CN110615109A - Fault-tolerant control method for electromechanical compound transmission system of aircraft - Google Patents

Abstract

The invention discloses a fault-tolerant control method for an aircraft electromechanical compound transmission system, which includes judging whether the main body of the fault is the engine, the first motor or the second motor; if the engine fails, adjusting the torque of the first motor and the torque of the second motor to control The planetary coupling mechanism runs; if the second motor fails, adjust the torque of the first motor to control the operation of the planetary coupling mechanism; if the first motor fails, then judge whether the third failure factor is 1; if not, adjust the second motor If so, adjust the torque of the second motor to control the operation of the planetary coupling mechanism, and brake the K2 row sun gear to increase the collective pitch of the rotor. The invention can control the redistribution of torque, compensate for the function or performance loss of faulty actuators, thereby ensuring the safety performance of the aircraft.

Description

A fault-tolerant control method for an aircraft electromechanical compound transmission system

technical field

The invention relates to the technical field of aircraft flight control, in particular to a fault-tolerant control method for an aircraft electromechanical compound transmission system.

Background technique

At this stage, increasing the operating speed of aircraft is one of the important directions of aircraft development. At present, there are generally three ways to change the rotational speed of the rotor. One is to change the rotational speed of the aircraft engine according to the aircraft control system, and the rotational speed of the rotor changes when the rotational speed of the engine changes. The second is to change the rotational speed of the power turbine. The usual method is to adjust some geometric parameters of the engine, such as the angle of attack of the power turbine, so that the rotor speed can be changed without changing the working state of the engine. The third is to change the transmission ratio of the transmission system to change the output speed.

For the first solution, both Airbus Helicopters EC135 and EC145 have adopted it. The disadvantage of this solution is that the engine has a relatively fixed operating speed. It cannot work at a position where its working efficiency is relatively high. In order to avoid this problem, the variation range of the rotor speed will be relatively small, for example, the EC135 mentioned above is only 3%. Different from the first solution, the second solution can ensure the working efficiency of the engine, but it needs to install various control mechanisms inside the engine, which is relatively difficult technically and will increase the mass of the engine. As for the third scheme, compared with the other two schemes, the cost performance of this scheme is the highest.

In order to keep the engine speed basically constant and use the transmission system to change the speed, it is better to use the electromechanical compound transmission. When it is diagnosed and treated, the aircraft will not be able to achieve its expected effect and even be in danger due to loss of control, resulting in irreparable losses. Moreover, the electromechanical compound transmission itself is a relatively complicated system, which contains many components. The failure of each component will bring problems to the operation of the transmission system, and even some failures will make the transmission system dangerous during operation, but In the prior art, there is no control method aimed at ensuring the safety and high efficiency of the electromechanical compound transmission system.

Contents of the invention

The purpose of the present invention is to provide a fault-tolerant control method for an aircraft electromechanical compound transmission system, which can realize control redistribution and compensate for the loss of the function or performance of a faulty actuator, thereby ensuring the safety performance of the aircraft.

To achieve the above object, the present invention provides the following technical solutions:

A fault-tolerant control method for an aircraft electromechanical compound transmission system, applied to an aircraft electromechanical compound transmission system, the system includes a controller, an engine, a first motor, a second motor, a planetary coupling mechanism, a brake and a rotor, and the planetary coupling mechanism includes K2 row of sun gears, the method includes:

Determine whether the fault subject is the engine, the first motor or the second motor;

If the engine fails, the first failure factor is obtained, and the first failure factor represents the degree of the engine failure;

calculating the torque of the first motor and the torque of the second motor according to the first failure factor;

adjusting the current torque of the first motor to the torque of the first motor, and adjusting the current torque of the second motor to the torque of the second motor;

If the second motor fails, the second failure factor and the torque of the engine are obtained, and the second failure factor represents the degree of failure of the second motor;

calculating the torque of the first motor according to the second failure factor and the torque of the engine;

adjusting the current torque of the first motor to the torque of the first motor;

If the first motor fails, the third failure factor and the torque of the engine are obtained, and the third failure factor represents the degree of failure of the first motor;

judging whether the third failure factor is 1;

If not, then calculate the torque of the second motor according to the third failure factor and the torque of the engine;

adjusting the current torque of the second motor to the torque of the second motor;

If so, calculate the torque of the second motor according to the torque of the engine;

The torque of the current second motor is adjusted to the torque of the second motor, and the K2 sun gear is braked to increase the collective pitch of the rotor.

