Performance test system for nose landing gear

Abstract

The invention discloses a nose landing gear performance testing system, which relates to the field of aircraft testing and comprises an upper computer, a lower computer PLC (Programmable Logic Controller) and a hydraulic control module, the upper computer is used for sending the take-up and pay-off speed curve and the angle displacement value to the lower computer PLC; the hydraulic control module comprises an oil source module, an angular displacement sensor and a proportional reversing valve; the angular displacement sensor is used for acquiring the rotation angles of the turning actuating cylinder and the retracting and releasing actuating cylinder, determining the variable quantity of the flow of the corresponding actuating cylinder according to the rotation angles, and converting the variable quantity into an angular displacement value; the lower computer PLC is used for converting the winding and unwinding speed curve and the angle displacement value into an angle control signal and adjusting the angle control signal according to the angle displacement value of the angular displacement sensor; the proportional reversing valve is used for adjusting the proportional angle when receiving the angle control signal so as to control the flow of the retracting and releasing actuator cylinder, the left turning actuator cylinder and the right turning actuator cylinder, and the retracting and releasing action, the left turning action or the right turning action of the nose landing gear at different speeds are carried out.

Description

Technical Field

[0001] This invention relates to the field of aircraft testing technology, and in particular to a nose landing gear performance testing system. Background Technology

[0002] The nose landing gear is a crucial component of an aircraft, and its performance directly impacts the safety and reliability of takeoff, landing, and taxiing. In actual operation, the nose landing gear must withstand varied and extreme conditions, such as the movement of actuators at different speeds (e.g., low-speed taxiing, high-speed turning), to test key performance aspects like turning and retraction under various conditions. Traditional testing equipment struggles to fully simulate these complex conditions, leading to discrepancies between test results and actual usage, and making it impossible to accurately assess the nose landing gear's performance. Summary of the Invention

[0003] This invention provides a nose landing gear performance testing system to solve the above-mentioned problems existing in the prior art, namely, how to improve the accuracy of aircraft nose landing gear performance simulation in the prior art. This invention provides a nose landing gear performance testing system, including a host computer, a slave PLC and a hydraulic control module. The host computer is used to send the preset take-up and take-down speed curve and angular displacement value to the slave computer PLC; The hydraulic control module includes an oil source module, an angular displacement sensor, and a proportional directional valve. The angular displacement sensor is electrically connected to the turning actuator and the retracting actuator, respectively, and is used to acquire the rotation angle of the turning actuator and the retracting actuator in real time. Based on the rotation angle, the change in flow rate of the corresponding turning actuator and the retracting actuator is determined, and the change in flow rate is converted into an angular displacement value. The turning actuator includes a left-turning actuator and a right-turning actuator. The lower-level PLC is used to convert the preset take-up and release speed curve and angular displacement value into an angle control signal, and adjust the angle control signal in real time according to the angular displacement value of the angular displacement sensor. The proportional directional valve is connected to the oil source module, the turning actuator, and the retraction / extension actuator via pipeline connections. When the proportional directional valve receives an angle control signal from the lower-level PLC, it adjusts the proportional angle to control and regulate the flow of the retraction / extension actuator, the left-turn actuator, and the right-turn actuator of the front landing gear, so as to perform retraction / extension, left-turn, or right-turn actions of the front landing gear at different speeds.

[0004] It also includes a monitoring module, which is connected to the host computer and includes a test control module, a communication module, and a status monitoring module; The test control module includes a data acquisition module and an output control module, used to acquire instructions from the host computer and determine the status information of each channel; The communication module is used to upload the test data collected by the data acquisition module to the host computer; The status monitoring module is used to analyze the instructions from the host computer and compare the collected test data with the preset out-of-tolerance parameters. When the test data exceeds the preset out-of-tolerance parameters, the test is stopped.

[0005] Optionally, the hydraulic control module further includes a proportional relief valve, which is connected to the oil source module, the turning actuator, and the retraction / extension actuator via pipeline connections. The proportional directional valve is used to adjust its opening when it receives a pressure control signal from the lower-level PLC, so as to control and regulate the pressure of the retraction / extension actuator, the left-turn actuator, and the right-turn actuator of the front landing gear, so as to perform retraction / extension, left-turn, or right-turn actions of the front landing gear under different loads.

[0006] Optionally, the hydraulic control module adopts an integrated valve block design. The hydraulic control module has two operating modes: manual mode and automatic mode. In manual mode, it is operated via physical buttons, and in automatic mode, it is controlled by a host computer. The host computer is a touch screen.

