Airflow detection and obstacle avoidance system and obstacle avoidance control method based on rotary-wing UAV

Abstract

This invention discloses an airflow detection and obstacle avoidance system and method based on a rotary-wing unmanned aerial vehicle (UAV). The system includes a controlled UAV, an airflow detection and analysis module disposed around the UAV's fuselage, used to detect changes in the airflow field around the UAV's fuselage, analyze the detected airflow field changes, determine the presence of obstacles around the UAV's fuselage, and determine the location of any obstacles. A flight control module is disposed on the UAV's fuselage and connected to the airflow detection and analysis module. The flight control module replans the UAV's path based on the location information of obstacles around the fuselage sent by the airflow detection and analysis module, controls the UAV to adjust the rotational speed ratio of each rotor, adjusts the fuselage attitude and flight path, and performs obstacle avoidance. This invention detects obstacles quickly and sensitively by using airflow field information around the UAV's fuselage.

Description

Technical Field

[0001] This invention relates to the field of intelligent systems technology, and in particular to an airflow detection and obstacle avoidance system and obstacle avoidance control method based on a rotary-wing unmanned aerial vehicle (UAV). Background Technology

[0002] Currently, drone obstacle avoidance systems lack direct, rapid, and simple detection methods. Existing drone obstacle avoidance systems primarily employ optical detection methods and path planning approaches. Optical detection methods, such as lidar and optical sensors, collect complex information, often requiring remote transmission to the cloud or user terminal for obstacle location determination. However, this method involves long communication links and complex processing. Furthermore, optical detection is an active method, limiting its capabilities in specific scenarios, such as low visibility conditions like nighttime or fog, or when obstacles are transparent. Path planning methods require pre-constructed flight maps and lack detection and handling mechanisms for sudden obstacles during flight. Therefore, existing drone obstacle avoidance systems based on optical detection and path planning struggle to meet the requirements for real-time flow field detection by drones.

[0003] Therefore, existing sensor technologies still need further improvement and development. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the purpose of this invention is to provide an airflow detection and obstacle avoidance system and obstacle avoidance control method based on a rotary-wing UAV. The present invention provides an airflow detection and obstacle avoidance system based on a rotary-wing UAV, which aims to solve the problems of complex detection and lack of flow field perception capability in the prior art UAV obstacle avoidance system.

[0005] The technical solution of the present invention is as follows:

[0006] A first aspect of the present invention provides an airflow detection and obstacle avoidance system based on a rotary-wing unmanned aerial vehicle, comprising:

[0007] Controlled drone,

[0008] The airflow detection and analysis module is set around the body of the controlled drone to detect changes in the airflow field around the drone, analyze the detected changes in the airflow field, determine whether there are obstacles around the drone, and determine the location of the obstacles.

[0009] A flight control module is installed on the body of the controlled UAV and connected to the airflow detection and analysis module. The flight control module is used to replan the path of the controlled UAV based on the position information of obstacles around the body sent by the airflow detection and analysis module, and control the controlled UAV to adjust the speed ratio of each rotor, adjust the body attitude and flight path to avoid obstacles.

[0010] The airflow detection and obstacle avoidance system based on a rotary-wing UAV is described above, wherein the airflow detection and analysis module is installed on the lower part of the controlled UAV body by means of pasting, screw fastening or clipping.

[0011] The aforementioned airflow detection and obstacle avoidance system based on a rotary-wing UAV, wherein the airflow detection and analysis module includes:

[0012] Airflow conversion module;

[0013] A guide tube connected to the airflow conversion module is used to introduce airflow;

[0014] A biomimetic bidirectional airflow and pressure sensor is installed on the airflow conversion module.

[0015] And a signal processing and analysis circuit connected to the biomimetic bidirectional airflow pressure sensor;

[0016] The guiding air tube is used to introduce airflow information from a specific location on the UAV body into the air chamber where the biomimetic bidirectional airflow and pressure sensor is located on the airflow conversion module;

[0017] The airflow conversion module contains an air passage that introduces external airflow information into the air cavity where the biomimetic bidirectional airflow pressure sensor is located.

[0018] The airflow conversion module and the bionic bidirectional airflow pressure sensor are sealed with sealing rings between the air chambers and between the air chambers and the air passages. The bionic bidirectional airflow pressure sensor is used to respond to the introduced airflow information. When the aircraft encounters an obstacle in the flight direction, the airflow at the corresponding position changes. The change in airflow causes the sensitive structure of the bionic bidirectional airflow pressure sensor to deform and outputs the change signal to the signal processing and analysis circuit.

[0019] The signal processing and analysis circuit is used to filter and amplify the changing signals output by the biomimetic bidirectional airflow pressure sensor; and when the signal processing and analysis circuit analyzes that the airflow information of a certain biomimetic bidirectional airflow pressure sensor suddenly changes, it analyzes the signal change to obtain the corresponding position between the obstacle and the aircraft, and transmits the position information of the obstacle to the flight control module.

