Airplane brake control method and system based on energy deviation and deviation change

Abstract

The application is a kind of airplane brake control method and system based on energy deviation and deviation change, belonging to the technical field of airplane brake control; the method steps include: calculating airplane landing energy; calculating airplane landing energy deviation, and quantitatively classifying landing energy deviation; calculating first brake airplane energy and first brake energy deviation; calculating the deviation change of first brake energy deviation and landing energy deviation, and quantitatively classifying the deviation change; determining brake reference pressure according to airplane landing energy deviation and deviation change, and completing self-adaptive adjustment of brake pressure under different airplane landing configurations. The application determines the reference pressure of this stage brake control according to energy deviation E and energy deviation EC, realizes airplane brake control based on energy deviation and deviation change, completes self-adaptive control of airplane brake, fully develops brake efficiency, and improves brake efficiency.

Description

Technical Field

[0001] This invention belongs to the field of aircraft braking control technology, specifically relating to an aircraft braking control method and system based on energy deviation and deviation changes. Background Technology

[0002] The aircraft landing braking process is an energy conversion process, primarily involving the conversion of kinetic energy into heat energy through friction on the brake discs. Braking torque is a core factor in conversion efficiency. Under the same braking pressure, the magnitude of the braking torque is related to the coefficient of friction, which in turn is related to multiple factors such as brake temperature, braking speed, and brake materials, exhibiting a multi-faceted and non-linear relationship. The coefficient of friction is significantly affected by brake temperature; the higher the temperature, the lower the coefficient of friction. Therefore, under the condition that other factors remain constant, controlling the changes in braking torque caused by brake temperature is extremely important.

[0003] The main factor affecting brake temperature is the change in brake energy. The greater the energy, the higher the temperature within the rated time. Therefore, the braking torque for high-energy landings differs significantly from that for normal landings. Aircraft landing configurations are generally categorized into normal landing with parachute deployed, normal landing without parachute deployed, maximum landing with parachute deployed, maximum landing without parachute deployed, and aborted takeoff configurations, each with significant energy differences.

[0004] Conventional braking control methods, which use rated braking pressure, cannot recognize different landing brake configurations. This results in high torque during low-energy states like normal landing with parachute deployment, making skidding more likely, while low torque during high-energy states like maximum landing without parachute deployment leads to poor deceleration and a higher risk of runway overrun. Clearly, whether or not the drag chute deploys during braking significantly impacts braking energy.

[0005] Conventional braking control methods have the following drawbacks:

[0006] 1. It cannot identify braking energy based on mass and speed, resulting in low rated braking efficiency and low safety;

[0007] 2. It cannot identify speed and drag chute status in real time, nor can it recognize energy change trends; the control is simplistic and inaccurate. Conventional anti-skid braking control methods rely on rated braking pressure and anti-skid control. Under most operating conditions, the wheel well capacity ensures that the aircraft meets most operational requirements. However, in extreme high-energy situations, conventional anti-skid braking control methods cannot guarantee that the aircraft will not overrun the runway. Identifying aircraft energy deviation and its changes, based on aircraft data and a braking database, is a process of moving from fuzzy to clear analysis; the algorithm is complex and challenging. Summary of the Invention

[0008] The technical problem to be solved:

[0009] To overcome the shortcomings of existing technologies, this invention provides an aircraft braking control method based on energy deviation and its changes. A database of the aircraft's dominant energy state is established, where the dominant state represents the aircraft's normal landing load (a landing configuration in most cases). The dominant energy state is the kinetic energy of the aircraft under normal landing load. Energy deviation E is calculated based on the energy after landing and the dominant energy database. During braking, during the pressure build-up process, the energy deviation EC is calculated again based on the aircraft's mass, speed, and drag chute status. The reference pressure for braking control in this stage is determined based on the energy deviation E and energy deviation EC, realizing aircraft braking control based on energy deviation and its changes. This achieves adaptive control of the aircraft braking, fully utilizing braking performance and improving braking efficiency.