[0007] Optionally, the hydraulic control module is equipped with a high-pressure replenishing pump and a hand-cranked pump for sealing tests and emergency operations.

[0008] It also includes a jig module, which is used to position the nose landing gear using digital signal transmission and laser testing technology, and to mount the nose landing gear on the test bench.

[0009] Compared to existing technologies, the beneficial effects of this invention are as follows: This invention provides a nose landing gear performance testing system. This system receives test commands from a lower-level PLC through multiple proportional directional valves in a hydraulic control module, adjusts the opening of the proportional directional valves, thereby precisely controlling the flow and direction of hydraulic oil. This allows for the simulation of actuator movement at different speeds, such as low-speed taxiing or high-speed turning, to accurately simulate the turning and retraction movements of the nose landing gear at different speeds. Simultaneously, this invention feeds back the angular displacement values ​​obtained by angular displacement sensors to the lower-level PLC in real time, enabling the lower-level PLC to adjust the opening of the proportional directional valves based on the feedback data, forming a closed-loop control. This ensures precise adjustment of the turning angle and speed, further guaranteeing the accuracy of the performance simulation of the aircraft's nose landing gear. Attached Figure Description

[0010] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0011] Figure 1 This is a structural diagram of the nose landing gear performance testing system provided in an embodiment of the present invention; Figure 2 This is a structural block diagram of the monitoring module provided in an embodiment of the present invention; Figure 3 A schematic diagram of a hydraulic control module provided for an embodiment of the present invention. Detailed Implementation

[0012] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0013] The technical solution of the present invention and how the technical solution of the present invention solves the above-mentioned technical problems are described in detail below with specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments. The embodiments of the present invention will now be described with reference to the accompanying drawings.

[0014] Figure 1 This is a structural diagram of the nose landing gear performance testing system provided in an embodiment of the present invention, as shown below. Figure 1 As shown in this embodiment, a front landing gear performance testing system includes a host computer, a slave PLC, and a hydraulic control module. The host computer sends preset retraction / extension speed curves and angular displacement values ​​to the slave PLC. The hydraulic control module includes an oil source module, an angular displacement sensor, and a proportional directional valve. The angular displacement sensor is electrically connected to both the turning actuator and the retraction / extension actuator, and is used to acquire the rotation angles of the turning actuator and the retraction / extension actuator in real time. Based on the rotation angle, the system determines the corresponding change in flow rate of the turning actuator and the retraction / extension actuator, and converts the change in flow rate into an angular displacement value. The turning actuator includes a left-turning actuator. The system includes a right-turn actuator; the lower-level PLC converts the preset retraction / extension speed curve and angular displacement value into an angle control signal, and adjusts the angle control signal in real time according to the angular displacement value of the angular displacement sensor; the proportional directional valve is connected to the oil source module, the turning actuator, and the retraction / extension actuator via pipeline connection; the proportional directional valve is used to adjust the proportional angle when it receives the angle control signal from the lower-level PLC, so as to control and regulate the flow of the retraction / extension actuator, the left-turn actuator, and the right-turn actuator of the front landing gear, so as to perform retraction / extension, left-turn, or right-turn actions at different speeds of the front landing gear.

[0015] For example, the host computer can be a touchscreen, and the lower-level PLC can communicate with the touchscreen using the RS485 serial communication protocol. The system considers the touchscreen's interface with the field communication bus, enabling remote control of the test bench, user program download, and data sharing. The selected touchscreen has a color printer connection interface for printing test reports. During the retraction and rotation tests, the control signal of the proportional control valve is adjusted online via the rotary button on the host computer's touchscreen, and this signal is sent to the lower-level PLC. The PLC controls the proportional valve's proportional reversal based on the control signal. During pressure adjustment, the pressure is set via the touchscreen mounted on the electrical control console, and the set value is then transmitted to the PLC for automatic control. Furthermore, the PLC detects the pump station's outlet pressure and controls the frequency converter to form a closed-loop control, thus constituting the automatic control of the pump station.

[0016] For example, the present invention adopts a direct cooling method, which uses data fed back by temperature sensors and temperature controllers to draw hydraulic oil in the oil tank into an oil cooler for cooling through an oil pump. The cooled oil then enters the oil tank, and this cycle is repeated to reduce the overall temperature inside the oil tank.

