High-reliability parachute opening control method for entering spacecraft in ballistic manner

Abstract

The invention discloses a high-reliability parachute opening control method for entering a spacecraft in a ballistic manner, which comprises the following steps: enabling a whole device to be in a 0g overload time period before the spacecraft reenters, acquiring overload sensor information of each channel by software, filtering to obtain an overload zero value, storing the overload zero value into a register, and when a zero output voltage value of the overload sensor exceeds a normal range of zero drift, starting a parachute opening process; according to the recovery control system, fault recovery can be carried out by prompting external power-up again, the problem of circuit fault of the overload sensor due to the single event effect before return and reentry can be solved, and the difference value between the measured overload value and the zero value in the working process of the recovery control system is judged; by utilizing the characteristic that the sensitivity of the overload sensor does not change along with time, the influence of parachute opening trigger time sequence precision deviation caused by zero drift of the overload sensor when the task detection time is relatively long is eliminated. According to the multi-mode combined control method adopted by the invention, an overload time parachute opening control method and a pure time parachute opening control method are combined to form the multi-mode control method.

Description

Technical Field

[0001] The invention relates to a high-reliability parachute opening control method for ballistic entry into a spacecraft, and belongs to the technical field of intelligent control. Background Art

[0002] Entry refers to two tasks: deceleration after entering the atmosphere of an extraterrestrial body and returning to the Earth. "Return" is used as an abbreviation below to replace the two tasks. The return landing of a returning spacecraft generally refers to the process from entering the atmosphere from one side of the universe across the Karman line at an altitude of 100km to landing. In this process, the environment in which the spacecraft is located is complex and changeable. Accurate parachute deceleration and buffer control are crucial. Opening the parachute too early will cause the parachute to be damaged by large dynamic pressure, and opening the parachute too late will cause insufficient deceleration time and excessive landing speed of the spacecraft. Both will cause the deceleration of the spacecraft recovery system and the decline of landing buffer performance. Most deep space exploration spacecraft use ballistic reentry as the return method, and generally require the overload-time method to control the opening of the parachute. Traditional returning satellites use mechanical acceleration switch products to measure ballistic acceleration. The weight of a single product is about 150g, the processability is slightly poor, the yield is low, and it cannot meet the needs of miniaturization. The patent "A light and small high-reliability control system and method for small celestial body detection and return" (202218007998.3, inventor: Sun Xiyun, etc.) relates to a light and small high-reliability control system and method for small celestial body detection and return. The dual-machine four-mode software architecture is used to ensure the reliability of the control system. The optimal overload-time feature point selection method is used to perform data analysis on n return trajectory overload curves, and the optimal ascending and descending overload discrimination feature points based on dynamic pressure are given. An overload-time primary and backup parachute opening control method is designed, and a filtering sliding window detection is used for overload information. The primary and backup parachute opening points are found according to the feature points selected by the optimal overload-time feature point selection method. This method has the following defects: (1) When the detection mission time is long, for example, the small celestial body detection mission is 2 to 3 years, the zero position of the overload sensor will drift, and the use of 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 some common cause aging, a failure mode of overload judgment failure will result. In order 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 detection and return".

[0003] Problems:

[0004] When the exploration mission is long, for example, the exploration mission of a small celestial body is 2 to 3 years, the zero position of the overload sensor will drift. The use of a fixed threshold to determine the overload parachute trigger point will result in parachute control timing accuracy deviation. When the whole device is in the 0g overload period before reentry, the software collects the information of each overload sensor and processes it to obtain the overload zero position value and stores it in the register. During the operation of the recovery control system, the measured overload value is compared with the zero position for judgment, and the characteristic that the sensitivity of the overload sensor does not change with time is used to eliminate the influence of the parachute trigger timing accuracy deviation caused by the overload zero drift.

[0005] Although the overload sensor can form a three-out-of-two redundant mode and the A / D conversion circuit can form a parallel redundant mode, when the common cause output of the overload sensor is too low, or the common cause of the A / D conversion circuit causes an open circuit or a short circuit, the recovery controller will not be able to read the reentry overload signal and the subsystem will not be able to automatically execute the parachute opening procedure. In order to cope 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 method is adopted.

[0006] On-orbit overload drift elimination is mostly used in the field of space exploration represented by small celestial body exploration. No relevant information has been found on the overload drift elimination method during the return process. Summary of the invention

[0007] The technical problem solved by the present invention is: to overcome the deficiencies of the prior art, to provide a highly reliable parachute opening control method for ballistic entry spacecraft, and to solve the problem of failure to open the parachute due to multiple sensor failures caused by common cause failures.

