JP2002220097A - Guidance system and acceleration detection device for spacecraft - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a guidance system for a spacecraft that can precisely and shortly compute a thrust acceleration time history in future time during a flight. SOLUTION: The guidance system for a spacecraft comprises an inertia sensor device 1 including an accelerometer for detecting acceleration α of a spacecraft, an inverse number calculating device 2 for calculating the inverse number 1/α of the acceleration, a smoothing device 3 for smoothing the inverse number of the acceleration, and an arithmetic control part for providing guidance control of the spacecraft by using the smoothed inverse number of the acceleration as input information.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spacecraft guidance device and an acceleration detection device, and more particularly to a highly accurate acceleration detection and guidance control by detecting a reciprocal of a thrust acceleration (hereinafter, also simply referred to as "acceleration"). The present invention relates to a spacecraft guidance device and an acceleration detection device that enable the above.

[0002]

2. Description of the Related Art Conventionally, for example, Japanese Patent Application Laid-Open No. 9-5859.
As referred to in Japanese Unexamined Patent Application Publication No. 7-107, a guidance device that issues a control command for a flying object (spacecraft) is well known.

[0003] When guiding a spacecraft, in order to control the motion trajectory of the spacecraft to a desired trajectory with high precision, during flight, the thrust acceleration at a future time until the guidance end time is calculated as a time history. It is required to make predictions in a short time.

In the conventional apparatus described in the above publication,
The thrust acceleration required to guide the flying object to a desired landing point is calculated by a landing control acceleration command generator based on sensor information indicating the position, speed, or acceleration.

[0005] The acceleration command for landing control is sent to a thrust and thrust direction generating unit in the control computer to drive and control the actuator to guide the flying object to a desired trajectory.

[0006] At this time, the acceleration command generation unit does not consider the mass of the flying vehicle during operation and the time change rate of the flying vehicle mass (depending on the specific thrust representing fuel efficiency), and the like, without taking the flying vehicle into landing. The acceleration command at the future time is determined.

That is, since the flying object mass estimating unit of the conventional device estimates the flying vehicle mass using only the thrust command and the thrust direction command as input information, the estimation accuracy of the flying vehicle mass is reduced.

Further, since the thrust command and the thrust direction command are calculated by the product of the acceleration command calculated by the acceleration command generation unit and the estimated value of the vehicle mass, the accuracy is also lowered, which may cause deterioration of the guidance accuracy. Become.

There is also a method of estimating and calculating the mass of the flying vehicle by integrating the flow rate of the consumed fuel and subtracting it from the initial mass of the flying vehicle. In this case, however, a measurement error in the amount of consumed propellant is likely to occur. There is a problem.

Further, according to the above-mentioned method for estimating the mass of the flying object, it is difficult to predict, for example, the amount of the attitude control propellant consumed until the start of landing on the moon. The accuracy of the body mass is also low, which also causes the deterioration of the guidance accuracy.

In general, in a rocket (spacecraft) that flies with a substantially constant thrust, the propellant consumption rate is substantially constant, and the thrust acceleration rapidly increases as the rocket mass decreases at a constant rate.

Therefore, when estimating the thrust acceleration of the spacecraft at a future time during the flight of the spacecraft, it is necessary to use curve fitting as shown in FIG. In FIG. 5, the horizontal axis represents the elapsed time t, the vertical axis represents the acceleration α, the black circles represent past acceleration observation values, and the white circles represent future time acceleration prediction values.

Usually, when a smoothed curve is determined by curve approximation as shown in FIG. 5, three or more unknown parameters are required. Therefore, in a calculation for determining a predicted value, the size of a matrix becomes large. As a result, the calculation time increases, and the determination accuracy also deteriorates as the number of unknown parameters increases.

[0014]

As described above, the conventional spacecraft guidance system can provide an acceleration command at a future time until the spacecraft guidance is completed without considering the mass of the vehicle or its time change rate. Since it is determined, there is a problem that the mass of the flying object and its time rate of change are easily affected by errors from the design values, and the guidance accuracy is deteriorated.

