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Assistive robotic arms are increasingly enabling users with upper extremity disabilities to perform activities of daily living on their own. However, the increased capability and dexterity of the arms also makes them harder to control with simple, low-dimensional interfaces like joy-sticks and sip-and-puff interfaces. A common technique to control a high-dimensional system like an arm with a low-dimensional...
This paper presents a heuristic solution for the inverse kinematics problem. The heuristic consists on combining the distance between the actual position and the desired position of the gripper with the direction of the best manipulability of the robot. Theoretical results are validated by digital simulations resolute.
This paper aims to exploit technology in saving lives; a robotic arm is designed for EOD (Explosive Ordnance Disposal) applications that can rival the EOD robotic arms available in the market, in terms of both its capabilities and functionality, and still cost a small fraction of their price. Though there are many robotic arms that are commercially available, which can be used to handle different...
In this work, the open-source plugin OpenMRH is presented for the Open Robotics Automation Virtual Environment (OpenRAVE), a simulation environment for testing, developing and deploying motion planning algorithms. The proposed plugin allows for a fast and automated generation of different modular hand models. OpenMRH combines virtual-prototyping and modular concepts. Each modular model is generated...
In the present paper, we deal with the grasping aspect regarding reactive object retrieving during fast aerial pick-and-place maneuevers. The paper addresses the problem of the optimal grabbing of an object by means of a 5 degrees of freedom (DoF) gripper. Also, is introduced the optimization framework for the identification of the optimal contact points between the end-effector and the object. In...
This paper describes a geometrical method for grasping objects wherein an object is caged by rigid parts of a robot hand and simultaneously grasped by soft parts attached to said rigid parts. We term this process as caging-based grasping. In this study, we derive concrete conditions for two- and three-dimensional caging-based grasping of objects of various shapes using circular robots and multi-fingered...
This thesis presents a biomechatronics approach to the design and fabrication of an artificial robotic arm called Artificial Hand Gripper (AHG), consisting of a shoulder, arm, elbow, forearm, wrist and hand. Detail 3D designs of the AHG are described including an elbow powered by a car's power window motor, DC motor powered wrist and a string actuated AHG with 5 artificial fingers which acts as slave...
This paper describes a vacuum gripper that imitates the sucker of the octopus which is useful for the handling of industrial parts. It is difficult to use other sucker type vacuum grippers, but this gripper can adhere to rigid materials since the sucker is flexible. In the present work, we evaluated the effect of a liquid membrane on vacuum suction, since the industrial part often has a liquid membrane...
In this paper, we propose a novel robot hand called uGRIPP (Underactuated Gripper for Power and Precision Grasp) which has underactuated fingers for dual-arm manipulation tasks. A newly designed underactuated linkage enables the robot hand to achieve not only an adaptive grasp and a pinch grasp, but also manipulation by a palm of the hand. We introduce performance of the proposed linkage by a static...
In this study, we experimentally investigated the process leading to fracture in tofu grasping by deformable fingertips filled with a fluid. In our previous papers [1, 2], we developed deformable fingertips using a rubber bag filled with a viscoelastic fluid, and presented a strategy for delicate tofu grasping without any advance knowledge about fracture. However, the predication point was close to...
This paper explores the manipulation of a grasped object by pushing it against its environment. Relying on precise arm motions and detailed models of frictional contact, prehensile pushing enables dexterous manipulation with simple manipulators, such as those currently available in industrial settings, and those likely affordable by service and field robots.
In clinics, customized archwires are demanded for lingual orthodontic treatment. However, only very experienced orthodontists can handle the manual appliance preparation. This pattern not only occupies lots of the orthodontist's labor time, but also can not ensure the accuracy of the appliances. Therefore, a robotic system was developed for automatic and accurate orthodontic archwire bending in our...
This paper introduces and characterizes the Baxter Easyhand, a new 3D printed hand derived from the Yale T42 hand [5], [10], but designed specifically to be mounted on the Baxter robot from Rethink robotics. Because this hand is designed specifically for Baxter, we are able to make some important simplifications in the design relative to other 3D printed hands. In particular, the Easyhand is smaller...
A novel variable stiffness actuator composed of a dielectric elastomer actuator (DEA) and a low-melting-point-alloy (LMPA) embedded silicone substrate is demonstrated. The device which we call variable stiffness dielectric elastomer actuator (VSDEA) enables functional soft robots with a simplified structure, where the DEA generates a bending actuation and the LMPA provides controllable stiffness between...
Controlling a robotic gripper to handle objects in different sizes and shapes in real-time is a complex task. The challenge is to adapt and position the gripper according to a target object. In this work, by considering a three fingered robotic gripper with a finger structure similar to that of human finger, we study the positioning of fingers in a gripper in the two dimensional plane. Using an inverse...
The design, modeling and control of a 5 degrees-of-freedom light-weight robot manipulator is presented in this paper. The proposed robot arm, named Prisma Ultra-Lightweight 5 ARm (PUL5AR), is employed to execute manipulation tasks equipped on board of a vertical take-off and landing unmanned aerial vehicle. The arm is compact and light-weight. Its mechanics is designed such that it can fold on itself...
Symbolic reasoners generate plans which are often not exploiting the robot capabilities and are sensitive to runtime disturbances. This work proposes a scheduler as an interface between a discrete, symbolic plan and a motion control based on constraint optimization. Acting as a local reasoner, the scheduler valuates a set of predicates to decide when an action will be executed. Given a task specification...
Recent work [1], [2], [3] has shown promising results in learning from demonstrations for the manipulation of deformable objects. Their approach finds a non-rigid registration between points in the demonstration scene and points in the test scene. This registration is then extrapolated and applied to the gripper motions in the demonstration scene to obtain the gripper motions for the test scene. If...
In this paper, we show that the free configuration space of a Kirchhoff elastic rod is path-connected. By free configuration space, we mean the set of all equilibrium configurations of the rod that are stable (i.e. locally minimize elastic potential energy) and do not experience self-intersections. We also provide semi-analytical expressions for paths in the free configuration space that connect any...
Reliable precision grasping is a pre-condition for manipulation tasks e.g. in assembly and packaging tasks. Especially for small and light objects robust grasping is extremely challenging since even slight errors in the object pose or dimensions lead to irreparable failures caused by unintended finger-object contacts. State of the art techniques address the problem of grasping in the presence of uncertainty...
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