Time sequence calibration device of rocket engine control system

Abstract

The invention provides a time sequence calibration device for a rocket engine control system, and belongs to the field of liquid rocket engine tests, a first input end of a data acquisition module is in signal connection with an output end of the rocket engine control system, and the data acquisition module is used for acquiring time sequence data of a specific time interval sent by the control system; the rubidium atomic clock is used for sending pulse signals; the input end of the Timing board card is in signal connection with the output end of the rubidium atomic clock, and the Timing board card is used for receiving the pulse signal and performing clock locking on the received pulse signal; a second input end of the data acquisition module is in signal connection with an output end of the Timing board card, and the data acquisition module is used for receiving the pulse signal after clock locking and taking the pulse signal after clock locking as a rubidium atomic clock time sequence reference; the input end of the calibration module is in signal connection with the output end of the data acquisition module, and the calibration module is used for calibrating time sequence data of a specific time interval according to the rubidium atomic clock time sequence reference.

Description

Technical Field

[0001] The present invention belongs to the field of liquid rocket engine tests, and particularly relates to a timing calibration device for a rocket engine control system. Background Art

[0002] During the test process of a liquid rocket engine, the engine test control system is mainly responsible for controlling the actions of the engine to make it work according to a pre-specified program to verify the performance of the engine. The control system timing is mainly used to control the test time length of the engine, the valve action time length, etc., and the accuracy of the action time length directly affects the overall process state of the engine test. For example, if the designed action time length of a certain valve is 100 s and the actual action time length is 101 s, it will cause an increase in the consumption of a certain propellant by about 300 kg, directly affecting the payload during flight. Therefore, it is particularly important to study the calibration method of the control system timing and obtain the actual time length of the control system timing.

[0003] Currently, in the liquid power and other related industries, the control system usually conducts calibration work by calibrating its internal crystal oscillator. The output frequency of its internal crystal oscillator is generally greater than 10 MHz, and the accuracy is generally 10 -5 ~10 -6 , because the output frequency of the crystal oscillator is relatively high, and it is usually used after frequency division under test conditions and requires operations such as switching, the generated timing has a large difference from the frequency generated by the crystal oscillator. Under this calibration method, it fails to be well consistent with the test state and has a large difference from the time parameters used in actual engineering; in addition, the timing sent by the control system is controlled not only by the crystal oscillator element but also by various types of elements such as MOS transistors and relays, and the specific delay ranges from 10 ms to 100 ms according to the circuit design and case type, and the specific delay time cannot be theoretically calculated.

[0004] Therefore, the existing calibration method of the crystal oscillator cannot obtain the accurate duration of a certain timing, and the calibration accuracy is relatively low, which cannot meet the timing calibration requirements of liquid rocket engine tests. Summary of the Invention

[0005] In order to overcome the deficiencies of the above-mentioned existing technologies, the present invention provides a timing calibration device for a rocket engine control system, including: A data acquisition module, whose first input end is signal-connected to the output end of the rocket engine control system, and is used to acquire the timing data of a specific time interval sent by the control system; A rubidium atomic clock, which is used to send pulse signals; The Timing board card, whose input end is signal-connected to the output end of the rubidium atomic clock, is used to receive pulse signals and perform clock locking on the received pulse signals; the second input end of the data acquisition module is signal-connected to the output end of the Timing board card, and the data acquisition module is used to receive the pulse signals after clock locking and use the pulse signals after clock locking as the timing reference of the rubidium atomic clock; The calibration module, whose input end is signal-connected to the output end of the data acquisition module, is used to calibrate the timing data of a specific time interval according to the timing reference of the rubidium atomic clock.

[0006] Preferably, the calibration of the timing data of a specific time interval according to the timing reference of the rubidium atomic clock is specifically calculated by the following formula: T 实际 =T + T1 - T0; In the formula, T1 is the timing length of the timing data sent by the control system, T0 is the timing length of the timing data collected by the data acquisition module, T is the timing length of the pulse signal after clock locking sent by the rubidium atomic clock, and T 实际 is the timing length of the calibrated timing data.

[0007] Preferably, the frequency accuracy of the rubidium atomic clock is 10 -11 .

[0008] Preferably, the output signal of the rubidium atomic clock is a 1s pulse signal.

[0009] Preferably, the Timing board card is a board card of model Timing-V3.

[0010] Preferably, the Timing board card is signal-connected to the 1PPS output end of the rubidium atomic clock.

[0011] Preferably, the data acquisition module is a 1820 board card of DEWETRON.

[0012] Preferably, the timing lengths sent by the control system are 100s, 600s, and 1000s.

