JP6513367B2 - Mass measuring device - Google Patents

Description

  The present invention relates to a mass measuring device for detecting the mass of an article while the speed of the article is changing.

  In a spring balance and an electronic balance, in order to eliminate the influence of acceleration other than gravity acceleration, it is premised that the mass is measured in a state in which the article is at rest. However, recently, there is an increasing opportunity to lift and move an article with a robot hand, and accordingly, when the article is lifted, there is a demand to detect its mass and use it for post-processing.

  In order to meet this need, the applicant has developed a series of mass measuring devices as disclosed in the following patent documents. This mass measuring device is intended to measure the mass of an article from the force and acceleration acting on the article while the speed of the article changes.

  The basic configuration of the mass measuring device 10 is, as shown in FIG. 1, a force sensor 1 for detecting a force acting on an article Q, a robot hand 2 for lifting the article Q, and a robot arm for moving the article Q while accelerating it. 3 and an acceleration sensor 4 for detecting an acceleration acting on the article Q.

  The force sensor 1 is provided between the robot hand 2 and the robot arm 3, and the acceleration sensor 4 is provided adjacent to the robot hand 2. The mass measuring device 10 having such a configuration can be represented by a two-degree-of-freedom model as shown in FIG.

Based on this model, the principle of measuring the mass of the article during acceleration is described below.
In FIG. 2, m is the mass of the article Q, M 1 is the mass of the force sensor 1, and M 2 is the mass of the acceleration sensor 4. Further, k 1 is a spring constant of the force sensor 1 and k 2 is a spring constant of the acceleration sensor 4. x 1 is the displacement of the force sensor 1, and x 2 is the displacement of the acceleration sensor 4.
These displacements should be calculated by dividing them into three axes of X, Y and Z. However, since the result is the same regardless of which axis they are calculated, here, they are expressed by the synthesized displacements. ing.

In this model, the equation of motion when acceleration acts on the article Q is
(M + M1) d2x1 / dt2 = -k1 (x1-y) + k2 (x1-x2) (1)
M2d2x2 / dt2 = -k2 (x2-x1) (2)
It is represented as Also, if equation (1) is modified,
m = [-k1 (x1-y) + k2 (x1-x2)] / (d2x1 / dt2) -M1 (3)
It becomes. Furthermore, considering that the rigidity of the acceleration sensor 4 is large,
d2x1 / dt2 d d2x2 / dt2 (4)
It can be approximated as Therefore, from equations (3) and (4),
m = [-k1 (x1-y) + k2 (x1-x2)] / (d2x2 / dt2) -M1 (5)
Is derived. Also, if equation (2) is transformed,
d2x2 / dt2 = -k2 (x2-x1) / M2 (6)
(5) and (6),
m = [-k1 (x1-y) /-k2 (x2-x1)] M2 + M2-M1 (7)
Is derived.

  Here, -k1 (x1-y) is the output of force sensor 1, -k2 (x2-x1) is the output of acceleration sensor 4, but these outputs are not related to the mass, so robot The output of each sensor when the hand 2 accelerates without having anything is determined as a zero point, and then the span coefficient is calculated from these outputs when a weight having a known mass is given to the robot hand 2 and accelerated. You need to

FIG. 3 is a graph showing changes in output data of the force sensor 1 and the acceleration sensor 4 when the robot hand 2 is accelerated up and down in a no-load state to obtain a zero point. In this figure, when the peak value of the output data of the force sensor 1 is Fmz and the peak value of the output data of the acceleration sensor 4 is Faz, according to equation (7),
0 = M2 · C · (Fmz / Faz) + M2-M1 (8)
It becomes. However, it is assumed that Faz is not 0 and C is a conversion factor.

FIG. 4 is a graph showing changes in output data of the force sensor 1 and the acceleration sensor 4 when a weight of mass ms is held on the robot hand 2 and accelerated vertically. In this figure, when the peak value of the output data of the force sensor 1 is Fms and the peak value of the output data of the acceleration sensor 4 is Fas, according to equation (7),
ms = M2 · C · (Fms / Fas) + M2-M1 (9)
It becomes. And from (8), (9) formula,
C = ms / M2 {(Fms / Fas)-(Fmz / Faz)} (10)
Is derived. Moreover, since M2 is a constant according to equation (10), if the span coefficient is S,
S = C · M2 = ms / {(Fms / Fas)-(Fmz / Faz)} (11)
It becomes.

FIG. 5 is a graph showing changes in output data of the force sensor 1 and the acceleration sensor 4 when the robot hand 2 is caused to have an article Q of a mass m and accelerated vertically. In this figure, when the peak value of the output data of the force sensor 1 is Fm and the peak value of the output data of the acceleration sensor 4 is Fa, according to equation (11),
m = S {(Fm / Fa)-(Fmz / Faz)} (12)
It becomes. Therefore, the span coefficient S, the output (Fmz) of the force sensor 1 at no load, and the output (Faz) of the acceleration sensor 4 are obtained, and the output of the force sensor 1 when the robot hand 2 accelerates the article Q If (Fm) and the output (Fa) of the acceleration sensor 4 are detected, the mass m of the article Q can be measured.

