GE Tube Polishing System

The goal of this project is to automate the polishing process of brazed or welded areas on a tube assembly supplied by GE Aviation. An end-of-arm-tooling for a Fanuc 200iB was designed and fabricated to manipulate the tube. A work cell layout was determined and part fixtures were developed. A force controlled polishing system was implemented and interfaced with the Fanuc 200iB. Analytical and experimental analyses were conducted to determine the necessary polishing forces. Design considerations were made for future enhancements to the automated tube polishing system

Energy-based approach to develop soft robots

Soft robotic systems offer advantages against rigid robot systems in applications that involve physical robot-human interactions, unstructured or extreme environments, and manipulating delicate objects. Soft robots can offer inherently safe operation and adapt to unknown geometry of the environment or object. The current soft robot development approach is an empirical approach starting from a type of soft actuation technology, whereas the development of rigid robots can start from a top-level task in a System Engineering framework. The rigid robot developer can select from well-defined components to construct the task-orientated system. Soft robots are relatively novel systems compared with rigid robots and do not have well-defined components due to a wide range of soft actuation technologies. The initial choice of soft actuation technology places constraints on the system to perform the task. Soft robotic systems are not widely used despite the advantages compared to rigid robots. In this thesis, I study an abstraction approach to enable a System Engineering framework to develop soft robotic systems. My research focus is on an energy-based approach that encompasses the multi-domain nature of soft robotic systems. The impact on the final system from the energy transfer characteristics of the initial choice of the soft actuator has not been fully explored in the literature. I study how energy, and rate of energy transfer (power), can describe different components of each type of soft actuation and how the total energy can model the top-level system. This thesis includes (i) a literature review of soft robots; (ii) an abstraction approach based on bond-graph theory applied to soft actuation technologies; (iii) a port-Hamiltonian theory to describe the top-level soft robotic system, and (iv) an experimental application of the approach on a type of soft actuation technology. In summary, I explore how energy and rate of energy transfer can provide the abstraction approach and in time provide the well-defined components necessary for task-orientated design approaches in a System Engineering framework. In particular, I applied the approach to soft pneumatic systems for additional insights relevant to the development of future task-orientated soft robotic systems.EPSRC Doctoral Training Centre in Robotics and Autonomous Systems funding

Dynamic Morphological Computation Through Damping Design of Soft Continuum Robots

Inspired by nature, soft robotics aims at enhancing robots capabilities through the use of soft materials. This article presents the study of soft continuum robots which can change their dynamic behavior thanks to a proper design of their damping properties. It enables an under-actuated dynamic strategy to control multi-chamber pneumatic systems using a reduced number of feeding lines. The present work starts from the conceptual investigation of a way to tune the damping properties of soft continuum robots, and leverages on the introduction of viscous fluid within the soft chamber wall to produce dissipative actions. Several solutions are analyzed in simulations and the most promising one is tested experimentally. The proposed approach employs a layer of granular material immersed in viscous silicone oil to increase the damping effect. After validation and experimental characterization, the method is employed to build soft continuum actuators with different deformation patterns, i.e., extending, contracting and bending. Experimental results show the dynamic behavior of the presented actuators. Finally, the work reports information on how the actuators are designed and builded, together with a discussion about possible applications and uses

Scalability study for robotic hand platform

The goal of this thesis project was to determine the lower limit of scale for the RIT robotic grasping hand. This was accomplished using a combination of computer simulation and experimental studies. A force analysis was conducted to determine the size of air muscles required to achieve appropriate contact forces at a smaller scale. Input variables, such as the actuation force and tendon return force, were determined experimentally. A dynamic computer model of the hand system was then created using Recurdyn. This was used to predict the contact (grasping) force of the fingers at full-scale, half-scale, and quarter-scale. Correlation between the computer model and physical testing was achieved for both a life-size and half-scale finger assembly. To further demonstrate the scalability of the hand design, both half and quarter-scale robotic hand rapid prototype assemblies were built using 3D printing techniques. This thesis work identified the point where further miniaturization would require a change in the manufacturing process to micro-fabrication. Several techniques were compared as potential methods for making a production intent quarter-scale robotic hand. Investment casting, Swiss machining, and Selective Laser Sintering were the manufacturing techniques considered. A quarter-scale robotic hand tested the limits of each technology. Below this scale, micro-machining would be required. The break point for the current actuation method, air muscles, was also explored. Below the quarter-scale, an alternative actuation method would also be required. Electroactive Polymers were discussed as an option for the micro-scale. In summary, a dynamic model of the RIT robotic grasping hand was created and validated as scalable at full and half-scales. The model was then used to predict finger contact forces at the quarter-scale. The quarter-scale was identified as the break point in terms of the current RIT robotic grasping hand based on both manufacturing and actuation. A novel, prototype quarter-scale robotic hand assembly was successfully built by an additive manufacturing process, a high resolution 3D printer. However, further miniaturization would require alternate manufacturing techniques and actuation mechanisms

