KR102376322B1 - Pneumatic precision control means - Google Patents

Abstract

The present invention relates to a precision control means of a pneumatic actuator. More specifically, the precision control means (1) of a pneumatic actuator comprises: a position-based displacement precision control part (100) for controlling the position of a piston of a pneumatic actuator based on information measured in real time by a displacement sensor (S1); and a weight-based displacement precision control part (200) for controlling the position of the piston of the pneumatic actuator based on information measured in real time by a weight sensor (S2), thereby allowing pneumatic pressure supplied to the actuator to be controlled precisely. Accordingly, the present invention, as configured above, controls pneumatic pressure precisely, thereby enabling a precise and stable test through a test device using a pneumatic actuator.

Description

Pneumatic precision control means

The present invention relates to a means for precise control of a pneumatic actuator, and more particularly, to an algorithm capable of precisely controlling pneumatic pressure, through precise and stable feedback control for displacement and force, an actuator using pneumatic pressure to test equipment Even if applied, it relates to a pneumatic actuator precision control means that enables the same stable control as an incompressible fluid.

The reliability tester is a static and dynamic test equipment for basic material evaluation and product reliability evaluation in private sector, national research institutes, universities, and industries.

This is to improve the quality by securing basic data such as physical properties, lifespan, and limit of the product.

Currently, it is known that it is difficult to obtain precise and stable feedback control for force, speed, etc. due to the compressibility of air due to the compressibility of air. Most of the static and dynamic test equipment for reliability evaluation uses a tester using incompressible hydraulic pressure that can be controlled stably.

The hydraulic tester used in most institutions and laboratories uses hydraulic oil (oil). During repeated tests, water quality and water quality and Due to soil pollution, etc., it may become an environmental pollution problem.

For example, the hydraulic tester should replace 140 [liter] of hydraulic oil per 1 [year] based on the usage capacity of 10 [ton], and the hydraulic oil hose should be replaced at least 1 [times] every 3 [years].

However, in the case of a pneumatic tester, since a pneumatic line is used, the advantage of not using oil at all can be provided.

In addition, the use of hydraulic oil is in violation of domestic greenhouse gas policies and carbon emissions are continuously increasing. The government is also proposing to minimize the use of oil to reduce greenhouse gases as a policy.

Compared to the hydraulic tester, the pneumatic tester has the advantage that the introduction cost is very low, the related utilities are very cheap, and the utility installation is very simple, so that the entire system can be operated with only one pneumatic line.

In addition, maintenance and repair costs, in the case of a pneumatic tester, only the filter needs to be replaced, but in the case of a hydraulic tester, the filter, oil, hydraulic hose, etc. must be replaced after a certain period of time, so the maintenance and management cost is relatively expensive.

In summary, the hydraulic tester is easy for precise control, but the initial introduction, maintenance, and repair costs are high, space utilization is reduced because it occupies a lot of installation space, and environmental factors are poor due to the use of oil.

Therefore, the present invention provides a precision control algorithm that can supplement the compressibility of air, develops and applies a dedicated board optimized for pneumatic control, and uses a high-performance pneumatic reliability tester and eco-friendly air, cheap and popular reliability to manufacture test equipment.

That is, to precisely control the pneumatic actuator, it is difficult to obtain precise and stable feedback control for force, displacement, etc. due to the compressibility of air, so it was not easily applied to the test equipment. In order to solve and apply this problem, A method to overcome the limitations of temperature-dependent air density control and PID control must be resolved.

Accordingly, as a prior art related to a pneumatic actuator precision control means,

As shown in (a) of Figure 18, "Pneumatic actuator control system and control method thereof" of Korean Patent Application Laid-Open No. 10-2013-0091192 (hereinafter referred to as 'prior art 1'),

At least one pneumatic actuator operated by air pressure to generate mechanical power, a compression pump generating compressed air to be supplied to the pneumatic actuator and varying the capacity of the compressed air generated by an applied signal; A pneumatic supply unit that stores compressed air generated by It relates to a pneumatic actuator control system and a method for controlling the same, having a pump control unit that applies a signal to the compression pump to vary the capacity of the compressed air of the pump.

