A highly reliable parachute control method for ballistic entry spacecraft

Abstract

This invention discloses a highly reliable parachute deployment control method for ballistic reentry spacecraft. During the 0g overload period before reentry, software collects and filters information from overload sensors in each channel to obtain the overload zero-point value, which is then stored in a register. When the zero-point output voltage of the overload sensor exceeds the normal range of zero-point drift, external power-on is prompted to restore the fault. This method solves the problem of overload sensor circuit failure due to single-event effects before reentry. During the operation of the recovery control system, the difference between the measured overload value and the zero-point value is used for judgment. Utilizing the characteristic that the sensitivity of the overload sensor does not change over time, the influence of zero drift of the overload sensor on the parachute deployment timing accuracy is eliminated when the probe mission is long. This invention employs a multi-mode combined control method, combining overload time-based parachute deployment control and pure time-based parachute deployment control methods.

Description

Technical Field

[0001] This invention relates to a highly reliable parachute deployment control method for ballistic entry spacecraft, belonging to the field of intelligent control technology. Background Technology

[0002] "Entry" generally refers to both atmospheric reentry and deceleration from an extraterrestrial body and return to Earth. The term "return" will be used as a shorthand to represent both missions. The return and landing of a recoverable spacecraft generally refers to the process from entering the atmosphere from the outer space side, crossing the Kármán line (at an altitude of 100 km), until landing. During this process, the spacecraft encounters a complex and variable environment, making accurate parachute deployment for deceleration and cushioning crucial. Early deployment can cause the parachute to be damaged due to high dynamic pressure, while late deployment results in insufficient deceleration time and excessive landing velocity. Both situations degrade the deceleration and landing cushioning performance of the spacecraft's recovery system. Deep space exploration spacecraft mostly use ballistic reentry, typically requiring overload-time control for parachute deployment. Traditional recoverable satellites use mechanical accelerometer switches to measure ballistic acceleration. These switches weigh approximately 150g each, have slightly lower manufacturability, and a lower yield rate, failing to meet miniaturization requirements. The patent "A Lightweight and Highly Reliable Control System and Method for Small Object Probe Return" (202218007998.3, inventors: Sun Xiyun et al.) relates to a lightweight and highly reliable control system and method for small object probe return. It adopts a dual-machine four-mode software architecture to ensure the reliability of the control system. Through the optimal overload-time feature point selection method, it performs data analysis on n return trajectory overload curves and gives the optimal overload discrimination feature points for the ascent and descent segments based on dynamic pressure. The overload-time main backup parachute opening control method is designed. The overload information is detected by a filtered sliding window, and the main backup parachute opening point is found according to the feature points selected by the optimal overload-time feature point selection method. The method has the following defects: (1) When the probe mission is long, such as a small object probe mission of 2 to 3 years, the zero position of the overload sensor will drift. Using a fixed threshold to determine the overload parachute opening trigger point will result in parachute control timing accuracy deviation; (2) When two of the three overload sensors fail due to a certain common cause of aging, it will cause a failure mode of overload judgment failure. To solve the above problems, it is necessary to improve the control system and control method of the patent "A lightweight and highly reliable control system and method for small celestial body exploration and return".

[0003] Existing problems:

[0004] When the exploration mission is long, such as a small celestial body exploration mission lasting 2-3 years, the zero point of the overload sensor will drift. Using a fixed threshold to determine the overload parachute deployment trigger point will result in deviations in parachute control timing accuracy. By collecting and processing information from each overload sensor during the 0g overload period before reentry, the software obtains the overload zero point value and stores it in a register. During the operation of the recovery control system, the measured overload value is compared with the zero point for judgment. By utilizing the characteristic that the sensitivity of the overload sensor does not change over time, the influence of overload zero drift on the parachute deployment trigger timing accuracy is eliminated.

[0005] Although the overload sensor can form a 3-out-of-2 redundancy mode and the A / D conversion circuit can form a parallel redundancy mode, when the overload sensor output is too low or the A / D conversion circuit is open or short-circuited, the recovery controller will not be able to read the re-entry overload signal, and the subsystem will not be able to automatically execute the parachute opening procedure. In order to deal with the above hardware failures and improve the reliability of the recovery parachute opening command, a multi-mode control strategy combining overload time parachute opening control and pure time parachute opening control methods is adopted.

[0006] In-orbit overload zero drift elimination is mostly applied in the field of space exploration, represented by small celestial body exploration. No relevant information was found on the overload zero drift elimination method during the reentry process. Summary of the Invention

[0007] The technical problem solved by this invention is to overcome the shortcomings of the prior art and provide a highly reliable parachute deployment control method for ballistic entry spacecraft, which solves the problem of parachute failure due to multiple sensor malfunctions caused by common cause failure.

[0008] The technical solution of this invention is:

[0009] This invention discloses a highly reliable parachute deployment control method for ballistic entry spacecraft, comprising the following steps:

[0010] S1. Determine the time parameters Ta to Th and the corresponding T1 to T8 registers corresponding to the overload target point;

[0011] S2, the recycling control program is powered on;

[0012] S3. Perform overload zero-position calibration;

[0013] S4. When an external input command is received, start the timing of registers T1 and T2. When the time in register T1 reaches the threshold Ta, proceed to step S11; when the time in register T2 reaches the threshold Tb, proceed to step S5.

[0014] S5. Detect overload target point a. If the time in register T1 reaches time Ta, proceed to step S11. If overload target point a is detected and the time in register T1 has not reached time Ta, proceed to step S6. Otherwise, repeat step S5.

[0015] S6. Start timing in registers T3 and T4, and simultaneously determine if the time in register T1 has reached time Ta. If so, proceed to step S11. When the time in register T3 reaches time Tc, proceed to step S10. When the time in register T4 reaches time Td, proceed to step S7.

[0016] S7. Detect the overload target point b and determine whether the time in register T1 has reached time Ta. If yes, proceed to step S11. If the time in register T3 reaches time Tc and the overload descent target point b is detected, proceed to step S8. If the time in register T3 has not reached time Tc and the overload descent target point b is detected, proceed to step S8. If the time in register T3 reaches time Tc and the overload descent target point b is not detected, proceed to step S10. Otherwise, repeat step S7.

