阅读说明：本技术 一种全压失效时马赫数的获取方法和系统 (Method and system for acquiring Mach number during full-voltage failure ) 是由 杜超超 李少雄 孙海玲 于 2020-12-29 设计创作，主要内容包括：本发明提供一种全压失效时马赫数的获取方法和系统,该方法包括：获取总温传感器当前时刻采集到的总温,根据所述总温和上一时刻存储的马赫数,获取静温；根据所述静温,获取所述静温下的音速；获取惯导系统解算得到的当前时刻的地速,根据所述地速和所述音速获取当前时刻的马赫数。本发明实现算法简单可靠,改动工作量低。(The invention provides a method and a system for acquiring Mach number during full-voltage failure, wherein the method comprises the following steps: acquiring the total temperature acquired by a total temperature sensor at the current moment, and acquiring the static temperature according to the total temperature and the Mach number stored at the previous moment; acquiring the sound velocity at the static temperature according to the static temperature; and acquiring the ground speed of the current moment obtained by resolving by the inertial navigation system, and acquiring the Mach number of the current moment according to the ground speed and the sound speed. The invention has simple and reliable algorithm and low modification workload.)

1. A method for acquiring Mach number during full-pressure failure is characterized by comprising the following steps:

acquiring the total temperature acquired by a total temperature sensor at the current moment, and acquiring the static temperature according to the total temperature and the Mach number stored at the previous moment;

acquiring the sound velocity at the static temperature according to the static temperature;

and acquiring the ground speed of the current moment obtained by resolving by the inertial navigation system, and acquiring the Mach number of the current moment according to the ground speed and the sound speed.

2. The method of claim 1, wherein said obtaining a static temperature comprises:

according to the total temperature T_tAnd Mach number M stored at the last moment, and calculating the static temperature T by adopting the following formula_S；

Wherein k is the adiabatic index of air; and N is the total temperature recovery rate of the total temperature sensor.

3. The method of claim 2, wherein said obtaining the speed of sound at the quiet temperature comprises:

according to the static temperature T_SObtaining the static temperature T by adopting the following formula_SDownward speed of sound c;

wherein R is the gas constant of air.

4. The method according to claim 3, wherein the obtaining the Mach number of the current time according to the ground speed and the sound speed comprises:

will the ground speed V_GroundThe Mach number is taken as the ratio to the speed of sound c.

5. A mach number acquisition system in full-pressure failure, comprising: a total temperature sensor, an inertial navigation system and an air data computer; wherein the atmospheric data computer is to:

acquiring the total temperature acquired by a total temperature sensor at the current moment, and acquiring the static temperature according to the total temperature and the Mach number stored at the previous moment;

acquiring the sound velocity at the static temperature according to the static temperature;

and acquiring the ground speed of the current moment obtained by resolving by the inertial navigation system, and acquiring the Mach number of the current moment according to the ground speed and the sound speed.

6. The system of claim 5, wherein the air data computer is specifically configured to:

according to the total temperature T_tAnd Mach number M stored at the last moment, and calculating the static temperature T by adopting the following formula_S；

Wherein k is the adiabatic index of air; and N is the total temperature recovery rate of the total temperature sensor.

7. The system of claim 6, wherein the air data computer is specifically configured to:

according to the static temperature T_SObtaining the static temperature T by adopting the following formula_SDownward speed of sound c;

wherein R is the gas constant of air.

8. The system of claim 7, wherein the air data computer is specifically configured to:

will the ground speed V_GroundThe Mach number is taken as the ratio to the speed of sound c.

Technical Field

The invention belongs to the technical field of atmospheric data acquisition, and particularly relates to a method and a system for acquiring Mach number during full-pressure failure.

Background

The Mach number is the ratio of the true airspeed of the aircraft to the speed of sound at the altitude at which it is flying, and characterizes the effect of air compressibility. The Mach number is an important atmospheric parameter in the flight process of the airplane and is related to the maximum use speed limit of the airplane, and the Mach number is often used for correcting atmospheric parameters of the barometric altitude and has large influence on the flight performance and safety. Therefore, obtaining the mach number of the airplane is very important to the performance and the safety of the airplane.

