Large electrically-driven rectangular vacuum gate valve and motion control method
Technical Field
The invention relates to the field of pneumatic test equipment, in particular to a large-scale electrically-driven rectangular vacuum gate valve and a motion control method.
Background
In pneumatic test equipment, some tests need to be carried out in a large vacuum cavity, and the vacuum degree in the vacuum cavity is maintained by means of the suction action of an injection system. The area of an airflow channel of the vacuum cavity is large, the airflow channel is rectangular, after the test is started, the vacuum gate valve needs to be opened at a high speed without impact, the vacuum gate valve needs to be closed at a high speed without impact after the test is finished, and the vacuum cavity is required to be sealed reliably after the vacuum gate valve is closed, so that the test result of the optical test equipment is not influenced. The traditional vacuum gate valve is small in caliber, a flow channel is generally circular, a high-pressure gas driving mode is adopted for realizing quick opening and closing, the opening and closing speed of the mode can meet the test requirement, but the vibration impact is very large, the service life is short, and the requirement of the test on the vibration characteristic of the valve cannot be met.
Disclosure of Invention
The invention aims to provide a technical scheme of a large electrically-driven rectangular vacuum gate valve and a motion control method aiming at the defects in the prior art, the scheme adopts a servo motor for driving and combines a specially developed motion control method, so that the high-speed impact-free opening and closing of the vacuum gate valve can be realized, the scheme is suitable for large-caliber vacuum gate valves, the test requirement of high-speed opening and closing is met, and the service life of equipment can be effectively prolonged.
The scheme is realized by the following technical measures:
a large-scale electrically-driven rectangular vacuum gate valve comprises a driving mechanism, a valve body, a connecting mechanism, a flow channel baffle, a sealing mechanism and a limiting block; an airflow channel is arranged on the side wall of the valve body; the driving mechanism is arranged at the top of the valve body; the flow channel baffle is arranged inside the valve body; the connecting mechanism connects the flow channel baffle with the driving mechanism; the sealing mechanism is arranged on the connecting mechanism; the limiting block is arranged inside the valve body; the driving mechanism can drive the connecting mechanism to do telescopic motion in the vertical direction; when the connecting mechanism descends to the limit position, the sealing mechanism can seal the air flow channel of the valve body under the action of the limiting block to realize the closed circuit of the air path; when the connecting mechanism moves upwards to the limit position, the position of the flow channel baffle is matched with the position of the airflow channel to realize an open circuit of the air path.
The scheme is preferably as follows: the connecting mechanism is a connecting rod.
The scheme is preferably as follows: the sealing mechanism comprises a swing rod, a sealing cover plate and a stop wheel; the swing rod is respectively movably connected with the connecting mechanism and the sealing cover plate; the stop wheel is arranged on the side surface of the sealing cover plate and is matched with the position of the limiting block; when the connecting mechanism moves upwards to the limit position, the sealing cover plate is in a free contraction state; when the connecting mechanism moves downwards to the limit position, the stop wheel contacts with the limiting block, so that the sealing cover plate is in an extending state, and the sealing cover plate can completely block the airflow channel of the valve body.
The scheme is preferably as follows: the driving mechanism comprises an alternating current servo motor, an electric cylinder and a motion control system; the alternating current servo motor can drive the electric cylinder to move; the electric cylinder is connected with the connecting mechanism; the motion control system can control the work of the alternating current servo motor; the motion control system selects S7-1500T series of Siemens motion control series PLC, and configures a Profibus DP bus interface; the AC servo motor is provided with an absolute encoder.
A motion control method based on the vacuum gate valve is characterized by comprising the following steps: the method comprises the following steps:
a. presetting a valve opening and closing process, and creating a connecting rod motion curve graph;
b. the cam table is created by programming software, and the cam curve is constructed, so that the connecting rod motion curve graph is synchronous with the cam curve.
The scheme is preferably as follows: in the step a, the opening and closing process of the valve is as follows:
and (3) valve closing process: the servo motor is started, firstly, the speed is increased to enable the connecting rod to move downwards until the connecting rod reaches the designated speed, then, the speed is reduced to 0 when the stopping wheel is positioned at the position above the limiting block and at the preset distance until the stopping wheel is contacted with the limiting block, and then, the connecting rod stops when the connecting rod extends out of the limit position according to the trapezoidal speed;
the valve closing process is the reverse motion of the valve opening process.