A conventional spacecraft acceleration detecting device includes:
Since the acceleration detection value having the characteristic curve of FIG. 5 is output as it is, a curve fitting is required for the acceleration prediction calculation processing at a future time, and the calculation load increases.
As a result, there is a problem that the prediction accuracy of the thrust acceleration time history is deteriorated.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and is directed to a spacecraft guidance system capable of calculating a thrust acceleration time history at a future time with high accuracy and in a short time during flight. The aim is to obtain a device.

It is another object of the present invention to provide a spacecraft acceleration detecting device capable of detecting a thrust acceleration time history at a future time during flight with high accuracy.

[0018]

A spacecraft guidance apparatus according to a first aspect of the present invention includes an inertial sensor device including an accelerometer for detecting the acceleration of a spacecraft, and a reciprocal calculation for calculating a reciprocal of the acceleration. The apparatus comprises a device, a smoother for smoothing the reciprocal of acceleration, and an arithmetic control unit for performing guidance control of the spacecraft using the reciprocal of the smoothed processing as input information.

According to a second aspect of the present invention, there is provided a guidance device for a spacecraft according to the first aspect, further comprising a predictor inserted between the smoother and the arithmetic and control unit, wherein the predictor performs a smoothing process after the smoothing process. The reciprocal of the future time prediction acceleration is calculated from the reciprocal of the acceleration of (i), and the arithmetic control unit uses the reciprocal of the future time prediction acceleration as input information.

According to a third aspect of the present invention, there is provided the guidance apparatus for a spacecraft according to the first or second aspect, wherein the arithmetic control unit performs an arithmetic operation for controlling the spacecraft based on the input information. A control computer, an induction computer and an actuator that drives the spacecraft in response to the calculation results of the control computer, the induction computer calculates an acceleration direction command value of the spacecraft based on the input information, The acceleration command value for the actuator is calculated in response to the acceleration direction command value.

According to a fourth aspect of the present invention, in the spacecraft guidance device according to the third aspect, the arithmetic control unit includes a second reciprocal calculation device for calculating the reciprocal of the input information.

According to a fifth aspect of the present invention, there is provided an acceleration detecting device for a spacecraft, comprising: an inertial sensor device including an accelerometer for detecting the acceleration of the spacecraft; a reciprocal calculating device for calculating a reciprocal of the acceleration; And a smoother for smoothing the reciprocal of the acceleration.

According to a sixth aspect of the present invention, there is provided an acceleration detecting apparatus for a spacecraft according to the fifth aspect, further comprising a predictor for calculating a reciprocal of a future time prediction acceleration from a reciprocal of the smoothed acceleration. Things.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 Hereinafter, Embodiment 1 of the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram showing a spacecraft guidance apparatus according to Embodiment 1 of the present invention, and typically shows an acceleration detection unit.

In FIG. 1, reference numeral 1 denotes an inertial sensor device including an accelerometer for detecting an acceleration α of a spacecraft (not shown). Reference numeral 2 denotes a reciprocal calculator for calculating the reciprocal 1 / α of the acceleration α, and reference numeral 3 denotes a smoother for smoothing the reciprocal 1 / α of the acceleration α.

Although not shown in FIG. 1, an arithmetic control unit including a microcomputer is connected to the smoothing unit 3. The arithmetic control unit controls the guidance of the spacecraft using the reciprocal 1 / α of the acceleration smoothed by the smoothing unit 3 as input information.

As shown in FIG. 1, the acceleration α measured by the accelerometer in the inertial sensor device 1 is calculated by a reciprocal calculation device 2
And the reciprocal 1 / α of the acceleration is calculated. Also,
The smoother 3 calculates a smoothed value of the reciprocal 1 / α of the acceleration obtained every moment, and inputs the calculated smoothed value to the arithmetic control unit.

In the smoothing process calculation by the smoothing unit 3, an operation of plotting the reciprocal 1 / α of the momentarily obtained acceleration with respect to the elapsed time t as shown in FIG. 2 and approximating the time change with a straight line is performed. That is.

FIG. 2 is a characteristic diagram showing a linear approximation of the reciprocal 1 / α of the acceleration by the smoothing calculation process. In FIG. 2, the horizontal axis represents the elapsed time t, the vertical axis represents the reciprocal of the acceleration 1 / α, the black circle represents the reciprocal of the past measured value of the acceleration, and the white circle represents the reciprocal of the predicted acceleration value of the future time.

