An initiator ignition control and real-time self-checking circuit and method

Abstract

The present invention relates to the technical field of initiator ignition control, and provides an initiator ignition control and real-time self-checking circuit and method. The circuit includes a three-stage ignition switch main path, a control circuit, a switch detection circuit, and an initiator resistance real-time monitoring circuit. The three-stage ignition switch main path is composed of a first-stage PMOS manual switch, a second-stage PMOS single-chip microcomputer control switch, a third-stage NMOS single-chip microcomputer control switch, a current-limiting resistor, and an initiator connected in series in sequence. The control and switch detection circuit is used to detect the switch state of the three-stage ignition switch in real time. The initiator resistance real-time monitoring circuit inputs a weak current signal to the initiator through voltage source excitation at both ends of the initiator to realize the measurement of the initiator resistance and detect whether the initiator is connected. The circuit of the present invention is simple and reliable, which is beneficial to the miniaturization of the entire ignition circuit; it fully considers the possible misfiring under abnormal states such as the power-on reset of the single-chip microcomputer, the program running away, and the weak current excitation.

Description

Technical Field

[0001] The present invention relates to the technical field of initiator ignition control, and particularly to an initiator ignition control and real-time self-checking circuit and method. Background Art

[0002] A fixed-wing unmanned aerial vehicle (UAV) can achieve autonomous recovery by means of gliding descent or parachute landing. During parachute landing, actions such as opening the cabin, ejecting the parachute, and cutting the parachute are realized by the ignition of initiators, so as to achieve the recovery of the UAV. If the initiator fails, the ignition cable is open-circuited, or the ignition circuit fails, etc., it will directly affect whether the UAV can be recovered without failure. If it is detected in real time that there is a problem with the ignition system, the method of emergency gliding descent can effectively improve the survival rate of UAV recovery. Therefore, the requirements for the reliability design of the initiator ignition circuit, the real-time self-checking of initiators, and the real-time self-checking of the ignition circuit are getting higher and higher.

[0003] The more widely used one is the electrically initiated initiator, with a resistance of about 1 - 2 ohms, which is connected to the flight control computer through a cable. Its typical failure mode is the open circuit of the initiator bridge wire. To ensure the reliability of the recovery system, it is necessary to detect the resistance of the initiator in real time during the launch and recovery of the UAV to determine whether there is an open-circuit fault. To ensure the safety of the system, when designing the initiator control system, the safety of the initiator during testing and operation should be fully considered, especially the safety during testing and operation after the initiator is installed on the aircraft, so as to prevent the accidental explosion of the initiator. At the same time, it is also necessary to detect in real time whether the initiator control circuit is faulty and whether the initiator can fire reliably. To prevent the accidental explosion of the initiator, currently, most of the initiator ignition control circuits are connected in series with multiple relay switches, and the purpose of preventing misfiring is achieved by closing them step by step. The self-checking of each stage of the switch is mostly carried out in the ground test mode by sequentially opening each stage of the switch and judging the quality of the switch by measuring the circuit voltage after opening. The self-checking of the subsequent stage of the switch must be carried out when the previous stages of the switches are closed, and it is impossible to realize the independent self-checking of each stage of the switch. At the same time, this method is not suitable for real-time self-checking when the initiator is connected. Summary of the Invention

[0004] The purpose of the present invention is to overcome at least one of the deficiencies of the prior art, and provide an initiator ignition control and real-time self-checking circuit and method, which can realize the real-time detection of the resistance value of the initiator, and at the same time satisfy the real-time self-checking of the states of each stage of the switch when the initiator is connected, ensure that the ignition signal is not misoutput, the initiator is not accidentally exploded, the ignition drive current is strong, the structure is easy to implement, and meet the safe and reliable parachute landing recovery of the UAV.

[0005] The present invention adopts the following technical solutions:

[0006] On the one hand, the present invention provides an initiator ignition control and real-time self-checking circuit, including a three-stage ignition switch main path, an initiator resistance value real-time monitoring circuit, and a control and switch detection circuit;

[0007] The main path of the three - stage ignition switch includes a first - stage PMOS manual switch, a second - stage PMOS single - chip microcomputer control switch, a third - stage NMOS single - chip microcomputer control switch, a current - limiting resistor, and an initiator connected in series in sequence.

