The Multi-Field-Coupled Model and Optimization of Absorbing Material's Position and Size of Electronic Equipments

There are three fields in electronic equipment such as structure deformation (S), temperature (T), and electromagnetic (EM) fields. Both deformation and temperature will affect the electromagnetic shielding performance of the equipment considerably, particularly in the case of enclosure with small volume and high packaging density. Because the position of electronic device and the shape of outlet will be changed with structural deformation, there must be therefore an adherent relationship among three fields. To begin with, this paper presents a three-field-coupled model called STEM. Then, to enhance the capability of electromagnetic shielding of the equipment, an efficient way is to attach absorbing material to the inside of it. Under the condition of pregiven material characteristics itself, the position and size of absorbing material are of significant effort on electromagnetic shielding. The optimization model based on STEM is developed in this paper. Next, the numerical and practical experiments of an actual enclosure are given to demonstrate the feasibility and validity of the model and methodology.

Nondimensional Analysis of Fractional-Order PDD1/2 Control of Purely Inertial Systems

The paper discusses the performance of the PDD1/2 control scheme, which is an extension of the classical PD scheme with the introduction of the half-derivative term. The comparison between the PD and the PDD1/2 schemes is performed with reference to a second-order purely inertial system, using a dimensionless approach for the sake of generality. The influences of the sampling time and of the saturation are taken into account. The results show that the introduction of the half-derivative term, in proper combination with the derivative term, reduces the settling time under the same conditions of maximum control output and null overshoot.

Conception and Implementation of a Dual Data Acquisition System on an Eight-Axis High-Speed Tube Cutting CNC Machine

Precise and fast position measurement has been a challenging problem in computerized numerical controller (CNC) machines where parts need to be processed at a high speed. This paper inspects data acquisition and processing on a high-speed tube cutting Siemens 840D CNC machine with Windows NT.40 operating system and analyzes the constraints of the old procedure on the production speed. The more efficient technical tactics are proposed and implemented. The laser is added to the system to perform the same data acquisition while the function of the capacitive sensor is kept. A dual data acquisition system is thus created and the old one functions as a backup. In the retrofit, the affordable and practical data communication method is used, the sensor physical movement is avoided, the algorithm is optimized with requirement of less data, and computation of the algorithm is moved from numerical controller unit (NCU) to personal computer unit (PCU). For every tube part, the laser approach reduces the data acquisition and processing time to 4 seconds, compared to 12 seconds with a capacitive sensor.