Optionally, the calculating the torque of the first motor and the torque of the second motor according to the first failure factor includes:

Calculate the required power according to the principle of power conservation;

calculating the torque of the second motor according to the required power and the first failure factor;

The torque of the first electric machine is calculated according to the first failure factor and the torque of the second electric machine.

Optionally, the calculating the torque of the first motor according to the second failure factor and the torque of the engine includes:

use the formula Calculate the torque of the first motor, where (1-δ ₃ )T _b n _{b =} P _need -T _a na -T _{e ne} , is the angular acceleration of the engine, _ne is the engine speed, T _e is the torque of the engine, T _a is the torque of the first motor, T _b is the torque of the second motor, T _f is the load torque, n _a is The speed of the first motor, n _b is the speed of the second motor, and _δ3 is the second failure factor.

Optionally, the calculating the torque of the second motor according to the torque of the engine includes:

The torque of the second motor is calculated using the formula T _b =g(T _o ,T _e ), wherein T _b is the torque of the second motor, T _o is the output power, T _e is the engine torque, g(T _o ,T _e ) is a function of output power and engine torque.

Optionally, the calculation of required power according to the principle of power conservation includes:

The required power is calculated using the formula P _e +P _a +P _b =P _need , wherein P _e provides power for the engine, P _a provides power for the first motor, P _b provides power for the second motor, and P _need is the required power.

Optionally, the calculating the torque of the second motor according to the required power and the first failure factor includes:

use the formula Calculate the torque of the second motor, where T _b is the torque of the second motor, P _need is the required power, T _a is the torque of the first motor, n _a is the speed of the first motor, and δ ₁ is the first Failure factor, T _e is the torque of the engine, _ne is the speed of the generator, and n _b is the speed of the second electric machine.

Optionally, the calculating the torque of the first motor according to the first failure factor and the torque of the second motor includes:

use the formula Calculate the torque of the first motor, where, is the angular acceleration of the engine, _ne is the rotational speed of the generator, δ ₁ is the first failure factor, T _e is the torque of the engine, T _a is the torque of the first motor, T _b is the torque of the second motor, T _f is the load torque.

According to the specific embodiments provided by the invention, the invention discloses the following technical effects:

On the one hand, because the present invention does not need to redesign the control rate, and does not need to solve the optimization algorithm, the calculation speed of the computer is increased, and the online running speed is improved; Conservation and engine constant speed, through the active cooperative torque compensation of the faulty engine, the first motor and the second motor, control redistribution is realized, and the function or performance loss caused by the faulty actuator to the electromechanical compound transmission system is compensated to ensure the safety of the aircraft. safety performance.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the accompanying drawings required in the embodiments. Obviously, the accompanying drawings in the following description are only some of the present invention. Embodiments, for those of ordinary skill in the art, other drawings can also be obtained based on these drawings without any creative effort.

Fig. 1 is the structural representation of aircraft electromechanical compound transmission system of the present invention;

Fig. 2 is the method flowchart of the fault-tolerant control method of the aircraft electromechanical compound transmission system of the present invention;

In the figure: 1-engine, 2-first motor, 3-second motor, 4-third motor.

Detailed ways

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

The purpose of the present invention is to provide a fault-tolerant control method for an aircraft electromechanical compound transmission system, which can realize control redistribution and compensate for the loss of the function or performance of a faulty actuator, thereby ensuring the safety performance of the aircraft.

In order to make the above objects, features and advantages of the present invention more comprehensible, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

Fault-tolerant control means that when one or several components in the system have problems, the fault-tolerant control system can still operate in the target mode or slightly lower than the target, but still ensure that the system does not appear dangerous.

