CN114624999A - A kind of solid rocket first stage separation body fall area control system and method - Google Patents

Abstract

The invention relates to a system and a method for controlling the drop area of a first-stage separation body of a solid rocket. The control system includes a grid rudder control system and a measurement and control communication system; the grid rudder control system includes an inertial navigation controller, an integrated controller, and a steering gear. and battery; the measurement and control communication system includes a GNSS/BD2 receiving device, an editor, a telemetry launching device and a battery; compared with the traditional offline binding standard ballistic method, the integration process of the online ballistic planning method provided by the present invention is based on the separation time The ballistic planning is carried out in the actual flight state, and the initial value of the integral is more accurate, so the obtained standard ballistic trajectory is closer to the actual flight environment, and the scope of the landing area is narrowed. Using the ballistic online planning method, the nearest target landing point can be selected for ballistic planning according to the actual flight state, which can greatly reduce the pressure on the guidance and control system, and improve the safety and flight quality of the flight process.

Description

A kind of solid rocket first stage separation body fall area control system and method

technical field

The invention relates to the field of solid rocket drop zone control design, in particular to a solid rocket first-stage separation body drop zone control system and method.

Background technique

After the traditional multi-stage solid rocket is launched, the first-stage engine separates and falls after the end of work, and finally falls to the ground or inland. Since most of my country's solid carrier rocket launch bases are inland, the falling points of the separated bodies are all on the land. Although the rockets are planned and designed in ballistics, the separation area will be considered to avoid covering railways, highways, villages and cities. The distribution of the drop points is large, and there is still the possibility of threatening the safety of residents' lives and property. At present, the usual practice is to control the drop zone of the separation body by adjusting the flight trajectory of the rocket, controlling the first-stage separation height, and the separation attitude. However, the disadvantage of this method is that the rocket will lose part of its carrying capacity, and the ability to control the drop area through this passive control method is limited. When it is impossible to avoid the first-level detachment from falling into the village, a large amount of manpower needs to be invested by the local relevant departments. Material and financial resources to evacuate residents.

When the first-stage flight state of the rocket deviates greatly from the standard ballistic state of the pre-launch binding, there will be a large deviation in the initial position and velocity of the first-stage separation body, and the initial position and velocity are used as the initial value of the integration, and the deviation of the initial value of the integration will pass through the integration process. , passed to the end point of the integral, so the traditional offline binding ballistic method has a large distribution of landing points, and the difference between the actual flight environment and the offline ballistic calculation environment will bring more pressure to the rocket guidance control system.

In order to solve the problems of safety and adaptability of the first-stage separation body drop zone, and at the same time for the deficiencies of passive drop zone control methods, the present invention proposes a solid rocket first-stage separation body drop zone control system and method.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a solid rocket first-stage separation body drop zone control system and method, which can actively control the first-stage separation body drop zone and improve the safety of rocket launch and the adaptability to tasks.

A drop zone control system for a first-stage separation body of a solid rocket, the first-stage separation body includes a grid rudder, and the control system includes a grid rudder control system and a measurement and control communication system;

The grid rudder control system includes an inertial navigation controller, an integrated controller, a steering gear and a battery; the inertial navigation controller can be sensitive to the attitude information of the first-level separation body, carry out ballistic planning and stability calculation, and output rudder control instructions; integrated control The controller receives the control instructions sent by the inertial navigation controller, completes the steering gear control and timing control, and makes the grid rudder act as required; the battery is used to supply power to each device;

The measurement and control communication system includes a GNSS/BD2 receiving device, an acquisition and editor, a telemetry transmitter and a battery; the GNSS/BD2 receiving device is used to receive GPS/BD2 satellite signals and measure the separated in vitro ballistics; the main function of the acquisition and editor is to The position information in the body of the stage separation and the information in the inertial navigation controller are unified and framed; the telemetry transmitter and the telemetry transmitting antenna modulate, amplify and download the telemetry information; the battery is used to supply power to each device.

Further, the grid rudder control system adopts a dual bus architecture, the control bus mainly transmits control instructions, and the test bus mainly transmits control instructions and telemetry information of the control bus. isolation.

Further, the stand-alone equipment of the grid rudder control system and the measurement and control communication system are installed in the tail section of the cabin to avoid the equipment being separated and heated by the heat flow during the falling process.

