abstract: Current exosuit technologies utilizing soft inflatable actuators for gait assistance have drawbacks of having slow dynamics and limited portability. The first part of this thesis focuses on addressing the aforementioned issues by using inflatable actuator composites (IAC) and a portable pneumatic source. Design, fabrication and finite element modeling of the IAC are presented. Volume optimization of the IAC is done by varying its internal volume using finite element methods. A portable air source for use in pneumatically actuated wearable devices is also presented. Evaluation of the system is carried out by analyzing its maximum pressure and flow output. Electro-pneumatic setup, design and fabrication of the developed air source are also shown. To provide assistance to the user using the exosuit in appropriate gait phases, a gait detection system is needed. In the second part of this thesis, a gait sensing system utilizing soft fabric based inflatable sensors embedded in a silicone based shoe insole is developed. Design, fabrication and mechanical characterization of the soft gait detection sensors are given. In addition, integration of the sensors, each capable of measuring loads of 700N in a silicone based shoe insole is also shown along with its possible application in detection of various gait phases. Finally, a possible integration of the actuators, air source and gait detection shoes in making of a portable soft exosuit for knee assistance is given. / Dissertation/Thesis / Masters Thesis Mechanical Engineering 2020

abstract: The term Poly-Limb stems from the rare birth defect syndrome, called Polymelia. Although Poly-Limbs in nature have often been nonfunctional, humans have had the fascination of functional Poly-Limbs. Science fiction has led us to believe that having Poly-Limbs leads to augmented manipulation abilities and higher work efficiency. To bring this to life however, requires a synergistic combination between robot manipulation and wearable robotics. Where traditional robots feature precision and speed in constrained environments, the emerging field of soft robotics feature robots that are inherently compliant, lightweight, and cost effective. These features highlight the applicability of soft robotic systems to design personal, collaborative, and wearable systems such as the Soft Poly-Limb. This dissertation presents the design and development of three actuator classes, made from various soft materials, such as elastomers and fabrics. These materials are initially studied and characterized, leading to actuators capable of various motion capabilities, like bending, twisting, extending, and contracting. These actuators are modeled and optimized, using computational models, in order to achieve the desired articulation and payload capabilities. Using these soft actuators, modular integrated designs are created for functional tasks that require larger degrees of freedom. This work focuses on the development, modeling, and evaluation of these soft robot prototypes. In the first steps to understand whether humans have the capability of collaborating with a wearable Soft Poly-Limb, multiple versions of the Soft Poly-Limb are developed for assisting daily living tasks. The system is evaluated not only for performance, but also for safety, customizability, and modularity. Efforts were also made to monitor the position and orientation of the Soft Poly-Limbs components through embedded soft sensors and first steps were taken in developing self-powered compo-nents to bring the system out into the world. This work has pushed the boundaries of developing high powered-to-weight soft manipulators that can interact side-by-side with a human user and builds the foundation upon which researchers can investigate whether the brain can support additional limbs and whether these systems can truly allow users to augment their manipulation capabilities to improve their daily lives. / Dissertation/Thesis / Doctoral Dissertation Systems Engineering 2020

Research into cultural dynamics and trend mechanisms has been used to “deconstruct” theinfluence structure of fashion in a way that can be applied to a hypothetical design strategy.The design strategy revolves around designing products with the intension to indirectlycommunicate an idea or ideas and by taking advantage of a products emotional value, toincrease structural and cognitive embeddedness of underlying ideas.The application of the strategy is the design of a smart product called “Gelo”. Gelo is a ‘smartwall’ concept that uses soft robotic actuators to transform its surface to adapt to changinglight conditions, improve room acoustics, and produce dynamic visual displays.By using HASEL soft robot actuators for movement, emerging technology could be exploredthrough the medium a conceptual consumer product while also allowing interestingfunctionality to be implemented to the Gelo concept. The addition of this functionalityallowed for ‘display like’ properties which are used to explore the idea of smart home devicesas a way of provide an enhanced emotional experienced.

