Cyanobacteria monitoring unmanned ship and control method

Abstract

The application relates to a cyanobacteria monitoring unmanned ship and a control method, which comprises a sampling device, a flow cytometer, an edge computing device and a control system; the sampling device is used for sampling lake water and cyanobacteria samples; the flow cytometer is used for receiving the samples collected by the sampling device, and obtaining substance content data and cyanobacteria cell images in the samples; the edge computing device is used for identifying cyanobacteria species according to the substance content data and the cyanobacteria cell images, judging the growth state, and giving a warning; the control system is connected with the sampling device, the flow cytometer and the edge computing device, and is used for receiving and sending information and data; and the control system, the sampling device, the flow cytometer and the edge computing device are all installed in a ship body. The cyanobacteria monitoring unmanned ship and the control method can automatically monitor cyanobacteria without manual operation, and have short time consumption and high efficiency.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of water equipment, in particular to a cyanobacteria monitoring unmanned ship and a control method. BACKGROUND

[0002] Algae is an important primary producer, which undertakes most of the earth's uplift release through photosynthesis, and is one of the main food sources of many animals.

[0003] When the water body is polluted and oxygenated, part of the algae will rapidly reproduce to cause the phenomenon of red tide, and produce a large amount of toxic substances in the water, which will affect the aquatic ecosystem.

[0004] Research on algae recognition technology is to classify and observe the cell state of algae in each growth stage, and then analyze the cell state of algae in different stages to predict whether a water bloom will occur, which can prevent environmental damage caused by large-scale algae reproduction.

[0005] Traditional cyanobacteria detection mostly uses morphological classification and chemical classification methods, which need to be processed and judged manually, which is not conducive to data analysis and maintenance, and is time-consuming and inefficient. SUMMARY

[0006] Therefore, it is necessary to provide a cyanobacteria monitoring unmanned ship and a control method to automatically monitor cyanobacteria, which is time-saving and efficient.

[0007] In a first aspect, the present application provides a cyanobacteria monitoring unmanned ship, comprising:

[0008] A sampling device is configured to sample lake water and cyanobacteria samples.

[0009] A flow cytometer is configured to receive samples collected by the sampling device and obtain substance content data and cyanobacteria cell images in the samples.

[0010] An edge computing device is configured to identify cyanobacteria species and determine growth status based on the substance content data and the cyanobacteria cell images, and give an early warning.

[0011] A control system is connected to the sampling device, the flow cytometer and the edge computing device, and is configured to receive and send information and data.

[0012] In one embodiment, the control system further comprises:

[0013] A gyroscope sensor is connected to the control system to determine whether the ship body is stable and to send the determination information to the control system.

[0014] An adjustable fixed anchor device is connected to the control system to receive the control signal from the control system according to the determination information of whether the ship body is stable, to adjust the position of the anchor, and to stabilize the ship body.

[0015] In one embodiment, the application further comprises:

[0016] A wind speed sensor is connected to the control system to detect the wind speed of the water area where the ship body is located and to send the wind speed information to the control system.

[0017] A water speed sensor is connected to the control system to detect the water flow speed information of the water area where the ship body is located and to send the water flow speed information to the control system.

[0018] The control system calculates the fixed angle information of the anchor required for the current ship body stabilization according to the wind speed information and the water flow speed information, and controls the adjustable fixed anchor device to move the anchor to the calculated fixed angle.

[0019] In one embodiment, the application further comprises a photovoltaic power generation device installed on the top of the ship body, which comprises:

[0020] A photovoltaic module for converting solar energy into electrical energy.

[0021] A storage battery connected to the photovoltaic module for storing electrical energy.

[0022] An inverter connected to the photovoltaic module and the storage battery for converting the direct current generated by the photovoltaic module into alternating current and storing it in the storage battery.

[0023] A controller connected to the storage battery to prevent overcharging or overdischarging of the storage battery.

[0024] In one embodiment, the adjustable fixed anchor device comprises:

[0025] A ring-shaped rotating platform with a movable end that can rotate along the ring;

[0026] A spherical rotating device fixed in the ring-shaped rotating platform and driven by the ring-shaped rotating platform to rotate horizontally, and itself can rotate longitudinally;

[0027] A fixed tube fixed on the spherical rotating device and communicating with the inside of the spherical rotating device.

