JP5977960B2 - Mass measuring device - Google Patents

Description

  The present invention relates to a mass measuring apparatus, and more particularly, to an apparatus that moves an article and calculates the mass of the article from the force and acceleration acting on the article.

  In general, spring balances and electronic balances are assumed to be used in a stationary state in order to eliminate the influence of acceleration other than gravitational acceleration. However, in recent years, mass measuring apparatuses that are installed on a swinging object and measure a mass from which a weighing error due to the swinging is removed have become widespread. For example, in the mass measuring device disclosed in Patent Document 1 (Japanese Patent Application Laid-Open No. 8-110261), the vertical movement component of the floor is a dummy load cell loaded with a weight separately from the weighing load cell as a normal force sensor. Is detected, and the detected vertical movement component is subtracted from the output signal of the weighing load cell to output a measurement signal that does not include the vertical movement component of the floor.

  Since the mass measuring device described in Patent Document 1 also utilizes the fact that the load cell is displaced in the vertical direction due to gravity acting on the article, if the load cell is not displaced by gravity, the mass of the article is changed. It cannot be detected.

  Therefore, for example, when a load cell is attached to a tip part that lifts and moves an article, such as a manipulator or a robot hand, and the mass of the article is measured while the lifted article is moving, It is difficult with technology.

  Therefore, the applicant has developed a mass measuring device that moves the article and calculates the mass of the article from the force and acceleration acting on the article. That is, in this apparatus, the force acting on the horizontally moving article is measured by the force sensor, and the acceleration acting on the horizontally moving article is measured by the acceleration sensor. Based on the measurement data of each sensor, The mass of the article is calculated.

  However, force sensors and acceleration sensors individually have frequency characteristics. This frequency characteristic may cause a phase shift in the measurement data of each sensor, and may adversely affect the calculation of the mass of the article. As a result, the calculated mass of the article may be different from the actual mass of the article.

  Therefore, an object of the present invention is to provide a mass measuring apparatus that can accurately measure the mass of a moving article without being significantly affected by the frequency characteristics of the sensor.

The mass measuring apparatus moves the article and calculates the mass of the article from the force and acceleration acting on the article. The mass measuring device includes a holding mechanism, a moving mechanism, a force measuring unit, an acceleration grasping unit, and a control unit. The holding mechanism holds the article. The moving mechanism moves the holding mechanism. The force measuring unit is provided between the holding mechanism and the moving mechanism, and measures the force acting on the article during movement. The acceleration grasping unit grasps acceleration acting on the article during movement. The control unit controls the operation of the holding mechanism and the moving mechanism, and calculates the mass of the article based on the force measurement data indicating the measurement result of the force measurement unit and the acceleration data grasped by the acceleration grasping unit. Then, the control unit, the force measured data extremum or extrema of the acceleration data or to calculate the mass of the article extreme extreme and acceleration data of the force-measuring data from.

  In this mass measuring device, when calculating the mass of an article, at least one of the extreme value of acceleration data and the extreme value of force measurement data is used. If both the force measurement unit and the acceleration grasping unit are configured by sensors, when the measurement data of each sensor takes an extreme value, the amount of displacement of the measurement data with time is the smallest. Therefore, by using the extreme value of each measurement data for the mass calculation of the article, the mass of the article that is not significantly affected by the phase shift due to the frequency characteristics of each sensor is calculated, and as a result, the weighing accuracy is increased. .

  Further, the time when the force measurement data takes the extreme value is different from the time when the acceleration data takes the extreme value, and both the extreme value of the force measurement data and the extreme value of the acceleration data are used in calculating the mass of the article. It is preferable.

  Here, each data has an extreme value at different times, but both the extreme value in the force measurement data and the extreme value in the acceleration data are used for calculating the mass of the article. This makes it possible to calculate the mass of the article with higher accuracy.

  In addition, the time when the force measurement data takes the extreme value is different from the time when the acceleration data takes the extreme value, and when the extreme value of the force measurement data is used in the calculation of the mass of the article, the data takes the extreme value. The value of the acceleration data at the sampling time is further used in calculating the mass of the article. When the extreme value of the acceleration data is used in the calculation of the mass of the article, it is preferable that the value of the force measurement data at the time when the data takes the extreme value is further used in the calculation of the mass of the article.

