A signal detection circuit for an actuator limit switch

Abstract

This invention relates to the field of aviation equipment circuit signal detection technology, specifically to a signal detection circuit for actuator cylinder limit switches. It is powered by a power socket switch module connected to the power grid. By setting up independent first voltage conversion module, extended end limit switch detection module, second voltage conversion module, and retracted end limit switch detection module, it enables simultaneous power-on detection of the on / off signals of the extended and retracted end limit switches of the actuator cylinder. Based on the signal feedback from the limit switches, it determines whether the landing gear is retracted / extended, improving work efficiency, realizing on / off detection of each circuit, and increasing the reliability of the detection results.

Description

Technical Field

[0001] This invention relates to the field of circuit signal detection technology for aviation equipment, and more specifically, to a signal detection circuit for an actuator limit switch. Background Technology

[0002] In the aviation field, the retraction and extension of aircraft landing gear, wheel well covers, flaps, speed brakes, and nozzles are all achieved through actuators. Limit switches are installed at both the extended and retracted ends of the actuators. When the aircraft issues a lowering command, the actuator system supplies hydraulic fluid to the extension nozzle of the actuator, causing the piston rod to extend the actuator. When the actuator reaches a specific position, it triggers a lever to press the limit switch, changing the switch's contact state and sending a lowering signal indicating that the actuator is in the lowered position. When the aircraft issues an extension command, the actuator system supplies hydraulic fluid to the retraction nozzle of the actuator, causing the piston rod to retract. When the actuator retracts to a specific position, it triggers a lever to press the limit switch, changing the switch's contact state and sending an extension signal indicating that the actuator is in the retracted position.

[0003] During the installation, commissioning, and reliability testing of the actuator cylinder, it is necessary to check whether the limit switch signals at both ends of the actuator cylinder are properly connected and disconnected. The internal signal wire of the socket connector of the double-redundant limit switch at the retraction end of the actuator cylinder has six pins, and the redundant limit switch has even more pins, numbered 1-2-3-4-5-6 in sequence. When 1-2 is connected, 1-3 is disconnected, and when 4-5 is connected and 4-6 is disconnected, it indicates that the piston rod is in the retracted position, displaying a retracted position signal. The existing detection circuit is as follows: Figure 1 The circuit shown is a temporary connection consisting of an excitation power supply, a multimeter, an adapter, and connecting wires. During measurement, the multimeter is used to simultaneously test the continuity of several signals. This method is difficult to use, as it requires ensuring a one-to-one correspondence between the pin numbers and the test channel numbers. The reliability of the test results is low. For example, it is used to check the continuity of high and low temperature test samples when they are taken out of the test chamber and the temperature cannot be maintained at a constant temperature. In addition, the measurement efficiency of the connection circuit is low. Summary of the Invention

[0004] This invention addresses the problems of high detection difficulty and low reliability of existing limit switch on / off signal detection circuits by proposing a signal detection circuit for actuator limit switches. It utilizes a power socket switch module connected to the power grid for power supply. By incorporating independent first voltage conversion module, extended end limit switch detection module, second voltage conversion module, and retracted end limit switch detection module, it enables simultaneous power-on detection of the on / off signals of the extended and retracted end limit switches of the actuator. Based on the signal feedback from the limit switches, it determines whether the landing gear is extended / retracted, improving work efficiency, achieving on / off detection for each circuit, and increasing the reliability of the detection results.

[0005] The specific implementation details of this invention are as follows:

[0006] A signal detection circuit for an actuator limit switch includes a power socket switch module, a first voltage conversion module, an extended end limit switch detection module, a second voltage conversion module, and a retracted end limit switch detection module.

[0007] The power socket switch module receives AC mains power at its input terminal and its output terminal is connected to the input terminal of the extended end limit switch detection module via a first voltage conversion module and to the input terminal of the retracted end limit switch detection module via a second voltage conversion module.

[0008] The output terminal of the extended end limit switch outputs an on / off signal for the extended end limit switch;

[0009] The output terminal of the retractable end limit switch outputs a retractable end limit switch on / off signal;

[0010] The power socket switch module is used to supply power after being connected to the power grid;

[0011] The first voltage conversion module is used to convert AC power into a first voltage signal;

[0012] The second voltage conversion module is used to convert AC mains power into a second voltage signal;

[0013] The extension end limit switch detection module is used to generate an extension end limit switch on / off signal based on the first voltage signal, and to determine whether the landing gear is retracted / lowered based on the extension end limit switch on / off signal.

