Adaptive control method for a vehicle-mounted compressed air foam generating unit

Abstract

The application discloses a self-adaptive control method for a vehicle-mounted compressed air foam generating unit, and the control method comprises the following steps: S1, collecting instruction information; S2, controlling the water flow regulating valve based on an algorithm to control the water at a desired opening; S3, collecting the water flow signal to calculate the required foam concentrate and compressed air flow; S4, controlling the foam pump speed based on an algorithm to make the foam concentrate at a desired flow; S5, controlling the compressed air flow regulating valve based on an algorithm to make the compressed air at a desired flow; and S6, balancing the water and compressed air pressure in the algorithm control unit. The application is based on the existing technical scheme, and the hardware and the control method are optimized and upgraded, so that each unit can be independently adjusted without interference, and the range of different types of foam extinguishing can be steplessly adjusted, and the stability, applicability and extinguishing efficiency of the system are improved.

Description

Technical Field

[0001] This invention relates to the field of fire trucks, and more particularly to an adaptive control method for onboard compressed air foam generating units. Background Technology

[0002] A compressed air foam fire truck is a fire truck equipped with a compressed air foam generator. It first mixes foaming agent with water to form a foam mixture, then mixes it with compressed air to create foam, and finally sprays it onto the fire scene through fire hoses or fire monitors to form a foam with wide coverage and good fire extinguishing effect.

[0003] Compressed air foam fire trucks are typically equipped with multiple fire nozzles or fire monitors of different models. Each fire nozzle or fire monitor is equipped with a compressed air foam generating unit, and water and compressed air are supplied to all units through a fire pump and an on-board air compressor. The total compressed air flow rate is a constant value, and the water flow rate of each unit is regulated by a water flow regulating valve. Especially when generating Class A foam, because the compressed air flow rate is constant, changes in the current water flow rate will cause the foam type to change accordingly. This control method has the following problems:

[0004] Question 1: If the flow rate on one branch is changed under steady-state conditions, since the total flow rate remains unchanged, it will affect the flow rate on other branches, and thus affect the fire extinguishing effect of other branches.

[0005] Question 2: Existing products generally use a pressure balancing valve to regulate the balance between the total outlet pressure of a fire pump and a vehicle-mounted air compressor. If the flow rate within the unit changes, it will affect the change in total pressure, thereby affecting the pressure balance and also affecting the system stability of other units.

[0006] Question 3: Since the system pressure will automatically remain basically constant, the range is related to the flow rate. Assuming that the current fire is suitable for Class A dry foam fire extinguishing, the valve opening is 50%, but the range is 25m. If you want to increase the flow rate and range, you need to further open the water flow valve. However, as the valve is opened, it will become Class A wet foam, which is not suitable for the current fire extinguishing and will affect the current fire extinguishing efficiency.

[0007] Therefore, to solve the above problems, it is urgent to develop a unit in which the flow rate, pressure, and mixing ratio of each branch can be independently controlled. This would greatly reduce the influence of other units on the pressure and flow rate within the unit, ensuring that they do not interfere with each other and improving the stability of the system. Furthermore, when the opening of the water branch flow regulating valve is adjusted from 0 to 100%, an adaptive algorithm can be used to adjust the flow rates of foam concentrate and compressed air simultaneously according to the mixing ratio requirements of the current type, so that the mixing ratio of each substance remains constant. This allows for continuous adjustment between the minimum and maximum range of the same type of foam, adapting to different fire scenarios.

[0008] In summary, it is necessary to propose an adaptive control method for on-board compressed air foam generating units. Summary of the Invention

[0009] The technical solution of this invention addresses the mainstream compressed air foam system equipped on fire trucks. To solve the problems of mutual interference between branches and insufficient adaptability of existing systems, it proposes an adaptive control method for on-board compressed air foam generating units.