Fig. 1 is the structure schematic diagram of aircraft electromechanical compound transmission system of the present invention, as shown in Fig. 1, electromechanical compound transmission system among the present invention comprises three actuators, is engine 1, first motor 2 and second motor 3 respectively , and these three actuators exist independently, wherein the engine 1, the first motor 2 and the second motor 3 can be used as their redundant actuators (the figure also includes a third motor 4, which is used to give other parts of the mechanism powered by). Therefore, if the second motor 3 fails, it can be reconfigured through the control allocation algorithm, and the remaining non-faulty actuators (engine 1 and first motor 2) can be used to compensate for the loss of the second motor 3, so that the desired effect can be achieved or Slightly below expectations. Similarly, if the engine 1 breaks down, it can also be compensated by non-faulty actuators (the first motor 2 and the second motor 2 ).

According to the degree of failure of the actuator, its failure factor δ _i (0≤δ _i ≤1, i=1, 2, 3) is obtained, where 0 means no failure, 1 means complete failure, and the failure factor is based on some According to the method of fault diagnosis, if the torque that should be input by the actuator is a, but the actual input is b due to the fault, then the failure factor is (ab)/a. Here, a failure factor is assumed, for example, if the second motor appears failure, then the matrix of failure factors at this time is as follows:

fault＝[0 0 δ ₃ ] (1)

The failure matrix is used as the control input of the control distribution system. After the actuator of the electromechanical compound transmission system fails, the use of the control distribution module will redistribute the torque input of the actuator according to the failure factor, using the fault-free redundancy The actuator compensates for the faulty actuator so that the redistribution results meet the requirements of the transmission system.

The specific control method is shown in Figure 2. A fault-tolerant control method for an aircraft electromechanical compound transmission system is applied to the aircraft electromechanical compound transmission system in Figure 1. The method includes:

Step 201: Determine whether the fault subject is the engine, the first motor or the second motor;

Step 202: If the engine fails, obtain a first failure factor, the first failure factor represents the degree of engine failure;

Step 203: Calculate the torque of the first motor and the torque of the second motor according to the first failure factor;

Step 204: adjusting the current torque of the first motor to the torque of the first motor, and adjusting the current torque of the second motor to the torque of the second motor;

Step 205: If the second motor fails, obtain a second failure factor and the torque of the engine, the second failure factor represents the degree of failure of the second motor;

Step 206: Calculate the torque of the first motor according to the second failure factor and the torque of the engine;

Step 207: adjusting the current torque of the first motor to the torque of the first motor;

Step 208: If the first motor is faulty, obtain a third failure factor and the torque of the engine, the third failure factor represents the degree of failure of the first motor;

Step 209: judging whether the third failure factor is 1;

Step 210: If not, calculate the torque of the second motor according to the third failure factor and the torque of the engine;

Step 211: adjusting the current torque of the second motor to the torque of the second motor;

Step 212: If yes, calculate the torque of the second motor according to the torque of the engine;

Step 213: Adjust the current torque of the second motor to the torque of the second motor, and brake the K2 row sun gear to increase the collective pitch of the rotor.

Specifically, the control allocation module redistributes the torque that each actuator should provide according to the failure factor and the virtual control quantity obtained by the controller (the torque of each actuator calculated by the controller according to the fault-free), and then the actuators are distributed according to the torque of the actuator. Torque is provided to the planetary coupling so that the planetary coupling operates in the desired manner.

In the electromechanical compound transmission system of the present invention, each actuator failure must be considered, and the control distribution module is used to redistribute the torque that each actuator needs to provide. The principle of the control distribution module is based on power conservation and engine speed Constantly obtained. For the engine, the first motor and the second motor, the control distribution module will redistribute the torque provided by the actuator according to the failure factor. The fault calculation method for each actuator is different. The following will give the Control allocation scheme for actuator failure (which actuator failure is diagnosed by the diagnostic program in the controller).

1. Engine failure

The engine is used as the power supply device of the electromechanical compound transmission system. If the engine fails, the electromechanical compound transmission system cannot operate as expected. Here, it is assumed that the engine fails at the 10th second, and its first failure factor is δ ₁ . The module redistributes the torque provided by the first electric machine and the second electric machine based on the failure factor.

The reallocation method is based on power balance, namely:

P _e +P _a +P _b ＝P _need (2)

Where P _e provides power for the engine, P _a provides power for the first motor, P _b provides power for the second motor, and P _need is the required power.

