CA2837786A1 - Apparatus for precise pressure adjustment - Google Patents
Apparatus for precise pressure adjustment Download PDFInfo
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- CA2837786A1 CA2837786A1 CA2837786A CA2837786A CA2837786A1 CA 2837786 A1 CA2837786 A1 CA 2837786A1 CA 2837786 A CA2837786 A CA 2837786A CA 2837786 A CA2837786 A CA 2837786A CA 2837786 A1 CA2837786 A1 CA 2837786A1
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- pressure
- sensitive element
- processor
- elastic
- chamber
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B49/00—Control, e.g. of pump delivery, or pump pressure of, or safety measures for, machines, pumps, or pumping installations, not otherwise provided for, or of interest apart from, groups F04B1/00 - F04B47/00
- F04B49/08—Regulating by delivery pressure
Abstract
The present disclosure relates to an apparatus for precise pressure adjustment. The apparatus comprises: an elastic sensitive element, an elastic deformation converting apparatus, an electric stepper motor and driver, a rough pressure adjusting mechanism, a processor, a touch screen, an analog-to-digital converter, a pressure sensor (10) and a pressure-making chamber. The pressure-making chamber is connected to the chamber of the elastic sensitive element to make the pressure within the chambers equal. The pressure sensor senses the pressure within the pressure-making chamber and outputs an electric signal which is computed by the processor to obtain a current pressure value after being converted by the analog-to-digital converter. The processor compares a set pressure value inputted by a user though the touch screen with the current pressure value detected in real time to obtain an error value. By using a double closed-loop PI control algorithm, the processor first controls the rough pressure adjusting mechanism of the inner loop to rapidly perform rough adjustment, and then controls the direction of ration and the angle of the stepper motor of the outer loop to change the chamber volume of the elastic sensitive element through the elastic deformation conversion apparatus, and thus to achieve the function of precise pressure adjustment. The pressure adjustment control system in the present disclosure has high precision, short adjustment time, low cost, and wide application.
Description
APPARATUS FOR PRECISE PRESSURE ADJUSTMENT
TECHNICAL FIELD
The present disclosure relates to the field of industrial control, and in particular to an apparatus for precise pressure adjustment.
BACKGROUND
Pressure measurement plays important role in the industrial process control.
The performance of a pressure calibrating apparatus decides the calibration precision, efficiency and cost of a pressure instrument. Fully automatic pressure calibrators are replacing conventional piston pressure gauges gradually, and are widely applied in the field of electrical power, petroleum, petrochemical engineering, metallurgy, pharmacy or the like for it has many advantages such as high precision, wide application area, easy operation, functional integration, small size and so on.
Fully automatic pressure calibrators can be classified into gas pressure calibrators and liquid pressure calibrators depending on different instruments to be calibrated. The gas pressure calibrator takes non-corrosive gas as working medium, and is usually used to calibrate pressure instruments with relatively small measure range. Normal gas pressure calibrators control the gas input quantity and the gas output quantity of the pressure-making chamber by using the ON/OFF of an electromagnetic valve to thus achieve the purpose of adjusting pressure. The structure of a normal gas pressure calibrator is as shown in Fig. 1C. The liquid pressure calibrator takes non-conductive liquid such as transformer oil, sebacate, deionized water and so on as working medium, and is usually used to calibrate pressure instruments with relatively large measure range. Normal liquid pressure calibrators change the volume of the working medium in
TECHNICAL FIELD
The present disclosure relates to the field of industrial control, and in particular to an apparatus for precise pressure adjustment.
BACKGROUND
Pressure measurement plays important role in the industrial process control.
The performance of a pressure calibrating apparatus decides the calibration precision, efficiency and cost of a pressure instrument. Fully automatic pressure calibrators are replacing conventional piston pressure gauges gradually, and are widely applied in the field of electrical power, petroleum, petrochemical engineering, metallurgy, pharmacy or the like for it has many advantages such as high precision, wide application area, easy operation, functional integration, small size and so on.
Fully automatic pressure calibrators can be classified into gas pressure calibrators and liquid pressure calibrators depending on different instruments to be calibrated. The gas pressure calibrator takes non-corrosive gas as working medium, and is usually used to calibrate pressure instruments with relatively small measure range. Normal gas pressure calibrators control the gas input quantity and the gas output quantity of the pressure-making chamber by using the ON/OFF of an electromagnetic valve to thus achieve the purpose of adjusting pressure. The structure of a normal gas pressure calibrator is as shown in Fig. 1C. The liquid pressure calibrator takes non-conductive liquid such as transformer oil, sebacate, deionized water and so on as working medium, and is usually used to calibrate pressure instruments with relatively large measure range. Normal liquid pressure calibrators change the volume of the working medium in
- 2 -the cylinder by using an electric motor or gas to push the piston to move in the cylinder, thus achieving the purpose of adjusting pressure, as shown in Fig. 1A and Fig.
1B.
Currently, the pressure-making precision of a fully automatic pressure calibrator is mainly subject to the performance of the pressure sensor and the actuating mechanism.
