Electric seat electronic controller for aircraft cockpit and control implementation method of electric seat electronic controller

Abstract

The invention discloses an aircraft electric seat electronic controller and a control logic implementation method thereof. The electronic controller is composed of a seat control box, a seat operation panel, a USB charging module, a limit switch assembly and three direct current motors with Hall sensors. The seat control box internally comprises a 28V filtering circuit, an anti-reverse connection and anti-surge protection circuit, a double-path 5V isolation power supply, an optical coupler isolation logic control circuit and a motor driving circuit; the operation panel is integrated with seven film keys and a one-key reset function; the limit switch assembly provides six posture limit positions and a grounding protection signal. According to the control logic, key detection, mistaken touch prevention, limit hardware interlocking and one-key time sequence resetting are achieved through a pure hardware logic gate, and the requirements for DO-160G electromagnetic compatibility and aviation high reliability can be met without a DSP or a software program. Through the scheme of'full hardware logic + Hall closed loop ', the program design error risk is remarkably reduced, the after-sales troubleshooting cost is reduced, and the method can be quickly transplanted to various 28V airborne electric seat platforms.

Description

Technical Field

[0001] This invention relates to the field of aircraft seat control technology, and in particular to an electronic controller for an electric seat in an aircraft cockpit and its control implementation method. Background Technology

[0002] Currently, China mainly relies on imports for aircraft electric seat controllers. Domestic solutions mostly adopt DSP or microcontroller architectures, requiring manual writing, debugging, and verification of a large amount of software code, which presents the following problems:

[0003] 1. Program design errors and complex version management lead to occasional functional abnormalities;

[0004] 2. The control chip must meet aerospace-grade screening requirements, resulting in a long procurement cycle and high cost;

[0005] 3. Limit position protection relies on software judgment, which has a long response time and poses a risk of motor stalling and burnout;

[0006] 4. On-site upgrades or troubleshooting require specialized tooling and software environment, resulting in high maintenance costs.

[0007] Therefore, there is an urgent need for an electric seat controller that can achieve highly reliable control and protection without software and with only hardware. Summary of the Invention

[0008] The purpose of this invention is to provide an electronic controller for an electric seat in an aircraft cockpit and a method for controlling it, thereby solving the aforementioned problems in the prior art.

[0009] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0010] An electronic controller for an aircraft electric seat includes:

[0011] Seat control box, the seat control box has:

[0012] The filter circuit is used to filter the 28V DC input on the machine.

[0013] The reverse connection and surge protection circuit is electrically connected to the filter circuit and automatically disconnects the output when the positive and negative terminals of 28V DC are reversed.

[0014] The first power module is used to convert 28V DC to 5V DC to power the control circuit.

[0015] The second power module is used to convert 28V DC to a second 5V DC to power the seat control panel, indicator lights and isolation circuit.

[0016] The seat control panel, installed on the seat armrest, has seven buttons: backrest forward, backrest backward, leg rest up, leg rest down, leg rest forward, leg rest backward, and one-button reset. The seat control panel is electrically connected to the second power module and control circuit.

[0017] The limit switch assembly includes six attitude limit switches and one ground contact protection limit switch. The limit switch assembly is electrically connected to the control circuit.

[0018] The drive motor assembly includes three DC motors with Hall sensors, which are used to drive the seat back back forward and backward, the leg support forward and backward, and the leg support extension and retraction, respectively. The drive motor assembly is electrically connected to the control circuit.

[0019] A USB charging module is used to convert 28V DC to USB-A5V output and is installed on the seat armrest;

[0020] The control circuit includes:

[0021] Input / output optocoupler isolation circuit;

[0022] The logic signal driving circuit, composed of AND gate chips, NOT gate chips and MOS circuits, is used to realize key signal detection and motor drive control to prevent accidental touch.

[0023] Limit signal recognition circuit, used to immediately cut off the motor power supply when any limit switch is triggered;

[0024] The D latch and delay circuit are used to synchronously reset all motors to their initial position when a one-key reset signal is received.

[0025] Furthermore, the logic signal driving circuit is configured as follows:

[0026] When any button is pressed, a forward or reverse signal for the motor corresponding to that button is output.

[0027] When the button is released, the motor drive signal is immediately canceled, causing the motor to stop and maintain its current position;

[0028] When two or more buttons are pressed simultaneously, all input signals are cut off within 10ms through a combination of AND gate chip and MOS circuit to prevent accidental touch.

[0029] Furthermore, the limit signal recognition circuit includes:

[0030] The hardware interlock circuit has a response time of ≤1ms and is used to directly shut down the MOSFET drive stage when any limit switch is triggered.

[0031] The software redundancy judgment loop is used to make a secondary judgment based on the position signal of the Hall sensor and cut off the motor power supply within 5ms when the hardware interlock loop fails.

[0032] Furthermore, the D latch and delay circuit are configured as follows:

[0033] A reset command is triggered after the one-key reset button is continuously pressed for more than 500ms.

[0034] During the reset process, the backrest motor, the front and rear leg support motors, and the extension leg support motor are controlled sequentially according to the preset timing to return to the mechanical origin, and the power is automatically cut off and locked after all motors reach the origin position.

[0035] Furthermore, the USB charging module includes:

[0036] Synchronous step-down DC-DC converter with an efficiency ≥92%;

[0037] Output overcurrent, overvoltage and short circuit protection circuit, with overcurrent protection point of 1.5A±10% and overvoltage protection point of 5.6V±2%;

[0038] The output TVS diode is used to meet the DO-160G aviation electromagnetic compatibility requirements.

[0039] Furthermore, a detachable shielded cable is used to connect the control circuit and the drive motor assembly. The shielding layer of the shielded cable is grounded at a single point to the metal shell of the seat control box through a 360° metal pressure ring to reduce electromagnetic interference.