[0008] For the real - time monitoring circuit of the initiator resistance, a weak current signal is input to the initiator through a voltage - source excitation across the initiator, and the resistance of the initiator is calculated through an operational - amplifier circuit to achieve the measurement of the initiator resistance; meanwhile, whether the initiator is connected and whether it is ignited are detected.

[0009] The control and switch detection circuit is used to control the main path of the three - stage ignition switch and the real - time monitoring circuit of the initiator resistance, and to detect the on - off state of the three - stage ignition switch and the resistance - detection instruction switch of the initiator in real time.

[0010] In any of the above - mentioned possible implementation manners, a further implementation manner is provided. The control and switch detection circuit includes a single - chip microcomputer MCU, and the single - chip microcomputer MCU includes 4 I / O bidirectional ports and 1 A / D acquisition channel.

[0011] 3 of the I / O bidirectional ports are respectively connected to the three - stage ignition switch for signal connection to achieve the state detection of the three - stage ignition switch.

[0012] The remaining 1 I / O bidirectional port is connected to the resistance - detection instruction switch for signal connection, and the A / D acquisition channel is used to collect the resistance of the initiator; in the state where the first - stage MOS manual switch is closed, the state detection of the resistance - detection instruction switch of the initiator is achieved.

[0013] In any of the above - mentioned possible implementation manners, a further implementation manner is provided. The control and switch detection circuit further includes a first - stage ignition - switch detection circuit, a second - stage ignition - switch detection circuit, and a third - stage ignition - switch detection circuit.

[0014] The first - stage ignition - switch detection circuit detects the voltage of the resistor - capacitor network after the first - stage ignition switch through the opening and closing of a mechanical switch to achieve the self - detection of the state of the first - stage ignition switch.

[0015] The second - stage ignition - switch detection circuit detects the voltage after the second - stage ignition switch and the current - limiting resistor through the high and low levels of the I / O port of the single - chip microcomputer MCU to detect the on - off state of the second - stage ignition switch.

[0016] The third - stage ignition - switch detection circuit detects the on - off state of the third - stage ignition switch by sampling the drain voltage of the NMOS transistor.

[0017] For any of the possible implementation manners described above, a further implementation manner is provided. The excitation current in the initiating explosive device resistance real-time detection circuit is 10 mA, and the precise measurement of a 1-2 ohm resistor is realized through an instrumentation amplifier circuit and an operational amplifier.

[0018] For any of the possible implementation manners described above, a further implementation manner is provided. In the first-stage ignition switch detection circuit, the reliable opening of the first-stage ignition switch is realized by controlling the cathode of the diode to be grounded through a manual mechanical switch. The diode is used to effectively prevent the damage of high-voltage input or static electricity to the PMOS transistor.

[0019] For any of the possible implementation manners described above, a further implementation manner is provided. The second-stage ignition switch uses a PMOS switch, and the opening and closing of the PMOS switch are realized through the I / O port of the single-chip microcomputer MCU; the third-stage ignition switch uses an NMOS switch, and the opening and closing of the NMOS switch are realized through the I / O port of the single-chip microcomputer MCU.

[0020] For any of the possible implementation manners described above, a further implementation manner is provided. The reset state of the single-chip microcomputer MCU is a tri-state output, and the pull-down resistor is used to keep the level of the reset state at a low level; at the same time, in order to prevent all the I / Os from being set high or low in the runaway state of the single-chip microcomputer, different opening levels are set for the second-stage ignition switch and the third-stage ignition switch. The second-stage ignition switch is set to be in push-pull mode and is opened only when set high, and the third-stage ignition switch is set to be in OD mode and is opened only when set low.

[0021] On the other hand, the present invention also provides a method for initiating explosive device ignition control and real-time self-checking, which uses the above-mentioned initiating explosive device ignition control and real-time self-checking circuit. The method includes:

[0022] S1. First-stage ignition switch detection: By opening and closing the mechanical switch, the voltage of the resistor-capacitor network after the first-stage ignition switch is detected, and the status self-check of the first-stage ignition switch is realized by accessing the I / O port 1 of the single-chip microcomputer MCU; if the I / O port 1 is at a high voltage when the mechanical switch is grounded, it indicates that the first-stage ignition switch is in the open state; if the I / O port 1 is at a low voltage when the mechanical switch is disconnected from the ground, it indicates that the first-stage ignition switch is in the closed state, and the self-check of the first-stage ignition switch is normal.

