Patent Description:
A work robot that includes a robot arm including a plurality of arm members is known in the related art. Document <CIT> discloses, for example, a funnel-shaped suction member having an opening for sucking in external air and holding a workpiece by suction, in which a conductive wire for detecting breakage due to disconnection is provided around the opening. However, in the suction member disclosed in Document <CIT>, it is necessary to manufacture a dedicated pad, and thus there is the problem that the suction member has no versatility.

Document <CIT> discloses a robot including an end effector provided with a pressure sensor that detects a suction pressure of a suction pad. In the robot disclosed in Document <CIT>, it is necessary to accurately detect a change in pressure up to when the suction is completely performed, and thus it is not possible to accurately detect the degree of wear of the suction pad.

Document <CIT> discloses a vacuum gripping device comprising at least one suction cup comprising at least one electrically conductive track secured to a skirt of the suction cup, wherein the conductive track is made of an elastically conductive and elastically deformable material to deform with the skirt. An electronic processing circuit is electrically connected to the conductive track and is arranged to monitor an electrical property of the conductive track. The electrical property varies with the deformation of the conductive track, and it is compared to reference data so as to anticipate a failure of the suction cup.

Document <CIT> discloses a deterioration judgement method of a teat cup liner, wherein a degree of deterioration of a teat cup liner is me assured by placing a measuring tool in contact with the teat insertion opening of the teat cup liner to bring the teat cup unit into a milking state and measuring the flow velocity at which the measuring tool collapses during the massage period of the teat cup liner.

Document <CIT> discloses a liner deterioration confirmation method for determining a degree of deterioration, wherein a vacuum pressure source of a milking machine is operated with a rod-shaped measuring device in contact with a lip opening of a teat cup liner to draw in the teat cup liner.

An aspect of the present invention has been made in view of the above problems, and an object of the present invention is to provide a suction apparatus capable of easily determining whether or not a suction portion has deteriorated.

A deterioration determination apparatus according to an aspect of the present invention includes: a deformation information obtainment unit configured to obtain information on deformations of a suction portion occurring when the suction portion sequentially holds a plurality of objects having different masses by suction, which suction portion is configured to hold an object by suction with negative pressure and elastically deforms by the negative pressure; and a deterioration determination unit configured to determine whether the suction portion has deteriorated, depending on whether or not the deformations of the suction portion occurring when the suction portion sequentially holds the plurality of objects by suction are within normal ranges set for the respective objects.

According to the above configuration, it is possible to set a normal range of the deformation of the suction portion, by obtaining in advance information on the deformation of the suction portion in a normal state under a predetermined condition. As a result, it is possible to determine whether or not the suction portion has deteriorated, in accordance with the degree of the deformation of the suction portion. Information on the deformation of the suction portion can be obtained using a sensor, for example. Accordingly, the deterioration determination apparatus can easily determine whether or not the suction portion has deteriorated.

According to the above configuration, because it is determined whether or not the suction portion has deteriorated depending on the deformations of the suction portion occurring when the suction portion sequentially holds the plurality of objects having different masses by suction, it is possible to more appropriately determine whether or not the suction portion has deteriorated.

According to an embodiment of the present invention, it is possible to easily determine whether a suction portion has deteriorated.

The deterioration determination apparatus may further include a lifetime prediction unit configured to predict a lifetime of the suction portion, depending on a temporal change of the deformation of the suction portion occurring when the suction portion holds the object by suction.

According to the above configuration, the user can replace the suction portion at an appropriate timing. In addition, the user can schedule maintenance of the deterioration determination apparatus.

The deterioration determination unit may specify a value representing a spring constant of the suction portion, from the deformation of the suction portion occurring when the suction portion holds the object having a known mass by suction with a predetermined negative pressure, and determine whether or not the suction portion has deteriorated, depending on the value representing the spring constant.

According to the above configuration, it is possible to appropriately determine whether or not the suction portion has deteriorated, by assuming the suction portion as a spring.

The deformation information obtainment unit may obtain information on deformations of the suction portion occurring when the suction portion sequentially holds a plurality of objects having different masses by suction, and the deterioration determination unit may specify a value representing a spring constant of the suction portion, from the deformations of the suction portion occurring when the suction portion sequentially holds the plurality of objects by suction with one or more predetermined negative pressures, and determine whether or not the suction portion has deteriorated, depending on the value representing the spring constant.

The deformation information obtainment unit may obtain information on deformations of the suction portion occurring when the suction portion sequentially holds the object by suction with a plurality of negative pressures, and the deterioration determination unit may determine whether or not the suction portion has deteriorated, depending on the deformations of the suction portions occurring when the suction portion sequentially holds the object by suction with the plurality of negative pressures.

According to the above configuration, because it is determined whether or not the suction portion has deteriorated based on the deformations of the suction portion occurring when the suction portion sequentially holds the object by suction with the plurality of negative pressures, it is possible to more appropriately determine whether or not the suction portion has deteriorated.

A deterioration determination method according to an aspect of the present invention includes: a deformation information obtainment step of obtaining information on deformations of a suction portion occurring when the suction portion sequentially holds a plurality of objects having different masses by suction, which suction portion is configured to hold an object by suction with negative pressure and elastically deforms by the negative pressure; and a deterioration determination step of determining whether the suction portion has deteriorated, depending on whether or not the deformations of the suction portion occurring when the suction portion sequentially holds the plurality of objects by suction are within normal ranges set for the respective objects.

The deterioration determination apparatus according to the aspects of the present invention may be achieved by a computer. In this case, the scope of the present invention may also include a control program for the deterioration determination apparatus that causes a computer to operate as the deterioration determination apparatus by causing the computer to operate as the units (software elements) included in the deterioration determination apparatus, and a computer-readable recording medium that records the control program.