[0040] Furthermore, the control circuit also includes:

[0041] Motor current sampling circuit, used to detect motor bus current in real time;

[0042] The stall detection circuit is used to immediately cut off the motor power supply and report a fault signal when the current continuously exceeds the threshold within 50ms after the motor starts and the Hall sensor feedback speed is zero.

[0043] Furthermore, the metal casing of the seat control box is integrally milled from aluminum alloy, and conductive rubber sealing strips are provided at the joints of the casing to achieve an IP54 protection rating and electromagnetic shielding effectiveness of ≥60dB@1GHz.

[0044] A method for implementing control logic for an aircraft electric seat, comprising the following steps using the aforementioned aircraft electric seat electronic controller:

[0045] a) After the system is powered on, it performs a self-test. If any limit switch malfunctions or Hall sensor signal is detected as missing, the motor will be prohibited from starting and a fault indication will be output.

[0046] b) In normal working mode, the key signals are collected in real time. When a single key press is detected, the corresponding motor drive is executed; when multiple keys are pressed at the same time, the anti-mistouch logic is executed.

[0047] c) During motor operation, the position signal of the Hall sensor and the status of the limit switch are collected in real time. When any limit switch is triggered, the hardware interlock power is immediately executed.

[0048] d) When the one-key reset button is continuously pressed for more than 500ms, the system enters the reset mode and controls each motor to return to the mechanical origin according to the preset timing sequence.

[0049] e) After the reset is complete, power off and lock all motors, and turn off the fault indicator lights.

[0050] Furthermore, the reset timing in step d) includes:

[0051] First, control the backrest motor to return to the origin at the first speed;

[0052] Then control the front and rear motors of the leg support to return to the origin at the second speed;

[0053] Finally, control the leg support telescopic motor to return to the origin at the third speed;

[0054] The first, second, and third speeds decrease sequentially to avoid mechanical impact and reduce the total reset time.

[0055] The beneficial effects of this invention are as follows: This invention discloses a control logic implementation method for an aircraft electric seat, which has the following beneficial effects:

[0056] High reliability: All control functions are implemented using pure hardware logic gate circuits, completely eliminating the risk of software bugs; the hardware interlock circuit cuts off the motor power supply in less than 1ms to avoid stalling.

[0057] Low maintenance costs: No software burning, debugging and version management are required, and modules can be directly interchanged, reducing the cost of aircraft parts turnover and manual maintenance.

[0058] High compatibility: 28V aviation DC input, built-in reverse connection protection, surge protection, EMI filtering, meets DO-160G requirements, and can directly replace existing imported controllers.

[0059] Excellent user experience: The one-button reset function can complete the return of the entire attitude to zero within 3 seconds; the USB-A5V / 1.5A charging port meets the charging needs of pilots' electronic devices.

[0060] Compact structure: integrated aluminum alloy shell, IP54 protection, single-sided cable exit, weight <450g, easy to install on the side armrest of the seat. Attached Figure Description

[0061] Figure 1 This is a schematic diagram of the electric seat control system of the present invention;

[0062] Figure 2 This is a diagram of the internal circuit structure of the seat control box;

[0063] Figure 3 This is a schematic diagram of the layout of the seat control panel;

[0064] Figure 4 This is a flowchart illustrating the control logic implementation method for an aircraft electric seat according to the present invention. Detailed Implementation

[0065] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0066] Reference Figure 1 , Figure 2 and Figure 3 An electronic controller for an aircraft electric seat, as shown, includes:

[0067] Seat control box, the seat control box has:

[0068] The filter circuit is used to filter the 28V DC input on the machine.

[0069] The reverse connection and surge protection circuit is electrically connected to the filter circuit and automatically disconnects the output when the positive and negative terminals of 28V DC are reversed.

[0070] The first power module is used to convert 28V DC to 5V DC to power the control circuit.

[0071] The second power module is used to convert 28V DC to a second 5V DC to power the seat control panel, indicator lights and isolation circuit.

[0072] The seat control panel, installed on the seat armrest, has seven buttons: backrest forward, backrest backward, leg rest up, leg rest down, leg rest forward, leg rest backward, and one-button reset. The seat control panel is electrically connected to the second power module and control circuit.

[0073] The limit switch assembly includes six attitude limit switches and one ground contact protection limit switch. The limit switch assembly is electrically connected to the control circuit.

[0074] The drive motor assembly includes three DC motors with Hall sensors, which are used to drive the seat back back forward and backward, the leg support forward and backward, and the leg support extension and retraction, respectively. The drive motor assembly is electrically connected to the control circuit.

[0075] A USB charging module is used to convert 28V DC to USB-A5V output and is installed on the seat armrest;

[0076] The control circuit includes:

[0077] Input / output optocoupler isolation circuit;

[0078] The logic signal driving circuit, composed of AND gate chips, NOT gate chips and MOS circuits, is used to realize key signal detection and motor drive control to prevent accidental touch.

[0079] Limit signal recognition circuit, used to immediately cut off the motor power supply when any limit switch is triggered;

[0080] The D latch and delay circuit are used to synchronously reset all motors to their initial position when a one-key reset signal is received.

[0081] In some embodiments, the above structure is described as follows:

[0082] I. 28V Input and Power Supply Link

[0083] Filtering circuit

[0084] The π-type CLC topology is adopted: C1 = C3 = 100μF / 50V tantalum capacitors, L1 = 4.7μH shielded power inductor, cutoff frequency ≈150kHz, and conducted interference attenuation ≥40dB for DO-160G specified 150kHz~30MHz.

[0085] A TVS diode SMBJ33CA connected in parallel at the input can absorb a surge of ±600W / 10 / 1000μs.

