JPS6029885B2 - weight measuring device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a weight measuring device that can be used on a vibrating body with a relatively long vibration period, which has been difficult in the past.

Conventionally, when trying to measure the weight of an object on a vibrating body that oscillates with a relatively long period, the measurement time is set to an integral multiple of the oscillation period in order to eliminate the influence of the vibration mixed into the measured value. There is a method of determining the weight using the average value of many measured values, and a method of determining the weight using the average value of many measured values. It would have been better to divide the output of the correction load converter by the output of the correction load converter to eliminate unnecessary vibration components.

In the former method of determining the average value, it is necessary to increase the measurement time in proportion to the vibration period, which limits its use.

For example, as shown in Fig. 1, if an object to be measured (including a tare) of mass M is measured by a vibration accelerometer Q in the vertical direction (indicated by the arrow), on an object that vibrates at an angular frequency. , the gravitational acceleration is g, the initial phase is 8, and the average value e of the output of the load converter 2 for T seconds is expressed by the formula m.

Here, for the sake of simplification, assuming that 0=0 and considering the error Er with respect to the true value, the following equation is obtained.

Er=e-Mg=hand; MQSin's tdt: main-MQ
-Sai(・-■T of S)--...-'2} (2} From the formula, the error Er is a coefficient inversely proportional to the time T, and T=(yo-1)m
It is shown as the product of the function in the bracket that takes the maximum value 2.

Assuming that a constant error is Er, the time T' required for the average value to fall within this error Er can be expressed by equation '3).

However, for the sake of simplicity, it is assumed that the function in parentheses has a maximum value of 2. T'3. MQ・Poison...Glue If we take weight measurement on a ship as an example, which is one of the applications of this type of device, the vertical vibration acceleration Q=0.2, the angular frequency = 2 x busy x 0.1 (day 2), and assuming that the measurement error due to vibration acceleration in the vertical direction is allowed up to 1/200, the previous error Er, = red/M Yu, {31 formula 'When entering, T' = machine XM〇. 2nd evening.

2zuX〇. ,≠127 fields. ．．・・・． ...{4},
This method of determining weight from the average value requires a very long measurement time and is not practical.

Further, when measuring the quantity by dividing the latter output e of the weighing load converter by the output e2 of the correction load converter, tare correction of the weighing load converter is not performed as described below.
There was a drawback that a constant value was output even when the weight was zero. For example, as shown in Fig. 2, when an object to be measured (not including a tare) 1' with a weighing force of M' is weighed by a weighing load converter 2' with a tare 3 weighing m, the output e, is {5
-The result is shown in the formula.

e, :K, (M'+m,) (evening ±Q) ...{5
1. However, the gravitational acceleration, Q', the vibration acceleration in the vertical direction, and K are proportional constants between the amount of load applied to the weighing load converter and the electrical output.

Similarly, when the sum of the correction weight of the correction load converter 4 and the weight of the related tare is set aside, the output e2 of the correction load converter 4 is expressed by equation (2).

e2=K2m2(multi±Q)...(6}
However, evening and Q are the same values as in formula [5}.

In FIG. 2, 5 is a correction weight and tare, 6 is a divider, and 7 is a display section. When the same equation is divided by equation {6), it can be seen that an unnecessary output corresponding to the weight ml of the tare bag 3 remains, as shown in equation '7).

e1K1M'10m1) (evening + Q)Ksa;2 (M+m.)
e2 K2. m2. (Evening±Q). ...--[7] Generally, the weight m of the tare bag 3 is about 10 to 20% of the maximum weighing weight, and in some cases it can be more than this, so it is impossible to ignore it. Therefore, this method has the disadvantage that weight measurement cannot be carried out on a ship.

The present invention has been made to solve the above-mentioned drawbacks, and its purpose is to quickly measure the weight of a sliding object to be measured with a simple structure, and to accurately eliminate the influence of the tare weight of a weighing transducer. It is an object of the present invention to provide a weight measuring device which can perform highly accurate measurement by correcting the weight.

That is, in order to achieve the above object, the present invention has the following features:
A weight measuring device used on a swinging object includes a weighing load transducer that receives the weight of an object to be measured and a tare for weighing in a sensitivity direction and outputs an electric signal corresponding to the weight, and a weighing load transducer that receives the weight of an object to be measured and a tare for weighing in a direction of sensitivity, and outputs an electric signal corresponding to the weight of the object to be measured and a tare for weighing. It is installed near the weighing load converter so as to be in the same direction as the sensitivity direction of the converter, and receives the weight of the weight for swing acceleration correction and the tare weight in the sensitivity direction, and generates an electric signal corresponding to the weight. a first amplifier that amplifies the electric signal output from the weighing load converter; and a second amplifier that amplifies the electric signal output from the correction load converter. and,
a subtracter that receives the output of the first amplifier and the output of the second amplifier and calculates the output difference; and a subtracter that divides the output difference from the subtracter by the output of the second amplifier; a divider that outputs an electrical signal corresponding to the weight of the object to be measured, and an electrical output corresponding to the weight of the weighing tare included in the output of the two load converters, and the correction weight and the weight. The gain of the first amplifier or the second amplifier is set so that the electrical output corresponding to the weight of the tare bag is equal. Third
The figure shows an embodiment of the present invention, where A is a weight detection section, B is a calculation section, 1' is an object to be measured with a weight of M' (not including a tare), and 2' is a weighing load converter. , 3 is a weighing tare (hereinafter simply referred to as tare) of the weighing load converter 2'.