[0008] The technical solution of the present invention is:

[0009] The present invention discloses a high-reliability parachute opening control method for ballistic entry into a spacecraft, comprising the following steps:

[0010] S1, determine the time parameters Ta~Th corresponding to the overload target point and the corresponding T1~T8 registers;

[0011] S2, power on the recycling control program;

[0012] S3, perform overload zero position calibration;

[0013] S4, when receiving an external input instruction, start the timing of the T1 register and the T2 register. When the T1 register reaches the threshold value Ta, enter step S11; when the T2 register time reaches the threshold value Tb, enter step S5;

[0014] S5, detect the overload target point a, when the T1 register time reaches the time Ta, go to step S11; when the overload target point a is detected and the T1 register time does not reach the time Ta, go to step S6; otherwise, repeat step S5;

[0015] S6, start the timing of T3 and T4 registers, and determine whether the T1 register time reaches the time Ta. If so, proceed to step S11; when the T3 register time reaches the time Tc, proceed to step S10; when the T4 register time reaches the time Td, proceed to step S7;

[0016] S7, perform overload target point b detection, determine whether T1 register time reaches time Ta, if so, proceed to step S11; when T3 register time reaches time Tc and overload descending segment target point b is detected, proceed to step S8; when T3 register time does not reach time Tc and overload descending segment target point b is detected, proceed to step S8; when T3 register time reaches time Tc and overload descending segment target point b is not detected, proceed to step S10; otherwise, repeat step S7;

[0017] S8, start the T5 register timing, determine whether the T1 register time reaches the time Ta, if so, go to step S11; when the T3 register time reaches the time Tc, go to step S10; when the T5 register time reaches the threshold Te, go to step S9;

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

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

[0020] S11, send the command to put the parachute in place, and send the command to take off the parachute after a delay of Th through the T8 register.

[0021] Furthermore, in the above control method, the time parameter corresponding to the overload target point and the corresponding timing register are determined as follows:

[0022] The time parameters corresponding to the overload target point are:

[0023] Ta: time parameter of pure time parachute opening mode;

[0024] Tb: protection time parameter to prevent the return capsule from separating from the main probe and interfering with overload detection;

[0025] Tc: Time parameter for backup parachute opening mode with the target point a in the overload ascent phase;

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

[0027] Te: time parameter of parachute opening mode with overload descent target point b as the main part;

[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: Working time parameter of the deceleration parachute in pure time backup parachute opening mode.

[0031] The above time is solidified in the parameter form into the recycling control program parameter list, and the time is measured using the T1~T8 registers;

[0032] T1: pure time parachute mode timing register;

[0033] T2: A protection time timing register to prevent the return capsule from separating from the main probe and interfering with overload detection;

[0034] T3: The time timing register of the backup parachute opening mode with the overload ascent stage target point a as the time timing register;

[0035] T4: Time timing register from overload target point a to overload peak value;

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

[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: Pure time backup parachute opening mode deceleration parachute working time timing register.

[0040] Furthermore, in the above control method, the overload zero position calibration is specifically performed as follows:

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

[0042] Determine whether the zero-position output voltage value of the overload sensor is out of range. If so, prompt the external device to take measures to recover from the fault.

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

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

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

[0046] Furthermore, in the above control method, the overload target point a is detected by:

[0047] When GZ_value_fit≥F1, the count value of the corresponding channel accumulation register is accumulated;

[0048] When GZ_value_fit<F1, the corresponding channel cumulative register count value is cleared;

[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 overload digital value after filtering, Ga is the overload value of 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;

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

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

[0052] When GZ_value_fit≤F2, the count value of the corresponding channel accumulation register is accumulated;

[0053] When GZ_value_fit>F2, the corresponding channel cumulative register count value is cleared;

[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 drop section, Sens is the overload sensor sensitivity, Ref is the AD chip reference voltage, and n is the digital effective bit;

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

[0056] Furthermore, in the above control method,

[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] Among them, GZ_value_fit is the overload digital value after filtering; GZ_zero is the overload zero value.

[0060] Furthermore, in the above control method,

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

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

[0063] The beneficial effects of the present invention and the prior art are:

[0064] (1) The present invention collects information from each overload sensor and processes it to obtain the overload zero value when the whole device is in the 0g overload time 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 the outside to take measures and re-power on to recover from the fault, which can solve the problem of overload sensor circuit failure due to single particle effect before reentry.

