Automatic coating equipment and method for variable-thickness ultralow-density heat-proof coating

Abstract

The invention relates to automatic coating equipment and method for a variable-thickness ultra-low-density heat-proof coating, and belongs to the technical field of surface engineering heat protection coatings. The automatic coating equipment comprises a spraying robot, a spraying programming system, a servo rotating table, an automatic coating viscosity controller, a flow controller, an automatic terahertz thickness measuring system, an industrial personal computer and the like; performing spraying program programming on the workpiece through a spraying programming system; the spraying robot clamps a spraying gun, and a spraying program is operated to achieve automatic spraying of paint; automatic control of the viscosity of the coating is realized through the automatic viscosity controller of the coating; the flow controller is used for realizing stable control and output of the coating discharge amount; a terahertz automatic thickness measuring system is used for measuring the thickness of a wet film and the thickness of a dry film of the coating; the whole programmed control of the spraying robot, the terahertz automatic thickness measuring system, the rotary table, the guide rail, the flow and the thickness measuring system is controlled through the industrial personal computer, the automatic spraying device is suitable for automatic spraying of the planetary detector back cover structure, and the thickness error is smaller than or equal to + / -3%.

Description

Technical Field

[0001] The present invention relates to an automatic coating device and method for variable thickness ultra-low density heat-resistant coatings, which can be applied to the heat protection of the outer surface of the back cover structure of a space probe, and belongs to the technical field of surface engineering heat-resistant coatings. Background Art

[0002] The entry cabin structure of a planetary probe lander is generally divided into a back cover structure and a large bottom structure, which mainly plays the role of protecting the lander during flight, orbiting, and landing. When a planetary lander enters the planetary atmosphere, the flight speed can reach more than 10Ma, and the surface of the probe is severely aerodynamically heated. The thermal protection coating has the advantages of low density, simple construction process, and high thermal protection efficiency. It is the preferred material solution for the low heat flow part of the probe. Due to the limited carrying capacity of the rocket, the lightweight requirements of the planetary probe are very stringent. Through technical research, a room temperature curing, large thickness, ultra-low density, high toughness silicone rubber thermal protection coating has been developed for the outer surface of the back cover structure of the planetary probe. However, due to the different degrees of thermal scouring at different positions of the aircraft during flight, the coating thickness requirements at different positions are different. At the same time, the lower end diameter of the typical back cover structure reaches 3.0~3.4m, and the upper end diameter is only 0.5~0.6m. The back cover structure product size is large, the unit cost is high, and the density of the spray coating is only 0.24~0.28g / cm 3 The following difficulties exist during spraying: (1) The different coating thicknesses at different positions increase the difficulty of spraying. The thickness gradually changes from 9 to 10 mm at the upper end to 5 to 6 mm at the lower end. The coating is thickened in some parts. The upper and lower diameters of the workpiece are very different. The different linear speeds during rotation lead to different coating thicknesses. (2) The workpiece is large in size, and the spraying position of the spray robot arm needs to be adjusted. (3) The rotating table, the spray robot arm, and the guide rail position and the spraying program need to be controlled in a linked manner, otherwise fine spraying will not be possible. (4) The viscosity of the paint needs to be stably controlled. (5) The flow rate of ultra-low density paint, i.e. the discharge volume, needs to be stably controlled. When spraying at different positions, the discharge volume needs to be adjusted to ensure that the spray thickness at different positions is controlled. (6) The paint flow rate needs to be deeply bound to the spraying program, and the flow rate must be switched instantly during the spraying process. (7) The wet film thickness and dry film thickness measurement technology should be used after the paint is sprayed.

[0003] In view of the above problems, an automatic coating method for ultra-low density thermal protection coating with variable thickness is established to realize the automatic spraying of ultra-low density thermal protection coating with variable thickness on the back cover structure. Summary of the invention

[0004] The purpose of the present invention is to overcome the above-mentioned shortcomings of the prior art and to provide an automatic coating device and method for variable thickness ultra-low density thermal protection coatings, which can be applied to the automatic spraying of the back cover structure of a planetary probe, and the thickness error is ≤±3%.