The reciprocal calculator 2 calculates the reciprocal 1 / α of the acceleration from the accelerations observed in the past, and the smoother 3 uses the fact that the reciprocal 1 / α of the acceleration can be represented by a linear function of the elapsed time t. Then, two coefficients of the linear function are estimated and calculated from the time history of the reciprocal 1 / α of the acceleration.

As will be described later, the arithmetic and control unit includes a guidance computer for calculating a desired trajectory of the spacecraft and a control computer for actually driving the spacecraft via an actuator. The guidance calculation and the control calculation are performed using the time history of the reciprocal of α, and the actuator is driven to change the trajectory of the spacecraft, and the spacecraft is put into a desired trajectory.

In determining a straight line (linear function) as shown in FIG. 2, unlike the case of the curve (see FIG. 5), there are two unknown parameters (the slope of the straight line and the intercept with respect to the vertical axis).
It is reduced as compared with the case of the conventional device using the curve fitting.

That is, the reciprocal 1 of the acceleration by the smoother 3
In the smoothing process of / α, the problem of the straight line approximation is solved, and the calculation can be performed in a shorter operation time than in the case of solving the problem of the curve approximation.

Therefore, as the number of unknown parameters is reduced, the approximate calculation time for a linear function is reduced, and
The determination accuracy is also improved, and the reciprocal 1 / α of the acceleration can be accurately approximated as a linear function of the elapsed time t.

As described above, the reciprocal of the thrust acceleration value at the future time (future time prediction acceleration) is calculated by a simple linear approximation by using the reciprocal 1 / α of the acceleration as an input to the smoother 3. The load on the arithmetic and control unit during the flight is reduced, and the future time predicted acceleration including the error component such as the specific thrust can be acquired with high accuracy.

As a result, the spacecraft can be guided to the designated space using the thrust acceleration at the future time with high accuracy.

Embodiment 2 In the first embodiment, the processing information of the smoothing unit 3 is used as input information of the arithmetic control unit as it is. However, the predicting unit 4 may be interposed as shown in FIG.

FIG. 3 is a block diagram showing a spacecraft guidance apparatus according to a second embodiment of the present invention.
The same reference numerals are given to the same components, and the detailed description is omitted.

In FIG. 3, reference numeral 4 denotes a predictor inserted between the smoother 3 and the arithmetic control unit. The predictor 4 calculates the reciprocal of the future time predicted acceleration from the reciprocal 1 / α of the smoothed acceleration. Is calculated, and this is used as input information to the arithmetic control unit.

The predictor 4 shown in FIG. 3 calculates the time history of the reciprocal of the predicted future time acceleration based on the reciprocal 1 / α of the acceleration smoothed by the smoother 3. That is, the reciprocal of the predicted future time acceleration is calculated using the approximate straight line described above (see FIG. 2), and this is used as input information to the arithmetic control unit.

In this case as well, the accuracy of determining the approximate straight line (see FIG. 2) is higher than the accuracy of the approximate curve (see FIG. 5), as described above. Accuracy also improves.

As described above, the reciprocal of the acceleration after the smoothing process is 1
By inputting / α to the predictor 4, the reciprocal of the future time predicted acceleration is subjected to prediction calculation processing as extrapolation of a straight line having the elapsed time t as an independent variable.

Therefore, the reciprocal of the future time predicted acceleration can be calculated with a shorter calculation time and a smaller prediction error than in the case of the conventional device in which the acceleration at the future time is predicted and calculated as an extrapolation of a curve.

Embodiment 3 FIG. In the first embodiment,
In FIG. 2, the specific functional configuration of the arithmetic control unit is not shown, but may be configured as shown in FIG.

FIG. 4 is a block diagram showing a spacecraft guidance apparatus according to Embodiment 3 of the present invention. Components similar to those described above (see FIG. 1 and FIG. 3) are designated by the same reference numerals. The description is omitted.

In FIG. 4, the arithmetic control unit includes a second reciprocal calculator 22 (hereinafter, simply referred to as a “reciprocal calculator”).
, A guidance computer 5 and a control computer 6, an actuator 7, and a spacecraft dynamics 8.