Hereinafter, an embodiment according to one aspect of the present invention (hereinafter, also referred to as "the present embodiment") will be described with reference to the drawings.

<FIG> is a block diagram schematically showing an example of the configuration of a suction system <NUM> according to the present embodiment. The suction system <NUM> includes a suction apparatus <NUM>, a controller <NUM>, a deterioration determination apparatus <NUM>, a display unit <NUM>, and a sound output unit <NUM>. The suction apparatus <NUM> holds an object W by suction with negative pressure. The controller <NUM> controls the movement of the suction apparatus <NUM>. The deterioration determination apparatus <NUM> obtains information on deformation occurring in the suction portion <NUM>, and determines whether or not the suction portion <NUM> has deteriorated. The display unit <NUM> and the sound output unit <NUM> inform whether or not the suction portion <NUM> has deteriorated.

<FIG> illustrates the definition of the deformation amount of the suction portion <NUM> that is used in one embodiment of the present invention. Reference numeral <NUM> denotes a state in which the suction apparatus <NUM> does not holds the object W by suction. Reference numeral <NUM> denotes a state in which the suction apparatus <NUM> holds the object W by suction. The proximity sensor <NUM> measures a distance to a predetermined location in the suction portion <NUM>. Here, for example, a vector N perpendicular to the surface of the body <NUM> on which the proximity sensor <NUM> is provided is considered. In this case, a distance from the proximity sensor <NUM> to a point at which a straight line that is parallel to the vector N and passes through the proximity sensor <NUM> intersects the upper portion of the suction portion is defined as the distance from the proximity sensor <NUM> to the suction portion.

However, when a capacitive proximity sensor or a strain sensor that does not directly output a distance is used, a correspondence relationship between a measurement value of the sensor (information indicating a degree of deformation) and a distance is stored in the storage unit <NUM> in advance, as a table or a relational expression. In this case, the distance that corresponds to the measurement value of the sensor stored in the above table or obtained from the relational expression is set as the distance from the proximity sensor <NUM> to the suction portion.

A distance from the proximity sensor <NUM> to the suction portion <NUM> in a state denoted by the reference numeral <NUM> (that is to say, in a state in which the suction portion <NUM> does not hold the object W by suction) is denoted by d0, and a distance from the proximity sensor <NUM> to the suction portion <NUM> in a state denoted by the reference numeral <NUM> (that is to say, in a state in which the suction portion <NUM> is holding the object W by suction) is denoted by d. Here, the deformation amount Δd of the suction portion <NUM> is represented by d0-d. In the state denoted by the reference numeral <NUM>, the suction portion <NUM> is elastically deformed by negative pressure, and is in intimate contact with the object W.

Next, the relationship between the deformation amount Δd and the spring constant k will be described.

<FIG> shows a relationship between forces acting on the object W, when the suction portion <NUM> that is used in one embodiment of the present invention holds an object W that has a known mass.

The gravity acting on the object W and the restoring force by the suction portion <NUM> act on the object W in the vertically downward direction, and the suction force due to the negative pressure acts on the object W in the vertically upward direction.

Here, assuming that the mass of the object W is "M" and the gravitational acceleration is "g", the magnitude of the gravitational force acting on the object W is represented by "Mg". In addition, in a case where the elastically deforming suction portion <NUM> is assumed to be a spring, the spring constant of the suction portion <NUM> is defined as "k". By using the deformation amount Δd described above, the restoring force by the suction portion <NUM> can be expressed as "kΔd". Furthermore, when the pressure inside the suction portion <NUM> is P [atm], the suction area (the area of the object W to which the negative pressure is applied) is S, and the atmospheric pressure is <NUM> atm, the suction force generated due to the negative pressure can be expressed as (<NUM>-P)S. At this time, in order for the suction portion <NUM> to continuously hold the object W by suction, the following force balance must be satisfied.

Here, the mass M, the pressure P, and the suction area S of the object W are known values. Accordingly, the value of the spring constant k can be specified, by measuring the deformation amount Δd of the suction portion <NUM>. Note that, instead of the actual spring constant, it is also possible to specify a value that is determined unambiguously from the spring constant (for example, a value of M/Δd, which is obtained when the suction force is assumed to be constant) as a "value representing the spring constant". Specifying the spring constant is substantially synonymous with specifying a "value representing the spring constant", which is determined unambiguously from the spring constant.

The suction portion <NUM>, which contains rubber and the like, becomes hard when the suction portion deteriorates, and thus the value of the spring constant k increases. Also, the value of k varies (e.g., the value of k decreases), when the mechanical structure of the suction pad changes due to cracking, wear, breakage, or the like.

For this reason, a normal range of the spring constant k is set in advance. When the spring constant k crosses a threshold value indicating an upper limit or a lower limit of the normal range, the deterioration determination apparatus <NUM> determines that the suction portion <NUM> has deteriorated. In addition, when the mass M and the pressure P of the predetermined object W are known, the normal range of the deformation amount Δd can be set in advance.

<FIG> is a block diagram showing a configuration of the suction system <NUM> according to the present embodiment. The suction system <NUM> includes a suction apparatus <NUM>, a controller <NUM>, a deterioration determination apparatus <NUM>, a display unit <NUM>, and a sound output unit <NUM>. In the present embodiment, the suction apparatus <NUM> may be a fixed suction apparatus that is fixed at a predetermined position, or may also be a movable suction apparatus including an automated guided vehicle.

In the example of <FIG>, the suction apparatus <NUM> includes a sensor assembly <NUM>, a suction portion (suction pad) <NUM>, and a shaft <NUM>. An air passage for sucking in air is formed in the shaft <NUM>. The air passage is connected to the suction portion <NUM> and a tube <NUM>. The shaft <NUM> and a vacuum pump that generates negative pressure may be connected through the tube <NUM>. The suction portion <NUM> of the suction apparatus <NUM> may be grounded.