[0017] S8. Start the timer in register T5 and determine if the time in register T1 has reached time Ta. If so, proceed to step S11. When the time in register T3 reaches time Tc, proceed to step S10. When the time in register T5 reaches the threshold Te, proceed to step S9.

[0018] S9. Send the parachute release command, and send the parachute disengagement command after a delay of Tf through the T6 register;

[0019] S10, Send the parachute release command, and send the parachute disengagement command after a delay of Tg through the T7 register;

[0020] S11. Send the parachute launch command, and send the parachute disengagement command after a delay of Th through the T8 register.

[0021] Furthermore, in the above control method, determining the time parameter and the corresponding timing register corresponding to the overload target point specifically involves:

[0022] The time parameter corresponding to the overload target point is:

[0023] Ta: Time parameters for pure time-based parachute opening mode;

[0024] Tb: Protection time parameter to prevent overload detection from interfering with the separation of the return capsule from the main detector;

[0025] Tc: The time parameter for the backup parachute deployment mode, with target point a in the overload ascent phase as the backup parachute deployment mode;

[0026] Td: The time parameter from the overload target point a to the overload peak value;

[0027] Te: Time parameters for parachute deployment mode with target point b during overload descent as the primary component;

[0028] Tf: Overload + Delay main parachute opening mode deceleration parachute working time parameter;

[0029] Tg: Overload + Delayed Backup Parachute Opening Mode Deceleration Parachute Working Time Parameter;

[0030] Th: Parachute operating time parameters in pure time-backup deployment mode.

[0031] The above time is fixed as a parameter in the recycling control program parameter list, and the T1~T8 registers are used for timing.

[0032] T1: Pure time umbrella opening mode timing register;

[0033] T2: Protection timer register to prevent overload detection from interfering with separation of the return capsule from the main detector;

[0034] T3: Timer register for backup parachute opening mode with target point a of the overload ascent phase as the backup parachute opening mode;

[0035] T4: Timing register for the time from overload target point a to overload peak value;

[0036] T5: Timer register for parachute opening mode with overload descent target point b as the main component;

[0037] T6: Overload + Delay Main Parachute Opening Mode Deceleration Parachute Working Time Timing Register;

[0038] T7: Overload + Delayed Backup Parachute Opening Mode Deceleration Parachute Working Time Timing Register;

[0039] T8: Time-based backup parachute opening mode deceleration parachute working time timing register.

[0040] Furthermore, in the above control method, the overload zero-position calibration specifically involves:

[0041] Calculate the range of the zero-point output voltage value of the overload sensor;

[0042] Determine if the zero-point output voltage value of the overload sensor is out of range. If so, prompt external measures to be taken to restore the fault.

[0043] Furthermore, in the above control method, the range of the zero-point output voltage value of the overload sensor is specifically as follows:

[0044] [(Ref / 2-Vd)×Sens×(2 n -1) / Ref,(Ref / 2+Vu)×Sens×(2 n -1) / Ref]

[0045] Where Ref / 2 is the theoretical overload zero-point voltage value, Vd is the maximum lower deviation of the overload sensor zero-point drift, Vu is the maximum upper deviation of the overload sensor zero-point drift, Sens is the overload sensor sensitivity, and n is the digital effective bit.

[0046] Furthermore, in the above control method, the detection of the overload target point a is specifically performed as follows:

[0047] When GZ_value_fit≥F1, the count value of the corresponding channel's cumulative register is incremented;

[0048] When GZ_value_fit < F1, the count value of the corresponding channel's cumulative register is cleared to zero.

[0049] Where, F1 = Ga × Sens × (2 n -1) / Ref; F1 is the digital threshold of target point a relative to zero, GZ_value_fit is the filtered overload digital value, Ga is the overload value of target point a in the overload rising segment, Sens is the overload sensor sensitivity, Ref is the AD chip reference voltage, and n is the digital valid bits;

[0050] When the cumulative register count value meets the time requirement, the overload target point a of the rising segment is successfully detected.

[0051] Furthermore, in the above control method, the detection of the overload target point b specifically includes:

[0052] When GZ_value_fit≤F2, the count value of the corresponding channel's cumulative register is incremented;

[0053] When GZ_value_fit > F2, the count value of the corresponding channel's cumulative register is cleared to zero;

[0054] Where F2 = Gb × Sens × (2 n -1) / Ref; F2 is the digital threshold of target point b relative to zero; GZ_value_fit is the filtered overload digital value, Gb is the overload value of target point b in the overload descent segment, Sens is the overload sensor sensitivity, Sens is the overload sensor sensitivity, Ref is the AD chip reference voltage, and n is the digital valid bits.

[0055] When the cumulative register count value meets the time requirement, the overload descent segment target point b is successfully detected.

[0056] Furthermore, in the above control methods,

[0057] If GZ_value_fit>GZ_zero, GZ_value_fit=GZ_value_fit-GZ_zero;

[0058] If GZ_value_fit≤GZ_zero, GZ_value_fit=0;

[0059] Where GZ_value_fit is the filtered overload digital value; GZ_zero is the overload zero value.

[0060] Furthermore, in the above control methods,

[0061] Tb+TTA+Tc>Tb+TTB+Te,Ta>Tb+TTA+Tc+Tg

[0062] Where TTA is the time when overload target point a is detected; TTB is the time when overload target point b is detected.

[0063] The advantages of this invention over the prior art are as follows:

[0064] (1) The present invention obtains the overload zero value by software collecting and processing the information of each overload sensor when the rectifier is in the 0g overload period before reentry, and determines whether the zero output voltage value of the overload sensor exceeds the normal range of zero drift. If so, it prompts external measures to be taken and power is restored to recover the fault. This can solve the problem of overload sensor circuit failure due to single event effect before reentry.

[0065] (2) In the operation of the recovery control system, the present invention compares the measured overload value with the zero position to make a judgment. It utilizes the characteristic that the sensitivity of the overload sensor does not change with time, thereby eliminating the influence of the parachute opening trigger timing accuracy deviation caused by overload zero drift. This solves the problem of poor parachute opening control accuracy caused by the long-term zero drift of the capacitive overload sensor when using ballistic return overload delay control parachute.

