In-out station control method and control system of clothing production hanging equipment

Abstract

The application relates to an in-out station control method and control system of a clothing production hanging device, wherein the control system of the clothing production hanging device comprises a main track, a workstation branch track capable of communicating with the main track, an in-station execution mechanism and an out-station execution mechanism, a plurality of hanging devices are arranged on the main track, the hanging device comprises a push rod and a clothes hanger, an in-station card reader, and an electronic tag with a unique ID code is arranged on each push rod and clothes hanger; characterized in that: each workstation is provided with a workstation control module, the in-station card reader, the in-station execution mechanism and the out-station execution mechanism are in communication connection with the corresponding workstation control module; the in-out station control method of the clothing production hanging device comprises an in-station control method and an out-station control method, the workstation control module controls the in-station and out-station of the clothes hanger through the electronic tag ID code information read by the in-station card reader, and the control mode is simple and low in cost.

Description

Technical Field

[0001] This invention relates to a control method for a garment production line, and more particularly to a control method for the entry and exit of garment production hanging equipment and a control system using the same method. Background Technology

[0002] In recent years, the emergence of hanging production lines in garment manufacturing has completely changed the traditional production model, realizing automated control of the processing process, improving production efficiency, and facilitating production management.

[0003] A garment production hanging assembly line generally includes a closed main track, multiple workstations located below the main track, and a branch track above each workstation that connects to the main track. The entry end of each branch track has an entry actuator that connects to the main track, and the exit end has an exit actuator that connects to the main track. Multiple push rods and hangers are mounted on the main track. Driven by a mechanism, the push rods propel the hangers along the main track in a designated direction. An entry card reader is located on the main track before the entry actuator, and an exit card reader is located on the branch track before the exit actuator. The garment production hanging assembly line also includes a control center. The hangers and push rods are equipped with smart hangers with electronic tags. The control center uses the entry and exit card readers to read the internal information of the electronic tags on the smart hangers to control the actions of the entry and exit actuators. Traditional push rod positioning methods rely on sensor devices such as photoelectric sensors and encoders to calculate the initial position of the overall track push rod and the offset during the movement. This method is costly and computationally complex.

[0004] Chinese invention patent CN 110442101 B (patent number ZL201910724135.5) discloses a method for controlling the exit of a hanging assembly line. This method involves the exit card reader reading hanger information and sending a signal to the control center indicating that a hanger needs to exit. The control center determines whether the push rod passing the entry card reader is empty. If empty, the control information or the communication data controller controls the exit actuator to move the hanger out of the station. The hanger, pushed out of the station by the push rod, moves along the main track. The control center associates the push rod number with the hanger number. Otherwise, the hanger does not exit. After the hanger has exited the station, the exit actuator stops operating. In this scheme, the specific method for determining whether the push bar of the card reader passing through the station is empty is as follows: the card reader reads the push bar number passing through it and uploads it to the main computer in the control center. The main computer in the control center checks whether the push bar number is associated with a hanger number; if not, the push bar is empty; if it is, the main computer in the control center determines whether the hanger associated with the push bar has entered the station; if it has, the push bar is also empty. The above control method has two drawbacks:

[0005] 1. The inbound and outbound card readers, as well as the inbound and outbound actuators, are all connected to the main computer in the control center. The communication links are mostly implemented using RS485 communication technology or CAN bus communication with the host computer. This communication mode has drawbacks such as low communication distance, low speed, and low bandwidth, making it unsuitable for long-distance, high-data-volume communication and unable to handle large file transfers such as video. Furthermore, significant delays can easily occur in the uploading and downloading of communication information. In particular, if any one of the card readers malfunctions, it will cause chaos in the control of the push rods and hangers throughout the entire production line.

[0006] 2. The specific method for determining whether the push bar passing the card reader at the station is empty is as follows: The main circuit of the control center queries whether the "push bar number" and the "clothes hanger number" are associated and bound together, or whether the clothes hanger of the "clothes hanger number" associated with a certain "push bar number" has entered the station. This method of determining whether the push bar is empty is too complicated, and due to the possible large "delay" in the communication method, the uploading and downloading of information may not be timely. It is easy for an "empty push bar" to have passed the exit of the work station's support track, but the clothes hanger has not left the station in time. When the clothes hanger leaves the station, the next push bar it encounters happens to be a "non-empty" push bar. This will result in a "chaotic" situation where one push bar drives two clothes hangers.