[0023] S2. Second - stage ignition switch detection: Detect the voltage after the second - stage ignition switch and the current - limiting resistor through the high and low levels of the I / O port HG_CTR of the microcontroller MCU. The voltage after conditioning by the resistor - capacitor network and the operational amplifier is input to the microcontroller I / O port 2. If the I / O port 2 at the back end of the second - stage ignition switch is at a high voltage when the I / O port HG_CTR of the microcontroller is at a high level, it indicates that the second - stage ignition switch is in the open state. If the I / O port 2 at the back end of the second - stage ignition switch is at a low voltage when HG_CTR is at a low level, it indicates that the second - stage ignition switch is in the closed state, and the self - inspection of the second - stage ignition switch is normal.

[0024] S3. Third - stage ignition switch detection: Control the opening and closing of the third - stage ignition switch through the I / O2 port of the microcontroller MCU. When the I / O2 of the microcontroller MCU is at a low level, the triode is turned on, which simultaneously causes the NMOS transistor to conduct. When the I / O2 of the microcontroller MCU is at a high level, the triode is turned off, which simultaneously causes the third - stage ignition switch of the NMOS transistor to close. By detecting the voltage at the drain of the NMOS transistor, if it is at a high level, the third - stage ignition switch is turned on, and if it is at a low level, the third - stage ignition switch is turned off.

[0025] S4. Initiator resistance detection: The initiator is connected in series between the positive and negative terminals of the real - time monitoring circuit for the initiator resistance. A weak current signal is input to the initiator through a voltage source excitation across the initiator. When the initiator is connected, the first - stage voltage amplification is achieved through the instrumentation amplifier peripheral circuit, and the voltage second - stage amplification is achieved through the operational amplifier and input to the ADC input port 3 of the microcontroller MCU. Through the selection of the amplification factor, the precise measurement of a 1 - 2 ohm resistor is realized, thereby realizing the detection of whether the initiator is connected.

[0026] In any of the above - mentioned possible implementation manners, a further implementation manner is provided. In step S4, when the initiator is connected, it is necessary to turn off the second - stage ignition switch, turn on the third - stage ignition switch, and turn on the voltage source simultaneously to perform the resistance detection. If the third - stage ignition switch can be normally turned on, the resistance detection is normal. If the third - stage ignition switch cannot be normally turned on, the resistance detection shows zero ohms. Therefore, by performing high and low level operations on the I / O3 of the microcontroller MCU during the resistance detection, it is possible to detect whether the third - stage ignition switch is normal by detecting the initiator resistance.

[0027] The beneficial effects of the present invention are as follows:

[0028] 1. Compared with the traditional relay ignition switch control, an ignition switch control circuit based on the three - stage series connection of MOSFET (Metal - Oxide - Semiconductor Field - Effect Transistor) is proposed. The circuit is simple and reliable, which is conducive to the miniaturization of the entire ignition circuit.

[0029] 2. The present invention uses heterogeneous transistor switches, which can effectively avoid the probability of short - circuit faults in the same mode.

[0030] 3. By circuit design, the over-current capacity of the MOSFET and the current-limiting resistor are selected, which can greatly improve the circuit's drive current capacity and is especially suitable for insensitive initiators.

[0031] 4. The possible misfiring under abnormal conditions such as the power-on reset of the single-chip microcomputer, the program running wild, and the weak current excitation are fully considered.

[0032] 5. It can realize the real-time detection of the on-line resistance value of the initiator (including the airborne ignition cable).

[0033] 6. It can realize the real-time detection of the three-stage series switch of the MOSFET and the current-limiting resistor. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 The figure shows a schematic diagram of an initiator ignition control and real-time self-check circuit according to an embodiment of the present invention.

[0035] Figure 2 The figure shows a schematic diagram of the three-stage ignition switch path in the embodiment.

[0036] Figure 3 The figure shows a schematic diagram of the control circuit part in the control and switch detection circuit in the embodiment.