[0020] The airflow detection and obstacle avoidance system based on a rotary-wing UAV is described above, wherein the guide air pipe has an opening at one end facing the outside of the body, and the opening is located on the outside of the controlled UAV body and / or facing the upper part of the body.

[0021] In the aforementioned airflow detection and obstacle avoidance system based on a rotary-wing UAV, the guide air tube is fixed to the airflow conversion module using adhesive, bayonet, or spiral fastening.

[0022] The airflow detection and obstacle avoidance system based on a rotary-wing UAV includes an airflow conversion module comprising an upper cover plate and a lower cover plate, wherein the biomimetic bidirectional airflow pressure sensor and signal processing and analysis circuit are disposed between the upper cover plate and the lower cover plate; the upper cover plate and the lower cover plate are combined by means of screw fastening; the biomimetic bidirectional airflow pressure sensor is soldered on the circuit board where the signal processing and analysis circuit is located;

[0023] The airflow conversion module contains an air guiding channel between the upper and lower cover plates to transmit airflow information to the location of the biomimetic bidirectional airflow pressure sensor. The upper and lower cover plates of the airflow conversion module have cavities near the biomimetic bidirectional airflow pressure sensor.

[0024] The airflow detection and obstacle avoidance system based on a rotary-wing UAV, wherein the airflow detection and analysis module includes at least one air duct and at least one biomimetic bidirectional airflow and pressure sensor;

[0025] The airflow information at positions 45 degrees or higher relative to each other in the airflow detection and analysis module is detected by a biomimetic bidirectional airflow and pressure sensor.

[0026] The aforementioned airflow detection and obstacle avoidance system based on a rotary-wing UAV includes a biomimetic bidirectional airflow and pressure sensor that can detect information from multiple air passages. Multiple biomimetic bidirectional airflow and pressure sensors cooperate to form a biomimetic bidirectional airflow and pressure sensor array, which is used to realize sensor encoding of complex obstacles around the UAV body.

[0027] The biomimetic bidirectional airflow and pressure sensor array employs different encoding methods to detect multiple obstacles.

[0028] The airflow detection and obstacle avoidance system based on a rotary-wing UAV includes a biomimetic bidirectional airflow sensor comprising: a sensor base, a crossbeam structure disposed in the middle of the sensor base, a crossbeam center disposed at the intersection of the crossbeam structure, a biomimetic slit structure disposed on one side of the crossbeam center, a resistor surrounding the biomimetic slit structure, and a circuit connected to the resistor.

[0029] The center of the cross beam is set as an enlarged area that is larger than the center area of ​​the cross beam structure;

[0030] The biomimetic seam structure is located at the position of maximum stress outside the expanded area at the center of the cross beam structure.

[0031] An obstacle avoidance control method for an airflow detection obstacle avoidance system based on a rotary-wing unmanned aerial vehicle as described in any one of the claims, comprising the steps of:

[0032] The control system uses an airflow detection and analysis module set around the controlled drone to detect changes in the airflow field around the drone, analyze the detected changes in the airflow field, determine whether there are obstacles around the drone, and determine the location of the obstacles.

[0033] The flight control module, located on the body of the controlled UAV, replans the path of the controlled UAV based on the location information of obstacles around the body sent by the airflow detection and analysis module. It controls the controlled UAV to adjust the speed ratio of each rotor, adjust the body attitude and flight path to avoid obstacles.

[0034] Beneficial Effects: This invention provides an airflow detection and obstacle avoidance system and method based on a rotary-wing UAV. During UAV flight, obstacles around the aircraft affect the flow field. The flow field information is transmitted to a biomimetic bidirectional airflow and pressure sensor via the guiding air duct and airflow conversion module of the airflow detection and obstacle avoidance system. This biomimetic bidirectional airflow and pressure sensor includes an enlarged central structure and a biomimetic slit structure, capable of responding to minute changes in bidirectional airflow. The sensor detects the flow field information around the UAV, and the position of obstacles around the UAV is obtained through a signal processing and analysis module. The flight control module then controls the UAV's flight. By using a flow field approach to detect obstacles around the UAV, and with on-board signal processing, complex signal transmission processes are eliminated, enabling rapid signal processing and improving signal detection and judgment speed. This gives the UAV obstacle avoidance system the ability to quickly detect flow field information. The flow field-based obstacle detection method allows the system to be applied in scenarios where optical detection is limited. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of an airflow detection and obstacle avoidance system based on a rotary-wing unmanned aerial vehicle (UAV) according to an embodiment of the present invention.

[0036] Figure 2 This is a schematic diagram of the airflow detection and analysis module of an airflow detection and obstacle avoidance system based on a rotary-wing UAV, according to an embodiment of the present invention.