Because the suction portion <NUM> is disposed on one end side of the shaft <NUM>, the sensor assembly <NUM> is preferably attached to the shaft <NUM> on the other end side of the shaft <NUM>, for example. However, in order to accurately detect the deformation of the suction portion <NUM>, a body <NUM> is preferably disposed at a position close to the suction portion <NUM>, for example.

A support portion <NUM> of a fixture <NUM> extends from a fixed portion <NUM> toward the suction portion <NUM>. The body <NUM> is disposed on a suction portion <NUM> side relative to the fixed portion <NUM>, using the support portion <NUM>. With this configuration, it is possible to fix the fixture <NUM> to the other end side (the opposite side to the suction portion <NUM>) of the shaft <NUM>, and to dispose the sensor assembly <NUM> at a position close to the suction portion <NUM>.

The sensor assembly <NUM> includes the body <NUM>, one or more proximity sensors <NUM>, and the fixture <NUM>.

A space <NUM> (not shown) through which the shaft <NUM> of the suction apparatus <NUM> passes is formed in the body <NUM>. The space <NUM> may be a hole, or a notch. The main body <NUM> is not in contact with the shaft <NUM>, for example. The body <NUM> may have a circular shape, a quadrangular shape, or an elliptical shape. In addition, the space <NUM> may have a circular shape, a quadrangular shape, or an elliptical shape. The body <NUM> and a controller such as a programmable logic controller (PLC) or the deterioration determination apparatus <NUM> may be connected through a sensor wiring <NUM>.

In the example 1a in <FIG>, the proximity sensor <NUM> is disposed on the main body <NUM> along the circumferential direction of the space <NUM> (the shaft <NUM>). In the example 1b in <FIG>, a plurality of the proximity sensors <NUM> are disposed on the body <NUM> along the circumferential direction of the space <NUM> (the shaft <NUM>). In the example 1c in <FIG>, a plurality of the proximity sensors <NUM> are disposed on the body <NUM> along the circumferential direction and the radial direction with respect to the space <NUM> (the shaft <NUM>). In the example 1d in <FIG>, the space <NUM> has a quadrangular shape, and the proximity sensor <NUM> is disposed on the body <NUM> having a quadrangular outer shape. In the example 1e in <FIG>, the space <NUM> has a circular shape, and the proximity sensor <NUM> is disposed on the body <NUM> having a quadrangular outer shape. In the example 1f in <FIG>, the proximity sensor <NUM> is disposed on a quadrangular body <NUM> in which the space <NUM> has a circular shape. In the example <NUM> in <FIG>, the proximity sensor <NUM> is disposed on an elliptical body <NUM> in which the space <NUM> has an elliptical shape. In the example <NUM> in <FIG>, a plurality of the proximity sensors <NUM>, which are sensor chips, are disposed on the body <NUM> along the circumferential direction of the space <NUM> (the shaft <NUM>).

The suction portion <NUM> is elastically deformed. The suction portion <NUM> includes an elastic member, e.g. made of rubber. The suction portion <NUM> may be a nonconductive pad, but when the suction portion <NUM> is a conductive pad, the deformation amount of the suction portion <NUM> can be detected with high accuracy. A conductive pad (a pad for electrostatic diffusion or a pad that can be detected by metal detection) is suitable for the detection method disclosed in the present embodiment, because a conductive material such as metal is contained in the pad. When the suction portion <NUM> comes into contact with an object and the suction portion <NUM> is further pushed into the object, the electrostatic capacitance detected by the capacitive proximity sensor <NUM> increases rapidly. This is because the proximity sensor <NUM> and the conductive member of the suction portion <NUM> approach each other, as the suction unit <NUM> is pushed into the object. Therefore, when the suction portion <NUM> includes a conductive member at a displaced position and at least one of the proximity sensors <NUM> is a capacitive sensor, the deformation amount of the suction portion <NUM> can be accurately detected regardless of the dielectric constant of an object (workpiece).

The suction apparatus <NUM> includes a manipulator unit <NUM>, a suction portion <NUM>, a vacuum pump <NUM>, a proximity sensor <NUM>, a pressure sensor <NUM>, a flow rate sensor <NUM>, and a microphone <NUM>.

The manipulator unit <NUM> is driven together with the suction portion <NUM>, under control of the controller <NUM>. The manipulator unit <NUM> is, for example, an articulated robot arm having one or a plurality of joints.

When the suction portion <NUM> is positioned at a work position by driving of the manipulator unit <NUM>, the suction portion <NUM> holds an object by suction with negative pressure that corresponds to the driving amount of the vacuum pump <NUM>. The suction portion <NUM> is elastically deformed by negative pressure, and is brought into intimate contact with an object. In this manner, the suction portion <NUM> holds an object.

The vacuum pump <NUM> generates negative pressure that corresponds to the driving amount, and provides the generated negative pressure to the suction portion <NUM>. In this case, an example in which the suction apparatus <NUM> included in the suction system <NUM> includes the vacuum pump <NUM> is described. However, in the present embodiment, the suction apparatus <NUM> in the suction system <NUM> does not necessarily have to include the vacuum pump <NUM>, and for example, the vacuum pump <NUM> may also be provided outside the suction apparatus <NUM> and the suction system <NUM>. Also with this configuration, the controller <NUM> controls the driving amount of the vacuum pump <NUM>, so that the same effect as in the above-described example can be achieved.

The proximity sensor <NUM> measures the distance "d" to the suction portion <NUM>, and outputs, to the information obtainment unit <NUM>, information indicating the distance "d" (information indicating a degree of deformation of the suction portion <NUM>). A proximity sensor that does not directly output a distance may also be used, as long as the relationship between the measurement value output from the proximity sensor and the distance "d" is known. Examples of a detection method of the proximity sensor <NUM> include a capacitive method, an optical method, an electromagnetic induction method, and an acoustic method such as a sound wave method or an ultrasonic method. Also, examples of the capacitive sensor include a self-capacitive sensor and a mutual capacitive sensor. Alternatively, a strain sensor may also be used, instead of a proximity sensor.