[0014] The retractable end limit switch detection module is used to generate a retractable end limit switch on / off signal based on the second voltage signal, and to determine whether the landing gear is retracted / lowered based on the retractable end limit switch on / off signal.

[0015] To better realize the present invention, the signal detection circuit of the actuator limit switch further includes a first voltage and current meter and a second voltage and current meter;

[0016] The first voltage and current meter is positioned between the first voltage conversion module and the extended end limit switch detection module;

[0017] The second voltage and current meter is positioned between the second voltage conversion module and the retractable end limit switch detection module;

[0018] The first voltage and current meter is used to detect the contact quality of the extended end limit switch contacts based on the acquired first current and voltage change signal;

[0019] The second voltage and current meter is used to detect the contact quality of the retractable limit switch contacts based on the acquired second current and voltage change signal.

[0020] To better realize the present invention, the power switch socket module further includes a socket J1, a resistor R0, and a light-emitting diode power indicator D1;

[0021] One end of the resistor R0 is connected to the first output terminal of the socket J1, the first input terminal of the first voltage conversion module, and the first input terminal of the second voltage conversion module; the other end of the resistor R0 is connected to the input terminal of the LED power indicator D0.

[0022] The output terminal of the LED power indicator D0 is connected to the second output terminal of the socket J1, the second input terminal of the first voltage conversion module, and the second input terminal of the second voltage conversion module.

[0023] The socket J1 receives AC power at its input terminal and its third output terminal is connected to the third input terminal of the first voltage conversion module and the third input terminal of the second voltage conversion module.

[0024] To better realize the present invention, the first voltage conversion module further includes a first voltage conversion chip U1, a switch K1, a resistor R1, and a light-emitting diode D1;

[0025] The input terminal of the first voltage conversion chip is connected to the output terminal of the power switch socket module, the first output terminal of the first voltage conversion chip is connected to switch K1, the second output terminal of the first voltage conversion chip is connected to the output terminal of light-emitting diode D1, and the third output terminal of the first voltage conversion chip is connected to ground.

[0026] One end of the resistor R1 is connected to the input terminal of the switch K1 and the extended end limit switch detection module, and the other end is connected to the input terminal of the light-emitting diode D1.

[0027] The output terminal of the light-emitting diode D1 is connected to the input terminal of the extended end limit switch detection module;

[0028] The first voltage conversion chip is used to convert AC mains signal into 15V DC signal.

[0029] To better realize the present invention, the second voltage conversion module further includes a second voltage conversion chip U2, a switch K2, a resistor R2, and a light-emitting diode D2;

[0030] The input terminal of the second voltage conversion chip is connected to the output terminal of the power switch socket module, the first output terminal of the second voltage conversion chip is connected to switch K2, the second output terminal of the second voltage conversion chip is connected to the output terminal of light-emitting diode D2, and the third output terminal of the second voltage conversion chip is connected to ground.

[0031] One end of the resistor R2 is connected to the input terminal of the switch K2 and the retracted end limit switch detection module, and the other end is connected to the input terminal of the light-emitting diode D2.

[0032] The output terminal of the light-emitting diode D2 is connected to the input terminal of the retraction end limit switch detection module;

[0033] The second voltage conversion chip is used to convert AC mains signals into 28V DC signals.

[0034] To better realize the present invention, the extended end limit switch detection module further includes switch K3, switch K4, switch K5, a first electrical connector, and an extended end indicator unit;

[0035] The input terminal of the switch K3 is connected to the first voltage and current meter via the first electrical connector, and the output terminal of the switch K3 is connected to the input terminal of the protruding end indicator unit via the first electrical connector.

[0036] The input terminal of the switch K4 is connected to the first voltage and current meter via the first electrical connector, and the output terminal of the switch K4 is connected to the input terminal of the protruding end indicator unit via the first electrical connector.

[0037] The input terminal of switch K5 is connected to the first voltage and current meter via the first electrical connector, and the output terminal of switch K5 is connected to the input terminal of the protrusion end indicator unit via the first electrical connector.

[0038] The output terminal of the protruding end indicator unit is connected to the first voltage and current meter.

