Flexible gripping technology for the automated handling of limp technical textiles in composites industry

A high level of cost-intensive manual tasks in the manufacturing process of composite parts impedes a further propagation of those innovative structures in important German industrial branches like the automotive sector or aviation. Especially the handling of semi-finished goods in several key process-chains could not be automated efficiently so far due to a great variety of materials and part contours as well as difficult handling properties of the limp, textile parts. Hence within the presented work a highly-flexible gripper system based on low-vacuum-suction is introduced, which is the result of a methodical investigation in the ideal gripping principle. Special actuators and an intelligent control strategy are combined into a selective gripping technology, which allows an automatic adaption of the pressure based holding force to different contours and materials, by closing certain apertures of a perforated plate. The experimental validation of a realized robotic end-effector shows that the challenging requirements of modern composite production could be fulfilled as the structural integrity of the technical textiles is preserved during the handling processes.     

卡盘的若干设计计算问题

以“夹持系数”取代传统的摩擦系数；对卡盘的主要零件重新进行了受力分析，推导出能满足各零件设计计算之用的计算公式；并提出了提高卡盘夹持能力的有效措施：（１）减小卡瓦和卡圈斜面之间的摩擦系数；（２）提高卡瓦和主动钻杆之间的夹持系数     

机器人气动夹持力的CNN-LSTM建模估计方法

由于气动系统具有迟滞、强非线性特性，难以直接依据气压信号实现气动夹持力的有效控制，因此采用建模估计夹持力是实现无力传感器低成本控制的有效途径。为此，提出一种基于卷积神经网络(CNN)优化的长短期记忆神经网络(LSTM)低成本气动夹持力估计方法。根据工业机器人末端气爪夹持力与气路历史输入/输出有关的特点，采用了具有记忆特性的LSTM网络建立无传感器气压/压力估计模型;针对直接采用LSTM网络进行建模存在误差大的问题，利用CNN提取输入信息中气压和夹持力的非线性关系，进一步对LSTM网络结构进行优化，提高模型描述气压和夹持力之间多值对应特性与非线性迟滞特性的能力，实现气爪的夹持力有效估计。实验结果表明：相比LSTM预测模型，所提模型的建模估计与验证估计均方根误差分别减少77.14%和70.83%，最大误差分别减少79.80%和78.84%,证明了所提建模估计方法的有效性。     

Gripping by controllable wet adhesion using a magnetorheological fluid

The magnetorheological properties of ferrofluids (or smart, or active fluids) are well known, and are currently exploited in shear in advanced damping systems in the automotive industry, robotics (prosthesis), and machine tools (chatter reduction, positioning). This paper proposes an end effector for gripping by a novel form of controllable wet adhesion inspired by gastropod pedal mucus. The design of a gripper has been proposed, along with performance analysis based on experiments on various parameters, materials and surfaces, exhibiting robustness in unknown and dirty environment, typical of disassembly. Benefits over competing handling technologies and future research directions in this new area have been addressed.     

提高气体喷射器效率的有效方法

在大量实验和计算的基础上,探讨出冶金工程用喷射器喷口位置对喷射器效率的影响规律,提出在喷射器结构一定的情况下,改变喷口在吸入管的位置,可以使喷射器效率提高30%以上.     

Intelligent gripper technology for the handling of carbon fiber material

Nowadays, the serial production of Carbon Fiber-Reinforced Polymers remains a challenge for the industry. Their production and application have been limited by the intensive manual work required to produce them and the resulting elevated manufacturing costs. Moreover, the production handling tasks are fulfilled to a limited extent by the gripping systems currently available in the market. The delicate process and specific material requirements of these polymers compromise the feasibility and use of automated gripper systems. An innovative solution for the automated material handling of carbon fiber textiles developed by the wbk Institute for Production Science in cooperation with J. Schmalz GmbH will be presented in this paper. The main focus of this study deals with measuring principles to increase energy efficiency, process reliability and adaptability of a gripping system using low pressure grippers. This study presents suitable solutions for the implementation of low pressure grippers in a production environment.     