The performance of the actuating mechanism is determined by the fabrication precision, the consistency of elements and the cost of fabrication and purchase of the actuating mechanism.
In a conventional gas pressure system, the response time of the electromagnetic valve is usually in the range of 10-30 ms, or in the range of 5-10 ms for better ones.
Moreover, its price is very high, and the consistency cannot be assured. The amount of gas flow during the smallest switching interval of the electromagnetic valve usually decides the precision of the pressure adjustment. Reducing the amount of gas flow during the smallest switching interval by reducing the pressure difference between the two sides of the electromagnetic valve would usually increase the complexity of the system and improve the cost. Though reducing the path diameter of the electromagnetic valve can reduce the amount of gas flow during the smallest switching interval, it increases the adjustment time at the same time. Increasing the volume of the pressure-making chamber would increase the vibration of the gas due to the bulk-cavity effect and would thus increase the adjustment time. In a conventional liquid pressure system, for a pressure-making system by the electric motor pushing the piston, the fabrication precision of the transmission screw would influence the shift of the piston in a unit step of the electric motor, and thus influence the resolution of the pressure adjustment. High precision screws are usually very expensive, and not easy to be fabricated. The electric motor adapted thereto also needs to be a stepper motor or a servo motor with high precision, stable torque, and low heating, which further
1B.
Currently, the pressure-making precision of a fully automatic pressure calibrator is mainly subject to the performance of the pressure sensor and the actuating mechanism.
The performance of the actuating mechanism is determined by the fabrication precision, the consistency of elements and the cost of fabrication and purchase of the actuating mechanism.
In a conventional gas pressure system, the response time of the electromagnetic valve is usually in the range of 10-30 ms, or in the range of 5-10 ms for better ones.
Moreover, its price is very high, and the consistency cannot be assured. The amount of gas flow during the smallest switching interval of the electromagnetic valve usually decides the precision of the pressure adjustment. Reducing the amount of gas flow during the smallest switching interval by reducing the pressure difference between the two sides of the electromagnetic valve would usually increase the complexity of the system and improve the cost. Though reducing the path diameter of the electromagnetic valve can reduce the amount of gas flow during the smallest switching interval, it increases the adjustment time at the same time. Increasing the volume of the pressure-making chamber would increase the vibration of the gas due to the bulk-cavity effect and would thus increase the adjustment time. In a conventional liquid pressure system, for a pressure-making system by the electric motor pushing the piston, the fabrication precision of the transmission screw would influence the shift of the piston in a unit step of the electric motor, and thus influence the resolution of the pressure adjustment. High precision screws are usually very expensive, and not easy to be fabricated. The electric motor adapted thereto also needs to be a stepper motor or a servo motor with high precision, stable torque, and low heating, which further
- 3 -improves the cost of the system. For a pressure-making system with gas pushing liquid, the same difficulties as the gas pressure system exist.
SUMMARY OF THE DISCLOSURE
In view of the above, the object of the present disclosure is to provide a control system in which precise pressure adjustment is performed with the deformation of an elastic sensitive element to reduce the performance requirement on a conventional adjusting mechanism, simplify the system structure, and improve the precision of the pressure-In order to achieve the above object, the present disclosure adopts the following features.
pressure adjustment, comprising: an actuating mechanism (1) comprising an elastic sensitive element (3), an elastic deformation converting apparatus (4), a electric stepper motor and driver (5), a rough pressure adjusting mechanism (6) and a pressure-making chamber (11), the pressure-making chamber (11) being connected to
SUMMARY OF THE DISCLOSURE
In view of the above, the object of the present disclosure is to provide a control system in which precise pressure adjustment is performed with the deformation of an elastic sensitive element to reduce the performance requirement on a conventional adjusting mechanism, simplify the system structure, and improve the precision of the pressure-In order to achieve the above object, the present disclosure adopts the following features.
pressure adjustment, comprising: an actuating mechanism (1) comprising an elastic sensitive element (3), an elastic deformation converting apparatus (4), a electric stepper motor and driver (5), a rough pressure adjusting mechanism (6) and a pressure-making chamber (11), the pressure-making chamber (11) being connected to
- 4 -control on the actuating mechanism (1) to adjust the pressure within the pressure-making chamber (11) by comparing the error value with a set error threshold.
In accordance with the apparatus for precise pressure adjustment in a preferable embodiment of the present disclosure, the double closed-loop control further comprises:
when the error value is outside the set error threshold range, the processor (7) initiating an inner loop to control the rough pressure adjusting mechanism (6) to perform rough pressure adjustment rapidly; when the error value is within the set error threshold range, the processor (7) initiating an outer loop to control the rotation direction and the angle of the electric stepper motor and driver (5) such that the elastic deformation converting apparatus (4) changes the chamber volume of the elastic sensitive element (3) to adjust the pressure within the pressure-making chamber (11).
