An adaptive brake steady deceleration rate adjusting method based on aircraft brake energy

Abstract

The present application relates to the technical field of aircraft anti-skid brake, in particular to a kind of self-adapting brake steady deceleration rate adjusting method based on aircraft brake energy, the method includes obtaining the brake energy state when aircraft starts braking according to aircraft ground speed and aircraft total weight signal;According to the wheel speed and the wheel speed after 1 second, the brake deceleration rate in 1s is obtained;According to the brake energy state when aircraft starts braking and the brake deceleration rate in 1s, brake pressure is adjusted until the wheel steady deceleration rate is reached.The present application obtains steady deceleration rate target range according to aircraft brake energy, realizes the control to brake pressure according to deceleration rate target range, can improve brake deceleration rate, and reduce braking distance.

Description

Technical Field

[0001] This invention relates to the field of aircraft anti-skid braking technology, specifically to an adaptive braking steady-state deceleration rate adjustment method based on aircraft braking energy. Background Technology

[0002] There are many factors that affect aircraft anti-skid braking control, among which the aircraft braking energy, pavement contact coefficient, brake disc performance, and brake pressure control are key factors that directly affect the efficiency of anti-skid braking.

[0003] When an aircraft has high braking energy, or when the brake disc torque diminishes in a wet environment, this can lead to an excessively low braking deceleration rate, potentially causing the aircraft to overshoot the runway. Conversely, when an aircraft has low braking energy, or when the brake disc braking capacity is too high, the brakes may approach the slip point or enter anti-skid mode, resulting in an unstable braking process.

[0004] An analysis of existing braking control methods reveals that the rated braking pressure control method, when used during braking, suffers from insufficient deceleration and excessively long braking distances under high aircraft energy or when brake disc torque decays. Furthermore, when aircraft energy is low or the pavement contact coefficient is insufficient, anti-skid operation is prone to occur. In summary, the quasi-adjustable rated braking pressure control method currently used in most aircraft has the following drawbacks: 1) Insufficient braking deceleration rate under high-energy operating conditions or wet environments; 2) Frequent slippage is likely to occur when the energy level is low or the track surface bonding coefficient is insufficient; 3) The braking control method is too simple and cannot fully utilize the braking capacity of the main wheel.

[0005] If an aircraft is in a high-energy state during a high-speed landing and there are no other braking measures such as drag chute or speed brakes, the braking distance will be too long, and in severe cases, the aircraft may overrun the runway.

[0006] In existing technology, when an aircraft urgently needs to decelerate, it outputs the maximum braking command, and the corresponding system controls the output of the maximum constant braking pressure. The shortcoming of this technology is that it does not take into account the torque dispersion of the brake disc itself, the wet-state fade of the brake disc, and the problem of large braking energy. When the braking pressure output is the rated braking pressure, the brake output is a constant maximum braking pressure, which may result in insufficient deceleration or frequent anti-skid operation. Summary of the Invention

[0007] To address the shortcomings in the aforementioned background technology, this invention primarily solves the problem of braking deceleration rate under different energy states in the prior art. This invention provides an adaptive braking steady-state deceleration rate adjustment method based on aircraft braking energy. This method obtains the target range of steady-state deceleration rate based on the aircraft braking energy, and controls the braking pressure based on the target range of deceleration rate, which can improve the braking deceleration rate and reduce the braking distance.

[0008] The first objective of this invention is to provide an adaptive braking steady-state deceleration rate adjustment method based on aircraft braking energy, comprising: Obtain the aircraft's ground speed at the moment of initial braking. The braking energy state at the start of braking is obtained from the aircraft ground speed and total weight signals. Collect the current wheel speed and the wheel speed after 1 second; Based on the current wheel speed and the wheel speed 1 second later, obtain the braking deceleration rate within 1 second; Based on the braking energy state at the start of braking and the braking deceleration rate within 1 second, adjust the braking pressure until the steady-state deceleration rate of the wheels is reached.

[0009] Preferably, when collecting the current wheel speed and the wheel speed 1 second later, the aircraft should decelerate to a steady-state speed range of 25km / h to 250km / h, and the system should not be engaged in anti-skid operation, with both left and right braking command strokes greater than 95%.

[0010] Preferably, the current wheel speed is collected using the following method: The wheel speed was sampled every 2ms with a period of 10ms, for a total of 5 consecutive samplings. The sampled wheel speed signals were then filtered to remove the maximum and minimum values, resulting in wheel speed signals arranged in chronological order as V. 01 V 02 V 03 The current wheel speed is calculated using the following formula: V 00 =0.2V 01 +0.3V 02 +0.5V 03 In the formula ， V 00 This represents the current wheel speed.