[0028] A hub is fixed on the annular rotating platform, on which a cable is wound. One end of the cable passes through a spherical rotating device and a fixed pipe and is connected to an anchor.

[0029] In one embodiment, a GPS positioning system is also included, which is connected to the control system and is used to locate the hull to determine whether the hull has reached the designated waters.

[0030] In one embodiment, a wireless transmission module is also included, connected to the control system, for enabling signal transmission between the unmanned vessel and the host computer.

[0031] In one embodiment, the control system is a Raspberry Pi control system.

[0032] In one embodiment, the edge computing device is an NVIDIA Jetson AGX Orin edge computing device.

[0033] Secondly, this application provides a control method for an unmanned surface vessel (USV) used for cyanobacteria monitoring, the method comprising:

[0034] The control system receives positioning signals from the GPS positioning system to determine whether the unmanned vessel has reached the designated waters.

[0035] Start the wind speed sensor, water speed sensor, gyroscope sensor and photovoltaic power generation device;

[0036] Determine whether the unmanned vessel is stable under the current water and wind conditions; if not, then...

[0037] The control system controls the annular rotating platform and the spherical rotating device to rotate to a specified angle;

[0038] The control system controls the hub to adjust the cable length to stabilize the hull; if so, then...

[0039] The sampling device collects samples of lake water and cyanobacteria;

[0040] Flow cytometry was used to acquire data on the content of various substances in the sample and images of cyanobacterial cells.

[0041] The edge computing device judges the growth status of cyanobacteria based on the content data of various substances in the sample and the image of cyanobacteria cells, and issues an early warning.

[0042] Determine whether it is necessary to proceed to the next body of water; if so, then...

[0043] The unmanned boat proceeds to the next body of water; otherwise,

[0044] Return to the starting point.

[0045] The above-mentioned cyanobacteria detection unmanned ship and control method installs the sampling device, flow cytometer, edge computing device and control system in the ship body, drives the ship body to move to the specified water area when the cyanobacteria needs to be monitored, then the sampling end of the sampling device is deep into the water to a certain depth, the water and cyanobacteria in the water are obtained and sent to the flow cytometer, the flow cytometer obtains the content data of various substances and the cyanobacteria cell image in the sample, and sends the data and image to the edge computing device, the edge computing device identifies the cyanobacteria species according to the content data of various substances and the cyanobacteria cell image in the sample sent by the flow cytometer, and analyzes the growth state, so as to judge whether the water area will burst cyanobacteria bloom phenomenon. Without manual operation, the cyanobacteria can be automatically monitored, the time is short and the efficiency is high. BRIEF DESCRIPTION OF DRAWINGS

[0046] Figure 1 It is a schematic diagram of the unmanned ship module of an embodiment.

[0047] Figure 2 It is a schematic diagram of the structure of the adjustable fixed anchor device.

[0048] Figure 3 It is a schematic diagram of the control method flow of the unmanned ship of an embodiment.

[0049] In the figure: 100, control system; 210, sampling device; 220, flow cytometer; 230, edge computing device; 300, wind speed sensor; 400, water speed sensor; 500, gyroscope sensor; 600, adjustable fixed anchor device; 610, annular rotating platform; 620, spherical rotating device; 630, fixed tube; 640, hub; 650, ship anchor; 700, photovoltaic power generation device; 800, GPS positioning system; 900, wireless transmission module. DETAILED DESCRIPTION

[0050] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme of the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0051] It is to be understood that when a component is referred to as being "on" or "connected to" another component, it can be directly on or connected to the other component or intervening components can be present. When a component is referred to as being "connected to" another component, it can be directly connected to the other component or intervening components can be present. The terms "vertical", "horizontal", "upper", "lower", "left", "right", and similar terms as used in this description are merely used for convenience and are not intended to refer to only orientations of the device.

[0052] In addition, the terms "first", "second", etc. are used herein only to describe various conditions, and are not intended to denote or imply these terms referred to are "one-of-a-kind" or "limited to" the quantity of these terms. Thus, the features defined with "first", "second" can explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of "a plurality of" is at least two, for example, two, three, etc., unless otherwise explicitly specified and limited.