In accordance with the apparatus for precise pressure adjustment in a preferable embodiment of the present disclosure, when the error value is within the set error threshold range, the processor (7) initiating an outer loop to control the rotation direction and the angle of the electric stepper motor and driver (5) such that the elastic deformation converting apparatus (4) changes the chamber volume of the elastic sensitive element (3) to adjust the pressure within the pressure-making chamber (11) further comprises: when the pressure within the pressure-making chamber (11) needs to be raised, reducing the chamber volume of the elastic sensitive element (3); when the pressure within the pressure-making chamber (11) needs to be reduced, increasing the chamber volume of the elastic sensitive element (3).
In accordance with the apparatus for precise pressure adjustment in a preferable embodiment of the present disclosure, the elastic sensitive element (3) is a spring tub, a bellows or an elastic diaphragm.
In accordance with the apparatus for precise pressure adjustment in a preferable embodiment of the present disclosure, the double closed-loop control further comprises:
when the error value is outside the set error threshold range, the processor (7) initiating an inner loop to control the rough pressure adjusting mechanism (6) to perform rough pressure adjustment rapidly; when the error value is within the set error threshold range, the processor (7) initiating an outer loop to control the rotation direction and the angle of the electric stepper motor and driver (5) such that the elastic deformation converting apparatus (4) changes the chamber volume of the elastic sensitive element (3) to adjust the pressure within the pressure-making chamber (11).
In accordance with the apparatus for precise pressure adjustment in a preferable embodiment of the present disclosure, when the error value is within the set error threshold range, the processor (7) initiating an outer loop to control the rotation direction and the angle of the electric stepper motor and driver (5) such that the elastic deformation converting apparatus (4) changes the chamber volume of the elastic sensitive element (3) to adjust the pressure within the pressure-making chamber (11) further comprises: when the pressure within the pressure-making chamber (11) needs to be raised, reducing the chamber volume of the elastic sensitive element (3); when the pressure within the pressure-making chamber (11) needs to be reduced, increasing the chamber volume of the elastic sensitive element (3).
In accordance with the apparatus for precise pressure adjustment in a preferable embodiment of the present disclosure, the elastic sensitive element (3) is a spring tub, a bellows or an elastic diaphragm.
- 5 -In accordance with the apparatus for precise pressure adjustment in a preferable embodiment of the present disclosure, the pressure sensor (10) is a silicon piezoresistive pressure sensor or a silicon resonant pressure sensor.
In accordance with the apparatus for precise pressure adjustment in a preferable embodiment of the present disclosure, the analog-to-digital converter (9) is a Z-.6, typed analog-to-digital converter (9).
Compared with the prior art, the present disclosure has the following advantages and positive benefits due to the adoption of the above features.
The advantages of the present disclosure over the prior art are as follows.
(1) In the present disclosure, an inner-loop conventional pressure adjusting mechanism and an outer-loop elastic sensitive element mechanism are used to cooperate with each other. A stable pressure adjustment with high precision is achieved by changing the volume of the chamber of the elastic sensitive element. The present disclosure can apply to both the gas pressure system and the liquid pressure system.
(2) The present disclosure adopts a double closed-loop PI control method to make the rough pressure adjusting mechanism and the elastic sensitive element mechanism cooperate with each other so as to reach a stable set pressure rapidly. That is, when the error value is outside the set error threshold range, the rough pressure adjusting mechanism is initiated to rapidly adjust the pressure; when the error value is within the set error threshold range, the elastic sensitive element mechanism is initiated to adjust the pressure precisely. In both inner and outer PI
components, when the error value is outside respective set error threshold ranges, the adjustment mechanism adjusts the pressure with the highest adjustment speed;
and once the error value falls into the set error threshold range, a parameter self-
In accordance with the apparatus for precise pressure adjustment in a preferable embodiment of the present disclosure, the analog-to-digital converter (9) is a Z-.6, typed analog-to-digital converter (9).
Compared with the prior art, the present disclosure has the following advantages and positive benefits due to the adoption of the above features.
The advantages of the present disclosure over the prior art are as follows.
(1) In the present disclosure, an inner-loop conventional pressure adjusting mechanism and an outer-loop elastic sensitive element mechanism are used to cooperate with each other. A stable pressure adjustment with high precision is achieved by changing the volume of the chamber of the elastic sensitive element. The present disclosure can apply to both the gas pressure system and the liquid pressure system.
(2) The present disclosure adopts a double closed-loop PI control method to make the rough pressure adjusting mechanism and the elastic sensitive element mechanism cooperate with each other so as to reach a stable set pressure rapidly. That is, when the error value is outside the set error threshold range, the rough pressure adjusting mechanism is initiated to rapidly adjust the pressure; when the error value is within the set error threshold range, the elastic sensitive element mechanism is initiated to adjust the pressure precisely. In both inner and outer PI
components, when the error value is outside respective set error threshold ranges, the adjustment mechanism adjusts the pressure with the highest adjustment speed;
and once the error value falls into the set error threshold range, a parameter self-
- 6 -regulating PI control method is used to adjust the pressure. In order to improve the performance of the closed-loop control system, shorten the response time, and make the pressure-making system to reach the stable set pressure as soon as possible, in both inner and outer loops, the coefficients of respective components of the PI controller are regulated appropriately according to the error value.
