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ABSTRACT Lagrangian analysis method derives the specific internal energy, strain, and stress and particle velocity histories from either stress or particle velocity records from a series of gauges embedded in [...]

In recent years, the number of the damage bridge due to excessive deformation gradually increased, which caused significant property damage and casualties. Hence health monitoring and the damage detection of the bridge structure based on the deflection measurement are particularly important. The current conventional deflection measurement methods, such as total station, connected pipe, GPS, etc., have many shortcomings as low efficiency, heavy workload, low degree of automation, operating frequency and working time constrained. GPS has a low accuracy in the vertical displacement measurement and cannot meet the dynamic measured requirements of the current bridge engineering. This paper presents a bridge health monitoring and damage detection technology based on digital image measurement method in which the measurement accuracy is sub-millimeter level and can achieve the 24-hour automatic non-destructive monitoring for the deflection. It can be concluded from this paper that it is feasible to use digital image measurement method for identification of the damage in the bridge structure, because it has been validated by the theoretical analysis, the laboratory model and the application of the real bridge.

As an autonomic and convenient assistance device for people with disabilities and the elderly climbing up and down stairs, electric-powered wheelchairs with stair-climbing ability have attracted great attention in the past two decades and some various electric-powered wheelchairs with stair-climbing were developed. By using the developed electric-powered wheelchairs with stair-climbing, many patients with walking difficulties are able to descend the stairs conveniently to participate in outdoor activities, which are beneficial to both their physical rehabilitation and mental health. In this article, a review of electric-powered wheelchair with stair-climbing current technology is given and its future tendency is discussed to inform electric-powered wheelchair with stair-climbing researchers in the development of more applicable and popular products. Firstly, the development history is reviewed and electric-powered wheelchairs with stair-climbing are classified based on an analysis of their stair-climbing mechanisms. The respective advantages and disadvantages of different types of electric-powered wheelchairs with stair-climbing are outlined for an overall comparison of the control method, cost of mechanical manufacture, energy consumption, and adaption to different stairs. Insights into the future direction of stability during stair-climbing are discussed as it is an important aspect common to all electric-powered wheelchairs with stair-climbing. Finally, a summary of electric-powered wheelchairs with stair-climbing discussed in this article is provided. As a special review to the electric-powered wheelchairs with stair-climbing, it can provide a comprehensive understanding of the current technology about electric-powered wheelchairs with stair-climbing and serve as a reference for the development of new electric-powered wheelchairs with stair-climbing.

Aiming at the functional requirement of climbing up the stairs, the dynamics and stability during a tracked mobile robot's climbing of stairs is studied. First, from the analysis of its cross-country performance, the mechanical structure of the tracked mobile robot is designed and the hardware composition of its control system is given. Second, based on the analysis to its stairs-climbing process, the dynamical model of stairs-climbing is established by using the classical mechanics method. Next, the stability conditions for its stairs-climbing are determined and an evaluation method of its stairs-climbing stability is proposed, based on a mechanics analysis on the robot's backwards tumbling during the stairs-climbing process. Through simulation and experiments, the effectiveness of the dynamical model and the stability evaluation method of the tracked mobile robot in stairs-climbing is verified, which can provide design and analysis foundations for the tracked mobile robots' stairs-climbing.