Because the center of gravity (CG) position plays an important role in the process of leaping over a ditch, the CG position kinematics model is built. By using this model, the CG change situation is obtained, and the ...
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An integrated micro xy-stage is designed and fabricated for application in nanometer-scale operation and nanometric positioning precision. This device integrates the functions of both actuating and sensing in the same...
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Co87Nb10Zr3,Co76Nb19Zr5,Co64Nb26Zr10 and Co64Nb16Zr20 amorphous films were deposited on noncrystalline glass substrates by DC unbalanced magnetron sputtering. The compositions of amorphous films were tailored in the l...
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Co87Nb10Zr3,Co76Nb19Zr5,Co64Nb26Zr10 and Co64Nb16Zr20 amorphous films were deposited on noncrystalline glass substrates by DC unbalanced magnetron sputtering. The compositions of amorphous films were tailored in the light of the individual deposition rate of Co,Nb and Zr. The amorphous films with the anticipated composition were prepared by means of co-sputtering Co,Nb and Zr targets simultaneously. It is indicated that there is interaction among three targets during co-sputtering. The morphology and composition of the films were observed by SEM,AFM and EDS. The structure and magnetic property were measured by XRD and physical property measurement system(PPMS) . The coercivity changes with the composition,varying from 240 to 1 600 A/m. After vacuum isothermal annealing at temperatures of 475,500,525 and 550 ℃ for 15 and 30 min,respectively,it is found that high Nb content is beneficial to improving thermal stability of amorphous films. The crystallized films have the mean grain size of 2-19 nm.
Because the movement of mobile manipulator has an effect on the obstacle-climbing performance and stability, the center of gravity (CG) position kinematics model was built. Using this model, the change of the CG and t...
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Because the movement of mobile manipulator has an effect on the obstacle-climbing performance and stability, the center of gravity (CG) position kinematics model was built. Using this model, the change of the CG and the effect of mobile manipulato's postures on obstacle-climbing performance are obtained in the process. And the dynamic model of key posture of climbing up obstacle was built. The effects of the velocity and the acceleration of the mobile manipulator on obstacle-climbing performance were calculated by this model. Finally, several experiments verified the analysis. The analysis can help to design and control the robot.
To improve the working and living environment of submarine crews, an integrated system of CO2 removal and O2 regeneration was designed to work under experimental conditions for 50 people in a submarine cabin during pr...
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To improve the working and living environment of submarine crews, an integrated system of CO2 removal and O2 regeneration was designed to work under experimental conditions for 50 people in a submarine cabin during prolonged voyages. The integrated system comprises a solid amine water desorption （SAWD） unit for CO2 collection and concentration, a Sabatier reactor for CO2 reduction and a solid polymer electrolyte （SPE） unit for O2 regeneration by electrolysis. The performances of the SAWD-Sabatier-SPE integrated system were investigated. The experimental results from the SAWD unit showed that the average CO2 concentration in the CO2 storage tank was more than 96% and the outlet CO2 concentration was nearly zero in the first 45 min, and less than 1/10 of inlet CO2 after 60 min when input CO2 was 0.5% （1000 L）. About 950 L of CO2 was recovered with a recovery rate of 92%-97%. The output CO2 concentration was less than 0.2%, which showed that the adsorption-desorption performance of this unit was excellent. In the CO2 reduction unit we investigated mainly the start-up and reaction performance of the Sabatier reactor. The start-up time of the Sabatier reactor was 6, 8 and 10 rain when the start-up temperature was 187.3, 179.5 and 168 ℃, respectively. The product water was colorless, transparent, and had a pH of 6.9-7.5, and an electrical conductivity of 80μs/cm. The sum of the concentration of metal ions （Ru^3＋, Al^3＋, Pb^2＋） was 0.028% and that of nonmetal ions （Cl^-, SO4^2-） was 0.05%. In the O2 regeneration unit, the O2 generation rate was 0.48 m^3/d and the quantity was 2400 L, sufficient to meet the submariners＇ basic oxygen demands. These results may be useful as a basis for establishing CO2-1evel limits and O2 regeneration systems in submarines or similar enclosed compartments during prolonged voyages.