The present invention also provides a method for controlling the first-stage separation body drop area of a solid rocket, which adopts the above-mentioned control system, and specifically includes two control stages: Stage 1 is the attitude stabilization stage, and in the initial stage after the first-stage separation, the attitude angle and the attitude angle are passed through. The double-loop feedback correction network of the rate controls the flipping of the separation body to make it return to a stable flight state;

Stage 2 is the re-entry flight stage. The control system effectively controls the flight of the rocket body through the feedback of attitude angle (ie pitch angle, yaw angle and roll angle), so that the separation body flies according to the planned re-entry trajectory.

According to the zero angle of attack and zero sideslip state of the separation body, the reference landing point is obtained, and then the distance between the reference landing point and each candidate landing point bound before shooting is judged, and the nearest candidate landing point is selected as the target landing point. Calculate the flight angle of attack and sideslip angle required by the separation body to reach the target landing point, so as to design the real-time reentry trajectory of the first separation body.

Further, the method for judging from stage 1 to stage 2 is: when the three attitude rates of the first-level separation body sensitive to the inertial navigation controller are all less than 5°/s for 2 s, it is judged that the flight of the separation body enters stage 2 from stage 1.

Further, the real-time re-entry ballistic design method of the first-level separation body is:

Since the primary separation body has no thrust during flight, and ignores the influence of aerodynamic ablation, it is considered that the mass does not change during flight, so the equation of motion during flight is expressed as:

为v的导数，

为r的导数；In the formula, v is the velocity vector under the launch coordinate system, r is the position vector under the launch system,

is the derivative of v,

is the derivative of r;

g is the gravitational acceleration vector of the earth, which is only related to the geocenter vector radius R, and the geocenter vector radius can be obtained by R=r+Re ₀ ;

C is the acceleration vector caused by the aerodynamic force, which is determined by the flight angle of attack α and the sideslip angle β;

选取距离最小的为目标落点(x_b,y_b)，根据当前飞行状态，通过迭代求解得到到目标落点所需的攻角α和侧滑角β，从而确定目标再入弹道。The fourth-order Longge-Kutta integration method with variable step length is adopted, the current actual flight speed and position are used as the initial value of the integration, and the integration termination condition is that the flight height is zero. According to the control strategy of zero attack angle and zero sideslip angle, we can obtain The coordinates of the integration end point (x ₀ , y ₀ ), assuming that there are n landing points to be selected, the coordinates are: (x ₁ , y ₁ )...(x _i , y _i )...(x _n , y _n ), then the distance between the reference landing point and the i-th candidate landing point can be expressed as

The target landing point (x _b , y _b ) is selected with the smallest distance. According to the current flight state, the attack angle α and sideslip angle β required to reach the target landing point are obtained by iterative solution, so as to determine the target re-entry trajectory.

ψ₁、γ₁(俯仰角、偏航角和滚转角)，经过工具误差补偿计算、导航计算得到分离体姿态角对应的四元数，与程序姿态角对应四元数比较形成角偏差

Δψ₁、Δγ₁，角偏差通过校正网络的增益K₁校正；通过惯导控制器获取分离体的姿态角速率

(

分别为

ψ₁、γ₁求导)，经过校正网络的增益K₂以负反馈形式与增益后的角偏差合成控制指令

P_ψ、P_γ，形式如下：Further, stage 1 first obtains the attitude angle increment of the separated body through the inertial navigation controller

ψ ₁ , γ ₁ (pitch angle, yaw angle and roll angle), through tool error compensation calculation and navigation calculation, the quaternion corresponding to the attitude angle of the separated body is obtained, which is compared with the quaternion corresponding to the program attitude angle to form an angular deviation

Δψ ₁ , Δγ ₁ , the angular deviation is corrected by the gain K ₁ of the correction network; the attitude angular rate of the separated body is obtained through the inertial navigation controller

(

respectively

ψ ₁ , γ ₁ derivation), the gain K ₂ of the correction network is combined with the angular deviation after the gain in the form of negative feedback to synthesize the control command

P _ψ , P _γ , the form is as follows:

再通过栅格舵系统输出实际执行的舵偏

对一级分离体的姿态进行控制；The output pitch and yaw channel control commands are filtered, and the filtering algorithm is designed with a combination of notch filter and low-pass filter to attenuate the interference signal of the elastic vibration of the first-level separation body, so as to output the grid rudder rudder deflection command signal

Then output the actual rudder deflection through the grid rudder system

Control the attitude of the first-level separation body;

Further, the notch filter transfer function model is:

为陷波深度，陷波滤波器中心频率点根据一级分离体弹性运动固有频率进行选取，通过采用在相应阶次弹性固有频率附近设计多个陷波滤波器串联的方法实现对固有频率附近较大频率范围内的弹性运动幅值进行有效的衰减。低通滤波器在离散域中直接设计，使得在降低中频相位滞后的条件下，在陷波滤波器设计频率点以上的频率范围内实现幅值衰减滤波。where ω _j is the notch frequency,

For the notch depth, the center frequency point of the notch filter is selected according to the natural frequency of the elastic motion of the first-order separation body. Effective attenuation of elastic motion amplitudes over a large frequency range. The low-pass filter is directly designed in the discrete domain, so that the amplitude attenuation filtering can be realized in the frequency range above the design frequency point of the notch filter under the condition of reducing the phase lag of the intermediate frequency.

ψ₂、γ₂(俯仰角、偏航角和滚转角)，经过工具误差补偿计算、导航计算得到分离体姿态角对应的四元数，与程序姿态角对应四元数比较形成角偏差

Δψ₂、Δγ₂并滤波，滤波算法采用与阶段1相同的陷波滤波器和低通滤波器组合设计；校正网络为单环控制，输入为滤波后的角偏差，输出为栅格舵指令信号

最终通过栅格舵系统输出实际执行的舵偏

从而对一级分离体的姿态进行控制；Further, taking the pitch channel as an example, the phase 2 first obtains the attitude angle increment of the separated body through the inertial navigation controller.

ψ ₂ , γ ₂ (pitch angle, yaw angle and roll angle), through tool error compensation calculation and navigation calculation, the quaternion corresponding to the attitude angle of the separated body is obtained, which is compared with the quaternion corresponding to the program attitude angle to form an angular deviation

Δψ ₂ , Δγ ₂ are filtered in parallel, and the filtering algorithm adopts the same notch filter and low-pass filter combination design as in stage 1; the correction network is single-loop control, the input is the filtered angular deviation, and the output is the grid rudder command signal

Finally, the actual rudder deflection is output through the grid rudder system

Thereby, the attitude of the first-level separation body is controlled;

Further, the selection principle of the optional target landing point of the described pre-shooting binding is: if there are no railways, highways, villages and cities, etc. within the range of the first-level separation body landing zone, and the landing zone requirements are fully met, then the landing zone is selected. The center point is the target drop point; if there are a small number of railways, highways, villages and cities, etc. within the first-level separation area, in the principle of avoiding the above-mentioned locations, multiple target drop points are selected scattered within the drop area.

Compared with the traditional offline binding standard ballistic method, the integration process of the online ballistic planning method provided by the present invention is to carry out ballistic planning based on the actual flight state at the time of separation, and the initial value of the integration is more accurate, so the obtained standard ballistic trajectory is closer to the actual flight environment. It can effectively reduce the scope of the landing area; on the other hand, the online ballistic planning method can select the nearest target landing point for ballistic planning according to the actual flight status, especially when the actual flight status is greatly different from the standard status, it can be greatly reduced. The pressure on the guidance and control system improves the safety and flight quality of the flight process.

Description of drawings

Fig. 1 is a schematic diagram of a first-level separator;

Figure 2 is a block diagram of the attitude control principle of stage 1;

Figure 3 is a block diagram of the attitude control principle in stage 2.

Explanation of symbols: 1- first stage engine, 2- tail section, 3- grid rudder.

Detailed ways

The invention provides a solid rocket first-stage separation body fall area control system, which includes a grid rudder control system and a measurement and control communication system. The grid rudder control system includes an inertial navigation controller, an integrated controller, a steering gear and a battery, and the measurement and control communication system includes a GNSS/BD2 receiving device, an acquisition and editor, a telemetry transmitter and a battery.

