CN102809801A - Pneumatic type support system of primary mirror of astronomical telescope - Google Patents

Abstract

The pneumatic support system of the main mirror of the astronomical telescope, the key component is the pneumatic force actuator system, the force output end of the force actuator is connected with the mirror surface through the force sensor, and the characteristic is that the force actuator adopts the principle of pneumatic to realize the force exact output. According to the force signal fed back to the control system by the force sensor, the control system controls the gas pressure at both ends of the piston arranged in the cylinder through the electro-pneumatic proportional valve. The invention is composed of an ultra-low friction cylinder, a high-precision electric-pneumatic proportional valve and a force sensor closed loop, which can precisely control the output force of the actuator, and its response frequency can reach more than 1HZ, and at the same time, the required force sensor can be set. The stroke range, and by setting the air pressure range, a larger force range can be achieved, and it can be used in extremely harsh environments such as the Antarctic, and has lower environmental requirements.

Description

Pneumatic support system for primary mirror of astronomical telescope

technical field

The invention relates to a support system for a main mirror of a telescope, in particular to a set of aerodynamic active support system for a main mirror of an astronomical telescope. It is mainly used in the active optical mirror support technology of astronomical telescopes. Axial support for thin mirrors or lightweight mirrors and active optical correction or position adjustment of the mirror surface.

Background technique

Active optics technology is mainly to correct the mirror surface shape errors caused by the manufacture, installation, gravity field, and temperature gradient of the telescope mirror. In the past two decades, active optics technology has been widely used in ground-based telescopes. The active optical support system is one of the key technologies in the design of large aperture telescopes. As the most important component in the design of the active optical mirror support system, the force actuator has always been one of the focuses of active optical technology research. At present, there are mainly two forms of force actuators used in the active optics research of astronomical telescopes in my country: electromechanical and piezoelectric. The electromechanical force actuator mainly realizes the linear displacement by the combination of the stepping motor and the ball screw, and realizes the precise output of the force through the compression spring or the sealed bellows structure. Its mechanical structure is relatively complicated, and it is affected by the mechanical inertia and the driving motor , the operating frequency is generally difficult to reach more than 1Hz, when used in a low temperature environment (such as Antarctica), higher requirements are put forward for the lubrication of mechanical parts of the transmission system, and its reliability will be seriously reduced. Piezoelectric force actuators mainly use the inverse piezoelectric effect of some dielectrics, that is, when an electric field is applied in the polarization direction of the dielectric, these dielectrics will deform. After the electric field is removed, the deformation of the dielectric will disappear, or called Although the electrostrictive phenomenon has the advantages of high precision and high frequency, it is difficult to overcome the shortcomings of high heat generation and low travel. For environments such as the Antarctic where energy consumption is limited, its application is also severely restricted. the

Contents of the invention

For the active support system of the main mirror of the telescope in the prior art, in order to avoid the complicated mechanical structure due to the use of the electromechanical force actuator, and improve the response frequency of the output force of the actuator, overcome the high energy consumption of the piezoelectric active support, Disadvantages such as high cost and low travel. The invention proposes a pneumatic support scheme for the main mirror of the telescope. The pneumatic force actuator adopted can realize the characteristics of fast response, large stroke and high control precision, and also has the characteristics of low energy consumption and low temperature resistance. This type of pneumatic support scheme for the active support of the main mirror of the telescope can be used in extreme environments such as the Antarctic.

The technical solution adopted by the present invention to solve the technical problem is: a pneumatic support system for the primary mirror of an astronomical telescope, the key is to use a pneumatic force actuator, the force output end of the pneumatic force actuator is passed through the force sensor Connected with the mirror surface, it is characterized in that the force output end of the force actuator is a piston and a piston rod arranged in the cylinder; the output signal of the force sensor is connected to the control system, and the control system passes through the electric-pneumatic proportional valve, The gas pressure at both ends of the piston arranged in the cylinder is controlled, so as to realize the precise output of force. The pneumatic force actuator uses the principle of pneumatics, and the control system controls the gas pressure at both ends of the piston in the cylinder through the electro-pneumatic proportional valve, so as to realize the precise output of force and the support of the mirror surface and active calibration.

In the above technical solution, the structure of the pneumatic force actuator is: the air compressor supplies air to both ends of the cylinder of the pneumatic force actuator through the electric-pneumatic proportional valve, and the output of the force sensor is connected to the adjustment control system, the adjustment control system is connected to the coil of the electro-pneumatic proportional valve.

The primary mirror aerodynamic support scheme of the present invention has the following optimization schemes:

1. The cylinder of the force actuator adopts an ultra-low friction cylinder;

2. An overload protection structure is provided between the force output end of the force actuator and the force sensor;

3. The force actuator adopts an electric-pneumatic proportional valve, and its specific structure is: one end of the electric-pneumatic proportional valve is provided with a magnetic body, and a coil is provided outside the magnetic body, and the current in the coil is controlled by the control system; The magnetic body is connected with the valve core in the valve body; the three valve pistons on the valve core respectively correspond to the air inlet and the air outlet, and correspond to the air passages at both ends of the piston in the force actuator cylinder.

In other words, the technical solution adopted by the present invention to solve its technical problems is: adopt a pneumatic force actuator to realize the active support of the telescope mirror. This type of pneumatic force actuator is mainly composed of an ultra-low friction cylinder, force sensor, signal amplifier, electric- It is composed of air proportional valve, control system and air compressor. The structure of the system is extremely simple, there are almost no units such as mechanical transmission, and no lubrication is required. The effect of low temperature conditions on the performance of the actuator can be prevented. Using the pressure difference between the compressed air in the two chambers of the cylinder and the pressure on both sides of the cylinder piston, after overcoming the extremely low friction force, the force of the force actuator on the mirror is realized. By controlling the pressure on both sides of the cylinder piston, the actuator is realized. The pull or push of the mirror. The function of the spring in the electromechanical force actuator is realized by using the compressibility of the gas. Due to the high sensitivity of the control of the electro-pneumatic proportional valve, the pressure of the compressed air on both sides of the cylinder piston can be precisely controlled. Therefore, the high response and high precision of the force actuator output force can be ensured, and the ultra-low friction diaphragm cylinder can reduce the influence of friction on control accuracy and energy consumption. The control of the electro-pneumatic proportional valve only requires a low voltage of a few volts, thus reducing energy consumption to a great extent. Under the condition that the air pressure difference on both sides of the piston needs to be kept constant, a large axial stroke of the force actuator can be realized. The requirements for the environment are extremely low, and only filtered and dried air is required, so it can be used in the low-temperature and dry conditions of the Antarctic.

The beneficial effects of the invention are: the active optical support of the main mirror of the telescope is realized by adopting the pneumatic support method, the structure of the force actuator is relatively simple, the control precision of the output force is high, the response speed is fast, the energy consumption is low, and the mass is small. The stroke is large, the adjustment range of the force is wide, and its requirements on the environment are low, and it can be used in extreme low temperature environments such as Antarctica.

Description of drawings

Figure 1 is a schematic structural view of the present invention.