[0005] The above-mentioned purpose of the present invention is mainly achieved through the following technical solutions:

[0006] An automatic coating equipment for variable thickness ultra-low density heat-resistant coating, comprising:

[0007] The spraying robot receives the spraying instruction and the edited spraying program sent by the industrial computer, and according to the spraying program, holds the spray gun to spray the paint on the workpiece to be sprayed;

[0008] Spraying programming system, which programs the spraying program and sends it to the industrial computer;

[0009] The servo rotating table is used to place the workpiece to be sprayed and drives the workpiece to be sprayed to rotate under the control of the industrial computer;

[0010] The coating viscosity automatic controller receives the viscosity requirement instruction sent by the industrial computer, adds the solvent in the coating according to the viscosity requirement instruction, and adjusts the coating viscosity to the viscosity requirement value;

[0011] The flow controller receives the instruction from the industrial computer, delivers the paint according to the paint delivery flow required by the industrial computer, and feeds back the measured paint flow value to the industrial computer;

[0012] The terahertz automatic thickness measurement system includes an automatic thickness measurement robot and a terahertz thickness measurement device, wherein the terahertz thickness measurement device is installed on the automatic thickness measurement robot. After receiving the instruction from the industrial control computer, the automatic thickness measurement robot drives the terahertz thickness measurement device to the designated position. The terahertz thickness measurement device measures the coating thickness of the workpiece after spraying and sends the measured thickness value to the industrial control computer.

[0013] The industrial computer sends control instructions to and controls the spraying robot, servo rotary table, paint viscosity automatic controller, flow controller and terahertz automatic thickness measurement system.

[0014] In the above-mentioned variable thickness ultra-low density thermal protection coating automatic coating equipment, the paint viscosity automatic controller forms a reflux with the paint storage tank. The paint viscosity automatic controller includes a viscosity measuring instrument and a solvent storage device. The viscosity measuring instrument receives the viscosity requirement instruction sent by the industrial computer and measures the viscosity of the paint in real time. If the paint viscosity does not reach the required viscosity value, the solvent storage device is controlled to add solvent to the paint circulation pipeline until the real-time viscosity of the paint measured by the paint viscosity measuring instrument reaches the required value.

[0015] The above-mentioned variable thickness ultra-low density thermal protection coating automatic coating equipment also includes an automatic transfer vehicle, which receives instructions sent by the industrial computer, places the workpiece to be sprayed on the servo rotating table, and transfers the workpiece with the required coating thickness to the designated position.

[0016] The above-mentioned variable thickness ultra-low density thermal protection coating automatic coating equipment also includes a robot guide rail, which is used to install a spraying robot and an automatic thickness measuring robot, and transport the spraying robot and the automatic thickness measuring robot to a designated location under the control of an industrial computer.

[0017] In the above-mentioned variable thickness ultra-low density thermal protection coating automatic coating equipment, the flow controller is a volumetric flow metering device, which controls the coating flow through an electrically driven metering pump, does not destroy the hollow microspheres in the thermal protection coating component, and will not be blocked by ground fibers.

[0018] In the above-mentioned variable thickness ultra-low density thermal protection coating automatic coating equipment, the spray robot and the flow controller are connected through the ADC digital-to-analog converter, and the analog signal output by the robot is converted into a digital quantity and output online as the flow input of the spraying equipment, so that the robot spraying program can control the automatic spraying flow and achieve rapid switching.

[0019] In the above-mentioned variable thickness ultra-low density heat-resistant coating automatic coating equipment, the density of the variable thickness ultra-low density heat-resistant coating is 0.24-0.28 g / cm 3 Through real-time switching of the spray flow rate and changes in the workpiece rotation speed, the coating thickness at different positions changes from 0.15mm to 0.5mm after a single spraying, and the overall coating thickness of the workpiece gradually changes from 9-10mm to 5-6mm.

[0020] In the above-mentioned variable thickness ultra-low density thermal protection coating automatic coating equipment, the automatic thickness measuring robot of the terahertz automatic thickness measuring system clamps the terahertz thickness measuring equipment close to the coating at a distance of 3 to 5 cm and emits terahertz waves. The terahertz waves are reflected on both the coating surface and the substrate surface to generate a waveform graph. The wet film thickness or dry film thickness of the coating is obtained by measuring the position difference of the reflected waves.