[0053] In the present application, unless otherwise explicitly specified and limited, the "on", "under", "above" and "over" of a first feature to a second feature can be that the first feature is directly in contact with the second feature, or the first feature is indirectly in contact with the second feature through an intermediate medium. Moreover, the "on", "above" and "over" of a first feature to a second feature can be that the first feature is directly above or obliquely above the second feature, or only means that the first feature is horizontally higher than the second feature. The "under", "below" and "under" of a first feature to a second feature can be that the first feature is directly below or obliquely below the second feature, or only means that the first feature is horizontally lower than the second feature.

[0054] Unless otherwise defined, all technical and scientific terms used in the present application are intended to have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description of the present application is only for the purpose of describing specific embodiments and is not intended to limit the present application. The term "and / or" used in the description of the present application includes any and all combinations of one or more relevant listed items.

[0055] As Figure 1As shown, in one embodiment, a cyanobacteria monitoring unmanned ship includes a sampling device 210, a flow cytometer 220, an edge computing device 230, and a control system 100; the sampling device 210 is used to sample lake water and cyanobacteria samples; the flow cytometer 220 is used to receive the samples collected by the sampling device 210 and obtain the substance content data and cyanobacteria cell images in the samples; the edge computing device 230 is used to identify the cyanobacteria species and judge the growth state according to the substance content data and cyanobacteria cell images, and give a warning; the control system 100 is connected with the sampling device 210, the flow cytometer 220, and the edge computing device 230, and is used for receiving and sending information and data, and the control system 100, the sampling device 210, the flow cytometer 220, and the edge computing device 230 are all installed in the ship body.

[0056] The above-mentioned cyanobacteria detection unmanned ship installs the sampling device 210, the flow cytometer 220, the edge computing device 230, and the control system 100 in the ship body, drives the ship body to move to a specified water area when cyanobacteria needs to be monitored, then the sampling end of the sampling device 210 is deep into the water to a certain depth, obtains the water body and cyanobacteria in the water, and sends them to the flow cytometer 220, the flow cytometer 220 obtains the substance content data and cyanobacteria cell images in the samples, and sends the data and images to the edge computing device 230, the edge computing device 230 identifies the cyanobacteria species and analyzes the growth state according to the substance content data and cyanobacteria cell images in the samples sent by the flow cytometer 220, so as to judge whether the cyanobacteria bloom phenomenon will occur in the water area. Without manual operation, cyanobacteria monitoring can be automatically performed, which is time-saving and efficient.

[0057] Specifically, the control system 100 is a Raspberry Pi control system 100. Raspberry Pi (Chinese name: Raspberry Pi, abbreviated as RPi, or RasPi / RPI) is designed for computer programming education, which is a microcomputer based on ARM and only the size of a credit card. Its system is based on Linux, and the SD / MicroSD card is used as the internal hard disk. There are 1 / 2 / 4 USB interfaces and a 10 / 100 Ethernet interface (A type without network port) around the card mainboard, which can connect keyboard, mouse and network cable. At the same time, it has a video analog signal TV output interface and an HDMI high-definition video output interface. All the above components are integrated on a mainboard only slightly larger than a credit card, which has all the basic functions of PC. Just connect the TV and keyboard, you can perform many functions such as spreadsheet, word processing, game playing, and playing high-definition video.

[0058] Further, the edge computing device 230 is an NVIDIA Jetson AGX Orin edge computing device 230. The NVIDIA Jetson AGX Orin is a development kit launched by NVIDIA, and its computing power is equivalent to 8-10 times of the mainstream edge computing devices at present. The NVIDIA Jetson AGX Orin edge computing device 230 has a 2048-core NVIDIA Ampere architecture GPU with 64 TensorCores, and uses an ARM instruction set. The edge computing device 230 is deployed with an onnx model of blue-green algae identification based on the EfficientV2-YOLOv5 algorithm, which can identify the category and growth cycle of blue-green algae. The edge computing device 230 is deployed with an onnx model of time-space sequence prediction based on LSTM, which can predict the outbreak date according to the data of various elements in the water body.