The second reciprocal calculator 22 further calculates the reciprocal of the input information (reciprocal of the predicted future time acceleration) to calculate the predicted future time acceleration. The guidance computer 5 and the control computer 6 perform control operations for the spacecraft based on the input information (future time prediction acceleration) via the second reciprocal calculation device 22.

That is, the guidance computer 5 calculates the acceleration direction command value C of the spacecraft based on the predicted future time acceleration, and the control computer 6 calculates the acceleration command value D for the actuator 7 based on the acceleration direction command value C. calculate.

The actuator 7 is driven and controlled in response to the calculation results (acceleration command value D) of the guidance computer 5 and the control computer 6, and gives a thrust F to the spacecraft dynamics 8 to drive the spacecraft.

The spacecraft dynamics 8 gives a desired acceleration to the spacecraft, and forms a feedback control loop via the inertial sensor device 1 integrated with the spacecraft together with the above configuration.

As shown in FIG. 4, the acceleration detecting device including the inertial sensor device 1, the reciprocal calculating device 2, the smoothing device 3, and the predictor 4 inputs the reciprocal of the future time predicted acceleration to the arithmetic control unit.

The reciprocal calculation device 22 in the arithmetic control unit calculates the future time predicted acceleration from the input information (reciprocal of the predicted future time acceleration) and inputs the calculated acceleration to the guidance computer 5. Guidance calculator 5
Calculates the acceleration direction command value C over the future time from the future time predicted acceleration according to a guidance rule such as the bilinear tangent rule.

The control computer 6 calculates an actuator command value D based on the acceleration direction command value C obtained from the guidance computer 5 and inputs the same to the actuator 7. As a result, the actuator 7 is driven and the acceleration direction command value C
Is generated, and the spacecraft moves according to the spacecraft dynamics 8.

The acceleration due to the movement of the spacecraft is measured by an inertial sensor device 1 including an accelerometer.

At this time, the guidance computer 5 and the control computer 6 use the highly accurate future time prediction acceleration, for example, according to the bilinear tangent rule described above to obtain the acceleration direction command value C.
To determine.

Therefore, even when the actual operation state (for example, specific thrust, initial spacecraft mass, and substantially constant thrust) includes an error from the design value, high-precision guidance in accordance with the actual operation state is realized. Can be.

Embodiment 4 FIG. In the third embodiment, the reciprocal calculator 22 is provided in the arithmetic control unit, but the reciprocal calculator 22 may be omitted.

Also in this case, the guidance computer 5 and the control computer 6 perform the guidance calculation and the control calculation by using the time history of the reciprocal of the future time prediction acceleration, and drive the actuator 7 to change the trajectory of the spacecraft. The spacecraft can be put into a desired orbit.

Therefore, as described above, even if the operation state is different from the operation state of the design value, the guidance command 6 uses the future time prediction acceleration based on the input information corresponding to the actual operation state. D can be calculated,
It is possible to realize guidance with higher accuracy than when the acceleration command value D is calculated using the operation state of the design value as input information as in the conventional device.

Embodiment 5 FIG. In addition, the first embodiment
In FIG. 4, although the description has been made focusing on the guidance device of the spacecraft, even when focusing only on the acceleration detecting device of the spacecraft, the provision of the reciprocal calculation device 2 makes it possible to acquire high-accuracy acceleration information. It goes without saying that the same operation and effect as described above can be obtained.

[0061]

As described above, according to the first aspect of the present invention, an inertial sensor device including an accelerometer for detecting the acceleration of a spacecraft, a reciprocal calculating device for calculating a reciprocal of the acceleration, And a calculation control unit for controlling the guidance of the spacecraft using the reciprocal of the smoothed acceleration as input information, so that the thrust acceleration time history at a future time during flight is provided. There is an effect that a guidance device for a spacecraft which can calculate the with high accuracy in a short time can be obtained.

According to a second aspect of the present invention, in the first aspect, there is provided a predictor inserted between the smoother and the arithmetic and control unit, wherein the predictor calculates the inverse of the smoothed acceleration. The reciprocal of the future time prediction acceleration is calculated, and the arithmetic control unit calculates
Since the reciprocal of the future time prediction acceleration is used as input information, there is an effect that a spacecraft guidance device that can calculate the thrust acceleration time history at the future time with high accuracy and in a short time during flight is obtained.

