A system and method for testing thermal deformation of elastic roll

Abstract

The present invention provides a system and method for testing the thermal deformation of an elastic reel mechanism, and belongs to the technical field of spacecraft mechanisms. The system is used to test a reel-type extension rod mechanism, and the elastic reel in the reel-type extension rod mechanism is used as the reel to be tested; the system includes: a reference reel, a heating mechanism, a positioning mechanism, and a temperature measurement and control mechanism; the reference reel and the reel to be tested are completely the same elastic reel; the reference reel remains in an unfolded state; the reference reel and the reel-type extension rod mechanism are both arranged in the heating mechanism, and the reference reel and the reel to be tested are symmetrically arranged; the positioning mechanism is arranged outside the heating mechanism; the temperature measurement and control mechanism includes a temperature sensor and a temperature control device; the temperature sensor is arranged on the reference reel. The use of the present invention does not affect the unfolding and unfolding accuracy of the reel to be tested, has the advantages of high measurement accuracy, and has the advantages of simple construction, fast and efficient implementation, and low cost.

Description

Technical Field

[0001] The invention belongs to the technical field of spacecraft mechanisms, and in particular relates to a system and method for testing thermal deformation of an elastic roll. Background Art

[0002] The reel-type extension mechanism is a one-dimensional deployment mechanism. The mechanism adopts a mechatronic design to meet the requirements of a large storage ratio and a large deployment length. The deployment length can reach 5m to 10m, and its deployment length is mainly achieved by releasing the elastic reel. Thermal deformation is an important indicator that affects the pointing accuracy of the mechanism. Therefore, the thermal deformation of the elastic reel needs to be theoretically analyzed and experimentally verified. However, it is currently impossible to quantitatively analyze it theoretically. Therefore, it is particularly important to carry out experimental measurements of the thermal deformation of the elastic reel.

[0003] Chinese patent publication CN201210438969.8 discloses a heating method in which an infrared lamp array is arranged on the outside of a test product, a heat-insulating lampshade is arranged on the side of the infrared lamp array facing away from the test product, and heat is transferred to the test product by diffusion. Chinese patent publication CN201610616556.2 discloses a method in which a thermocouple is arranged on an antenna, and the antenna emissivity is calibrated by testing the surface temperature with a thermal imager, thereby indirectly measuring the antenna temperature. However, these two temperature measurement and control methods are only effective for stationary products and are not suitable for moving mechanisms. This is because the thermocouple is connected by a cable. If the thermocouple is directly attached to the tested mechanism, it will affect its unfolding and folding. Moreover, if the thermocouple is directly attached to an elastic reel, the glue used for attachment will cause certain contamination to the product surface.

[0004] Considering that the reel-type extension rod mechanism works in a space environment, it is ideal to measure thermal deformation in a vacuum, which can reduce the impact of air disturbance on the measurement. The commonly used vacuum simulation device is a vacuum tank. However, in order to maintain the vacuum degree, the vacuum tank needs a vacuum pump to work continuously, and the vibration of the vacuum pump will be transmitted to the product under test in the tank through the tank body, thus affecting the reliability of the test. In addition, the temperature rise and fall in the vacuum tank is very slow, and the measurement is more difficult. Therefore, testing in a vacuum tank is more disadvantageous than advantageous and is not a desirable test solution.

[0005] In order to solve the problem of temperature measurement, control and precision measurement of motion mechanisms, a new thermal deformation measurement system and method is needed. Summary of the invention

[0006] The purpose of the present invention is to solve the problems existing in the above-mentioned prior art and to provide a system and method for testing the thermal deformation of an elastic roll under normal temperature and pressure, which can realize the temperature measurement and control of the moving mechanism, and the temperature field is stable, the temperature measurement points are pasted in place at one time, and do not affect the movement of the mechanism.

[0007] The present invention is achieved through the following technical solutions:

[0008] In a first aspect of the present invention, a system for testing thermal deformation of an elastic roll is provided, wherein the system is used to test a roll-type stretching rod mechanism, and the elastic roll in the roll-type stretching rod mechanism is used as a roll to be tested; the system comprises: a reference roll, a heating mechanism, a positioning mechanism, and a temperature measurement and control mechanism;

[0009] The reference roll and the roll to be tested are completely identical elastic rolls; the reference roll is kept in an unfolded state;

[0010] The reference reel and the reel-type extension rod mechanism are both arranged in the heating mechanism, and the reference reel and the reel to be tested are arranged symmetrically;

[0011] The positioning mechanism is arranged outside the heating mechanism;

[0012] The temperature measuring and controlling mechanism comprises a temperature sensor and a temperature control device; the temperature sensor is arranged on the reference reel.