The pressure sensor <NUM> measures pressure P inside the suction portion <NUM> in which negative pressure is generated using the vacuum pump <NUM>, and outputs information indicating the pressure P to the information obtainment unit <NUM>.

The flow rate sensor <NUM> is disposed with respect to, for example, the tube <NUM>, measures a flow rate of air flowing through the tube <NUM>, and outputs information indicating the flow rate to the information obtainment unit <NUM>.

The microphone <NUM> is disposed near the tube <NUM>, and measures sound generated due to the flow of air. Examples of the sound include a sound generated when an object is held by suction with the suction portion <NUM> and air flowing into the air passage from a portion between the object and the suction portion <NUM> is blocked, and a sound generated due to air flowing through the tube. The sound measured by the microphone <NUM> varies depending on the flow rate of air. The microphone <NUM> outputs information on the measured sound to the information obtainment unit <NUM>, as sound data.

The controller <NUM> includes, for example, a central processing unit (CPU), and a random access memory (RAM) or a read only memory (ROM), and performs control in response to an information process. In addition, the controller <NUM> controls the manipulator unit <NUM>. In this manner, the controller <NUM> moves the suction portion <NUM> through the manipulator unit <NUM>. Specifically, the controller <NUM> drives the manipulator unit <NUM> so that the suction portion <NUM> is positioned at a work position where the suction portion <NUM> can hold an object by suction. The controller <NUM> may also operate the manipulator unit <NUM> so that the angle of the suction portion <NUM> with respect to the object reaches a predetermined angle, after the suction portion <NUM> is positioned at the work position. In this manner, the position of the suction portion <NUM> can be finely adjusted to a more suitable position. Furthermore, the controller <NUM> controls the vacuum pump <NUM>. In this manner, the controller <NUM> drives the vacuum pump <NUM>, and causes the suction portion <NUM> to hold an object by suction. The controller <NUM> outputs, to the deterioration determination apparatus <NUM>, information on the mass of an object to be held by suction and information whether or not the suction portion <NUM> is currently holding an object by suction.

In the present embodiment, an example is described in which the controller <NUM> included in the suction system <NUM> is provided outside the suction apparatus <NUM> and the deterioration determination apparatus <NUM>. However, the present invention is not limited to the above configuration, and for example, the suction apparatus <NUM> may also include the controller <NUM>, or the deterioration determination apparatus <NUM> may also include the controller <NUM>.

The deterioration determination apparatus <NUM> includes an information obtainment unit <NUM> (a deformation information obtainment unit), a deterioration determination unit <NUM>, a storage unit <NUM>, a lifetime prediction unit <NUM>, and a notification control unit <NUM>.

The information obtainment unit <NUM> obtains, from the proximity sensor <NUM>, information indicating the distance "d". Also, the information obtainment unit <NUM> obtains, from the pressure sensor <NUM>, information indicating the pressure P. The information obtainment unit <NUM> obtains, from the flow rate sensor <NUM>, information indicating the flow rate of air flowing through the tube. The information obtainment unit <NUM> obtains sound data from the microphone <NUM>. Furthermore, the information obtainment unit <NUM> obtains, from the controller <NUM>, information on the mass of an object to be held by suction and information indicating whether or not the suction portion <NUM> is currently holding the object by suction. The information obtainment unit <NUM> outputs, to the deterioration determination unit <NUM>, the information indicating the pressure P, the information indicating the distance "d", the information indicating the flow rate of air, the sound data, the information on the mass of the object, and the information indicating whether or not the suction portion <NUM> is currently holding the object by suction.

The information obtainment unit <NUM> outputs, to the controller <NUM>, deformation data such as deformation amount, deformation speed, or deformation acceleration of the suction portion <NUM>.

The deterioration determination unit <NUM> obtains a deformation amount Δd or a spring constant k representing the degree of deterioration of the suction portion <NUM>, based on the information obtained by the information obtainment unit <NUM>. The deterioration determination unit <NUM> determines whether or not the suction portion <NUM> has deteriorated, based on the obtained deformation amount Δd or the spring constant k. The deterioration determination unit <NUM> outputs the determination result to the notification control unit <NUM>. Data processed by the deterioration determination unit <NUM> (the information indicating the pressure P, the information indicating the distance d, the deformation amount Δd, the spring constant k, the information indicating the flow rate of air, the sound data, the information on the mass of the object) is output to and stored in the storage unit <NUM>.

The deterioration determination unit <NUM> outputs, to the controller <NUM>, a signal whether or not to continue the operation. When it is determined that the suction portion <NUM> has not deteriorated, the deterioration determination unit <NUM> outputs, to the controller <NUM>, a signal for continuing the operation. In contrast, when it is determined that the suction portion <NUM> has deteriorated, the deterioration determination unit <NUM> outputs, to the controller <NUM>, a signal for stopping the operation.

The storage unit <NUM> stores the data input from the deterioration determination unit <NUM> and the measurement date and time. The storage unit <NUM> is, for example, an auxiliary storage device such as a hard disk drive or a solid state drive.

The lifetime prediction unit <NUM> obtains, from the storage unit <NUM>, time-series information indicating a change in the deformation amount Δd, the distance d, or the spring constant k in a predetermined period. The lifetime prediction unit <NUM> predicts a change in the deformation amount Δd or the spring constant k over time, based on the time-series information in the predetermined period input from the storage unit <NUM>. Examples of the approximation used for the prediction include, but are not limited to, linear approximation, polynomial approximation, power approximation, exponential approximation, and logarithmic approximation. In this manner, the lifetime prediction unit <NUM> predicts the date and time at which the deformation amount Δd or the spring constant k reaches the threshold value indicating the upper limit or the lower limit of the normal range. The lifetime prediction unit <NUM> estimates the date and time as the replacement timing of the suction portion <NUM>.