[0011] Preferably, the wheel speed after 1 second is the wheel speed collected again in the same manner 1 second after the current wheel speed is collected.

[0012] Preferably, the braking deceleration rate within 1 second is the difference between the current wheel speed and the wheel speed 1 second later.

[0013] Preferably, the braking pressure is adjusted based on the braking energy state at the start of braking and the braking deceleration rate within 1 second until the steady-state deceleration rate of the wheels is reached, including: Select the target deceleration rate range based on the braking energy state of the aircraft at the start of braking; Based on whether the braking deceleration rate within 1 second is within or outside the target deceleration rate range, the braking pressure is adjusted until the steady-state deceleration rate of the wheel is reached.

[0014] Preferably, when the braking energy state is low, the target deceleration rate range is 3.5 m / s². 2 ~4.5m / s 2 When the braking energy state is at its highest level, the target deceleration rate range is 2.5 m / s². 2 ~3.5m / s 2 ; The term "low energy state" refers to the braking state when the aircraft's normal landing weight is 12t~16t and the initial braking speed is 250km / h~300km / h. The term "high energy state" refers to the braking state when the aircraft's maximum landing weight is 16t~20t and the braking energy is greater than the maximum energy in the low energy state.

[0015] Preferably, the brake pressure is adjusted by decreasing or increasing it at a rate of 1 MPa / s.

[0016] The second objective of this invention is to provide a computer program product, including a computer program that, when executed by a processor, implements the aforementioned adaptive braking steady-state deceleration rate adjustment method based on aircraft braking energy.

[0017] A third objective of this invention is to provide an electronic device comprising: Processor; and Memory for storing the executable instructions of the processor; The processor is configured to execute the aforementioned adaptive braking steady-state deceleration rate adjustment method based on aircraft braking energy by executing the executable instructions.

[0018] The present invention has at least the following beneficial effects: This invention provides an adaptive braking steady-state deceleration rate adjustment method based on aircraft braking energy. This method determines the target range of the steady-state deceleration rate based on the aircraft's braking energy, and then controls the braking pressure according to this target range. Compared to existing braking control methods, this adaptive braking steady-state deceleration rate adjustment method based on aircraft braking energy can fully utilize the braking capacity of the main landing gear, significantly improve the braking deceleration rate under maximum landing conditions or wet environments, shorten the braking distance, and effectively reduce the number of braking skids during normal landing, thus improving the stability of the system control. Attached Figure Description

[0019] Figure 1 The flowchart illustrates an adaptive braking steady-state deceleration rate adjustment method based on aircraft braking energy, as provided by this invention. Detailed Implementation

[0020] In order to illustrate the technical means and effects adopted by the present invention to achieve the intended purpose, the following detailed description is provided in conjunction with the embodiments.

[0021] The purpose of this invention is to address the problem of braking deceleration rate under different energy states in the prior art. This invention proposes an adaptive braking steady-state deceleration rate adjustment method based on aircraft braking energy.

[0022] To achieve the above objectives, see Figure 1 As shown, an adaptive braking steady-state deceleration rate adjustment method based on aircraft braking energy includes: S1. Obtain the aircraft ground speed at the moment of initial braking. The braking energy state at the start of braking is obtained from the aircraft ground speed and total weight signals. Aircraft energy distribution is specified in the system design requirements and can be calculated using aircraft ground speed and total weight signals. Generally, normal landing is a low-energy state, while maximum landing and aborted takeoff are high-energy states.

[0023] Most tricycles have a landing weight of about 12 to 20 tons and an initial braking speed of about 250 km / h to 300 km / h.

[0024] The weight of an aircraft during normal landing is 12t to 16t. Therefore, when the weight is 16t and the initial braking speed is 300km / h, the braking state is a low-energy state, and the braking energy is the maximum energy in the low-energy state.

[0025] The maximum landing weight of an aircraft is 16t to 20t. When the braking energy is greater than the maximum energy in the low energy state, the braking state is the high energy state.

[0026] S2. Collect the current wheel speed and the wheel speed after 1 second; Based on the current wheel speed and the wheel speed 1 second later, obtain the braking deceleration rate within 1 second; When collecting the current wheel speed and the wheel speed 1 second later, the aircraft should decelerate to a steady-state speed range of 25km / h to 250km / h, and the system should not be engaged in anti-skid operation, with both left and right braking command travel greater than 95%.