[0013] A further improvement of the present invention is that a plurality of temperature sensors are provided at different heights on the reference reel;

[0014] Two temperature sensors evenly distributed on the circumference are arranged at the same height;

[0015] The temperature sensors at two adjacent heights are 90° apart on the circumference.

[0016] A further improvement of the present invention is that the heating mechanism comprises a plurality of groups of heating devices;

[0017] Each set of heating devices includes: a frame vehicle, a light array frame and a light array;

[0018] The light array frame is installed on the frame vehicle and can move up and down on the frame vehicle;

[0019] The lamp array is mounted on the lamp array frame;

[0020] The lamp array includes a plurality of infrared lamp tubes and a heat-insulating lampshade;

[0021] The heat-insulating lampshade is installed on the lamp array frame; the heat-insulating lampshade is located between the infrared lamp tube and the lamp array frame.

[0022] A further improvement of the present invention is that the heating mechanism includes four groups of heating devices, namely a left heating device, a right heating device, a front heating device, and a rear heating device;

[0023] The four groups of heating devices are evenly distributed on the circumference, that is, the center point of the projection of the light array of each group of heating devices on the ground is located on the same circle, the center of the circle is used as the center of the heating mechanism, and the area within the circle is the heating area.

[0024] A further improvement of the present invention is that the reference reel and the reel-type extension rod mechanism are arranged in the heating area;

[0025] The central axes of the reference roll and the roll to be measured are both perpendicular to the ground, and the line connecting the projection of the central axis of the reference roll on the ground and the projection of the central axis of the roll to be measured on the ground forms an angle of 45 degrees with the line connecting the center points of the left heating device and the right heating device, and also forms an angle of 45 degrees with the line connecting the center points of the front heating device and the rear heating device;

[0026] The projection of the central axis of the reference reel on the ground and the projection of the central axis of the reel to be measured on the ground are at the same distance from the center of the heating mechanism, and a line connecting the two passes through the center of the heating mechanism.

[0027] A further improvement of the present invention is that the positioning mechanism includes three theodolites, and the three theodolites are all arranged outside the heating mechanism;

[0028] The first theodolite and the second theodolite are located on the Z axis and the Y axis of the coordinate system respectively. The third theodolite is arranged between the first theodolite and the second theodolite and forms an angle of 60° with the first theodolite.

[0029] A further improvement of the present invention is that a precision measuring target point and a measuring mirror are installed on the reel-type extension rod mechanism;

[0030] The measuring mirror is installed at the bottom of the reel-type extension rod mechanism;

[0031] The precision measurement target points include top targets and middle targets;

[0032] The top target is a spherical target ball installed on the top of the reel to be tested;

[0033] The intermediate target is installed on the lower auxiliary supporting cylindrical surface of the reel-type extension rod mechanism. The intermediate target includes a plurality of paper targets evenly distributed on the circumference, and the center of the circle is used as the center point of the intermediate target.

[0034] A further improvement of the present invention is that the system comprises two independent platforms;

[0035] The two platforms are arranged in the heating area;

[0036] The two platforms are installed on the ground, and each platform is provided with a mounting base for fixing the reference reel and the reel-type extension rod mechanism.

[0037] A further improvement of the present invention is that a barrier is provided between the heating mechanism and the positioning mechanism;

[0038] A lockable roller is installed at the bottom of the frame vehicle.

[0039] A second aspect of the present invention provides a method for testing thermal deformation of an elastic reel mechanism, the method comprising:

[0040] (1) Install the above-mentioned system for testing the thermal deformation of the elastic reel mechanism

[0041] (2) Measurement pointing accuracy:

[0042] (21) using a positioning mechanism to measure the coordinates of the center point of the intermediate target and the center point of the top target in the measuring mirror coordinate system, obtaining the pointing accuracy of the reel to be measured in the measuring mirror coordinate system, and then obtaining the pointing accuracy of the reel to be measured in the reference coordinate system by converting the measuring mirror coordinate system and the reference coordinate system; the pointing accuracy refers to the angle between the line connecting the center point of the intermediate target and the center point of the top target and the X-axis in the coordinate system;

[0043] (22) Test the pointing accuracy under different working conditions:

[0044] The heating mechanism is controlled by a temperature control device to heat the heating area so that the heating area is at different temperatures; different working conditions refer to different temperatures of the heating area;

[0045] Under each working condition, the reel to be tested is unrolled N times, and the pointing accuracy is obtained each time according to step (21), and the average value of the N pointing accuracies is taken as the pointing accuracy under the working condition.

[0046] Compared with the prior art, the present invention has the following beneficial effects:

[0047] (1) The present invention arranges thermocouples on the reference roll instead of on the roll to be tested, and uses the thermocouples on the reference roll to test the ambient temperature field. The temperature fields in the same area are the same to characterize the temperature of the symmetrically placed rolls to be tested, which does not affect the unwinding and unwinding accuracy of the roll to be tested.

[0048] (2) The present invention uses a theodolite to perform non-contact precision measurement, and the measurement will not introduce disturbance to the roll to be measured, which has the advantage of high measurement accuracy;

[0049] (3) The present invention uses a lamp array system to achieve heating, which has the advantage of not contacting the heated object. A heat-insulating lampshade is installed behind the lamp array, and a fence is installed outside the lamp array system, which improves the stability of the temperature field and the temperature control accuracy.

[0050] (4) The present invention is carried out at room temperature and pressure. Compared with the process in a vacuum tank, the present invention has the advantages of simple system construction, fast and efficient implementation, and low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 A schematic diagram of the structure of an elastic reel in a reel-type stretching rod mechanism tested by a system for testing thermal deformation of an elastic reel according to the present invention;

[0052] Figure 2 It is a layout diagram of the temperature measurement and control points in the system for testing the thermal deformation of the elastic roll of the present invention;

[0053] Figure 3 A three-dimensional structural diagram (including the arrangement of precise measuring points) of the elastic reel of the reel-type stretching rod mechanism in the unfolded state tested by the system for testing the thermal deformation of the elastic reel of the present invention;

[0054] Figure 4-1 It is a structural schematic diagram of a heating device in a system for testing thermal deformation of an elastic roll according to the present invention;

[0055] Figure 4-2 It is a schematic diagram of the structure of a lamp array in a lamp array system in a system for testing thermal deformation of an elastic roll according to the present invention;

[0056] Figure 4-3 A schematic structural diagram of a reference roll mounting base in a system for testing thermal deformation of an elastic roll according to the present invention;

[0057] Figure 5 A schematic diagram of the relative positions of the light array and the reel to be tested in a test system without using a reference reel;

[0058] Figure 6 The figure is a schematic diagram of the relative positions of the light array, the roll to be tested and the reference roll in the system for testing the thermal deformation of an elastic roll according to the present invention. DETAILED DESCRIPTION

[0059] The present invention is further described in detail below in conjunction with the accompanying drawings:

[0060] In order to measure the change of pointing accuracy of a reel-type extension rod mechanism in high and low temperature environments, the present invention proposes a thermal deformation test system of "light array + theodolite + reference reel".

[0061] Specifically, the elastic reel thermal deformation testing system of the present invention is used to test the elastic reel in the reel-type extension rod mechanism, and the elastic reel is used as the reel to be tested 2. The system of the present invention includes: a reference reel 1, a heating mechanism, a positioning mechanism, and a temperature measurement and control mechanism.

[0062] The reference roll 1 is an elastic roll that is identical to the roll to be tested 2. The materials and structures of the two rolls are identical. Figure 1During the experiment, the reference roll is always kept in the unfolded state, that is, stretched to the longest state, while the roll to be tested in the roll-type extension rod mechanism can be unfolded or retracted.

[0063] like Figure 6 As shown, the reference reel 1 and the reel-type stretching rod mechanism are both arranged in the heating mechanism, and the reference reel 1 is symmetrically arranged with the reel 2 to be measured in the reel-type stretching rod mechanism. The positioning mechanism is arranged outside the heating mechanism; the temperature measurement and control mechanism includes a temperature sensor and a temperature control device; the temperature sensor is arranged on the outer wall of the reference reel.

[0064] Embodiments of the present invention are as follows:

[0065] [Example 1]

[0066] A plurality of temperature sensors are arranged on the reference reel, and preferably, the temperature sensors are thermocouples. Figure 2 As shown, in this embodiment, 8 temperature sensors are arranged on the reference roll, including, from the top to the bottom, the seventh thermocouple and the eighth thermocouple arranged 500 mm from the top, the fifth thermocouple and the sixth thermocouple arranged 1200 mm from the top, the third thermocouple and the fourth thermocouple arranged 1900 mm from the top, and the first thermocouple and the second thermocouple arranged 2600 mm from the top.

[0067] The two thermocouples at the same height are arranged symmetrically, that is, they are 180° apart on the circumference, and the thermocouples at two adjacent heights are 90° apart on the circumference. In actual use, the position and number of the thermocouples installed on the reference reel can be increased or decreased according to actual needs. The thermocouple can be an existing conventional thermocouple, which can be directly pasted on the reference reel.

[0068] [Example 2]

[0069] The heating mechanism includes multiple groups of heating devices, such as Figure 4-1 As shown, each set of heating devices includes: a frame car 403, a lamp array frame 402 and a lamp array 401. The lamp array frame 402 is installed on the frame car 403 and can move up and down on the frame car 403 to adjust the height. The lamp array 401 is installed on the lamp array frame. The bottom of the frame car 403 is equipped with a lockable roller (a commercially available product can be used).

[0070] Specifically, a plurality of threaded holes arranged in the longitudinal direction are opened on the upper part of the frame car 403, and a plurality of threaded holes arranged in the longitudinal direction are also opened on the lamp array frame 402. Bolts are passed through the threaded holes on the lamp array frame and the frame car in turn and then connected with nuts. The lamp array frame is fixed to the frame car by bolts. The lamp array frame can be fixed at different heights on the frame car through threaded holes at different heights.

[0071] In this embodiment, the frame vehicle 403 includes four lower columns perpendicular to the ground, the projections of the four lower columns on the horizontal plane are four vertices of a rectangle, a plurality of beams are arranged from top to bottom between two adjacent lower columns, and the four lower columns are connected to form a rectangular frame structure through the beams, and two mounting columns parallel to the lower columns are arranged between two of the lower columns, and a plurality of threaded holes are opened on each mounting column from top to bottom. The frame vehicle can be welded by a square aluminum tube with a cross section of 40mmX40mm and a tube thickness of 5mm. A lockable roller is installed at the bottom end of each column, which is convenient for moving and adjusting the position and positioning of the infrared lamp.

[0072] The light array frame in this embodiment is a triangular prism frame structure, including three upper columns perpendicular to the ground, namely the first column, the second column 402 and the third column. The projections of the three columns on the horizontal plane are the three vertices of a triangle, and multiple short beams are used to connect two adjacent columns. There are multiple threaded holes on the first column and the second column from top to bottom, and the distance between the two columns is the same as the distance between the two mounting columns on the frame car. The two columns are installed on the two mounting columns on the frame car by bolts. The light array is installed on the third column in the light array frame, and the third column provides a mounting fulcrum for the light array. The light array frame can be welded with a 30mmX30mm square aluminum tube with a tube thickness of 2.5mm.

[0073] Preferably, the light array frame 402 and the frame vehicle 403 are connected by two rows of M12 bolts, and can be adjusted up and down, that is, the height of the light array frame can be adjusted.

[0074] [Example 3]

[0075] The lamp array 401 includes a plurality of infrared lamp tubes 4011 and a plurality of heat-insulating lampshades 4012. The infrared lamp tubes 4011 correspond to the heat-insulating lampshades 4012 one by one. The structure of one infrared lamp tube 4011 and one heat-insulating lampshade 4012 is as follows: Figure 4-2As shown. The heat-insulating lampshade 4012 is installed on the third column in the lamp array frame 402, and an infrared lamp tube 4011 is installed in front of the heat-insulating lampshade 4012, that is, the heat-insulating lampshade 4012 is located between the infrared lamp tube 4011 and the lamp array frame 402. In this way, the heat-insulating lampshade 4012 is arranged behind the lamp tube, which ensures that the lamp tube only heats the front and does not heat the lamp array frame at the rear, thereby ensuring that the lamp array frame will not be deformed due to temperature rise. Because the deformation of the lamp array frame will cause the position of the lamp array to change, and then cause the heating position to change, and the change in the heating position will affect the test accuracy, the present invention ensures that the lamp array frame does not deform through the heat-insulating lampshade, thereby ensuring the test accuracy. The infrared lamp tube and the heat-insulating lampshade are both existing products and will not be described in detail here.

[0076] [Example 4]

[0077] The heating mechanism includes 4 groups of heating devices, namely, a left heating device, a right heating device, a front heating device, and a rear heating device. The four groups of heating devices are evenly distributed on the circumference, that is, the center point of the projection of the light array of each group of heating devices on the ground is located on the same circle, and the center of the circle is used as the center of the heating mechanism. The center points of the four projections are evenly distributed on the circumference, and the lines connecting the center points of the left heating device and the right heating device, and the lines connecting the center points of the front heating device and the rear heating device are perpendicular to each other. The area within the circle is the heating area.

[0078] [Example 5]

[0079] The reference reel and the reel-type stretching mechanism to be tested are arranged in a circle surrounded by four groups of heating devices, and both are arranged vertically, that is, the central axes of the reference reel and the reel to be tested are both perpendicular to the ground, and the line connecting the projection of the central axis of the reference reel on the ground and the projection of the central axis of the reel to be tested on the ground forms a 45-degree angle with the line connecting the center points of the left heating device and the right heating device, and also forms a 45-degree angle with the line connecting the center points of the front heating device and the rear heating device, and the distance between the projection of the central axis of the reference reel on the ground and the projection of the central axis of the reel to be tested on the ground to the center of the heating mechanism is the same, and the line connecting the two passes through the center of the heating mechanism. Through this arrangement, the reference reel and the reel to be tested are in the same temperature field, and the two are placed symmetrically, so that the temperature of the thermocouple on the reference reel can characterize the temperature of the reel to be tested at the same position of the reel-type stretching mechanism to be tested.

