JP2012208083A - Measuring apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a measuring apparatus capable of measuring with high accuracy by removing vibration influence sufficiently by detecting components of vibration in a plurality of axes to remove the vibration from a weighing signal.SOLUTION: A measuring apparatus 1 comprises: a vibration sensor 100 which is provided in weighing means 21 and detects vibration applied to the weighing means 21 in at least two axial directions different from each other to output a vibration detection signal, respectively; a correction signal generation unit 102 which includes sensitivity correction units 103X, 103Y and 103Z correcting the amplitude of the vibration detection signal of each axis outputted from the vibration sensor 100 at a predetermined sensitivity ratio, respectively, and which generates a correction signal for removing vibration components included in the weighing signal based on a vibration signal of each axis where the amplitude is corrected; a signal synthesis unit 108 which synthesizes the weighing signal and the correction signal, and thereby removing the vibration components from the weighing signal; and weighing means 72 which calculates a measuring value of an object to be measured W by receiving the weighing signal which is outputted from the signal synthesis unit 108 and from which the vibration components are removed.

Description

  The present invention relates to a weighing device that measures quality by weighing an object to be weighed such as meat, fish, processed food, and medicine.

  2. Description of the Related Art Conventionally, in a production line for foods, etc., articles that are incorporated into the production line are sequentially carried in from the front stage, weighed while transporting the carried-in articles, and are removed from the production line by carrying out or sorting to the subsequent stage. A weighing device is used.

  Since such a weighing device is installed in a production line, floor vibrations caused by other production equipment, low-cycle vibration components due to the rollers and belts of the weighing conveyor, etc., become noise components in the output signal of the weighing instrument. Superimposing constantly is a factor that deteriorates the weighing accuracy.

  As a conventional vibration removal method, a technique for removing a vibration component by attaching a vibration sensor to a free end or a fixed end of a load cell body is known (for example, see Patent Document 1).

  In addition, as a conventional vibration removal method, the output signal of the weighing instrument is divided by the gravitational acceleration detected by the gravitational acceleration sensor to obtain the total mass of the weighing platform and the object to be weighed, and the mass of the weighing platform is calculated from the total mass. There is known a technique in which the mass of an object to be weighed is obtained by subtraction (see, for example, Patent Document 2).

JP 2004-309148 A JP-A-10-339660

  However, the vibration effect is affected by the weight of the weighing platform, the unbalanced load that can occur when the center of gravity of the weighing platform and the center of gravity of the weighing platform are inconsistent in the structure of the weighing device where the weighing platform is supported on the free end of the balance. Since the level changes and the vibration direction becomes a multi-axis component, the conventional measuring device that detects the vibration component in one axis direction as in Patent Documents 1 and 2 can sufficiently eliminate the vibration effect. Therefore, there was a problem that the measurement could not be performed with high accuracy.

  Accordingly, the present invention has been made to solve the conventional problems as described above, and by detecting the components of multiple axes of vibration and removing the vibration from the weighing signal, the vibration effect is sufficiently removed. An object of the present invention is to provide a weighing device capable of measuring with high accuracy.

  The weighing device according to the present invention includes a conveying means for conveying the objects to be weighed sequentially on the weighing table under a predetermined conveying condition, and a weighing signal corresponding to the load of the weighing object placed on the weighing table. Weighing means for outputting, vibration detecting means provided in the weighing means, detecting vibrations applied to the weighing means in at least two different axis directions and outputting respective vibration detection signals, and each of the vibration detection means output Amplitude correction means for respectively correcting the amplitude of the vibration detection signal of the shaft with a predetermined sensitivity ratio, and based on the vibration signal of each axis whose amplitude has been corrected by the amplitude correction means, the vibration component contained in the weighing signal is Correction signal generating means for generating a correction signal for removal; signal weighing means for removing the vibration component from the weighing signal by combining the weighing signal and the correction signal; and the signal combining Output from stage, characterized by comprising a metering means for calculating a metric value of the vibration component weighing signal receiving objects to be weighed which have been removed.

  With this configuration, the vibration detection signal is output by the vibration detection means in at least two different directions, and the correction signal in which the amplitude for removing the vibration component included in the weighing signal is corrected based on the vibration detection signal is the correction signal. The vibration component included in the weighing signal can be satisfactorily removed by generating the correction signal and combining the correction signal with the weighing signal by the signal synthesizing unit. Therefore, by detecting the components of a plurality of axes of vibration and removing the vibration from the weighing signal, the influence of the vibration can be sufficiently removed and the measurement can be performed with high accuracy.

  Moreover, the weighing device according to the present invention is characterized in that the biaxial direction in which the vibration detecting means detects vibration includes at least a vertical direction.

  With this configuration, it is possible to efficiently detect the vibration in the vertical direction that is most easily affected.

  Further, the weighing device according to the present invention is characterized in that both of the two axial directions in which the vibration detecting means detects vibration are inclined at a predetermined angle with respect to the vertical direction.

  This configuration outputs the vibration detection signals at the same level for the vibrations in the vertical direction that are most affected, and combines them to improve the accuracy of the correction signal and more reliably extract the vibration component from the weighing signal. Can be removed.

