Design method for self-oscillation suppression network of carrier rocket in vertical state

Abstract

The invention provides a design method for a self-excited oscillation suppression network of a carrier rocket in a vertical state. The design method mainly comprises construction of a dynamic model of the carrier rocket in the vertical state and a self-excited oscillation suppression method of the carrier rocket in the vertical state. The invention provides a carrier rocket self-excited oscillation suppression method aiming at a self-excited oscillation phenomenon occurring in a target range test when a carrier rocket is in a vertical state. Firstly, a vertical state carrier rocket dynamic model is established; frequency domain analysis is carried out based on the dynamic model; and finally, carrying out jitter elimination network design and time domain simulation verification. The method can effectively solve the self-oscillation phenomenon in the carrier rocket vertical state target range test, eliminates the influence of the carrier rocket periodic jitter on the rocket loading product, and effectively ensures the rocket ground test and take-off safety.

Description

Technical Field

[0001] The invention relates to a design method for a self-excited oscillation suppression network of a launch vehicle in an erected state, and belongs to the field of launch vehicle control. Background Art

[0002] Many launch vehicles are tested vertically at the range. When the command polarity test, the stability system zero position test, or the attitude control of the servo system before takeoff is carried out at the range, the rocket body may experience self-excited oscillation under the stimulation of the engine nozzle swing, that is, the launch vehicle structure itself experiences periodic jitter. If self-excited oscillation occurs before takeoff, it is likely to affect the rocket's takeoff drift and the safety of leaving the tower.

[0003] Since the launch vehicle is in an upright state at the test site, its modal frequency, vibration mode and engine working state are inconsistent with the actual flight state, resulting in large differences in the dynamic parameters of the two states. For example, the rocket engine in the ground state is in an unignited state, while the rocket engine in the flight state is in a normal working state. Therefore, after the attitude control loop is connected for ground testing at the test site, the correction network designed based on the flight state is likely to have insufficient attenuation of the elastic vibration signal and cannot adapt to the ground test state. Summary of the invention

[0004] The technical problem to be solved by the present invention is: to overcome the shortcomings of the prior art and provide a method for designing a self-excited oscillation suppression network for a launch vehicle in an upright state, so as to solve the self-excited oscillation phenomenon occurring in the range test of the launch vehicle in an upright state, eliminate the influence of the periodic vibration of the launch vehicle on the arrow loading product, and effectively ensure the safety of the ground test and take-off of the launch vehicle.

[0005] The technical solution of the present invention is: a method for designing a self-excited oscillation suppression network for a launch vehicle in an erected state, the method comprising the following steps:

[0006] According to the constraints and stress state of the rocket in the erected state, the dynamic model of the launch vehicle in the erected state is established;

[0007] Based on the dynamic model of the launch vehicle in the upright state, the state space of the attitude control system of the rocket in the upright state is constructed;

[0008] The state space of the attitude control system of the vertical rocket is transformed by pull-type, and the open-loop transfer functions of the pitch channel, yaw channel and roll channel of the attitude control system of the vertical rocket are obtained;

[0009] The open-loop transfer functions of the pitch channel, yaw channel and roll channel of the upright rocket attitude control are plotted into open-loop rocket body characteristic Bode diagrams. Based on the open-loop rocket body characteristic Bode diagrams, the pitch channel de-bouncing network, yaw channel de-bouncing network and roll channel de-bouncing network are designed to make the attitude control system meet the margin index requirements.

[0010] Preferably, the pitch channel de-jitter network, the yaw channel de-jitter network and the roll channel de-jitter network respectively perform low-pass filtering on the control quantities obtained by the PD control method of the pitch channel, yaw channel and roll channel of the attitude control system, and output the pitch, yaw and roll channel control swing angles.

[0011] Preferably, the transfer functions of the pitch channel de-jitter network, the yaw channel de-jitter network and the roll channel de-jitter network are composed of a plurality of second-order link filters, and are in the following form:

[0012]

[0013] Among them, Ω j is the pole second-order link circular frequency, ζ j is the damping ratio of the second-order link at the pole, Ω' k is the zero-point second-order link circular frequency, ζ' k is the damping ratio of the zero-point second-order link, and M and K are both integers.