[0037] Figure 3 This is a schematic diagram of the airflow detection and analysis module air duct and corresponding sensor distribution of an airflow detection and obstacle avoidance system based on a rotary-wing UAV according to an embodiment of the present invention.

[0038] Figure 4 This is a schematic diagram of a biomimetic bidirectional airflow pressure sensor for an airflow detection and obstacle avoidance system based on a rotary-wing UAV, according to an embodiment of the present invention.

[0039] Figure 5 This is a schematic diagram of the force on a biomimetic bidirectional airflow pressure sensor of an airflow detection and obstacle avoidance system based on a rotary-wing UAV, according to an embodiment of the present invention. Detailed Implementation

[0040] This invention provides an airflow detection and obstacle avoidance system and obstacle avoidance control method based on a rotary-wing unmanned aerial vehicle (UAV). To make the objectives, technical solutions, and effects of this invention clearer and more explicit, the invention is further described in detail below. It should be understood that the specific embodiments described herein are only for explaining the invention and are not intended to limit the invention.

[0041] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of this invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0042] like Figure 1 and Figure 2 As shown in the figure, an airflow detection and obstacle avoidance system based on a rotary-wing UAV according to an embodiment of the present invention includes: a controlled UAV 1, an airflow detection and analysis module 2, and a flight control module 3. The controlled UAV, through the rotation of its wings, draws in air from the upper part of the rotor and compresses the air from the lower part of the rotor, generating lift and causing the UAV to rise into the air. When obstacles such as walls or ceilings appear in the path of the UAV, the presence of the obstacles changes the original airflow path, causing changes in the flow field around the UAV. Therefore, the present invention can determine the location information of obstacles around the UAV by detecting changes in the flow field information around the UAV. The airflow detection and analysis module 2 of the present invention can detect the flow field information around the UAV, analyze and process it to obtain obstacle information, and transmit the obstacle information to the flight control module to control the UAV to complete obstacle avoidance.

[0043] In this invention, such as Figure 1 As shown, the airflow detection and analysis module 2 is located around the body of the controlled drone 1, such as at the bottom or top of the drone, and flies with the drone, detecting the flow field information around the drone body in real time during flight. Taking a quadcopter drone as an example, Figure 1The airflow detection and analysis module 2 is located on the lower part of the controlled drone 1 and is connected to the controlled drone 1 by means of adhesive, screws, or clips. When the controlled drone 1 is in flight, the airflow detection and analysis module 2 detects the airflow field around the drone 1. When there are obstacles around the drone 1, the airflow detection and analysis module 2 detects the change in airflow field and transmits the obstacle information to the flight control module 3 via wired or wireless transmission. Figure 1 The flight control module 3 is located on the upper part of the controlled drone 1. The flight control module 3 replans the path of the controlled drone 1, adjusts the rotational speed ratio of each rotor, adjusts the body attitude and flight path, and achieves obstacle avoidance.

[0044] The airflow detection and analysis module described in this embodiment of the invention includes at least one rigid or flexible guide air pipe. One side of the guide air pipe is connected to the airflow conversion module, and the other side of the guide air pipe is connected to the outside of the UAV body. It is used to detect the air pressure and airflow information of the flow field around the UAV body. The number of guide air pipes is determined according to the accuracy of the detected obstacles.

[0045] Specifically, such as Figure 2 As shown, the airflow detection and analysis module includes: an airflow conversion module 202, a guide air tube 201 connected to the airflow conversion module 202, a biomimetic bidirectional airflow pressure sensor 203 disposed on the airflow conversion module 202, and a signal processing and analysis circuit 204 connected to the biomimetic bidirectional airflow pressure sensor 203.

[0046] Airflow information from around the aircraft is introduced into the airflow conversion module 202 via the guide air pipe 201. The airflow conversion module 202 contains an air passage that introduces external airflow information into the air chamber located at the bionic bidirectional airflow pressure sensor 203. The air chambers of the bionic bidirectional airflow pressure sensor 203 are sealed with sealing rings, both between the air chambers and between the air chamber and the air passage, to prevent interference from external gas information. The bionic bidirectional airflow pressure sensor 203 reacts to the introduced airflow information. When the aircraft encounters an obstacle in its flight direction, the airflow at the corresponding location experiences a decrease in pressure and vibration. This change in airflow causes deformation of the sensitive structure of the bionic bidirectional airflow pressure sensor 203, resulting in a change in the output signal of the bionic bidirectional airflow pressure sensor 203. The signal from the biomimetic bidirectional airflow pressure sensor 203 is led out to the signal processing and analysis circuit 204. The signal processing and analysis circuit 204 performs filtering, amplification and other processing on the sensor signal. When the airflow information of a certain sensor in the analysis circuit suddenly changes, the signal processing and analysis circuit 204 analyzes the signal change, obtains the corresponding position between the obstacle and the aircraft, and transmits the position information of the obstacle to the flight control module 3.

