CN112083749B - Unmanned aerial vehicle spraying intelligence control system - Google Patents

Abstract

The invention provides an unmanned aerial vehicle spraying intelligent control system, which comprises: the controller is used for carrying out temperature adjustment on the temperature control circuit, pressure adjustment on the pressure control circuit, the temperature acquisition circuit and the pressure acquisition circuit; the controller is respectively connected with the temperature control circuit, the pressure control circuit, the temperature acquisition circuit and the pressure acquisition circuit; the temperature control circuit is characterized in that a temperature control output terminal of the controller is connected with the temperature control switch, so that the on-off of the temperature control switch is controlled according to an output signal of the controller; the pressure control circuit adopts a mode of controlling the motor by an external frequency converter so as to control the pressure of the pipeline. According to the invention, through double detection and double control of temperature and pressure, the spraying system is not overheated or fails due to overpressure; when the pressure and the temperature are out of control and the equipment state is abnormal, the alarm can be given for the first time to avoid danger, and the reliability and the stability of the system are greatly improved.

Description

A drone spray intelligent control system

technical field

The invention relates to the field of control, in particular to an intelligent control system for unmanned aerial vehicle spraying based on temperature and pressure monitoring, which is especially suitable for precise drug application by unmanned aerial vehicles.

Background technique

With the development of smart agriculture, various types of spraying equipment are widely used to meet the needs of various agricultural planting scenarios. Among them, the spraying method of drones has been greatly promoted due to its advantages of high efficiency, wide range and convenience.

For drone spraying, temperature and pressure are the prerequisites for precise spraying. If the temperature and pressure are too low in the process of drone spraying, the number of droplets generated by atomization will be insufficient, and the temperature and pressure will be too high. , which will lead to chemical reaction of the sprayed drug and lose its efficacy. From a safety point of view, it is also necessary to ensure that the temperature and pressure values generated by the drone spray device are within safe indicators to avoid explosion due to excessive temperature or pressure.

However, the existing UAV spraying systems have not been able to solve the problems of temperature and pressure during the spraying process. For example, if pressurized continuously, violently pressurized, etc., it is easy to produce explosion. In addition, the existing drone spray system cannot effectively identify when the state changes abnormally during use, and cannot solve the problem in a timely and efficient manner when a fault occurs. For example, when the cavity is worn and aged, resulting in pressure leakage, more serious damage may occur if it cannot be handled in time.

Therefore, how to realize spray control more intelligently is a major problem that needs to be solved urgently.

SUMMARY OF THE INVENTION

In order to overcome the above-mentioned defects in the prior art, the present invention proposes an efficient and safe drone spraying intelligent control system, which can be applied to various usage scenarios requiring heating and pressurization, including precise drug application by drones, achieving The advantages of safety and explosion-proof are taken into account while heating and pressurizing efficiently, the structure is simple, and the control is convenient.

In order to achieve the purpose of the present invention, the present invention provides an intelligent spray control system for an unmanned aerial vehicle, comprising: a controller, a temperature control circuit for temperature adjustment, a pressure control circuit for pressure adjustment, a temperature acquisition circuit, a pressure acquisition circuit; the controller is respectively connected with the temperature control circuit, the pressure control circuit, the temperature acquisition circuit and the pressure acquisition circuit; it also includes a power supply circuit for supplying power to each power-consuming circuit in the system;

The temperature control circuit is specifically that the temperature control output terminal of the controller is connected to the temperature control switch, so as to control the on-off of the temperature control switch according to the output signal of the controller. When the temperature detection value obtained from the temperature acquisition circuit is greater than the upper temperature limit Turn off the temperature control switch to stop heating when the detected temperature value is lower than the lower limit, and turn on the temperature control switch to start heating;

The pressure control circuit adopts an external frequency converter to control the motor and then controls the pipeline pressure, which specifically includes: the pressure switch output terminal of the controller is connected to the coil control side of the AC contactor, which is used to control the on-off of the AC contactor switch, control the The pressure analog output terminal of the pressure sensor is connected to the control input end of the frequency converter, which is used to control the output of the frequency converter to adjust the speed of the motor; when the pressure detection value obtained from the pressure sensor is less than or equal to the lower limit value, the controller will output the switch The quantity signal controls the coil of the AC contactor to be energized, and the switch on the switch side of the AC KM1 switch is finally connected to the power supply of the motor, and the pressure analog output terminal of the controller simultaneously inputs the corresponding first control value to the inverter; when the pressure detection value is greater than When the upper limit value is reached, reduce the pressure by controlling the inverter.