Another prior art,

As shown in (b) of FIG. 18, "Pneumatic actuator, pneumatic valve and pneumatic valve system using the same" of Republic of Korea Patent Publication No. 10-1991500 (hereinafter referred to as 'prior art 2'),

A drive cylinder part having a piston whose position is variable depending on the pressurization or release state of compressed air is installed therein, a drive shaft integrally coupled to the piston at one end passes through the inside, and a link installed therein according to the variable position of the piston A driving output unit configured to transmit a rotational force from the driving shaft to the output shaft through a member, and the other end of the driving shaft passing through the driving output unit are positioned, and a spring to have an elastic change state corresponding to the position variable state of the other end of the driving shaft It is installed therein and includes a spring cylinder part configured to provide an elastic restoring force of the spring corresponding to the pressurization or release state of the compressed air to the drive shaft and the piston, wherein the heating air is installed in a form surrounding the outside of the driving cylinder part It relates to a pneumatic actuator configured to provide a heating function while passing through an air line for heating, the inside of the drive output part, and the inside of the spring cylinder part in communication with each other.

As can be seen, the prior art 1 to the prior art 2 is a technology related to a pneumatic actuator and a system for controlling the same, and the present invention and the technical field are similar, but the technical characteristics are different.

That is, the means for controlling the pneumatic actuator to be provided in the present invention, the problem to be solved by the invention through this, and the effect exerted by solving the same are different.

Therefore, different from the precision control technology of pneumatic for the conventional pneumatic actuator including the prior art 1 and the prior art 2, the problem to be solved (object of the invention) of the present invention only, a solution for solving this ( components) and the effects exerted by solving them, we intend to seek its technical characteristics.

Republic of Korea Patent Publication No. 10-2013-0091192 (published on August 16, 2013) Republic of Korea Patent Publication No. 10-1991500 (Registered on June 14, 2019)

Accordingly, the present invention has been devised to solve the above-mentioned conventional problems,

An object of the present invention is to provide a control means capable of precisely controlling a pneumatic actuator.

That is, by precisely controlling the force and displacement control of the actuator using pneumatic pressure, the pneumatic actuator can be precisely controlled so that the actuator controlled by the incompressible fluid used in existing various test equipment can be replaced with an eco-friendly pneumatic actuator. The purpose of the present invention is to provide a control means.

The present invention for achieving the above object has been devised to achieve the problem to be solved,

In the pneumatic actuator precision control means,

Position-based displacement precision control unit for controlling the position of the piston of the pneumatic actuator based on the information measured in real time from the displacement sensor;

It consists of a; load-based displacement precision control unit that controls the position of the piston of the pneumatic actuator based on the information measured in real time from the load sensor.

It is characterized in that precise control of the pneumatic pressure supplied to the actuator is made.

At this time, the displacement sensor is

linear variable differential transformer (LVDT),

load sensor,

Consists of a load cell,

Position-based displacement precision control unit,

a feedback control module that primarily controls the position of the piston of the pneumatic actuator based on P-PI using the tracking error between the actual displacement and the input displacement measured in real time using a displacement sensor;

A feedforward control module with an auto gain tuning function that provides a weight to the signal itself input through the displacement sensor, multiplies the control output value, and adjusts the output; consists of,

It is characterized in that the feedback control module and the feedforward control module are activated at the same time to control the position of the piston of the pneumatic actuator.

On the other hand, prior to this, in this specification, the terms or words used in the claims of the patent registration should not be construed as being limited to conventional or dictionary meanings, and the inventor of the term in order to explain his invention in the best way. should be interpreted as meaning and concept consistent with the technical idea of the present invention based on the principle that can be appropriately defined.

Accordingly, the embodiments described in the present specification and the configurations shown in the drawings are only the most preferred embodiment of the present invention, and do not represent all of the technical spirit of the present invention. It should be understood that there may be equivalents and variations.

