122 research outputs found

    3D printing assisted development of bioinspired structure and device for advanced engineering

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    Smart materials with bio-inspired structure and stimuli responsive features can sense the external and internal condition changes, such as temperature, light intensity, pH or ion concentration. Those unique functions have been widely utilized in cutting edge engineering applications, such as flexible sensors, soft robotics and tissue engineering. Meanwhile, conventional manufacturing methods such as moulding, and lithography-based microfabrication still represent the mainstream force in scale up manufacturing. Considerable limitations for these technologies, such as on demand rapid prototyping, the high cost and low-volume production, remain to be overcome. In this PhD project, I explored the advanced manufacturing in facilitating the complex structure, with higher controllability, lower prototyping cost and extended applications (flexible sensors, soft robots, biomedical devices, etc.). The key practice is to utilize the high resolution 3D printing technology to create dedicated bio inspired structures based on functional materials. Combined with advanced micro/nano engineering, we have achieved a variety of techniques/prototypes for future applications, such as optical control, micro-fluidic and bio-medical systems, etc

    Mechatronic Systems

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    Mechatronics, the synergistic blend of mechanics, electronics, and computer science, has evolved over the past twenty five years, leading to a novel stage of engineering design. By integrating the best design practices with the most advanced technologies, mechatronics aims at realizing high-quality products, guaranteeing at the same time a substantial reduction of time and costs of manufacturing. Mechatronic systems are manifold and range from machine components, motion generators, and power producing machines to more complex devices, such as robotic systems and transportation vehicles. With its twenty chapters, which collect contributions from many researchers worldwide, this book provides an excellent survey of recent work in the field of mechatronics with applications in various fields, like robotics, medical and assistive technology, human-machine interaction, unmanned vehicles, manufacturing, and education. We would like to thank all the authors who have invested a great deal of time to write such interesting chapters, which we are sure will be valuable to the readers. Chapters 1 to 6 deal with applications of mechatronics for the development of robotic systems. Medical and assistive technologies and human-machine interaction systems are the topic of chapters 7 to 13.Chapters 14 and 15 concern mechatronic systems for autonomous vehicles. Chapters 16-19 deal with mechatronics in manufacturing contexts. Chapter 20 concludes the book, describing a method for the installation of mechatronics education in schools

    Space Exploration Robotic Systems - Orbital Manipulation Mechanisms

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    In the future, orbital space robots will assist humans in space by constructing and maintaining space modules and structures. Robotic manipulators will play essential roles in orbital operations. This work is devoted to the implemented designs of two different orbital manipulation mechanical grippers developed in collaboration with Thales Alenia Space Italy and NASA Jet Propulsion Laboratory – California Institute of Technology. The consensus to a study phase for an IXV (Intermediate eXperimental Vehicle) successor, a preoperational vehicle called SPACE RIDER (Space Rider Reusable Integrated Demonstrator for European Return), has been recently enlarged, as approved during last EU Ministerial Council. One of the main project task consists in developing SPACE RIDER to conduct on orbit servicing activity with no docking. SPACE RIDER would be provided with a robotic manipulator system (arm and gripper) able to transfer cargos, such as scientific payloads, from low Earth orbiting platforms to SPACE RIDER cargo bay. The platform is a part of a space tug designed to move small satellites and other payloads from Low Earth Orbit (LEO) to Geosynchronous Equatorial Orbit (GEO) and viceversa. The assumed housing cargo bay requirements in terms of volume (<100l) and mass (<50kg) combined with the required overall arm dimensions (4m length), and mass of the cargo (5-30kg) force to developing an innovative robotic manipulator with the task-oriented end effector. It results in a seven degree-of-freedom arm to ensure a high degree of dexterity and a dedicate end-effector designed to grasp the cargo interface. The gripper concept developed consists in a multi-finger hand able to lock both translational and rotational cargo degrees of freedom through an innovative underactuation strategy to limit its mass and volume. A configuration study on the cargo handle interface was performed together with some computer aided design models and multibody analysis of the whole system to prove its feasibility. Finally, the concept of system control architecture, the test report and the gripper structural analysis were defined. In order to be able to accurately analyze a sample of Martian soil and to determine if life was present on the red planet, a lot of mission concepts have been formulating to reach Mars and to bring back a terrain sample. NASA JPL has been studying such mission concepts for many years. This concept is made up of three intermediate mission accomplishments. Mars 2020 is the first mission envisioned to collect the terrain sample and to seal it in sample tubes. These sealed sample tubes could be inserted in a spherical envelope named Orbiting Sample (OS). A Mars Ascent Vehicle (MAV) is the notional rocket designed to bring this sample off Mars, and a Rendezvous Orbiting Capture System (ROCS) is the mission conceived to bring this sample back to Earth through the Earth Entry Vehicle (EEV). MOSTT is the technical work study to create new concepts able to capture and reorient an OS. This maneuver is particularly important because we do not know an OS incoming orientation and we need to be able to capture, to reorient it (2 rotational degrees of freedom), and to retain an OS (3 translational degrees of freedom and 2 rotational ones). Planetary protection requirements generate a need to enclose an OS in two shells and to seal it through a process called Break-The-Chain (BTC). Considering the EEV would return back to Earth, the tubes orientation and position have to be known in detail to prevent any possible damage during the Earth hard landing (acceleration of ∼1300g). Tests and analysis report that in order for the hermetic seals of the sample tubes to survive the impact, they should be located above an OS equator. Due to other system uncertainties an OS presents the potential requirement to be properly reoriented before being inserted inside the EEV. Planetary protection issues and landing safety are critical mission points and provide potential strict requirements to MOSTT system configuration. This task deals with the concept, design, and testbed realization of an innovative electro-mechanical system to reorient an OS consistent with all the necessary potential requirements. One of these electro-mechanical systems consists of a controlled-motorized wiper that explores all an OS surface until it engages with a pin on an OS surface and brings it to the final home location reorienting an OS. This mechanism is expected to be robust to the incoming OS orientation and to reorient it to the desired position using only one degree of freedom rotational actuator