Further, the AC power supply, the controlled switch side of the AC contactor KM1, the frequency converter, and the motor are connected in series to form a motor circuit; the first control value is increased from small to large, and the control algorithm is a fuzzy control algorithm.

Further, the read temperature acquisition circuit adopts a PT100 platinum resistance temperature sensor, which is connected to the temperature detection terminal of the controller through a temperature transmitter. Preferably, the temperature transmitter outputs a standard 4-20mA or 0-20mA. The pressure acquisition circuit adopts a pressure sensor, which is connected to the pressure detection terminal of the controller through a pressure transmitter.

In addition, the controller is also connected with: a crystal oscillator circuit, which is used to provide the time reference of the working sequence of the controller; a reset circuit, which is used to realize power-on reset and fault reset; a button circuit, which is used to input setting parameters; a collection indication circuit, which is used for Work instructions for temperature and pressure detection; display circuit for working status display; alarm output circuit for abnormal alarm.

The alarm output circuit includes a buzzer, which will give a buzzer alarm when it is abnormal; the alarm output circuit also includes a communication circuit, which can remotely alarm through the wireless network when it is abnormal, so that the maintenance personnel can receive the fault prompt at the first time and promptly. to be processed.

Specifically, when it is detected that the temperature is higher than the upper limit of the temperature for a predetermined number of consecutive times or when the pressure is higher than the upper limit of the pressure for a predetermined number of consecutive times, an abnormal alarm is issued by the alarm output circuit.

Further: every time after the end of spraying, when receiving a stop signal, the controller also performs the following operations: 1) The controller first outputs a control signal to maintain the current temperature and stop pressurization, and at the same time checks the current pressure value PD1; 2 ) After a predetermined time TD, check the pressure value PD2 again, judge the pressure change rate (PD1-PD2)/TD in a constant temperature environment after shutdown, and record and store it; 3) Stop heating, and analyze the current rate of change and historical changes When the deviation is large, it is confirmed that the components are abnormal, and the maintenance personnel are reminded through the alarm output circuit.

The UAV spray intelligent control system of the present invention fills the technical gap in the existing UAV spray control field, and through the dual detection and dual control of temperature and pressure, the spray system will not fail due to overheating or overpressure; further , when the pressure and temperature are out of control, it can give an alarm at the first time to prevent the occurrence of danger.

The present invention also proposes a further optimization scheme: creatively utilize the time when the system is shut down to accurately collect state data, so as to detect the abnormal state of the implement at the first time, and improve the maintenance efficiency by notifying the maintenance personnel. Among them, the state data is obtained based on the natural change of pressure under constant temperature conditions, which avoids the influence of internal and external heat exchange, thus ensuring the accuracy of the analysis results to the greatest extent. Through the cooperation of various means, the present invention can efficiently and intelligently perceive the state of the equipment, perform output control and give early warning in time, which greatly improves the reliability and stability of the system.

Other features and advantages of the present invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention may be realized and attained by the structure particularly pointed out in the description, claims and drawings.

Description of drawings

The accompanying drawings are used to provide a further understanding of the technical solutions of the present invention, and constitute a part of the specification. They are used to explain the technical solutions of the present invention together with the embodiments of the present application, and do not limit the technical solutions of the present invention.

1 is a schematic structural diagram of a drone spray intelligent control system provided by an embodiment of the present invention;

2 is a schematic diagram of the wiring of a drone spray intelligent control system provided by an embodiment of the present invention;

FIG. 3 is a pin diagram of an AT89C51 single-chip microcomputer provided by an embodiment of the present invention;

4 is a schematic diagram of a temperature and pressure acquisition circuit provided by an embodiment of the present invention;

FIG. 5 is a flowchart of a system control method provided by an embodiment of the present invention;

FIG. 6 is a simulation experiment diagram of an intelligent control system provided by an embodiment of the present invention.

Detailed ways

In order to make the objectives, technical solutions and advantages of the present invention clearer, the embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that, the embodiments in the present application and the features in the embodiments can be arbitrarily combined with each other as required.

The system of the present invention will be described below with reference to FIG. 1 . As shown in FIG. 1 , the present invention proposes an intelligent control system for unmanned aerial vehicle spraying, including: a controller, which can be realized by a single-chip microcomputer; a temperature control circuit, which is used for temperature adjustment; and a pressure control circuit, which is used for pressure adjustment; Pressure acquisition circuit; temperature acquisition circuit; power supply circuit, used to supply power to each power module in the system.