[0086] Reverse connection protection and surge protection circuit

[0087] After filtering, a P-channel MOSFET IRF4905 is connected in series as an ideal diode, with its source connected to the positive input and its drain connected to the subsequent stage; the gate is regulated to ground at 18V via a Zener diode. When the input polarity is reversed, the body diode is reverse-biased and the MOSFET cannot conduct, achieving zero-loss reverse isolation.

[0088] A 20D471K varistor is connected in parallel at the same location to handle ±2kV line-to-line surges.

[0089] First power supply module (power supply for control logic)

[0090] The LM2675-5.0 switching regulator is used, with an input range of 8-40V, an output of 5V / 1A, and an efficiency of >90%. The output terminal has an LCπ-type secondary filter, 100μF / 10V+4.7μH+100μF, to ensure that the 5V ripple is <30mVpp.

[0091] Second power supply module (panel / isolated power supply)

[0092] The B0505S-1W isolated DC-DC converter is used, rated at 5V→5V / 200mA, with an isolation withstand voltage of 1kVDC and a common-mode transient immunity of >25kV / μs, ensuring complete isolation between the Hall sensor, LED, optocoupler and main power ground.

[0093] II. Seat Control Panel

[0094] The panel measures 60mm x 45mm and features seven 0.3mm travel stainless steel membrane buttons (travel life ≥ 1,000,000 times). The button matrix is ​​connected to the control box via a 0.1" pitch FPC flexible cable. The cable is twisted in pairs and shielded with a braided mesh throughout, and terminated with a 360° crimped metal ring.

[0095] The seven light guide pillars are made of transparent PC material, and the bottom-mounted white LEDs are driven by a 2N3904 transistor with a constant current of 5mA from the second 5V, with a brightness of >300mcd, which meets the requirements for readability in the cockpit under sunlight.

[0096] III. Limit Switch Assembly

[0097] Six posture limit switches: Honeywell SS41F single-pole Hall switches with normally closed output (0V effective), installed at the mechanical limits of the backrest front and back, leg support up and down, and leg support front and back; the ground contact protection switch is a roller lever type micro switch installed at the bottom of the seat.

[0098] All switching signals are pulled up to the second 5V via a 10kΩ resistor, and then sent to the logic gate array after being isolated by an HCPL-063L high-speed optocoupler to ensure >1kV common-mode immunity.

[0099] IV. Drive Motor Assembly

[0100] Three Mabuchi RS-555PH-3255 DC motors, rated at 24V, with a no-load speed of 6000rpm, have a built-in bipolar latched Hall effect sensor (A3144) and output 6 pulses per revolution, which are then shaped by a 74HC14 Schmitt trigger and fed into an AND gate array.

[0101] The motor drive stage is a three-phase full-bridge, using IRF3205×6, with the upper tube driven by IR2184 bootstrap, PWM frequency of 25kHz, and hardware current limit of 0.7V / Rsense≈3A.

[0102] V. USB charging module

[0103] The MP2359 synchronous buck converter chip has an input of 4.75-28V, an output of 5V / 1.5A, and an efficiency of 92% (12V input).

[0104] Output stage: 1.5APPTC resettable fuse + 5.6VTVS SMBJ5.0CA; short-circuit current limiting foldback to 0.3A, temperature rise <15K.

[0105] VI. Core of the Control Circuit

[0106] Input / output optocoupler isolation circuit

[0107] Signal flow: Key matrix → HCPL-063L → SN74HC08 → IR2184; Limit switch → HCPL-063L → SN74HC08 gate; Achieves >2.5kV withstand voltage and >20kV / μs common mode rejection.

[0108] Logic signal driving circuit

[0109] AND gate chip SN74HC08: Implements "single-key active, multi-key shielded" - any key is sent to a 4-input AND gate after being optocoupled, and the other inputs are inverted by NOT gate 74HC04, ensuring that the output is high only if and only if a single key is active.

[0110] MOS circuit: The IRFZ44N is used as a high-side switch. The gate is driven by a 100Ω resistor. When turned off, the gate is pulled down by a 10kΩ resistor to ensure a turn-off time of <100ns.

[0111] Limit signal recognition circuit

[0112] Hardware interlock: Six normally closed attitude Hall effect contacts are connected in series to directly drive the IR2184 SD pin. Open circuit means shutdown, response time <1ms.

[0113] Redundancy determination: If the Hall speed is <10Hz and the current is >th threshold (0.7V) for 50ms, the 74HC123 monostable is triggered, and the SD is pulled low within 5ms.

[0114] D latch and delay circuit

[0115] CD4043 Quad D Latch: The one-key reset button triggers latching after a 500ms delay via RC integration (R=100kΩ, C=4.7μF); Q0-Q2 sequentially output 2s / 1.5s / 1s pulses to control the corresponding motors.

[0116] Pulse end detection: Using 74HC123 monostable + optocoupler feedback, after confirming that the Hall pulses of the three motors have returned to zero, the power supply to the motors is cut off through the high-side switch of the MOSFET to complete zero power consumption lockout.

[0117] VII. Cables and Shielding

[0118] Drive cable: 3×20AWG+6×24AWG shielded multi-core wire, shielding coverage >85%, terminated with AMP CPC37-pin quick-locking connector, 360° pressure ring and single-point grounding of aluminum shell, shielding effectiveness >40dB@100MHz.

[0119] VIII. Machinery and Protection

[0120] The control box housing is a 6061-T6 CNC machined whole, with conductive oxidation and painting on the outer surface. The cover and housing are filled with conductive fluororubber strips with a compression of 25%, achieving IP54 and 60dB@1GHz shielding.

[0121] The PCB is a 4-layer FR-4TG170 with a complete ground plane on the inner layer. Key signal lines are routed on the inner layer with accompanying ground vias to meet the DO-160G radiated emission Class H requirements.