  Here, the peak value of the output data of each sensor is adopted because there is a difference between the frequency characteristics of the force sensor and the acceleration sensor, which causes a phase shift in each output data. It is a measure to minimize it.

JP, 2013-079931, A JP, 2013-174503, A JP, 2013-174570, A JP, 2013-185846, A JP, 2013-185847, A JP, 2013-185848, A JP, 2013-195200, A

  As can be understood from the equation (12), if the span coefficient S and the zero point (Fmz / Faz) are obtained in advance, the force sensor 1 is moved even when the robot hand moves the article Q of a new unknown mass m. The mass m of the article Q can be obtained by detecting the output (Fm) of and the output (Fa) of the acceleration sensor 4 and substituting them into the equation (12).

  However, the zero may shift as time passes. For example, when deposits are deposited on the robot hand, the zero point is thereby offset. In addition, the span coefficient largely changes depending on the type of robot hand. For example, there are two types of robot hands: a finger type for gripping and lifting an article, and a type in which the article is adsorbed and held by a bellows-like rubber suction pad. When the latter suction pads are used to lift the articles, the suction pads expand and contract causing the articles to vibrate, thereby changing the vibration characteristics of each sensor. Therefore, each span coefficient differs between the case of using the finger type and the case of using the suction pad.

There are other factors that cause the span factor to shift. For example, if the acceleration for obtaining the span coefficient is different from the acceleration for actually measuring while transporting the article, the span coefficient is deviated. Furthermore, when using a suction pad, even if it moves with the same acceleration, if there is a difference in the suction force of the suction pad, its vibration characteristics change, and the span coefficient also shifts accordingly.
In addition, the span coefficient may be deviated depending on the item. For example, if the article is a bag-packed product or a bottle-packed product, the content moves when it is lifted and moved, and vibration is applied to each sensor, so the span coefficient determined for the solid even if the mass is the same And the span coefficient found for bagged products do not match.
Therefore, if the mass is measured without considering the difference, a measurement error occurs.

  The present invention is intended to solve the problems unique to mass measuring devices incorporated into such robots, and it is an object of the present invention to provide a new mass measuring device capable of minimizing measurement errors during operation. .

The mass measuring device according to the first invention is
A gripping mechanism for gripping an article;
A moving mechanism for moving the gripping mechanism;
A force sensor provided between the gripping mechanism and the moving mechanism for detecting a force acting on the article while the speed is changing;
An acceleration sensor for detecting an acceleration acting on the article while the speed is also changing;
Setting means for setting and registering the mass (m2) of the second article whose mass is known;
A first output (Fmz, Faz) is stored as the first output (Fmz, Faz) when the movement mechanism and the holding mechanism move while changing the speed of the holding mechanism without any movement. Output detection means;
Second output detection means for storing, as a second output (Fms, Fas), an output of each sensor when each mechanism is moving the second article while changing its speed;
When moved while changing the stored first output (Fmz, Faz) and second output (Fms, Fas), the mass m2 of the registered second article, and the speed of the article to be measured Calculating means for calculating the mass of the article based on the outputs (Fm, Fa) of the respective sensors detected in
Equipped with
The gripping mechanism measures the speed of the article to be measured lifted at the first position, changes the speed, transports it to the second position, then releases the article to change the speed from the second position to the first position. While repeating the operation,
The first output detection means detects the output of each of the sensors when returning from the second position to the first position while changing the speed in a state in which the gripping mechanism has nothing, based on the detected output. The first output is configured to be stored and updated.

  The first article here may be of zero mass. The fact that the mass is zero means that the gripping mechanism is moved under no load condition. In this case, zero is registered by the setting means. Although it is necessary to input the output of the same timing from each sensor, since the output of each sensor has a phase shift, the peak value of each output is detected and the influence is eliminated. Therefore, as the first output, the peak value (Fmz, Faz) of each output is detected and registered. Alternatively, or together with this, the ratio (Fmz / Faz) of each output may be registered. Similarly, the second output also registers the peak value (Fms, Fas) of each output. In the following description, the first output (Fmz, Faz or their ratio Fmz / Faz) and the second output (Fms, Fas), and the mass m1 of the first article and the mass m2 of the second article, span It may be said to be the basic data for determining the coefficient.

  When dealing with a new article or when the article type changes during the process, it is necessary to re-obtain basic data each time. When the basic data is to be recaptured, two articles of different weights are selected from the group of articles targeted, one of which is the first article and the other of which is the second article, their respective masses are measured by a precision balance or the like, The setting value is registered by setting means. When there is almost no difference in the mass of the two articles, the mass of the first article is set as zero and registered, and only the second article is used. However, when using a suction pad as a gripping mechanism, if the suction pad moves without adsorbing anything, it differs from the measurement conditions when the article is actually adsorbed, so in this case, Among them, the one with the smallest mass is selected as the first article, and the one with the largest mass is selected as the second article. When that is difficult, one article is taken as a first article, and a combination of two articles is registered as a second article.

