Advanced Materials Research Vol. 703

Abstract: For improving the vehicle handling at high speed, an optimal controller was introduced for the four-wheel-active-steering vehicle. A closed-loop system was set up by combining vehicle model with driver model. The simulation test in the closed-loop system was carried out to verify control effect of such a optimum controller. Simulation results show that the four-wheel-active-steering vehicle under the optimal control can gain expected control effect such as wiping out sideslip angle and tracking desired yaw rate and so on. In addition, the four-wheel-active-steering vehicle with the optimal control can also track desired trajectory and its following accuracy is better than the traditional front-wheel steering vehicle. So, the steering response characteristic for the four-wheel-active-steering vehicle at high speed is improved.

Abstract: According to the principle of constant-precision frequency measurement in the field of electrical automation, the relationship of frequency measurement precision and gate time is analyzed. And the constant-precision frequency meter based on MCU and CPLD is designed in this paper. It can keep the relative error being 0.0001% constantly when frequency measuring within the range of 0.1Hz to 1MHz. Its simulation results by MUX+PLUS is presented.

Abstract: The design of programmable control voltage/current source based on MCU C8051F410 is introduced. The system mainly consists of D/A converter with PWM, voltage/current conversion circuit and digital display circuit. It can provide with DC voltage within the ranges of 0 to 200mV, 0 to 2V, -10V to +10V; and provide with DC current within the range of 4 to 20 mA. The programmable control voltage/current source can be used as the standard signal source for thermodynamic instrumentation, especially for the adjusting and testing for ADC or precise litter signal amplifier in the field of electrical automation.

Abstract: The PWM signal generator, in which the DC voltage, sine AC or arbitrary waveform signal can be the base wave to control the duty cycle, is designed in this paper. The high-speed comparator modulates the two signals, one is the base wave signal generated by MSP430F169 and the other one is the PWM modulated wave signal generated by the voltage controlled oscillator, and then generates the PWM signal. The frequency of the PWM signal can be regulated, the frequency and waveform of the base wave can be programmed and the three-phase SPWM signal can be generated. The PWM signal generator can be applied in the field of converting technology in power electronics and electrical automation.

Abstract: An efficient automated milk detector based on freezing point depression is designed. This detector shares characters of high efficiency and good stability with accuracy and automation. Its main parts include temperature sensor of IC (Integrated Circuit), pinion-rack mechanism and crank-rocker mechanism and electronic control system. Monitoring in-situ change of milk freezing curve and developing efficiency of sampling can be available by means of pinion-rack mechanism and IC temperature sensor mechatronics design. As a result, adulterating status of milk can be discriminated in a rapid and accurate and automated way. The detector may be employed to detect liquid foods other than milk as well.

Abstract: The semiconductor material, SiC single crystal substrate, has been become an indispensable substrate material in the field of semiconductor lighting. In order to detect the influence of polishing interface temperature on polishing quality in chemical mechanical polishing (CMP) SiC single crystal substrate online, in this paper, according to the principle of chemical mechanical polishing, a device has been designed for detecting the polishing interface temperature in chemical mechanical polishing. AT89S52 microcontroller-based, using six 1-wire digital temperature thermometer DS18B20 to detect the temperature signal of different six locations, then to transmit out by the wireless transmission module nRF24L01 chip, and to achieve a multi-point temperature signal collection and wireless transmission. The device is simple, reliable and low cost. It will be providing a reference for temperature measurements in ultra-precision machining process online.

Abstract: The atmosphere environment pollution is still serious. The soot particle material is an important pollutant of the atmosphere. The Scattering-Integration method has some advantage, but the measurement light path adjusts difficulty. The rod particle material concentration measurement system is brought out in the paper. The particle material concentration measurement system is designed. The measurement system includes four parts: the mechanical system, the optical measurement system, the data transmission system and the automatic processing system. The system light path need not adjust while installing on the pipes. The experiment results show the system can measure the particle material concentration and the accuracy of the measurement system is improved.

Abstract: This study mainly investigates and researches the production of micro-torque limiters by using magnetic force and infrared optointerrupters therein including a permanent magnet, a magnet set, a grating disk, an infrared optointerrupter and a microprocessor, a torque-driven screw rod with the torque generated by the magnetic adsorption force. As the torque limiter is a clutch body, when the external resistance is greater than or equal to the magnetic torque, the rotation of screw rod will stop but start sliding simultaneously. When the screw rod stops rotating, the shutter detection disk also stops rotating. Correspondingly, the pulse signal output of infrared optointerrupters stops. Therefore, the motor of MCU stops by precisely determining whether the screw rod is stopped by external force with the function of torque limiters well exerted. As such, a product advantaged with streamlined sizes, long life expectancy, higher stability, low cost and handy control is reachable.

Abstract: Mechanics properties of human body mechanical movement have a lot of initiative and variability, especially sports technical movement is the day after tomorrow, spontaneous or consciously form. To a video clip, mechanics properties of human motion reflect the changes which are the important characteristics of the gradual progress in video. If we want to describe the overall content of the video, the motion properties are an essential respect. An improved radon transformation method of feature extraction for human behavior identification is designed in order to solve the sensitivity of the scaling and translation invariant of conventional radon transformation. It deduces the process of the improving method to keep the scaling and translation invariant. The experimental results show that the improving method is low computation and higher recognition rate. Also, it enhances the robustness of feature extraction.

Abstract: The aim of human mechanics is to reveal the mechanics properties of human motion. Especially, the purpose of human motion detection is detecting the moving people from continuous image sequences, extracting human body segments and then getting motion feature. The paper presents a shadow detection algorithm based on covariance difference operator based RGB color space and discusses its mechanics properties. The presented algorithm includes four steps: object detection, suspected shadow detection, shadow detection and post processing. The presented algorithm of adaptive shadow detection threshold is adopted to suppress the effect of shadow in moving object detection more effectively. The experiment results show the algorithm presented in this paper can detect shadow effectively.