[0122] Through the detailed construction described above, this electronic controller, without using any microcontroller or DSP, completes the three-degree-of-freedom electric adjustment of the seat, hardware anti-accidental touch, extreme hardware interlock, one-key reset sequence control, USB 5V / 1.5A charging, and DO-160G aerospace-grade EMC / reliability requirements, achieving the overall goal of "zero software, high reliability, fast interchangeability, and low maintenance".

[0123] Furthermore, the logic signal driving circuit is configured as follows:

[0124] When any button is pressed, a forward or reverse signal for the motor corresponding to that button is output.

[0125] When the button is released, the motor drive signal is immediately canceled, causing the motor to stop and maintain its current position;

[0126] When two or more buttons are pressed simultaneously, all input signals are cut off within 10ms through a combination of AND gate chip and MOS circuit to prevent accidental touch.

[0127] I. Circuit Topology Overview

[0128] The logic signal driving circuit consists of four cascaded stages: "key encoding network → anti-accidental touch AND gate matrix → MOS driver stage → motor bridge arm". All of them use industrial-grade CMOS devices (74HC series) and low Rds(on) MOSFETs to ensure that the entire process of "key recognition → drive cancellation" is completed within 10ms.

[0129] II. Keypad Encoding Network

[0130] The panel has 7 buttons (S1 to S7) that use independent single-pole normally open membrane switches. One end is connected to GND, and the other end is connected to +5V through a 10kΩ pull-up resistor and connected in series with a 100nF ceramic capacitor for hardware debouncing.

[0131] Each key signal is isolated by an HCPL-063L high-speed optocoupler and then sent to the input of a SN74HC08 quad AND gate.

[0132] Positive signal: Key pressed → optocoupler turns on → AND gate input pulls low → inverted by a single NOT gate SN74HC04 to "active high".

[0133] Inverted signal: After being inverted again by 74HC04, it becomes "active low" and is used for interlocking logic.

[0134] III. Preventing Accidental Touches and Gate Matrix

[0135] "Single-key valid" logic

[0136] Seven positive signals are simultaneously fed into an eight-input AND gate (cascaded CD4082) to achieve "output high only when one and only one input is high".

[0137] The AND gate output is then shaped by two stages of NOT gates to form a "single-key confirmation" signal.

[0138] "Multi-key blocking" logic

[0139] All 7 positive signals are passed through a 7-input OR gate (CD4078) to obtain the "multi-key flag"; when ≥2 keys are active at the same time, the OR gate outputs high.

[0140] The "multi-key flag" directly drives the N-channel MOSFET Q1 (IRLZ44N). The gate RC filter (R=1kΩ, C=100nF) ensures that it turns on after a 10ms delay, pulls down the gate bus of the subsequent MOS driver stage, and immediately shuts down all motors.

[0141] The 10ms delay is determined by the RC constant τ = 100μs, but the threshold of the subsequent Schmitt trigger (74HC14) is 2.1V, ensuring reliable switching within 10ms.

[0142] IV. MOS Driver Stage

[0143] Motor direction control

[0144] Each motor H-bridge consists of 4 IRF3205 chips.

[0145] The direction signal "DIR" comes from the single-key confirmation logic: high → forward, low → reverse; it is also connected to the interlock bus.

[0146] When "Single Key Confirmation" is high, DIR drives the corresponding bridge arm via IR2184 bootstrap; when the key is released or accidentally triggered, DIR is immediately pulled low, and the IR2184SD pin is simultaneously pulled low (<100ns), turning off all the upper and lower transistors of the bridge arm.

[0147] Enable control

[0148] The enable EN signal is generated by passing the "single-key confirmation" and "multi-key flag" signals through two NOR gates (CD4001):

[0149] No key pressed → EN = 0;

[0150] Press a single key → EN = 1;

[0151] Press ≥2 key → EN = 0 (cancel immediately).

[0152] The EN pin directly drives the IN pin of the IR2184, achieving a zero-delay response of "button pressed → bridge arm turned on, button released / accidentally pressed → bridge arm turned off".

[0153] V. Timing and Waveform Verification

[0154] Press one key:

[0155] t0: Button closed → Optocoupler delay 3μs → AND gate output high 1.2μs → IR2184 IN=1 → Bridge arm turned on.

[0156] t1: Button release → AND gate output low for 1.2μs → IR2184 IN=0 → Bridge arm off; motor stops coasting due to inertia.

[0157] Accidental double button press:

[0158] t0: The second button is closed → the OR gate outputs high for 1μs → Q1 gate starts charging → Q1 turns on after 10ms → the gate bus is pulled low → IR2184 is turned off.

[0159] Within 10ms, the peak current of the motor has not exceeded the safety threshold, effectively preventing mechanical shock.

[0160] VI. Selection and Parameters of Key Components

[0161]

[0162] VII. Key Points of PCB Layout

[0163] The logic area and power area are separated into two cavities: the optocoupler and 74HC device are located in the "digital ground" area, and the MOSFET and high-current traces are located in the "power ground" area, with a single-point star connection between the two grounds.

[0164] Parallel ground lines are laid alongside each button trace to form a microstrip line, reducing common-mode coupling above 10MHz.

[0165] The MOS gate trace is 0.5mm wide and <15mm long, and a 10kΩ pull-down resistor and a 15V TVS are added between the gate and source to prevent electrostatic discharge.

[0166] Through the above hardware cascade design, this logic signal driving circuit can output a direction signal instantly when a single key is pressed, and can cancel the drive instantly when the key is released. At the same time, in the case of accidental touch or multiple keys, it can reliably cut off all power paths within 10ms, which fully meets the aviation-grade requirements for fast control without the risk of software failure.

[0167] Furthermore, the limit signal recognition circuit includes:

[0168] The hardware interlock circuit has a response time of ≤1ms and is used to directly shut down the MOSFET drive stage when any limit switch is triggered.