Constitutive model for the elastic–plastic analysis of porous sintered materials

It is a known fact that it is very difficult to implement the algorithm of plasticity of porous materials in FEM commercial programs for different types and characteristics. The aim of this paper is to put forward a flexible model of plasticity of porous materials by implementing it into the general purpose finite element program ABAQUS®. A modified algorithm is developed in this paper which takes into account the effect of an isotropic work hardening of the porous material. This is incorporated into the FEM program to yield a flexible solution for different yielding criterion. The present criterion is compared with other known published work and was found to be in good agreement. It was found that all the failure criteria used were successfully implemented using the newly developed algorithm. Also, the present criterion is adequately adjusted to fit all other results obtained from other criteria of failure. Finally, some of these published criteria had not been implemented previously for use in the FEM programs, but in this paper were made to do so. Other theoretical results will also be presented.     

基于协作机器人的物流分拣软体夹具设计

为解决传统夹具适应性较弱的问题,设计一种以热塑性聚氨酯弹性体为材料的软体夹具。该材料低温柔顺性好、强度高,因此软体夹具可以与物体表面实现良好的贴合。利用SolidWorks完成软体夹具的方案设计,并在ABAQUS中进行夹爪适应性分析,计算夹爪抓取不同物体所产生的变形和应力。通过弯曲角度测试和末端接触力测试选择合适的夹爪长度,并通过3D打印制作软体夹具。在Baxter机器人上进行了质量测试和抓取试验,结果表明：该软体夹具可以有效、稳定、无损地抓取日常生活用品。     

Process design and modelling methods for automated handling and draping strategies for composite components

Fibre-reinforced-thermoplastics (FRT) have excellent weight-specific properties compared to conventional engineering materials. However, a wider dissemination of this technology into existing plant technologies is restrained by the low degree of automation. Complex FRT component geometries pose special challenges to gripper design and handling strategies in automated preform processes regarding limp material behaviour and fast cooling time. The preform quality is influenced by the component geometry, reinforcing fabric, and preform process. This paper presents the development of an automated handling and draping strategy, which is validated by finite-element-analysis and experimental testing to meet the requirements of large-scale preforming processes for complex geometries.     

Design and implementation of multiaxial force sensing gripper fingers

This paper focuses on the integration of elementary force sensors into the fingers of parallel grippers. The theory of the approach of integrating three sensor elements into a gripper finger is described and the results of the practical evaluations are given. Strain gauges are used as elementary sensor elements. Two different design approaches are evaluated. The first one uses H-shaped cut-outs to weaken the structure at designated areas. The measurement accuracy of this system is compared with a second approach without cut-outs, which is easier to manufacture. Finite element analysis is used in both approaches to simulate the behaviour and to determine the best locations for strain gauge application. The performances of both design concepts are experimentally evaluated. It can be seen that the results of the finite-element analysis are correct and that a satisfactory decoupling of the basic sensors can be achieved using a physical or mathematical approach. Both prototypes are able to measure the gripping force with sufficient accuracy.     

改善DF喷吸钻排屑性能的措施

分析了喷吸钻喷吸原理，提出了改善排屑性能的措施。     

动力卡盘的设计与计算

文章介绍了三爪动力卡盘的工作原理及其设计计算.通过力的平衡方程,得出夹紧力与推拉力的关系.讨论了夹紧力和极限转速是卡盘设计的理论基础.     

Research on gripping conditions in profile ring rolling of raceway groove

Ring gripping means that under the pressure of roll and friction, ring grips the rolling gap and produces rotating rolling motion, thus ring thickness receives equal rolling and the outer diameter expands equally, and this is a sufficient condition for ring rolling forming. In this paper, gripping course in profile ring rolling of raceway groove is analyzed based on ring rolling principle and static theory. The gripping mechanical model for profile ring rolling of raceway groove is established, and gripping conditions are researched according to the geometrical relationship in rolling. The results indicate that ring could be ensured to continuously grip the gap in rolling by controlling feed per revolution and preventing it from exceeding the maximum feed per revolution allowed by ring gripping. Furthermore, influencing factors of gripping conditions are analyzed. At last, the experiments and the FE simulation for profile ring rolling of raceway groove are performed to testify the validity of gripping conditions. Both the experimental and simulation results show that when feed satisfies gripping conditions, ring can continuously grip the gap and be formed by rolling. Otherwise, ring cannot grip the gap and is squashed between the rolls. The results of this research provide a theoretical basis for design of technological parameters of profile ring rolling of raceway groove.     

