The Cluster of Excellence ‘Centre for Tactile Internet with Human-in-the-Loop (CeTI)’1 addresses developments and inventions for the use in or as smart devices in many areas, such as Industry 4.0, medicine and skill learning. The application of sensor units in smart textiles is widespread and used in various industry branches. Besides sensors, the development of textile actuating units is a relevant research topic. This paper discusses a theoretical actuator concept that leads to a ready-to-implement fiber-based electrostatic brake concept (passive actuator). Generally, the set-up is similar to a capacitor. Two different variants are presented according to the design of the dielectric and outer electrode layer. The dielectric material, its thickness, manufacturing process, future properties and implementation possibilities of the concepts are considered. Finally, a proof of concept with first results is presented.

Learning complex skills like ball juggling is usually challenging since the balls fall fast in reality. The maturity and rapid development of extended reality (XR) technologies have created opportunities to practice in a virtual environment. The challenge, however, is to connect the virtual world with the real world coherently. We develop a holistic solution with two main components: an XR environment with virtual balls whose falling speed can be adjusted and a haptic glove to provide the sense of catching the ball. By slowing down the falling speed of the balls, the learners can learn individual skills of throwing balls, catching them, and practicing juggling.

Mixed reality is becoming an integral element of increasing educational and work processes. To create maximum nativeness of the process, users in most cases use their own hands as the main element of controlling the virtual environment. Modern software solutions can detect hands quite accurately and can see and accurately reflect changes in the position of hands, but cannot understand the purpose for which concrete movement of hands in space is performed. In this study, we considered the issue of understanding user movements to create a realistic educational simulator of juggling in mixed reality. We proposed a solution to determine the behavioral cause of the user’s hands to improve the accuracy of the simulator.

Functional electrical stimulation (FES) aims to improve the gait pattern in cases of weak foot dorsiflexion (foot lifter weakness) and, therefore, increase the liveability of people suffering from chronic diseases of the central nervous system, e.g., multiple sclerosis. One important component of FES is the detection of the knee angle in order to enable the situational triggering of dorsiflexion in the right gait phase by electrical impulses. This paper presents an alternative approach to sensors for motion capture in the form of weft-knitted strain sensors. The use of textile-based strain sensors instead of conventional strain gauges offers the major advantage of direct integration during the knitting process and therefore a very discreet integration into garments. This in turn contributes to the fact that the FES system can be implemented in the form of functional leggings that are suitable for inconspicuous daily use without disturbing the wearer unnecessarily. Different designs of the weft-knitted strain sensor and the influence on its measurement behavior were investigated. The designs differed in terms of the integration direction of the sensor (wale- or course-wise) and the width of the sensor (number of loops) in a weft-knitted textile structure.

The paper presents the fabrication and characterization of low-cost, highly sensitive fabric-based sensors. Novel Kirigami patterns were formed on conductive fabrics using a laser patterning process. Conductive fabrics have been essential in forming efficient strain sensors due to their high mechanical flexibility, biocompatible nature, and tolerance to washability. They have been used to create flexible prototypes measuring gross and fine motor skills. Silitex (R) is one of the conductive fabrics that has been very new in the sensing sector, and not much work has been done yet. The developed sensors are a proof-of-concept with a Kirigami pattern. The design, development, and characterization of these prototypes have been presented here. The results have provided a base for deploying these sensors for fully-functionalized strain sensing systems.

Functional electrical stimulation (FES) aims to improve the gait pattern in case of foot drop of people suffering chronic diseases, e.g., multiple sclerosis. The fibular nerve can be stimulated by electrical impulses sent through electrodes on the skin, which leads to the contraction of the corresponding muscles. One major disadvantage of commercial FES devices is their bulky design. The paper presents an alternative approach of weft-knitted strain sensors that are directly integrated into the knee area of a functional legging suitable for daily use. To initiate electrical impulses for FES at the right time, the textile strain sensors are used as soft triggers.

