Patent Description:
An automatic winder (a yarn winding machine) of <CIT> includes winding units (yarn processing units) and a doffing device (a work cart). The winding units are arranged side by side in one direction. The doffing device can travel in a direction in which the winding units are arranged, and performs doffing on the winding units.

The automatic winder of <CIT> includes an index block for alignment of the doffing device and the winding unit. The index block is provided on a rail on which the doffing device travels.

The index block is provided at a position corresponding to each winding unit. The doffing device is provided with an index plate engageable with the index block. In a state where the index plate is engaged with the index block, the doffing device is located at an appropriate position for performing doffing on the winding unit.

In the configuration of <CIT>, positioning accuracy may deteriorate due to wear of the index plate or the index block. Further, in order to change a stop position of the doffing device, it is necessary to change a position or a shape of the index plate or the index block. Note that, in the yarn winding machine, a work cart (for example, a yarn joining device) other than the doffing device may be provided. Further, the position at which the work cart is stopped is not limited to the yarn processing unit. <CIT> discloses a yarn winding machine of according to the preamble claim <NUM>. Such a yarn winding machine is also disclosed in <CIT>, <CIT>, <CIT> and <CIT>.

The present invention has been made in view of the above circumstances. A main object is avoiding to deteriorate accuracy of a position at which a work cart is stopped. Furthermore, an object of the present invention is to provide a yarn winding machine capable of adjusting a position at which the work cart is stopped.

The problems to be solved by the present invention are as described above, and now, the means and effects for solving such problems will be described.

According to the present invention, a yarn winding machine having the features according to claim <NUM> is provided. The yarn winding machine includes a plurality of yarn processing units, a work cart, a stop position identifier, an optical sensor, and a control section. The yarn processing unit winds a yarn around a bobbin to form a package. The work cart travels in a direction in which the yarn processing units are arranged as a travelling direction, and performs work on the yarn processing unit. The stop position identifier is provided at a position corresponding to a stop position of the work cart. The optical sensor is provided on the work cart and detects the stop position identifier. The control section calculates a position of the work cart with respect to the stop position identifier, and performs control to stop the work cart at a stop position of the work cart determined in advance, on the basis of magnitude of a detection value or on the basis of a light receiving position that is a position where the stop position identifier is detected in an area detectable by the optical sensor, the magnitude of the detection value or the light receiving position being detected by the optical sensor detecting a target step position identifier to stop the work cart.

This enables calculation of a position of the work cart in a non-contact manner, and thus the accuracy of the position at which the work cart is stopped is unlikely to deteriorate. In addition, since the position of the work cart is calculated using the detection value or the light receiving position detected by the optical sensor, the position at which the work cart is stopped can be adjusted by changing the detection value or the light receiving position for stopping the work cart.

The stop position is set for each yarn processing unit, and the work cart may perform work on the yarn processing unit after stopping at the stop position.

This allows the work cart to perform the work with an appropriate positional relationship with respect to the yarn processing unit.

This makes it possible to acquire more information than a spot-shaped optical sensor.

A direction of detection by the line sensor is a direction orthogonal to a surface provided with the stop position identifier and orthogonal to the travelling direction.

As a result, by performing detection by the optical sensor while travelling, a detection range becomes a planar and wide range.

On the surface provided with the stop position identifier, in a direction orthogonal to the travelling direction, the stop position identifier has a longer length on one side than another side in the travelling direction.

This allows calculation of a positional relationship between the optical sensor and the stop position identifier in the travelling direction.

On the surface provided with the stop position identifier, the stop position identifier has a constant increasing ratio of the length in the direction orthogonal to the travelling direction.

As a result, a distance in the travelling direction between the optical sensor and the stop position identifier is proportional to a detection value of the optical sensor, which enables calculation of a specific distance between the optical sensor and the stop position identifier.

The control section may store a plurality of stop positions with respect to the stop position identifier, and store one of the plurality of stop positions in association with each work content of the work cart, and the control section may determine the stop position of the work cart with respect to the stop position identifier on the basis of the work content.

This enables to stop the work cart at an appropriate position according to the work content, by using one stop position identifier.

The stop position identifier may include a first stop position identifier as a target to stop the work cart and a second stop position identifier selected from the stop position identifiers between the work cart and the first stop position identifier in the travelling direction, and the control section may decelerate the work cart on the basis of detection of the second stop position identifier by the optical sensor.

As a result, the work cart travels at a high speed while being far from the stop position, and travels at a low speed while being close to the stop position, so that the work cart can reach the stop position in a short time.

There may be provided a yarn processing unit identifier that is for identifying the yarn processing unit and is provided at a position different from the stop position identifier in a direction orthogonal to the travelling direction, and a part of the stop position identifier may overlap with the yarn processing unit identifier in the travelling direction.

This enables to identify the yarn processing unit while aligning the stop position, by using the optical sensor for detection of the stop position. That is, it can be confirmed that the target yarn processing unit is reached.

The optical sensor may read the yarn processing unit identifier in a way different from the stop position identifier.

This enables clear distinction between the stop position identifier and the yarn processing unit identifier.

The yarn processing unit identifier may be provided in the yarn processing unit.

The work cart may travel along a rail, and the stop position identifier may be an opening formed in the rail.

This enables creation of the stop position identifier with simple work.

The stop position identifier may be provided in the yarn processing unit.

This can omit or simplify a process of registering the stop position for each yarn processing unit when performing work on the yarn processing unit.

There may be included an auxiliary identifier that is provided between the yarn processing units in the travelling direction and is for identifying a position of the work cart in the travelling direction.

This enables more detailed calculation of the position of the work cart.

A following non-claimed teaching method is provided. A yarn winding machine that performs a teaching method includes: a plurality of yarn processing units adapted to wind a yarn around a bobbin to form a package; and a work cart adapted to travel in a direction in which the yarn processing units are arranged as a travelling direction, to perform work on the yarn processing units. The teaching method is adapted to teach a stop position of the work cart to the yarn winding machine. The teaching method includes an attaching step and a storing step. In the attaching step, a positioning member is attached to the yarn processing unit. In the storing step, magnitude of a detection value or a light receiving position that is a position where a stop position identifier is detected in an area detectable by the optical sensor is stored, the magnitude of the detection value or the light receiving position being detected by the optical sensor detecting a stop position identifier provided at a position corresponding to a stop position of the work cart in a state where the positioning member is in contact with the work cart.

This enables registration of the stop position for each yarn processing unit.

The teaching method may include a preparing step of attaching a positioning sensor to the work cart, and the yarn processing units may include a first yarn processing unit and a second yarn processing unit. The storing step may include: a first storing step of storing a detection value or a light receiving position for the first yarn processing unit; and a second storing step that is performed after the first storing step and is of storing a detection value or a light receiving position for the second yarn processing unit. In the first storing step, in a state where the positioning member attached to the first yarn processing unit is in contact with the work cart, the optical sensor may detect a detection value or a light receiving position, and the positioning sensor may detect the first yarn processing unit. In the second storing step, in a state where the second yarn processing unit and the work cart are aligned in a non-contact manner, a stop position of the work cart with respect to the second yarn processing unit may be calculated and stored on the basis of the detection value or the light receiving position detected by the optical sensor and on the basis of the position of the second yarn processing unit detected by the positioning sensor.

This enables registration of the stop position for the second and subsequent yarn processing units without arranging the positioning member in the second and subsequent yarn processing units.

Next, an embodiment of the present invention will be described with reference to the drawings. With reference to <FIG>, an overall configuration of an automatic winder (a yarn winding machine) will be described.

An automatic winder <NUM> includes a plurality of yarn processing units <NUM> arranged in parallel, a doffing cart (a work cart) <NUM>, and a machine control device <NUM>.

Each of the yarn processing units <NUM> includes a yarn supplying section <NUM>, a yarn unwinding assisting device <NUM>, a tension applying device <NUM>, a yarn joining device <NUM>, a yarn quality measuring instrument <NUM>, a cradle <NUM>, a winding drum <NUM>, and a housing <NUM>. The yarn supplying section <NUM> supports a yarn supplying bobbin <NUM>. The yarn unwinding assisting device <NUM> comes into contact with a portion (a balloon) bulged outward in a yarn unwound from the yarn supplying bobbin <NUM> when being swung around by a centrifugal force. This enables to suppress the yarn from being excessively swung, and to unwind the yarn with a constant tension. The tension applying device <NUM> applies a predetermined tension on a travelling yarn. The yarn unwound from the yarn supplying bobbin <NUM> and a yarn of a package <NUM> are individually guided to the yarn joining device <NUM>. The yarn joining device <NUM> joins the guided yarns with each other. The yarn quality measuring instrument <NUM> measures the quality of the travelling yarn (for example, a yarn thickness, a change amount, or the like) with an optical sensor or the like. To the cradle <NUM>, a winding bobbin is attached. The package <NUM> is formed by winding the yarn around the winding bobbin. The winding drum <NUM> comes into contact with the package <NUM> and rotates, to wind the yarn around the winding bobbin while traversing the yarn. Inside the housing <NUM>, an electric component such as a unit control section <NUM> described later is provided.

The doffing cart <NUM> can travel along a parallel direction of the yarn processing units <NUM>. Specifically, a rail <NUM> is formed along the parallel direction above the yarn processing unit <NUM>, and the doffing cart <NUM> travels along the rail <NUM>. When the package is fully wound in a certain yarn processing unit <NUM>, the doffing cart <NUM> travels to the yarn processing unit <NUM> and stops. The doffing cart <NUM> removes the fully-wound package of the yarn processing unit <NUM>. Then, a new winding bobbin around which a yarn is not wound is supplied to the yarn processing unit <NUM>.

Specifically, the doffing cart <NUM> includes a yarn pull-out arm <NUM>, a cradle opening arm <NUM>, and a chucker <NUM>. The yarn pull-out arm <NUM> is expanded and contracted by an actuator such as an air cylinder (not illustrated). To a distal end of the yarn pull-out arm <NUM>, a suction-type yarn catching section is attached, and pulls out a yarn from the yarn supplying bobbin <NUM>. The cradle opening arm <NUM> operates and opens the cradle <NUM> to remove the fully-wound package <NUM> from the cradle <NUM>. The chucker <NUM> grips an empty winding bobbin held in a bobbin stocker (not illustrated) and supplies the empty winding bobbin to the cradle <NUM>.

Next, a control system of the automatic winder <NUM> will be described with reference to <FIG>.

As described above, the yarn processing unit <NUM> includes the unit control section <NUM>. The unit control section <NUM> controls each section of the yarn processing unit <NUM>.

The doffing cart <NUM> includes a cart control section (a control section) <NUM>, a travelling motor <NUM>, and an optical sensor <NUM>. The cart control section <NUM> controls each section of the doffing cart <NUM>. The travelling motor <NUM> is used to cause the doffing cart <NUM> to travel along the rail <NUM>. The optical sensor <NUM> is used to stop the doffing cart <NUM> at a target position. The cart control section <NUM> calculates a position of the doffing cart <NUM> on the basis of a detection result of the optical sensor <NUM>, and controls the travelling motor <NUM>. Then, the doffing cart <NUM> is caused to travel to an appropriate position to perform doffing on the yarn processing unit <NUM>.

The machine control device <NUM> includes a machine control section <NUM>, an input section <NUM>, and a display section <NUM>. The machine control section <NUM> controls the plurality of yarn processing units <NUM> provided in the automatic winder <NUM>. In addition, the machine control section <NUM> performs processing according to a command made by an operator operating the input section <NUM>. For example, when the operator operates the input section <NUM> to set a condition relating to winding of a yarn, the setting is reflected in all the yarn processing units <NUM>. Further, when the operator operates the input section <NUM> to issue a command to display information relating to an operation status and/or yarn quality of each yarn processing unit <NUM>, the machine control section <NUM> displays the information on the display section <NUM>. Further, the machine control device <NUM> can communicate with each yarn processing unit <NUM> and the doffing cart <NUM>.

Each of the unit control section <NUM>, the cart control section <NUM>, and the machine control section <NUM> includes an arithmetic device such as a CPU, and a storage device such as an HDD, an SSD, or a flash memory. Various programs are stored in the storage device, and the arithmetic device reads and executes the programs to perform the above-described control.

With reference to <FIG>, control of causing the doffing cart <NUM> to travel to the target stop position will be described. In the following description, an appropriate position of the doffing cart <NUM> to perform doffing on the yarn processing unit <NUM> is referred to as a stop position. A stop position with respect to the yarn processing unit <NUM> to perform doffing next is particularly referred to as a target stop position.

First, the optical sensor <NUM> and a stop position identifier <NUM> used to detect a position of the doffing cart <NUM> will be described. The optical sensor <NUM> is a reflective line sensor. The optical sensor <NUM> irradiates an irradiation surface with linear light, receives reflected light on a light receiving surface, and outputs a received light amount as a detection value. The optical sensor <NUM> of the present embodiment does not need to be able to detect a position of the reflected light incident on the light receiving surface.

The optical sensor <NUM> is provided on the doffing cart <NUM> and travels integrally with the doffing cart <NUM>. The optical sensor <NUM> of the present embodiment is provided on an upper surface of the doffing cart <NUM>, but may be provided at different positions. In addition, a longitudinal direction of linear light applied to the irradiation surface by the line sensor is hereinafter referred to as a "detection direction". Further, an area where the optical sensor <NUM> transmits and receives light and performs detection is referred to as a detection area 47a (see <FIG>). In the present embodiment, the detection direction of the optical sensor <NUM> is parallel to a height direction (a vertical direction) of the automatic winder <NUM>. In other words, the detection direction of the optical sensor <NUM> is a direction orthogonal to the travelling direction and orthogonal to a horizontal plane. The optical sensor <NUM> irradiates a side surface of the rail <NUM> with light and detects reflected light.

The rail <NUM> is provided with a plurality of stop position identifiers <NUM>. As illustrated in <FIG>, the stop position identifier <NUM> is provided corresponding to each yarn processing unit <NUM>. The stop position identifier <NUM> has a light reflectance different from that of an installation surface (for example, a side surface of the rail <NUM>) provided with the stop position identifier <NUM>. The stop position identifier <NUM> may be, for example, a member (for example, a black member) having a light reflectance lower than that of the installation surface or a member (a member that performs specular reflection) having a light reflectance higher than that of the installation surface. Alternatively, the stop position identifier <NUM> may be formed by cutting out the installation surface to form an opening. In this case, the stop position identifier <NUM> can be detected by detecting surroundings of the stop position identifier <NUM>. Further, the detection direction of the optical sensor <NUM> can also be rephrased as a direction orthogonal to the travelling direction on the installation surface of the stop position identifier <NUM>.

As illustrated in <FIG>, the stop position identifier <NUM> includes a first parallel part <NUM>, an inclined part <NUM>, and a second parallel part <NUM>. The first parallel part <NUM> and the second parallel part <NUM> are portions whose lengths (widths) in the detection direction are constant in the travelling direction. A length of the inclined part <NUM> in the detection direction changes depending on a position in the travelling direction. That is, the length in the detection direction increases from one side toward another side in the travelling direction. In particular, in the present embodiment, since the inclined part <NUM> is a straight line, an increasing ratio (a changing ratio) of the length in the detection direction is constant. In a situation where the detection area 47a overlaps with the inclined part <NUM>, a received light amount (a detection value) changes as the doffing cart <NUM> moves in the travelling direction. By using this, a positional relationship between the stop position identifier <NUM> and the optical sensor <NUM> (that is, the doffing cart <NUM>) can be detected. A received light amount (hereinafter, referred to as a reference received light amount) of the optical sensor <NUM> in a state where the doffing cart <NUM> is arranged at the stop position with respect to the yarn processing unit <NUM> is stored in advance. Then, during work of the automatic winder <NUM>, the doffing cart <NUM> is caused to travel such that the received light amount detected by the optical sensor <NUM> coincides with the reference received light amount. This allows the doffing cart <NUM> to be accurately stopped at the target stop position. Note that the first parallel part <NUM> and/or the second parallel part <NUM> may be omitted.

Hereinafter, with reference to <FIG> and <FIG>, a flow of stopping the doffing cart <NUM> at the target stop position will be described. First, when doffing is required in the yarn processing unit <NUM>, the unit control section <NUM> transmits the fact that the doffing is required, to the machine control section <NUM>. The machine control section <NUM> transmits information specifying the yarn processing unit <NUM> that requires the doffing, to the cart control section <NUM>.

When receiving information regarding the target yarn processing unit <NUM> from the machine control section <NUM> (S101), the cart control section <NUM> starts high-speed travelling toward the stop position identifier <NUM> (a first stop position identifier) corresponding to the target yarn processing unit <NUM> (S102, high-speed travelling in <FIG>).

Next, the cart control section <NUM> determines whether or not the stop position identifier <NUM> immediately before the target is detected (S103). Specifically, the process is performed as follows. Since the cart control section <NUM> stores information on a yarn processing unit <NUM> (specifically, identification information for identification of the yarn processing unit <NUM>) that has performed doffing last time, the doffing cart <NUM> can specify the yarn processing unit <NUM> currently in proximity. Therefore, the number of the yarn processing units <NUM> to pass by to reach the target yarn processing unit <NUM> can be calculated. In addition, the cart control section <NUM> can detect the stop position identifier <NUM> by using the optical sensor <NUM> even during the high-speed travelling. As a result, when the number of the yarn processing units <NUM> to pass by before reaching the target yarn processing unit <NUM> is N, and the number of the yarn processing units <NUM> that have been passed by at the current time is M, the cart control section <NUM> can determine whether or not N - M has become <NUM>. When N - M becomes <NUM>, the doffing cart <NUM> reaches the stop position identifier <NUM> (a second stop position identifier) immediately before the target.

When it is determined that the stop position identifier <NUM> immediately before the target is detected, the cart control section <NUM> shifts to low-speed travelling (S104, low-speed travelling in <FIG>). By shifting to the low-speed travelling at the stop position identifier <NUM> immediately before the target, it is possible to inhibit passing by the target stop position identifier <NUM>. Furthermore, it is possible to shorten time to reach the target stop position identifier <NUM>. In the present embodiment, the stop position identifier <NUM> immediately before the target is selected as the second stop position identifier, but the stop position identifier <NUM> that is two or more before the target may be selected as the second stop position identifier.

Next, the cart control section <NUM> determines whether or not the target stop position identifier <NUM> is detected (S105). Immediately after detecting the target stop position identifier <NUM> (in other words, immediately after detecting an end part of the stop position identifier <NUM> in the travelling direction), the cart control section <NUM> shifts to deceleration travelling and stops the doffing cart <NUM> (S106, deceleration/stop in <FIG>). A deceleration of the deceleration travelling is calculated in advance. By decelerating with this deceleration and stopping, the doffing cart <NUM> stops at the target stop position. That is, a speed during the low-speed travelling, a position of the doffing cart <NUM> when the optical sensor <NUM> detects the end part of the stop position identifier <NUM> in the travelling direction, and a position of the doffing cart <NUM> for appropriately performing the doffing on the yarn processing unit <NUM> all are known, and thus the deceleration is calculated in advance on the basis of these values.

Note that, instead of the method of calculating the deceleration of the deceleration travelling, a deceleration timing may be calculated with the deceleration being made constant. That is, a distance (a minimum travel distance) traveled until the doffing cart <NUM> stops when decelerating at a constant deceleration from the low-speed travelling can be calculated on the basis of the speed and the deceleration during the low-speed travelling. Therefore, when deceleration is started at a position (a deceleration start position) where a distance to the target stop position becomes equal to the minimum travel distance, the doffing cart <NUM> can be stopped at the target stop position. Specifically, a time from immediately after the target stop position identifier <NUM> is detected until reaching the deceleration start position is calculated in advance, and the cart control section <NUM> starts deceleration of the doffing cart <NUM> after the time from the detection of the stop position identifier <NUM> is elapsed.

However, even when the doffing cart <NUM> is decelerated at the calculated deceleration or deceleration timing, the doffing cart <NUM> may not stop at the target stop position due to control accuracy, inertia, or the like. Therefore, in the present embodiment, after the doffing cart <NUM> is stopped, the cart control section <NUM> determines whether or not a deviation from the target stop position is within a threshold value (S107). This determination is made on the basis of a received light amount detected by the optical sensor <NUM>. That is, the received light amount detected by the optical sensor <NUM> after the doffing cart <NUM> is stopped is compared with the above-described reference received light amount. When a difference is within the threshold value, the cart control section <NUM> ends the cart control, and then performs control related to doffing. The inclined part <NUM> of the stop position identifier <NUM> according to the present embodiment has a constant changing ratio of the length in the detection direction. Therefore, a degree of the deviation from the target stop position can be determined by using the threshold value. In addition, the threshold value is preferably a value larger than a minimum distance in which the doffing cart <NUM> can move when being displaced with respect to the target stop position.

When the difference exceeds the threshold value, the cart control section <NUM> performs position adjustment control (S108). The position adjustment control is control to bring the doffing cart <NUM> close to the target stop position. The inclined part <NUM> of the stop position identifier <NUM> according to the present embodiment has a constant changing ratio of the length in the detection direction. Therefore, by calculating and storing in advance a change amount in the received light amount per unit length in the travelling direction, a length of positional shift of the doffing cart <NUM> can be calculated on the basis of the change amount. The cart control section <NUM> causes the doffing cart <NUM> to travel such that a length of the positional shift of the doffing cart <NUM> approaches <NUM>. For example, when a length of the positional shift is L and a minimum speed of the doffing cart <NUM> is V, the travelling motor <NUM> is driven at the minimum speed for a time corresponding to L/V. Note that the cart control section <NUM> may calculate a driving amount of the travelling motor <NUM> (for example, the number of rotations of an output shaft or a value corresponding thereto) instead of calculating the driving time of the travelling motor <NUM>.

After performing control of stopping the doffing cart <NUM> at the target stop position, the cart control section <NUM> performs communication (for example, wireless communication such as infrared communication) with the yarn processing unit <NUM>, and confirms that the doffing cart <NUM> has arrived in proximity to the target yarn processing unit <NUM>. Thereafter, the cart control section <NUM> performs doffing on the target yarn processing unit <NUM>. The cart control section <NUM> stores identification information of the yarn processing unit <NUM> confirmed here. The identification information of the yarn processing unit <NUM> is used for performing control of travelling to the next target yarn processing unit <NUM>.

In the present embodiment, after position adjustment control, the cart control section <NUM> performs the next processing without redetermining the deviation from the target stop position. Alternatively, the cart control section <NUM> may perform the determination of step S107 again after the position adjustment control, to determine again whether the doffing cart <NUM> has approached the target stop position (whether the deviation from the target stop position is within the threshold value). As a result, the process of readjusting the position of the doffing cart <NUM> (specifically, the processes in steps S107 and S108, hereinafter, referred to as a readjustment process) is repeated until the deviation from the target stop position falls within the threshold value. However, in order to avoid repetition of the readjustment process for a long time, an upper limit may be set to the number of times or a processing time of the readjustment process. When the number of times of the readjustment process exceeds the upper limit (for example, two times) or the processing time exceeds the upper limit, the cart control section <NUM> may abnormally stop the doffing cart <NUM>. Alternatively, the cart control section <NUM> may move the doffing cart <NUM> in a direction away from the target stop position when the number of times of the readjustment process or the processing exceeds the upper limit. In this case, the cart control section <NUM> obtains a travelling time to stop the doffing cart <NUM> at the target stop position, on the basis of a movement amount of the doffing cart <NUM> when separated from the target stop position and the initial deviation. Next, the cart control section <NUM> moves the doffing cart <NUM> according to the travelling time to move the doffing cart <NUM> to the target stop position.

A process of registering a stop position for each yarn processing unit <NUM> will be described.

In the present embodiment, the stop position identifier <NUM> is provided on the rail <NUM>. Whereas, the doffing cart <NUM> performs work on the yarn processing unit <NUM>. A position of the yarn processing unit <NUM> with respect to the rail <NUM> is not necessarily constant due to dimensional accuracy, rattling, deflection, or the like. Therefore, the stop position is preferably registered for each yarn processing unit <NUM>.

<FIG> illustrates exemplification of a method of using a positioning member <NUM>. The positioning member <NUM> is detachably attached to the yarn processing unit <NUM>. When the doffing cart <NUM> and the positioning member <NUM> are brought into contact with each other in a state where the positioning member <NUM> is attached to the yarn processing unit <NUM> (an attaching step), the doffing cart <NUM> is located at a stop position with respect to the yarn processing unit <NUM>. Then, the cart control section <NUM> stores a received light amount detected by the optical sensor <NUM> in this state as a reference received light amount (a storing step). By performing the above process on all the yarn processing units <NUM>, the stop position can be registered for each yarn processing unit <NUM>.

<FIG> illustrates a method of using a positioning sensor <NUM> in addition to the positioning member <NUM>. The positioning sensor <NUM> is provided on the doffing cart <NUM> and moves integrally with the doffing cart <NUM>. The positioning sensor <NUM> is a line sensor whose detection direction is parallel to the travelling direction. The positioning sensor <NUM> is arranged at a position where a characteristic portion (e.g., an edge portion) of the yarn processing unit <NUM> can be detected. Note that the positioning sensor <NUM> may be a sensor (for example, a laser sensor) other than the line sensor as long as the position of the characteristic portion of the yarn processing unit <NUM> can be detected.

First, the positioning sensor <NUM> is attached to the doffing cart <NUM> (a preparing step). Next, the positioning member <NUM> is attached to the yarn processing unit <NUM> similarly to the above, and the doffing cart <NUM> is aligned with the stop position. Then, the cart control section <NUM> stores a received light amount detected by the optical sensor <NUM> in this state as a reference received light amount. Furthermore, the cart control section <NUM> further stores a detection value (specifically, a position of the edge portion of the yarn processing unit <NUM>) detected by the positioning sensor <NUM> in this state. The stored detection value by the positioning sensor <NUM> is a detection value detected when the doffing cart <NUM> is located at the stop position of the yarn processing unit <NUM>. By using the stored detection value by the positioning sensor <NUM>, the positioning member <NUM> does not need to be used for the second and subsequent yarn processing units <NUM>. Specifically, the doffing cart <NUM> is moved to the second yarn processing unit <NUM>, and the doffing cart <NUM> is moved such that the detection value of the positioning sensor <NUM> coincides with the detection value stored in advance. Thereafter, the received light amount detected by the optical sensor <NUM> in this state is stored as a reference received light amount. By performing the above process on all the yarn processing units <NUM>, the stop position can be registered for each yarn processing unit <NUM>.

In the example of <FIG>, for the second and subsequent yarn processing units <NUM>, the doffing cart <NUM> is moved such that the detection value of the positioning sensor <NUM> coincides with the detection value stored in advance. That is, the doffing cart <NUM> is moved with the detection value of the positioning sensor <NUM> as a reference. Alternatively, the doffing cart <NUM> may be moved with the received light amount of the optical sensor <NUM> as a reference. Specifically, when performing processing on the second and subsequent yarn processing units <NUM>, the doffing cart <NUM> is moved such that the received light amount detected by the optical sensor <NUM> coincides with the reference received light amount stored in the first yarn processing unit <NUM>. In this state, a detection value of the positioning sensor <NUM> is acquired. Since a changing ratio of a length of the inclined part <NUM> of the stop position identifier <NUM> in the detection direction is constant, a difference between a detection value of a first positioning sensor <NUM> and a detection value of a second positioning sensor <NUM> corresponds to a difference in the stop position. Therefore, the cart control section <NUM> increases or decreases the reference received light amount by an amount corresponding to this difference. By performing the above process on all the yarn processing units <NUM>, the stop position can be registered for each yarn processing unit <NUM>.

In the present embodiment, since the stop position identifier <NUM> is provided on the rail <NUM>, the stop position for each yarn processing unit <NUM> needs to be registered. Alternatively, as illustrated in <FIG>, the stop position identifier <NUM> may be provided in the yarn processing unit <NUM>. By directly providing on the yarn processing unit <NUM>, the stop position can be determined using manufacturing accuracy of the yarn processing unit <NUM>. Therefore, the stop position can be determined by a common detection value for all the yarn processing units <NUM>. That is, the stop position does not need to be registered for all the yarn processing units <NUM>, and the stop position may be registered for one yarn processing unit <NUM> alone, and information on the stop position may also be used for the remaining yarn processing units <NUM>. In the example illustrated in <FIG>, the stop position identifier <NUM> is provided in the housing <NUM>, but the stop position identifier <NUM> may be provided at a different position in the yarn processing unit <NUM>.

The doffing described above is work on the cradle <NUM>. In addition to this, the doffing cart <NUM> can also perform work of yarn path reference. The work of yarn path reference is, for example, work on a yarn accumulating device when the yarn processing unit <NUM> includes the yarn accumulating device. Since the work on the cradle <NUM> and the work of yarn path reference have different work contents, preferable stop positions of the doffing cart <NUM> may be different. Therefore, by stopping the doffing cart <NUM> at a preferable position according to the work content, even when the doffing cart <NUM> performs work on the same yarn processing unit <NUM>, work efficiency or a work success rate can be improved.

In the configuration of <CIT>, alignment is performed using the index block provided on the rail, but it is difficult to arrange the index block aligned with two adjacent stop positions. Therefore, in the configuration of <CIT>, it is difficult to stop the doffing cart at a preferable position according to the work content. The doffing cart <NUM> of the present embodiment can calculate a relative position of the doffing cart <NUM> with respect to the stop position identifier <NUM> on the basis of a received light amount of the optical sensor <NUM>. Therefore, two adjacent stop positions can be registered, and the doffing cart <NUM> can be stopped at the stop position corresponding to the work content.

For example, by individually performing the method described with reference to <FIG> in accordance with the work content, a plurality of stop positions can be registered for one yarn processing unit <NUM> (one stop position identifier <NUM>). Alternatively, after registering the stop position of reference work (for example, doffing), the plurality of stop positions may be registered for one yarn processing unit <NUM> by increasing or decreasing the stop position of the reference work by a predetermined value.

With reference to <FIG>, a first alternative embodiment in which another identifier is provided in addition to the stop position identifier <NUM> will be described.

In the first alternative embodiment, a length of the optical sensor <NUM> in the detection direction is longer than a length of the stop position identifier <NUM> in the detection direction. Specifically, as illustrated in <FIG>, a detection area of the optical sensor <NUM> is divided into an area A1, an area A2, and an area A3. The area A1, the area A2, and the area A3 are arranged in the detection direction. A length of the area A1 in the detection direction is longer than those of the areas A2 and A3, but may be the same or shorter. The area A1 is an area located at a center in the detection direction. In the area A1 of an installation surface of the rail <NUM>, the stop position identifier <NUM> is provided. The area A2 is an area deviated upward from the area A1. In the area A2 of the installation surface of the rail <NUM>, a yarn processing unit identifier <NUM> and an auxiliary identifier <NUM> are provided. The area A3 is an area deviated downward from the area A1. In the area A3 of the installation surface of the rail <NUM>, a stop position identifier <NUM> indicating information different from that of the auxiliary identifier <NUM> is provided. The yarn processing unit identifier <NUM> may be provided on the yarn processing unit <NUM> (in particular, the housing <NUM>) instead of the rail <NUM>.

The yarn processing unit identifier <NUM>, the auxiliary identifier <NUM>, and the stop position identifier <NUM> are one-dimensional barcodes, and a direction of lines of the one-dimensional barcodes is parallel to the travelling direction. That is, the yarn processing unit identifier <NUM>, the auxiliary identifier <NUM>, and the stop position identifier <NUM> are read in a way of reading different from the stop position identifier <NUM>. Therefore, the cart control section <NUM> can specify an identifier detected by the optical sensor <NUM>, by merely performing simple processing on a received light amount of the optical sensor <NUM>. The optical sensor <NUM> of the first alternative embodiment further has a function of reading a one-dimensional barcode. Further, since the yarn processing unit identifier <NUM>, the auxiliary identifier <NUM>, and the stop position identifier <NUM> are one-dimensional barcodes, the optical sensor <NUM> of the present embodiment can read the yarn processing unit identifier <NUM>, the auxiliary identifier <NUM>, and the stop position identifier <NUM> even while the doffing cart <NUM> is travelling.

The yarn processing unit identifier <NUM> includes identification information of the yarn processing unit <NUM>. The yarn processing unit identifier <NUM> is provided such that a position in the travelling direction is common to the stop position identifier <NUM>. The cart control section <NUM> can specify the yarn processing unit <NUM> near the doffing cart <NUM> on the basis of the yarn processing unit identifier <NUM> read by the optical sensor <NUM>. This enables confirmation that the target yarn processing unit <NUM> has been reached. Note that, in the above-described embodiment, communication is performed with the yarn processing unit <NUM> after the target yarn processing unit <NUM> is reached, to confirm the arrival in proximity to the target yarn processing unit <NUM>. However, in the present alternative embodiment, since the arrival in proximity to the target yarn processing unit <NUM> can be confirmed using the yarn processing unit identifier <NUM>, the communication with the yarn processing unit <NUM> for this confirmation can be omitted.

The auxiliary identifier <NUM> is used for the cart control section <NUM> to calculate a detailed position of the doffing cart <NUM>. The auxiliary identifier <NUM> is provided at each position of sectioning a space between the yarn processing unit identifiers <NUM> into a plurality of (four in the example of <FIG>) pieces. The cart control section <NUM> can calculate a more specific position of the doffing cart <NUM> on the basis of the number of auxiliary identifiers <NUM> that are further read after the yarn processing unit identifier <NUM> is read during travelling. By using the auxiliary identifier <NUM>, it is possible to more appropriately control the acceleration/deceleration of the doffing cart <NUM>. For example, in the above-described embodiment, the shift is made to the low-speed travelling at the stop position identifier <NUM> immediately before the target. However, by using the auxiliary identifier <NUM>, for example, the shift can be made to the low-speed travelling from an intermediate point between the stop position identifier <NUM> immediately before the target and the target stop position identifier <NUM>.

The stop position identifier <NUM> determines a stop position of the doffing cart <NUM> other than the yarn processing unit <NUM>. For example, the stop position identifier <NUM> determines a position of the doffing cart <NUM> when performing maintenance, a position of the doffing cart <NUM> when discarding waste yarns stored in the doffing cart <NUM>, and the like.

Instead of the configuration of the present alternative embodiment, a coordinate value (a value indicating a position in the travelling direction) may be associated with all the yarn processing unit identifiers <NUM> and the auxiliary identifiers <NUM>. The coordinate values corresponding to the yarn processing unit identifier <NUM> and the auxiliary identifier <NUM> are determined in advance and stored in the cart control section <NUM>. In this case, the cart control section <NUM> can specify the position of the doffing cart <NUM> by specifying the yarn processing unit identifier <NUM> or the auxiliary identifier <NUM> on the basis of a received light amount of the optical sensor <NUM> and obtaining the coordinate value corresponding thereto. Furthermore, since the specific coordinate value and the yarn processing unit <NUM> are associated, the yarn processing unit <NUM> can be specified on the basis of the coordinate value specified by the cart control section <NUM>. In this configuration, it is not necessary to count the auxiliary identifier <NUM>.

With reference to <FIG>, a second alternative non-claimed embodiment in which the stop position identifier <NUM> has a different shape will be described.

An optical sensor <NUM> of the second alternative embodiment can detect not only a received light amount but also a light receiving position. Specifically, in the detection area 47a of the optical sensor <NUM>, a plurality of light receiving elements are arranged side by side in the detection direction, and a received light amount of each light receiving element is individually detected. This enables to specify a light receiving position, which is a position where light is detected in the detection area 47a. When the optical sensor <NUM> of this type is used, a length of the stop position identifier <NUM> in the detection direction may be constant as illustrated in <FIG>. A stop position identifier <NUM> of the second alternative embodiment is inclined from one side toward another side in the travelling direction. Therefore, a vertical position of the stop position identifier <NUM> in the detection area 47a in <FIG> differs according to a position of the optical sensor <NUM> in the travelling direction. Therefore, the position of the doffing cart <NUM> with respect to the stop position identifier <NUM> can be calculated on the basis of the light receiving position detected by the optical sensor <NUM>.

With reference to <FIG>, a third alternative non-claimed embodiment in which the stop position identifier <NUM> has a different shape will be described.

An optical sensor <NUM> of the third alternative embodiment measures a distance to an object on the basis of a time taken to radiate and receive light. In a stop position identifier <NUM> of the third alternative embodiment, a thickness in plan view changes depending on a position in the travelling direction. In other words, when the optical sensor <NUM> moves with respect to the stop position identifier <NUM> in the travelling direction, a distance between the optical sensor <NUM> and the stop position identifier <NUM> in plan view changes. Therefore, the position of the doffing cart <NUM> with respect to the stop position identifier <NUM> can be calculated on the basis of the distance (a detection value) detected by the optical sensor <NUM>.

Note that the stop position identifier <NUM> may be a member having a different light reflectance depending on a position. For example, when the light reflectance increases as the optical sensor <NUM> advances in the travelling direction, the position of the doffing cart <NUM> with respect to the stop position identifier <NUM> can be calculated on the basis of the received light amount detected by the optical sensor <NUM>.

With reference to <FIG>, a stop position identifier <NUM> and a yarn processing unit identifier <NUM> in a fourth alternative embodiment will be described.

The stop position identifier <NUM> of the fourth alternative embodiment has the same shape as the stop position identifier <NUM> of the above-described embodiment. The yarn processing unit identifier <NUM> is a portion for identification of the yarn processing unit <NUM>. A shape of the yarn processing unit identifier <NUM> is different at least between adjacent yarn processing units <NUM>. That is, the yarn processing unit identifier <NUM> has at least three types of shapes. The doffing cart <NUM> can confirm that a correct yarn processing unit <NUM> has been reached, by simply analyzing a measurement result of the yarn processing unit identifier <NUM> (without performing the above-described wireless communication and the like).

Specifically, the yarn processing unit identifier <NUM> is an opening formed in the rail <NUM> similarly to the stop position identifier <NUM>. Alternatively, the yarn processing unit identifier <NUM> may have a configuration in which a member having a light reflectance different from that of the rail <NUM> is attached. As illustrated in <FIG>, the yarn processing unit identifier <NUM> has four areas consisting of a first area, a second area, a third area, and a fourth area in order from the bottom, in which an opening is selectively formed in the four areas. The first area is a portion for specifying presence, a position, and the like of the yarn processing unit identifier <NUM>, and an opening is formed in all the yarn processing unit identifiers <NUM>. The second to fourth areas are portions for identification of the yarn processing unit <NUM>, and openings are formed to provide different combinations according to the yarn processing unit <NUM>.

As described above, the automatic winder <NUM> of the above-described embodiment includes the plurality of yarn processing units <NUM>, the doffing cart <NUM>, the stop position identifier <NUM> (or the stop position identifier <NUM>), the optical sensor <NUM>, and the cart control section <NUM>. The yarn processing unit <NUM> winds a yarn around a winding bobbin to form the package <NUM>. The doffing cart <NUM> travels along the travelling direction in a direction in which the yarn processing units <NUM> are arranged as the travelling direction, and performs work on the yarn processing units <NUM>. The stop position identifier <NUM> is provided at a position corresponding to a stop position of the doffing cart <NUM>. The optical sensor <NUM> is provided on the doffing cart <NUM>, and detects the stop position identifier <NUM>. On the basis of magnitude of a detection value or on the basis of a light receiving position that is a position where light is detected in an area (the detection area 47a) where the optical sensor <NUM> can detect the stop position identifier <NUM>, the magnitude of the detection value or the light receiving position being detected by the optical sensor <NUM> with respect to the target stop position identifier <NUM> to stop the doffing cart <NUM>, the cart control section <NUM> calculates a position of the doffing cart <NUM> with respect to the stop position identifier <NUM>, and performs control to stop the doffing cart <NUM> at a stop position of the doffing cart <NUM> determined in advance.

As a result, since the position of the doffing cart <NUM> can be calculated in a non-contact manner, accuracy of the position at which the doffing cart <NUM> is stopped is unlikely to deteriorate. Further, since the position of the doffing cart <NUM> is calculated using the detection value or the light receiving position detected by the optical sensor <NUM>, the position for stopping the doffing cart <NUM> can be adjusted by changing the detection value or the light receiving position for stopping the doffing cart <NUM>.

In the automatic winder <NUM> of the above-described embodiment, the stop position is set for each yarn processing unit <NUM>. The doffing cart <NUM> performs work on the yarn processing unit <NUM> after stopping at the stop position.

This allows the doffing cart <NUM> to perform work with an appropriate positional relationship with respect to the yarn processing unit <NUM>.

In the automatic winder <NUM> of the above-described embodiment, the optical sensor <NUM> is a line sensor.

This makes it possible to acquire more information than a spot-shaped optical sensor <NUM>.

In the automatic winder <NUM> of the above-described embodiment, the detection direction of the line sensor is a direction orthogonal to the travelling direction on the surface provided with the stop position identifier <NUM>.

As a result, by performing detection by the optical sensor <NUM> while travelling, a detection range becomes a planar and wide range.

In the automatic winder <NUM> of the above-described embodiment, a length of the stop position identifier <NUM> in a direction orthogonal to the travelling direction increases, as advancing from one side toward another side in the travelling direction.

This allows calculation of a positional relationship between the optical sensor <NUM> and the stop position identifier <NUM> in the travelling direction.

In the automatic winder <NUM> of the above-described embodiment, an increasing ratio of a length of the stop position identifier <NUM> in the direction orthogonal to the travelling direction is constant.

As a result, a distance in the travelling direction between the optical sensor <NUM> and the stop position identifier <NUM> is proportional to a detection value of the optical sensor <NUM>, which enables calculation of a specific distance between the optical sensor <NUM> and the stop position identifier <NUM>.

In the automatic winder <NUM> of the above-described embodiment, the cart control section <NUM> stores a plurality of stop positions with respect to the stop position identifier <NUM>, and stores any of the plurality of stop positions in association with each work content of the doffing cart <NUM>. The cart control section <NUM> determines the stop position of the doffing cart <NUM> with respect to the stop position identifier <NUM> on the basis of the work content.

This enables the doffing cart <NUM> to be stopped at an appropriate position according to the work content, by using one stop position identifier <NUM>.

In the automatic winder <NUM> of the above-described embodiment, the stop position identifier <NUM> includes: the first stop position identifier as a target to stop the doffing cart <NUM>; and the second stop position identifier selected from the stop position identifiers <NUM> between the doffing cart <NUM> and the first stop position identifier in the travelling direction. The cart control section <NUM> decelerates the doffing cart <NUM> on the basis of detection of the second stop position identifier by the optical sensor <NUM>.

As a result, the doffing cart <NUM> travels at a high speed while being far from the stop position, and travels at a low speed while being close to the stop position, so that the doffing cart <NUM> can reach the stop position in a short time.

In the automatic winder <NUM> of the above-described embodiment, there is provided the yarn processing unit identifier <NUM> that is for identifying the yarn processing unit <NUM> and is provided at a position different from the stop position identifier <NUM> in the direction orthogonal to the travelling direction. A part of the stop position identifier <NUM> overlaps with the yarn processing unit identifier <NUM> in the travelling direction.

This enables to identify the yarn processing unit <NUM> while aligning the stop position by using the optical sensor <NUM> for detection of the stop position. That is, it is possible to confirm that the target yarn processing unit <NUM> has been reached.

In the automatic winder <NUM> of the above-described embodiment, the optical sensor <NUM> reads the yarn processing unit identifier <NUM> in a way different from the stop position identifier <NUM>.

This enables clear distinction between the stop position identifier <NUM> and the yarn processing unit identifier <NUM>.

In the automatic winder <NUM> of the above-described embodiment, the yarn processing unit identifier <NUM> is provided in the yarn processing unit <NUM>.

In the automatic winder <NUM> of the above-described embodiment, the doffing cart <NUM> travels along the rail <NUM>. The stop position identifier <NUM> is an opening formed in the rail <NUM>.

This enables creation of the stop position identifier <NUM> with simple work.

In the automatic winder <NUM> of the above-described embodiment, the stop position identifier <NUM> is provided in the yarn processing unit <NUM>.

This can omit or simplify a process of registering the stop position for each yarn processing unit <NUM> when performing work on the yarn processing unit <NUM>.

In the automatic winder <NUM> of the above-described embodiment, there is provided the auxiliary identifier <NUM> that is for identifying the position of the doffing cart <NUM> in the travelling direction and is provided between the yarn processing units <NUM> in the travelling direction.

This enables more detailed calculation of the position of the doffing cart <NUM>.

A non-claimed teaching method of the above-described embodiment includes an attaching step and a storing step. In the attaching step, the positioning member <NUM> is attached to the yarn processing unit <NUM>. In the storing step, magnitude of a detection value is stored, or a light receiving position that is a position where light is detected in an area (the detection area 47a) where the optical sensor <NUM> can detect the stop position identifier <NUM> is stored, the magnitude of the detection value or the light receiving position being detected by the optical sensor <NUM> with respect to the stop position identifier <NUM> provided at a position corresponding to the stop position of the doffing cart <NUM> in a state where the positioning member <NUM> is in contact with the work cart.

This enables registration of the stop position for each yarn processing unit <NUM>.

The non-claimed teaching method of the above-described embodiment includes a preparing step of attaching the positioning sensor <NUM> to the doffing cart <NUM>. The yarn processing units <NUM> include a first yarn processing unit and a second yarn processing unit. The storing step includes a first storing step and a second storing step. In the first storing step, a detection value or a light receiving position for the first yarn processing unit is stored. In the second storing step, the detection value or the light receiving position for the second yarn processing unit is stored. In the first storing step, in a state where the positioning member <NUM> attached to the first yarn processing unit is in contact with the doffing cart <NUM>, the optical sensor <NUM> detects the detection value or the light receiving position, and the positioning sensor detects the first yarn processing unit. The second storing step is performed after the first storing step. In the second storing step, in a state where the position of the doffing cart <NUM> is aligned with the second yarn processing unit, the stop position of the doffing cart <NUM> with respect to the second yarn processing unit is calculated and stored on the basis of the detection value or the light receiving position detected by the optical sensor <NUM> and on the basis of the position of the second yarn processing unit detected by the positioning sensor <NUM>.

This enables registration of the stop position for the second and subsequent yarn processing units <NUM> without arranging the positioning member in the second and subsequent yarn processing units <NUM>.

Preferred embodiments and alternative embodiments of the present invention have been described above, but the above-described configurations may be modified as below.

In the above-described embodiment, the yarn processing unit identifier <NUM>, the auxiliary identifier <NUM>, and the stop position identifier <NUM> are all one-dimensional barcodes. However, at least any one may have the same configuration (a configuration in which a light reflectance is different from that of an installation surface, for example, a hole) as the stop position identifier <NUM>. In particular, the yarn processing unit identifier <NUM> may have the same shape as the stop position identifier <NUM>. Even if the yarn processing unit identifier <NUM> has the same configuration as the stop position identifier <NUM>, by making a difference in a detection value of the yarn processing unit identifier <NUM> for each yarn processing unit <NUM>, the stop position identifier <NUM> and the yarn processing unit identifier <NUM> can be specified on the basis of a total value of a detection value of the stop position identifier <NUM> and a detection value of the yarn processing unit identifier <NUM>. In other words, as illustrated in <FIG>, when detection values of the stop position identifier <NUM> and the yarn processing unit identifier <NUM> are determined, it can be specified that the doffing cart <NUM> is reading an identifier of an A type when the detected value is <NUM> to <NUM>, the doffing cart <NUM> is reading an identifier of a B type when the detected value is <NUM> to <NUM>, and the doffing cart <NUM> is reading an identifier of a C type when the detected value is <NUM> to <NUM>. In this way, the doffing cart <NUM> can distinguish three types of identifiers. On the basis of this way and the number of stop position identifiers <NUM> by which the doffing cart <NUM> has passed, the doffing cart <NUM> can specify the yarn processing unit <NUM> currently in proximity. Further, when the optical sensor <NUM> capable of detecting the light receiving position is similarly used, the stop position identifier <NUM> and the yarn processing unit identifier <NUM> can be specified by a combination of detection positions of the stop position identifier <NUM> and the yarn processing unit identifier <NUM>.

In the above-described embodiment, the stop position identifier <NUM> is provided on a side surface of the rail <NUM>. Alternatively, the stop position identifier <NUM> may be provided on another surface such as an upper surface of the rail <NUM>.

In the above-described embodiment, the detection direction of the optical sensor <NUM> is a direction orthogonal to the travelling direction. Alternatively, not in accordance with the present invention, when the optical sensor <NUM> capable of detecting a light receiving position is used, the detection direction of the optical sensor <NUM> may be parallel to the travelling direction. In this case, a position (in other words, a relative position of the doffing cart <NUM> with respect to the stop position identifier <NUM>) of the stop position identifier <NUM> in the travelling direction can be specified on the basis of the light receiving position detected by the optical sensor <NUM>. In this way, the doffing cart <NUM> can be stopped at the target stop position on the basis of the detection value of the optical sensor <NUM>.

The flowchart illustrated in the above-described embodiment is an example, and some processes may be omitted, contents of some processes may be changed, or new processes may be added.

In the above-described embodiment, the doffing cart <NUM> has been described as an example of the work cart. Alternatively, the present invention can also be applied to a yarn joining cart.

Claim 1:
A yarn winding machine (<NUM>) comprising:
a plurality of yarn processing units (<NUM>) adapted to wind a yarn around a bobbin to form a package;
a work cart (<NUM>) adapted to travel in a direction in which the yarn processing units (<NUM>) are arranged as a travelling direction, and adapted to perform work on the yarn processing units (<NUM>) ;
a stop position identifier (<NUM>, <NUM>) provided at a position corresponding to a stop position of the work cart (<NUM>);
an optical sensor (<NUM>) provided on the work cart (<NUM>) and adapted to detect the stop position identifier (<NUM>, <NUM>); and
a control section (<NUM>) adapted to calculate a position of the work cart (<NUM>) with respect to the stop position identifier (<NUM>, <NUM>), and perform control to stop the work cart (<NUM>) at a stop position of the work cart (<NUM>) determined in advance, based on magnitude of a detection value or based on a light receiving position that is a position where the stop position identifier (<NUM>, <NUM>) is detected in an area detectable by the optical sensor (<NUM>), the magnitude of the detection value or the light receiving position being detected by the optical sensor (<NUM>) detecting the stop position identifier (<NUM>, <NUM>) as a target to stop the work cart (<NUM>),
characterized in that
the optical sensor (<NUM>) is a line sensor,
wherein a direction of detection by the line sensor is a direction orthogonal to a surface provided with the stop position identifier (<NUM>, <NUM>) and orthogonal to the travelling direction,
wherein on a surface provided with the stop position identifier (<NUM>, <NUM>), in a direction orthogonal to the travelling direction, the stop position identifier (<NUM>, <NUM>) has a longer length on one side than another side in the travelling direction, and
wherein on a surface provided with the stop position identifier (<NUM>, <NUM>), the stop position identifier (<NUM>, <NUM>) has a constant increasing ratio of a length in a direction orthogonal to the travelling direction.