[0010] To address the aforementioned technical problems, embodiments of the present invention provide an adaptive control method for vehicle-mounted compressed air foam generating units, the specific control flow of which is as follows:

[0011] S1 sends control signals for the opening degree of the water flow regulating valve and the type of foam through the control panel;

[0012] S2, the controller uses a signal conversion algorithm to convert the opening degree of the water flow regulating valve into an output signal, which is used to control the valve opening to reach the predetermined opening degree;

[0013] S3, the controller collects the water flow signal, calculates the current water flow through a linear calibration algorithm, and then calculates the required foam flow and compressed air flow based on the type of foam to be sprayed through a flow calculation algorithm.

[0014] S4. Based on the foam pump speed control algorithm, the speed of the foam pump is calculated, and the foam flow rate is controlled at the required flow rate.

[0015] S5, based on the compressed air flow control algorithm, controls the flow rate of compressed air by controlling the opening of the compressed air flow regulating valve, thereby controlling the flow rate at the required level;

[0016] S6. Then, according to the pressure balance method, the pressure of the branch water and the branch compressed air are adjusted to control the pressure difference between the branch water and the branch compressed air within a certain range.

[0017] Here, the water flow regulating valve opening control signal sent by the panel may be of two types: one is the unprocessed original signal and the other is the processed opening signal. For the unprocessed original signal, it is necessary to first convert the original signal into a valve opening signal before performing calculation, and the specific conversion method is as follows; for the processed opening signal, signal conversion is performed directly; the signal conversion algorithm converts the water flow regulating valve opening control signal sent by the panel into a signal capable of controlling the opening of the water flow regulating valve, so as to realize continuous adjustment of the opening of the water flow regulating valve from 0 to 100%.

[0018] Here, the flow calculation algorithm is used to calculate the required foam flow rate and compressed air flow rate, and the specific calculation formula is as follows:

[0019] Required foam flow rate q 泡沫 =k1q 水 , where k1 is the ratio of foam stock solution to water flow rate, q 水 is the water flow rate;

[0020] Required compressed air flow rate q 空气 =k2q 水 , where k2 is the ratio of compressed air to the water flow rate of the mixed liquid.

[0021] Here, the foam pump rotation speed control algorithm: first collect the signal of the foam stock solution flowmeter, obtain the current foam stock solution flow rate through the calibration algorithm, then calculate the expected rotation speed of the foam pump using the foam pump rotation speed control algorithm according to the current foam stock solution flow rate, and control the motor to move. The calculation formula of the foam pump rotation speed control algorithm is as follows: assume that each operation period is T, q n is the current foam flow rate, q n-1 is the previous foam flow rate, sq is the expected flow rate, and e is the error threshold; if sq-q n >e, the rotation speed N of the foam pump n = N n-1 +a / (kT), 0<k<1, a is the acceleration of the motor; if sq-q n <=e, the rotation speed N of the foam pump n = N n-1 +[(sq-q n ) / (q n -q n-1 )] *a / (kT).

[0022] Here, the compressed air flow rate control algorithm: first collect the signal of the compressed air flowmeter, obtain the current compressed air flow rate through the calibration algorithm, then calculate the expected opening signal of the compressed air flow regulating valve using the compressed air flow rate control algorithm according to the current compressed air flow rate, and control the opening size of the compressed air flow regulating valve; the calculation formula of the compressed air flow rate control algorithm is as follows: assume that each operation period is T1, q1n q1 represents the current compressed air flow rate. n-1 Let sq1 be the previous compressed air flow rate, sq1 be the desired compressed air flow rate, and e1 be the error threshold; if sq1-q1 n >e1, Expected compressed air flow signal v n = v n-1 +λ, where λ is the control signal step size of the compressed air flow regulating valve; if sq1-q1 n <= e1, expected compressed air flow rate signal v n =v n-1 +[(sq1-q1 n ) / (q1 n -q1 n-1 )]*λ.