[0065] (2) During the operation of the recovery control system, the present invention compares the measured overload value with the zero position for judgment, utilizes the characteristic that the sensitivity of the overload sensor does not change with time, and thus eliminates the influence of the parachute opening trigger timing accuracy deviation caused by the overload zero drift, thereby solving the problem of poor parachute opening control accuracy caused by the long-term zero drift of the capacitive overload sensor on orbit when the ballistic return overload delay control parachute is adopted.

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

[0067] (4) Based on the fact that the reliability of multi-mode arbitration is higher than the accuracy of re-entry time control and combined with the optimal result of parachute opening distribution, the present invention designs the time point of "overload + delayed main parachute opening" to be earlier than the time point of "overload + delayed backup parachute opening", and the time point of "overload + delayed backup parachute opening" to be earlier than the "pure time backup parachute opening control", thus solving the combined logical relationship of the three parachute opening control modes.

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

[0069] (6) The present invention starts the pure time parachute opening control time timer by setting an input command. If the overload sensor fails and cannot detect the overload descent section target point b, the overload backup parachute opening control is relied upon to ensure reliable conditions for parachute opening.

[0070] (7) The present invention sets a protection time timing register, during which only pure time parachute opening timing is performed, and no judgment is made on the overload target point, so as to avoid interference of the overload detection 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 return separation when the parachute opening control is performed using the overload full curve trend.

[0071] (8) The present invention sets a protection time timing register, and utilizes the change trend of the ballistic reentry overload curve to detect point a in the ascending section, delay and stagger the overload peak, and then detect point b in the descending section, so as to avoid signal jitter in the overload ascending section and detect point b in the overload descending section in advance, resulting in premature parachute opening. BRIEF DESCRIPTION OF THE DRAWINGS

[0072] Figure 1 It is a schematic diagram of the time relationship of three parachute opening control modes on the overload-time curve of the present invention;

[0073] Figure 2 A schematic diagram of the flow chart of the timer design in the control mode switching of the three parachute opening control modes according to the present invention;

[0074] Figure 3 It is a schematic diagram of the process of sampling and processing three-channel overload data of the overload zero drift elimination technology of the present invention. DETAILED DESCRIPTION

[0075] The present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0076] The present invention discloses a highly reliable parachute opening control method for ballistic entry into a spacecraft. Before the spacecraft reenters, the whole device is in a 0g overload time period. The software collects the information of overload sensors of each channel and filters it to obtain the overload zero-position value and stores it in a register. When the zero-position output voltage value of the overload sensor exceeds the normal range of the zero-position drift, the fault recovery can be performed by prompting the external power to be re-powered. The problem of overload sensor circuit failure due to the single particle effect before returning to reentry can be solved. During the operation of the recovery control system, the measured overload value and the zero-position value difference are judged. The characteristic that the sensitivity of the overload sensor does not change with time is used, thereby eliminating the influence of the parachute opening trigger timing accuracy deviation caused by the zero drift of the overload sensor when the detection mission time is long. The multi-mode combined control method adopted by the present invention adopts a multi-mode control method combined with an overload time parachute opening control method and a pure time parachute opening control method, and uses the pure time parachute opening control as a backup solution, which can solve the problem of being unable to open the parachute when multiple sensors fail due to common cause failure.

[0077] like Figure 2 As shown, the present invention discloses a high-reliability parachute opening control method for ballistic entry into a spacecraft, comprising the following steps:

[0078] S1, determine the time parameters Ta~Th corresponding to the overload target point and the corresponding T1~T8 registers;

[0079] S2, power on the recycling control program;

[0080] S3, perform overload zero position calibration;

[0081] S4, when receiving an external input instruction, start the timing of the T1 register and the T2 register. When the T1 register reaches the threshold value Ta, enter step S11; when the T2 register time reaches the threshold value Tb, enter step S5;

[0082] S5, detect the overload target point a, when the T1 register time reaches the time Ta, go to step S11; when the overload target point a is detected and the T1 register time does not reach the time Ta, go to step S6; otherwise, repeat step S5;

[0083] S6, start the timing of T3 and T4 registers, and determine whether the T1 register time reaches the time Ta. If so, proceed to step S11; when the T3 register time reaches the time Tc, proceed to step S10; when the T4 register time reaches the time Td, proceed to step S7;