The scheme is preferably as follows: the concrete implementation method of the step b is as follows:
the concrete implementation method of the step b is as follows:
firstly, completing project configuration according to control system hardware equipment and network configuration;
two process objects are created in the control software design: one is a linear virtual axis as the active axis; the other is a connecting rod driven by an alternating current servo motor and used as a synchronous driven shaft, the shaft type is set to be a linear shaft, and an absolute encoder is adopted to obtain the shaft coordinate position of the connecting rod;
creating a cam table by using a cam editor of a programming software process object, constructing a cam curve, and adding cam elements in graphs and tables; an electronic cam curve established by motion control is mainly based on a connecting rod motion curve graph, the motion range of the horizontal and vertical coordinates of the electronic cam curve selects a valve minimum position S1 to a full-open position S7, the positions S1 to S7 are positions of speed inflection points corresponding to a connecting rod when an imaginary axis moves at a constant speed, a transition part between cam elements is interpolated by using a B spline, the motion ranges of the imaginary axis and the connecting rod are consistent, namely 0 to S7, and the electronic cam curve is named as camX after the cam is successfully established;
reading a current connecting rod position value, obtaining a virtual shaft position value corresponding to the current connecting rod position value on a cam camX relation curve by using an MC _ GetCamLeadingValue instruction, enabling a virtual shaft and a connecting rod by adopting an MC _ Power instruction and enabling a parameter ENABLE to take 1, and positioning the virtual shaft to a position corresponding to the current connecting rod position by adopting an MC _ MoveAbsolute instruction;
coupling the virtual axis and the connecting rod by using an MC _ CamIn motion control instruction, starting a cam curve camX of the virtual axis and the connecting rod, synchronizing the corresponding relation of the cam camX between the virtual axis and the connecting rod, and immediately starting synchronization when the parameter SyncProfileReference value takes 3;
when the valve is opened, the MC _ MoveAbsolute command is adopted to control the virtual axis so as to
Moves from 0 to the S7 position; when the valve is closed, the MC _ MoveAbsolute command is adopted to control the virtual axis so as to
Moves from the S7 to the 0 position;
after the task is completed, the MC _ Power instruction is adopted, the ENABLE parameter is 0, and the virtual shaft and the connecting rod are disabled.
The beneficial effects of the scheme can be known from the description of the scheme, because the scheme adopts an alternating current servo valve synchronous motor driving mode, a motion control system, a virtual shaft, a cam relation curve of the virtual shaft and the connecting rod and a master-slave linkage control mode through the sealing cover plate, the flow channel baffle plate, the swing rod, the connecting rod and the stop wheel motion mechanism, and realizes high-speed vibration-free and impact-free opening and closing of the large-scale electrically-driven rectangular vacuum gate valve.
Therefore, compared with the prior art, the invention has prominent substantive features and remarkable progress, and the beneficial effects of the implementation are also obvious.
Drawings
Fig. 1 is a schematic structural view of the valve of the present invention in an open state.
Fig. 2 is a schematic structural view of the valve of the present invention in a closed state.
Fig. 3 is a graph of the connecting rod movement.
Fig. 4 is a diagram of an electronic cam curve parameterization element selection point.
In the figure, 1 is an alternating current servo motor, 2 is an electric cylinder, 3 is a valve body, 4 is a sealing cover plate, 5 is a stop wheel, 6 is a swing rod, 7 is a connecting rod, 8 is a flow channel baffle, 9 is a limiting block, and 10 is an air flow channel.
Detailed Description
All of the features disclosed in this specification, or all of the steps in any method or process so disclosed, may be combined in any combination, except combinations of features and/or steps that are mutually exclusive.
Any feature disclosed in this specification (including any accompanying claims, abstract and drawings), may be replaced by alternative features serving equivalent or similar purposes, unless expressly stated otherwise. That is, unless expressly stated otherwise, each feature is only an example of a generic series of equivalent or similar features.
Example (b):
in this embodiment, the vacuum gate valve includes a driving mechanism, a valve body, a connecting mechanism, a flow channel baffle, a sealing mechanism and a limiting block; an airflow channel is arranged on the side wall of the valve body; the driving mechanism is arranged at the top of the valve body; the flow channel baffle is arranged inside the valve body; the connecting mechanism connects the flow channel baffle with the driving mechanism; the sealing mechanism is arranged on the connecting mechanism; the limiting block is arranged inside the valve body; the driving mechanism can drive the connecting mechanism to do telescopic motion in the vertical direction; when the connecting mechanism moves downwards to the limit position, the sealing mechanism can seal the airflow channel of the valve body under the action of the limiting block to realize the closed circuit of the air path (as shown in fig. 2); when the connecting mechanism moves upwards to the limit position, the position of the flow channel baffle is matched with the position of the airflow channel to realize an open-circuit of the air path (as shown in figure 1).
The connecting mechanism is a connecting rod.