[0023] The pressure balancing method employs a dual-threshold approach to control the pressure balance between the pre-mixing water and compressed air. The specific control process is as follows: 1) Acquire the water circuit pressure sensor signal to obtain the current water circuit pressure P_water. Determine if the water circuit pressure is within the desired pressure range [Pmin, Pmax]. If it is within this range, directly determine whether to perform pressure balancing adjustment. If it is not within this range, adjust the opening of the water circuit pressure regulating valve using a PID algorithm to adjust the water circuit pressure to between [Pmin, Pmax], and then determine whether to perform pressure balancing adjustment. 2) If the pressure balancing regulator flag REgulator_Flag = false, it indicates that no pressure balancing adjustment has been performed. Further determination is then made if |P_Flag| = false. 水 -P 气 |<=P 阈值 , where P 水 For the current pressure of the waterway, P 气 The pressure of compressed air, P 阈值 To enable the pressure balance regulator, REgulator_Flag is set to true, and then the compressed air pressure regulating valve is controlled according to the pressure balance algorithm; 3) If the pressure balance regulator flag REgulator_Flag = true, if |P 水 -P 气 |<=P 关闭 , where P 关闭 To set the pressure balance regulator's closing threshold, REgulator_Flag is set to false; otherwise, the pressure balance algorithm controls the compressed air pressure regulating valve.

[0024] The vehicle-mounted compressed air foam generating unit includes a controller module, a control panel module, a sensor module, and an execution module. The controller module is installed on the vehicle and electrically connected to the control panel module, the sensor module, and the execution module. It is used to collect data from the sensor module and instructions from the control panel module, and to control the execution module. The sensor module includes a compressed air branch flow meter, a compressed air branch pressure sensor, a water branch pressure sensor, a water branch flow meter, and a foam concentrate flow meter, all installed on the pipeline. The execution module includes a compressed air branch pressure regulating valve, a compressed air branch flow regulating valve, a water branch pressure regulating valve, a water branch flow regulating valve, and a foam concentrate pump, all installed on the pipeline.

[0025] Implementing the embodiments of the present invention has the following beneficial effects: The adaptive control method for vehicle-mounted compressed air foam generating units of the present invention has been optimized and upgraded in terms of hardware and control methods based on existing technical solutions. It can realize independent adjustment of each unit without interference, and can steplessly adjust the range when facing different types of foam fire extinguishing, thereby improving the stability, applicability and fire extinguishing efficiency of the system. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a flowchart of the adaptive control method for an on-board compressed air foam generating unit provided by the present invention;

[0028] Figure 2 This is the logic control diagram of the pressure balance control method provided by the present invention;

[0029] Figure 3 This is a schematic diagram of the vehicle-mounted compressed air foam generating unit provided by the present invention.

[0030] The diagram shows: 1. Upper structure controller; 2. Tilt sensor; 3. Weighing sensor; 4. Engine; 5. Engine controller; 6. First power take-off port; 7. Generator; 8. PE controller; 9. Power generation system controller; 10. Generator power take-off; 11. Second power take-off port; 12. Fog cannon fan controller; 13. DC high voltage fuse PDM; 14. Fog cannon fan motor; and 15. Vehicle driving system. Detailed Implementation

[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] Please see Figure 1 , Figure 1 This is a flowchart of the adaptive control method for an on-board compressed air foam generator unit provided by the present invention. The specific control flow is as follows:

[0033] S1 sends control signals for the opening degree of the water flow regulating valve and the type of foam through the control panel;

[0034] S2, the controller uses a signal conversion algorithm to convert the opening degree of the water flow regulating valve into an output signal, which is used to control the valve opening to reach the predetermined opening degree;

[0035] S3, the controller collects the water flow signal, calculates the current water flow through a linear calibration algorithm, and then calculates the required foam flow and compressed air flow based on the type of foam to be sprayed through a flow calculation algorithm.

[0036] S4. Based on the foam pump speed control algorithm, the speed of the foam pump is calculated, and the foam flow rate is controlled at the required flow rate.

[0037] S5, based on the compressed air flow control algorithm, controls the flow rate of compressed air by controlling the opening of the compressed air flow regulating valve, thereby controlling the flow rate to the required level.