By operating the moving mechanism and the gripping mechanism, first, the first article is gripped and moved while changing its speed. Since the output of each sensor is sequentially input during that time, the first output detection means detects the peak value of each output and registers it as the first output (Fmz, Faz).
Subsequently, the next second article is gripped and moved while changing its speed. Since the output of each sensor is sequentially input during that time, the second output detection means detects the peak value of each output and registers it as the second output (Fms, Fas).
Since basic data of the first output (Fmz, Faz) and the mass of the first article (zero or m1), and the second output (Fms, Fas) and the mass m2 of the second article have been set and registered, The span coefficient S can be calculated using the value.

  In this case, the operation mode of the moving mechanism or the like when measuring the first article and the operation mode when measuring the second article are made to coincide with each other. Furthermore, it is made to correspond also with the operation mode at the time of shifting to normal operation. Even if it is the same article, if the operation mode at the time of measurement changes, the basic data will be shifted, so it is moved in the same operation mode.

In the above description, when moving the first article and moving the second article, the moving mechanism and the gripping mechanism are operated and operated, but if this is operated once, the first article is moved first After that, the second article may be moved subsequently.
In addition, since the mass of the article is measured in the first step of moving it while accelerating it, there is no problem even if the subsequent operation is different each time. Therefore, if the first output is obtained in the first step, it may be treated as a normal article in the later step. The same applies to the second item. The process in this case is, for example, a process in which if the determined mass is normal, it is stored as it is in a packaging container or the like, and if it is a defective product such as light weight or excess, it is excluded out of the line.

In the above operation, first, the first article is accelerated to register the first output (Fmz, Faz), and then the second article is moved in the same process to register the second output (Fms, Fas). When the first article has a mass of zero, that is, when the first output is obtained without holding the gripping mechanism, the gripping mechanism can be reciprocated only once. For example, the second article is gripped first, moved while accelerating, and stored in a packing container or the like. Subsequently, it is operated to return to the original position in the same acceleration mode under no load condition. Then, the second output (Fms, Fas) is acquired in the first step of moving the second article while accelerating, and subsequently, the first output (Fmz, Faz) in the subsequent step of returning to the original position under no load condition. To get This makes it possible to acquire the first output and the second output in one reciprocating operation.
Such operation may be repeated a plurality of times, and the obtained first output and second output may be averaged to obtain basic data and span coefficients. This will further reduce the measurement error.

The second invention is
In the case where the output of each sensor at the time of returning from the second position while changing the speed from the second position to the first position is stored as a new first output when the first output detection means does not have any holding mechanism , Storing and updating the average value of the plurality of times of the first output.

The third invention is
The gripping portion is configured to be operated to return to the same position in the same operation mode when detecting the first output in the no-load state.

The above is the operation performed when handling different types of articles, when using different types of gripping mechanisms, or when the operation mode at the time of measurement is different. Can be made as small as possible. However, every time the type of article changes, it is a bothersome operation to recover the basic data for obtaining the span coefficient.
The following fourth invention is to eliminate such troublesomeness,
The first output (Fmz, Faz) and the second output (Fms, Fas), the mass m2 of the second article, or the span coefficient calculated therefrom, and the first output (Fmz, Faz or their ratio A first table in which Fmz / Faz) is stored in correspondence with the type of article to be measured;
An article designation unit for designating the type of article to be measured;
The first output (Fmz, Faz) and the second output (Fms, Fas) corresponding to the designated type of the article to be measured, and the mass m2 of the second article, or the span coefficient S and the first A reading means for reading one output (Fmz, Faz or their ratio Fmz / Faz) from the first table;
The calculation means is configured to calculate the mass of the article based on the read out data and the output of each sensor when holding and moving the designated measurement object. .

  Here, the span coefficient refers to the first output (Fmz, Faz or their ratio Fmz / Faz) and the second output (Fms, Fas), as well as the mass m1 of the first article and the mass m2 of the second article. The coefficient S is obtained by substituting it into equation (11) of However, ms in equation (11) is (ms = m2-m1). In addition, with regard to types of articles, articles whose basic data and span coefficients are shifted even if basic data and conditions are obtained under the same conditions are regarded as "articles of different types". For example, when the article is lifted, the article itself vibrates, and the bagged goods that change the vibration characteristics of the respective sensors and the solid that the article itself does not vibrate have the calculated basic data or the span calculated based thereon Since the coefficients are different, they are treated as articles of different types.

  The basic data acquired for each type of different articles, or the span coefficient S calculated based on the basic data and the first output are stored in the first table in correspondence with the types of articles, and the article designation unit If the type is specified, the corresponding basic data or span coefficient and the first output are read from the first table and set in the calculation means. Therefore, even if the item is switched to another type, simply by designating the item, the basic data, span coefficient, etc. corresponding to it are automatically set, and it is possible to immediately shift to normal operation.