[0084] S7, perform overload target point b detection, determine whether T1 register time reaches time Ta, if so, proceed to step S11; when T3 register time reaches time Tc and overload descending segment target point b is detected, proceed to step S8; when T3 register time does not reach time Tc and overload descending segment target point b is detected, proceed to step S8; when T3 register time reaches time Tc and overload descending segment target point b is not detected, proceed to step S10; otherwise, repeat step S7;

[0085] S8, start the T5 register timing, determine whether the T1 register time reaches the time Ta, if so, go to step S11; when the T3 register time reaches the time Tc, go to step S10; when the T5 register time reaches the threshold Te, go to step S9;

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

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

[0088] S11, send the command to put the parachute in place, and send the command to take off the parachute after a delay of Th through the T8 register.

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

[0090] The time parameters corresponding to the overload target point are:

[0091] Ta: time parameter of pure time parachute opening mode;

[0092] Tb: protection time parameter to prevent the return capsule from separating from the main probe and interfering with overload detection;

[0093] Tc: Time parameter for backup parachute opening mode with the target point a in the overload ascent phase;

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

[0095] Te: time parameter of parachute opening mode with overload descent target point b as the main part;

[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: Working time parameter of the deceleration parachute in pure time backup parachute opening mode.

[0099] The above time is solidified in the parameter form into the recycling control program parameter list, and the time is measured using the T1~T8 registers;

[0100] T1: pure time parachute mode timing register;

[0101] T2: A protection time timing register to prevent the return capsule from separating from the main probe and interfering with overload detection;

[0102] T3: The time timing register of the backup parachute opening mode with the overload ascent stage target point a as the time timing register;

[0103] T4: Time timing register from overload target point a to overload peak value;

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

[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: Pure time backup parachute opening mode deceleration parachute working time timing register.

[0108] Preferably, overload zero position calibration is performed, specifically:

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

[0110] Determine whether the zero-position output voltage value of the overload sensor is out of range. If so, prompt the external device to take measures to recover from the fault.

[0111] Preferably, the range of the overload sensor zero-position output voltage value is specifically:

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

[0113] Among them, Ref / 2 is the theoretical voltage value of the overload zero position, Vd is the maximum lower deviation of the overload sensor zero position drift, Vu is the maximum upper deviation of the overload sensor zero position drift, Sens is the sensitivity of the overload sensor, 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 accumulation register is accumulated;

[0116] When GZ_value_fit<F1, the corresponding channel cumulative register count value is cleared;

[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 overload digital value after filtering, Ga is the overload value of 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;

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

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

[0120] When GZ_value_fit≤F2, the count value of the corresponding channel accumulation register is accumulated;

[0121] When GZ_value_fit>F2, the corresponding channel cumulative register count value is cleared;

[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 drop section, Sens is the overload sensor sensitivity, Ref is the AD chip reference voltage, and n is the digital effective bit;

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

[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] Among them, GZ_value_fit is the overload digital value after filtering; GZ_zero is the overload zero value.

[0128] The parachute opening method can be controlled by combining multiple modes such as "overload + delayed main parachute opening control", "overload + delayed backup parachute opening control" and "pure time backup parachute opening control" to ensure that the parachute opening control can be completed after the overload sensor circuit fails. The program redundantly judges the overload signals of multiple channels, and the probability of multi-channel failure is relatively small. The pure time parachute opening mode can ensure the parachute opening in the mode where multiple channel overload sensors fail. Once the overload can detect the characteristic point, the parachute should be opened by overload, and the pure time parachute opening control has a long delay time and poor accuracy. Therefore, the design of the pure time method of the bullet deceleration parachute should be later than the normal distribution based on the "overload + delay" deceleration parachute removal. The design time point of "overload + delayed main parachute opening (bullet deceleration parachute)" is earlier than the time point of "overload + delayed backup parachute opening (bullet deceleration parachute)", and the time point of "overload + delayed backup parachute opening (deceleration parachute removal)" is earlier than the "pure time backup parachute opening control (bullet deceleration parachute)". That is:

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

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

[0131] Preferably, the pure time backup parachute opening control mode is specifically:

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

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

[0134] Example

[0135] This embodiment provides a high-reliability parachute opening control method for a ballistic entry spacecraft, comprising the following steps:

[0136] Step 1:

[0137] Determine the overload value Ga(g) of the target point a in the overload rising section, and the overload value Gb(g) of the target point b in the overload falling section. The sensitivity of the overload sensor is Sens(V / g), the reference voltage of the AD chip is Ref(V), and the digital effective n bits are calculated by unipolar AD chip conversion:

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

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

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

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

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

[0143] The voltage value of the target point a relative to the zero position is: Ga×Sens,

[0144] The voltage value of target point b relative to zero is: Gb×Sens,

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

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

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

[0148] The zero position output voltage of the overload sensor is converted into a digital quantity: [(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 solidified into the recycling control program parameter list in the form of parameters.

