基于差分进化算法的手眼标定方法

针对眼在手机器人视觉系统的手眼标定问题，提出了一种基于差分进化算法的手眼标定方法。首先建立了眼在手机器人视觉系统手眼标定的数学模型，通过李群李代数理论，将手眼标定问题转化为误差函数的优化问题，同时保证了优化问题的最优解落在特殊欧氏群ＳＥ（３）上。通过差分进化算法对优化问题进行求解，避免了求解过程中的局部最优问题。最后在实物平台上进行了手眼标定实验，实验结果验证了算法的可行性和有效性。     

A review on some classes of algebraic systems

ABSTRACT

In this paper, we review some algebraic control system. Precisely, linear and bilinear systems on Euclidean spaces and invariant and linear systems on Lie groups. The fourth classes of systems have a common issue: to any class, there exists an associated subgroup. From this object, we survey the controllability property. Especially, from those coming from our contribution to the theory.     

Investigation of alkaline complexant on ethanol synthesis from syngas over slurry CuZnAlOOH catalyst

A series of alkaline complexants promoted slurry CuZnAlOOH catalysts were prepared by a complete liquid-phase method. These catalysts were applied in a slurry bed reactor to selectively convert syngas into ethanol and higher alcohols (HAs). Herein, we showed that the addition of alkaline complexant remarkably enhanced both CO conversion and selectivity toward to ethanol and HAs in terms of ternary CuZnAlOOH catalyst. Besides, the formation of dimethyl ether (DME) was significantly suppressed. Interestingly, different from the traditional alkalis modified copper-based catalysts, these catalysts promoted by alkaline complexants mainly increased selectivity for ethanol, while not isobutanol. It also reduced the deactivation rate of the catalysts. These catalysts were comprehensively characterized by XRD, H₂-TPR, NH₃-TPD-MS, N₂ adsorption, FT-IR, XPS and TEM techniques. It was found that the increase of ethanol selectivity was related to the decrease of catalyst surface acidity, while the decrease of surface Cu⁺/(Cu⁰+Cu⁺) was regarded to the main reason for the catalysts deactivation. This paper showed that the introduction of alkaline complexants into Cu-based catalysts exhibited the potentiality to improve the stability and the yield of ethanol in a slurry bed reactor.     

Exponential Set-Point Stabilization of Underactuated Vehicles Moving in Three-Dimensional Space

This paper investigates the stabilization of underactuated vehicles moving in a three-dimensional vector space. The vehicle’s model is established on the matrix Lie group SE(3), which describes the configuration of rigid bodies globally and uniquely. We focus on the kinematic model of the underactuated vehicle, which features an underactuation form that has no sway and heave velocity. To compensate for the lack of these two velocities, we construct additional rotation matrices to generate a motion of rotation coupled with translation. Then, the state feedback is designed with the help of the logarithmic map, and we prove that the proposed control law can exponentially stabilize the underactuated vehicle to the identity group element with an almost global domain of attraction. Later, the presented control strategy is extended to set-point stabilization in the sense that the underactuated vehicle can be stabilized to an arbitrary desired configuration specified in advance. Finally, simulation examples are provided to verify the effectiveness of the stabilization controller.      

An element-free Galerkin forward solver for the complete-electrode model in electrical impedance tomography

An element-free Galerkin method (EFGM) is used for solving forward problem based on the complete electrode model (CEM) in electrical impedance tomography (EIT). The EFGM requires only nodal data and has the ability of providing mesh-independent solutions because no element connectivity is needed to be used in this method. However, direct imposition of Dirichlet boundary conditions for the EFGM is difficult because the shape functions employed in this method do not have the property of Dirac delta function. Solving the EIT forward problem based on the CEM by the EFGM, the effects of electrodes and contact impedances are taken into account and the complete solution of equations is provided without imposing Dirichlet boundary conditions. The numerical results are validated with experimental results obtained from a 2D circular homogeneous phantom, and the performance of the EFGM compared with the finite element method is also illustrated. Moreover, results obtained from the EFGM are presented for an inhomogeneous numerical phantom.     

带强迫项的KdV方程的非线性自伴随性和守恒律

应用非线性自伴随性的概念和伊布拉基莫夫的一般守恒律定理，研究了带强迫的KdV方程的非线性自伴随性和守恒律。首先讨论了自伴随性，结果表明这个方程具有非线性自伴随性，同时得到了这个方程的形式拉格朗日量。在对这个方程进行李对称分析之后，根据李对称的不同得到了这个方程的一些非平凡守恒律。     

Shorter Communication: Evaluating Tests for Increasing Intensity of a Poisson Process

The problem of testing the hypothesis of a constant intensity against the alternative of an increasing intensity function in a nonhomogeneous Poisson process is studied, and six wellknown tests are considered. Three of the six are shown to have desirable power-function properties, whereas the other three do not have the properties. In fact, the tests without the desirable properties should not be used, nor should any nonparametric test be used.     

Variational Bayesian data analysis on manifold

In this paper, variational inference is studied on manifolds with certain metrics. To solve the problem, the analysis is first proposed for the variational Bayesian on Lie group, and then extended to the manifold that is approximated by Lie groups. Then the convergence of the proposed algorithm with respect to the manifold metric is proved in two iterative processes: variational Bayesian expectation (VB-E) step and variational Bayesian maximum (VB-M) step. Moreover, the effective of different metrics for Bayesian analysis is discussed.     

运板车整车升降控制算法研究

通过对运板车自身特性的分析,以PID控制理论为基础,提出了具有长度和压力两套PID闭环的运板车整车升降控制算法,并通过试验,证明了该算法不但可以保证4个悬挂液压缸伸缩平稳同步,而且还可以保证所有悬挂液压缸不会因承载力不够而虚腿.     

Positively equicontinuous flows

Let G be a positively equicontinuous flow of homeomorphisms of a locally compact metric space E. We show how the dynamics of such a flow are rich. We study when regularly almost periodic elements in G are periodic and we describe orbits and their limit sets. In particular, we show that the limit set L(G?) of G is a closed subset on which G is equicontinuous and that if G moreover has closed orbits, then any w-limit set is a periodic orbit.