[0027] The current wheel speed is collected using the following method: The wheel speed was sampled every 2ms with a period of 10ms, for a total of 5 consecutive samplings. The sampled wheel speed signals were then filtered to remove the maximum and minimum values, resulting in wheel speed signals arranged in chronological order as V. 01 V 02 V 03 The current wheel speed is calculated using the following formula: V 00 =0.2V 01 +0.3V 02 +0.5V 03 In the formula ， V 00 This represents the current wheel speed.

[0028] The wheel speed 1 second later is the wheel speed collected again in the same way 1 second after the current wheel speed is collected.

[0029] The braking deceleration rate within 1 second is the difference between the current wheel speed and the wheel speed after 1 second.

[0030] S3. Adjust the braking pressure according to the braking energy state at the start of braking and the braking deceleration rate within 1 second until the steady-state deceleration rate of the wheels is reached.

[0031] Based on the braking energy state at the start of braking and the braking deceleration rate within 1 second, adjust the braking pressure until the steady-state deceleration rate of the wheels is reached, including: Select the target deceleration rate range based on the braking energy state of the aircraft at the start of braking; Based on whether the braking deceleration rate within 1 second is within or outside the target deceleration rate range, the braking pressure is adjusted until the steady-state deceleration rate of the wheel is reached.

[0032] Based on the aircraft's total weight and ground speed signals, the aircraft's landing braking energy state can be identified. The aircraft's landing weight falls within a certain range, encompassing normal landing and maximum landing weights. When the braking energy state is low, the target deceleration rate range is 3.5 m / s². 2 ~4.5m / s 2When the braking energy state is at its highest level, the target deceleration rate range is 2.5 m / s². 2 ~3.5m / s 2 ; The term "low energy state" refers to the braking state when the aircraft's normal landing weight is 12t~16t and the initial braking speed is 250km / h~300km / h. The term "high energy state" refers to the braking state when the aircraft's maximum landing weight is 16t~20t and the braking energy is greater than the maximum energy in the low energy state.

[0033] When adjusting the brake pressure, decrease or increase the brake pressure at a rate of 1 MPa / s.

[0034] It should be noted that during the landing braking process, at the initial touchdown, the aircraft has vertical lift and the wheel load is relatively small, making it impossible to accurately assess the deceleration rate target. Therefore, no steady-state deceleration rate adjustment is performed during high-speed landing. After the anti-skid fails, the aircraft urgently needs to stop or roll, so there is no need to perform steady-state deceleration rate adjustment.

[0035] The adaptive braking steady-state deceleration rate adjustment is performed when the aircraft ground speed is between 25 km / h and 250 km / h.

[0036] To illustrate the adaptive braking steady-state deceleration rate adjustment method based on aircraft braking energy provided by the present invention, the specific methods include the following.

[0037] Step 1: Aircraft Status Identification: If the aircraft is in a ground-to-air state with no communication failure, the braking energy status Q of the aircraft is determined based on the aircraft's total weight signal M and the aircraft's ground speed V at the start of braking. This energy value is calculated once and locked when the aircraft touches down, until the anti-skid fails. The calculation formula is shown in (1).

[0038] Q=0.5MV 2 (1) This step utilizes aircraft status information to calculate the aircraft's braking energy.

[0039] Step Two: Steady-State Deceleration Rate Calculation: When the aircraft ground speed is between 25 km / h and 250 km / h, with no anti-skid operation and both left and right brake command travel greater than 95%, calculate the steady-state deceleration rate. The brake control software has a cycle of T = 10 ms, and wheel speeds are collected every 2 ms. Therefore, five wheel speeds are collected within one software cycle: V1, V2, V3, V4, and V5. The wheel speed signals V1 to V5 are filtered to remove the maximum and minimum values, resulting in three wheel speed signals arranged in chronological order as V1, V2, V3, V4, and V5. 01 V 02 V 03The following formula (2) is used to calculate the wheel speed result V0 of the current software running cycle.

[0040] V 00 =0.2V 01 +0.3V 02 +0.5V 03 (2) The software operation cycle data collection wheel speed filtering result V0 is obtained after 1 second. Therefore, the calculation of the braking deceleration rate a within this 1 second is shown in formula (3): a=V 00 -V0; (3) This step uses a filtering calculation method to obtain the wheel speed and calculates the current deceleration rate.

[0041] Step 3: Steady-state deceleration rate adjustment: Adjust the braking deceleration rate according to the steady-state deceleration rate of the wheel.

