Gas source autonomous searching method based on two-stage path

Abstract

The invention provides a gas source autonomous searching method based on a two-stage path, and relates to the field of mobile robot autonomous navigation, and the method comprises the steps: carrying out the smoky rain boundary exploration through an Archimedes spiral path, and guiding a robot to enter smoky rain; tracking the gas leakage source against wind in the smoky rain based on a zigzag path until coarse positioning of the gas leakage source is completed, wherein the robot is not in the smoky rain at the moment; on the basis of the coarse positioning result, the robot is guided to return to the smoky rain again through an inverted zigzag path, accurate positioning of the gas leakage source is completed through an inner spiral path or a pendulum spiral path, accurate positioning of the harmful gas source can be achieved in the actual dynamic wind field environment through the single mobile robot provided with the gas sensor, and accurate positioning of the harmful gas source is achieved. The method is especially suitable for pollution source tracking in open spaces such as refuse landfills and industrial parks.

Description

Technical Field

[0001] This invention relates to the field of autonomous navigation technology for mobile robots, and in particular to a method for autonomously searching for gas sources based on a two-stage path. Background Technology

[0002] With the acceleration of industrialization and urbanization, the emission of harmful gases from environmental pollution sources such as industrial parks and municipal sewage treatment plants is becoming increasingly serious, posing a significant threat to public health. Locating the source of harmful gas leaks is a crucial step in gas pollution monitoring. However, gas diffusion is influenced by multiple factors, including gas source characteristics, emission methods, and meteorological conditions, making tracking difficult, especially in dynamic and unknown environments. This presents a significant challenge to autonomous mobile robot systems. Existing model-based methods often rely on prior knowledge or are computationally complex, limiting their adaptability to real-world scenarios and suffering from problems such as large positioning errors. Summary of the Invention

[0003] To address the aforementioned problems, this invention provides a gas source autonomous search method based on a two-stage path. This invention offers a model-independent, highly accurate, and widely applicable gas source tracing algorithm, which is of great significance for gas pollution monitoring and environmental protection. Specifically, it includes:

[0004] A gas source autonomous search method based on a two-stage path includes:

[0005] S1. Place the robot in the target environment and output the robot's dynamic position information in real time through coordinate iteration, wherein the robot monitors the gas concentration in real time;

[0006] S2. Explore the boundary of the misty rain using the Archimedes spiral path and guide the robot into the misty rain;

[0007] S3. Based on a zigzag path, the robot tracks the gas leak source against the wind in the misty rain until the coarse location of the gas leak source is completed. At this time, the robot is not in the misty rain.

[0008] S4. Based on the coarse positioning results, guide the robot back to the misty rain through a reverse zigzag path, and complete the precise positioning of the gas leak source through an inner spiral path or a pendulum spiral path.

[0009] Optionally, the dynamic equation for outputting the robot's dynamic position information in real time through coordinate iteration in S1 is Equation (1):

[0010] P k+1 =P k +u k (1)

[0011] Among them, P k =[Pkx P ky ] T is the current position coordinate of the robot, k is the iteration number, P k+1 is the next coordinate position of the robot, u k is the system input;

[0012] The robot supports determining the target position to be reached next according to the gas concentration value C(P k ) at the current position.

[0013] Optionally, the smoke-rain boundary exploration and guiding the robot to enter the smoke-rain by the over-Archimedes spiral path in S2 comprises:

[0014] S201, guiding the robot to spiral motion based on the polar coordinate equation of the Archimedes spiral path combined with the dynamic equation of the dynamic position information of the robot;

[0015] S202, when the concentration detected by the robot is greater than the threshold τ, it is determined that the current position is the smoke-rain boundary, the position of the smoke-rain boundary is P s(0) , and the robot stops the spiral motion;

[0016] S203, guiding the robot to enter the smoke-rain based on the dynamic equation of the dynamic position information of the robot.

[0017] Optionally, the polar coordinate equation of the Archimedes spiral path in S201 is formula (2) and formula (3):

[0018] P kx = bΘcosΘ + P 0x ; (2)

[0019] P ky = bΘsinΘ + P 0y ; (3)

[0020] Wherein, b is the rotation interval coefficient and b>0, Θ is the cumulative rotation angle and Θ=kΘ0; Θ0 is the angle increment.