According to a third aspect of the present invention, in the first or second aspect, the arithmetic and control unit comprises: a guidance computer and a control computer for performing a calculation for controlling the spacecraft based on the input information; An actuator that drives the spacecraft in response to a calculation result of the computer and the control computer,
The guidance computer calculates the acceleration direction command value of the spacecraft based on the input information, and the control computer calculates the acceleration command value for the actuator in response to the acceleration direction command value. There is an effect that a spacecraft guidance device capable of calculating a thrust acceleration time history at a time with high accuracy and in a short time is obtained.

According to a fourth aspect of the present invention, in the third aspect, the arithmetic control unit includes the second reciprocal calculating device for calculating the reciprocal of the input information, so that the calculation control unit can calculate the reciprocal of the input information at a future time during the flight. The thrust acceleration time history can be calculated with high accuracy and in a short time.

According to a fifth aspect of the present invention, an inertial sensor device including an accelerometer for detecting the acceleration of the spacecraft, a reciprocal calculating device for calculating a reciprocal of the acceleration, and a smoothing process for the reciprocal of the acceleration With this configuration, there is provided an effect that an acceleration detection device for a spacecraft capable of detecting a thrust acceleration time history at a future time with high accuracy during flight is obtained.

According to a sixth aspect of the present invention, in the fifth aspect, a predictor for calculating the reciprocal of the future time predicted acceleration from the reciprocal of the smoothed acceleration is provided. There is an effect that an acceleration detection device for a spacecraft that can detect a thrust acceleration time history at a time with high accuracy is obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an acceleration detection unit of a guidance device for a spacecraft according to Embodiment 1 of the present invention.

FIG. 2 is a characteristic diagram showing a reciprocal of an acceleration obtained according to the first embodiment of the present invention.

FIG. 3 is a block diagram showing an acceleration detection unit of a guidance device for a spacecraft according to Embodiment 2 of the present invention.

FIG. 4 is a block diagram showing a guidance device for a spacecraft according to a third embodiment of the present invention.

FIG. 5 is a characteristic diagram showing acceleration obtained by a conventional spacecraft guidance device.

[Explanation of symbols]

1 inertial sensor device, 2 reciprocal calculation device, 3 smoother,
4 Predictor, 5 guidance computer, 6 control computer, 7 actuator, 22 second reciprocal calculator, C acceleration direction command value, D acceleration command value, F thrust, α acceleration,
1 / α Reciprocal of acceleration.

Claims (6)

[Claims] An inertial sensor device including an accelerometer for detecting an acceleration of the spacecraft; a reciprocal calculating device for calculating a reciprocal of the acceleration; a smoother for performing a smoothing process on the reciprocal of the acceleration; And a calculation control unit for performing guidance control of the spacecraft using the reciprocal of the acceleration as input information. 2. A predictor inserted between the smoother and the arithmetic control unit, wherein the predictor calculates a reciprocal of a future time prediction acceleration from a reciprocal of the acceleration after the smoothing process, The guidance device for a spacecraft according to claim 1, wherein the arithmetic control unit uses the reciprocal of the future time prediction acceleration as the input information. 3. An induction computer and a control computer for performing an operation for controlling the spacecraft based on the input information, and the operation control unit includes: an induction computer and a control computer, wherein the spacecraft is responsive to an operation result of the induction computer and the control computer. An actuator that drives the spacecraft, the guidance computer calculates an acceleration direction command value of the spacecraft based on the input information, and the control computer responds to the acceleration direction command value,
The guidance device for a spacecraft according to claim 1, wherein an acceleration command value for the actuator is calculated. 4. The guidance device for a spacecraft according to claim 3, wherein the arithmetic control unit includes a second reciprocal calculator for calculating a reciprocal of the input information. 5. A space comprising: an inertial sensor device including an accelerometer for detecting acceleration of a spacecraft; a reciprocal calculating device for calculating a reciprocal of the acceleration; and a smoother for smoothing the reciprocal of the acceleration. Machine acceleration detector. 6. The acceleration detection device for a spacecraft according to claim 5, further comprising a predictor for calculating a reciprocal of a future time prediction acceleration from the reciprocal of the acceleration after the smoothing process.