JPH0830712B2 - Exponential average wind vane - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention is used for an instrument for measuring a wind direction. In particular, the present invention relates to a calculation means for determining the wind direction based on the exponential average wind direction.

〔Overview〕

The present invention, in the exponential average anemometer for determining the wind direction based on the input value indicating the wind direction instantaneous value, by performing the index averaging operation using the angle value extracted from the table based on the input value indicating the wind direction instantaneous value, It is possible to determine the wind direction in a short processing time by avoiding repetition of exponential averaging and omitting calculation of a complex arctangent value by a calculation algorithm.

[Conventional technology]

In the conventional example, the exponential average value of each of the sine component and the cosine component of the instantaneous wind direction input value is obtained, and the arctangent value of the sine value calculated based on this value is further exponentially averaged to determine the exponential average value wind direction. are doing.

[Problems to be solved by the invention]

In such a conventional example, the exponential averaging operation is repeatedly performed, and moreover, the calculation algorithm needs to calculate a complex arctangent value, so that the processing time of the CPU becomes long, and therefore, the input processing with a short sampling cycle is performed. Has the drawback of requiring a computer with high speed computing power.

The present invention eliminates such drawbacks, and an object of the present invention is to provide an exponential average wind vane capable of determining the average wind direction with a simple calculation algorithm.

[Means for solving the problem]

The present invention is an exponential average wind vane that determines a wind direction based on an input value indicating an instantaneous wind direction, and an angle of 0 ° to 36 °
The range of 0 ° is divided into divisions corresponding to the resolution of the input value, and the data table in which the angle values representing this division are assigned to each division is stored. ROM that can be accessed with and this ROM
The absolute angle calculation means for calculating the absolute angle difference corresponding to this angle value by referring to the value of the angle difference between the angle value accessed from An exponential average calculating means for calculating an exponential average value with respect to the obtained absolute angle and an azimuth converting means for converting the exponential average value calculated by the exponential average calculating means into a wind direction.

[Action]

The angle value registered in the data table is extracted based on the input value indicating the wind direction instantaneous value. It is determined whether or not the difference between the current value and the average value up to the previous time is 180 ° or more, the absolute angle difference is calculated based on the result of this determination, and then the exponential average calculation is performed. When this calculated value is 360 ° or more, 360 ° is subtracted and this exponential average calculated value is associated with the bearing name. For example, to associate with 16 bearings, add 11.25 ° and add 22.5
If the anonymous number divided by ° is within a predetermined range, the direction name corresponding to this range is used as the direction name for this exponential average calculation value.

In this process, repetition of exponential averaging is avoided and calculation of arctangent value, which is complicated in the calculation algorithm, is omitted, so that the wind direction name can be determined in a short processing time.

〔Example〕

 An embodiment of the present invention will be described below with reference to the drawings.

First, the structure of this embodiment will be described with reference to FIGS. In this embodiment, as shown in FIG.
To 360 °, the range is divided into sections corresponding to the resolution of the input value indicating the wind direction instantaneous value, the angle values representing the sections are assigned to the respective sections, and the angle values representing this section are assigned. Refer to the value of the angle difference between the ROM1 that stores the data table 11 that can be accessed with the input value and the angle value accessed from this ROM1 and the exponential average angle value for the input value up to the previous time, and the absolute value equivalent to this angle value. Absolute angle calculation means 2 for calculating the angle difference, and exponential average calculation means 3 for calculating the exponential average value for the absolute angle obtained by this means.
And an azimuth conversion means 4 for converting the exponential average value calculated by this means into an azimuth.

 Next, the operation of this embodiment will be described.

The input value from the sensing unit that detects the instantaneous value of the wind direction is 2 ⁿ types (n is
It is digitized into a code of the number of pairs of photo couplers and becomes a gray code. In the ROM1, the data table 11 is accessed based on this Gray code and the angle value corresponding to this input value is extracted. The absolute angle calculation means 2 calculates the angle difference between the exponential average angle value for the previous input value and the angle value extracted from the data table 11 for the current input value (step S1). If it is less than 180 °, set the plus flag (step S5),
When the angle is 180 ° or more, the minus flag is set (step S3), and when the plus flag is set, when the angle difference is −180 ° or less, the value obtained by adding 360 ° to this angle difference is the absolute angle. Difference (step S7), and when the angle difference exceeds −180 °, this angle difference is used as the absolute angle difference (step S8). Also, with the minus flag set, the angle difference from 360 ° The value obtained by subtracting is the absolute angle difference (step S4). Exponential averaging means 3
Substitutes this absolute angle difference into the equation (1) to calculate the exponential average angle value (step S9). Here, as the operation sign ± that connects the first term and the second term on the right side of this expression, the sign + is selected when the plus flag is set, and the sign − when the minus flag is set. Is selected.

Y _n = Y _n-1 ± Y _d (1-ε ^{-t / T} ) (1) where Y _n : average value [°] Y _n-1 : previous average value [°] Y _d : absolute Angle difference [°] ε: Base of natural logarithm (= 2.71828 ...) T: Time constant t: Data update interval Next, in the azimuth conversion means 4, the exponential average angle value calculated by the exponential average calculation means 3 is 360 °. When it is above, the output value is the value obtained by subtracting 360 ° from this exponential average angle value (step S11). When it is less than 360 °, this exponential average angle value is used as the output value, and the exponential average angle value is negative. Value of this exponential average angle value is added as the output value (steps S12 and S13), and when this exponential average angle value is a positive value or 0 °, this exponential average angle value is As the output value (step S12), and then add 1 to this output value.
The azimuth name corresponding to the numerical value obtained by adding 1.5 ° and dividing by 22.5 ° is selected from 16 azimuths (step S15).

In this embodiment, the case of 16 azimuth names has been described, but the present invention can be implemented even when applied to another azimuth name system including 32 azimuth names.

〔The invention's effect〕

As described above, according to the present invention, the angle as a representative value is tabulated without dividing the input value into the sine component and the cosine component, and the exponential averaging operation is performed using this value. This is one time less than in the conventional example, and since the time-consuming arctangent calculation, which is performed in the conventional example, is not performed, the average processing time can be significantly shortened.

[Brief description of drawings]

FIG. 1 is a block diagram showing the overall configuration of the embodiment of the present invention. FIG. 2 is a flowchart showing the processing of the embodiment of the present invention. 1 ... ROM, 2 ... absolute angle calculation means, 3 ... exponential average calculation means, 4 ... direction conversion means, 11 ... data table.

Claims (1)

[Claims] 1. In an exponential average anemometer for determining a wind direction based on an input value indicating an instantaneous wind direction value, an angle range of 0 ° to 360 ° is divided into sections corresponding to the resolution of the input value. Stores a data table in which representative angle values are assigned to each category,
Corresponding to this angle value by referring to the ROM that can access the angle value that represents this category with the above input value, and the angle difference value between the angle value accessed from this ROM and the exponential average angle value for the previous input value The absolute angle calculation means for calculating the absolute angle difference of, the exponential average calculation means for calculating the exponential average value for the absolute angle obtained by this absolute angle calculation means, and the exponential average value calculated by this exponential average calculation means An exponential average wind vane, comprising: an azimuth converting means for converting the wind direction.