Optionally, the controller is further connected with: a crystal oscillator circuit, used to provide a time reference for the working sequence of the controller; a reset circuit, used to realize power-on reset and fault reset; a key circuit, used to input setting parameters; a collection indication circuit, It is used for working instructions during temperature and pressure detection; display circuit is used for working status display; alarm output circuit is used for abnormal alarm.

Figure 2 further illustrates the wiring diagram of the drone spray intelligent control system, in which the peripheral circuits of the single-chip microcomputer such as the crystal oscillator circuit, the reset circuit, and the key circuit are connected to the single-chip microcomputer respectively, and placed on the PCB together to obtain the single-chip control board. 51 single-chip development board and other mature solutions are implemented, which will not be repeated here.

The read temperature acquisition circuit adopts PT100 platinum resistance temperature sensor, which has the advantages of high precision and convenient use, and can be used for long-distance transmission with a special temperature transmitter. The principle of temperature measurement through PT100 platinum resistance is that the PT100 platinum resistance sensor will change its own resistance value according to the temperature. The dedicated transmitter only needs to be connected to PT100 platinum resistance and power supply to output standard 4-20mA or 0-20mA signal, preferably 0-20mA output signal. The current signal is selected because the transmitter is equivalent to the output of a constant current source when it is transmitted over a long distance, which reduces the error caused by the line resistance. When the temperature sensor is connected to the control board in the embodiment through the temperature transmitter, the Convert the current signal to a 0-5V voltage signal by connecting a 250 ohm resistor in series.

The pressure acquisition circuit adopts the pressure sensor and transmitter method. The pressure acquisition principle is similar to the temperature acquisition principle. The difference is that the front-end sensor is replaced by a PT100 pressure sensor, and the transmitter is a pressure transmitter that transmits pressure signals.

The temperature control circuit is specifically that the temperature control output terminal of the controller is connected to the temperature control switch, so as to control the on-off of the temperature control switch according to the output signal of the controller. The temperature control output adopts the switch output mode. The control mode is to turn off the temperature control switch to stop heating when the temperature detection value obtained from the temperature sensor is greater than the upper temperature limit, and turn on the temperature control when the temperature detection value is less than the lower limit value. switch to start heating.

The pressure control circuit adopts an external frequency converter to control the motor, thereby controlling the pipeline pressure. Specifically, the pressure switch output terminal of the controller is connected to the coil control side of the AC contactor KM1, which is used to control the on-off of the AC contactor switch; the pressure analog output terminal of the controller is connected to the control input end of the inverter, used for Control the output of the inverter to adjust the speed of the motor. The AC power supply, the air switch QS, the controlled switch side of the AC contactor KM1, the inverter, and the motor are connected in series to form a motor circuit. The pressure control method is that when the pressure detection value obtained from the pressure sensor is less than the lower limit value, the control board will output the switch signal to control the coil of the AC contactor to energize and turn on the switch on the switch side of the AC KM1 switch and finally turn on the power supply of the motor. The pressure analog output terminal of the board simultaneously inputs the corresponding first control value to the inverter; when the pressure detection value is greater than the upper limit, the inverter is controlled to reduce the pressure.

The first control value is increased from small to large, so as to avoid overpressure explosion caused by high pressure at the beginning. The control algorithm preferably adopts a fuzzy control algorithm, and obtains the pressure value change ΔP by detecting the pressure values before and after within a certain period of time. If the change ΔP is less than or equal to the predetermined value (smaller), it means that the given pressure value is small. If the change is within the allowable range, it means that the given value is appropriate. If the change exceeds the predetermined value, it means that the given value is too large and needs to be reduced. The design of this embodiment is divided into 6 grades by default, that is, the 6 grades of the pressure difference ΔP are: grade 1: less than or equal to 0.05MPa; grade 2: greater than 0.05MPa and less than or equal to 0.1MPa; grade 3: greater than 0.1MPa And less than or equal to 0.15MPa; 4th gear: greater than 0.15MPa and less than or equal to 0.2MPa; 5th gear: greater than 0.2MPa and less than or equal to 0.25MPa; 6th gear: greater than 0.25MPa and less than or equal to 0.3Mpa. Different adjustment rates are used according to the different gears in which ΔP is located.

The collection indication circuit indicates the temperature through the first indicator light and the pressure through the second indicator light. The alarm output circuit includes a buzzer to give a buzzer alarm when abnormal; it can also include a communication circuit to remotely alarm through a wireless network when abnormal, so that maintenance personnel can receive the fault prompt at the first time and deal with it in time.

The single-chip microcomputer can be selected from AT89C51, and its pin diagram is shown in Figure 3. For the description of the functions of each pin, please refer to the chip manual.