[0039] To better realize the present invention, the extended end indicator unit further includes multiple resistors R3 and red light-emitting diodes D3 connected in parallel;

[0040] The input terminals of multiple resistors R3 are connected to the output terminals of switches K3, K4, and K5 through the first electrical connector, and the output terminals of multiple resistors R3 are connected to the red light-emitting diode D3.

[0041] Multiple red LEDs D3 are connected to a first voltage and current meter.

[0042] To better realize the present invention, the retraction end limit switch detection module further includes switch K6, switch K7, second electrical connector, and retraction end indicator unit;

[0043] The input terminal of switch K6 is connected to the second voltage and current meter via the second electrical connector, and the output terminal of switch K6 is connected to the input terminal of the retraction end indicator unit via the second electrical connector.

[0044] The input terminal of switch K7 is connected to the second voltage and current meter via the second electrical connector, and the output terminal of switch K7 is connected to the input terminal of the retraction end indicator unit via the second electrical connector.

[0045] The output terminal of the retractable end indicator unit is connected to the second voltage and current meter.

[0046] To better realize the present invention, the retraction end indicator unit further includes multiple resistors R4 and green light-emitting diodes D4 connected in parallel;

[0047] The input terminals of multiple resistors R4 are connected to the output terminals of switches K6 and K7 via a second electrical connector, and the output terminals of multiple resistors R4 are connected to a green light-emitting diode D4.

[0048] Multiple green light-emitting diodes D4 are connected to a second voltage and current meter.

[0049] The present invention has the following beneficial effects:

[0050] This invention, by setting up two independent step-down transformer systems, can simultaneously power on and detect the on / off signals of the limit switches at the extended and retracted ends of the actuator cylinder, resulting in high working efficiency and good economy. The circuit of this invention also has the function of detecting the contact quality of the limit switches, improving the reliability of the detection quality. By changing the pin definition of the electrical connector, it can be used to detect the on / off signals of different types of products, which has the characteristics of good versatility. Attached Figure Description

[0051] Figure 1 This is a circuit diagram for detecting the limit switch signal of an existing actuator.

[0052] Figure 2 The schematic diagram of the signal detection circuit for the actuator limit switch provided by the present invention is shown.

[0053] Figure 3 The circuit schematic provided for this invention.

[0054] Figure 4 The schematic diagram of the circuit for the limit switch in the unpressed state provided in the embodiment of the present invention.

[0055] Figure 5 The schematic diagram of the circuit for the pressed state of the limit switch provided in the embodiment of the present invention.

[0056] Figure 6The schematic diagram of the circuit for the limit switch in the unpressed state provided in the embodiment of the present invention.

[0057] Figure 7 The schematic diagram of the circuit for the pressed state of the limit switch provided in the embodiment of the present invention. Detailed Implementation

[0058] To more clearly illustrate the technical solutions of the embodiments of the present invention, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. It should be understood that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments, and therefore should not be regarded as a limitation on the scope of protection. 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.

[0059] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "set up," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0060] Example 1:

[0061] This embodiment proposes a signal detection circuit for an actuator limit switch, such as... Figure 2 As shown, it includes a power socket switch module, a first voltage conversion module, an extended end limit switch detection module, a second voltage conversion module, and a retracted end limit switch detection module;

[0062] The power socket switch module receives AC mains power at its input terminal and its output terminal is connected to the input terminal of the extended end limit switch detection module via a first voltage conversion module and to the input terminal of the retracted end limit switch detection module via a second voltage conversion module.

[0063] The output terminal of the extended end limit switch outputs an on / off signal for the extended end limit switch;

[0064] The output terminal of the retractable end limit switch outputs a retractable end limit switch on / off signal;

[0065] The power socket switch module is used to supply power after being connected to the power grid;

[0066] The first voltage conversion module is used to convert AC power into a first voltage signal;

[0067] The second voltage conversion module is used to convert AC mains power into a second voltage signal;

[0068] The extension end limit switch detection module is used to generate an extension end limit switch on / off signal based on the first voltage signal, and to determine whether the landing gear is retracted / lowered based on the extension end limit switch on / off signal.

[0069] The retractable end limit switch detection module is used to generate a retractable end limit switch on / off signal based on the second voltage signal, and to determine whether the landing gear is retracted / lowered based on the retractable end limit switch on / off signal.