[0066] (3) The multi-mode combined control method adopted in this invention uses pure time-based umbrella opening control as a backup scheme, which can solve the problem of being unable to open the umbrella when multiple sensors fail due to a common cause failure.

[0067] (4) Based on the reason that the reliability of multi-mode decision is higher than that of reentry time control accuracy, and combined with the optimal result of parachute opening dispersion, this invention designs the "overload + delayed primary parachute opening" time point to precede the "overload + delayed backup parachute opening" time point, and the "overload + delayed backup parachute opening" time point to precede the "pure time backup parachute opening control" time point, thus solving the combined logical relationship of the three parachute opening control modes.

[0068] (5) The present invention sets an input command to start the pure time parachute opening control timer. If the overload sensor fails and cannot detect the overload ascent target point a, the lower limit condition for parachute opening is guaranteed by the pure time backup parachute opening control mode.

[0069] (6) This invention sets an input command to start the pure time parachute opening control timer. If the overload sensor fails and cannot detect the target point b of the overload descent segment, the reliable conditions for parachute opening are ensured by relying on the overload backup parachute opening control.

[0070] (7) The present invention sets up a protection time timing register, which only performs pure time parachute opening timing during the time period and does not judge the overload target point, thus avoiding the overload detection interference caused by the separation of the return capsule and the main detector. This can solve the problem of premature parachute opening caused by the overload of the main and return capsules when using the full curve trend of overload for parachute opening control.

[0071] (8) The present invention sets up a protection time timing register, and uses the ballistic reentry overload curve change trend to detect the rising segment a point after delaying the overload peak value, and then detects the falling segment b point, so as to avoid signal jitter in the overload rising segment and detect the overload falling segment b point in advance, which would lead to premature parachute opening. Attached Figure Description

[0072] Figure 1 This is a schematic diagram illustrating the time relationship of the three parachute opening control modes on the overload-time curve according to the present invention.

[0073] Figure 2 This is a flowchart illustrating the timer design for switching between three umbrella opening control modes in this invention.

[0074] Figure 3 This is a schematic diagram illustrating the process of sampling and processing three-channel overload data using the overload zero-drift elimination technology of this invention. Detailed Implementation

[0075] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0076] This invention discloses a highly reliable parachute deployment control method for ballistic reentry spacecraft. During the 0g overload period before reentry, software collects and filters information from overload sensors across various channels to obtain the overload zero-point value, which is then stored in a register. When the zero-point output voltage of the overload sensor exceeds the normal range of zero-point drift, external power-on is prompted to restore the fault. This method addresses the problem of overload sensor circuit failure due to single-event effects before reentry. During the recovery control system's operation, the difference between the measured overload value and the zero-point value is used for judgment. Utilizing the characteristic that the overload sensor's sensitivity does not change over time, the impact of zero-point drift caused by overload sensor deviation on the parachute deployment timing accuracy is eliminated when the probe mission duration is long. This invention employs a multi-mode combined control method, combining overload-time parachute deployment control and pure-time parachute deployment control. Pure-time parachute deployment control serves as a backup solution, addressing the problem of parachute failure due to multiple sensor malfunctions caused by common-cause failures.

[0077] like Figure 2 As shown, this invention discloses a highly reliable parachute deployment control method for ballistic entry spacecraft, comprising the following steps:

[0078] S1. Determine the time parameters Ta to Th and the corresponding T1 to T8 registers corresponding to the overload target point;

[0079] S2, the recycling control program is powered on;

[0080] S3. Perform overload zero-position calibration;

[0081] S4. When an external input command is received, start the timing of registers T1 and T2. When the time in register T1 reaches the threshold Ta, proceed to step S11; when the time in register T2 reaches the threshold Tb, proceed to step S5.

[0082] S5. Detect overload target point a. If the time in register T1 reaches time Ta, proceed to step S11. If overload target point a is detected and the time in register T1 has not reached time Ta, proceed to step S6. Otherwise, repeat step S5.

[0083] S6. Start timing in registers T3 and T4, and simultaneously determine if the time in register T1 has reached time Ta. If so, proceed to step S11. When the time in register T3 reaches time Tc, proceed to step S10. When the time in register T4 reaches time Td, proceed to step S7.

[0084] S7. Detect the overload target point b and determine whether the time in register T1 has reached time Ta. If yes, proceed to step S11. If the time in register T3 reaches time Tc and the overload descent target point b is detected, proceed to step S8. If the time in register T3 has not reached time Tc and the overload descent target point b is detected, proceed to step S8. If the time in register T3 reaches time Tc and the overload descent target point b is not detected, proceed to step S10. Otherwise, repeat step S7.

[0085] S8. Start the timer in register T5 and determine if the time in register T1 has reached time Ta. If so, proceed to step S11. When the time in register T3 reaches time Tc, proceed to step S10. When the time in register T5 reaches the threshold Te, proceed to step S9.

[0086] S9. Send the parachute release command, and send the parachute disengagement command after a delay of Tf through the T6 register;

[0087] S10, Send the parachute release command, and send the parachute disengagement command after a delay of Tg through the T7 register;

[0088] S11. Send the parachute launch command, and send the parachute disengagement command after a delay of Th through the T8 register.

[0089] Preferably, such as Figure 1 As shown, the time parameters and corresponding timing registers corresponding to the overload target point are determined as follows:

[0090] The time parameter corresponding to the overload target point is:

[0091] Ta: Time parameters for pure time-based parachute opening mode;

[0092] Tb: Protection time parameter to prevent overload detection from interfering with the separation of the return capsule from the main detector;

[0093] Tc: The time parameter for the backup parachute deployment mode, with target point a in the overload ascent phase as the backup parachute deployment mode;

[0094] Td: The time parameter from the overload target point a to the overload peak value;

[0095] Te: Time parameters for parachute deployment mode with target point b during overload descent as the primary component;

[0096] Tf: Overload + Delay main parachute opening mode deceleration parachute working time parameter;

[0097] Tg: Overload + Delayed Backup Parachute Opening Mode Deceleration Parachute Working Time Parameter;

[0098] Th: Parachute operating time parameters in pure time-backup deployment mode.