[0059] In one embodiment, the cyanobacteria monitoring unmanned ship further comprises a gyroscope sensor 500 and an adjustable fixed anchor device; the gyroscope sensor 500 is connected with the control system 100, and is used for judging whether the ship body is stable, and sending the judgment information of whether the ship body is stable to the control system 100; the adjustable fixed anchor device 600 is connected with the control system 100, and is used for receiving the control signal sent by the control system 100 according to the judgment information of whether the ship body is stable, adjusting the position of the ship anchor 650, and stabilizing the ship body.

[0060] Specifically, the gyroscope can accurately determine the direction of the moving object. In use, the gyroscope sensor 500 will send the ship body running direction information detected by it to the control system 100, and the control system 100 will structure the information and calculate by itself combined with the data of the adjustable fixed anchor device 600, and finally obtain a position of the adjustable fixed anchor device 600 which can stabilize the ship body. According to the position information of the adjustable fixed anchor device 600 obtained by calculation, the control system 100 will control the adjustable fixed anchor device 600 to run to the calculated state.

[0061] As shown in FIG. 6, the adjustable fixed anchor device 600 is connected with the control system 100, and is used for receiving the control signal sent by the control system 100 according to the judgment information of whether the ship body is stable, adjusting the position of the ship anchor 650, and stabilizing the ship body. Figure 2As shown, in one embodiment, the adjustable fixed anchor device 600 comprises a ring-shaped rotating platform 610, a spherical rotating device 620, a fixed tube 630 and a hub 640; the movable end of the ring-shaped rotating platform 610 can rotate along the ring; the spherical rotating device 620 is fixed in the ring-shaped rotating platform 610 and can be driven by the ring-shaped rotating platform 610 to rotate horizontally and can rotate longitudinally by itself; the fixed tube 630 is fixed on the spherical rotating device 620 and is in communication with the inside of the spherical rotating device 620; the hub 640 is fixed on the ring-shaped rotating platform 610 and has a cable wound thereon, one end of the cable passes through the spherical rotating device 620 and the fixed tube 630 in sequence and is connected with a ship anchor 650.

[0062] Specifically, first, the ring-shaped rotating platform 610 operates to make the rotating direction of the spherical rotating device 620 face the calculated position, and then the spherical rotating device 620 operates to move the fixed tube 630 to face a certain angle, at this time, the hub 640 can be operated to release the cable until the ship anchor 650 connected at the end of the cable is at the bottom of the water area, at this time, the hub 640 winds the cable until the cable between the ship anchor 650 and the ship body is taut, thereby realizing the stabilization of the ship body.

[0063] In one embodiment, the cyanobacteria monitoring unmanned ship further comprises a wind speed sensor 300 and a water speed sensor 400; the wind speed sensor 300 is connected with the control system 100 and is used for detecting the wind speed of the water area where the ship body is located and sending the wind speed information to the control system 100; the water speed sensor 400 is connected with the control system 100 and is used for detecting the water flow speed information of the water area where the ship body is located and sending the water flow speed information to the control system 100; the control system 100 calculates the fixed angle information of the ship anchor 650 required for the current stabilization of the ship body according to the wind speed information and the water flow speed information and controls the adjustable fixed anchor device 600 to move the ship anchor 650 to the calculated fixed angle.

[0064] Specifically, the wind speed sensor 300 and the water speed sensor 400 send the wind speed and the water flow speed of the water area where the ship body is located to the control system 100, the control system 100 combines the gyro sensor 500 to judge the direction of the force acting on the ship body and the stabilization condition of the ship body, then calculates the position of the ship anchor 650 of the adjustable fixed anchor device 600, and finally calculates that when the ship anchor 650 is located at a certain position, the ship body can reach a balance under the comprehensive force of the ship anchor 650, the wind force and the water force.

[0065] In an embodiment, the cyanobacteria monitoring unmanned ship further comprises a photovoltaic power generation device 700 installed on the top of the ship body, the photovoltaic power generation device 700 comprising a photovoltaic assembly, a storage battery, an inverter and a controller; the photovoltaic assembly is used to convert solar energy into electric energy; the storage battery is connected with the photovoltaic assembly and is used to store the electric energy; the inverter is connected with the photovoltaic assembly and the storage battery and is used to convert the direct current generated by the photovoltaic assembly into alternating current and store it in the storage battery; the controller is connected with the storage battery and is used to prevent overcharging or overdischarging of the storage battery.