[0070] Working principle: This embodiment is powered by connecting to the power grid through a power socket switch module; by setting up independent first voltage conversion module, extended end limit switch detection module, second voltage conversion module, and retracted end limit switch detection module, it can simultaneously detect the on / off signals of the extended and retracted end limit switches of the actuator cylinder. Based on the signal feedback from the limit switches, it can determine whether the landing gear is retracted or extended, which improves work efficiency, realizes the on / off detection of each circuit, and increases the reliability of the detection results.

[0071] Example 2:

[0072] This embodiment is based on the above embodiment 1, such as... Figure 3 As shown, the signal detection circuit of the actuator limit switch further includes a first voltage and current meter and a second voltage and current meter;

[0073] The first voltage and current meter is positioned between the first voltage conversion module and the extended end limit switch detection module;

[0074] The second voltage and current meter is positioned between the second voltage conversion module and the retractable end limit switch detection module;

[0075] The first voltage and current meter is used to detect the contact quality of the extended end limit switch contacts based on the acquired first current and voltage change signal;

[0076] The second voltage and current meter is used to detect the contact quality of the retractable limit switch contacts based on the acquired second current and voltage change signal.

[0077] Working principle: In this embodiment, a voltmeter and an ammeter are used to detect the contact quality of the contacts after the state of the limit switch changes. One end of the ammeter is connected between the switch and the current-limiting resistor, and the other end is split into two paths and connected to the two pin terminals of the electrical connector respectively. The voltmeter is connected in parallel between the electrical connector and the two ends of the LED.

[0078] The other parts of this embodiment are the same as those in Embodiment 1 above, so they will not be described again.

[0079] Example 3:

[0080] This embodiment is based on any one of Embodiments 1-2 above, such as Figure 3 As shown, the power switch socket module includes socket J1, resistor R0, and LED power indicator D1;

[0081] One end of the resistor R0 is connected to the first output terminal of the socket J1, the first input terminal of the first voltage conversion module, and the first input terminal of the second voltage conversion module; the other end of the resistor R0 is connected to the input terminal of the LED power indicator D0.

[0082] The output terminal of the LED power indicator D0 is connected to the second output terminal of the socket J1, the second input terminal of the first voltage conversion module, and the second input terminal of the second voltage conversion module.

[0083] The socket J1 receives AC power at its input terminal and its third output terminal is connected to the third input terminal of the first voltage conversion module and the third input terminal of the second voltage conversion module.

[0084] Working principle: In this embodiment, after the power socket switch module is connected to the power grid via a three-prong plug and wires, the current passes through the 500Ω current-limiting resistor R0 to light up the LED D0 power indicator, thus sending a power-on signal.

[0085] The other parts of this embodiment are the same as any one of the above embodiments 1-2, so they will not be described again.

[0086] Example 4:

[0087] This embodiment is based on any one of embodiments 1-3 above, such as Figure 3 As shown, the first voltage conversion module includes a first voltage conversion chip U1, a switch K1, a resistor R1, and a light-emitting diode D1;

[0088] The input terminal of the first voltage conversion chip is connected to the output terminal of the power switch socket module, the first output terminal of the first voltage conversion chip is connected to switch K1, the second output terminal of the first voltage conversion chip is connected to the output terminal of light-emitting diode D1, and the third output terminal of the first voltage conversion chip is connected to ground.

[0089] One end of the resistor R1 is connected to the input terminal of the switch K1 and the extended end limit switch detection module, and the other end is connected to the input terminal of the light-emitting diode D1.

[0090] The output terminal of the light-emitting diode D1 is connected to the input terminal of the extended end limit switch detection module;

[0091] The first voltage conversion chip is used to convert AC mains signal into 15V DC signal.

[0092] The second voltage conversion module includes a second voltage conversion chip U2, a switch K2, a resistor R2, and a light-emitting diode D2;

[0093] The input terminal of the second voltage conversion chip is connected to the output terminal of the power switch socket module, the first output terminal of the second voltage conversion chip is connected to switch K2, the second output terminal of the second voltage conversion chip is connected to the output terminal of light-emitting diode D2, and the third output terminal of the second voltage conversion chip is connected to ground.

[0094] One end of the resistor R2 is connected to the input terminal of the switch K2 and the retracted end limit switch detection module, and the other end is connected to the input terminal of the light-emitting diode D2.