[0038] S6. Then, according to the pressure balance method, the pressure of the branch water and the branch compressed air are adjusted to control the pressure difference between the branch water and the branch compressed air within a certain range.

[0039] The water flow regulating valve opening control signal sent by the panel can be of two types: an unprocessed raw signal and a processed opening signal. For the unprocessed raw signal, it needs to be converted into a valve opening signal first, and then the conversion is performed. The specific conversion method is as follows: for the processed opening signal, the signal conversion is performed directly. The signal conversion algorithm converts the water flow regulating valve opening control signal sent by the panel into a signal that can control the opening of the water flow regulating valve, so as to realize the continuous adjustment of the water flow regulating valve opening from 0-100%.

[0040] The flow calculation algorithm is used to calculate the required foam flow rate and compressed air flow rate. The specific calculation formula is as follows:

[0041] Required foam flow rate q 泡沫 =k1q水 , where k1 is the flow ratio of foam concentrate to water, q 水 is the water flow rate;

[0042] The required compressed air flow rate q 空气 =k2q 水 , where k2 is the flow ratio of compressed air to the mixed liquid water.

[0043] The foam flow control algorithm is used to control the rotational speed of the foam pump. First, the signal of the foam concentrate flow meter is collected, the current foam concentrate flow rate is obtained through a calibration algorithm, then according to the current foam concentrate flow rate, the expected rotational speed of the foam pump is calculated using the foam pump rotational speed control algorithm to control the movement of the motor. The calculation formula of the foam pump rotational speed control algorithm is as follows:

[0044] Assume that each operation period is T, q n is the current foam flow rate, q n-1 is the previous foam flow rate, sq is the expected flow rate, and e is the error threshold;

[0045] If sq-q n >e, the rotational speed N of the foam pump n = N n-1 +a / (kT), where 0<k<1, and a is the acceleration of the motor;

[0046] If sq-q n <=e, the rotational speed N of the foam pump n =N n-1 +[(sq-q n ) / (q n -q n-1 )] *a / (kT).

[0047] The compressed air flow control algorithm is used to control the flow rate of compressed air. First, the signal of the compressed air flow meter is collected, the current compressed air flow rate is obtained through a calibration algorithm, then according to the current compressed air flow rate, the expected opening signal of the compressed air flow regulating valve is calculated using the compressed air flow control algorithm to control the opening degree of the compressed air flow regulating valve;

[0048] The calculation formula of the compressed air flow control algorithm is as follows:

[0049] Assume that each operation period is T1, q1 n is the current compressed air flow rate, q1 n-1 is the previous compressed air flow rate, sq1 is the expected compressed air flow rate, and e1 is the error threshold;

[0050] If sq1-q1 n >e1, the expected compressed air flow signal v n = vn-1 +λ, where λ is the step size of the compressed air flow regulating valve control signal;

[0051] If sq1-q1 n <= e1 Expected compressed air flow rate signal v n =v n-1 +[(sq1-q1 n ) / (q1 n -q1 n-1 )]*λ.

[0052] Please see Figure 2 , Figure 2 This is the logic control diagram of the pressure balance control method provided by the present invention. The pressure balance method uses a dual threshold to control the pressure balance between the water pressure before mixing and the compressed air pressure. The specific control flow is as follows:

[0053] 1) Collect the water pressure sensor signal to obtain the current water pressure P. 水 The system determines whether the water pressure is within the desired range [Pmin, Pmax]. If it is within this range, it directly determines whether to perform pressure balancing adjustment. If it is not within this range, the system uses a PID algorithm to adjust the opening of the water pressure regulating valve to adjust the water pressure to between [Pmin, Pmax], and then determines whether to perform pressure balancing adjustment.

