In order to improve the precision of BGA solder joints inspection, the cross-section images of BGA solder joints are analyzed based on the 3D X-ray technology. The BGA solder joints or the BGA ball and background is segmented. The features of BGA solder joints defects and decision rules are extracted. And then inspection algorithms in vertical and horizontal cross section are presented. The defects of short circuit, shift, lacking solder, void, warpage and broken circuit can be inspected by the proposed algorithm.

Considering the joint loading-transfer effect, a 3-D finite element model which consists of thirty full-scale slabs is established. Making the aircraft loads act on different positions and calculating their vertical displacements. The results indicate that the loading area is compressive and the regions far away from loading area are tensile and that the vertical displacement curves change dramatically when aircraft wheels act on different locations.

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Kinematics and dynamics of planar 3-RRR parallel robots are presented. Firstly, kinematic equations of planar 3-RRR parallel robots are given. Then, dynamic model of the system based on Lagrange equations is obtained. Finally, the change of the drive torque and energy consumption of active joints are analyzed under the different trajectories and different loads of the moving platform is given, the results showed that the mass and trajectory of the moving platform have a critical influence on drive torque and energy consumption of the active joint. These are very important for the optimum design of the manipulator and the excellent design of the dynamic controller.

In order to reduce the position error produced by single board assembly and partial uneven surface in automated optical inspection, a new position method based on three layers of MARK point is developed. the first layer is the whole board alignment which compensate the position error of the PCB loading process, the second layer is the single board alignment which compensate the position error of the single board assembly, the last layer is the partial FOV(field of view) alignment which compensate the position error of the partial uneven surface. The experiment result proved the proposed position method improved the position accuracy obviously.