Sampled data systems passivity and discrete port-Hamiltonian systems

In this paper, we present a novel way to approach the interconnection of a continuous and a discrete time physical system first presented in [1][2] [3]. This is done in a way which preserves passivity of the coupled system independently of the sampling time T. This strategy can be used both in the field of telemanipulation, for the implementation of a passive master/slave system on a digital transmission line with varying time delays and possible loss of packets (e.g., the Internet), and in the field of haptics, where the virtual environment should `feel¿ like a physical equivalent system

DESIGN AND INTEGRATION OF A HUMAN-ROBOT PHYSICAL INTERACTION PLATFORM WITH PURPOSES OF MEDICAL DIAGNOSIS AND REHABILITATION OF UPPER LIMB

In this paper a human-robot physical interaction system with purposes of diagnosis and rehabilitation of upper limb is proposed.Anunderactuatedhaptic device with six degrees of freedom is used, with low inertia and low joint friction.Adaptive control technique is used for passive haptic guidance and active exploration, in order to compensate the dynamic uncertainty of the human operator in the loop.To validate the experimental platform, a procedure is established with three steps: i) knowledge of the haptic interface (interaction with the kinematic virtual environment), ii) navigation in a virtual pipe with changes in the geometric characteristics (verification of position, velocity, collisions and runtime), and iii) haptic guidance in a structured path based on a clinical protocol (study of convergence and energy).Environmental conditions such as temperature, humidity, lighting and noise are characterizedwith purposes to define experimental conditions.In this work, we assess based on the NASA-TLX protocol,the workload perception of simple temporal-spatial tasks

DESIGN AND INTEGRATION OF A HUMAN-ROBOT PHYSICAL INTERACTION PLATFORM WITH PURPOSES OF MEDICAL DIAGNOSIS AND REHABILITATION OF UPPER LIMB

In this paper a human-robot physical interaction system with purposes of diagnosis and rehabilitation of upper limb is proposed.Anunderactuatedhaptic device with six degrees of freedom is used, with low inertia and low joint friction.Adaptive control technique is used for passive haptic guidance and active exploration, in order to compensate the dynamic uncertainty of the human operator in the loop.To validate the experimental platform, a procedure is established with three steps: i) knowledge of the haptic interface (interaction with the kinematic virtual environment), ii) navigation in a virtual pipe with changes in the geometric characteristics (verification of position, velocity, collisions and runtime), and iii) haptic guidance in a structured path based on a clinical protocol (study of convergence and energy).Environmental conditions such as temperature, humidity, lighting and noise are characterizedwith purposes to define experimental conditions.In this work, we assess based on the NASA-TLX protocol,the workload perception of simple temporal-spatial tasks

Design of a New Bilayer Multipole Electromagnetic Brake System for a Haptic Interface

This paper deals with the design, simulation and experimental verification of a new bilayer multipole electromagnetic brake. The design utilizes the superposition principle of magnetic flux across the inner and outer layers of axially-oriented electromagnetic poles to provide gradual braking about the single axis of rotation. The braking principle exploits the Coulomb friction between the two rigid contact surfaces. Compared with conventional, multi-pole, multi-layer type radial brakes in haptic applications, the proposed design provides high fidelity of free motion through an absolutely disconnected rotor. The design also provides a wide operating range by delaying the saturation limit of a magnetic circuit for a wide range of input power. In this paper, the analytical model of the brake is derived and compared with the FEM-based simulation results. The optimal design obtained from multi-objective optimization was experimentally verified for its capability in haptic applications.This work was supported by the Technology Innovation Program (or Industrial Strategic Technology Development Program-Artificial intelligence bio-robot medical convergence project) (20001257, Artificial intelligence algorithm based vascular intervention robot system for reducing radiation exposure and achieving 0.5 mm accuracy)—funded by the Ministry of Trade, Industry and Energy(MOTIE, Korea), the Ministry of Health and Welfare(MOHW), the Ministry of Science and ICT (MSIT) and the Korean Evaluation Institute of Industrial Technology (KEIT); the Technology Innovation Program (10052980, Development of micro-robotic system for surgical treatment of chronic total occlusion)—funded by the Ministry of Trade, Industry and Energy (MI, Korea); and the WC300 R&D Program (S2482672)—funded by the Small and Medium Business Administration (SMBA, KOREA)

MetaSpace II: Object and full-body tracking for interaction and navigation in social VR

MetaSpace II (MS2) is a social Virtual Reality (VR) system where multiple users can not only see and hear but also interact with each other, grasp and manipulate objects, walk around in space, and get tactile feedback. MS2 allows walking in physical space by tracking each user's skeleton in real-time and allows users to feel by employing passive haptics i.e., when users touch or manipulate an object in the virtual world, they simultaneously also touch or manipulate a corresponding object in the physical world. To enable these elements in VR, MS2 creates a correspondence in spatial layout and object placement by building the virtual world on top of a 3D scan of the real world. Through the association between the real and virtual world, users are able to walk freely while wearing a head-mounted device, avoid obstacles like walls and furniture, and interact with people and objects. Most current virtual reality (VR) environments are designed for a single user experience where interactions with virtual objects are mediated by hand-held input devices or hand gestures. Additionally, users are only shown a representation of their hands in VR floating in front of the camera as seen from a first person perspective. We believe, representing each user as a full-body avatar that is controlled by natural movements of the person in the real world (see Figure 1d), can greatly enhance believability and a user's sense immersion in VR.Comment: 10 pages, 9 figures. Video: http://living.media.mit.edu/projects/metaspace-ii

Discrete port-Hamiltonian systems: mixed interconnections

Either from a control theoretic viewpoint or from an analysis viewpoint it is necessary to convert smooth systems to discrete systems, which can then be implemented on computers for numerical simulations. Discrete models can be obtained either by discretizing a smooth model, or by directly modeling at the discrete level itself. The goal of this paper is to apply a previously developed discrete modeling technique to study the interconnection of continuous systems with discrete ones in such a way that passivity is preserved. Such a theory has potential applications, in the field of haptics, telemanipulation etc. It is shown that our discrete modeling theory can be used to formalize previously developed techniques for obtaining passive interconnections of continuous and discrete systems

Quantifying perception of nonlinear elastic tissue models using multidimensional scaling

Simplified soft tissue models used in surgical simulations cannot perfectly reproduce all material behaviors. In particular, many tissues exhibit the Poynting effect, which results in normal forces during shearing of tissue and is only observed in nonlinear elastic material models. In order to investigate and quantify the role of the Poynting effect on material discrimination, we performed a multidimensional scaling (MDS) study. Participants were presented with several pairs of shear and normal forces generated by a haptic device during interaction with virtual soft objects. Participants were asked to rate the similarity between the forces felt. The selection of the material parameters – and thus the magnitude of the shear\ud and normal forces – was based on a pre-study prior to the MDS experiment. It was observed that for nonlinear elastic tissue models exhibiting the Poynting effect, MDS analysis indicated that both shear and normal forces affect user perception