[0037] Figure 4 The figure shows a schematic diagram of the switch detection circuit part in the control and switch detection circuit in the embodiment.

[0038] Figure 5 The figure shows a schematic diagram of the real-time detection circuit of the initiator resistance value in the embodiment.

[0039] Figure 6 The figure shows a schematic diagram of the detection circuit of the first-stage PMOS manual switch of the three-stage ignition switch path in the embodiment.

[0040] Figure 7 The figure shows a schematic diagram of the detection circuit of the second-stage PMOS control switch of the three-stage ignition switch path in the embodiment.

[0041] Figure 8 The figure shows a schematic diagram of the detection circuit of the third-stage NMOS control switch of the three-stage ignition switch path in the embodiment. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0042] The following will describe the specific embodiments of the present invention in detail with reference to the specific drawings. It should be noted that the technical features described in the following embodiments or the combination of technical features should not be considered as isolated, and they can be combined with each other to achieve better technical effects. In the drawings of the following embodiments, the same reference numerals in each drawing represent the same features or components, which can be applied to different embodiments.

[0043] As shown Figure 1 in the figure, an ignition control and real-time self-checking circuit for initiating explosive devices according to an embodiment of the present invention includes a three-stage ignition switch main path, a real-time monitoring circuit for the resistance value of the initiating explosive device, and a control and switch detection circuit;

[0044] The three-stage ignition switch main path includes a first-stage PMOS manual switch, a second-stage PMOS single-chip microcomputer control switch, a third-stage NMOS single-chip microcomputer control switch, a current-limiting resistor, and the initiating explosive device connected in series in sequence. When the initiating explosive device is ignited, all three switches of the three-stage ignition switch path need to be opened simultaneously, as Figure 2 shown;

[0045] The real-time monitoring circuit for the resistance value of the initiating explosive device inputs a weak current signal to the initiating explosive device through voltage source excitation at both ends of the initiating explosive device, calculates the resistance value of the initiating explosive device through an operational amplifier circuit, and realizes the measurement of the resistance value of the initiating explosive device; meanwhile, it detects whether the initiating explosive device is connected and whether it is ignited;

[0046] The control and switch detection circuit is used to control the three-stage ignition switch main path and the real-time monitoring circuit for the resistance value of the initiating explosive device, and to detect the on or off state of the three-stage ignition switch and the resistance value detection instruction switch of the initiating explosive device in real time.

[0047] Preferably, the control and switch detection circuit includes a single-chip microcomputer MCU, and the single-chip microcomputer MCU includes 4 I / O bidirectional ports and 1 A / D acquisition channel;

[0048] 3 of the I / O bidirectional ports are respectively connected to the three-stage ignition switch for signal connection to realize the state detection of the three-stage ignition switch;

[0049] The remaining 1 I / O bidirectional port is connected to the resistance value detection instruction switch for signal connection, and the A / D acquisition channel is used to collect the resistance value of the initiating explosive device; when the first-stage MOS manual switch is in the off state, the state detection of the resistance value detection instruction switch of the initiating explosive device is realized.

[0050] Preferably, the control and switch detection circuit further includes a first-stage ignition switch detection circuit, a second-stage ignition switch detection circuit, and a third-stage ignition switch detection circuit;

[0051] The first-stage ignition switch detection circuit detects the voltage of the resistor-capacitor network after the first-stage ignition switch through the opening and closing of the mechanical switch to realize the self-check of the state of the first-stage ignition switch;

[0052] The second-stage ignition switch detection circuit detects the voltage after the second-stage ignition switch and the current-limiting resistor through the high and low levels of the I / O port of the single-chip microcomputer;

[0053] The third-stage ignition switch detection circuit detects the on / off state of the third-stage ignition switch by sampling the drain voltage of the NMOS transistor.

[0054] Further preferably, the first-stage ignition switch adopts a typical PMOS control circuit, and the reliable opening of the first-stage ignition switch is realized by manually controlling the cathode of the diode to be grounded through a mechanical switch. The diode can effectively prevent the damage of the PMOS transistor caused by high-voltage input or static electricity. The second-stage ignition switch adopts a PMOS switch, and the opening and closing of the PMOS switch are realized through the I / O port of the single-chip microcomputer. The third-stage ignition switch adopts an NMOS switch, and the opening and closing of the NMOS switch are realized through the I / O port of the single-chip microcomputer.