[0017] like Figure 2 As shown, the lower-level PLC includes an initialization module, a test control module, a communication module, and a status monitoring module. The initialization module is used for hardware initialization, instruction initialization, and control rate and parameter initialization. The test control module includes a data acquisition module and an output control module, used to acquire instructions from the upper-level computer and the status information of each channel through the status monitoring module. The communication module is used to upload the test data acquired by the data acquisition module to the upper-level computer. The status monitoring module is used to analyze the instructions from the upper-level computer and compare the acquired test data with the preset out-of-tolerance parameters. When the test data exceeds the preset out-of-tolerance parameters, the test is stopped and the upper-level computer is notified to stop running.

[0018] For example, the retraction and extension speed of the nose landing gear can be controlled by a proportional directional valve, the pressure output can be controlled by a proportional relief valve, and the flow rates of the nose landing gear's turning and retraction actuators are controlled by a frequency converter to achieve closed-loop control of the pump station motor speed; wherein, the pressure control cycle frequency is higher than 1KHz, and the flow control cycle frequency is higher than 1KHz. The analog signal acquisition channel has a data accuracy of 12 bits, and the sampling frequency is greater than 10K / s when all channels are working simultaneously. The PLC communicates with the industrial control computer via a 485 communication cable.

[0019] For example, the test control module is the core part of the lower-level software, responsible for completing the closed-loop control of each take-up and release channel. It obtains management commands from the touchscreen through the status monitoring module, thereby enabling functions such as starting or stopping the test, self-checking, or calibration. During the test, the test control module automatically tracks the status of each channel, promptly acquiring status information and adjusting it using appropriate control laws to ensure the accuracy requirements of the test system. The test control module includes a data acquisition module and an output control module. The data acquisition module is mainly responsible for collecting the status parameters of each channel. Besides being used for signal characteristic quantity calculation and test control quantity calculation, the data collected by this module is transmitted to the upper-level computer via the communication module for storage and processing. The output control submodule outputs control signals based on the control quantities calculated by the control decision function, controlling external proportional valves to achieve closed-loop control of the entire channel.

[0020] For example, the number of lower-level PLCs selected ensures that the CPU module of the PLC system has an expansion margin of over 30% for the number of system I / O points (including digital channels, analog channels, etc.), with 30% spare ports reserved for both digital and analog channels; over 30% spare space is reserved for program storage, and 40% spare space is reserved for data storage; expansion space is reserved for at least two analog input modules, and expansion space is reserved for one analog output module. The retraction and expansion speed is controlled by a proportional directional valve, the pressure by a proportional relief valve, and the flow rate is controlled by a frequency converter to control the pump station motor speed, achieving closed-loop control. The pressure control cycle frequency is higher than 1kHz, and the flow control cycle frequency is higher than 1kHz. The analog acquisition channel has a data precision of 12 bits, and the sampling frequency is greater than 10K / s when all channels are working simultaneously. Communication between the PLC and the touch screen is via an RS485 communication cable.

[0021] For example, the communication module of the lower-level machine uploads the test data collected by the data acquisition module to the upper-level machine. In this embodiment, the lower-level machine can be a touch screen for display and data storage by the graphical user interface of the upper-level machine. Simultaneously, this data is also provided to the status monitoring module for test status analysis, and the test is stopped when an abnormality occurs.

[0022] For example, the status monitoring module comprises two parts: upper computer management command analysis and processing, and test mechanism status analysis. Upper computer management command analysis and processing refers to the calculation and analysis of intervention commands transmitted from the upper computer. Because RS485 transmits commands digitally, different status bits represent different intervention commands; therefore, logical operations must be performed on each status bit to obtain the upper computer's intervention command. Test mechanism status analysis compares the collected test data with the system-set out-of-tolerance parameters. If the actual test data exceeds the set parameters, the software will automatically stop the test process and notify the upper computer to also stop running.

[0023] For example, the hydraulic control module includes an oil source module and a test bench oil circuit module. The oil source module may include three parts: a power unit, a pressure control unit, and an auxiliary unit. The main components of the oil source module include a motor and motor starter cabinet, a fixed displacement pump, an oil filter, a proportional relief valve, a manual relief valve with electromagnetic unloading, an oil cooler, and an oil tank. The components in the pressure control unit and auxiliary unit are connected by a plate and mounted on the oil source valve block. The oil source module is small in size and has few pipelines.