The sealing mechanism comprises a swing rod, a sealing cover plate and a stop wheel; the swing rod is respectively movably connected with the connecting mechanism and the sealing cover plate; the stop wheel is arranged on the side surface of the sealing cover plate and is matched with the position of the limiting block; when the connecting mechanism moves upwards to the limit position, the sealing cover plate is in a free contraction state; when the connecting mechanism moves downwards to the limit position, the stop wheel contacts with the limiting block, so that the sealing cover plate is in an extending state, and the sealing cover plate can completely block the airflow channel of the valve body.
The driving mechanism comprises an alternating current servo motor, an electric cylinder and a motion control system; the alternating current servo motor can drive the electric cylinder to move; the electric cylinder is connected with the connecting mechanism; the motion control system can control the work of the alternating current servo motor; the motion control system selects the S7-1500T series of Siemens motion control series PLC, configures a Profibus DP bus interface, and the vacuum gate valve driving motor selects a 1FT series permanent magnet synchronous servo motor with compact Siemens structure and good dynamic response, and is provided with an absolute encoder for marking the valve switch position and participating in the speed and position control of the vacuum gate valve;
the motion control method of the vacuum gate valve is characterized by comprising the following steps: the method comprises the following steps:
a. presetting the opening and closing process of a valve, and creating a connecting rod motion curve diagram (shown in figure 3);
b. the cam curve is constructed by programming software to create a cam table (see table 1) that synchronizes the control link motion profile with the cam curve.
In the step a, the opening and closing process of the valve is as follows:
and (3) a valve closing process: the servo motor is started, firstly, the speed is increased to enable the connecting rod to move downwards until the connecting rod reaches the designated speed, then, the speed is reduced to 0 when the stopping wheel is positioned at the position above the limiting block at the preset distance until the stopping wheel is contacted with the limiting block, and then, the connecting rod stops when the connecting rod extends out of the limit position according to the trapezoidal speed.
The valve opening process is the reverse motion of the valve opening process.
The concrete implementation method of the step b is as follows:
the concrete implementation method of the step b is as follows:
firstly, completing project configuration according to control system hardware equipment and network configuration;
two process objects are created in the control software design: one is a linear virtual axis as a driving axis; the other is a connecting rod driven by an alternating current servo motor and used as a synchronous driven shaft, the shaft type is set to be a linear shaft, and an absolute encoder is adopted to obtain the shaft coordinate position of the connecting rod;
creating a cam table by using a cam editor of a programming software process object, constructing a cam curve, and adding cam elements in graphs and tables; an electronic cam curve established by motion control is mainly based on a connecting rod motion curve graph, the motion range of the horizontal and vertical coordinates of the electronic cam curve selects a valve minimum position S1 to a full-open position S7, the positions S1 to S7 are positions of speed inflection points corresponding to a connecting rod when an imaginary axis moves at a constant speed, a transition part between cam elements is interpolated by using a B spline, the motion ranges of the imaginary axis and the connecting rod are consistent, namely 0 to S7, and the electronic cam curve is named as camX after the cam is successfully established;
reading a current connecting rod position value, obtaining a virtual axis position value corresponding to the current connecting rod position value on a cam camX relation curve by using an MC _ GetCamLeadingValue instruction, enabling a virtual axis and a connecting rod by adopting an MC _ Power instruction and enabling a parameter ENABLE to take 1, and positioning the virtual axis to the corresponding position by adopting an MC _ MoveAbsolute instruction;
coupling the virtual axis and the connecting rod by using an MC _ CamIn motion control instruction, starting a cam curve camX of the virtual axis and the connecting rod, synchronizing the corresponding relation of the cam camX between the virtual axis and the connecting rod, and immediately starting synchronization when the parameter SyncProfileReference value takes 3;
when the valve is opened, the MC _ MoveAbsolute command is adopted to control the virtual axis so as to
Moves from 0 to S7 positionPlacing; when the valve is closed, the MC _ MoveAbsolute command is adopted to control the virtual axis so as to
Moves from the S7 to the 0 position;
after the task is completed, the MC _ Power instruction is adopted, the ENABLE parameter is 0, and the virtual shaft and the connecting rod are disabled.
TABLE 1 cam relationship Curve Table
Name (R)
|
S1
|
S2
|
S3
|
S4
|
S5
|
S6
|
S7
|
Virtual axis
|
0
|
Sx2
|
Sx3
|
Sx4
|
Sx5
|
Sx6
|
Sm
|
Valve core support plate shaft
|
0
|
Sy2
|
Sy3
|
Sy4
|
Sy5
|
Sy6
|
Sm |
The invention is not limited to the foregoing embodiments. The invention extends to any novel feature or any novel combination of features disclosed in this specification and any novel method or process steps or any novel combination of features disclosed.