JPS5843900A - Control system of orbit of triaxial satellite - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] This invention provides that when a three-axis satellite uses a thrust generator (hereinafter referred to as a thruster) to change its orbit, it can continue to maintain a three-wheeled attitude even if there is a problem with the thruster. This paper proposes an orbit control method for three-wheeled satellites.

As a steady-state attitude control method for three-axis satellites.

There is one shown in Figure 1. In the figure, the direction of the z mineral earth,
Y is the direction perpendicular to the orbital plane, xFiy.

2 and axes forming a right-handed orthogonal system, if the orbit is 9 circular, the satellite (
It corresponds to the traveling direction of 1). The rotation angle of the satellite with respect to x, y, and 2 is called an attitude error, and the control of the attitude error of X/2 is called roll/yaw control. The satellite (1) in a steady attitude has an earth sensor (Rin) that detects attitude errors, a magnetic sensor (3) that detects the earth's magnetic field, a pitch wheel (4) as an attitude actuator, a rear wheel (5), and a magnetic sensor. Torca (6) and (71), and attitude control electronic circuit (
8) The three-wheeled attitude is automatically maintained by controlling the attitude by '. When performing orbit control in this steady attitude, it is unavoidable that a large attitude error will occur due to the thruster firing for orbit control. ) is known to make it difficult to recover from a large surface attitude error.

For this reason, conventionally, as shown in FIG.
The control system was switched to one using the eel (4), offset thruster (9), and aO. This control scheme uses an earth sensor (2) to detect attitude errors, and control electronics I to process the attitude errors and generate pitch wheels (4) and offset thrusters (9) and Q (IK control signals). As a result, after reducing the large attitude error caused by the orbit correction 9, for example, the thruster lIe injected to increase the orbital speed, the system returns to the steady attitude control of the first quality at an appropriate time. According to this document, offset thrusters (9
) and α・, as well as a special control electronic circuit Ql), and even if the injection of thruster a2 is stopped due to an attitude error caused by a malfunction of the thruster during orbit correction, the phase change will not occur. There was a lack of safety in that the attitude control had to be continued using the thrusters (9) and personnel.

This was developed in order to eliminate these shortcomings.Attitude control during orbit control can be configured with the same components as those required for steady attitude control shown in Figure 1, and orbit This provides an orbit control system that can maintain a three-axis attitude by simply stopping thruster injection when an attitude error occurs due to a thruster malfunction during correction.

An embodiment of the present invention shown in FIGS. 8 and 4JlK will be described below. FIG. 8 corresponds to FIG. 2 which is a conventional orbit control system, and a control system is constructed using only equipment used for steady attitude control. Since a rear axle gear for roll/yaw control is not used, it is possible to recover from large posture errors. In FIG. 4, (IL (14 is a magnetic control circuit and a magnetic torquer drive path, respectively, a pitch control circuit and a pitch wheel drive circuit, and aη and a are respectively low/
These are a yaw control circuit and a rear wheel drive circuit. In steady state attitude control, these devices perform attitude control.

0 is a trajectory correction command circuit, and an is a thruster drive circuit. ON is related to the orbit correction execution command, and 8W is a switch turned on to cut off the roll/yaw control function. If ON is now commanded, the SW will move to the open state and the roll/field control function will be turned off. At the same time, the propellant valve of the thruster tAs is opened at an appropriate time by the thruster drive circuit (2), and injection for orbit correction is executed. The residual attitude error after the injection is completed is roll/:i1-
It is corrected by steady posture control with the control function removed. Thereafter, when the attitude error becomes sufficiently small, the SW is returned to the closed state to return to steady attitude control. ol) is a safe direction for monitoring the occurrence of attitude errors during trajectory correction, and ga is added if necessary to strengthen the monitoring information of the attitude angular velocity detector, etc. By means of a safe circuit.

When the command is turned OFF when an abnormal attitude error is detected, the thruster drive circuit (1) disconnects the thruster by closing the propellant valve of the thruster wheel.At this time, the remaining attitude error Correction and return to steady attitude control are the same as in the normal trajectory correction described above.

As explained above, according to the present invention, the roll/'i! - A switch for shutting off the control and a safety circuit that disconnects and releases the thruster when an abnormal attitude error is detected, allowing orbit control to be performed without using offset thrusters or special control electronic circuits that were conventionally required. The practical effect is extremely large because safety can be ensured when abnormal posture errors are detected.

In addition, although 9 and above are explained using wheel control consisting of a pitch wheel and a rear wheel, magnetic control using a magnetic sensor, and an earth sensor as an attitude error detector, this invention is not limited to this. It goes without saying that it can be used for devices that have momentum and use wheels to control roll/N-, and the switch that indicates the cutoff of the roll/yaw control function may be inserted wherever that function is performed. If the injection of the orbit correction thrusters is started after the roll/yaw control function is cut off, it is natural that the time elapsed between them can be arbitrarily selected. Additionally, three-axis control by thrusters may be superimposed in attitude control during orbit correction, but this is omitted as it is not essential to the description of this invention.

[Brief explanation of the drawing]

FIG. 1 is a diagram explaining the configuration of steady posture control. FIG. 2 is a diagram for explaining a conventional orbit control method, and FIGS. 8 and 4 are diagrams for explaining an orbit control method according to the present invention. In the figure, (1) is a satellite, (2) is an earth sensor, (3) #N
! (4) is a pitch wheel, (5) is a rear axis wheel, (6) and (7) are magnetic torquers, (
8) is the attitude control electronic circuit, (9) and (lQa offset thruster, aD is the control electronic circuit, aS is the thruster,
aI is a magnetic control circuit, a4 is a magnetic torquer drive circuit, (
1! I is the pitch control circuit, a+9 is the pitch wheel drive circuit, aη is the roll/yaw control circuit, a is the rear axis wheel drive circuit, a is the trajectory correction command circuit, (to)
is the thruster drive circuit, Ql) is the safe circuit, and (2) is '
This is an attitude angular velocity detector, etc. In the drawings, the same or corresponding parts are designated by the same reference numerals. Agent Shin Kuzuno −

Claims (1)

[Claims] An orbit control system for a three-axis satellite that has bias angular momentum in the pitch axis (direction perpendicular to the orbital plane) and that uses wheels to control the attitude of the roll and yaw axes (in the plane perpendicular to the pitch axis). In conjunction with the start of the thrust generator for orbit control, roll /:! - A device is installed to separate the wheel control system, and if the thrust generator malfunctions during orbit control, the thrust generator can be simply disconnected and the drive of the thrust generator for orbit control will be completed normally. A three-axis orbit control method for a three-axis satellite, which is characterized by being able to continue in the same three-axis attitude as in the previous case.