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Li T.,Beijing Institute of Technology | Li T.,North China Electrical Power University | Yu Z.,Beijing Institute of Technology | Yu Z.,North China Electrical Power University | And 13 more authors.
2014 IEEE International Conference on Robotics and Biomimetics, IEEE ROBIO 2014 | Year: 2014

This paper presents a control strategy based on phase modification during double support period to enhance a humanoid robot's walking stability. When the foot of the swing leg touches the ground, if Zero Moment Point(ZMP) is not in the stable margin, the phase modification will start. According to the position of ZMP and the relationship between the motion of Center of Gravity(COG) and ZMP position, the related parameters are solved. Series of experiments are taken, and the effectiveness of the method is validated repeatedly. © 2014 IEEE. Source

Jin D.,Tsinghua University | Deng B.,CAS Institute of Electronics | Li J.X.,Tsinghua University | Cai W.,North Navigation Control Technology Co. | And 4 more authors.
Biomicrofluidics | Year: 2015

Single cell trapping increasingly serves as a key manipulation technique in single cell analysis for many cutting-edge cell studies. Due to their inherent advantages, microfluidic devices have been widely used to enable single cell immobilization. To further improve the single cell trapping efficiency, this paper reports on a passive hydrodynamic microfluidic device based on the "least flow resistance path" principle with geometry optimized in line with corresponding cell types. Different from serpentine structure, the core trapping structure of the micro-device consists of a series of concatenated T and inverse T junction pairs which function as bypassing channels and trapping constrictions. This new device enhances the single cell trapping efficiency from three aspects: (1) there is no need to deploy very long or complicated channels to adjust flow resistance, thus saving space for each trapping unit; (2) the trapping works in a "deterministic" manner, thus saving a great deal of cell samples; and (3) the compact configuration allows shorter flowing path of cells in multiple channels, thus increasing the speed and throughput of cell trapping. The mathematical model of the design was proposed and optimization of associated key geometric parameters was conducted based on computational fluid dynamics (CFD) simulation. As a proof demonstration, two types of PDMS microfluidic devices were fabricated to trap HeLa and HEK-293T cells with relatively significant differences in cell sizes. Experimental results showed 100% cell trapping and 90% single cell trapping over 4 × 100 trap sites for these two cell types, respectively. The space saving is estimated to be 2-fold and the cell trapping speed enhancement to be 3-fold compared to previously reported devices. This device can be used for trapping various types of cells and expanded to trap cells in the order of tens of thousands on 1-cm2 scale area, as a promising tool to pattern large-scale single cells on specific substrates and facilitate on-chip cellular assay at the single cell level. © 2015 AIP Publishing LLC. Source

Xu Z.,Beijing Institute of Technology | Gao J.,Beijing Institute of Technology | Chen J.,North Navigation Control Technology Co.
4th Annual IEEE International Conference on Cyber Technology in Automation, Control and Intelligent Systems, IEEE-CYBER 2014 | Year: 2014

The coal robot is highly demanded in rescuing and detecting in the coal tunnel after explosion. Due to combustible gases in the tunnel, brushless direct current motor is widely applied for avoiding the danger of spark. In addition, the brushless direct current motor adapts to flexible load, which makes it satisfy both the tough terrain and the slopes. In this paper, the wheeled robot is developed in the Adams. The brushless direct current motor control system is modeled precisely based on the Matlab Simulink and Adams S-function to test the slope climbing ability. To enhance the performance of the speed tracking capacity, a hybrid fuzzy speed controller composed of fuzzy logic controller and proportion integration differential controller is proposed. The simulations show that the controller with a constant set of coefficient cannot adapt to both level road and slope. The results indicate that the motor control system based on the hybrid fuzzy speed controller regulates the speed and torque very well. Therefore, the motor control system is capable of fulfilling the speed tracking under flexible load. Additionally, the results show that the motor and reducer can meet the needs of the maximum torque and the power supplement. © 2014 IEEE. Source

Jiang W.J.,National University of Defense Technology | Jiang W.J.,Hunan University of Commerce | Xu Y.S.,North Navigation Control Technology Co. | Guo H.,North Navigation Control Technology Co. | Zhang L.M.,Wuhan University
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2015

At present, all kinds of malicious acts appear in C2C online auctions, particularly the phenomenon of trust lack and credit fraud is very outstanding. Therefore, how to build an effective trust model has become a burning problem. Based on analyzing limitations of the existing online trust transaction mechanism, and according to characteristics (such as dynamic, innominate and suppositional) of online transaction trust problem, the article proposes a dynamic trust calculation model and reputation management mechanism of online trading based on multi-Agent system.. The model consists of three parts. The first part is the trust of user domain, to put importance on the influence on current trust by recent credibility status, to motivate users to adopt a agreed cooperative strategy. The second part is the weighted average of reputation feedback score, The weighted part mainly considers the trust from the reputation feedback score person (the credibility of the feedback score), the value of the transaction (to prevent the “credit squeeze”), temporal discounted (“guard against the fluctuations of the credibility”) and other factors; the third part is to give a weighting on the community contribution, according to the action taken by a user to the other members of the community in a time domain, to increase or decrease the user’s trust to isolate the feedback submission of the credibility and punish the fraud. The paper builds the fraud limition mechanism which combine the prevention beforehand, coordination in the event and punishement afterwards. The mechanism makes the online transaction safe. Theoretic proof and experimental verification indicate the following three problems can be solved effectively: 1) solving the problem which is difficult to prevent and is that peculative user accumulates the little trusts and squeeze on the large trading; 2) preventing members from cheating by false trading or personation; 3) reducing the arbitration workload of the online business platform. © Springer International Publishing Switzerland 2015. Source

Fu S.-Y.,Central University of Costa Rica | Han L.-W.,North Navigation Control Technology Co. | Tian Y.,North Navigation Control Technology Co. | Yang G.-S.,Central University of Costa Rica
Proceedings of the 11th IEEE International Conference on Cognitive Informatics and Cognitive Computing, ICCI*CC 2012 | Year: 2012

Path planning has always been a crucial issue for UAV. The UAVs path planning in multiple missions involves the solution of an optimization problem. Genetic algorithms (GAs) are well applied to solve such problems as a stochastic search method. In this paper, a new method based on genetic algorithm is presented to generate path for UAV in the existence of unknown obstacle environments. The path planning model is based on 2D digital map, and an adaptive evolutionary planner is adopted based on a set of criteria to generate path online to avoid being detected by ground surveillance radar sites. Simulation studies are carried out to verify the effectiveness of the proposed algorithm. We believe the GA algorithm may be of help in the future reseach direction of UAV path planning problem. © 2012 IEEE. Source

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