By the way, although the moving mechanism and the gripping mechanism operate under the set control program, the control program may be changed halfway. In particular, if the operation mode at the time of measurement, that is, the operation of accelerating or decelerating while holding the article is changed, the span coefficient is shifted. In such a case as well, it is necessary to recover the basic data, but if you forget it, measurement errors will occur.
The following fifth invention is to prevent it,
Mode detection means for detecting a change in operation mode at the time of measurement;
The apparatus further comprises warning means for warning of the resumption of the mass m2 of the second article, the first output (Fmz, Faz) and the second output (Fms, Fas) when a change in operation mode is detected. It is characterized by

  If the operation is resumed without changing the basic data after the change of the control program, the mode detection means operates to check whether the operation mode at the time of measurement has been changed. For example, if the action program for lifting an article while holding it is accelerated after grasping the article, it will change the operation mode at the time of measurement, so compare the new and old of the operation program of that process, and both If it is different, it is determined that the operation mode has been changed. If it judges, operation | movement of a movement mechanism etc. will be stopped.

  Thus, when a change in the operation mode is detected, the warning means warns that the basic data should be recovered to obtain the span coefficient. The warning is given by, for example, displaying a message on the display unit or sounding a warning. When the operator confirms it, the basic data is reworked. The operation is as described above.

Incidentally, it is a bothersome operation to retrieve basic data every time the operation mode at the time of measurement changes. The following sixth invention is to eliminate such troublesome operation,
A second table storing the first table acquired each time the operation mode at the time of measurement changes in correspondence with each operation mode;
A mode designating means for designating the operation mode;
A display unit is provided for reading out and displaying the stored contents of a first table corresponding to a designated operation mode from the second table.

  When the operation mode at the time of measurement is changed, basic data is read again under the changed operation mode. The basic data acquired at that time, or the span coefficient and the first output are stored in the first table in correspondence with the type of the article. At the same time, the first table is stored in the second table in association with the changed operation mode, that is, linked to the operation mode. Then, when the operation mode is designated by the mode designation unit, the stored content of the first table registered under the designated operation mode is read and displayed on the display unit. When there are a plurality of types of displayed items, one of them is specified using the above-mentioned item specifying means. Then, the aforementioned reading means reads the basic data of the designated article, or the span coefficient S and the first output (Fmz, Faz or their ratio Fmz / Faz) from the first table in the second table, Set it to the calculation means. Therefore, after basic data is reworked under the changed operation mode, only by designating the operation mode, the stored contents of the corresponding first table are displayed, and an item is designated from among them. Since the basic data of the article or the span factor and the first output are automatically set, the subsequent operation becomes extremely easy.

By the way, in the case where the article is a bagged product or the like of a powdery substance, the adhering matter may be deposited on the gripping mechanism while the gripping mechanism repeatedly grips it. Such deposits overwhelm the value of the first output (Fmz, Faz or their ratio Fmz / Faz), and the measurement error becomes larger as time passes.
In order to eliminate the effects of such deposits,
The first output stored in the first table is updated with the first output of each sensor acquired when the gripping mechanism moves the article while releasing it and changing the speed.

  When the gripping mechanism releases the article, it is in a no-load state, and in that state, the gripping mechanism moves to change the speed, acquires the first output of each sensor, and uses the first output to obtain the old first output. By updating, even if deposits are deposited on the gripping mechanism, the influence of the deposits can be eliminated.

  According to the present invention, even when handling different types of articles, or when using different types of gripping mechanisms, changes in the operation mode at the time of measurement, or deposits on the gripping mechanisms, Even if one output is shifted, the measurement error can be minimized and more accurate mass can be measured.

The schematic block diagram for demonstrating the measurement principle of the mass measuring device which concerns on this invention. The figure showing the 2 degrees of freedom model which expressed the mass measurement apparatus of FIG. 1 with a spring-mass system. The graph which shows the output of each sensor when nothing is made to hold a holding mechanism. The graph which shows the output of each sensor when making a holding mechanism hold a known weight. The graph which shows the output of each sensor when making the holding | grip mechanism hold | maintain the goods of mass m. BRIEF DESCRIPTION OF THE DRAWINGS The schematic block diagram of the mass measuring device which concerns on one Embodiment of this invention. The schematic block diagram which shows an example of the holding | grip mechanism used by the said embodiment. The block diagram of 1st Embodiment. The schematic block diagram of the signal processing circuit which processes the output signal of each sensor. The block diagram of the principal part of a 2nd embodiment. The table showing an example of the memory contents of the 1st table. The table showing an example of the modification of the 1st table. The block diagram of the principal part of a 3rd embodiment. The block diagram of the principal part of a 4th embodiment. A table showing an example of a second table. The block diagram of the principal part of a 5th embodiment. The flowchart which shows an example of the basic motion of the said embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The following embodiments do not limit the technical scope of the present invention.

(1) Basic Configuration of Mass Measurement Device FIG. 6 shows a schematic configuration diagram of a mass measurement device 100 according to an embodiment of the present invention. In this figure, the mass measuring apparatus 100 includes a moving mechanism 11 as a robot arm, a force sensor 13 for detecting a force acting on an article Q in motion, and an acceleration sensor 14 for detecting an acceleration acting on the article Q. And a gripping mechanism 12 for gripping the article Q.

  The moving mechanism 11 is a robot arm that moves the gripping mechanism 12 in a three-dimensional manner, and one end of a force sensor 13 is fixed to the distal end base portion 15 thereof. As the moving mechanism 11, for example, a horizontal articulated robot, a vertical articulated robot, a parallel link robot, or the like can be adopted.