  The measuring device according to the present invention is characterized in that the two axial directions in which the vibration detecting means detects vibration are orthogonal to each other.

  With this configuration, vibrations in the biaxial directions perpendicular to each other can be detected by the vibration detection means.

  Moreover, the weighing device according to the present invention is characterized in that the vibration detecting means detects vibrations in three axial directions orthogonal to each other.

  With this configuration, in addition to the above effects, a commercially available biaxial or triaxial acceleration sensor can be used, and the configuration can be simplified.

  The present invention can provide a weighing device that can remove the influence of vibration sufficiently and perform measurement with high accuracy by detecting the components of a plurality of axes of vibration and removing the vibration from the weighing signal.

It is a perspective view which shows the outline | summary of the weighing | measuring device which concerns on one embodiment of this invention. It is a block diagram which shows the internal structure of the weighing | measuring device which concerns on one embodiment of this invention. It is a side view which shows the conveyance part of the weighing | measuring device which concerns on one embodiment of this invention. It is a side view which shows the structure of the weighing means of the measuring apparatus which concerns on one embodiment of this invention. (A), (b) is a figure which shows schematic structure of the principal part of the weighing means of the weighing | measuring device which concerns on one embodiment of this invention, and a comprehensive control part. (A) is a figure which shows the weighing signal with which the vibration component output from the weighing means of the weighing | measuring device which concerns on one embodiment of this invention was mixed, (b) is the vibration component output from a vibration sensor. (C) is a figure which shows the weighing signal from which the vibration component output from the signal synthetic | combination part was removed. It is a figure which shows the specific example of the principal part of the weighing means of the weighing | measuring device which concerns on one embodiment of this invention, and a comprehensive control part, and is a figure which shows the case where one 3 axis | shaft acceleration sensor is provided as a vibration sensor. It is a figure which shows the specific example of the principal part of the weighing | measuring means of the weighing | measuring device which concerns on one embodiment of this invention, and a comprehensive control part, and is a figure which shows the case where three uniaxial acceleration sensors are provided as a vibration sensor. (A) is a figure which shows the vibration component of Z-axis, (b) is a figure which shows the vibration component of X-axis, (c) is a figure which shows the vibration component of Y-axis. It is a figure which shows the specific example of the principal part of the weighing means of the weighing | measuring device which concerns on one embodiment of this invention, and a comprehensive control part, and is a figure which shows the case where one biaxial acceleration sensor is provided as a vibration sensor. It is a figure which shows the specific example of the principal part of the weighing means of the weighing | measuring device which concerns on one embodiment of this invention, and a comprehensive control part, and is a figure which shows the case where two uniaxial acceleration sensors are provided as a vibration sensor. It is a figure which shows the specific example of the main part of the weighing | measuring means of the weighing | measuring device which concerns on one embodiment of this invention, and a comprehensive control part, is equipped with one biaxial acceleration sensor as a vibration sensor, and is sensitive to a Z-axis (vertical) direction. It is a figure which shows the case where an axis is not set.

  Hereinafter, embodiments of a weighing device according to the present invention will be described with reference to the drawings.

  1 to 4 show an embodiment of a weighing device according to the present invention.

  As shown in FIGS. 1 and 2, the weighing device 1 includes an apparatus body 2, a transport unit 3, and a carry-in sensor 4. A sorting unit 5 is connected to the subsequent stage of the weighing device 1.

  The weighing device 1 is installed on the downstream side of the belt conveyor 14 constituting a part of the production line, and is to be weighed for meat, fish, processed foods, pharmaceuticals, etc. that are sequentially carried in the direction of arrow A at predetermined intervals. The weight of the object W is measured, and the obtained measurement value is output as a measurement result.

  Further, the weighing device 1 compares the preset upper and lower weight reference values, determines whether or not the obtained measurement value is within the reference value range, and determines that the measured value is within the range. Then, it may be determined whether a product out of the range is defective or not, or the weight rank may be determined corresponding to a plurality of reference values.

  In addition, the measurement result, the pass / fail determination result, and the weight rank determination result are displayed on the display unit 10 and are output to the selection unit 5 connected to the subsequent stage of the weighing device 1.

  The sorting unit 5 distributes the objects to be weighed W according to the measurement result output from the weighing device 1, the pass / fail determination result, and the weight rank determination result.

  The apparatus main body 2 includes a weighing unit 21, a general control unit 7, a display unit 10, a setting unit 11, and a housing 2a that houses these units.

  The conveyance unit 3 is configured to convey the object W to be weighed in from the belt conveyor 14 in the direction of arrow A under predetermined conveyance conditions. The object to be weighed W is conveyed by being accelerated or decelerated so as to have an optimum speed for measurement by the run-up conveyor 31, further conveyed by the weighing conveyor 32, and the weight is measured by the weighing means 21 while being conveyed. It has become so.

  The weighing conveyor 32 is configured to convey an object to be weighed according to predetermined conveyance conditions. In addition, the object to be weighed W is further transported to the sorting unit 5 in the subsequent stage after the weighing and is distributed.