[0042] Based on the aircraft state identification results, if the aircraft is in a low-energy state, the typical target deceleration rate is within the range of 3.5 m / s². 2 ~4.5m / s 2 Between; if the aircraft's energy is in a high-energy state, the typical target deceleration rate range is 2.5 m / s². 2 ~3.5m / s 2 Therefore, the braking system adjusts the steady-state deceleration rate as follows: Based on the system design requirements for classifying braking energy states, when Q is in a low energy state: If a is less than 3.5 m / s 2 Then increase the braking pressure at a rate of 1 MPa / s until the steady-state deceleration rate reaches 3.5 m / s². 2 ~4.5m / s 2 Between; if a is greater than 4.5 m / s 2 Then, reduce the braking pressure at a rate of 1 MPa / s until the steady-state deceleration rate reaches 3.5 m / s. 2 ~4.5m / s 2 between.

[0043] Based on the system design requirements for classifying braking energy states, when Q is in a high-energy state: If a is less than 2.5 m / s 2 Then increase the braking pressure at a rate of 1 MPa / s until the steady-state deceleration rate reaches 2.5 m / s². 2 ~3.5m / s 2 Between; if a is greater than 3.5 m / s 2 Then, reduce the braking pressure at a rate of 1 MPa / s until the steady-state deceleration rate reaches 2.5 m / s². 2 ~3.5m / s2 between.

[0044] This step determines the target range of steady-state deceleration rate based on the aircraft's braking energy, and then controls the braking pressure based on the target range of deceleration rate.

[0045] The adaptive steady-state deceleration rate control method based on aircraft energy proposed in this invention is compared with conventional control methods, as shown in Table 1.

[0046] Table 1 Comparison of the present invention and conventional methods

[0047] To further illustrate the method provided by this invention, specific examples are given.

[0048] Step 1: Aircraft Status Identification The braking system can receive the aircraft's total weight signal M and the aircraft's ground speed V at the start of braking through communication with the host computer. The aircraft's total weight M ranges from 12t to 20t, and the aircraft's ground speed V ranges from -150m / s to 150m / s.

[0049] Under normal circumstances, the maximum landing speed of this aircraft is 80 m / s, the normal landing weight range is 12t to 16t, and the maximum landing weight range is 16t to 20t. When the total weight of the aircraft M is greater than 16t and the landing speed is 80m / s, the corresponding braking energy is greater than 51.2MJ, which is considered to be a high-energy braking condition.

[0050] At this moment, the braking system receives the aircraft's ground-to-air status as ground-based, and receives the aircraft's total weight M = 13.3t and ground speed V = 78m / s. Therefore, the braking energy at this moment is calculated as follows: Q=0.5×13.3×1000×78×78=40.5MJ (1) Step 2: Calculation of Steady-State Deceleration Rate At the start of braking, the aircraft ground speed V = 78 m / s. Since the aircraft ground speed V is greater than 250 km / h, it is not in the steady-state region. During the deceleration to steady-state speed range of 25 km / h to 250 km / h, corresponding to 6.97 m / s to 69.4 m / s, the system does not perform anti-skid operation, and the left and right braking command travel is 100%. The steady-state deceleration is then calculated.

[0051] The system sequentially collected five wheel speeds within the current software cycle: V1=69.0m / s, V2=68.6m / s, V3=68.9m / s, V4=68.1m / s, and V5=68.5m / s. The wheel speed signals V1 to V5 were sorted, and the maximum and minimum values ​​were removed, resulting in three wheel speed signals arranged in chronological order: V 01 =68.6m / s, V02 =68.9m / s, V 03 =68.5 m / s. Final current cycle wheel speed signal acquisition value V 00 The calculation is as follows: V 00 =0.2V 01 +0.3V 02 +0.5V 03 =0.2×68.6+0.3×68.9+0.5×68.5=68.64m / s (2) A value is collected every 10ms. The wheel speed signal is collected as V0=65.25m / s in the period after 1s.

[0052] Therefore, the deceleration rate 'a' for the current cycle is obtained, and the calculation process is as follows: a=V 00 -V0 = 68.64 - 65.25 = 3.39 m / s 2 (3) Step 3: Steady-state deceleration rate adjustment Step one identified the aircraft's braking energy as 40.5 MJ, which is less than 51.2 MJ. Therefore, the aircraft's braking condition is identified as a low-energy state, and the target deceleration rate should be within the range of 3.5 m / s². 2 ~4.5m / s 2 between.

[0053] Step two yielded a steady-state deceleration rate of 3.39 m / s. 2 The value is less than the minimum target range value of 3.5 m / s. 2 Therefore, the braking pressure is increased at a rate of 1 MPa / s.

