滚动轮胎摩擦和制动特性的试验及数值模拟研究

轮胎模拟是当今轮胎行业技术研究的一项必要手段。汽车制造商、政府部门和消费者要求轮胎在任何情况下都具有更好的牵引性能和更低的磨耗,还要求轮胎有更低的噪声和滚动阻力。因此,在轮胎设计过程中采用有限元分析来解决这     

Definition of requirements for accessing multilingual information opinions

Multimedia Tools and Applications - In this paper, we will present a study concerning the understanding of the needs of people using Internet in order to access to multilingual information. In...     

Equivalence of nonlinear systems to triangular form: the singular case

The problem of state equivalence of a given nonlinear system to a triangular form is considered here. The solution of this problem has been known for the regular case, i.e. when there exists a certain nested sequence of regular and involutive distributions. It is also known that in this case the corresponding system is linearizable using a smooth coordinate change and static state feedback. This paper deals with the singular case, i.e. when the nested sequence of involutive distributions of the system contains singular distributions. Special attention is paid to the so-called bijective triangular form. Geometric, coordinates-free criteria for the solution of the above problem as well as constructive, verifiable procedures are given. These results are used to obtain a result in the nonsmooth stabilization problem.     

A virtual structure approach to formation control of unicycle mobile robots using mutual coupling

In this article, the formation control problem for unicycle mobile robots is studied. A distributed virtual structure control strategy with mutual coupling between the robots is proposed. The rationale behind the introduction of the coupling terms is the fact that these introduce additional robustness of the formation with respect to perturbations as compared to typical leader–follower approaches. The applicability of the proposed approach is shown in simulations and experiments with a group of wirelessly controlled mobile robots.     

A high-vacuum deposition system for in situ and real-time electrical characterization of organic thin-film transistors

We present a home-built high-vacuum system for performing organic semiconductor thin-film growth and its electrical characterization during deposition (real-time) or after deposition (in situ). Since the environment conditions remain unchanged during the deposition and electrical characterization process, a direct correlation between growth mode and electrical properties of thin film can be obtained. Deposition rate and substrate temperature can be systematically set in the range 0.1-10 ML∕min and RT-150 °C, respectively. The sample-holder configuration allows the simultaneous electrical monitoring of up to five organic thin-film transistors (OTFTs). The OTFTs parameters such as charge carrier mobility μ, threshold voltage V(TH), and the on-off ratio I(on)∕I(off) are studied as a function of the semiconductor thickness, with a submonolayer accuracy. Design, operation, and performance of the setup are detailed. As an example, the in situ and real-time electrical characterization of pentacene TFTs is reported.     

Synchronization Control for a Swarm of Unicycle Robots: Analysis of Different Controller Topologies

This paper proposes a nonlinear synchronization controller for a swarm of unicycle robots performing a cooperative task, i.e., following a desired trajectory per robot while maintaining a prescribed formation. The effect of communication between robots is analyzed and several network topologies are investigated, e.g., all‐to‐all, ring type, undirected, among others. The stability analysis of the closed loop system is provided using the Lyapunov method. Experiments with four unicycle robots are presented to validate the control law and communication analysis. Accumulated errors over the experiment time are presented in order to determine which topology is most efficient.     

Flutter and bifurcation instability analysis of fluid-conveying micro-pipes sandwiched by magnetostrictive smart layers under thermal and magnetic field

International Journal of Mechanics and Materials in Design - Fluid-conveying micro/Nano structures are key tools in MEMS and NEMS applications especially for drug delivery systems to attack a...     

Prediction of chaotic behavior

This paper considers the prediction of chaotic behavior using a master-slave synchronization scheme. Based on the stability theory for retarded systems using a Lyapunov-Krasovskii functional, we derive a sufficient condition for perfect state prediction of the master system via a time-delayed output signal of the slave system. The obtained result is based on the delay-dependent stability of time-delay systems. In addition, we derive an upper bound of the admissible time delay by using linear matrix inequality techniques. Finally, we show the effectiveness of the proposed predictor by two numerical examples.