The first-level separation body refers to the separation body with a grid rudder in the tail section, as shown in Figure 1;

In order to avoid heat flow heating in the process of separation and falling, the single equipment of the grid rudder control system and the measurement and control communication system are installed in the tail section;

The grid rudder control system adopts a dual-bus structure. The control bus mainly transmits control instructions, and the test bus mainly transmits control instructions and telemetry information of the control bus. The two buses are completely isolated physically, and are redundant and hot backup for each other. The control system supplies power; the inertial navigation controller has the functions of the inertial group and the central computer, which can be sensitive to the attitude information of the first-level separated body, carry out ballistic planning and stable calculation, and output steering control instructions; the main function of the integrated controller is to receive inertial navigation control. Control commands sent from the controller to complete the steering gear control and timing control, so that the grid rudder acts as required;

The measurement and control communication system adopts the ground-based telemetry and GPS/BD2 external measurement scheme, and the measurement and control communication system is powered by the battery; the GNSS/BD2 receiving device is used to receive GPS/BD2 satellite signals and measure the separated external ballistics; the main functions of the acquisition and editor are: The position information in the first-level separation body and the information in the inertial navigation controller are unified and framed; the telemetry transmitter and the telemetry transmitting antenna modulate, amplify and download the telemetry information.

The control includes two stages: Stage 1 is the attitude stabilization stage, that is, the initial stage after the first-level separation. In this stage, the separation body is affected by the separation disturbance, and the motion state is unstable. Therefore, it first restores the stable flight state through a period of attitude control. ; Stage 2 is the re-entry flight stage. In this stage, the control capability covers the interference force, and the control system can effectively control the flight of the arrow body so that the separation body flies according to the planned re-entry trajectory. The two-stage judgment method is as follows: when the three attitudes (pitch, yaw and roll) rates of the three attitudes (pitch, yaw and roll) of the first-stage separation body sensitive to the inertial navigation controller are all less than 5°/s for 2 s, it is judged that the first-stage separation body flies by the stage. 1 goes to stage 2.

The drop zone control method specifically includes the ballistic online planning method and the attitude control method.

The online ballistic planning method is: in stage 1, the online calculation and planning of the ballistic of the separation body is not carried out. When it is judged that the flight enters stage 2, starting from the starting time, every interval is based on the current flight position and speed of the first separation body. Calculate the reference landing point in real time, select the target landing point based on the matching degree between the reference landing point and the target landing point bound before firing, and then plan the re-entry flight trajectory in real time based on the target landing point.

The selection principle of the optional target landing point for binding before shooting is as follows: if there are no railways, highways, villages and cities, etc. within the range of the first-level separation body landing area, and the requirements of the landing area are fully met, the center point of the landing area is selected as the target landing area. If there are a small number of railways, highways, villages and cities, etc. within the first-level separation area, in accordance with the principle of avoiding the above-mentioned locations, a plurality of candidate drop points will be selected scattered within the area.

The planning method of the re-entry flight trajectory is to determine the current position and flight speed through the inertial navigation controller at regular intervals after the first-stage separation body resumes stable flight, and integrate according to the zero attack angle and zero sideslip state of the first-stage separation body. Obtain the reference landing point, then judge the distance between the reference landing point and each candidate landing point bound before firing, select the nearest candidate landing point as the target landing point, and calculate the flight angle of attack and sideslip of the first-level separation body accordingly. angle, so as to design the real-time reentry trajectory of the primary separation body.

Specifically, the real-time reentry ballistic design method of the primary separation body is as follows:

The equation of motion during flight is expressed in the launch coordinate system as:

为v的导数，

为r的导数；In the formula, v is the velocity vector under the launch coordinate system, r is the position vector under the launch system,

is the derivative of v,

is the derivative of r;

g is the gravitational acceleration vector of the earth, which is only related to the center vector radius R, which is obtained by R=r+Re ₀ ;

C is the acceleration vector caused by the aerodynamic force, which is determined by the flight angle of attack α and the sideslip angle β;

Assuming that there are n points to be selected, and the coordinates are: (x ₁ , y ₁ )...(x _i , y _i )...(x _n , y _n ), the fourth-order dragon with variable step size is adopted Kuta integral method:

Suppose the problem to be solved is

q(t ₀ )=q ₀

为q的导数，t为积分时刻；q is the integral state quantity,

is the derivative of q, and t is the integration time;

