CONTROL OF ROBOT DRIVEN BY MULTIPLE ULTRASONIC MOTORS BASED ON ROBUST PARAMETER DESIGN

An ultrasonic motor （USM） is difficlt to be mathematically described because of its complex energy conversion and nonlinear parameters from increasing temperature and changing operating conditions. To achieve good performance of a three-joint robot directly driven by USM, according to the operating characteristics of USM, a new position-velocity feedback control strategy is proposed. In the control strategy, there are a total of 18 controller gains to he tuned. Through a series of ＂Design of Experiments＂ by the robust parameter design, an optimal and robust set of proportional integral derivative （PID） controller gains is obtained. Results show that the control strategy can achieve the best performance of the robot and the robust parameter design is effective and convenient to USMs.

炼铁厂高炉电液喷射管式自动控制装置及其应用

高炉减压阀组液压系统控制,一直使用的是日本NIRECO公司生产的电液喷射管式自动控制装置,主要应用于宝钢高炉以及热轧等设备所需的空气、煤气、供水等流体输送管路控制上,属于上世纪七十年代的早期技术应用,主要规格有EHJ换位器、AJ系列换位器、R形调节机构等,其功能是把液压站输出的液压能转化为机械能,控制一个流体输送管路上的阀门(主要是蝶阀或球阀)的开闭位置和速度,从而实现对输送介质流量的控制,该系统备件核心部件是一种电液伺服阀,为射流管阀结构。现在以常用的EHJ换位器为例,探究了其工作原理、存在的问题以及如何进行改进。

Calibration of laser beam direction based on monocular vision

In the laser displacement sensors measurement system,the laser beam direction is an important parameter.Particularly,the azimuth and pitch angles are the most important parameters to a laser beam.In this paper,based on monocular vision,a laser beam direction measurement method is proposed.First,place the charge coupled device(CCD)camera above the base plane,and adjust and fix the camera position so that the optical axis is nearly perpendicular to the base plane.The monocular vision localization model is established by using circular aperture calibration board.Then the laser beam generating device is placed and maintained on the base plane at fixed position.At the same time a special target block is placed on the base plane so that the laser beam can project to the special target and form a laser spot.The CCD camera placed above the base plane can acquire the laser spot and the image of the target block clearly,so the two-dimensional(2D)image coordinate of the centroid of the laser spot can be extracted by correlation algorithm.The target is moved at an equal distance along the laser beam direction,and the spots and target images of each moving under the current position are collected by the CCD camera.By using the relevant transformation formula and combining the intrinsic parameters of the target block,the2D coordinates of the gravity center of the spot are converted to the three-dimensional(3D)coordinate in the base plane.Because of the moving of the target,the3D coordinates of the gravity center of the laser spot at different positions are obtained,and these3D coordinates are synthesized into a space straight line to represent the laser beam to be measured.In the experiment,the target parameters are measured by high-precision instruments,and the calibration parameters of the camera are calibrated by a high-precision calibration board to establish the corresponding positioning model.The measurement accuracy is mainly guaranteed by the monocular vision positioning accuracy and the gravity center extraction accuracy.The experimental results show the maximum error of the angle between laser beams reaches to0.04°and the maximum error of beam pitch angle reaches to0.02°.

A New Type of Seiberg-Witten Map and Its Application

Deformation quantization is a powerful tool to deal with systems in noncommutative space to get their energy spectra and corresponding Wigner functions, especially for the ease of both coordinates and momenta being noneommutative. In order to simplify solutions of the relevant .-genvalue equation, we introduce a new kind of Seiberg Witten-like map to change the variables of the noncommutative phase space into ones of a commutative phase space, and demonstrate its role via an example of two-dimensional oscillator with both kinetic and elastic couplings in the noneommutative phase space.

SOFT SWITCHED SYNCHRONOUS RECTIFIER WITH PHASE-SHIFTED FULL BRIDGE CONVERTER AND ITS SMALL-SIGNAL ANALYSIS

By using the output inductors and body capacitances without adding any component compared with hard switching synchronous rectifier,the topology of a soft switched synchronous rectifier with phase-shifted full bridge zero voltage switching DC/DC converter is proposed. The converter efficiency is maximized due to soft switching of the full bridge MOSFETs and the synchronous MOSFETs, and also the low conduction loss of synchronous MOSFET. The operation principles of the circuit are analyzed in detail and the small-signal model is derived, also the converter dynamic characteristics are analyzed. Frequency responses of transfer functions under different values of transformer primary leakage inductance are discussed. The experimental results were obtained from a 400 V input and 100 A/12 V output DC/DC converter operating at 100 kHz. The results show that the converter efficiency is 2% higher in rated power than traditional diode rectifier.