In this letter, we present a smart glove for Tactile Internet applications. The individual finger motions are measured via resistive strain sensors. The strain sensors are directly integrated with the textile glove and are produced in an automated process. The sensor glove is integrated with sensor conditioning, controller, wireless frontend, and battery. We investigate the measured sensor data for a variety of gestures, demonstrating the good quality of the data allowing for easy and low-energy gesture recognition.

For signal transmission and sensing in stretchable structures for human motion monitoring or proprioception of soft robots, textiles with electronically conductive yarns are a promising option. Many recent publications employ silver-plated yarns in knits, braids, wovens for strain or pressure sensing purposes as well as heating fabrics or twisted string actuators. Silver-plated yarns are available in a wide range of base materials, yarn counts and twists. These structural properties significantly influence the electrical and electromechanical behavior of such yarns. However, until now little research has been carried out on the yarns themselves. To close this research gap, several variations of a single yarn type are electromechanically characterized. Additionally, tensile tests with synchronous resistance measurements are performed. From these measurements, sensor metrics are derived and calculated to compare the different variants quantitatively.

Communicating science to the public is increasingly important. Demonstrators are a valuable and established tool for communication in technology research and development. However, their role in communicating current science and technology to the public has not received much attention neither in research nor practice. This paper reflects on the design and usage of the demonstrator “Rock, Paper, Scissors”, which we developed to communicate current advances in Human-Robot Interaction to public audiences. We discuss two years of “Rock, Paper, Scissors” in action and its evolution within this period. We conclude with an outlook to future work regarding technology development and evaluation of science communication.

A growing interest in interdisciplinary research can be observed throughout the past decades. Previous work has provided general principles for facilitating collaborative work in academia, but direct interdisciplinary experiences are quite rare in the literature. In this article, we provide our insights on executing interdisciplinary research in a university context. First, we outline how the university structure and the variety of disciplines involved in the research team shaped our interdisciplinary work. Then, we discuss our direct experience with a key step-stone in conducting interdisciplinary research: forge shared common goals. Lastly, we discuss how the involved research disciplines bene?ted from the interdisciplinary discussions and projects, describing some of the outcomes achieved. Throughout the article, we elaborate the lessons we have learned along the way. This paper has implications for researchers and institutions approaching interdisciplinary endeavours. It can hopefully help them navigate through the challenges of interdisciplinary collaboration.

The Cluster of Excellence “Centre for Tactile Internet with Human-in-the-Loop (CeTI)” deals with developments and inventions concerning smart devices used in many fields, e.g. industry 4.0, medicine and skill learning. These kind of applications require smart devices, sensors, actors and conductive structures. Textile structures address these applications by meeting requirements such of being flexible, adaptable and wearable. Within this paper, the development of a protective coating for electrically conductive (EC) yarns is captured. These EC yarns are nowadays often used for smart textile applications. One challenge in their application is the integration into textile structures. Often, the handling and use of EC yarns lead on the one hand to damages on the surface of the yarn and on the other hand to reduced electromechanically characteristics. This paper aims to characterize these EC yarns in regard to develop a suitable protective coating based on polypropylene (PP). To achieve this development, an extensive characterization of the EC yarns as well as the protective coating itself is important. The surface free energy (SFE), the topographical and the chemical characteristics are necessary for developing a suitable protective coating. However, the yarns are characterized before and after implementation into the textile structure and furthermore after the coating respectively with the developed finish.

Natural muscles, that convert chemical energy derived from glucose into mechanical and thermal energy, are capable of performing complex movements. This natural muscle power was the only way to perform mechanical work in a targeted manner for millions of years. In the course of thousands of years of technical development, mankind has succeeded in harnessing various physical and chemical phenomena to drive specific mechanical processes. Wind and water power, steam and combustion engines or electric motors are just a few examples. However, in order to make the diversity and flexibility of natural motion patterns usable for machines, attempts have been made for many years to develop artificial muscles. These man-made smart materials or structures are able to react to environmental conditions by significantly changing their shape or size. For the design of effective artificial muscles that closely resemble the natural original, the usage of textile technology offers great advantages. By means of weaving, individual actuators can be parallelized, which enables the transmission of greater forces. By knitting the maximum stretching performance can be enhanced by combining the intrinsic stretching capacity of the actuators with the structural-geometric stretching capacity of the fabric. Furthermore textile production techniques are well suited for the requirement-specific, individual placement of actuators in order to achieve the optimal geometry for the respective needs in every load case. Ongoing technical development has created fiber based and non-fibrous artificial muscles that are capable of mimicking and even out-performing their biological prodigy. Meanwhile, a large number of partly similar, but also very different functional principles and configurations were developed, each with its own specific characteristics. This paper provides an overview of the relevant and most promising technical approaches for realizing artificial muscles, classifies them to specific material types and explains the mechanisms used as well as the possible textile applications.