Weight m, 4 is a bucket load converter, 5 is a correction weight and a tare weight (hereinafter simply referred to as a tare. Weight m2), 8 is a first amplifier (hereinafter simply referred to as an amplifier), 9 is a second amplifier (hereinafter simply referred to as an amplifier), 9 is a subtracter, 1/divider, and 11 is a display section. The principle of the present invention will be explained below with reference to FIG. 3, taking weight measurement on a ship as an example.

Now let the gravitational acceleration be the acceleration, and the vibration acceleration in the vertical direction (±Q
) When there is a weight measuring device shown in FIG. 3 on a ship vibrating at the angle of [ Same as Type 5'
8} is shown by the formula. e, = K, (M'+m,) (evening ± Q
)...{8} In addition, the electrical output e2 of the correction load converter 4, which has the same sensitivity direction as the weighing load converter 2' and is placed near it, is the same as the gravitational acceleration and the vertical direction. Since the gravitational acceleration ±Q can be considered to be the same value as that of the weighing load converter 2', it is expressed by the equation (9) similarly to the equation (6).

e2=K2m2 (evening ±Q) ...{9'Next, the output e of the weighing load converter 2' and the output e2 of the correction load converter 4 are connected to the amplifier 8 and the amplifier ~ with amplification degree A, respectively. After amplification by amplifier 8', these outputs e,'=A
, e, , e2' and =Agi2 are subtracted in the subtracter 9, resulting in a working equation.

e,'-e2'= {K, A, (M+m,)-K2A2
m2} (evening ±Q) ...'I
Q After that, when this (e,'-e2') is set in the divider 10' and divided by the output e2' of the correction load converter 4, equation (11) is obtained.

e,'-e2' K, A, (M'+m,)-K2mm2
．． ．． ．． ．． ．． ．． oye2' - K2 mm2 Here, the weight of the tare 3 contained in the output e, e2 of both load converters, m, and the weight of the correction weight and the tare 5 r2
If the gain of amplifier 8 or amplifier 8' is adjusted so that the electrical outputs corresponding to are equal, then K, A, m, = K2
As a result, as shown in equation (12), unnecessary vibration components are eliminated, and weighing becomes accurate in an extremely short time, without even including the influence of the tare component of the weighing load converter. This results in an output proportional to .

Kiji = obi X device M.・・・． (12) As explained above, the weight measuring device of the present invention includes a weighing load converter, a correction load converter, a correction weight, a first amplifier, a second amplifier, a subtracter, and a divider. It has a simple configuration with basic components, and there is no need to adjust the amplifier gain depending on the weight of the object to be measured.
The weighing converter has a simple circuit configuration, does not require the use of circuit elements that tend to deteriorate over time, and can measure the weight of an object to be measured on a vibrating body with a relatively long period in an extremely short time, which was previously difficult. It is possible to accurately correct the influence of tare weight on a ship and measure it with high precision.In the above, we have explained weight measurement on a rocking ship, but for example, on a rocking bridge, elevated road, or on a vibration source. It is also possible to measure weight on adjacent soft ground, on a moving vehicle, etc.

Furthermore, since the weight measuring device of the present invention automatically corrects for changes in gravitational acceleration, it can be easily applied as a mass meter.

[Brief explanation of the drawing]

Figure 1a is a block diagram showing an example of the configuration of a conventional weight measuring device, and Figure 1b shows the relationship between the output of the load converter and time when measured with the weight measuring device shown in Figure 1a. figure,
Fig. 2a is a block diagram showing another example of the configuration of a conventional weight measuring device, and Fig. 2b shows the output of the load converter and the output of the divider when measured with the weight measuring device of Fig. 2a. Figure 3a is a block diagram showing the configuration of an embodiment of the present invention, Figure 3b is a diagram showing the relationship with time, and Figure 3b is the output of the load transducer when measured with the weight measuring device of Figure 3a. FIG. 3 is a diagram showing the relationship between the output of a divider and time. 1...Object to be measured (including tare), 1'...Object to be measured (excluding tare), 2...Load converter, 2'...Weighing load converter, 3...Tare, 4 ...Correction load converter,
5... Correction weight and tare, 6... Divider, 7.
...Display, 8, 8'...Amplifier, 9...Subtractor,
10...Divider, 11...Display device. Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] 1. In a weight measuring device used on a swinging object,
a weighing load transducer that receives the weight of the object to be measured and a tare for weighing in a sensitivity direction and outputs an electric signal corresponding to the weight; a correction load converter that is installed near the weighing load converter, receives the weight of a weight for swing acceleration correction and a tare weight in the sensitivity direction, and outputs an electric signal corresponding to the weight; a first amplifier that amplifies the electrical signal output from the converter; a second amplifier that amplifies the electrical signal output from the correction load converter; and an output of the first amplifier and the second amplifier. a subtracter that receives the output of the amplifier and calculates the output difference; and divides the output difference from the subtracter by the output of the second amplifier, and outputs an electrical signal corresponding to the weight of the object to be measured. an electrical output corresponding to the weight of the tare for weighing included in the output of both the load converters, and an electrical output corresponding to the weight of the correction weight and the tare for weight. A weight measuring device characterized in that the gains of the first amplifier or the second amplifier are set to be equal.