[0010] The technical solution of this invention is: an aircraft braking control method based on energy deviation and deviation changes, the specific steps of which are as follows:

[0011] Calculate the aircraft's landing energy;

[0012] Calculate the aircraft landing energy deviation and quantify and classify the landing energy deviation;

[0013] Calculate the initial braking energy of the aircraft and the initial braking energy deviation;

[0014] Calculate the variation of the initial braking energy deviation and the landing energy deviation, and quantify and classify the variation of the deviation;

[0015] The braking reference pressure is determined based on the aircraft landing energy deviation and deviation changes, and the braking pressure is adaptively adjusted for different aircraft landing configurations.

[0016] A further technical solution of the present invention is: the calculation formula for the aircraft landing energy Q0 is as follows:

[0017] Q0 = 0.5mv 2 (1)

[0018] In the formula, m is the mass of the aircraft, and v is the speed of the aircraft when it lands.

[0019] A further technical solution of the present invention is: the calculation formula for the aircraft landing energy deviation E0 is as follows:

[0020] E0 = Q0 - Q K (2)

[0021] In the formula, Q K It is energy data in the main state energy database.

[0022] A further technical solution of the present invention is as follows: the quantitative classification of the aircraft landing energy deviation includes negative large (NB), negative medium (NM), negative small (NS), zero (Z), positive small (PS), positive medium (PM), and positive large (PB). The negative large (NB) value is an energy negative deviation greater than -5MJ; the negative medium (NM) value is an energy negative deviation between -5MJ and -3MJ; the negative small (NS) value is an energy negative deviation between -3MJ and -1MJ; the zero (Z) value is an energy deviation between -1MJ and 1MJ; the positive small (PS) value is an energy positive deviation between 1MJ and 3MJ; the positive medium (PM) value is an energy positive deviation between 3MJ and 5MJ; and the positive large (PB) value is an energy positive deviation greater than 5MJ.

[0023] A further technical solution of the present invention is: the calculation formula for the initial braking energy Q1 of the aircraft is as follows:

[0024] Q1 = 0.5mv1 2 (1)

[0025] In the formula, m is the mass of the aircraft, and v1 is the speed of the aircraft when it first brakes.

[0026] A further technical solution of the present invention is: the calculation formula for the initial braking energy deviation E1 is as follows:

[0027] E1 = Q1 - Q K (2)

[0028] In the formula, Q K It is energy data in the main state energy database.

[0029] A further technical solution of the present invention is: the formula for calculating the deviation change EC0 between the initial braking energy deviation and the landing energy deviation is as follows:

[0030] EC0 = E1 - E0 (3)

[0031] A further technical solution of the present invention is as follows: the quantitative classification of the deviation change includes negative large NB', negative medium NM', negative small NS', zero Z', positive small PS', positive medium PM', and positive large PB'. Negative large NB' is defined as an energy negative deviation greater than -5MJ; negative medium NM' is defined as an energy negative deviation between -5MJ and -3MJ; negative small NS' is defined as an energy negative deviation between -3MJ and -1MJ; zero Z' is defined as an energy deviation between -1MJ and 1MJ; positive small PS' is defined as an energy positive deviation between 1MJ and 3MJ; positive medium PM' is defined as an energy positive deviation between 3MJ and 5MJ; and positive large PB' is defined as an energy positive deviation greater than 5MJ.

[0032] A further technical solution of the present invention is: the determination of the brake reference pressure is completed according to the brake reference pressure rule table, which is as follows:

[0033]

[0034] Wherein, P is the reference pressure under the dominant state with no energy deviation or deviation change, and the unit is MPa.

[0035] An aircraft braking control system based on energy deviation and deviation variation includes a braking unit for applying and adaptively adjusting braking pressure to the wheels; a sensor unit mounted on the wheels for detecting the rotational speed and load of the wheels; a control unit for acquiring signals from the sensor unit and the computing unit and issuing control commands to the braking unit; and a computing unit for performing calculations in the aircraft braking control method based on energy deviation and deviation variation.

[0036] An aircraft includes a fly-by-wire anti-skid braking system, wherein the fly-by-wire anti-skid braking system employs an aircraft braking control method based on energy deviation and deviation changes to achieve adaptive control of the aircraft braking.

[0037] Beneficial effects

[0038] The beneficial effects of this invention are as follows: This invention achieves braking control of aircraft based on energy state, determines the braking reference pressure through energy deviation E and deviation change EC, and realizes adaptive adjustment of braking pressure under different aircraft landing configurations, achieving efficient and safe braking, fully utilizing braking capacity, and significantly improving braking efficiency. Conventional anti-skid braking control methods do not recognize braking energy state, have poor adaptability, and low safety.