蒸汽喷射器内的激波效应对喷射性能的影响

利用Fluent软件对蒸汽喷射器内二维流场进行数值模拟计算,研究工作流体压力、背压、喷嘴位置对喷射性能的影响,并对喷射器流场内激波的产生、发展和结束进行了分析。结果表明,蒸汽喷射器工作流体压力、工作背压、喷嘴位置在特定的工况下都具有相对应的最优值。激波产生和结束的位置对喷射器性能影响很大:当第一激波由喷嘴出口产生并延伸到混合段出口附近时结束、第二激波在扩散室入口附近结束时,引射系数最大;当激波过早或过晚结束时,都会影响喷射器的性能。     

Rigid plastic constitutive theory for porous materials including void evolution and mixed hardening effects

A new rigid plastic constitutive model was constructed in the previous research for porous ductile materials based on modified Gurson’s yield function. However, in that model, attention was focused on the effect of isotropic hardening on plastic deformation and damage processes of porous materials. In this paper, that model is further extended to a more general model in which both the isotropic and the kinematic hardening mechanisms of porous materials are incorporated. The characteristics and self-consistency of the extended model are briefly discussed.     

可靠性计算在压铸模顶杆设计上的应用

应用刚度可靠性设计的理论 ,对顶杆的工作情况进行分析 ,提出了一种更加合理的顶杆直径计算公式 ,并将其用于实际生产     

可靠性计算在压铸模顶杆设计上的应用

应用刚度可靠性设计的理论 ,对顶杆的工作情况进行分析 ,提出了一种更加合理的顶杆直径计算公式 ,并将其用于实际生产     

The effect of strain hardening in the extrusion of bimetallic tubes of porous internal layer

The effect of strain-hardening features of porous materials treated by cold extrusion through a conical die is studied theoretically in the present paper. The theoretical model developed by using the fundamentals of the Plasticity Theory of Real Porous Materials investigates all technological parameters affected in the case of extruding bimetallic tubes with a porous internal layer. Comparative analysis between strain-hardened and ideally plastic materials used in the fabrication of bimetallic tubular components, as far as their effect on various technological extrusion parameters is concerned, such as variation of porosity, applied load, level of total deformation, etc., has been conducted successfully, providing, in this manner, with useful concluding remarks from engineering point of view.     

Studies of physico-chemical properties of modified carbon nanomaterials for sorption extraction of radionuclides. II. Sorption properties of charcoal formed in electron-beam processing of plant materials

This work studies the effect of the porous structure of carbon adsorbent samples obtained using the method of electron-beam processing (EBP) on their physico-chemical properties and sorption properties in respect to Tc(VII). A complex study of the porous structure of the chosen samples was performed. The possibility is shown of developing a thinner porous structure in these carbon materials including micro- and mesopores by means of regulation of radiation exposure combined with treatment by different reagents. It is found that treatment by modifying agents (urea, thiourea, potassium rhodanide) of sorbing materials obtained by radiation processing of the initial plant material enhances their sorption properties in respect to the Tc(VII) anions.     

多功能柔性机器人夹具的设计与应用

为了解决搬运码垛机器人利用率低和更换夹具比较麻烦等问题,设计了一种多功能柔性自动切换机器人夹具,包括机架、夹取装置、吸取装置和驱动装置等。该夹具同时具有吸取功能和夹取功能,并可通过机械臂驱动夹具做三维运动及旋转。结合机器视觉识别,可在工作范围内对工件采用不同的方式进行夹取,实现一台机器人同时服务2种不同类型工件或2条生产线,大大提高了机器人的利用率。该夹具已应用在壁挂炉生产线的搬运机器人上,使得搬运码垛工人的数量从10人降低到1人,工人的劳动强度大幅度降低,约18个月收回投入成本,效果很好。