[0007] 3. The timing control of the "clothes hanger" exiting the station is not accurate enough: When the exit card reader reads the clothes hanger information, the clothes hanger is located near the exit card reader. At this time, the exit card reader sends the information "clothes hanger needs to exit" to the main computer of the control center. Then, the main computer of the control center determines whether the push rod passing the entry card reader is empty. If it is empty, the control information control or the communication data controller controls the exit actuator to drive the clothes hanger out of the station. However, there is often a certain distance between the entry card reader and the exit of the work station branch track. The push rod needs a certain amount of time to travel over this distance. This control method is also prone to the above-mentioned "empty push rod" having passed the exit of the work station branch track, but the clothes hanger has not exited the station in time. When the clothes hanger exits the station, the next push rod it encounters happens to be a "non-empty" push rod. This will result in a "chaotic" situation where one push rod drives two clothes hangers.

[0008] Therefore, the existing technology needs further improvement. Summary of the Invention

[0009] The primary technical problem to be solved by this invention is to provide a simple and low-cost method for controlling the entry and exit of garment production hanging equipment, which is in contrast to the above-mentioned prior art.

[0010] The further technical problem to be solved by the present invention is to provide an entry and exit control system for garment production hanging equipment that is simple to control and low in cost, in contrast to the above-mentioned prior art.

[0011] The technical solution adopted by this invention to solve the aforementioned primary technical problem is as follows: a method for controlling the entry and exit of garment production hanging equipment, wherein the garment production hanging equipment control system includes a main track, multiple workstations below the main track, and a workstation branch track above each workstation that can communicate with the main track. The entry end of the workstation branch track is equipped with a rotatable entry swing head, which is driven and connected to an entry actuator. The entry actuator can drive the entry swing head to rotate, thereby connecting the entry end of the workstation branch track to the main track. The exit end of the workstation branch track is equipped with a rotatable exit swing head, which is driven and connected to an exit actuator. The exit actuator can drive the exit swing head to rotate, thereby connecting the exit end of the workstation branch track to the main track. Multiple hanging devices are installed on the main track, each hanging device including a push rod and a garment hanger. The push rod can be driven by a drive mechanism... The clothes hangers on the main track are pushed and run in a designated direction along the main track; each workstation branch track is equipped with an entry card reader on the main track in front of the entry end, and each push rod and clothes hanger is equipped with an electronic tag with a unique ID code; the key feature is that each workstation is equipped with a workstation control module, the corresponding entry card reader on the main track in front of the entry end of each workstation branch track is communicatively connected to the corresponding workstation control module, and the entry execution mechanism corresponding to the entry end of each workstation branch track, and the exit execution mechanism corresponding to the exit end of each workstation branch track are all communicatively connected to the corresponding workstation control module; each workstation control module pre-stores the electronic tag ID codes of all push rods and the electronic tag ID codes of the clothes hangers required for this workstation; the entry and exit control method of the garment production hanging equipment includes an entry control method and an exit control method;

[0012] The entry control method of the entry and exit control method includes: whenever the entry card reader reads a new electronic tag ID code, it sends the electronic tag ID code to the corresponding workstation control module. The workstation control module determines whether the electronic tag ID code is the electronic tag ID code of the hanger that needs to enter the workstation. If so, the hanging device corresponding to the electronic tag ID code is the hanger that needs to enter the workstation. At this time, the workstation control module controls the corresponding entry actuator to connect the entry end of the workstation branch track to the main track, so that the hanger corresponding to the electronic tag ID code enters the workstation branch track. If not, the entry card reader continues to read the next new electronic tag ID code and repeats the judgment.

[0013] The exit control method of the entry and exit control method includes: when there is a hanger waiting to exit on the workstation branch track, the workstation control module continuously determines whether the hanging device passing the entry card reader is an "idle push rod". If it is an "idle push rod", when the "idle push rod" moves close to the exit end of the workstation branch track, the workstation control module controls the corresponding exit execution mechanism to connect the exit end of the workstation branch track with the main track, so that the hanger waiting to exit on the workstation branch track enters the main track and is located in front of the "idle push rod".

