Haptic systems have only recently started to be designed with wearability in mind. Compact, unobtrusive, inexpensive, easy-to-wear, and lightweight haptic devices enable researchers to provide compelling touch sensations to multiple parts of the body, significantly increasing the applicability of haptics in many fields, such as robotics, rehabilitation, gaming, and immersive systems. In this respect, wearable haptics has a great potential in the fields of virtual and augmented reality. Being able to touch virtual objects in a wearable and unobtrusive way may indeed open new exciting avenues for the fields of haptics and VR. This work presents a novel wearable haptic system for immersive virtual reality experiences. It conveys the sensation of touching objects made of different materials, rendering pressure and texture stimuli through a moving platform and a vibrotactile abbrv-doi-hyperref-narrowmotor. The device is composed of two platforms: one placed on the nail side of the finger and one in contact with the finger pad, connected by three cables. One small servomotor controls the length of the cables, moving the platform towards or away from the fingertip. One voice coil actuator, embedded in the platform, provides vibrotactile stimuli to the user.

Bilateral telemanipulation refers to frameworks in which a human operator manipulates a master robotic interface and a slave robotic device emulates the behavior of the master, while haptic feedback is provided to the operator. For multi-contact bilateral teleoperation wc intend master and slave systems that can establish multiple contact points with the user and with the environment. A paradigmatic example can be a multi-lingered robotic hand teleoperated by the human hand. Two of the most critical issues in this context are: (i) how to provide haptic feedback on multiple points of the human hand; (ii) how to solve the correspondence problem between the human hand and the robotic slave device. In this work, we propose finger-worn devices able to apply a three dimensional vector of force at a specific contact point to solve the multicontact feedback problem. For the correspondence problem, we propose an object-based mapping procedure. The approach is based on two virtual objects, defined both at the master and slave sides, to capture the human hand motion and to compute the related force feedback. The proposed approach has been tested in a telemanipulation framework where the master side was composed of a Leap Motion sensor used to track the hand plus three wearable haptic devices, while a robotic hand/arm system performed a manipulation task as slave.

In this paper a novel teleoperation framework for aerial robots that physically interact with the environment is presented. This framework allows to teleoperate the robot both in contact-free flight and in physical contact with the environment in order, e.g., to apply desired forces on objects of the environment. The framework is build upon an impedance-like indirect interaction force controller that allows to use standard underactuated aerial robots as force effectors. Haptic feedback from the master side enables the user to feel the contact forces exerted by the robot. An automatic potential field-based slowing-down policy is used by the robot to ensure a smooth transition between the contact-free motion phase and the force interaction phase. The effectiveness of the approach has been shown in extensive human-in-the-loop simulations including remote pressing of buttons on a surface and pushing a cart until it touches a wall.

In this paper we present a mathematical framework to describe the interaction between compliant hands and environmental constraints during grasping tasks. In the proposed model, we considered compliance at wrist, joint and contact level. We modeled the general case in which the hand is in contact with the object and the surrounding environment. All the other contact cases can be derived from the proposed system of equations. We performed several numerical simulation using the SynGrasp Matlab Toolbox to prove the consistency of the proposed model. We tested different combinations of compliance as well as different reference inputs for the hand/arm system considered. This work has to be intended as a tool for compliant hand designer since it allows to tune compliance at different levels before the real hand realization. Furthermore, the same framework can be used for compliant hand simulation in order to study the interaction with the environmental constrains and to plan complex manipulation tasks.

The flying hand is a robotic hand consisting of a swarm of UAVs able to grasp an object where each UAV contributes to the grasping task with a single contact point at the tooltip. The swarm of robots is teleoperated by a human hand whose fingertip motions are tracked, e.g., using an RGB-D camera. We solve the kinematic dissimilarity of this unique master-slave system using a multi-layered approach that includes: a hand interpreter that translates the fingertip motion in a desired motion for the object to be manipulated; a mapping algorithm that transforms the desired object motions into a suitable set of virtual points deviating from the planned contact points; a compliant force control for the case of quadrotor UAVs that allows to use them as indirect 3D force effectors. Visual feedback is also used as sensory substitution technique to provide a hint on the internal forces exerted on the object. We validate the approach with several human-in-the-loop simulations including the full physical model of the object, contact points and UAVs.