[0095] The output terminal of the light-emitting diode D2 is connected to the input terminal of the retraction end limit switch detection module;

[0096] The second voltage conversion chip is used to convert AC mains signals into 28V DC signals.

[0097] Working principle: In this embodiment, a closed loop is formed by connecting the first voltage conversion module, switch K1, current limiting resistor R1 and light-emitting diode D1 in series. The current limiting resistor R1 is used to control the current through the light-emitting diode.

[0098] The first voltage conversion module is connected to 220V AC power at its input terminal. After internal transformation and step-down processing, it outputs the DC28V rated operating voltage required by the limit switch at the retraction end of the actuator.

[0099] The input terminal of the second voltage conversion module is connected to the power switch, and the output terminal is connected to the limit switch at the extension end of the actuator via an electrical connector. Its function is to convert 220V AC power to 28V DC power.

[0100] The second voltage conversion module is connected to 220V AC power at its input terminal. After internal transformation and step-down processing, it outputs the DC28V rated operating voltage required by the limit switch at the extension end of the actuator.

[0101] The second voltage conversion module, switch K2, current limiting resistor R2, and light-emitting diode D2 are connected in series to form a closed loop. The current limiting resistor R2 is used to control the current through the light-emitting diode.

[0102] When switch K is pressed, the high-potential current passes through the ammeter and then branches through the electrical connector to the corresponding contact of the limit switch. After being current-limited by the resistor, the LED lights up and returns to the low potential. If the LED flickers in this circuit, it indicates that the limit switch circuit contact is not making good contact.

[0103] The other parts of this embodiment are the same as any one of the embodiments 1-3 above, so they will not be described again.

[0104] Example 5:

[0105] This embodiment is based on any one of embodiments 1-4 above, such as Figure 4 , Figure 5 As shown, the retraction end limit switch detection module includes switch K6, switch K7, a second electrical connector, and a retraction end indicator unit;

[0106] The input terminal of switch K6 is connected to the second voltage and current meter via the second electrical connector, and the output terminal of switch K6 is connected to the input terminal of the retraction end indicator unit via the second electrical connector.

[0107] The input terminal of switch K7 is connected to the second voltage and current meter via the second electrical connector, and the output terminal of switch K7 is connected to the input terminal of the retraction end indicator unit via the second electrical connector.

[0108] The output terminal of the retractable end indicator unit is connected to the second voltage and current meter.

[0109] The retraction end indicator unit includes multiple resistors R4 connected in parallel and a green light-emitting diode D4;

[0110] The input terminals of multiple resistors R4 are connected to the output terminals of switches K6 and K7 via a second electrical connector, and the output terminals of multiple resistors R4 are connected to a green light-emitting diode D4.

[0111] Multiple red LEDs D4 are connected to a second voltage and current meter.

[0112] Working Principle: The main criterion for determining whether the actuator has retracted / extended properly is the signal feedback from the limit switch. This is also the standard by which pilots judge whether the landing gear has retracted / extended. Therefore, in the circuit design, two independent limit switch detection systems are designed for the actuator retraction and extension ends. The number of detection signals is determined based on the type of limit switch used at both ends of the actuator retraction / extension. In the circuit of this embodiment, a dual-redundant limit switch is used at the actuator retraction end (see Table 1). The corresponding circuit design includes two on signals and two off signals (see Table 1). Figure 4 and Figure 5 The actuator extension end uses a triple-redundant limit switch (see Table 3). The corresponding circuit design consists of three on signals and three off signals (see Table 3). Figure 6 and Figure 7During signal detection, it is necessary to accurately determine whether the internal mechanical lock of the actuator is open / locked, and whether all the signals for opening / locking are provided. If not, it is necessary to determine which specific circuit is faulty to facilitate quick troubleshooting. To address these characteristics, the circuit of this invention uses LEDs in each pin circuit to detect the open / lock signals. The circuit design also ensures that each LED operates independently without interference, thereby detecting the continuity of each circuit.

[0113] The circuit design uses LEDs as signal indicators, with a red LED for power and blue LEDs for signal indicators. Current is limited by series resistors to prevent breakdown. The resistance R of the current-limiting resistors can be calculated using Ohm's law.

[0114]

[0115] Where R is the resistance of the current-limiting resistor, V is the power supply voltage, VF is the forward voltage drop of the diode element in the circuit, which is generally 3V, and I is the current to be controlled, which is generally 5 to 10mA.

