倒立摆系统的运动模态分析

提出倒立摆系统在受控稳定状态下的运动模态概念 .通过对倒立摆系统物理结构的分析 ,归纳出由单电机控制的单倒立摆、二级倒立摆和三级倒立摆系统在受控稳定状态下可能出现的主要运动模态 .在以数控方式实现由单电机成功控制单倒立摆、二级倒立摆和三级倒立摆系统稳定的基础上 ,分析控制倒立摆系统稳定的控制律反馈增益系数与系统稳定运动模态之间存在的关系 .

矿山探测机器人移动平台设计与越障机理研究

为提升机器人在矿山非结构复杂地面环境的通过性能,设计并研发了摆臂式侦察机器人。基于机器人移动平台,对机器人进行了动力学建模。针对机器人移动平台摆臂模块进行了越障机理和运动模态研究,分析了机器人越障高度与机器人几何参数的关系,并对前后摆臂组件辅助下的机器人最大越障高度进行了分析研究。理论研究表明机器人最大越障高度463mm,与现场实测越障高度467mm误差小于1%,实验结果验证了理论分析的有效性,研究结果有利于机器人环境感知下的自动越障控制和智能化侦察。

Damping Identification of Bridges Under Nonstationary Ambient Vibration

This research focuses on identifying the damping ratio of bridges using nonstationary ambient vibration data. The damping ratios of bridges in service have generally been identified using operational modal analysis （OMA） based on a stationary white noise assumption for input signals. However, most bridges are generally subjected to nonstationary excitations while in service, and this violation of the basic assumption can lead to uncertainties in damping identification. To deal with nonstationarity, an amplitude-modulating function was calculated from measured responses to eliminate global trends caused by nonstationary input. A natural excitation technique （NExT）-eigensystem realization algorithm （ERA） was applied to estimate the damping ratio for a stationarized process. To improve the accuracy of OMA-based damping estimates, a comparative analysis was performed between an extracted stationary process and nonstationary data to assess the effect of eliminating nonstationarity. The mean value and standard deviation of the damping ratio for the first vertical mode decreased after signal stationarization.

Validation of a Marker Model for Gait Analysis with Wearable Exoskeletons

The aim of the present study was to develop and validate a new marker model for optoelectronic systems adapted to wearable devices, in order to have an analysis tool for kinematic gait evaluation of reproduced patterns by exoskeletons. The marker model has a total of 36 retro-reflective markers attached bilaterally to anatomical landmarks during the static measures （without exoskeleton） and 28 markers at the dynamics measures （with exoskeleton）. The main difference between others kinematic models and the described adapted model was the placement of the three markers in the back thigh and the other three in the back calf, what allowed removing the hip, thigh, knee, tibia and ankle markers. The proposed adapted marker model could be an effective tool to validate the joint movement and velocities of those wearable exoskeletons that at present have been developing.

Development of XY scanner with minimized coupling motions for high-speed atomic force microscope

The design and fabrication processes of a novel scanner with minimized coupling motions for a high-speed atomic force microscope （AFM） were addressed. An appropriate design modification was proposed through the analyses of the dynamic characteristics of existing linear motion stages using a dynamic analysis program, Recurdyn. Because the scanning speed of each direction may differ, the linear motion stage for a high-speed scanner was designed to have different resonance frequencies for the modes, with one dominant displacement in the desired directions. This objective was achieved by using one-direction flexure mechanisms for each direction and mounting one stage for fast motion on the other stage for slow motion. This unsymmetrical configuration separated the frequencies of two vibration modes with one dominant displacement in each desired direction, and hence suppressed the coupling between motions in two directions. A pair of actuators was used for each axis to decrease the crosstalk between the two motions and give a sufficient force to actuate the slow motion stage, which carried the fast motion stage, A lossy material, such as grease, was inserted into the flexure hinge to suppress vibration problems that occurred when using an input triangular waveforrn. With these design modifications and the vibration suppression method, a novel scanner with a scanning speed greater than 20 Hz is achieved.

The obstacle crossing ability analysis and improvement of the cable inspection robot

In this paper, the climbing obstacle capability of the previous special cable inspection robot （ Model Number： XS1T-1） is analyzed. Static equations are established to analyze the relationships between the external forces and the maximum height of an obstacle. Parameters affecting the obstacle crossing ability are obtained. According to the analysis results, an innovated small volume, simple structure and light weight climbing mechanism is proposed （Model Number： XS1T-2）. A simplified kinematics model of the mechanism is established. With two powered wheels, the obstacle crossing ability of the XSIT-2 is improved apparently. For the robot moving without deflection, the relationships of two powered input torques are deduced. The comparison of the simulation results clearly shows that the climbing ability of XS1T-2 is obviously improved, and it can meet the demands of inspection.

Simulation of Sliding Failure Occurred at Highway Embankment in 2011 Great East Japan Earthquake

In the 2011 Great East Japan Earthquake, the highway embankments were almost less damaged comparing with the past earthquakes in Japan. But the only one embankment close to the Naka Interchange at Joban Highway was damaged a little severely and remarkably because of two interesting phenomena. One phenomenon is the toe-sliding failure observed at the shallow soft base ground and the other one is one-side slope sliding failure. It can be seen that the increase in the degree of saturation at embankment body or the direction of the ground motion or the interaction between the strength of the base ground and the embankment body are involved in the stability of the embankment by modifying the phenomenon by analytical approach such as circular sliding method and dynamic response analysis. Through this research, some important lessons can be obtained for future seismic countermeasure of embankments.

An improvement to the reciprocating gait orthosis for aiding paraplegic patients in walking

As the conventional reciprocating gait orthosis(RGO)has been deemed incapable of facilitating the patients’passive movement with significant gait discrepancies and distortion,in addition to characteristics such as poor stability,and negligible knee joint rehabilitation,a power assisted reciprocating gait orthosis(PARGO)was designed.Drive devices were added to the hip and knee joints of the RGO.Through efficient implementation of structural components,the number of the required motors was reduced,therefore decreasing the weight of the orthosis.The PARGO knee joint’s structural principle was analyzed to characterize the effect of the PARGO’s single-axis knee joint design on wear comfort,thereby providing a basis for the wear of the PARGO.By analyzing the sagittal movement patterns of the hip and knee joints during normal human gait,kinematic analysis was carried out to obtain the input patterns of the PARGO hip and knee joint drive motors,enabling the patients to more accurately reproduce the normal gaits of hip and knee joints during the rehabilitation training with the aid of the PARGO,and the control process of the PARGO was studied.Finally,a prototype of the PARGO was developed,and experimentation was carried out to demonstrate the feasibility of the improved orthosis.