JPH04185598A - Attitude abnormality detecting method in triaxial satellite - Google Patents

Abstract

PURPOSE:To capture the attitude abnormality of an artificial satellite quickly and correctly by loading a calculator where a mathematical model for calculating the predictive ideal value of a wheel is set on a triaxial stable satellite and comparing the rotating frequency of the wheel with the actual rotating frequency of the wheel. CONSTITUTION:A triaxial satellite is constructed so that three wheels 1 disposed on X, Y and Z axes, respectively are controlled to drive by a wheel driving device 2 according to a torque command from a host apparatus. In this case, an artificial satellite is loaded with an on-board calculator 3 for automatically detecting the operational abnormality of the wheels according to a preset mathematical model and outputting an abnormality detecting signal to the host apparatus. The on-board calculator 3 comprises a wheel mathematical model 6 for predicting an ideal value of the rotational frequency of the wheel 1 according to an output of a torque command detecting circuit 4 and an output of a wheel rotational frequency detecting circuit 5, an adder 8 for obtaining a difference between the actual rotational frequency of the wheel 1 and the rotational frequency as a predictive ideal value, and an abnormality judging logic portion 7 for judging the existence of abnormality of the wheel 1.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an attitude abnormality detection method for a three-axis satellite.
In particular, the present invention relates to an attitude anomaly detection method for a three-axis stable satellite that automatically determines anomalies in a three-axis stable satellite using an onboard computer.

[Conventional technology]

Conventionally, wheel abnormality detection in three-axis stabilized satellites is
This was done by using an attitude sensor to detect an abnormal signal output from a single wheel or a disturbance in the attitude of the satellite induced by an abnormality in the wheel.

[Problem to be solved by the invention]

Among the conventional wheel abnormality detection methods mentioned above, those that use the abnormality signal output from a single wheel as a means of abnormality detection are difficult to detect all abnormalities by detecting abnormalities in a single wheel, and the abnormality detection function The drawback is that it cannot respond to abnormalities in itself. Furthermore, the method of detecting a disturbance in posture induced by a wheel abnormality using a posture sensor has the drawback that there is a delay in the time from the occurrence of a wheel abnormality to the detection of the abnormality, making subsequent countermeasures difficult.

[Means to solve the problem]

The attitude abnormality detection method for a three-axis satellite of the present invention is an attitude abnormality detection method for a three-axis satellite that detects an abnormality in the attitude of a three-axis stabilized satellite by detecting an abnormality in the operation of a wheel placed on the three-axis stabilized satellite. The vehicle is configured to include means for determining abnormal operation of the wheel by an on-board calculator based on the torque command applied to drive the wheel via the wheel drive device and the number of rotations of the wheel.

Further, in the attitude abnormality detection method for a three-axis satellite according to the present invention, the determination of wheel operation abnormality by the onboard calculator is based on a mathematical model set including an initial value Ωa(tl) of the wheel rotation speed at time t. The time t obtained based on
The predicted m value Ωc (tz) of the wheel rotation speed at time 2 and the actual wheel rotation speed Ωa (t2) at time t2.
The configuration is such that the determination is made by determining whether or not the difference between the

This example] Next, the present invention will be described with reference to compartments.

FIG. 1 is a block diagram of an example of the present invention. In the practical example shown in Fig. 1, in order to control the spatial attitude of an artificial satellite,
A wheel 1 representing three wheels placed at Y,:lI, a wheel drive device 2 that drives the wheel l in response to an l-lux command from a host device, and a wheel that is installed on the satellite and set in advance. The on-board calculator 3 automatically detects abnormal operation of the wheel 1 using a mathematical model that detects the abnormality, and outputs an abnormal pressure detection signal to the host device in the case of an abnormality, the torque command detection circuit 4 detects the torque command, and the wheel The wheel rotation speed detection circuit 5 is configured to detect the actual rotation speed of the wheel 1 driven by the drive device 2.

The onboard calculator 3 also includes a wheel mathematical model 6 that predicts the ideal value of the rotation speed of the wheel 1 based on the output of the torque command detection circuit 4 and the pressure of the wheel rotation speed detection circuit 5, and a wheel rotation speed detection circuit. Based on the output of the adder 8, which calculates the difference between the actual rotation speed of the wheel I outputted by the wheel mathematical model 5 and the predicted ideal rotation speed of the wheel 1 outputted by the wheel mathematical model 6, The abnormality determination logic section 7 determines whether or not there is an abnormality in the wheel J.

Next, the operation of the actual journey example shown in FIG. 1 will be explained.

The wheel drive device 2 drives the wheel 1 using a given torque command and generates a reaction torque. The tacho pulse applied by the wheel drive device 2 is a pulse signal that generates N pulses per rotation of the wheel 1.
generated by the wheel drive device 2.

The wheel rotation speed detection circuit 5 detects the wheel rotation speed by counting input tacho pulses for a certain period of time (1 second). The relationship between the count value M of the tacho pulses thus detected and the wheel rotation speed Ω (rad/s) is expressed by the following equation (1).

The torque command detection circuit 4 detects a torque command given to the wheel drive device 2 and supplies it to the on-board computer 3.

The wheel mathematical model 6 of the onboard calculator 3 is
This is realized using the above software. In the wheel mathematical model 6, the following equation (2) is calculated using the detected torque command TW and constants related to the wheel given in advance.

TW: Detection of torque applied to the wheel between tl and t2 m (Nm, newton meter) W: Wheel rotor moment of inertia (kgm2) Ωa (tl): Detection at time t1 by wheel rotation speed detection circuit 5 value (ra
d/s) Ωc(tz): The output of the mathematical model 6 of the wheel rotation speed at time t2. Supplied.

The abnormality judgment unit 7 calculates ΩC and Ωa at time t2.
An abnormal signal is output when the difference between the two values becomes larger than a certain predetermined constant value ε as shown in the following equation (3).

〔Effect of the invention〕

As explained above, the present invention is equipped with a calculator that is set up with a mathematical model for calculating the predicted ideal value of the wheel on a three-axis stabilized satellite, and calculates the number of rotations of the wheel and the actual number of rotations of the wheel based on the onboard calculator. By comparing the above, it is possible to automatically, quickly, and reliably detect abnormalities in the wheel and, therefore, in the attitude of the artificial satellite.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention. l...Wheel, 2...-Wheel drive device, 3...On-board computer, 4...Torque command detection circuit, 5...Wheel rotation speed detection Circuit, 6...Wheel mathematical model, 7...Abnormality judgment logic section, 8...Adder. Agent Patent Attorney Susumu Uchihara

Claims (1)

[Scope of Claims] 1. An attitude abnormality detection method for a three-axis satellite, which detects an abnormality in the attitude of a three-axis stabilized satellite by detecting an abnormality in the operation of a wheel disposed on the three-axis stabilized satellite, comprising: a wheel driving device; An attitude abnormality detection method for a three-axis satellite, characterized by comprising means for determining an abnormality in wheel operation by an on-board calculator based on a torque command applied to drive the wheel via the wheel and the number of revolutions of the wheel. 2. The on-board calculator determines whether the wheel is operating abnormally based on the initial value Ωa(of the wheel rotation speed at time t_1).
The difference between the ideal rotational speed Ωc(t_2) of the wheel at time t_2 obtained based on a mathematical model set including t_1) and the actual wheel rotational speed Ωa(t_2) at time t_2 is within a predetermined tolerance range. Claim 1 characterized in that the determination is based on whether or not
Attitude anomaly detection method for the described three-axis satellite.