Model predictive control of three-level active front-end converter with low switching frequency

In medium voltage-high power(MV-HP)applications,the high switching frequency of power converter will result in unnecessary energy losses,which directly affect efficiency.To resolve this issue,a novel finite control set-model predictive control(FCS-MPC)with low switching frequency for three-level neutral point clamped-active front-end converters(NPC-AFEs)is proposed.With this approach,the prediction model of three-level NPC-AFEs is established inα-βreference frame,and the control objective of low average switching frequency is introduced into a cost function.The proposed method not only achieves the desired control performance under low switching frequency,but also performs the efficient operation for the three-level NPC-AFEs.The simulation results are provided to verify the effectiveness of proposed control scheme.

Testing Thermal Properties of Cooling Device with Heat Pipes to Improve His Heat Transfer Ability

This paper deals about testing thermal properties of the cooling device with heat pipes at inclination position, in consequence of using the natural convection to improve heat transfer properties. Head point testing of cooling device is monitoring temperature on the aluminium block of energy converter, heat pipes and ribs under temperature condition 30 ℃ in thermostatic chamber. Testing of the device was performed at tilt angles positions 0, 10 and 20° from the vertical level. The heat flux loaded to energy converter was 450 W. The next goal of the paper is to research on influence working position of the wick heat pipe on their thermal performance. In this research heat pipes were made with capillary structure sintered from copper powder granularity 100, 63 and 50 μm filled with water and ethanol. Next heat pipe thermal performance was performed by measuring heat source and working positions. Knowledge of these two research goals can bring potential improvements in purpose of cooling device for effective heat sink from high power electronic components.

The Design of a Motion Control System for a Parallel Robot with Image Positioning

A motion control system for a parallel robot with image positioning was implemented in this paper. The system is composed of a machine vision device, a delta robot and a linear stage, and the concerned hardware, software and working methods were developed completely and verified successfully. During the phase of machine vision, the image of object was captured by camera, and then the process of smoothing filter, threshold algorithm and edge detection, was applied so as to obtain the edges of image. Finally, DV-GHT （Displacement Vector Generalized Hough Transformation） algorithm was used to recognize the center of multiple and arbitrary 2-D shapes objects. After the center of objects was recognized, the objects were delivered to the workspace of a delta robot by a motorized stage. Through the coordinate transformation between the camera and the robot system, the information of center can be converted to control commands for every working motors. Following, the delta robot picks up objects to the specified position sequentially by the trajectory planning and tracking controls. The software of C＋＋/CLI is used to achieve the phase of motion controls and the program of DV-GHT is used to detect and conduct the positions for four different characteristics of the objects simultaneously so as to indicate the delta robot to classify the objects successfully.

Investigation on the Pinch Point Position in Heat Exchangers

The pinch point is important for analyzing heat transfer in thermodynamic cycles. With the aim to reveal the importance of determining the accurate pinch point, the research on the pinch point position is carried out by theoretical method. The results show that the pinch point position depends on the parameters of the heat transfer fluids and the major fluid properties. In most cases, the pinch point locates at the bubble point for the evaporator and the dew point for the condenser. However, the pinch point shills to the supercooled liquid state in the near critical conditions for the evaporator. Similarly, it shifts to the superheated vapor state with the condensing temperature approaching the critical temperature for the condenser. It even can shift to the working fluid entrance of the evaporator or the supereritical heater when the heat source fluid temperature is very high compared with the absorb- ing heat temperature. A wrong position for the pinch point may generate serious mistake. In brief, the pinch point should be founded by the itcrativc method in all conditions rather than taking for granted.

Temperature and Concentration Fields in a Generator Integrated to Single Stage Heat Transformer Using Water/Carrol Mixture

The generator is the starter device of single stage heat transformer(SSHT) and its characteristics have main effects on the overall efficiency of this kind of absorption machines.This article reports a study of the generation of steam and changes in the concentration of the working solution(Water/Carrol mixture) into a plate heat exchanger as a function of its horizontal and vertical position by gravity effect.It is considered the analysis of six experimental tests;two were evaluated in a plate heat exchanger in a horizontal position and four in a vertical position(90 degree inclination).The generation of steam and increased concentration of the working solution are more sensitive to the vertical position of exchanger than in horizontal position.The results of numerical-experimental analysis indicates that a heat exchanger in horizontal position,the steam generation and the change in the concentration of the working solution occurring in the middle of the plate(or at greater distance depending to the thermodynamic conditions) and instantly in vertical position(at the input of the plate).