Compared with the ordinary PI control method, it shortens the response time dramatically and improves the capability of disturbance resistance.
(3) The structure according to the present disclosure is simple and the design of the elastic sensitive element mechanism is flexible.
The conventional pressure adjustment mechanism adapted thereto needs relatively low fabrication precision and consistency. The cost is also reduced, and there is a promising potential market.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1A is a diagram of a liquid pressure adjusting mechanism with an electric motor pushing a piston.
Fig. 1B is a diagram of a liquid pressure adjusting mechanism with gas pushing a piston.
Fig. 10 is a diagram of a gas pressure adjusting mechanism with an electromagnetic valve controlling the gas input quantity and the gas output quantity.
Fig. 2 is a structural block diagram of an apparatus for precise pressure adjustment provided in an embodiment of the present disclosure.
Fig. 3A is a schematic diagram of an elastic sensitive element and elastic deformation conversion apparatus thereof in an embodiment of the present disclosure.
Fig. 3B is a schematic diagram of an elastic sensitive element and elastic deformation conversion apparatus thereof in another embodiment of the present disclosure.
Compared with the ordinary PI control method, it shortens the response time dramatically and improves the capability of disturbance resistance.
(3) The structure according to the present disclosure is simple and the design of the elastic sensitive element mechanism is flexible.
The conventional pressure adjustment mechanism adapted thereto needs relatively low fabrication precision and consistency. The cost is also reduced, and there is a promising potential market.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1A is a diagram of a liquid pressure adjusting mechanism with an electric motor pushing a piston.
Fig. 1B is a diagram of a liquid pressure adjusting mechanism with gas pushing a piston.
Fig. 10 is a diagram of a gas pressure adjusting mechanism with an electromagnetic valve controlling the gas input quantity and the gas output quantity.
Fig. 2 is a structural block diagram of an apparatus for precise pressure adjustment provided in an embodiment of the present disclosure.
Fig. 3A is a schematic diagram of an elastic sensitive element and elastic deformation conversion apparatus thereof in an embodiment of the present disclosure.
Fig. 3B is a schematic diagram of an elastic sensitive element and elastic deformation conversion apparatus thereof in another embodiment of the present disclosure.
- 7 -Fig. 4 is a flowchart of the processor implementation in an embodiment of the present disclosure.
Fig. 5 is a principle schematic diagram for the processor using parameter self-regulating PI control.
DETAILED DESCRIPTION
In the following, the technical solutions of the present disclosure will be further described in detail in connection with drawings and embodiments.
The embodiments of the present disclosure will be further described in detail in the following in connection with the drawings.
As shown in Fig. 2, embodiments of the present disclosure provide an apparatus for precise pressure adjustment. As shown in the figure, the apparatus comprises:
an actuating mechanism (1) comprising an elastic sensitive element (3), an elastic deformation converting apparatus (4), a electric stepper motor and driver (5), a rough pressure adjusting mechanism (6) and a pressure-making chamber (11), the pressure-making chamber (11) being connected to the chamber of the elastic sensitive element (3) to make the pressure within the chambers equal; a control mechanism (2) comprising a processor (7), a touch screen (8), a analog-to-digital converter (9) and a pressure sensor (10), wherein the pressure sensor (10) senses the pressure within the pressure-making chamber (11) and outputs an electric signal which is computed by the processor (7) to obtain a current pressure value after being converted by the analog-to-digital converter (9), and the processor (7) compares a set pressure value inputted by a user though the touch screen (8) with the current pressure value to obtain an error value, and performs a double closed-loop control on the actuating mechanism (1) to
Fig. 5 is a principle schematic diagram for the processor using parameter self-regulating PI control.
DETAILED DESCRIPTION
In the following, the technical solutions of the present disclosure will be further described in detail in connection with drawings and embodiments.
The embodiments of the present disclosure will be further described in detail in the following in connection with the drawings.
As shown in Fig. 2, embodiments of the present disclosure provide an apparatus for precise pressure adjustment. As shown in the figure, the apparatus comprises:
an actuating mechanism (1) comprising an elastic sensitive element (3), an elastic deformation converting apparatus (4), a electric stepper motor and driver (5), a rough pressure adjusting mechanism (6) and a pressure-making chamber (11), the pressure-making chamber (11) being connected to the chamber of the elastic sensitive element (3) to make the pressure within the chambers equal; a control mechanism (2) comprising a processor (7), a touch screen (8), a analog-to-digital converter (9) and a pressure sensor (10), wherein the pressure sensor (10) senses the pressure within the pressure-making chamber (11) and outputs an electric signal which is computed by the processor (7) to obtain a current pressure value after being converted by the analog-to-digital converter (9), and the processor (7) compares a set pressure value inputted by a user though the touch screen (8) with the current pressure value to obtain an error value, and performs a double closed-loop control on the actuating mechanism (1) to
- 8 -adjust the pressure within the pressure-making chamber (11) by comparing the error value with a set error threshold.
