Information Technology Reference
In-Depth Information
Fig. 1. Schematic diagram of PIND system
Fig. 2. Remaindermovement in sealed
cavity relay
cause too much stress on test objects which leads to potential hazards. Therefore,
more effective test conditions of PIND should be explored to improve the detection
accuracy.
The existing researches on PIND are mainly focused on the detection systems and
algorithms. McCullough discussed the detection effect of different test conditions, but
there was no theoretical analysis [6]. Du showed that vibration acceleration and
excessive shocks could lead to the fatigue fracture of the internal structure of
integrated circuits [7]. Zhang carried out a detailed analysis of the PIND mechanics,
and proposed a dynamic model of remainders movement. However the verification
was mainly based on simulations, not experiments [8-11]. In summary, little has been
done on the movement of remainders and PIND test conditions.
The nature of the research on remainder test conditions is to select appropriate
conditions which lead to the strongest collision between remainders and the shell.
Obviously, when other conditions are fixed, the faster the initial relative velocity is,
the stronger the collision is, and the generated output signal will be stronger
accordingly.The initial relative velocity between remainders and test objects can be
used as a basis for judging the merits of the test conditions.
The shell of sealed relays is often made of metal alloys, so the remainder
movement can not be directly observed.Previous studies of the test conditions were
only based on system output signal analysis or modeling derivations, the visual
inspection were impossible and the detailed remainder movement could not be studied
experimentally due to the restriction of experimental conditions. Further, the
remainder motion is a collision process with high frequency, thereforethe motion
parameters are vital in test condition researches.. Given that ordinary photographic
equipment can not obtainclear images, therefore, a movement-analysis methodof
remainders based on high-speed video technology isproposed in this paper.
2
Movement-Analysis Methods of Remainders Based on
High-Speed Video Technology
2.1
The Overall Scheme Design
The movement of remainders in relays during the tests is a complex collision and
vibration process. The research on the test conditions for relays with complex internal
structures is very difficult. The popular method is to consider the relay as a rectangular
cavity and the remainders as balls with a collision energy recovery coefficient, and the
 
Search WWH ::




Custom Search