[0014] Preferably, the dynamic model of the launch vehicle in the upright state is:

[0015]

[0016] in:

[0017] q i represents the i-th order generalized displacement of the arrow body, i = 1, 2, ..., n, n represents the total order of the mode;

[0018] represents the i-th order generalized velocity of the arrow body;

[0019] represents the i-th order generalized acceleration of the arrow body;

[0020] ω i represents the i-th order elastic circular frequency of the arrow body;

[0021] ξ i represents the i-th order elastic damping ratio of the rocket body;

[0022] D″ ψ_3i , D″ γ_3i They represent the i-th order elastic generalized force coefficients corresponding to the inertial forces of the engine nozzle swing in the pitch, yaw and roll channels respectively;

[0023] R zi (x GZ ), R zi (x ST ) represent the i-th order elastic rotation angle in the Z direction at the inertial group and the rate gyro respectively;

[0024] R yi (x GZ ), R yi (x ST ) represent the i-th order elastic rotation angle in the Y direction at the inertial group and the rate gyro respectively;

[0025] R yi (x GZ ), R yi (x ST ) represent the i-th order elastic rotation angle in the X direction at the inertial group and the rate gyro respectively;

[0026] Respectively represent the angular velocity measured in the Z direction by the inertial group and the rate gyro;

[0027] They represent the angular velocity measured in the Y direction by the inertial group and the rate gyro respectively;

[0028] They represent the angular velocity measured in the X direction by the inertial group and the rate gyro respectively;

[0029] They represent the equivalent angular acceleration of the pitch, yaw and roll channel engine nozzle respectively.

[0030] Preferably, the state space of the upright posture control system is:

[0031]

[0032] in, is the rocket state vector, including the generalized displacement and generalized velocity of the elastic mode of the rocket body;

[0033] A=diag(A i ),

[0034] diag() is a diagonal matrix function;

[0035]

[0036] C=[C 1 C 2 … C n ],

[0037] κ=z, represents the pitch channel, κ=y, η=ψ represents the yaw channel, κ=x, η=γ represents the roll channel, λ is the coefficient defined by the output matrix C that distinguishes the three channels. For the pitch channel and the roll channel, λ=1, and for the yaw channel, λ=2.

[0038] Preferably, the calculation formulas of the open-loop transfer functions of the pitch, yaw, and roll channels are as follows:

[0039]

[0040]

[0041] Where s represents the complex frequency of the Lassen transformation, κ = z, represents the pitch channel, κ=y, η=ψ represents the yaw channel, κ=x, η=γ represents the roll channel, and E is the unit matrix;

[0042] They represent the transfer functions of the pitch, yaw, and roll channel servo equivalent swing angles obtained from the state space to the attitude angular rate at the inertial group;

[0043] They represent the transfer functions of the pitch, yaw, and roll channel servo equivalent swing angles obtained from the state space to the attitude angular rate at the rate gyro;

[0044] Respectively represent the static amplification factors of pitch, yaw and roll attitude angle channels;

[0045] Respectively represent the dynamic amplification factors of pitch, yaw and roll attitude angular rate channels;

[0046] W GZ (s), W ST (s) represent the transfer functions of the inertial group and rate gyro, respectively;

[0047] W sf (s) represents the servo transfer function.

[0048] Preferably, the pitch, yaw, and roll channel debounce networks meet the following conditions:

[0049]

[0050] in, W jzψ (s), W jzγ (s) are the transfer functions of the pitch, yaw, and roll channel debounce networks, respectively; L zb Represents the amplitude margin index, are the open-loop transfer functions of the pitch, yaw, and roll channels, respectively.

[0051] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0052] (1) Aiming at the self-excited oscillation phenomenon that occurs during the range test of the launch vehicle in the upright state, the present invention establishes an upright state dynamic model and reveals the cause of the rocket's self-excited oscillation.

[0053] (2) Aiming at the self-excited oscillation phenomenon of a launch vehicle in an upright state, the present invention proposes a design method for a self-excited oscillation suppression network for a launch vehicle in an upright state, thereby eliminating the influence of the periodic vibration of the launch vehicle's own structure on the rocket loading products, and effectively ensuring the safety of the rocket's ground test and take-off. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 The present invention is a flowchart of the simulation verification of the attitude control system of a launch vehicle in an upright state.

[0055] Figure 2 The present invention is a flowchart of the method for constructing a dynamic model of a launch vehicle in an upright state and suppressing self-excited oscillations according to an embodiment of the present invention.

[0056] Figure 3 It is the attitude angular rate deviation of the three channels of the embodiment of the present invention (without adopting the de-jitter network).

[0057] Figure 4 These are the servo swing angle instructions for 4 units according to the embodiment of the present invention (without adopting a debouncing network).