[0039] Experiments show that under maximum landing load, the brake disc braking torque is low. Conventional braking control methods use rated braking pressure, and the braking torque cannot be adjusted, resulting in a long braking distance. This invention enables adjustment of the braking pressure, thereby increasing the braking torque and effectively shortening the braking distance. Under light landing load, or after the use of aerodynamic deceleration measures, the brake disc braking torque is high. Conventional braking control methods use rated braking pressure, and the braking torque cannot be adjusted, causing repeated wheel slippage and again resulting in a long braking distance. This invention enables adjustment of the braking pressure, thereby reducing the braking torque and effectively shortening the braking distance.

[0040] This invention correlates energy with brake disc torque and captures the optimal combination point between braking torque and ground torque by measuring energy deviation E and deviation change EC, thereby achieving high-efficiency braking. Attached Figure Description

[0041] Figure 1 This is a flowchart of the aircraft braking control method based on energy deviation and deviation changes according to the present invention. Detailed Implementation

[0042] The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the invention, and should not be construed as limiting the invention.

[0043] Existing technologies using rated braking pressure for braking control cannot identify different aircraft landing braking configurations. This leads to problems such as high torque and slippage in low-energy states (e.g., normal landing with parachute deployment) under rated braking pressure, and low torque and poor deceleration in high-energy states (e.g., maximum landing without parachute deployment), resulting in runway overrun. This invention provides an aircraft braking control method and system based on energy deviation and its changes. The method first establishes a database of the aircraft's dominant energy state, which represents the normal landing load. The dominant energy state is the kinetic energy of the aircraft under normal landing load. Energy deviation E is calculated based on the energy after landing and the dominant energy database. During braking, during pressure build-up, energy deviation EC is calculated again based on the aircraft's mass, speed, and parachute status. The reference pressure for braking control in this stage is determined based on energy deviation and its changes, enabling adaptive adjustment of braking pressure under different aircraft landing configurations, achieving efficient and safe braking; fully utilizing braking performance and improving braking efficiency. The dominant state refers to the aircraft landing configuration in most cases.

[0044] This embodiment is a control method based on an anti-skid braking system. The anti-skid braking system is applicable to fly-by-wire anti-skid braking systems. The specific steps of the aircraft braking control method based on energy deviation and deviation changes are as follows:

[0045] Step 1: Calculation of aircraft landing energy Q0

[0046] Immediately after the aircraft lands, the landing energy Q0 is calculated according to formula (1).

[0047] Q = 0.5mv 2 (1)

[0048] In formula (1), m is the mass of the aircraft and v is the speed of the aircraft.

[0049] This step calculates the landing energy Q0. Considering the deviation from the main state energy at the same aircraft speed, this step serves as the basis for calculating the aircraft landing energy deviation E0 in step two.

[0050] Step 2: Calculation and Quantitative Classification of Aircraft Landing Energy Deviation E0

[0051] The energy deviation E0 is calculated using formula (2).

[0052] E = QQ K (2)

[0053] Q in formula (2) K This refers to the energy data in the main state energy database. The main state energy database defines energy data at different speeds. The quantization classification refers to comparing the data with values ​​in the database, quantizing them into seven states from the largest negative deviation to the largest positive deviation. The landing energy Q0 calculated in step one is compared with the energy at the same speed in the energy database using formula (2) to calculate the energy deviation. Then, the energy deviation E0 is quantified and classified into one of the following states: {large negative NB, medium negative NM, small negative NS, zero Z, small positive PS, medium positive PM, large positive PB}. The large negative NB generally has a negative energy deviation greater than -5MJ; the medium negative NM generally has a negative energy deviation between -5MJ and -3MJ; the small negative NS generally has a negative energy deviation between -3MJ and -1MJ; the zero Z generally has an energy deviation between -1MJ and 1MJ; the small positive PS generally has a positive energy deviation between 1MJ and 3MJ; the medium positive PM generally has a positive energy deviation between 3MJ and 5MJ; and the large positive PB generally has a positive energy deviation greater than 5MJ.

[0054] Step 3: Calculation of initial braking energy Q1 and initial braking energy deviation E1.

