Temperature control assembly for a space robot joint

Abstract

The application relates to the field of aerospace technology, in particular to a temperature control device for a space mechanical arm joint, which comprises a heating sheet, a heat dissipation surface, a temperature measuring sensor, a heat pipe, a graphite film and heat insulation material, wherein the heating sheet and the heat dissipation surface are arranged on the outer wall of an electric box shell of the space mechanical arm joint and the outer wall of a joint shell of the space mechanical arm joint, and are arranged on the outer wall of the joint shell except the side wall of the joint shell where a joint female end of the space mechanical arm joint is located; the temperature measuring sensor is installed on the outer wall of the electric box shell; the heat pipe is installed on the outer walls of the axial two ends of the joint shell through screws; the graphite film is fixed on the inner wall of the joint shell through heat-conducting glue; the heat insulation material is wrapped on the outer walls of the joint shell and the electric box shell except the heat dissipation surface, and the heating sheet, the temperature measuring sensor and the heat pipe are all wrapped in the heat insulation material. The application has the advantages of high heat dissipation capacity and fast heat dissipation speed, and solves the problems of difficult heat dissipation and poor temperature distribution uniformity of the space mechanical arm joint during continuous work.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of aerospace technology, and in particular to a temperature control device for a space manipulator joint. BACKGROUND

[0002] The space manipulator is mainly responsible for on-orbit tasks such as cargo handling and astronaut extravehicular activities, and is usually directly exposed to the cold and dark space environment. The space manipulator joint is the core executive component of the space manipulator. In order to keep the joint within a reasonable temperature range, effective thermal design is required. The thermal design of the space manipulator joint needs to consider the difficulties of on-orbit attitude changes, large external heat flow, large internal heat source power consumption, and serious heat leakage at the locking point. Therefore, necessary and efficient temperature control measures need to be taken.

[0003] Due to the irregular shape of the joint shell of the space manipulator, it is difficult to control the design position of the heat dissipation surface. Therefore, the existing temperature control device of the space manipulator only designs one heat dissipation surface, which causes the heat generated during the operation of the space manipulator joint to be unable to be effectively dissipated when the sun shines on the joint outer wall where the heat dissipation surface is located. This will cause the overall temperature of the space manipulator joint to rise, causing the motor and other moving parts to malfunction. At the same time, it also causes poor temperature uniformity of the joint shell and other components. SUMMARY

[0004] The present application provides a temperature control device for a space manipulator joint to solve the problem of poor temperature distribution uniformity and difficulty in heat dissipation during continuous operation of the space manipulator joint on orbit. The temperature control device ensures that the space manipulator joint can effectively dissipate heat during long-term on-orbit operation and has uniform temperature distribution.

[0005] The temperature control device for a space manipulator joint provided by the present application includes a heating sheet, a heat dissipation surface, a temperature sensor, a heat pipe, a graphite film, and a thermal insulation material, wherein,

[0006] The heating sheet and the heat dissipation surface are arranged on the outer wall of the electric box shell of the space manipulator joint and the outer wall of the joint shell of the space manipulator joint, except for the side wall of the joint shell where the joint female end is located. The temperature sensor is installed on the outer wall of the electric box shell. The heat pipe is installed on the outer wall of the axial ends of the joint shell through screws. The graphite film is fixed on the inner wall of the joint shell through thermal conductive glue. The thermal insulation material is wrapped on the outer walls of the joint shell and the electric box shell, except for the heat dissipation surface, and all of the heating sheet, the temperature sensor, and the heat pipe are wrapped therein.

[0007] Preferably, the temperature control device of the space robot joint further comprises a control unit electrically connected with the heating sheet and the temperature sensor, the control unit receives temperature information collected by the temperature sensor, and judges whether to send a control signal according to the temperature information to control the heating sheet to warm the joint shell and the electric box shell.

[0008] Preferably, the heat dissipation direction of the heat dissipation surface includes and is not less than three-dimensional direction.