[0021] Optionally, the zigzag path-based upwind tracking of the gas leakage source in the smoke-rain until the coarse positioning of the gas leakage source is completed in S3 comprises:

[0022] S301, driving the robot to switch to zigzag path motion;

[0023] Wherein, the walking distance of each time of the zigzag path motion is d k ;

[0024] Wherein, the counterclockwise turning angle of the robot when switching any two adjacent line segment paths is θ k ;

[0025] S302, when the maximum concentration in the current line segment of the robot does not exceed q times the previous segment, driving the robot to stop tracking the gas leakage source against the wind, the robot completes the coarse positioning of the gas leakage source;

[0026] Wherein, 0

[0027] Optionally, the driving robot of S301 switches to zigzag path movement includes:

[0028] If C(P k )≥τ:

[0029] Then drive the robot to move forward by step d1;

[0030] If C(P k )<τ, and the cumulative step length of the path in the current line segment does not reach the threshold, it is determined that the robot is currently in the smoke rain:

[0031] Then drive the robot to move forward by step d2;

[0032] If C(P k )<τ, and the cumulative step length of the path in the current line segment reaches the threshold d s , it is determined that the robot is not currently in the smoke rain:

[0033] Then drive the robot to move back along the original path to the smoke rain by step d3, and drive the robot to rotate in the opposite direction by θ k .

[0034] Optionally, d k and θ k in S301 and the relationship between system input u k satisfy formula (4):

[0035]

[0036] Wherein, the reference wind direction is defined as the positive direction of x axis, and the rotation angle satisfies formula (5):

[0037]

[0038] Wherein, the subscript n of s(n) represents the index of the rotation point, mod is the remainder symbol, and n is a non-negative integer.

[0039] Optionally, the S4 includes:

[0040] S401, guiding the robot to return to the smoke rain based on a reverse zigzag path, when the current gas concentration > τ, it is judged that the robot returns to the smoke rain;

[0041] S402, driving the robot to continue to move according to the reverse zigzag path until the current time gas concentration < τ and the last time gas concentration > τ, the robot stops moving, and the robot stops at P s(e) ;

[0042] S403, taking P s(e) as the starting point, controlling the robot to search for the gas leakage source based on an inner spiral path or a pendulum spiral path to obtain the accurate position of the gas leakage source.

[0043] Optionally, the S401 of guiding the robot to return to the smoke rain based on a reverse zigzag path comprises:

[0044] The corner constraint condition of the reverse zigzag path is formula (6):

[0045]

[0046] Wherein, s(f) is the starting index of the reverse zigzag; s(e) is the termination index of the reverse zigzag;

[0047] Driving the robot to move according to the step lengths d4, d5 and d6, and the accumulation threshold of each line segment path in the reverse zigzag path is d s ' < d s ;

[0048] Wherein, d4 < (d1, d2, d3); d5 < (d1, d2, d3); d6 < (d1, d2, d3);

[0049] The opening angle of the reverse zigzag path is < the opening angle of the zigzag path.

[0050] Optionally, the S403 of taking P s(e) as the starting point, controlling the robot to search for the gas leakage source based on an inner spiral path or a pendulum spiral path to obtain the accurate position of the gas leakage source comprises:

[0051] When searching for the gas leakage source according to the inner spiral path:

[0052] The inner spiral path trajectory satisfies formula (7):

[0053]

[0054] P s(e)x and P s(e)y are the horizontal and vertical coordinates of the starting point of the inner spiral path respectively;

[0055] r is the polar radius of the spiral line, P h is the midpoint of the previous zigzag fold line, Θ0' is an angle increment smaller than Θ0, r = r0 - b1Θ and r ≥ δ, δ is the threshold of the polar radius of the spiral line, b1 is a constant;

[0056] Φ is the rotation angle of the starting point P s(e) to the target point P h ;

[0057] The stop condition of the inner spiral trajectory is that when r decreases to the threshold δ, the robot stops moving, and the highest gas concentration point on the current spiral segment is the gas leakage source;

[0058] When searching for the gas leakage source along the inner pendulum spiral path:

[0059] P h is the midpoint of the previous zigzag fold line;

[0060] The line segment P s(e) P h is divided into γ segments according to the points P h(1) , P h(2) , P h(γ) ;

[0061] After guiding the robot to reach the point P s(e) from P h in a clockwise spiral, the robot is driven to spiral through the segmented points on the line segment P s(e) P h in an alternating clockwise and counterclockwise manner;

[0062] Wherein, the spiral line segment between two points satisfies formula (8):

[0063]

[0064] Wherein, r(Θ) = b2(Θ i - Θ)a;

[0065] Wherein, a = ±1 is the direction factor, +1 indicates counterclockwise, and -1 indicates clockwise;

[0066] Θ i is the starting angle, Θ i = Θ j + a·r j / b2, r j is the terminal polar radius, and b2 is the expansion coefficient;

[0067] P jx , P jy are the horizontal and vertical coordinates of the end point of each spiral segment, respectively; P ix , P iyThe horizontal and vertical coordinates of the starting point of each helix segment, respectively;

[0068] When the concentration of all points on the current helix segment is less than the threshold τ, the robot is stopped;

[0069] The point with the highest gas concentration on the current helix segment is the gas leakage source.

[0070] Compared with the prior art, the technical scheme has at least the following beneficial effects:

[0071] The present application realizes accurate positioning of harmful gas sources in an actual dynamic wind field environment by a single mobile robot equipped with a gas sensor. The method is particularly suitable for tracking pollution sources in open spaces such as landfills and industrial parks. The movement control of the mobile robot can be completed autonomously by measuring data through its sensors and according to the designed algorithm without relying on a PC control end. The execution process of the method is shown in Figure 1 The method includes sampling gas concentration values by a mobile robot equipped with a sensor, and performing stage one and stage two movement control, respectively. Stage one is a coarse search stage, including smoke rain discovery and smoke rain tracking, and uses an Archimedean spiral trajectory and a zigzag trajectory, respectively. Stage two is a fine search stage, including inverse zigzag return to smoke rain and fine search for the source position using an inner helix / dipper helix path. BRIEF DESCRIPTION OF DRAWINGS

[0072] To more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings needed in the embodiment description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative effort based on these drawings.

[0073] Figure 1 The flowchart of an embodiment of the present application;

[0074] Figure 2 The schematic diagram of the platform of an embodiment of the present application;

[0075] Figure 3 The path trajectory conversion schematic diagram of steps S2 to S3 of an embodiment of the present application;

[0076] Figure 4 The trajectory schematic diagram of two path searches in step S4 of an embodiment of the present application. DETAILED DESCRIPTION

[0077] In order to make the purposes, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions of the embodiments of the present application will be described clearly and completely below with reference to the drawings of the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the described embodiments of the present application, all other embodiments obtained by a person of ordinary skill in the art without any inventive effort fall within the scope of protection of the present application.

[0078] Unless otherwise defined, technical terms or scientific terms used in the present application shall have the common meaning understood by a person of ordinary skill in the art to which the present application belongs. The terms "first", "second" and similar words used in the present application do not represent any order, number or importance, but are only used to distinguish different components. Similarly, the terms "one", "an" or "the" and similar words do not represent a quantity limitation, but represent the existence of at least one. The terms "include" or "contain" and similar words mean that the elements or objects before the words cover the elements or objects listed after the words and their equivalents, and do not exclude other elements or objects. The terms "connect" or "connected" and similar words are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect.

[0079] Zigzag path and spiral path are two simple and efficient traversal modes, which are often used to design bionic algorithms for gas source positioning. Zigzag path can guide the robot to shuttle back and forth between plumes to achieve the effect of upwind tracing. Spiral path can be used not only for plume tracing and fine positioning of the source position, but also for discovering the plume boundary to achieve effective positioning task at any starting point, especially for the rare case that the starting point of the robot is located at the back of the source. By combining the idea of non-convex optimization, the maximum concentration point is output as the predicted position to achieve the purpose of positioning.