[0024] like Figure 3 The diagram shows the schematic of the hydraulic control module. A proportional directional valve can be used for the landing gear retraction test, forming a closed-loop control system with a proximity switch. The proximity switch sends a position signal, and the proportional directional valve 1 controls the speed of the retraction / retraction actuator and the locking actuator, thereby driving the landing gear to perform retraction / retraction and locking movements at different speeds. For example, the landing gear lowering and retraction actions can be controlled by a solenoid valve. The workflow can be as follows: 1. Lowering the landing gear: The pilot or automatic system issues a command to lower the landing gear; solenoid valve 1 is energized, hydraulic oil enters the lowering side of the retraction / retraction actuator, pushing the piston to extend the actuator, gradually lowering the landing gear. When the landing gear reaches the lowered position, the locking actuator locks it, ensuring the landing gear remains in the lowered position. 2. Retracting the landing gear. The pilot or automatic system issues a command to lower the landing gear; solenoid valve 1 is de-energized, hydraulic oil enters the retraction side of the retraction actuator, pushing the piston to retract the actuator, causing the landing gear to gradually retract. When the landing gear reaches the retracted position, the locking actuator locks, ensuring the landing gear remains in the retracted position; the turning test can be performed by proportional directional valves 2 and 3, forming a closed-loop control with the angular displacement sensor to strictly control the turning angle and speed; the PLC controls the frequency converter, and the detection signal of the frequency converter forms a closed-loop control to control the output flow of the pump station; pressure adjustment uses a proportional relief valve, which is installed on the hydraulic control console and can be adjusted manually or automatically. Manual adjustment is performed by the potentiometer on the operation panel, and automatic adjustment is performed by setting the pressure through the touch screen installed on the electrical control console, and then the set value is transmitted to the PLC for automatic control; the lifting mechanism provides support and simulates load for the smooth conduct of subsequent experiments, and the extension and retraction of the piston rod is controlled by the solenoid directional valve.

[0025] For example, the power unit of the oil source module includes a motor and frequency converter, a bell housing and coupling, and an oil pump. Vibration damping rings and damping strips are auxiliary components used to reduce vibration and noise. The bell housing is used to fix the motor and oil pump housings together. The coupling connects the motor shaft and oil pump shaft inside the bell housing. The pressure control unit can use a manual relief valve with electromagnetic unloading and a proportional relief valve connected in parallel to control the output pressure of the pump source. The manual relief valve with electromagnetic unloading can provide emergency unloading and manual pressure adjustment when the proportional relief valve is not working. When the proportional relief valve is working normally, it acts as a safety valve and can also provide emergency unloading, protecting the system. The proportional relief valve is used to achieve remote pressure regulation control and also has manual adjustment / control functions. Auxiliary units include filters, oil tanks, accumulators, and oil coolers. The oil filters include an oil inlet filter, an oil return filter, and a high-pressure oil filter at the hydraulic pump outlet. All oil filters are equipped with transmitters for contamination monitoring and alarm. In a hydraulic system, the oil tank not only stores hydraulic fluid but also purifies it, maintains its temperature within a certain range, and reduces the amount of air bubbles in the oil in the suction area. Simultaneously, a direct cooling method is used, where the hydraulic oil in the tank is drawn into an oil cooler by an oil pump for cooling. The cooled oil then returns to the tank, and this cycle continues, lowering the overall temperature within the tank.

[0026] For example, the hydraulic control module adopts an integrated valve block design. The hydraulic control module has two operating modes: manual mode and automatic mode. In manual mode, it is operated by physical buttons, and in automatic mode, it is controlled by a touch screen.

[0027] For example, the hydraulic control module can be designed using an integrated valve block, which can be divided into an oil source valve block and a control valve block. The integrated valve block can be plated with nickel-chromium alloy, and the surface roughness of the assembly can be selected as 0.8 to ensure a leak-proof seal after assembly. All pipeline materials can be made of 1Cr18Ni9Ti, and flanges, joints, fasteners, etc., can be made of high-quality stainless steel. The conduits on the test bench can be installed straight to minimize the number of pipe bends. The hydraulic hard conduits and oil tank can be made of stainless steel; the conduit connection can be a flared connection, and all pipe fittings can be galvanized; all parts can be galvanized and painted; the hydraulic control module can also absorb hydraulic shocks and pressure pulsations in various ways, and the peak hydraulic shock pressure does not exceed the rated value.

[0028] For example, the hydraulic control module is equipped with a high-pressure replenishing pump and a hand-cranked pump for sealing tests and emergency operations. The hydraulic control module includes system safety controls, with a manual relief valve, a proportional relief valve, and a manual shut-off valve connected in parallel between the pump's outlet and the system return line. This allows for both manual and electronic unloading, ensuring that the system pressure is controlled within a safe range.