[0021] In the above-mentioned variable thickness ultra-low density thermal protection coating automatic coating equipment, when the terahertz automatic thickness measurement system measures that the coating wet film thickness does not meet the requirements, it will feedback to the industrial computer, and the industrial computer will control the spraying robot to re-spray the workpiece until the requirements are met.

[0022] In the above-mentioned variable thickness ultra-low density thermal protection coating automatic coating equipment, the servo rotary table and the robot guide rail are controlled by the PLC of the industrial computer to achieve linkage control with the spraying robot, and the spraying speed, the robot's running speed and position on the guide rail are edited in the spraying programming system to achieve full automatic control of the servo rotary table speed, the spraying robot speed and position, the spraying trajectory, and the switch gun, thereby realizing automatic coating of variable thickness ultra-low density thermal protection coating.

[0023] In the above-mentioned variable thickness ultra-low density thermal protection coating automatic coating equipment, the automatic transfer vehicle is an AGV automatic transfer vehicle, which realizes automatic path planning through laser navigation.

[0024] In the above-mentioned variable thickness ultra-low density thermal protection coating automatic coating equipment, the workpiece to be sprayed is used for a planetary exploration lander system, with a lower end diameter of 3.0 to 3.4 m and an upper end diameter of 0.5 to 0.6 m.

[0025] An automatic coating method for variable thickness ultra-low density heat-resistant coating, applied to the above coating equipment, comprising:

[0026] The paint viscosity automatic controller receives the viscosity requirement instruction sent by the industrial computer, adds solvent in the paint according to the viscosity requirement instruction, and adjusts the paint viscosity to the viscosity requirement value;

[0027] The flow controller receives the instruction from the industrial computer, delivers the paint according to the paint delivery flow required by the industrial computer, and feeds back the measured paint flow value to the industrial computer;

[0028] The spray programming system programs the spray program and sends it to the industrial computer, which sends the spray instruction and the edited spray program to the spray robot;

[0029] The spraying robot is programmed according to the spraying program, and moves to a specified position driven by the robot guide rail, and clamps the spray gun to spray the paint on the workpiece to be sprayed; the servo rotary table drives the workpiece to be sprayed to rotate under the control of the industrial computer;

[0030] After receiving the command from the industrial computer, the automatic thickness measuring robot brings the terahertz thickness measuring device to the designated position under the drive of the robot guide rail. The terahertz thickness measuring device measures the coating thickness of the workpiece after spraying and sends the measured thickness value to the industrial computer.

[0031] The automatic transfer vehicle receives instructions from the industrial computer and transfers the workpieces with coating thickness reaching the required level to the designated location.

[0032] Compared with the prior art, the present invention has at least the following beneficial effects:

[0033] (1) The automatic coating equipment provided by the embodiment of the present invention includes a spraying robot, a spraying programming system, a servo rotating table, a paint viscosity automatic controller, a flow controller, a terahertz automatic thickness measurement system, an industrial computer, etc. The workpiece is placed on the servo rotating table, and the spraying program is programmed for the workpiece through the spraying programming system; the spraying robot clamps the spray gun, sets the spraying trajectory in the spraying program, and runs the spraying program to realize automatic spraying of the paint; the automatic viscosity controller of the paint realizes automatic control of the viscosity of the paint; the flow controller realizes stable output of the paint discharge amount; the terahertz automatic thickness measurement system is used to measure the wet film thickness of the coating, and the re-spraying is performed according to the wet film thickness measurement result. After the coating is cured, the terahertz automatic thickness measurement system is used to measure the dry film thickness of the coating; the industrial computer is used to control the overall programmed control of the spraying robot, the terahertz automatic thickness measurement system, the servo rotating table, the flow rate, and the thickness measurement system. The present invention can be applied to the automatic spraying of the back cover structure of a planetary probe, and the thickness error is ≤±3%;

[0034] (2) In the embodiment of the present invention, the preferred spray programming system uses PLC to control the servo rotary table and the robot guide rail to achieve linkage control with the robot, realize full automatic control of the rotary table speed, the speed and position of the spray robot, the spray trajectory, and the switch gun in the spraying program, and realize automatic coating of variable thickness ultra-low density heat-resistant coating;