[0080] In view of the problems of the prior art, such as dependence on prior knowledge, poor positioning accuracy and poor applicability, the present application provides a gas source autonomous search method based on a two-stage path, the main principle of which is as follows: in the coarse search stage, the spiral path is used to discover the plume and combine the zigzag upwind tracking, and in the fine search stage, the inverse zigzag path is used to re-enter the plume, and then the inner spiral / dip-spiral algorithm is used to achieve accurate positioning of the leakage source.

[0081] The present application can achieve accurate positioning of harmful gas sources in actual dynamic wind field environment by a single mobile robot equipped with a gas sensor, and is especially suitable for tracking pollution sources in open spaces such as landfills and industrial parks.

[0082] The specific scheme is as follows:

[0083] AsFigures 1 to 4 As shown in the figure, a gas source autonomous search method based on a two-stage path includes:

[0084] S1, place the robot in the target environment, output the dynamic position information of the robot in real time through coordinate iteration, wherein the robot monitors the gas concentration in real time;

[0085] S2, explore the smoke and rain boundary through an Archimedean spiral path and guide the robot into the smoke and rain;

[0086] S3, based on a zigzag path, track the gas leakage source against the wind in the smoke and rain until the coarse positioning of the gas leakage source is completed, at which time the robot is not in the smoke and rain;

[0087] S4, based on the result of coarse positioning, guide the robot to return to the smoke and rain through an inverse zigzag path, and complete the precise positioning of the gas leakage source through an inner spiral path or a pendulum spiral path.

[0088] In a specific embodiment, the dynamic equation for outputting the dynamic position information of the robot in real time through coordinate iteration in S1 is formula (1):

[0089] P k+1 =P k +u k ; (1)

[0090] wherein P k =[P kx ,P ky ] T is the current position coordinate of the robot, k is the iteration number, P k+1 is the next coordinate position of the robot, and u k is the system input;

[0091] The robot supports determining the target position to be reached next according to the gas concentration value C(P k ) at the current position.

[0092] In this embodiment, the mobile robot system is composed of a control end, a Wifi or Bluetooth communication module, a positioning module, a mobile robot (equipped with a gas sensor), and the like. The mobile robot calculates the travel path through an algorithm according to the detected gas concentration data, autonomously completes the source search task, and continuously sends and receives the data and the current coordinate position in the process. The control of the mobile robot system is in the form of coordinate iteration of the robot position, and the coordinate iteration term of the robot position is taken as the input of the system. The dynamic of the robot can be represented as the system equation formula (1). The robot will determine the target position to be reached next according to the measurement value C(P k), to determine the target position that needs to be visited next. The autonomous source-seeking process is completed in the order of "measure-move-measure".

[0093] The search method includes a first stage (a coarse search stage) and a second stage (a fine search stage), the first stage includes two steps of smoke discovery and smoke tracking, and the second stage includes two fine search strategies of reverse zigzag and inner spiral / dipper spiral. The smoke discovery is to search the smoke boundary through a path in the form of an Archimedes spiral line, so as to achieve the purpose of entering the smoke.

[0094] In a specific embodiment, the Archimedes spiral path in S2 performs smoke boundary exploration and guides the robot to enter the smoke, and includes:

[0095] S201, based on the polar equation of the Archimedes spiral path and the dynamic equation of the dynamic position information of the robot, guiding the robot to perform spiral motion;

[0096] The polar equation of the Archimedes spiral path is formula (2) and formula (3):

[0097] P kx =bΘcosΘ+P 0x ; (2)

[0098] P ky =bΘsinΘ+P 0y ; (3)

[0099] Wherein, b is the pitch coefficient and b>0, Θ is the cumulative rotation angle and Θ=kΘ0; Θ0 is the angle increment.

[0100] S202, when the concentration detected by the robot is greater than the threshold τ, it is determined that the current position is the smoke boundary, and the position of the smoke boundary is P s(0) , and the robot stops spiral motion;

[0101] S203, based on the dynamic equation of the dynamic position information of the robot, guiding the robot to enter the smoke.