[0029] For example, the frame module can be made of high-strength steel, and stress concentration problems can be reduced by using welding and annealing processes. In addition, the precise installation of the nose landing gear on the frame can be ensured by using laser positioning technology and digital signal transmission method.

[0030] After the test, the lower-level computer can analyze the instructions from the upper-level computer and compare the collected test data with the preset out-of-tolerance parameters. When the test data exceeds the preset out-of-tolerance parameters, the test is stopped and the upper-level computer is notified to stop running. The out-of-tolerance parameters may include, for example, the retraction speed, the rotation angle range, and the pressure value.

[0031] For example, the main test indicators for the performance testing of the nose landing gear of the present invention are as follows: (1) Pressure range: 0~21MPa (continuously adjustable); (2) Oil supply flow rate: Plunger pump: Q=21L / min, frequency conversion adjustable flow rate; Manual pump displacement: 15cm3 / time; Retraction and extension time: 7~15 seconds adjustable; (3) Working medium: No. 15 aviation hydraulic oil / GJB1177-1991; Working medium contamination level: better than level 6 specified in GJB420B-2006; Filter accuracy: 10um; (4) Temperature range: Test environment temperature: -5℃~+55℃; Working fluid temperature: +20℃-+55℃.

[0032] (5) The design and manufacture of this test bench shall conform to ISO international standards.

[0033] (6) The units of measurement for all parts, components and instruments of this test bench can be in accordance with the International Units (SI) standard.

[0034] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this invention.

Claims

1. A nose landing gear performance testing system, characterized in that, Includes a host computer, a slave PLC, and a hydraulic control module; The host computer is used to send the preset take-up and take-down speed curve and angular displacement value to the slave computer PLC; The hydraulic control module includes an oil source module, an angular displacement sensor, and a proportional directional valve. The angular displacement sensor is electrically connected to the turning actuator and the retracting actuator, respectively, and is used to acquire the rotation angle of the turning actuator and the retracting actuator in real time. Based on the rotation angle, the change in flow rate of the corresponding turning actuator and the retracting actuator is determined, and the change in flow rate is converted into an angular displacement value. The turning actuator includes a left-turning actuator and a right-turning actuator. The lower-level PLC is used to convert the preset take-up and release speed curve and angular displacement value into an angle control signal, and adjust the angle control signal in real time according to the angular displacement value of the angular displacement sensor. The proportional directional valve is connected to the oil source module, the turning actuator, and the retraction / extension actuator via pipeline connections. When the proportional directional valve receives an angle control signal from the lower-level PLC, it adjusts the proportional angle to control and regulate the flow of the retraction / extension actuator, the left-turn actuator, and the right-turn actuator of the front landing gear, so as to perform retraction / extension, left-turn, or right-turn actions of the front landing gear at different speeds.

2. The nose landing gear performance testing system as described in claim 1, characterized in that, It also includes a monitoring module, which is connected to the host computer and includes a test control module, a communication module, and a status monitoring module; The test control module includes a data acquisition module and an output control module, used to acquire instructions from the host computer and determine the status information of each channel; The communication module is used to upload the test data collected by the data acquisition module to the host computer; The status monitoring module is used to analyze the instructions from the host computer and compare the collected test data with the preset out-of-tolerance parameters. When the test data exceeds the preset out-of-tolerance parameters, the test is stopped.

3. The nose landing gear performance testing system as described in claim 1, characterized in that, The hydraulic control module also includes a proportional relief valve, which is connected to the oil source module, the turning actuator, and the retraction / extension actuator via pipeline connections. The proportional directional valve is used to adjust the opening degree when it receives a pressure control signal from the lower-level PLC, so as to control and regulate the pressure of the retraction / extension actuator, the left-turn actuator, and the right-turn actuator of the front landing gear, so as to perform retraction / extension, left-turn, or right-turn actions of the front landing gear under different loads.

4. The nose landing gear performance testing system as described in claim 1, characterized in that, The hydraulic control module adopts an integrated valve block design. The hydraulic control module has two operating modes: manual mode and automatic mode. In manual mode, it is operated by physical buttons, and in automatic mode, it is controlled by a host computer. The host computer is a touch screen.

5. The nose landing gear performance testing system as described in claim 1, characterized in that, The hydraulic control module is equipped with a high-pressure replenishing pump and a hand-cranked pump for sealing tests and emergency operations.

6. The nose landing gear performance testing system as described in claim 1, characterized in that, It also includes a jig module, which is used to position the nose landing gear using digital signal transmission and laser testing technology, and to mount the nose landing gear on the test bench.

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