  For example, a strain gauge type load cell is adopted as the force sensor 13. In the strain gauge type load cell, the free end is displaced relative to the fixed end by the load of the article Q, and the displacement amount detects the force applied to the free end. Further, an acceleration sensor 14 and a gripping mechanism 12 are provided on the free end side of the force sensor 13.

  As the acceleration sensor 14, for example, in addition to a strain gauge type load cell, any of a MEMS type small acceleration sensor and a general commercially available acceleration sensor may be appropriately employed.

  The gripping mechanism 12 is a robot hand that grips the article Q. Although the holding mechanism 12 of FIG. 6 shows an example of a finger type, it can replace with this and can adopt an air adsorption type which carries out adsorption holding of the article Q by negative pressure as shown in FIG. The finger type of FIG. 6 is suitable when the article Q is a solid, and the air adsorption type of FIG. 7 is suitable for the non-uniform shape, for example, a bagged product.

  FIG. 7 shows a schematic configuration diagram of the air adsorption type. In this type, a bellows-like suction pad P made of silicon rubber is attached to a box B made of aluminum, and the suction pad P and the inside of the box B are communicated. By holding the inside of the aluminum box B at a negative pressure, the articles Q are adsorbed and held by the respective suction pads P. In addition, since the plurality of articles Q may be simultaneously gripped by a large number of suction pads P, the number, shape, arrangement, and the like of the suction pads are appropriately changed according to the type of the article Q. Therefore, a plurality of types of gripping mechanisms 12 are prepared according to the type of the article Q, and these are used properly according to the type of the article Q.

(2) Basic Configuration of Control System <First Embodiment>
FIG. 8 is a block diagram of a control system of the mass measuring device 100 according to the first embodiment. In this figure, the movement mechanism 11, the holding mechanism 12, the force sensor 13, the acceleration sensor 14, the operation unit 20, and the display unit 30 are electrically connected to the control substrate 60 having the storage unit 40 and the control unit 50. There is.

The operation unit 20 is configured of a keyboard, a touch panel, and the like, and can operate the moving mechanism 11 and the holding mechanism 12 in various operation modes if the control program is activated to operate the operation program. Moreover, the port etc. which output the mass of each measured goods to an external memory are also provided.
The operation unit 20 is provided with setting means 21 for setting and registering each mass (m1, m2) of the first article and the second article and an operation key 22.
The setting means 21 sets and registers the mass (m1) of the first article and the mass (m2) of the second article in the storage unit 40 when calculating the span coefficient, and sets these masses (m1, m2) A key to be input and a confirmation key for registering the input numerical value in the storage unit 40 are provided.
The operation key 22 operates the moving mechanism 11 and the holding mechanism 12. When the operation key 22 is operated, the first article or the second article is conveyed in the same operation mode as the operation mode for the normal article. In this operation mode, for example, “grasp mechanism 12 grips article Q, lifts it horizontally while accelerating it at 50% ability to point A, moves horizontally, and when it reaches point B, decelerates from there by 40% ability While moving down to store the article Q in the packing container.

  The display unit 30 is a device for displaying an operation state of the mass measuring apparatus 100, a field for inputting the respective masses (m1, m2), and an operation guide. According to the operation guide, the mass (m1) of the first article and the mass (m2) of the second article are input in the displayed column, and when the enter key is pressed, they are set and registered in the storage unit 40. In addition, when the operation mode at the time of measurement is changed, a message or the like prompting to re-acquire basic data is displayed.

  The storage unit 40 includes a control program for moving the moving mechanism 11 and the gripping mechanism 12 in a predetermined operation mode, an operation guide for obtaining basic data, and the respective masses of the first and second articles (m1,. m2), the first output (Fmz, Faz or its output Fmz / Faz) and the second output (Fms, Fas) fetched from the respective sensors 20, 21 are stored as basic data. Further, a first table 41 described later which stores the basic data or the span coefficient S calculated based thereon and the first output (Fmz, Faz or their ratio Fmz / Faz) in association with the type of the second article And the second table 42 are stored.

  The control unit 50 is constituted by a microcomputer, and operates the moving mechanism 11 and the gripping mechanism 12 in a predetermined operation mode by reading out and executing various programs stored in the storage unit 40. Also, the outputs of the force sensor 13 and the acceleration sensor 14 are sequentially input in synchronization with these movements, and they are input to a DSP (digital signal processor) (not shown) for filtering processing. Furthermore, by reading and executing the program stored in the storage unit 40, a first output detecting unit 51, a second output detecting unit 52, a span coefficient calculating unit 53, an operating unit 54, a reading unit 55, and a mode detecting unit are described later. Each function such as 56, updating means 57 etc. is realized.

  When the operation key 22 is operated, the moving mechanism 11 and the holding mechanism 12 operate to hold the first article and accelerate and move it while lifting it, but the first output detection means 51 sequentially inputs The peak value of the output of each of the detected sensors 13 and 14 is detected and stored in the storage unit 40 as a first output (Fmz, Faz).

  Similarly, when the operation key 22 is operated, the mechanisms 11 and 12 operate to grip the second article and accelerate it to move it while lifting it, but the second output detection means 52 is input between them The peak value of the output of each sensor 13, 14 is detected and stored in the storage unit 40 as the second output (Fms, Fas).