[0102] The smoke tracking is a source tracing process after the smoke is discovered, which is performed by a zigzag method. The motion trajectory is through the walking distance d k and the counterclockwise rotation angle θ k . In a specific embodiment, the S3 of the zigzag path based on the zigzag path in the smoke to track the gas leakage source against the wind until the coarse positioning of the gas leakage source is completed includes:

[0103] S301, driving the robot to switch to zigzag path motion;

[0104] The S301 of driving the robot to switch to zigzag path motion includes:

[0105] If C(P) k )≥τ:

[0106] Then drive the robot to move forward according to step size d1;

[0107] If C(P) k If τ < τ, and the cumulative step length of the path within the current line segment has not reached the threshold, then the robot is currently inside the misty rain area.

[0108] Then the robot will move forward with a step length d2;

[0109] If C(P) k ) < τ, and the cumulative step size of the path within the current line segment reaches the threshold d. s It is determined that the robot is not currently within the misty rain area.

[0110] The robot is then driven to retreat along the original path into the misty rain with a step size d3, and the robot is driven to rotate in the opposite direction by θ. k .

[0111] Wherein, the distance traveled in each step of the zigzag path movement is d. k ;

[0112] The counterclockwise rotation angle θ is the angle at which the robot switches between any two adjacent line segments. k ;

[0113] d in S301 k and θ k With system input u k The relationship satisfies formula (4):

[0114]

[0115] Among them, the reference wind direction is defined. If the x-axis is the positive direction, then the rotation angle satisfies formula (5):

[0116]

[0117] In s(n), the subscript n represents the corner index, mod is the modulo operator, and n is a non-negative integer.

[0118] S302. When the maximum concentration in the current line segment of the robot does not exceed q times that of the upper segment, the robot is driven to stop tracking the gas leak source against the wind, and the robot completes the coarse location of the gas leak source.

[0119] Where 0 < q < 1.

[0120] The main principle of this step is: if the detected concentration C(P) k) < τ, then continue to move with step size d2, and calculate whether the accumulated movement reaches a distance threshold d k ; s If not, it is considered that the robot is still inside the smoke, and once C(P k ) > τ, then continue to move with step size d1, and if the accumulated movement reaches a distance threshold d k , and the concentration continues to satisfy C(P k ) < τ, then reverse by a larger angle θ k , and walk back a large step d3 distance and then return to the smoke, and so on. The stopping condition of the zigzag path is that the maximum concentration on the current zigzag polyline segment does not exceed q times (0 < q < 1) of the maximum concentration of the previous zigzag polyline segment.

[0121] Phase two first adopts an inverse zigzag path to guide the robot to return to the smoke. The control input form is the same as the zigzag, and in a specific embodiment, the result based on coarse positioning in S4 guides the robot to return to the smoke through an inverse zigzag path, and completes the precise positioning of the gas leakage source through an inner spiral path or a pendulum spiral path, which includes:

[0122] S401, guide the robot to return to the smoke based on the inverse zigzag path, when the current gas concentration > τ, then determine that the robot has returned to the smoke;

[0123] The turning angle constraint condition of the inverse zigzag path is formula (6):

[0124]

[0125] Where s(f) is the starting index of the inverse zigzag, and s(e) is the termination index of the inverse zigzag;

[0126] Drive the robot to move according to step sizes d4, d5, and d6, and the accumulation threshold of each line segment path in the inverse zigzag path is d s ' < d s ;

[0127] Where d4 < (d1, d2, d3); d5 < (d1, d2, d3); d6 < (d1, d2, d3);

[0128] The opening angle of the inverse zigzag path is smaller than the opening angle of the zigzag path.

[0129] The principle of this step is that the travel distances d1, d2, d3 are changed to small step sizes d4, d5, d6, and the threshold d s is changed to a small threshold d s ', and the angle adjustment is smaller than the opening angle formed by the previous zigzag. The stopping condition of the inverse zigzag is that C(P kWhen t, it is considered to enter the plume again, if continue to walk in zigzag, and detect just out of the plume, at this time the robot stops at P s(e) point, that is, satisfies (C(P k-1 )≥τ, C(P k )<τ).

[0130] S402, drive the robot to continue to walk along the inverse zigzag path until the current time gas concentration <τ and the last time gas concentration >τ, the robot stops moving, the robot stops at P s(e) point;

[0131] S403, take P s(e) point as the starting point, control the robot to search for the gas leakage source based on the inner spiral path or the pendulum spiral path, and obtain the accurate position of the gas leakage source.