[0080] Figure 5 The method is to directly measure the roll to be tested by sticking a thermocouple on the roll to be tested of the roll-type extension rod mechanism. Because of the sticking of the thermocouple, the roll to be tested can only be in an unfolded state and cannot be folded, so the deformation cannot be measured. Figure 6The present invention is a test system that arranges a reference reel and a reel-type extension rod mechanism, and the reel-type extension rod mechanism can unfold and retract the reel to be tested. Figure 6 The line connecting the front and rear light arrays is perpendicular to the line connecting the left and right light arrays. The intersection of the two lines is the center of the heating mechanism. The line connecting the central axes of the reference roll and the elastic roll projected on the horizontal plane passes through the center of the heating mechanism, and the distances from the two to the center of the heating mechanism are equal, which reduces the mutual shading effect between the two rolls and ensures that the temperatures of the two are the same.

[0081] [Example 6]

[0082] The positioning mechanism includes three theodolites, all of which are arranged outside the heating mechanism. Preferably, the first theodolite is located on the Z axis of the reel-type extension mechanism, and the second theodolite is located on the Y axis of the reel-type extension mechanism, and the two are arranged at 90°. The origin of the XYZ axis is the center point of the measuring mirror, which is obtained by measuring the crosshairs at the center of the measuring mirror surface. The third theodolite is arranged between the first theodolite and the second theodolite, and the angle with the first theodolite is about 60°. The first theodolite and the second theodolite are about 2m away from the center of the heating mechanism, and the third theodolite is 3-3.5m away from the center of the heating mechanism.

[0083] [Example 7]

[0084] like Figure 3 As shown, in order to measure thermal deformation, a precision measurement target point and a measuring mirror 302 are installed on the roll-type extension rod mechanism to be measured. The measuring mirror 302 is glued to the bottom of the roll-type extension rod mechanism to be measured by epoxy glue. The gluing position is based on the convenience of theodolite measurement. The measuring mirror 302 is installed at the bottom to avoid being heated by the light array, thereby introducing measurement errors. The measuring mirror can use an existing cubic mirror.

[0085] The precision measuring target points are arranged on the reel to be measured. Specifically, the precision measuring target points include a top target 304 and an intermediate target 303. The top target is a spherical target ball, which is installed on the top of the reel to be measured through the thread at the top of the reel to be measured. The intermediate target 303 is a paper target, which is adhered to the lower auxiliary support cylindrical surface of the reel-type extension mechanism with double-sided adhesive. The position of the intermediate target 303 remains unchanged and does not expand and contract with the reel. The periphery of the intermediate target 303 is pressed and fixed with 3M adhesive tape. The intermediate targets 303 are evenly arranged around the cylindrical surface, and 5-6 targets can be arranged.

[0086] The height of the first and second theodolites is limited by the measuring mirror installed on the drum-type extension rod mechanism, and is about 1.2-1.5m. The height of the third theodolite is not limited, and is generally about 2m.

[0087] The first and second theodolites are connected to build a station, responsible for measuring the measuring mirror on the reel-type extension rod mechanism and measuring the measuring mirror coordinate system. The first and third theodolites are connected to build a station, responsible for measuring the middle target 303 and the top target 304, so as to calculate the axis of the reel. The three theodolites are connected to calculate the positions of the middle target 303 and the top target 304 of the reel-type extension rod mechanism in the measuring mirror coordinate system. By measuring at different temperatures, the thermal deformation data of the reel can be obtained. The theodolite can be a commercially available product. The theodolite measures angular physical quantities. By connecting two or more theodolites to build a station and calibrating a ruler of known length, a three-dimensional three-coordinate measurement system can be established. Points and lines in the system can be measured, so as to further calculate the position and angle relationship.

[0088] [Embodiment 8]

[0089] The system also includes a temperature control device, and the data collected by the thermocouple is sent to the temperature control device. The temperature control device controls each infrared lamp tube by combining closed-loop automatic control with manual current limiting. The current value of the infrared lamp tube under each working condition is adjusted in real time according to the temperature fluctuation collected by the corresponding thermocouple, and has storage, display, printing and timely drawing functions, alarm, protection and anti-interference capabilities. The temperature control device uses existing equipment, and the control method is also an existing mature technology, which will not be repeated here.