[0055] During the first braking, the aircraft energy Q1 is calculated according to formula (1); the energy deviation E1 is calculated according to formula (2).

[0056] This step calculates the initial braking energy Q1 of the aircraft. Due to the influence of nonlinear factors such as whether the drag chute is deployed, the aircraft attitude, and aerodynamic deceleration, the initial braking energy deviation E1 and the landing energy deviation E0 may vary. This step serves as the basis for calculating the deviation change EC0 in step four.

[0057] Step 4: Calculation and classification of deviation change EC0

[0058] The deviation change EC0 is calculated using formula (3).

[0059] EC = E1 - E0 (3)

[0060] Based on the calculation results of the deviation change EC0, the deviation change EC is quantitatively classified into one of the following states: {Negative Large NB', Negative Medium NM', Negative Small NS', Zero Z', Positive Small PS', Positive Medium PM', Positive Large PB'}. This step mainly identifies the influence of nonlinear factors such as whether the drag chute is deployed, aircraft attitude, and aerodynamic deceleration on braking energy, thereby correcting the braking reference pressure. The negative large NB' generally has a negative energy deviation greater than -5MJ; the negative medium NM' generally has a negative energy deviation between -5MJ and -3MJ; the negative small NS' generally has a negative energy deviation between -3MJ and -1MJ; the zero Z' generally has an energy deviation between -1MJ and 1MJ; the positive small PS' generally has a positive energy deviation between 1MJ and 3MJ; the positive medium PM' generally has a positive energy deviation between 3MJ and 5MJ; and the positive large PB' generally has a positive energy deviation greater than 5MJ.

[0061] Step 5: Determine the brake reference pressure

[0062] Based on the energy deviation E0 obtained in step two and the deviation change EC0 obtained in step four, the brake reference pressure is determined using Table 1. The reference pressure under the dominant state with no energy deviation or deviation change is typically taken as 8MPa to 10MPa.

[0063] Table 1. Rules for determining brake reference pressure based on energy deviation E0 and deviation change EC0 (unit: MPa)

[0064]

[0065] This embodiment discloses an aircraft braking control system based on energy deviation and deviation changes, including a braking unit for applying and adaptively adjusting braking pressure to the wheels; a sensor unit mounted on the wheels for detecting the rotational speed and load of the wheels; a control unit for acquiring signals from the sensor unit and the computing unit and issuing control commands to the braking unit; and a computing unit for performing calculations in the aircraft braking control method based on energy deviation and deviation changes.

[0066] The above technical solution will be further explained below with reference to specific experiments.

[0067] The steps of the aircraft braking control method based on energy deviation and deviation changes in this embodiment are as follows:

[0068] Step 1: Calculation of aircraft landing energy Q0

[0069] After the aircraft lands, its mass m is 10000kg and its speed v is 300km / h. According to formula (1), the landing energy Q0 is 34.72MJ.

[0070] Step 2: Calculation and Quantitative Classification of Aircraft Landing Energy Deviation E0

[0071] In the main state energy database, the energy at 300km / h is defined as 30MJ. The energy deviation E0 is calculated to be 4.72MJ using formula (2). The energy deviation E0 is quantified and classified as "positive PM".

[0072] Step 3: Calculation of initial braking energy Q1 and initial braking energy deviation E1.

[0073] During the first braking, the aircraft mass m is 10000kg and the aircraft speed v is 240km / h. According to formula (1), the energy Q1 of the aircraft during the first braking is 22.22MJ.

[0074] In the main state energy database, the energy at 240 km / h is defined as 15 MJ, and the energy deviation E1 is calculated to be 7.22 MJ using formula (2).

[0075] Step 4: Calculation and classification of deviation change EC0

[0076] The deviation change EC0 is calculated to be 2.5 MJ using formula (4), and the deviation change EC0 is quantified and classified as "positive PM".

[0077] Step 5: Determine the brake reference pressure

[0078] P is set to 10MPa. Based on the energy deviation E0 obtained in step two and the deviation change EC0 obtained in step four, the brake reference pressure is determined to be 12MPa through Table 1.

[0079] Conventional braking control methods do not adjust the braking pressure and use a maximum braking pressure of 10MPa, resulting in low braking efficiency and long braking distance. The braking control method of the present invention adjusts the braking reference pressure of this embodiment to 12MPa, effectively shortening the braking distance by 210 meters.