[0116] The limit switch that comes with the actuator has a full stroke of only 4 to 6 mm. In order to detect the contact quality of the limit switch contacts, an ammeter and voltmeter are also designed into the circuit. The quality of the limit switch signal output can be determined by the changes in current and voltage.

[0117] Before the power is turned on, both push-button switches K1 and K2 are in the off state, and the detection circuit is a non-closed loop. After the power is turned on, press the push-button switches K1 and K2 to activate the detection circuit. Simultaneously, current flowing through the current-limiting resistor generates a positive voltage drop, illuminating the red LED. When the piston rod is not extended, observe the status of the blue LED in the piston rod retraction detection circuit. If blue LEDs 1-2 and 4-5 are lit, the piston rod retraction limit switch is functioning correctly; otherwise, it is faulty. Observe the status of the blue LED in the piston rod extension detection circuit. If blue LEDs 1-2, 4-5, and 9-8 are lit, the piston rod extension limit switch is functioning correctly; otherwise, it is faulty. If none of the blue LEDs are lit, observe the voltmeter and ammeter readings. If only the voltmeter reading is present, the limit switch is faulty; if the ammeter reading is significantly lower than normal, the limit switch has a poor contact fault. If a blue LED is flashing intermittently, its position in the circuit can be used to determine which signal is problematic.

[0118] like Figures 6-7Table 1 shows the schematic diagram of the circuit used in this embodiment to detect the limit switch signal at the retracted end of the actuator piston rod. The electrical connector serves as the connection carrier for converting the aviation plug and socket. Wiring is performed according to the pin definitions in Table 1. In the free state of the limit switch at the retracted end of the actuator piston rod, the internal pin connection status of the detection circuit is as follows: normally closed contacts 1-2 and 4-5 are closed, and LED indicator lights 1-2 and 4-5 are lit; normally open contacts 1-3 and 4-5 are open, and corresponding LED indicator lights 1-3 and 4-6 are off. When the aircraft operating system issues a command to supply pressure to the actuator retraction nozzle, the piston rod retracts. When the piston rod retracts to its full position, it triggers the lever to press the limit switch, forcing a change in the state of its internal contacts. Specifically, contacts 1-2 and 4-5 open, and the corresponding LED indicator lights 1-2 and 4-5 turn off; when contacts 1-3 and 4-5 close, the limit switch is activated. Figure 5 The corresponding LED indicator lights 1-3 and 4-6 on the circuit will light up.

[0119] In this embodiment, the LED connected to the retracted end of the actuator cylinder is a green LED.

[0120] The other parts of this embodiment are the same as any one of the embodiments 1-4 above, so they will not be described again.

[0121] Example 6:

[0122] This embodiment is based on any one of the embodiments 1-5 above, such as Figure 6 , Figure 7 As shown, the extended end limit switch detection module includes switch K3, switch K4, switch K5, a first electrical connector, and an extended end indicator unit;

[0123] The input terminal of the switch K3 is connected to the first voltage and current meter via the first electrical connector, and the output terminal of the switch K3 is connected to the input terminal of the protruding end indicator unit via the first electrical connector.

[0124] The input terminal of the switch K4 is connected to the first voltage and current meter via the first electrical connector, and the output terminal of the switch K4 is connected to the input terminal of the protruding end indicator unit via the first electrical connector.

[0125] The input terminal of switch K5 is connected to the first voltage and current meter via the first electrical connector, and the output terminal of switch K5 is connected to the input terminal of the protrusion end indicator unit via the first electrical connector.

[0126] The output terminal of the protruding end indicator unit is connected to the first voltage and current meter.

[0127] The protruding end indicator unit includes multiple resistors R3 connected in parallel and a red light-emitting diode D3;

[0128] The input terminals of multiple resistors R3 are connected to the output terminals of switches K3, K4, and K5 through the first electrical connector, and the output terminals of multiple resistors R3 are connected to the red light-emitting diode D3.

[0129] Multiple red LEDs D3 are connected to a first voltage and current meter.