According to the present invention as described above in the above configuration and operation,

1. The pneumatic actuator can be controlled precisely.

That is, based on the information (signal) measured in real time from the displacement sensor and the load sensor, the actuator's force and displacement control using pneumatic pressure are precisely controlled, and the actuator controlled with incompressible fluid used in various existing test equipment, It can be replaced by an eco-friendly pneumatic actuator.

2. Therefore, the disadvantages of actuators using incompressible fluids (the cost for introduction, maintenance, and repair are expensive, and the inconvenience of maintenance and repair due to periodic hydraulic oil hose and oil management, oil change, etc.),

3. At the same time, since it uses pneumatic pressure, which is a feature of the present invention, it is possible to design, manufacture, and produce eco-friendly equipment (environmental policy as an eco-friendly system),

4. As a result, the cost and ease of management such as maintenance and repair are maximized.

5. Furthermore, by localizing the precision pneumatic servo actuator and linking it to export, it can contribute to the revitalization of the pneumatic actuator market in Korea and the development of technology.

6. Business areas can be expanded by increasing the marketability of smart factories.

That is, the main effect of the present invention is that even when a pneumatic actuator is applied to various test equipment, the same precise control as that of an actuator using an existing incompressible fluid is possible. It can be said that it is a very effective invention that can provide eco-friendly test equipment because it is used.

In addition, in response to environmental problems, the effect of replacing the test equipment using hydraulic pressure with the test equipment using pneumatic pressure,

With the effect of providing a precision pneumatic control algorithm,

Localization of pneumatic reliability test equipment and securing related source technology can be exerted in the pneumatic control field, which is dependent on foreign products.

1 shows a conceptual diagram for the present inventors, a pneumatic actuator precision control means.
Figure 2 shows the configuration of the present invention, a pneumatic actuator precision control means.
Figure 3 is a schematic representation of the flow chart for the control of the present inventor, a pneumatic actuator precision control means.
Figure 4 is a schematic representation of another flow chart for the control of the present invention, a pneumatic actuator precision control means.
5 is a flowchart schematically illustrating the P-PI control performed in the feedback control module among the components of the present inventor's pneumatic actuator precision control means.
6 is a flowchart schematically illustrating the FF control performed in the feedforward control module among the components of the present inventors, the pneumatic actuator precision control means.
7 is a block diagram of an algorithm for a position-based displacement precision control unit among the components of the present inventors, a pneumatic actuator precision control means, as an embodiment.
8 is a block diagram of an algorithm for a feedforward control module among the components of the present inventor's pneumatic actuator precision control means as an embodiment.
9 is a diagram schematically illustrating a method of applying the auto gain tuning function included in the feedforward control module among the components of the present inventor's precision control means for a pneumatic actuator.
10 is a block diagram of an algorithm for a load-based displacement precision control unit among components of the present inventor's precision control means for a pneumatic actuator as an embodiment.
11 shows an embodiment of a UI control module among the components of the present inventors, a pneumatic actuator precision control means.
12 shows the source code of the host PC element among the components of the present inventor's precision control means of a pneumatic actuator as an embodiment.
13 is an embodiment showing the source code for the panel control loop among the components of the present inventor's pneumatic actuator precision control means.
14 is an embodiment showing the source code for the automatic control loop among the components of the present inventor, the pneumatic actuator precision control means.
15 is an embodiment showing the source code for the data read loop among the components of the present inventor, the pneumatic actuator precision control means.
16 is an embodiment showing the source code for the data write loop among the components of the present inventor's pneumatic actuator precision control means.
17 shows an embodiment of a test equipment using a pneumatic actuator to which the present inventors, a pneumatic actuator precision control means are applied.
18 shows a representative view of the prior art for the present inventors, a pneumatic actuator precision control means.

Hereinafter, the function, configuration and operation of the pneumatic actuator precision control means 1 according to the present invention will be described in detail with reference to the accompanying drawings.

Figure 1, the present inventor, shows a conceptual diagram for the pneumatic actuator precision control means (1), Figure 2, the present inventor, shows a configuration diagram for the pneumatic actuator precision control means (1).