The lifetime prediction unit <NUM> outputs, to the controller <NUM>, a signal indicating whether or not to continue the operation, according to the predicted lifetime of the suction portion <NUM>. The lifetime prediction unit <NUM> may output, to the controller <NUM>, a signal for stopping the operation when the suction portion <NUM> reaches the end of its lifetime, or may also output, to the controller <NUM>, a signal for stopping the operation before a predetermined period from the end of the lifetime of the suction portion <NUM>. When the lifetime prediction unit <NUM> predicts that, for example, the end of lifetime will be reached when the suction portion <NUM> holds an object by suction <NUM> more times and stops the operation at <NUM> suctions before the end of lifetime, the lifetime prediction unit <NUM> may also output, to the controller <NUM>, a signal for stopping the operation when the suction portion <NUM> holds an object by suction another 20times.

Based on the information obtained from the deterioration determination unit <NUM> and the lifetime prediction unit <NUM>, the notification control unit <NUM> outputs, to the display unit <NUM> or the sound output unit <NUM>, the determination result of whether or not the suction portion <NUM> has deteriorated and the replacement timing of the suction portion <NUM>. When the deterioration determination unit <NUM> determines that the suction portion <NUM> has deteriorated, the notification control unit <NUM> may notify at least one of the display unit <NUM> and the sound output unit <NUM> that the suction portion <NUM> has deteriorated. The notification control unit <NUM> may cause, for example, in order to notify deterioration of the suction portion <NUM>, the display unit <NUM> to emit light of a predetermined color or display an image for notifying deterioration of the suction portion <NUM>, or may also cause the sound output unit <NUM> to output a predetermined sound for notifying deterioration of the suction portion <NUM>.

The notification control unit <NUM> may also notify at least one of the display unit <NUM> and the sound output unit <NUM> that the lifetime of the suction portion <NUM> predicted by the lifetime prediction unit <NUM> is close to its end. The notification control unit <NUM> may also notify, for example, at least one of the display unit <NUM> and the sound output unit <NUM> that the suction portion <NUM> will reach the end of its lifetime after a predetermined period has elapsed, at a point in time before the predetermined period. Specifically, for example, the notification control unit <NUM> may also cause the display unit <NUM> to emit light of a predetermined color or display an image, for notifying that the suction portion <NUM> will reach the end of its lifetime after a predetermined period has elapsed. Alternatively, the notification control unit <NUM> may also cause the sound output unit <NUM> to output a predetermined sound, for notifying that the suction portion <NUM> will reach the end of its lifetime after a predetermined period has elapsed. The predetermined period is not limited to a specific period, but is, for example, one month.

The display unit <NUM> displays light or an image, in accordance with an instruction transmitted from the notification control unit <NUM>. The display unit <NUM> is not limited to a specific device as long as it emits light or displays an image, and examples of the display unit <NUM> include a lamp or a display.

The sound output unit <NUM> outputs sound, in accordance with an instruction transmitted from the notification control unit <NUM>. Examples of the sound include a buzzer sound, for example. The sound output unit <NUM> is not limited to a specific device as long as it outputs sound, and examples of the sound output unit <NUM> include a speaker.

Various operation examples of the deterioration determination apparatus <NUM> will be described below. Hereinafter, an operation of detecting deterioration of the suction portion <NUM> performed by the deterioration determination apparatus <NUM> according to an embodiment will be described with reference to <FIG>.

<FIG> is a flow chart showing how the deterioration determination apparatus <NUM> operates. First, with reference to <FIG>, an operation example in which the deterioration determination apparatus <NUM> obtains information on deformation and performs deterioration determination and lifetime prediction will be described.

First, a signal indicating that the suction portion <NUM> has held and lifted by suction a predetermined object W is input from the controller <NUM> to the information obtainment unit <NUM> (step S1).

Next, the information obtainment unit <NUM> obtains, from the proximity sensor <NUM>, information on deformation occurring in the suction portion <NUM> (for example, information indicating the distance d) (step S2).

Then, the information obtained by the information obtainment unit <NUM> is input to the deterioration determination unit <NUM>. The deterioration determination unit <NUM> obtains the deformation amount Δd of the suction portion <NUM>, based on the distance d obtained in a state where the suction portion <NUM> is holding the object W by suction. Alternatively, the deterioration determination unit <NUM> may also obtain, based on a measurement value indicating deformation occurring in the suction portion <NUM>, the deformation amount Δd that corresponds to the measurement value, using a table stored in advance. The deterioration determination unit <NUM> determines whether or not the deformation amount Δd is within a normal range (step S3).

When the deterioration determination unit <NUM> determines that the deformation amount Δd is within the normal range (YES in step S3), the deterioration determination unit <NUM> stores the data in the storage unit <NUM> (step S4), and determines that the suction portion <NUM> has not deteriorated (step S5).

After the deterioration determination unit <NUM> determines that the suction portion <NUM> has not deteriorated in step S5, the lifetime prediction unit <NUM> obtains the time-series information from the storage unit <NUM> (step S6).

Based on the time-series information, the lifetime prediction unit <NUM> estimates the timing to replace the suction portion <NUM> (step S7).

<FIG> shows an example of a temporal change in the deformation amount Δd of the suction portion <NUM>. The vertical axis represents the deformation amount Δd, and the horizontal axis represents time. When the rubber contained in the suction portion <NUM> deteriorates over time, the rubber becomes hard. For this reason, the deformation amount Δd of the suction portion <NUM> measured when the suction portion <NUM> holds an object by suction decreases with time. The lifetime prediction unit <NUM> obtains a curve indicating the predicted change of the deformation amount Δd, using the deformation amount Δd over a predetermined period up to time point ti. The lifetime prediction unit <NUM> can predict the replacement timing te from the intersection of the obtained curve and the threshold value that indicates the limit of the normal range. The lifetime prediction unit <NUM> outputs, to the notification control unit <NUM>, the timing te for replacing the suction portion <NUM>.

The notification control unit <NUM> displays the replacement timing te on the display unit <NUM>. The notification control unit <NUM> causes the sound output unit <NUM> to output the replacement timing te as sound (step S8). After step S8, the deterioration determination apparatus <NUM> ends the process.

In contrast, when the deterioration determination unit <NUM> determines that the deformation amount Δd is not within the normal range (NO in step S3), the deterioration determination unit <NUM> stores the data in the storage unit <NUM> (step S9), and determines that the suction portion <NUM> has deteriorated (step S10). The deterioration determination unit <NUM> outputs the determination result to the notification control unit <NUM>.

After the deterioration determination unit <NUM> determines that the suction portion <NUM> has deteriorated in step S10, the notification control unit <NUM> causes the display unit <NUM> to display that the suction portion <NUM> has deteriorated. The notification control unit <NUM> causes the sound output unit <NUM> to output a sound indicating that the suction portion <NUM> has deteriorated (step S11). After step S11, the deterioration determination apparatus <NUM> ends the process.

In this manner, the notification control unit <NUM> notifies the user of the determination result of whether or not the suction portion <NUM> has deteriorated or the replacement timing te of the suction portion <NUM>. According to the above-described operation example, it is possible to appropriately determine whether or not the suction portion <NUM> has deteriorated, which is difficult to distinguish from the appearance of the suction portion <NUM>. In addition, it is possible to replace the suction portion <NUM> at an appropriate timing by predicting the lifetime of the suction portion <NUM>. Furthermore, because the maintenance schedule can be determined before an abnormality occurs in the suction portion <NUM>, it is possible to avoid an unexpected stop of the production line.

In the above-described operation example <NUM>, the case where the suction portion <NUM> holds a predetermined object by suction has been described. However, it may also be determined whether or not the suction portion <NUM> has deteriorated when the suction portion <NUM> holds any object flowing in the production line by suction. Alternatively, it may also be determined whether or not the suction portion <NUM> has deteriorated when the suction portion <NUM> holds the object by suction with an optionally-set negative pressure. The information obtainment unit <NUM> obtains, from the controller <NUM>, information on the mass of the object that has been held by suction with the suction portion <NUM>. The information obtainment unit <NUM> obtains, from the pressure sensor <NUM>, information on pressure. The storage unit <NUM> stores in advance a normal range of the deformation amount Δd for the obtained mass and/or the pressure. The deterioration determination unit <NUM> obtains, from the storage unit <NUM>, a normal range of the deformation amount Δd that corresponds to the mass and/or pressure of the object that has been held by suction with the suction portion <NUM>, and determines whether or not the suction portion <NUM> has deteriorated.

<FIG> is a flowchart showing the operation of the deterioration determination apparatus <NUM>. Next, with reference to <FIG>, an operation example will be described for a case where the deterioration determination apparatus <NUM> specifies the spring constant of the suction portion <NUM> and determines whether or not the suction portion <NUM> has deteriorated according to the spring constant. For convenience of description, steps having the same functions as those described in the above embodiment are denoted by the same reference numerals, and their description will not be repeated.

Steps S1 and S2 are the same as those in the operation example <NUM>.

The deterioration determination unit <NUM> obtains the deformation amount Δd of the suction portion <NUM>, based on the distance d in a state where the suction portion <NUM> holds the object W by suction. The deterioration determination unit <NUM> specifies the spring constant k, based on the deformation amount Δd, the value of the pressure P, the mass M and the suction area S of the object W (step S20). When the suction portion <NUM> holds a predetermined object W by suction, the mass M of the object W is known. In addition, the pressure P and the suction area S are also known.

The deterioration determination unit <NUM> determines whether or not the spring constant k is within a normal range (step S21). When the spring constant k is within the normal range (Yes in step S21), the process proceeds to step S4. In contrast, when the spring constant k is not within the normal range (No in step S21), the process proceeds to step S9. Steps S4 to S11 are the same as those in the operation example <NUM>, but the step <NUM> will be supplementarily described.

<FIG> shows an example of a temporal change in the spring constant k of the suction portion <NUM>. The vertical axis represents the spring constant k, and the horizontal axis represents time. When the rubber contained in the suction portion <NUM> deteriorates over time, the rubber becomes hard. For this reason, the spring constant k of the suction portion <NUM> increases with time when the suction portion <NUM> holds an object by suction. The lifetime prediction unit <NUM> obtains a curve indicating the predicted change of the spring constant k, using the spring constants k over the predetermined period up to the time point ti. The lifetime prediction unit <NUM> can predict the replacement timing te from the intersection of the obtained curve and the threshold value that indicates the limit of the normal range.

In the above-described operation example <NUM>, the case where the suction portion <NUM> holds a predetermined object by suction has been described. However, it may also be determined whether or not the suction portion <NUM> has deteriorated when the suction portion <NUM> holds any object flowing in the production line by suction. Alternatively, it may also be determined whether or not the suction portion <NUM> has deteriorated when the suction portion <NUM> holds the object by suction with an optionally-set negative pressure. The information obtainment unit <NUM> obtains, from the controller <NUM>, information on the mass of an object that has been held by suction with the suction portion <NUM>. The information obtainment unit <NUM> obtains, from the pressure sensor <NUM>, information on pressure. The deterioration determination unit <NUM> obtains the spring constant k of the suction portion <NUM>, using the mass of the object that has been held by suction with the suction portion <NUM>, the pressure, and the deformation amount Δd of the suction portion <NUM>. Operation example <NUM>.

<FIG> is a flowchart showing the operation of the deterioration determination apparatus <NUM> according to an embodiment of the present invention. Next, with reference to <FIG>, an operation example in which the deterioration determination apparatus <NUM> causes the suction portion <NUM> to sequentially hold a plurality of objects W having different masses by suction, obtains information on deformation of the suction portion <NUM> in each case, and determines whether or not the suction portion has deteriorated. For convenience of description, steps having the same functions as those described in the above embodiment are denoted by the same reference numerals, and their description will not be repeated.

First, a signal indicating that the suction portion <NUM> has held and lifted an object <NUM> by suction is input from the controller <NUM> to the information obtainment unit <NUM> (step S30). At this time, information on the mass of the object <NUM> is also input from the controller <NUM> to the information obtainment unit <NUM>.

Next, the information obtainment unit <NUM> obtains, from the proximity sensor <NUM>, information on deformation of the suction portion <NUM> holding the object <NUM> by suction (for example, information indicting the distance d1) (step S31).

Next, a signal indicating that the suction portion <NUM> has held and lifted an object <NUM> by suction is input from the controller <NUM> to the information obtainment unit <NUM> (step S32). At this time, information on the mass of the object <NUM> is also input from the controller <NUM> to the information obtainment unit <NUM>. Here, the object <NUM> and the object <NUM> have different masses. Accordingly, the object <NUM> and the object <NUM> have different normal ranges regarding the deformation of the suction portion <NUM>.

Next, the information obtainment unit <NUM> obtains, from the proximity sensor <NUM>, information on deformation of the suction portion <NUM> when the suction portion <NUM> holds the object <NUM> by suction (for example, information indicating a distance d2) (step S33).

Next, the information that is obtained when the suction portion <NUM> sequentially holds the object <NUM> and the object <NUM> by suction and that is obtained by the information obtainment unit <NUM> is input to the deterioration determination unit <NUM>. The deterioration determination unit <NUM> obtains the deformation amount Δd1 of the suction portion <NUM>, based on the distance d1 in a state where the suction portion <NUM> holds the object <NUM> by suction. In addition, the deterioration determination unit <NUM> obtains the deformation amount Δd2 of the suction portion <NUM>, based on the distance d2 in a state where the suction portion <NUM> holds the object <NUM> by suction. The deterioration determination unit <NUM> determines whether or not the deformation amount Δd1 and the deformation amount Δd2 are within the respective normal ranges (step S34). When the deformation amount Δd1 is within its normal range and the deformation amount Δd2 is also within its normal range, the process proceeds to step S4. In contrast, when the deformation amount Δd1 is not within its normal range or the deformation amount Δd2 is not within its normal range, the process proceeds to step S9.

Steps S4 to S11 are the same as those in the operation example <NUM>.

In the operation example <NUM> described above, the deterioration determination method is limited to a case where two types of objects are used, but three or more types of objects may be used in practice.

Although the determination method using the deformation amount Δd is described in the operation example <NUM>, the determination method using the spring constant k may also be applied to a case in which a plurality of objects are used as in the operation example <NUM>. Ideally, the spring constant k is considered to be constant, regardless of the mass of the object. In this case, the deterioration determination unit <NUM> specifies spring constants k1 to kn of a plurality of objects <NUM> to n (n is an integer of <NUM> or more), and calculates an average value k of the spring constants k1 to kn. Then, the deterioration determination unit <NUM> determines whether or not the average value k is within a normal range of the spring constant. The deterioration determination unit <NUM> may also obtain a representative value other than the average value (for example, a minimum approximation, a minimum, a maximum, or an intermediate value) from the plurality of spring constants k1 to kn, and determine whether or not the representative value is within a normal range.

<FIG> is a flowchart showing the operation of the deterioration determination apparatus <NUM> according to still another embodiment of the present invention. Next, with reference to <FIG>, an operation example will be described in which the deterioration determination apparatus <NUM> causes the suction portion <NUM> to sequentially hold an object by suction with a plurality of negative pressures, obtains information on deformation of the suction portion <NUM> in each case, and determines whether or not the suction portion <NUM> has deteriorated. For convenience of description, steps having the same functions as those described in the above embodiment are denoted by the same reference numerals, and their description will not be repeated.

First, a signal indicating that the suction portion <NUM> has held and lifted an object by suction with a first negative pressure is input from the controller <NUM> to the information obtainment unit <NUM> (step S40).

Next, the information obtainment unit <NUM> obtains, from the proximity sensor <NUM>, information on deformation of the suction portion <NUM> in a state of holding the object by suction with the first negative pressure (for example, information indicating a distance d1) (step S41). In addition, the information obtainment unit <NUM> obtains, from the pressure sensor <NUM>, information indicating the first negative pressure P1.

Next, a signal indicating that the suction portion <NUM> has held and lifted the object by suction with a second negative pressure is input from the controller <NUM> to the information obtainment unit <NUM> (step S42). The first negative pressure and the second negative pressure are different from each other. Accordingly, the first negative pressure and the second negative pressure have different normal ranges related to deformation.

Next, the information obtainment unit <NUM> obtains, from the proximity sensor <NUM>, information on deformation of the suction portion <NUM> in a state of holding the object by suction with the second negative pressure (for example, information indicating a distance d2) (step S43). In addition, the information obtainment unit <NUM> obtains, from the pressure sensor <NUM>, information indicating the second negative pressure P2.