[0099] The above time is fixed as a parameter in the recycling control program parameter list, and the T1~T8 registers are used for timing.

[0100] T1: Pure time umbrella opening mode timing register;

[0101] T2: Protection timer register to prevent overload detection from interfering with separation of the return capsule from the main detector;

[0102] T3: Timer register for backup parachute opening mode with target point a of the overload ascent phase as the backup parachute opening mode;

[0103] T4: Timing register for the time from overload target point a to overload peak value;

[0104] T5: Timer register for parachute opening mode with overload descent target point b as the main component;

[0105] T6: Overload + Delay Main Parachute Opening Mode Deceleration Parachute Working Time Timing Register;

[0106] T7: Overload + Delayed Backup Parachute Opening Mode Deceleration Parachute Working Time Timing Register;

[0107] T8: Time-based backup parachute opening mode deceleration parachute working time timing register.

[0108] Preferably, overload zero-point calibration is performed, specifically as follows:

[0109] Calculate the range of the zero-point output voltage value of the overload sensor;

[0110] Determine if the zero-point output voltage value of the overload sensor is out of range. If so, prompt external measures to be taken to restore the fault.

[0111] Preferably, the range of the zero-point output voltage value of the overload sensor is as follows:

[0112] [(Ref / 2-Vd)×Sens×(2 n -1) / Ref,(Ref / 2+Vu)×Sens×(2 n -1) / Ref]

[0113] Where Ref / 2 is the theoretical overload zero-point voltage value, Vd is the maximum lower deviation of the overload sensor zero-point drift, Vu is the maximum upper deviation of the overload sensor zero-point drift, Sens is the overload sensor sensitivity, and n is the digital effective bit.

[0114] Preferably, the overload target point a is detected, and the specific method is as follows:

[0115] When GZ_value_fit≥F1, the count value of the corresponding channel's cumulative register is incremented;

[0116] When GZ_value_fit < F1, the count value of the corresponding channel's cumulative register is cleared to zero.

[0117] Where, F1 = Ga × Sens × (2 n -1) / Ref; F1 is the digital threshold of target point a relative to zero, GZ_value_fit is the filtered overload digital value, Ga is the overload value of target point a in the overload rising segment, Sens is the overload sensor sensitivity, Ref is the AD chip reference voltage, and n is the digital valid bits;

[0118] When the cumulative register count meets the time requirement, the overload target point a of the rising segment is successfully detected.

[0119] Preferably, the overload target point b is detected as follows:

[0120] When GZ_value_fit≤F2, the count value of the corresponding channel's cumulative register is incremented;

[0121] When GZ_value_fit > F2, the count value of the corresponding channel's cumulative register is cleared to zero;

[0122] Where F2 = Gb × Sens × (2 n -1) / Ref; F2 is the digital threshold of target point b relative to zero; GZ_value_fit is the filtered overload digital value, Gb is the overload value of target point b in the overload descent segment, Sens is the overload sensor sensitivity, Sens is the overload sensor sensitivity, Ref is the AD chip reference voltage, and n is the digital valid bits.

[0123] When the cumulative register count meets the time requirement, the overload descent segment target point b is successfully detected.

[0124] Preferably,

[0125] If GZ_value_fit>GZ_zero, GZ_value_fit=GZ_value_fit-GZ_zero;

[0126] If GZ_value_fit≤GZ_zero, GZ_value_fit=0;

[0127] Where GZ_value_fit is the filtered overload digital value; GZ_zero is the overload zero value.

[0128] The parachute deployment method can be controlled by combining multiple modes, including "overload + delay primary parachute deployment control," "overload + delay backup parachute deployment control," and "pure time backup parachute deployment control," to ensure that parachute deployment can still be completed even if the overload sensor circuit fails. The program performs redundant decision-making for multi-channel overload signals, resulting in a low probability of multi-channel failure. The pure time deployment mode can guarantee parachute deployment even when multiple overload sensors fail. Once an overload characteristic point is detected, deployment should rely on the overload. However, the pure time deployment control has a longer delay and lower accuracy; therefore, the pure time-based deceleration parachute deployment should be designed later than the normal distribution of the deceleration parachute based on "overload + delay." The timing of "overload + delay primary parachute deployment (deceleration parachute)" should precede that of "overload + delay backup parachute deployment (deceleration parachute)," and the timing of "overload + delay backup parachute deployment (deceleration parachute removal)" should precede that of "pure time backup parachute deployment control (deceleration parachute)." In other words:

[0129] Tb+TTA+Tc>Tb+TTB+Te,Ta>Tb+TTA+Tc+Tg

[0130] Where TTA is the time when overload target point a is detected; TTB is the time when overload target point b is detected.

[0131] Preferably, the pure time-backup umbrella opening control mode is as follows:

[0132] At time parameter Ta, a deceleration command is sent, and after a delay of time parameter Th, a deceleration disengagement command is sent to ensure the lower limit condition for parachute opening.

[0133] Preferably, the overload delay backup parachute opening control mode specifically involves sending a deceleration command at time Tc and a deceleration command after a delay time Tg.

[0134] Example

[0135] This embodiment provides a highly reliable parachute deployment control method for ballistic entry spacecraft, comprising the following steps:

[0136] Step 1:

[0137] Determine the overload value Ga(g) at target point a in the overload rising phase and the overload value Gb(g) at target point b in the overload falling phase. The overload sensor sensitivity is Sens(V / g), the AD chip reference voltage is Ref(V), and the digital input is n significant bits. The results are calculated using a unipolar AD chip.

[0138] The theoretical overload zero-point voltage is: Ref / 2,

[0139] The theoretical voltage value at target point a is: Ref / 2 + Ga × Sens.

[0140] The theoretical voltage value at target point b is: Ref / 2 + Gb × Sens.

[0141] The theoretical voltage at target point a, converted to a digital quantity, is: (Ref / 2 + Ga × Sens) × (2 n -1) / Ref,

[0142] The theoretical voltage at target point b, converted to a digital value, is: (Ref / 2 + Gb × Sens) × (2 n -1) / Ref,

[0143] The voltage value at target point a relative to zero is: Ga × Sens.