[0014] As an improvement, the workstation control module determines whether the hanging device passing the inbound card reader is an "idle push bar" as follows: The inbound card reader continuously reads the electronic tag ID code of each hanging device passing the inbound card reader and sends the read electronic tag ID code to the workstation control module. Each time the workstation control module receives an electronic tag ID code, it performs the following steps to determine its status:

[0015] Step 1: Determine if the electronic tag ID code is the same as the electronic tag ID code of the hanger. If it is, record the time when the card reader reads the electronic tag ID code and proceed to Step 2. If it is not the electronic tag ID code of the hanger, the hanging device corresponding to the electronic tag ID code is a push rod and proceed to Step 3.

[0016] Step 2: The workstation control module continues to determine whether the electronic tag ID code is the electronic tag ID code of the hanger required by this workstation. If the electronic tag ID code is the electronic tag ID code of the hanger required by this workstation, the workstation control module controls the corresponding entry actuator to connect the entry end of the workstation branch track with the main track, so that the hanger corresponding to the electronic tag ID code enters the workstation branch track; if the electronic tag ID code is not the electronic tag ID code of the hanger required by this workstation, the electronic tag ID code is ignored.

[0017] Step 3: The workstation control module subtracts the time when the electronic tag ID code is read from the time when the most recent electronic tag ID code of the hanger is obtained to get Δt3. It then compares the shortest distance between two adjacent push rods on the main track with the running speed of the push rods on the main track to get Δt. It then determines whether Δt3 is less than Δt. If so, proceed to step 4; otherwise, set the hanging device where the electronic tag ID code is located as an "idle push rod".

[0018] Step 4: The workstation control module determines whether the hanger corresponding to the electronic tag ID code of the hanger closest to the electronic tag ID acquisition time has entered this workstation. If not, the hanging device where the electronic tag ID code is located is set as "busy push bar". If so, the hanging device where the electronic tag ID code is located is set as "idle push bar".

[0019] Further improvements are made. When the workstation control module determines that the hanging device corresponding to a certain electronic tag ID code is the electronic tag ID code of the hanger that needs to enter the workstation, the workstation control module obtains the entry waiting time required for the hanger to enter the station by the ratio of the distance between the entry card reader and the entry execution mechanism to the running speed of the main track push rod. After the entry waiting time expires, the workstation control module controls the entry execution mechanism to connect the entry end of the workstation branch track to the main track, so that the hanger corresponding to the electronic tag ID code enters the workstation branch track.

[0020] Further improvements are made when a hanger awaiting exit is placed on the workstation branch track, and the workstation control module determines that the hanging device currently passing the entry card reader is an "idle push rod". The workstation control module obtains the exit waiting time for the "idle push rod" to reach the exit end of the workstation branch track by using the ratio of the distance between the entry card reader and the exit end of the corresponding workstation branch track to the running speed of the push rod driven by the main track. Based on this exit waiting time, the workstation control module controls the corresponding exit actuator to connect the exit end of the workstation branch track with the main track, so that the hanger awaiting exit on the workstation branch track enters the main track and is positioned in front of the "idle push rod".

[0021] The technical solution adopted by the present invention to solve the above-mentioned further technical problems is: a garment production hanging equipment control system, characterized in that: the above-mentioned garment production hanging equipment control system adopts the above-mentioned entry and exit control method for garment production hanging equipment control system for operation control.

[0022] Compared with the prior art, the advantages of the present invention are as follows: Each workstation is equipped with a workstation control module. This workstation control module only needs to focus on the electronic tag ID code information read by the corresponding entry card reader on the main track on the front side of the entry end of the workstation's support track. It can then control entry and exit based on the read electronic tag ID code. In the improved scheme for determining whether the hanging equipment currently passing the entry card reader is an "idle push rod", the distance between the hanging equipment where two adjacent electronic tags are located is compared with the shortest distance between two push rods on the main track to infer whether there is an "idle push rod". The determination method is simple, does not require the setting of an exit card reader, and has low cost. Attached Figure Description

[0023] Figure 1 This is a block diagram of the control system for garment production hanging equipment in an embodiment of the present invention.