[0130] Table 1. Pin Definitions for Limit Switches at the Retraction End of the Actuator Cylinder Piston Rod

[0131] pin number Function definition Remark 1 Working power supply 1+ Voltage +DC (28±0.2)V 2 Output signal 1 purple line 3 Output signal 1 4 Working power supply 2+ Voltage DC (28±0.2)V 5 Output signal 2 6 Output signal 2

[0132] Working Principle: This embodiment is a schematic diagram specifically applied to detect the limit switch signal at the extended end of the actuator piston rod. The electrical connector serves as the connection carrier for converting the aviation plug and socket. Wiring is performed according to pin definition table 3. In the free state of the limit switch at the extended end of the actuator piston rod, the internal pin connection status of the detection circuit is as follows: normally closed contacts 1-2, 4-5, and 9-8 are closed, and LED indicator lights 1-2, 4-5, and 9-8 are lit; normally open contacts 1-7, 4-6, and 9-3 are open, corresponding to the pins on the circuit. LED indicator lights 1-7, 4-6, and 9-3 are off. When the aircraft operating system issues a command to supply pressure to the actuator nozzle, the piston rod extends. When the piston rod extends to its end, it triggers the lever to press the limit switch, forcing the internal contact state to change. That is, contacts 1-2, 4-5, and 9-8 open, and the corresponding LED indicator lights 1-2, 4-5, and 9-8 turn off. Contacts 1-7, 4-6, and 9-3 close, and the corresponding LED indicator lights 1-7, 4-6, and 9-3 in the circuit light up.

[0133] Table 3. Pin Definitions for Limit Switches at the Extended End of the Actuator Cylinder Piston Rod

[0134] pin number Function definition Remark 1 Working power supply 1+ Voltage DC (15±0.2)V, current 100mA 2 Output signal 1 3 Output signal 1 4 Working power supply 2+ Voltage DC (15±0.2)V, current 100mA 5 Output signal 2 6 Output signal 2 9 Working power supply 3+ Voltage DC (15±0.2)V, current 100mA 8 Output signal 3 7 Output signal 3

[0135] The electrical connector provided in this embodiment is a small circular aviation electrical connector; the light-emitting diode connected to the extended end of the actuator cylinder in this embodiment is a red light-emitting diode.

[0136] The other parts of this embodiment are the same as any one of the above embodiments 1-5, so they will not be described again.

[0137] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications or equivalent changes made to the above embodiments based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A signal detection circuit for an actuator limit switch, characterized in that, It includes a power socket switch module, a first voltage conversion module, an extended end limit switch detection module, a second voltage conversion module, and a retracted end limit switch detection module; The power socket switch module receives AC mains power at its input terminal and its output terminal is connected to the input terminal of the extended end limit switch detection module via a first voltage conversion module and to the input terminal of the retracted end limit switch detection module via a second voltage conversion module. The output terminal of the extended end limit switch outputs an on / off signal for the extended end limit switch; The output terminal of the retractable end limit switch outputs a retractable end limit switch on / off signal; The power socket switch module is used to supply power after being connected to the power grid; The first voltage conversion module is used to convert AC power into a first voltage signal; The second voltage conversion module is used to convert AC mains power into a second voltage signal; The extension end limit switch detection module is used to generate an extension end limit switch on / off signal based on the first voltage signal, and to determine whether the landing gear is retracted / lowered based on the extension end limit switch on / off signal. The retractable end limit switch detection module is used to generate a retractable end limit switch on / off signal based on the second voltage signal, and to determine whether the landing gear is retracted / lowered based on the retractable end limit switch on / off signal.

2. The signal detection circuit for an actuator limit switch according to claim 1, characterized in that, The signal detection circuit of the actuator limit switch also includes a first voltage and current meter and a second voltage and current meter; The first voltage and current meter is positioned between the first voltage conversion module and the extended end limit switch detection module; The second voltage and current meter is positioned between the second voltage conversion module and the retractable end limit switch detection module; The first voltage and current meter is used to detect the contact quality of the extended end limit switch contacts based on the acquired first current and voltage change signal; The second voltage and current meter is used to detect the contact quality of the retractable limit switch contacts based on the acquired second current and voltage change signal.

3. The signal detection circuit for an actuator limit switch according to claim 1, characterized in that, The power switch socket module includes a socket J1, a resistor R0, and a light-emitting diode power indicator D1; One end of the resistor R0 is connected to the first output terminal of the socket J1, the first input terminal of the first voltage conversion module, and the first input terminal of the second voltage conversion module; the other end of the resistor R0 is connected to the input terminal of the LED power indicator D0. The output terminal of the LED power indicator D0 is connected to the second output terminal of the socket J1, the second input terminal of the first voltage conversion module, and the second input terminal of the second voltage conversion module. The socket J1 receives AC power at its input terminal and its third output terminal is connected to the third input terminal of the first voltage conversion module and the third input terminal of the second voltage conversion module.