[0035] (3) In the embodiment of the present invention, the preferred coating flow controller needs to use a volumetric flow metering device, which does not damage the hollow microspheres in the ultra-low density heat-resistant coating component and will not be blocked by ground fibers. The robot and the flow controller need to be connected through an ADC digital-to-analog converter, and the analog signal output by the robot is converted into a digital signal and output online as the flow input of the spraying equipment, so that the robot spraying program can automatically control the spraying flow and achieve fast and instant switching;

[0036] (4) In the preferred embodiment of the present invention, the terahertz automatic thickness measurement system generates a waveform through the reflection of terahertz on the coating surface and the substrate surface, and determines the coating thickness by measuring the position difference of the reflected wave. This method does not require contact with the coating and can realize the thickness measurement of the wet film and dry film of the coating. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 This is a diagram of the spraying process of the ultra-low density coating on the detector back cover structure in an embodiment of the present invention;

[0038] Figure 2 It is a schematic diagram of the automatic coating method of variable thickness ultra-low density heat-resistant coating in an embodiment of the present invention;

[0039] Figure 3 This is a typical waveform diagram of terahertz thickness measurement in an embodiment of the present invention. DETAILED DESCRIPTION

[0040] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments:

[0041] like Figure 1 , 2 As shown, the variable thickness ultra-low density heat-resistant coating automatic coating equipment of the present invention includes a spraying robot 1, a spraying programming system 2, a servo rotating table 3, a coating viscosity automatic controller 4, a flow controller 5, a terahertz automatic thickness measurement system 6, an industrial computer 7, an automatic transfer vehicle 8 and a robot guide rail 9.

[0042] The spraying robot 1 receives the spraying instruction and the edited spraying program sent by the industrial computer, and according to the edited spraying program, it clamps the spray gun to spray the paint on the workpiece to be sprayed.

[0043] The spraying programming system 2 programs the spraying program and sends it to the industrial computer.

[0044] The servo rotating table 3 is used to place the workpiece to be sprayed, and drives the workpiece to be sprayed to rotate under the control of the industrial computer.

[0045] The paint viscosity automatic controller 4 forms a reflux with the paint storage tank. The paint viscosity automatic controller includes a viscosity measuring instrument and a solvent storage device. The viscosity measuring instrument receives the viscosity requirement instruction sent by the industrial computer. The viscosity measuring instrument measures the viscosity of the paint in real time. If the viscosity of the paint does not reach the required viscosity value, the viscosity automatic controller controls the solvent storage device to add solvent to the paint circulation pipeline until the real-time viscosity of the paint measured by the paint viscosity measuring instrument reaches the required value.

[0046] The flow controller 5 receives the instructions of the industrial computer, controls the flow of the paint in the paint delivery pipeline, and sends the measured value to the industrial computer; the flow controller 5 preferably uses a volumetric flow metering device, controls the flow of the paint through an electrically driven metering pump, does not damage the hollow microspheres in the ultra-low density heat-resistant paint component, and will not be blocked by ground fibers. The spray robot 1 and the flow controller 5 are connected through an ADC digital-to-analog converter, and the analog signal output by the robot is converted into a digital quantity and output online as the flow input of the spraying equipment, so that the robot spraying program can automatically control the spraying flow and achieve rapid switching.

[0047] The terahertz automatic thickness measurement system 6 includes an automatic thickness measurement robot and a terahertz thickness measurement device, wherein the terahertz thickness measurement device is installed on the automatic thickness measurement robot. After receiving the instruction from the industrial computer, the automatic thickness measurement robot drives the terahertz thickness measurement device to the specified position. The terahertz thickness measurement device measures the coating thickness of the workpiece after spraying and sends the measured thickness value to the industrial computer.

[0048] The wet film thickness and dry film thickness of the paint after spraying are measured using the terahertz automatic thickness measurement system 6. The terahertz is reflected on the coating surface and the substrate surface to generate a waveform diagram. The coating thickness is determined by measuring the position difference of the reflected wave. This method does not require contact with the coating and can measure the thickness of the wet film and dry film of the coating. The terahertz detector is clamped by a robot. The program sets that when the detector is about 3 to 5 cm close to the coating, the terahertz wave is emitted, and a waveform diagram appears on the industrial computer. The wet film thickness or dry film thickness of the coating is obtained by testing. When the terahertz automatic thickness measurement system 6 measures that the wet film thickness of the coating does not meet the requirements, it is fed back to the industrial computer, and the industrial computer controls the spraying robot 1 to spray the workpiece to be sprayed until the requirements are met.