[0055] The function of the current-limiting resistor is to set the optimal ignition current according to the ignition drive current and input voltage of different initiators, and it can provide sufficient drive current capacity.

[0056] The I / O port of the single-chip microcomputer needs to fully consider the switch state during the reset state. The selected single-chip microcomputer in the present invention has a tri-state output in the reset state, and the level of the reset state is kept at a low level through a pull-down resistor. At the same time, in order to prevent all the I / Os from being set high or low in the case of the single-chip microcomputer running wild, different opening levels are set for the second-stage ignition switch and the third-stage ignition switch. The second-stage ignition switch is set to the push-pull mode and can only be opened when set high, and the third-stage ignition switch is set to the OD mode and can only be opened when set low. The above measures can effectively ensure that the initiator will not explode accidentally. The present invention provides a circuit composed of resistors, capacitors, NPN, PNP transistors, and zener diodes to achieve the above functions. At the same time, if isolation is required, the above functions can also be achieved through an optocoupler.

[0057] In a specific embodiment, as Figure 3 shown, the control circuit part in the control and switch detection circuit has a core of an MCU single-chip microcomputer, which is composed of 4 bidirectional I / O ports and 1 A / D acquisition channel. Figure 2 In ①, ②, and ③, the control of the three-stage ignition switch path circuit is realized, Figure 2 in ① and ④, the switch control for detecting the resistance value of the initiator is realized, Figure 2 and in ⑤, the real-time monitoring circuit for collecting the resistance value of the initiator is realized.

[0058] In a specific embodiment, as Figure 4 shown, in the switch detection circuit part of the control and switch detection circuit, the switch detection of the three-stage ignition switch path circuit is mainly realized by ①, ②, and ③ of the MCU single-chip microcomputer, and the state detection of the switch for detecting the resistance value of the initiator is realized by ① and ④.

[0059] In a specific embodiment, as Figure 5As shown, the real-time detection circuit of the initiating explosive device resistance value executes under the condition of "the first-level MOS manual switch of the three-level ignition switch path is in the off state". The control circuit turns on the resistance detection instruction switch, uses the voltage source to excite the weak current signal input to the initiating explosive device, calculates the resistance value of the initiating explosive device through the operational amplifier circuit, realizes the measurement of the resistance value of the initiating explosive device, and can also detect whether the initiating explosive device is connected and whether it is ignited.

[0060] Figure 1 It is the overall structure diagram of the initiating explosive device ignition control and real-time self-checking circuit. The control and switch detection circuit is the core part, and the three-level ignition switch path and the initiating explosive device real-time monitoring circuit are the execution circuits.

[0061] An embodiment of the present invention also provides a method for initiating explosive device ignition control and real-time self-checking, including:

[0062] S1. Detection of the first-level ignition switch: By opening and closing the mechanical switch, detect the voltage of the resistor-capacitor network after the first-level ignition switch, and realize the status self-check of the first-level ignition switch by connecting to the I / O port 1 of the single-chip microcomputer MCU; if the I / O port 1 is at a high voltage when the mechanical switch is grounded, it means that the first-level ignition switch is in the open state. If the I / O port 1 is at a low voltage when the mechanical switch is disconnected from the ground, it means that the first-level ignition switch is in the closed state, and the self-check of the first-level ignition switch is normal;

[0063] S2. Detection of the second-level ignition switch: By the high and low levels of the I / O port HG_CTR of the single-chip microcomputer MCU, detect the voltage after the second-level ignition switch and the current-limiting resistor, and input the voltage after conditioning by the resistor-capacitor network and the operational amplifier to the I / O port 2 of the single-chip microcomputer; if the I / O port 2 at the back end of the second-level ignition switch is at a high voltage when the I / O port HG_CTR of the single-chip microcomputer is at a high level, it means that the second-level ignition switch is in the open state. If the I / O port 2 at the back end of the second-level ignition switch is at a low voltage when HG_CTR is at a low level, it means that the second-level ignition switch is in the closed state, and the self-check of the second-level ignition switch is normal;