    Functional Soft Robotic Actuators Based on Dielectric Elastomers

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    Dielectric elastomer actuators (DEAs) are a promising soft actuator technology for robotics. Adding robotic functionalities--folding, variable stiffness, and adhesion--into their actuator design is a novel method to create functionalized robots with simplified actuator configurations. We first propose a foldable actuator that has a simple antagonistic DEA configuration allowing bidirectional actuation and passive folding. To prove the concept, a foldable elevon actuator with outline size of 70 mm × 130 mm is developed with a performance specification matched to a 400 mm wingspan micro air vehicle (MAV) of mass 130 g. The developed actuator exhibits actuation angles up to ± 26 ° and a torque of 2720 mN·mm in good agreement with a prediction model. During a flight, two of these integrated elevon actuators well controlled the MAV, as proven by a strong correlation of 0.7 between the control signal and the MAV motion. We next propose a variable stiffness actuator consisting of a pre-stretched DEA bonded on a low-melting-point alloy (LMPA) embedded silicone substrate. The phase of the LMPA changes between liquid and solid enabling variable stiffness of the structure, between soft and rigid states, while the DEA generates a bending actuation. A proof-of-concept actuator with dimension 40 mm length × 10mm width × 1mm thickness and a mass of 1 g is fabricated and characterized. Actuation is observed up to 47.5 ° angle and yielding up to 2.4 mN of force in the soft state. The stiffness in the rigid state is ~90 × larger than an actuator without LMPA. We develop a two-finger gripper in which the actuators act as the fingers. The rigid state allows picking up an object mass of 11 g (108 mN), to be picked up even though the actuated grasping force is only 2.4 mN. We finally propose an electroadhesion actuator that has a DEA design simultaneously maximizing electroadhesion and electrostatic actuation, while allowing self-sensing by employing an interdigitated electrode geometry. The concept is validated through development of a two-finger soft gripper, and experimental samples are characterized to address an optimal design. We observe that the proposed DEA design generates 10 × larger electroadhesion force compared to a conventional DEA design, equating to a gripper with a high holding force (3.5 N shear force for 1 cm^2) yet a low grasping force (1 mN). These features make the developed simple gripper to handle a wide range of challenging objects such as highly-deformable water balloons (35.6 g), flat paper (0.8 g), and a raw chicken egg (60.9 g), with its lightweight (1.5 g) and fast movement (100 ms to close fingers). The results in this thesis address the creation of the functionalized robots and expanding the use of DEAs in robotics

    NASA Tech Briefs, February 1988

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    Topics covered include: New Product Ideas; NASA TU Services; Electronic Components and Circuits; Electronic Systems; Physical Sciences; Materials; Computer Programs; Mechanics; Machinery; Fabrication Technology; Mathematics and Information Systems; and Life Sciences

    Technology 2000, volume 1

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    The purpose of the conference was to increase awareness of existing NASA developed technologies that are available for immediate use in the development of new products and processes, and to lay the groundwork for the effective utilization of emerging technologies. There were sessions on the following: Computer technology and software engineering; Human factors engineering and life sciences; Information and data management; Material sciences; Manufacturing and fabrication technology; Power, energy, and control systems; Robotics; Sensors and measurement technology; Artificial intelligence; Environmental technology; Optics and communications; and Superconductivity

    Basil Leaf Automation

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    Recent population and wage increases have forced farmers to grow more food without a proportionate increase in work force. Automation is a key factor in reducing cost and increasing efficiency. In this paper, we explore our automation solution that utilizes position manipulation and vision processing to identify, pick up, and drop a leaf into a can. Two stepper motors and a linear actuator drove the three-dimensional actuation. Leaf and can recognition were accomplished through edge detection and machine learning algorithms. Testing proved subsystem-level functionality and proof of concept of a delicate autonomous pick-and-place robot
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