  The transport unit 3 includes a running conveyor 31 and a weighing conveyor 32. The run-up conveyor 31 performs the run-up of the object to be weighed W before the object to be weighed W conveyed from the preceding belt conveyor 14 moves to the weighing conveyor 32, and includes two rollers 31a and 31c, And an endless conveying belt 31b wound around the roller.

  As shown in FIG. 4, the weighing conveyor 32 is supported on an upper portion of the weighing means 21 for weighing the workpiece W, and has two rollers 32 a and 32 c and an endless conveyance wound around these rollers. The belt 32b and the motor 32d that drives the roller 32c are configured. Each of the motor 32d and the roller 32c has a pulley and is driven to rotate by a drive belt.

  In FIG. 4, Gs is the center of the strain body 110 of the weighing means 21, and Gt is the center of gravity of the weighing conveyor 32 that is fixed in a state where a load is applied to the weighing means 21. The center of gravity of the weighing conveyor 32 is located away from the center line C due to the arrangement of the motor 32d. The center line C is a vertical line including the fixed positions of the weighing means 21 and the weighing conveyor 32.

  When the floor surface vibrates in the Z direction, the load of the weighing conveyor 32 fixed to the weighing means 21 acts in the Z direction with the center of gravity Gt as the mass point. At this time, the vibration component of the load of the weighing conveyor 32 generates a moment with respect to the center Gs of the weighing means 21. Similarly, when the floor surface vibrates in the Y direction or X direction, the vibration component of the load of the weighing conveyor 32 generates a moment with respect to the center Gs of the weighing means 21.

  Thus, since the center Gs of the weighing means 21 and the center of gravity Gt of the weighing conveyor 32 do not coincide with each other, in order to accurately correct the load fluctuation due to floor vibration in each direction (X, Y, Z), In addition to the vibration component corresponding to the strength (acceleration) of vibration, it is necessary to consider the moment as described above. As described in Japanese Patent Application Laid-Open No. 2002-013971, there is a technique of reducing a moment due to vibration by arranging a heavy motor below the weighing means 21 to lower the center of gravity Gt of the weighing conveyor 32.

  However, since the motor is disposed below the weighing means 21 in order to lower the center of gravity, the structure for stably supporting the motor becomes complicated, the weight increases, and the driving belt for transmitting the driving force becomes longer and driven. A new problem such as an increase in vibration due to vibration of the belt or uneven rotation occurs, and there is a problem in that high-precision weighing is performed at a place where floor vibration occurs. The weighing device 1 according to the present embodiment is configured to solve this problem.

  The carry-in sensor 4 is configured by a transmission photoelectric sensor including a pair of light projecting units 4 a and light receiving units 4 b, and is disposed between the run-up conveyor 31 and the weighing conveyor 32. Specifically, the light projecting unit 4a is disposed on the apparatus main body 2 side of the transport belt 32b, and the light receiving unit 4b is disposed on the other side of the transport belt 32b so as to face the light projecting unit 4a. When the object to be weighed W passes between the light projecting part 4a and the light receiving part 4b, the light receiving part 4b is shielded by the object to be weighed, so that it is detected that the carry-in of the object to be weighed W is started. It has become. The detected carry-in start signal is output to the general control unit 7 in the apparatus main body 2.

  The weighing means 21 is a load sensor that supports the weighing conveyor 32 and outputs a weighing signal based on the load of the object to be weighed. The weighing means 21 has a configuration of an electric resistance wire type scale (load cell), and the object to be weighed W is weighed. While being conveyed by the conveyor 32, a load applied to the weighing means 21 is measured.

  Specifically, the weighing means (load cell) 21 is attached to the metallic strain body 110 and the stress concentration portion of the strain body 110 as shown in FIGS. 5 (a) and 5 (b). And a bridge circuit 113 composed of the electric resistance wires 113a to 113d, and the stress concentration portion of the strain generating body 110 is deformed by receiving a load applied to the weighing means 21, so that the attached electric resistance wire (strain (Gauge) 113a and 113d are compressed and the electric resistance value is decreased, while electric resistance wires (strain gauges) 113b and 113c are expanded and the electric resistance value is increased and the resistance value of bridge circuit 113 is changed. This change in resistance value is measured as a weighing signal.

  The strain generating body 110 has a fixed end 111 fixed to the fixed base 87, and a free end 112 connected to the lower end of a support portion 21 a that receives the load of the weighing conveyor 32.

  A vibration sensor 100 is provided at the fixed end 111 of the strain body 110. The vibration sensor 100 includes one triaxial acceleration sensor that detects triaxial accelerations of the X axis, the Y axis, and the Z axis, and the X axis direction of the vibration at the fixed end 111 of the strain body 110, the Y axis. The vibration component in each direction of the direction and the Z-axis direction is detected and output.

  Here, the X-axis direction is the conveyance direction of the object to be weighed by the belt conveyor 14, and the Y-axis direction is a direction (width direction of the belt conveyor 14) perpendicular to the conveyance direction of the object to be weighed W on the horizontal plane. Yes, the X-axis direction is the vertical direction. As the vibration sensor 100, an acceleration sensor having a natural frequency higher than the natural frequency of the strain body 110 is used.