[0047] The function of the guide tube 201 is to introduce airflow information from a specific location on the UAV body into the air cavity where the biomimetic bidirectional airflow pressure sensor 203 is located.

[0048] The guide tube 201 can be made of either rigid or flexible material, but it must be ensured that no blockage occurs during bending.

[0049] like Figure 2 As shown, the guide air duct 201 has an opening at its outer end facing the controlled UAV 1. The opening is located at a point where airflow changes significantly when the rotorcraft approaches an obstacle. The opening direction of the guide air duct can be selected according to the detection requirements, and the opening direction can be combined, such as in the calm wind zone between the rotors. The opening direction of the guide air duct 201 can be selected, such as facing the outer side of the controlled UAV 1 and / or facing the upper part of the body. The opening direction of the guide air duct 201 can be combined. Different combinations of opening directions are beneficial for the UAV to detect obstacles in specific directions. For example, changing the opening direction of the guide air ducts corresponding to each biomimetic bidirectional airflow and pressure sensor to face upwards and downwards can improve the detection sensitivity of obstacles above and below the UAV. The guide air duct 201 is tightly connected to the airflow conversion module 202, which can be achieved by adhesive, bayonet, or screw fastening.

[0050] The airflow detection and analysis module 2 can be combined in various ways, such as sandwich type, drawer type, integrated type, etc. In the figure, the airflow detection and analysis module 2 uses an upper and lower cover plate and a sandwich design. The airflow conversion module of this invention includes a cover plate, and the cover plate contains air channels. The number of air channels is consistent with the number of guide tubes. The air channels transmit the airflow information from the guide tubes to the biomimetic bidirectional airflow pressure sensor, and the air channels form an angle with each other. The cover plate contains the biomimetic bidirectional airflow pressure sensor and a signal processing and analysis circuit. The cover plate seals the airflow information to the location of the biomimetic bidirectional airflow pressure sensor through a sealing ring. That is, the airflow conversion module 202 includes an upper cover plate and a lower cover plate, and the biomimetic bidirectional airflow pressure sensor 203 and the signal processing and analysis circuit 204 are disposed between the upper cover plate and the lower cover plate. The upper cover plate and the lower cover plate are combined by screw fastening. The biomimetic bidirectional airflow pressure sensor 203 is soldered to the circuit board where the signal processing and analysis circuit 204 is located. The circuit board has holes to facilitate the passage of airflow from the lower part.

[0051] The airflow conversion module 202 contains an air guiding channel between the upper and lower cover plates for transmitting airflow information to the location of the biomimetic bidirectional airflow pressure sensor 203. The upper and lower cover plates of the airflow conversion module 202 have cavities near the biomimetic bidirectional airflow pressure sensor 203.

[0052] In this embodiment of the invention, multiple biomimetic bidirectional airflow and pressure sensors 203 are provided. Each biomimetic bidirectional airflow and pressure sensor 203 is connected to and detects the airflow information of at least one airway. The multiple biomimetic bidirectional airflow and pressure sensors cooperate with each other to obtain the encoding of complex obstacles around the UAV body, enabling the detection of multiple obstacles. In this embodiment, airflow information at 180-degree intervals between the airflow detection and analysis module is detected by one biomimetic bidirectional airflow and pressure sensor. That is, the top and bottom, left and right, and front and back of the airflow detection and analysis module are detected by three biomimetic bidirectional airflow and pressure sensors 203, with the detected positions forming a 180-degree angle with the line connecting the airflow detection and analysis module. Airflow information from other airways at different angles can also be detected, such as the detected position forming a 90-degree angle with the line connecting the airflow detection and analysis module. However, to avoid duplicate detection information, the angle between the detected position and the line connecting the airflow detection and analysis module should be greater than or equal to 45 degrees.

[0053] In this embodiment of the invention, the biomimetic bidirectional airflow pressure sensor 203 can detect information from multiple air passages. The multiple biomimetic bidirectional airflow pressure sensors 203 cooperate to realize sensor coding of complex obstacles around the UAV body.

[0054] The airflow detection and analysis module 2 includes at least one airway and at least one biomimetic bidirectional airflow and pressure sensor 203.