[0013] The rocket engine control system timing calibration device provided by the present invention has the following beneficial effects: By signal-connecting the output end of the rubidium atomic clock to the input end of the Timing board card, the present invention can perform clock locking on the pulse signals of the rubidium atomic clock; by signal-connecting the second input end of the data acquisition module to the output end of the Timing board card, the present invention can switch the timing reference of the control system, thereby disconnecting the original sampling reference and calibrating the control system timing data with the timing reference of the rubidium atomic clock after clock locking, so as to improve the accuracy of timing calibration. Description of the Drawings

[0014] To more clearly illustrate the embodiments of the present invention and their design solutions, the accompanying drawings required for this embodiment will be briefly introduced below. The accompanying drawings in the following description are only partial embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other accompanying drawings can be obtained based on these drawings.

[0015] Figure 1 It is the overall structure diagram of the timing calibration device for the rocket engine control system according to the embodiment of the present invention; Figure 2 It is the output waveform diagram of the rubidium atomic clock 1PPS; Figure 3 They are the errors under different time lengths. Specific Embodiments

[0016] In order to enable those skilled in the art to better understand the technical solutions of the present invention and implement them, the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention and cannot be used to limit the protection scope of the present invention.

[0017] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "axial", "radial", "circumferential", etc. is based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of describing the technical solutions of the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to the present invention.

[0018] In addition, terms such as "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. In the description of the present invention, it should be noted that unless otherwise clearly specified or limited, the terms "connected" and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. In the description of the present invention, unless otherwise stated, the meaning of "plurality" is two or more, which will not be elaborated here.

[0019] Embodiment The present invention provides a timing calibration device for a rocket engine control system, specifically as Figure 1As shown, it includes a data acquisition module, a rubidium atomic clock, a timing board and a calibration module. The first input end of the data acquisition module is connected to the output end signal of the rocket engine control system, and the data acquisition module is used to acquire the timing data of a specific time interval sent by the control system; the rubidium atomic clock is used to send a pulse signal; the input end of the timing board is connected to the output end signal of the rubidium atomic clock, and is used to receive the pulse signal and clock-lock the received pulse signal; the second input end of the data acquisition module is connected to the output end signal of the timing board, and the data acquisition module is used to receive the pulse signal after the clock is locked, and use the pulse signal after the clock is locked as the timing reference of the rubidium atomic clock; the input end of the calibration module is connected to the output end signal of the data acquisition module, and is used to calibrate the timing data of a specific time interval according to the timing reference of the rubidium atomic clock, and the output end of the calibration module is connected to the actuator of the rocket engine, such as a valve.

[0020] The present invention calibrates the time series data specifically through the following formula: T 实际 =T+T1-T0; In the formula, T1 is the time sequence length of the time sequence data sent by the control system, T0 is the time sequence length of the time sequence data collected by the data acquisition module, T is the time sequence length of the pulse signal sent by the rubidium atomic clock after clock locking, and T 实际 is the time series length of the calibrated time series data.

[0021] The structure of the control system timing calibration device of the present invention is shown in Table 1.

[0022] Table 1 Composition of control system timing calibration device

[0023] In this embodiment, the control system sends the timing data of a specific time interval to the data acquisition module (such as a 100s waveform). The data acquisition module selects the DEWETRON 1820 board to collect the waveform of the timing data sent by the control system, and compares the collected time with the control system sending time to obtain the control system timing error. However, since the initial state of the internal time base of the control system is the internal clock, the accuracy of the internal clock is 10 -5 , which is basically the same order of magnitude as the data acquisition module. Therefore, the use of the built-in internal time base as the standard cannot meet the comparison requirements. The present invention connects the rubidium atomic clock to the input signal of the timing board, which can increase the accuracy of the internal clock of the control system to 10 -5 The reference is switched to a frequency accuracy of 10 -11 An external rubidium atomic clock timing reference is used to effectively improve the sampling accuracy.

[0024] In the present invention, for the externally connected rubidium atomic clock, its output interfaces include 1MH, 5MHz, 10MHz, 1PPS and other interfaces. According to the system matching situation, the present invention selects 1PPS as the frequency standard output of the rubidium atomic clock, that is, the "1PPS" output interface of the rubidium atomic clock is signal-connected to the PPS input interface in the Timing board. The output signal of the rubidium atomic clock is a 1s pulse signal, and its signal waveform is as Figure 2 shown. This signal can be recognized by the Timing board and the received pulse signal is clock-locked through the converter chain. After the clock locking is completed, the data acquisition module will use the pulse signal after clock locking as the timing reference and display the absolute time as the acquisition time axis.

[0025] In this embodiment, an external antenna is connected to the rubidium atomic clock for satellite searching. After locking to Beidou, the calibration accuracy can be further improved.

[0026] Combined with the timing design duration of the current engine test process control system and the application status of such systems at home and abroad, when designing the timing calibration duration of the control system, the maximum duration is designed to be 2000s. Designed according to this principle, there are three test points for the timing calibration duration of the control system, namely 100s, 600s, and 1000s, as Figure 3 shown.