[0024] Figure 2 This is a flowchart of the entry and exit control method for garment production hanging equipment in an embodiment of the present invention. Detailed Implementation

[0025] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0026] like Figure 1 The garment production hanging equipment control system shown includes a generally enclosed main track 1. Multiple workstations 2 are located below the main track 1, and each workstation 2 has a workstation branch track 3 above it that connects to the main track. The entry end of each workstation branch track 3 has a rotatable entry swing head 10, which is driven by an entry actuator 4. The entry actuator drives the entry swing head 10 to rotate, thus connecting the entry end of the workstation branch track 3 to the main track 1. The exit end of each workstation branch track has an exit swing head 9, which is driven by an exit actuator 5. The exit actuator 5 drives the exit swing head 9 to rotate, thus connecting the exit end of the workstation branch track 3 to the main track 1. Multiple hanging devices are installed on the main track 1, including push rods 6 and garment hangers 7. The push rods 6 can drive... Driven by the mechanism, the clothes hangers on the main track 1 are pushed to run in the designated direction on the main track 1. Each workstation branch track 3 has an entry card reader 8 on the main track 1 at its entry end, and each push rod and clothes hanger has an electronic tag with a unique ID code. Each workstation 2 has a workstation control module 21. The corresponding entry card reader 8 on the main track at the entry end of each workstation branch track is communicatively connected to the corresponding workstation control module 21. Furthermore, the entry execution mechanism 4 at the entry end of each workstation branch track 3 and the exit execution mechanism 5 at the exit end of each workstation branch track are also communicatively connected to the corresponding workstation control module 21. Each workstation control module pre-stores the electronic tag ID codes of all push rods and the electronic tag ID codes of the clothes hangers required for that workstation. The entry execution mechanism 4, exit execution mechanism 5, and drive mechanism utilize existing conventional technology. Each workstation's corresponding workstation control module 21 is connected to the host computer in the main control center. The electronic tag ID codes of all push rods and the electronic tag ID codes of the clothes hangers required for this workstation are pre-stored in the workstation control module 21. These can be sent in advance by the host computer in the main control center or entered individually on the workstation control module 21. In addition, each workstation's corresponding workstation control module 21 stores the shortest distance L between two adjacent push rods on the main track, the running speed V of the main track pushing the push rods, the distance L1 between the corresponding entry card reader 8 and the entry end of the corresponding workstation branch track 3 on the main track 1 in front of the entry end of each workstation branch track 3, and the distance L2 between the corresponding entry card reader 8 and the exit end of the corresponding workstation branch track 3. This data can be sent in advance by the host computer in the main control center or entered individually on the workstation control module 21.

[0027] The above-mentioned garment production hanging equipment control system includes an entry control method and an exit control method for each workstation hanger. The workstation control module 21 in each workstation 2 will run the above-mentioned entry and exit control methods. When each workstation control module executes the entry control method and the exit control method, the two control methods run independently at the same time and do not affect each other.

[0028] The entry control method in the entry and exit control method includes: the entry card reader continuously reads the electronic tag ID code of each hanging device that passes through the entry card reader, and sends the read electronic tag ID code to the workstation control module. Each time the workstation control module receives an electronic tag ID code, it performs the following steps to determine whether the electronic tag ID code belongs to the hanger that needs to enter the workstation. If so, the hanging device corresponding to the electronic tag ID code is the hanger that needs to enter the workstation. At this time, the workstation control module obtains the waiting time △t1 required for the hanger to enter the station by the ratio of the distance between the entry card reader and the corresponding entry end of the workstation support rail 3 to the running speed of the main rail push rod. After the waiting time △t1 expires, the workstation control module controls the entry execution mechanism to work. The entry execution mechanism 4 drives the entry swing head 10 to rotate and connect the entry end of the workstation support rail to the main rail, so that the hanger corresponding to the electronic tag ID code enters the workstation support rail; otherwise, the workstation control module performs the judgment of the next electronic tag ID code.

[0029] The exit control method in the entry and exit control method includes: a hanger exit touch switch can be installed in the workstation, and the hanger exit touch switch is communicatively connected to the workstation control module 21. When the hanger exit touch switch is triggered, the workstation control module 21 can know that there is a hanger waiting to exit on the workstation support rail. When there is a hanger waiting to exit on the workstation support rail, the workstation control module continuously judges whether the hanging device passing the entry card reader is an "idle push rod". If it is an "idle push rod", the workstation control module will proceed through the entry rail. The ratio of the distance between the card reader and the exit end of the corresponding workstation branch track to the running speed of the main track push rod determines the exit waiting time △t2 when the "idle push rod" reaches the exit end of the workstation branch track. Based on the exit waiting time △t2, the workstation control module 21 controls the corresponding exit execution mechanism 5 to work. The exit execution mechanism 5 drives the exit swing head 9 to rotate and connect the exit end of the workstation branch track with the main track, so that the clothes hanger 7 waiting to exit on the workstation branch track enters the main track and is located in front of the "idle push rod".