[0055] In this embodiment of the invention, the biomimetic bidirectional airflow and pressure sensor 203 array employs different encoding formats to achieve the detection of multiple obstacles. For example... Figure 3 As shown in the example, one of the biomimetic bidirectional airflow pressure sensors 203 is defined as follows: Sensor A detects the airflow in front of and behind the drone, Sensor B detects the airflow to the left and right of the drone, and Sensor C detects the airflow up and down of the drone. The signal when the sensor does not detect an obstacle is defined as 0; a sensitive signal for an obstacle detected in the forward direction is defined as +1; and a sensitive signal for an obstacle detected in the reverse direction is defined as -1. Therefore, this embodiment of the invention can locate obstacles based on the output signals of the sensor arrays A, B, and C. For example, in the airflow detection and obstacle avoidance system based on a rotary-wing drone in this embodiment of the invention, when the drone is flying normally and there are no obstacles around, the output signals of the sensor arrays A, B, and C are: 0, 0, 0. When only an obstacle (such as a wall) appears in front of the drone, the output signals of the sensor arrays A, B, and C are: +1, 0, 0. When an obstacle (such as a corner) appears to the right rear of the drone, the output signals of the sensor arrays A, B, and C are: -1, -1, +1. Therefore, this embodiment of the invention can detect multiple obstacles based on the output signals of the sensor arrays. Increasing the number of sensors allows for a smaller selectable airway angle, enabling more precise obstacle location detection. For example... Figure 3As shown, five biomimetic bidirectional airflow and pressure sensors 203 are used to detect obstacles in five axial directions: sensors A, B, C, D, and E detect the directions of front and back, left and right, right front and left rear, left front and right rear, and up and down, respectively. Figure 3 As shown in the left figure, when an obstacle appears in front of the right side of the drone, the output coded signal of the sensor array is: 0, 0, +1, 0, 0.

[0056] Furthermore, in embodiments of the present invention, if there are limitations in sensor performance or airway position, a sensor redundancy design can be employed to achieve detection in a specific direction. For example... Figure 3 As shown in the right figure, when a sensor can detect bidirectional airflow but cannot distinguish the airflow direction due to performance limitations, a redundant sensor design is used to detect obstacles in a specific direction. For example, four bidirectional airflow sensors a, b, c, and d, which cannot sense airflow direction, are used to detect obstacles in the front-back, left-right, and up-down directions. Sensors a, b, and c are connected to the front-back, left-right, and up-down airflows respectively through air ducts and air channels. Sensor d is a redundant design, connected to the front, right, and up-down airflows through air ducts and air channels. Due to sensor performance limitations, it cannot sense airflow direction. Therefore, this invention encodes the state where the sensor detects an input change as 1 and the state where it does not detect an input change as 0. Thus, when an obstacle appears in front of the drone, the output signal encoding result of the sensor array is: 1, 0, 0, 1. When an obstacle appears behind the drone, the output signal encoding result of the sensor array is: 1, 0, 0, 0. In this way, in this embodiment of the invention, when limited by sensor performance or air channel position, the detection of obstacles in a specific direction can be achieved through sensor redundancy design, improving the detection accuracy.

[0057] In one embodiment, an airflow detection and obstacle avoidance system based on a rotary-wing unmanned aerial vehicle (UAV) according to an embodiment of the present invention, such as... Figure 4 As shown, the biomimetic bidirectional airflow sensor 203 includes: a sensor base 2032, a cross beam structure 2031 disposed in the middle of the sensor base 2032, a cross beam center 2033 disposed at the intersection of the cross beam structure 2031, a biomimetic slit structure 2034 disposed on one side of the cross beam center 2033, a resistor 2035 surrounding the biomimetic slit structure 2034, and a circuit 2036 connected to the resistor.

[0058] Figure 4The diagram shows a schematic of a biomimetic bidirectional airflow sensor 203. A crossbeam structure 2031 and a center 2033 are included at the center of the sensor substrate 2032. The center 2033 is an enlarged area larger than the center area of ​​the crossbeam structure 2031, increasing the projected area of ​​the structure under the flow field. When airflow passes over the crossbeam, it manifests as pressure applied to the surface of the crossbeam. The projected area of ​​the enlarged region at the center 2033 increases the force generated by the airflow under the same pressure. Therefore, by setting the center 2033 of the crossbeam in the biomimetic bidirectional airflow sensor 203 as the center of the enlarged region, the biomimetic bidirectional airflow sensor 203 can respond to minute changes in airflow. The crossbeam structure 2031 includes a biomimetic slot structure 2034. The parameters of the biomimetic slot structure 2034 are designed according to the patent "CN201811643516.2 A biomimetic microcantilever beam structure, its manufacturing method and piezoresistive sensor". The function of the biomimetic slot structure 2034 is the same as that of the biomimetic slot structure in the patent "CN201811643516.2 A biomimetic microcantilever beam structure, its manufacturing method and piezoresistive sensor". The introduction of the biomimetic slot structure 2034 concentrates the stress during structural deformation around the biomimetic slot structure 2034. The resistor 2035 surrounds the biomimetic slot structure 2034, which can more sensitively reflect the deformation of the structure under the flow field. The resistors 2035 are interconnected through circuit 2036 to form a Wheatstone bridge. The biomimetic bidirectional airflow sensor 203 has the same projected area under both forward airflow (flowing through the sensor from top to bottom) and reverse airflow (flowing through the sensor from bottom to top), thus it can respond to both types of airflow. When forward airflow passes through, the resistor bends downward, increasing its resistance; when reverse airflow passes through, the resistor bends upward, decreasing its resistance. Therefore, the direction of airflow can be determined by the output of the bridge circuit on the sensor. When the drone approaches an obstacle, the external airflow changes, causing the biomimetic bidirectional airflow sensor 203 to suddenly deform, which is reflected in its output signal.