[0150] Step 2:

[0151] After the recovery control program is powered on, the return capsule is in an overload 0g state. The program first performs a zero-position calibration process. The program converts the overload voltage value output by the overload sensor into an analog-to-digital value, and then stores the zero-position measurement digital value GZ_zero into a register through filtering for use in step three and step four target identification and detection processing.

[0152] Determine whether the overload sensor zero output GZ_zero is within: [(Ref / 2-Vd)×Sens×(2 n -1) / Ref,(Ref / 2+Vu)×Sens×(2 n -1) / Ref], when the zero position exceeds the normal range, it prompts the external party whether to take measures to restore the fault.

[0153] The program goes through delay processing, and when it enters the return section and starts working, the program enters step three.

[0154] Step 3:

[0155] During the return reentry process, the overload rising section is first entered. The overload voltage value measured and output by the overload sensor is converted by analog-to-digital conversion, and then filtered. The filtered overload digital quantity GZ_value_fit is compared with the overload zero value GZ_zero. If GZ_value_fit is greater than GZ_zero, the difference between "filter value - overload zero value" is used to eliminate zero drift: GZ_value_fit = GZ_value_fit-GZ_zero; if the filter value is less than or equal to the overload zero value, the filtered overload digital quantity is forced to GZ_value_fit = 0. Then the difference and the digital threshold Ga×Sens×(2 n -1) / Ref for comparison:

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

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

[0158] After the cumulative time requirement is met, it is considered that the overload ascending section target point a is detected successfully.

[0159] Analyze the trajectory, the time from target point a to the overload peak is T4(s). After a delay of T(s), proceed to step 4.

[0160] T(s) uses particle ballistics calculation, regards the parachute and the recovered object as a particle, uses the first-order differential motion equation, takes time t as the calculation step, and adopts the Runge-Kutta calculation method to calculate the displacement, velocity, overload, etc. within each time t. T is the time interval between the peak moment of overload and the overload target point a.

[0161] Step 4:

[0162] Return to the reentry process and enter the overload drop stage. The overload voltage value measured by the overload sensor is converted by analog-to-digital conversion, and then filtered. The filtered overload digital value GZ_value_fit is compared with the overload zero value GZ_zero. If GZ_value_fit is greater than GZ_zero, the difference between "filter value - overload zero value" is used to eliminate zero drift: GZ_value_fit = GZ_value_fit-GZ_zero; if the filter value is less than or equal to the overload zero value, the filtered overload digital value is forced to GZ_value_fit = 0. Then the difference and the digital threshold value Gb×Sens×(2 n -1) / Ref for comparison:

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

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

[0165] After the cumulative time requirement is met, it is considered that the detection of target point b in the overload descent section is successful.

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

[0167] The parachute opening method can be controlled by combining multiple modes such as "overload + delayed main parachute opening control", "overload + delayed backup parachute opening control" and "pure time backup parachute opening control" to ensure that the parachute opening control can be completed after the overload sensor circuit fails. The "overload + delayed main parachute opening" is designed to precede the "overload + delayed backup parachute opening" and precede the "pure time backup parachute opening control". The specific steps are:

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

[0169] Ta: time parameter of pure time parachute opening mode;

[0170] Tb: protection time parameter to prevent the return capsule from separating from the main probe and interfering with overload detection;

[0171] Tc: Time parameter for backup parachute opening mode with the target point a in the overload ascent phase;

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

[0173] Te: time parameter of parachute opening mode with overload descent target point b as the main part;

[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: Working time parameter of the deceleration parachute in pure time backup parachute opening mode.

[0177] The above time is solidified in the form of parameters into the parameter list of the recovery control program, and the timing is performed using T1 to T8 registers.