[0132] (1) When searching for the gas leakage source along the inner spiral path:

[0133] The inner spiral path trajectory satisfies formula (7):

[0134]

[0135] P s(e)x and P s(e)y are the horizontal and vertical coordinates of the starting point of the inner spiral path;

[0136] r is the polar radius of the spiral line, P h is the midpoint of the previous inverse zigzag polyline, Θ0' is an angle increment smaller than Θ0, r=r0-b1Θ and r≥δ, δ is the polar radius threshold of the spiral line, b1 is a constant;

[0137] Φ is the rotation angle from the starting point P s(e) to the target point P h ,

[0138] The stop condition of the inner spiral trajectory is that when r is reduced to the threshold value δ, the robot stops moving, and the highest gas concentration point on the current spiral segment is the gas leakage source;

[0139] (2) When searching for the gas leakage source along the inner pendulum spiral path:

[0140] P h is the midpoint of the previous inverse zigzag polyline;

[0141] The line segment P s(e) P h is divided into γ segments according to the points P h(1) , P h(2) , P h(γ) ;

[0142] The robot is guided to perform a clockwise spiral from P s(e) to point P h After that, the robot is driven to perform a spiral through the segment points on line segment P s(e) P h in an alternating clockwise and counterclockwise manner;

[0143] For example: the robot is guided to perform P s(e) → P h → P h(1) → P h(γ) → P h(2) → P h(γ-1) … in an alternating clockwise / counterclockwise spiral.

[0144] Wherein, the spiral line segment between two points satisfies formula (8):

[0145]

[0146] Wherein, r(Θ)=b2(Θ i -Θ)a;

[0147] Wherein, a=±1 is a direction factor, +1 represents counterclockwise, and -1 represents clockwise;

[0148] Θ i is a starting angle, Θ i =Θ j +a·r j / b2, r j is a terminal polar radius, and b2 is an expansion coefficient;

[0149] P jx , P jy are the horizontal and vertical coordinates of the end point of each spiral segment, respectively; P ix , P iy are the horizontal and vertical coordinates of the starting point of each spiral segment, respectively;

[0150] When the concentration of all points on the current spiral segment is less than the threshold τ, the robot stops;

[0151] The point with the highest gas concentration on the current spiral segment is the gas leakage source.

[0152] In a specific embodiment, for an open scene of (40×20)m, the following parameters can be used to implement the method.

[0153] In the coarse search stage, the spiral path parameters are set as: b=0.2, Θ0=0.01π,

[0154] The threshold τ for entering the plume needs to be determined according to the specific detection material and sensor model.

[0155] For zigzag phase (for example, entering the plume from the upper boundary, as shown in Figure 3 ):

[0156] The angles are: θ s(0) = 245°, θ s(1) = 230°, θ s(2) = 130°, respectively;

[0157] The steps are: d1 = 0.5m, d2 = 0.2m, d3 = 4m, respectively;

[0158] The stop condition threshold is: ∈ = 0.6;

[0159] In the fine search phase, for the reverse zigzag phase, the angles are:

[0160] θ s(f) = 230°, θ s(f+1) = 190°, θ s(f+2) = 170°, respectively;

[0161] The steps are: d4 = 0.1m, d5 = 0.1m, d6 = 2m, respectively;

[0162] The stop condition threshold is: ∈' = 0.3;

[0163] In the inner spiral and pendulum spiral, the spiral parameters are set as: b1 = 0.02, b2 = log(i+1),

[0164] Θ'0 = 0.005π;

[0165] Wherein, i is the number of line segment labels as shown in the appendix Figure 4 .

[0166] The present application realizes accurate positioning of harmful gas sources in actual dynamic wind field environment by a single mobile robot equipped with a gas sensor, and the method is especially suitable for pollution source tracking in open spaces such as landfills and industrial parks. The movement control of the mobile robot can be completed autonomously by the data measured by its sensor and according to the designed algorithm without relying on the PC control end. The execution process of the method is shown in Figure 1 , which includes: using the mobile robot equipped with the sensor to sample the gas concentration value, and performing movement control in phase one and phase two, respectively; phase one is a coarse search phase, including smoke rain discovery and smoke rain tracking, and respectively adopting an Archimedes spiral trajectory and a zigzag trajectory; phase two is a fine search phase, including reverse zigzag returning to the smoke rain and fine searching for the source position by adopting an inner spiral / pendulum spiral path.

