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A planar passive walking model with straight legs and round feet was discussed. This model can walk down steps, both on stairs with even steps and with random steps. Simulations showed that models with small moments of inertia can navigate large height steps. Period-doubling has been observed when the space between steps grows. This period-doubling has been validated by experiments, and the results of experiments were coincident with the simulation. 相似文献
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The physical posture of even healthy university students is easy to collapse when walking with textbooks and other heavy loads during university attendance. Consequently, they may experience lower-back pain or knee pain. However, the resulting burden of this stress to the left and right lower-back has not previously been quantitatively analyzed.In this study, we employed a Relative Power Contribution (RPC) analysis approach to quantitatively investigate and compare the reciprocal contribution between the left and right lower-backs while walking with a bag and without a bag. Quantitative data were collected by two accelerometers installed on the subjects.Results for the subjects walking with and without a bag indicated that the contribution of the left and right lower-backs decreased by up to 21% (p<0.05). Some disorder occurs in the feedback relations of the movement in both lower-backs and as a result, it was understood to cause much discomfort in these areas.This analysis reveals the quantitative relations of left and right lower-backs, which are difficult to discern from the original data. The results can be useful for preventive healthcare for lower-back and knee pains. 相似文献
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Jing Sun Xiaoning Li Liu Huang Xin Liu Jiyu Liu 《Journal of Dispersion Science and Technology》2013,34(12):1840-1847
AbstractAquatic microrobots, which can walk freely on water mimicking water striders, have attracted considerable interest among scientists in biomimetic area. Most of previous water strider robots adopted gear pairs as their driving mechanism, which called for high assembly precision and thereby increased the processing difficulty. Here, a novel and simple method using servos as the driving module to prepare water walking robot was proposed. We fabricated this robot by using supporting and actuating legs with excellent superhydrophobicity. Our robot weighted 27.9?g, but could float and run quickly driven by mini-type servos under remote Bluetooth control in mobile terminal. The legs were obtained on Al substrates by chemical etching, boiling-water immersion and low surface energy modification. Then, surface morphology and chemical compositions were subsequently investigated by SEM, EDS and XRD. In order to better illustrate the floating and rowing mechanism of this robot on the water surface, mechanics analysis models were proposed to analyze the lifting force and resistance force, respectively. Due to its excellent floating capacity and rowing ability, the biomimetic robot has promising application potential in water quality monitoring, aquatic exploration, and other surveillance missions. 相似文献
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Quantum walk (QW), which is considered as the quantum counterpart of the classical random walk (CRW), is actually the quantum extension of CRW from the single-coin interpretation. The sequential unitary evolution engenders correlation between different steps in QW and leads to a non-binomial position distribution. In this paper, we propose an alternative quantum extension of CRW from the ensemble interpretation, named quantum random walk (QRW), where the walker has many unrelated coins, modeled as two-level systems, initially prepared in the same state. We calculate the walker's position distribution in QRW for different initial coin states with the coin operator chosen as Hadamard matrix. In one-dimensional case, the walker's position is the asymmetric binomial distribution. We further demonstrate that in QRW, coherence leads the walker to perform directional movement. For an initially decoherenced coin state, the walker's position distribution is exactly the same as that of CRW. Moreover, we study QRW in 2D lattice, where the coherence plays a more diversified role in the walker's position distribution. 相似文献