1 to 2, the present invention,

In the pneumatic actuator precision control means (1),

Position-based displacement precision control unit 100 for controlling the position of the piston of the pneumatic actuator based on the information measured in real time from the displacement sensor (S1);

The load-based displacement precision control unit 200 for controlling the position of the piston of the pneumatic actuator based on the information measured in real time from the load sensor S2;

It is characterized in that precise control of the pneumatic pressure supplied to the actuator is made.

That is, the present invention, for precise control of pneumatic pressure, based on PID control (proportional integral derivation control), P-PI control (proportional-proportional integral control) and FF (feed forward) control by applying, pneumatic actuator It is about a pneumatic actuator precision control means (1), which allows to precisely control the mechanical work of the piston of the

3 to 17, the present invention will be described in more detail,

The position-based displacement precision control unit 100 that precisely controls the position of the piston of the actuator by processing based on the information obtained through the displacement sensor S1,

It consists of a complex algorithm.

a feedback control module 110 that primarily controls the position of the piston of the pneumatic actuator based on P-PI using the tracking error between the actual displacement and the input displacement measured in real time using the displacement sensor S1;

Feedforward control module 120 including an auto gain tuning function that provides a weight to the signal itself input through the displacement sensor S1, multiplies the control output value, and adjusts the output; composed,

The feedback control module 110 and the feedforward control module 120 are activated at the same time to control the position of the piston of the pneumatic actuator.

At this time, the feed forward control module 120,

When the position of the piston of the pneumatic actuator is controlled only through the feedback control module 110, precise control at low speed and static state is possible, but when the position is input at high frequency, the delay of the proportional control valve of the piston As a result, it is configured to prevent precise control according to the frequency from being impossible.

That is, by analyzing the position signal of the piston measured in real time from the displacement sensor S1, the peak point and the valley point are detected, and then, the auto gain tuning that adjusts the gain value of the feed forward control module 120 (auto gain) tuning) function to adjust the gain value of the feedforward control module 120 until the actual amplitude reaches the target amplitude.

In addition, the feedback control module 110,

It is controlled based on P-PI control (Proportional-Proportional Integral Control),

a position-based displacement position control loop element 111 for deriving real-time measurement information transmitted from the displacement sensor S1, that is, a difference between an actual position and a target position, and providing an output result;

It is composed of;

The difference between the output result provided from the position-based displacement position control loop element 111, which is input to the position-based displacement speed control loop element 112, and the current speed of the piston of the pneumatic actuator is integrated into the input voltage of the actual proportional control valve. to be entered.

Such, the feedback control module 110,

It helps to reliably control a system that becomes unstable due to time delay (the system required to run the test equipment).

In addition, the auto gain tuning included in the feed forward control module 120 is,

By using the actual position information of the piston of the actual pneumatic actuator, the peak point and the valley point are detected,

After deriving the amplitude of the current wave (wave) from the detected peak and valley points, it is compared with the target amplitude.

At this time, if the current amplitude is lower than the target amplitude,

Increase the gain value of the feed forward control module 120,

In case of high

By reducing the gain value,

The difference between the target amplitude and the current amplitude is used to accumulate the difference between the two amplitudes, and then the principle of integral control is used.

On the other hand, the load-based displacement precision control unit 200,

a load-based displacement position control loop module 210 that determines the initial positions of the specimen and the piston, and changes an input value into a load value when the piston reaches the corresponding position;

a load-based displacement load control loop module 220 configured to change a feedback signal of information transmitted from the load-based displacement position control loop module 210 into a signal input from the load sensor S2 to start load control; consists of,

Based on the pressure information applied to the piston of the actuator, the load is precisely controlled.

That is, after the position control through the load-based displacement position control loop module 210 is completed, when the load control is changed to the load control by the load-based displacement load control loop module 220, the tracking error during position control is incorrect. ) to prevent input, the tracking error and gain values are initialized so that the accumulated error values do not affect the control performance.