  Here, an extreme value is used as one of acceleration data and force measurement data, and the other data at that time is used. Thereby, since each data at the moment when one condition is imposed on the article is used, it is possible to quickly calculate the mass of the article without waiting for each data to be extreme values.

  Moreover, a control part extracts the 1st data applicable in the 1st predetermined range containing the extreme value of this data among force measurement data. The control unit extracts second data corresponding to the second predetermined range including the extreme value of the data from the acceleration data. And it is preferable that a control part calculates the weighted average which makes the extracted 1st data and 2nd data object, and uses the result for calculation of the mass of articles | goods.

  This makes it possible to calculate the mass of the article with higher accuracy.

  According to the mass measuring device of the present invention, the mass of an article that is not significantly affected by the phase shift due to the frequency characteristics of the force measuring unit and the acceleration grasping unit is calculated, and as a result, the weighing accuracy is increased.

It is a schematic block diagram of the mass measuring device which concerns on one Embodiment of this invention, Comprising: The figure showing the drive system of a mass measuring device especially. FIG. 2 is a signal processing circuit diagram for processing signals (that is, force measurement data and acceleration data) detected by a force sensor and an acceleration sensor, and particularly a diagram showing a control system of the mass measuring apparatus. 2 is a two-degree-of-freedom model of the mass measuring device when the mass measuring device of FIG. 1 is represented by a spring-mass system. The graph which shows each measurement data obtained from the force sensor and the acceleration sensor in the state which does not hold | maintain anything at a adsorption | suction part for zero point adjustment. The graph which shows each measurement data obtained from the force sensor and the acceleration sensor in the state which made the adsorption | suction part hold | maintain the known weight for span adjustment. The graph which shows each measurement data obtained from the force sensor and the acceleration sensor in the state which hold | maintained the to-be-measured object (namely, article | item Q) of mass m in the adsorption | suction part. The graph which shows each measurement data in which the shift | offset | difference of phase has arisen used when demonstrating the calculation method of the mass m of the goods Q concretely. The graph which shows the measurement data of each of a force sensor and an acceleration sensor used when demonstrating the calculation method of the mass m of the articles | goods Q concerning the modification A concretely. The graph which shows the measurement data of each of a force sensor and an acceleration sensor used when demonstrating the calculation method of the mass m of the articles | goods Q concerning the modification B concretely.

  Embodiments of the present invention will be described below with reference to the drawings. The following embodiments are specific examples of the present invention and do not limit the technical scope of the present invention.

(1) Configuration of Mass Measuring Device 100 (1-1) Drive System FIG. 1 is a schematic configuration diagram of a mass measuring device 100 according to an embodiment of the present invention, and particularly represents a drive system of the mass measuring device 100. ing. In FIG. 1, a mass measuring apparatus 100 includes, as components of a drive system, a force sensor 1 (corresponding to a force measuring unit), a suction unit 2 (corresponding to a holding mechanism), and a robot arm 3 (corresponding to a moving mechanism). , And an acceleration sensor 4 (corresponding to an acceleration grasping unit).

  The force sensor 1 detects a force acting on the moving article Q. Further, for example, a strain gauge type load cell is employed for the force sensor 1. The strain gauge load cell can detect a force acting on the free end side by moving the free end side relative to the fixed end side by movement.

  The adsorption unit 2 holds the article Q. Further, an air suction mechanism or an air chuck mechanism is employed for the suction portion 2. The suction unit 2 is not limited to an air suction mechanism or an air chuck mechanism, but may be a motor-driven finger mechanism.

  The robot arm 3 moves the suction unit 2 three-dimensionally. The robot arm 3 can also rotate in the CW direction and the CCW direction about a predetermined rotation axis CA. As the robot arm 3, for example, a horizontal articulated robot, a vertical articulated robot, or a parallel link robot is suitable.

  The acceleration sensor 4 detects acceleration acting on the article Q. As the acceleration sensor 4, for example, any one of a strain gauge type load cell, a MEMS type small acceleration sensor, and a general commercially available acceleration sensor is appropriately employed.

  The force sensor 1 is provided between the adsorption unit 2 and the robot arm 3, and the acceleration sensor 4 is provided adjacent to the adsorption unit 2. In the embodiment described below, strain gauge type load cells are employed for both the force sensor 1 and the acceleration sensor 4, and the force sensor 1 and the acceleration sensor 4 detect the force and acceleration acting on the article Q moving in the horizontal direction.