[0009] Preferably, the installation position of the temperature sensor is kept away from the heating sheet and the heat dissipation surface to ensure that the normal work of the temperature sensor is not affected by the heating sheet and the heat dissipation surface.

[0010] Compared with the prior art, the application can achieve the following beneficial effects: the application opens the heat dissipation surface in not less than three-dimensional direction on the joint shell and the electric box shell of the space robot joint, so that when the space robot joint is exposed to the sun in a certain direction, the heat dissipation surface in other directions can still effectively dissipate heat; the graphite film is fixedly connected to the inner wall of the joint shell of the space robot joint through the heat-conducting glue, and the annular heat pipe is installed on the outer wall of the two axial ends through the screw, so that the heat transfer efficiency of the joint shell of the space robot joint is improved, the temperature distribution uniformity of the joint of the space robot is optimized, and the joint of the space robot has stable working conditions. BRIEF DESCRIPTION OF DRAWINGS

[0011] Figure 1 is a cross-sectional structure schematic view of the temperature control device of the space robot joint according to the embodiment of the application.

[0012] Figure 2 is a side structure schematic view of the temperature control device of the space robot joint according to the embodiment of the application.

[0013] The drawings show: the temperature sensor 1, the graphite film 2, the heat insulation material 3, the heat pipe 4, the joint shell 5, the heat-conducting glue 6, the heat dissipation surface 7, the heating sheet 8, the electric box shell 9, the joint female end 10, the joint male end 11 and the end cover 12. DETAILED DESCRIPTION

[0014] Hereinafter, embodiments of the present application will be described with reference to the accompanying drawings. In the following description, the same modules are denoted by the same reference numerals. In the case of the same reference numerals, their names and functions are also the same. Therefore, detailed descriptions thereof will not be repeated.

[0015] In order to make the purpose, technical scheme and advantages of the present application more clear, the present application will be further described in detail below with reference to the drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application, and do not constitute a limitation on the present application.

[0016] Figure 1The sectional structure of the temperature control device of the space mechanical arm joint is shown; Figure 2 The side structure of the temperature control device of the space mechanical arm joint is shown.

[0017] As Figures 1-2 shown, the temperature control device of the space mechanical arm joint comprises a heating sheet 8, a heat dissipation surface 7, a temperature sensor 1, a heat pipe 4, a graphite film 2 and a thermal insulation material 3, wherein,

[0018] The heating sheet 8 and the heat dissipation surface 7 are arranged on the outer wall of an electric box shell 9 of the space mechanical arm joint and the outer wall of a joint shell 5 of the space mechanical arm joint, and are arranged on the outer wall of the joint shell 5 except the side wall of the joint shell 5 where a joint female end 10 is located; the temperature sensor 1 is installed on the outer wall of the electric box shell 9; the heat pipe 4 is installed on the outer wall of the joint shell 5 at both axial ends through screws; the graphite film 2 is fixed on the inner wall of the joint shell 5 through a heat-conducting glue 6; the thermal insulation material 3 is wrapped on the outer wall of the joint shell 5 and the electric box shell 9 except the heat dissipation surface 7, and wraps the heating sheet 8, the temperature sensor 1 and the heat pipe 4.

[0019] The temperature control device of the space mechanical arm joint further comprises a control unit, the control unit is electrically connected with the heating sheet 8 and the temperature sensor 1, the control unit receives temperature information collected by the temperature sensor 1, and judges whether to send a control signal according to the temperature information, and controls the heating sheet 8 to heat the joint shell 5 and the electric box shell 9. The number and power of the heating sheet 8 need to be designed according to the temperature index requirements of each component of the joint. The temperature index generally makes certain requirements for motors, electric boxes, motion mechanisms and the like, so as to ensure that the joint can stably work in orbit at a reasonable environmental temperature. The temperature index range of each component of the joint is shown in the following table:

[0020] Reliability analysis of the heating sheet 8:

[0021] Serial number Component name Operating temperature (°C) 1 Joint housing 5 -30～+50 2 Joint electrical box 9 -30～+50 3 Motor -30～+80

[0022] The heating sheet 8 adopts H-125 or H-150 type polyimide film type heating sheet 8, and adopts two control modes of remote heating and self-control heating.