When the engine fails, the torque of the first motor is calculated according to the dynamic model of the planetary coupling mechanism, that is, to keep the engine speed constant:

In the formula, is the angular acceleration of the engine, δ ₁ is the first failure factor, _ne is the engine speed, T _e is the torque provided by the engine, T _a is the torque provided by the first motor, T _b is the torque provided by the second motor, T _f is the load torque, and the torque of the second motor is calculated by the following formula:

Among them, T _b is the torque provided by the second motor, P _need is the required power, T _a is the torque provided by the first motor, n _a is the speed of the first motor, δ ₁ is the first failure factor, n _e is the engine speed, T _e is the torque provided by the engine, n _b is the second motor speed;

Substituting Equation (4) into Equation (3) can obtain the torque that the first motor needs to provide, and it is also necessary to ensure that the torques of the engine, the first motor, and the second motor are within their torque ranges.

2. The second motor failure

When the second motor fails, the failure factor of the control distribution module redistributes each control variable, and the redistribution principle is still power conservation.

The torque of the first motor is calculated according to the dynamic model of the planetary coupling mechanism, i.e. keeping the speed of the engine constant:

In the formula, (1-δ ₃ )T _b n _{b ＝} P _need -T _a na -T _e ne _e , is the angular acceleration of the engine, _ne is the engine speed, T _e is the torque provided by the engine, T _a is the torque provided by the first motor, T _b is the torque provided by the second motor, T _f is the load torque, and n _a is The first motor speed, n _b is the second motor speed, P _need is the required power, and δ ₃ is the second failure factor;

The torque to be provided by the first motor can be obtained according to the above formula, and the torque to be provided by the engine is given by the controller, and the torques of the engine, the first motor and the second motor are guaranteed to be within their torque ranges.

3. The first motor failure

When the first motor fails with the third failure factor δ2, where _δ2 is not ₁ , that is, the first motor is incompletely faulty, the control allocation method is similar to the second motor fault.

When the first motor fails completely, that is, when the third failure factor δ ₂ is equal to 1, because of the special position and function of the first motor, the whole system cannot work when the first motor fails completely, so if the first motor fails completely, the transmission The system cannot output power, so in order to make the system work normally, the brake is used to brake the K2 sun gear of the planetary coupling mechanism.

At this time, the control allocation module needs to redistribute the torque that the second motor needs to provide, and the torque of the second motor is as follows:

T _b ＝g(T _o , T _e ) (6)

In the formula, T _o is the output power, T _e is the engine torque, and g(T _o , T _e ) is a function of the output torque and the engine torque.

The torque of the second motor should be between its minimum and maximum torque, that is:

T b _min ≤ T _b ≤ T b _max (7)

Since the brake is added to the shaft of the K2 sun gear, the output speed of the transmission mechanism will drop. In order to make the rotor generate torque running according to the normal torque, the collective pitch of the rotor should be appropriately increased at this time, so that the system can operate according to the normal torque. Runs as expected, or slightly below expectations.

In general, using the distribution module can quickly take effective measures against the fault, and immediately adjust the output torque of the non-faulty actuator under the joint action of its own controller and distribution module, and promptly and effectively compensate for the fault caused by the faulty actuator. Insufficient output power of the system.

The present invention also discloses the following technical effects:

On the one hand, because the present invention does not need to redesign the control rate, and does not need to solve the optimization algorithm, the calculation speed of the computer is increased, and the online running speed is improved; Conservation and engine constant speed, through the active cooperative torque compensation of the faulty engine, the first motor and the second motor, control redistribution is realized, and the function or performance loss caused by the faulty actuator to the electromechanical compound transmission system is compensated to ensure the safety of the aircraft. safety performance.

Each embodiment in this specification is described in a progressive manner, each embodiment focuses on the difference from other embodiments, and the same and similar parts of each embodiment can be referred to each other.

In this paper, specific examples have been used to illustrate the principle and implementation of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea; meanwhile, for those of ordinary skill in the art, according to the present invention Thoughts, there will be changes in specific implementation methods and application ranges. In summary, the contents of this specification should not be construed as limiting the present invention.