[0144] The voltage value at target point b relative to the zero position is: Gb × Sens.

[0145] The voltage at target point a relative to zero is converted to a digital quantity as: Ga × Sens × (2 n -1) / Ref,

[0146] The voltage at target point b relative to zero is converted to a digital quantity as: Gb × Sens × (2 n -1) / Ref.

[0147] The specified normal range for the zero-point output voltage of the overload sensor is: [Ref / 2 - Vd, Ref / 2 + Vu].

[0148] The zero-point output voltage of the overload sensor, converted to a digital value, is: [(Ref / 2-Vd)×Sens×(2 n -1) / Ref,(Ref / 2+Vu)×Sens×(2 n -1) / Ref]

[0149] The calculated Ga×Sens×(2) n -1) / Ref,Gb×Sens×(2 n -1) / Ref,(Ref / 2-Vd)×Sens×(2 n -1) / Ref,(Ref / 2+Vu)×Sens×(2 n -1) / Ref is embedded into the recycling control program parameter list as a parameter.

[0150] Step Two:

[0151] After the recovery control program is powered on, the return capsule is in an overload 0g state. The program first performs zero-point calibration. The program converts the overload voltage value output by the overload sensor from analog to digital, filters it, and stores the zero-point measurement digital value GZ_zero into a register for use in steps three and four of target discrimination and detection.

[0152] Determine if the overload sensor zero-point output is within the range of: [(Ref / 2-Vd)×Sens×(2 n -1) / Ref,(Ref / 2+Vu)×Sens×(2 n Within the range of -1) / Ref], when the zero position exceeds the normal range, an external prompt is made to indicate whether to take measures to restore the fault.

[0153] The program uses a delay process. Once it enters the return segment and starts working, the program proceeds to step three.

[0154] Step 3:

[0155] During the re-entry process, the system first enters the overload rise phase. The overload voltage value measured by the overload sensor is converted from analog to digital, then filtered. The filtered digital overload value GZ_value_fit is then compared with the overload zero value GZ_zero. If GZ_value_fit is greater than GZ_zero, zero drift elimination is performed using the difference between the filtered value and the overload zero value: GZ_value_fit = GZ_value_fit - GZ_zero. If the filtered value is less than or equal to the overload zero value, the filtered digital overload value is forced to GZ_value_fit = 0. Then, the difference and the digital threshold Ga×Sens×(2) of the target point a relative to the zero position are calculated. n -1) / Ref is compared:

[0156] GZ_value_fit≥Ga×Sens×(2 n When -1) / Ref, the corresponding channel accumulation register is incremented;

[0157] GZ_value_fit <Ga×Sens×(2 n When -1) / Ref, the corresponding channel accumulation register is cleared.

[0158] Once the cumulative time requirement is met, the overload rise segment target point a is considered to have been successfully detected.

[0159] The trajectory is analyzed, and the time from the target point a to the overload peak is T4(s). After a delay of T(s), proceed to step four.

[0160] T(s) uses point mass trajectory calculation, treating the parachute and the recovered material as a single point mass. It utilizes the first-order differential equation of motion, with time t as the calculation step, and employs the Runge-Kutta calculation method to calculate displacement, velocity, overload, etc., within each time t. T is the time interval between the peak time of overload and the overload target point a.

[0161] Step Four:

[0162] Upon re-entry into the overload descent phase, the overload voltage value measured by the overload sensor is converted from analog to digital, then filtered. The filtered digital overload value GZ_value_fit is then compared to the overload zero value GZ_zero. If GZ_value_fit is greater than GZ_zero, zero drift is eliminated using the difference between the filtered value and the overload zero value: GZ_value_fit = GZ_value_fit - GZ_zero. If the filtered value is less than or equal to the overload zero value, the filtered digital overload value is forced to GZ_value_fit = 0. Then, the difference and the digital threshold Gb × Sens × (2) of the target point b relative to the zero position are calculated. n -1) / Ref is compared:

[0163] GZ_value_fit≤Gb×Sens×(2 n When -1) / Ref, the corresponding channel accumulation register is incremented;

[0164] GZ_value_fit>>Gb×Sens×(2 n When -1) / Ref, the corresponding channel accumulation register is cleared.

[0165] Once the cumulative time requirement is met, the overload descent target point b is considered to have been successfully detected.

[0166] (3) Multi-mode combined control technology solution

[0167] The parachute deployment method can be controlled by combining multiple modes, including "overload + delayed primary parachute deployment control," "overload + delayed backup parachute deployment control," and "pure time backup parachute deployment control," to ensure that parachute deployment control can still be completed even if the overload sensor circuit fails. The design prioritizes "overload + delayed primary parachute deployment" over "overload + delayed backup parachute deployment" over "pure time backup parachute deployment control," with the following specific steps:

[0168] Step 1: Determine the time parameters corresponding to the overload target point.

[0169] Ta: Time parameters for pure time-based parachute opening mode;

[0170] Tb: Protection time parameter to prevent overload detection from interfering with the separation of the return capsule from the main detector;

[0171] Tc: The time parameter for the backup parachute deployment mode, with target point a in the overload ascent phase as the backup parachute deployment mode;

[0172] Td: The time parameter from the overload target point a to the overload peak value;

[0173] Te: Time parameters for parachute deployment mode with target point b during overload descent as the primary component;

[0174] Tf: Overload + Delay main parachute opening mode deceleration parachute working time parameter;

[0175] Tg: Overload + Delayed Backup Parachute Opening Mode Deceleration Parachute Working Time Parameter;

[0176] Th: Parachute operating time parameters in pure time-backup deployment mode.

[0177] The above times are stored as parameters in the recycling control program parameter list, and the T1 to T8 registers are used for timing.

[0178] T1: Pure time umbrella opening mode timing register;

[0179] T2: Protection timer register to prevent overload detection from interfering with separation of the return capsule from the main detector;

[0180] T3: Timer register for backup parachute opening mode with target point a of the overload ascent phase as the backup parachute opening mode;

[0181] T4: Timing register for the time from overload target point a to overload peak value;

[0182] T5: Timer register for parachute opening mode with overload descent target point b as the main component;

[0183] T6: Overload + Delay Main Parachute Opening Mode Deceleration Parachute Working Time Timing Register;

[0184] T7: Overload + Delayed Backup Parachute Opening Mode Deceleration Parachute Working Time Timing Register;

[0185] T8: Time-based backup parachute opening mode deceleration parachute working time timing register.

