Advanced Materials Research Vols. 328-330

Abstract: Because of better comfort, air-conditioning (AC) systems are a common feature in automobile these days. Testing the performance of AC systems before automobile are sold in order to decrease AC systems repair rate become more and more urgent to auto manufacturers. An on-line test system of AC systems in automobile is designed in this paper; this system can test temperature, humidity, and wind speed of AC systems when automobile are moving on production line .Users can determine AC systems are qualified or not by these measured values.

Abstract: Identification of operator handling characteristics has got the great attention of many people, especially for the intelligence of the machine. This article designs a manual tracking control experiment to analyze the human operator control characteristics. The whole experiment system is composed by a computer and a joystick. The computer simulate the target ball’s movement, human operator can control the reference ball by the joystick to track the target ball. By changing the target ball’s speed to identify the human operator control effect .According to record and analyze the deviation of the experiment data, achieved some tracking control characteristics of the operator: first, every operator has a time delay between he discovers the target and operates the machine to track it, this time is about 0.4s, second, the operator’s tracking performance is related to his operating skill, in addition, tracking effect depends on the target’s speed, the more difficult of the experiment task is, the poorer of the tracking effect is.

Abstract: Many factors influence WEDM (Wire-cut Electrical Discharge Machining) processing precision, and the influence of various factors on the processing precision are expressed by wire electrode dynamic form ultimately. In this paper, the transverse vibration theoretical model of the axially moving electrode wire coupled with thermal stresses is established by the principle of Hamilton. The influence of various processing parameters on wire vibration are analyzed and simulated. This study provides a relevant theoretical basis for optimizing processing parameters, reducing the wire vibration and improving machining precision.

Abstract: In this paper, a modeling method is presented for networked control systems (NCSs) of electric multiple units (EMUs) with packet dropout and network-induced delay. It is assumed that the induced delay is less than the sampling period T, and the event rates (scilicet, the data packets transfer successfully rates) are fixed. The NCSs in EMUs can be described as an asynchronous dynamical systems which are driven by "events" that occur asynchronously. Using the dynamic output feedback control method, the systems exponential stability is discussed when the system state is not acquirable.

Abstract: A type of automatic positioning control system of train has been introduced. The key element of system is based on induction radio communication technology. System is composed of four parts: ground control unit, communication unit, train control unit and external control part. The carrier of position produced by generator is amplified and sent to the coded flat cable. Then the signal is induced by antenna of train. Through control unit of train, the location of train will be gained. The location signal is sent out to PLC control part which will control some external equipment. It is especially for real-time address detecting online of subway or light rail trains during running. Several functions of automatic stop, positioning, opening, closing and others have been achieved in this control system.

Abstract: To overcome the defects of traditional temperature detecting devices, this paper introduces a temperature detecting system based on 1-wire digital thermometer DS18B20. It consists of programmable resolution 1-wire digital thermometer DS18B20, single chip microcomputer (SCM) AT89C51, and the peripheral circuits. The temperature data can be displayed on a liquid crystal display and simultaneously transmitted to a personal computer (PC) via serial interface for remote monitoring after it is detected by sensors. The operating process of DS18B20 and the connection between AT89C51 and PC are introduced in detail. We also provide the main program flowchart and the flowchart of accessing DS18B20 in this paper. The simulation of the whole process is successfully implemented with software PROTEUS. This system can be widely applied in environment monitoring and process control.

Abstract: This paper presents a predictive control method of heating system of heating power station. Firstly, the forecast of heating load is introduced using time series analysis, and the obtained result is used as an energy-saving initial value of predictive control system. Secondly, model simplification method is given and immediate control law is derived, the predictive model order is decreased from N to n. Simplification model satisfies the demand of real-time property of the control system. Thirdly, predictive error correction is used to replace error correction to implement the correction of optimum control of the system, which can improve adaptability and robustness of the system. Finally, simulation of heating system of heating power station is conducted and the results prove that the algorithm is effective in ensuring real-time control, improving tracking and robustness property.

Abstract: Because of steel cord conveyor belt with high load operating and complex conditions of coal mine, it is prone to cause conveyor belt horizontal rupture. It will bring tremendous hazards for coal mine production. Twelve time domain features of joints signals, broken wires signals and abrasion signals for steel cord conveyor belt were extracted with weak magnetic detection system. The algorithm of combining rough set based on information entropy with multi-classbased on binary tree was proposed to classify the three categories signals. The experiment results show that rough set reduction algorithm based on information entropy can effectively achieve feature reduction and classification speed of multi-classclassification algorithm based on binary tree can be improved by rough set feature reduction without changing classification accuracy.

Abstract: This paper describes a low-power 1.2 V 8-bit 1Gs/s two-channel pipeline ADC. The novelty of the designed ADC lies in: ameliorating the two-channel pipeline structure that consists of 1.5-bit multiplying DAC (MDAC). In order to reduce the power consumption and improve the sampling speed, the dual-channel pipeline Time Division Multiplexing operation amplifier and double or single channel flash ADC are used; in the front-end Sample-and-Hold circuits, switch-linearization control circuits(SLC) driven by a single clock signal is applied to solve the problem of time-skew and time mismatch between two channels. The pipeline ADC is designed with 90 nm CMOS process. From the simulation results of the designed ADC, we can draw that the SFDR is 42.3 dB; the SNR is 32.7 dB under the usual temperature. The ADC achieves 21 mW power-dissipation, 8 resolution and 1.01 GS/s sampling speed. So the design meets high speed, high precision and low power dissipation at the same time.

Abstract: A high-precision amplifier design in a stander 0.35μm CMOS process was proposed. This design obtains a high-performance by proper application of dynamic element matching to a second generation current conveyor (CCII). In comparison with the traditional CMOS circuits, the proposed approach can not only increase the output swing and decrease output resistance but also compensate the effect of the input offset and 1/f noise voltage. The simulation results show that the gain error is reduced 38~50 times than the traditional amplifier, and the precision is significantly improved. So the proposed circuit is suitable for the design of special amplifiers used in various detections and signal mediation.