The Surface Coating Robot for Space Solar Cell Array Assembly
Z. Fu
a
, W.X. Yan
b
and Y. Z. Zhao
c
State Key Lab. of Mechanical System and Vibration, SJTU, Shanghai, China
a
zhfu@sjtu.edu.cn,
b
xiaogu4524@sjtu.edu.cn,
c
yzh-zhao@sjtu.edu.cn
Keywords: Robot, Space solar cell arrays, Adhesive, Surface coating
Abstract. At present, adhesive coating is by far the most widely used technique in the space panel
manufacturing. The automatic process level is essential for improving the quality and efficiency of the
space solar cell array assembly. In this study, the surface coating model for adhesive dispensing on the
space solar cells is obtained, which describes the relationship between the thickness of the adhesive
layer on the solar cell, the moving speed of the syringe and the differential pressure. Then the structure
of the surface coating robot is presented for the space solar cell arrays assembly. The experimental
results have showed that the surface coating robot can greatly improve the efficiency and quality of
the space solar cells array assembly. The adhesive no longer outflows and stains the solar cells and the
panel. This robot is useful to protect the environment and keep workers away from the poisonous
chemicals. Instead of the manual work in space solar cell arrays assembly, the application of the
surface coating robot will enhance the development of space industry.
Introduction
Recently, almost all launched aircrafts around the world employ space solar cell arrays (SSCA) as
power source [1-3]. Because the spacecrafts work in the outer space, the surroundings are very harsh.
In outer space (150 kilometers far away), the irradiation intensity is about 1360 W/m
2
, 13~17 times
greater than that on the surface of the globe, temperature varies greatly from -180 to +130℃, and the
atmosphere is full of high-energy particles. To assure a high reliability of the SSCA in this harsh
environment, the process of the solar cells array assembly, especially the surface coating operation
using adhesive to join the solar cells and the space panel together, is an essential step in production
[4]. The adhesive joining with high quality can not only withstand repeated temperature cycle but also
withstand the mechanical stress during the rocket launching.
Due to advantages of its physical properties, one bonding technique for space solar cells is the
adhesive bonding under non-vacuum condition [5-6]. The process of adhesive bonding can be
described as follows: first the adhesive is dispensed to the back of the solar cell. Then the solar cell is
placed on the solar panel. After that, the adhesive is heated and hardened. Finally, it is tested. To
finish the surface coating process automatically, we developed a surface coating robot, which realizes
the auto-coating and auto-bonding operations.
Surface Coating Robot Design
At present the manufacturing process from solar module to solar cell arrays is manual work
absolutely. The manual operation has not suited the development of new generation of solar cell
arrays. Therefore, a new surface coating robot system, as shown in Fig.1, is designed to realize the
automatic operation.
The surface coating robot consists of the mechanism of adhesive dispensing and auto-laydown, a
pneumatic system and a control system. The mechanisms of adhesive dispensing and auto-laydown
are installed respectively on the Z-axis and X-axis of the XYZ three-DOF moving device. Since solar
arrays are usually very large and at present the largest solar array is 4000 mm length and 2000 mm
width, the XYZ three DOF auto-moving mechanism is employed as support part to make sure the
high position precision. The main manufacturing process of solar arrays consists of two parts,
dispensing adhesive module and auto-laydown solar module on solar panel. Controlled by the robot,
the adhesive dispensing mechanism is in charge of distributing adhesive on solar cells. It can be seen
Key Engineering Materials 373-374 (2008) pp 774-777
online at http://www.scientific.net
© (2008) Trans Tech Publications, Switzerland
Online available since 2008/Mar/07
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publisher: Trans Tech Publications Ltd, Switzerland, www.ttp.net. (ID: 202.120.53.176-10/03/08,01:55:50)