Passive compliance for a RC servo-controlled bouncing robot

A novel and low-cost passively compliant mechanism is described that can be used with RC servos to actuate legged robots in tasks involving high dynamic loads such as bouncing. Compliance is achieved by combining visco-elastic material and metal parts. Joint response to dynamic loads is evaluated using real-world experiments and force data are obtained from a Lagrangian analysis of the system. The experimental results demonstrate the applicative potential of this mechanism.     

Design and Realization of a Non-Circular Cable Spool to Synthesize a Nonlinear Rotational Spring

In this paper we present a cable mechanism that realizes a nonlinear rotational spring from a linear translational spring. The spring is pulled by a cable wound around a non-circular spool, which is rigidly attached to the joint. The non-circular shape of the spool induces a nonlinear relationship between its angular position and the torque created by the tension of the cable. Depending on the shape of the spool, various torque–angle relationships can be realized. We show that for a given nonlinear torque–angle relationship, there is an explicit expression (closed-form solution) of the shape of the spool that synthesizes this function. First, we present the geometry of the problem. Then, we derive the methodology to calculate the shape of the spool to synthesize a prescribed torque–angle relationship. Finally, we verify the design methodology by experiments with three different spools realizing a constant force spring, an exponential softening spring and a cubic polynomial spring. We discuss the possible sources of errors between the theoretical and experimental results.     

论钢铁企业信息化项目的沟通管理

文中以太钢测量设备信息管理系统的开发为例,结合作者实践,讨论在钢铁企业信息化项目进行沟通管理的问题。该项目作为太钢信息化建设的重要组成部分,由测量设备台账管理、周检计划、检定校准流程管理和业务变更流程管理4个模块组成,系统采用STRUTS＋SPRING＋IBATIS主流WEB应用框架,结合ORACLE10G数据库完成系统开发工作。     

SPRING-Maven框架下基于RMI的分布式应用

RMI作为Java所支持的远程调用方法,被广泛应用于分布式系统开发。本文介绍了JavaRMI的特点,以及在SPRING—Maven框架下RMI开发分布式应用的主要步骤,并以Account系统为例,简要说明了RMI远程对象访问、远程方法调用的原理和实现过程。     

Comparison of various balance systems for energy conservation in a vertically articulated manipulator with three joints

It is important to conserve dissipated energy from machines in order to reduce global warming. This paper discusses energy conservation in a vertically articulated three-joint manipulator with a rotation–pivot–pivot structure. The amount of dissipated energy can be decreased by canceling out the gravity on the second and the third links of the manipulator using a mass balancer or a spring balancer. Mass balancers are designed optimally by diminishing the inertia matrix so that the amount of dissipated energy can be minimized. Three kinds of counterbalancer systems, which include a mass–mass balancer, a spring–mass balancer and a spring–spring balancer, are designed optimally. Energy is compared among the three types of counterbalancers mounted on a three-link manipulator in simulation. The simulation indicates that a spring–mass balancer is more practical because of the considerable energy conservation effect and simplicity in implementation. In order to confirm the simulation results, the dissipated energy is measured experimentally using a practical system of a directly-driven manipulator on which a suboptimal mass–mass balancer or a spring–mass balancer is mounted. As a result, the measured dissipated energy is approximately the same as the result obtained by simulation.     

Study on cascaded whole-leaf spring oscillation mechanism for mould in continuous casting

Abstract

A design method of a cascaded whole-leaf spring mechanism is proposed, which is a new oscillation guidance device for the mould in continuous casting. Then its prototype designed in this paper is produced in the lab, of which kinematics and dynamics simulations are carried out based on the rigid–flexible coupling virtual model. Simulation curves of the displacement and velocity of the mould are almost consistent with the ideal ones, which verifies the model built in this paper is rational. Furthermore, natural frequencies and mode shapes of the mechanism are calculated by dynamics simulation, and forces applied on leaf springs and revolute joints are analysed and effects of the basic parameters on these forces are also studied, which establish the basis for further studies and next application of this mechanism.     

INVESTIGATION INTO EFFECT OF SPRING PRESSURE ON PERFORMANCE OF BALANCED MECHANICAL SEALS

The loads acting on the sealing elements of balanced mechanical seals are analyzed. When the balance factor approaches the back pressure factor, the spring pressure will become main part of the face pressure. The leakage model of balanced mechanical seals is established on the base of M-B model for rough surface. Several GY-70 type balanced mechanical seals are tested. The influences of the spring pressure both on the leakage rate and on the friction characteristic of balanced mechanical seals are investigated. The research results indicate that as spring pressure increases, both the clear-ance between two end faces and the leakage rate will decrease, and the friction will be more serious because lubrication medium between the rotating ring and the stationary ring reduces, though the increase of the spring pressure may not be enough to change the face friction state of mechanical seals. There exists an optimum spring pressure for mechanical seal operation. Under this spring pres-sure, not only leakage rate is small, but also the seal end surfaces have a fine friction characteristic. Under different operating conditions, identical type mechanical seals may possess different spring pressure. Appropriate selection of spring pressure is valuable to realize long-period and small leakage rate operating of balanced mechanical seals.     

两纤WDM全光环网的保护和恢复与波长分配

研究了WDM环网的保护和恢复与波长分配问题，提出了一种改进的Greedy波长分配算法，仿真计算结果表明，该算法应用于WDM共享保护环(SPRING)获得了较高的波长利用率，同时本文比较了WDM环网的不同保护和恢复结构对波长资源配置的要求。     

新加坡产品认证制度概述

本文介绍了新加坡市场的产品认证制度,其中分别详细介绍了新加坡一般产品认证制度（消费者保护（安全要求）注册计划）和电信设备认证（IDA认证）。