[0186] Step 2: After the recovery control program is powered on, perform overload zero-position calibration according to Step 2 of the overload zero-drift elimination technical solution. After calibration, proceed to Step 3.

[0187] Step 3: Wait for the external input signal "Pyrotechnic Main Line On". This signal is given at the zero point of the pure time umbrella opening T1. When the program reads that the "Pyrotechnic Main Line On" signal is valid, initialize the T1 and T2 registers, start the register timing, and proceed to step 10 when the time in the T1 register reaches the threshold Ta, and proceed to step 4 when the time in the T2 register reaches the threshold Tb.

[0188] Step 4: Detect the overload target point a according to Step 3 of the overload zero drift elimination technology solution. At the same time, determine whether the time of the T1 register has reached the threshold Ta. If it has, proceed to Step 10. After detecting the overload target point a, proceed to Step 5.

[0189] Step 5: Skip the overload peak by time delay and enter the overload descent phase. Initialize T3 and T4 registers, start register timing, and at the same time determine whether the time of T1 register has reached the threshold Ta. If it has, proceed to step 10. When the time of T3 register reaches the threshold Tc, proceed to step 9. When the time of T4 register reaches the threshold Td, proceed to step 6.

[0190] Step Six: Detect the overload target point b according to Step Four in the overload zero drift elimination technology solution. At the same time, determine whether the time of the T1 register has reached the threshold Ta. If it has, proceed to Step Ten. When the time of the T3 register reaches the threshold Tc, proceed to Step Nine. When the overload target point b is detected, proceed to Step Seven.

[0191] Step 7: Initialize the T5 register, start the register timer, and at the same time determine whether the T1 register time has reached the threshold Ta. If it has, proceed to step 10. When the T3 register time reaches the threshold Tc, proceed to step 9. When the T5 register time reaches the threshold Te, proceed to step 8.

[0192] Step 8: For overload + delay main parachute opening mode control, first send the parachute launch command, and then send the parachute disengagement command after a delay of Tf through register T6.

[0193] Step 9: For overload + delayed backup parachute opening mode control, first send the parachute launch command, and then send the parachute disengagement command after a delay of Tg through register T7.

[0194] Step 10: For pure time-backup parachute deployment mode control, first send the parachute launch command, and then send the parachute disengagement command after a delay of Th through register T8.

[0195] (1) Specific implementation case of overload zero drift elimination technology solution

[0196] For overload-time umbrella opening control, three overload sensors are selected. Following zero-point calibration, the detection of target point a and then target point b is performed sequentially. The specific steps are as follows:

[0197] Step 1:

[0198] Determine the overload value Ga (5g) at target point a in the overload rising phase and the overload value Gb (4g) at target point b in the overload falling phase. The overload sensor sensitivity is Sens (0.2V / g), the AD chip used is B128S102RH, the reference voltage is Ref (5V), and the digital effective number n = 12 bits.

[0199] The theoretical overload zero-point voltage is 2.5V.

[0200] The theoretical voltage at target point a is 3.5V.

[0201] The theoretical voltage at target point b is 3.3V.

[0202] The theoretical voltage at target point a, converted to a digital value, is 2867.

[0203] The theoretical voltage at target point b, converted to a digital value, is 2703.

[0204] The voltage value at target point a relative to zero position is 1V.

[0205] The voltage at target point b relative to zero is 0.8V.

[0206] The voltage at target point a relative to zero is converted to a digital value of 819.

[0207] The voltage at target point b relative to zero is converted to a digital value of 655.

[0208] The normal range for the zero-point output voltage of the overload sensor is [2V, 3V].

[0209] The zero-point output voltage of the overload sensor, converted to a digital value, is: [1638, 2457].

[0210] The calculated values ​​of 819, 655, 1638, and 2457 are incorporated into the recycling control program parameter list as parameters.

[0211] Step Two:

[0212] After the recovery control program is powered on, the return capsule is in an overload 0g state. The program first performs zero-point calibration. The program converts the overload voltage value output by the overload sensor from analog to digital and then filters it. The zero-point measurement digital values ​​GZ_Z1, GZ_Z2, and GZ_Z3 are stored in registers for use in steps three and four for target discrimination and detection.

[0213] The zero-point output of the overload sensor determines whether GZ_Z1, GZ_Z2, and GZ_Z3 are within the range of [1638, 2457]. If the zero point exceeds the normal range, it prompts whether external measures should be taken to restore the fault.

[0214] The program uses a delay process. Once it enters the return segment and starts working, the program proceeds to step three.

[0215] Step 3:

[0216] During the reentry process, the system first enters the overload rise phase. The overload voltage value measured by the overload sensor is converted into G1, G2, and G3 changes via analog-to-digital conversion. Then, a truncated average filter is applied. The filtered overload digital values ​​G1_fit, G2_fit, and G3_fit are compared with the overload zero values ​​GZ_Z1, GZ_Z2, and GZ_Z3, respectively. If the filtered value is greater than the overload zero value, zero drift elimination is performed using the difference between the filtered value and the overload zero value: G1_fit = G1_fit - GZ_1, G2_fit = G2_fit - GZ_2, G3_fit = G3_fit - GZ_3. If the filtered value is less than or equal to the overload zero value, the filtered overload digital values ​​are forced to G1_fit = 0, G2_fit = 0, and G3_fit = 0. Finally, the difference is compared with the digital threshold value of 1229 relative to the zero position of the target point a.

[0217] G1_fit>=1229, increment the corresponding channel accumulation register M1;

[0218] G2_fit>=1229, increment the count in the corresponding channel accumulation register M2;

[0219] G3_fit>=1229, increment the corresponding channel accumulation register M3;

[0220] When G1_fit < 1229, the corresponding channel accumulation register M1 is cleared.

[0221] When G2_fit < 1229, the corresponding channel accumulation register M2 is cleared.