[0059] As can be seen from the above, the biomimetic bidirectional airflow pressure sensor of the present invention is a cross beam with an enlarged center and a biomimetic slit structure, fabricated using MEMS technology. The enlarged center position of the cross beam increases the response area of ​​the structure under the flow field, enabling the structure to respond to small changes in airflow. The biomimetic cross beam structure has the same projected area under both forward and reverse airflow, and responds to both forward and reverse airflow.

[0060] In this embodiment of the invention, the biomimetic seam structure 2034 is located at the position of maximum stress outside the expanded area of ​​the cross beam center 2033 of the cross beam structure 2031.

[0061] In this embodiment of the invention, the biomimetic seam structure 2034 is a seam that penetrates the beam structure, and the seam can be straight or curved. The biomimetic seam structure 2034 includes at least one seam.

[0062] The biomimetic bidirectional airflow and pressure sensor is placed on the circuit board of the signal processing and analysis circuit. The sensor's signal is led out to the analysis and processing module, which outputs the processing result to the flight control module. The flight control module then controls the UAV's flight status using the signal from the flight control module.

[0063] In this embodiment of the invention, the force experienced by the biomimetic bidirectional airflow sensor 203 when subjected to a forward airflow is as follows: Figure 5 As shown. The dimensional parameters of the biomimetic bidirectional airflow sensor 203 are in Figure 5 The following is marked. A separate analysis is performed on the beam containing one of the resistors, 2035. When airflow passes over the bidirectional airflow sensor 203, it can be equivalent to three forces applied to the beam: the stress at the expansion center under the flow field, which is averaged across the four beams, with each beam bearing F1; the bending moment M1 at the contact point between the beam and the central block due to the deformation of the expansion center under the flow field; and the pressure q applied to the beam due to the airflow pressure. The bending moment at a point x away from the fixed end on the beam can be calculated using Formula 1:

[0064]

[0065] Where l is the length of the cross beam, x is the distance from the fixed end, w is the width of the cross beam, and the force F1 borne by each beam can be calculated by formula 2:

[0066]

[0067] Where h is the dimension of the enlarged center, and the bending angle at a point on the beam at a distance x from the fixed end can be obtained by integrating the bending moment:

[0068]

[0069] E b It is the elastic modulus of the beam structure, C is the integration constant, and I is the elastic modulus of the beam structure. bz This is the moment of inertia of the beam along the z-axis. It can be obtained from Equation 4:

[0070]

[0071] Where t is the thickness of the beam, and W is the deflection of the beam. l This can be obtained by integrating the degree of bending of the beam:

[0072]

[0073] D is a constant, and the values ​​of C and D can be obtained by introducing boundary conditions. When the value of x is 0, that is, when the selected point is located at the fixed end, the bending angle and deflection are 0. Substituting this boundary condition, the bending moment M1 generated at the contact position between the beam and the center block can be obtained, as shown in the following formula:

[0074]

[0075] Substituting the bending moment M1 into the deflection formula, we can obtain the bending moment calculation formula for the beam structure:

[0076]

[0077] The longitudinal stress on the beam can be obtained by the following formula:

[0078]

[0079] Where W is the section modulus in the Z direction, which can be calculated using the following formula:

[0080]

[0081] Therefore, the longitudinal stress can be calculated using the following formula:

[0082]

[0083] As can be seen from the above, this invention discloses an airflow detection and obstacle avoidance system based on a rotary-wing UAV. The system includes a controlled UAV, an airflow detection and analysis module, and a flight control module. The airflow detection and analysis module comprises a guide tube, an airflow conversion module, a biomimetic bidirectional airflow pressure sensor, and a signal processing and analysis circuit. During flight, the flow field information around the UAV is guided to the biomimetic bidirectional airflow pressure sensor via the guide tube and the airflow conversion module. The biomimetic bidirectional airflow pressure sensor detects airflow information in at least one direction and converts the flow field information into an electrical signal, which is then output to the signal processing and analysis circuit. The signal processing and analysis circuit processes and analyzes the signals collected by the sensor to determine the distribution of obstacles around the UAV and transmits the analysis results to the UAV flight control module. The UAV flight control module plans the UAV's flight path and controls the rotor state to complete obstacle avoidance. The biomimetic bidirectional airflow sensor is a crossbeam with an enlarged center and a biomimetic slit structure, fabricated using MEMS technology. The enlarged center increases the sensor's projected area in the flow field, enabling the structure to respond to minute changes in airflow. The biomimetic slit structure is located on the crossbeam and surrounded by a piezoresistive sensing structure. The stress generated by the deformation of the crossbeam is concentrated at the piezoresistive positions around the biomimetic slit structure, improving the sensor's sensitivity. The obstacle avoidance system detects obstacles by using flow field information around the drone's body, enabling the system to quickly and sensitively detect surrounding obstacles, even in scenarios where traditional optical detection is limited.

