Industrial robots have been wildly used in machining applications due to its high flexibility, high automationlevel and lowcost. However, the relatively low stiffness of robots seriously influences their machining accuracy and quality. This paper built a singularity measurement model of the robot posture under the constraint of joint-limits. Based on the robotic static stiffness model, a comprehensive robotic stiffness performance evaluation method was proposed. Finally, on the basis of redundant degree of freedom, an off-line machining configuration optimization method of six-revolute serial robots was addressed, which far away from singularity and joint-limits meanwhile achieved the optimum stiffness. Themethod could improve robotic kinematics performance and machining quality effectively through machining experiment.

Riveting is the main connection mode in aircraft assembly. High efficiency and high quality drilling and riveting technology is the key to improve the assembly quality and assembly efficiency of aircraft. With its high flexibility and low cost, the robot drilling and riveting system has gradually entered the field of aircraft assembly and becomes a new force in the automatic drilling and riveting system. Firstly, the research status and application of robot drilling and riveting system at home and abroad are introduced and analyzed. Then, the main problems existing in the robot drilling and riveting system at home are summarized. Finally, the key technologies to be solved in this area are summarized, which provide reference for the researchers.

Traditional industrial robots have advantages of large workspace, compact structure, and good flexibility, and have been gradually used in the high precision metal cutting fields of drilling, milling and grinding instead of material handling, spot welding, spray painting and other operations. However, the stiffness of industrial robots is weak compared with metal cutting machine tools. The weak stiffness of the robot makes the tool deviate from the desired machining trajectory, and makes the robot easy to chatter when it is subjected to the external excitation force, which affects the machining accuracy of the robot; in addition, the internal backlash of the joint reducers is also one of the most important factors affecting the machining accuracy of the robot. The research status of robot stiffness optimization, robot machining error compensation, backlash compensation of the robot and vibration suppression of the robot are summarized. Two kinds of robot structure improvement design are proposed to increase the accuracy of the robot, the robot structure of non-backlash driving based on dual-motor drive and the high stiffness robotic arm based on parallelogram mechanisms are respectively described. And the structural characteristics of the robot are elaborated.

The machining and assembly errors will result in misalignment between the real and nominal 3D models of aircraft panel. To solve the low position accuracy of holes caused by the misalignment, a positional error compensation method based on binocular vision measurement system is proposed. Firstly, the workflow of the robotic drilling system is introduced to choose a vision measurement system that can meet the drilling requirement. Then the component and the workflow of the vision measurement system are proposed. Finally, the coordinate extraction of datum holes, the error compensation of holes and database operation in the vision measurement system are introduced in detail. The positional error compensation method based on binocular vision measurement system can obtain the coordinate of datum holes, compensate the positional errors of holes, and write the compensation information in the database to enhance the position accuracy of holes.

The automatic spraying of huge aviation components is an integration of machinery, electronics, controlling, sensing and software and hardwares. It is the key manufacturing process for automatically coating the large aviation components, and is one of the key technologies to compete in the international market for large aircrafts. This paper mainly introduces the state of current research on coating robots, the latest development of coating robot, and the major problems in development. It also discusses the development tendency of the technology in the future.

The vision aided positioning method of automatic riveting for industrial robot is studied. The cross link structured light curves which are reflected on the camera plan can be obtained by polynomial fitting method, are used to calculate the three dimensional information of aircraft surface. Position and posture of riveting hole can be calculated by the interpolation method according to the three dimensional information of aircraft surface and the corresponding relationship between the riveted hole and the curves of the cross link structured light. The position and the attitude of the riveted hole can be revised well for the end of an industry robot that is working with the planning route mode. The accuracy and the real time performance can be realized when industry robot automatic riveting under a common application range with common rivets.

Industrial robots have been increasingly applied to aircraft automation assembly lines due to their high flexibility and low cost, but poor absolute positioning accuracy of industrial robot is the bottleneck that constrains their development. In order to further improve the positioning accuracy of the robot, a positioning accuracy method based on mechanical joint feedback is proposed. This method is applied to control the robot by installing the absolute gratings at the joints and the semi-closed-loop control is established for reducing the effect of the joint error on the position of the end effector and increasing the positioning accuracy of joints. The experimental result shows that the absolute error of the robot is reduced from 1.125mm to 0.167mm. This method can effectively improve the absolute positioning accuracy of the robot and realizes the high precision control of the robot.

HIL (Hardware-In-the-Loop) simulation is one of the key technologies for aerospace devices to imple-ment microgravity simulation experiment on the ground, where the hardware system needs high carrying capacity, high frequency response and high precision control performance. Therefore, a hybrid pneumatic-electric actuator is proposed for the 6-DOF microgravity simulation platform. Each leg of the platform is composed of a cylinder and a servo motor in parallel. The cylinders support 80%-90% of load and the servo motors ensure the high accuracy of the control system. Since the pneumatic force control system is a highly nonlinear system, an integral-linear active disturbance rejection controller (I-LADRC) is proposed. Compared to the PID algorithm, this controller provides a higher precision, faster response and stronger robustness.

This paper aimed to solve the problems in the manufacturing process for typical T-stiffened composite structure, including difficulty to be filled of the T-stiffened area, complex and unrepeated of the process. A novel approach of vacuum-assisted liquid molding co-curing process was developed to manufacture the T-Stiffened composite structure with foam cores filled in the stiffened area. Two custom tools were designed in the new approach. During plying procedure, a well-tailored foam core and a ply-guiding plate were used to realize the precise dimension and quality control of the Tstiffened area. In the injection process, a steel pressure plate was introduced, which helped to get double-sided smooth Treinforced panel using a single-side mold. The manufactured T-stiffened panel was demonstrated to be good in quality. The results are of great reference value for the applications and developments of low cost integral manufacturing technic for stiffened structures on airplanes.

Hollow structure specimens which represent the similar topology of components are produced, and dry blast and wet blast are used to strengthen the surface. Then, fatigue tests are carried out. The experimental results show that the fatigue property of polished specimen is the lowest, and specimen by the dry blast process is higher and the fatigue life is as 10.4 times as that of polished specimen. The experimental results also show that the fatigue property of specimen by wet blast processed is the highest, and the fatigue life is at least as 3.3 times as that of specimen by dry blast processed. This conclusion can be useful to improve shot peening parameters.

MBD technology ensures the data uniqueness of aircraft design and manufacturing, and greatly shortens the development cycle of the product. However, there are still many problems in the process of aircraft manufacturing process review such as heavy workload, long time consuming and easy to miss, etc. In this paper, we developed a set of process review software including comprehensive custom extraction and non-geometry/geometry information contrast based on CATIA re-developing. Through engineering verification, it is found that the software can greatly increase the efficiency and quality of aircraft design approval and production process preparation.

Titanium alloy has been widely used for aerospace fasteners industry due to its low density, high yield strength, and good corrosion resistance. The research and prospect of titanium fasteners are reviewed. Nationally and internationally, the recent development and application of titanium fasteners are introduced. The tensile properties of some candidate alloys for high-strength fastener application are summarized and compared. Some high-strength β-titanium and the technical processes of bar or wire for fasteners are introduced on the basis of requirement for advanced aircraft.

In order to obtain a miniaturization and light weight solid-state laser, the diode pump cooling system need to reduce its weight, a solution based on Al & Cu combinated heat sink with thermoelectric coolers is proposed. The software Flotherm is used to optimize the design of heat sink, and then verify the cooling system in the actual use of the environment. The experimental results show that the designed scheme meets the requirements of solid-state laser cooling demand, the weight loss design of the pump module cooling system has been carried out.