[0049] The automatic transfer vehicle 8 receives the instruction sent by the industrial computer, places the workpiece to be sprayed on the servo rotary table 3, and transfers the workpiece with the required coating thickness to the designated position. The automatic transfer vehicle is preferably an AGV automatic transfer vehicle, which realizes automatic path planning through laser navigation.

[0050] The robot guide rail 9 is used to install the spraying robot 1 and the terahertz automatic thickness measuring robot, and transport the spraying robot 1 and the terahertz automatic thickness measuring robot to a designated location under the control of the industrial computer.

[0051] The servo rotating table 3 and the robot guide rail 9 are controlled by the PLC of the industrial computer to achieve linkage control with the spraying robot 1, and the spraying speed, the running speed and the position of the robot on the guide rail are edited in the spraying programming system 2 to achieve full automatic control of the servo rotating table 3 speed, the speed and position of the spraying robot 1, the spraying trajectory, and the switch gun, thereby realizing automatic coating of variable thickness ultra-low density heat-resistant coatings.

[0052] The industrial computer 7 sends control instructions to the spraying robot 1, the servo rotary table 3, the paint viscosity automatic controller 4, the flow controller 5 and the terahertz automatic thickness measurement system 6 and controls them. The industrial computer controls the entire spraying process through the central control system, including automatic transportation, spraying program compilation, viscosity automatic control, flow control, automatic thickness measurement and recording.

[0053] The present invention can be applied to the automatic spraying of large-thickness ultra-low-density high-toughness silicone rubber heat-resistant paint on the outer surface of the back cover structure of a planetary probe.

[0054] Example

[0055] The ultra-low-density heat-resistant coating with variable thickness is sprayed on the outer surface of the back cover structure using the automatic coating method. The diameter of the lower end of the back cover structure is about 3.4m, and the diameter of the upper end is about 0.6m. The workpiece is divided into two parts, the lower part is conical, and the upper part is arc-conical. The ultra-low-density coating is a silicone rubber-based heat-resistant coating, with a large amount of hollow microspheres and appropriate fiber fillers added, and the density is about 0.24-0.28g / cm 3.

[0056] The servo rotary table 3 and the robot guide rail 9 are controlled by the industrial computer through the PLC to realize the linkage control with the spraying robot 1, and the spraying speed, the running speed and the position of the robot 1 on the guide rail 9 are edited in the spraying program through the spraying programming system 2. The three-dimensional image of the workpiece is imported into the spraying programming system, and the running trajectory of the spray gun, that is, the running speed along the workpiece generatrix is ​​adjusted in the spraying programming system 2, and the rotation speed of the workpiece on the servo rotary table is designed in coordination, so that the rotation speed matches the running position of the spray gun, and the error of the running linear speed of the workpiece at the spraying position is ensured to be less than 10%. At the same time, the position of the spraying robot 1 on the guide rail is adjusted to ensure that the spraying robot 1 can spray without interruption throughout the whole process.

[0057] The spraying program can be divided into two parts, one is the lower conical spraying program, and the other is the upper arc conical spraying program. The two sections can set different spraying line speeds, and set different spraying flow rates to match the spraying line speeds. The paint flow controller uses a volumetric flow metering device, which does not destroy the hollow microspheres in the ultra-low density heat-resistant paint component, and will not be blocked by ground fibers. The robot and the flow controller are connected through an ADC digital-to-analog converter, and the analog signal output by the robot is converted into a digital quantity and output online as the flow input of the spraying equipment, so that the robot 1 spraying program can automatically control the spraying flow and realize fast and instant switching, and the spraying flow can be controlled and quickly switched through the spraying program.

[0058] The spraying program including the spraying trajectory, the position and running speed of the spraying robot 1, the rotating speed of the turntable, the spraying flow rate, and the spraying switch information is edited and confirmed, and after passing the simulation operation test, it is saved for use.

[0059] The robot holds the terahertz detector, sets a program to control the position of the detector, emits terahertz light waves when it is about 3 to 5 cm away from the surface to be tested, and the robot returns with the detector after the test. The test program is saved for later use.