[0084] Based on the airflow detection and obstacle avoidance system based on a rotary-wing UAV as described above, this invention also provides an obstacle avoidance detection method for the airflow detection and obstacle avoidance system based on a rotary-wing UAV. The obstacle avoidance control method for the airflow detection and obstacle avoidance system based on a rotary-wing UAV in this embodiment includes the following steps:

[0085] The control unit is set up around the airflow detection and analysis module of the controlled drone body to detect the airflow field change data around the controlled drone body, analyze the detected airflow field change data, determine whether there is obstacle information around the controlled drone body, and determine the location information of the obstacle around the drone body.

[0086] The flight control module, located on the body of the controlled UAV, replans the path of the controlled UAV based on the location information of obstacles around the body sent by the airflow detection and analysis module. It controls the controlled UAV to adjust the speed ratio of each rotor, adjust the body attitude and flight path to avoid obstacles.

[0087] Specifically, for example, such as Figure 3As shown, one of the biomimetic bidirectional airflow pressure sensors 203 is defined as follows: Sensor A detects the airflow in front of and behind the drone, Sensor B detects the airflow to the left and right of the drone, and Sensor C detects the airflow up and down of the drone. The signal when the sensor does not detect an obstacle is defined as 0; a sensitive signal for an obstacle detected in the forward direction is defined as +1; and a sensitive signal for an obstacle detected in the reverse direction is defined as -1. Therefore, this embodiment of the invention can locate obstacles based on the output signals of the sensor arrays A, B, and C. For example, in the airflow detection and obstacle avoidance system based on a rotary-wing drone in this embodiment of the invention, when the drone is flying normally and there are no obstacles around, the output signals of the sensor arrays A, B, and C are: 0, 0, 0. When only an obstacle (such as a wall) appears in front of the drone, the output signals of the sensor arrays A, B, and C are: +1, 0, 0. When an obstacle (such as a corner) appears to the right rear of the drone, the output signals of the sensor arrays A, B, and C are: -1, -1, +1. Therefore, this embodiment of the invention can detect multiple obstacles based on the output signals of the sensor arrays. Increasing the number of sensors allows for a smaller selectable airway angle, enabling more precise obstacle location detection. For example... Figure 3 As shown, five biomimetic bidirectional airflow and pressure sensors 203 are used to detect obstacles in five axial directions: sensors A, B, C, D, and E detect the directions of front and back, left and right, right front and left rear, left front and right rear, and up and down, respectively. Figure 3 As shown in the left figure, when an obstacle appears in front of the right side of the drone, the output coded signal of the sensor array is: 0, 0, 1, 0, 0.

[0088] Then, the flight control module, based on the location information of obstacles around the aircraft sent by the airflow detection and analysis module, replans the path of the controlled drone, adjusts the rotational speed ratio of each rotor, and adjusts the aircraft attitude and flight path to avoid obstacles.

[0089] In summary, this invention provides an airflow detection and obstacle avoidance system and method based on a rotary-wing UAV. During UAV flight, obstacles around the aircraft affect the flow field. The flow field information is transmitted to a biomimetic bidirectional airflow and pressure sensor via the guiding air duct and airflow conversion module of the UAV-based airflow detection and obstacle avoidance system. This biomimetic bidirectional airflow and pressure sensor includes an enlarged central structure and a biomimetic slit structure, capable of responding to minute changes in bidirectional airflow. The sensor detects the flow field information around the UAV, and the position of obstacles around the UAV is obtained through a signal processing and analysis module. The flight control module then controls the UAV's flight. By using a flow field approach to detect obstacle information around the UAV, and with on-board signal processing, complex signal transmission processes are eliminated, enabling rapid signal processing and improving signal detection and judgment speed. This gives the UAV obstacle avoidance system the ability to quickly detect flow field information. The flow field-based obstacle detection method allows the system to be applied in scenarios where optical detection is limited.