[0080] In this embodiment, by selecting the landing configuration, adjusting the aircraft mass and speed, calculating the energy deviation and its change, and determining the braking reference pressure, aircraft braking control based on energy deviation and its change is realized, completing adaptive control of the aircraft braking, fully utilizing braking performance, and improving braking efficiency.

[0081] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention without departing from the principles and spirit of the present invention.

Claims

1. An aircraft braking control method based on energy deviation and deviation variation, characterized in that... The specific steps are as follows: Calculate the aircraft landing energy; the formula for calculating the aircraft landing energy Q0 is as follows: Q0=0.5mv 2 (1) In the formula, m is the mass of the aircraft, and v is the speed of the aircraft when it lands. The aircraft landing energy deviation is calculated and quantified; the formula for calculating the aircraft landing energy deviation E0 is as follows: E0=Q0-Q K (2) In the formula, Q K It is energy data in the main state energy database; The quantitative classification of aircraft landing energy deviation includes negative large (NB), negative medium (NM), negative small (NS), zero (Z), positive small (PS), positive medium (PM), and positive large (PB). Negative large (NB) is defined as an energy deviation greater than -5 MJ; negative medium (NM) is defined as an energy deviation between -5 MJ and -3 MJ; negative small (NS) is defined as an energy deviation between -3 MJ and -1 MJ; zero (Z) is defined as an energy deviation between -1 MJ and 1 MJ; positive small (PS) is defined as an energy deviation between 1 MJ and 3 MJ; positive medium (PM) is defined as an energy deviation between 3 MJ and 5 MJ; and positive large (PB) is defined as an energy deviation greater than 5 MJ. Calculate the initial braking energy of the aircraft and the initial braking energy deviation; Calculate the variation of the initial braking energy deviation and the landing energy deviation, and quantify and classify the variation of the deviation; The braking reference pressure is determined based on the aircraft landing energy deviation and deviation changes, and the braking pressure is adaptively adjusted for different aircraft landing configurations.

2. The aircraft braking control method based on energy deviation and deviation change according to claim 1, characterized in that: The formula for calculating the initial braking energy Q1 of the aircraft is as follows: Q1=0.5mv1 2 (1) In the formula, m is the mass of the aircraft, and v1 is the speed of the aircraft when it first brakes.

3. The aircraft braking control method based on energy deviation and deviation change according to claim 2, characterized in that: The formula for calculating the initial braking energy deviation E1 is as follows: E1=Q1-Q K (2) In the formula, Q K It is energy data in the main state energy database.

4. The aircraft braking control method based on energy deviation and deviation change according to claim 3, characterized in that: The formula for calculating the deviation EC0 between the initial braking energy deviation and the landing energy deviation is as follows: EC0 = E1 - E0 (3).

5. The aircraft braking control method based on energy deviation and deviation change according to claim 4, characterized in that: The quantitative classification of the deviation change EC0 includes negative large NB', negative medium NM', negative small NS', zero Z', positive small PS', positive medium PM', and positive large PB'. The negative large NB' is a value with an energy negative deviation greater than -5MJ; the negative medium NM' is a value with an energy negative deviation between -5MJ and -3MJ; and the negative small NS' is a value with an energy negative deviation between -3MJ and -1MJ. Zero Z' is an energy deviation between -1MJ and 1MJ; positive small PS' is an energy deviation between 1MJ and 3MJ; positive middle PM' is an energy deviation between 3MJ and 5MJ; positive large PB' is an energy deviation greater than 5MJ.

6. The aircraft braking control method based on energy deviation and deviation change according to claim 5, characterized in that: The brake reference pressure is determined according to the brake reference pressure rule table, which is as follows: Wherein, P is the reference pressure under the dominant state with no energy deviation or deviation change, and the unit is MPa.

7. An aircraft braking control system based on energy deviation and deviation variation, characterized in that: The system includes a braking unit for applying and adaptively adjusting braking pressure to the wheels; a sensor unit mounted on the wheels for detecting the rotational speed and load of the wheels; a control unit for acquiring signals from the sensor unit and the computing unit and issuing control commands to the braking unit; and a computing unit for performing calculations in the aircraft braking control method based on energy deviation and deviation changes as described in any one of claims 1-6.

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