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There is an increasing number of people with traumatic injury related to hand amputations. The amputees experience many problems, especially dealing with activities of daily living (ADLs). Hence, the prosthetic hand is designed to help amputees to perform daily activities. Customized prosthetic hand with high performance is very costly and use heavy DC motors for actuation. This paper presents a low-cost...
Intelligent perception to determine the physical interaction between robotic hands and the environment is a topic of great interest for the sensing and robotics communities. Sensor information on object stiffness and associated object deformation is essential to plan and execute stable and tight grasps. This paper proposes a novel robot-finger-integrated perception sensor to estimate the physical...
This paper presented a new design for underactuated robotic hand which has four grasping modes for objects. The robotic hand has three fingers. The underactuated mechanism of thumb is composed of gear-rack structure and the other two fingers work as a 2DOF gripper. The robotic hand can form both opening and closing motions with one motor. There is another motor which can control the distance between...
This paper provides a detailed analytic evaluation of the force-current relationship for a real underactuated gripper, whose geometry presents some differences with respect to the cases usually considered in the literature. Differently from other approaches, the model proposed can work in two ways: calculating the current needed to exert a given force, and calculating the force applied by the gripper...
In the case that tactile sensor matrices are placed at the fingers of a robotic gripper, it is possible to identify objects during grasping. This feature may be useful e.g. for sorting workpieces. In this article we present an approach for object identification using tactile information. For verification a test scenario is developed where the robot should sort workpieces which are based on Lego bricks...
A fundamental aspect of many human-robot collaborative tasks is object exchange or handover. Several techniques have been proposed to decide when a robot hand or gripper should release an object for a human to receive. However, these techniques typically neglect the reliability of the handover, assuming the process will occur without issue. Based on the fact that humans apply pulling forces in specific...
Gecko-inspired adhesive pads have a wide range of application with their characteristics of low preload, strong adhesion and easy detachment. However, the appearance of adhesive force needs adhesive pads with a micro-scale displacement to engage. Therefore, the microstroke table must be designed. In order to have a better adaptability for several surface structures, it is necessary to optimize the...
The problem of dexterous robotic manipulation of rigid objects by means of a cooperative robotic system is addressed in this paper. It is assumed that the robots can only push the object (unilateral constraints). In order to solve the aforementioned control problem, a centralized control algorithm with bounded torque inputs based on the Orthogonalization Principle and second order sliding mode control...
This paper proposes the use of an instrumented object for the study of the human grasping strategies. The proposed object is able to measure the grasping forces by means of three Force Sensitive Resistor (FSR) sensors and triaxial acceleration through an accelerometer. The object orientation angles (roll and pitch) can be estimated from the accelerometer output in quasi-static condition, whereas slippage...
In this paper, a solution for pruning tree branches close to electric power lines using a hexarotor helicopter equipped with a circular saw and a robotic gripper is proposed. The solution consists of flying to the target, in this case the branch to be pruned, fix the helicopter to it and finally, prune the tree branch with a circular saw. In this first approach, we propose a novel skew-gripper design...
For the rehabilitation and assistance of the hand functions, wearable devices have been developed, and the interest in tendon driven mechanisms have especially increased since it allows light weight and compact design. The tendon driven hand rehabilitation devices provides grasping force via exo-tendons routed on the dorsal and palmar sides of the hand pulled by remotely located actuators. However,...
In this paper, we address two of the most important challenges in development and control of assistive hand orthosis. First, supported by experimental results, we present a method to determine an optimal set of grasping poses, essential for grasping daily objects. Second, we present a method for determining the minimal number of surface EMG sensors and their locations to carry out EMG-based intention...
In this paper, the authors to demonstrate a novel and simple method to enable two finger grasping with one force sensor. 6-DOF haptic interface and a force sensor were used to implement this technique. The haptic device controls the position and orientation of two haptic avatars inside the virtual environment (VE), while the user can control the distance between the avatars by applying force on the...
It is known that a pseudo force sensation of pulling in one direction is generated by presenting an asymmetrical vibration stimulus with different accelerations in a round trip. The present study employed a similar phenomenon using the asymmetric rotational vibration of a direct-current motor to present the pseudo force sensation to multiple fingertips. We investigated the frequency characteristics...
Stroke survivors who experience severe hemipare-sis often cannot completely recover the use of their hand and arm. Many of the rehabilitation devices currently available are designed to increase the functional recovery right after the stroke when, in some cases, biological restoring and plastic reorganization of the central nervous system can take place. However, this is not always the case. Even...
This paper solves the problem of computing the best grasp in a discrete point set based on a popular grasp quality measure, namely the largest origin-centered ball contained in the grasp wrench set. So far, the solution to this problem is very limited. Noticing that the quality measure for a grasp is equal to the minimum value of the support function of its grasp wrench set over all directions and...
In spite of the remarkable benefits that minimally invasive surgery provides for patients, the absence of force feedback is still a significant disadvantage. Several studies have been performed to address this issue; however, an accurate sterilizable force sensing technology for measuring axial and grasping forces is still missing. In this work, an innovative partial grasper has been designed and...
Grasping an object in the presence of unpredictable disturbances and with no previous knowledge of the geometry and mass distribution of it represents a significant challenge in Robotics. Also, grasping an object with sufficient force to prevent slippage, whilst not damaging or deforming the shape of the object proves to be still an intricate challenge despite the existence of a huge body of literature...
This study presents a soft robotic gripper for grasping irregular objects. The optimal design is based on the proposed topology optimization and size optimization methods with the objective to maximize the mechanical advantage (MA, which is defined as the ratio of output force to the input force) of the analyzed compliant mechanism. The optimal design is prototyped using silicon rubber material. Experimental...
This paper discusses robust capture of a free-floating target using a robotic arm. The position error resulting from sensor errors and time delay can cause undesired contact and unstable control. In this paper, we propose a caging-based rigid gripper and impedance control, which enables the robot to capture the target robustly without precise motion tracking and large force interaction. The performance...
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