At this time, the load-based displacement position control loop module 210,

It consists of the same algorithm as the position-based displacement precision control unit 100,

In addition, even after being changed to the load control mode by the load-based displacement load control loop module 220, in the same manner as the position-based displacement precision control unit 100, the P-PI-based feed forward control module 120 can be performed. .

On the other hand, by using the above-described position-based displacement precision control unit 100 and the load-based displacement precision control unit 200, fatigue test control unit 300 to facilitate various types of fatigue tests; composed,

It may be provided in the form of a platform UI.

At this time, the fatigue test control unit 300,

UI control module 310 configured to allow the tester to perform various types of fatigue tests;

A program source code module 320 designed to activate the UI control module 310;

UI control module 310,

a control menu element 310a for making an input for the fatigue test desired by the tester;

a gain tuning element 310b capable of adjusting the position-based displacement precision control unit 100 and the P-PI gain value of the load-based displacement precision control unit 200;

a crosshead control element 310c capable of controlling a crosshead;

The position-based displacement precision control unit 100 and the load-based displacement precision control unit 200, a controller internal monitoring element (310d) capable of monitoring;

a cycle setting element 310e capable of setting a target cycle while monitoring the number of current cycles in real time;

a record setting element (310f) for storing data by inputting test data storage path, name, date, and test person information;

Cycle analysis result monitoring element (310g) that can analyze the cycle and monitor the result;

a graph monitoring element (310h) capable of monitoring the generated wave in a graph during the fatigue test;

a dynamic data monitoring element 310i capable of monitoring dynamic data;

During the fatigue test, for the safety of the test equipment, the limit setting element 310j that can set the maximum and minimum displacement and load values;

Various fatigue tests are in progress, enabling real-time monitoring.

At this time, in the control menu element 310a,

The type of fatigue test (load, displacement), fatigue test amplitude, fatigue test frequency, piston speed, and valve power (ON/OFF) can be adjusted.

In addition, the gain tuning element (310b) is,

When adjusting the gain value, the position-based displacement precision control unit 100 and the load-based displacement precision control unit 200 are configured to be separately applied.

In addition, the UI control module 310,

After inputting a desired value in the control menu element 310a, the fatigue test automatic mode (A) to automatically start and complete the fatigue test through the start button;

Fatigue test manual mode (M), which allows the tester to directly conduct a fatigue test, and to monitor the current cycle through the manual test button; by selecting and controlling it,

It allows the tester to conduct various fatigue tests according to the situation and conditions.

The program source code module 320,

a host PC element 321 that includes functions related to the UI control module 310 and consists of 4 loops and manages the entire system;

an RT element 322 that transmits the control command input from the UI control module 310 and the host PC element 321 to the FPGA target element 323, and processes data necessary for the feedforward control module 120;

Using the control command received from the RT element 322 and each piece of information (information acquired in real time from the displacement sensor and load sensor), the movement of the actuator's piston is controlled through analog input and output and digital input and output. It consists of a FPGA target element 323;

Make sure that the actual test equipment can be operated in an optimal state.

At this time, the host PC element 321 is,

a panel control loop 321a that detects a value change and writes a value in the UI control module 310, and allows the input value to be applied;

When the test equipment is operated in the fatigue test automatic mode (A), the automatic control loop (321b) for allowing the fatigue test to proceed step by step while changing the value;

a data read loop 321c for processing data transmitted from the RT element 322;

Consists of; a data write loop 321d for transferring the data obtained from the UI control module 310 to the RT element 322;

Controls the entire system of test equipment.

A more detailed description of the role of each of the above components,

The panel control loop 321a,

Whenever each value of the UI control module 310 is changed, it serves to transmit the data to the RT element 322, and when the value is changed, a message is written in the queue and transmitted to the RT element 322 and confirms this message in the RT element 322, and controls the power supply (ON-OFF).

The automatic control loop 321b is,

When the test equipment is controlled in the fatigue test automatic mode (A), it is an operating loop, and the fatigue test automatic mode (A) is operated through 8 [steps].