Aging in humans is often associated with reduced muscle strength and difficulty in elevating the arm and sustaining it at a certain position. The aim of this master thesis is to propose a number of technical solutions integrated into a complete electronic system which can be used to support the user's muscle capacity and partially resist gravitational load. An electronic system consisting of sensors, a control unit and an actuator has been developed. The system is able to detect the user's motion intention based on an angle detection algorithm and perform kinematic control over the user's arm by adjusting the level of support at different degrees of elevation. A force control algorithm has been developed for controlling the actuating mechanism, providing the user with a natural and intuitive support during arm elevation. The implemented system is a first step towards the development of a medical assistive device for the elderly or patients with reduced muscle strength allowing them to independently perform a number of personal activities of daily life where active participation of the upper limb is required.

No description available.

Of the 795,000 people that suffer a stroke in the United States every year, 65% experience hemiparesis. Foot drop is a common gait pathology in people with lower-limb paresis and is often caused by neuropathy of the peroneal nerve that innervates the muscles responsible for ankle dorsiflexion. Foot drop can impede toe clearance and increase the risk of falling, the leading cause of injury among adults ≥65 years. Lower-limb robotic exoskeletons have been used for gait training and can aid with walking, but current devices on the market can be heavy, expensive, and constrained to in-clinic use. Soft wearable robotic devices offer a lightweight and cost-effective alternative to traditional lower-limb exoskeletons. In particular, soft pneumatic systems have the potential to provide a high power-to-weight ratio making them ideal for a wearable application. The soft pneumatic exosuit consists of a footplate to collect air, storage to temporarily house the collected air, and two pneumatic actuators to provide an assistive torque around the wearer’s ankle joint while walking. EMG and IMU sensors were integrated to control the opening and closing of solenoid valves so that assistive torques could be applied to the ankle joint at optimal moments during the gait cycle. Preliminary validation of the soft pneumatic exosuit on a healthy participant demonstrated that the system could successfully deliver the air required to contract the actuators when the EMG sensors detected an increase in muscle activity. These results demonstrate that the current soft pneumatic exosuit appears to be a promising alternative to current rehabilitation exoskeletons on the market while remaining portable and low-cost. / 2025-05-24T00:00:00Z

This thesis developed a novel theory of fiber jamming and experimentally verified it. The theory relates the performance, which is the ratio between the stiff and soft states of a fiber jamming chamber, to three relative design parameters: the ratio of the wall thickness to the membrane inner diameter, the ratio of the fiber diameter to membrane inner diameter, and the number of fibers. These three parameters, when held constant across different chamber sizes, hold the performance constant. To test the theory, three different types of fiber jamming chambers were built in three different sizes. Each chamber was set up as a cantilever beam and deflected 10mm in both the un-jammed (soft) and jammed (stiff) states. When the three design parameters were held constant, the performance of the chamber was consistent within 10\%. In contrast, when the parameters were altered, there was a statistically significant $p < .0001$ and noticeable effect on chamber performance. These two results can be used in tandem to design miniaturized fiber jamming chambers. These results also have a direct application in soft robots designed for minimally invasive surgery.

Soft actuation methods are a developing field of robotics deemed suitable for physical human-robot interactions due to the adaptability of materials and compliant structures. Thermo-active soft actuators are a subset of these which convert thermal energy to mechanical work in the form of elongation, bending, or twisting to conform to the environment. This study is divided into three major studies that all use actuators with a working principle of phase-change fluid vaporizing for expansion with applied heat from a Peltier. The first study evaluates the bandwidth and efficiency between (i) traditional Joule heating, and (ii) Peltier heating, finding that Peltier heating can considerably improve the operational bandwidth of the actuator. The second study uses a thin membrane actuator placed in a braided mesh to form a McKibben muscle capable of lifting 5N, and formed into a gripper capable of manipulating objects within the environment. The third study uses actuators of a solid, hollow and flexible Peltier embedded silicone structure and are evaluated and optimized in order to increase actuation speed, finding that the embedded flexible Peltier design was able to elongate over 50% of its original height in 20 seconds. The overall aim of all of these studies was to improve bandwidth, efficiency, actuator lifetime, and create more symmetrical actuation and deactuation cycles.

Editorial on the Research Topic. Novel Actuators, Sensors and Control Systems for Endoscopic Robots.