[0090] [Example 9]

[0091] Furthermore, the system includes two independent platforms, which are used to support the reference reel and the mechanism to be tested respectively. The two platforms are arranged in the heating area, and the heating device is arranged around the two platforms. The two platforms are installed on the ground. In order to install the reel-type extension rod mechanism and the reference reel on the platform, a mounting base is provided on each platform. The reference reel is fixed on a special reference reel mounting base. The structure of the base is as follows: Figure 4-3 As shown, it is a cylindrical structure with a central through hole, and the lower end of the base is connected to the platform as a whole. The reference reel mounting base is made of steel material, and a glass fiber reinforced plastic pad is added between the base and the reference reel for insulation. For example, the glass fiber reinforced plastic cloth can be cut and wrapped between the reel and the base to form insulation between the two.

[0092] The reel-type extension rod mechanism is fixed on the reel-to-be-tested mounting base, which is welded from profiles and connected to the platform at its bottom. An aluminum plate is installed on the reel-to-be-tested mounting base to provide a mounting interface for the reel-type extension rod mechanism. The reel-type extension rod mechanism can be installed on the base through flange 301, and ensure that the central axis of the reel-to-be-tested is perpendicular to the ground.

[0093] [Example 10]

[0094] Furthermore, in order to prevent the airflow from causing vibration of the reference reel and the reel to be tested, a fence is provided on the periphery of the heating mechanism, the fence is arranged close to the heating mechanism, and the fence is located between the theodolite and the heating mechanism. When the fence is arranged, the connection line between the middle target 303, the top target B and the theodolite is exposed, which is convenient for theodolite measurement. The purpose of using the fence is to reduce the large airflow formed due to uneven temperature in the test site, thereby reducing the impact on the test accuracy.

[0095] Considering the large temperature difference between the heating area and the surrounding atmosphere, the thermal boundary of the entire system is unstable and temperature control is difficult. When designing the system, under the premise of ensuring the uniform temperature field in the heating area, the circle formed by the heating device in the present invention should be as small as possible, and the enclosure should ensure that the surrounding space has good barrier properties, so that the heating area is isolated from the surrounding space, which is conducive to temperature control and can improve test efficiency and accuracy.

[0096] The present invention arranges multiple heating devices on a circumference to form a stable temperature field. In the temperature field, a set of reel-type extension rod mechanism and a reference reel are symmetrically arranged. A thermocouple is arranged on the reference reel, and the temperature collected by the thermocouple on the reference reel is used to replace the temperature of the reel-type extension rod mechanism. The non-contact precision measurement is performed by using theodolite online station building method, and no disturbance to the mechanism is introduced during the measurement. It has the advantages of mature measurement method and high measurement accuracy.

[0097] The method for accurately measuring the thermal deformation of the elastic roll using the above system includes:

[0098] (1) Install the above system as follows:

[0099] (11) Keep the roll-type extension rod mechanism to be tested in an unexpanded state and adjust it to be perpendicular to the platform to reduce the influence of gravity on the unfolding accuracy of the roll-type extension rod mechanism to be tested during the unfolding process. Install the roll-type extension rod mechanism to be tested on the platform; insert the lower end of the reference roll into the reference roll mounting base, and keep the reference roll in a fully unfolded state. The reference roll is kept in the unfolded state. Since the roll-type extension rod mechanism to be tested needs to be unfolded and retracted during the test process, the length and position of the reference roll can cover the measurement range of the roll-type extension rod mechanism to be tested.

[0100] (12) A thermocouple is attached to the reference roll to control the temperature fluctuation in the heating area within a range of 1°C. In this embodiment, four groups of heating devices are symmetrically arranged on the periphery of the platform, and each group of heating devices is provided with 7-9 infrared lamps. The strength of each infrared lamp is controlled by the thermocouple on the reference roll, thereby controlling the temperature field in the entire area. The temperature fluctuation can be controlled within a range of 1°C by the spacing of the heating devices and the number of infrared lamps. The reference roll is unfolded, and the thermocouple on the reference roll can provide the temperature of the entire temperature field from bottom to top. The roll to be tested of the roll-type extension mechanism can be unfolded to different heights, so that the thermal deformation at different heights can be measured.

[0101] (13) Installing the precision measurement target point and the measuring mirror on the reel-type extension rod mechanism to be measured;

[0102] (14) Arrange multiple groups of heating devices around the periphery of the platform. The radius of the circle where the heating devices are located is determined according to the heating capacity and is generally controlled within More suitable;

[0103] (15) Three theodolites are arranged around the periphery of the heating mechanism, and a positioning mechanism is used to measure the basic relationship between the measuring mirror and the target point. This basic relationship refers to the coordinate value of the target point in the cubic mirror coordinate system.

[0104] (15) Arrange a barrier between the positioning mechanism and the heating mechanism;

[0105] (2) Measurement pointing accuracy:

[0106] (21) Use a positioning mechanism to measure the coordinates of the center point of the middle target 303 and the center point of the top target 304 in the measuring mirror coordinate system (a three-axis coordinate system with the center of the measuring mirror as the origin).