[0060] After the workpiece arrives, use a crane to lift the workpiece onto the AGV automatic transport vehicle 8. Through the program control on the industrial computer 7, the AGV automatic transport vehicle 8 transports the workpiece to the servo rotary table 3; after the paint is prepared, the paint viscosity is controlled by the paint viscosity automatic controller 4; the spraying program is automatically run by the industrial computer 7, and the spraying program controls the running speed and position of the robot arm on the guide rail, the speed of the servo rotary table, the spraying trajectory, the spray switch gun position, the spraying flow rate and other related parameters to achieve automatic spraying of the workpiece. After running the spraying program for multiple times, run the terahertz automatic detection robot thickness measurement program to detect the wet film thickness, and perform additional spraying or stop according to the test results. After the coating is cured, test again to confirm that the thickness is qualified. The industrial computer 7 controls the AGV automatic transport vehicle 8 to automatically transport the sprayed workpiece to complete the spraying.

[0061] The industrial computer 7 controls the entire spraying process through the central control system, including automatic transportation, spraying program compilation, viscosity automatic control, flow control, automatic thickness measurement and recording.

[0062] The above description is only the best specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

[0063] The contents not described in detail in the specification of the present invention belong to the common knowledge of the professionals in this field.

Claims

1. An automatic coating equipment for variable thickness ultra-low density heat-resistant coating, characterized in that: include: The spraying robot (1) receives the spraying instruction and the edited spraying program sent by the industrial computer, and according to the spraying program, holds the spray gun to spray the paint on the workpiece to be sprayed; A spraying programming system (2) is used to program the spraying program and send it to the industrial computer; A servo rotating table (3) is used to place the workpiece to be sprayed and drive the workpiece to be sprayed to rotate under the control of the industrial computer; The coating viscosity automatic controller (4) receives the viscosity requirement instruction sent by the industrial computer, adds solvent to the coating according to the viscosity requirement instruction, and adjusts the coating viscosity to the viscosity requirement value; A flow controller (5) receives instructions from the industrial computer, delivers the paint according to the paint delivery flow rate required by the industrial computer, and feeds back the measured paint flow rate value to the industrial computer; A terahertz automatic thickness measurement system (6), comprising an automatic thickness measurement robot and a terahertz thickness measurement device, wherein the terahertz thickness measurement device is installed on the automatic thickness measurement robot, and after receiving an instruction from the industrial control computer, the automatic thickness measurement robot drives the terahertz thickness measurement device to a designated position, and the terahertz thickness measurement device measures the coating thickness of the workpiece after spraying, and sends the measured thickness value to the industrial control computer; The industrial computer (7) sends control instructions to the spraying robot (1), the servo rotary table (3), the paint viscosity automatic controller (4), the flow controller (5) and the terahertz automatic thickness measurement system (6) to perform control.

2. The variable thickness ultra-low density heat-resistant coating automatic coating equipment according to claim 1 is characterized in that: The paint viscosity automatic controller (4) forms a reflux with the paint storage tank. The paint viscosity automatic controller comprises a viscosity measuring instrument and a solvent storage device. The viscosity measuring instrument receives a viscosity requirement instruction sent by the industrial computer and measures the viscosity of the paint in real time. If the viscosity of the paint does not reach the required viscosity value, the solvent storage device is controlled to add solvent to the paint circulation pipeline until the real-time viscosity of the paint measured by the paint viscosity measuring instrument reaches the required value.

3. The variable thickness ultra-low density heat-resistant coating automatic coating equipment according to claim 1 is characterized in that: It also includes an automatic transfer vehicle (8), which receives instructions sent by the industrial computer, places the workpiece to be sprayed on the servo rotating table (3), and transfers the workpiece with a coating thickness that meets the requirements to a designated position.

4. The variable thickness ultra-low density heat-resistant coating automatic coating equipment according to claim 1 is characterized in that: It also comprises a robot guide rail (9), wherein the robot guide rail (9) is used to install the spraying robot (1) and the automatic thickness measuring robot, and to transport the spraying robot (1) and the automatic thickness measuring robot to a designated position under the control of the industrial computer.

5. The variable thickness ultra-low density heat-resistant coating automatic coating equipment according to claim 1 is characterized in that: The flow controller (5) is a volumetric flow metering device, which controls the coating flow rate through an electrically driven metering pump, does not damage the hollow microspheres in the heat-resistant coating component, and will not be blocked by ground fibers.