MUSME 2011 4 th International Symposium on Multibody Systems and Mechatronics

El libro de actas recoge las aportaciones de los autores a través de los correspondientes artículos a la Dinámica de Sistemas Multicuerpo y la Mecatrónica (Musme). Estas disciplinas se han convertido en una importante herramienta para diseñar máquinas, analizar prototipos virtuales y realizar análisis CAD sobre complejos sistemas mecánicos articulados multicuerpo. La dinámica de sistemas multicuerpo comprende un gran número de aspectos que incluyen la mecánica, dinámica estructural, matemáticas aplicadas, métodos de control, ciencia de los ordenadores y mecatrónica. Los artículos recogidos en el libro de actas están relacionados con alguno de los siguientes tópicos del congreso: Análisis y síntesis de mecanismos ; Diseño de algoritmos para sistemas mecatrónicos ; Procedimientos de simulación y resultados ; Prototipos y rendimiento ; Robots y micromáquinas ; Validaciones experimentales ; Teoría de simulación mecatrónica ; Sistemas mecatrónicos ; Control de sistemas mecatrónicosUniversitat Politècnica de València (2011). MUSME 2011 4 th International Symposium on Multibody Systems and Mechatronics. Editorial Universitat Politècnica de València. http://hdl.handle.net/10251/13224Archivo delegad

Bio-Mimetic Smart System Functioning Like Natural Skin and Muscle

Soft machines, or soft robotics, are emerging technologies bringing many exciting prospects for the coming future. Creating soft machines with biomimetic functions is of key importance for applications in bettering human life and creating more complex robotic systems. Various mechanisms have been adopted to mimic natural tactile sense, tough, muscular motion, and even artificial intelligence. Among these, developing a bio-mimetic system capable of self-healing and degradation that behaves like a muscular hydrostat is appealing for soft robotics. This thesis will mainly focus on developing both artificial skin and artificial muscles that can self-heal, be recycled, and function like biological tissue. To develop a biomimetic artificial skin, we adopted an imine-bonded polymer as the main component, and embedded silver nanoparticles as well as liquid metals to create conductive components. Our artificial skin is capable of re-healing and recycling, and can be mounted to a complex 3D surface without introducing damage and strains. Such artificial skin, at the same time, can sense pressure and temperature change, flow across the surface, and humidity change in the atmosphere. Recyclability enables this platform to not only serve as an artificial skin, but also for other electronics applications. The artificial muscles were also developed for this project based on a recently invented Liquid Crystal Elastomer, whose behavior is most similar to that of natural muscles. To achieve large actuation strains, a fast response, and small scale local controlling, a Liquid Metal was introduced for stimulating the artificial muscle. Over 100% linear contracting strain was realized based on such a combination, which is greater than that of natural muscles. Bending and twisting deformation were also realized easily on such system. To further demonstrate the advantages of our artificial muscle, we integrated it into other passive soft elastomers like Ecoflex to mimic the camouflage behavior of cephalopods

Compliant polymeric actuators as robot drive units

A co-polymer made from Polyvinyl Alcohol and Polyacrylic Acid (PVA-PAA) has been synthesized to form new robotic actuation systems which use the contractile and variable compliance properties of this material. The stimulation of these fibres is studied (particularly chemical activation using acetone and water), as are the factors which influence the response, especially those relating to its performance as an artificial muscle.Mathematical models and simulations of the dynamics of the polymeric strips have been developed, permitting a thorough analysis of the performance determining parameters. Using these models a control strategy has been designed and implemented, with experimental results being obtained for a gripper powered by a flexor/extensor pair formed using these polymeric actuators.An investigation of a second property of the polymer, its variable compliance is also included. Use of this feature has lead to the design, construction and testing of a multi degree-of-freedom dextrous hand, which despite having only a single actuator, can exercise independent control over each joint

Soft hand exoskeleton actuated with SMA fibres

The current project is based on developing a wearable and comfortable soft hand exoskeleton actuated with Shape Memory Alloy (SMA) fibres. The main purpose of this device is both, to be involved in rehabilitation exercises and assistive therapies for patients suffering from hands’ damage. This innovative idea presents an affordable and convenient alternative in the exoskeletons’ field, combining a light and non-expensive actuation along with biocompatible materials specifically tailored to patient’s hand anatomy. To generate the perfectly fitting glove, plastic moulds were 3D-printed after sketching them with Creo Parametric software. Then, silicone was poured into the casts and it cured maintaining the desired shape. Taking advantage of Joule’s effect, the current which flows though the SMA wires is capable of increasing temperature, causing a microstructure change and thus inducing contraction. This motion can be accurately controlled by a MATLAB-Simulink interface, achieving both flexion and extension so as to perform pincer grip. Furthermore, a force sensor embedded on silicone finger’s tip is used as a force feedback to evaluate the pressure applied by the subject when holding distinct objects.Ingeniería Biomédica (Plan 2010