  The span factor calculation means 53 stores the stored basic data, that is, the first output (Fmz, Faz or the ratio of those outputs Fmz / Faz) and the second output (Fms, Fas), and the mass m1 of the first article And the mass m2 of the second article is substituted into the equation (11) to calculate the span coefficient S, and this is stored in the storage unit 40.

  The calculating means 54 calculates the span coefficient S and the stored first output (Fmz, Faz or their ratio Fmz / Faz), and each sensor 13 detected when moving while changing the speed of the article Q, The mass of the article Q is calculated based on the 14 outputs (Fm, Fa). The peak values of the outputs (Fm, Fa) of the respective sensors 13, 14 at this time are adopted.

  FIG. 9 shows an example of a signal processing circuit diagram for processing the outputs of the force sensor 20 and the acceleration sensor 21. As shown in FIG. In FIG. 9, A / D converters 23a and 23b are connected to the force sensor 20 and the acceleration sensor 21 via amplifiers 22a and 22b, respectively. The A / D converters 23 a and 23 b convert the input analog signal into a digital signal and input it to the control unit 50.

  The control unit 50 performs a filtering process in the DSP (digital signal processor) based on the input output. For example, noise frequency components included in the outputs of the sensors 13 and 14 are removed by a low pass filter. Subsequently, the first output detection means 51 and the second output detection means 52 respectively detect the respective peak values from the series of outputs from which the noise component has been removed.

Second Embodiment
FIG. 10 shows a configuration block diagram of the main part of the second embodiment. In FIG. 10, the storage unit 40 stores a first table 41 as shown in FIG.
The first table 41 includes the mass m1 of the first article and the mass m2 of the second article, and the first outputs (Fmz, Faz) and the first according to the type of article (specified by the numbers No. 1 to N0.3). It stores two outputs (Fms, Fas), a span coefficient S calculated from those values, and a ratio of the first output (Fmz / Faz). In this case, an air suction type A is used as the gripping mechanism 12.
Also, if the type of the gripping mechanism 12 is different, the basic data or the span coefficient calculated based on the basis data is different. Therefore, as shown in FIG. 12, the type of the gripping mechanism 12 (type It may correspond to A, Type B, Type C).

When basic data (Fmz, Faz, Fms, Fas, mass m1, mass m2) is registered in the first table 41, the mass measuring apparatus 100 is switched to the setting mode. Then, since the input screen is displayed on the display unit 30, the type of the gripping mechanism 12 and the type of the article are input in predetermined columns of the screen. For example, type A etc. is input for the gripping mechanism 12, and a number etc. is input for the article.
Next, the mass m1 of the first article selected from the article group is input to a predetermined field of the input screen, and the enter key is pressed. Then, the input mass m1 is registered in a predetermined column of the first table 41. Subsequently, the mass m2 of the second article is input in a predetermined field, and the enter key is pressed. Then, it is similarly registered in a predetermined field of the first table 41.

Next, when the operation key 22 is operated, the set control program is executed to operate the moving mechanism 11 and the gripping mechanism 12 to first grip the first article, lift it and move it while accelerating. . Since the outputs of the sensors 13 and 14 are sequentially input to the control unit 50 during that time, the first output detection means 51 detects the peak value of each output and uses it as the first output (Fmz, Faz) as the first table. Store in 41
Subsequently, when the test operation key 22 is operated, the moving mechanism 11 and the gripping mechanism 12 similarly operate to move the next second article while changing its speed. Since the outputs of the sensors 13 and 14 are sequentially input during that time, the second output detection means 52 detects the peak value of each output and stores it as the second output (Fms, Fas) in the first table 41. .

  The article designation unit 23 designates the type of article to be measured from the stored contents of the first table 41 displayed on the display unit 30, and is provided in the operation unit 20, and operates the second article to operate it. If the type of is specified, the reading means 55 operates to read out the basic data of the specified article or the span coefficient S and the first output (Fmz, Faz or their ratio Fmz / Faz) from the first table 41. The designation of the article can be designated, for example, by touching the displayed article name, number or the like.

  Since the basic data read out in this way, or the span coefficient S and the first output (Fmz, Faz or their ratio Fmz / Faz) are set in the computing means 54, the article to be measured is gripped When the outputs (Fm, Fa) of the respective sensors 13, 14 when moved are obtained, the computing means 54 sets the basic data set or the span coefficient S and the first output (Fmz, Faz or their ratio Fmz Calculate the mass of the article based on / Faz) and the output (Fm, Fa).

Third Embodiment
FIG. 13 shows a configuration block diagram of the main part of the third embodiment. In FIG. 13, the storage unit 40 stores a plurality of control programs for operating the moving mechanism 11 and the gripping mechanism 12 in a predetermined operation pattern. Then, when the operation unit 20 is operated and the control program is read, the read control program is set, and when the operation start key (not shown) is operated, the moving mechanism 11 and the grip are held based on the set control program. The mechanism 12 operates. At this time, if the set control program is changed halfway, the mode detection means 56 checks whether the operation mode at the time of measurement has been changed, and if it has been changed, basic data for the warning means 31 Instruct them to warn you to

  The warning means 31 is provided in the display unit 30, and warns of the resumption of basic data based on the instruction of the mode detection means 56. The warning is displayed, for example, by displaying a message on the display unit 30 or by making a warning sound. When this warning is displayed, the operator performs basic data recovery under the new operation mode.