The development of multi-DOF prosthetic hand appeals for classfying more hand gestures based on myoelectric signals extracted from the forearm. Six surface electromyography (EMG) electrodes were used to acquire myoele...
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The development of multi-DOF prosthetic hand appeals for classfying more hand gestures based on myoelectric signals extracted from the forearm. Six surface electromyography (EMG) electrodes were used to acquire myoelectric signals. Each channel's sample means are used to constitute feature vectors for training the support vector machines (SVM). Then 19 modes of hand gestures can be discriminated effectively. Comparing with some traditional training methods that use the steady-state features of myoelectric signals, the new method improves the predicting accuracy both on full scale features and the ones between the mode transitions. This will benefit the on-line recognition of the hand gestures, therefore make the multi-DOF prosthetic hand's EMG control more intuitive and effective.
A kinematics model of the center of gravity (CG) position was set up based on the coordinate formula and robot kinematics. Then the change of CG in the process of climbing up an obstacle for tracked mobile robot was o...
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A kinematics model of the center of gravity (CG) position was set up based on the coordinate formula and robot kinematics. Then the change of CG in the process of climbing up an obstacle for tracked mobile robot was obtained by using this model, and the maximum height of the obstacle which can be climbed up was obtained. The margin of angle for stability was calculated. The relationship between the pitch angle of the robot and the height of the obstacle was obtained. From above analyses, the motion planning for climbing up the obstacle based on the margin of stability was presented. Experiments were conducted to verify the feasibility of established kinematics model and the motion planning.
Self-reconfigurable robots are different from other kinds of robots. The important difference is that these robots are self-reconfigurable based on their parts being intrinsically mobile. In order to give self-reconfi...
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Self-reconfigurable robots are different from other kinds of robots. The important difference is that these robots are self-reconfigurable based on their parts being intrinsically mobile. In order to give self-reconfigurable robots this ability, the authors conducted research using a structural features analysis of a DL-Cube module unit. On this basis a windmill-like meta-module (WLMM) was constructed. A design was made using the hierarchical planning method, on the basis of the WLMM, providing motion to the parts of the self-reconfigurable robot by a configuration that consists of WLMMs in the horizontal plane. At the same time, the WLMMs mobility allows changes to the azimuth of modules and the carrying of other modules. Thus the reconfiguration proceeds from an initial rectangular configuration to one that consists of 24 modules in an " H" configuration. Simulation experiments were given to prove the effectiveness of the hierarchical planning method and the feasibility of creating reconfigurability using WLMMs.
To realize the stable video feedback in the satellite self-servicing teleroboticssystem, a scheme based on scalable bit rate control is proposed. Delamination stream with different bit rates is selected according to ...
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To realize the stable video feedback in the satellite self-servicing teleroboticssystem, a scheme based on scalable bit rate control is proposed. Delamination stream with different bit rates is selected according to the bandwidth detected in real time. Therefore, the scheme is very suitable for web video transmitting service since it is adaptive to various bandwidth networks. The experimental results demonstrate that stable and smoothing video streams can be obtained by teleoperator even in various bandwidth conditions. Furthermore, the performance of visual telepresence is highly improved.
To overcome the high risk and cost of manned satellite servicing, a space robot arm is fixed on satellite body and a monocular camera is mounted on the arm to realize vision based satellite self servicing instead of t...
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To overcome the high risk and cost of manned satellite servicing, a space robot arm is fixed on satellite body and a monocular camera is mounted on the arm to realize vision based satellite self servicing instead of teleoperation. A new hybrid switching visual servo control is proposed following on-line calculation of object depth and pose to select PBVS or IBVS. By integrating some advantages of both methods, the trajectories of image and Cartesian space are controllable simultaneously. For wide range servo movement, especially rotation movement, PBVS is adopted, and for short distance servo movement IBVS is adopted. Thus, space robot of auto visual servo is realized in wide range. Taking account of space environment, cooperative object recognition has been designed and implemented. Therefore, servo features can be obtained quickly and stably in complex circumstances. Simulation and real experimental results demonstrate this approach is positioning accurate and robust for the measurements and the calibration errors as dealing with wide range visual servo.
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