In this paper the problem of a quadrotor that physically interacts with the surrounding environment through a rigid tool is considered. We present a theoretical design that allows to exert an arbitrary 3D force by using a standard near-hovering controller that was originally developed for contact-free flight control. This is achieved by analytically solving the nonlinear system that relates the quadrotor state, the force exerted by the rigid tool on the environment, and the near-hovering controller action at the equilibrium points, during any generic contact. Stability of the equilibria for the most relevant actions (pushing, releasing, lifting, dropping, and left-right shifting) are proven by means of numerical analysis using the indirect Lyapunov method. An experimental platform, including a suitable tool design, has been developed and used to validate the theory with preliminary experiments.

Replicating the human hand capabilities is a great challenge in telemanipulation as well as in autonomous grasping and manipulation. One of the main issues is the difference between human and robotic hands in terms of kinematic structure, which does not allow a direct correlation of the joints. We recently proposed an object-based mapping algorithm able to replicate on several robotic hand models the human hand synergies. In such approach the virtual object shapes were a-priori defined (e.g. a sphere or an ellipsoid) and the transformation was represented as the composition of a rigid body motion and a scale variation. In this work, we introduce a generalization of the object-based mapping that overcomes the definition of a shape for the virtual object. We consider only a set of reference points on the hands. We estimate a homogeneous transformation matrix that represents how the human hand motion changes its reference point positions. The same transformation is then imposed to the reference points on the robotic hand and the joints values obtained through a kinematic inversion technique. The mapping approach is suitable also for telemanipulation scenarios where the hand joint motions are combined with a wrist displacement.

SynGrasp is a MATLAB toolbox developed for the analysis of grasping, suitable both for robotic and human hands. It includes functions for the definition of hand kinematic structure and of the contact points with a grasped object. The coupling between joints induced by an underactuated control can be modeled. The hand modeling allows to define compliance at the contact, joint and actuator levels. The provided analysis functions can be used to investigate the main grasp properties: controllable forces and object displacement, manipulability analysis, grasp quality measures. Functions for the graphical representation of the hand, the object and the main analysis results are provided.

This paper presents a bilateral telemanipulation framework where the master and slave sub-systems have different kinematic structures. A virtual object is defined on the master and slave sides and used to capture the human hand motion and to compute the related force feedback. The force feedback is determined imposing that the same wrench acts on the master and slave virtual objects. An abstraction from the sub-system structures is obtained focusing on the effects produced on the manipulated object. The proposed approach has been tested with an experimental setup consisting of two haptic interfaces able to capture index and thumb motions on the master side and a DLR-HIT Hand II as slave sub-system.

One of the major limitations to the use of advanced robotic hands in industries is the complexity of the control system design due to the large number of motors needed to actuate their degrees of freedom. It is our belief that the development of a unified control framework for robotic hands will allow us to extend the use of these devices in many areas. Borrowing the terminology from software engineering, there is a need for middleware solutions to control the robotic hands independently from their specific kinematics and focus only on the manipulation tasks. To simplify and generalize the control of robotic hands, we take inspiration from studies in neuroscience concerning the sensorimotor organization of the human hand. These studies demonstrated that, notwithstanding the complexity of the hand, a few variables are able to account for most of the variance in the patterns of configurations and movements. The reduced set of parameters that humans effectively use to control their hands, which are known in the literature as synergies, can represent the set of words for the unified control language of robotic hands, provided that we solve the problem of mapping human hand synergies to actions of the robotic hands. In this study, we propose a mapping designed in the manipulated object domain in order to ensure a high level of generality with respect to the many dissimilar kinematics of robotic hands. The role of the object is played by a virtual sphere, whose radius and center position change dynamically, and the role of the human hand is played by a hand model referred to as “paradigmatic hand,” which is able to capture the idea of synergies in human hands.