[0064] S3. Detection of the third-level ignition switch: Control the opening and closing of the third-level ignition switch through the I / O2 port of the single-chip microcomputer MCU. If the I / O2 of the single-chip microcomputer MCU is at a low level, the triode turns on, which simultaneously causes the NMOS transistor to conduct. If the I / O2 of the single-chip microcomputer MCU is at a high level, the triode turns off, which simultaneously causes the third-level ignition switch of the NMOS transistor to close; by detecting the drain voltage of the NMOS transistor, if it is at a high level, the third-level ignition switch is open, and if it is at a low level, the third-level ignition switch is closed;

[0065] S4. Initiator Resistance Detection: The initiator is connected in series between the positive and negative terminals of the real-time monitoring circuit for the initiator resistance; a weak current signal is input to the initiator through voltage source excitation across the initiator; when the initiator is connected, the first-stage voltage amplification is achieved through the instrumentation amplifier peripheral circuit, the second-stage voltage amplification is achieved through the operational amplifier and input to the ADC input port 3 of the microcontroller MCU, and the precise measurement of a 1 - 2 ohm resistor is achieved through the selection of the amplification factor, thereby realizing the detection of whether the initiator is connected.

[0066] In step S4, when the initiator is connected, the second-stage ignition switch needs to be closed, the third-stage ignition switch needs to be opened, and the voltage source needs to be opened simultaneously to perform the resistance detection; if the third-stage ignition switch can be opened normally, the resistance detection is normal, and if the third-stage ignition switch cannot be opened normally, the resistance detection shows zero ohms; therefore, by performing high and low level operations on the I / O3 of the microcontroller MCU during the resistance detection, it is possible to detect whether the third-stage ignition switch is normal by detecting the initiator resistance.

[0067] In a specific embodiment, as Figure 6 shown, the first-stage PMOS manual switch detection circuit for the three-stage ignition switch path: By opening and closing the mechanical switch K1, the voltage of the resistor-capacitor network formed by R1, R3, and C1 after the first-stage ignition switch is detected, and by connecting to the ADC input port 1 of the microcontroller, the self-check of the state of the first-stage ignition switch is realized. If the ADC input terminal is at a high voltage when K1 is grounded, it indicates that V1 is in the open state; if the ADC input terminal is at a low voltage when K1 is disconnected from the ground, it indicates that V1 is in the closed state, and the self-check of V1 is normal.

[0068] In a specific embodiment, as Figure 7 shown, the second-stage PMOS control switch detection circuit for the three-stage ignition switch path: By the high and low levels of the I / O port I / O1 of the microcontroller, the voltage after the second-stage ignition switch and the current-limiting resistor is detected, and the voltage conditioned by the resistor-capacitor network composed of R6, C2, and R7 and the operational amplifier U1 is input to the ADC port 2 of the microcontroller. If the ADC input voltage at the rear end of V4 is at a high voltage when the I / O port I / O1 of the microcontroller is at a high level, it indicates that V4 is in the open state; if the ADC input terminal at the rear end of V4 is at a low voltage when I / O1 is at a low level, it indicates that V4 is in the closed state, and the self-check of V4 is normal.

[0069] In a specific embodiment, as Figure 8As shown in the figure, the third-stage NMOS control switch detection circuit of the three-stage ignition switch path: The opening and closing of V7 are controlled by the I / O2 port of the single-chip microcomputer. When the I / O2 of the single-chip microcomputer is at a low level, the triode V8 turns on, which in turn causes the NMOS transistor V7 to conduct. When the I / O2 of the single-chip microcomputer is at a high level, the triode V8 turns off, which in turn causes the NMOS transistor V7 to turn off. By detecting the drain voltage of V7, if it is at a high level, V7 is on, and if it is at a low level, V7 is off.

[0070] In a specific embodiment, as Figure 8 shown in the figure, the real-time detection circuit diagram of the initiator resistance value: The initiator is connected in series between the positive and negative terminals of the real-time monitoring circuit of the initiator resistance value. A weak current signal is input to the initiator through a voltage source excitation across the initiator. In the present invention, the current is 10 mA. The on-off control of the voltage source is realized through R20, R22, the triode V12 and the I / O3 port of the single-chip microcomputer. The diode V11 serves to suppress the reverse current, and R19 is a current-limiting resistor, which can generate the 10 mA current excitation of the present invention. This excitation current can ensure that the initiator will not accidentally explode during the detection of the initiator resistance value. When the initiator is connected, the first-stage voltage amplification is realized through the typical U2 instrument amplification peripheral circuit, and the second-stage voltage amplification is realized through the U3 operational amplifier and input to the ADC input port 3 of the single-chip microcomputer. Through the selection of the amplification factor, the precise measurement of a 1-2 ohm resistor can be achieved, thereby realizing the detection of whether the initiator is connected and whether it is ignited.