  The comprehensive control unit 7 includes a signal processing unit 71, a weighing unit 72, a storage unit 73, a control unit 74, a quality determination unit 76, and a mode switching unit 77.

  The signal processing means 71 receives the weighing signal from the weighing means 21 and performs signal processing on the basis of predetermined signal processing conditions to output a signal processed weighing signal, and converts an analog signal into a digital signal. An A / D converter is provided.

  Specifically, the signal processing means 71 has signal-processed only the low-frequency component of the weighing signal using a filter selected from a plurality of low-pass filters of different types and characteristics with respect to the weighing signal from the weighing means 21. Is passed as a weighing signal.

  The signal processing means 71 may select one low-pass filter or a combination of a plurality of low-pass filters. As this low-pass filter, there are a FIR (Finite Impulse Response) filter and an IIR (Infinite Impulse Response) filter.

  The FIR filter is a finite impulse response filter that outputs an output for a predetermined time (finite time) when the impulse response waveform is input, and the IIR filter is an infinite impulse that outputs an attenuation waveform of the impulse response waveform infinitely. It is a response filter.

  Here, the FIR filter constitutes a low-pass filter that passes a predetermined low-frequency component for the weighing signal converted into a digital signal by the A / D converter, and uses a simple averaging process or a known window function. Weighted averaging processing is performed.

  The IIR filter is an analog filter that directly receives a weighing signal (analog weighing signal) from the weighing means 21 and outputs a processed signal to the A / D converter using hardware whose characteristics can be changed, such as a switched capacitor filter. Or a digital filter that receives a digital weighing signal (not shown) from the A / D converter.

  Specifically, as shown in FIG. 7, the signal processing means 71 includes an amplifier 94 that amplifies the weighing signal from the weighing means 21, an A / D converter 96 that digitally converts the amplified signal, and digital conversion. And a filter 97 for filtering the processed signal.

  The weighing means 72 calculates (measured in grams) the measured value of the object W based on the signal-processed weighing signal output from the signal processing means 71. Further, in the weighing means 72, a predetermined reference time Tk has elapsed after the carry-in sensor 4 detects that the object to be weighed W has been carried into the weighing conveyor 32, and the weighing signal from which the weighing signal has been output from the weighing means 21. A measurement value is calculated for the object W. Individual weights calculated by the weighing means 72 are stored in the storage means 73 as calculation data.

  The weighing unit 72 performs weighing when a preset reference time Tk has elapsed after the carry-in sensor 4 detects that the workpiece W has been carried into the weighing conveyor 32. Here, the reference time Tk is detected by the carry-in sensor 4 that the workpiece W has started to be loaded onto the weighing conveyor 32, and then the workpiece W has completely transferred to the weighing conveyor 32, and further from the weighing means 21. This means the time required for the output weighing signal to stabilize.

Specifically, the reference time Tk is the speed of the weighing conveyor 32 (m / min), the length of the weighing conveyor 32 in the direction of arrow B (mm), and the length of the weighing object W in the direction of arrow B, which is the conveyance direction. (Mm), the size of the workpiece W, the processing capacity of the line, and other conditions. Further, as shown in FIG. 3, the reference time Tk has elapsed, the objects to be weighed W is moved by L ₁ reaches the mass measuring position P _S from the loading start detection position P _O, metering is performed.

  In the weighing means 72, inspection conditions (parameters) such as the measurement range, measurement capability, and inspection accuracy are selected according to the type (particularly size) of the object to be weighed W. Depending on the type of the weighing object W, for example, the measurement range is selected from 6 g to 600 g, and the measurement capability is selected at a maximum of 150 pieces / min.

  In this case, the reference time Tk per object W is set to a minimum of 400 msec, and the reference time Tk may be 400 msec or more. It is set according to capacity, production and other conditions.

  Since the reference time Tk is measured in a shorter time as it is closer to 400 msec, the inspection efficiency is increased, and as the distance is longer, the inspection time is longer, but the weighing accuracy is increased because it is stably conveyed on the weighing conveyor 32. Become.

  Further, according to the type of the object to be weighed W, for example, the measurement range is selected from 1 g to 300 g, and the measurement capability is selected at a maximum of 600 pieces / min. If the measurement capacity is 600 pieces / min at the maximum, the measurement time per piece of the object to be weighed W is set to a minimum of 100 msec, and the size of the object to be weighed W, the processing capacity of the line, production, etc. It is set according to the conditions.

  Since the reference time Tk is measured in a shorter time as it is closer to 100 msec, the inspection efficiency is increased. As the distance is longer, the inspection time is longer, but the weighing accuracy is increased because the weighing conveyor 32 is stably conveyed. In this way, in the weighing means 72, the inspection conditions (parameters) such as the range and capability are selected according to the type of the object to be weighed W.

  The storage means 73 is composed of a storage medium and the like, and the condition parameters including the predetermined transport condition of the object W to be weighed by the weighing conveyor 32 and the predetermined signal processing condition in the signal processing means 71 are the types of the object W to be weighed. It corresponds to memorize.