[0023] a) The polyimide film type heating sheet 8 adopted has been used in a large number of satellites in China, and has been in orbit for nearly 10 years at present, without any failure signs;

[0024] b) The pasting and lead welding of the heating sheet 8 adopt corresponding reinforcement measures, such as silicon rubber is applied to the lead of the heating sheet 8 close to the welding point, to strengthen the fixation between the root of the lead and the mounting surface.

[0025] The heat dissipation surface 7 can be provided in the form of spraying white paint or the like high-emission low-absorption pigment, the absorption rate of white paint to solar radiation is about 0.12-0.16, the infrared radiation absorption rate is 0.90-0.95, the heat dissipation direction of the heat dissipation surface 7 includes and is not less than three-dimensional direction, the three-dimensional direction is +X, -X, +Y, -Y, +Z, -Z direction of the space rectangular coordinate system, since the joint shell 5 is a structure similar to a cylinder, the heat dissipation direction of the heat dissipation surface 7 can be set in other directions except the three-dimensional direction according to the heat dissipation requirement and structural characteristics of the space manipulator joint.

[0026] The installation position of the temperature measuring sensor 1 is kept away from the heating sheet 8 and the heat dissipation surface 7, so that the normal work of the temperature measuring sensor 1 is not affected by the heating sheet 8 and the heat dissipation surface 7. The temperature measuring sensor 1 includes a temperature relay or a thermistor.

[0027] Reliability analysis of the thermistor:

[0028] a) The MF501 type thermistor used has multiple successful space application experiences;

[0029] b) The thermistor with 2% precision is used for ground unit test, and the thermistor with 1% precision is used for initial sample identification and normal sample flight products.

[0030] The axial two ends of the joint shell 5 are respectively a joint male end 11 and an end cover 12, the heat pipe 4 is fixed at the joint of the joint male end 11 and the joint shell body and the joint of the end cover 12 and the joint shell body, which further maintains the uniformity of the circumferential temperature distribution of the axial two ends of the joint shell 5.

[0031] Since the material of the space manipulator joint shell 5 is generally titanium alloy with a thermal conductivity of 5.44 W / (m·K), and the thermal conductivity of the graphite film 2 is 1200 W / (m·K), the setting of the graphite film 2 can increase the heat transfer efficiency of the space manipulator joint shell 5 by 3-5 times. This not only effectively improves the uniformity of the space manipulator joint shell 5, but also provides a stable working environment for the moving parts inside the space manipulator joint.

[0032] In addition, in order to prevent heat leakage of other components of the space manipulator joint, the joint male end 11, the end cover 12 and the joint female end 10 are all coated with the heat insulation material 3. Since the surface structure of the joint male end 11, the end cover 12 and the joint female end 10 is irregular, the coating of the heat insulation material 3 needs to be designed according to the structure of the joint male end 11, the end cover 12 and the joint female end 10. The coating of the joint male end 11, the end cover 12 and the joint female end 10 belongs to the prior art, which will not be introduced here.

[0033] Reliability analysis of the heat insulation material 3:

[0034] a) The heat insulation material 3 used and the fixing mode (nylon fastener type) of the heat insulation material 3 have been used on satellites at home and abroad and have been verified by flight;

[0035] b) The heat insulation material 3 used has good performance, and the surface film thereof is selected from an outer-use type anti-atomic oxygen cloth, can resist cold-heat alternation of-180~+100C, and has high stability in a space radiation environment. The background radiation energy of the universe space is about 10^(-5)W / m 2 , which is equivalent to the absolute black body radiation of 4K. Meanwhile, the geometric size of the satellite body is negligible compared with the universe space, and the energy radiated by the satellite body itself all enters the universe space. When carrying out thermal design and thermal analysis, the environmental temperature is generally set to 4K.