[0178] T1: pure time parachute mode timing register;

[0179] T2: A protection time timing register to prevent the return capsule from separating from the main probe and interfering with overload detection;

[0180] T3: The time timing register of the backup parachute opening mode with the overload ascent stage target point a as the time timing register;

[0181] T4: Time timing register from overload target point a to overload peak value;

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

[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: Pure time 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 in the overload zero drift elimination technical solution. After the calibration is completed, proceed to step 3.

[0187] Step 3: Wait for the external input signal "fireworks positive line through", which sets the timing as the time zero of pure time parachute opening T1. When the program reads that the "fireworks positive line through" signal is valid, initialize T1 and T2 registers, start register timing, and enter step ten when the T1 register time reaches the threshold Ta, and enter step four when the T2 register time reaches the threshold Tb.

[0188] Step 4: Detect the overload target point a according to step 3 in the overload zero drift elimination technical solution, and determine whether the T1 register time reaches the threshold Ta. If it reaches it, proceed to step 10. When the overload target point a is detected, proceed to step 5.

[0189] Step 5: Skip the overload peak through time delay and enter the overload drop stage, initialize T3 and T4 registers, start register timing, and determine whether the T1 register time reaches the threshold Ta. If it reaches it, proceed to step ten. When the T3 register time reaches the threshold Tc, proceed to step nine. When the T4 register time reaches the threshold Td, proceed to step six.

[0190] Step 6: Detect the overload target point b according to step 4 in the overload zero drift elimination technical solution, and determine whether the T1 register time reaches the threshold Ta. If it reaches it, proceed to step 10. When the T3 register time reaches the threshold Tc, proceed to step 9. When the overload target point b is detected, proceed to step 7.

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

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

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

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

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

[0196] When overload-time parachute opening is controlled, three overload sensors are selected and executed in the order of zero point calibration, detection of target point a, and detection of target point b. The specific steps are as follows:

[0197] Step 1:

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

[0199] The overload zero position theoretical voltage is: 2.5v,

[0200] The theoretical voltage value of target point a is: 3.5v,

[0201] The theoretical voltage value of target point b is: 3.3v,

[0202] The target point a theoretical voltage is converted into digital quantity: 2867,

[0203] The target point b theoretical voltage is converted into digital quantity: 2703,

[0204] The voltage value of target point a relative to zero position is: 1v,

[0205] The voltage value of target point b relative to zero position is: 0.8v,

[0206] The voltage of target point a relative to zero is converted into digital quantity: 819,

[0207] The voltage of the target point b relative to the zero position is converted into a digital quantity: 655.

[0208] The normal range of the overload sensor zero output voltage is: [2v, 3v],

[0209] The overload sensor zero position output voltage is converted into digital quantity: [1638, 2457]

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

[0211] Step 2:

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

[0213] Determine whether the overload sensor zero position output GZ_Z1, GZ_Z2, GZ_Z3 are within the range of [1638, 2457]. When the zero position exceeds the normal range, it prompts the outside to take measures to restore the fault.

[0214] The program goes through delay processing, and when it enters the return section and starts working, the program enters step three.

[0215] Step 3:

[0216] During the return reentry process, the overload rising section is first entered. The overload voltage value measured and output by the overload sensor is converted into G1, G2, and G3 changes through analog-to-digital conversion, and then truncated average filtering is performed. The filtered overload digital quantities G1_fit, G2_fit, and G3_fit are compared with the overload zero values ​​GZ_Z1, GZ_Z2, and GZ_Z3 respectively. If the filter value is greater than the overload zero value, the difference between the filter value and the overload zero value is used to eliminate zero drift: G1_fit = G1_fit-GZ_1, G2_fit = G2_fit-GZ_2, and G3_fit = G3_fit-GZ_3; if the filter value is less than or equal to the overload zero value, the filtered overload digital quantity is forced to G1_fit = 0, G2_fit = 0, and G3_fit = 0. Then the difference is compared with the digital threshold 1229 of the target point a relative to the zero position:

[0217] G1_fit>=1229, accumulate the count of the corresponding channel accumulation register M1;

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

[0219] G3_fit>=1229, accumulate the count of 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 meet the cumulative time requirement of 100ms, it is considered that the overload rising section target point a is detected successfully.

[0224] Analyzing the trajectory, the time from the target point a to the overload peak is T4=30(s). After a delay of T(s), proceed to step 4.

