Experimental Study of Dynamic Bipedal Walking Based on the Principle of Parametric Excitation with Counterweights

This paper reports some interesting results from our experimental study of parametrically excited dynamic bipedal walking. We describe the details of the walking machine that has telescopic legs, semicircular feet, free hip joint and counterweights. The walker can sustain stable dynamic walking on level ground based on mechanical energy restoration in accordance with the principle of parametric excitation utilizing the effects of semicircular feet and counterweights. Results of numerical analysis on the effect of the counterweights on the gait efficiency are also described.     

The Absorption Cross Section for Light of the Silver Grains in Photographic Deposits

Estimations of projection area of silver grains in photographic deposits were made on photomicrographs as well as counts of grains per unit area. Density of the deposit was calculated from these data employing known formulae. These were found smaller by a factor of 2-3 when compared with densities measured in diffuse light. The absorption cross section of grains for light considerably greater than their projective area is concluded. The results are in agreement with those obtained by other authors, which were, however, interpreted in a different way.     

WEB-BASED VIRTUAL CNC MACHINE MODELING AND OPERATION

A CNC simulation system based on internet for operation training of manufacturing facility and manufacturing process simulation is proposed. Firstly, the system framework and a rapid modeling method of CNC machine tool are studied under the virtual environment based on PolyTrans and CAD software. Then, a new method is proposed to enhance and expand the interactive ability of virtual reality modeling language(VRML) by attaining communication among VRML, JavaApplet, JavaScript and Html so as to realize the virtual operation for CNC machine tool. Moreover, the algorithm of material removed simulation based on VRML Z-map is presented. The advantages of this algorithm include less memory requirement and much higher computation. Lastly, the CNC milling machine is taken as an illustrative example for the prototype development in order to validate the feasibility of the proposed approach.     

Motor Restoration Based on the Brain–Machine Interface Using Brain Surface Electrodes: Real-Time Robot Control and a Fully Implantable Wireless System

The brain–machine interface (BMI) is a new approach to the man–machine interface, which enables us to control machines and to communicate with others without input devices, but directly using brain signals. We describe our integrative approach to develop a BMI system using brain surface electrodes for motor and communication control in severely disabled people. This includes effective brain signal recording, accurate neural decoding, robust robot control, a wireless fully implantable device, a non-invasive evaluation of surgical indications, etc. In addition, the inspection and addressing of neuroethical issues is indispensible when undertaking work in this field.     

Mathematical modelling and computer simulation of nitriding

Abstract

Mathematical modelling of matter transmission during gas nitriding has been deduced by a numerical calculation in the present study. The diffusion coefficient of nitrogen in 38CrMoAl steel and the matter transmission coefficent in the interfacial reaction have been measured. Owing to the large difference between the nitrogen activity at the surface of the workpiece and that of the gas phase during the nitriding process, it is very difficult to control the nitrogen potential and balance the nitrogen activity. In order to solve this problem, is it proposed that the nitrogen potential is dynamically controlled by computer. Under conditions of high nitriding speed, the computer controlled technique used in practical manufacture shows good reproducibility and can control the nitrogen potential accurately, thereby reducing the brittleness of the nitrided layer.     

Investigation of factors affecting pellet strength in straight grate induration machine

Abstract

During induration in a straight grate machine, the green pellets pass through four different thermal treatments, namely drying, preheating, heating and cooling. The pellet bed is fired with downdraught firing leading to thermal gradients through the bed. Corex sludge, which is used as fuel in the pellet mix, supplies the necessary energy for uniform heating of the pellet. The physicochemical conditions, e.g. the temperature and oxygen partial pressure mainly depend on the amount of fuel incorporated in the pellet mix. As a result the percentage and the distribution of various phases in the pellets vary, leading to deviation in quality. To study the distribution of phases and their impact on cold crushing strength at different carbon levels (1·20 and 1·35%), pellets from different layers of the induration bed in an industrial straight grate were characterised. It was observed that the strength of the pellets varied from 142 to 268 kg/pellet and 128 to 245 kg/pellet across bed, with carbon 1·20 and 1·35% respectively. It was found that middle layer pellets had higher strength compared to top and bottom layers. It was observed that amount of hematite, magnetite, porosity and the pore size plays a significant role on the pellet strength. Pellets with 1·20% carbon showed better physical and microstructural properties across the pellet bed compared to pellets with 1·35% carbon.     

22—STUDIES ON THE NOBLE COMB. PART I: THE INFLUENCE OF CIRCLE TEMPERATURES

The combing performance of the Noble comb is dependent on the withdrawal force of the ingoing slivers, the setting of the drawing-off rollers, the absolute temperatures of the small and large circles, and the quantity of ether-extractable matter present. The withdrawal force has the greatest effect on the production of minimum noil and is also a major factor in the selection of the optimum temperatures to be used at any given setting. A theory of fibre selection and fibre migration is presented in order to explain the experimental conditions characterizing minimum noil. It is shown that changes in mean fibre length sometimes conflicted with changes in percentage noil. Certain modifications to the comb were made in order that the combed slivers from the small and large circles could be separated.     

机器视觉在基片自动分类机中的应用

介绍了机器视觉的基本原理、组成结构及其在自行研制的基片自动分类机中的应用，展示了面阵CCD在基片自动分类机视觉系统中的重要作用。     

Model Learning with Local Gaussian Process Regression

Precise models of robot inverse dynamics allow the design of significantly more accurate, energy-efficient and compliant robot control. However, in some cases the accuracy of rigid-body models does not suffice for sound control performance due to unmodeled nonlinearities arising from hydraulic cable dynamics, complex friction or actuator dynamics. In such cases, estimating the inverse dynamics model from measured data poses an interesting alternative. Nonparametric regression methods, such as Gaussian process regression (GPR) or locally weighted projection regression (LWPR), are not as restrictive as parametric models and, thus, offer a more flexible framework for approximating unknown nonlinearities. In this paper, we propose a local approximation to the standard GPR, called local GPR (LGP), for real-time model online learning by combining the strengths of both regression methods, i.e., the high accuracy of GPR and the fast speed of LWPR. The approach is shown to have competitive learning performance for high-dimensional data while being sufficiently fast for real-time learning. The effectiveness of LGP is exhibited by a comparison with the state-of-the-art regression techniques, such as GPR, LWPR and ν-support vector regression. The applicability of the proposed LGP method is demonstrated by real-time online learning of the inverse dynamics model for robot model-based control on a Barrett WAM robot arm.