Applied Mechanics and Materials Vol. 394

Abstract: This paper discusses the problem of achieving stable walking of a compass gait biped robot on a slope. A reference trajectory for stable walking is generated using Lagrangian dynamics of the biped robot. It is shown that an underactuated robot can follow the reference trajectory using a control law based on feedback linearization with respect to both hip and ankle joints. The results are compared in terms of Mean Square Error (MSE). The validity of the proposed controller is carried out using simulation studies.

Abstract: Point-to-point reaching manual actions are present in numerous human-machine tasks. This is due to the fact that machines are commonly handled by a human operator through simple multiple interfaces. Therefore, task-performance evaluation methods based on extending the Fitts' law can be used as a skill estimator for the resulting human-machine system. This paper proposes a methodology for qualifying operator skill in point-to-point (p-t-p) man-machine operations, based on several task-performance index evaluation criteria. A 2-D real-time setup was built for the execution and evaluation of the p-t-p tracking experiences over a predefined process dynamics, using a pen tablet as the human-machine interface device. The analysis from the collected data reveals a correlation between operator performance and the fitting error to Fitts' law.

Abstract: In order to solve the attitude synchronization control problem for an on-orbit servicing spacecraft autonomous docking to a tumbling satellite in the presence of unknown bounded disturbances and system uncertainties, a compound control law is presented in this paper. The compound control law is composed of a nonlinear feedback control law and a compensate control law. The nonlinear feedback control law is mainly used to track the system command and the compensate control law is mainly used to deal with the external disturbances and system uncertainties to enhance the robustness of the control system. Simulation results verified the effectiveness of the designed compound control law, and the robustness to the unknown bounded disturbances, system uncertainties is also demonstrated.

Abstract: To meet the demand of rotating mechanism for self-powered monitoring system, piezoelectric energy generator (PEG) excited by the magnetic coupling force between rotating magnets fixed on a rotator and those fixed on piezo-beam was presented. The influence of magnetic force (number and configuration of the magnets) and rotating speed on energy generation of the PEG was investigated experimentally. The research results show that there are several optimal rotating speeds for the PEG to achieve peak voltage at speed range of 0 to 1390r/min. Under a given number of magnets fixed on the end of the piezo-beam, the peak voltages rise with the increasing of rotating magnets number and rotating speed. At 636r/min, the achieved peek voltages from the PEG with 1/2/4 rotating magnets are 12.1/15.2/20.0V respectively. Besides, the configuration modes of rotating magnets and the fixed magnets (repulsion, attraction, or repulsion-attraction) exert great influence on the peak voltage and the relative optimal rotating speeds. Taking a PEG with 2 rotating magnets for example, the 4th peek voltages and the relative optimal rotating speeds for the PEG under exciting mode of repulsion/attraction//repulsion-attraction are 12.6/15.0/16.4 V and 552/528/492 r/min respectively.

Abstract: Extracting an electrical energy from various environmental sources, called energy harvesting (or energyscavenging), has been an issue and attracting researchers attention in energy replenish networks.Thermal energy harvesting holds a promising future for generatinga small amount of electrical power to drive partial circuits in wirelessly communicatingelectronics devices. Reducing power consumption has also become a major challenge in wireless body area network (WBAN). The reliability ofthe WBAN is greatly dependent on the life span of theenergyaware routing in networks.In this paper presented a fuzzy controller for thermal energyaware routing in WBAN.The paper concludes with performance analysis of the thermal energy harvesting aware routing, comparison of fuzzy and other traditional energy management techniques,while also looking at open research areas of thermoelectric harvesting and management for wireless body area networks.

Abstract: The recent ISO/IEEE 11073 PHD standard presented a way to achieve the communication between personal healthcare devices, but it didnt specified how to interact with the other smart homes component. The paper designed an interaction model composed of three kinds of service pack and signal-slot mechanism, the model provided a simple way to identify the device status and manage x73 messages. And it did an experiment about R wave detection to verify the interaction model successfully. The paper promotes the application of x73 standard in the interaction between healthcare devices and the other smart homes component.

Abstract: Operating Linux Application softwares on Windows platform, can not only promote the development of interoperability technology of these two operating systems, but also strengthen the status Windows has in the market. Because of the differences in the architectures of Linux and Windows, when running Linux application programs in Windows operating system, we need to resort to some certain kinds of technologies such as Services For Unix, Application Programming Interface emulation, virtual machine platform, source codes refactoring, etc. This paper aims at making deep analyses on the principles and features of these technologies.

Abstract: In this paper the performance of LT codes is analyzed. And then, for the remaining part of information which can be decoded still exists when decoding failure, an improved message passing decoding algorithm which retains the original algorithm framework is proposed. The simulation results have shown that the improved message passing decoding algorithm improves the decoding rate and reduces decoding overhead on the premise of appropriately increasing decoding complexity.

Abstract: This paper presents an improved particle swarm optimization (PSO) algorithm based on genetic algorithm (GA) and Tabu algorithm. The improved PSO algorithm adds the characteristics of genetic, mutation, and tabu search into the standard PSO to help it overcome the weaknesses of falling into the local optimum and avoids the repeat of the optimum path. By contrasting the improved and standard PSO algorithms through testing classic functions, the improved PSO is found to have better global search characteristics.

Abstract: For over 40 years, the universal soil loss equation (USLE) and its revised version the revised universal soil loss equation (RUSLE) have been used all over the world for soil mean annual loss per area unit. Because of the watershed erosion models are under developing, many researchers applied the USLE and RUSLE to estimate soil loss in watershed estimations. However, a major limitation is the difficulty in extracting the LS factor. The geographic information system-based (GIS-based) methods which have been developed for estimating the slope length for USLE and RUSLE model also have limitations. A series of ARC/INFO AML program was created that can calculate LS factor for the USLE, however the program need a very long time to run in wide-ranging areas. The flowpath and cumulative cell length-based method (FCL) overcomes this disadvantage but does not consider the following questions: (1) Some original AML program functions are not achieved, so results are different. (2) Using USLE to calculate LS factor that do not adapt to the erosion environment of China. (3) There isnt a friendly graphic user interface. The purpose of this research was to overcome these limitations and extend the FCL method through Integrating CSLE equation. We developed a LS calculation tool (LS-TOOL) in Microsofts .NET environment using C# with a user-friendly interface. Comparing the LS factor calculated with the FCL method and AML method, LS factor values generated by using LS-TOOL method delivers improved results. The LS-TOOL algorithm can automatically calculate slope length, slope steepness, L factor, S factor, and LS factors, providing the results as ASCII files which can be easily used in some GIS software. This study is an important step forward in conducting fast large-scale erosion evaluation.