(1-2) Control System FIG. 2 is a signal processing circuit diagram for processing signals detected by the force sensor 1 and the acceleration sensor 4, and particularly shows a control system of the mass measuring apparatus 100. In FIG. 2, the mass measuring apparatus 100 further includes amplifiers 31a and 31b, low-pass filters 32a and 32b, A / D converters 33a and 33b, and a control unit 40 as components of the control system.

  Hereinafter, for convenience of explanation, the detection signal that is the output of the force sensor 1 is referred to as “force measurement data”, and the detection signal that is the output of the acceleration sensor 4 is referred to as “acceleration data”.

  In FIG. 2, amplifiers 31 a and 31 b are connected to the force sensor 1 and the acceleration sensor 4, respectively. These amplifiers 31 a and 31 b measure force that is a detection signal input from the force sensor 1 and the acceleration sensor 4. Data and acceleration data are amplified. Further, low-pass filters 32a and 32b are connected to the amplifiers 31a and 31b, respectively. The low-pass filters 32a and 32b remove noise components of a certain frequency or more from force measurement data and acceleration data that are input detection signals. Further, A / D converters 33a and 33b are connected to the low-pass filters 32a and 32b, respectively. The A / D converters 33a and 33b are connected to the input analog signal (specifically, each measurement Data) into a digital signal. The A / D converters 33 a and 33 b are connected to the control unit 40. As the control unit 40, a DSP (digital signal processor), a microcomputer, or the like can be used.

  The control unit 40 executes various processes based on the input detection signal, that is, force measurement data and acceleration data. First, the control unit 40 performs a process of removing noise frequency components included in the measurement data of the force sensor 1 and the acceleration sensor 4 by the low-pass filters 32a and 32b. And the control part 40 performs the process which divides the force measurement data of the force sensor 1 from which the noise frequency component was removed by the acceleration data of the acceleration sensor 4 by functioning as the divider 41. Thereafter, the control unit 40 functions as the subtractor 42 to perform a process of calculating the mass m by subtracting the tare mass from the division result. That is, the control unit 40 calculates the mass m of the article Q based on the measurement data of the force sensor 1 and the acceleration sensor 4. The tare mass is the sum of the tare mass loaded on the force sensor 1, the mass of the adsorption unit 2, and the mass of the acceleration sensor 4.

  Further, the control unit 40 also controls the suction operation of the article Q by the suction unit 2 and the operation control of the robot arm 3.

(2) Principle of Mass Measurement FIG. 3 is a two-degree-of-freedom model of the mass measuring device when the mass measuring device 100 of FIG. 1 is represented by a spring-mass system.

In FIG. 3, m is the mass of the article Q, M ₁ is the sum of the mass at the free end side of the force sensor 1, the mass of the suction portion 2 and the mass at the fixed end side of the acceleration sensor 4, and M ₂ is the mass of the acceleration sensor 4. The mass of the free end. K ₁ is the spring constant of the force sensor 1, and k ₂ is the spring constant of the acceleration sensor 4. x ₁ is the displacement amount of the force sensor 1, and x ₂ is the displacement amount of the acceleration sensor 4.

The equation of motion when acceleration acts on the article Q is
(M + M ₁ ) d ² x ₁ / dt ² = −k ₁ (x ₁ −y) + k ₂ (x ₁ −x ₂ ) (1)
M ₂ d ² x ₂ / dt ² = −k ₂ (x ₂ −x ₁ ) (2)
Represented as: Moreover, when the equation (1) is transformed,
m = [− k ₁ (x ₁ −y) + k ₂ (x ₁ −x ₂ )] / (d ² x ₁ / dt ² ) −M ₁ (3)
It becomes. Furthermore, considering that the rigidity of the acceleration sensor 4 is large,
d ² x ₁ / dt ² ≈d ² x ₂ / dt ² (4)
Can be approximated as Therefore, from equations (3) and (4)
m = [− k ₁ (x ₁ −y) + k ₂ (x ₁ −x ₂ )] / (d ² x ₂ / dt ² ) −M ₁ (5)
Is derived. Moreover, when the equation (2) is transformed,
d ² x ₂ / dt ² = −k ₂ (x ₂ −x ₁ ) / M ₂ (6)
Therefore, from equations (5) and (6),
m = [− k ₁ (x ₁ −y) / − k ₂ (x ₂ −x ₁ )] M ₂ + M ₂ −M ₁ (7)
Is derived.