Fourth Embodiment
FIG. 14 shows a configuration block diagram of the main part of the fourth embodiment. In FIG. 14, the storage unit 40 stores a second table 42 as shown in FIG. 15. The second table 42 stores the first table acquired each time the operation mode at the time of measurement changes in association with each operation mode.

  For example, assuming that the first table 41 shown in FIG. 11 is the basic data for each item acquired under the original operation mode, or the span coefficient and the first output, the second table in FIG. The mode is changed to mode 1, and under the mode 1, basic data or one obtained by retaking the span coefficient and the first output again is stored in association with the operation mode 1. Similarly, in modes 2 and 3 as well, the basic data etc. are recaptured under modes 2 and 3 and stored in correspondence to the respective operation modes 2 and 3.

  The mode designation unit 24 designates one of these operation modes, and for example, designates the operation mode number of the second table displayed on the display unit 30 by touching. Then, the first table 41 registered under the designated operation mode is read by the reading means 55 described above and displayed on the display unit 30.

When the first table 41 is displayed, the article designation unit 23 designates an article to be measured. For example, the user designates by touching an item designated from among the items displayed on the display unit 30. Then, the reading means 55 reads out the basic data of the designated article or the span coefficient S and the first output (Fmz, Faz or their ratio Fmz / Faz) from the first table 41 and sets them in the calculating means 54.
On the other hand, when the operation mode is designated by the mode designation means 36, the corresponding control program is read from the storage unit 40 and is set in the moving mechanism 11 and the gripping mechanism 12 and is operated by the operation start key. It is driven in the operation mode of

Fifth Embodiment
FIG. 16 shows a configuration block diagram of the main part of the fifth embodiment. In FIG. 16, the updating means 57 updates the first output (Fmz, Faz or their ratio Fmz / Faz, hereinafter this ratio is referred to as a zero point) of the first table 41 stored in the storage unit 40. In particular, in normal operation, for example, when the gripping mechanism 12 lifts the article Q, moves it while accelerating it to carry it into the packaging container, and then repeats the operation of picking up the new article Q again. When carrying the article Q into the packaging container and returning to the original position, the gripping mechanism 12 is unloaded. In this state, the outputs of the sensors 13, 14 are sequentially input, their peak values are detected as zeros, and old zeros of the first table 41 are stored and updated with the zeros.

  This updating means 57 may detect and update the zero point every time the gripping mechanism 12 is unloaded, or may update it once in a plurality of times. Alternatively, the old zero may be updated after obtaining the average value of the plurality of zeros.

  Next, the basic operation of the mass measuring device 100 will be described based on the flowchart of FIG.

  Since this mass measuring apparatus 100 can be incorporated into an existing robot later, several operation modes for gripping and moving an article have already been registered as mode 1, mode 2, etc. in this robot I assume. When operating the mass measuring apparatus 100 incorporated in such a robot, first, the second table 42 is displayed on the display unit 30 (step S1), and the operation mode to be operated is selected from them (step S2).

Then, the content of the first table 41 corresponding to the selected operation mode is displayed on the display unit 30 (step S3). However, since nothing is registered at first, the item name and the number of the item to be registered are entered in the item type column of the first table 41 to specify the item.
Next, two articles having different weights are selected from the group of articles to be registered, and one of them is used as the second article as the first article residue, and the respective masses are measured by a precision balance or the like. Subsequently, the mass (m1, m2) of each article is input using the setting means 21, and each time the enter key is pressed (step S4). Then, the mass of each article is sequentially registered in the first table 41 (step S5).

  Next, when the operation key 33 is operated (step S6), the gripping mechanism 12 grips the first article, and the moving mechanism 11 transports it while changing the speed in the same operation mode as the ordinary article. Since the output of each sensor 13 and 14 is sequentially input during that time, the first output detection means 51 detects the peak value of each input that is input, and stores it as the first output (Fmz, Faz) as the storage unit 40. (Step S7). Subsequently, the second article is gripped and conveyed while changing the speed in the same operation mode as the first article. Since the output of each sensor 13 and 14 is sequentially input during that time, the second output detection means 52 detects the peak value of each input that is input, and stores it as the second output (Fms, Fas) in the storage unit 40. (Step S8).

  After the above basic data is registered, the span coefficient calculation means 53 operates to register the registered first output (Fmz, Faz or the ratio of those outputs Fmz / Faz) and the second output (Fms, Fas), Also, the span coefficient S is determined by substituting the mass m1 of the first article and the mass m2 of the second article into the equation (11), and this is registered in the storage unit 40 (step S9).

  Although the data registration of the first table 41 and the second table 42 is now completed, when the operation mode is switched to another mode and the span coefficient is determined in the same procedure as described above, the first table 41 and the 2 Data registration of the table 42 is performed. Thus, when the data registration of the first and second tables 41 and 42 is completed, it is possible to shift to the normal operation.