[0036] When the space mechanical arm joint is not working, in order to avoid damage of the space mechanical arm joint under the influence of the environmental temperature, the heating sheet 8 and the heat insulation material 3 are used to ensure that the space mechanical arm joint is still within the temperature index range in the 4K cold black space environment, wherein the temperature measuring sensor 1 collects the real-time temperature of the electric box shell 9, and the heating sheet 8 starts to work only when the real-time temperature of the electric box shell 9 is lower than the preset temperature. Meanwhile, the graphite film 2 is fixedly connected to the inner wall of the space mechanical arm joint shell 5 through the heat-conducting glue 6, and the annular heat pipe 4 is installed on the +X and-X sides of the joint shell 5, which ensures the effective heat conduction of the joint shell 5 around. This feature can better improve the temperature distribution uniformity of the space mechanical arm joint in orbit. When the space mechanical arm joint is working, the brake, the motor and the harmonic reducer in the space mechanical arm joint shell 5 and the electric box outside will generate a large amount of heat. At this time, the heat dissipation surface 7 arranged on the space mechanical arm joint shell 5 and the electric box shell 9 will guide the heat to the cold black space environment. When a certain direction of the space mechanical arm joint faces the sun, the heat dissipation surface 7 facing the sun cannot effectively dissipate heat, but the heat dissipation surfaces 7 in other directions can still ensure that the heat generated when the space mechanical arm joint works is guided to the cold black space environment.

[0037] It should be understood that the various forms of flow shown above can be used to reorder, add or delete steps. For example, the steps described in the present disclosure can be executed in parallel, in sequence or in different orders, as long as the desired results of the technical solutions of the present disclosure can be achieved, which is not limited herein.

[0038] The above specific embodiments do not constitute a limitation on the protection scope of the present application. Those skilled in the art should understand that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent replacement and improvement made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A temperature control device for a space manipulator joint, characterized by, The temperature control device comprises a heating sheet, a heat dissipation surface, a temperature sensor, a heat pipe, a graphite film and a thermal insulation material. The heating sheet and the heat dissipation surface are arranged on the outer wall of the electric box shell of the space mechanical arm joint and the outer wall of the joint shell of the space mechanical arm joint, and are arranged on the outer wall of the joint shell except the side wall of the joint shell where the female end of the space mechanical arm joint is located. The heat dissipation surface is sprayed with white paint, the absorption rate of the white paint to solar radiation is 0.12-0.16, the infrared radiation absorption rate is 0.90-0.95, and the heat dissipation direction of the heat dissipation surface includes and is not less than three-dimensional direction. The heat pipe is installed on the outer wall of the axial two ends of the joint shell through screws, the axial two ends of the joint shell are the male end and the end cover respectively, the heat pipe is fixed at the interfaces of the male end and the joint shell body and the end cover and the joint shell body respectively, and the heat pipe is annular. The graphite film is fixed on the inner wall of the joint shell through heat-conducting glue, and the thermal conductivity of the graphite film is 1200 W / (m·K). The thermal insulation material is wrapped on the outer wall of the joint shell and the electric box shell, and all of the heating sheet, the temperature sensor and the heat pipe are wrapped in the thermal insulation material except the heat dissipation surface.

2. The temperature control device of a space manipulator joint according to claim 1, characterized in that, The temperature control device of the space mechanical arm joint further comprises a control unit, the control unit is electrically connected with the heating sheet and the temperature sensor, the control unit receives the temperature information collected by the temperature sensor, and judges whether to send a control signal according to the temperature information, and controls the heating sheet to heat the joint shell and the electric box shell.

3. The temperature control device of a space manipulator joint according to claim 1, characterized by, The installation position of the temperature sensor is kept away from the heating sheet and the heat dissipation surface, so as to ensure the normal work of the temperature sensor is not affected by the heating sheet and the heat dissipation surface.

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