  The storage unit 73 stores a conveyance speed and LPF (Low Pass Filter) characteristics corresponding to each type number assigned to each type of the object to be weighed W. Further, the storage means 73 stores a non-defective range for determining the quality of the object W to be weighed. The conveyance speed is the speed of the conveyance unit 3 that conveys the workpiece W, the LPF characteristic indicates what characteristic the low-pass filter is, and the non-defective range is the non-defective product range. This is the range of the weight of the weighing object W.

  The stored information is stored in advance by a setting operation from the setting unit 11 or connection with an external device. The storage means 73 stores various data such as measurement values and non-defective product determination results.

  The control means 74 reads out a predetermined transport condition and a predetermined signal processing condition from the storage means 73 in accordance with the type of the object to be weighed W, and controls the weighing conveyor 32 and the signal processing means 71, respectively.

  The control means 74 controls the transport unit 3 and the signal processing means 71 by sequentially switching condition parameters corresponding to a plurality of types stored in the storage means 73. Further, the control means 74 is configured to drive and control the rotational speed (rpm) of a motor (not shown) so as to control the transport speed of the workpiece W by the transport unit 3.

  The pass / fail judgment means 76 is for judging pass / fail of the object to be weighed W. The pass / fail judgment means 76 is constituted by a judgment circuit and the like, and compares the weight value calculated by the weighing means 72 with the pass / fail judgment criteria to determine the pass / fail of the object W It comes to judge.

  Specifically, the quality determination unit 76, when receiving the weight signal of the object W output from the weighing unit 72, reads the upper limit value Ga and the lower limit value Gb of the weight stored in advance in the storage unit 73, The calculated weight of the object to be weighed is compared with the upper limit value Ga and the lower limit value Gb, respectively, and whether the weight of the object to be weighed W is within the allowable range determined by the upper limit value Ga and the lower limit value Gb. It is to judge whether.

  The determination result determined by the quality determination unit 76 is output to the display unit 10 and displayed as a non-defective product or a defective product. The determination result is output to the sorting unit 5 connected to the subsequent stage of the weighing device 1 so that the object to be weighed W is sorted as a non-defective product or a defective product. Further, the determination result is output to the storage means 73, and the determination result for each object W is stored.

  The mode switching unit 77 issues a command to the control unit 74 and switches the operation mode of the weighing device 1 between the operation mode and the setting mode. Here, the operation mode is a normal operation mode in which the weighing apparatus 1 performs weighing, weight calculation, and pass / fail judgment of the object to be weighed. The setting mode refers to various parameters for operation in the operation mode. This is an operation mode for confirming whether or not the operation of the operation mode can be performed normally.

  The mode switching unit 77 switches the operation mode to the setting mode according to an input operation from the setting unit 11 or switches the operation mode to the setting mode at the start of operation of the apparatus.

  The overall control unit 7 includes a correction signal generation unit 102 and a signal synthesis unit 108 as shown in FIGS. 2 and 5A. Further, as shown in FIG. 7, the A / D conversion is performed. Devices 101X, 101Y, and 101Z, and sensitivity correction units 103X, 103Y, and 103Z.

  The correction signal generation unit 102 generates a correction signal for removing the influence of vibration from the weighing signal output from the weighing means 21 using the response signal of the control target model with respect to the vibration signal output from the vibration sensor 100. It is.

Specifically, the correction signal generation unit 102 sets the vibration value in the X axis direction to X1,..., Xn, the vibration value in the X axis direction to Y1,..., Yn, and the vibration value in the X axis direction to Z1. ,..., Zn, and a plurality of vibrations (n sets) obtained simultaneously when the weighing value is W1,..., Wn (n is a natural number) and the weighing means 21 has no object W to be weighed. Simultaneous equations a obtained by using a linear combination of component values (Xk, Yk, Zk; k = 1,..., N) as a left side and a weighed value (Wk; k = 1,..., N) as a right side. [X] + b [Y] + c [Z] = [W] is solved and the constants a, b, and c are calculated to obtain a certain point in time to eliminate the vibration effect of the weighing means 21 that is a weighing sensor. The correction signal C (t) at t is generated by synthesizing the vibration components X (t), Y (t), and Z (t) of the vibration sensor 100 by linear combination. Which is way (C (t) = aX (t) + bY (t) + cZ (t)).

  The signal synthesis unit 108 corrects the correction signal generated by the correction signal generation unit 102 (see FIG. 6B) with respect to the weighing signal (see FIG. 6A) mixed with the vibration component output from the weighing means 21. Are added in the opposite phase or subtracted in the same phase, thereby removing the vibration component from the weighing signal output from the weighing means 21. Thereby, a weighing signal having no vibration influence as shown in FIG. 6C is obtained.

  As shown in FIG. 7, between the vibration sensor 100 and the correction signal generation unit 102, an X-axis vibration component, a Y-axis vibration component, and a Z-axis vibration component from the vibration sensor 100 are analog signals. A / D converters 101X, 101Y, and 101Z for converting digital signals into digital signals are provided.

  Further, between the correction signal generation unit 102 and the signal synthesis unit 108, the amplitude correction is performed with a predetermined sensitivity ratio for each of the X-axis, Y-axis, and Z-axis correction signals generated by the correction signal generation unit 102. Sensitivity correction units 103X, 103Y, and 103Z are provided.