[0107] The middle target 303 includes a plurality of paper targets evenly distributed on the circumference. The coordinates of the center of the circle can be obtained through the coordinates of the centers of the plurality of paper targets, and the center of the circle is taken as the center point of the middle target 303. The top target 304 is a target ball, which is located on the central axis of the roll. The center of the target ball is the center point of the top target 304. The pointing accuracy of the line connecting the center point of the middle target 303 and the center point of the top target 304 (i.e., the line connecting the two center points) in the measuring mirror coordinate system can be calculated based on the coordinates of the two center points. Then, by converting the measuring mirror coordinate system and the reference coordinate system, the pointing accuracy of the roll to be measured in the reference coordinate system at room temperature (the reference coordinate system refers to Figure 3 The coordinate system formed by the cylinder and the triangle plate at the bottom of the reel-type stretching rod mechanism in the drawing is the origin of the intersection of the axis of the cylinder and the upper surface of the triangle plate, and the X direction is the upward direction of the axis of the cylinder. ) pointing accuracy.

[0108] The pointing accuracy refers to the angle between the line connecting the center point of the middle target 303 and the center point of the top target 304 and the X-axis of the coordinate system. Of course, other coordinate systems can also be set, as long as the pointing accuracy in the measuring mirror coordinate system is converted to the new coordinate system.

[0109] (22) Test the pointing accuracy under different working conditions:

[0110] Different working conditions refer to different temperatures of the heating area. In this embodiment, the pointing accuracy under three working conditions is measured. The three working conditions are: the temperature of the heating area is 30°C, 60°C, and 90°C respectively. The temperature of the heating area is obtained by obtaining the average temperature of all thermocouples on the reference reel, that is, the average of the measured values ​​of all thermocouples is taken as the temperature of the heating area. The pointing accuracy under more working conditions can also be measured as needed.

[0111] In each working condition, the temperature change of each temperature measuring point is controlled within the range of 0°C to 4°C. In each working condition, the reel to be tested is unfolded 3 times (of course, it can be unfolded more times as needed). The reel to be tested is counted as one time when it changes from a folded state to an unfolded state. The pointing accuracy is measured each time to obtain 3 pointing accuracies. The measurement method is the same as step (21). The average value of the 3 pointing accuracies is taken as the pointing accuracy under this working condition. Specifically, for example, to measure the pointing accuracy under a 30-degree working condition, the temperature of the heating area is maintained at 30 degrees, the reel to be tested is unfolded, the first measurement is taken, and then the reel to be tested is folded, unfolded for the second time, the second measurement is taken, folded again, and then unfolded for the third time and the third measurement is taken. When changing from one temperature working condition to the next temperature working condition, it is necessary to wait for the temperature of each thermocouple (8 thermocouples in this embodiment) to stabilize within the range of 0-4 degrees before starting the measurement under the new temperature working condition. This ensures temperature stability.

[0112] At the same temperature, the instrument is expanded and folded three times, and a set of pointing accuracy is measured each time with a theodolite. In this way, there are three pointing accuracies at the same temperature. By comparing the three pointing accuracies at the same temperature horizontally, the stability and repeatability of the test can be obtained. By comparing the pointing accuracies at different temperatures vertically, the influence of temperature on the pointing accuracy can be obtained.

[0113] The present invention solves the temperature measurement problem of the motion mechanism and the problem of too long temperature rise and fall in the vacuum system; it also solves the pollution problem caused by directly sticking thermocouples on the product surface by the traditional method; at the same time, a heat-insulating lampshade is arranged between the infrared lamp and the frame to avoid thermal deformation caused by heating the frame, thereby improving the test accuracy; and further improving the reliability of the test, greatly reducing the test cost.

[0114] The above technical solution is only one implementation mode of the present invention. For those skilled in the art, it is easy to make various types of improvements or modifications based on the application methods and principles disclosed in the present invention, and it is not limited to the method described in the above specific implementation mode of the present invention. Therefore, the method described above is only preferred and does not have a restrictive meaning.

Claims

1. A system for testing thermal deformation of an elastic reel mechanism, the system being used to test a reel-type stretching rod mechanism, wherein the elastic reel in the reel-type stretching rod mechanism is used as the reel to be tested; characterized in that: The system comprises: a reference roll, a heating mechanism, a positioning mechanism, and a temperature measurement and control mechanism; The reference roll and the roll to be tested are completely identical elastic rolls; the reference roll is kept in an unfolded state; The reference reel and the reel-type extension rod mechanism are both arranged in the heating mechanism, and the reference reel and the reel to be tested are arranged symmetrically; The positioning mechanism is arranged outside the heating mechanism; The temperature measurement and control mechanism comprises a temperature sensor and a temperature control device; the temperature sensor is arranged on the reference reel; and the data collected by the temperature sensor is sent to the temperature control device.