The pressure sensor is a hydraulic pressure sensor, such as a flat film sensor. Its working principle is: the pressure directly acts on the thin film of the sensor, causing the diaphragm to produce a small displacement proportional to the pressure of the medium, so that the resistance of the sensor changes, and then the electronic circuit is used to detect this change, and the conversion output corresponds to a The standard electrical signal of this pressure.

Combined with Figure 4, the acquisition of two analog quantities of temperature and pressure can share a conversion chip, such as the PCF8591 shown in Figure 4. PCF8591 chip is a chip with 4 analog inputs, 1 analog output and IIC bus. Up to 8 PCF8591 chips can be hung on this IIC bus. The temperature acquisition occupies the first analog acquisition channel AN0, that is, AN0 is connected to the temperature sensor; the pressure acquisition occupies the second analog acquisition channel, AN1, that is, AN1 is connected to the pressure sensor; the analog output is connected to AOUT, that is, J6, and passed to the controller, The signal level here is a level signal of 0-5V. The SCL and SDA pins of PCF8591 are respectively connected to the P1.0 and P1.1 pins of the microcontroller.

The intelligent control method based on the above-mentioned control system will be described below. The method is based on the detection of temperature and pressure, and further perfects the control of the state of the existing UAV spray equipment. As shown in Figure 5, the method includes the following steps:

After the power-on is completed, the system first initializes. After the initialization is completed, the temperature and pressure values are regularly collected, and then it is judged whether each value is within the normal range. If it is not within the range, the corresponding operation is performed;

Specifically, when the temperature detection value is lower than the temperature lower limit t1, the control end of the controller turns on the temperature control switch to start heating, and when the temperature detection value is higher than the temperature upper limit t2, the controller turns off the temperature control switch to stop heating; when When the temperature detection value is in the interval [t1, t2], keep the temperature constant; when the pressure detection value is lower than the pressure lower limit p1, start the motor to work, gradually increase the pressure through frequency conversion control, and carry out fuzzy control according to the boosting situation; when When the pressure detection value is higher than the upper limit p2, the pressure is gradually reduced through frequency conversion control; when the pressure detection value is in the interval [p1, p2], the pressure is maintained constant. where t1<t2, p1<p2.

Combined with the fuzzy control algorithm mentioned above. The AN0 channel of the PCF8591 chip is connected to the temperature analog input, and the AN1 channel of the PCF8591 chip is connected to the pressure analog input, and the output can indicate the temperature value and the pressure value on the display circuit. The fuzzy control adopted in the present invention is as follows: the magnitude of the boost is controlled according to the pressure difference value collected before and after two times and the established fuzzy table. In which interval in the fuzzy table the difference of this pressure is, the corresponding output is given. When the difference is too large, the inverter will be controlled to boost the voltage in full, and when the difference is appropriate, the boost will be controlled at medium speed. When the difference is too small, boost the voltage at a small rate.

When it is detected that the temperature is higher than the upper limit of the temperature for a predetermined number of consecutive times, or when the pressure is detected to be higher than the upper limit of the pressure for a predetermined number of consecutive times, an abnormal alarm is issued through the alarm output circuit.

Further, the control method further includes a key detection subroutine for judging whether there is a key event to implement intervention control, such as forced shutdown, upper limit setting, lower limit setting, and the like. Through the above method, timely troubleshooting and alarming can be effectively implemented.

In order to overcome the problem that the state of the components cannot be detected in time in the prior art, the present invention also proposes the following concept: every time after the spraying ends, when a shutdown signal is received, the state inspection subroutine is started, and the specific operations are as follows:

1) The controller first outputs a control signal to maintain the current temperature and stop pressurization, and at the same time checks the pressure value PD1 at the current moment;

2) After a predetermined time TD, the pressure value PD2 is detected again, and the pressure change rate (PD1-PD2)/TD in a constant temperature environment after the shutdown is judged, and it is recorded and stored;

3) Stop heating, and analyze the deviation between the current rate of change and the historical rate of change. When the deviation is large (more than the normal range), confirm that the component is abnormal, and remind the maintenance personnel through the alarm output circuit.

The invention creatively combines state monitoring with the recovery time of the machine after shutdown, which can efficiently and intelligently perceive the state of the equipment and give early warning; and by maintaining constant temperature conditions, it avoids the deviation of pressure sensing results caused by heat changes, and improves the accuracy of analysis results. accuracy. The above-mentioned concept solves the defects in the prior art, and greatly improves the reliability and stability of the system.