[0222] When G3_fit < 1229, the corresponding channel accumulation register M3 is cleared.

[0223] When two of the three sensors cumulatively meet the 100ms requirement, the overload rise segment target point a is considered to have been successfully detected.

[0224] The trajectory is analyzed, and the time from the target point a to the overload peak is T4 = 30 (s). After a delay of T (s), proceed to step four.

[0225] Step Four:

[0226] Upon re-entry into the overload descent phase, the overload voltage value measured by the overload sensor is converted from analog to digital into G1, G2, and G3 changes. These are then truncated and averaged using a filter. The filtered overload digital values ​​G1_fit, G2_fit, and G3_fit are compared with the overload zero values ​​GZ_Z1, GZ_Z2, and GZ_Z3, respectively. If the filtered value is greater than the overload zero value, zero drift is eliminated using the difference between the filtered value and the overload zero value: G1_fit = G1_fit - GZ_1, G2_fit = G2_fit - GZ_2, G3_fit = G3_fit - GZ_3. If the filtered value is less than or equal to the overload zero value, the filtered overload digital values ​​are forced to G1_fit = 0, G2_fit = 0, and G3_fit = 0. Finally, the difference is compared with the digital threshold value of 1065 relative to the zero position at target point b.

[0227] G1_fit<=1065, increment the count in the corresponding channel accumulation register M1;

[0228] G2_fit<=1065, increment the count in the corresponding channel accumulation register M2;

[0229] G3_fit<=1065, increment the corresponding channel's cumulative register M3;

[0230] When G1_fit>1065, the corresponding channel accumulation register M1 is cleared.

[0231] When G2_fit>1065, the corresponding channel accumulation register M2 is cleared.

[0232] When G3_fit>1065, the corresponding channel accumulation register M3 is cleared.

[0233] When two of the three sensors cumulatively meet the 100ms time requirement, the overload descent target point b is considered to have been successfully detected.

[0234] (3) Multi-mode combined control technology solution

[0235] The parachute deployment method can be controlled by combining multiple modes, including "overload + delayed primary parachute deployment control," "overload + delayed backup parachute deployment control," and "pure time backup parachute deployment control," to ensure that parachute deployment control can still be completed even if the overload sensor circuit fails. The design prioritizes "overload + delayed primary parachute deployment" over "overload + delayed backup parachute deployment" over "pure time backup parachute deployment control," with the following specific steps:

[0236] Step 1: Determine the time parameters corresponding to the overload target point.

[0237] Ta: 77min10;

[0238] Tb: 20min;

[0239] Tc: 78.6s;

[0240] Td: 30s;

[0241] Te: 20.6s;

[0242] Tf: 135s;

[0243] Tg: 135s;

[0244] Th: 20s.

[0245] The above times are stored as parameters in the recycling control program parameter list, and the T1 to T8 registers are used for timing.

[0246] T1: Pure time umbrella opening mode timing register;

[0247] T2: Protection timer register to prevent overload detection from interfering with separation of the return capsule from the main detector;

[0248] T3: Timer register for backup parachute opening mode with target point a of the overload ascent phase as the backup parachute opening mode;

[0249] T4: Timing register for the time from overload target point a to overload peak value;

[0250] T5: Timer register for parachute opening mode with overload descent target point b as the main component;

[0251] T6: Overload + Delay Main Parachute Opening Mode Deceleration Parachute Working Time Timing Register;

[0252] T7: Overload + Delayed Backup Parachute Opening Mode Deceleration Parachute Working Time Timing Register;

[0253] T8: Time-based backup parachute opening mode deceleration parachute working time timing register.

[0254] Step 2: After the recovery control program is powered on, perform overload zero-position calibration according to Step 2 of the overload zero-drift elimination technical solution. After calibration, proceed to Step 3.

[0255] like Figure 3 As shown, step three: wait for the external input signal "fireworks main line connected". The timing of this signal is the zero point of the pure time umbrella opening T1. When the program reads that the "fireworks main line connected" signal is valid, initialize the T1 and T2 registers, start the register timing, and when the time in the T1 register reaches the threshold Ta, proceed to step ten. When the time in the T2 register reaches the threshold Tb, proceed to step four.

[0256] Step 4: Detect the overload target point a according to Step 3 of the overload zero drift elimination technology solution. At the same time, determine whether the time of the T1 register has reached the threshold Ta. If it has, proceed to Step 10. After detecting the overload target point a, proceed to Step 5.

[0257] Step 5: Skip the overload peak by time delay and enter the overload descent phase. Initialize T3 and T4 registers, start register timing, and at the same time determine whether the time of T1 register has reached the threshold Ta. If it has, proceed to step 10. When the time of T3 register reaches the threshold Tc, proceed to step 9. When the time of T4 register reaches the threshold Td, proceed to step 6.

[0258] Step Six: Detect the overload target point b according to Step Four in the overload zero drift elimination technology solution. At the same time, determine whether the time of the T1 register has reached the threshold Ta. If it has, proceed to Step Ten. When the time of the T3 register reaches the threshold Tc, proceed to Step Nine. When the overload target point b is detected, proceed to Step Seven.

[0259] Step 7: Initialize the T5 register, start the register timer, and at the same time determine whether the T1 register time has reached the threshold Ta. If it has, proceed to step 10. When the T3 register time reaches the threshold Tc, proceed to step 9. When the T5 register time reaches the threshold Te, proceed to step 8.

[0260] Step 8: For overload + delay main parachute opening mode control, first send the parachute launch command, and then send the parachute disengagement command after a delay of Tf through register T6.

[0261] Step 9: For overload + delayed backup parachute opening mode control, first send the parachute launch command, and then send the parachute disengagement command after a delay of Tg through register T7.

[0262] Step 10: For pure time-backup parachute deployment mode control, first send the parachute launch command, and then send the parachute disengagement command after a delay of Th through register T8.

[0263] Although the present invention has been described in detail through the preferred embodiments above, it should be understood that the above description should not be considered as a limitation of the present invention. Various modifications and substitutions to the present invention will be apparent to those skilled in the art after reading the above description. Therefore, the scope of protection of the present invention should be defined by the appended claims.