[0027] In order to verify the feasibility of the time base conditioning technology and the calibration duration design and ensure that the system performance meets the requirements, 33511B is used as the input signal. 33511B is a model of a signal source used to simulate the timing issued by the control system. 100s of data is collected using the internal time base and the rubidium atomic time base respectively and calibrated. The results are shown in Table 2, where the time base is the abbreviation of the timing reference.

[0028] The results show that when using the internal time base of the system, the error is 0.191ms at a time length of 100s, and when using the rubidium atomic clock time base, the error is -0.038ms.

[0029] Under the same input state, when the time length is changed to 600s, the acquisition results are shown in Table 3. The results show that when using the internal time base of the system, the error is 0.938ms at a time length of 600s, and when using the rubidium atomic clock time base, the error is -0.238ms.

[0030] Table 2 Time length verification 1

[0031] Under the same input state, when the time length is changed to 1000 s, the acquisition results are shown in Table 4. The results show that when using the internal time base of the system, at a time length of 1000 s, the error is 1.573 ms, and when using the rubidium atomic clock time base, the error is -0.346 ms. The results show that by the method of externally connecting a rubidium atomic time base to replace the original internal time base of the control system, the measurement accuracy can be effectively improved, and as the measured time length increases, the gap between the two will be more significant.

[0032] Table 3 Time length verification 2

[0033] Table 4 Time length verification 3

[0034] To sum up, through the device of the present invention, the measurement accuracy can be significantly improved, and the improvement degree is about 1.2%.

[0035] According to the requirements in the self-compiled specification "Control System Timing Calibration Specification", the main calibration items of the control system timing are accuracy, rise time, and fall time. Calibration device frequency measurement range: ≤2 kHz; Timing measurement range: ≤2000 s; Timing measurement accuracy: better than 0.1 ms (@100 s). The present invention can carry out calibration work on a control system with an output amplitude of 0 - 30 V and meeting the above frequency and timing requirements.

[0036] A rocket engine control system timing calibration device designed by the present invention conducts item calibration in sequence according to the requirements of the "Control System Timing Calibration Specification", and performs data processing and calculation after data acquisition by the data acquisition module (the specific method is omitted).

[0037] To test the performance and operating status of the rocket engine control system timing calibration device of the present invention, control system timing calibration work was carried out at 2 stations in a certain test area, and the calibration results were compared with those of the traditional calibration method. The results show that after using this calibration device, Station 1 has been improved from being unable to be calibrated due to no interface originally to being able to be calibrated, and the calibration result is 0.00051% (@1000 s), and the calibration result of Station 2 is 0.00038% (@1000 s), both meeting the requirements of the test task for the control system.

[0038] The above-described embodiments are only preferred specific embodiments of the present invention, and the protection scope of the present invention is not limited thereto. Any simple changes or equivalent replacements of the technical solutions that can be obviously obtained by those skilled in the art within the technical scope disclosed by the present invention all belong to the protection scope of the present invention.

Claims

1. A timing calibration device for a rocket engine control system, characterized in that, Including: A data acquisition module, whose first input end is signal-connected to the output end of the rocket engine control system, and is used to acquire the timing data of a specific time interval sent by the control system; A rubidium atomic clock, which is used to send pulse signals; A Timing board card, whose input end is signal-connected to the output end of the rubidium atomic clock, and is used to receive the pulse signal and perform clock locking on the received pulse signal; the second input end of the data acquisition module is signal-connected to the output end of the Timing board card, and the data acquisition module is also used to receive the pulse signal after clock locking and use the pulse signal after clock locking as the rubidium atomic clock timing reference; A calibration module, whose input end is signal-connected to the output end of the data acquisition module, and is used to calibrate the timing data of a specific time interval according to the rubidium atomic clock timing reference.

2. The timing calibration device for a rocket engine control system according to claim 1, characterized in that, The calibration of the timing data of a specific time interval according to the rubidium atomic clock timing reference is specifically calculated by the following formula: T 实际 = T + T1 - T0; Wherein, T1 is the timing length of the timing data sent by the control system, T0 is the timing length of the timing data collected by the data acquisition module, T is the timing length of the pulse signal after clock locking sent by the rubidium atomic clock, and T 实际 is the timing length of the calibrated timing data.

3. The timing calibration device for a rocket engine control system according to claim 1, characterized in that, The frequency accuracy of the rubidium atomic clock is 10 -11 .

4. The timing calibration device for a rocket engine control system according to claim 1, wherein The output signal of the rubidium atomic clock is a 1s pulse signal.

5. The timing calibration device for a rocket engine control system according to claim 1, wherein The Timing board card is a board card of model Timing-V3.

6. The timing calibration device for a rocket engine control system according to claim 1, characterized in that The Timing board card is signal-connected to the 1PPS output end of the rubidium atomic clock.

7. The timing calibration device for a rocket engine control system according to claim 1, characterized in that, The data acquisition module is a 1820 board card of DEWETRON.

8. The timing calibration device for a rocket engine control system according to claim 2, characterized in that, The timing lengths sent by the control system are 100s, 600s, and 1000s.

Images