[0090] It should be understood that the application of the present invention is not limited to the examples above. Those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A rotorcraft-based airflow detection obstacle avoidance system, comprising: include: The controlled drone's airflow detection and analysis module is set around the drone's body to detect changes in the airflow field around the drone's body, analyze the detected airflow field changes, determine whether there are obstacles around the drone's body, and determine the location of the obstacles. A flight control module is installed on the body of the controlled UAV and connected to the airflow detection and analysis module. The flight control module is used to replan the path of the controlled UAV based on the location information of obstacles around the body sent by the airflow detection and analysis module, and control the controlled UAV to adjust the speed ratio of each rotor, adjust the body attitude and flight path to avoid obstacles. The airflow detection and analysis module includes: Airflow conversion module; A guide tube connected to the airflow conversion module is used to introduce airflow; A biomimetic bidirectional airflow pressure sensor is mounted on the airflow conversion module, and a signal processing and analysis circuit is connected to the biomimetic bidirectional airflow pressure sensor. The guiding air tube is used to introduce airflow information from a specific location on the UAV body into the air chamber where the biomimetic bidirectional airflow and pressure sensor is located on the airflow conversion module; The airflow conversion module contains an air passage that introduces external airflow information into the air cavity where the biomimetic bidirectional airflow pressure sensor is located. The airflow conversion module and the bionic bidirectional airflow pressure sensor are sealed with sealing rings between the air chambers and between the air chambers and the air passages. The bionic bidirectional airflow pressure sensor is used to respond to the introduced airflow information. When the aircraft encounters an obstacle in the flight direction, the airflow at the corresponding position changes. The change in airflow causes the sensitive structure of the bionic bidirectional airflow pressure sensor to deform and outputs the change signal to the signal processing and analysis circuit. The signal processing and analysis circuit is used to filter and amplify the changing signals output by the biomimetic bidirectional airflow pressure sensor; and when the signal processing and analysis circuit analyzes that the airflow information of a certain biomimetic bidirectional airflow pressure sensor suddenly changes, it analyzes the signal change to obtain the corresponding position between the obstacle and the aircraft, and transmits the position information of the obstacle to the flight control module. The biomimetic bidirectional airflow pressure sensor includes: a sensor base, a cross beam structure disposed in the middle of the sensor base, a cross beam center disposed at the intersection of the cross beam structure, a biomimetic slit structure disposed on one side of the cross beam center, a resistor connected to the biomimetic slit structure, and a circuit connected to the resistor. The center of the cross beam is set as an enlarged area that is larger than the center area of ​​the cross beam structure; The biomimetic seam structure is located at the position of maximum stress outside the expanded area at the center of the cross beam structure. 2.The rotor-based UAV air flow detection obstacle avoidance system of claim 1, wherein, The airflow detection and analysis module is installed on the lower part of the controlled drone body by means of pasting, screw fastening or clipping. 3.The rotor-based UAV air flow detection obstacle avoidance system of claim 1, wherein, The guide tube has an opening at one end facing the outside of the body, and the opening is located on the outside of the controlled UAV body and / or facing the upper part of the body. 4.The rotor-based UAV air flow detection obstacle avoidance system of claim 1, wherein, The air guide tube is fixed to the airflow conversion module by adhesive, bayonet, or spiral fastening. 5.The rotor-based UAV air flow detection obstacle avoidance system of claim 2, wherein, The airflow conversion module comprises an upper cover plate and a lower cover plate, the bionic bidirectional airflow pressure sensor and the signal processing and analysis circuit are arranged between the upper cover plate and the lower cover plate; the upper cover plate and the lower cover plate are combined by screw fastening; the bionic bidirectional airflow pressure sensor is welded on the circuit board where the signal processing and analysis circuit is arranged; The interior between the upper cover plate and the lower cover plate of the airflow conversion module comprises a gas guide channel for guiding airflow information to the position where the bionic bidirectional airflow pressure sensor is arranged, and the interior of the upper cover plate and the lower cover plate of the airflow conversion module is provided with a cavity near the position of the bionic bidirectional airflow pressure sensor.

6. The rotor based unmanned aerial vehicle based air flow detection obstacle avoidance system of claim 1, wherein, The airflow detection and analysis module comprises at least one gas channel and at least one bionic bidirectional airflow pressure sensor. The airflow information at positions 45 degrees or above each other of the airflow detection and analysis module is detected by one bionic bidirectional airflow pressure sensor.

7. The rotor based unmanned aerial vehicle based air flow detection obstacle avoidance system of claim 1, wherein, The bionic bidirectional airflow pressure sensor can detect information of multiple gas channels, and multiple bionic bidirectional airflow pressure sensors are matched to form a bionic bidirectional airflow pressure sensor array for realizing sensor coding of complex obstacles around the unmanned aerial vehicle body. The bionic bidirectional airflow pressure sensor array adopts different coding forms for realizing detection of multiple obstacles.

8. The obstacle avoidance control method of the rotor-based unmanned aerial vehicle based airflow detection obstacle avoidance system according to any one of claims 1-7, characterized in that, The method comprises the steps of: controlling the airflow detection and analysis module arranged around the controlled unmanned aerial vehicle body to detect airflow flow field change data around the controlled unmanned aerial vehicle body, analyzing the detected airflow flow field change data, judging whether there is obstacle information around the controlled unmanned aerial vehicle body, and judging position information of obstacles around the body; controlling the flight control module arranged on the controlled unmanned aerial vehicle body to re-plan the path of the controlled unmanned aerial vehicle according to the position information of obstacles around the body sent by the airflow detection and analysis module, control the controlled unmanned aerial vehicle to adjust the rotation speed ratio of each rotor, adjust the body attitude and flight path, and avoid obstacles.

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