Mechanical metamaterials are becoming an emerging frontier in scientific research and engineering innovation due to its unique properties, arising from innovative geometrical designs rather than constituent materials. Reconfigurable metamaterials can change their shapes and structures dramatically under external forces or environmental stimuli. It offers an enhanced flexibility in performance by coupling dynamically changing structural configuration and tunable properties, which has found broad potential applications in 3D meso-structures assembly and programmable machines. Despite extensive studies on harnessing origami, the ancient paper folding art, for design of mechanical metamaterials, the study on utilizing its close cousin, kirigami (“kiri” means cut), for programmable reconfigurable mechanical metamaterials and machines remains largely unexplored. In this dissertation, I explore harnessing the uniqueness of cuts in kirigami for achieving extraordinary mechanical properties and multifunctionalities in krigami-based metamaterials, as well as its potential applications in programmable machines and soft robotics. I first exploit the design of hierarchical cuts for achieving high strength, high stretchability, and tunable mechanical properties in hierarchical rotation-based kirigami mechanical metamaterials. Hierarchical line cuts are introduced to a thin sheet composed of non-stretchable materials (copy paper), less stretchable materials (acrylics), and highly stretchable materials (silicone rubber, PDMS), to explore the role of constituent material properties. The cut unit in the shape of solid rectangles with the square shape as a special case was demonstrated for achieving the extreme stretchability via rigid rotation of cut units. It shows that a higher hierarchical level contributes to a higher expandability and lower stiffness to constituent material. However, when such kirigami structure is applied onto less-stretchable materials (e.g. acrylics), its stretchability is almost eliminated regardless of the hierarchical level, because severe stress concentration at rotation hinges leads to the structure failure at the very beginning stage of pattern transformation. To address this challenge, I propose a hinge design which can significantly reduce the stress concentration at cut tips and enable high stretchability for rotation-based kirigmai structure, even on acrylic thin sheet. I also study the tunable photonic behavior of proposed hierarchical kirigami metamaterial by simple strain-induced structural reconfiguration. I then explore the programmability of kiri-kirgami structures by introducing notches to the simplest kirigami structure patterned with parallel line cuts for breaking its deformation symmetry. Engraving the flat-cut kirigami structure enables programmable control of its out-of-plane tilting orientation, thus generating a variety of inhomogeneous structural configurations on demand. I find that compared to the its counterpart without engraving notches, the introduced notches have a negligible effect on both the stress-strain curve over the large strain range and the extreme stretchability, however, they reduce the critical buckling force largely. Furthermore, I demonstrate the adaptive kiri-kirigami structure through local actuation with its tilting directions to be programmed and switched in response to the change of environmental temperature. Lastly, I demonstrate the potential promising outcome of kiri-kirigami structures as adaptive building envelope in energy efficient buildings, especially in electric saving for lighting and cooling load saving through numerical simulation. In addition to kirigami based soft metamaterials, I also investigate the utilization of soft materials and soft structures for robotics functions. First, I explore the design of soft doming actuator upon pneumatic actuation and its implications in design of multifunctional soft machines. I propose a novel bilayer actuator, which is composed of patterned embedded pneumatic channel on top for radial expansion and a solid elastomeric layer on bottom for strain-limiting. I show that both the cavity volume and bending angle at the rim of the actuated dome can be controlled by tuning the height gradient of the pneumatic channel along the radial direction. I demonstrate its potential multifunctional applications in swimming, adhesion, and gripping. I further explore harnessing doming-based bilayer doming actuator for developing soft climbing robot. I characterize and optimize the maximum shear adhesion force of the proposed soft adhesion actuator for strong and rapid reversible adhesion on multiple types of smooth and semi-smooth surfaces. Based on the switchable adhesion actuator, I design and fabricate a novel load-carrying amphibious climbing soft robot (ACSR) by combining with a soft bending actuator. I demonstrate that it can operate on a wide range of foreign horizontal and vertical surfaces, including dry, wet, slippery, smooth, and semi-smooth ones on ground, as well as under water with certain load-carrying capability. I show that the vertical climbing speed can reach about 286 mm/min (1.6 body length/min) while carrying over 200g object (over 5 times the weight of ACSR itself) during climbing on ground and under water. / Mechanical Engineering