This paper presents TouchpadAnyWear, a novel family of textile-integrated force sensors capable of multi-modal touch input, encompassing micro-gesture detection, two-dimensional (2D) continuous input, and force-sensitive strokes. This thin (<1.5 mm) and conformal device features high spatial resolution sensing and motion artifact tolerance through its unique capacitive sensor architecture. The sensor consists of a knitted textile compressive core, sandwiched by stretchable silver electrodes, and conductive textile shielding layers on both sides. With a high-density sensor pixel array (25/cm2), TouchpadAnyWear can detect touch input locations and sizes with millimeter-scale spatial resolution and a wide range of force inputs (0.05 N to 20 N). The incorporation of miniature polymer domes, referred to as “poly-islands”, onto the knitted textile locally stiffens the sensing areas, thereby reducing motion artifacts during deformation. These poly-islands also provide passive tactile feedback to users, allowing for eyes-free localization of the active sensing pixels. Design choices and sensor performance are evaluated using in-depth mechanical characterization. Demonstrations include an 8-by-8 grid sensor as a miniature high-resolution touchpad and a T-shaped sensor for thumb-to-finger micro-gesture input. User evaluations validate the effectiveness and usability of TouchpadAnyWear in daily interaction contexts, such as tapping, forceful pressing, swiping, 2D cursor control, and 2D stroke-based gestures. This paper further discusses potential applications and explorations for TouchpadAnyWear in wearable smart devices, gaming, and augmented reality devices.

Incorporating compliance into shape-changing displays can improve their wearability and actuation modalities. While recent advances in soft actuators highlight promising paths for soft shape-changing displays, these displays currently face some practical challenges of device failure and limited actuator displacement. A monolithic fabrication processes means the device is challenging to repair, for a single point of failure often renders the whole device ineffective. We have leveraged a modular hyperelastic bubble array layer to create a soft shape-changing skin. The modularity of this device allows for rapid repair of individual bubbles and fast prototyping, and the spherical, hyperelastic actuators enable an increase in degrees of freedom due to bubble-to-bubble interactions. Furthermore, we present a forward kinematic description of our device, incorporating these bubble-to-bubble interactions and the nonlinear instabilities unique to hyperelastic actuator inflation. We demonstrate the utility of this soft shape-changing skin as a haptic display that can be worn comfortably or applied to passive interactive objects such as a computer mouse.

SleeveIO is a modular and reconfigurable hardware platform for rapid prototyping of multimodal wearable haptic feedback interactions. SleeveIO features engineered machine-knitted sleeve and band substrates, and five categories of haptic feedback actuator modules including vibrotactors, bellows, muscles, suction/puffing cups, and quad-chamber actuators. A universal magnetic attachment mechanism unifies the different types of actuators, enabling countless multimodal haptic experiences involving combinations of different actuator types in different configurations. SleeveIO is compatible with a variety of hardware/software control platforms, such as FlowIO [42], which enables individual control of each haptic actuator and makes the system battery-powered and untethered. This paper presents the SleeveIO platform in detail along with replication resources, a novel generalized approach to making different types of haptic actuators modular and interoperable, new application possibilities enabled by SleeveIO, and a pilot assessment of the viability of the platform as a whole and each module individually.

Recent advances in the rapidly growing field of soft robotics highlight the potential for innovations in wearable soft robotics to meet challenges and opportunities affecting individuals, society, and the economy. Some of the most promising application areas include wearable haptic interfaces, assistive robotics, and biomedical devices. Several attributes of soft robotic systems make them well-suited for use in human-wearable applications. Such systems can be designed to accommodate the complex morphology and movements of the human body, can afford sufficient compliance to ensure safe operation in intimate proximity with humans, and can provide context-appropriate haptic feedback or assistance to their wearers. Many soft robotic systems have been designed to resemble garments or wearables that are already widely used today. Such systems could one day become seamlessly integrated into a myriad of human activities and environments. Here, we review emerging advances in wearable soft robotic technologies and systems, including numerous examples from prior research. We discuss important considerations for the design of such systems based on functional concerns, wearability, and ergonomics. We describe an array of design strategies that have been adopted in prior research. We review wearable soft robotics applications in diverse domains, survey sensing and actuation technologies, materials, and fabrication methods. We conclude by discussing frontiers, challenges, and future prospects for soft, wearable robotics.

A key challenge in robotics is to create efficient methods for grasping objects with diverse shapes, sizes, poses, and properties. Grasping with hand-like end effectors often requires careful selection of hand orientation and finger placement. Here, we present a fingerless soft gripper capable of efficiently generating multiple grasping modes. It is based on a soft, cylindrical accordion structure containing coupled, parallel fluidic channels, which are controlled via pressure supplied from a single fluidic port. Inflation opens the gripper orifice for enveloping an object, while deflation allows it to produce grasping forces. The interior is patterned with a gecko-like skin that increases friction, enabling the gripper to lift objects weighing up to 20 N. Our design ensures that fragile objects, such as eggs, can be safely handled, by virtue of a wall buckling mechanism. In reverse, the gripper can be deflated to reach into an opening or orifice then inflated to grasp objects with handles or cavities. The gripper may also integrate a lip that enables it to form a seal and, upon inflating, to generate suction for lifting objects with flat surfaces. In this article, we describe the design and fabrication of this device and present an analytical model of its behavior when operated from a single fluidic port. In experiments, we demonstrate its ability to grasp diverse objects, and show that its performance is well described by our model. Our findings show how a fingerless soft gripper can efficiently perform a variety of grasping operations. Such devices could improve the ability of robotic systems to meet applications in areas of great economic and societal importance.

Integration of soft haptic devices into garments can improve their usability and wearability for daily computing interactions. In this paper, we introduce PneuSleeve, a fabric-based, compact, and highly expressive forearm sleeve which can render a broad range of haptic stimuli including compression, skin stretch, and vibration. The haptic stimuli are generated by controlling pneumatic pressure inside embroidered stretchable tubes. The actuation configuration includes two compression actuators on the proximal and distal forearm, and four uniformly distributed linear actuators around and tangent to the forearm. Further, to ensure a suitable grip force, two soft mutual capacitance sensors are fabricated and integrated into the compression actuators, and a closed-loop force controller is implemented. We physically characterize the static and dynamic behavior of the actuators, as well as the performance of closed-loop control. We quantitatively evaluate the psychophysical characteristics of the six actuators in a set of user studies. Finally, we show the expressiveness of PneuSleeve by evaluating combined haptic stimuli using subjective assessments.

This paper presents the design, development and preliminary evaluation of a soft-inflatable exosuit for knee rehabilitation. Soft-inflatable actuators made of heat-sealable thermoplastic polyurethane (TPU) materials are fabricated in two different beam-like structures (I and O cross-section actuators) and mechanically characterized for their torque performance in knee-extension assistance. The fabrication procedure of both types of actuators is presented as well as their integration into a lightweight, low-cost and body-conforming interface. To detect the activation duration of the device during the gait cycle, a soft-silicone insole with embedded force-sensitive resistors (FSRs) is used. In evaluation studies, the soft-inflatable exosuit device is tested for its ability to reduce muscle activity during the swing phase of the knee. Using sEMG (surface electromyography) sensors, the rectus femoris muscle group of a healthy individual is recorded while walking on a treadmill at a constant speed, with and without the soft device. Preliminary testing presents a promising 7% reduction in muscle activity and demonstrates the applicability of the soft-inflatable exosuit in knee rehabilitation scenarios.