[0225] Step 4:

[0226] Return to the reentry process and enter the overload drop stage. The overload voltage value measured and output by the overload sensor is converted into G1, G2, and G3 changes through analog-to-digital conversion, and then truncated average filtering is performed. The filtered overload digital quantities G1_fit, G2_fit, and G3_fit are compared with the overload zero values ​​GZ_Z1, GZ_Z2, and GZ_Z3 respectively. If the filter value is greater than the overload zero value, the difference between the filter value and the overload zero value is used to eliminate zero drift: G1_fit = G1_fit-GZ_1, G2_fit = G2_fit-GZ_2, and G3_fit = G3_fit-GZ_3; if the filter value is less than or equal to the overload zero value, the filtered overload digital quantity is forced to G1_fit = 0, G2_fit = 0, and G3_fit = 0. Then the difference is compared with the digital threshold 1065 of the target point b relative to the zero position:

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

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

[0229] G3_fit<=1065, accumulate the count of the corresponding channel accumulation 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 meet the cumulative time requirement of 100ms, it is considered that the detection of target point b in the overload descent section is successful.

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

[0235] The parachute opening method can be controlled by combining multiple modes such as "overload + delayed main parachute opening control", "overload + delayed backup parachute opening control" and "pure time backup parachute opening control" to ensure that the parachute opening control can be completed after the overload sensor circuit fails. The "overload + delayed main parachute opening" is designed to precede the "overload + delayed backup parachute opening" and precede the "pure time backup parachute opening control". The specific steps are:

[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 time is solidified in the form of parameters into the parameter list of the recovery control program, and the timing is performed using T1 to T8 registers.

[0246] T1: pure time parachute mode timing register;

[0247] T2: A protection time timing register to prevent the return capsule from separating from the main probe and interfering with overload detection;

[0248] T3: The time timing register of the backup parachute opening mode with the overload ascent stage target point a as the time timing register;

[0249] T4: Time timing register from overload target point a to overload peak value;

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

[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: Pure time 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 in the overload zero drift elimination technical solution. After the calibration is completed, proceed to step 3.

[0255] like Figure 3 As shown, step three: wait for the external input signal "fireworks positive line through", which gives the timing as the time zero of pure time parachute opening T1. When the program reads that the "fireworks positive line through" signal is valid, initialize T1 and T2 registers, start register timing, and enter step ten when the T1 register time reaches the threshold Ta, and enter step four when the T2 register time reaches the threshold Tb.

[0256] Step 4: Detect the overload target point a according to step 3 in the overload zero drift elimination technical solution, and determine whether the T1 register time reaches the threshold Ta. If it reaches it, proceed to step 10. When the overload target point a is detected, proceed to step 5.

[0257] Step 5: Skip the overload peak through time delay and enter the overload drop stage, initialize T3 and T4 registers, start register timing, and determine whether the T1 register time reaches the threshold Ta. If it reaches it, proceed to step ten. When the T3 register time reaches the threshold Tc, proceed to step nine. When the T4 register time reaches the threshold Td, proceed to step six.

[0258] Step 6: Detect the overload target point b according to step 4 in the overload zero drift elimination technical solution, and determine whether the T1 register time reaches the threshold Ta. If it reaches it, proceed to step 10. When the T3 register time reaches the threshold Tc, proceed to step 9. When the overload target point b is detected, proceed to step 7.

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

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

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

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

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

[0264] The contents not described in detail in the specification of the present invention belong to the common knowledge of the professionals in this field.

Claims

1. A highly reliable parachute opening control method for a ballistic entry spacecraft, characterized in that: The following steps are involved: S1, determine the time parameters Ta~Th corresponding to the overload target point and the corresponding T1~T8 registers; S2, power on the recycling control program; S3, perform overload zero position calibration; S4, when receiving an external input instruction, start the timing of the T1 register and the T2 register. When the T1 register reaches the threshold value Ta, enter step S11; when the T2 register time reaches the threshold value Tb, enter step S5; S5, detect the overload target point a, when the T1 register time reaches the time Ta, go to step S11; when the overload target point a is detected and the T1 register time does not reach the time Ta, go to step S6; Otherwise, repeat step S5; S6, start the timing of T3 and T4 registers, and determine whether the T1 register time reaches the time Ta. If so, proceed to step S11; when the T3 register time reaches the time Tc, proceed to step S10; when the T4 register time reaches the time Td, proceed to step S7; S7, perform overload target point b detection to determine whether the T1 register time reaches the time Ta, if so, proceed to step S11; When the T3 register time reaches the time Tc and the overload drop section target point b is detected, the process goes to step S8; when the T3 register time does not reach the time Tc and the overload drop section target point b is detected, the process goes to step S8; When the T3 register time reaches the time Tc and the overload descending section target point b is not detected, the process proceeds to step S10; Otherwise, repeat step S7; S8, start the T5 register timing, determine whether the T1 register time reaches the time Ta, if so, go to step S11; when the T3 register time reaches the time Tc, go to step S10; when the T5 register time reaches the threshold Te, go to step S9; S9, send the command to launch the parachute, and send the command to release the parachute after a delay of Tf through the T6 register; S10, send the command to launch the parachute, and send the command to release the parachute after a delay of Tg through the T7 register; S11, send the command to put the parachute in place, and send the command to take off the parachute after a delay of Th through the T8 register.