[0167] The following points need to be explained:

[0168] (1) The drawings of the embodiments of the present application only relate to the structures involved in the embodiments of the present application, and other structures can be referred to the general design.

[0169] (2) In the drawings used to describe the embodiments of the present application, the thickness of a layer or region is exaggerated or reduced for clarity, i.e., the drawings are not drawn according to the actual scale. It can be understood that when an element such as a layer, film, region or substrate is referred to as being "on" or "under" another element, it can be "directly" on or under the other element or there can be an intermediate element.

[0170] (3) In the case of no conflict, the embodiments of the present application and the features in the embodiments can be combined with each other to obtain new embodiments.

[0171] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto, and the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A gas source autonomous search method based on a two-stage path, characterized in that, include: S1. Place the robot in the target environment and output the robot's dynamic position information in real time through coordinate iteration, wherein the robot monitors the gas concentration in real time; S2. Explore the boundary of the misty rain using the Archimedes spiral path and guide the robot into the misty rain; S3. Based on a zigzag path, the robot tracks the gas leak source against the wind in the misty rain until the coarse location of the gas leak source is completed. At this time, the robot is not in the misty rain. S4. Based on the coarse positioning results, guide the robot back to the misty rain through a reverse zigzag path, and complete the precise positioning of the gas leak source through an inner spiral path or a pendulum spiral path.

2. The gas source autonomous search method based on a two-stage path according to claim 1, characterized in that, The dynamic equation for outputting the robot's dynamic position information in real time through coordinate iteration in S1 is Equation (1): Q k+1 =P k +u k ; (1) Among them, P k =[P kx ,P ky ] T Let P be the robot's current position coordinates, k be the iteration number, and P be the position coordinates. k+1 u is the robot's next coordinate position. k Input for the system; The robot supports adjusting the gas concentration value C(P) based on the current location. k Determine the next target location to visit.

3. The gas source autonomous search method based on a two-stage path according to claim 2, characterized in that, The step in S2, which involves exploring the boundary of the misty rain using an Archimedes spiral path and guiding the robot into the misty rain, includes: S201. Based on the polar coordinate equation of the Archimedes spiral path and the dynamic equation of the robot's dynamic position information, guide the robot's spiral motion. S202. When the concentration detected by the robot is greater than the threshold τ, the current position is determined to be the boundary of the misty rain, and the position of the misty rain boundary is P. s(0) The robot stopped its spiral motion; S203. Based on the dynamic position information of the robot, a dynamic equation guides the robot into the misty rain.

4. The gas source autonomous search method based on a two-stage path according to claim 3, characterized in that, The polar coordinate equations of the Archimedean spiral path in S201 are Equations (2) and (3): P kx =bΘcosΘ+P 0x ; (2) P ky =bΘsinΘ+P 0y ; (3) Where b is the pitch coefficient and b > 0, Θ is the cumulative rotation angle and Θ = kΘ0; Θ0 is the angle increment.

5. The gas source autonomous search method based on a two-stage path according to claim 4, characterized in that, The zigzag path-based tracking of the gas leak source against the wind in the misty rain until the coarse location of the gas leak source is completed includes: S301, drive the robot to switch to zigzag path movement; Wherein, the distance traveled in each step of the zigzag path movement is d. k ; The counterclockwise rotation angle θ is the angle at which the robot switches between any two adjacent line segments. k ; S302. When the maximum concentration in the current line segment of the robot does not exceed q times that of the upper segment, the robot is driven to stop tracking the gas leak source against the wind, and the robot completes the coarse location of the gas leak source. Where 0 < q < 1.

6. The gas source autonomous search method based on a two-stage path according to claim 5, characterized in that, The switching of the drive robot in S301 to a zigzag path motion includes: If C(P) k )≥τ: Then drive the robot to move forward according to step size d1; If C(P) k If τ < τ, and the cumulative step length of the path within the current line segment has not reached the threshold, then the robot is currently inside the misty rain area. Then the robot will move forward with a step length d2; If C(P) k ) < τ, and the cumulative step size of the path within the current line segment reaches the threshold d. s It is determined that the robot is not currently within the misty rain area. The robot is then driven to retreat along the original path into the misty rain with a step size d3, and the robot is driven to rotate in the opposite direction by θ. k .