[0054] 2) If the pressure balance regulator flag REgulator_Flag = false, it means that no pressure balance adjustment has been performed. Further investigation is needed if |P 水 -P 气 |<=P 阈值 , where P 水 The current pressure of the waterway, P 气 The pressure of compressed air, P 阈值 Set the threshold for opening the pressure balance regulator, set REgulator_Flag to true, and then control the compressed air pressure regulating valve according to the pressure balance algorithm;

[0055] 3) If the pressure balance regulator flag REgulator_Flag=true, if |P 水 -P 气 |<=P 关闭 (where P) 关闭 (Set the pressure balance regulator to the closing threshold), REgulator_Flag is set to false; otherwise, the pressure balance algorithm controls the compressed air pressure regulating valve.

[0056] Please see Figure 3 , Figure 3This is a schematic diagram of the vehicle-mounted compressed air foam generating unit provided by the present invention. The vehicle-mounted compressed air foam generating unit includes: a controller module, a control panel module, a sensor module, and an execution module; the controller module is installed on the vehicle and electrically connected to the control panel module, sensor module, and execution module respectively, for collecting data from the sensor module and instructions from the control panel module, and controlling the execution module through an algorithm; the sensor module includes a compressed air branch flow meter, a compressed air branch pressure sensor, a water branch pressure sensor, a water branch flow meter, and a foam concentrate flow meter, etc., installed on the pipeline; the execution module includes a compressed air branch pressure regulating valve, a compressed air branch flow regulating valve, a water branch pressure regulating valve, a water branch flow regulating valve, and a foam concentrate pump, etc., installed on the pipeline.

[0057] The adaptive control method for vehicle-mounted compressed air foam generating units of the present invention can rationally select the foam type and extinguishing flow rate according to the needs of the fire extinguishing scenario. The system adjusts the flow rates of water, foam concentrate and compressed air in the unit according to the mixing ratio requirements of the current type based on the control command and adaptive control algorithm, so that the mixing ratio of each substance remains constant. This achieves continuous adjustment between the minimum and maximum range of the same type of foam to adapt to different fire scenarios. Moreover, each unit is independent and does not interfere with each other, which can improve the stability of the system and the fire extinguishing efficiency.