4. The signal detection circuit for an actuator limit switch according to claim 1, characterized in that, The first voltage conversion module includes a first voltage conversion chip U1, a switch K1, a resistor R1, and a light-emitting diode D1; The input terminal of the first voltage conversion chip is connected to the output terminal of the power switch socket module, the first output terminal of the first voltage conversion chip is connected to switch K1, the second output terminal of the first voltage conversion chip is connected to the output terminal of light-emitting diode D1, and the third output terminal of the first voltage conversion chip is connected to ground. One end of the resistor R1 is connected to the input terminal of the switch K1 and the extended end limit switch detection module, and the other end is connected to the input terminal of the light-emitting diode D1. The output terminal of the light-emitting diode D1 is connected to the input terminal of the extended end limit switch detection module; The first voltage conversion chip is used to convert AC mains signal into 28V DC signal.

5. The signal detection circuit for an actuator limit switch according to claim 1, characterized in that, The second voltage conversion module includes a second voltage conversion chip U2, a switch K2, a resistor R2, and a light-emitting diode D2; The input terminal of the second voltage conversion chip is connected to the output terminal of the power switch socket module, the first output terminal of the second voltage conversion chip is connected to switch K2, the second output terminal of the second voltage conversion chip is connected to the output terminal of light-emitting diode D2, and the third output terminal of the second voltage conversion chip is connected to ground. One end of the resistor R2 is connected to the input terminal of the switch K2 and the retracted end limit switch detection module, and the other end is connected to the input terminal of the light-emitting diode D2. The output terminal of the light-emitting diode D2 is connected to the input terminal of the retraction end limit switch detection module; The second voltage conversion chip is used to convert AC mains signals into 15V DC signals.

6. The signal detection circuit for an actuator limit switch according to claim 2, characterized in that, The extended end limit switch detection module includes switch K3, switch K4, switch K5, a first electrical connector, and an extended end indicator unit; the input terminal of switch K3 is connected to a first voltmeter and ammeter through the first electrical connector, and the output terminal of switch K3 is connected to the input terminal of the extended end indicator unit through the first electrical connector. The input terminal of the switch K4 is connected to the first voltage and current meter via the first electrical connector, and the output terminal of the switch K4 is connected to the input terminal of the protruding end indicator unit via the first electrical connector. The input terminal of switch K5 is connected to the first voltage and current meter via the first electrical connector, and the output terminal of switch K5 is connected to the input terminal of the protrusion end indicator unit via the first electrical connector. The output terminal of the protruding end indicator unit is connected to the first voltage and current meter.

7. The signal detection circuit for an actuator limit switch according to claim 6, characterized in that, The protruding end indicator unit includes multiple resistors R3 connected in parallel and a red light-emitting diode D3; The input terminals of multiple resistors R3 are connected to the output terminals of switches K3, K4, and K5 through the first electrical connector, and the output terminals of multiple resistors R3 are connected to the red light-emitting diode D3. Multiple red LEDs D3 are connected to a first voltage and current meter.

8. The signal detection circuit for an actuator limit switch according to claim 2, characterized in that, The retraction end limit switch detection module includes switch K6, switch K7, second electrical connector, and retraction end indicator unit; The input terminal of switch K6 is connected to the second voltage and current meter via the second electrical connector, and the output terminal of switch K6 is connected to the input terminal of the retraction end indicator unit via the second electrical connector. The input terminal of switch K7 is connected to the second voltage and current meter via the second electrical connector, and the output terminal of switch K7 is connected to the input terminal of the retraction end indicator unit via the second electrical connector. The output terminal of the retractable end indicator unit is connected to the second voltage and current meter.

9. The signal detection circuit for an actuator limit switch according to claim 8, characterized in that, The retraction end indicator unit includes multiple resistors R4 connected in parallel and a green light-emitting diode D4; The input terminals of multiple resistors R4 are connected to the output terminals of switches K6 and K7 via a second electrical connector, and the output terminals of multiple resistors R4 are connected to a green light-emitting diode D4. Multiple green light-emitting diodes D4 are connected to a second voltage and current meter.

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