2. A high-reliability parachute opening control method for ballistic entry into a spacecraft according to claim 1, characterized in that: The time parameter and the corresponding timing register corresponding to the overload target point are specifically determined as follows: The time parameters corresponding to the overload target point are: Ta: time parameter of pure time parachute opening mode; Tb: protection time parameter to prevent the return capsule from separating from the main probe and interfering with overload detection; Tc: Time parameter for backup parachute opening mode with the target point a in the overload ascent phase; Td: time parameter from overload target point a to overload peak value; Te: time parameter of parachute opening mode with overload descent target point b as the main part; Tf: Overload + delay main parachute opening mode deceleration parachute working time parameter; Tg: Overload + delayed backup parachute opening mode deceleration parachute working time parameter; Th: working time parameter of the deceleration parachute in pure time backup parachute opening mode; The above time is solidified in the parameter form into the recycling control program parameter list, and the time is measured using the T1~T8 registers; T1: pure time parachute mode timing register; T2: A protection time timing register to prevent the return capsule from separating from the main probe and interfering with overload detection; T3: The time timing register of the backup parachute opening mode with the overload ascent stage target point a as the time timing register; T4: Time timing register from overload target point a to overload peak value; T5: Time timing register for the parachute opening mode with the overload descent target point b as the main part; T6: Overload + delay main parachute opening mode deceleration parachute working time timing register; T7: Overload + delayed backup parachute opening mode deceleration parachute working time timing register; T8: Pure time backup parachute opening mode deceleration parachute working time timing register.

3. A high-reliability parachute opening control method for ballistic entry into a spacecraft according to claim 1, characterized in that: The overload zero position calibration is specifically as follows: Calculate the range of the overload sensor zero position output voltage value; Determine whether the zero-position output voltage value of the overload sensor is out of range. If so, prompt the external device to take measures to recover from the fault.

4. A high-reliability parachute opening control method for ballistic entry into a spacecraft according to claim 1, characterized in that: The range of the zero-position output voltage value of the overload sensor is specifically: [(Ref / 2-Vd)×Sens×(2 n -1) / Ref,(Ref / 2+Vu)×Sens×(2 n -1) / Ref] Wherein, Ref / 2 is the theoretical voltage value of the overload zero position, Vd is the maximum lower deviation of the overload sensor zero position drift, Vu is the maximum upper deviation of the overload sensor zero position drift, Sens is the sensitivity of the overload sensor, and n is the effective digital position.

5. A high-reliability parachute opening control method for ballistic entry into a spacecraft according to claim 1, characterized in that: The specific method for detecting the overload target point a is as follows: When GZ_value_fit≥F1, the count value of the corresponding channel accumulation register is accumulated; When GZ_value_fit<F1, the corresponding channel cumulative register count value is cleared; 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 overload digital value after filtering, Ga is the overload value of 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 rising section overload target point a is detected successfully.

6. A high-reliability parachute opening control method for ballistic entry into a spacecraft according to claim 1, characterized in that: The overload target point b detection is specifically as follows: When GZ_value_fit≤F2, the count value of the corresponding channel accumulation register is accumulated; When GZ_value_fit>F2, the corresponding channel cumulative register count value is cleared; 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 drop 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 drop section target point b is detected successfully.

7. A high-reliability parachute opening control method for ballistic entry into a 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; Among them, GZ_value_fit is the overload digital value after filtering; GZ_zero is the overload zero value.

8. A high-reliability parachute opening control method for ballistic entry into a spacecraft according to claim 2, characterized in that: Tb+TTA+Tc>Tb+TTB+Te,Ta>Tb+TTA+Tc+Tg Among them, TTA is the time when the overload target point a is detected; TTB is the time when the overload target point b is detected.

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