  That is, in this embodiment, the X-axis, Y-axis, and Z-axis vibration components output from the vibration sensor 100 are converted from analog signals to digital signals by the A / D converters 101X, 101Y, and 101Z. Correction signal generation unit 102 generates X-axis, Y-axis, and Z-axis correction signals based on the vibration components, and the generated correction signals are amplitude-corrected by sensitivity correction units 103X, 103Y, and 103Z, Each correction signal whose amplitude has been corrected is combined (added or subtracted) with the weighing signal by the signal combining unit 108.

  The detection of the vibration component by the vibration sensor 100, the generation of the correction signal by the correction signal generation unit 102, and the calculation of the constant (a, b, c) by the signal synthesis unit 108 are performed when the operation mode of the weighing device 1 is the operation mode. Each time an object to be weighed W is carried in, it may be updated by using each vibration component and weighing value of the vibration sensor 100 immediately before carrying in, or when the operation mode is the setting mode, the vibration sensor 100. The constant (a, b, c) is detected by the correction signal generation unit 102 and the constants (a, b, c) are calculated and stored in the storage unit 73. When the operation mode is the operation mode, the signal synthesis unit The signal may be synthesized by 108. The former configuration is suitable when the vibration direction is not constant but changes with time, and the latter configuration is suitable when the vibration direction is constant without change.

  As shown in FIG. 1, the display unit 10 is provided at the upper end of the apparatus main body 2 on the transport unit 3 side, and is configured by a display device such as a liquid crystal display. When the operation mode of the weighing device 1 is the operation mode, the display means 10 displays the operation state of the weighing device 1, the measured value of the object W, and the pass / fail judgment result, and the operation mode of the weighing device 1 is the setting mode. In this case, display related to parameter setting and operation confirmation is performed. The display unit 10 may be configured as a touch panel in which displayed numbers, characters, and the like are input by a touch operation, and may be configured to be integrated with the setting unit 11.

  The sorting unit 5 is connected to the subsequent stage of the weighing device 1 and includes a sorting mechanism unit 5a and a conveyor belt 5b. The sorting mechanism unit 5a is configured by, for example, an extrusion type sorting mechanism.

  The sorting mechanism unit 5a only needs to be able to sort good products and defective products, and may be configured by a sorting mechanism such as a flipper mechanism, a dropout mechanism, or an air jet mechanism. The sorting mechanism unit 5a is configured to transfer the workpiece belt W to the workpiece W determined to be defective while the workpiece W transported from the upstream weighing conveyor 32 is being transported in the arrow B direction by the transport belt 5b. 5b is pushed out in the lateral direction and jet air is sprayed, and the defective object W is discharged from the conveying belt 5b and is distinguished from the non-defective object W by sorting. Yes. The conveyor belt 5b is composed of a roller 5c, a roller (not shown) disposed opposite to the roller 5c, and an endless conveyor belt wound around these rollers. The weighing object W is conveyed downstream at a predetermined speed.

  Further, the conveyance belt 5b is composed of a roller 5c, a roller (not shown) disposed opposite to the roller 5c, and an endless conveyance belt 5d wound around these rollers, and the measurement is finished. The measured object W is conveyed downstream at a predetermined speed.

  Here, in the configuration shown in FIG. 7, the vibration sensor 100 is configured as a three-axis acceleration sensor that detects and outputs each of the X-axis, Y-axis, and Z-axis vibration components. 8, three uniaxial acceleration sensors, that is, a vibration sensor 100X that detects and outputs a vibration component of the X axis, a vibration sensor 100Y that detects and outputs a vibration component of the Y axis, and a Z axis The vibration sensor 100Z that detects and outputs the vibration component of the above may be used.

  Of the three vibration components, the Z-axis vibration component has the largest amplitude as shown in FIG. 9A, and the X-axis vibration component has the Z axis as shown in FIG. 9B. As shown in FIG. 9C, the amplitude of the vibration component of the Y-axis is the smallest, as shown in FIG.

  Therefore, even if the detection of the vibration component of the Y axis with the smallest amplitude is omitted and the correction signal is generated from the two vibration components of the Z axis and the X axis, the vibration component is sufficiently obtained from the weighing signal. Can be removed.

  That is, as shown in FIG. 10, the vibration sensor 100XZ including a biaxial acceleration sensor is provided instead of the vibration sensor 100, and the Y-axis A / D converter 101Y and the sensitivity correction unit 103Y are omitted. be able to.

  In this case, the vibration sensor 100XZ detects the X-axis and Z-axis vibration components, and the X-axis and Z-axis vibration components output from the vibration sensor 100 are converted from analog signals by the A / D converters 101X and 101Z. The signal is converted into a signal, and the correction signal generator 102 generates X-axis and Z-axis correction signals based on these vibration components. The generated correction signals are amplitude-corrected by the sensitivity correction units 103X and 103Z, respectively. The amplitude-corrected correction signals are combined (added or subtracted) with the weighing signal by the signal combining unit 108. As the vibration sensor 100XZ, for example, a capacitance type acceleration sensor using comb-shaped electrodes, a piezoelectric type acceleration sensor having a structure in which a beam portion having a cantilever structure is supported by a piezoelectric element, or the like can be used. . In these acceleration sensors, the ratio of the vibration components other than the main sensitivity direction to be detected (other-axis sensitivity) is about several percent (2 to 5%), and each vibration component is accurately detected to generate a correction signal. can do.