[0058] Figure 5 It is the three-channel attitude angle deviation (using the de-jitter network) of the embodiment of the present invention.

[0059] Figure 6 These are the servo swing angle instructions for 4 sets according to the embodiment of the present invention (using a de-jitter network). DETAILED DESCRIPTION

[0060] The present invention will be described in further detail below.

[0061] The present invention provides a method for constructing a dynamic model of a launch vehicle in an upright state and suppressing self-excited oscillation, and the steps are as follows:

[0062] According to the constraints and stress state of the rocket in the erected state, the dynamic model of the launch vehicle in the erected state is established;

[0063] Based on the dynamic model of the launch vehicle in the upright state, the state space of the attitude control system of the rocket in the upright state is constructed;

[0064] The state space of the attitude control system of the vertical rocket is transformed by pull-type, and the open-loop transfer functions of the pitch channel, yaw channel and roll channel of the attitude control system of the vertical rocket are obtained;

[0065] The open-loop transfer functions of the pitch channel, yaw channel and roll channel of the upright rocket attitude control are plotted into open-loop rocket body characteristic Bode diagrams. Based on the open-loop rocket body characteristic Bode diagrams, the pitch channel de-bouncing network, yaw channel de-bouncing network and roll channel de-bouncing network are designed to make the attitude control system meet the margin index requirements.

[0066] Step 1: Establish the dynamic model of the launch vehicle in the upright state

[0067] The dynamic model of the launch vehicle in the upright state is:

[0068]

[0069] in:

[0070] q i represents the i-th order generalized displacement of the arrow body, i = 1, 2, ..., n, n represents the total order of the mode;

[0071] represents the i-th order generalized velocity of the arrow body;

[0072] represents the i-th order generalized acceleration of the arrow body;

[0073] ω i represents the i-th order elastic circular frequency of the arrow body;

[0074] ξ i represents the i-th order elastic damping ratio of the rocket body;

[0075] D″ ψ_3i , D″ γ_3i They represent the i-th order elastic generalized force coefficients corresponding to the inertial forces of the engine nozzle swing in the pitch, yaw and roll channels respectively;

[0076] R zi (x GZ ), R zi (x ST ) represent the i-th order elastic rotation angle in the Z direction at the inertial group and the rate gyro respectively;

[0077] R yi (x GZ ), R yi (x ST ) represent the i-th order elastic rotation angle in the Y direction at the inertial group and the rate gyro respectively;

[0078] R yi (x GZ ), R yi (x ST ) represent the i-th order elastic rotation angle in the X direction at the inertial group and the rate gyro respectively;

[0079] Respectively represent the angular velocity measured in the Z direction by the inertial group and the rate gyro;

[0080] They represent the angular velocity measured in the Y direction by the inertial group and the rate gyro respectively;

[0081] They represent the angular velocity measured in the X direction by the inertial group and the rate gyro respectively;

[0082] They represent the equivalent angular acceleration of the pitch, yaw and roll channel engine nozzle respectively.

[0083] Step 2: Construct the state space of the attitude control system of the upright rocket based on the dynamic model. The dynamic model of the upright launch vehicle is further written into the state space form.

[0084]

[0085] in, is the rocket state vector, including the generalized displacement and generalized velocity of the elastic mode of the rocket body;

[0086] A=diag(A i ),

[0087] diag() is a diagonal matrix function

[0088]

[0089] C=[C 1 C 2 … C n ],

[0090] When the above state space represents the pitch channel, λ=1,κ=z, When the state space represents the yaw channel, λ=2, κ=y, η=ψ; when the state space represents the roll channel, λ=1, κ=x, η=γ; i=1, 2,…,n, where n represents the total modal order.

[0091] Step 3: Design a three-channel open-loop transfer function

[0092] The calculation formula of the open-loop transfer function of the pitch, yaw, and roll channels is as follows:

[0093]

[0094] Where s represents the complex frequency of the Lassen transformation, κ = z, represents the pitch channel, κ=y, η=ψ represents the yaw channel, κ=x, η=γ represents the roll channel;

[0095] s represents the complex frequency of the Laplacian transformation;

[0096] They represent the open-loop transfer functions of the pitch, yaw, and roll channels, respectively;

[0097] They represent the transfer functions of the pitch, yaw, and roll channel servo equivalent swing angles obtained from the state space to the attitude angular rate at the inertial group; They represent the transfer functions of the pitch, yaw, and roll channel servo equivalent swing angles obtained from the state space to the attitude angular rate at the rate gyro;

[0098] Respectively represent the static amplification factors of pitch, yaw and roll attitude angle channels;

