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The Robot for Thin-film GaAs Space Solar Cells panel
manufacture
Z. Fu
a
, P.B. LI
b
and Y. Z. Zhao
c
State Key Lab. of Mechanical System and Vibration, SJTU, Shanghai, China
E-mail:
a
zhfu@sjtu.edu.cn,
b
LIPb233@sjtu.edu.cn,
c
yzh-zhao@sjtu.edu.cn
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 thin-film GaAs
space solar cell array assembly. In this study, the surface coating model for adhesive dispensing on the
thin-film GaAs 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 thin-film GaAs space solar cell panel
assembly. The experimental results have showed that the surface coating robot can greatly improve the
efficiency and quality of the thin-film GaAs space solar cells panel manufacture. 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 thin-film GaAs space solar
cell panel manufacture, the application of the surface coating robot will enhance the development of
space industry.
Keywords: Robot; Space solar cell panel; Adhesive; Surface coating
1. 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 thin-film GaAs 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 thin-film GaAs 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.
2. 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[7].
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