For example,

After going through the process of 'Standby - Test information check - Test start - Control start - Initial point movement - Aging - Position (load) test - Control, test end', let the automatic fatigue test mode (A) operate.

In addition, the data read loop 321c,

After receiving the data (displacement sensor (S1), load sensor (S2)) transmitted from the RT element 322, and post-processing to detect peak points and valley points from the transmitted data, it is applied to the graph and each panel It is a loop to be used for control, and it also includes a role to store each collected data.

The data write loop 321d is,

It plays a role in transmitting information input from the UI control module 310 and processed through the host PC element 321 to the RT element 322, and the numerical value is transmitted by patterning the string into a cluster, and sending the text. to control the system.

In addition, the RT (real-time application) element 322 is,

It consists of 4 [pcs] loops,

a PC communication check loop 322a that checks the network connection state with the hospPC element 321 and blocks the operation of the loop when the connection is not smooth;

a PC communication write loop 322b for transmitting data to the host PC element 321;

a PC communication read loop 322c receiving data from the host PC element 321;

The FPGA data loop (322d) that performs the role of an auto gain tuner and acceleration/deceleration profiling in the loop for transmitting and receiving data with the FPGA target element 323;

The host PC element 321 and the FPGA target element 323 are connected to perform a control role.

When explaining the role of each configuration in more detail,

PC communication confirmation loop (322a),

As a loop for checking the wired communication state between the RT element 322 and the host PC element 321 , if the communication is normal, it is executed as it is, and if not, the control is terminated.

In addition, the PC communication write loop 322b,

The displacement sensor S1 and load sensor S2 information and control information processed by the RT element 322 are transmitted to the host PC element 321, but each data is patterned into a character string and transmitted.

PC communication read loop 322c,

This is a loop that cancels the patterning of the string information transmitted from the host PC element 321 and processes it with numerical values and Booleans so that the RT element 322 can utilize it. Each control information can be used appropriately by the RT element 322. It performs the function of inputting each numerical information so that

In addition, the FPGA data loop 322d,

It is a loop that directly exchanges data with the FPGA target element 323 and controls the operation of the piston of the actuator, including an acceleration/deceleration profiler and auto gain tuning. Element 323 performs the function of controlling the piston.

In addition, the FPGA target element 323 is,

a profiler 323a that generates a reference input corresponding to the amplitude, position, and frequency data received from the RT element 322 and generates a control command;

The position of the piston is controlled in accordance with the reference input generated from the profiler 323a, and the feedback control module 110 and the feed forward using the feedback signals of the displacement sensor S1 and the load sensor S2 are used. a controller 323b to be controlled through the control module 120;

an output unit 323c configured to input an output generated from the controller 323b as a voltage to the proportional control valve to control the position and force of the piston;

The displacement sensor (S1) and the PC communication unit (323d) to transmit the information obtained through the load sensor (S2) to the RT element 322 and the host PC element 321; Consists of,

The actual proportional control valve is controlled through the FPGA target element 323 .

Displacement sensor (S1) in the present invention,

With a linear variable differential transformer (LVDT),

The load sensor (S2) is,

A load cell may be applied.

As such, the precise control of pneumatic pressure through the present invention is

Regardless of the density of the air, the key is to be able to control a constant pneumatic pressure to the actuator at a speed of up to 10 [Hz], and this core technology can be applied to equipment using various pneumatic actuators.

Additionally, briefly describing the flowchart shown in FIGS. 3 to 6 ,

First, the flowchart of FIG. 3 (overall control flowchart of the present invention) is,

Set target speed and position,

Compare the target value with the actual value (speed, position) and calculate the error to increase or decrease the output,

Increase or decrease the output by calculating the speed error to reach the target value,

In the case of a dynamic target value (wave), increase or decrease the feed forward gain value by calculating the amplitude error,

It indicates that the final calculated output value is transmitted to the valve to be converted into the piston position or load value,

The flowchart of FIG. 4 (another overall control flowchart of the present invention) is,