2. The system for testing thermal deformation of an elastic reel mechanism according to claim 1, characterized in that: A plurality of temperature sensors are arranged at different heights on the reference reel; Two temperature sensors evenly distributed on the circumference are arranged at the same height; The temperature sensors at two adjacent heights are 90° apart on the circumference.

3. The system for testing thermal deformation of an elastic reel mechanism according to claim 2, characterized in that: The heating mechanism includes multiple groups of heating devices; Each set of heating devices includes: a frame vehicle, a light array frame and a light array; The light array frame is installed on the frame vehicle and can move up and down on the frame vehicle; The lamp array is mounted on the lamp array frame; The lamp array includes a plurality of infrared lamp tubes and a heat-insulating lampshade; The heat-insulating lampshade is installed on the lamp array frame; the heat-insulating lampshade is located between the infrared lamp tube and the lamp array frame.

4. The system for testing thermal deformation of an elastic reel mechanism according to claim 3, characterized in that: The heating mechanism includes four groups of heating devices, namely a left heating device, a right heating device, a front heating device, and a rear heating device; The four groups of heating devices are evenly distributed on the circumference, that is, the center point of the projection of the light array of each group of heating devices on the ground is located on the same circle, the center of the circle is used as the center of the heating mechanism, and the area within the circle is the heating area.

5. The system for testing thermal deformation of an elastic reel mechanism according to claim 4, characterized in that: The reference reel and the reel-type extension rod mechanism are arranged in the heating area; The central axes of the reference roll and the roll to be measured are both perpendicular to the ground, and the line connecting the projection of the central axis of the reference roll on the ground and the projection of the central axis of the roll to be measured on the ground forms an angle of 45 degrees with the line connecting the center points of the left heating device and the right heating device, and also forms an angle of 45 degrees with the line connecting the center points of the front heating device and the rear heating device; The projection of the central axis of the reference reel on the ground and the projection of the central axis of the reel to be measured on the ground are at the same distance from the center of the heating mechanism, and a line connecting the two passes through the center of the heating mechanism.

6. The system for testing thermal deformation of an elastic reel mechanism according to claim 5, characterized in that: The positioning mechanism includes three theodolites, and the three theodolites are all arranged outside the heating mechanism; The first theodolite and the second theodolite are located on the Z axis and the Y axis of the coordinate system respectively. The third theodolite is arranged between the first theodolite and the second theodolite and forms an angle of 60° with the first theodolite.

7. The system for testing thermal deformation of an elastic reel mechanism according to claim 6, characterized in that: A precision measuring target point and a measuring mirror are installed on the reel-type extension rod mechanism; The measuring mirror is installed at the bottom of the reel-type extension rod mechanism; The precision measurement target points include top targets and middle targets; The top target is a spherical target ball installed on the top of the reel to be tested; The intermediate target is installed on the lower auxiliary supporting cylindrical surface of the reel-type extension rod mechanism. The intermediate target includes a plurality of paper targets evenly distributed on the circumference, and the center of the circle is used as the center point of the intermediate target.

8. The system for testing thermal deformation of an elastic reel mechanism according to claim 7, characterized in that: The system comprises two independent platforms; The two platforms are arranged in the heating area; The two platforms are installed on the ground, and each platform is provided with a mounting base for fixing a reference reel and a reel-type extension rod mechanism.

9. The system for testing thermal deformation of an elastic reel mechanism according to claim 8, characterized in that: An enclosure is provided between the heating mechanism and the positioning mechanism; A lockable roller is installed at the bottom of the frame vehicle.

10. A method for testing thermal deformation of an elastic reel mechanism, characterized in that: The method comprises: (1) Install the system for testing thermal deformation of an elastic reel mechanism as described in any one of claims 1 to 9; (2) Measurement pointing accuracy: (21) using a positioning mechanism to measure the coordinates of the center point of the intermediate target and the center point of the top target in the measuring mirror coordinate system, obtaining the pointing accuracy of the reel to be measured in the measuring mirror coordinate system, and then obtaining the pointing accuracy of the reel to be measured in the reference coordinate system by converting the measuring mirror coordinate system and the reference coordinate system; the pointing accuracy refers to the angle between the line connecting the center point of the intermediate target and the center point of the top target and the X-axis in the coordinate system; (22) Test the pointing accuracy under different working conditions: The heating mechanism is controlled by a temperature control device to heat the heating area so that the heating area is at different temperatures; different working conditions refer to different temperatures of the heating area; Under each working condition, the reel to be tested is unrolled N times, and the pointing accuracy is obtained each time according to step (21), and the average value of the N pointing accuracies is taken as the pointing accuracy under the working condition.

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