摘要: 设计一种液压四足机器人仿生机构,通过设定相应的坐标系为机器人进行运动学建模,并对行走过程中单腿的相位关系进行了分析。针对行走过程中足端的拖地、滑动和接触冲击等问题,提出一种零冲击的足端轨迹规划改进算法,并实现了步态规划算法设计。步态规划根据步态中各腿间的相位关系,借助四足机器人运动学模型进行逆运动学解算,求出各腿的关节角度函数,利用机构的几何关系得到各液压缸伸缩量控制函数,对试验样机各腿进行伺服驱动控制,从而实现液压四足机器人的步态规划行走。仿真试验结果表明,在该策略驱动控制下液压四足机器人行走过程连续平稳,样机足端轨迹较为平滑,躯干起伏较小,证明了该足端轨迹规划方法用于四足机器人步态设计的合理性和有效性。

Porous ZnO nanosheets exhibit superior sensitivity in ethylene detection and present different intensity responses to bananas at maturity stages.

In this paper, we propose a regression model to establish relationship between surface electromyography (sEMG) and knee joint angles. model, the correlation dimension of wavelet coefficient (WCCD) an Elman network are developed for estimation. our experiment, sEMG signals were recorded from five muscles concerned with motion, angles simultaneously by Codamotion system. First, used feature extraction method based on WCCD extract optimal vectors multichannel signals. Then, was map features The...

Many people lose their motor function because of spinal cord injury or stroke. This work studies the patient’s continuous movement intention joint angles based on surface electromyography (sEMG), which will be used for rehabilitation. In this study, we introduced a new sEMG feature extraction method wavelet packet decomposition, built prediction model extreme learning machine (ELM) and analyzed correlation between signals detrended cross-correlation analysis. Twelve individuals participated...

In order to investigate the kinetic mechanism of thermal decomposition poplar sawdust, thermogravimetric experiments were performed using a analyzer. The results showed that activation energy varied from 17.64 kJ/mol 161.14 kJ/mol. pre-exponential factor values indicated empirical first-order reaction. Gibbs free 127.88 223.55 kJ/mol, and entropy changes negative. calorific value biomass was 19,482 kJ/kg.

Piezoelectric films have been demonstrated to be attractive for micromechanical systems (MEMS) devices. Among the piezoelectric used, AlN film has less explored. In this study, resonators and accelerometers, utilizing longitudinal transverse effects respectively, were demonstrated. Resonators with Q of 1000 electromechanical coupling (k <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">t</sub> <sup...

Separating induction motor noise sources can provide an important reference basis for condition detection, reduction treatment, and fault diagnosis. Induction motors have different types of that partially overlap, most radiate outward through the housing, so it is difficult to separate these sources. Therefore, a single-channel source separation identification method, based on adaptive scale-space modal extraction (ASSME) proposed. Firstly, mode method proposed by constructing...

The dynamics and stability of passive bipedal robot have an important impact on the mass distribution, leg length, angle inclination. Lyapunov’s second method is difficult to be used in highly nonlinear multibody systems, due lack constructive methods for deriving Lyapunov fuction. equation established by Kane method, relationship between mass, length leg, inclination, largest exponent. And exponents continuous dynamical systems are estimated numerical methods, which simple easy applied...

Views Icon Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Twitter Facebook Reddit LinkedIn Tools Reprints and Permissions Cite Search Site Citation Li-Peng Wang, Dong S. Shim, Qing Ma, Valluri R. Rao, Eyal Ginsburg, Alexander Talalyevsky; Characterization of polycrystalline AlN films using variable-angle spectroscopic ellipsometry. Journal Vacuum Science Technology A 1 July 2005; 23 (4): 1284–1289. https://doi.org/10.1116/1.1875192 Download citation file:...

The influence of magnetic fields lasers on the generation terahertz radiation by an interaction between two-color and plasmas is investigated from theoretical analysis particle-in-cell simulation. Analytical expressions field for both laser propagation direction polarization in presence are obtained. It found that only have a contribution or enhancement direction, while it has no direction. feasibility result validated through This investigation shows effect must be considered. Moreover,...

In various practical noise control scenarios, such as duct mitigation, industrial machinery, architectural acoustics, and underwater applications, it is essential to develop absorbers that deliver effective low-frequency attenuation while maintaining compact dimensions. To achieve absorption within a limited spatial volume, this study proposes an embedded Helmholtz resonator featuring roughened neck establishes numerical computational model incorporates thermos viscous effects. A...

We report experimental results of a novel approach to integrate multiple-frequency film bulk acoustic resonators (FBAR) in single chip. An additional tuning layer was deposited and patterned on conventional Metal/AlN/Metal FBAR stack. By controlling in-plane dimensions the periodic patterns, resonance frequencies are modulated according corresponding loading percentages. To obtain desirable frequency response peaks (a pure shift), pitch patterns needs be smaller than membrane thickness....

Efficient heat transfer is still one of the major concerns to be solved in battery thermal management technology. This paper proposes a method based on silicon oil. With this method, pack totally immersed oil, through which generated during dis/charging dissipated. To evaluate performance proposed electrochemical-thermal coupling model lithium with 12 50Ah cells series established, electrical and simulated. The results show when discharging at 1C rate, overall temperature oil 0.5 °C lower...