7. The gas source autonomous search method based on a two-stage path according to claim 6, characterized in that, d in S301 k and θ k With system input u k The relationship satisfies formula (4): Among them, the reference wind direction is defined. If the x-axis is the positive direction, then the rotation angle satisfies formula (5): In s(n), the subscript n represents the corner index, mod is the modulo operator, and n is a non-negative integer.

8. The gas source autonomous search method based on a two-stage path according to claim 7, characterized in that, Based on the coarse positioning results in S4, the robot is guided back to the mist and rain via a reverse zigzag path, and the precise location of the gas leak source is achieved via an inner spiral path or a pendulum spiral path, including: S401. Guide the robot back to the misty rain based on the reverse zigzag path. If the current gas concentration is greater than τ, then determine that the robot has returned to the misty rain. S402. Drive the robot to continue moving along a reverse zigzag path until the current gas concentration is <τ and the previous gas concentration is >τ. When the robot stops moving, the robot is at P. s(e) Stop; S403, with P s(e) Starting from a point, the robot is controlled to search for the gas leak source based on an internal spiral path or a pendulum spiral path, thus obtaining the precise location of the gas leak source.

9. The gas source autonomous search method based on a two-stage path according to claim 8, characterized in that, The step in S401, which guides the robot back to the misty rain based on a reverse zigzag path, includes: The corner constraint condition for the reverse zigzag path is given by formula (6): Where s(f) is the starting index of the reverse zigzag shape; s(e) is the ending index of the reverse zigzag shape; The robot's cumulative threshold for each line segment within the reverse zigzag path is adjusted to d according to step sizes d4, d5, and d6. s ′<d s ; Among them, d4<(d1,d2,d3);, d5<(d1,d2,d3); d6<(d1,d2,d3); The angle subtended by the formation of the reverse zigzag path is less than the angle subtended by the formation of the zigzag path.

10. The gas source autonomous search method based on a two-stage path according to claim 9, characterized in that, In S403, P is used s(e) Starting from a point, the robot is controlled to search for the gas leak source based on an internal spiral path or a pendulum spiral path, obtaining the precise location of the gas leak source, including: When searching for the source of a gas leak along the inner spiral path: The trajectory of the inner spiral path satisfies formula (7): P s(e)x With P s(e)y These are the x and y coordinates of the starting point of the inner spiral path, respectively. r is the polar radius of the helix. P h The midpoint of the previous reverse zigzag line is Θ0′, which is an angle increment smaller than Θ0. r = r0 - b1Θ and r ≥ δ, where δ is the extreme radius threshold of the spiral and b1 is a constant. Φ is the starting point P s(e) To the target point P h rotation angle, The stopping condition for the inner spiral trajectory is: when r decreases to the threshold δ, the robot stops moving, and the point with the highest gas concentration on the current spiral segment is the gas leakage source; When searching for the source of a gas leak by following the spiral path of the inner pendulum: P h It is the midpoint of the previous reverse zigzag line segment; Line segment P s(e) P h According to point P h(1) ,P h(2) To P h(γ) Divided into γ segments; Guide the robot to move clockwise in a spiral from P s(e) Arrival point P h Then, the robot is driven to spiral through line segment P in an alternating clockwise and counterclockwise manner. s(e) P h The segmentation points on; The spiral segment between the two points satisfies formula (8): where r(Θ) = b2(Θ i - Θ)a; Where a = ±1 is the direction factor, +1 represents counterclockwise and -1 represents clockwise; Θ i It is the starting angle, Θ i =Θ j +a·r j / b2,r j b2 is the terminal radius, and b2 is the expansion coefficient. P jx P jy These are the x and y coordinates of the termination point of each spiral segment; P ix P iy These are the x and y coordinates of the starting point of each spiral segment; The robot stops when the concentration at all points on the current spiral segment is less than the threshold τ. The point with the highest gas concentration on the current spiral section is the source of gas leakage.

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