Although the embodiments disclosed in the present invention are as above, the described contents are only the embodiments adopted to facilitate the understanding of the present invention, and are not intended to limit the present invention. Any person skilled in the art to which the present invention pertains, without departing from the spirit and scope of the present invention, can make any modifications and changes in the form and details of the implementation, which all belong to the protection scope of the present invention. Therefore, the scope of the patent protection of the present invention shall still be subject to the scope defined by the appended claims.

Claims (5)

1. A drone spray intelligent control system, comprising: a controller, a temperature control circuit for temperature adjustment, a pressure control circuit for pressure adjustment, a temperature acquisition circuit, and a pressure acquisition circuit; The control circuit, the pressure control circuit, the temperature acquisition circuit, and the pressure acquisition circuit are respectively connected; it also includes a power supply circuit for supplying power to each electric circuit in the system; it is characterized in that: The temperature control circuit is specifically that the temperature control output terminal of the controller is connected to the temperature control switch, so as to control the on-off of the temperature control switch according to the output signal of the controller, when the temperature detection value obtained from the temperature acquisition circuit is greater than the temperature upper limit value Turn off the temperature control switch to stop heating, and when the temperature detection value is less than the lower limit, turn on the temperature control switch to start heating; The pressure control circuit adopts an external frequency converter to control the motor and then controls the pipeline pressure, which specifically includes: the pressure switch output terminal of the controller is connected to the coil control side of the AC contactor, which is used to control the on-off of the AC contactor switch, control the The pressure analog output terminal of the pressure sensor is connected to the control input end of the frequency converter, which is used to control the output of the frequency converter to adjust the speed of the motor; when the pressure detection value obtained from the pressure sensor is less than or equal to the lower limit value, the controller will output the switch The quantity signal controls the coil of the AC contactor to be energized, and the switch on the switch side of the AC KM1 switch is finally connected to the power supply of the motor, and the pressure analog output terminal of the controller simultaneously inputs the corresponding first control value to the inverter; when the pressure detection value is greater than When the upper limit value is reached, reduce the pressure by controlling the inverter; The AC power supply, the controlled switch side of the AC contactor KM1, the frequency converter and the motor are connected in series to form a motor circuit; the first control value is increased from small to large, and the control algorithm is a fuzzy control algorithm; The read temperature acquisition circuit adopts PT100 platinum resistance temperature sensor, which is connected to the temperature detection terminal of the controller through a temperature transmitter, and the temperature transmitter outputs a standard 4-20mA or 0-20mA signal; Among them, the fuzzy control is as follows: the magnitude of the boost is controlled according to the pressure difference value collected before and after two times and the established fuzzy table. When the pressure value collected before and after the two times is detected within a predetermined length of time, the pressure value is determined. In which interval in the fuzzy table the difference value of , the corresponding output is given; when the difference value is too large, the inverter will be controlled to boost the voltage in full; If the value is too small, boost the voltage at a small rate; Every time after the spraying is over, the controller also performs the following operations when receiving the stop signal: 1) The controller first outputs a control signal to maintain the current temperature and stop pressurization, and at the same time checks the pressure value PD1 at the current moment; 2) After a predetermined time TD, the real-time pressure value PD2 is detected again, and the pressure change rate (PD1-PD2)/TD under the constant temperature environment after the shutdown is judged, and it is recorded and stored; 3) Stop heating, and analyze the deviation between the current rate of change and the historical rate of change. When the deviation is large, it is confirmed that the component is abnormal, and the maintenance personnel are reminded through the alarm output circuit; The larger deviation means greater than the normal range. 2 . The control system according to claim 1 , wherein the pressure acquisition circuit adopts a pressure sensor, which is connected to the pressure detection terminal of the controller through a pressure transmitter. 3 . 3. The control system according to claim 1, wherein the controller is also connected with: a crystal oscillator circuit, for providing a time reference of the controller working sequence; a reset circuit, for realizing power-on reset and fault reset; The circuit is used for inputting the setting parameters; the collection indication circuit is used for the work indication when temperature and pressure are detected; the display circuit is used for the working status display; the alarm output circuit is used for abnormal alarm. 4 . The control system according to claim 3 , wherein the alarm output circuit comprises a buzzer, which performs a buzzer alarm when abnormality occurs; the alarm output circuit further comprises a communication circuit for wirelessly Network remote alarms enable maintenance personnel to receive fault prompts at the first time and deal with them in time. 5. The control system according to any one of claims 1-4, characterized in that, when it is detected that the temperature is higher than the upper temperature limit for a predetermined number of times or the pressure is higher than the upper limit of the pressure for a predetermined number of consecutive times, an alarm is issued. The output circuit issues an abnormal alarm.

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