[0099] Respectively represent the dynamic amplification factors of pitch, yaw and roll attitude angular rate channels;

[0100] W GZ (s), W ST (s) represent the transfer functions of the inertial group and rate gyro, respectively;

[0101] W sf (s) represents the servo transfer function;

[0102] Step 4: Design a three-channel debounce network

[0103] (1) System margin meets index requirements

[0104] In the step (3), a characteristic diagram of the arrow body is drawn based on the three-channel transfer function, and a debouncing network is designed so that the system margin meets the index requirements:

[0105]

[0106] in, W jzψ (s), W jzγ (s) represent the debounce networks designed for pitch, yaw, and roll channels respectively; L zb Indicates the amplitude margin index. zb Should be less than or equal to -6dB.

[0107] (2) De-jittering network

[0108] like Figure 2As shown, the pitch channel de-jitter network, the yaw channel de-jitter network and the roll channel de-jitter network respectively perform low-pass filtering on the control quantities obtained by the PD control method of the pitch channel, yaw channel and roll channel of the attitude control system (attenuating the elastic vibration signal of the upright state launch vehicle), output the pitch, yaw and roll channel control swing angles, perform servo swing angle allocation matrix operation on the pitch, yaw and roll channel control swing angles and output them to the servo controller, and the servo controller outputs servo control instructions to the servo mechanism to control the swing of the engine nozzle, thereby controlling the attitude of the upright state rocket.

[0109] The pitch channel de-jitter network, yaw channel de-jitter network and roll channel de-jitter network are composed of multiple second-order link filters. The number of second-order link filters can be selected according to the size and number of the elastic peak of the specific rocket body characteristics, and try to be consistent with the number of second-order link filters of the flight correction network after takeoff, so as to ensure that there is no overshoot when the network is switched before or at the moment of takeoff. The pitch channel de-jitter network, yaw channel de-jitter network and roll channel de-jitter network are in the following form:

[0110]

[0111] Among them, Ω j is the pole second-order link circular frequency, ζ j is the damping ratio of the second-order link at the pole, Ω' k is the zero-point second-order link circular frequency, ζ' k is the damping ratio of the zero-point second-order link, and M and K are both integers.

[0112] In a specific embodiment of the present invention:

[0113]

[0114] in, Mainly suppress low-frequency elastic vibration, Main mid-frequency elastic vibration, The main high-frequency elastic vibration, the overall low-frequency phase of W(s) should not lag too seriously, and the step response should not be too different from the first set of networks after takeoff to prevent overshoot during network switching, which will cause the servo swing angle command to be uneven.

[0115] Example:

[0116] The embodiment of the present invention utilizes the designed anti-jitter network parameters and dynamic model, and adopts Figure 1 The simulation verification flow chart of the attitude control system of the launch vehicle in the upright state is shown to complete the time domain simulation verification. In the simulation, the attitude angular velocity rate deviation is superimposed and injected to verify the anti-interference ability of the system after being impacted by the outside world. Figure 3 to Figure 6 This is a comparison chart of the self-oscillation suppression effect before and after the de-jitter network is adopted.

[0117] The simulation results show that after adopting the debouncing network, the elastic vibration signals in the angular rate deviation signal and the servo swing angle command signal are effectively curbed and attenuated. This design method can effectively suppress the self-excited oscillation of the rocket body and make the attitude control system have strong anti-interference ability.

[0118] Although the present invention has been disclosed as above in the form of a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art may make possible changes and modifications to the technical solution of the present invention by using the methods and technical contents disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the protection scope of the technical solution of the present invention.

Claims

1. A method for designing a self-excited oscillation suppression network for a launch vehicle in an upright state, characterized in that These include: According to the constraints and stress state of the rocket in the erected state, the dynamic model of the launch vehicle in the erected state is established; Based on the dynamic model of the launch vehicle in the upright state, the state space of the attitude control system of the rocket in the upright state is constructed; The state space of the attitude control system of the vertical rocket is transformed by pull-type, and the open-loop transfer functions of the pitch channel, yaw channel and roll channel of the attitude control system of the vertical rocket are obtained; The open-loop transfer functions of the pitch channel, yaw channel and roll channel of the upright rocket attitude control are plotted into open-loop rocket body characteristic Bode diagrams. Based on the open-loop rocket body characteristic Bode diagrams, the pitch channel de-bouncing network, yaw channel de-bouncing network and roll channel de-bouncing network are designed to make the attitude control system meet the margin index requirements.