Check the actual value (position, load),

Check the target value (position, load),

The error is calculated by comparing the target value and the actual value (position, load) (▶ Feedback control module 100)

Calculate the error by comparing the amplitude difference between the target value and the actual value (▶ Feedforward control module 120)

The output is increased or decreased by adding the calculated P-PI control value and the FF control value,

It represents that the final calculated output value is transmitted to the valve and converted into a piston position or load value,

The flowchart of FIG. 5 (P-PI control flowchart) is,

Calculate the position difference between the actual value and the target value to determine the proportional value,

Calculate the speed difference between the actual value and the target value to determine the speed proportional value,

Calculate the speed difference between the actual value and the target value to determine the speed integral value,

summing the determined position proportional value, velocity proportional value, and velocity integral value, indicating that the P-PI control value is determined,

The flowchart of FIG. 6 (FF control flowchart) is,

Calculate the amplitude of the actual value,

Calculate the amplitude of the target value,

It shows that the increase or decrease of the FF (feed forward) control value is determined by calculating the difference between the amplitude of the actual value and the amplitude of the target value.

As such, the present invention is a unique algorithm developed by applying P-PI control and FF control based on PID control, enabling precise and stable precise control of pneumatic pressure.

For reference, among the terms described in the present invention,

The position of the piston refers to the stroke degree of the piston moving in the cylinder,

'PID (proportional integral derivative) control' means,

It is a type of feedback control that maintains the reference voltage at the output of the system based on the error between the control variable and the reference input. It is a combination of proportional control, proportional integral control, and proportional differential control.

The proportional control (P) creates a control signal by multiplying the error signal between the reference signal and the current signal by an appropriate proportional constant gain.

In the proportional integral control (PI), an integral control that integrates an error signal to generate a control signal is used in parallel with the proportional control.

In the proportional differential control (PD), a differential control that differentiates an error signal to generate a control signal is used in parallel with the proportional control.

It is a control method used not only to measure the reaction of an automation system, but also to control the reaction. It is used to control temperature, pressure, flow rate, rotation speed, etc. can do.

In addition, PID (proportional integral derivative) control is,

Currently, the most used control method in industrial sites,

By detecting the current state of the plant (process value) with a sensor,

After calculating the difference from the user's desired set value,

By applying an appropriate controller output (manipulated value), the current value of the plant is matched to the target value by input operations according to the user's request, including proportion, integration, derivation, and three [types] operations. Take control of the method.

In addition, 'LVDT (linear variable differential transformer)' is,

In the form of an electrical transducer that measures the linear distance difference, 3 [pcs] solenoid coils are located in the form surrounding the tube, the middle coil is the main, and the other two are located outside the tube, and the cylinder-shaped magnetic core is located on the tube It provides the position value of the measurement target while moving along the center.

More simply, it is a transducer that converts mechanical displacement into an electrical signal and changes the magnetic flux induced from the primary coil to the secondary coil due to the movement of the core or armature, that is, the mutual inductance. Electrical output is generated in proportion to the displacement of the electrically separated and movable core,

In general, the coil is wound with a former (former), a core (core), a support bar for supporting the core, and consists of a case (case).

In addition, the 'load cell' is,

As a load sensor or force sensor,

A transducer for measuring a load or force, which can take out an output electrically.

A quantity that is easy to convert a load (force) into an electrical signal as a measurement object, for example, a primary conversion element that converts displacement or deformation, and an amount capable of outputting the primary conversion output (displacement or strain) as an electrical signal, such as For example, it is composed of a secondary conversion element that converts inductance change, capacitance change, resistance change, and the like.

That is, when a load (force) is applied, a deformation proportional to the stress occurs, and the electric resistance of the strain gauge changes according to the deformation. directly numerically.

In addition, 'FPGA (field programmable gate array)' is,

It is a semiconductor device that includes a designable logic device and a programmable internal circuit, and is a highly reliable programmable integrated circuit semiconductor.

