JPH0558399A - Rotation period measuring circuit for wheel - Google Patents

Abstract

PURPOSE:To perform measurement through one system of a circuit so as to reduce the number of parts by selecting one of tachopulses for a plurality of wheels and holding and outputting measured data based on a count value after an interval between the tachopulses is measured to provided a count value. CONSTITUTION:Respective tachopulses 1-4 outputted from four wheels are inputted to a tachopulse selecting circuit 11 respectively. Based on a selected signal from a timing regulating circuit 10 to which respective sample timing signals 7 and 8 and a clock 9 for periodic measurement are inputted, a tachopulse intended to be measured is selected to output it to a counter 12. An intervals between a plurality of tachopulses is measured by the counter 12 to output it to a latch circuit 13, a selecting signal load circuit 14, and an overflow processing circuit 15 respectively. Further, the latch circuit 13 holds and outputs measured data for one wheel. The measured data is transmitted to a CPU bus 18 and a telemetry bus 19 through interfaces 16 and 17 respectively.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wheel rotation cycle measuring circuit used for an attitude control actuator of an artificial satellite, and more particularly to a rotation cycle measuring method when there are a plurality of wheels.

[0002]

2. Description of the Related Art At first, only one wheel was used for an actuator for attitude control of a satellite.
A control method using four wheels is under consideration.
In this case, control is performed separately and independently even if there are a plurality of wheels. Therefore, conventionally, for example, as shown in FIG. 2, a rotation cycle measuring method in which a rotation cycle measuring circuit is separately provided for each wheel is adopted. It was

FIG. 2 shows a rotation period measuring method when four wheels are used. Each of the four rotation cycle measurement circuits includes a timing generation circuit 20, a counter 21, a latch circuit 22, a CPU bus interface 23, and a telemetry bus interface 24.

The timing generation circuit 20 of the four rotation cycle measurement circuits is commonly required for the sample timing signal 7 required for the control law calculation in the CPU that controls the four wheels independently and for the telemetry output. The sample timing signal 8 and the period measuring clock 9 are applied, and the reset signal is output to the counter 21 and the latch signal is output to the latch circuit 22, respectively. On the other hand, tacho pulse (1-4)
Is a pulse signal indicating the rotation cycle output from the wheel, which is input to the counter 21 of the corresponding rotation cycle measurement circuit.

The counter 21 includes a timing generation circuit 20.
The interval of the tacho pulse input between the reset signals from is measured, and the measured value is output in the form of a count value of 20 or more bits. The output count value of the counter 21 is held by the latch circuit 22, and the CPU bus interface 23
And via the telemetry bus interface 24 to the CPU bus and the telemetry bus (not shown).

[0006]

However, in the conventional rotation cycle measuring method in which each wheel is measured independently and in parallel, if the number of wheels is about two, there is no problem even if they are formed on one circuit board. However, when the number of units such as 4 units increases, the number of parts increases remarkably, and when it is formed on one circuit board, a large mounting area is required, resulting in an increase in product shape and weight, and an increase in the number of parts. As a result, there is a problem that the cost of parts and the number of manufacturing inspection steps increase. Furthermore, the current consumption of the counter tends to increase when it is operated with a high-speed clock. Therefore, if the counter length is increased to perform measurement with high resolution, the number of counters is increased, which causes a problem of increased power consumption.

An object of the present invention is to provide a wheel rotation cycle measuring circuit which can measure the rotation cycle of each of a plurality of wheels with one circuit without any trouble.

[0008]

In order to achieve the above object, the wheel rotation cycle measuring circuit of the present invention has the following configuration. That is, the wheel rotation cycle measuring circuit of the present invention is a circuit for selectively outputting one tacho pulse of tacho pulses from each of a plurality of wheels used for an attitude control actuator of a satellite according to a selection signal;
A counter that counts the interval between the selected tacho pulses according to a first timing signal; a circuit that adds an identification code that indicates which tacho pulse the output count value of the counter is for; the output count value of the counter is defined A circuit that outputs a flag signal when the value is not within the range; a circuit that holds the output count value of the counter, the identification code, and the flag signal according to a second timing signal, and outputs as measurement data; The selection signal, the identification code, and the first and second timing signals are output in response to each signal of the sample timing required for the control law calculation and the sample timing required for the telemetry output in the CPU that controls independently. Circuit; Sends the measurement data to CPU bus and telemetry bus It is characterized in further comprising a; and CPU bus interface and telemetry bus interface to.