[0030] The workstation control module determines whether a suspended device passing through the inbound card reader is an "idle push bar" as follows: The inbound card reader continuously reads the electronic tag ID code of each suspended device passing through the inbound card reader and sends the read electronic tag ID code to the workstation control module. Each time the workstation control module receives an electronic tag ID code, it performs the following steps to determine its validity:

[0031] Step 1: Determine if the electronic tag ID code is the same as the electronic tag ID code of the hanger. If it is, record the time when the card reader reads the electronic tag ID code and proceed to Step 2. If it is not the electronic tag ID code of the hanger, the hanging device corresponding to the electronic tag ID code is a push rod and proceed to Step 3.

[0032] Step 2: The workstation control module continues to determine whether the electronic tag ID code is the electronic tag ID code of the hanger required by this workstation. If the electronic tag ID code is the electronic tag ID code of the hanger required by this workstation, the workstation control module controls the corresponding entry actuator to connect the entry end of the workstation branch track with the main track, so that the hanger corresponding to the electronic tag ID code enters the workstation branch track; if the electronic tag ID code is not the electronic tag ID code of the hanger required by this workstation, the electronic tag ID code is ignored.

[0033] Step 3: The workstation control module subtracts the time when the electronic tag ID code is read from the time when the most recent electronic tag ID code of the hanger is obtained to get Δt3. It then compares the shortest distance between two adjacent push rods on the main track with the running speed of the push rods on the main track to get Δt. It then determines whether Δt3 is less than Δt. If so, proceed to step 4; otherwise, set the hanging device where the electronic tag ID code is located as an "idle push rod".

[0034] Step 4: The workstation control module determines whether the hanger corresponding to the electronic tag ID code of the hanger closest to the electronic tag ID acquisition time has entered this workstation. If not, the hanging device where the electronic tag ID code is located is set as "busy push bar". If so, the hanging device where the electronic tag ID code is located is set as "idle push bar".

[0035] The entry and exit control method in this embodiment does not require the setting of an exit card reader. Each workstation control module operates independently and does not need to communicate with the host computer in the control center, which can ensure good real-time performance. The control method is simple, reliable, and low in cost.