More specifically, provided by the embodiments of the present disclosure is an apparatus for performing precise pressure adjustment with the deformation of an elastic sensitive element, wherein the elastic sensitive element 3, the elastic deformation conversion apparatus 4, the electric stepper motor and driver 5 constitute a core actuating mechanism for precise pressure adjustment. As shown in Fig. 3A, the driver controls the rotation direction and the torque of the electric stepper motor 5 to change the deformation of the spring tube by the deformation conversion apparatus, and thus to change the volume of the spring tube chamber and the working medium. When the motor shaft rotates clockwise, the chamber is decreased and the pressure increases.
When the motor shaft rotates counterclockwise, the chamber is increased and the pressure decreases. As shown in Fig. 3B, the driver controls the electric stepper motor 5 to push or pull a movable rod member through a screw, and thus to change the volume of the bellows chamber and the working medium. When the movable rod member is pushed to move toward the left, the bellows is compressed, the chamber is decreased, and the pressure increases. When the movable rod member is pushed to move toward the right, the bellows is stretched, the chamber is increased, and the pressure decreases. With the double closed-loop PI control method, the control mechanism (or referred to as control circuit) consisted of the pressure sensor 10, the analog-to-digital converter 9 and the processor 7 can control the rough pressure adjusting mechanism 6 and, at the same time, control the driver to actuate the electric stepper motor 5 to change the deformation of the elastic sensitive element 3, which make the rough pressure adjusting mechanism 6 and the elastic sensitive element 3 cooperate with each other to achieve a stable and fast pressure adjustment.
More specifically, provided by the embodiments of the present disclosure is an apparatus for performing precise pressure adjustment with the deformation of an elastic sensitive element, wherein the elastic sensitive element 3, the elastic deformation conversion apparatus 4, the electric stepper motor and driver 5 constitute a core actuating mechanism for precise pressure adjustment. As shown in Fig. 3A, the driver controls the rotation direction and the torque of the electric stepper motor 5 to change the deformation of the spring tube by the deformation conversion apparatus, and thus to change the volume of the spring tube chamber and the working medium. When the motor shaft rotates clockwise, the chamber is decreased and the pressure increases.
When the motor shaft rotates counterclockwise, the chamber is increased and the pressure decreases. As shown in Fig. 3B, the driver controls the electric stepper motor 5 to push or pull a movable rod member through a screw, and thus to change the volume of the bellows chamber and the working medium. When the movable rod member is pushed to move toward the left, the bellows is compressed, the chamber is decreased, and the pressure increases. When the movable rod member is pushed to move toward the right, the bellows is stretched, the chamber is increased, and the pressure decreases. With the double closed-loop PI control method, the control mechanism (or referred to as control circuit) consisted of the pressure sensor 10, the analog-to-digital converter 9 and the processor 7 can control the rough pressure adjusting mechanism 6 and, at the same time, control the driver to actuate the electric stepper motor 5 to change the deformation of the elastic sensitive element 3, which make the rough pressure adjusting mechanism 6 and the elastic sensitive element 3 cooperate with each other to achieve a stable and fast pressure adjustment.
- 9 -The elastic sensitive element in the present disclosure can be chosen as the spring tube shown in Fig. 3A, the bellows shown in Fig. 3B, an elastic membrane, or the like, which can work with the aid of a simple elastic deformation conversion apparatus. The processor 7 can control the deformation of the elastic sensitive element trough the electric stepper motor and driver. The volume of the chamber of the elastic sensitive element should be suitable for the total volume of the entire pressure-making circuit. If it is too small, the pressure adjusting range would be small. If it is too large, it cannot function for precise pressure adjustment. At the same time, the pressure adjusting resolution of the rough pressure adjusting mechanism also needs to be considered.
As shown in Fig. 4, the processor 7 in the present disclosure receives a set pressure value set by a user through the touch screen 8. The pressure sensor 10 senses the pressure value within the pressure-making chamber 11. The pressure value is collected by the analog-to-digital converter 9 and then computed by the processor 7 to obtain the current pressure value.
The processor 7 compares the set pressure value with the current pressure value to obtain an error value. When the error value is outside the set error threshold range, the processor 7 initiates the rough pressure adjusting mechanism 6 of the inner loop through a parameter self-regulating PI control method to adjust the pressure rapidly while the mechanism of the elastic sensitive element 3 of the outer loop does not work.
When the error value is within the set error threshold range, the processor 7 initiates the mechanism of the elastic sensitive element 3 of the outer loop to perform precise pressure adjustment through a parameter self-regulating PI control method while the rough pressure adjusting mechanism 6 of the inner loop does not work. The above closed-loop control method is performed cyclically until the stable set pressure is achieved.