All signals are processed in real time at the hardware level, synthesized and uploaded through a special hardware description language called HDL (hardware description language), so that logic operations and wiring inside the hardware are readjusted.

Currently, VHDL and a hardware description language called Verilog are mainly used.

The internal circuit of the processor is directly designed according to the program and directly executed in parallel, which has the advantage of being able to achieve much faster calculation speed than the CPU.

Designable logic elements can be programmed by replicating the functions of basic logic gates, such as AND, OR, XOR, NOT, and the functions of more complex decoders or combinations of computational functions, and most FPGAs contain simple flip-flops or It contains memory elements that are more complete memory blocks.

In addition, the programmable interline hierarchy allows the logical blocks of the FPGA to be interconnected, as required by the system designer, like a single-chip programmable breadboard.

Also, unlike other processors in which circuit changes are impossible, such as a CPU or GPU, a programmable processor can change the circuit according to the purpose.

In the present invention, a character written through '[]' means a unit of the corresponding number.

As described above, the present invention is not limited to the described embodiments, and it is apparent to those skilled in the art that various modifications and variations can be made without departing from the spirit and scope of the present invention. .

Therefore, since it can be implemented in various other forms without departing from the technical spirit or main characteristics, the embodiments of the present invention are merely examples in all respects and should not be construed as being limited, and may be implemented with various modifications. .

The present invention relates to a means for precise control of a pneumatic actuator, and to achieve precise control of pneumatic pressure, various industrial fields requiring precise control of actuators, in particular, fatigue test equipment for testing resistance to fatigue of materials, etc., replaced with pneumatic actuators Or, it can be applied to contribute to the promotion of equipment-related industries using it.

In addition, it can contribute to the advancement of the field of control systems that allow precise control of pneumatic pressure.

1: Pneumatic actuator precision control means
100: position-based displacement precision control unit 110: feedback control module
111: position-based displacement position control loop element
112: position-based displacement speed control loop element 120: feed forward control module
200: load-based displacement precision control unit
210: load-based displacement position control loop module
220: load-based displacement load control loop module
300: fatigue test control unit 310: UI control module
310a: control menu element 310b: gain tuning element
310c: crosshead control element 310d: controller internal monitoring element
310e: cycle setting element 310f: record setting element
310g: cycle analysis result monitoring element 310h: graph monitoring element
310i: dynamic data monitoring element 310j: limit setting element
320: program source code module 321: host PC element
321a: panel control loop 321b: automatic control loop
321c: data read loop 321d: data write loop
322: RT element 322a: PC communication confirmation loop
322b: PC communication write loop 322c: PC communication read loop
322d: FPGA data loop 323: FPGA target element
323a: Profiler 323b: Controller
323c: output unit 323d: PC communication unit
A: Fatigue test automatic mode M: Fatigue test manual mode
S1: displacement sensor S2: load sensor

Claims (3)

In the pneumatic actuator precision control means (1),
Position-based displacement precision control unit 100 for controlling the position of the piston of the pneumatic actuator based on the information measured in real time from the displacement sensor (S1);
The load-based displacement precision control unit 200 for controlling the position of the piston of the pneumatic actuator based on the information measured in real time from the load sensor S2;
characterized in that the precise control of the pneumatic pressure supplied to the actuator is made,
Pneumatic actuator precision control means. The method of claim 1,
Displacement sensor (S1),
linear variable differential transformer (LVDT),
The load sensor (S2),
characterized in that the load cell (load cell),
Pneumatic actuator precision control means. The method of claim 1,
Position-based displacement precision control unit 100,
a feedback control module 110 that primarily controls the position of the piston of the pneumatic actuator based on P-PI using the tracking error between the actual displacement and the input displacement measured in real time using the displacement sensor S1;
Feedforward control module 120 including an auto gain tuning function that provides a weight to the signal itself input through the displacement sensor S1, multiplies the control output value, and adjusts the output; consists of,
characterized in that the feedback control module 110 and the feedforward control module 120 are activated at the same time to control the position of the piston of the pneumatic actuator,
Pneumatic actuator precision control means.

Images