165 research outputs found

    Manipulating liquids with robots: A sloshing-free solution

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    This paper addresses the problem of suppressing sloshing dynamics in liquid handling robotic systems by an appropriate design of position/orientation trajectories. Specifically, a dynamic system, i.e. the exponential filter, is used to filter the desired trajectory for the liquid-filled vessel moved by the robot and counteract the sloshing effect. To this aim, the vessel has been modelled as a spherical pendulum of proper mass/length subject to the accelerations imposed by the robot and the problem has been approached in terms of vibration suppression to cancel the residual oscillations of the pendulum, i.e. the pendulum swing at the end of the reference rest-to-rest motion. In addition, in order to reduce the relative motion between liquid and vessel, an orientation compensation mechanism has been devised aiming to maintain the vessel aligned with the pendulum during the motion. The effectiveness of the proposed approach, both in simple point-to-point motions and complex multi-point trajectories, has been proved by means of an exhaustive set of experimental tests on an industrial manipulator that moves a cylindrical vessel filled with water. This innovative solution effectively uses all the degrees of freedom of the robotic manipulator to successfully suppress sloshing, thus significantly improving the performances of the robotic system. Furthermore, the proposed solution, showing a high degree of robustness as well as intrinsic design simplicity, is very promising for designing novel industrial robotics applications with a short time-to-market across key manufacturing sectors (e.g., food and beverage, among others)

    Dynamics and Control of Higher-order Nonholonomic Systems

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    A theoretical framework is established for the control of higher-order nonholonomic systems, defined as systems that satisfy higher-order nonintegrable constraints. A model for such systems is developed in terms of differential-algebraic equations defined on a higher-order tangent bundle. A number of control-theoretic properties such as nonintegrability, controllability, and stabilizability are presented. Higher-order nonholonomic systems are shown to be strongly accessible and, under certain conditions, small time locally controllable at any equilibrium. There are important examples of higher-order nonholonomic systems that are asymptotically stabilizable via smooth feedback, including space vehicles with multiple slosh modes and Prismatic-Prismatic-Revolute (PPR) robots moving open liquid containers, as well as an interesting class of systems that do not admit asymptotically stabilizing continuous static or dynamic state feedback. Specific assumptions are introduced to define this class, which includes important examples of robotic systems. A discontinuous nonlinear feedback control algorithm is developed to steer any initial state to the equilibrium at the origin. The applicability of the theoretical development is illustrated through two examples: control of a planar PPR robot manipulator subject to a jerk constraint and control of a point mass moving on a constant torsion curve in a three dimensional space

    Zbornik sažetaka

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    NASA Tech Briefs, September 1990

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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 Sciences; Life Sciences

    Contemporary Robotics

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    This book book is a collection of 18 chapters written by internationally recognized experts and well-known professionals of the field. Chapters contribute to diverse facets of contemporary robotics and autonomous systems. The volume is organized in four thematic parts according to the main subjects, regarding the recent advances in the contemporary robotics. The first thematic topics of the book are devoted to the theoretical issues. This includes development of algorithms for automatic trajectory generation using redudancy resolution scheme, intelligent algorithms for robotic grasping, modelling approach for reactive mode handling of flexible manufacturing and design of an advanced controller for robot manipulators. The second part of the book deals with different aspects of robot calibration and sensing. This includes a geometric and treshold calibration of a multiple robotic line-vision system, robot-based inline 2D/3D quality monitoring using picture-giving and laser triangulation, and a study on prospective polymer composite materials for flexible tactile sensors. The third part addresses issues of mobile robots and multi-agent systems, including SLAM of mobile robots based on fusion of odometry and visual data, configuration of a localization system by a team of mobile robots, development of generic real-time motion controller for differential mobile robots, control of fuel cells of mobile robots, modelling of omni-directional wheeled-based robots, building of hunter- hybrid tracking environment, as well as design of a cooperative control in distributed population-based multi-agent approach. The fourth part presents recent approaches and results in humanoid and bioinspirative robotics. It deals with design of adaptive control of anthropomorphic biped gait, building of dynamic-based simulation for humanoid robot walking, building controller for perceptual motor control dynamics of humans and biomimetic approach to control mechatronic structure using smart materials

    Advances in Mechanical Systems Dynamics 2020

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    The fundamentals of mechanical system dynamics were established before the beginning of the industrial era. The 18th century was a very important time for science and was characterized by the development of classical mechanics. This development progressed in the 19th century, and new, important applications related to industrialization were found and studied. The development of computers in the 20th century revolutionized mechanical system dynamics owing to the development of numerical simulation. We are now in the presence of the fourth industrial revolution. Mechanical systems are increasingly integrated with electrical, fluidic, and electronic systems, and the industrial environment has become characterized by the cyber-physical systems of industry 4.0. Within this framework, the status-of-the-art has become represented by integrated mechanical systems and supported by accurate dynamic models able to predict their dynamic behavior. Therefore, mechanical systems dynamics will play a central role in forthcoming years. This Special Issue aims to disseminate the latest research findings and ideas in the field of mechanical systems dynamics, with particular emphasis on novel trends and applications

    Zbornik sažetaka

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    HydroDog: A Quadruped Robot Actuated by Soft, Fluidic Muscles

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    This report presents the very first effort aimed to develop a legged terrestrial robot actuated by Hydro Muscles, which are elastic tubes actuated by fluid, constrained by fabric that extend and contract emulating life-like performance of biological muscles. The team designed and manufactured a 30-pound quadruped “dog” using versatile aluminum extrusions and minimally machined components. The team tested and observed a variety of bounding gaits that resulted from different skeletal/muscular geometries and actuation times. These tests yielded varying jump heights and robot forward velocities. Future projects should extensively research optimal leg kinematics to maximize the mechanical power the muscles apply on the robot

    HydroDog: A Quadruped Robot Actuated by Soft Fluidic Muscles

    Get PDF
    This report presents the very first effort aimed to develop a legged terrestrial robot actuated by Hydro Muscles, which are elastic tubes actuated by fluid, constrained by fabric that extend and contract emulating life-like performance of biological muscles. The team designed and manufactured a 30-pound quadruped “dog” using versatile aluminum extrusions and minimally machined components. The team tested and observed a variety of bounding gaits that resulted from different skeletal/muscular geometries and actuation times. These tests yielded varying jump heights and robot forward velocities. Future projects should extensively research optimal leg kinematics to maximize the mechanical power the muscles apply on the robot

    HydroDog: A Quadruped Robot Actuated by Soft Fluidic Muscles

    Get PDF
    This report presents the very first effort aimed to develop a legged terrestrial robot actuated by Hydro Muscles, which are elastic tubes actuated by fluid, constrained by fabric that extend and contract emulating life-like performance of biological muscles. The team designed and manufactured a 30-pound quadruped “dog” using versatile aluminum extrusions and minimally machined components. The team tested and observed a variety of bounding gaits that resulted from different skeletal/muscular geometries and actuation times. These tests yielded varying jump heights and robot forward velocities. Future projects should extensively research optimal leg kinematics to maximize the mechanical power the muscles apply on the robot
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