[0054] Before steady-state deceleration rate control, the system output braking pressure is 10 MPa, and the braking deceleration rate is 3.39 m / s². 2 After steady-state deceleration rate adjustment, when the braking pressure is increased at a rate of 1 MPa / s to 11.5 MPa, the braking deceleration rate is 3.5 m / s². 2 Subsequently, if the braking deceleration rate remains greater than 3.5 m / s 2 The system will maintain output pressure until the anti-slip failure speed drops below the specified speed.

[0055] The main experimental data comparison is shown in Table 2. Based on the data in the table and theoretical analysis, it can be concluded that the rated control method has a low braking deceleration rate, especially under high-energy conditions, resulting in an excessively long braking distance. Adopting an adaptive steady-state deceleration rate control method, especially under high-energy conditions, can fully utilize the braking capacity of the main engine wheels, improve the braking deceleration rate, and reduce the braking distance.

[0056] Table 2 Main Experimental Data

[0057] In this embodiment, steady-state deceleration rate control is achieved during the braking process based on the aircraft's braking energy state. Experimental and theoretical analyses show that the adaptive braking steady-state deceleration rate adjustment method based on aircraft braking energy can improve the braking deceleration rate and reduce the braking distance.

[0058] The present invention provides a computer program product, including a computer program that, when executed by a processor, implements the above-described adaptive braking steady-state deceleration rate adjustment method based on aircraft braking energy.

[0059] This invention provides an electronic device, comprising: Processor; and Memory for storing the executable instructions of the processor; The processor is configured to execute the aforementioned adaptive braking steady-state deceleration rate adjustment method based on aircraft braking energy by executing the executable instructions.

[0060] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An adaptive braking steady-state deceleration rate adjustment method based on aircraft braking energy, characterized in that, include: Obtain the aircraft's ground speed at the moment of initial braking. The braking energy state at the start of braking is obtained from the aircraft ground speed and total weight signals. Collect the current wheel speed and the wheel speed after 1 second; Based on the current wheel speed and the wheel speed 1 second later, obtain the braking deceleration rate within 1 second; Based on the braking energy state at the start of braking and the braking deceleration rate within 1 second, adjust the braking pressure until the steady-state deceleration rate of the wheels is reached. When collecting the current wheel speed and the wheel speed 1 second later, the aircraft should decelerate to a steady-state speed range of 25 km / h to 250 km / h, and the system should not be engaged in anti-skid operation, with both left and right braking command travel greater than 95%. The current wheel speed is collected using the following method: The wheel speed was sampled every 2ms with a period of 10ms, for a total of 5 consecutive samplings. The sampled wheel speed signals were then filtered to remove the maximum and minimum values, resulting in wheel speed signals arranged in chronological order as V. 01 V 02 V 03 The current wheel speed is calculated using the following formula: V 00 =0.2V 01 +0.3V 02 +0.5V 03 In the formula, V 00 This represents the current wheel speed. Based on the braking energy state at the start of braking and the braking deceleration rate within 1 second, adjust the braking pressure until the steady-state deceleration rate of the wheels is reached, including: Select the target deceleration rate range based on the braking energy state of the aircraft at the start of braking; Depending on whether the braking deceleration rate within 1 second is within or outside the target deceleration rate range, the braking pressure is adjusted until the steady-state deceleration rate of the wheel is reached. When the braking energy state is low, the target deceleration rate range is 3.5 m / s². 2 ~4.5m / s 2 When the braking energy state is at its highest level, the target deceleration rate range is 2.5 m / s². 2 ~3.5m / s 2 ; The term "low energy state" refers to the braking state when the aircraft's normal landing weight is 12t~16t and the initial braking speed is 250km / h~300km / h. The term "high energy state" refers to the braking state when the aircraft's maximum landing weight is 16t~20t and the braking energy is greater than the maximum energy in the low energy state. When adjusting the brake pressure, decrease or increase the brake pressure at a rate of 1 MPa / s.

2. The adaptive braking steady-state deceleration rate adjustment method based on aircraft braking energy according to claim 1, characterized in that, The wheel speed 1 second later is the wheel speed collected again in the same way 1 second after the current wheel speed is collected.

3. The adaptive braking steady-state deceleration rate adjustment method based on aircraft braking energy according to claim 1, characterized in that, The braking deceleration rate within 1 second is obtained based on the difference between the current wheel speed and the wheel speed after 1 second.

4. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by the processor, it implements the adaptive braking steady-state deceleration rate adjustment method based on aircraft braking energy as described in any one of claims 1 to 3.

5. An electronic device, characterized in that, include: processor; as well as Memory for storing the executable instructions of the processor; The processor is configured to execute the adaptive braking steady-state deceleration rate adjustment method based on aircraft braking energy as described in any one of claims 1 to 3 by executing the executable instructions.

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