[0058] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An adaptive control method for an on-board compressed air foam generating unit, characterized in that, The control process for the vehicle-mounted compressed air foam generator unit is as follows: S1 sends control signals for the opening degree of the water flow regulating valve and the type of foam through the control panel; S2, the controller uses a signal conversion algorithm to convert the opening degree of the water flow regulating valve into an output signal, which is used to control the valve opening to reach the predetermined opening degree; S3, the controller collects the water flow signal, calculates the current water flow through a linear calibration algorithm, and then calculates the required foam flow and compressed air flow based on the type of foam to be sprayed through a flow calculation algorithm. S4. Based on the foam pump speed control algorithm, the speed of the foam pump is calculated, and the foam flow rate is controlled at the required flow rate. S5, according to the compressed air flow control algorithm, controls the flow rate of compressed air by controlling the opening of the compressed air flow regulating valve, thereby controlling the flow rate at the required level; S6. Then, according to the pressure balance method, the pressure difference between the branch water and the branch compressed air is controlled within a certain range by adjusting the pressure of the branch water and the branch compressed air. The foam pump speed control algorithm is as follows: First, the signal of the foam raw material flow meter is collected, and the current foam raw material flow rate is obtained through the calibration algorithm. Then, based on the current foam raw material flow rate, the desired speed of the foam pump is calculated using the foam pump speed control algorithm, and the motor movement is controlled. The calculation formula for the foam pump speed control algorithm is as follows: Assuming each operation cycle is T, q n For the current bubble flow, q n-1 sq is the previous foam flow rate, e is the error threshold, N is the actual speed of the foam pump, and a is the acceleration of the motor. If sq-q n >e, the speed N of the foam pump n = N n-1 +a / (kT), 0 <k<1; If sq-q n <= e, the speed N of the foam pump n = N n-1 +[ (sq-q n ) / (q n -q n-1 )] *a / (kT), 0 <k<1; The compressed air flow control algorithm is as follows: First, the compressed air flow meter signal is acquired, and the current compressed air flow is obtained through a calibration algorithm. Then, based on the current compressed air flow, the compressed air flow control algorithm is used to calculate the desired opening signal of the compressed air flow regulating valve and control the opening size of the compressed air flow regulating valve. The calculation formula for the compressed air flow control algorithm is as follows: Assume each calculation cycle is T1, q1 n q1 represents the current compressed air flow rate. n-1 sq1 is the previous compressed air flow rate, e1 is the expected compressed air flow rate, v is the actual compressed air flow rate signal, and λ is the step size of the compressed air flow rate regulating valve control signal. If sq1-q1 n >e1, Expected compressed air flow signal v n = v n-1 +λ; If sq1-q1 n <= e1, expected compressed air flow rate signal v n =v n-1 +[ (sq1-q1 n ) / (q1 n -q1 n-1 )]*λ; The pressure balancing method uses a dual threshold to control the pressure balance between the water pressure before mixing and the compressed air pressure. The specific control process is as follows: a. Collect the water pressure sensor signal to obtain the current water pressure P. 水 Determine if the water pressure is within the desired range [Pmin, Pmax]. If it is within this range, determine whether to perform pressure balancing adjustment. If it is not within this range, adjust the opening of the water pressure regulating valve using the PID algorithm to adjust the water pressure to between [Pmin, Pmax], and then determine whether to perform pressure balancing adjustment. b. If the pressure balance regulator flag REgulator_Flag = false, it means that no pressure balance adjustment has been performed. Further investigation is needed if |P 水 -P 气 |<=P 阈值 , where P 水 The current pressure of the waterway, P 气 The pressure of compressed air, P 阈值 Set the threshold for opening the pressure balance regulator, set REgulator_Flag to true, and then control the compressed air pressure regulating valve according to the pressure balance algorithm; If the pressure balance regulator flag REgulator_Flag=true, if |P 水 -P 气 |<=P 关闭 , where P 关闭 To set the pressure balance regulator's closing threshold, REgulator_Flag is set to false; otherwise, the pressure balance algorithm controls the compressed air pressure regulating valve.

2. The adaptive control method for an on-board compressed air foam generating unit according to claim 1, characterized in that, The water flow regulating valve opening control signal can be of two types: an unprocessed raw signal and a processed opening signal. For the unprocessed raw signal, it is necessary to first convert the raw signal into a valve opening signal and then perform calculation and conversion. For the processed opening signal, the signal conversion is performed directly. The signal conversion algorithm converts the water flow regulating valve opening control signal sent by the panel into a signal that can control the opening of the water flow regulating valve, so as to realize the continuous adjustment of the water flow regulating valve opening from 0-100%.

3. The adaptive control method for an on-board compressed air foam generating unit according to claim 1, characterized in that, The flow calculation algorithm is used to calculate the required foam flow rate and compressed air flow rate. The specific calculation formula is as follows: Required foam flow rate q 泡沫 =k1q 水 Where k1 is the ratio of foam concentrate to water flow rate, q 水 Water flow rate; Required compressed air flow rate q 空气 =k2q 水 , where k2 is the flow ratio of compressed air to water mixture.

4. The adaptive control method for an on-board compressed air foam generating unit according to claim 1, characterized in that, The vehicle-mounted compressed air foam generating unit includes a controller module, a control panel module, a sensing module, and an execution module. The controller module is installed on the vehicle and is electrically connected to the electrical components in the control panel module, sensing module, and execution module. It is used to collect data from the sensing module and instructions from the control panel module, and to control the actions of the execution module. The sensing module includes a compressed air branch flow meter, a compressed air branch pressure sensor, a water branch pressure sensor, a water branch flow meter, and a foam concentrate flow meter, all installed on the pipeline. The execution module includes a compressed air branch pressure regulating valve, a compressed air branch flow regulating valve, a water branch pressure regulating valve, a water branch flow regulating valve, and a foam concentrate pump, all installed on the pipeline.

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