[0009]

Next, the operation of the wheel rotation cycle measuring circuit of the present invention constructed as described above will be described. In the present invention, one tacho pulse is selected from the tacho pulses from each of the plurality of wheels, the interval between the selected tacho pulses is measured, and a count value of a predetermined number of bits is formed. Then, the measurement data obtained by adding the identification code and the flag signal to the count value is held and output to the CPU bus and the telemetry bus. The above operation is time-divisionally performed for all tacho pulses. At this time, the selection signal, the identification code, the first and second
The timing signal of corresponds to the change of the telemetry transfer rate based on each signal of the sample timing required for the control law calculation and the sample timing required for the telemetry output in the CPU that controls the plurality of wheels independently,
In addition, it occurs at the time-division measurement timing in consideration of the simultaneity between the wheels necessary for the attitude control.

Thus, according to the present invention, the rotation cycle of each of a plurality of wheels can be measured in a time-division manner, so that even if a plurality of wheels are used, they can be measured by a single system circuit, and the number of parts is greatly reduced. it can. Therefore, the size and weight of the circuit can be reduced and the power consumption can be reduced.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a wheel rotation cycle measuring circuit according to an embodiment of the present invention. In this embodiment, as in the conventional example, four wheels are mounted. Comparing the components, the tacho pulse selection circuit 11, the selection signal addition circuit 14, and the overflow processing circuit 15 are added to the conventional circuit (one circuit).

However, in the timing adjusting circuit 10, the input signal is the sample timing signal 7 required for CPU control, the sample timing signal 8 required for telemetry output, and the period measuring clock 9, as in the conventional timing generating circuit 20. However, in the present embodiment, the tacho pulse selection circuit 11 and the selection signal addition circuit are adapted to the tacho pulse selection circuit 11 and the selection signal addition circuit at the time-division measurement timing corresponding to the change of the telemetry transfer rate and taking into consideration the simultaneity between the wheels necessary for the attitude control. It generates a selection signal (4 bits), a reset signal for the counter 12 (first timing signal), and a latch signal for the latch circuit 13 (second timing signal). Although the selection signal is used as the identification code in the present embodiment, it may be an independent code signal.

In FIG. 1, tacho pulses 1 to 4 output from four wheels are applied to a tacho pulse selection circuit 11. The tacho pulse selection circuit 11 selects a tacho pulse to be measured according to a selection signal from the timing adjustment circuit 10 and outputs it to the counter 12.

The counter 12 is a timing adjustment circuit 10.
Measure the interval of two or more tacho pulses input during the measurement period between the reset signals from
Latch circuit 13 in the form of a 24-bit count value
Selection signal adding circuit 14 and overflow processing circuit 15
And output to.

At this time, the selection signal adding circuit 14 outputs the selection signal to the latch circuit 13 as information (identification code) indicating which wheel is selected by the selection signal.
On the other hand, when the overflow processing circuit 15 sets the measurement period of one system to twice or more of the maximum period of the measurement range, and only one tacho pulse is input during the measurement period,
Alternatively, a case where no input is made is determined based on the output count value of the counter 12, and when such a case is detected, a flag signal is output to the latch circuit 13.

As a result, the latch circuit 13 holds and outputs the count value, the selection signal and the flag signal as the measurement data for one wheel. This measurement data is CP
It is sent to the CPU bus 18 and the telemetry bus 19 via the U bus interface 16 and the telemetry bus interface 17.

As described above, the measurement for four wheels is repeatedly performed in a time-divisional manner by the measurement circuit of one system.

[0018]

As described above, according to the wheel rotation cycle measuring circuit of the present invention, the rotation cycle of each of a plurality of wheels can be measured in a time-division manner. It can be measured by a circuit, and the number of parts can be reduced significantly. Therefore, there is an effect that the size and weight of the circuit can be reduced and the power consumption can be reduced.

[Brief description of drawings]

FIG. 1 is a configuration block diagram of a wheel rotation period measurement circuit according to an embodiment of the present invention.

FIG. 2 is a configuration block diagram of a conventional wheel rotation period measurement circuit.

[Explanation of symbols]

 10 Timing Adjustment Circuit 11 Tacho Pulse Selection Circuit 12 Counter 13 Latch Circuit 14 Selection Signal Addition Circuit 15 Overflow Processing Circuit 16 CPU Bus Interface 17 Telemetry Bus Interface

Claims (1)

[Claims] 1. A circuit for selectively outputting one tacho pulse among tacho pulses from each of a plurality of wheels used for an attitude control actuator of a satellite according to a selection signal; a first timing signal for the interval between the selected tacho pulses. A circuit for adding an identification code indicating which tacho pulse the output count value of the counter is for; a circuit for outputting a flag signal when the output count value of the counter is not within a specified range A circuit for holding the output count value of the counter, the identification code, and the flag signal in accordance with a second timing signal and outputting them as measurement data; C for independently controlling the plurality of wheels.
A circuit for receiving each signal of a sample timing required for control law calculation in the PU and a sample timing required for telemetry output, and outputting the selection signal, the identification code, and the first and second timing signals; A CPU bus interface and a telemetry bus interface for sending data to the CPU bus and a telemetry bus;
A rotation cycle measuring circuit for a wheel, comprising: