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In this paper, the problem of online estimation of the mechanical impedance during the contact of a robotic system with an unknown environment is considered. This problem is of great interest when controlling a robot in an unstructured and unknown environment, such as in telemanipulation tasks, since it can be easily shown that the exploitation of the(More)
Rendering stiff virtual objects remains a core challenge in the field of haptics. A study of this problem is presented, which relates the maximum achievable object stiffness to the elements of the control loop. In particular, we examine how the sampling rate and quantization of position measurements interact with the inertia, natural viscous, and Coulomb(More)
This paper describes a novel actuation system for very compact and light-weight robotic devices, like artificial hands. The actuation concept presented here allows the implementation of powerful tendon-based driving systems, using as actuators small-size DC motors characterized by high speed and low torque. After the presentation of the basic concept of(More)
The possibility of operating in remote environments by means of telecontrolled systems has always been considered of relevant interest in robotics. For this reason, in the literature a number of different control schemes has been proposed for telemanipulation systems, based on several criteria such as passivity, compliance, predictive or adaptive control,(More)
The first part of this paper describes the development of a humanoid robot hand based on an endoskeleton made of rigid links connected with elastic hinges, actuated by sheath routed tendons and covered by continuous compliant pulps. The project is called UB Hand 3 (University of Bologna Hand, 3rd version) and aims to reduce the mechanical complexity of(More)
—In this paper, we study the interconnection of two robots, which are modeled as port-controlled Hamiltonian systems through a transmission line with time delay. There will be no analysis of the time delay, but its presence justifies the use of scattering variables to preserve passivity. The contributions of the paper are twofold: first, a geometrical,(More)
In this paper, the tendon-sheath driving system for a robotic hand is presented and its force transmission characteristics are analyzed. The use of tendon-based transmission permits to reduce the size and the complexity of the actuation chain in many mechanical devices. A simple static model that describes the tendon-sheath driving system is presented, and(More)