  In addition, as shown in FIG. 11, instead of the vibration sensors 100 and 100XZ, vibration sensors 100X and 100Z including single-axis acceleration sensors are provided, and the Y-axis A / D converter 101Y and the sensitivity correction unit 103Y are omitted. Can be configured.

  In this case, the vibration sensor 100X detects the X-axis vibration component, the vibration sensor 100Z detects the Z-axis vibration component, and the X-axis and Z-axis vibration components output from the vibration sensors 100X and 100Z are The analog signals are converted into digital signals by the A / D converters 101X and 101Z, the correction signal generation unit 102 generates the X-axis and Z-axis correction signals based on these vibration components, and the generated correction signals. Are corrected for amplitude by the sensitivity correction units 103X and 103Z, and each correction signal subjected to amplitude correction is combined (added or subtracted) by the signal combining unit 108 with the weighing signal. As the vibration sensors 100X and 100Z, it is preferable to use a high-sensitivity type semiconductor acceleration sensor with a detectable acceleration range of ± several G (G represents gravitational acceleration). From what is introduced in “Chapter 9” (published by CQ Publishing Company, 2006), various specifications such as the number of detection axes (1 to 3 axes), detection sensitivity (mV / G), and size are examined and selected. Will be.

  In the present embodiment, the weighing means 21 is configured as an electric resistance wire type balance provided with the strain body 110. However, the weighing means 21 may be an electromagnetic balance type balance (force balance) or a differential transformer type. The structure of a scale may be sufficient.

  When the weighing means 21 has a configuration of an electromagnetic balance type balance or a differential transformer type balance, the vibration sensor 100, 100X, 100Y, 100Z or 100XZ can be used to detect a vibration in the weighing means 21 satisfactorily, for example, a support unit. What is necessary is just to provide in the site | part corresponding to 21a.

  Furthermore, the sensitivity axis of the acceleration sensor does not necessarily include the vertical direction (Z), and the sensitivity axes of the acceleration sensors do not have to be orthogonal to each other. This is because the correction signal for removing the vibration component of the weighing means 21 is obtained by synthesis by linear combination of a plurality of acceleration sensors, so that the sensitivity direction of each acceleration sensor only needs to be a primary independent relationship. Is based. That is, when two or three uniaxial acceleration sensors are used, it is not necessary to set the sensitivity axis of each acceleration sensor in the vertical direction. Specifically, when detecting vibrations in the three-axis directions, the sensitivity axes of each acceleration sensor are attached so as to be linearly independent (I, J, K), and signals from these acceleration sensors are respectively X Treated as a component, a Y component, and a Z component, a correction signal is generated by linear combination as C (t) = aX (t) + bY (t) + c (t). As described above, if the sensitivity axes are linearly independent from each other, a highly accurate correction signal can be generated even if the angles of the sensitivity axes are somewhat varied or inclined.

  Also, in the case of using a biaxial acceleration sensor or a triaxial acceleration sensor, one of the sensitivity axes may not be set in the vertical direction as in the case of using the uniaxial acceleration sensor. For example, the biaxial acceleration sensor includes two acceleration detecting elements having orthogonal sensitivity axes. Usually, the vibration acting on the weighing means 21 is mainly in the vertical direction (Z direction), the other direction (X direction or Y direction) is about 1/3 to 1/10, and the vibration level is small. Will be buried in the noise signal. In such a case, the constants (a, b, c) are obtained using the noise signal, and the vibration component may not be accurately removed with the correction signal. In such a case, the vertical direction is rather set. It is better not to include it in the sensitivity axis.

  FIG. 12 shows an example of a configuration in which vibrations in three axial directions (I, J, K) that are not mutually included in the vertical direction are detected, correction signals are calculated, and vibration components are removed from the weighing signal. Further, vibration in the biaxial direction by the two axes of J and K axes excluding the I axis may be detected. In any case, even if the mounting direction varies slightly using three or two uniaxial acceleration sensors, the accuracy of the correction signal does not deteriorate because a constant for combining the vibration signals is appropriately calculated. In addition, it can implement more easily if a 2-axis or 3-axis acceleration sensor is used.

  As described above, the weighing device 1 according to the present embodiment is placed on the weighing conveyor 32 and the weighing conveyor 32 that convey the objects W to be sequentially loaded on the weighing conveyor 32 under predetermined conveying conditions. The weighing means 21 for outputting a weighing signal according to the load of the weighing object W and the weighing means 21 are provided in the weighing means 21 to detect vibrations applied to the weighing means 21 in at least two different axial directions and output respective vibration detection signals. And the sensitivity correction units 103X, 103Y, and 103Z that correct the amplitude of the vibration detection signal of each axis output from the vibration sensor 100 with a predetermined sensitivity ratio, respectively, and these sensitivity correction units 103X, 103Y, and 103Z Based on the vibration signal of each axis whose amplitude is corrected, a correction signal generation unit 1 that generates a correction signal for removing a vibration component included in the weighing signal. 2, the weighing signal and the correction signal are combined to remove the vibration component from the weighing signal, and the signal combining unit 108 receives the weighing signal output from the signal combining unit 108 and from which the vibration component is removed. And weighing means 72 for calculating a measured value of W.