[0169] The software redundancy judgment loop is used to make a secondary judgment based on the position signal of the Hall sensor and cut off the motor power supply within 5ms when the hardware interlock loop fails.

[0170] Furthermore, the D latch and delay circuit are configured as follows:

[0171] A reset command is triggered after the one-key reset button is continuously pressed for more than 500ms.

[0172] During the reset process, the backrest motor, the front and rear leg support motors, and the extension leg support motor are controlled sequentially according to the preset timing to return to the mechanical origin, and the power is automatically cut off and locked after all motors reach the origin position.

[0173] Furthermore, the USB charging module includes:

[0174] Synchronous step-down DC-DC converter with an efficiency ≥92%;

[0175] Output overcurrent, overvoltage and short circuit protection circuit, with overcurrent protection point of 1.5A±10% and overvoltage protection point of 5.6V±2%;

[0176] The output TVS diode is used to meet the DO-160G aviation electromagnetic compatibility requirements.

[0177] Furthermore, a detachable shielded cable is used to connect the control circuit and the drive motor assembly. The shielding layer of the shielded cable is grounded at a single point to the metal shell of the seat control box through a 360° metal pressure ring to reduce electromagnetic interference.

[0178] Furthermore, the control circuit also includes:

[0179] Motor current sampling circuit, used to detect motor bus current in real time;

[0180] The stall detection circuit is used to immediately cut off the motor power supply and report a fault signal when the current continuously exceeds the threshold within 50ms after the motor starts and the Hall sensor feedback speed is zero.

[0181] Furthermore, the metal casing of the seat control box is integrally milled from aluminum alloy, and conductive rubber sealing strips are provided at the joints of the casing to achieve an IP54 protection rating and electromagnetic shielding effectiveness of ≥60dB@1GHz.

[0182] Reference Figure 4 The control logic implementation method for an aircraft electric seat shown herein uses the aforementioned aircraft electric seat electronic controller to perform the following steps:

[0183] S100 After the system is powered on, it performs a self-test. If any limit switch is found to be abnormal or the Hall sensor signal is missing, the motor is prohibited from starting and a fault indication is output.

[0184] Once the system is powered on with 28V onboard DC, the power chip first establishes a stable 5V for itself and the logic section.

[0185] Once the 5V is established, a hardware self-test process is immediately initiated, which is completed entirely by pure circuits without running any code.

[0186] Limit Link Check

[0187] The six attitude limit Hall switches and one grounding microswitch are all connected in series in a "normally closed" manner to form a circuit.

[0188] At the instant of power-on, the comparator immediately measures the voltage of this circuit to ground:

[0189] If the circuit is closed, the voltage is approximately 0V, which is considered normal.

[0190] If any circuit is open, the voltage is pulled up to 5V, and the comparator immediately flips, latching a "limit exception" signal.

[0191] Hall sensor inspection

[0192] Sending a weak pulse with a 10% duty cycle to the three motor drive axles simultaneously results in a current of only 0.5A, which is insufficient to make the seat move.

[0193] Within 20ms, the counter counts each Hall pulse:

[0194] Pulse present → Normal;

[0195] No pulse → latches the "Hall Missing" signal.

[0196] Fault Summary and Startup Inhibition

[0197] If either "extreme anomaly" or "Hall absence" is detected, "system fault" latch is triggered.

[0198] Latch immediately:

[0199] Pulling down the shutdown pin of the motor driver chip forces all bridge arms to shut down;

[0200] The red fault light illuminates and flashes rapidly at 2Hz.

[0201] Pull the open-circuit fault line low to allow external LRU detection.

[0202] User Prompt

[0203] The fault light flashes five times and then switches to a 1Hz heartbeat until the power is cut off and then restored.

[0204] In this state, all buttons are disabled by hardware, and the motor cannot start, ensuring absolute safety.

[0205] The entire self-test, from power-on to completion, takes no more than 100ms and is entirely completed by hardware logic with zero software involvement.

[0206] S200: In normal working mode, it collects key signals in real time. When a single key is pressed, it executes the corresponding motor drive; when multiple keys are pressed simultaneously, it executes the anti-mistouch logic.

[0207] The S200's "real-time button-driver" process is entirely completed by hardware logic gates, without a microcontroller or software.

[0208] Real-time data collection

[0209] One end of each of the seven membrane buttons is grounded, and the other end is pulled up to 5V via a 10kΩ resistor, with a 100nF capacitor connected in parallel for debouncing.

[0210] The key signal is first isolated by a high-speed optocoupler, and then sent to the "single key identification matrix" composed of a 74HC08 AND gate and a 74HC04 NOT gate.

[0211] The matrix output has only one line:

[0212] The AND gate outputs high if and only if one button line is pulled low, indicating "single button active";

[0213] If two or more button lines are pulled low at the same time, the OR gate will immediately output high, indicating "multiple button mis-touch".

[0214] Single-key driver

[0215] The "single key valid" signal directly activates the drive channel in the corresponding direction:

[0216] When a high level is sent to the input pin of the IR2184, the bridge arm is turned on, and the motor starts to rotate forward or in reverse.

[0217] As soon as the button is released, the pull-up resistor immediately pulls the signal back to a high level, the I R2184 input goes low, the bridge arm turns off, the motor stops and remains in its current position by relying on the self-locking worm gear.

[0218] Multi-key anti-accidental touch

[0219] The "multi-key accidental touch" signal does two things simultaneously:

[0220] A 1kΩ / 100nF RC network (time constant 100μs) drives an N-channel MOSFET.

[0221] After the MOSFET is turned on, it forcibly pulls the turn-off pin of the IR2184 low, cutting off all bridge arms within 100ns.