As shown in Fig. 4, the processor 7 in the present disclosure receives a set pressure value set by a user through the touch screen 8. The pressure sensor 10 senses the pressure value within the pressure-making chamber 11. The pressure value is collected by the analog-to-digital converter 9 and then computed by the processor 7 to obtain the current pressure value.
The processor 7 compares the set pressure value with the current pressure value to obtain an error value. When the error value is outside the set error threshold range, the processor 7 initiates the rough pressure adjusting mechanism 6 of the inner loop through a parameter self-regulating PI control method to adjust the pressure rapidly while the mechanism of the elastic sensitive element 3 of the outer loop does not work.
When the error value is within the set error threshold range, the processor 7 initiates the mechanism of the elastic sensitive element 3 of the outer loop to perform precise pressure adjustment through a parameter self-regulating PI control method while the rough pressure adjusting mechanism 6 of the inner loop does not work. The above closed-loop control method is performed cyclically until the stable set pressure is achieved.
- 10 -As shown in Fig. 5, in the embodiments of the present disclosure, the processor 7 controls the pressure through a double closed-loop parameter self-regulating PI control method. The processor adjusts the proportion coefficient Kp and the integration coefficient Ki of the PI component according to the error value through the PI
control algorithm. The output of Kp control is proportional to the input error value and is used for fast response. The output of Ki control is proportional to the integral of the error value, and is used to eliminate the static error. That is, when the absolute error value is relatively large (in the present embodiment, larger than 20% of the input value of the inner or outer loop), Kp takes a relatively large value (in the present embodiment, 25), Ki takes 0, and at this point the rough pressure adjusting mechanism 6 or the mechanism of the elastic sensitive element 3 adjusts the pressure rapidly or deforms rapidly to make the absolute error value decrease as soon as possible. When the absolute error value is medium (in the present embodiment, larger than 10% and smaller than 20% of the input value of the inner or outer loop), Kp takes a medium value (in the present embodiment, 20), Ki takes a relatively small value (in the present embodiment, 0.0005), and at this point the rough pressure adjusting mechanism 6 or the mechanism of the elastic sensitive element 3 reduces the speed of adjusting the pressure or deforming to avoid over-adjusting. When the absolute error value decreases further (in the present embodiment, larger than 5% and smaller than 10% of the input value of the inner or outer loop), Kp takes a relatively small value (in the present embodiment, 5), Ki takes a medium value (in the present embodiment, 0.01), and at this point, the rough pressure adjusting mechanism 6 or the deformation of the elastic sensitive element 3 is adjusted slowly. When the absolute error value reaches the smallest (in the present embodiment, smaller than 5% of the input value of the outer loop), Kp takes a medium value (in the present embodiment, 10), Ki takes the maximum value (in the present embodiment, 0.02), and at this point, mainly the deformation of the elastic sensitive element 3 is adjusted finely to achieve the function of precise pressure adjustment. The above process makes both the inner and outer
control algorithm. The output of Kp control is proportional to the input error value and is used for fast response. The output of Ki control is proportional to the integral of the error value, and is used to eliminate the static error. That is, when the absolute error value is relatively large (in the present embodiment, larger than 20% of the input value of the inner or outer loop), Kp takes a relatively large value (in the present embodiment, 25), Ki takes 0, and at this point the rough pressure adjusting mechanism 6 or the mechanism of the elastic sensitive element 3 adjusts the pressure rapidly or deforms rapidly to make the absolute error value decrease as soon as possible. When the absolute error value is medium (in the present embodiment, larger than 10% and smaller than 20% of the input value of the inner or outer loop), Kp takes a medium value (in the present embodiment, 20), Ki takes a relatively small value (in the present embodiment, 0.0005), and at this point the rough pressure adjusting mechanism 6 or the mechanism of the elastic sensitive element 3 reduces the speed of adjusting the pressure or deforming to avoid over-adjusting. When the absolute error value decreases further (in the present embodiment, larger than 5% and smaller than 10% of the input value of the inner or outer loop), Kp takes a relatively small value (in the present embodiment, 5), Ki takes a medium value (in the present embodiment, 0.01), and at this point, the rough pressure adjusting mechanism 6 or the deformation of the elastic sensitive element 3 is adjusted slowly. When the absolute error value reaches the smallest (in the present embodiment, smaller than 5% of the input value of the outer loop), Kp takes a medium value (in the present embodiment, 10), Ki takes the maximum value (in the present embodiment, 0.02), and at this point, mainly the deformation of the elastic sensitive element 3 is adjusted finely to achieve the function of precise pressure adjustment. The above process makes both the inner and outer
- 11 -loops respond rapidly so that the double closed-loop system can reach the stable set pressure faster. The method responds faster than the conventional PI control method.
The pressure sensor 10 in the embodiments of the present disclosure can adopt commonly used silicon piezoresistive pressure sensors or silicon resonant pressure sensors, depending on the requirement of precision and performance. The processor 7 can be implemented by commonly used digital signal processors, ARM or the like, for example, TMS320F28335 or the like.