Detailed ways

Embodiment 1, the pneumatic support system of the primary mirror of the astronomical telescope, with reference to Fig. 1: the force output end 2 of the pneumatic force actuator is connected with the mirror surface 4 through the force sensor 3, when the air compressor passes through the electric-pneumatic proportional valve 7 pairs Cylinder 1 supplies air, and adjusts control system 8 so that when the output signal of force sensor 3 is fed back to control system 8 through signal amplifier 5, the active force is zero. At this time, the input voltage of control system 8 to the coil of electro-pneumatic proportional valve 7 is Balanced voltage, whose value is between 0 and 10V (required input voltage signal value of the electric-pneumatic proportional valve). When the force actuator is required to apply thrust to the mirror surface, increase the input voltage of the control system to the electro-pneumatic proportional valve 7, at this time, the current in the coil of the electro-pneumatic proportional valve 7 increases, the magnetism is enhanced, and the gravitational force to the magnetic material is increased. Large, the spool of the electric-pneumatic proportional valve 7 moves to the right, and part of the high-pressure gas in the cavity _V4 flows out through the overflow port on the right, so that the air pressure in the cavity _V2 of the cylinder 1 decreases, and the electric-pneumatic proportional valve The overflow port at the chamber V ₃ on the left side of the valve 7 is closed, the amount of compressed air entering the chamber V ₁ of the cylinder 1 increases, and the air pressure in the chamber V ₁ increases, so that the pressure at the end of the piston V1 of the cylinder 1 is greater than that of the piston V ₂ end, causing the cylinder 1 to produce a thrust on the mirror. Conversely, when the force actuator is required to apply pulling force to the mirror, reduce the input voltage of the control system to the electro-pneumatic proportional valve 7, at this time, the current in the coil of the electro-pneumatic proportional valve 7 decreases, the magnetism weakens, and the magnetic material The gravitational force of 6 becomes smaller, the spool of the electro-pneumatic proportional valve 7 moves to the left, and part of the high-pressure gas in the cavity _V3 flows out through the overflow port on the left side, so that the air pressure in the cavity V1 of the cylinder ₁ decreases, and The overflow port at the cavity V ₄ on the left side of the electric-pneumatic proportional valve 7 is closed, the amount of compressed air entering the cavity V ₂ of the cylinder 1 increases, and the air pressure in the cavity V ₂ increases, so that the piston at the V ₂ end of the cylinder 1 The pressure is greater than that of piston _V1 , causing cylinder 1 to pull on the mirror. In this process, it is necessary to gradually adjust the input voltage value of the electro-pneumatic proportional valve 7 according to the pressure value fed back by the pressure sensor 3 through the signal amplifier 5, which is a closed-loop control process until the force of the actuator on the mirror surface is equal to the required value. value.

Claims (5)

1. A pneumatic support system for the primary mirror of an astronomical telescope, the force output end of the force actuator is connected with the mirror surface by a force sensor, it is characterized in that the force actuator adopts a pneumatic force actuator, utilizing the principle of pneumatic, The gas pressure at both ends of the piston in the cylinder is controlled by the control system through the electro-pneumatic proportional valve, so as to realize the precise output of force, and realize the support and active correction of the mirror surface shape. 2. The pneumatic support system of the main mirror of the astronomical telescope according to claim 1, wherein the structure of the pneumatic force actuator is: the air compressor pushes the pneumatic force respectively through the electric-pneumatic proportional valve. The two ends of the cylinder of the actuator are supplied with air, the output of the force sensor is connected to the adjustment control system, and the adjustment control system is connected to the coil of the electro-pneumatic proportional valve. 3. the pneumatic support system of the main mirror of astronomical telescope according to claim 1, is characterized in that, the pneumatic support method of the main mirror of telescope according to claim 1, is characterized in that, actuating There is an overload protection structure between the force output end of the device and the force sensor. 4. the pneumatic support system of astronomical telescope main mirror according to claim 1, is characterized in that, the cylinder of described power actuator adopts ultra-low friction cylinder. 5. The pneumatic support system for the main mirror of the astronomical telescope according to any one of claims 1-4, wherein the specific structure of the electro-air proportional valve is: one end of the electro-air proportional valve is provided with a magnetic The magnetic body is provided with a coil outside, and the current in the coil is controlled by the control system; the magnetic body is connected to the valve core in the valve body; the three valve pistons on the valve core are respectively. 6. According to claim 5 The pneumatic support system for the primary mirror of the astronomical telescope is characterized in that the input voltage signal value of the electro-pneumatic proportional valve is between 0 and 10V.

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