[0222] The entire process, starting from the closing of the second button, takes no more than 10ms to ensure that the motor will not move erratically or stall due to simultaneous commands.

[0223] Thus, the system can "start with one key, stop when the key is released, and lock with multiple keys" at any time.

[0224] S300: During motor operation, the position signal of the Hall sensor and the status of the limit switch are collected in real time. When any limit switch is triggered, the hardware interlock power is immediately executed.

[0225] The S300's "real-time monitoring - hardware interlock power-off" is entirely implemented using analog-digital hybrid hardware circuitry, as described below:

[0226] Dual-channel signal real-time acquisition

[0227] Hall effect sensor: Each motor is equipped with a bipolar Hall effect sensor. The pulse is shaped by a Schmitt trigger and then directly enters the counting / frequency discrimination network.

[0228] Limit switches: Six attitude limits plus one ground contact, all normally closed Hall / micro switches, connected in series to form a "limit chain". One end of the chain is grounded, and the other end is pulled up to 5V via a 10kΩ resistor and directly fed to the comparator input.

[0229] Limit trigger instantaneous action

[0230] When the motor is running, if any limit switch is activated, the limit chain will be broken, and the comparator input will be pulled up to 5V.

[0231] The comparator has a toggle threshold of 2.1V and a hysteresis of 0.3V to ensure anti-jitter performance.

[0232] After the flip, the high-level output immediately drives the N-channel MOSFET, pulling the SD (off) pin of the IR2184 low.

[0233] From chain disconnection to bridge arm shutdown, the entire process takes less than 1ms. The motor bus current decays to zero within 1ms, preventing any mechanical impact.

[0234] Hall redundancy monitoring (a second safeguard in case of limit switch failure)

[0235] The counting / discriminating network checks the Hall pulse count every 2ms: if the pulse increment is less than 2 within 2ms, it is judged as "zero speed".

[0236] Meanwhile, the current sampling amplifier monitors the bus current in real time: if the current continues to exceed 2A and the zero speed flag is set, the monostable multivibrator 74HC123 starts a 5ms pulse, which also pulls the SD low.

[0237] Therefore, even if the limit switch sticks or breaks, the system can still cut off power again within 5ms, ensuring absolute safety.

[0238] Through hard-wired interlocking of limit chains and Hall / current redundancy, the two channels are independent of each other. If one channel fails, the other channel can still be quickly powered off, achieving full-process limit protection without software or blind spots.

[0239] S400: When the one-key reset button is continuously pressed for more than 500ms, it enters the reset mode and controls each motor to return to the mechanical origin according to the preset timing sequence.

[0240] Button recognition

[0241] The one-key reset button is integrated using an RC circuit consisting of a 100kΩ resistor and a 4.7μF capacitor. The integrated voltage reaches 3.3V only when the button is held down for ≥500ms, triggering the CD4043D latch to set and generating the "reset start" signal. Short presses or bounces will not exceed the 3.3V threshold, preventing false triggering.

[0242] Reset Startup

[0243] After the latch is set, the following hard logic action is executed immediately:

[0244] First, send a "reset enable" high level signal, and simultaneously disable all normal arrow key inputs;

[0245] The 74HC4060 oscillator divider is activated to generate three sets of non-overlapping timing pulses, which correspond to the three motors of the backrest, the front and rear of the leg support, and the extension of the leg support, respectively.

[0246] Timing arrangement (implemented by cascading three D flip-flops)

[0247] ① Backrest motor: Powered immediately, it returns to zero first at 80% of the rated PWM;

[0248] ② Leg support front and rear motors: After the backrest is in position (Hall pulse disappears + limit chain closes), start after a 100ms delay and return to zero with 60% PWM;

[0249] ③ Leg support telescopic motor: After the first two stages are all in position, there is a 100ms delay before starting, and it returns to zero with 40% PWM.

[0250] Decreasing speed avoids mechanical impact and shortens the total reset time (approximately 3 seconds).

[0251] Origin determination

[0252] Hardware monitoring during the zero-return process of each motor stage:

[0253] The Hall pulse remained unchanged for 20ms.

[0254] The limit chain closes again;

[0255] If both conditions are met, it is judged as "in place", the corresponding trigger is cleared, and the power supply to the motor arm is cut off.

[0256] Reset complete

[0257] Once all three motors are in position, the final reset signal resets the master reset latch, returning the entire unit to "standby" mode. The red reset indicator light goes out, and the standard directional keys become active again. The entire process requires no software intervention and is precisely controlled by logic gates, counters, and RC delays.

[0258] S500: After the reset is complete, all motors will be powered off and locked, and the fault indicator lights will be turned off.

[0259] Origin confirmation

[0260] When the third motor (leg extension) returns to the mechanical origin, its "position" signal immediately triggers a 74HC123 monostable circuit, generating a 50ms positive pulse, named the "reset completion pulse".

[0261] Full bridge power failure

[0262] The rising edge of the "reset completion pulse" simultaneously pulls the SD pin of the IR2184 low, turning off all the upper and lower transistors of the H-bridge of the three motors, and the bus current drops to 0 within 1ms.

[0263] The same pulse is inverted by a NOT gate and drives a high-side P-channel MOSFET to cut off the positive power supply of all motors, ensuring zero-power lockout.

[0264] Mechanical holding

[0265] After the motor is powered off, the various mechanisms of the seat rely on the worm gear self-locking to maintain their original position and will not be displaced due to gravity or vibration.

[0266] The malfunction indicator light is off.

[0267] The falling edge of the "reset completion pulse" triggers the 74HC74 clear pin, resetting the fault latch → the red LED on the panel immediately turns off.

[0268] If there are no other malfunctions, the system enters a completely silent standby state, waiting for the next key press.

