external slings on a helicopter according to claim 5, characterized in that, The step of correcting the position of the externally suspended object based on the location of the hanging point to obtain the corrected position of the externally suspended object includes: The corrected coordinates (X5, Y5, Z5) of the externally suspended object in the body coordinate system are calculated using the following formula: (X5,Y5,Z5) represents the correction of the external hanging position, and q represents the preset adjustment coefficient.

7. The method for monitoring the status of external slings on a helicopter according to claim 6, characterized in that, The center of gravity offset data is (ΔX, ΔY, ΔZ), where ΔX is the distance between the GPS system position installed on the external suspended object and the center of gravity of the external suspended object in the geocentric-geocentric coordinate system (X-axis), ΔY is the distance between the GPS system position installed on the external suspended object and the center of gravity of the external suspended object in the geocentric-geocentric coordinate system (Y-axis), and ΔZ is the distance between the GPS system position installed on the external suspended object and the center of gravity of the external suspended object in the geocentric-geocentric coordinate system (Z-axis). The process of obtaining the center of gravity position of the externally suspended object based on the corrected position and center of gravity offset data includes: The coordinates (X6, Y6, Z6) of the center of gravity of the externally suspended object in the body coordinate system are calculated using the following formula; (X6,Y6,Z6) represents the position of the center of gravity of the externally suspended object.

8. The method for monitoring the status of external slings on a helicopter according to claim 7, characterized in that, Based on the position and attitude relationship between the externally attached object and the helicopter, a three-dimensional image of the attitude relationship between the externally attached object and the helicopter is established in the helicopter integrated display system. If the attitude of the externally attached object exceeds the flight envelope, the helicopter will issue an alarm. When the relative position relationship between the externally attached object and the helicopter is within the ideal center of gravity range, the three-dimensional image on the integrated display system screen is green; when it is at the boundary of the ideal center of gravity range, the three-dimensional image on the integrated display system screen is yellow; when it exceeds the ideal center of gravity range, the three-dimensional image on the integrated display system screen is red, and the helicopter will issue a voice alarm.

9. A method for monitoring the status of external slings on a helicopter according to claim 7, characterized in that, The step of generating corresponding flight control adjustment commands based on the center of gravity position of the externally suspended object and a predefined ideal center of gravity range includes: The position deviation vector is obtained based on the latest center of gravity position of the externally suspended object and the ideal center of gravity position. The position deviation vector includes X-axis deviation, Y-axis deviation and Z-axis deviation. The motion trend index vector of the externally suspended object is obtained based on the center of gravity position of the externally suspended object in at least one recent motion cycle. The trend index vector includes an X-axis motion trend index, a Y-axis motion trend index, and a Z-axis motion trend index. Generate corresponding pitch angle adjustment commands based on X-axis deviation and X-axis motion trend indicators; Generate corresponding roll angle adjustment commands based on Y-axis deviation and Y-axis motion trend indicators; Generate corresponding collective pitch adjustment commands based on Z-axis deviation and Z-axis motion trend indicators; Pitch angle adjustment command, roll angle adjustment command, and collective pitch adjustment command constitute the flight control adjustment command.

10. A system for monitoring the status of external slings on a helicopter, used to implement the method for monitoring the status of external slings on a helicopter as described in any one of claims 1-8, characterized in that, include: The coordinate system establishment and data acquisition module is used to establish a three-dimensional coordinate system with the helicopter's center of gravity as the origin and define it as the body coordinate system; it acquires real-time helicopter positioning data, helicopter attitude angle data, and external sling location data. The external attachment position calculation module is used to calculate the position of the external attachment in the aircraft coordinate system based on real-time helicopter positioning data, helicopter attitude angle data and external attachment positioning data, and record it as the external attachment position. The suspension point position calculation module is used to acquire real-time sling swing data, calculate the position of the suspension point in the machine coordinate system based on the sling swing data and sling length, and record it as the suspension point position; The external hanging object position correction module is used to correct the position of the external hanging object based on the position of the hanging point, so as to obtain the corrected position of the external hanging object; The center of gravity position calculation module is used to obtain the pre-measured center of gravity offset data and obtain the center of gravity position of the external hanging object based on the corrected position of the external hanging object and the center of gravity offset data; The status monitoring and alarm module is used to establish a three-dimensional image of the attitude relationship between the externally suspended object and the helicopter in the helicopter integrated display system based on the center of gravity position of the externally suspended object and the predefined ideal center of gravity range, and to monitor the status of the externally suspended object in real time and issue alarms as appropriate. The flight control module is used to generate corresponding flight control adjustment commands based on the center of gravity position of the externally suspended object and a predefined ideal center of gravity range.

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