[0071] A kind of initiator ignition control and real-time self-checking circuit and method of the present invention can detect the resistance value of the initiator and whether there is a fault in the switch in the ignition circuit, and fully consider the power-on and power-off reset of the controller. This circuit has the characteristics of high ignition reliability and easy implementation of the structure, and can be widely applied to the ignition control and self-checking of sensitive and insensitive initiators during the parachute recovery of fixed-wing unmanned aerial vehicles.

[0072] Although several embodiments of the present invention have been given in this article, those skilled in the art should understand that the embodiments in this article can be changed without departing from the spirit of the present invention. The above embodiments are only exemplary and should not be used as the limitation of the scope of the rights of the present invention.

Claims

1. An initiating explosive device ignition control and real-time self-checking circuit, characterized in that The circuit includes a three - stage ignition switch main path, a real - time monitoring circuit for the resistance of the initiator, and a control and switch detection circuit; The three - stage ignition switch main path includes a first - stage PMOS manual switch, a second - stage PMOS single - chip microcomputer control switch, a third - stage NMOS single - chip microcomputer control switch, a current - limiting resistor, and an initiator connected in series in sequence; In the real - time monitoring circuit for the resistance of the initiator, a weak current signal is input to the initiator through a voltage source excitation across the initiator, and the resistance of the initiator is calculated through an operational amplifier circuit to realize the measurement of the resistance of the initiator; meanwhile, whether the initiator is connected is detected; The control and switch detection circuit is used to control the three - stage ignition switch main path and the real - time monitoring circuit for the resistance of the initiator, and to detect the on - off state of the three - stage ignition switch and the resistance detection instruction switch of the initiator in real time; The control and switch detection circuit includes a single - chip microcomputer MCU, and the single - chip microcomputer MCU includes 4 I / O bidirectional ports and 1 A / D acquisition channel; 3 of the I / O bidirectional ports are respectively connected to the three - stage ignition switch for signal connection to realize the state detection of the three - stage ignition switch; The remaining 1 I / O bidirectional port is connected to the resistance detection instruction switch of the initiator, and the A / D acquisition channel is used to collect the resistance of the initiator; in the state where the first - stage MOS manual switch is closed, the state detection of the resistance detection instruction switch of the initiator is realized; The control and switch detection circuit also includes a first - stage ignition switch detection circuit, a second - stage ignition switch detection circuit, and a third - stage ignition switch detection circuit; The first - stage ignition switch detection circuit detects the voltage of the resistor - capacitor network after the first - stage ignition switch through the opening and closing of a mechanical switch to realize the self - detection of the state of the first - stage ignition switch; The second - stage ignition switch detection circuit detects the voltage after the second - stage ignition switch and the current - limiting resistor through the high and low levels of the I / O port of the single - chip microcomputer MCU to detect the on - off state of the second - stage ignition switch; The third - stage ignition switch detection circuit detects the on - off state of the third - stage ignition switch by sampling the drain voltage of the NMOS transistor.

2. The initiating explosive device ignition control and real-time self-checking circuit according to claim 1, characterized in that, The excitation current in the real - time detection circuit for the resistance of the initiator is 10 mA, and the precise measurement of a 1 - 2 ohm resistor is realized through an instrumentation amplifier circuit and an operational amplifier.

3. The initiator ignition control and real-time self-checking circuit according to claim 1, characterized in that, The first - stage ignition switch detection circuit controls the cathode of the diode to be grounded through a manual mechanical switch to realize the reliable opening of the first - stage ignition switch, and the diode is used to effectively prevent the damage of high - voltage input or static electricity to the PMOS transistor.