Here, −k ₁ (x ₁ −y) is an output of the force sensor 1, and −k ₂ (x ₂ −x ₁ ) is an output of the acceleration sensor 4.

FIG. 4 is a graph showing measurement data obtained from the force sensor 1 and the acceleration sensor 4 in a state where nothing is held by the suction unit 2 for zero point adjustment. In FIG. 4, when the peak value of the force measurement data of the force sensor 1 is Fmz and the peak value of the acceleration data of the acceleration sensor 4 is Faz, from the equation (7),
0 = M ₂ · C · (Fmz / Faz) + M ₂ −M ₁ (8)
It becomes. However, it is assumed that the acceleration is not zero. C is a conversion coefficient.

FIG. 5 is a graph showing measurement data obtained from the force sensor 1 and the acceleration sensor 4 in a state where a known weight for span adjustment is held in the suction portion 2. In FIG. 5, when the peak value of the force measurement data of the force sensor 1 is Fms and the peak value of the acceleration data of the acceleration sensor 4 is Fas,
ms = M ₂ · C · (Fms / Fas) M ₂ −M ₁ (9)
It becomes. And from the equations (8)-(9),
C = ms / M ₂ {(Fms / Fas) − (Fmz / Faz)} (10)
Is derived. From equation (10), if M ₂ is a fixed coefficient and the span coefficient is S,
S = C · M ₂ = ms / {(Fms / Fas) − (Fmz / Faz)} (11)
It is.

FIG. 6 is a graph showing measurement data obtained from the force sensor 1 and the acceleration sensor 4 in a state in which an object to be measured (that is, the article Q) having a mass m is held by the suction unit 2. In FIG. 6, when the peak value of the force measurement data of the force sensor 1 is Fm and the peak value of the acceleration data of the acceleration sensor 4 is Fa,
m = S {(Fm / Fa)-(Fmz / Faz)} (12)
It becomes.

(3) Means for Finding Mass m Regardless of Frequency Characteristics of Sensors 1 and 4 FIG. 7 shows measurement data of the force sensor 1 and the acceleration sensor 4 when a phase shift occurs. The vertical axis in FIG. 7 represents the force acting on the article Q indicated by the value of the force measurement data or the acceleration of the article Q indicated by the value of the acceleration data, and the horizontal axis represents time.

  Depending on the frequency characteristics of the sensors 1 and 4, as shown in FIG. 7, a phase difference occurs between the force measurement data and the acceleration data. As a result, the time when the force measurement data takes an extreme value and the acceleration data Are different from each other at the time when takes an extreme value.

  Therefore, in the calculation of the mass m of the article Q described in the above principle of mass measurement, the control unit 40 of the mass measuring device 100 according to the present embodiment uses the extreme value of the force measurement data of the force sensor 1 and the acceleration sensor 4. At least one of the extreme values of the acceleration data is used. In particular, in the present embodiment, both the extreme value of the force measurement data and the extreme value of the acceleration data are used for calculating the mass m of the article Q.

  Specifically, in FIG. 7, the force measurement data of the force sensor 1 is decelerated on the contrary to the extreme value a1 at which the force acting on the article Q is maximum when the article Q is accelerated in the horizontal direction. The two extreme values are the extreme value a2 at which the force acting on the article Q is maximized. The acceleration data of the acceleration sensor 4 indicates that the extreme value b1 that maximizes the acceleration of the article Q when the article Q is accelerated in the horizontal direction and the degree of deceleration of the article Q when the article Q is decelerated are maximum. It has two extreme values, i.e., an extreme value b2. In this case, as a combination of the force measurement data and the acceleration data used by the mass measuring apparatus 100 in calculating the mass m of the article Q, the extreme value a1 of the force measurement data, the extreme value b1 of the acceleration data, and the extreme value a2 of the force measurement data. And the extreme value b2 of acceleration data.

  In calculating the mass m of the article Q, the control unit 40 stores all of the force measurement data of the force sensor 1 and the acceleration data of the acceleration sensor 4 when the article Q is moved in the horizontal direction. Remember). And the control part 40 extracts the combination of the force measurement data and acceleration data which become an extreme value mutually from all this memorize | stored data, and uses this in the principle of said mass measurement, The article Q's The mass m is calculated.