2. The method for designing a self-excited oscillation suppression network for a launch vehicle in an upright state according to claim 1, characterized in that: The pitch channel de-jitter network, the yaw channel de-jitter network and the roll channel de-jitter network respectively perform low-pass filtering on the control quantities obtained by the PD control method of the pitch channel, yaw channel and roll channel of the attitude control system, and output the pitch, yaw and roll channel control swing angles.

3. The method for designing a self-excited oscillation suppression network for a launch vehicle in an upright state according to claim 2, characterized in that: The transfer functions of the pitch channel de-shaking network, the yaw channel de-shaking network and the roll channel de-shaking network are composed of a plurality of second-order link filters and are in the following form: Among them, Ω j is the pole second-order link circular frequency, ζ j is the damping ratio of the second-order link at the pole, Ω' k is the zero-point second-order link circular frequency, ζ′ k is the damping ratio of the zero-point second-order link, and M and K are both integers.

4. The method for designing a self-excited oscillation suppression network for a launch vehicle in an upright state according to claim 1, characterized in that: The dynamic model of the launch vehicle in the upright state is: in: q i represents the i-th order generalized displacement of the arrow body, i = 1, 2, ..., n, n represents the total order of the mode; represents the i-th order generalized velocity of the arrow body; represents the i-th order generalized acceleration of the arrow body; ω i represents the i-th order elastic circular frequency of the arrow body; ξ i represents the i-th order elastic damping ratio of the rocket body; D ψ ″ _3i , D γ ″ _3i They represent the i-th order elastic generalized force coefficients corresponding to the inertial forces of the engine nozzle swing in the pitch, yaw and roll channels respectively; R zi (x GZ ), R zi (x ST ) represent the i-th order elastic rotation angle in the Z direction at the inertial group and the rate gyro respectively; R yi (x GZ ), R yi (x ST ) represent the i-th order elastic rotation angle in the Y direction at the inertial group and the rate gyro respectively; R yi (x GZ ), R yi (x ST ) represent the i-th order elastic rotation angle in the X direction at the inertial group and the rate gyro respectively; Respectively represent the angular velocity measured in the Z direction by the inertial group and the rate gyro; They represent the angular velocity measured in the Y direction by the inertial group and the rate gyro respectively; They represent the angular velocity measured in the X direction by the inertial group and the rate gyro respectively; They represent the equivalent angular acceleration of the pitch, yaw and roll channel engine nozzle respectively.

5. The method for designing a self-excited oscillation suppression network for a launch vehicle in an upright state according to claim 4, characterized in that: The state space of the upright posture control system is: in, is the rocket state vector, including the generalized displacement and generalized velocity of the elastic mode of the rocket body; A=diag(A i ), diag() is a diagonal matrix function; C=[C1 C2 … C n ], κ=z, represents the pitch channel, κ=y, η=ψ represents the yaw channel, κ=x, η=γ represents the roll channel, λ is the coefficient defined by the output matrix C that distinguishes the three channels. For the pitch channel and the roll channel, λ=1, and for the yaw channel, λ=2.

6. The method for designing a self-excited oscillation suppression network for a launch vehicle in an upright state according to claim 1, characterized in that: The calculation formula of the open-loop transfer function of the pitch, yaw, and roll channels is as follows: Where s represents the complex frequency of the Lassen transformation, κ = z, represents the pitch channel, κ=y, η=ψ represents the yaw channel, κ=x, η=γ represents the roll channel, and E is the unit matrix; They represent the transfer functions of the pitch, yaw, and roll channel servo equivalent swing angles obtained from the state space to the attitude angular rate at the inertial group; They represent the transfer functions of the pitch, yaw, and roll channel servo equivalent swing angles obtained from the state space to the attitude angular rate at the rate gyro; Respectively represent the static amplification factors of pitch, yaw and roll attitude angle channels; Respectively represent the dynamic amplification factors of pitch, yaw and roll attitude angular rate channels; W GZ (s), W ST (s) represent the transfer functions of the inertial group and rate gyro, respectively; W sf (s) represents the servo transfer function.

7. The method for designing a self-excited oscillation suppression network for a launch vehicle in an upright state according to claim 1, characterized in that: The pitch, yaw, and roll channel debounce networks meet the following conditions: in, W jzψ (s), W jzγ (s) are the transfer functions of the pitch, yaw, and roll channel debounce networks, respectively; L zb Represents the amplitude margin index, are the open-loop transfer functions of the pitch, yaw, and roll channels, respectively.

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