In a possible implementation, considering that the electric signal output by the pressure sensor 10 usually is a weak signal in the level of uA or mV, and the pressure signal within the pressure-making chamber 11 cannot change rapidly within a short time, it is proposed to use a high resolution, high signal-to-noise ratio, high integration Z-A typed analog-to-digital converter 9, for example, AD7714.
The set pressure input by a user can be implemented by a touch screen or a simple button or digital tube.
The above specific implementation provides a further detailed description of the object, the technical solutions and the technical benefits of the present disclosure.
It is understood that the above description is only specific embodiments of the present disclosure and is not intended to limit the protection scope of the present disclosure.
Any modification, equivalent replacement, enhancement or the like within the principle of the present disclosure should all be contained within the protection scope of the present disclosure.
The pressure sensor 10 in the embodiments of the present disclosure can adopt commonly used silicon piezoresistive pressure sensors or silicon resonant pressure sensors, depending on the requirement of precision and performance. The processor 7 can be implemented by commonly used digital signal processors, ARM or the like, for example, TMS320F28335 or the like.
In a possible implementation, considering that the electric signal output by the pressure sensor 10 usually is a weak signal in the level of uA or mV, and the pressure signal within the pressure-making chamber 11 cannot change rapidly within a short time, it is proposed to use a high resolution, high signal-to-noise ratio, high integration Z-A typed analog-to-digital converter 9, for example, AD7714.
The set pressure input by a user can be implemented by a touch screen or a simple button or digital tube.
The above specific implementation provides a further detailed description of the object, the technical solutions and the technical benefits of the present disclosure.
It is understood that the above description is only specific embodiments of the present disclosure and is not intended to limit the protection scope of the present disclosure.
Any modification, equivalent replacement, enhancement or the like within the principle of the present disclosure should all be contained within the protection scope of the present disclosure.
Claims (6)
1. An apparatus for precise pressure adjustment, characterized by comprising:
an actuating mechanism (1) comprising an elastic sensitive element (3), an elastic deformation converting apparatus (4), an electric stepper motor and driver (5), a rough pressure adjusting mechanism (6) and a pressure-making chamber (11), the pressure-making chamber (11) being connected to the chamber of the elastic sensitive element (3) to make the pressure within the chambers equal;
a control mechanism (2) comprising a processor (7), a touch screen (8), a analog-to-digital converter (9) and a pressure sensor (10), wherein the pressure sensor (10) senses the pressure within the pressure-making chamber (11) and outputs an electric signal which is computed by the processor (7) to obtain a current pressure value after being converted by the analog-to-digital converter (9), and the processor (7) compares a set pressure value inputted by a user though the touch screen (8) with the current pressure value to obtain an error value, and performs a double closed-loop control on the actuating mechanism (1) to adjust the pressure within the pressure-making chamber (11) by comparing the error value with a set error threshold.
an actuating mechanism (1) comprising an elastic sensitive element (3), an elastic deformation converting apparatus (4), an electric stepper motor and driver (5), a rough pressure adjusting mechanism (6) and a pressure-making chamber (11), the pressure-making chamber (11) being connected to the chamber of the elastic sensitive element (3) to make the pressure within the chambers equal;
a control mechanism (2) comprising a processor (7), a touch screen (8), a analog-to-digital converter (9) and a pressure sensor (10), wherein the pressure sensor (10) senses the pressure within the pressure-making chamber (11) and outputs an electric signal which is computed by the processor (7) to obtain a current pressure value after being converted by the analog-to-digital converter (9), and the processor (7) compares a set pressure value inputted by a user though the touch screen (8) with the current pressure value to obtain an error value, and performs a double closed-loop control on the actuating mechanism (1) to adjust the pressure within the pressure-making chamber (11) by comparing the error value with a set error threshold.
2. The apparatus for precise pressure adjustment according to claim 1, characterized in that the double closed-loop control further comprises:
when the error value is outside the set threshold range, the processor (7) initiating an inner loop to control the rough pressure adjusting mechanism (6) to perform rough pressure adjustment rapidly;
when the error value is within the error threshold range, the processor (7) initiating an outer loop to control the rotation direction and the angle of the electric stepper motor and driver (5) such that the elastic deformation converting apparatus (4) changes the chamber volume of the elastic sensitive element (3) to adjust the pressure within the pressure-making chamber (11).
when the error value is outside the set threshold range, the processor (7) initiating an inner loop to control the rough pressure adjusting mechanism (6) to perform rough pressure adjustment rapidly;
when the error value is within the error threshold range, the processor (7) initiating an outer loop to control the rotation direction and the angle of the electric stepper motor and driver (5) such that the elastic deformation converting apparatus (4) changes the chamber volume of the elastic sensitive element (3) to adjust the pressure within the pressure-making chamber (11).