[0066] Specifically, the photovoltaic power generation device 700 is connected with a plurality of electrical devices installed on the ship body and is used to supply power for the unmanned ship power system and cyanobacteria monitoring.

[0067] In an embodiment, the cyanobacteria monitoring unmanned ship further comprises a GPS positioning system 800 connected with the control system 100 and used to position the ship body so as to determine whether the ship body reaches the designated water area.

[0068] Specifically, the position of the ship body is determined by the GPS positioning system 800 so as to determine whether the ship body reaches the designated area or travels to the next area.

[0069] In an embodiment, the cyanobacteria monitoring unmanned ship further comprises a wireless transmission module 900 connected with the control system 100 and used to realize signal transmission between the unmanned ship and the upper computer.

[0070] Specifically, the cyanobacteria information monitored by the unmanned ship and the current condition of the ship body can be accurately transmitted to the upper computer for remote monitoring personnel to check through the wireless transmission module 900.

[0071] As shown in Figure 3 In an embodiment, a cyanobacteria monitoring unmanned ship control method comprises the following steps:

[0072] Step S310: The control system receives the positioning signal of the GPS positioning system and determines whether the unmanned ship reaches the designated water area.

[0073] Step S320: The wind speed sensor, the water speed sensor, the gyroscope sensor and the photovoltaic power generation device are started.

[0074] Step S330: It is determined whether the unmanned ship is stable under the current water and wind condition; if not, the

[0075] Step S340: The control system controls the ring-shaped rotating platform and the spherical rotating device to rotate to a specified angle.

[0076] Step S350: The control system controls the hub to adjust the length of the cable to stabilize the ship body; if yes, the

[0077] Step S360, the sampling device samples the lake water and the cyanobacteria sample;

[0078] Step S370, the flow cytometer acquires the substance content data and the cyanobacteria cell image in the sample;

[0079] Step S380, the edge computing device judges the growth state of the cyanobacteria according to the substance content data and the cyanobacteria cell image in the sample, and gives a warning;

[0080] Step S390, it is judged whether to go to the next water area, if yes, then

[0081] Step S3100, the unmanned ship goes to the next water area, and step S310 is executed again; if no, then

[0082] Step S3110, return to the starting point.

[0083] The above-mentioned cyanobacteria detection unmanned ship control method judges the stability of the ship body through the wind speed sensor 300, the water speed sensor 400 and the gyroscope sensor 500, and predicts the balance state of the ship body through the control system 100 combined with the adjustable fixed anchor device 600, until the ship body reaches balance when the ship anchor 650 of the adjustable fixed anchor device 600 is in a certain position, then the control system 100 controls the adjustable fixed anchor device 600 to adjust the ship anchor 650 to the predicted position and fix the ship body, then the sampling end of the sampling device 210 is deep into the water to a certain depth to acquire the water body and cyanobacteria in the water and send them to the flow cytometer 220, the flow cytometer 220 acquires the substance content data and the cyanobacteria cell image in the sample, and sends the data and the image to the edge computing device 230, the edge computing device 230 analyzes the growth state of the cyanobacteria according to the substance content data and the cyanobacteria cell image in the sample sent by the flow cytometer 220, so as to judge whether the water area will break out cyanobacteria bloom phenomenon. Without manual operation, cyanobacteria monitoring can be automatically performed, which is time-saving and efficient.

[0084] The technical features of the above-mentioned embodiments can be combined arbitrarily, in order to make the description simple, not all possible combinations of the technical features in the above-mentioned embodiments are described, however, as long as the combination of the technical features does not exist contradictory, it should be considered as the scope of the description.