Claims (7)

1. An aircraft electromechanical compound transmission system fault-tolerant control method is applied to an aircraft electromechanical compound transmission system, the system comprises a controller, an engine, a first motor, a second motor, a planetary coupling mechanism, a brake and a rotor wing, the planetary coupling mechanism comprises K2 rows of sun gears, and the method is characterized by comprising the following steps:

judging whether the fault main body is an engine, a first motor or a second motor;

if the engine fails, acquiring a first failure factor, wherein the first failure factor represents the degree of the engine failure;

calculating the torque of the first motor and the torque of the second motor according to the first failure factor;

adjusting the current first motor torque to the torque of the first motor, and adjusting the current second motor torque to the torque of the second motor;

if the second motor fails, acquiring a second failure factor and the torque of the engine, wherein the second failure factor represents the degree of the second motor failure;

calculating the torque of the first motor according to the second failure factor and the torque of the engine;

adjusting a current first motor torque to a torque of the first motor;

if the first motor fails, acquiring a third failure factor and the torque of the engine, wherein the third failure factor represents the degree of the failure of the first motor;

judging whether the third failure factor is 1;

if not, calculating the torque of the second motor according to the third failure factor and the torque of the engine;

adjusting a current second motor torque to a torque of the second motor;

if yes, calculating the torque of a second motor according to the torque of the engine;

and adjusting the current torque of the second motor to the torque of the second motor, braking the K2 row sun wheel and increasing the total distance of the rotor wing.

2. The aircraft electro-mechanical compound transmission fault tolerance control method of claim 1, wherein calculating the torque of the first electric machine and the torque of the second electric machine based on the first failure factor comprises:

calculating the required power according to the power conservation principle;

calculating the torque of the second motor according to the required power and the first failure factor;

calculating the torque of the first motor according to the first failure factor and the torque of the second motor.

3. The method of fault-tolerant control of an aircraft electro-mechanical compound transmission system according to claim 1, wherein calculating the torque of the first electric machine based on the second failure factor and the torque of the engine comprises:

using a formulaCalculating a torque of the first electrical machine, wherein (1- δ)₃)T_bn_b＝P_need-T_an_a-T_en_e，Is the angular acceleration of the engine, n_eIs the engine speed, T_eIs the torque of the engine, T_aIs the torque of the first electric machine, T_bIs the torque of the second electric machine, T_fFor load torque, n_aIs the rotational speed of the first motor, n_bIs the rotational speed of the second motor, delta₃Is the second failure factor.

4. The method of fault-tolerant control of an aircraft electromechanical compound transmission system according to claim 1, wherein said calculating a torque of a second electric machine from a torque of the engine comprises:

using the formula T_b＝g(T_o,T_e) Calculating the torque of the second electric machine, wherein T_bIs the torque of the second electric machine, T_oTo output power, T_eIs the engine torque, g (T)_o,T_e) With respect to output power and engine torqueA function.

5. The method for fault-tolerant control of an electromechanical compound transmission system of an aircraft according to claim 2, wherein the calculating of the required power according to the principle of conservation of power comprises:

using the formula P_e+P_a+P_b＝P_needCalculating the required power, wherein P_eFor powering the engine, P_aProviding power to the first motor, P_bFor supplying power to the second motor, P_needIs the required power.

6. The method of fault-tolerant control of an aircraft electro-mechanical compound transmission system according to claim 2, wherein said calculating a torque of a second electrical machine from said demanded power and a first failure factor comprises:

using a formulaCalculating the torque of the second electric machine, wherein T_bIs the torque of the second motor, P_needTo demand power, T_aIs the torque of the first electric machine, n_aIs the rotational speed, delta, of the first electrical machine₁Is a first failure factor, T_eIs the torque of the engine, n_eIs the rotational speed of the generator, n_bIs the rotational speed of the second motor.

7. The aircraft electro-mechanical compound transmission fault tolerance control method of claim 2, wherein calculating the torque of the first electric machine based on the first failure factor and the torque of the second electric machine comprises:

using a formulaCalculating a torque of the first electric machine, wherein,for the angle of the engineSpeed, delta₁Is a first failure factor, T_eIs the torque of the engine, T_aIs the torque of the first electric machine, T_bIs the torque of the second electric machine, T_fIs the load torque.