3. The apparatus for precise pressure adjustment according to claim 2, characterized in that said when the error value is within the error threshold range, the processor (7) initiating an outer loop to control the rotation direction and the angle of the electric stepper motor and driver (5) such that the elastic deformation converting apparatus (4) changes the chamber volume of the elastic sensitive element (3) to adjust the pressure within the pressure-making chamber (11) further comprises:
when the pressure within the pressure-making chamber (11) needs to be raised, reducing the chamber volume of the elastic sensitive element (3), when the pressure within the pressure-making chamber (11) needs to be reduced, increasing the chamber volume of the elastic sensitive element (3).
when the pressure within the pressure-making chamber (11) needs to be raised, reducing the chamber volume of the elastic sensitive element (3), when the pressure within the pressure-making chamber (11) needs to be reduced, increasing the chamber volume of the elastic sensitive element (3).
4. The apparatus for precise pressure adjustment according to claim 1, characterized in that the elastic sensitive element (3) is a spring tub, a bellows or an elastic diaphragm.
The apparatus for precise pressure adjustment according to any one of claims 1-4, characterized in that the pressure sensor (10) is a silicon piezoresistive pressure sensor or a silicon resonant pressure sensor
6. The apparatus for precise pressure adjustment according to any one of claims 1-5, characterized in that the analog-to-digital converter (9) is a.SIGMA.-.delta. typed analog-to-digital converter (9).
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201210586305.6A CN103092222B (en) | 2012-12-31 | 2012-12-31 | A kind of pressure precise adjustment device |
| CN201210586305.6 | 2012-12-31 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2837786A1 true CA2837786A1 (en) | 2014-06-30 |
Family
ID=48204920
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA2837786A Abandoned CA2837786A1 (en) | 2012-12-31 | 2013-12-19 | Apparatus for precise pressure adjustment |
Country Status (3)
| Country | Link |
|---|---|
| CN (1) | CN103092222B (en) |
| CA (1) | CA2837786A1 (en) |
| WO (1) | WO2014101728A1 (en) |
Families Citing this family (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103092222B (en) * | 2012-12-31 | 2016-01-27 | 孙晓君 | A kind of pressure precise adjustment device |
| CN103116370B (en) * | 2013-01-04 | 2015-06-03 | 北京银谷科讯信息技术有限公司 | Pressure regulating device |
| CN106981556A (en) * | 2017-03-24 | 2017-07-25 | 广东顺德中山大学卡内基梅隆大学国际联合研究院 | It is a kind of can fine adjustment spacing expansion film machine and its adjusting method |
| CN110579329B (en) * | 2019-06-27 | 2024-04-19 | 中国空气动力研究与发展中心低速空气动力研究所 | Sub/transonic jet noise research test device |
| CN111381614B (en) * | 2020-03-26 | 2023-09-12 | 杭州汇健科技有限公司 | In-situ pressure acquisition micro-control device and control method thereof |
| CN112032380B (en) * | 2020-08-25 | 2022-03-22 | 中车青岛四方车辆研究所有限公司 | Pressure reducing device and closed-loop control method for pressure output regulation of pressure reducing device |
| CN112850207B (en) * | 2021-01-06 | 2023-04-18 | 内蒙古蒙维科技有限公司 | Method for controlling powder buffering and flow stabilizing warehouse weight warehouse pressure |
| CN112945461B (en) * | 2021-02-02 | 2022-05-20 | 同济大学 | Multifunctional pressure gauge automatic test system, method and device |
| US11964271B2 (en) | 2022-07-27 | 2024-04-23 | Pilot Gene Technology (hangzhou) Co., Ltd. | Drop preparation device and drop preparation method |
| CN115254217B (en) * | 2022-07-27 | 2023-12-01 | 领航基因科技（杭州）有限公司 | Droplet preparation device and method |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3941148A (en) * | 1975-04-17 | 1976-03-02 | Sun Oil Company Of Pennsylvania | Control valve drive |
| US4575313A (en) * | 1983-02-02 | 1986-03-11 | Halliburton Company | Digital pressure controller |
| CN101256417B (en) * | 2008-02-25 | 2010-06-16 | 周德海 | Proportional valve pair accurate atmosphere controller |
| CN201886370U (en) * | 2010-12-16 | 2011-06-29 | 河南省中分仪器有限公司 | Intelligent gas flow rate and pressure controller |
| CN102385397A (en) * | 2011-09-29 | 2012-03-21 | 北京振兴计量测试研究所 | High-precision pressure control system based on high-speed solenoid valve |
| CN103092222B (en) * | 2012-12-31 | 2016-01-27 | 孙晓君 | A kind of pressure precise adjustment device |
-
2012
- 2012-12-31 CN CN201210586305.6A patent/CN103092222B/en active Active
-
2013
- 2013-12-19 CA CA2837786A patent/CA2837786A1/en not_active Abandoned
- 2013-12-23 WO PCT/CN2013/090202 patent/WO2014101728A1/en active Application Filing
Also Published As
| Publication number | Publication date |
|---|---|
| CN103092222B (en) | 2016-01-27 |
| WO2014101728A1 (en) | 2014-07-03 |
| CN103092222A (en) | 2013-05-08 |
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