[0264] The contents not described in detail in this specification are common knowledge to those skilled in the art.

Claims

1. A high-reliability method of controlling the opening of a parachute for ballistic entry into a spacecraft, characterized in that, Comprise the following steps: S1, determine the time parameter Ta~Th corresponding to the overload target point and the corresponding T1~T8 register; S2, recycle control program power on; S3, overload zero calibration; S4, when receiving external input instruction, start T1 register and T2 register timing, when T1 register reaches threshold Ta, then enter step S11; when T2 register time reaches threshold Tb, then enter step S5; S5, overload target point a detection, when T1 register time reaches time Ta, then enter step S11; when the overload target point a is detected and T1 register time does not reach time Ta, enter step S6; Otherwise, repeat step S5; S6, start T3 and T4 register timing, and judge whether T1 register time reaches time Ta, if yes, enter step S11; when T3 register time reaches time Tc, enter step S10; when T4 register time reaches time Td, enter step S7; S7, overload target point b detection, judge whether T1 register time reaches time Ta, if yes, then enter step S11; When T3 register time reaches time Tc and the overload descent target point b is detected, enter step S8; when T3 register time does not reach time Tc and the overload descent target point b is detected, enter step S8; When T3 register time reaches time Tc and the overload descent target point b is not detected, enter step S10; Otherwise, repeat step S7; S8, start T5 register timing, judge whether T1 register time reaches time Ta, if yes, then enter step S11; when T3 register time reaches time Tc, enter step S10; when T5 register time reaches threshold Te, enter step S9; S9, send the parachute opening instruction, send the parachute release instruction after T6 register delay Tf; S10, send the parachute opening instruction, send the parachute release instruction after T7 register delay Tg; S11, send the parachute opening instruction, send the parachute release instruction after T8 register delay Th; The time parameter corresponding to the overload target point is: Ta: pure time opening parachute mode time parameter; Tb: protection time parameter for avoiding the interference of return capsule and main probe separation on overload detection; Tc: time parameter for backup opening parachute mode with overload rising target point a; Td: time parameter from overload target point a to overload peak; Te: time parameter for main opening parachute mode with overload descent target point b; Tf: time parameter for overload + delay main opening parachute mode deceleration parachute working time; Tg: time parameter for overload + delay backup opening parachute mode deceleration parachute working time; Th: pure time backup opening parachute mode deceleration parachute working time parameter.

2. A high-reliability control method for opening a parachute of a ballistic entry spacecraft according to claim 1, characterized in that: The determination of the time parameter corresponding to the overload target point and the corresponding timing register is: The time parameter Ta~Th corresponding to the overload target point is solidified into the parameter list of the recycle control program in the form of parameter, and T1~T8 register timing is used; T1: pure time opening parachute mode timing register; T2: protection time timing register for avoiding the interference of return capsule and main probe separation on overload detection; T3: Time register of backup opening mode with overload rising segment target point a; T4: Time register of overload target point a to overload peak; T5: Time register of main opening mode with overload falling segment target point b; T6: Time register of deceleration parachute working time of main opening mode with overload + delay; T7: Time register of deceleration parachute working time of backup opening mode with overload + delay; T8: Time register of deceleration parachute working time of pure time backup opening mode.

3. The high-reliability control method for opening a parachute of a ballistic entry spacecraft according to claim 1, characterized by: The overload zero calibration comprises the following steps: calculating the range of the overload sensor zero output voltage value; judging whether the overload sensor zero output voltage value is out of the range, and if so, prompting external measures to recover from the fault.

4. The high-reliability control method for opening a parachute of a ballistic entry spacecraft according to claim 1, characterized by: The range of the overload sensor zero output voltage value is as follows: [(Ref / 2 - Vd) x Sens x (2 n -1) / Ref, (Ref / 2 + Vu) x Sens x (2 n -1) / Ref] wherein, Ref / 2 is the overload zero theoretical voltage value, Vd is the maximum lower deviation of the overload sensor zero drift, Vu is the maximum upper deviation of the overload sensor zero drift, Sens is the overload sensor sensitivity, n is the digital effective bit, and Ref is twice the overload zero theoretical voltage value Ref / 2.

5. The method of claim 1, wherein: The overload target point a detection comprises the following steps: GZ_value_fit≥F1, the corresponding cumulative register count value is accumulated; GZ_value_fit<F1, the corresponding cumulative register count value is cleared; Wherein, F1 = Ga x Sens x (2 n -1) / Ref; F1 is a digital threshold value of the target point a relative to the zero position, GZ_value_fit is the filtered overload digital value, Ga is the overload value of the target point a in the overload rising section, Sens is the sensitivity of the overload sensor, Ref is the reference voltage of the AD chip, and n is the digital effective bit. When the cumulative register count value meets the time requirement, the overload target point a detection in the rising segment is successful.

6. The method of claim 1, wherein: The overload target point b detection comprises the following steps: GZ_value_fit≤F2, the corresponding cumulative register count value is accumulated; GZ_value_fit>F2, the corresponding cumulative register count value is cleared; Wherein, F2 = Gb x Sens x (2 n -1) / Ref; F2 is the digital threshold of the target point b relative to the zero position; GZ_value_fit is the filtered overload digital quantity, Gb is the overload value of the target point b in the overload descending section, Sens is the overload sensor sensitivity, Ref is the AD chip reference voltage, and n is the digital effective bit. When the cumulative register count value meets the time requirement, the overload target point b detection in the falling segment is successful.

7. The high-reliability parachute opening control method for a ballistic entry spacecraft according to claim 5 or 6, characterized in that: if GZ_value_fit>GZ_zero, GZ_value_fit=GZ_value_fit-GZ_zero; if GZ_value_fit≤GZ_zero, GZ_value_fit=0; wherein, GZ_value_fit is the filtered overload digital value, and GZ_zero is the overload zero value.

8. The high-reliability parachute opening control method for a ballistic entry spacecraft according to claim 2, characterized in that: Tb+TTA+Tc>Tb+TTB+Te, Ta>Tb+TTA+Tc+Tg wherein, TTA is the time of detecting the overload target point a, and TTB is the time of detecting the overload target point b.

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