Papers by Author: Xiu Ting Wei

Abstract: Ca₃Co₄O₉ and Ca_3-xSm_xCo₄O9 powders were prepared by sol-gel process. The Ca-Co-O thermoelectric material ceramics were prepared. The ceramics materials were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The microstructure and thermoelectric properties of ceramics were researched. The results indicate that the crystal of Ca_3-xSm_xCo₄O₉ with Sm adding growth ideally, the material had high density and low pore rate. The Ca_3-xSm_xCo₄O₉ ceramics contain directional array plate-shaped grains with layered structure. The thermoelectric properties of Ca_3-xSm_xCo₄O ceramics were excellent. There were high Seebeck coefficient and high electrical conductivity for Ca_3-xSm_xCo₄O₉ ceramics. The power factor increased with temperature increasing.

Abstract: At present, most of the robots’ intelligent level is not as high as needed and they can’t accomplish some special tasks successfully under complicated circumstances. A kind of robot master-slave control system based on LabVIEW is designed, which allows operators control robots working in dangerous environment such as high radiation, ultrahigh temperature through outside input device. The device should connect with the master computer. This kind of operation mode can not only make full use of human intelligence, but also exploit the robots’ ability of being able to work in the abominable environments, making human and the robot fully complement each other's advantages. At the same time, the robot master-slave control system based on LabVIEW is easy to develop and maintain for its good portability and scalability.

Abstract: Depended on the continuous development of nanotechnology, many micro-nano positioning platforms have been developed. Considering the actual engineer need, technologies for design of the positioning platform with both large travel and nano scale accuracy have become an important research direction. Several large travel driving systems with nano resolution are compared, and further key technologies of large travel and ultra precision for design are also discussed. Analysis result is that there are two kinds of types of micro-nano positioning platform at present, that’s flexible hinges arranged structure and integrative mechanism of both general driving system and flexible structure. Merits and shortcomings for these two kinds of micro-nano positioning platforms are all presented and some useful conclusions are brought forward.

Abstract: Redundant parallel robots have been under increasing developments from a theoretical view point as well as for practical applications. Compared with the traditional parallel manipulators, they have such merits of more load, faster speed and higher accuracy. The method about how to build up redundant actuation parallel robot is introduced. Considering that the kinematic joint and limb are basic elements to constitute a proper parallel robot mechanism, special Plücker coordinates is adopted to describe the displacements of the output link of a limb or the robot mechanism. Then the principle for design of the redundant actuation parallel robot mechanisms is presented and example of the 2RRR&2PP parallel robot mechanism is brought forth and analyzed by this method.

Abstract: A type of 4-PPPR parallel manipulator is presented. The kinematics model of this mechanism is founded and kinematics solutions of both direct and inverse are given in closed form by means of coordinate transformation. For convenience to analyze the same kind of mechanisms, a new concept of even-group decoupling is put forward from a more common sense. A study is made on the 4-PPPR parallel manipulator using this method and it proves to have excellent character of decoupling which is of great importance for its path planning and real control.

Abstract: On one hand, parallel machine tool enjoys many advantages over conventional serial counterpart, on the other hand, it also suffers from the disadvantages of coupled position and orientation, difficulty in kinematic modeling, strict requirements for components and difficulty in manufacturing of the spherical joint adopted in some limbs. Hybrid mechanism, however, will serve the turn in some cases. By using a three degree-of-freedoms parallel mechanism and a slide worktable which will fulfill one movement, a novel four degree-of-freedoms hybrid machine tool is put forward. The kinematic solutions are analyzed and closed-form kinematic solutions are given. The methods and theories adopted here can be used for design of other types of hybrid machine tools.

Abstract: Singularity is a basic problem for parallel mechanism design because of its many negative influences on the mechanism performances. Traditionally, three kinds of singularities are suitable for analysis of the parallel mechanisms. By considering both the common and redundant actuation parallel mechanisms, general kinematic model is used to obtain input factor matrix and output factor matrix. Based on ranks of the two matrices, the singularity type becomes easy to judge. And the second kind of singularity can be reduced or eliminated by adding special redundant actuation sub-chains. A two-degree-of-freedom parallel mechanism is provided to illustrate the method about how to create the needed redundant actuation sub-chains.

Abstract: For some circumstances, it would be extremely dangerous to use direct human labor and then robots are often required to complete those tasks in this kind of environments. Unfortunately, computer control and intelligence are not sufficiently developed to permit the robots to fulfill these advanced technical tasks only by their own initiative. Tele-operation robot may be a good way for this problem. Robots will fulfill the given task at the real environment to avoid the possible harm to people and engineers will give out the proper instructions to robot in tele-operation mode. A type of manipulation robot will be introduced and key technologies will also be explained. It synthetically adopts wireless network video technology, photoelectric sensor technology and wireless Bluetooth technology. By this method, the operator can obtain even more information of the working environment, and the robot will also complete the dangerous task more effectively.

Abstract: Garbage cleaning robot will gather and process most of the garbage under certain circumstance for people. It can economize labor, enhance efficiency and improve the working environment. Unfortunately, most garbage-gathering devices of these mechanisms are singular and can be used for only one kind of environment as far as the land and water conditions are concerned. A kind of new amphibian garbage cleaning robot is brought forth and analyzed from three aspects, including mechanical structure, control system and programming method. And prototype of the robot is given. Analysis shows that this robot can directly move either from water to land or from land to water and above all, the robot has the advantage of low cost, long duration, better rigidity and convenient to operate.

Abstract: For most transducers, the two kinds of displacement and angular variants can not be captured at the same time. While for the unrestricted object, it often translates and rotates synchronously. For some important or special application fields, it is becoming more and more important to find a way to acquire all the six motion signals concurrently. Based on the parallel robot technology, a novel type of this kind of device is brought forth. It is composed of the end-effector, the stationary platform, and six sub-chains. It can translate along and rotate around any one of the three axes. Main structure and operation principle of this device are both described and analyzed. Measurement circuit system is designed and how to handle the twelve input signals is also explained. Finally the program flowchart and simulation examples are given.