Claims

1. A method for controlling the entry and exit of garment production hanging equipment, wherein the garment production hanging equipment control system includes a main track, multiple workstations below the main track, and a workstation branch track above each workstation that can communicate with the main track. The entry end of the workstation branch track is equipped with a rotatable entry swing head, which is driven and connected to an entry actuator. The entry actuator can drive the entry swing head to rotate, thereby connecting the entry end of the workstation branch track to the main track. The exit end of the workstation branch track is equipped with a rotatable exit swing head, which is driven and connected to an exit actuator. The exit actuator can drive the exit swing head to rotate, thereby connecting the exit end of the workstation branch track to the main track. Multiple hanging devices are installed on the main track, each including a push rod and a hanger. The push rod, driven by a drive mechanism, pushes the hanger on the main track to run in a specified direction on the main track. An entry card reader is installed on the main track in front of the entry end of each workstation branch track, and each push rod and hanger is equipped with an electronic tag with a unique ID code. The method is characterized by: Each workstation is equipped with a workstation control module. The corresponding entry card reader on the main rail at the front of the entry end of each workstation's branch rail is communicatively connected to the corresponding workstation control module. Furthermore, the entry actuator at the entry end of each workstation's branch rail and the exit actuator at the exit end of each workstation's branch rail are also communicatively connected to the corresponding workstation control module. Each workstation control module pre-stores the electronic tag ID codes of all push rods and the electronic tag ID codes of the hangers required for this workstation. The entry and exit control methods for the garment production hanging equipment include an entry control method and an exit control method. The entry control method of the entry and exit control method includes: whenever the entry card reader reads a new electronic tag ID code, it sends the electronic tag ID code to the corresponding workstation control module. The workstation control module determines whether the electronic tag ID code is the electronic tag ID code of the hanger that needs to enter the workstation. If so, the hanging device corresponding to the electronic tag ID code is the hanger that needs to enter the workstation. At this time, the workstation control module controls the corresponding entry actuator to connect the entry end of the workstation branch track to the main track, so that the hanger corresponding to the electronic tag ID code enters the workstation branch track. If not, the entry card reader continues to read the next new electronic tag ID code and repeats the judgment. The exit control method of the entry and exit control method includes: when there is a hanger waiting to exit on the workstation branch track, the workstation control module continuously determines whether the hanging device passing the entry card reader is an "idle push rod". If it is an "idle push rod", when the "idle push rod" moves close to the exit end of the workstation branch track, the workstation control module controls the corresponding exit execution mechanism to connect the exit end of the workstation branch track with the main track, so that the hanger waiting to exit on the workstation branch track enters the main track and the hanger is located in front of the "idle push rod". The workstation control module determines whether a suspended device passing through the inbound card reader is an "idle push bar" as follows: The inbound card reader continuously reads the electronic tag ID code of each suspended device passing through the inbound card reader and sends the read electronic tag ID code to the workstation control module. Each time the workstation control module receives an electronic tag ID code, it performs the following steps to determine its validity: Step 1: Determine if the electronic tag ID code is the same as the electronic tag ID code of the hanger. If it is, record the time when the card reader reads the electronic tag ID code and proceed to Step 2. If it is not the electronic tag ID code of the hanger, the hanging device corresponding to the electronic tag ID code is a push rod and proceed to Step 3. Step 2: The workstation control module continues to determine whether the electronic tag ID code is the electronic tag ID code of the hanger required by this workstation. If the electronic tag ID code is the electronic tag ID code of the hanger required by this workstation, the workstation control module controls the corresponding entry actuator to connect the entry end of the workstation branch track with the main track, so that the hanger corresponding to the electronic tag ID code enters the workstation branch track; if the electronic tag ID code is not the electronic tag ID code of the hanger required by this workstation, the electronic tag ID code is ignored. Step 3: The workstation control module subtracts the time when the electronic tag ID code is read from the time when the most recent electronic tag ID code of the hanger is obtained to get Δt3. It then compares the shortest distance between two adjacent push rods on the main track with the running speed of the push rods on the main track to get Δt. It then determines whether Δt3 is less than Δt. If so, proceed to step 4; otherwise, set the hanging device where the electronic tag ID code is located as an "idle push rod". Step 4: The workstation control module determines whether the hanger corresponding to the electronic tag ID code of the hanger closest to the electronic tag ID acquisition time has entered this workstation. If not, the hanging device where the electronic tag ID code is located is set as "busy push bar". If so, the hanging device where the electronic tag ID code is located is set as "idle push bar".

2. The method for controlling the entry and exit of garment production hanging equipment according to claim 1, characterized in that: When the workstation control module determines that the hanging device corresponding to a certain electronic tag ID code is the electronic tag ID code of the hanger required by this workstation, the workstation control module obtains the entry waiting time required for the hanger to enter the station by using the ratio of the distance between the entry card reader and the entry end of the corresponding workstation branch track to the running speed of the main track push rod. After the entry waiting time expires, the workstation control module controls the entry actuator to connect the entry end of the workstation branch track with the main track, so that the hanger corresponding to the electronic tag ID code enters the workstation branch track.

3. The method for controlling the entry and exit of garment production hanging equipment according to claim 1, characterized in that: When a hanger awaiting exit is placed on the workstation branch track, and the workstation control module determines that the hanging device currently passing the entry card reader is an "idle push rod," the workstation control module uses the ratio of the distance between the entry card reader and the corresponding exit end of the workstation branch track to the running speed of the push rod driven by the main track to determine the exit waiting time for the "idle push rod" to reach the exit end of the workstation branch track. Based on this exit waiting time, the workstation control module controls the corresponding exit actuator to connect the exit end of the workstation branch track with the main track, allowing the hanger awaiting exit on the workstation branch track to enter the main track and position the hanger in front of the "idle push rod." 4. A control system for garment production hanging equipment, characterized in that: Operation control is performed using any one of the entry / exit control methods described in claims 1 to 3.

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