4. The initiator ignition control and real-time self-checking circuit according to claim 1, characterized in that, The second - stage ignition switch uses a PMOS switch, and the opening and closing of the PMOS switch are realized through the I / O port of the single - chip microcomputer MCU; the third - stage ignition switch uses an NMOS switch, and the opening and closing of the NMOS switch are realized through the I / O port of the single - chip microcomputer MCU.

5. The initiator ignition control and real-time self-checking circuit according to claim 3, characterized in that, The reset state of the single-chip microcomputer MCU is a tri-state output, and the level of the reset state is maintained at a low level through a pull-down resistor. At the same time, in order to prevent all I / Os from being set high or low in the case of the single-chip microcomputer running wild, different opening levels are set for the second-stage ignition switch and the third-stage ignition switch. The second-stage ignition switch is set to be in push-pull mode and only turns on when set high, and the third-stage ignition switch is set to be in OD mode and only turns on when set low.

6. A method for initiating explosive device ignition control and real-time self-check, characterized in that, The method uses a pyrotechnic ignition control and real-time self-checking circuit as described in any one of claims 1-5. The method includes: S1. Detection of the first-stage ignition switch: By opening and closing the mechanical switch, the voltage of the resistor-capacitor network after the first-stage ignition switch is detected. By accessing the I / O port 1 of the single-chip microcomputer MCU, the status self-check of the first-stage ignition switch is realized. If the I / O port 1 is at a high voltage when the mechanical switch is grounded, it means that the first-stage ignition switch is in the open state. If the I / O port 1 is at a low voltage when the mechanical switch is disconnected from the ground, it means that the first-stage ignition switch is in the closed state, and the self-check of the first-stage ignition switch is normal. S2. Detection of the second-stage ignition switch: By the high and low levels of the I / O port HG_CTR of the single-chip microcomputer MCU, the voltage after the second-stage ignition switch and the current-limiting resistor is detected. The voltage conditioned by the resistor-capacitor network and the operational amplifier is input to the I / O port 2 of the single-chip microcomputer. If the I / O port 2 at the back end of the second-stage ignition switch is at a high voltage when the I / O port HG_CTR of the single-chip microcomputer is at a high level, it means that the second-stage ignition switch is in the open state. If the I / O port 2 at the back end of the second-stage ignition switch is at a low voltage when HG_CTR is at a low level, it means that the second-stage ignition switch is in the closed state, and the self-check of the second-stage ignition switch is normal. S3. Detection of the third-stage ignition switch: The opening and closing of the third-stage ignition switch are controlled by the I / O2 port of the single-chip microcomputer MCU. If the I / O2 of the single-chip microcomputer MCU is at a low level, the triode turns on, which in turn causes the NMOS transistor to conduct. If the I / O2 of the single-chip microcomputer MCU is at a high level, the triode disconnects, which in turn causes the third-stage ignition switch of the NMOS transistor to close. By detecting the drain voltage of the NMOS transistor, if it is at a high level, the third-stage ignition switch is on, and if it is at a low level, the third-stage ignition switch is off. S4. Detection of the resistance value of the pyrotechnic device: The pyrotechnic device is connected in series between the positive and negative terminals of the pyrotechnic device resistance real-time monitoring circuit. A weak current signal is input to the pyrotechnic device through a voltage source excitation across the pyrotechnic device. When the pyrotechnic device is connected, the first-stage voltage amplification is realized through the instrumentation amplifier peripheral circuit, the voltage second-stage amplification is realized through the operational amplifier and input to the ADC input port 3 of the single-chip microcomputer MCU. The accurate measurement of a 1-2 ohm resistor is realized through the selection of the amplification factor, and then the detection of whether the pyrotechnic device is connected is realized.

7. The initiator ignition control and real-time self-checking method according to claim 6, characterized in that, In step S4, when the pyrotechnic device is hooked up, the second-stage ignition switch needs to be turned off, the third-stage ignition switch needs to be turned on, and the voltage source needs to be turned on simultaneously to perform the resistance detection; if the third-stage ignition switch can be normally turned on, the resistance detection is normal, and if the third-stage ignition switch cannot be normally turned on, the resistance detection shows zero ohms; when the resistance detection is passed, the high and low level operations are performed on the I / O3 of the microcontroller MCU, and whether the third-stage ignition switch is normal can be detected by detecting the resistance of the pyrotechnic device.

Images