The Mach number is obtained by calculation according to atmospheric static pressure and dynamic pressure, and the static pressure and the dynamic pressure are obtained by measurement of a full static pressure system.

However, when the full-pressure system is frozen or blocked, dynamic pressure failure can be caused, and further mach number failure is caused, so that data such as static pressure, air pressure height and static temperature output by the atmospheric data system are seriously deviated from real values, and flight safety is endangered.

Disclosure of Invention

The purpose of the invention is:

the method and the system for acquiring the Mach number in the full-voltage failure are provided, and the problem that the Mach number cannot be acquired in the full-voltage system failure is solved.

The technical scheme of the invention is as follows:

the invention provides a method for acquiring Mach number during full-voltage failure, which comprises the following steps:

acquiring the total temperature acquired by a total temperature sensor at the current moment, and acquiring the static temperature according to the total temperature and the Mach number stored at the previous moment;

acquiring the sound velocity at the static temperature according to the static temperature;

and acquiring the ground speed of the current moment obtained by resolving by the inertial navigation system, and acquiring the Mach number of the current moment according to the ground speed and the sound speed.

Optionally, the obtaining the static temperature includes:

according to the total temperature T_tAnd Mach number M stored at the last moment, and calculating the static temperature T by adopting the following formula_S；

Wherein k is the adiabatic index of air; and N is the total temperature recovery rate of the total temperature sensor.

Optionally, the acquiring the sound speed at the quiet temperature includes:

according to the static temperature T_SObtaining the static temperature T by adopting the following formula_SDownward speed of sound c;

wherein R is the gas constant of air.

Optionally, the obtaining the mach number of the current time according to the ground speed and the sound speed includes:

will the ground speed V_GroundThe Mach number is taken as the ratio to the speed of sound c.

A second aspect of the present invention provides a system for acquiring a mach number during full-pressure failure, including: a total temperature sensor, an inertial navigation system and an air data computer; wherein the atmospheric data computer is to:

acquiring the total temperature acquired by a total temperature sensor at the current moment, and acquiring the static temperature according to the total temperature and the Mach number stored at the previous moment;

acquiring the sound velocity at the static temperature according to the static temperature;

and acquiring the ground speed of the current moment obtained by resolving by the inertial navigation system, and acquiring the Mach number of the current moment according to the ground speed and the sound speed.

Optionally, the atmosphere data computer is specifically configured to:

according to the total temperature T_tAnd Mach number M stored at the last moment, and calculating the static temperature T by adopting the following formula_S；

Wherein k is the adiabatic index of air; and N is the total temperature recovery rate of the total temperature sensor.

Optionally, the atmosphere data computer is specifically configured to:

according to the static temperature T_SObtaining the static temperature T by adopting the following formula_SDownward speed of sound c;

wherein R is the gas constant of air.

Optionally, the atmosphere data computer is specifically configured to:

will the ground speed V_GroundThe Mach number is taken as the ratio to the speed of sound c.

The invention has the advantages that:

the system comprises an atmospheric data computer, a total static pressure system, a total temperature sensor, an attack angle sensor and an inertial navigation system. The required equipment is the existing equipment of the airplane, no additional equipment is needed, and the system is simple to implement. Using Mach number M in combination with the total temperature T collected_tCalculating the static temperature T_S(ii) a According to static temperature T_SObtaining the static temperature T_SThe lower sound velocity c is the inertial navigation ground velocity V introduced by the air data computer by utilizing the principle that the vacuum velocity is equal to the inertial navigation ground velocity under the condition of no wind in the air and the vacuum velocity is close to the inertial navigation ground velocity under the condition of small wind speed_GroundAccording to the ground speed V_GroundThe Mach number M is estimated according to the ratio of the Mach number to the sonic speed c and the dynamic pressure q_cStatic pressure P_SIn relation to Mach number M, obtaining dynamic pressure q_cThe realization algorithm is simple and reliable, and the workload of change is low.