  Thus, when the measurement data of the sensors 1 and 4 take extreme values, even if the sensors 1 and 4 have frequency characteristics, the amount of displacement over time of the measurement data is the lowest. Therefore, by using the extreme values of the measurement data of the sensors 1 and 4 for calculation of the mass m of the article Q, the control unit 40 can affect this even if there is a phase shift in the measurement data due to the frequency characteristics. It is possible to obtain the mass m of the article Q with high accuracy that has not been relatively received.

  In addition, in the extreme value of each measurement data mentioned above, the measurement data near an extreme value, ie, the measurement data of about an extreme value shall be included.

(4) Features (4-1)
The mass measuring apparatus 100 according to the present embodiment uses at least one of the extreme value of acceleration data and the extreme value of force measurement data when calculating the mass m of the article Q. When the measurement data of the force sensor 1 or the acceleration sensor 4 takes an extreme value, the amount of displacement with time of the data becomes the smallest. Therefore, by using the extreme values of the measurement data of the force sensor 1 and the acceleration sensor 4 for the calculation of the mass m of the article Q, the article Q that is not significantly affected by the phase shift due to the frequency characteristics of the sensors 1 and 4 is used. The mass m is calculated, and as a result, the weighing accuracy is increased.

(4-2)
In particular, as shown in FIG. 7, the force measurement data and the acceleration data become extreme values at different times, but the control unit 40 according to the present embodiment uses the force measurement data in the calculation of the mass m of the article Q. Both extreme values and extreme values in acceleration data are used. Thereby, the mass m of the article Q can be calculated with higher accuracy.

(5) Modification (5-1) Modification A
In the above embodiment, the case where both the extreme value of the force measurement data of the force sensor 1 and the extreme value of the acceleration data of the acceleration sensor 4 are used in calculating the mass m of the article Q has been described. However, either one of the force measurement data and the acceleration data used for calculating the mass m of the article Q may be an extreme value.

  That is, when the extreme value of the force measurement data is used, the extreme value of the force measurement data and the value of the acceleration data at the time when the data takes the extreme value are used for calculating the mass m of the article Q. Conversely, when the extreme value of the acceleration data is used, the extreme value of the acceleration data and the extreme value of the force measurement data at the time when the data takes the extreme value are used for calculating the mass m of the article Q. . Specifically, in FIG. 8, force measurement data of the force sensor 1 takes extreme values a3 and a5 at time t3 and time t5, and acceleration data of the acceleration sensor 4 takes extreme values at time t4 and time t6. Take b4 and b6. Therefore, the control unit 40 assumes that the force measurement data takes an extreme value, a combination of the force measurement data extreme value a3 and the acceleration data value b3 at time t3, or the force measurement data extreme value a5 at time t5 and A combination of the acceleration data values b5 is used to calculate the mass m of the article Q. Alternatively, when the acceleration data takes an extreme value, the control unit 40 combines the force measurement data value a4 and the acceleration data extreme value b4 at time t4, or the force measurement data value a6 and acceleration data at time t6. Are used for calculating the mass m of the article Q.

  In FIG. 8, as in FIG. 7, the vertical axis of FIG. 8 represents the force acting on the article Q indicated by the value of the force measurement data or the acceleration of the article Q indicated by the value of the acceleration data, and the horizontal axis is Represents time.

  Thereby, although the calculation accuracy of the mass m of the article Q is inferior to the case of the above embodiment, each measurement data at the moment when one condition is imposed on the article Q is used. The mass m of the article Q can be calculated without waiting for the case where each measurement data is an extreme value. Therefore, since the extreme value in the measurement data of one of the sensors 1 and 4 is used to calculate the mass m of the article Q, the measurement of the article Q can be performed as compared with the above embodiment while maintaining a certain level of measurement accuracy. The mass m can be calculated quickly.

(5-2) Modification B
In the embodiment and the modification A, the control unit 40 further performs weighted averaging on a plurality of force measurement data and acceleration data within a certain threshold value including extreme values, and uses the result as the principle of mass measurement. It may be used in the calculation of the mass m of the article Q described above.

  Specifically, as shown in FIG. 9, the control unit 40, among the force measurement data of the force sensor 1, data corresponding to a first predetermined range including the extreme value a1 or the extreme value a2 of the data (hereinafter, the data) , Referred to as first data). Further, as shown in FIG. 9, the control unit 40 includes data corresponding to a second predetermined range including the extreme value b1 or the extreme value b2 of the acceleration sensor 4 (hereinafter, second data). Extract). And it is preferable that the control part 40 calculates the weighted average which makes the extracted 1st data and 2nd data object, and uses the result for calculation of the mass m of the article | item Q. FIG. Thereby, the mass m of the article Q can be calculated with higher accuracy.