Select the appropriate integration step size h according to the solution accuracy, and its iterative process can be expressed as:

选取距离最小的落点作为目标落点(x_b,y_b)，根据当前飞行状态，通过迭代求解得到满足目标落点坐标(x_b,y_b)的攻角α和侧滑角β，从而确定目标再入弹道。The initial condition q ₀ of the integration is the current flight position r, the velocity vector v, and j represents the moment. The position and velocity of the subsequent flight moment can be obtained through the above iterations, thereby determining the flight trajectory. Taking the current actual flight speed and position as the initial value of the integration, the integration termination condition is that the flight height is zero (that is, the first-stage separation body falls to the ground). According to the control strategy of zero attack angle and zero sideslip angle, the above integration method can be used. Obtain the coordinates of the integration end point (x ₀ , y ₀ ); assuming that there are n landing points to be selected, the coordinates are: (x ₁ , y ₁ )...(x _i , y _i )...(x _n , y _n ), then the distance between the reference landing point and the i-th candidate landing point can be expressed as

Select the landing point with the smallest distance as the target landing point (x _b , y _b ), and obtain the angle of attack α and the sideslip angle β that satisfy the coordinates of the target landing point (x _b , y _b ) through the iterative solution according to the current flight state, so that Determine the target reentry trajectory.

The attitude control method is as follows: the main purpose of the phase 1 attitude control is to stabilize the flight attitude of the primary separation body. During separation, the Mach number is high, and the first-stage separation body is in a statically unstable state. It will produce a flip motion when it is disturbed by separation. At this time, the attitude control uses the double-loop feedback correction network of attitude angle and attitude angular rate to flip the first-stage separation body. Control, as the control ability gradually increases and covers the interference force, the first-level separation body will return to a stable flight state.

经过工具误差补偿计算、导航计算得到一级分离体姿态角对应的四元数并与程序姿态角对应四元数比较形成角偏差

角偏差通过校正网络的增益K₁校正；由惯导控制器敏感分离体的俯仰角速率

通过校正网络的增益K₂以负反馈形式与增益后的俯仰角偏差

合成控制指令，形式如下：Specifically, the dual-loop feedback correction network and control principle, taking the pitch channel as an example, the control principle block diagram is shown in Figure 2, when the pitch angle rate is large (>5°/s), the sensitive separation body of the inertial navigation controller is pitched Angular increment

After tool error compensation calculation and navigation calculation, the quaternion corresponding to the attitude angle of the first-level separated body is obtained and compared with the quaternion corresponding to the program attitude angle to form an angular deviation

The angular deviation is corrected by the gain K ₁ of the correction network; the pitch angle rate of the separation body is sensitive to the inertial navigation controller

By correcting the gain _K of the network in the form of negative feedback and the pitch angle deviation after the gain

Synthesized control instructions in the following form:

再通过栅格舵系统输出实际执行的舵偏

对一级分离体的姿态进行控制。The filtering algorithm is designed with a combination of notch filter and low-pass filter to attenuate the interference signal of the elastic vibration of the first-order separator, so as to output the control command as a grid rudder deflection command signal

Then output the actual rudder deflection through the grid rudder system

Control the posture of the primary separation body.

Specifically, the transfer function model of the notch filter is:

为陷波深度(ξ₁具体是分离体的固有弹性阻尼比，ξ₂是设计阻尼比，相除为陷波深度)，陷波滤波器中心频率点根据一级分离体弹性运动固有频率进行选取，通过采用在相应阶次弹性固有频率附近设计多个陷波滤波器串联的方法实现对固有频率附近较大频率范围内的弹性运动幅值进行有效的衰减；低通滤波器在离散域中直接设计，使得在降低中频相位滞后的条件下，在陷波滤波器设计频率点以上的频率范围内实现幅值衰减滤波。where ω _j is the notch frequency,

is the notch depth (ξ ₁ is the inherent elastic damping ratio of the separation body, ξ ₂ is the design damping ratio, divided by the notch depth), the center frequency of the notch filter is selected according to the natural frequency of the elastic motion of the first-order separation body , by using the method of designing multiple notch filters in series near the natural frequency of the corresponding order to achieve effective attenuation of the elastic motion amplitude in a large frequency range near the natural frequency; the low-pass filter directly in the discrete domain It is designed so that the amplitude attenuation filtering can be realized in the frequency range above the design frequency point of the notch filter under the condition of reducing the phase lag of the intermediate frequency.