[0269] Furthermore, the reset timing in step S400 includes:

[0270] First, control the backrest motor to return to the origin at the first speed;

[0271] Then control the front and rear motors of the leg support to return to the origin at the second speed;

[0272] Finally, control the leg support telescopic motor to return to the origin at the third speed;

[0273] The first, second, and third speeds decrease sequentially to avoid mechanical impact and reduce the total reset time.

[0274] Speed ​​Classification

[0275] Three RC oscillators are used to generate three PWM signals of different frequencies, which serve as the "first, second, and third" speed references:

[0276] First speed: duty cycle 80%, corresponding to RC time constant R1C1 = 1ms (≈25kHz).

[0277] Second speed: duty cycle 60%, corresponding to RC time constant R2C2=1.5ms (≈17kHz).

[0278] Third speed: duty cycle 40%, corresponding to RC time constant R3C3=2ms (≈12kHz).

[0279] Sequential triggering

[0280] After the one-key reset is confirmed, the D latch first outputs a high level, turning on the "first speed" oscillator and energizing only the backrest motor.

[0281] The backrest is in position signal (Hall pulse disappears and limit chain closes) is delayed by 100ms by a 74HC123 monostable multivibrator before triggering the second latch, which shuts down the first speed and turns on the "second speed" oscillator, so that only the front and rear motors of the leg support are powered.

[0282] After the leg support reaches its forward and backward positions, a 100ms delay is also set to trigger the third latch, which disables the second speed and enables the "third speed" oscillator, driving the leg support extension motor back to zero.

[0283] Origin detection

[0284] When each stage motor returns to its origin, the hardware simultaneously monitors for "Hall zero pulse + limit chain closure". Once these conditions are met, the completion flag for that stage is immediately latched, and the power supply to that motor is automatically cut off.

[0285] Termination condition

[0286] After the third-level completion flag is set, the global reset completion pulse is generated, all PWM sources are turned off, the motor is powered off, and the red indicator light goes out. The entire reset process is completed within 2.8 to 3.2 seconds with minimal impact.

[0287] In other embodiments, the electronic controller for the electric seat of this aircraft mainly includes a seat control box, a seat control panel, a USB charging interface, a limit switch, and a drive motor. The seat control box is the core of this invention, as it connects the seat control panel, the USB charging interface, the limit switch, and the drive motor.

[0288] The control box mainly consists of a filter circuit, a reverse connection protection circuit, a power supply module, a control circuit, and an overvoltage and overcurrent protection circuit.

[0289] The 28VDC power supply from the machine enters the control box through the seat power socket. After passing through a filter, it is split into two paths. One path powers the motor drive components, while the other path passes through a filter circuit to remove power supply noise. The 28VDC power supply after the filter circuit enters the power board, which mainly performs reverse connection protection, surge protection, and transient suppression functions. It can disconnect the subsequent 28VDC output if the positive and negative terminals of the power supply are reversed.

[0290] The power board is equipped with two power modules: 5VDC power module 1 and 5VDC power module 2. 5VDC power module 1 primarily provides power to the control circuitry. 5VDC power module 2 primarily provides power to the operation panel, indicator lights, and isolation circuitry.

[0291] The power module outputs 5V to the mainboard control circuit. The control circuit signal is connected to the operation panel via a cable. The button switch circuit on the panel corresponds to the seat adjustment of various postures and one-key reset. The signal is then returned to the control box via a cable and finally output to the motor drive component.

[0292] The control panel is usually installed on the armrest of the seat to detect user button signals and has indicator lights.

[0293] USB charging ports are typically installed on the armrests of seats to provide users with Type-A charging functionality.

[0294] The mainboard control circuit includes an input / output optocoupler isolation circuit, a logic signal drive circuit, an anti-accidental touch circuit, and a limit signal recognition circuit. The optocoupler isolation circuit isolates the control box input and output from the outside, improving the overall electromagnetic compatibility performance. The logic signal drive circuit uses logic gate circuits to realize the detection and control functions of key signals, and also realizes the power cut-off control when the key is accidentally touched. It can also detect and cut off the user key input when the seat reaches the limit position of the travel to prevent the motor from stalling.

[0295] After the logic control signal passes through the input optocoupler isolation circuit, it is used to detect the key signal through a combination circuit of AND gate chip and NOT gate chip, and then sent to the output optocoupler isolation circuit to provide the motor drive component with the corresponding stroke operation. At the same time, the working status of the limit switch is monitored throughout the process, and the power supply protection circuit is immediately cut off when the limit signal is triggered. The key anti-accidental touch function is implemented by AND gate and MOS circuit to cut off the input function when the user accidentally touches the key. The one-key reset function of all seat postures is implemented by D latch and delay circuit.

[0296] System working principle: After the system is powered on, the operation panel monitors the button signals in real time. When a button is pressed, the signal enters the control unit and is sent to the motor drive unit. The motor travel rod is driven at a set speed to change the seat posture accordingly. When the button signal disappears, the drive motor immediately stops moving and locks in the current position. When a one-key reset is pressed, the control unit resets all motors, thereby restoring the seat posture.

[0297] By adopting the above-disclosed technical solution of this invention, the following beneficial effects are obtained:

[0298] This invention discloses a method for implementing control logic for an aircraft electric seat, the effects of which are:

[0299] High reliability: All control functions are implemented using pure hardware logic gate circuits, completely eliminating the risk of software bugs; the hardware interlock circuit cuts off the motor power supply in less than 1ms to avoid stalling.

[0300] Low maintenance costs: No software burning, debugging and version management are required, and modules can be directly interchanged, reducing the cost of aircraft parts turnover and manual maintenance.

[0301] High compatibility: 28V aviation DC input, built-in reverse connection protection, surge protection, EMI filtering, meets DO-160G requirements, and can directly replace existing imported controllers.