  9, as in FIGS. 7 to 8, the vertical axis in FIG. 9 represents the force acting on the article Q indicated by the force measurement data value or the acceleration of the article Q indicated by the acceleration data value, and the horizontal axis. Represents time.

  Here, it is preferable that the first predetermined range is set so as to always include an extreme value of force measurement data, and the second predetermined range is set so as to necessarily include an extreme value of acceleration data. These first predetermined range and second predetermined range are determined by a method such as desktop calculation, simulation, and experiment according to the specifications of the mass measuring apparatus 100 (specifically, the robot arm 3 and the sensors 1 and 4). It is determined appropriately.

  Alternatively, the first predetermined range and the second predetermined range are centered on the extreme values of each of the measurement data after all the measurement data is taken into the storage unit (not shown) while actually moving the article Q in the horizontal direction. It may be determined to have a predetermined width. In this case, the control unit 40 extracts each measurement data included in each of the determined first predetermined range and second predetermined range, performs weighted averaging, and uses the result for calculating the mass m of the article Q. .

  Further, the weighted average may be performed only on one of the extreme values a2 and b2 on the upper side and the lower extreme values a1 and b1 on the measurement data according to FIG.

  Alternatively, the control unit 40 increases the weighting for the first data and the second data including the upper extreme values a2 and b2 according to FIG. 9, and conversely the lower extreme values a1 and b1 according to FIG. For the first data and the second data including, the weighted average may be performed by reducing the weight.

(5-3) Modification C
In the above embodiment, it has been described that the mass measuring device 100 includes the “acceleration sensor 4” as a device for grasping the acceleration of the moving article Q. However, the acceleration of the moving article Q is not actually detected by the acceleration sensor 4 but may be grasped from, for example, a drive command output to the robot arm 3. In this case, the mass measuring device 100 does not need to include the acceleration sensor 4, but when calculating the mass m of the article Q, the extremum of the force measurement data of the force sensor 1 and the acceleration grasped from the drive command are used. It becomes.

  As described above, according to the present invention, since the mass of an article can be measured while the article is moved, the present invention is also useful for a shortage inspection of internal parts of an assembly product.

1 Force sensor (force measuring unit)
2 Adsorption part (holding mechanism)
3 Robot arm (movement mechanism)
4 Acceleration sensor (acceleration grasping part)
40 Control part Q Goods (objects to be weighed)

JP-A-8-110261

Claims (4)

A mass measuring device that moves the article and calculates the mass of the article from the force and acceleration acting on the article at that time,
A holding mechanism for holding the article;
A moving mechanism for moving the holding mechanism;
A force measuring unit that is provided between the holding mechanism and the moving mechanism and measures a force acting on the article during movement;
An acceleration grasping unit for grasping acceleration acting on the article at the time of movement;
A control unit that controls the operation of the holding mechanism and the moving mechanism, and calculates mass of the article based on force measurement data indicating a measurement result of the force measurement unit and acceleration data grasped by the acceleration grasping unit;
With
Wherein the control unit, the power measurement data extremum or the acceleration data extremum or calculates the mass of said article from said power measurement data of extreme values and the acceleration data extremes,
Mass measuring device. The time when the force measurement data takes an extreme value is shifted from the time when the acceleration data takes an extreme value,
In the calculation of the mass of the article, both the extreme value of the force measurement data and the extreme value of the acceleration data are used.
The mass measuring device according to claim 1. The time when the force measurement data takes an extreme value is shifted from the time when the acceleration data takes an extreme value,
When the extreme value of the force measurement data is used in calculating the mass of the article, the value of the acceleration data at the time when the force measurement data takes the extreme value is further used in calculating the mass of the article. ,
When the extreme value of the acceleration data is used in calculating the mass of the article, the value of the force measurement data at the time when the acceleration data takes the extreme value is further used in calculating the mass of the article.
The mass measuring device according to claim 1. The controller is
Of the force measurement data, extract the first data corresponding to the first predetermined range including the extreme value of the data,
From the acceleration data, second data corresponding to a second predetermined range including the extreme value of the data is extracted,
Calculating a weighted average of the extracted first data and second data, and using the result for calculating the mass of the article;
The mass measuring device according to any one of claims 1 to 3.

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