Advanced Materials Research Vol. 981

Abstract: In this paper, the problem of the exponentially stable sampled-data control was investigated for a class of uncertain systems. Based on the input delay approach, the system was modeled as a continuous-time system with the delayed control input. Attention was focused on the design of a state feedback sampled-data controller which guarantees the exponential stability of the closed-loop system for all admissible parametric uncertainties. Using linear matrix inequality (LMI) approach, sufficient conditions are obtained. Simulation example was given to demonstrate the effectiveness and correctness of the proposed method.

Abstract: due to the characteristics of large delay, nonlinear super-heater, time-varying, multivariate and self-balance ability .It is difficult to establish accurate mathematical model, this paper uses the cascade fuzzy control, realize the effective control of the main steam temperature. Simulation results show that, the temperature cascade fuzzy control has fast dynamic response, good steady-state performance and robustness.

Abstract: Impact velocity is an important performance parameter for capacitive RF-MEMS switch. This paper establishes a differential equation, in order to analyse the influencing factors of impact velocity. The simulation results show that impact velocity can reach 1.5m/s when bias voltage equals to 0.7V, frequency equals to 3×10⁵Hz, voltage type adopts rectangular wave.

Abstract: This paper presents the calculation model of capacitive RF-MEMS switch for the isolation and insertion loss, and then adopts CST software to simulate microwave performances. The simulation results show that return loss can reach-21.5dB and isolation can reach-0.26dB when the distance between contacting metal and dielectric layer adopts 2ڌ̏̽, 6×10³ڌ̏̽² of contacting area and 20ڌ̏̽ of groove depth.

Abstract: This paper presents a LED display system triggered by the natural wind which can be used for ice lantern, the system includes a signal detection unit, control unit and LED display unit. When the system detects a natural wind signal , the center control module will make a signal processing for the signal, LED display module set the display mode according to the results of processing options, the display modes include the following, the LED lamps sequentially turned on in accordance with wind direction, or make the pattern presetting on the LED array move with the natural wind direction , when the natural wind signal is very weak, system will control LED array display static pattern. A stable system model is realized in accordance with the design requirements, after testing, system performance is stable, reached the set requirements.

Abstract: Quality of human pulse waveform graph determine the results of the disease analysis and affect disease diagnosis accuracy，Through the MATLAB software design of a digital filter is used to filter the pulse signals, Optimizing the pulse waveform graph. And the simulation test of digital filter, results showed that filter completed the pulse wave denoising.

Abstract: The induced magnetic field is an important parameter in submarine degaussing, the measurement of which by course-changing method now wastes much time and force. By analysing the producing and measuring theory of the induced field, a method for measuring the submarine’s induced magnetic field by geomagnetic simulation was founded. The geomagnetic field can be changed by galvanizing the geomagnetic simulation loops, and the submarine’s induced field can be calculated according to the change of the submarine’s field before and after galvanizing, which can achieve the goal of fast measuring the submarine’s induced field. The experiment of the mockup showed that the method is feasible, and the submarine’s induced field can be measured fast and accurately. In the actual measuring of submarine’s induced magnetic field and degaussing work, the method has important application value.

Abstract: The paper described a sort of power supply system featured as a hybrid of Rogowski coil, super capacitor and Li-battery. The proposed power supply obtains energy from the magnetic field induced by installing a Rocowski coil on the cable. The design of the power supply system is introduced in the paper. The results of test show that the power supply system can provide a stable ±12V, +5V voltage to the on-line monitoring devices.

Abstract: Rogowski coils is a kind of special structure hollow coils, it has good linearity, no iron core, no magnetic saturation phenomenon and wide measuring range, which has been used to measure all kinds of various changes current. The current transformer consist of PCB Rogowski coil and digital integrator has been designed, includes the structure of PCB Rogowski coils and the principle digital integrator based on AD7742. The test of PCB current transformer show that it has high accuracy and PCB coils has good linearity. It can meet the requirement of current measurement.

Abstract: In the field of industrial measurement, capacitive sensors are widely used. In many types of capacitive sensors, the output capacitance value range of many sensors is very small, generally between 10pF to 1000pF, but accuracy is usually required to be more than one thousandth. The conventional method of detecting capacitance value is generally the capacitor charge and discharge. By charging and discharging time statistics and calculations, capacitance values are deduced finally. The inherent disadvantages of this method are: (1) Temperature drift of the measurement circuit is large. (2) The spatial magnetic field under special circumstances impact on measurement circuit. (3) Long-term stability of the device will deteriorate. In this paper, a "capacitance measurement method with reference and comparison" is summed up through a lot of measurement experiments of humidity capacitance, that method can eliminate three kinds of defects in the capacitor charging and discharging process.