6. The variable thickness ultra-low density heat-resistant coating automatic coating equipment according to claim 1 is characterized in that: The spraying robot (1) and the flow controller (5) are connected via an ADC digital-to-analog converter, and the analog signal output by the robot is converted into a digital signal and output online as the flow input of the spraying equipment, thereby realizing automatic spraying flow control by the robot spraying program and achieving rapid switching.

7. The variable thickness ultra-low density heat-resistant coating automatic coating equipment according to claim 1 is characterized in that: The density of the variable thickness ultra-low density heat-resistant coating is 0.24-0.28 g / cm 3 Through real-time switching of the spray flow rate and changes in the workpiece rotation speed, the coating thickness at different positions changes from 0.15mm to 0.5mm after a single spraying, and the overall coating thickness of the workpiece gradually changes from 9-10mm to 5-6mm.

8. The variable thickness ultra-low density heat-resistant coating automatic coating equipment according to claim 1 is characterized in that: The automatic thickness measuring robot of the terahertz automatic thickness measuring system (6) holds the terahertz thickness measuring device close to the coating at a distance of 3 to 5 cm, and emits terahertz waves. The terahertz waves are reflected on both the coating surface and the substrate surface to generate a waveform diagram. The wet film thickness or dry film thickness of the coating is obtained by measuring the position difference of the reflected waves.

9. The variable thickness ultra-low density heat-resistant coating automatic coating equipment according to claim 8 is characterized in that: When the terahertz automatic thickness measurement system (6) measures that the coating wet film thickness does not meet the requirements, feedback is sent to the industrial control computer, and the industrial control computer controls the spraying robot (1) to re-spray the workpiece to be sprayed until the requirements are met.

10. The variable thickness ultra-low density heat-resistant coating automatic coating equipment according to claim 4 is characterized in that: The servo rotary table (3) and the robot guide rail (9) are controlled by the PLC of the industrial computer to realize linkage control with the spraying robot (1), and the spraying speed, the running speed and the position of the robot on the guide rail are edited in the spraying programming system (2), so as to realize full automatic control of the speed of the servo rotary table (3), the speed and position of the spraying robot (1), the spraying trajectory, and the switch gun, thereby realizing automatic coating of variable thickness ultra-low density heat-resistant coating.

11. The variable thickness ultra-low density heat-resistant coating automatic coating equipment according to claim 3 is characterized in that: The automatic transfer vehicle (8) is an AGV automatic transfer vehicle, which realizes automatic path planning through laser navigation.

12. The variable thickness ultra-low density heat-resistant coating automatic coating equipment according to claim 1 is characterized in that: The workpiece to be sprayed is used in a planetary exploration lander system, with a lower end diameter of 3.0 to 3.4 m and an upper end diameter of 0.5 to 0.6 m.

13. A method for automatically applying a variable thickness ultra-low density heat-resistant coating, characterized in that: The coating equipment according to any one of claims 1 to 12 comprises: The coating viscosity automatic controller (4) receives the viscosity requirement instruction sent by the industrial computer, adds solvent in the coating according to the viscosity requirement instruction, and adjusts the coating viscosity to the viscosity requirement value; The flow controller (5) receives the instruction from the industrial computer, conveys the paint according to the paint conveying flow rate required by the industrial computer, and feeds back the measured paint flow rate value to the industrial computer; The spraying programming system (2) programs the spraying program and sends it to the industrial computer, and the industrial computer sends the spraying instruction and the edited spraying program to the spraying robot (1); The spraying robot (1) is programmed according to the spraying program, moves to a specified position driven by the robot guide rail (9), and clamps the spray gun to spray the paint on the workpiece to be sprayed; the servo rotary table (3) drives the workpiece to be sprayed to rotate under the control of the industrial computer; After receiving the instruction from the industrial computer, the automatic thickness measuring robot brings the terahertz thickness measuring device to the designated position under the drive of the robot guide rail (9), and the terahertz thickness measuring device measures the coating thickness of the workpiece after spraying, and sends the measured thickness value to the industrial computer; The automatic transfer vehicle (8) receives the instruction sent by the industrial computer and transfers the workpiece whose coating thickness reaches the required level to the designated location.

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