[0302] Excellent user experience: The one-button reset function can complete the return of the entire attitude to zero within 3 seconds; the USB-A5V / 1.5A charging port meets the charging needs of pilots' electronic devices.

[0303] Compact structure: integrated aluminum alloy shell, IP54 protection, single-sided cable exit, weight <450g, easy to install on the side armrest of the seat.

[0304] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. An electronic controller for an aircraft electric seat, characterized in that, include: Seat control box, the seat control box having: The filter circuit is used to filter the 28V DC input on the machine. The reverse connection protection and surge protection circuit is electrically connected to the filter circuit and automatically disconnects the output when the positive and negative terminals of 28V DC are reversed. The first power module is used to convert 28V DC to 5V DC to power the control circuit. The second power module is used to convert 28V DC to a second 5V DC to power the seat control panel, indicator lights and isolation circuit. The seat control panel, installed on the seat armrest, has seven buttons: backrest forward, backrest backward, leg rest up, leg rest down, leg rest forward, leg rest backward, and one-button reset. The seat control panel is electrically connected to the second power module and the control circuit. The limit switch assembly includes six attitude limit switches and one ground contact protection limit switch, and the limit switch assembly is electrically connected to the control circuit. The drive motor assembly includes three DC motors with Hall sensors, which are used to drive the seat back back forward and backward, the leg support forward and backward, and the leg support extension and retraction, respectively. The drive motor assembly is electrically connected to the control circuit. A USB charging module is used to convert 28V DC to USB-A5V output and is installed on the seat armrest; The control circuit includes: Input / output optocoupler isolation circuit; The logic signal driving circuit, composed of AND gate chips, NOT gate chips and MOS circuits, is used to realize key signal detection and motor drive control to prevent accidental touch. Limit signal recognition circuit, used to immediately cut off the motor power supply when any limit switch is triggered; The D latch and delay circuit are used to synchronously reset all motors to their initial position when a one-key reset signal is received.

2. The electronic controller for an aircraft electric seat according to claim 1, characterized in that, The logic signal driving circuit is configured as follows: When any button is pressed, a forward or reverse signal for the motor corresponding to that button is output. When the button is released, the motor drive signal is immediately canceled, causing the motor to stop and maintain its current position; When two or more buttons are pressed simultaneously, all input signals are cut off within 10ms through the combination of the AND gate chip and MOS circuit to prevent accidental touches.

3. The electronic controller for an aircraft electric seat according to claim 2, characterized in that, The limit signal recognition circuit includes: The hardware interlock circuit has a response time of ≤1ms and is used to directly shut down the MOSFET drive stage when any limit switch is triggered. The software redundancy judgment loop is used to make a secondary judgment based on the position signal of the Hall sensor and cut off the motor power supply within 5ms when the hardware interlock loop fails.

4. The electronic controller for an aircraft electric seat according to claim 3, characterized in that, The D latch and delay circuit are configured as follows: A reset command is triggered after the one-key reset button is continuously pressed for more than 500ms. During the reset process, the backrest motor, the front and rear leg support motors, and the extension leg support motor are controlled sequentially according to the preset timing to return to the mechanical origin, and the power is automatically cut off and locked after all motors reach the origin position.

5. The electronic controller for an aircraft electric seat according to claim 4, characterized in that, The USB charging module includes: Synchronous step-down DC-DC converter with an efficiency ≥92%; Output overcurrent, overvoltage and short circuit protection circuit, with overcurrent protection point of 1.5A±10% and overvoltage protection point of 5.6V±2%; The output TVS diode is used to meet the DO-160G aviation electromagnetic compatibility requirements.

6. The electronic controller for an aircraft electric seat according to claim 5, characterized in that, The control circuit and the drive motor assembly are connected by a detachable shielded cable. The shielding layer of the shielded cable is grounded at a single point to the metal shell of the seat control box through a 360° metal pressure ring to reduce electromagnetic interference.

7. The electronic controller for an aircraft electric seat according to claim 6, characterized in that, The control circuit also includes: Motor current sampling circuit, used to detect motor bus current in real time; The stall detection circuit is used to immediately cut off the motor power supply and report a fault signal when the current continuously exceeds the threshold within 50ms after the motor starts and the Hall sensor feedback speed is zero.

8. The electronic controller for an aircraft electric seat according to claim 7, characterized in that, The metal casing of the seat control box is integrally milled from aluminum alloy, and conductive rubber sealing strips are provided at the joints of the casing to achieve an IP54 protection level and electromagnetic shielding effectiveness of ≥60dB@1GHz.

9. A method for implementing control logic for an aircraft electric seat, characterized in that, The following steps are performed using the electronic controller for the aircraft electric seat according to any one of claims 1-8: a) After the system is powered on, it performs a self-test. If any limit switch malfunctions or Hall sensor signal is detected as missing, the motor will be prohibited from starting and a fault indication will be output. b) In normal working mode, the key signals are collected in real time. When a single key press is detected, the corresponding motor drive is executed; when multiple keys are pressed at the same time, the anti-mistouch logic is executed. c) During motor operation, the position signal of the Hall sensor and the status of the limit switch are collected in real time. When any limit switch is triggered, the hardware interlock power is immediately executed. d) When the one-key reset button is continuously pressed for more than 500ms, the system enters the reset mode and controls each motor to return to the mechanical origin according to the preset timing sequence. e) After the reset is complete, power off and lock all motors, and turn off the fault indicator lights.

10. The method according to claim 9, characterized in that, The reset timing in step d) includes: First, control the backrest motor to return to the origin at the first speed; Then control the front and rear motors of the leg support to return to the origin at the second speed; Finally, control the leg support telescopic motor to return to the origin at the third speed; The first, second, and third speeds decrease sequentially to avoid mechanical impact and reduce the total reset time.

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