Two Tendon-Driven Systems Using Pneumatic Balloons

In recent years, Japanese society has been aging, creating a shortage of young workers. Robots are expected to be useful to perform tasks such as rehabilitation therapy, nursing elderly people and day-to-day work support for elderly people. In particular, robots that are designed for use in the fields of medical care and welfare must be safe for the human environment because they often come into contact with humans. Furthermore, robots must have dexterity that is similar to that of humans. Under these circumstances, tendon-driven systems of two types using flexible silicone rubber materials have been developed. They are lightweight and have characteristics resembling those of human muscle. This paper describes the basic features and mechanisms of two tendon-driven systems that we have developed as a soft actuator. Furthermore, basic properties of the system are evaluated and compared with those of human muscles.     

Low temperature chemical synthesis of nanosized ceramic powders

Abstract

A variety of nanosized (particle dia. <100 nm) ceramic powders have been prepared from metal ion complex based precursor solutions. The precursor solution was prepared at room temperature from metal hydroxides, nitrates, or acetates mixed with suitable complexing agents such as amines, carboxylic acids, hydroxy carboxylic acids, or poly-hydroxy compounds. Calcination of the precursor mass at low external temperatures produces the nanosized ceramic powders. The examples discussed include perovskites, i.e. lead zirconate titanate PbZr_0·6 Ti_0·4O₃(PZT) and lead magnesium niobate PbMg_1/3 Nb_2/3 O₃ (PMN).     

Effect of layer compliance on frictional behavior of soft robotic fingers

In this paper, the modeling and design for frictional loads applied by robotic fingertips through a soft contact interface are investigated. The dependence of the sustainable friction forces and moments due to the normal force applied on the contact area is studied. A model that considers the dependence of both the contact area and the coefficient of friction on the application of normal force is proposed. Specimens of simplified fingertips, made with different materials and shaped with different thickness of the covering soft layer, were tested in order to validate the proposed model via designed experiments. The results obtained have very important relevance to the design of robotic hands and fingers equipped with soft pads or skins, and can help in the choice of suitable features for the different layers of contact pads or skins.     

Microbial Corrosion Hazard in Fuel Storage Tanks in the Presence of Corrosion Inhibitors

Abstract

Tests were carried out in five light fuel oil storage tanks placed outdoors in the vicinity of Stockholm, Sweden, to study the effectiveness of some commercially available corrosion inhibitors in the presence of certain micro-organisms. Corrosion in the aqueous phase caused by Desulphovibrio desulphuricans, Thiobacillus ferro-oxidans and Cladosporium resinae was effectively stopped by the addition of a sodium nitrite-sodium tetraborate mixture, but was enhanced by each of three commercial oil-soluble inhibitors. In some cases the corrosion rate exceeded 3 mm/year. The results are of a preliminary nature, but give cause for alarm and suggest the need for further investigation.     

Soft mechanochemical synthesis of MgFe2O4 nanoparticles from the mixture of α-Fe2O3 with Mg(OH)2 and Fe(OH)3 with Mg(OH)2

Abstract

The influence of long term soft milling of a mixture of (1) Mg(OH)₂ and α-Fe₂O₃ and (2) Mg(OH)₂ and Fe(OH)₃ powders in a planetary ball mill on the reaction synthesis of nanosized MgFe₂O₄ ferrites was studied. Soft mechanochemical reaction leading to formation of the MgFe₂O₄ spinel phase was followed by scanning electron microscopy, transmission electron microscopy, X-ray diffraction and magnetisation measurements. The spinel phase formation was first observed after 5 h of milling and its formation was completed after 15 h in case (2). The synthesised MgFe₂O₄ ferrite had a nanocrystalline structure with a crystallite size of about 10 and 15 nm respectively for cases (1) and (2). Measurements after 15 h of milling show magnetisation values of 15·23 and 10·14 J T^–1 kg^–1 respectively for cases (1) and (2).     

Miniature Pneumatic Curling Rubber Actuator Generating Bidirectional Motion with One Air-Supply Tube

Soft actuators driven by pneumatic pressure are promising actuators for mechanical systems in medical, biological, agriculture, welfare fields and so on, because they can ensure high safety for fragile objects from their low mechanical impedance. In this study, a new rubber pneumatic actuator made from silicone rubber was developed. Composed of one chamber and one air-supply tube, it can generate curling motion in two directions by using positive and negative pneumatic pressure. The rubber actuator, for generating bidirectional motion, was designed to achieve an efficient shape by nonlinear finite element method analysis, and was fabricated by a molding and rubber bonding process using excimer light. The fabricated actuator was able to generate curling motion in two directions successfully. The displacement and force characteristics of the actuator were measured by using a motion capture system and a load cell. As an example application of the actuator, a robotic soft hand with three actuators was constructed and its effectiveness was confirmed by experiments.     

A soft-tissue gelatin bioadhesive reinforced with a proteinoid

A soft-tissue bioadhesive was prepared with gelatin reinforced with proteinoids containing high proportions of carboxyl groups and amine groups. Proteinoids are synthetic copolymers of naturally occurring amino acids. Proteinoids were mixed with gelatin, the base material, and glutaraldehyde, a cross-linking agent, was added to form an imide linkage. The bond strength of the gelatin–thermal protein–glutaraldehyde (GTPG) adhesive was measured by applying the adhesive between the dermal sides of two excised rat skin sheets. An enhanced bond strength of the adhesive was observed in proteinoid formulations. The adhesive characteristics of gelatin reinforced with a proteinoid showed a higher bond strength than those of commercial sealants.     

Integrated Design of an Ionic Polymer–Metal Composite Actuator/Sensor

We are studying the robotic application of ionic polymer–metal composite (IPMC). The characteristics of IPMC greatly depend on the type of counterions, and it is considered that the performance of the actuators can be improved by combining the actuators with several types of counterions and applying an integrated control. IPMC also has a sensor function, as the IPMC film generates an electromotive force when it is deformed. It has the possibility to be integrated into an IPMC actuator with soft actuation. In this paper, we consider an integrated design of an IPMC actuator/sensor, and investigate control of the combined IPMC actuators using H _∞ control and the construction of an IPMC sensor system.     

Inclusion engineering: a keytool in achieving steelmaking operations stability at OneSteel Whyalla

Abstract

A new billet casting machine and ladle metallurgy furnace were commissioned at OneSteel (formerly BHP) Whyalla steelworks in June and October of 1999. The production of low Mn/Si ratio grades using, at first, an oxygen reheating station, and then later a ladle metallurgy furnace, provided many challenges to the achievement of stable steelmaking and casting operations. The multiphase equilibrium model as developed by the Commonwealth Scientific Industrial Research Organisation (CSIRO) has been used to solve complex metallurgical problems of practical importance in the production of silicon killed steels. Subtle changes to ladle practice for dissolved oxygen content combined with calcium treatment dictates inclusion composition and liquidus. Inclusion composition control has been a key requirement for making open cast product with good surface quality, and also for the control of refractory stopper erosion for submerged cast grades.     

利用SIP协议扩展实现SIP-NAT网关

参考SIP-NAT草案思想,利用对SIP(会话初始化协议)的两个扩展,修改传统NAT模块,在网络层识别SIP消息,对SIP消息进行解析处理,从而实现私网用户与公网用户之间进行会话.