Drawings

FIG. 1 is a schematic diagram of a Mach number acquisition system for full-voltage failure according to the present invention;

fig. 2 is a schematic flow chart of a method for acquiring a mach number in full-pressure failure according to the present invention.

Detailed Description

The present invention will be explained in detail with reference to the accompanying drawings.

Fig. 1 is a schematic architecture diagram of a system for acquiring a mach number during full-pressure failure provided by the present invention, and fig. 2 is a schematic flow chart of a method for acquiring a mach number during full-pressure failure provided by the present invention; as shown in fig. 1 and 2, the mach number obtaining system in full-voltage failure provided by the present invention includes: an atmosphere data computer, a total temperature sensor and an inertial navigation system. Optionally, the system further comprises: a full hydrostatic system; the total static pressure system comprises a total pressure system and a static pressure system.

Under normal conditions of the full-pressure system, the atmosphere data computer receives the full pressure P of the full-static pressure system_tStatic pressure P_SReceiving the total temperature T of the total temperature sensor_tAnd receiving the corrected front attack angle alpha of the attack angle sensor. Obtaining dynamic pressure q according to the difference value of total pressure and static pressure_cI.e. q_c＝P_t-P_SAnd further calculating to obtain an indicated airspeed V_i(ii) a According to dynamic pressure q_cStatic pressure P_SObtaining a Mach number M; according to the total temperature T_tMach number M obtaining static temperature T_S(ii) a And further correcting the static pressure P by using the obtained Mach number M_SAngle of attack alpha, based on corrected static pressure P_SThe gas pressure height Hb is calculated.

Under the condition of full-pressure system failure, the atmospheric data computer can only receive and normally solve the static pressure P of the full-static-pressure system_SReceiving the total temperature T of the total temperature sensor_tAnd receiving the corrected front attack angle alpha of the attack angle sensor. At this point, the air data computer cannot obtain an effective full pressure P due to a full pressure system failure_tWill result in dynamic pressure q_cMach number M, indicated airspeed V_iStatic temperature T_SEtc. are invalid. For the situation, the calculation method of the invention is specifically as follows:

the method comprises the following steps:

the static temperature T is calculated by combining the acquired total temperature Tt with the Mach number M obtained by the method during the first calculation of the air data computer and the Mach number M obtained by the invention during the second iteration_SAt a static temperature of T_SThe calculation method is as follows:

in the formula: t is_t-total temperature (K); k-adiabatic index (air 1.4); m is Mach number; N-Total temperature recovery (obtained from the total temperature sensor characteristics employed).

Step two:

according to static temperature T_SObtaining the static temperature T_SThe following sound velocity c, the method is as follows:

where k is the adiabatic index (air 1.4); r-specific gas constant 287.05287 (unit: m)³/K·s₂)；T_SThe resting temperature (unit: K).

Step three:

ground speed V calculated by receiving inertial navigation system through air data computer_GroundObtain, utilize the ground speed V_GroundThe mach number M is estimated as the ratio to the speed of sound c. Mach number M is defined as follows:

wherein, V_Ground-inertial navigation ground speed; and c is the speed of sound. And the ground speed V of the inertial navigation system_GroundThe ground speed of other devices with the same principle can be used instead.

Using the obtained Mach number M vs. static pressure P_SAnd the attack angle alpha and other data are corrected to obtain more accurate parameters.

Step four:

according to the Mach number M obtained, according to the dynamic pressure q_cStatic pressure P_SIn relation to Mach number M, obtaining dynamic pressure q_cThe definition is as follows:

when M is less than or equal to 1:

when M > 1:

wherein, P_SAtmospheric static pressure (unit: kPa); m is Mach number; k-adiabatic index (air 1.4).

According to the obtained dynamic pressure q_cThe indicated airspeed V can be calculated_i。

And repeating the first step, the second step, the third step and the fourth step to obtain all atmospheric parameters under the condition of the fault of the full-pressure system.