  With this configuration, the vibration sensor 100 outputs vibration detection signals in at least two different axis directions, and a correction signal whose amplitude for correcting the vibration component included in the weighing signal is corrected based on the vibration detection signal is a correction signal. The vibration component included in the weighing signal can be satisfactorily removed by generating the correction signal and combining the correction signal with the weighing signal by the signal combining unit 108.

  Therefore, by detecting the components of a plurality of axes of vibration and removing the vibration from the weighing signal, the influence of the vibration can be sufficiently removed and the measurement can be performed with high accuracy.

  In addition, the weighing device 1 according to the present embodiment is characterized in that the biaxial direction in which the vibration sensor 100 detects vibration includes at least the vertical direction.

  With this configuration, it is possible to efficiently detect the vibration in the vertical direction that is most easily affected.

  If the detection of the vibration component in the Y-axis direction, which has a small influence on the weighing signal, is omitted, the vibration sensor 100 can be downsized while maintaining good removal of the multi-axis vibration component included in the weighing signal. The correction signal generation unit 102, the sensitivity correction units 103X, 103Y, and 103Z, and the signal synthesis unit 108 can be downsized.

  In addition, the weighing device 1 according to the present embodiment is characterized in that the biaxial direction in which the vibration sensor 100 detects vibration is inclined at a predetermined angle with respect to the vertical direction.

  This configuration outputs the vibration detection signals at the same level for the vibrations in the vertical direction that are most affected, and combines them to improve the accuracy of the correction signal and more reliably extract the vibration component from the weighing signal. Can be removed.

  Further, the weighing device 1 according to the present embodiment is characterized in that the biaxial directions in which the vibration sensor 100 detects vibration are orthogonal to each other.

  With this configuration, the vibration sensor 100 can detect vibrations in two axial directions orthogonal to each other.

  Further, the weighing device 1 according to the present embodiment is characterized in that the vibration sensor 100 detects vibrations in three axial directions orthogonal to each other.

  With this configuration, in addition to the above effects, a commercially available biaxial or triaxial acceleration sensor can be used, and the configuration can be simplified.

  As described above, the weighing device according to the present invention can perform measurement with high accuracy by sufficiently removing the influence of vibration by detecting vibration components from a plurality of axes and removing vibration from the weighing signal. It is useful as a weighing device that measures the quality of objects to be weighed such as meat, fish, processed foods, and pharmaceuticals.

DESCRIPTION OF SYMBOLS 1 Weighing device 3 Conveyance part 7 General control part 14 Belt conveyor (conveyance means)
21 Weighing means 21a Support section 32 Weighing conveyor (weighing table)
71 Signal processing means 72 Measuring means 73 Storage means 74 Control means 76 Pass / fail judgment means 77 Mode switching means 87 Fixed base 94 Amplifier 96 A / D converter 97 Filter 100, 100X, 100Y, 100Z, 100XZ Vibration sensor (vibration detection means)
101X, 101Y, 101Z A / D converter 102 Correction signal generation unit (correction signal generation means)
103X, 103Y, 103Z Sensitivity correction unit (amplitude correction means)
108 Signal Synthesizer (Signal Synthesizer)
110 Strain body 111 Fixed end 112 Free end W Object to be weighed

Claims (5)

Conveying means (14) for conveying the objects to be weighed (W) sequentially put on the weighing table (32) under predetermined conveying conditions;
Weighing means (21) for outputting a weighing signal according to the load of the object to be weighed placed on the weighing table;
Vibration detecting means (100) provided in the weighing means, for detecting vibrations applied to the weighing means in at least two different axial directions and outputting a vibration detection signal;
Amplitude correction means (103X, 103Y, 103Z) for correcting the amplitude of the vibration detection signal of each axis output by the vibration detection means with a predetermined sensitivity ratio, respectively, and for each axis whose amplitude has been corrected by the amplitude correction means Correction signal generating means (102) for generating a correction signal for removing a vibration component included in the weighing signal based on a vibration signal;
A signal synthesis means (108) for removing the vibration component from the weighing signal by synthesizing the weighing signal and the correction signal;
A weighing apparatus, comprising: weighing means (72) that receives a weighing signal output from the signal synthesizing means and that receives the weighing signal from which the vibration component has been removed, and calculates a weighing value of the object to be weighed.   The weighing apparatus according to claim 1, wherein the biaxial direction in which the vibration detecting unit detects vibration includes at least a vertical direction.   2. The weighing apparatus according to claim 1, wherein both of the two axial directions in which the vibration detecting unit detects vibration are inclined at a predetermined angle with respect to the vertical direction.   The weighing device according to any one of claims 1 to 3, wherein the two axial directions in which the vibration detecting means detects vibration are orthogonal to each other.   The weighing apparatus according to claim 1, wherein the vibration detection unit detects vibrations in three axial directions orthogonal to each other.

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