  In the normal operation, first, the operation unit 20 is operated to display the second table 42 on the display unit 30 (step S10), and an operation mode to be operated is selected from among them (step S11). Then, the control program of the corresponding operation mode is read and set in the moving mechanism 11 or the gripping mechanism 12 (step S12).

  Next, the first table 41 is displayed on the display unit 30 (step S13), and the type of article to be measured is designated by the article designation unit 23 (step S14). Then, the basic data of the corresponding article, or the span coefficient and the first output are read out and set in the calculation means 54 (step S15). Then, when the operation key is operated (step S16), the moving mechanism 11 and the gripping mechanism 12 are drive-controlled in a predetermined operation mode, and the article is moved while changing its speed (step S17). During that time, the output of each sensor is input, each peak value is detected, and they are stored in the storage unit 40. Then, the computing means 54 detects the stored basic data, or the span coefficient S and the first output (Fmz, Faz or their ratio Fmz / Faz), as well as when moving the article Q while changing the speed The mass of the article is calculated based on the outputs (Fm, Fa) of the sensors 13 and 14. The calculated mass is stored in the storage unit 40 and used for the processing of the post process (step S18). The mass of each item thus stored is output and used outside.

Such processing is continued until the articles are exhausted (steps S17 to S19), and when the articles are not sent to the predetermined position, the series of operations is finished.
There are two types of robots, a type in which a camera is mounted and a product is grasped while checking the position of the product, and a type in which an article sent to a predetermined position is mechanically gripped, although either type is applicable.

  As described above, according to the present invention, since the mass of an article can be measured more accurately while moving the article with a robot hand, the present invention can be widely used in the field of using industrial robots.

11 moving mechanism 12 gripping mechanism 13 force sensor 14 acceleration sensor 20 operation unit 21 setting means 22 operation key 23 article specifying means 24 mode specifying means 30 display unit 31 warning means 40 storage unit 41 first table 50 control unit 51 first output detection Means 52 second output detection means 53 span coefficient calculation means 54 operation means 55 readout means 56 mode detection means 57 update means Q article

Claims (6)

A gripping mechanism for gripping an article;
A moving mechanism for moving the gripping mechanism;
A force sensor provided between the gripping mechanism and the moving mechanism for detecting a force acting on the article while the speed is changing;
An acceleration sensor for detecting an acceleration acting on the article while the speed is also changing;
Setting means for setting and registering the mass (m2) of the second article whose mass is known;
A first output (Fmz, Faz) is stored as the first output (Fmz, Faz) when the movement mechanism and the holding mechanism move while changing the speed of the holding mechanism without any movement. Output detection means;
Second output detection means for storing, as a second output (Fms, Fas), an output of each sensor when each mechanism is moving the second article while changing its speed;
When moved while changing the stored first output (Fmz, Faz) and second output (Fms, Fas), the mass m2 of the registered second article, and the speed of the article to be measured Calculating means for calculating the mass of the article based on the outputs (Fm, Fa) of the respective sensors detected in
Equipped with
The gripping mechanism measures the speed of the article to be measured lifted at the first position, changes the speed, transports it to the second position, then releases the article to change the speed from the second position to the first position. While repeating the operation,
The first output detection means detects the output of each of the sensors when returning from the second position to the first position while changing the speed in a state in which the gripping mechanism has nothing, based on the detected output. A mass measuring device for storing and updating the first output.   In the case where the first output detection means stores and updates the outputs of the respective sensors at the time of returning from the second position to the first position while changing the speed in the state where the grip mechanism has nothing, as the new first output The mass measuring device according to claim 1, wherein the memory is updated by averaging the plurality of times of the first output. The mass measuring device according to claim 1 or 2, wherein the gripping mechanism is operated to return to the same position in the same operation mode when detecting the first output in the state of having nothing . The first output (Fmz, Faz) and the second output (Fms, Fas), the mass m2 of the second article, or the span coefficient calculated therefrom, and the first output (Fmz, Faz or their ratio A first table in which Fmz / Faz) is stored in correspondence with the type of article to be measured;
An article designation unit for designating the type of article to be measured;
The first output (Fmz, Faz) and the second output (Fms, Fas) corresponding to the designated type of the article to be measured, and the mass m2 of the second article, or the span coefficient S and the first A reading means for reading one output (Fmz, Faz or their ratio Fmz / Faz) from the first table;
The computing means is characterized in that the mass of the article is calculated based on the read out data and the output of each sensor when gripping and moving the designated article to be measured. The mass measuring device according to any one of claims 1 to 3. Mode detection means for detecting a change in operation mode at the time of measurement;
The apparatus further comprises warning means for warning of the resumption of the mass m2 of the second article, the first output (Fmz, Faz) and the second output (Fms, Fas) when a change in operation mode is detected. The mass measuring apparatus of any one of Claims 1-4. A second table storing the first table acquired each time the operation mode at the time of measurement changes in correspondence with each operation mode;
A mode designating means for designating the operation mode;
5. The mass measuring device according to claim 4 , further comprising a display unit for reading out and displaying the stored content of the first table corresponding to the specified operation mode from the second table.

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