经过工具误差补偿计算、导航计算得到一级分离体姿态角对应的四元数，与程序姿态角对应四元数比较形成角偏差

并滤波，滤波算法同样采用陷波滤波器和低通滤波器组合设计；校正网络为单环控制，输入为滤波后的

输出为栅格舵指令信号

最终通过栅格舵系统输出实际执行的舵偏

从而对一级分离体的姿态进行控制。The main purpose of the phase 2 attitude control is to adjust the attitude of the separated body to follow the re-entry trajectory planned online so as to control the landing zone. At this stage, attitude angle feedback control is adopted. Taking the pitch channel as an example, the control principle block diagram of the attitude angle feedback is shown in Figure 3. The inertial navigation controller outputs the pitch angle increment.

After tool error compensation calculation and navigation calculation, the quaternion corresponding to the attitude angle of the first-level separated body is obtained, and the quaternion corresponding to the program attitude angle is compared to form an angular deviation

and filtering, the filtering algorithm is also designed with a combination of notch filter and low-pass filter; the correction network is single-loop control, and the input is the filtered

The output is the grid rudder command signal

Finally, the actual rudder deflection is output through the grid rudder system

Thereby, the posture of the first-level separation body is controlled.

Claims (10)

1. a solid rocket one-stage separation body fall area control system, described first-stage separation body comprises grid rudder, it is characterized in that, described control system comprises grid rudder control system and measurement and control communication system; The grid rudder control system includes an inertial navigation controller, an integrated controller, a steering gear and a battery; the inertial navigation controller can be sensitive to the attitude information of the first-level separation body, carry out ballistic planning and stability calculation, and output rudder control instructions; integrated control The controller receives the control commands sent by the inertial navigation controller, and completes the steering gear control and sequence control, so that the grid rudder acts as required; the battery is used to supply power to each device; The measurement and control communication system includes a GNSS/BD2 receiving device, a collector and editor, a telemetry transmitting device and a battery; the GNSS/BD2 receiving device is used to receive GPS/BD2 satellite signals and measure the ballistics in vitro; The information and the information in the inertial navigation controller are unified and framed; the telemetry transmitter and the telemetry transmitting antenna modulate, amplify and download the telemetry information; the battery is used to supply power to each device. 2. a kind of solid rocket one-stage separation body drop zone control system according to claim 1, is characterized in that, described grid rudder control system, adopts dual bus architecture, control bus transmits control instruction, test bus transmits control bus The two buses are redundant and hot backup for each other. 3. A solid rocket first-stage separation body drop zone control system according to claim 1, characterized in that, the stand-alone equipment of the grid rudder control system and the measurement and control communication system are all installed in the tail section. 4. A method for controlling the first-stage separation body fall area of a solid rocket, characterized in that, adopting the control system according to any one of claims 1-3, comprising two control stages: stage 1 is an attitude stabilization stage, and a stage 1 is an attitude stabilization stage. In the initial stage after the stage separation, the overturning of the separated body is controlled by the double-loop feedback correction network of attitude angle and attitude angular rate, so as to restore the stable flight state; Stage 2 is the re-entry flight stage. The control system effectively controls the flight of the rocket body through attitude angle feedback, so that the separation body flies according to the planned re-entry trajectory; The planning method of the re-entry trajectory is: according to the zero attack angle and zero sideslip state of the separation body, the reference landing point is obtained, and then the distance between the reference landing point and each candidate landing point bound before shooting is judged, and the nearest target landing point is selected. The landing point is selected as the target landing point, and the flight attack angle and sideslip angle required by the first-level separation body to the target landing point are calculated accordingly, so as to design the real-time reentry trajectory of the first-level separation body. 5. The method for controlling the drop zone of a solid rocket first-stage separation body according to claim 4, wherein the judgment method for entering stage 2 from stage 1 is: when the inertial navigation controller is sensitive to three kinds of first-stage separation bodies When the attitude angular rate is less than 5°/s for 2 s in a row, it is judged that the flight of the first-level separated body enters from stage 1 to stage 2. 6. a kind of solid rocket first-stage separation body drop zone control method according to claim 4, is characterized in that, the real-time re-entry ballistic design method of described first-stage separation body is: The equation of motion during flight is expressed in the launch coordinate system as:

In the formula, v is the velocity vector under the launch coordinate system, r is the position vector under the launch system,

is the derivative of v,

is the derivative of r; g is the gravitational acceleration vector of the earth, which is only related to the geocentric vector radius R, which is obtained by R=r+Re ₀ , and Re ₀ is the geocentric vector radius of the launch point; C is the acceleration vector caused by the aerodynamic force, which is determined by the flight angle of attack α and the sideslip angle β; The fourth-order Longge-Kutta integration method with variable step length is adopted, the current actual flight speed and position are used as the initial value of the integration, and the integration termination condition is that the flight height is zero. According to the control strategy of zero attack angle and zero sideslip angle, the Obtain the coordinates of the integration end point (x ₀ , y ₀ ); assuming that there are n landing points to be selected, the coordinates are: (x ₁ , y ₁ )...(x _i , y _i )...(x _n , y _n ), then the distance between the reference landing point and the i-th candidate landing point can be expressed as

Select the minimum distance as the target landing point (x _b , y _b ), and according to the current flight state, obtain the attack angle α and sideslip angle β that satisfy the target landing point coordinates (x _b , y _b ) through iterative solution, so as to determine the target Re-entry ballistic. 7. The method for controlling the drop zone of a solid rocket first-stage separation body according to claim 4, wherein the first stage 1 obtains the attitude angle increment of the separation body through the inertial navigation controller

ψ ₁ , γ ₁ , the quaternion corresponding to the attitude angle of the separated body is obtained through tool error compensation calculation and navigation calculation, and the quaternion corresponding to the attitude angle of the program is compared to form an angular deviation

Δψ ₁ , Δγ ₁ , the angular deviation is corrected by the gain K ₁ of the correction network; the attitude angular rate of the separated body is obtained through the inertial navigation controller

The gain K ₂ of the correction network is combined with the angular deviation after the gain in the form of negative feedback to synthesize the control command

P _ψ , P _γ , the form is as follows:

The output pitch and yaw channel control commands are filtered, and the filtering algorithm is designed with a combination of notch filter and low-pass filter to attenuate the interference signal of the elastic vibration of the first-level separation body, so as to output the grid rudder rudder deflection command signal

Then output the actual rudder deflection through the grid rudder system

Control the posture of the primary separation body. 8 . The method for controlling the drop zone of the first-stage separation body of a solid rocket according to claim 4 , wherein at first, the phase 2 obtains the attitude angle increment of the separation body through the inertial navigation controller. 9 .

ψ ₂ , γ ₂ , the quaternion corresponding to the attitude angle of the separated body is obtained through tool error compensation calculation and navigation calculation, and the angle deviation is formed by comparing with the quaternion corresponding to the program attitude angle

Δψ ₂ , Δγ ₂ , and then filter the pitch and yaw channel signals, the filtering algorithm is the same as that of stage 1; the correction network is single-loop control, the input is the filtered angular deviation signal, and the output is the grid rudder command signal

Finally, the actual rudder deflection is output through the grid rudder system

Thereby, the posture of the first-level separation body is controlled. 9. a kind of solid rocket first-stage separation body drop zone control method according to claim 4, is characterized in that, the selection principle of the optional target drop point of described pre-shooting binding is: if the range of the first-stage separation body drop zone If there are no railways, highways, villages and urban buildings in the area, and the requirements of the settlement area are fully met, the center point of the settlement area is selected as the target place; , in order to avoid the above-mentioned locations as the principle, select multiple target drop points scatteredly within the drop zone. 10. a kind of solid rocket one-stage separation body fall area control method according to claim 7, is characterized in that, described notch filter transfer function model is:

where ω _j is the notch frequency,

For the notch depth, the center frequency point of the notch filter is selected according to the natural frequency of the elastic motion of the first-order separation body. The elastic motion amplitude in a large frequency range is effectively attenuated; the low-pass filter is directly designed in the discrete domain, so that the amplitude can be realized in the frequency range above the design frequency point of the notch filter under the condition of reducing the phase lag of the intermediate frequency. Value attenuation filter.

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