[0085] The above-mentioned embodiments only express several implementation manners of the present application, the description is more specific and detailed, but it cannot be understood as the limitation of the patent scope of the present application. It should be pointed out that for ordinary skilled in the art, without departing from the concept of the present application, several modifications and improvements can be made, which belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. A cyanobacteria monitoring unmanned ship, characterized by, The utility model relates to a kind of lake blue-green algae early warning system, including: Sampling device for sampling lake water and blue-green algae samples; Flow cytometer for receiving samples collected by the sampling device and obtaining substance content data and blue-green algae cell images in the samples; Edge computing device for identifying blue-green algae species and determining growth state based on the substance content data and blue-green algae cell images, and giving early warning, wherein an onnx model based on EfficientV2-YOLOv5 algorithm for blue-green algae identification is deployed on the edge computing device, which can identify the category and growth cycle of blue-green algae;An onnx model based on LSTM for time-space sequence prediction is deployed on the edge computing device to predict the outbreak date based on various element substance content data in the water body; Control system connected to the sampling device, flow cytometer and edge computing device for receiving and sending information and data, and the control system, sampling device, flow cytometer and edge computing device are all installed in the ship body; It also includes a gyroscope sensor connected to the control system for determining whether the ship body is stable and sending the determination information to the control system; Adjustable fixed anchor device connected to the control system for receiving control signals from the control system based on the determination information of whether the ship body is stable to adjust the position of the anchor and stabilize the ship body, wherein the adjustable fixed anchor device includes: Annular rotating platform with a movable end that can rotate along the annular shape; Spherical rotating device fixed in the annular rotating platform and horizontally rotatable by the annular rotating platform, and longitudinally rotatable by itself; Fixed tube fixed on the spherical rotating device and in communication with the inside of the spherical rotating device; Hub fixed on the annular rotating platform with a cable wound thereon, one end of the cable connected to the anchor by passing through the spherical rotating device and the fixed tube in sequence.

2. The cyanobacteria monitoring unmanned ship of claim 1, wherein It also includes: Wind speed sensor connected to the control system for detecting the wind speed of the water area where the ship body is located and sending the wind speed information to the control system; Water speed sensor connected to the control system for detecting the water flow speed information of the water area where the ship body is located and sending the water flow speed information to the control system; The control system calculates the anchor fixing angle information required for the current ship body stabilization based on the wind speed information and water flow speed information, and controls the adjustable fixed anchor device to move the anchor to the calculated fixing angle.

3. The cyanobacteria monitoring unmanned ship of claim 2, wherein It also includes a photovoltaic power generation device installed on the top of the ship body, which includes: Photovoltaic module for converting solar energy into electrical energy; Battery connected to the photovoltaic module for storing electrical energy; Inverter connected to the photovoltaic module and the battery for converting direct current generated by the photovoltaic module into alternating current and storing it in the battery; Controller connected to the battery for preventing overcharging or overdischarging of the battery.

4. The cyanobacteria monitoring unmanned ship of claim 1, wherein The GPS positioning system is connected with the control system and is used for positioning the ship body to determine whether the ship body reaches the designated water area.

5. The cyanobacteria monitoring unmanned ship of claim 4, wherein, The wireless transmission module is connected with the control system and is used for realizing signal transmission between the unmanned ship and the upper computer.

6. The cyanobacteria monitoring unmanned ship of claim 1, wherein The control system is a Raspberry Pi control system.

7. The cyanobacteria monitoring unmanned ship of claim 6, wherein, The edge computing device is an NVIDIA Jetson AGX Orin edge computing device. 8.A cyanobacteria monitoring unmanned ship control method, characterized by, Based on the cyanobacteria monitoring unmanned ship in claim 1, the method comprises: The control system receives the positioning signal of the GPS positioning system to determine whether the unmanned ship reaches the designated water area. The wind speed sensor, the water speed sensor, the gyroscope sensor and the photovoltaic power generation device are started. It is determined whether the unmanned ship is stable under the current water and wind conditions, and if not, The control system controls the annular rotating platform and the spherical rotating device to rotate to a specified angle. The control system controls the hub to adjust the length of the cable to stabilize the ship body; if yes, The sampling device samples the lake water and cyanobacteria samples; The flow cytometer obtains the substance content data and cyanobacteria cell images in the samples; The edge computing device determines the growth state of the cyanobacteria according to the substance content data and cyanobacteria cell images in the samples and gives a warning; It is determined whether it is necessary to go to the next water area, and if yes, The unmanned ship goes to the next water area; if not, Return to the starting point.

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