Next, the information that is obtained when the object is sequentially held by suction with the first negative pressure P1 and the second negative pressure P2 and that is obtained by the information obtainment unit <NUM> is input to the deterioration determination unit <NUM>. The deterioration determination unit <NUM> obtains the deformation amount Δd1 of the suction portion <NUM>, based on the distance d1 in a state where the suction portion <NUM> holds the object by suction with the first negative pressure P1. In addition, the deterioration determination unit <NUM> obtains the deformation amount Δd2 of the suction portion <NUM>, based on the distance d2 in a state where the suction portion <NUM> holds the object by suction with the second negative pressure P2. The deterioration determination unit <NUM> determines whether or not the deformation amount Δd1 and the deformation amount Δd2 are within the respective normal ranges (step S44). When the deformation amount Δd1 is within its normal range and the deformation amount Δd2 is also within its normal range, the process proceeds to step S4. In contrast, when the deformation amount Δd1 is not within its normal range or the deformation amount Δd2 is not within its normal range, the process proceeds to step S9.

In the operation example <NUM> described above, the deterioration determination method is limited to a case where two types of negative pressures are used, but three or more types of negative pressures may be used in practice.

Although the determination method using the deformation amount Δd is described in the operation example <NUM>, the determination method using the spring constant k may also be applied to a case in which a plurality of negative pressures are used as in the operation example <NUM>. Ideally, the spring constant k is considered to be constant, regardless of negative pressure. In this case, the deterioration determination unit <NUM> specifies spring constants k1 to kn for the plurality of first to n-th negative pressures, and calculates an average value k of the spring constants k1 to kn. Then, the deterioration determination unit <NUM> determines whether or not the average value k is within a normal range of the spring constant. The deterioration determination unit <NUM> may also obtain a representative value other than the average value (for example, a minimum approximation, a minimum, a maximum, or an intermediate value) from the plurality of spring constants k1 to kn, and determine whether or not the representative value is within a normal range.

Operation examples <NUM> to <NUM> described above can be implemented in combination. The spring constant may also be specified, for example, by holding a plurality of objects having different masses by suction with a plurality of negative pressures that are different from each other.

The deterioration determination unit <NUM> may also determine whether or not the suction portion <NUM> has deteriorated, that is to say, whether or not the suction portion <NUM> is in an abnormal condition, depending on whether or not the pressure (the first negative pressure P1 or the second negative pressure P2) is within a normal range that is related to a pressure and set for the suction portion <NUM>.

When the pressure is within the normal range, the deterioration determination unit <NUM> determines that the suction portion <NUM> has not deteriorated. In contrast, when the pressure is outside the normal range, the deterioration determination unit <NUM> determines that the suction portion <NUM> has deteriorated. When there is a crack in the suction portion <NUM>, for example, air flows into the suction portion <NUM>, and thus the decrease in pressure is reduced. Similarly, when the suction portion <NUM> is deformed due to deterioration, the suction portion <NUM> does not come into intimate contact with an object, and air may flow into the suction portion <NUM>. Also, when dust or the like is sandwiched between the suction portion <NUM> and an object, the suction portion <NUM> does not come into intimate contact with the object, and air may flow into the suction portion <NUM>.

Also, the information obtainment unit <NUM> may also obtain, from the flow rate sensor <NUM> or the microphone <NUM>, information indicating the flow rate of air flowing through the tube, or sound data. When the information obtainment unit <NUM> obtains the flow rate of air instead of pressure, the deterioration determination unit <NUM> may also determine whether or not the suction portion <NUM> has deteriorated, that is to say, whether or not the suction portion <NUM> is in an abnormal condition, according to the flow rate. Similarly, when the information obtainment unit <NUM> obtains sound instead of pressure, the deterioration determination unit <NUM> may also determine whether or not the suction portion <NUM> has deteriorated, that is to say, whether or not the suction portion <NUM> is in an abnormal condition, according to the sound. When air flows into the suction portion <NUM>, for example, the flow rate of air or the sound increases due to the flow of air.

In order to determine whether or not the suction portion <NUM> has deteriorated, the suction system <NUM> may include any one of the pressure sensor <NUM>, the flow rate sensor <NUM>, and the microphone <NUM> (the other two devices may also be omitted).

Control blocks (in particular, the information obtainment unit <NUM>, the deterioration determination unit <NUM>, the lifetime prediction unit <NUM>, and the notification control unit <NUM>) included in the deterioration determination apparatus <NUM> may be implemented by a logic circuit (hardware) formed in an integrated circuit (IC chip) or the like, or may also be implemented by software.

In the latter case, the deterioration determination apparatus <NUM> includes a computer that executes instructions of a program, which is software for implementing the functions. The computer includes, for example, one or more processors, and a computer-readable recording medium storing the program. In the computer, the processor reads the program from the recording medium and executes the program, thereby achieving the object of the present invention. As the processor, for example, a central processing unit (CPU) can be used. As the recording medium, a "non-transitory tangible medium" such as a read only memory (ROM), a tape, a disk, a card, a semiconductor memory, or a programmable logic circuit can be used. In addition, the deterioration determination apparatus <NUM> may further include, for example, a random access memory (RAM) that develops the program. The program may be supplied to the computer through any transmission medium (for example, a communication network, or a broadcast wave) capable of transmitting the program. One aspect of the present invention can also be achieved in the form of a data signal embedded in a carrier wave in which the program is embodied by electronic transmission.

Claim 1:
A deterioration determination apparatus (<NUM>), comprising:
a deformation information obtainment unit (<NUM>) configured to obtain information on deformations of a suction portion (<NUM>) occurring when the suction portion (<NUM>) sequentially holds a plurality of objects having different masses by suction, which suction portion (<NUM>) is configured to hold an object by suction with negative pressure and elastically deforms by the negative pressure; and
a deterioration determination unit (<NUM>) configured to determine whether or not the suction portion (<NUM>) has deteriorated, depending on whether or not the deformations of the suction portion (<NUM>) occurring when the suction portion (<NUM>) sequentially holds the plurality of objects by suction are within normal ranges set for the respective objects.