The internet of things is a key driver for new developments in the fields of medicine, industry 4.0 and gaming. Consequently, the interaction of virtual and real world by smart interconnecting of devices in our everyday life is the basis idea of the Cluster of Excellence "Centre for Tactile Internet with Human-in-the-Loop" (CeTI) at TU Dresden. To enable a user-centric approach in CeTI innovative textile structures, mainly knitted smart gloves, and their functionalization by integration of sensors and sensory yarns are focus of research activities.

The Internet of Skills aims at investigating how Tactile Internet with Human-in-the-Loop (TaHiL) technology can contribute to offer skill sets and expert capabilities to anybody, even at the most remote and diverse geographical regions. It will provide immersive training to laypersons (children, adults, and seniors) with or without physical or cognitive limitations to promote the learning of skills. This chapter provides an overview of the main issues that need to be addressed when humans and cyber-physical system interactions are designed and tools are developed to promote skill learning. The state of the art and the challenges to be tackled with regard to learning, technical, and design issues are presented. In collaboration with the target primary research field of humans presented in Chapter 9, the key technology challenge of intelligent networks presented in Chapter 6 and of haptic learning presented in Chapter 8, the latest technology innovations and knowledge will be implemented in developing skill learning programs that can be adapted to address factors, needs, and goals of specific individuals.

Carbon particle-filled polymers are frequently used as stretchable conductors and strain sensors. Many of the proposed resistance-based stretchable strain sensors show non-monotonic strain response, especially under dynamic conditions. This is commonly attributed to the competing destruction and reformation of the conductive network, but the underlying mechanism is still unknown. Therefore, systematic cyclic tensile tests are performed with carbon black-filled silicone yarns, which show that the non-monotonic behavior found depends on strain rate, strain history, and maximum applied strain. Based on the experimental results, a novel model is developed that incorporates the visco-elastic nature of the polymer and representations of the percolative networks in strain direction as well as the transversal direction. It is shown that the non-monotonic behavior is a result of the combination of visco-elasticity and transversal contraction of the percolative network. The model is an equivalent circuit model and its simulation results are in good agreement with the experimental results. The model can be used to further understand the strain sensing behavior of conductive polymers and optimize sensor systems.

The internet of things (IOT) and industry 4.0 are main drivers for new developments. Consequently the interaction of virtual and real world by smart interconnecting of devices in our everyday life is the basis idea of the Cluster of Excellence "Centre for Tactile Internet with Human-in-the-Loop" (CeTI) at TU Dresden. To enable a user-centric approach in CeTI innovative textile structures, mainly knitted fabrics, and their functionalization by integration of sensors and sensor yarns are under investigation. In the first phase suitable sensor yarns and innovative structures are developed and characterized as a reference for later investigations.

Textile membranes are suitable for a wide range of applications due to their user-adjustable properties, which can be modified based on both the textile reinforcement structure and the coating material. Complex dynamic loads are involved in typical usage scenarios for load-bearing components of textile architecture, e.g., unsupported convertible roofs of halls or stadiums, temporary buildings, large-volume consumable media storage and the main sail of sailing boats. It is generally known that particularly in the area of membrane joints, successive degradation of seam strength may occur. This paper addresses the realization of an in situ measurement system for textile surface formation in textile membranes, which is introduced locally in the area of the joining zone and is compatible with the materials as well as the ultrasonic welding process itself. These development efforts are supported by a numerical investigation in terms of the serviceability and residual load-carrying capacity of the joining zone and the textile membrane surface area.